International Nuclear Information System (INIS)
Asa'd, Z.; Coupland, M.; Davis, D.G.; Duff, B.G.; Gjerpe, I.; Heymann, F.F.; Imrie, D.C.; Lowndes, R.; Lush, G.J.; Phillips, M.; Baglin, C.; Poulet, M.; Yvert, M.; Benso, S.; Buzzo, A.; Ferroni, S.; Gracco, V.; Macri, M.; Santroni, A.; Brobakken, K.; Bugge, L.; Buran, T.; Fearnley, T.; Helgaker, P.; Kirsebom, K.; Moe, A.; Soerensen, S.O.; Hansen, J.D.; Myrheim, J.; Skjevling, G.
1982-01-01
Measurements of the differential elastic cross sections for π - p scattering at incident momenta of 20 and 50 GeV/c and π + p at 50 GeV/c in the momentum transfer range 0.7 2 are presented. The data are compared with various models of elastic scattering. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Asa' d, Z.; Coupland, M.; Davis, D.G.; Duff, B.G.; Gjerpe, I.; Heymann, F.F.; Imrie, D.C.; Lowndes, R.; Lush, G.J.; Phillips, M. (University Coll., London (UK))
1982-12-09
Measurements of the differential elastic cross sections for ..pi../sup -/p scattering at incident momenta of 20 and 50 GeV/c and ..pi../sup +/p at 50 GeV/c in the momentum transfer range 0.7 < vertical stroketvertical stroke < 8.0 (GeV/c)/sup 2/ are presented. The data are compared with various models of elastic scattering.
International Nuclear Information System (INIS)
Pripstein, M.
1975-06-01
The discussion of pion charge-exchange and hadron production at large transverse momenta includes the physics motivation, the experimental method event selection criteria, results for the reaction π - p → nπ 0 (eta)
Large-angle production of charged pions with incident pion beams on nuclear targets
Apollonio, M.; Bagulya, A.; Barr, G.; Blondel, A.; Bobisut, F.; Bogomilov, M.; Bonesini, M.; Booth, C.; Borghi, S.; Bunyatov, S.; Burguet-Castell, J.; Catanesi, M.G.; Cervera-Villanueva, A.; Chimenti, P.; Coney, L.; Di Capua, E.; Dore, U.; Dumarchez, J.; Edgecock, R.; Ellis, M.; Ferri, F.; Gastaldi, U.; Giani, S.; Giannini, G.; Gibin, D.; Gilardoni, S.; Gorbunov, P.; Gossling, C.; Gomez-Cadenas, J.J.; Grant, A.; Graulich, J.S.; Gregoire, G.; Grichine, V.; Grossheim, A.; Guglielmi, A.; Howlett, L.; Ivanchenko, A.; Ivanchenko, V.; Kayis-Topaksu, A.; Kirsanov, M.; Kolev, D.; Krasnoperov, A.; Martin-Albo, J.; Meurer, C.; Mezzetto, M.; Mills, G.B.; Morone, M.C.; Novella, P.; Orestano, D.; Palladino, V.; Panman, J.; Papadopoulos, I.; Pastore, F.; Piperov, S.; Polukhina, N.; Popov, B.; Prior, G.; Radicioni, E.; Schmitz, D.; Schroeter, R.; Skoro, G.; Sorel, M.; Tcherniaev, E.; Temnikov, P.; Tereschenko, V.; Tonazzo, A.; Tortora, L.; Tsenov, R.; Tsukerman, I.; Vidal-Sitjes, G.; Wiebusch, C.; Zucchelli, P.
2009-01-01
Measurements of the double-differential pi+/- production cross-section in the range of momentum 100 MeV/c <= p <= 800 MeV/c and angle 0.35 rad <= theta <= 2.15 rad using pi+/- beams incident on beryllium, aluminium, carbon, copper, tin, tantalum and lead targets are presented. The data were taken with the large acceptance HARP detector in the T9 beam line of the CERN PS. The secondary pions were produced by beams in a momentum range from 3 GeV/c to 12.9 GeV/c hitting a solid target with a thickness of 5% of a nuclear interaction length. The tracking and identification of the produced particles was performed using a small-radius cylindrical time projection chamber (TPC) placed inside a solenoidal magnet. Incident particles were identified by an elaborate system of beam detectors. Results are obtained for the double-differential cross-sections d2sigma/dpdtheta at six incident beam momenta. Data at 3 GeV/c, 5 GeV/c, 8 GeV/c, and 12 GeV/c are available for all targets while additional data at 8.9 GeV/...
Inclusive eta production at large transverse momenta
International Nuclear Information System (INIS)
Donaldson, G.J.; Gordon, H.A.; Lai, K.; Stumer, I.; Barnes, A.V.; Mellema, D.J.; Tollestrup, A.V.; Walker, R.L.; Dahl, O.; Johnson, R.; Ogawa, A.; Pripstein, M.; Shannon, S.
1978-01-01
We have measured the ratio of inclusive production of eta to π 0 at transverse momenta above 1.5 GeV/c. Results are presented for various meson and proton beams with momenta of 100, 200, and 300 GeV/c incident upon a hydrogen target. The eta/π 0 production ratio is found to be independent of incident beam momentum and of the transverse and longitudinal momenta of production. The ratio for pion- and proton-induced reactions is 0.44 +- 0.05; for kaons, it is 0.74 +- 0.12
Study of the incident pion deflection in passing through atomic nucleus
International Nuclear Information System (INIS)
Strugalski, Z.; Pawlak, T.; Pluta, J.
1982-01-01
Pion-xenon nucleus collision events at 3.5 GeV/c momentum are studied in which the incident pion is deflected only, without particle production; the deflection is accompanied by emission of nucleons. The multiplicity of the protons emitted is a measure of the nuclear matter layer thickness passed by the pion. It can be concluded that: a) a definite simple relation exists between the pion deflection angle and the thickness of the nuclear matter layer traversed by this pion; b) the deflection angle of the incident pion increases in a definite manner with increasing the thickness of the nuclear matter layer traversed by this pion; c) the average kinetic energy, average longitudinal momentum and average transverse momentum of the protons emitted do not depend on the pion deflection angle
Apollonio, M.; Bagulya, A.; Barr, G.; Blondel, A.; Bobisut, F.; Bogomilov, M.; Bonesini, M.; Booth, C.; Borghi, S.; Bunyatov, S.; Burguet-Castell, J.; Catanesi, M.G.; Cervera-Villanueva, A.; Chimenti, P.; Coney, L.; Di Capua, E.; Dore, U.; Dumarchez, J.; Edgecock, R.; Ellis, M.; Ferri, F.; Gastaldi, U.; Giani, S.; Giannini, G.; Gibin, D.; Gilardoni, S.; Gorbunov, P.; Gossling, C.; Gomez-Cadenas, J.J.; Grant, A.; Graulich, J.S.; Gregoire, G.; Grichine, V.; Grossheim, A.; Guglielmi, A.; Howlett, L.; Ivanchenko, A.; Ivanchenko, V.; Kayis-Topaksu, A.; Kirsanov, M.; Kolev, D.; Krasnoperov, A.; Martin-Albo, J.; Meurer, C.; Mezzetto, M.; Mills, G.B.; Morone, M.C.; Novella, P.; Orestano, D.; Palladino, V.; Panman, J.; Papadopoulos, I.; Pastore, F.; Piperov, Stefan; Polukhina, N.; Popov, B.; Prior, G.; Radicioni, E.; Schmitz, D.; Schroeter, R.; Skoro, G; Sorel, M.; Tcherniaev, E.; Temnikov, P.; Tereschenko, V.; Tonazzo, A.; Tortora, L.; Tsenov, R.; Tsukerman, I.; Vidal-Sitjes, G.; Wiebusch, C.; Zucchelli, P.
2009-01-01
Measurements of the double-differential $\\pi^{\\pm}$ production cross-section in the range of momentum 0.5 GeV/c < p < 8.0 GeV/c and angle 0.025 rad < theta < 0.25 rad in interactions of charged pions on beryllium, carbon, aluminium, copper, tin, tantalum and lead are presented. These data represent the first experimental campaign to systematically measure forward pion hadroproduction. The data were taken with the large acceptance HARP detector in the T9 beam line of Incident particles, impinging on a 5% nuclear interaction length target, were identified by an elaborate system of beam detectors. The tracking and identification of the produced particles was performed using the forward spectrometer of the HARP detector. Results are obtained for the double-differential cross-sections mainly at four incident pion beam momenta (3 GeV/c, 5 GeV/c, 8 GeV/c and 12 GeV/c). The measurements are compared with the GEANT4 and MARS Monte Carlo simulation. the CERN PS.
Apollonio, M.; Bagulya, A.; Barr, G.; Blondel, A.; Bobisut, F.; Bogomilov, M.; Bonesini, M.; Booth, C.; Borghi, S.; Bunyatov, S.; Burguet-Castell, J.; Catanesi, M.G.; Cervera-Villanueva, A.; Chimenti, P.; Coney, L.; Di Capua, E.; Dore, U.; Dumarchez, J.; Edgecock, R.; Ellis, M.; Ferri, F.; Gastaldi, U.; Giani, S.; Giannini, G.; Gibin, D.; Gilardoni, S.; Gorbunov, P.; Gossling, C.; Gomez-Cadenas, J.J.; Grant, A.; Graulich, J.S.; Gregoire, G.; Grichine, V.; Grossheim, A.; Guglielmi, A.; Howlett, L.; Ivanchenko, A.; Ivanchenko, V.; Kayis-Topaksu, A.; Kirsanov, M.; Kolev, D.; Krasnoperov, A.; Martin-Albo, J.; Meurer, C.; Mezzetto, M.; Mills, G.B.; Morone, M.C.; Novella, P.; Orestano, D.; Palladino, V.; Panman, J.; Papadopoulos, I.; Pastore, F.; Piperov, Stefan; Polukhina, N.; Popov, B.; Prior, G.; Radicioni, E.; Schmitz, D.; Schroeter, R.; Serdiouk, V.; Skoro, G; Sorel, M.; Tcherniaev, E.; Temnikov, P.; Tereschenko, V.; Tonazzo, A.; Tortora, L.; Tsenov, R.; Tsukerman, I.; Vidal-Sitjes, G.; Wiebusch, C.; Zucchelli, P.
2009-01-01
Measurements of the double-differential charged pion production cross-section in the range of momentum 0.5 GeV/c < p < 8.0 GeV/c and angle 0.025 rad < theta <0.25 rad in collisions of protons on beryllium, carbon, nitrogen, oxygen, aluminium, copper, tin, tantalum and lead are presented. The data were taken with the large acceptance HARP detector in the T9 beam line of the CERN PS. Incident particles were identified by an elaborate system of beam detectors. The data were taken with thin targets of 5% of a nuclear interaction length. The tracking and identification of the produced particles was performed using the forward system of the HARP experiment. Results are obtained for the double-differential cross section mainly at four incident proton beam momenta (3 GeV/c, 5 GeV/c, 8 GeV/c and 12 GeV/c). Measurements are compared with the GEANT4 and MARS Monte Carlo generators. A global parametrization is provided as an approximation of all the collected datasets which can serve as a tool for quick yield...
Apollonio, M.; Bagulya, A.; Barr, G.; Blondel, A.; Bobisut, F.; Bogomilov, M.; Bonesini, M.; Booth, C.; Borghi, S.; Bunyatov, S.; Burguet-Castell, J.; Catanesi, M.G.; Cervera-Villanueva, A.; Chimenti, P.; Coney, L.; Di Capua, E.; Dore, U.; Dumarchez, J.; Edgecock, R.; Ellis, M.; Ferri, F.; Gastaldi, U.; Giani, S.; Giannini, G.; Gibin, D.; Gilardoni, S.; Gorbunov, P.; Gossling, C.; Gomez-Cadenas, J.J.; Grant, A.; Graulich, J.S.; Gregoire, G.; Grichine, V.; Grossheim, A.; Guglielmi, A.; Howlett, L.; Ivanchenko, A.; Ivanchenko, V.; Kayis-Topaksu, A.; Kirsanov, M.; Kolev, D.; Krasnoperov, A.; Martin-Albo, J.; Meurer, C.; Mezzetto, M.; Mills, G.B.; Morone, M.C.; Novella, P.; Orestano, D.; Palladino, V.; Panman, J.; Papadopoulos, I.; Pastore, F.; Piperov, Stefan; Polukhina, N.; Popov, B.; Prior, G.; Radicioni, E.; Schmitz, D.; Schroeter, R.; Skoro, G; Sorel, M.; Tcherniaev, E.; Temnikov, P.; Tereschenko, V.; Tonazzo, A.; Tortora, L.; Tsenov, R.; Tsukerman, I.; Vidal-Sitjes, G.; Wiebusch, C.; Zucchelli, P.
2010-01-01
Measurements of the double-differential proton production cross-section in the range of momentum 0.5 GeV/c leq p le 8.0 GeV/c and angle 0.05 rad leq heta le 0.25 rad in collisions of charged pions and protons on beryllium, carbon, aluminium, copper,tin, tantalum and lead are presented. The data were taken with the large acceptance HARP detector in the T9 beam line of the CERN Proton Synchrotron. Incident particles were identified by an elaborate system of beam detectors and impinged on a target of 5% of a nuclear interaction length.The tracking and identification of the produced particles was performed using the forward spectrometer of the HARP experiment. Results are obtained for the double-differential cross-sections mainly at four incident beam momenta (3 GeV/c, 5 GeV/c, 8 GeV/c and 12 GeV/c). Measurements are compared with predictions of the GEANT4 and MARS Monte Carlo generators
Apollonio, M.; Bagulya, A.; Barr, G.; Blondel, A.; Bobisut, F.; Bogomilov, M.; Bonesini, M.; Booth, C.; Borghi, S.; Bunyatov, S.; Burguet-Castell, J.; Catanesi, M.G.; Cervera-Villanueva, A.; Chimenti, P.; Coney, L.; Di Capua, E.; Dore, U.; Dumarchez, J.; Edgecock, R.; Ellis, M.; Ferri, F.; Gastaldi, U.; Giani, S.; Giannini, G.; Gibin, D.; Gilardoni, S.; Gorbunov, P.; Gossling, C.; Gomez-Cadenas, J.J.; Grant, A.; Graulich, J.S.; Gregoire, G.; Grichine, V.; Grossheim, A.; Guglielmi, A.; Howlett, L.; Ivanchenko, A.; Ivanchenko, V.; Kayis-Topaksu, A.; Kirsanov, M.; Kolev, D.; Krasnoperov, A.; Martin-Albo, J.; Meurer, C.; Mezzetto, M.; Mills, G.B.; Morone, M.C.; Novella, P.; Orestano, D.; Palladino, V.; Panman, J.; Papadopoulos, I.; Pastore, F.; Piperov, Stefan; Polukhina, N.; Popov, B.; Prior, G.; Radicioni, E.; Schmitz, D.; Schroeter, R.; Skoro, G; Sorel, M.; Tcherniaev, E.; Temnikov, P.; Tereschenko, V.; Tonazzo, A.; Tortora, L.; Tsenov, R.; Tsukerman, I.; Vidal-Sitjes, G.; Wiebusch, C.; Zucchelli, P.
2009-01-01
The HARP collaboration has presented measurements of the double-differential pi+/pi- production cross-section in the range of momentum 100 MeV/c <= p 800 MeV/c and angle 0.35 rad <= theta <= 2.15 rad with proton beams hitting thin nuclear targets. In many applications the extrapolation to long targets is necessary. In this paper the analysis of data taken with long (one interaction length) solid cylindrical targets made of carbon, tantalum and lead is presented. The data were taken with the large acceptance HARP detector in the T9 beam line of the CERN PS. The secondary pions were produced by beams of protons with momenta 5 GeV/c, 8 GeV/c and 12 GeV/c. The tracking and identification of the produced particles were performed using a small-radius cylindrical time projection chamber (TPC) placed inside a solenoidal magnet. Incident protons were identified by an elaborate system of beam detectors. Results are obtained for the double-differential yields per target nucleon d2 sigma / dp dtheta. The measure...
Directory of Open Access Journals (Sweden)
B. Abelev
2014-09-01
Full Text Available Transverse momentum spectra of π±, K± and p(p¯ up to pT=20 GeV/c at mid-rapidity in pp, peripheral (60–80% and central (0–5% Pb–Pb collisions at sNN=2.76 TeV have been measured using the ALICE detector at the Large Hadron Collider. The proton-to-pion and the kaon-to-pion ratios both show a distinct peak at pT≈3 GeV/c in central Pb–Pb collisions. Below the peak, pT10 GeV/c particle ratios in pp and Pb–Pb collisions are in agreement and the nuclear modification factors for π±, K± and p(p¯ indicate that, within the systematic and statistical uncertainties, the suppression is the same. This suggests that the chemical composition of leading particles from jets in the medium is similar to that of vacuum jets.
Abelev, B.; Adam, J.; Adamová, D.; Aggarwal, M. M.; Aglieri Rinella, G.; Agnello, M.; Agostinelli, A.; Agrawal, N.; Ahammed, Z.; Ahmad, N.; Ahmad Masoodi, A.; Ahmed, I.; Ahn, S. U.; Ahn, S. A.; Aimo, I.; Aiola, S.; Ajaz, M.; Akindinov, A.; Aleksandrov, D.; Alessandro, B.; Alexandre, D.; Alici, A.; Alkin, A.; Alme, J.; Alt, T.; Altini, V.; Altinpinar, S.; Altsybeev, I.; Alves Garcia Prado, C.; Andrei, C.; Andronic, A.; Anguelov, V.; Anielski, J.; Antičić, T.; Antinori, F.; Antonioli, P.; Aphecetche, L.; Appelshäuser, H.; Arbor, N.; Arcelli, S.; Armesto, N.; Arnaldi, R.; Aronsson, T.; Arsene, I. C.; Arslandok, M.; Augustinus, A.; Averbeck, R.; Awes, T. C.; Azmi, M. D.; Bach, M.; Badalà, A.; Baek, Y. W.; Bagnasco, S.; Bailhache, R.; Bairathi, V.; Bala, R.; Baldisseri, A.; Baltasar Dos Santos Pedrosa, F.; Bán, J.; Baral, R. C.; Barbera, R.; Barile, F.; Barnaföldi, G. G.; Barnby, L. S.; Barret, V.; Bartke, J.; Basile, M.; Bastid, N.; Basu, S.; Bathen, B.; Batigne, G.; Batyunya, B.; Batzing, P. C.; Baumann, C.; Bearden, I. G.; Beck, H.; Bedda, C.; Behera, N. K.; Belikov, I.; Bellini, F.; Bellwied, R.; Belmont-Moreno, E.; Bencedi, G.; Beole, S.; Berceanu, I.; Bercuci, A.; Berdnikov, Y.; Berenyi, D.; Berger, M. E.; Bertens, R. A.; Berzano, D.; Betev, L.; Bhasin, A.; Bhati, A. K.; Bhattacharjee, B.; Bhom, J.; Bianchi, L.; Bianchi, N.; Bianchin, C.; Bielčík, J.; Bielčíková, J.; Bilandzic, A.; Bjelogrlic, S.; Blanco, F.; Blau, D.; Blume, C.; Bock, F.; Bogdanov, A.; Bøggild, H.; Bogolyubsky, M.; Böhmer, F. V.; Boldizsár, L.; Bombara, M.; Book, J.; Borel, H.; Borissov, A.; Bornschein, J.; Bossú, F.; Botje, M.; Botta, E.; Böttger, S.; Braun-Munzinger, P.; Bregant, M.; Breitner, T.; Broker, T. A.; Browning, T. A.; Broz, M.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Bufalino, S.; Buncic, P.; Busch, O.; Buthelezi, Z.; Caffarri, D.; Cai, X.; Caines, H.; Caliva, A.; Calvo Villar, E.; Camerini, P.; Canoa Roman, V.; Carena, F.; Carena, W.; Carminati, F.; Casanova Díaz, A.; Castillo Castellanos, J.; Casula, E. A R; Catanescu, V.; Cavicchioli, C.; Ceballos Sanchez, C.; Cepila, J.; Cerello, P.; Chang, B.; Chapeland, S.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chibante Barroso, V.; Chinellato, D. D.; Chochula, P.; Chojnacki, M.; Choudhury, S.; Christakoglou, P.; Christensen, C. H.; Christiansen, P.; Chujo, T.; Chung, S. U.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Colamaria, F.; Colella, D.; Collu, A.; Colocci, M.; Conesa Balbastre, G.; Conesa del Valle, Z.; Connors, M. E.; Contin, G.; Contreras, J. G.; Cormier, T. M.; Corrales Morales, Y.; Cortese, P.; Cortés Maldonado, I.; Cosentino, M. R.; Costa, F.; Crochet, P.; Cruz Albino, R.; Cuautle, E.; Cunqueiro, L.; Dainese, A.; Dang, R.; Danu, A.; Das, D.; Das, I.; Das, K.; Das, S.; Dash, A.; Dash, S.; De, S.; Delagrange, H.; Deloff, A.; Dénes, E.; D'Erasmo, G.; de Barros, G. O V; De Caro, A.; de Cataldo, G.; de Cuveland, J.; De Falco, A.; De Gruttola, D.; De Marco, N.; De Pasquale, S.; de Rooij, R.; Diaz Corchero, M. A.; Dietel, T.; Divià, R.; Di Bari, D.; Di Liberto, S.; Di Mauro, A.; Di Nezza, P.; Djuvsland, O.; Dobrin, A.; Dobrowolski, T.; Domenicis Gimenez, D.; Dönigus, B.; Dordic, O.; Dørheim, S.; Dubey, A. K.; Dubla, A.; Ducroux, L.; Dupieux, P.; Dutta Majumdar, A. K.; Ehlers, R. J.; Elia, D.; Engel, H.; Erazmus, B.; Erdal, H. A.; Eschweiler, D.; Espagnon, B.; Estienne, M.; Esumi, S.; Evans, D.; Evdokimov, S.; Eyyubova, G.; Fabris, D.; Faivre, J.; Falchieri, D.; Fantoni, A.; Fasel, M.; Fehlker, D.; Feldkamp, L.; Felea, D.; Feliciello, A.; Feofilov, G.; Ferencei, J.; Fernández Téllez, A.; Ferreiro, E. G.; Ferretti, A.; Festanti, A.; Figiel, J.; Figueredo, M. A S; Filchagin, S.; Finogeev, D.; Fionda, F. M.; Fiore, E. M.; Floratos, E.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Francescon, A.; Frankenfeld, U.; Fuchs, U.; Furget, C.; Fusco Girard, M.; Gaardhøje, J. J.; Gagliardi, M.; Gago, A. M.; Gallio, M.; Gangadharan, D. R.; Ganoti, P.; Garabatos, C.; Garcia-Solis, E.; Gargiulo, C.; Garishvili, I.; Gerhard, J.; Germain, M.; Gheata, A.; Gheata, M.; Ghidini, B.; Ghosh, P.; Ghosh, S. K.; Gianotti, P.; Giubellino, P.; Gladysz-Dziadus, E.; Glässel, P.; Gomez, R.; González-Zamora, P.; Gorbunov, S.; Görlich, L.; Gotovac, S.; Graczykowski, L. K.; Grajcarek, R.; Grelli, A.; Grigoras, A.; Grigoras, C.; Grigoriev, V.; Grigoryan, A.; Grigoryan, S.; Grinyov, B.; Grion, N.; Grosse-Oetringhaus, J. F.; Grossiord, J. Y.; Grosso, R.; Guber, F.; Guernane, R.; Guerzoni, B.; Guilbaud, M.; Gulbrandsen, K.; Gulkanyan, H.; Gunji, T.; Gupta, A.; Gupta, R.; Khan, K. H.; Haake, R.; Haaland, O.; Hadjidakis, C.; Haiduc, M.; Hamagaki, H.; Hamar, G.; Hanratty, L. D.; Hansen, A.; Harris, J. W.; Hartmann, H.; Harton, A.; Hatzifotiadou, D.; Hayashi, S.; Heckel, S. T.; Heide, M.; Helstrup, H.; Herghelegiu, A.; Herrera Corral, G.; Hess, B. A.; Hetland, K. F.; Hicks, B.; Hippolyte, B.; Hladky, J.; Hristov, P.; Huang, M.; Humanic, T. J.; Hutter, D.; Hwang, D. S.; Ilkaev, R.; Ilkiv, I.; Inaba, M.; Incani, E.; Innocenti, G. M.; Ionita, C.; Ippolitov, M.; Irfan, M.; Ivanov, M.; Ivanov, V.; Ivanytskyi, O.; Jachołkowski, A.; Jacobs, P. M.; Jahnke, C.; Jang, H. J.; Janik, M. A.; Jayarathna, P. H S Y; Jena, S.; Jimenez Bustamante, R. T.; Jones, P. G.; Jung, H.; Jusko, A.; Kalcher, S.; Kalinak, P.; Kalweit, A.; Kamin, J.; Kang, J. H.; Kaplin, V.; Kar, S.; Karasu Uysal, A.; Karavichev, O.; Karavicheva, T.; Karpechev, E.; Kebschull, U.; Keidel, R.; Ketzer, B.; Khan, M. M.; Khan, P.; Khan, S. A.; Khanzadeev, A.; Kharlov, Y.; Kileng, B.; Kim, B.; Kim, D. W.; Kim, D. J.; Kim, J. S.; Kim, M.; Kim, M.; Kim, S.; Kim, T.; Kirsch, S.; Kisel, I.; Kiselev, S.; Kisiel, A.; Kiss, G.; Klay, J. L.; Klein, J.; Klein-Bösing, C.; Kluge, A.; Knichel, M. L.; Knospe, A. G.; Kobdaj, C.; Kofarago, M.; Köhler, M. K.; Kollegger, T.; Kolojvari, A.; Kondratiev, V.; Kondratyeva, N.; Konevskikh, A.; Kovalenko, V.; Kowalski, M.; Kox, S.; Koyithatta Meethaleveedu, G.; Kral, J.; Králik, I.; Kramer, F.; Kravčáková, A.; Krelina, M.; Kretz, M.; Krivda, M.; Krizek, F.; Krus, M.; Kryshen, E.; Krzewicki, M.; Kučera, V.; Kucheriaev, Y.; Kugathasan, T.; Kuhn, C.; Kuijer, P. G.; Kulakov, I.; Kumar, J.; Kurashvili, P.; Kurepin, A.; Kurepin, A. B.; Kuryakin, A.; Kushpil, S.; Kushpil, V.; Kweon, M. J.; Kwon, Y.; Ladron de Guevara, P.; Lagana Fernandes, C.; Lakomov, I.; Langoy, R.; Lara, C.; Lardeux, A.; Lattuca, A.; La Pointe, S. L.; La Rocca, P.; Lea, R.; Leardini, L.; Lee, G. R.; Legrand, I.; Lehnert, J.; Lemmon, R. C.; Lenhardt, M.; Lenti, V.; Leogrande, E.; Leoncino, M.; León Monzón, I.; Lévai, P.; Li, S.; Lien, J.; Lietava, R.; Lindal, S.; Lindenstruth, V.; Lippmann, C.; Lisa, M. A.; Ljunggren, H. M.; Lodato, D. F.; Loenne, P. I.; Loggins, V. R.; Loginov, V.; Lohner, D.; Loizides, C.; Lopez, X.; López Torres, E.; Lu, X. G.; Luettig, P.; Lunardon, M.; Luo, J.; Luparello, G.; Luzzi, C.; Ma, R.; Maevskaya, A.; Mager, M.; Mahapatra, D. P.; Maire, A.; Malaev, M.; Maldonado Cervantes, I.; Malinina, L.; Mal'Kevich, D.; Malzacher, P.; Mamonov, A.; Manceau, L.; Manko, V.; Manso, F.; Manzari, V.; Marchisone, M.; Mareš, J.; Margagliotti, G. V.; Margotti, A.; Marín, A.; Markert, C.; Marquard, M.; Martashvili, I.; Martin, N. A.; Martinengo, P.; Martínez, M. I.; Martínez García, G.; Martin Blanco, J.; Martynov, Y.; Mas, A.; Masciocchi, S.; Masera, M.; Masoni, A.; Massacrier, L.; Mastroserio, A.; Matyja, A.; Mayer, C.; Mazer, J.; Mazumder, R.; Mazzoni, M. A.; Meddi, F.; Menchaca-Rocha, A.; Meninno, E.; Mercado Pérez, J.; Meres, M.; Miake, Y.; Mikhaylov, K.; Milano, L.; Milosevic, J.; Mischke, A.; Mishra, A. N.; Miśkowiec, D.; Mitu, C. M.; Mlynarz, J.; Mohanty, B.; Molnar, L.; Montaño Zetina, L.; Montes, E.; Morando, M.; Moreira De Godoy, D. A.; Moretto, S.; Morreale, A.; Morsch, A.; Muccifora, V.; Mudnic, E.; Muhuri, S.; Mukherjee, M.; Müller, H.; Munhoz, M. G.; Murray, S.; Musa, L.; Musinsky, J.; Nandi, B. K.; Nania, R.; Nappi, E.; Nattrass, C.; Nayak, T. K.; Nazarenko, S.; Nedosekin, A.; Nicassio, M.; Niculescu, M.; Nielsen, B. S.; Nikolaev, S.; Nikulin, S.; Nikulin, V.; Nilsen, B. S.; Noferini, F.; Nomokonov, P.; Nooren, G.; Nyanin, A.; Nystrand, J.; Oeschler, H.; Oh, S.; Oh, S. K.; Okatan, A.; Olah, L.; Oleniacz, J.; Oliveira Da Silva, A. C.; Onderwaater, J.; Oppedisano, C.; Ortiz Velasquez, A.; Oskarsson, A.; Otwinowski, J.; Oyama, K.; Pachmayer, Y.; Pachr, M.; Pagano, P.; Paić, G.; Painke, F.; Pajares, C.; Pal, S. K.; Palmeri, A.; Pant, D.; Papikyan, V.; Pappalardo, G. S.; Park, W. J.; Passfeld, A.; Patalakha, D. I.; Paticchio, V.; Paul, B.; Pawlak, T.; Peitzmann, T.; Pereira Da Costa, H.; Pereira De Oliveira Filho, E.; Peresunko, D.; Pérez Lara, C. E.; Peryt, W.; Pesci, A.; Pestov, Y.; Petráček, V.; Petran, M.; Petris, M.; Petrovici, M.; Petta, C.; Piano, S.; Pikna, M.; Pillot, P.; Pinazza, O.; Pinsky, L.; Piyarathna, D. B.; Płoskoń, M.; Planinic, M.; Pluta, J.; Pochybova, S.; Podesta-Lerma, P. L M; Poghosyan, M. G.; Pohjoisaho, E. H O; Polichtchouk, B.; Poljak, N.; Pop, A.; Porteboeuf-Houssais, S.; Porter, J.; Pospisil, V.; Potukuchi, B.; Prasad, S. K.; Preghenella, R.; Prino, F.; Pruneau, C. A.; Pshenichnov, I.; Puddu, G.; Punin, V.; Putschke, J.; Qvigstad, H.; Rachevski, A.; Raha, S.; Rak, J.; Rakotozafindrabe, A.; Ramello, L.; Raniwala, R.; Raniwala, S.; Räsänen, S. S.; Rascanu, B. T.; Rathee, D.; Rauf, A. W.; Razazi, V.; Read, K. F.; Real, J. S.; Redlich, K.; Reed, R. J.; Rehman, A.; Reichelt, P.; Reicher, M.; Reidt, F.; Renfordt, R.; Reolon, A. R.; Reshetin, A.; Rettig, F.; Revol, J. P.; Reygers, K.; Riabov, V.; Ricci, R. A.; Richert, T.; Richter, M.; Riedler, P.; Riegler, W.; Riggi, F.; Rivetti, A.; Rocco, E.; Rodríguez Cahuantzi, M.; Rodriguez Manso, A.; Røed, K.; Rogochaya, E.; Rohni, S.; Rohr, D.; Röhrich, D.; Romita, R.; Ronchetti, F.; Ronflette, L.; Rosnet, P.; Rossegger, S.; Rossi, A.; Roukoutakis, F.; Roy, A.; Roy, C.; Roy, P.; Rubio Montero, A. J.; Rui, R.; Russo, R.; Ryabinkin, E.; Ryabov, Y.; Rybicki, A.; Sadovsky, S.; Šafařík, K.; Sahlmuller, B.; Sahoo, R.; Sahu, P. K.; Saini, J.; Salgado, C. A.; Salzwedel, J.; Sambyal, S.; Samsonov, V.; Sanchez Castro, X.; Sánchez Rodríguez, F. J.; Šándor, L.; Sandoval, A.; Sano, M.; Santagati, G.; Sarkar, D.; Scapparone, E.; Scarlassara, F.; Scharenberg, R. P.; Schiaua, C.; Schicker, R.; Schmidt, C.; Schmidt, H. R.; Schuchmann, S.; Schukraft, J.; Schulc, M.; Schuster, T.; Schutz, Y.; Schwarz, K.; Schweda, K.; Scioli, G.; Scomparin, E.; Scott, P. A.; Scott, R.; Segato, G.; Seger, J. E.; Selyuzhenkov, I.; Seo, J.; Serradilla, E.; Sevcenco, A.; Shabetai, A.; Shabratova, G.; Shahoyan, R.; Shangaraev, A.; Sharma, N.; Sharma, S.; Shigaki, K.; Shtejer, K.; Sibiriak, Y.; Siddhanta, S.; Siemiarczuk, T.; Silvermyr, D.; Silvestre, C.; Simatovic, G.; Singaraju, R.; Singh, R.; Singha, S.; Singhal, V.; Sinha, B. C.; Sinha, T.; Sitar, B.; Sitta, M.; Skaali, T. B.; Skjerdal, K.; Smakal, R.; Smirnov, N.; Snellings, R. J M; Søgaard, C.; Soltz, R.; Song, J.; Song, M.; Soramel, F.; Sorensen, S.; Spacek, M.; Sputowska, I.; Spyropoulou-Stassinaki, M.; Srivastava, B. K.; Stachel, J.; Stan, I.; Stefanek, G.; Steinpreis, M.; Stenlund, E.; Steyn, G.; Stiller, J. H.; Stocco, D.; Stolpovskiy, M.; Strmen, P.; Suaide, A. A P; Subieta Vasquez, M. A.; Sugitate, T.; Suire, C.; Suleymanov, M.; Sultanov, R.; Šumbera, M.; Susa, T.; Symons, T. J M; Szanto de Toledo, A.; Szarka, I.; Szczepankiewicz, A.; Szymanski, M.; Takahashi, J.; Tangaro, M. A.; Tapia Takaki, J. D.; Tarantola Peloni, A.; Tarazona Martinez, A.; Tarzila, M. G.; Tauro, A.; Tejeda Muñoz, G.; Telesca, A.; Terrevoli, C.; Ter Minasyan, A.; Thäder, J.; Thomas, D.; Tieulent, R.; Timmins, A. R.; Toia, A.; Torii, H.; Trubnikov, V.; Trzaska, W. H.; Tsuji, T.; Tumkin, A.; Turrisi, R.; Tveter, T. S.; Ulery, J.; Ullaland, K.; Uras, A.; Usai, G. L.; Vajzer, M.; Vala, M.; Valencia Palomo, L.; Vallero, S.; Vande Vyvre, P.; Vannucci, L.; Van Der Maarel, J.; Van Hoorne, J. W.; van Leeuwen, M.; Vargas, A.; Varma, R.; Vasileiou, M.; Vasiliev, A.; Vechernin, V.; Veldhoen, M.; Velure, A.; Venaruzzo, M.; Vercellin, E.; Vergara Limón, S.; Vernet, R.; Verweij, M.; Vickovic, L.; Viesti, G.; Viinikainen, J.; Vilakazi, Z.; Villalobos Baillie, O.; Vinogradov, A.; Vinogradov, L.; Vinogradov, Y.; Virgili, T.; Viyogi, Y. P.; Vodopyanov, A.; Völkl, M. A.; Voloshin, K.; Voloshin, S. A.; Volpe, G.; von Haller, B.; Vorobyev, I.; Vranic, D.; Vrláková, J.; Vulpescu, B.; Vyushin, A.; Wagner, B.; Wagner, J.; Wagner, V.; Wang, M.; Wang, Y.; Watanabe, D.; Weber, M.; Wessels, J. P.; Westerhoff, U.; Wiechula, J.; Wikne, J.; Wilde, M.; Wilk, G.; Wilkinson, J.; Williams, M. C S; Windelband, B.; Winn, M.; Xiang, C.; Yaldo, C. G.; Yamaguchi, Y.; Yang, H.; Yang, P.; Yang, S.; Yano, S.; Yasnopolskiy, S.; Yi, J.; Yin, Z.; Yoo, I. K.; Yushmanov, I.; Zaccolo, V.; Zach, C.; Zaman, A.; Zampolli, C.; Zaporozhets, S.; Zarochentsev, A.; Závada, P.; Zaviyalov, N.; Zbroszczyk, H.; Zgura, I. S.; Zhalov, M.; Zhang, F.; Zhang, H.; Zhang, X.; Zhang, Y.; Zhao, C.; Zhou, D.; Zhou, F.; Zhou, Y.; Zhu, H.; Zhu, J.; Zhu, J.; Zhu, X.; Zichichi, A.; Zimmermann, A.; Zimmermann, M. B.; Zinovjev, G.; Zoccarato, Y.; Zynovyev, M.; Zyzak, M.
2014-01-01
Transverse momentum spectra of π ±, K ± and p(p-) up to pT = 20 GeV/c at mid-rapidity in pp, peripheral (60-80%) and central (0-5%) Pb-Pb collisions at √sNN=2.76 TeV have been measured using the ALICE detector at the Large Hadron Collider. The proton-to-pion and the kaon-to-pion ratios both show a
Bolshakova, A.; Chelkov, G.; Dedovitch, D.; Elagin, A.; Gostkin, M.; Guskov, A.; Kroumchtein, Z.; Nefedov, Yu.; Nikolaev, K.; Zhemchugov, A.; Dydak, F.; Wotschack, J.; De Min, A.; Ammosov, V.; Gapienko, V.; Koreshev, V.; Semak, A.; Sviridov, Yu.; Usenko, E.; Zaets, V.
2009-01-01
We report on double-differential inclusive cross-sections of the production of secondary protons, charged pions, and deuterons, in the interactions with a 5% $\\lambda_{abs}$ thick stationary tantalum target, of proton and pion beams with momentum from $\\pm{3} GeV/c to \\pm{15} GeV/c$. Results are given for secondary particles with production angles 20° < heta < 125° . They are of particular relevance for the optimization of the design parameters of the proton driver of a neutrino factory.
International Nuclear Information System (INIS)
Fassnacht, P.
1984-01-01
We have studied pion production in nucleus-nucleus collisions at foward angles for about twenty projectile target combinations. The incident energies were below or around 300 MeV/nucleon which is the threshold of the elementary reaction NN → NNπ. The study of the inclusive spectra shows some new ideas: shell effects in pion production, collective resonances excitations. These spectra have been analyzed following different models: hard-scattering models which describe the interaction on the basis of the elementary reaction NN → NNπ, statistical model and the pionic cloud model which is a coherent description of the interaction. In the study of the exclusive reactions, we established some empiric rules concerning the cross-section variations. These exclusive spectra were then analyzed in the framework of two-models: the semi-phenomenological model and the pionic fusion [fr
International Nuclear Information System (INIS)
Abramov, V.V.; Baldin, V.Yu.; Buzulutskov, A.F.
1981-01-01
The process of pion pair production is studied in the 70 GeV pp collisions. The invariant cross section slope of the pp → π + π - + X process as a function of transverse mompsub(T)entum is found to have a break near 1 GeV/c. Fitting the cross section by a sum of two exponents gives the values of powers (12.3+-0.9) (GeV/c) -1 and (8.7+-0.6) (GeV/c) -1 . The experimental points at psub(T)>=1 GeV/c are significantly higher than predictions based on hard scattering models such as quantum chromodynamics and constituent interchange model. The largest disagreement is discovered for calculations of the cross section in the framework of quantum chromodynamics [ru
Pion, pion-pion, and pion-nucleus interactions
Mukhin, K N; Tikhonov, V N
2002-01-01
This survey is devoted to describing the early studies of 1.1. Gurevich on pion physics that were performed by the photoemulsion method and the studies of the pion-pion interaction that were made by his colleagues on the basis of the hydrogen-bubble-chamber and the magnetic-spectrometer method (as well-as on the basis of the photoemulsion method). Two approaches-an extrapolation of experimental data from the physical region to the pion pole and a theoretical calculation based on the Roy integral equations-are used to deduce information about the pion-pion interaction. The first results obtained for pion-pion and pion-nucleus interactions in the experiments that are being currently performed in Brookhaven and at CERN ( pi pi interaction) and at TRIUMF (Canada) and in Brookhaven (pion-nucleus interaction) are presented, along with the existing theoretical concepts in these realms of physics. (80 refs).
Resonance production and decay in pion induced collisions with HADES
Directory of Open Access Journals (Sweden)
Scozzi Federico
2017-01-01
Full Text Available The main goal of the High Acceptance Di-Electron experiment (HADES at GSI is the study of hadronic matter in the 1-3.5 GeV/nucleon incident energy range. HADES results on e+ e− production in proton-nucleus reactions and in nucleus-nucleus collisions demonstrate a strong enhancement of the dilepton yield relative to a reference spectrum obtained from elementary nucleon-nucleon reactions. These observations point to a strong modification of the in-medium ρ spectral function driven by the coupling of the ρ to baryon-resonance hole states. However, to scrutinize this conjecture, a precise study of the role of the ρ meson in electromagnetic baryon-resonance transitions in the time-like region is mandatory. In order to perform this study, HADES has started a dedicated pion-nucleon programme. For the first time a combined measurement of hadronic and dielectron final states have been performed in π−-N reactions at four different pion beam momenta (0.656, 0.69, 0.748 and 0.8 GeV/c. First results on exclusive channels with one pion π−-p and two pions (nπ+π−, pπ−π0 in the final state, which are currently analysed within the partial wave analysis (PWA framework of the Bonn-Gatchina group, are discussed. Finally first results for the dielectron analysis will be shown.
Study of the Production of Single Pions in Pion-proton Collisions near Threshold
2002-01-01
This experiment aims at a complete-kinematics measurement of the processes @p|-p @A @p|-@p|+n and @p|+p @A @p|+@p|+n in the region of incident momenta between 300 MeV/c and 460 MeV/c. It uses the Omicron Spectrometer with detectors placed in the magnetic field close to a 12 atm. hydrogen gas target. The apparatus has an acceptance of 4\\% for the processes to be studied. \\\\ \\\\ Their threshold is at 279 MeV/c and pion production in this region is interesting from the point of view of the determination of transformation properties of the chiral-symmetry-breaking part of the Lagrangian.
Pion structure from lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Javadi Motaghi, Narjes
2015-05-12
In this thesis we use lattice QCD to compute the second Mellin moments of pion generalized parton distributions and pion electromagnetic form factors. For our calculations we are able to analyze a large set of gauge configurations with 2 dynamical flavours using non-perturbatively the improved Wilson-Sheikholeslami-Wohlert fermionic action pion masses ranging down to 151 MeV. By employing improved smearing we were able to suppress excited state contamination. However, our data in the physical quark mass limit show that some excited state contamination remains. We show the non-zero sink momentum is optimal for the computation of the electromagnetic form factors and generalized form factors at finite momenta.
International Nuclear Information System (INIS)
Walter, J.B.; Rebka, G.A. Jr.
1979-03-01
A subroutine, SCATPI, was written which calculates π + p elastic differential cross sections for incident pion kinetic energies between 90 and 310 MeV for π - p. The calculation is based upon the phase shift analysis of Carter, Bugg, and Carter, and is reliable to about 2% for π + p and 3% for π - p differential cross sections. SCATPI also calculates other scattering parameters for the π+-p systems. The calculations are compared with the measurements used in the phase shift analysis, and with selected recent measurements. The use of SCATPI is described. 14 figures, 4 tables
Electromagnetic form factors at large momenta from lattice QCD
International Nuclear Information System (INIS)
Chambers, Alexander J.; Dragos, J.; Michigan State Univ., East Lansing, MI; Horsley, R.
2017-01-01
Accessing hadronic form factors at large momentum transfers has traditionally presented a challenge for lattice QCD simulations. Here we demonstrate how a novel implementation of the Feynman-Hellmann method can be employed to calculate hadronic form factors in lattice QCD at momenta much higher than previously accessible. Our simulations are performed on a single set of gauge configurations with three flavours of degenerate mass quarks corresponding to m π ∼470 MeV. We are able to determine the electromagnetic form factors of the pion and nucleon up to approximately 6 GeV 2 , with results for G E /G M in the proton agreeing well with experimental results.
Energy Technology Data Exchange (ETDEWEB)
Asa' d, Z.; Coupland, M.; Davis, D.G.; Duff, B.G.; Fearnley, T.; Heymann, F.F.; Imrie, D.C.; Lush, G.J.; Phillips, M. (University Coll., London (UK)); Baglin, C.
1985-06-24
Results are presented from experiment WA7 at the CERN SPS, which has measured the elastic differential cross sections of ..pi..sup(+-)p, Ksup(+-)p, anti pp and pp at incident momenta of 20, 30 and 50 GeV/c. The measurements cover the momentum transfer range 0.5 < vertical stroketvertical stroke < 8 (GeV/c)/sup 2/, corresponding to c.m. scattering angles between 10/sup 0/ and 50/sup 0/. The experimental set-up, trigger logic and data analysis are described. The experimental results are compared with existing meson-proton and nucleon-proton data at lower and higher energies covering the medium- and large-vertical stroketvertical stroke region. Some prominent models and their predictions for elastic scattering at WA7 energies and beyond are reviewed, with emphasis on geometrical scaling, factorizing eikonal models, lowest-order QCD and other dynamical exchange-type models. Results for anti pp two-body annihilation into ..pi../sup -/..pi../sup +/ and K/sup -/K/sup +/ at 30 and 50 GeV/c, obtained in parallel with the elastic anti pp data, are also presented.
International Nuclear Information System (INIS)
Asa'd, Z.; Coupland, M.; Davis, D.G.; Duff, B.G.; Fearnley, T.; Heymann, F.F.; Imrie, D.C.; Lush, G.J.; Phillips, M.; Baglin, C.; Guillaud, J.P.; Poulet, M.; Myrheim, J.; Gjerpe, I.K.; Buran, T.; Buzzo, A.; Ferroni, S.; Gracco, V.; Kirsebom, K.; Macri, M.; Santroni, A.; Soersdal, T.
1985-01-01
Results are presented from experiment WA7 at the CERN SPS, which has measured the elastic differential cross sections of πsup(+-)p, Ksup(+-)p, anti pp and pp at incident momenta of 20, 30 and 50 GeV/c. The measurements cover the momentum transfer range 0.5 2 , corresponding to c.m. scattering angles between 10 0 and 50 0 . The experimental set-up, trigger logic and data analysis are described. The experimental results are compared with existing meson-proton and nucleon-proton data at lower and higher energies covering the medium- and large-vertical stroketvertical stroke region. Some prominent models and their predictions for elastic scattering at WA7 energies and beyond are reviewed, with emphasis on geometrical scaling, factorizing eikonal models, lowest-order QCD and other dynamical exchange-type models. Results for anti pp two-body annihilation into π - π + and K - K + at 30 and 50 GeV/c, obtained in parallel with the elastic anti pp data, are also presented. (orig.)
Spin effects at fragmentation of polarized deuterons into cumulative pions
International Nuclear Information System (INIS)
Afanasiev, S.; Arkhipov, V.; Bondarev, V.; Isupov, A.; Khrenov, A.; Kirillov, D.; Ladygin, V.; Litvinenko, A.; Malakhov, A.; Pilipenko, Yu.; Reznikov, S.; Rukoyatkin, P.; Zolin, L.; Daito, I.; Horikawa, N.; Wakai, A.; Doushita, N.; Fukui, S.; Iwata, T.; Kondo, K.
2002-01-01
Tensor analyzing power T 20 of the reaction d-vectorA→π(0 deg.)X was measured in the fragmentation of 9 GeV deuterons into points with the momenta from 3.5 to 5.3 GeV/c at hydrogen, beryllium and carbon targets. This momentum range corresponds to region of cumulative pion production The values of T 20 are found to be small and consistent with positive values in contradiction with the Impulse Approximation calculations based on assuming a direct mechanism of pion production (NN→NNπ). New data on tensor Ayy analyzing power for pion production at the non-zero angle (θ π =135,180mr) with pion transverse momenta up to P t =0.8 GeV/c are presented. Ayy increases with rise of P t in the cumulative region
Determination of some parameters for pion radiobiology studies
Nordell, B; Sullivan, A H; Zielczynski, M
1977-01-01
An experimental investigation of the central axis depth-dose and stopping rate distribution of the SIN biomedical pion beam is reported. The pion stopping rate in a thin disc of tissue-equivalent plastic was determined using a counter telescope. The dose rate at the position of this disc 'target' was measured using a specially designed parallel-plate tissue-equivalent ionization chamber. Both dose rate and pion stopping rate are given as a function of depth for beams of two different momenta spread. The energy deposition required per pion stop to fit the measured dose rate curves was calculated and found to be between 37 and 40 MeV. From the stopping rate measurements the depth-dose distribution of pion interaction dose (star-dose) and the dose due to the pion slowing down were evaluated. (8 refs).
The transverse spin structure of the pion at short distances
International Nuclear Information System (INIS)
Diehl, Markus; Szymanowski, Lech; Ecole Polytechnique, CNRS, Palaiseau; Paris-Sud Univ., CNRS, Orsay
2010-03-01
We study the form factors of the quark tensor currents in the pion at large squared momentum transfer Q 2 . It turns out that certain form factors can be evaluated using collinear factorization, whereas others receive important contributions from the end-point regions of the longitudinal quark momenta in the pion. We derive simple analytic expressions for the dominant terms at high Q 2 and illustrate them numerically. (orig.)
The transverse spin structure of the pion at short distances
Energy Technology Data Exchange (ETDEWEB)
Diehl, Markus, E-mail: mdiehl@mail.desy.d [Deutsches Elektronen-Synchroton DESY, 22603 Hamburg (Germany); Szymanowski, Lech [Soltan Institute for Nuclear Studies, Warsaw (Poland); Centre de Physique Theorique, Ecole Polytechnique, CNRS, 91128 Palaiseau (France); Laboratoire de Physique Theorique, Universite Paris-Sud, CNRS, 91405 Orsay (France)
2010-06-14
We study the form factors of the quark tensor currents in the pion at large squared momentum transfer Q{sup 2}. It turns out that certain form factors can be evaluated using collinear factorization, whereas others receive important contributions from the end-point regions of the longitudinal quark momenta in the pion. We derive simple analytic expressions for the dominant terms at high Q{sup 2} and illustrate them numerically.
The transverse spin structure of the pion at short distances
Energy Technology Data Exchange (ETDEWEB)
Diehl, Markus [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Szymanowski, Lech [Soltan Inst. for Nuclear Studies, Warsaw (Poland); Ecole Polytechnique, CNRS, Palaiseau (France). Centre de Physique Theorique; Paris-Sud Univ., CNRS, Orsay (France). Lab. de Physique Theorique
2010-03-15
We study the form factors of the quark tensor currents in the pion at large squared momentum transfer Q{sup 2}. It turns out that certain form factors can be evaluated using collinear factorization, whereas others receive important contributions from the end-point regions of the longitudinal quark momenta in the pion. We derive simple analytic expressions for the dominant terms at high Q{sup 2} and illustrate them numerically. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Yung, Kar Woo [California Inst. of Technology (CalTech), Pasadena, CA (United States)
1979-09-19
High transverse momentum ($P_T$) particles are thought to reflect the underlying parton (quark or gluon) mechanisms of hadron interactions. A particularly simple model by Feynman, Field and Fox (or FFF>, involves hard scattering of a pair of partons via gluon exchange (Quantum Chromodynamics or GCD) with subsequent fragmentation or the partons into hadrons. We present results from an experiment (E260 at Fermilab) on the production of Jets (groups of particles) and single charged particles, at both low and high $P_T$, in 200 Gev interactions. The experiment used a calorimeter triggered multiparticle spectrometer. Results are presented on the comparisons of cross sections and associated charged particle distributions for pion and proton beams and aluminium and hydrogen targets.
The pion: an enigma within the Standard Model
Energy Technology Data Exchange (ETDEWEB)
Horn, Tanja; Roberts, Craig D.
2016-05-27
Almost 50 years after the discovery of gluons & quarks, we are only just beginning to understand how QCD builds the basic bricks for nuclei: neutrons, protons, and the pions that bind them. QCD is characterised by two emergent phenomena: confinement & dynamical chiral symmetry breaking (DCSB). They are expressed with great force in the character of the pion. In turn, pion properties suggest that confinement & DCSB are closely connected. As both a Nambu-Goldstone boson and a quark-antiquark bound-state, the pion is unique in Nature. Developing an understanding of its properties is thus critical to revealing basic features of the Standard Model. We describe experimental progress in this direction, made using electromagnetic probes, highlighting both improvements in the precision of charged-pion form factor data, achieved in the past decade, and new results on the neutral-pion transition form factor. Both challenge existing notions of pion structure. We also provide a theoretical context for these empirical advances, first explaining how DCSB works to guarantee that the pion is unnaturally light; but also, nevertheless, ensures the pion is key to revealing the mechanisms that generate nearly all the mass of hadrons. Our discussion unifies the charged-pion elastic and neutral-pion transition form factors, and the pion's twist-2 parton distribution amplitude. It also indicates how studies of the charged-kaon form factor can provide significant contributions. Importantly, recent predictions for the large-$Q^2$ behaviour of the pion form factor can be tested by experiments planned at JLab 12. Those experiments will extend precise charged-pion form factor data to momenta that can potentially serve in validating factorisation theorems in QCD, exposing the transition between the nonperturbative and perturbative domains, and thereby reaching a goal that has long driven hadro-particle physics.
π-p→ωn reaction at momenta from 15 to 40 GeV/c
International Nuclear Information System (INIS)
Apel, W.D.; Augenstein, K.H.; Bertolucci, E.; Vincelli, M.L.; Donskov, S.V.; Inyakin, A.; Kachanov, V.A.; Quaglia, M.; Krasnokutsky, R.N.; Krueger, M.; Leder, G.; Lednev, A.A.; Mannelli, I.; Mikhailov, Y.V.; Mueller, H.; Prokoshkin, Y.D.; Pierazzini, G.M.; Sergiampietri, F.; Sigurdsson, G.; Scribano, A.; Schneider, H.; Shuvalov, R.S.
1980-01-01
Cross sections for the reaction π - p→ωn, ω→π 0 γ have been measured with good statistics at incident-pion momenta of 15, 20, 25, 30, and 40 GeV/c. The experiments were performed at the 70-GeV IHEP accelerator, using the NICE 648-channel hodoscopic spectrometer. The density matrix elements and the differential and integrated cross sections for the reaction have been determined. The unnatural-parity exchange contribution to the production of ω mesons in the state with helicity 1 is already insignificant at 15 GeV/c. With increasing Vertical BartVertical Bar the differential cross sections pass through a maximum at Vertical BartVertical Barapprox. =0.12 (GeV/c) 2 and then fall exponentially until Vertical BartVertical Barapprox. =0.7 (GeV/c) 2 ; at that point the curve bends sharply, the cross section falling off much less rapidly for larger values of Vertical BartVertical Bar
Electromagnetic form factors at large momenta from lattice QCD
Chambers, A. J.; Dragos, J.; Horsley, R.; Nakamura, Y.; Perlt, H.; Pleiter, D.; Rakow, P. E. L.; Schierholz, G.; Schiller, A.; Somfleth, K.; Stüben, H.; Young, R. D.; Zanotti, J. M.; Qcdsf/Ukqcd/Cssm Collaborations
2017-12-01
Accessing hadronic form factors at large momentum transfers has traditionally presented a challenge for lattice QCD simulations. Here, we demonstrate how a novel implementation of the Feynman-Hellmann method can be employed to calculate hadronic form factors in lattice QCD at momenta much higher than previously accessible. Our simulations are performed on a single set of gauge configurations with three flavors of degenerate mass quarks corresponding to mπ≈470 MeV . We are able to determine the electromagnetic form factors of the pion and nucleon up to approximately 6 GeV2 , with results for the ratio of the electric and magnetic form factors of the proton at our simulated quark mass agreeing well with experimental results.
Recoil momenta distributions in the double photoionization
International Nuclear Information System (INIS)
Amusia, M Ya; Liverts, E Z; Drukarev, E G; Mikhai, A I
2014-01-01
We calculate the distributions in recoil momenta for the high energy double photoionization of helium caused by quasifree mechanism. The distributions obtain local maxima at small values of the recoil momenta. This agrees with earlier predictions and recent experimental data. Angular correlations which reach the largest value for 'back-to-back' configuration of photoelectrons are also obtained.
Estimating hadron contamination of electron samples in Pb-Pb collisions at low momenta using ALICE
Energy Technology Data Exchange (ETDEWEB)
Brass, Martin [Physikalisches Institut, Universitaet Heidelberg (Germany); Collaboration: ALICE-Collaboration
2015-07-01
A Large Ion Collider Experiment at the LHC is exploring a new state of matter at high energy densities in Pb-Pb collisions. Electrons from heavy-flavor decays are interesting probes of the properties of this state, since charm and beauty quarks - produced in initial hard scatterings - experience the whole evolution of the state. Due to high multiplicities in Pb-Pb collisions and to the limited separation power of the ALICE Time-Of-Flight (TOF) detector between electrons and pions at momenta above 1 GeV/c, there is a large hadronic background in the observed electron samples. Furthermore a significant amount of protons, kaons and deuterons are misidentified by TOF and contaminate the electron sample, too. Many Heavy-Flavor-Electron analyses rely on a precise estimation of the contamination. The presented analysis uses measured energy loss distributions of the ALICE Time Projection Chamber as templates for a least squares fit routine to estimate the amount of hadronic background in the electron sample at momenta above 0.4 GeV/c. To describe the energy loss distributions of the misidentified particles, the measured distributions of particles which are identified by TOF are used. The energy loss distribution for pions is obtained using the ALICE Transition Radiation Detector which provides good separation between pions and electrons.
International Nuclear Information System (INIS)
Dicello, J.F.
1975-01-01
Negative pion beams are probably the most esoteric and most complicated type of radiation which has been suggested for use in clinical radiotherapy. Because of the limited availability of pion beams in the past, even to nuclear physicists, there exist relatively fewer basic data for this modality. Pion dosimetry is discussed
Energy Technology Data Exchange (ETDEWEB)
Walter, J.B.; Rebka, G.A. Jr.
1979-03-01
A subroutine, SCATPI, was written which calculates ..pi../sup +/p elastic differential cross sections for incident pion kinetic energies between 90 and 310 MeV for ..pi../sup -/p. The calculation is based upon the phase shift analysis of Carter, Bugg, and Carter, and is reliable to about 2% for ..pi../sup +/p and 3% for ..pi../sup -/p differential cross sections. SCATPI also calculates other scattering parameters for the ..pi..+-p systems. The calculations are compared with the measurements used in the phase shift analysis, and with selected recent measurements. The use of SCATPI is described. 14 figures, 4 tables.
Transverse and longitudinal angular momenta of light
Energy Technology Data Exchange (ETDEWEB)
Bliokh, Konstantin Y., E-mail: k.bliokh@gmail.com [Center for Emergent Matter Science, RIKEN, Wako-shi, Saitama 351-0198 (Japan); Nonlinear Physics Centre, RSPhysE, The Australian National University, Canberra, ACT 0200 (Australia); Nori, Franco [Center for Emergent Matter Science, RIKEN, Wako-shi, Saitama 351-0198 (Japan); Physics Department, University of Michigan, Ann Arbor, MI 48109-1040 (United States)
2015-08-26
We review basic physics and novel types of optical angular momentum. We start with a theoretical overview of momentum and angular momentum properties of generic optical fields, and discuss methods for their experimental measurements. In particular, we describe the well-known longitudinal (i.e., aligned with the mean momentum) spin and orbital angular momenta in polarized vortex beams. Then, we focus on the transverse (i.e., orthogonal to the mean momentum) spin and orbital angular momenta, which were recently actively discussed in theory and observed in experiments. First, the recently-discovered transverse spin angular momenta appear in various structured fields: evanescent waves, interference fields, and focused beams. We show that there are several kinds of transverse spin angular momentum, which differ strongly in their origins and physical properties. We describe extraordinary features of the transverse optical spins and overview recent experiments. In particular, the helicity-independent transverse spin inherent in edge evanescent waves offers robust spin–direction coupling at optical interfaces (the quantum spin Hall effect of light). Second, we overview the transverse orbital angular momenta of light, which can be both extrinsic and intrinsic. These two types of the transverse orbital angular momentum are produced by spatial shifts of the optical beams (e.g., in the spin Hall effect of light) and their Lorentz boosts, respectively. Our review is underpinned by a unified theory of the angular momentum of light based on the canonical momentum and spin densities, which avoids complications associated with the separation of spin and orbital angular momenta in the Poynting picture. It allows us to construct a comprehensive classification of all known optical angular momenta based on their key parameters and main physical properties.
International Nuclear Information System (INIS)
Beavis, D.; Fung, S.Y.; Gorn, W.; Keane, D.; Liu, Y.M.; Poe, R.T.; VanDalen, G.; Vient, M.
1984-01-01
Preliminary analysis of pion production in 1.2 GeV/nucleon Kr-RbBr collisions is presented. The negative pion multiplicity is consistent with a convolution of Poisson distributions and a freeze-out density between 1/3 and 1/2 normal nuclear density is extracted. Global negative pion kinematic variables are used to search for possible structure in the multi-pion emission. No evidence for structured emission or conservation constraints is found. Pion interferometry analysis gives a source radius of 5.4 +- 1.2 Fermi and a freeze-out density of .3 +- .2 times normal nuclear density. 10 refs., 5 figs
Relativistic description of directly interacting pions and nucleons
International Nuclear Information System (INIS)
Heller, L.
1976-01-01
The expected magnitudes of the leading relativistic effects on an off-energy-shell T matrix element are estimated using the Bakamjian--Thomas formulation of relativistic potential theory. For pion-nucleon scattering at medium energy, the two largest corrections are expected to result from the use of relativistic relative momenta rather than nonrelativistic values. The importance of additional terms depends upon the detailed behavior of the T matrix
Large-angle production of charged pions with 3-12.9 GeV/c incident protons on nuclear targets
Catanesi, M.G.; Edgecock, R.; Ellis, Malcolm; Soler, F.J.P.; Gossling, C.; Bunyatov, S.; Krasnoperov, A.; Popov, B.; Serdiouk, V.; Tereschenko, V.; Di Capua, E.; Vidal-Sitjes, G.; Artamonov, A.; Giani, S.; Gilardoni, S.; Gorbunov, P.; Grant, A.; Grossheim, A.; Ivanchenko, A.; Ivanchenko, V.; Kayis-Topaksu, A.; Panman, J.; Papadopoulos, I.; Tcherniaev, E.; Tsukerman, I.; Veenhof, R.; Wiebusch, C.; Zucchelli, P.; Blondel, A.; Borghi, S.; Morone, M.C.; Prior, G.; Schroeter, R.; Meurer, C.; Gastaldi, U.; Mills, G.B.; Graulich, J.S.; Gregoire, G.; Bonesini, M.; Ferri, F.; Kirsanov, M.; Bagulya, A.; Grichine, V.; Polukhina, N.; Palladino, V.; Coney, L.; Schmitz, D.; Barr, G.; De Santo, A.; Bobisut, F.; Gibin, D.; Guglielmi, A.; Mezzetto, M.; Dumarchez, J.; Dore, U.; Orestano, D.; Pastore, F.; Tonazzo, A.; Tortora, L.; Booth, C.; Howlett, L.; Skoro, G.; Bogomilov, M.; Chizhov, M.; Kolev, D.; Tsenov, R.; Piperov, Stefan; Temnikov, P.; Apollonio, M.; Chimenti, P.; Giannini, G.; Burguet-Castell, J.; Cervera-Villanueva, A.; Gomez-Cadenas, J.J.; Martin-Albo, J.; Novella, P.; Sorel, M.; Tornero, A.
2008-01-01
Measurements of the double-differential charged pion production cross-section in the range of momentum 100 MeV/c < p < 800 MeV/c and angle 0.35 < \\theta < 2.15 rad in proton-beryllium, proton-carbon, proton-aluminium, proton-copper, proton-tin, proton-tantalum and proton-lead collisions are presented. The data were taken with the large acceptance HARP detector in the T9 beam line of the CERN PS. The pions were produced by proton beams in a momentum range from 3 GeV/c to 12.9 GeV/c hitting a target with a thickness of 5% of a nuclear interaction length.
International Nuclear Information System (INIS)
Dumbrajs, O.
1981-01-01
The concept of the pion-nucleus coupling constants is discussed. Methods of their determination are reviewed. These include: forward dispersion relations, extrapolation of differential cross sections to the poles in the angular variable, analysis of data on electromagnetic form factors with the use of the PCAC and CVC hypotheses, pion photoproduction at threshold and low-energy theorems. Our present knowledge of the pion coupling to the He, Li, Be, C, N and O nuclei is summarized. (author)
AUTHOR|(SzGeCERN)663936; Dominik, Wojciech; Gaździck, Marek
2016-01-01
This thesis presents inclusive spectra of the negatively charged pions produced in inelastic proton-proton interactions measured at five beam momenta: 20, 31, 40, 80 and 158 GeV/c. The measurements were conducted in the NA61/SHINE experiment at CERN using a system of five Time Projection Chambers. The negatively charged pion spectra were calculated based on the negatively charged hadron spectra. Contribution of hadrons other than the primary pions was removed using EPOS simulations. The results were corrected for effects related to detection, acceptance, reconstruction efficiency and the analysis technique. Two-dimensional spectra were derived as a function of rapidity and transverse momentum or transverse mass. The spectra were parametrised by widths of the rapidity distributions, inverse slope parameters of the transverse mass distributions, mean transverse masses and the total pion multiplicities. The negatively charged pion spectra in proton-proton interactions belong to a broad NA61/SHINE programme of se...
International Nuclear Information System (INIS)
Dubnicka, S.; Martinovic, L.
1988-01-01
Using precise experimental information on the imaginary part of the pion form factor from e + e - → π + π - up to the inelastic threshold and QCD constraints for it in the range of momenta (m π 0 +m ω ) 2 < t < infinity, was investigated by means of a dispersion integral the reliability of individual electroproduction CEA and Cornell model-dependent pion form factor data points
Pion nucleus scattering lengths
International Nuclear Information System (INIS)
Huang, W.T.; Levinson, C.A.; Banerjee, M.K.
1971-09-01
Soft pion theory and the Fubini-Furlan mass dispersion relations have been used to analyze the pion nucleon scattering lengths and obtain a value for the sigma commutator term. With this value and using the same principles, scattering lengths have been predicted for nuclei with mass number ranging from 6 to 23. Agreement with experiment is very good. For those who believe in the Gell-Mann-Levy sigma model, the evaluation of the commutator yields the value 0.26(m/sub σ//m/sub π/) 2 for the sigma nucleon coupling constant. The large dispersive corrections for the isosymmetric case implies that the basic idea behind many of the soft pion calculations, namely, slow variation of matrix elements from the soft pion limit to the physical pion mass, is not correct. 11 refs., 1 fig., 3 tabs
International Nuclear Information System (INIS)
Ericson, T.E.O.
1978-01-01
The fleeting existence of pions inside nuclei is responsible for the modification of nucleon properties in β decay μ-capture, photo-processes, magnetic moments and the like. The physical situations in which the interaction of the pions is expected to be very close to that of real pions, but in which the binding effects will manifest themselves fully are here discussed. The effect of such binding is illustrated by the line-shape of an absorbing (pionic) atom. μ-capture at large energy transfers is discussed. (U.K.)
International Nuclear Information System (INIS)
Afnan, I.R.; Thomas, A.W.
1976-01-01
A method has been suggested for relating μ-capture in nuclei to pion absorption through partially conserved axial vector current hypothesis. The success of the method relies heavily on the knowledge of the pion absorption amplitude at a momentum transfer equal to the μ-meson mass. That is we need to know the pion absorption amplitude off the mass-shell. The simplest nucleus for which this suggestion can be examined is μ-capture in deuterium. The Koltum-Reitan model is used to determine the pion absorption amplitude off the mass shell. In particular the senstivity of this off-mass-shell extrapolution to details of the N-N interaction is studied. (author)
Measurement of the 3He(e,e'p)pn reaction at high missing energies and momenta
Energy Technology Data Exchange (ETDEWEB)
F. Benmokhtar; M. M. Rvachev; E. Penel-Nottaris
2004-09-01
Results of the Jefferson Lab Hall A quasielastic 3He(e,e'p)pn measurements are presented. These measurements were performed at fixed transferred momentum and energy, q = 1502 MeV/c and omega = 840 MeV, respectively, for missing momenta {+-} up to 1 GeV/c and missing energies in the continuum region, up to pion threshold; this kinematic coverage is much more extensive than that of any previous experiment. The cross section data are presented along with the effective momentum density distribution and compared to theoretical models.
Nuclear scissors modes and hidden angular momenta
Energy Technology Data Exchange (ETDEWEB)
Balbutsev, E. B., E-mail: balbuts@theor.jinr.ru; Molodtsova, I. V. [Joint Institute for Nuclear Research (Russian Federation); Schuck, P. [Université Paris-Sud, Institut de Physique Nucléaire, IN2P3–CNRS (France)
2017-01-15
The coupled dynamics of low-lying modes and various giant resonances are studied with the help of the Wigner Function Moments method generalized to take into account spin degrees of freedom and pair correlations simultaneously. The method is based on Time-Dependent Hartree–Fock–Bogoliubov equations. The model of the harmonic oscillator including spin–orbit potential plus quadrupole–quadrupole and spin–spin interactions is considered. New low-lying spin-dependent modes are analyzed. Special attention is paid to the scissors modes. A new source of nuclear magnetism, connected with counter-rotation of spins up and down around the symmetry axis (hidden angular momenta), is discovered. Its inclusion into the theory allows one to improve substantially the agreement with experimental data in the description of energies and transition probabilities of scissors modes.
News on mean pion multiplicity from NA61/SHINE
Naskręt, Michał
2018-02-01
NA61/SHINE is a large acceptance fixed target experiment at the CERN SPS which studies final hadronic states in interactions between various particles and nuclei [1]. The main topic of this contribution are preliminary results for mean negatively charged pion multiplicities 〈π-〉 from central Ar+Sc and Be+Be collisions. The data were taken recently by the NA61/SHINE collaboration for a wide range of beam momenta. Measured rapidity distributions were extrapolated to unmeasured regions to obtain total multiplicities 〈π-〉 A new scheme to calculate the mean number of wounded nucleons 〈W〉 utilizing the EPOS MC model is described. Using data from other experiments, a comparison of for different collisions and beam momenta is discussed.
Transverse momentum dependence of semi-inclusive pion production
Energy Technology Data Exchange (ETDEWEB)
Hamlet Mkrtchyan; Peter Bosted
2007-09-19
Cross sections for semi-inclusive electroproduction of charged pions ($\\pi^{\\pm}$) from both proton and deuteron targets were measured for $0.2<0.5$, $2<4$ GeV$^2$, $0.3<1$, and $P_t^2<0.2$ GeV$^2$. We find the azimuthal dependence to be small and consistent with zero, for $P_t<0.1$ GeV. In the context of a simple fit, the initial transverse momenta of $d$ quarks tends to be larger than for $u$ quarks, while the transverse momentum width of the favored fragmentation function is slightly larger than that of the unfavored function.
Catanesi, M.G.; Ellis, Malcolm; Robbins, S.; Soler, F.J.P.; Gossling, C.; Bunyatov, S.; Krasnoperov, A.; Popov, B.; Serdiouk, V.; Tereschenko, V.; Di Capua, E.; Vidal-Sitjes, G.; Artamonov, A.; Arce, P.; Giani, S.; Gilardoni, S.; Gorbunov, P.; Grant, A.; Grossheim, A.; Gruber, P.; Ivanchenko, V.; Kayis-Topaksu, A.; Panman, J.; Papadopoulos, I.; Pasternak, J.; Tcherniaev, E.; Tsukerman, I.; Veenhof, R.; Wiebusch, C.; Zucchelli, P.; Blondel, A.; Borghi, S.; Campanelli, M.; Morone, M.C.; Prior, G.; Schroeter, R.; Engel, R.; Meurer, C.; Kato, I.; Gastaldi, U.; Mills, G.B.; Graulich, J.S.; Gregoire, G.; Bonesini, M.; Ferri, F.; Paganoni, M.; Paleari, F.; Kirsanov, M.; Bagulya, A.; Grichine, V.; Polukhina, M.; Palladino, V.; Coney, L.; Schmitz, D.; Barr, G.; De Santo, A.; Pattison, C.; Zuber, K.; Bobisut, F.; Gibin, D.; Guglielmi, A.; Mezzetto, M.; Dumarchez, J.; Vannucci, F.; Dore, U.; Orestano, D.; Pastore, F.; Tonazzo, A.; Tortora, L.; Booth, C.; Buttar, C.; Hodgson, P.; howlett, L.; Bogomilov, M.; Chizhov, M.; Kolev, D.; Tsenov, R.; Piperov, Stefan; Temnikov, P.; Apollonio, M.; Chimenti, P.; Giannini, G.; Santin, G.; Burguet-Castell, J.; Cervera-Villanueva, A.; Gomez-Cadenas, J.J.; Martin-Albo, J.; Novella, P.; Sorel, M.; Tornero, A.
2008-01-01
A measurement of the double-differential $\\pi^{\\pm}$ production cross-section in proton--carbon, proton--copper and proton--tin collisions in the range of pion momentum $100 \\MeVc \\leq p < 800 \\MeVc$ and angle $0.35 \\rad \\le \\theta <2.15 \\rad$ is presented. The data were taken with the HARP detector in the T9 beam line of the CERN PS. The pions were produced by proton beams in a momentum range from 3 \\GeVc to 12 \\GeVc hitting a target with a thickness of 5% of a nuclear interaction length. The tracking and identification of the produced particles was done using a small-radius cylindrical time projection chamber (TPC) placed in a solenoidal magnet. An elaborate system of detectors in the beam line ensured the identification of the incident particles. Results are shown for the double-differential cross-sections at four incident proton beam momenta (3 \\GeVc, 5 \\GeVc, 8 \\GeVc and 12 \\GeVc).
Influence of the nuclear symmetry energy on the collective flows of charged pions
Gao, Yuan; Yong, Gao-Chan; Zhang, Lei; Zuo, Wei
2018-01-01
Based on the isospin-dependent Boltzmann-Uehling-Uhlenbeck (IBUU) transport model, we studied charged pion transverse and elliptic flows in semicentral 197Au+197Au collisions at 600 MeV/nucleon. It is found that π+-π- differential transverse flow and the difference of π+ and π- transverse flows almost show no effects of the symmetry energy. Their corresponding elliptic flows are largely affected by the symmetry energy, especially at high transverse momenta. The isospin-dependent pion elliptic flow at high transverse momenta thus provides a promising way to probe the high-density behavior of the symmetry energy in heavy-ion collisions at the Facility for Antiproton and Ion Research (FAIR) at GSI, Darmstadt or at the Cooling Storage Ring (CSR) at HIRFL, Lanzhou.
International Nuclear Information System (INIS)
Andresen, A.; Krueger, J.; Tsurugai, T.; Youngman, C.; Behrens, U.; Holm, U.; Wick, K.; Bamberger, A.; Schaecke, D.; Crittenden, J.; Kraemer, M.; Caldwell, A.; Sippach, W.; Dawson, J.; Engelen, J.; Kooijman, P.; Straver, J.; Tiecke, H.; Gilkinson, D.; Hanna, D.; Mitchell, J.; Patel, P.; Hamatsu, R.; Hervas, L.; Fuertjes, A.; Klanner, R.; Koetz, U.; Malecki, P.; Rohde, M.; Ros, E.; Vogel, W.; Levman, G.; Martin, J.; Romanowski, T.
1990-01-01
We have exposed a sandwich calorimeter, consisting of 3.3 mm thick uranium plates interleaved with 2.6 mm thick scintillator tiles, to positive and negative electrons and pions and to protons in the momentum range of 0.5 to 10 GeV/c. We find that e/h is about 1 above 3 GeV/c, but decreases significantly for lower momenta. This ratio is the same for positive and negative pions and also for pions and protons of the same kinetic energy. (orig.)
1992-01-01
The real particles produced in the decay of a positive pion can be seen in this image from a streamer chamber. Streamer chambers consist of a gas chamber through which a strong pulsed electric field is passed, creating sparks as a charged particle passes through it. A magnetic field is added to cause the decay products to follow curved paths so that their charge and momentum can be measured.
Pion polarizabilities measurement at COMPASS
Guskov, Alexey
2008-01-01
The electromagnetic structure of pions is probed in $\\pi^{−}+(A,Z) \\rightarrow\\pi^{−}+(A,Z)+\\gamma$ Compton scattering in inverse kinematics (Primakoff reaction) and described by the electric ($\\bar{\\alpha_{\\pi}}$) and the magnetic ($\\bar{\\beta_{\\pi}}$) polarizabilities that depend on the rigidity of pion’s internal structure as a composite particle. Values for pion polarizabilities can be extracted from the comparison of the differential cross section for scattering of pointlike pions with the measured cross section. The pion polarizability measurement was performed with a $\\pi^{-}$ beam of 190 GeV. The high beam intensity, the good spectrometer resolution, the high rate capability, the high acceptance and the possibility to use pion and muon beams, unique to the COMPASS experiment, provide the tools to measure precisely the pion polarizabilities in the Primakoff reaction.
Pion Polarizability Status Report (2017)
Moinester, Murray
2017-01-01
The electric ${\\alpha}_{\\pi}$ and magnetic $\\beta_{\\pi}$ charged pion Compton polarizabilities are of fundamental interest in the low-energy sector of quantum chromodynamics (QCD).They are directly linked to the phenomenon of spontaneously broken chiral symmetry within QCD and to the dynamics of the pion-photon interaction.The combination (${\\alpha}_{\\pi}-\\beta_{\\pi}$) was measured by:(1) CERN COMPASS via radiative pion Primakoff scattering (Bremsstrahlung) in the nuclear Coulomb field, ${\\pi...
Exclusive electroproduction of pion pairs
International Nuclear Information System (INIS)
Warkentin, N.; Schaefer, A.; Diehl, M.; Ivanov, D. Yu.
2007-01-01
We investigate electroproduction of pion pairs on the nucleon in the framework of QCD factorization for hard exclusive processes. We extend previous analyses by taking the hard-scattering coefficients at next-to-leading order in α s . The dynamics of the produced pion pair is described by two-pion distribution amplitudes, for which we perform a detailed theoretical and phenomenological analysis. In particular, we obtain constraints on these quantities by comparing our results with measurements of angular observables that are sensitive to the interference between two-pion production in the isoscalar and isovector channels. (orig.)
Chefdeville, M.; Repond, J.; Schlereth, J.; Xia, L.; Eigen, G.; Marshall, J.S.; Thomson, M.A.; Ward, D.R.; Alipour Tehrani, N.; Apostolakis, J.; Dannheim, D.; Elsener, K.; Folger, G.; Grefe, C.; Ivantchenko, V.; Killenberg, M.; Klempt, W.; van der Kraaij, E.; Linssen, L.; Lucaci-Timoce, A.-I.; Münnich, A.; Poss, S.; Ribon, A.; Roloff, P.; Sailer, A.; Schlatter, D.; Sicking, E.; Strube, J.; Uzhinskiy, V.; Chang, S.; Khan, A.; Kim, D.H.; Kong, D.J.; Oh, Y.D.; Blazey, G.C.; Dyshkant, A.; Francis, K.; Zutshi, V.; Giraud, J.; Grondin, D.; Hostachy, J.-Y.; Brianne, E.; Cornett, U.; David, D.; Falley, G.; Gadow, K.; Göttlicher, P.; Günter, C.; Hartbrich, O.; Hermberg, B.; Irles, A.; Karstensen, S.; Krivan, F.; Krüger, K.; Kvasnicka, J.; Lu, S.; Lutz, B.; Morozov, S.; Morgunov, V.; Neubüser, C.; Provenza, A.; Reinecke, M.; Sefkow, F.; Smirnov, P.; Terwort, M.; Tran, H.L.; Vargas-Trevino, A.; Garutti, E.; Laurien, S.; Matysek, M.; Ramilli, M.; Schröder, S.; Briggl, K.; Eckert, P.; Harion, T.; Munwes, Y.; Schultz-Coulon, H. -Ch.; Shen, W.; Stamen, R.; Bilki, B.; Onel, Y.; Kawagoe, K.; Hirai, H.; Sudo, Y.; Suehara, T.; Sumida, H.; Takada, S.; Tomita, T.; Yoshioka, T.; Wing, M.; Calvo Alamillo, E.; Fouz, M. -C.; Marin, J.; Puerta-Pelayo, J.; Verdugo, A.; Bobchenko, B.; Chadeeva, M.; Danilov, M.; Markin, O.; Mizuk, R.; Novikov, E.; Rusinov, V.; Tarkovsky, E.; Kirikova, N.; Kozlov, V.; Smirnov, P.; Soloviev, Y.; Besson, D.; Buzhan, P.; Popova, E.; Gabriel, M.; Kiesling, C.; van der Kolk, N.; Seidel, K.; Simon, F.; Soldner, C.; Szalay, M.; Tesar, M.; Weuste, L.; Amjad, M.S.; Bonis, J.; Cornebise, P.; Richard, F.; Pöschl, R.; Rouëné, J.; Thiebault, A.; Anduze, M.; Balagura, V.; Boudry, V.; Brient, J-C.; Cizel, J-B.; Cornat, R.; Frotin, M.; Gastaldi, F.; Haddad, Y.; Magniette, F.; Nanni, J.; Pavy, S.; Rubio-Roy, M.; Shpak, K.; Tran, T.H.; Videau, H.; Yu, D.; Callier, S.; Conforti di Lorenzo, S.; Dulucq, F.; Fleury, J.; Martin-Chassard, G.; de la Taille, Ch.; Raux, L.; Seguin-Moreau, N.; Cvach, J.; Gallus, P.; Havranek, M.; Janata, M.; Kovalcuk, M.; Lednicky, D.; Marcisovsky, M.; Polak, I.; Popule, J.; Tomasek, L.; Tomasek, M.; Ruzicka, P.; Sicho, P.; Smolik, J.; Vrba, V.; Zalesak, J.; Ieki, S.; Kamiya, Y.; Ootani, W.; Shibata, N.; Chen, S.; Jeans, D.; Komamiya, S.; Kozakai, C.; Nakanishi, H.; Götze, M.; Sauer, J.; Weber, S.; Zeitnitz, C.
2015-12-10
We present a study of showers initiated by electrons, pions, kaons, and protons with momenta from 15 GeV to 150 GeV in the highly granular CALICE analogue scintillator-tungsten hadronic calorimeter. The data were recorded at the CERN Super Proton Synchrotron in 2011. The analysis includes measurements of the calorimeter response to each particle type as well as measurements of the energy resolution and studies of the longitudinal and radial shower development for selected particles. The results are compared to Geant4 simulations (version 9.6.p02). In the study of the energy resolution we include previously published data with beam momenta from 1 GeV to 10 GeV recorded at the CERN Proton Synchrotron in 2010.
Angelopoulos, Angelos; Aslanides, Elie; Backenstoss, Gerhard; Bargassa, P; Behnke, O; Benelli, A; Bertin, V; Blanc, F; Bloch, P; Carlson, P J; Carroll, M; Carvalho, J; Cawley, E; Charalambous, S; Chardin, G; Chertok, M B; Cody, A; Danielsson, M; Dejardin, M; Derré, J; Ealet, A; Eleftheriadis, C; Evangelou, I; Faravel, L; Ferreira-Marques, R; Fetscher, W; Fidecaro, Maria; Filipcic, A; Francis, D; Fry, J; Gabathuler, Erwin; Gamet, R; Garreta, D; Gerber, H J; Go, A; Haselden, A; Hayman, P J; Henry-Coüannier, F; Hollander, R W; Hubert, E; Jon-And, K; Kettle, P R; Kokkas, P; Kreuger, R; Le Gac, R; Leimgruber, F; Liolios, A; Machado, E; Mandic, I; Manthos, N; Marel, Gérard; Mikuz, M; Miller, J; Montanet, François; Müller, A; Nakada, Tatsuya; Pagels, B; Papadopoulos, I M; Pavlopoulos, P; Pinto da Cunha, J; Policarpo, Armando; Polivka, G; Rickenbach, R; Roberts, B L; Ruf, T; Sakelliou, L; Sanders, P; Schäfer, M; Schaller, L A; Schietinger, T; Schopper, A; Soares, A; Tauscher, Ludwig; Thibault, C; Touchard, F; Touramanis, C; Triantis, F A; Van Beveren, E; van Eijk, C W E; Vlachos, S; Weber, P; Wigger, O; Wolter, M; Yéche, C; Zavrtanik, D; Zimmerman, D; Locher, M P; Markushin, V E
1998-01-01
We study $\\pi\\pi$ correlations in the exclusive reaction $\\ppb \\to 2\\pi^+2\\pi^-$ at rest measured by the CPLEAR experiment. Avoiding the introduction of an arbitrary reference sample, we analyse differential distributions for equal charge pion pairs removing the phase-space factor event by event. A peak at small relative momenta is most pronounced for large total momentum of the pair. The physical implications of bosonic symmetrization for the properties of the pion source, in particular its radius, are briefly discussed. The two extremes considered are the chaotic Hanbury-Brown--Twiss mechanism and the coherent Skyrmion model.
Hot nuclei: high temperatures, high angular momenta
International Nuclear Information System (INIS)
Guerreau, D.
1991-01-01
A review is made of the present status concerning the production of hot nuclei above 5 MeV temperature, concentrating mainly on the possible experimental evidences for the attainment of a critical temperature, on the existence of dynamical limitations to the energy deposition and on the experimental signatures for the formation of hot spinning nuclei. The data strongly suggest a nuclear disassembly in collisions involving very heavy ions at moderate incident velocities. Furthermore, hot nuclei seem to be quite stable against rotation on a short time scale. (author) 26 refs.; 12 figs
Pions from and about heavy ions
Energy Technology Data Exchange (ETDEWEB)
Rasmussen, J.O.
1982-09-01
A review is presented of the possibilities of pion production with heavy ion reactions. Major headings include: pion thermometry; hills and valleys in pion spectra; pionic orbits of nuclear size; pion confinement in the fireball; anomalons; and Schroedinger equation solutions for pionic atoms. 47 references, 9 figures. (GHT)
Pion polarizabilities measurement at COMPASS
Guskov, Alexey
2008-01-01
The electromagnetic structure of pions is probed in $\\pi^{−} + (A,Z)\\rightarrow\\pi^{−} + (A,Z) +\\gamma$ Compton scattering in inverse kinematics (Primakoff reaction) and described by the electric $(\\bar{\\alpha_{\\pi}})$ and the magnetic $(\\bar{\\beta_{\\pi}})$ polarizabilities that depend on the rigidity of pion’s internal structure as a composite particle. Values for pion polarizabilities can be extracted from the comparison of the differential cross section for scattering of pointlike pions with the measured cross section. The pion polarizability measurement was performed with $a \\pi^{−}$ beam of 190 GeV. The high beam intensity, the good spectrometer resolution, the high rate capability, the high acceptance and the possibility to use pion and muon beams, unique to the COMPASS experiment, provide the tools to measure precisely the pion polarizabilities in the Primakoff reaction. The preliminary result for pion polarizabilities under the assumption of $\\bar{\\alpha_{\\pi}} + \\bar{\\beta_{\\pi}} =$ 0 is $\\ba...
International Nuclear Information System (INIS)
Chanfray, G.
1996-07-01
We discuss various aspects of pion physics in the nuclear medium. We first study s-wave pion-nucleus interaction in connection with chiral symmetry restoration and quark condensate in the nuclear medium. We then address the question of p-wave pion-nucleus interaction and collective pionic modes in nuclei and draw the consequences for in medium ππ correlations especially in the scalar-isoscalar channel. We finally discuss the modification of the rho meson mass spectrum at finite density and/or temperature in connection with relativistic heavy ion collisions
Energy Technology Data Exchange (ETDEWEB)
Ryong Ji, C.; Pang, A.; Szczepaniak, A. [North Carolina State Univ., Raleigh, NC (United States)
1994-04-01
It is pointed out that the correct criterion to define the legal PQCD contribution to the exclusive processes in the lightcone perturbative expansion should be based on the large off-shellness of the lightcone energy in the intermediate states. In the lightcone perturbative QCD calculation of the pion form factor, the authors find that the legal PQCD contribution defined by the lightcone energy cut saturates in the smaller Q{sup 2} region compared to that defined by the gluon four-momentum square cut. This is due to the contribution by the highly off-energy-shell gluons in the end point regions of the phase space, indicating that the gluon four-momentum-square cut may have cut too much to define the legal PQCD.
Energy Technology Data Exchange (ETDEWEB)
Haiyan Gao, Wei Chen
2009-12-01
We extracted the differential cross section for the gn --> pi-p process from a deuterium target using the CLAS detector at Jefferson Lab in Hall B for photon energies between 1.0 and 3.5 GeV and pion center-of-mass (c.m.) angles (theta c.m.) between 50 deg. and 115 deg. We confirm a previous indication of a broad enhancement around a c.m. energy (sqrt s) of 2.1 GeV at theta c.m. =90 deg. in the scaled differential cross section, s^7 ds/dt and a rapid fall-off in a center-of-mass energy region of about 400 MeV following the enhancement. Our data show an angular dependence of this enhancement as the suggested scaling region is approached for theta c.m. from 70 deg. to 10 deg.
Improved pion pion scattering amplitude from dispersion relation formalism
International Nuclear Information System (INIS)
Cavalcante, I.P.; Coutinho, Y.A.; Borges, J. Sa
2005-01-01
Pion-pion scattering amplitude is obtained from Chiral Perturbation Theory at one- and two-loop approximations. Dispersion relation formalism provides a more economic method, which was proved to reproduce the analytical structure of that amplitude at both approximation levels. This work extends the use of the formalism in order to compute further unitarity corrections to partial waves, including the D-wave amplitude. (author)
Shape of Pion Distribution Amplitude
Energy Technology Data Exchange (ETDEWEB)
Radyushkin, Anatoly
2009-11-01
A scenario is investigated in which the leading-twist pion distribution amplitude $\\varphi_\\pi (x)$ is approximated by the pion decay constant $f_\\pi$ for all essential values of the light-cone fraction $x$. A model for the light-front wave function $\\Psi (x, k_\\perp)$ is proposed that produces such a distribution amplitude and has a rapidly decreasing (exponential for definiteness) dependence on the light-front energy combination $ k_\\perp^2/x(1-x)$. It is shown that this model easily reproduces the fit of recent large-$Q^2$ BaBar data on the photon-pion transition form factor. Some aspects of scenario with flat pion distribution amplitude are discussed.
Catanesi, M.G.; Edgecock, R.; Ellis, Malcolm; Soler, F.J.P.; Gossling, C.; Bunyatov, S.; Krasnoperov, A.; Popov, B.; Serdiouk, V.; Tereschenko, V.; Di Capua, E.; Vidal-Sitjes, G.; Artamonov, A.; Giani, S.; Gilardoni, S.; Gorbunov, P.; Grant, A.; Grossheim, A.; Ivanchenko, V.; Kayis-Topaksu, A.; Panman, J.; Papadopoulos, I.; Tcherniaev, E.; Tsukerman, I.; Veenhof, R.; Wiebusch, C.; Zucchelli, P.; Blondel, A.; Borghi, S.; Morone, M.C.; Prior, G.; Schroeter, R.; Meurer, C.; Gastaldi, U.; Mills, G.B.; Graulich, J.S.; Gregoire, G.; Bonesini, M.; Ferri, F.; Kirsanov, M.; Bagulya, A.; Grichine, V.; Polukhina, N.; Palladino, V.; Coney, L.; Schmitz, D.; Barr, G.; De Santo, A.; Bobisut, F.; Gibin, D.; Guglielmi, A.; Mezzetto, M.; Dumarchez, J.; Dore, U.; Orestano, D.; Pastore, F.; Tonazzo, A.; Tortora, L.; Booth, C.; Howlett, L.; Bogomilov, M.; Chizhov, M.; Kolev, D.; Tsenov, R.; Piperov, Stefan; Temnikov, P.; Apollonio, M.; Chimenti, P.; Giannini, G.; Burguet-Castell, J.; Cervera-Villanueva, A.; Gomez-Cadenas, J.J.; Martin-Albo, J.; Novella, P.; Sorel, M.; CERN. Geneva
2008-01-01
Measurements of the double-differential $\\pi^{\\pm}$ production cross-section in the range of momentum $100 \\MeVc \\leq p < 800 \\MeVc$ and angle $0.35 \\rad \\leq \\theta < 2.15 \\rad$ in proton--beryllium, proton--aluminium and proton--lead collisions are presented. The data were taken with the HARP detector in the T9 beam line of the CERN PS. The pions were produced by proton beams in a momentum range from 3 \\GeVc to 12.9 \\GeVc hitting a target with a thickness of 5% of a nuclear interaction length. The tracking and identification of the produced particles was performed using a small-radius cylindrical time projection chamber (TPC) placed inside a solenoidal magnet. Incident particles were identified by an elaborate system of beam detectors. Results are obtained for the double-differential cross-sections at six incident proton beam momenta (3 \\GeVc, 5 \\GeVc, 8 \\GeVc, 8.9 \\GeVc (Be only), 12 \\GeVc and 12.9 \\GeVc (Al only)) and compared to previously available data.
Neutral pion electroproduction off light nuclei in chiral perturbation theory
International Nuclear Information System (INIS)
Lenkewitz, Mark
2013-01-01
Threshold pion electroproduction on tri-nucleon systems is investigated in the framework of baryon Chiral Perturbation Theory (ChPT) at next-to-leading one-loop order O(q 4 ) in the chiral expansion. To this order in small momenta, the production operator is a sum of one- and two-nucleon terms. While the one-nucleon terms resemble the impulse approximation, the two-nucleon contributions represent corrections due to the relevant nuclear interactions, e.g. pion-exchange interactions, which prove to be dominant, and due to recoil effects of the participating nucleons, which appear to be negligible. We calculate the expectation value of the production operator using chiral wave functions in a three-dimensional approach without partial wave expansion. The resulting integrals are evaluated using adaptive Monte Carlo integration, the VEGAS algorithm of Lepage. We obtain results for the threshold production multipoles E 0+ and L 0+ on 3 He and 3 H and comment on the sensitivity to the fundamental neutron amplitude E 0+ π 0 n . 3 He appears to be a particularly promising target to extract information about the neutron amplitude. This idea is usually invoked for spin-dependent quantities since the 3 He wave function is strongly dominated by the principal S-state component which suggests that its spin is largely driven by the one of the neutron.
Microdosimetry of negative pions
International Nuclear Information System (INIS)
Amols, H.I.; Dicello, J.F.; Lane, T.F.
1976-01-01
The radiation quality of negative and positive pions of initial momentum 168MeV/c has been determined at eight different depths in a liquid phantom. The measurements were made with a 2.5cm diameter spherical proportional counter with Shonka A-150 neutron tissue equivalent plastic walls. The gas pressure in the sensitive volume was chosen to stimulate a diameter of 2μm in unit density material. Dose distributions as a function of lineal energy change slowly in the entrance and plateau regions with a dose mean lineal energy of 6-8keV/μm. Less than 3% of the dose is delivered in excess of 50keV/μm in this region. In the Bragg peak region the distributions change rapidly as a function of depth with the dose mean lineal energy increasing to 38keV/μm at the peak and to 57keV/μm just beyond the peak. On the basis of these microdosimetric data predictions of RBE and OER have been made with the use of both the theory of dual radiation action and also the delta ray theory of cell survival. The former has been used to predict biological response at low doses and the latter at high doses. A comparison is made between the two theories at intermediate doses. The results of these calculations are not inconsistant with recent biological data
Electroweak corrections to hadronic photon production at large transverse momenta
International Nuclear Information System (INIS)
Kuehn, Johann H.; Kulesza, Anna; Pozzorini, Stefano; Schulze, Markus
2006-01-01
We study the impact of electroweak radiative corrections on direct production of photons with high transverse momenta at hadron colliders. Analytic results for the weak one-loop corrections to the parton scattering reaction q-bar q→γg and its crossed variants are presented. For the high-energy region, where the corrections are strongly enhanced by logarithms of s-circumflex /M W 2 , we derive simple asymptotic expressions which approximate the exact one-loop results with high precision. The dominant two-loop electroweak contributions are also calculated. Numerical results are presented for the LHC and the Tevatron. The corrections are negative and their size increases with transverse momentum. For the LHC, where transverse momenta of 2 TeV or more can be reached, the size of the one- and two-loop effects amounts up to -17% and +3%, respectively. At the Tevatron, with transverse momenta up to 400 GeV, the one-loop corrections do not exceed -4% and the two-loop effects are negligible. Finally we compare the cross sections for hadronic production of photons and Z bosons and find that the electroweak corrections have an important impact on their ratio
Rho meson self-energy and dielectron emissivity in an isospin-asymmetric pion medium
International Nuclear Information System (INIS)
Gulamov, T.I.; Titov, A.I.; Forschungszentrum Rossendorf e.V.; Kaempfer, B.; Technische Univ., Dresden
1995-06-01
The ρ meson self-energy in an isospin asymmetric pion gas at finite temperature and charged-pion chemical potential is evaluated. We utilize a conventional effective π-ρ Lagrangian and the functional integral representation of the partition function in the second order in the ρππ coupling constant. We analyze the gauge invariant rho meson polarization operator and its dependence on the invariant mass M and spatial momentum vertical stroke pvertical stroke of the ρ meson. The pole positions and the values of the imaginary parts of the self-energy for different polarization states have different functional dependences on M and vertical stroke pvertical stroke . The corresponding dielectron rate (calculated from the imaginary part of the polarization operators) shows a distinctive asymmetry when the momentum t=p + -p - is perpendicular or parallel to p, where p ± are the momenta of the electron pair. (orig.)
Power correction to the asymptotics of the pion electromagnetic form factor
International Nuclear Information System (INIS)
Geshkenbein, B.V.; Terentyev, M.V.
1982-01-01
The contribution of the power correction approximately (μ 2 /Q 2 ) 2 enhanced by the factor approximately μ 2 /anti m 2 , to the pion form factor (FF) is calculated (here μ is the pion mass, anti m=1/2(msub(u)+msub(α)) is the mean value of the u- and d-quark masses, Q 2 =-(p-p') 2 > 0, where p, p' are meson momenta at initial and final state. It is shown that the only source of large corrections is due to the contribution of the local pseudoscalar current. The main (approximately 1/Q 2 ) asymptotics of FF associated with the axial current contribution, is derived. The contribution (approximately 1/Q 4 ) of the pseudoscalar current is calculated
ρ-meson self-energy and dielectron emissivity in an isospin-asymmetric pion medium
International Nuclear Information System (INIS)
Titov, A.I.; Gulamov, T.I.; Kaempfer, B.
1996-01-01
The ρ-meson self-energy in an isospin-asymmetric pion gas at finite temperature and charged-pion chemical potential is evaluated. We utilize a conventional effective π-ρ Lagrangian and the functional integral representation of the partition function in the second order in the ρππ coupling constant. We analyze the ρ-meson polarization operator and its dependence on the invariant mass M and spatial momentum parallel p parallel of the ρ meson. The pole positions and the values of the imaginary parts of the self-energy for different polarization states have different functional dependences on M and parallel p parallel. The corresponding dielectron rate (calculated from the imaginary part of the in-medium ρ-meson propagator) shows a distinctive asymmetry when the momentum t=p + -p - is perpendicular or parallel to p, where p ± are the e ± momenta of the electron pair. copyright 1996 The American Physical Society
Norbury, J. W.; Cucinotta, F. A.; Deutchman, P. A.; Townsend, L. W.
1985-01-01
A coherent isobar formalism is employed to model subthreshold production of neutral pions in carbon-carbon collisions at energies below 100 MeV/nucleon. No arbitrary scale factors or adjustable free parameters are used in calculation of the Lorentz-invariant cross sections for pion production in the projectile, which produces an excited state that goes to M1 resonance in the target by conservation of spin and isospin. Pion production is also modeled for the projectile, which also reaches M1 resonance. The overall pion spectral distribution in the center of mass system is then integrated over the energy range 35-84 MeV/nucleon. The results expose an energy loss in the incident ions, as observed experimentally, and indicate that an isobar mechanism is responsible for higher energy pion production. Lower energy pions are a result of thermal processes.
Brown, Laurie Mark; Dresden, Max; Hoddeson, Lillian
2009-01-01
Part I. Introduction; 1. Pions to quarks: particle physics in the 1950s Laurie M Brown, Max Dresden and Lillian Hoddeson; 2. Particle physics in the early 1950s Chen Ning Yang; 3. An historian's interest in particle physics J. L. Heilbron; Part II. Particle discoveries in cosmic rays; 4. Cosmic-ray cloud-chamber contributions to the discovery of the strange particles in the decade 1947-1957 George D. Rochester; 5. Cosmic-ray work with emulsions in the 1940s and 1950s Donald H. Perkins; Part III. High-energy nuclear physics; Learning about nucleon resonances with pion photoproduction Robert L. Walker; 7. A personal view of nucleon structure as revealed by electron scattering Robert Hofstadter; 8. Comments on electromagnetic form factors of the nucleon Robert G. Sachs and Kameshwar C. Wali; Part IV. The new laboratory; 9. The making of an accelerator physicist Matthew Sands; 10. Accelerator design and construction in the 1950s John P. Blewett; 11. Early history of the Cosmotron and AGS Ernest D. Courant; 12. Panel on accelerators and detectors in the 1950s Lawrence W. Jones, Luis W. Alvarez, Ugo Amaldi, Robert Hofstadter, Donald W. Kerst, Robert R. Wilson; 13. Accelerators and the Midwestern Universities Research Association in the 1950s Donald W. Kerst; 14. Bubbles, sparks and the postwar laboratory Peter Galison; 15. Development of the discharge (spark) chamber in Japan in the 1950s Shuji Fukui; 16. Early work at the Bevatron: a personal account Gerson Goldhaber; 17. The discovery of the antiproton Owen Chamberlain; 18. On the antiproton discovery Oreste Piccioni; Part V. The Strange Particles; 19. The hydrogen bubble chamber and the strange resonances Luis W. Alvarez; 20. A particular view of particle physics in the fifties Jack Steinberger; 21. Strange particles William Chinowsky; 22. Strange particles: production by Cosmotron beams as observed in diffusion cloud chambers William B. Fowler; 23. From the 1940s into the 1950s Abraham Pais; Part VI. Detection of the
Quark bag coupling to finite size pions
International Nuclear Information System (INIS)
De Kam, J.; Pirner, H.J.
1982-01-01
A standard approximation in theories of quark bags coupled to a pion field is to treat the pion as an elementary field ignoring its substructure and finite size. A difficulty associated with these treatments in the lack of stability of the quark bag due to the rapid increase of the pion pressure on the bad as the bag size diminishes. We investigate the effects of the finite size of the qanti q pion on the pion quark bag coupling by means of a simple nonlocal pion quark interaction. With this amendment the pion pressure on the bag vanishes if the bag size goes to zero. No stability problems are encountered in this description. Furthermore, for extended pions, no longer a maximum is set to the bag parameter B. Therefore 'little bag' solutions may be found provided that B is large enough. We also discuss the possibility of a second minimum in the bag energy function. (orig.)
Multiple-collision model for pion production in relativistic nucleus-nucleus collisions
International Nuclear Information System (INIS)
Vary, J.P.
1978-01-01
A simple model for pion production in relativistic heavy-ion collisions is developed based on nucleon-nucleon data, nuclear density distribution, and the assumption of straight-line trajectories. Multiplicity distributions for total pion production and for negative-pion production are predicted for 40 Ar incident on a Pb 3 O 4 target at 1.8 GeV/nucleon. Production through intermediate baryon resonances reduces the high-multiplicity region but insufficiently to yield agreement with data. This implies the need for a coherent production mechanism
Scrutinizing the pion condensed phase
Energy Technology Data Exchange (ETDEWEB)
Carignano, Stefano; Mammarella, Andrea; Mannarelli, Massimo [INFN, Laboratori Nazionali del Gran Sasso, Assergi (Italy); Lepori, Luca [Universita di Padova, Dipartimento di Fisica e Astronomia, Padova (Italy); Universita dell' Aquila, Dipartimento di Scienze Fisiche e Chimiche, Coppito-L' Aquila (Italy); Pagliaroli, Giulia [INFN, Laboratori Nazionali del Gran Sasso, Assergi (Italy); Gran Sasso Science Institute, L' Aquila (Italy)
2017-02-15
When the isospin chemical potential exceeds the pion mass, charged pions condense in the zero-momentum state forming a superfluid. Chiral perturbation theory provides a very powerful tool for studying this phase. However, the formalism that is usually employed in this context does not clarify various aspects of the condensation mechanism and makes the identification of the soft modes problematic. We re-examine the pion condensed phase using different approaches within the chiral perturbation theory framework. As a first step, we perform a low-density expansion of the chiral Lagrangian valid close to the onset of the Bose-Einstein condensation. We obtain an effective theory that can be mapped to a Gross-Pitaevskii Lagrangian in which, remarkably, all the coefficients depend on the isospin chemical potential. The low-density expansion becomes unreliable deep in the pion condensed phase. For this reason, we develop an alternative field expansion deriving a low-energy Lagrangian analog to that of quantum magnets. By integrating out the ''radial'' fluctuations we obtain a soft Lagrangian in terms of the Nambu-Goldstone bosons arising from the breaking of the pion number symmetry. Finally, we test the robustness of the second-order transition between the normal and the pion condensed phase when next-to-leading-order chiral corrections are included. We determine the range of parameters for turning the second-order phase transition into a first-order one, finding that the currently accepted values of these corrections are unlikely to change the order of the phase transition. (orig.)
Crystal physics with positive pions
International Nuclear Information System (INIS)
Flik, G.
1983-01-01
The π + /μ + lattice channeling is a new method of investigation in solid state physics. In the present thesis axial and planar channeling effects could be observed for the first time in monocrystalline Tantalum for 4, 12 MeV Muons generated by the decay of implanted positive pions. It is found that pions for T + /μ + channeling is investigated in Germanium for low temperatures. For T > 80 K tetrahedral sites are found, but for T < 80 K hexaedral sites or sites in the middle of the Ge-Ge bond are preferred. (BHO)
Two pion correlation from SPACER
International Nuclear Information System (INIS)
Csoergoe, T.; Zimanyi, J.; Pratt, S.
1989-12-01
The correlation function for neutral and negative pions produced in ultrarelativistic heavy ion collisions was calculated without free parameters based on a space-time version of the LUND model, called SPACER: Simulation of Phase space distribution of Atomic nuclear Collisions in Energetic Reactions. This method includes the effect of Bose correlations for the emitted pion pair. Effects arising from correlations between space-time and momentum space distributions are investigated. The results are compared to the data of two different experiments. The role and interpretation of the chaocity parameter are discussed. (D.G.) 14 refs.; 4 figs
Coulomb effects on pions produced in heavy-ion reactions
Energy Technology Data Exchange (ETDEWEB)
Sullivan, J.P.
1981-11-01
Double differential cross sections for the production of ..pi../sup +/ and ..pi../sup -/ near the velocity of the incident beam for pion lab angles less than 40 degrees are presented. The experimental apparatus and the techniques are discussed. Beams of /sup 20/Ne with E/A from 80 to 655 MeV and /sup 40/Ar with E/A = 535 MeV incident on Be, C, NaF, KC1, Cu, and U targets were used. A sharp peak in the ..pi../sup -/ spectrum and a depression in the ..pi../sup +/ spectrum were observed at zero degrees near the incident beam velocity. The effect is explained in terms of Coulomb interactions between the pions and fragments of the incident beam. Least squares fits to the data using the Coulomb correction formulas of Gyulassy and Kauffman and an effective projectile fragment charge are made. The relationship between these data and previously measured pion production and projectile fragmentation data is discussed. The data are also compared to some theoretical models. A simple expression is given for the differential cross section as a function of the projectile mass, target mass, and beam energy.
Real-pion states formed by virtual-pion beam
International Nuclear Information System (INIS)
Yamazaki, Toshimitsu.
1990-04-01
Deeply bound pionic states are discussed from various points of view; highly excited nuclear states as a cluster family of pionic bound states, Σ atom/Σ hypernuclei, halo-like density distributions, virtual pion beam to produce pionic states, etc. (author)
Pion inelastic scattering and the pion-nucleus effective interaction
International Nuclear Information System (INIS)
Carr, J.A.
1983-01-01
This work examines pion inelastic scattering with the primary purpose of gaining a better understanding of the properties of the pion-nucleus interaction. The main conclusion of the work is that an effective interaction which incorporates the most obvious theoretical corrections to the impulse approximation does a good job of explaining pion elastic and inelastic scattering from zero to 200 MeV without significant adjustments to the strength parameters of the force. Watson's multiple scattering theory is used to develop a theoretical interaction starting from the free pion-nucleon interaction. Elastic scattering was used to calibrate the isoscalar central interaction. It was found that the impulse approximation did poorly at low energy, while the multiple scattering corrections gave good agreement with all of the data after a few minor adjustments in the force. The distorted wave approximation for the inelastic transition matrix elements are evaluated for both natural and unnatural parity excitations. The isoscalar natural parity transitions are used to test the reaction theory, and it is found that the effective interaction calibrated by elastic scattering produces good agreement with the inelastic data. Calculations are also shown for other inelastic and charge exchange reactions. It appears that the isovector central interaction is reasonable, but the importance of medium corrections cannot be determined. The unnatural parity transitions are also reasonably described by the theoretical estimate of the spin-orbit interaction, but not enough systematic data exists to reach a firm conclusion
UV dimensional reduction to two from group valued momenta
Arzano, Michele; Nettel, Francisco
2017-04-01
We describe a new model of deformed relativistic kinematics based on the group manifold U (1) × SU (2) as a four-momentum space. We discuss the action of the Lorentz group on such space and illustrate the deformed composition law for the group-valued momenta. Due to the geometric structure of the group, the deformed kinematics is governed by two energy scales λ and κ. A relevant feature of the model is that it exhibits a running spectral dimension ds with the characteristic short distance reduction to ds = 2 found in most quantum gravity scenarios.
STAR Collaboration; Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Alford, J.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Averichev, G. S.; Banerjee, A.; Bellwied, R.; Bhasin, A.
2015-01-01
We report the observation of transverse polarization-dependent azimuthal correlations in charged pion pair production with the STAR experiment in $p^\\uparrow+p$ collisions at RHIC. These correlations directly probe quark transversity distributions. We measure signals in excess of five standard deviations at high transverse momenta, at high pseudorapidities eta>0.5, and for pair masses around the mass of the rho-meson. This is the first direct transversity measurement in p+p collisions. Compar...
Results for the Asymmetry Measurement in Elastic Pion-Proton Scattering at 1.78 and 2.07GeV/c
Alekseev, I. G.; Budkovsky, P. E.; Kanavets, V. P.; Koroleva, L. I.; Morozov, B. V.; Nesterov, V. M.; Ryltsov, V. V.; Sulimov, A. D.; Svirida, D. N.; Zhurkin, V. V.; Beloglazov, Y. A.; Filimonov, E. A.; Kovalev, A. I.; Kruglov, S. P.; Novinsky, D. V.; Shchedrov, V. A.; Sumachev, V. V.; Trautman, V. Y.; Bazhanov, N. A.; Bunyatova, E. I.
2005-08-01
New experimental results from the ITEP-PNPI collaboration are presented on the asymmetry in backward elastic scattering of negative pions on polarized protons in the resonance region. The data were obtained in the angular region (150° - 170°) c.m. at initial momenta 1.78 and 2.07 GeV/c. The results are compared to the predictions of partial wave analyses. The measurement was done at the ITEP accelerator.
Adamczyk, L; Adkins, J K; Agakishiev, G; Aggarwal, M M; Ahammed, Z; Alekseev, I; Alford, J; Aparin, A; Arkhipkin, D; Aschenauer, E C; Averichev, G S; Banerjee, A; Bellwied, R; Bhasin, A; Bhati, A K; Bhattarai, P; Bielcik, J; Bielcikova, J; Bland, L C; Bordyuzhin, I G; Bouchet, J; Brandin, A V; Bunzarov, I; Burton, T P; Butterworth, J; Caines, H; Calderón de la Barca Sánchez, M; Campbell, J M; Cebra, D; Cervantes, M C; Chakaberia, I; Chaloupka, P; Chang, Z; Chattopadhyay, S; Chen, J H; Chen, X; Cheng, J; Cherney, M; Christie, W; Contin, G; Crawford, H J; Das, S; De Silva, L C; Debbe, R R; Dedovich, T G; Deng, J; Derevschikov, A A; di Ruzza, B; Didenko, L; Dilks, C; Dong, X; Drachenberg, J L; Draper, J E; Du, C M; Dunkelberger, L E; Dunlop, J C; Efimov, L G; Engelage, J; Eppley, G; Esha, R; Evdokimov, O; Eyser, O; Fatemi, R; Fazio, S; Federic, P; Fedorisin, J; Feng, Z; Filip, P; Fisyak, Y; Flores, C E; Fulek, L; Gagliardi, C A; Garand, D; Geurts, F; Gibson, A; Girard, M; Greiner, L; Grosnick, D; Gunarathne, D S; Guo, Y; Gupta, S; Gupta, A; Guryn, W; Hamad, A; Hamed, A; Haque, R; Harris, J W; He, L; Heppelmann, S; Heppelmann, S; Hirsch, A; Hoffmann, G W; Hofman, D J; Horvat, S; Huang, B; Huang, X; Huang, H Z; Huck, P; Humanic, T J; Igo, G; Jacobs, W W; Jang, H; Jiang, K; Judd, E G; Kabana, S; Kalinkin, D; Kang, K; Kauder, K; Ke, H W; Keane, D; Kechechyan, A; Khan, Z H; Kikola, D P; Kisel, I; Kisiel, A; Kochenda, L; Koetke, D D; Kollegger, T; Kosarzewski, L K; Kraishan, A F; Kravtsov, P; Krueger, K; Kulakov, I; Kumar, L; Kycia, R A; Lamont, M A C; Landgraf, J M; Landry, K D; Lauret, J; Lebedev, A; Lednicky, R; Lee, J H; Li, X; Li, C; Li, W; Li, Z M; Li, Y; Li, X; Lisa, M A; Liu, F; Ljubicic, T; Llope, W J; Lomnitz, M; Longacre, R S; Luo, X; Ma, Y G; Ma, G L; Ma, L; Ma, R; Magdy, N; Majka, R; Manion, A; Margetis, S; Markert, C; Masui, H; Matis, H S; McDonald, D; Meehan, K; Minaev, N G; Mioduszewski, S; Mohanty, B; Mondal, M M; Morozov, D; Mustafa, M K; Nandi, B K; Nasim, Md; Nayak, T K; Nigmatkulov, G; Nogach, L V; Noh, S Y; Novak, J; Nurushev, S B; Odyniec, G; Ogawa, A; Oh, K; Okorokov, V; Olvitt, D; Page, B S; Pak, R; Pan, Y X; Pandit, Y; Panebratsev, Y; Pawlik, B; Pei, H; Perkins, C; Peterson, A; Pile, P; Planinic, M; Pluta, J; Poljak, N; Poniatowska, K; Porter, J; Posik, M; Poskanzer, A M; Pruthi, N K; Putschke, J; Qiu, H; Quintero, A; Ramachandran, S; Raniwala, R; Raniwala, S; Ray, R L; Ritter, H G; Roberts, J B; Rogachevskiy, O V; Romero, J L; Roy, A; Ruan, L; Rusnak, J; Rusnakova, O; Sahoo, N R; Sahu, P K; Sakrejda, I; Salur, S; Sandweiss, J; Sarkar, A; Schambach, J; Scharenberg, R P; Schmah, A M; Schmidke, W B; Schmitz, N; Seger, J; Seyboth, P; Shah, N; Shahaliev, E; Shanmuganathan, P V; Shao, M; Sharma, M K; Sharma, B; Shen, W Q; Shi, S S; Shou, Q Y; Sichtermann, E P; Sikora, R; Simko, M; Skoby, M J; Smirnov, D; Smirnov, N; Song, L; Sorensen, P; Spinka, H M; Srivastava, B; Stanislaus, T D S; Stepanov, M; Stock, R; Strikhanov, M; Stringfellow, B; Sumbera, M; Summa, B; Sun, X; Sun, Z; Sun, X M; Sun, Y; Surrow, B; Svirida, N; Szelezniak, M A; Tang, A H; Tang, Z; Tarnowsky, T; Tawfik, A N; Thomas, J H; Timmins, A R; Tlusty, D; Tokarev, M; Trentalange, S; Tribble, R E; Tribedy, P; Tripathy, S K; Trzeciak, B A; Tsai, O D; Ullrich, T; Underwood, D G; Upsal, I; Van Buren, G; van Nieuwenhuizen, G; Vandenbroucke, M; Varma, R; Vasiliev, A N; Vertesi, R; Videbæk, F; Viyogi, Y P; Vokal, S; Voloshin, S A; Vossen, A; Wang, G; Wang, Y; Wang, F; Wang, Y; Wang, H; Wang, J S; Webb, J C; Webb, G; Wen, L; Westfall, G D; Wieman, H; Wissink, S W; Witt, R; Wu, Y F; Xiao, Z G; Xie, W; Xin, K; Xu, Q H; Xu, Z; Xu, H; Xu, N; Xu, Y F; Yang, Q; Yang, Y; Yang, S; Yang, Y; Yang, C; Ye, Z; Yepes, P; Yi, L; Yip, K; Yoo, I-K; Yu, N; Zbroszczyk, H; Zha, W; Zhang, X P; Zhang, J; Zhang, Y; Zhang, J; Zhang, J B; Zhang, S; Zhang, Z; Zhao, J; Zhong, C; Zhou, L; Zhu, X; Zoulkarneeva, Y; Zyzak, M
2015-12-11
We report the observation of transverse polarization-dependent azimuthal correlations in charged pion pair production with the STAR experiment in p^{↑}+p collisions at RHIC. These correlations directly probe quark transversity distributions. We measure signals in excess of 5 standard deviations at high transverse momenta, at high pseudorapidities η>0.5, and for pair masses around the mass of the ρ meson. This is the first direct transversity measurement in p+p collisions.
Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Alford, J.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Averichev, G. S.; Banerjee, A.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Bouchet, J.; Brandin, A. V.; Bunzarov, I.; Burton, T. P.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Campbell, J. M.; Cebra, D.; Cervantes, M. C.; Chakaberia, I.; Chaloupka, P.; Chang, Z.; Chattopadhyay, S.; Chen, J. H.; Chen, X.; Cheng, J.; Cherney, M.; Christie, W.; Contin, G.; Crawford, H. J.; Das, S.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; di Ruzza, B.; Didenko, L.; Dilks, C.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, C. M.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Engelage, J.; Eppley, G.; Esha, R.; Evdokimov, O.; Eyser, O.; Fatemi, R.; Fazio, S.; Federic, P.; Fedorisin, J.; Feng, Z.; Filip, P.; Fisyak, Y.; Flores, C. E.; Fulek, L.; Gagliardi, C. A.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Greiner, L.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, S.; Gupta, A.; Guryn, W.; Hamad, A.; Hamed, A.; Haque, R.; Harris, J. W.; He, L.; Heppelmann, S.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Hofman, D. J.; Horvat, S.; Huang, B.; Huang, X.; Huang, H. Z.; Huck, P.; Humanic, T. J.; Igo, G.; Jacobs, W. W.; Jang, H.; Jiang, K.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Khan, Z. H.; Kikola, D. P.; Kisel, I.; Kisiel, A.; Kochenda, L.; Koetke, D. D.; Kollegger, T.; Kosarzewski, L. K.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kulakov, I.; Kumar, L.; Kycia, R. A.; Lamont, M. A. C.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Li, X.; Li, C.; Li, W.; Li, Z. M.; Li, Y.; Li, X.; Lisa, M. A.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, X.; Ma, Y. G.; Ma, G. L.; Ma, L.; Ma, R.; Magdy, N.; Majka, R.; Manion, A.; Margetis, S.; Markert, C.; Masui, H.; Matis, H. S.; McDonald, D.; Meehan, K.; Minaev, N. G.; Mioduszewski, S.; Mohanty, B.; Mondal, M. M.; Morozov, D.; Mustafa, M. K.; Nandi, B. K.; Nasim, Md.; Nayak, T. K.; Nigmatkulov, G.; Nogach, L. V.; Noh, S. Y.; Novak, J.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Okorokov, V.; Olvitt, D.; Page, B. S.; Pak, R.; Pan, Y. X.; Pandit, Y.; Panebratsev, Y.; Pawlik, B.; Pei, H.; Perkins, C.; Peterson, A.; Pile, P.; Planinic, M.; Pluta, J.; Poljak, N.; Poniatowska, K.; Porter, J.; Posik, M.; Poskanzer, A. M.; Pruthi, N. K.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Roy, A.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Sakrejda, I.; Salur, S.; Sandweiss, J.; Sarkar, A.; Schambach, J.; Scharenberg, R. P.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Seger, J.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, M. K.; Sharma, B.; Shen, W. Q.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Sikora, R.; Simko, M.; Skoby, M. J.; Smirnov, D.; Smirnov, N.; Song, L.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Stepanov, M.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Sumbera, M.; Summa, B.; Sun, X.; Sun, Z.; Sun, X. M.; Sun, Y.; Surrow, B.; Svirida, N.; Szelezniak, M. A.; Tang, A. H.; Tang, Z.; Tarnowsky, T.; Tawfik, A. N.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Tripathy, S. K.; Trzeciak, B. A.; Tsai, O. D.; Ullrich, T.; Underwood, D. G.; Upsal, I.; Van Buren, G.; van Nieuwenhuizen, G.; Vandenbroucke, M.; Varma, R.; Vasiliev, A. N.; Vertesi, R.; Videbæk, F.; Viyogi, Y. P.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wang, G.; Wang, Y.; Wang, F.; Wang, Y.; Wang, H.; Wang, J. S.; Webb, J. C.; Webb, G.; Wen, L.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y. F.; Xiao, Z. G.; Xie, W.; Xin, K.; Xu, Q. H.; Xu, Z.; Xu, H.; Xu, N.; Xu, Y. F.; Yang, Q.; Yang, Y.; Yang, S.; Yang, Y.; Yang, C.; Ye, Z.; Yepes, P.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zbroszczyk, H.; Zha, W.; Zhang, X. P.; Zhang, J.; Zhang, Y.; Zhang, J.; Zhang, J. B.; Zhang, S.; Zhang, Z.; Zhao, J.; Zhong, C.; Zhou, L.; Zhu, X.; Zoulkarneeva, Y.; Zyzak, M.; STAR Collaboration
2015-12-01
We report the observation of transverse polarization-dependent azimuthal correlations in charged pion pair production with the STAR experiment in p↑+p collisions at RHIC. These correlations directly probe quark transversity distributions. We measure signals in excess of 5 standard deviations at high transverse momenta, at high pseudorapidities η >0.5 , and for pair masses around the mass of the ρ meson. This is the first direct transversity measurement in p +p collisions.
Total cross sections for pion charge exchange on the proton
Energy Technology Data Exchange (ETDEWEB)
Breitschopf, J.
2006-04-28
This work describes the measurement of total SCX cross sections employing a new 4{pi} scintillation counter to perform transmission measurements in the incident pion energy range from about 38 to 250 MeV. A small 4{pi} detector box consisting of thin plastic scintillators has been constructed. The transmission technique, which was used, relates the number of transmitted charged pions to that of incident beam pions and this way effectively counts events with neutral products. The incoming negative pions were counted by three beam defining counters before they hit a target of very well known size and chemical composition. The target was placed in the box detector which was not sensitive to the neutral particles resulting from the SCX. The total cross section for emerging neutral particles was derived from the comparison of the numbers of the incoming and transmitted charged particles. The total SCX cross section on hydrogen was derived from the transmissions of a CH{sub 2} target, a carbon target and an empty target. For a detailed offline analysis all TDC, QDC and FADC information was recorded in an event by event mode for each triggered beam event. Various corrections had to be applied to the data, such as random correction, the detection of neutrals in the detector, Dalitz decay, pion decay and the radiative pion capture. This measurement covers, as the only experiment, the whole {delta}-resonance and the sp-interference region in one single experimental setup and improves the available data base for the SCX reaction. It is shown that the description of the SCX cross sections is improved if the s-wave amplitudes, that have been fixed essentially by elastic pion-nucleon scattering data, is reduced by (4{+-}1.5)%. The exact value depends on the SCX literature data included and on the parameters of the {delta}{sup 0} Breit-Wigner resonance describing the p{sub 33}-waves. This shows that p-wave as well as s-wave effects should be considered in studies of isospin
Total cross sections for pion charge exchange on the proton
International Nuclear Information System (INIS)
Breitschopf, J.
2006-01-01
This work describes the measurement of total SCX cross sections employing a new 4π scintillation counter to perform transmission measurements in the incident pion energy range from about 38 to 250 MeV. A small 4π detector box consisting of thin plastic scintillators has been constructed. The transmission technique, which was used, relates the number of transmitted charged pions to that of incident beam pions and this way effectively counts events with neutral products. The incoming negative pions were counted by three beam defining counters before they hit a target of very well known size and chemical composition. The target was placed in the box detector which was not sensitive to the neutral particles resulting from the SCX. The total cross section for emerging neutral particles was derived from the comparison of the numbers of the incoming and transmitted charged particles. The total SCX cross section on hydrogen was derived from the transmissions of a CH 2 target, a carbon target and an empty target. For a detailed offline analysis all TDC, QDC and FADC information was recorded in an event by event mode for each triggered beam event. Various corrections had to be applied to the data, such as random correction, the detection of neutrals in the detector, Dalitz decay, pion decay and the radiative pion capture. This measurement covers, as the only experiment, the whole Δ-resonance and the sp-interference region in one single experimental setup and improves the available data base for the SCX reaction. It is shown that the description of the SCX cross sections is improved if the s-wave amplitudes, that have been fixed essentially by elastic pion-nucleon scattering data, is reduced by (4±1.5)%. The exact value depends on the SCX literature data included and on the parameters of the Δ 0 Breit-Wigner resonance describing the p 33 -waves. This shows that p-wave as well as s-wave effects should be considered in studies of isospin symmetry breaking. Interestingly
International Nuclear Information System (INIS)
Bryman, D.
1983-09-01
Some rare pion and kaon decays, which provide clues to the generation puzzle, are discussed. The π→ eν/π→μ/ν branching ratio test of universality and the status of searches for K + → π + rho anti rho are reviewed
Atkinson, D.; de Groot, H. J.; Johnson, P. W.
1991-01-01
From reliable numerical solutions of an approximate Dyson-Schwinger equation for the quark propagator, we obtain values of the pion and kaon decay constants that differ significantly from those obtained recently by Munczek and McKay using ad hoc quark mass functions. We present arguments that the
Weak pion production from nuclei
Indian Academy of Sciences (India)
Abstract. The charged current pion production induced by neutrinos in 12C, 16O and 56Fe nuclei has been studied. The calculations have been done for the coherent as well as the incoherent processes assuming dominance and takes into account the effect of Pauli blocking, Fermi motion and the renormalization of in ...
Pauli Principle and Pion Scattering
Bethe, H. A.
1972-10-01
It is pointed out that if the Pauli principle is taken into account in the discussion of pion scattering by complex nuclei (as it ought, of course, to be) some rather implausible consequences of some earlier treatments of this problem can be avoided. (auth)
International Nuclear Information System (INIS)
Bay, A.; Joseph, C.; Loude, J.-F.; Perroud, J.-P.; Ruegger, D.; Schoeri, O.; Steiner, D.; Tran, M.T.
1982-01-01
Two experimental studies of the radiative decay of the pion (π + →e + γγ) have been published so far. Each has measured (1+γ) 2 , where γ is the ratio of the axial and vectorial form factors. An investigation has been carried out giving fuller information on each of these (rare) events detected. (G.F.F.)
Weak pion production from nuclei
Indian Academy of Sciences (India)
The pion production processes from nucleons and nuclei at intermediate energies are important tools to study the hadronic structure. The dynamic models of the hadronic structure are used to calculate the various nucleon and transition form factors which are tested by using the experimental data on photo, electro and.
Intermediate-energy nuclear photoabsorption and the pion optical potential
International Nuclear Information System (INIS)
Christillin, P.
1984-01-01
Nuclear photoabsorption around the pion threshold is schematised as photoproduction of a pion which undergoes final-stae interaction with the nucleus, accounted for by the pion optical potential. It is shown that real pion photoproduction and exchange effects are naturally described by the same mechanism with a non-static pion. The complementarity of photoabsorption to pion physics and its usefulness in gaining new information about pion-nucleus dynamics are stressed. (author)
Energy Technology Data Exchange (ETDEWEB)
Abgrall, N.; Blondel, A.; Bravar, A.; Debieux, S.; Haesler, A.; Korzenev, A.; Murphy, S.; Ravonel, M. [University of Geneva, Geneva (Switzerland); Aduszkiewicz, A.; Dominik, W.; Kielczewska, D.; Kirejczyk, M.; Matulewicz, T.; Posiadala, M.; Skrzypczak, E. [University of Warsaw, Faculty of Physics, Warsaw (Poland); Ali, Y.; Brzychczyk, J.; Majka, Z.; Marcinek, A.; Planeta, R.; Staszel, P.; Wyszynski, O. [Jagiellonian University, Cracow (Poland); Anticic, T.; Kadija, K.; Susa, T. [Rudjer Boskovic Institute, Zagreb (Croatia); Antoniou, N.; Christakoglou, P.; Davis, N.; Diakonos, F.; Kapoyannis, A.; Panagiotou, A.D.; Vassiliou, M. [University of Athens, Athens (Greece); Baatar, B.; Bunyatov, S.A.; Kolesnikov, V.I.; Krasnoperov, A.; Lyubushkin, V.V.; Malakhov, A.I.; Melkumov, G.L.; Tereshchenko, V. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Bay, F.; Luise, S.Di; Rubbia, A.; Sgalaberna, D. [ETH, Zurich (Switzerland); Blumer, J.; Dembinski, H.; Engel, R.; Mathes, H.J.; Roth, M.; Szuba, M.; Ulrich, R.; Unger, M. [Karlsruhe Institute of Technology, Karlsruhe (Germany); Bogomilov, M.; Kolev, D.; Tsenov, R. [University of Sofia, Faculty of Physics, Sofia (Bulgaria); Busygina, O.; Golubeva, M.; Guber, F.; Ivashkin, A.; Kurepin, A.; Marin, V.; Petukhov, O.; Sadovsky, A. [Institute for Nuclear Research, Moscow (Russian Federation); Czopowicz, T.; Dynowski, K.; Grebieszkow, K.; Maksiak, B.; Peryt, W.; Pluta, J.; Slodkowski, M. [Warsaw University of Technology, Warsaw (Poland); Drozhzhova, T.; Feofilov, G.A.; Igolkin, S.; Kondratiev, V.P.; Vechernin, V.V.; Vinogradov, L. [St. Petersburg State University, St. Petersburg (Russian Federation); Dumarchez, J.; Robert, A.; Zambelli, L. [LPNHE, University of Paris VI and VII, Paris (France); Ereditato, A.; Hierholzer, M.; Nirkko, M.; Pistillo, C.; Redij, A. [University of Bern, Bern (Switzerland); Fodor, Z.; Fulop, A.; Kiss, T.; Laszlo, A.; Marton, K.; Palla, G.; Sipos, R.; Tolyhi, T.; Vesztergombi, G. [KFKI Research Institute for Particle and Nuclear Physics, Budapest (Hungary); Gazdzicki, M. [Jan Kochanowski University in Kielce, Kielce (Poland); University of Frankfurt, Frankfurt (Germany); Grzeszczuk, A.; Kaptur, E.; Kisiel, J.; Kowalski, S.; Larsen, D.; Pulawski, S.; Schmidt, K.; Wilczek, A.; Zipper, W. [University of Silesia, Katowice (Poland); Hasegawa, T.; Kobayashi, T.; Nakadaira, T.; Nishikawa, K.; Sakashita, K.; Sekiguchi, T.; Shibata, M.; Tada, M. [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki (Japan); Idczak, R.; Kovesarki, P.; Turko, L. [University of Wroclaw, Wroclaw (Poland); Jokovic, D.; Manic, D.; Puzovic, J.; Savic, M. [University of Belgrade, Belgrade (Serbia); Kleinfelder, S. [University of California, Irvine (United States); Mackowiak-Pawlowska, M.; Renfordt, R.; Rustamov, A.; Stroebele, H. [University of Frankfurt, Frankfurt (Germany); Matveev, V. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Institute for Nuclear Research, Moscow (Russian Federation); Mrowczynski, S.; Rybczynski, M.; Seyboth, P.; Stefanek, G.; Wlodarczyk, Z.; Wojtaszek-Szwarc, A. [Jan Kochanowski University in Kielce, Kielce (Poland); Palczewski, T.; Rondio, E.; Stepaniak, J. [National Centre for Nuclear Research, Warsaw (Poland); Paul, T.; Veberic, D. [University Nova Gorica, Laboratory of Astroparticle Physics, Nova Gorica (Slovenia); Popov, B.A. [Joint Institute for Nuclear Research, Dubna (Russian Federation); LPNHE, University of Paris VI and VII, Paris (France); Rauch, W. [Fachhochschule Frankfurt, Frankfurt (Germany); Roehrich, D. [University of Bergen, Bergen (Norway); Collaboration: NA61/SHINE Collaboration
2014-03-15
We present experimental results on inclusive spectra and mean multiplicities of negatively charged pions produced in inelastic p+p interactions at incident projectile momenta of 20, 31, 40, 80 and 158 GeV/c (√(s) = 6.3, 7.7, 8.8, 12.3 and 17.3 GeV, respectively). The measurements were performed using the large acceptance NA61/SHINE hadron spectrometer at the CERN super proton synchrotron. Two-dimensional spectra are determined in terms of rapidity and transverse momentum. Their properties such as the width of rapidity distributions and the inverse slope parameter of transverse mass spectra are extracted and their collision energy dependences are presented. The results on inelastic p+p interactions are compared with the corresponding data on central Pb+Pb collisions measured by the NA49 experiment at the CERN SPS. The results presented in this paper are part of the NA61/SHINE ion program devoted to the study of the properties of the onset of deconfinement and search for the critical point of strongly interacting matter. They are required for interpretation of results on nucleus-nucleus and proton-nucleus collisions. (orig.)
Abgrall, N; Ali, Y; Anticic, T; Antoniou, N; Baatar, B; Bay, F; Blondel, A; Blumer, J; Bogomilov, M; Bravar, A; Brzychczyk, J; Bunyatov, S A; Busygina, O; Christakoglou, P; Czopowicz, T; Davis, N; Debieux, S; Dembinski, H; Diakonos, F; Di Luise, S; Dominik, W; Drozhzhova, T; Dumarchez, J; Dynowski, K; Engel, R; Ereditato, A; Feofilov, G A; Fodor, Z; Fulop, A; Gazdzicki, M; Golubeva, M; Grebieszkow, K; Grzeszczuk, A; Guber, F; Haesler, A; Hasegawa, T; Hierholzer, M; Idczak, R; Igolkin, S; Ivashkin, A; Jokovic, D; Kadija, K; Kapoyannis, A; Katrynska, N; Kaptur, E; Kielczewska, D; Kirejczyk, M; Kisiel, J; Kiss, T; Kleinfelder, S; Kobayashi, T; Kolesnikov, V I; Kolev, D; Kondratiev, V P; Korzenev, A; Kovesarki, P; Kowalski, S; Krasnoperov, A; Kurepin, A; Larsen, D; Laszlo, A; Lyubushkin, V V; Mackowiak-Pawlowska, M; Majka, Z; Maksiak, B; Malakhov, A I; Manic, D; Marcinek, A; Marin, V; Marton, K; Mathes, H J; Matulewicz, T; Matveev, V; Melkumov, G.L; Mrowczynski, St; Murphy, S; Nakadaira, T; Nirkko, M; Nishikawa, K; Palczewski, T; Palla, G; Panagiotou, A D; Paul, T; Pistillo, C; Peryt, W; Petukhov, O; Planeta, R; Pluta, J; Popov, B A; Posiadala, M; Pulawski, S; Puzovic, J; Rauch, W; Ravonel, M; Redij, A; Renfordt, R; Robert, A; Rohrich, D; Rondio, E; Roth, M; Rubbia, A; Rustamov, A; Rybczynski, M; Sadovsky, A; Sakashita, K; Savic, M; Schmidt, K; Sekiguchi, T; Seyboth, P; Sgalaberna, D; Shibata, M; Sipos, R; Skrzypczak, E; Slodkowski, M; Staszel, P; Stefanek, G; Stepaniak, J; Strobele, H; Susa, T; Szuba, M; Tada, M; Tereshchenko, V; Tolyhi, T; Tsenov, R; Turko, L; Ulrich, R; Unger, M; Vassiliou, M; Veberic, D; Vechernin, V V; Vesztergombi, G; Vinogradov, L; Wilczek, A; Wlodarczyk, Z; Wojtaszek-Szwarc, A; Wyszynski, O; Zambelli, L; Zipper, W
2014-01-01
We present experimental results on inclusive spectra and mean multiplicities of negatively charged pions produced in inelastic p+p interactions at incident projectile momenta of 20, 31, 40, 80 and 158GeV/c ($\\sqrt{s}$ = 6.3, 7.7, 8.8, 12.3 and 17.3GeV, respectively). The measurements were performed using the large acceptance NA61/SHINE hadron spectrometer at the CERN super proton synchrotron. Two-dimensional spectra are determined in terms of rapidity and transverse momentum. Their properties such as the width of rapidity distributions and the inverse slope parameter of transverse mass spectra are extracted and their collision energy dependences are presented. The results on inelastic p+p interactions are compared with the corresponding data on central Pb+Pb collisions measured by the NA49 experiment at the CERN SPS. The results presented in this paper are part of the NA61/SHINE ion program devoted to the study of the properties of the onset of deconfinement and search for the critical point of strongly inter...
Pion scattering to 8- stretched states in 60Ni
International Nuclear Information System (INIS)
Clausen, B.L.
1988-03-01
Using the Energetic Pion Channel and Spectrometer at the Los Alamos Meson Physics Facility, differential cross sections for pion scattering were measured for ten previously known J/sup π/ = 8/sup /minus// stretched states in 60 Ni. A possible new pure isoscalar stretched state was also found. The data were taken near the /DELTA//sub 3,3/-resonance using 162 MeV incident pions and scattering angles of 65/degree/, 80/degree/, and 90/degree/ for π + and 65/degree/ and 80/degree/ for π/sup /minus//. The analysis of the 60 Ni data found that the use of Woods-Saxon wave functions in the theoretical calculations gave much better agreement with data than the use of the usual harmonic oscillator wave functions. The WS theory gave better predictions of: the angle at which the π/sup /minus// and π + angular distributions are maximum, the ratios of π/sup /minus// to π + cross sections for pure isovector states (which were much larger than unity), and the absolute size of the cross sections for all states (so that the normalization factor necessary to arrive at agreement of theory with data was closer to unity). The theoretical calculations used the distorted wave impulse approximation, including new methods for unbound states. The sensitivities of the calculations to input parameters were investigated. This analysis using WS wave functions was extended to five other nuclei ( 12 C, 14 C, 16 O, 28 Si, and 54 Fe) on which both pion scattering and electron scattering have been done. A significant improvement in arriving at a normalization factor close to unity was found when WS wave functions were consistently used for analyzing both pion and electron inelastic scattering data. 101 refs., 26 figs., 13 tabs
Helicons in uniform fields. II. Poynting vector and angular momenta
Stenzel, R. L.; Urrutia, J. M.
2018-03-01
The orbital and spin angular momenta of helicon modes have been determined quantitatively from laboratory experiments. The current density is obtained unambiguously from three dimensional magnetic field measurements. The only approximation made is to obtain the electric field from Hall Ohm's law which is usually the case for low frequency whistler modes. This allows the evaluation of the Poynting vector from which the angular momentum is obtained. Comparing two helicon modes (m = 0 and m = 1), one can separate the contribution of angular momentum of a rotating and non-rotating wave field. The orbital angular momentum is important to assess the wave-particle interaction by the transverse Doppler shift of rotating waves which has not been considered so far.
International Nuclear Information System (INIS)
Gibbs, W.R.; Kaufmann, W.B.; Siegel, P.B.
1985-01-01
Calculations of pion single charge exchange using the PWIA and DWIA are presented. Emphasis is given to the effects of absorbtion and blocking. A microscopic calculation of the 0 0 excitation and low energy angular distribution is in excellent agreement with the data. A fixed nucleon multiple scattering calculation of the pion double charge exchange reaction is presented. Various valence neutron wave functions are used, and the contributions of different spatial orientations of the last two neutrons to the reaction are examined. The DCX cross section is found to be very sensitive to the inclusion of correlations in the two-neutron wave function. Satisfactory agreement with DCX data on 14 C can be obtained using a nucleonic picture of the nucleus
International Nuclear Information System (INIS)
Bay, A.; Joseph, C.; Loude, J.-F.; Perroud, J.-P.; Rueegger, D.; Schoeri, O.; Steiner, D.; Tran, M.T.
1982-01-01
So far, only two experimental studies of the radiative decay of the pion (π + →e + γγ) have been reported. From these studies the ratio γ of the axial and the vector weak form factors of the pion can be extracted. The present knowledge of γ is based on 121 events and 226 events only; furthermore an ambiguity in the absolute value of γ associated with its sign still remains. The authors therefore undertook a measurement of this rare decay using a magnetic spectrometer and a large array of 64 NaI modules each with a square cross section of 63 x 63 mm 2 and a length of 406 mm to detect in coincidence the positron and the photon respectively. (Auth.)
Neutral Pion Photoproduction on Neutron
Bulychev, S. A.; Kudryavtsev, A. E.; Kulikov, V. V.; Martem'yanov, M. A.; Tarasov, V. E.; Briscoe, W. J.; Strakovsky, I. I.
2017-12-01
The reaction γ n → π0 n is investigated both theoretically and experimentally as an important step toward determining the electromagnetic coupling constants of the N* and Δ* resonances [1]. We analyze the data on the collisions of γ quanta with energies between 200 and 800 MeV with a deuterium target collected by the A2 experiment in Mainz, Germany. These complement the data for neutral-pion photoproduction on protons obtained by the same experiment [2].
Pion scattering and nuclear dynamics
International Nuclear Information System (INIS)
Johnson, M.B.
1988-01-01
A phenomenological optical-model analysis of pion elastic scattering and single- and double-charge-exchange scattering to isobaric-analog states is reviewed. Interpretation of the optical-model parameters is briefly discussed, and several applications and extensions are considered. The applications include the study of various nuclear properties, including neutron deformation and surface-fluctuation contributions to the density. One promising extension for the near future would be to develop a microscopic approach based on powerful momentum-space methods brought to existence over the last decade. In this, the lowest-order optical potential as well as specific higher-order pieces would be worked out in terms of microscopic pion-nucleon and delta-nucleon interactions that can be determined within modern meson-theoretical frameworks. A second extension, of a more phenomenological nature, would use coupled-channel methods and shell-model wave functions to study dynamical nuclear correlations in pion double charge exchange. 35 refs., 11 figs., 1 tab
Energy Technology Data Exchange (ETDEWEB)
Sorrell, Lee Ronald [Michigan State Univ., East Lansing, MI (United States)
1995-01-01
The nuclear dependence of inclusive direct photon production and inclusive neutral meson production by a 515 GeV/c $\\pi^-$ beam has been measured using data collected by the E706 experiment during the 19.90 fixed, target run at the Fermi National Accelerator Laboratory. The experiment utilized a finely segmented liquid argon calorimeter and a high precision charged particle spectrometer to make precision measurements of inclusive direct photon, neutral pion, and $\\eta$ production in the rapidity interval from -0.75 < $y$ < 0.75. The $\\pi^0$ data is reported for the $P_T$ range from 0.6 GeV /c to 12 GeV /c, while the $\\eta$ data is reported for the range from 3.5 GeV /c to 7.0 GeV /c. The direct photon nuclear dependence results are reported for the range from approxlmately 4.0 GeV/c to 8.5 GeV/c. The data from the beryllium and copper targets have been fit using the parameterization $\\sigma_A$ = $\\sigma_0$ x $A^{\\alpha}$. The neutral meson results are in good agreement with previous charged meson results. The direct photon results are consistent with no anomalous enhancement.
Measurement of the pion polarizabilities at COMPASS
Guskov, A V
2006-01-01
The electromagnetic structure of pions is probed in $\\pi\\gamma$ Compton scattering in inverse kinematics (Primakoff effect) and described by the electric ($\\alpha_{\\pi}$) and magnetic ($\\beta_{\\pi}$) polarizabilities, that depend on the rigidity of pion’s internal structure as a composite particle. Values for pion polarizabilities can be extracted from the comparison of the theoretically predicted (under approximation of unstructured pion) cross section of Primakoff scattering and the measured cross section. The high beam intensity, good spectrometer resolution, the high rate capability, the high acceptance and possibility to use pion and muon beams, that are unique to the COMPASS experiment provide the tools to measure precisely the pion polarizabilities in the $\\pi^{-} + (A,Z)\\rightarrow\\pi^{-} + (A,Z) + \\gamma$ Primakoff reaction. This cross section is related to the cross section of Compton scattering on pion. A precise tracking system, electromagnetic and hadron calorimeters provide good conditions for...
The pion mass: Looking for its origins
International Nuclear Information System (INIS)
Peccei, R.D.
1985-10-01
After explaining why pions are special excitations in QCD, I discuss how the pion mass reflects directly the dynamical scale of the strong interactions (Λsub(QCD)) and the scale of breaking of the weak interactions (Λsub(F)). To actually calculate the pion mass, however, requires understanding the origin of the quark masses and so I compare and contrast approaches to this latter problem, based on composite models and on superstrings. (orig.)
Single- and double-charge exchange at low pion energies
International Nuclear Information System (INIS)
Baer, H.W.
1991-01-01
A review is given of pion single- and double-charge exchange reactions at incident energies of 25 to 65 MeV leading to isobaric analog states, and in the case of double-charge exchange leading to the ground state of the residual nucleus. The crucial role of the higher nuclear transparency at low pion energies for the analysis of the data in terms of single and double scattering is demonstrated. The large effects on double-charge exchange produced by the spatial correlations in nuclear wave functions are evident. The data on 1f 7/2 nuclei at 35 MeV are used to establish the general validity of a shell-model-based two-amplitude model for these transitions. Recent measurements of the energy dependence between 25 and 65 MeV of double-charge exchange cross sections at forward angles are presented and discussed. 33 refs., 19 figs
Evaluation of Light Collection System for Pion and Kaon Experiments in Hall C at Jefferson Lab
Roustom, Salim
2017-09-01
The neutral pion and the kaon are opportune to study the hadron structure through General Parton Distributions, which can be viewed as spatial densities at different momenta of the quarks inside the proton. To study hadron structure with pion or kaon experiments in Hall C at 12 GeV Jefferson Lab, one must analyze the final state neutral pions and kaons and their decay products. For the analysis of these particles, dedicated detectors based on the Cherenkov or scintillation mechanism are used, e.g. the HMS and SHMS aerogel detectors and the PbWO4-based Neutral Particle Spectrometer. A critical part of these detectors is the light collection system. Photomultiplier Tubes (PMTs) have many advantages, however, they are sensitive to magnetic fields and can get damaged by elevated helium levels in the atmosphere. An alternative to PMTs are Avalanche Photodiodes (APDs). APDs are sensitive to background noise, temperature, and radiation. It is thus important to evaluate the benefits of each light collection system and optimize operating conditions to ensure performance over a reasonably long time. I will present a performance study of PMTs exposed to elevated levels of helium and a comparison of APDs as alternatives, as well as new, compact readout methods. Supported in part by NSF Grants PHY-1714133, PHY-1530874, PHY-1306227 and PHY-1306418.
Abramov, V.V.; Akchurin, N.; Atanasov, I.; Baiatian, G.; Ball, A.; Banerjee, S.; de Barbaro, P.; Barnes, V.; Bencze, G.; Bodek, A.; Booke, M.; Budd, H.; Cremaldi, L.; Cushman, P.; Dugad, S.R.; Dimitrov, L.; Dyshkant, A.; Elias, J.; Evdokimov, V.N.; Fong, D.; Freeman, J.; Genchev, V.; Goncharov, P.I.; Green, D.; Gurtu, A.; Hagopian, V.; Iaydjiev, P.; Korneev, Yu.; Krinitsyn, A.; Krishnaswami, G.; Krishnaswamy, M.R.; Kryshkin, V.; Kunori, S.; Laasanen, A.; Lazic, D.; Levchuk, L.; Litov, L.; Mondal, N.K.; Moulik, T.; Narasimham, V.S.; Nemashkalo, A.; Onel, Y.; Petrov, P.; Petukhov, Yu.; Piperov, S.; Popov, V.; Reidy, J.; Ronzhin, A.; Ruchti, R.; Singh, J.B.; Shen, Q.; Sirunyan, A.; Skuja, A.; Skup, E.; Sorokin, P.; Sudhakar, K.; Summers, D.; Szoncso, F.; Tereshenko, S.I.; Timmermans, C.; Tonwar, S.C.; Turchanovich, L.; Tyukov, V.; Volodko, A.; Yukaev, A.; Zaitchenko, A.; Zatserklyaniy, A.; Korneev, Yu.
2001-01-01
We report on the response of a prototype CMS hadron calorimeter module to charged particle beams of pions, muons, and electrons with momenta up to 375 GeV/c. The data were taken at the H2 and H4 beamlines at CERN in 1995 and 1996. The prototype sampling calorimeter used copper absorber plates and scintillator tiles with wavelength shifting fibers for readout. The effects of a magnetic field of up to 3 Tesla on the response of the calorimeter to muons, electrons, and pions are presented, and the effects of an upstream lead tungstate crystal electromagnetic calorimeter on the linearity and energy resolution of the combined calorimetric system to hadrons are evaluated. The results are compared with Monte Carlo simulations and are used to optimize the choice of total absorber depth, sampling frequency, and longitudinal readout segmentation.
A Precision Measurement of the Neutral Pion Lifetime via the Primakoff Effect
Energy Technology Data Exchange (ETDEWEB)
Clinton, Eric [Univ. of Massachusetts, Amherst, MA (United States)
2007-09-01
The neutral pion radiative width has been measured to 8.411 eV ± 1.8% + 1.13% - 1.70% (lifetime = 7.826 ± 0.14 + 0.088 - 0.133 x 10^{-17} s) utilizing the Primakoff effect and roughly 4.9 to 5.5 GeV photons at the Thomas Jefferson National Accelerator Facility in Newport News, VA. The Hall B Photon Tagger, the Hall B Pair Spectrometer, a state of the art Hybrid Calorimter enabled precision incident photon energy measurement, photon flux measurement, and neutral pion identification, respectively. With these and other hardware and software tools, elastic neutral pion yields were extracted from the data. A well developed and understood simulation calculated geometric and software cut efficiency curves. The simulation also provided photo-pion production response functions to fit the experimental cross sections and extract the Primakoff cross section and thus the neutral pion radiative width and lifetime. Future work includes improving understanding of the nuclear incoherent process and any other background sources of elastic neutral pions in this data.
Abat, E; Addy, T N; Adragna, P; Aharrouche, M; Ahmad, A; Akesson, T P A; Aleksa, M; Alexa, C; Anderson, K; Andreazza, A; Anghinolfi, F; Antonaki, A; Arabidze, G; Arik, E; Atkinson, T; Baines, J; Baker, O K; Banfi, D; Baron, S; Barr, A J; Beccherle, R; Beck, H P; Belhorma, B; Bell, P J; Benchekroun, D; Benjamin, D P; Benslama, K; Bergeaas Kuutmann, E; Bernabeu, J; Bertelsen, H; Binet, S; Biscarat, C; Boldea, V; Bondarenko, V G; Boonekamp, M; Bosman, M; Bourdarios, C; Broklova, Z; Burckhart Chromek, D; Bychkov, V; Callahan, J; Calvet, D; Canneri, M; Capeans Garrido, M; Caprini, M; Cardiel Sas, L; Carli, T; Carminati, L; Carvalho, J; Cascella, M; Castillo, M V; Catinaccio, A; Cauz, D; Cavalli, D; Cavalli Sforza, M; Cavasinni, V; Cetin, S A; Chen, H; Cherkaoui, R; Chevalier, L; Chevallier, F; Chouridou, S; Ciobotaru, M; Citterio, M; Clark, A; Cleland, B; Cobal, M; Cogneras, E; Conde Muino, P; Consonni, M; Constantinescu, S; Cornelissen, T; Correard, S; Corso Radu, A; Costa, G; Costa, M J; Costanzo, D; Cuneo, S; Cwetanski, P; Da Silva, D; Dam, M; Dameri, M; Danielsson, H O; Dannheim, D; Darbo, G; Davidek, T; De, K; Defay, P O; Dekhissi, B; Del Peso, J; Del Prete, T; Delmastro, M; Derue, F; Di Ciaccio, L; Dita, S; Dittus, F; Djama, F; Djobava, T; Dobos, D; Dobson, M; Dolgoshein, B A; Dotti, A; Drake, G; Drasal, Z; Dressnandt, N; Driouchi, G; Drohan, J; Ebenstein, W L; Eerola, P; Eerola, P; Efthymiopoulos, I; Egorov, K; Eifert, T F; Einsweiler, K; El Kacimi, M; Elsing, M; Emelyanov, D; Escobar, C; Etienvre, A I; Fabich, A; Facius, K; Fakhr-Edine, A I; Fanti, M; Farbin, A; Farthouat, P; Fassouliotis, D; Fayard, L; Febbraro, R; Fedin, O L; Fenyuk, A; Fergusson, D; Ferrari, P; Ferrari, R; Ferreira, B C; Ferrer, A; Ferrere, D; Filippini, G; Flick, T; Fournier, D; Francavilla, P; Francis, D; Froeschl, R; Froidevaux, D; Fullana, E; Gadomski, S; Gagliardi, G; Gagnon, P; Gallas, M; Gallop, B J; Gameiro, S; Gan, K K; Garcia, R; Garcia, C; Gavrilenko, I L; Gemme, C; Gerlach, P; Ghodbane, N; Giakoumopoulou, V; Giangiobbe, V; Giokaris, N; Di Girolamo, B; Glonti, G; Goettfert, T; Golling, T; Gollub, N; Gomes, A; Gomez, M D; Gonzalez-Sevilla, S; Goodrick, M J; Gorfine, G; Gorini, B; Goujdami, D; Grahn, K J; Grenier, P; Grigalashvili, N; Grishkevich, Y; Grosse-Knetter, J; Gruwe, M; Guicheney, C; Gupta, A; Haeberli, C; Haertel, R; Hajduk, Z; Hakobyan, H; Hance, M; Hansen, D J; Hansen, P H; Hara, K; Harvey Jr, A; Hawkings, R J; Heinemann, F E W; Henriques Correia, A; Henss, T; Hervas, L; Higon, E; Hill, J C; Hoffman, J; Hostachy, J Y; Hruska, I; Hubaut, F; Huegging, F; Hulsbergen, W; Hurwitz, M; Iconomidou-Fayard, L; Jansen, E; Jen-La Plante, I; Johansson, P D C; Jon-And, K; Joos, M; Jorgensen, S; Joseph, J; Kaczmarska, A; Kado, M; Karyukhin, A; Kataoka, M; Kayumov, F; Kazarov, A; Keener, P T; Kekelidze, G D; Kerschen, N; Kersten, S; Khomich, A; Khoriauli, G; Khramov, E; Khristachev, A; Khubua, J; Kittelmann, T H; Klingenberg, R; Klinkby, E B; Kodys, P; Koffas, T; Kolos, S; Konovalov, S P; Konstantinidis, N; Kopikov, S; Korolkov, I; Kostyukhin, V; Kovalenko, S; Kowalski, T Z; Kruger, K; Kramarenko, V; Kudin, L G; Kulchitsky, Y; Le Bihan, A C; Lacasta, C; Lafaye, R; Laforge, B; Lampl, W; Lanni, F; Laplace, S; Lari, T; Latorre, S; Le Bihan, A C; Lechowski, M; Ledroit-Guillon, F; Lehmann, G; Leitner, R; Lelas, D; Lester, C G; Liang, Z; Lichard, P; Liebig, W; Lipniacka, A; Lokajicek, M; Louchard, L; Lourerio, K F; Lucotte, A; Luehring, F; Lund-Jensen, B; Lundberg, B; Ma, H; Mackeprang, R; Maio, A; Maleev, V P; Malek, F; Mandelli, L; Maneira, J; Mangin-Brinet, M; Manousakis, A; Mapelli, L; Marques, C; Marti i García, S; Martin, F; Mathes, M; Mazzanti, M; McFarlane, K W; McPherson, R; Mchedlidze, G; Mehlhase, S; Meirosu, C; Meng, Z; Meroni, C; Miagkov, A; Mialkovski, V; Mikulec, B; Milstead, D; Minashvili, I; Mindur, B; Mitsou, V A; Moed, S; Monnier, E; Moorhead, G; Morettini, P; Morozov, S V; Mosidze, M; Mouraviev, S V; Moyse, E W J; Munar, A; Nadtochi, A V; Nakamura, K; Nechaeva, P; Negri, A; Nemecek, S; Nessi, M; Nesterov, S Y; Newcomer, F M; Nikitine, I; Nikolaev, K; Nikolic-Audit, I; Ogren, H; Oh, S H; Oleshko, S B; Olszowska, J; Onofre, A; Padilla Aranda, C; Paganis, S; Pallin, D; Pantea, D; Paolone, V; Parodi, F; Parsons, J; Parzhitskiy, S; Pasqualucci, E; Passmore, M S; Pater, J; Patrichev, S; Peez, M; Perez Reale, V; Perini, L; Peshekhonov, V D; Petersen, J; Petersen, T C; Petti, R; Phillips, P W; Pilcher, J; Pina, J; Pinto, B; Podlyski, F; Poggioli, L; Poppleton, A; Poveda, J; Pralavorio, P; Pribyl, L; Price, M J; Prieur, D; Puigdengoles, C; Puzo, P; Rohne, O; Ragusa, F; Rajagopalan, S; Reeves, K; Reisinger, I; Rembser, C; Bruckman de Renstrom, P; Reznicek, P; Ridel, M; Risso, P; Riu, I; Robinson, D; Roda, C; Roe, S; Romaniouk, A; Rousseau, D; Rozanov, A; Ruiz, A; Rusakovich, N; Rust, D; Ryabov, Y F; Ryjov, V; Salto, O; Salvachua, B; Salzburger, A; Sandaker, H; Santamarina Rios, C; Santi, L; Santoni, C; Saraiva, J G; Sarri, F; Sauvage, G; Says, L P; Schaefer, M; Schegelsky, V A; Schiavi, C; Schieck, J; Schlager, G; Schlereth, J; Schmitt, C; Schultes, J; Schwemling, P; Schwindling, J; Seixas, J M; Seliverstov, D M; Serin, L; Sfyrla, A; Shalanda, N; Shaw, C; Shin, T; Shmeleva, A; Silva, J; Simion, S; Simonyan, M; Sloper, J E; Smirnov, S Yu; Smirnova, L; Solans, C; Solodkov, A; Solovianov, O; Soloviev, I; Sosnovtsev, V V; Spano, F; Speckmayer, P; Stancu, S; Stanek, R; Starchenko, E; Straessner, A; Suchkov, S I; Suk, M; Szczygiel, R; Tarrade, F; Tartarelli, F; Tas, P; Tayalati, Y; Tegenfeldt, F; Teuscher, R; Thioye, M; Tikhomirov, V O; Timmermans, C; Tisserant, S; Toczek, B; Tremblet, L; Troncon, C; Tsiareshka, P; Tyndel, M; Karagoez Unel, M; Unal, G; Unel, G; Usai, G; Van Berg, R; Valero, A; Valkar, S; Valls, J A; Vandelli, W; Vannucci, F; Vartapetian, A; Vassilakopoulos, V I; Vasilyeva, L; Vazeille, F; Vernocchi, F; Vetter-Cole, Y; Vichou, I; Vinogradov, V; Virzi, J; Vivarelli, I; De Vivie, J B; Volpi, M; Vu Anh, T; Wang, C; Warren, M; Weber, J; Weber, M; Weidberg, A R; Weingarten, J; Wells, P S; Werner, P; Wheeler, S; Wiessmann, M; Wilkens, H; Williams, H H; Wingerter-Seez, I; Yasu, Y; Zaitsev, A; Zenin, A; Zenis, T; Zenonos, Z; Zhang, H; Zhelezko, A; Zhou, N
2010-01-01
The response of the ATLAS barrel calorimeter to pions with momenta from $2$ to $180$~GeV~ is studied in a test--beam at the CERN H8 beam line. %Various methods to reconstruct the deposited pion energies are studied. The mean energy, the energy resolution and the longitudinal and radial shower profiles, and, various observables characterising the shower topology in the calorimeter are measured. The data are compared to Monte Carlo simulations based on a detailed description of the experimental set--up and on various models describing the interaction of particles with matter based on Geant4.
International Nuclear Information System (INIS)
Radyushkin, A.V.
1980-01-01
The calculation of the next-to-leading order corrections to pion form factor Fsub(π)(Q) in the QCD shows that analysis of Fsub(π)(Q) is not a short-distance problem up to Q 2 =10 4 -10 6 GeV 2 . A QCD-inspired model is proposed which in a semi-phenomenological way, takes into account the most important confinement effects. The curve obtained for Fsub(π)(Q) is in good agreement with existing experimental data
Study of the Two-pion Photoproduction on the Deuteron
Energy Technology Data Exchange (ETDEWEB)
Graham, Lewis P. [Univ. of South Carolina, Columbia, SC (United States)
2012-12-01
Acceptance Spectrometer (CLAS), the hadronic products are detected in coincidence with the incident scattered photon on a deuterium target. This makes it possible to measure the single differential cross sections and the decay angular distributions for the production of two pion final states. The measured cross sections will contribute significantly to a better understanding of the coupling strengths that govern the baryonic and mesonic resonances which will push the knowledge of the strong interaction to a next level. We use CLAS to study the two pion channel from the eg3 data set, for resonance production, specifically investigating the exclusive reaction of yd --> p pi^+pi^?n, and comparing the relevant cross sections to already existing data sets. The eg3 data set provided an excellent data set for investigating photo-induced baryonic and mesonic resonances. It contains a large photon tagging range from 1.1 to 5.5 GeV in the study of photo-coupling strengths, as well as an available two pion reaction channel for resonant decay study. These measurements provide unique and coherent results from tagged photons over a broad range of energy, and represent the only two pion production data above 5 GeV at this present time. We found that the data produced good comparable single-differentials cross sections to other existing CLAS (gll dataset) two pion differential cross sections, and an excellent comparable total cross section to published (ELSA and ABBHHM) two pion total cross sections.
Study of the Two Pion Photoproduction on Deuterium
Gauss, Lewis P. Graham, Jr.
Spectrometer (CLAS), the hadronic products are detected in coincidence with the incident scattered photon on a deuterium target. This makes it possible to measure the single differential cross sections and the decay angular distributions for the production of two pion final states. The measured cross sections will contribute significantly to a better understanding of the coupling strengths that govern the baryonic and mesonic resonances which will push the knowledge of the strong interaction to a next level. We use CLAS to study the two pion channel from the eg3 data set, for resonance production, specifically investigating the exclusive reaction of γd → pπ+π n, and comparing the relevant cross sections to already existing data sets. The eg3 data set provided an excellent data set for investigating photo-induced baryonic and mesonic resonances. It contains a large photon tagging range from 1.1 to 5.5 GeV in the study of photo-coupling strengths, as well as an available two pion reaction channel for resonant decay study. These measurements provide unique and coherent results from tagged photons over a broad range of energy, and represent the only two pion production data above 5 GeV at this present time. We found that the data produced good comparable single-differentials cross sections to other existing CLAS (gll dataset) two pion differential cross sections, and an excellent comparable total cross section to published (ELSA and ABBHHM) two pion total cross sections.
The future IKO-PION-MUON-facility
International Nuclear Information System (INIS)
Goudsmit, P.F.A.; Arnold, H.; Dantzig, R. van; Konijn, J.
1975-09-01
Information is given on the pion and muon physics facility planned at the Institute for Nuclear Physics Research (IKO) with special notice of the fluxes of pions and muons expected at this facility, as well as on the structure of these secondary beams
Strangeness production with protons and pions
International Nuclear Information System (INIS)
Dover, C.B.
1993-01-01
We discuss the spectrum of physics questions related to strangeness which could be addressed with intense beams of protons and pions in the few GeV region. We focus on various aspects of strangeness production, including hyperon production in pp collisions, studies of hyperon-nucleon scattering, production of hypernuclei in proton and pion-nucleus collisions, and spin phenomena in hypernuclei
Pion double charge exchange and nuclear structure
International Nuclear Information System (INIS)
Ginocchio, J.N.
1987-01-01
Pion double charge exchange to both the double-analog state and the ground state is studied for medium weight nuclei. The relative cross section of these two transitions and the importance of nuclear structure as a function of pion kinetic energy is examined. 16 figs., 5 tabs
Pion-induced knock-out reactions
International Nuclear Information System (INIS)
Jain, B.K.; Phatak, S.C.
1977-01-01
A strong absorption model for pion-induced Knock-out reactions is proposed. The distortion of the in-coming and out-going pions has been included by (1) computing pion wave number in nuclear medium (dispersive effect) and (2) excluding the central region of the nucleus where the real pion-absorption is dominant (absorption effect). In order to study the dependence of the (π + π + p) reaction on the off-shell pion-nucleon t-matrix, different off-shell extrapolations are used. The magnitude of the cross-sections seems to be sensitive to the type of off-shell extrapolation; their shapes, however, are similar. The theoretical results are compared with experimental data. The agreement between the theoretical results for separable off-shell extrapolation and the data is good. (author)
Azimuthally Differential Pion Femtoscopy in Pb-Pb Collisions at sqrt[s_{NN}]=2.76 TeV.
Adamová, D; Aggarwal, M M; Aglieri Rinella, G; Agnello, M; Agrawal, N; Ahammed, Z; Ahmad, S; Ahn, S U; Aiola, S; Akindinov, A; Alam, S N; Albuquerque, D S D; Aleksandrov, D; Alessandro, B; Alexandre, D; Alfaro Molina, R; Alici, A; Alkin, A; Alme, J; Alt, T; Altinpinar, S; Altsybeev, I; Alves Garcia Prado, C; An, M; Andrei, C; Andrews, H A; Andronic, A; Anguelov, V; Anson, C; Antičić, T; Antinori, F; Antonioli, P; Anwar, R; Aphecetche, L; Appelshäuser, H; Arcelli, S; Arnaldi, R; Arnold, O W; Arsene, I C; Arslandok, M; Audurier, B; Augustinus, A; Averbeck, R; Azmi, M D; Badalà, A; Baek, Y W; Bagnasco, S; Bailhache, R; Bala, R; Baldisseri, A; Ball, M; Baral, R C; Barbano, A M; Barbera, R; Barile, F; Barioglio, L; Barnaföldi, G G; Barnby, L S; Barret, V; Bartalini, P; Barth, K; Bartke, J; Bartsch, E; Basile, M; Bastid, N; Basu, S; Bathen, B; Batigne, G; Batista Camejo, A; Batyunya, B; Batzing, P C; Bearden, I G; Beck, H; Bedda, C; Behera, N K; Belikov, I; Bellini, F; Bello Martinez, H; Bellwied, R; Beltran, L G E; Belyaev, V; Bencedi, G; Beole, S; Bercuci, A; Berdnikov, Y; Berenyi, D; Bertens, R A; Berzano, D; Betev, L; Bhasin, A; Bhat, I R; Bhati, A K; Bhattacharjee, B; Bhom, J; Bianchi, L; Bianchi, N; Bianchin, C; Bielčík, J; Bielčíková, J; Bilandzic, A; Biro, G; Biswas, R; Biswas, S; Blair, J T; Blau, D; Blume, C; Boca, G; Bock, F; Bogdanov, A; Boldizsár, L; Bombara, M; Bonomi, G; Bonora, M; Book, J; Borel, H; Borissov, A; Borri, M; Botta, E; Bourjau, C; Braun-Munzinger, P; Bregant, M; Broker, T A; Browning, T A; Broz, M; Brucken, E J; Bruna, E; Bruno, G E; Budnikov, D; Buesching, H; Bufalino, S; Buhler, P; Buitron, S A I; Buncic, P; Busch, O; Buthelezi, Z; Butt, J B; Buxton, J T; Cabala, J; Caffarri, D; Caines, H; Caliva, A; Calvo Villar, E; Camerini, P; Capon, A A; Carena, F; Carena, W; Carnesecchi, F; Castillo Castellanos, J; Castro, A J; Casula, E A R; Ceballos Sanchez, C; Cerello, P; Chang, B; Chapeland, S; Chartier, M; Charvet, J L; Chattopadhyay, S; Chattopadhyay, S; Chauvin, A; Cherney, M; Cheshkov, C; Cheynis, B; Chibante Barroso, V; Chinellato, D D; Cho, S; Chochula, P; Choi, K; Chojnacki, M; Choudhury, S; Christakoglou, P; Christensen, C H; Christiansen, P; Chujo, T; Chung, S U; Cicalo, C; Cifarelli, L; Cindolo, F; Cleymans, J; Colamaria, F; Colella, D; Collu, A; Colocci, M; Conesa Balbastre, G; Conesa Del Valle, Z; Connors, M E; Contreras, J G; Cormier, T M; Corrales Morales, Y; Cortés Maldonado, I; Cortese, P; Cosentino, M R; Costa, F; Costanza, S; Crkovská, J; Crochet, P; Cuautle, E; Cunqueiro, L; Dahms, T; Dainese, A; Danisch, M C; Danu, A; Das, D; Das, I; Das, S; Dash, A; Dash, S; De, S; De Caro, A; de Cataldo, G; de Conti, C; de Cuveland, J; De Falco, A; De Gruttola, D; De Marco, N; De Pasquale, S; De Souza, R D; Degenhardt, H F; Deisting, A; Deloff, A; Deplano, C; Dhankher, P; Di Bari, D; Di Mauro, A; Di Nezza, P; Di Ruzza, B; Diaz Corchero, M A; Dietel, T; Dillenseger, P; Divià, R; Djuvsland, Ø; Dobrin, A; Domenicis Gimenez, D; Dönigus, B; Dordic, O; Drozhzhova, T; Dubey, A K; Dubla, A; Ducroux, L; Duggal, A K; Dupieux, P; Ehlers, R J; Elia, D; Endress, E; Engel, H; Epple, E; Erazmus, B; Erhardt, F; Espagnon, B; Esumi, S; Eulisse, G; Eum, J; Evans, D; Evdokimov, S; Fabbietti, L; Fabris, D; Faivre, J; Fantoni, A; Fasel, M; Feldkamp, L; Feliciello, A; Feofilov, G; Ferencei, J; Fernández Téllez, A; Ferreiro, E G; Ferretti, A; Festanti, A; Feuillard, V J G; Figiel, J; Figueredo, M A S; Filchagin, S; Finogeev, D; Fionda, F M; Fiore, E M; Floris, M; Foertsch, S; Foka, P; Fokin, S; Fragiacomo, E; Francescon, A; Francisco, A; Frankenfeld, U; Fronze, G G; Fuchs, U; Furget, C; Furs, A; Fusco Girard, M; Gaardhøje, J J; Gagliardi, M; Gago, A M; Gajdosova, K; Gallio, M; Galvan, C D; Gangadharan, D R; Ganoti, P; Gao, C; Garabatos, C; Garcia-Solis, E; Garg, K; Garg, P; Gargiulo, C; Gasik, P; Gauger, E F; Gay Ducati, M B; Germain, M; Ghosh, P; Ghosh, S K; Gianotti, P; Giubellino, P; Giubilato, P; Gladysz-Dziadus, E; Glässel, P; Goméz Coral, D M; Gomez Ramirez, A; Gonzalez, A S; Gonzalez, V; González-Zamora, P; Gorbunov, S; Görlich, L; Gotovac, S; Grabski, V; Graczykowski, L K; Graham, K L; Gramling, J L; Greiner, L; Grelli, A; Grigoras, C; Grigoriev, V; Grigoryan, A; Grigoryan, S; Grion, N; Gronefeld, J M; Grosa, F; Grosse-Oetringhaus, J F; Grosso, R; Gruber, L; Grull, F R; Guber, F; Guernane, R; Guerzoni, B; Gulbrandsen, K; Gunji, T; Gupta, A; Gupta, R; Guzman, I B; Haake, R; Hadjidakis, C; Hamagaki, H; Hamar, G; Hamon, J C; Harris, J W; Harton, A; Hatzifotiadou, D; Hayashi, S; Heckel, S T; Hellbär, E; Helstrup, H; Herghelegiu, A; Herrera Corral, G; Herrmann, F; Hess, B A; Hetland, K F; Hillemanns, H; Hippolyte, B; Hladky, J; Horak, D; Hosokawa, R; Hristov, P; Hughes, C; Humanic, T J; Hussain, N; Hussain, T; Hutter, D; Hwang, D S; Ilkaev, R; Inaba, M; Ippolitov, M; Irfan, M; Isakov, V; Islam, M S; Ivanov, M; Ivanov, V; Izucheev, V; Jacak, B; Jacazio, N; Jacobs, P M; Jadhav, M B; Jadlovska, S; Jadlovsky, J; Jahnke, C; Jakubowska, M J; Janik, M A; Jayarathna, P H S Y; Jena, C; Jena, S; Jercic, M; Jimenez Bustamante, R T; Jones, P G; Jusko, A; Kalinak, P; Kalweit, A; Kang, J H; Kaplin, V; Kar, S; Karasu Uysal, A; Karavichev, O; Karavicheva, T; Karayan, L; Karpechev, E; Kebschull, U; Keidel, R; Keijdener, D L D; Keil, M; Ketzer, B; Mohisin Khan, M; Khan, P; Khan, S A; Khanzadeev, A; Kharlov, Y; Khatun, A; Khuntia, A; Kielbowicz, M M; Kileng, B; Kim, D W; Kim, D J; Kim, D; Kim, H; Kim, J S; Kim, J; Kim, M; Kim, M; Kim, S; Kim, T; Kirsch, S; Kisel, I; Kiselev, S; Kisiel, A; Kiss, G; Klay, J L; Klein, C; Klein, J; Klein-Bösing, C; Klewin, S; Kluge, A; Knichel, M L; Knospe, A G; Kobdaj, C; Kofarago, M; Kollegger, T; Kolojvari, A; Kondratiev, V; Kondratyeva, N; Kondratyuk, E; Konevskikh, A; Kopcik, M; Kour, M; Kouzinopoulos, C; Kovalenko, O; Kovalenko, V; Kowalski, M; Koyithatta Meethaleveedu, G; Králik, I; Kravčáková, A; Krivda, M; Krizek, F; Kryshen, E; Krzewicki, M; Kubera, A M; Kučera, V; Kuhn, C; Kuijer, P G; Kumar, A; Kumar, J; Kumar, L; Kumar, S; Kundu, S; Kurashvili, P; Kurepin, A; Kurepin, A B; Kuryakin, A; Kushpil, S; Kweon, M J; Kwon, Y; La Pointe, S L; La Rocca, P; Lagana Fernandes, C; Lakomov, I; Langoy, R; Lapidus, K; Lara, C; Lardeux, A; Lattuca, A; Laudi, E; Lavicka, R; Lazaridis, L; Lea, R; Leardini, L; Lee, S; Lehas, F; Lehner, S; Lehrbach, J; Lemmon, R C; Lenti, V; Leogrande, E; León Monzón, I; Lévai, P; Li, S; Li, X; Lien, J; Lietava, R; Lindal, S; Lindenstruth, V; Lippmann, C; Lisa, M A; Litichevskyi, V; Ljunggren, H M; Llope, W J; Lodato, D F; Loggins, V R; Loenne, P I; Loginov, V; Loizides, C; Loncar, P; Lopez, X; López Torres, E; Lowe, A; Luettig, P; Lunardon, M; Luparello, G; Lupi, M; Lutz, T H; Maevskaya, A; Mager, M; Mahajan, S; Mahmood, S M; Maire, A; Majka, R D; Malaev, M; Maldonado Cervantes, I; Malinina, L; Mal'Kevich, D; Malzacher, P; Mamonov, A; Manko, V; Manso, F; Manzari, V; Mao, Y; Marchisone, M; Mareš, J; Margagliotti, G V; Margotti, A; Margutti, J; Marín, A; Markert, C; Marquard, M; Martin, N A; Martinengo, P; Martinez, J A L; Martínez, M I; Martínez García, G; Martinez Pedreira, M; Mas, A; Masciocchi, S; Masera, M; Masoni, A; Mastroserio, A; Mathis, A M; Matyja, A; Mayer, C; Mazer, J; Mazzilli, M; Mazzoni, M A; Meddi, F; Melikyan, Y; Menchaca-Rocha, A; Meninno, E; Mercado Pérez, J; Meres, M; Mhlanga, S; Miake, Y; Mieskolainen, M M; Mihaylov, D; Mikhaylov, K; Milano, L; Milosevic, J; Mischke, A; Mishra, A N; Miśkowiec, D; Mitra, J; Mitu, C M; Mohammadi, N; Mohanty, B; Montes, E; Moreira De Godoy, D A; Moreno, L A P; Moretto, S; Morreale, A; Morsch, A; Muccifora, V; Mudnic, E; Mühlheim, D; Muhuri, S; Mukherjee, M; Mulligan, J D; Munhoz, M G; Münning, K; Munzer, R H; Murakami, H; Murray, S; Musa, L; Musinsky, J; Myers, C J; Naik, B; Nair, R; Nandi, B K; Nania, R; Nappi, E; Naru, M U; Natal da Luz, H; Nattrass, C; Navarro, S R; Nayak, K; Nayak, R; Nayak, T K; Nazarenko, S; Nedosekin, A; Negrao De Oliveira, R A; Nellen, L; Nesbo, S V; Ng, F; Nicassio, M; Niculescu, M; Niedziela, J; 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Pop, A; Poppenborg, H; Porteboeuf-Houssais, S; Porter, J; Pospisil, J; Pozdniakov, V; Prasad, S K; Preghenella, R; Prino, F; Pruneau, C A; Pshenichnov, I; Puccio, M; Puddu, G; Pujahari, P; Punin, V; Putschke, J; Qvigstad, H; Rachevski, A; Raha, S; Rajput, S; Rak, J; Rakotozafindrabe, A; Ramello, L; Rami, F; Rana, D B; Raniwala, R; Raniwala, S; Räsänen, S S; Rascanu, B T; Rathee, D; Ratza, V; Ravasenga, I; Read, K F; Redlich, K; Rehman, A; Reichelt, P; Reidt, F; Ren, X; Renfordt, R; Reolon, A R; Reshetin, A; Reygers, K; Riabov, V; Ricci, R A; Richert, T; Richter, M; Riedler, P; Riegler, W; Riggi, F; Ristea, C; Rodríguez Cahuantzi, M; Røed, K; Rogochaya, E; Rohr, D; Röhrich, D; Rokita, P S; Ronchetti, F; Ronflette, L; Rosnet, P; Rossi, A; Rotondi, A; Roukoutakis, F; Roy, A; Roy, C; Roy, P; Rubio Montero, A J; Rui, R; Russo, R; Rustamov, A; Ryabinkin, E; Ryabov, Y; Rybicki, A; Saarinen, S; Sadhu, S; Sadovsky, S; Šafařík, K; Saha, S K; Sahlmuller, B; Sahoo, B; Sahoo, P; Sahoo, R; Sahoo, S; Sahu, P K; Saini, J; Sakai, S; Saleh, M A; Salzwedel, J; Sambyal, S; Samsonov, V; Sandoval, A; Sarkar, D; Sarkar, N; Sarma, P; Sas, M H P; Scapparone, E; Scarlassara, F; Scharenberg, R P; Scheid, H S; Schiaua, C; Schicker, R; Schmidt, C; Schmidt, H R; Schmidt, M O; Schmidt, M; Schukraft, J; Schutz, Y; Schwarz, K; Schweda, K; Scioli, G; Scomparin, E; Scott, R; Šefčík, M; Seger, J E; Sekiguchi, Y; Sekihata, D; Selyuzhenkov, I; Senosi, K; Senyukov, S; Serradilla, E; Sett, P; Sevcenco, A; Shabanov, A; Shabetai, A; Shadura, O; Shahoyan, R; Shangaraev, A; Sharma, A; Sharma, A; Sharma, M; Sharma, M; Sharma, N; Sheikh, A I; Shigaki, K; Shou, Q; Shtejer, K; Sibiriak, Y; Siddhanta, S; Sielewicz, K M; Siemiarczuk, T; Silvermyr, D; Silvestre, C; Simatovic, G; Simonetti, G; Singaraju, R; Singh, R; Singhal, V; Sinha, T; Sitar, B; Sitta, M; Skaali, T B; Slupecki, M; Smirnov, N; Snellings, R J M; Snellman, T W; Song, J; Song, M; Soramel, F; Sorensen, S; Sozzi, F; Spiriti, E; Sputowska, I; Srivastava, B K; Stachel, J; Stan, I; Stankus, P; Stenlund, E; Stiller, J H; Stocco, D; Strmen, P; Suaide, A A P; Sugitate, T; Suire, C; Suleymanov, M; Suljic, M; Sultanov, R; Šumbera, M; Sumowidagdo, S; Suzuki, K; Swain, S; Szabo, A; Szarka, I; Szczepankiewicz, A; Szymanski, M; Tabassam, U; Takahashi, J; Tambave, G J; Tanaka, N; Tarhini, M; Tariq, M; Tarzila, M G; Tauro, A; Tejeda Muñoz, G; Telesca, A; Terasaki, K; Terrevoli, C; Teyssier, B; Thakur, D; Thakur, S; Thomas, D; Tieulent, R; Tikhonov, A; Timmins, A R; Toia, A; Tripathy, S; Trogolo, S; Trombetta, G; Trubnikov, V; Trzaska, W H; Trzeciak, B A; Tsuji, T; Tumkin, A; Turrisi, R; Tveter, T S; Ullaland, K; Umaka, E N; Uras, A; Usai, G L; Utrobicic, A; Vala, M; Van Der Maarel, J; Van Hoorne, J W; van Leeuwen, M; Vanat, T; Vande Vyvre, P; Varga, D; Vargas, A; Vargyas, M; Varma, R; Vasileiou, M; Vasiliev, A; Vauthier, A; Vázquez Doce, O; Vechernin, V; Veen, A M; Velure, A; Vercellin, E; Vergara Limón, S; Vernet, R; Vértesi, R; Vickovic, L; Vigolo, S; Viinikainen, J; Vilakazi, Z; Villalobos Baillie, O; Villatoro Tello, A; Vinogradov, A; Vinogradov, L; Virgili, T; Vislavicius, V; Vodopyanov, A; Völkl, M A; Voloshin, K; Voloshin, S A; Volpe, G; von Haller, B; Vorobyev, I; Voscek, D; Vranic, D; Vrláková, J; Wagner, B; Wagner, J; Wang, H; Wang, M; Watanabe, D; Watanabe, Y; Weber, M; Weber, S G; Weiser, D F; Wessels, J P; Westerhoff, U; Whitehead, A M; Wiechula, J; Wikne, J; Wilk, G; Wilkinson, J; Willems, G A; Williams, M C S; Windelband, B; Witt, W E; Yalcin, S; Yang, P; Yano, S; Yin, Z; Yokoyama, H; Yoo, I-K; Yoon, J H; Yurchenko, V; Zaccolo, V; Zaman, A; Zampolli, C; Zanoli, H J C; Zaporozhets, S; Zardoshti, N; Zarochentsev, A; Závada, P; Zaviyalov, N; Zbroszczyk, H; Zhalov, M; Zhang, H; Zhang, X; Zhang, Y; Zhang, C; Zhang, Z; Zhao, C; Zhigareva, N; Zhou, D; Zhou, Y; Zhou, Z; Zhu, H; Zhu, J; Zhu, X; Zichichi, A; Zimmermann, A; Zimmermann, M B; Zimmermann, S; Zinovjev, G; Zmeskal, J
2017-06-02
We present the first azimuthally differential measurements of the pion source size relative to the second harmonic event plane in Pb-Pb collisions at a center-of-mass energy per nucleon-nucleon pair of sqrt[s_{NN}]=2.76 TeV. The measurements have been performed in the centrality range 0%-50% and for pion pair transverse momenta 0.2
Chiral Dynamics in Pion-Photon Reactions Habilitation
Friedrich, Jan Michael
As the lightest particle of the strong force, the pion plays a central role in the field of strong interactions, and understanding its properties is of prime relevance for understanding the strong interaction in general. The low-energy behaviour of pions is of particular interest. Although the quark-gluon substructure and their quantum chromodynamics is not apparent then, this specific inner structure causes the presence of approximate symmetries in pion-pion interactions and in pion decays, which gives rise to the systematic description of processes involving pions in terms of few low-energy constants. Specifically, the chiral symmetry and its spontaneous and explicit breaking, treated in chiral perturbation theory (ChPT), leads to firm predictions for low-energy properties of the pion. To those belong the electromagnetic polarisabilities of the pion, describing the leading-order structure effect in pion Compton scattering. The research presented in this work is concerned with the interaction of pions and ph...
Bose-Einstein study of position-momentum correlations of charged pions in hadronic Z{sup 0} decays
Energy Technology Data Exchange (ETDEWEB)
Abbiendi, G.; Braibant, S.; Capiluppi, P.; Ciocca, C.; Cuffiani, M.; Dallavalle, G.M.; Fabbri, F.; Giacomelli, G.; Giacomelli, P.; Marcellini, S.; Michelini, A.; Rossi, A.M. [Dipartimento di Fisica dell' Universita di Bologna and INFN, Bologna (Italy); Ainsley, C.; Batley, R.J.; Carter, J.R.; Hill, J.C.; Thomson, M.A.; Ward, C.P.; Ward, D.R. [Cavendish Lab., Cambridge (United Kingdom); Aakesson, P.F.; Burckhart, H.J.; De Roeck, A.; Ferrari, P.; Frey, A.; Gruwe, M.; Hauschild, M.; Hawkings, R.; Meijers, F.; Oh, A.; Plane, D.E.; Rembser, C.; Scharff-Hansen, P.; Schroeder, M.; Smith, A.M.; Wells, P.S.; Wengler, T. [CERN, European Organisation for Nuclear Research, Geneva 23 (Switzerland); Alexander, G.; Bella, G.; Etzion, E.; Grunhaus, J.; Tsur, E. [Tel Aviv Univ., Dept. of Physics and Astronomy, Tel Aviv (Israel); Anagnostou, G.; Bell, P.J.; Charlton, D.G.; Hawkes, C.M.; Jovanovic, P.; O' Neale, S.W.; Turner-Watson, M.F.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wilson, J.A. [Univ. of Birmingham, School of Physics and Astronomy, Birmingham (United Kingdom); Anderson, K.J.; Gupta, A.; Merritt, F.S.; Oreglia, M.J.; Pilcher, J.E.; Teuscher, R. [Univ. of Chicago, Enrico Fermi Inst. and Dept. of Physics, Chicago, IL (United States); Asai, S.; Ishii, K.; Kawagoe, K.; Kawamoto, T.; Kobayashi, T.; Komamiya, S.; Mashimo, T.; Mihara, S.; Mori, T.; Nanjo, H.; Orito, S.; Saeki, T.; Toya, D.; Ueda, I.; Yamashita, S. [Kobe University, Kobe (Japan)]|[Univ. of Tokyo, International Centre for Elementary Particle Physics and Dept. of Physics, Tokyo (Japan); Axen, D.; McKenna, J. [Univ. of British Columbia, Dept. of Physics, Vancouver, BC (Canada); Bailey, I.; Karlen, D.; Keeler, R.K.; McPherson, R.A.; Roney, J.M.; Sobie, R. [Univ. of Victoria, Dept. of Physics, P.O. Box 3055, Victoria, BC (Canada); Barberio, E. [CERN, European Organisation for Nuclear Research, Geneva 23 (Switzerland)]|[Univ. of Melbourne, Victoria (Australia)
2007-12-15
A study of Bose-Einstein correlations in pairs of identically charged pions produced in e{sup +}e{sup -} annihilations at the Z{sup 0} peak has been performed for the first time assuming a non-static emitting source. The results are based on the high statistics data obtained with the OPAL detector at LEP. The correlation functions have been analyzed in intervals of the average pair transverse momentum and of the pair rapidity, in order to study possible correlations between the pion production points and their momenta (position-momentum correlations). The Yano-Koonin and the Bertsch-Pratt parameterizations have been fitted to the measured correlation functions to estimate the geometrical parameters of the source as well as the velocity of the source elements with respect to the overall centre-of-mass frame. The source rapidity is found to scale approximately with the pair rapidity, and both the longitudinal and transverse source dimensions are found to decrease for increasing average pair transverse momenta. (orig.)
Bose-Einstein study of position-momentum correlations of charged pions in hadronic $Z^{0}$ decays
Abbiendi, G.; Akesson, P.F.; Alexander, G.; Anagnostou, G.; Anderson, K.J.; Asai, S.; Axen, D.; Bailey, I.; Barberio, E.; Barillari, T.; Barlow, R.J.; Batley, R.J.; Bechtle, P.; Behnke, T.; Bell, Kenneth Watson; Bell, P.J.; Bella, G.; Bellerive, A.; Benelli, G.; Bethke, S.; Biebel, O.; Boeriu, O.; Bock, P.; Boutemeur, M.; Braibant, S.; Brown, Robert M.; Burckhart, H.J.; Campana, S.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, D.G.; Ciocca, C.; Csilling, A.; Cuffiani, M.; Dado, S.; Dallavalle, G.M.; De Roeck, A.; De Wolf, E.A.; Desch, K.; Dienes, B.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Etzion, E.; Fabbri, F.; Ferrari, P.; Fiedler, F.; Fleck, I.; Ford, M.; Frey, A.; Gagnon, P.; Gary, John William; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Giunta, Marina; Goldberg, J.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gupta, A.; Hajdu, C.; Hamann, M.; Hanson, G.G.; Harel, A.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Herten, G.; Heuer, R.D.; Hill, J.C.; Horvath, D.; Igo-Kemenes, P.; Ishii, K.; Jeremie, H.; Jovanovic, P.; Junk, T.R.; Kanzaki, J.; Karlen, D.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kluth, S.; Kobayashi, T.; Kobel, M.; Komamiya, S.; Kramer, T.; Krasznahorkay, A., Jr.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kupper, M.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Lellouch, D.; Lettso, J.; Levinson, L.; Lillich, J.; Lloyd, S.L.; Loebinger, F.K.; Lu, J.; Ludwig, A.; Ludwig, J.; Mader, W.; Marcellini, S.; Martin, A.J.; Mashimo, T.; Mattig, Peter; McKenna, J.; McPherson, R.A.; Meijers, F.; Menges, W.; Merritt, F.S.; Mes, H.; Meyer, N.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mohr, W.; Mori, T.; Mutter, A.; Nagai, K.; Nakamura, I.; Nanjo, H.; Neal, H.A.; O'Neale, S.W.; Oh, A.; Oreglia, M.J.; Orito, S.; Pahl, C.; Pasztor, G.; Pater, J.R.; Pilcher, J.E.; Pinfold, J.; Plane, D.E.; Pooth, O.; Przybycien, M.; Quadt, A.; Rabbertz, K.; Rembser, C.; Renkel, P.; Roney, J.M.; Rossi, A.M.; Rozen, Y.; Runge, K.; Sachs, K.; Saeki, T.; Sarkisyan, E.K.G.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schieck, J.; Schorner-Sadenius, T.; Schroder, M.; Schumacher, M.; Seuster, R.; Shears, T.G.; Shen, B.C.; Sherwood, P.; Skuja, A.; Smith, A.M.; Sobie, R.; Soldner-Rembold, S.; Spano, F.; Stahl, A.; Strom, David M.; Strohmer, R.; Tarem, S.; Tasevsky, M.; Teuscher, R.; Thomson, M.A.; Torrence, E.; Toya, D.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Ujvari, B.; Vollmer, C.F.; Vannerem, P.; Vertesi, R.; Verzocchi, M.; Voss, H.; Vossebeld, J.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wilson, G.W.; Wilson, J.A.; Wolf, G.; Wyatt, T.R.; Yamashita, S.; Zer-Zion, D.; Zivkovic, Lidija
2007-01-01
A study of Bose-Einstein correlations in pairs of identically charged pions produced in e+e- annihilations at the Z0 peak has been performed for the first time assuming a non-static emitting source. The results are based on the high statistics data obtained with the OPAL detector at LEP. The correlation functions have been analyzed in intervals of the average pair transverse momentum and of the pair rapidity, in order to study possible correlations between the pion production points and their momenta (position-momentum correlations). The Yano-Koonin and the Bertsch-Pratt parameterizations have been fitted to the measured correlation functions to estimate the geometrical parameters of the source as well as the velocity of the source elements with respect to the overall centre-of-mass frame. The source rapidity is found to scale approximately with the pair rapidity, and both the longitudinal and transverse source dimensions are found to decrease for increasing average pair transverse momenta.
A measurement of the pion charge radius
International Nuclear Information System (INIS)
Amendolia, S.R.; Badelek, B.; Batignani, G.; Bedeschi, F.; Bertolucci, E.; Bettoni, D.; Bosisio, L.; Bradaschia, C.; Dell'Orso, M.; Fidecaro, F.; Foa, L.; Focardi, E.; Giazotto, A.; Giorgi, M.A.; Marrocchesi, P.S.; Menzione, A.; Ristori, L.; Scribano, A.; Tonelli, G.; Codino, A.; Fabbri, F.L.; Laurelli, P.; Satta, L.; Spillantini, P.; Zallo, A.; Counihan, M.J.; Frank, S.G.F.; Harvey, J.; Storey, D.; Menasce, D.; Meroni, E.; Moroni, L.
1984-01-01
We report a measurement of the negative pion electromagnetic form factor in the range of space-like four-momentum transfer 0.014 2 2 . The measurement was made by the NA7 collaboration at the CERN SPS, by observing the interaction of 300 GeV pions with the electrons of a liquid hydrogen target. The form factor is fitted by a pole form with a pion radius of (rho 2 )sup(1/2) = 0.657 +- 0.012 fm. (orig.)
Learning about nucleon resonances with pion photoproduction
International Nuclear Information System (INIS)
Walker, R.L.
1989-01-01
This chapter charts the discovery of nucleon resonances from pion-nucleon interactions. It was not until after the Albuquerque meeting in 1953 the experimentalists were able to persuade physicists about the existence of this phenomenon with the discovery of the P 33 resonance. The second and third resonances to be discovered, D 13 and F 15 , were seen as peaks in the total cross section for pion plus photoproduction, from 1956 onwards. Knowledge of pion-nucleon scattering has played an important role in the development of quark models. (UK)
Radiative corrections for pion polarizability experiments
International Nuclear Information System (INIS)
Akhundov, A.A.; Gerzon, S.; Kananov, S.; Moinester, M.A.
1994-08-01
We use the semi-analytical program RCFORGV to evaluate radiative corrections to one-photon radiative emission in the high-energy scattering of pions in the Coulomb field of a nucleus with atomic number Z. It is shown that radiative corrections can simulate a pion polarizability effect. The average effect is α rc π =-β rc π =(0.20±0.05) x 10 -43 cm 3 , for pion energies 40-600 GeV. We also study the range of applicability of the equivalent photon approximation in describing one-photon radiative emission. (author). 21 refs, 6 figs, 1 tab
A new determination of the pion mass
International Nuclear Information System (INIS)
Anagnastopoulos, D.; Belmiloud, D.; El-Khoury, P.; Indelicato, P.; Borchert, G.; Gorke, H.; Gotta, D.; Lenz, S.; Siems, T.; Daum, M.; Frosch, R.; Hauser, P.; Kirch, K.; Simons, L.M.
1996-01-01
Initial measurements concerning the feasibility of a new pion mass determination are described. In a first step, a high-resolution crystal spectrometer was coupled to a cyclotron trap which provides a high pion stopping density, sufficient to check predictions for the cascade process and to measure the stability of the apparatus. A comparison with the measured Cu K α fluorescence line resolves an ambiguity in the value of the pion mass. The preliminary result from this experiment is m π -=(139.57040±0.00045) MeV/c 2 . (orig.)
The pion pole term in electroproduction of off-mass-shell pions
International Nuclear Information System (INIS)
McKellar, B.H.; Ellis, R.G.
1983-01-01
The dependence of the invariant amplitudes for electroproduction of off-mass-shell pions on the pion Born term is investigated when current algebra Ward identities and PCAC are used to determine pion electroproduction invariant amplitudes. The authors show that an amplitude satisfying the Ward identities can be constructed starting from the usual Born terms which do not satisfy them and that this same amplitude will be obtained for a large class of input Born terms
The pion pole term in electroproduction of off-mass-shell pions
International Nuclear Information System (INIS)
Ellis, R.G.; McKellar, B.H.J.
1983-01-01
The dependence of the invariant amplitudes for electroproduction of off-mass-shell pions on the pion Born term is investigated when Current Algebra Ward identities and PCAC are used to determine pion electroproduction invariant amplitudes. It is shown that an amplitude satisfying the Ward identities can be constructed starting from the usual Born terms which do not satisfy them and that this same amplitude will be obtained for a large class of input Born terms
Subthreshold pion production from nucleus-nucleus collisions around 100 MeV/nucleon
Badalá, A.; Barbera, R.; Palmeri, A.; Pappalardo, G. S.; Riggi, F.; Russo, A. C.
1993-12-01
Several global variables were tested with the aim to determine the impact parameter in nucleus-nucleus collisions producing pions at incident energies around 100 MeV/nucleon. The experimental set-up includes the MEDEA multidetector, part of which is used as a π 0 spectrometer, and an additional hodoscope of plastic scintillators to cover very forward angles. A statistical model was used to generate both inclusive and pion-triggered events. Selection of well measured events was made through the measured total parallel momentum. Among the different global variables which were tested, the average parallel velocity was seen to give the best correlation with the impact parameter.
Cariñena, José F.; Rañada, Manuel F.; Santander, Mariano
2017-11-01
The quantization of systems with a position dependent mass (PDM) is studied. We present a method that starts with the study of the existence of Killing vector fields for the PDM geodesic motion (Lagrangian with a PDM kinetic term but without any potential) and the construction of the associated Noether momenta. Then the method considers, as the appropriate Hilbert space, the space of functions that are square integrable with respect to a measure related with the PDM and, after that, it establishes the quantization, not of the canonical momenta p, but of the Noether momenta P instead. The quantum Hamiltonian, that depends on the Noether momenta, is obtained as an Hermitian operator defined on the PDM Hilbert space. In the second part several systems with position-dependent mass, most of them related with nonlinear oscillators, are quantized by making use of the method proposed in the first part.
Low energy pion-pion phase shifts from chiral perturbation theory
International Nuclear Information System (INIS)
Borges, J. Sa; Barbosa, J. Soares; Oguri, V.
1997-01-01
The low energy pion-pion S- and P- experimental phase-shifts are fitted with chiral perturbation theory (Ch PT) amplitude. The low energy pion-pion S- and P- experimental phase-shifts. The parameters l 1 and l 2 of the one loop corrected amplitude are fixed and the corresponding values of the scattering lengths are calculated. We propose that the present method is the best way to fix Ch P T parameters. The unitarization program of current algebra is also discussed. (author)
Negative pion irradiations of the mouse testis
International Nuclear Information System (INIS)
Coggle, J.E.; Lambert, B.E.; Peel, D.M.; Davies, R.W.
1977-01-01
A study has been made of testicular weight-loss in the mouse 28 days after 70 MeV pion irradiation. The data on weight loss after peak or plateau pion irradiation of anaesthetized mice have been compared with those after high-dose-rate 14 MeV electrons and low-dose-rate 200 kVp X-rays. The data points for the initial radiosensitive component of weight loss all fell on the same line; 1 Gy of pions, 14 MeV electrons and X-rays all produced approximately 45% reduction in testicular weight. There was no evidence of a dose-rate effect for rates between 1.2 Gy h -1 and 14 400 Gy h -1 . The r.b.e. of pions for testicular weight loss is therefore unity compared with low-LET electrons and X-rays. (U.K.)
Charged pions polarizability measurement at COMPASS
Guskov, A
2010-01-01
The pion electromagnetic structure can be probed in $\\pi^{−}+(A,Z)\\rightarrow\\pi^{-}+(A,Z)+\\gamma$ Compton scattering in inverse kinematics (Primakoff reaction) and described by the electric $(\\alpha_{\\pi})$ and the magnetic $(\\beta_{\\pi})$ polarizabilities that depend on the rigidity of pion’s internal structure as a composite particle. Values for pion polarizabilities can be extracted from the comparison of the differential cross section for scattering of point-like pions with the measured cross section. The opportunity to measure pion polarizability via the Primakoff reaction at the COMPASS experiment was studied with $a$ $\\pi^{-}$ beam of 190 GeV during pilot run 2004. The obtained results were used for preparation of the new data taking which was performed in 2009.
Pion-nucleus cross sections approximation
International Nuclear Information System (INIS)
Barashenkov, V.S.; Polanski, A.; Sosnin, A.N.
1990-01-01
Analytical approximation of pion-nucleus elastic and inelastic interaction cross-section is suggested, with could be applied in the energy range exceeding several dozens of MeV for nuclei heavier than beryllium. 3 refs.; 4 tabs
Electron linac design for pion radiotherapy
International Nuclear Information System (INIS)
Loew, G.A.; Brown, K.L.; Miller, R.H.; Walz, D.R.
1977-03-01
The electron linac provides a straightforward, state-of-the-art method of producing the primary beam required for a hospital-based multiport pion radiotherapy facility for cancer treatment. The accelerator and associated beam transport system described are capable of generating an electron beam of about 250 kW and delivering it alternately to one of several pion generators and treatment areas. Each pion generator, a prototype of which now exists at the Stanford W. W. Hansen Laboratory, would contain a target for the electron beam and sixty separate superconducting magnet channels which focus the pions in the patient. The considerations which enter the design of a practical linac are presented together with a possible layout of a flexible beam transport system
Low energy theorems in pion production
International Nuclear Information System (INIS)
Holstein, B.R.; Washington Univ., Seattle, WA
1992-01-01
Considerable activity-both theoretical and experimental-has recently taken place involving the threshold and near threshold of pion photo- and electroproduction. This activity is herein summarized and a program for future work is outlined
Pion photoproduction on very light nuclei
International Nuclear Information System (INIS)
Botton, N. de
1981-01-01
The most fruitful frame of interpretation of pion photoproduction on nuclei is a microscopic description which involves - the elementary pion photoproduction amplitude on the nucleon, - the structure of the initial and final nuclear states, - the many-body effects which include the distortion of the pion wave resulting from its strong interaction with the nucleus. According to the specific nature of the performed experiments we have gained knowledge on the elementary photoproduction multipole amplitudes, on the nuclear form factors and on the pion propagation inside the nucleus; we have got some hints on the Δ-nucleon interaction and some of us have been speculating about the manifestation of exotic dibaryonic states. A few selected examples of recent experimental and theoretical work are presented which illustrate, from the point of view of an experimentalist, the possibilities and the limitations of this method of investigation. Some forthcoming developments in the field are also reported. (Auth.)
Pion production models and neutrino factories
International Nuclear Information System (INIS)
Collot, Johann; Kirk, Harold G.; Mokhov, Nikolai V.
2000-01-01
Scenarios for the building of muon colliders or storage rings suitable for the generation of robust neutrino beams call for the generation of a prodigious quantity of pions. These pions are then conducted into a decay channel where the resulting muon decay products can be collected for cooling and subsequent acceleration. Central to this concept is the design and construction of a target which will be highly efficient in producing pions of both signs while mitigating the absorption of these pions before they decay. This design effort is being facilitated by using two computer codes FLUKA and MARS. We present comparisons of the two computer codes and also present a comparison of these codes with available data
PION PRODUCTION MODELS AND NEUTRINO FACTORIES
International Nuclear Information System (INIS)
COLLOT, J.; KIRK, H.G.; MOKHOV, N.V.
2000-01-01
Scenarios for the building of muon colliders or storage rings suitable for the generation of robust neutrino beams call for the generation of a prodigious quantity of pions. These pions are then conducted into a decay channel where the resulting muon decay products can be collected for cooling and subsequent acceleration. Central to this concept is the design and construction of a target which will be highly efficient in producing pions of both signs while mitigating the absorption of these pions before they decay. This design effort is being facilitated by using two computer codes FLUKA and MARS. The authors present comparisons of the two computer codes and also present a comparison of these codes with available data
Measurement of the ^{3}He(e,e'p)pn Reaction at High Missing Energies and Momenta
Energy Technology Data Exchange (ETDEWEB)
Benmokhtar, Fatiha [Rutgers Univ., New Brunswick, NJ (United States)
2004-10-01
We investigate the structure of ^{3}He through the measurement of quasielastic ^{3}He(e,e'). The measurements use the high duty factor electron beam and the high-precision two-spectrometer system in Hall A of the Thomas Jefferson National Accelerator Facility (TJNAF). The measurements were performed in perpendicular kinematics at fixed momentum and energy transfer by the electron, |$\\vec{q}$|= 1.5 GeV/c and omega = 837 MeV, respectively. A description of the reaction in the plane wave impulse approximation is presented. The experimental equipment is described in detail. For the measurements, the kinematics of the experiment are given. The procedures to remove backgrounds and perform radiative corrections, are also discussed in detail. The detailed method of performing radiative corrections in particular is novel to this work. Finally, the resulting cross sections, distorted spectral functions, and asymmetry ATL are presented, and the physics implications are discussed. We extracted cross sections and distorted spectral functions up to high missing momentum, pm up to 1 GeV/c, and up to high missing energies, Em up to 140 MeV, the pion production threshold. The experimental data are much higher in statistics and much more extensive in kinematic coverage than any previous measurement. Theoretical predictions are in good agreement with the data, leading to the conclusion that the cross section at large missing momenta is strongly enhanced by nucleon-nucleon correlations, with additional enhancement from final-state interactions. The conventional NN correlations present in a modern three-body nuclear wave function, along with a modern reaction mechanism theory, appear sufficient to explain the data; there is no strong indication of a need to include any additional exotic physics, such as quark degrees of freedom.
Angular momenta of fission fragments in the {alpha}-accompanied fission of {sup 252}Cf
Energy Technology Data Exchange (ETDEWEB)
Jandel, M.; Kliman, J.; Krupa, L.; Morhac, M. [Slovak Academy of Sciences, Department of Nuclear Physics, Bratislava (Slovakia); Joint Institute for Nuclear Research, Flerov Laboratory for Nuclear Reactions, Dubna (Russian Federation); Hamilton, J.H.; Kormicki, J.; Ramayya, A.V.; Hwang, J.K.; Luo, Y.X.; Fong, D.; Gore, P. [Vanderbilt University, Department of Physics, Nashville, TN (United States); Ter-Akopian, G.M.; Oganessian, Yu.Ts.; Rodin, A.M.; Fomichev, A.S.; Popeko, G.S. [Joint Institute for Nuclear Research, Flerov Laboratory for Nuclear Reactions, Dubna (Russian Federation); Daniel, A.V. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Rasmussen, J.O.; Macchiavelli, A.O.; Stoyer, M.A. [Lawrence Livermore National Laboratory, Livermore, CA (United States); Donangelo, R.; Cole, J.D.
2005-06-01
For the first time, average angular momenta of the ternary fission fragments {sup 100,102}Zr, {sup 106}Mo, {sup 144,146}Ba and {sup 138,140,142}Xe from the {alpha}-accompanied fission of {sup 252}Cf were obtained from relative intensities of prompt {gamma}-ray transitions with the use of the statistical model calculation. Average values of the angular momenta were compared with the corresponding values for the same fission fragments from the binary fission of {sup 252}Cf. Results indicate the presence of a decreasing trend in the average values of angular momenta induced in ternary fission fragments compared to the same binary fission fragments. On the average, the total angular momentum extracted for ternary fission fragments is {proportional_to}1.4{Dirac_h} lower than in binary fission. Consequently, results indicate that the mechanism of the ternary {alpha}-particles emission may directly effect an induction of angular momenta of fission fragments, and possible scenarios of such mechanisms are discussed. Further, the dependence of the angular momenta of {sup 106}Mo and {sup 140}Xe on the number of emitted neutrons from correlated pairs of primary fragments was obtained also showing a decreasing dependence of average angular momenta with increasing number of emitted neutrons. Consequences are briefly discussed. (orig.)
Search for deeply bound pionic states in 208Pb via radiative atomic capture of negative pions
International Nuclear Information System (INIS)
Raywood, K.J.; Lange, J.B.; Jones, G.; Pavan, M.; Sevior, M.E.; Hutcheon, D.A.; Olin, A.; Ottewell, D.; Yen, S.; Lee, S.J.; Sim, K.S.; Altman, A.; Friedman, E.; Trudel, A.
1997-01-01
A search for narrow, deeply bound pionic atom states via atomic radiative capture of negative pions in a target of 208 Pb was carried out for pion kinetic energies of 20 and 25 MeV. Although no clear signature of any such gamma ray emission could be observed in the data, fits of the gamma ray spectra between the energies of 12 and 42 MeV involving a quadratic background together with a pair of peaks (1s, 2p) whose relative intensity was taken from theory yielded an overall strength for the peaks which are consistent (to a 67% confidence level) with radiative capture whose integrated cross section is 20.0 ± 10.0 μb/sr at 90 degree for 20 MeV incident pions. A lower probability (40% confidence level) result was obtained when the fit was carried out without the peaks included, just the continuum background. copyright 1997 The American Physical Society
Pion condensation and neutron star dynamics
International Nuclear Information System (INIS)
Kaempfer, B.
1983-01-01
The question of formation of pion condensate via a phase transition in nuclear matter, especially in the core of neutron stars is reviewed. The possible mechanisms and the theoretical restrictions of pion condensation are summarized. The effects of ultradense equation of state and density jumps on the possible condensation phase transition are investigated. The possibilities of observation of condensation process are described. (D.Gy.)
Pion production cross sections and associated parameters
International Nuclear Information System (INIS)
Bradbury, J.N.
1985-01-01
Negative pions have been used for radiotherapy at the meson factories LAMPF (USA), SIN (Switzerland), and TRIUMF (Canada) and have been planned for use at new meson facilities under construction (USSR) and at proposed dedicated medical facilities. Providing therapeutically useful dose rates of pions requires a knowledge of the pion production cross sections as a function of primary proton energy (500 to 1000 MeV), pion energy (less than or equal to100 MeV), production angle, and target material. The current status of the data base in this area is presented including theoretical guidelines for extrapolation purposes. The target material and geometry, as well as the proton and pion beam parameters, will affect the electron (and muon) contamination in the beam which may have an important effect on both the LET characteristics of the dose and the dose distribution. In addition to cross-section data, channel characteristics such as length of pion trajectory, solid-angle acceptance, and momentum analysis will affect dose rate, distribution, and quality. Such considerations are briefly addressed in terms of existing facilities and proposed systems. 16 refs., 6 figs
Jet-like correlations with neutral pion triggers in pp and central Pb-Pb collisions at 2.76 TeV
Adam, Jaroslav; Aggarwal, Madan Mohan; Aglieri Rinella, Gianluca; Agnello, Michelangelo; Agrawal, Neelima; Ahammed, Zubayer; Ahmad, Shakeel; Ahn, Sang Un; Aiola, Salvatore; Akindinov, Alexander; Alam, Sk Noor; Silva De Albuquerque, Danilo; Aleksandrov, Dmitry; Alessandro, Bruno; Alexandre, Didier; Alfaro Molina, Jose Ruben; Alici, Andrea; Alkin, Anton; Alme, Johan; Alt, Torsten; Altinpinar, Sedat; Altsybeev, Igor; Alves Garcia Prado, Caio; An, Mangmang; Andrei, Cristian; Andrews, Harry Arthur; Andronic, Anton; Anguelov, Venelin; Anson, Christopher Daniel; Anticic, Tome; Antinori, Federico; Antonioli, Pietro; Aphecetche, Laurent Bernard; Appelshaeuser, Harald; Arcelli, Silvia; Arnaldi, Roberta; Arnold, Oliver Werner; Arsene, Ionut Cristian; Arslandok, Mesut; Audurier, Benjamin; Augustinus, Andre; Averbeck, Ralf Peter; Azmi, Mohd Danish; Badala, Angela; Baek, Yong Wook; Bagnasco, Stefano; Bailhache, Raphaelle Marie; Bala, Renu; Balasubramanian, Supraja; Baldisseri, Alberto; Baral, Rama Chandra; Barbano, Anastasia Maria; Barbera, Roberto; Barile, Francesco; Barnafoldi, Gergely Gabor; Barnby, Lee Stuart; Ramillien Barret, Valerie; Bartalini, Paolo; Barth, Klaus; Bartke, Jerzy Gustaw; Bartsch, Esther; Basile, Maurizio; Bastid, Nicole; Basu, Sumit; Bathen, Bastian; Batigne, Guillaume; Batista Camejo, Arianna; Batyunya, Boris; Batzing, Paul Christoph; Bearden, Ian Gardner; Beck, Hans; Bedda, Cristina; Behera, Nirbhay Kumar; Belikov, Iouri; Bellini, Francesca; Bello Martinez, Hector; Bellwied, Rene; Belmont Moreno, Ernesto; Espinoza Beltran, Lucina Gabriela; Belyaev, Vladimir; Bencedi, Gyula; Beole, Stefania; Berceanu, Ionela; Bercuci, Alexandru; Berdnikov, Yaroslav; Berenyi, Daniel; Bertens, Redmer Alexander; Berzano, Dario; Betev, Latchezar; Bhasin, Anju; Bhat, Inayat Rasool; Bhati, Ashok Kumar; Bhattacharjee, Buddhadeb; Bhom, Jihyun; Bianchi, Livio; Bianchi, Nicola; Bianchin, Chiara; Bielcik, Jaroslav; Bielcikova, Jana; Bilandzic, Ante; Biro, Gabor; Biswas, Rathijit; Biswas, Saikat; 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2016-12-10
We present measurements of two-particle correlations with neutral pion trigger particles of transverse momenta $8 3~\\mathrm{GeV}/c$, while with decreasing momenta an enhancement develops reaching about $5$ at low $p_{\\mathrm{T}}^{\\rm assoc}$. On the near side, an enhancement of $I_{\\mathrm{AA}}$ between $1.2$ at the highest to $1.8$ at the lowest $p_{\\mathrm{T}}^{\\rm assoc}$ is observed. The data are compared to parton-energy-loss predictions of the JEWEL and AMPT event generators, as well as to a perturbative QCD calculation with medium-modified fragmentation functions. All calculations qualitatively describe the away-side suppression at high $p_{\\mathrm{T}}^{\\rm assoc}$. Only AMPT captures the enhancement at low $p_{\\mathrm{T}}^{\\rm assoc}$, both on the near and away side. However, it also underpredicts $I_{\\mathrm{AA}}$ above $5$ GeV/$c$, in particular on the near-side.
Jet-like correlations with neutral pion triggers in pp and central Pb–Pb collisions at 2.76 TeV
Directory of Open Access Journals (Sweden)
J. Adam
2016-12-01
Full Text Available We present measurements of two-particle correlations with neutral pion trigger particles of transverse momenta 83 GeV/c, while with decreasing momenta an enhancement develops reaching about 5 at low pTassoc. On the near side, an enhancement of IAA between 1.2 at the highest to 1.8 at the lowest pTassoc is observed. The data are compared to parton-energy-loss predictions of the JEWEL and AMPT event generators, as well as to a perturbative QCD calculation with medium-modified fragmentation functions. All calculations qualitatively describe the away-side suppression at high pTassoc. Only AMPT captures the enhancement at low pTassoc, both on the near and away side. However, it also underpredicts IAA above 5 GeV/c, in particular on the near-side.
Pion-pion phase shifts from two loop chiral perturbation theory
International Nuclear Information System (INIS)
Borges, J. Sa; Barbosa, J. Soares; Tonasse, M.
1999-01-01
We present a two parameters fit of low energy P-wave shifts, using the recent published results of pion-pion scattering amplitudes from chiral perturbation theory, including two loops contributions. We show that, once given the P-wave, the isospin zero S-waves is in good agreement with experimental data. (author)
Measurement of inclusive production of neutral pions at high transverse momentum
International Nuclear Information System (INIS)
Ogawa, A.
1978-10-01
These are the results of a measurement of inclusive production at high transverse momentum (P perpendicular to) of neutral pions (π 0 ) from protons by beams of proton (p), kaon (K), pion (π), and antiproton (antiproton) particles. The experiment used the Fermilab M2 beam line at momenta of 100, 200 and 300 GeV/c striking a liquid hydrogen target. The data include center of mass (cm) production angles of the π 0 between 2 0 and 115 0 for P perpendicular to greater than 1 GeV/c. A pair of differential Cherenkov counters distinguished the types of beam particles. The photon (γ) detector of a lead and scintillator sandwich measured both photons from the π 0 → 2γ decay and enabled a reconstruction of the π 0 kinematics. The measurements show several remarkable features distinguishing the production rates for these different beams, including a forward peak in the cm for πp collisions and much less π 0 production at high P perpendicular to in pp than in πp or Kp collisions. A simple parametrization accurately represents the data over most of its range, showing approximate scaling in the radial variable x/sub R/ = 2P/√s (in the cm). Several parton models are compared with the data. A heuristic picture in terms of the quark constituents of the interacting hadrons accounts for many features of the data in an intuitive way. 62 references
Energy Technology Data Exchange (ETDEWEB)
Grimani, C.; Brunetti, M.T.; Codino, A. [Perugia Univ. (Italy)]|[INFN, Perugia (Italy); Papini, P.; Massimo Brancaccio, F.; Finetti, N. [Florence Univ. (Italy)]|[INFN, Florence (Italy); Stephens, S.A. [Tata Institute of Fundamental Researc, Bombay (International Commission on Radiation Units and Measurements); Basini, G.; Bongiorno, F. [INFN, Laboratori Nazionali di Frascati, Rome (Italy); Golden, R.L. [New Mexico State Univ. Las Cruces, NM (United States). Particle Astrophysics Lab.
1995-09-01
The fluxes of atmospheric electrons, positrons, positive and negative muons and negative pions have been determined using the NMSU Wizard-MASS2 balloons-borne instrument. The instrument was launched from Fort Sumner, New Mexico, (geomagnetic cut-off about 4.5 GV/c) on september 23, 1991. The flight lasted 9.8 hours and remained above 100.000 ft. Muons and negative pions were observed and their momenta were determined. Since these particles are not a part of the primary component, the measurement of their fluxes provides information regarding production and propagation of secondary particles in the atmosphere. Similarly, observations of electrons and positrons well below the geomagnetic cut-off provides insight into electromagnetic cascade processes in the upper atmosphere. In addition, the determination of the energy spectra of rare particles such as positrons can be used for background subtraction for cosmic ray experiments gathering data below a few g/cm{sup 2} of overlying atmosphere.
Elastic and inelastic pion reactions on few nucleon systems
Energy Technology Data Exchange (ETDEWEB)
Lensky, V.
2007-09-29
In the present work, we are studying elastic and inelastic pion reactions on few-body systems within the framework of chiral effective theory. We consider two specific reactions involving pions on few-nucleon systems, namely pion production in nucleon-nucleon collisions, and incoherent pion photoproduction on the deuteron. These two reactions are closely related to the issue of dispersive and absorptive corrections to the pion-deuteron scattering length, which we also consider in our analysis. The incoherent pion photoproduction is also considered as the possible source for a high-precision determination of the neutron-neutron scattering length. (orig.)
Elastic and inelastic pion reactions on few nucleon systems
International Nuclear Information System (INIS)
Lensky, V.
2007-01-01
In the present work, we are studying elastic and inelastic pion reactions on few-body systems within the framework of chiral effective theory. We consider two specific reactions involving pions on few-nucleon systems, namely pion production in nucleon-nucleon collisions, and incoherent pion photoproduction on the deuteron. These two reactions are closely related to the issue of dispersive and absorptive corrections to the pion-deuteron scattering length, which we also consider in our analysis. The incoherent pion photoproduction is also considered as the possible source for a high-precision determination of the neutron-neutron scattering length. (orig.)
Modification of pion pairs in nuclear matter; Modifikationen von Pionenpaaren in Kernmaterie
Energy Technology Data Exchange (ETDEWEB)
Gregor, Ralf
2007-07-18
In this work the quasifree photoproduction of pion pairs on bound nucleons is analyzed for the solid targets carbon, calcium and lead. These measurements allow an isospin dependent determination of the in medium properties of pion pairs. The invariant mass distributions showed a shift in strength towards the threshold region with increasing atomic number of the targets in case of an isoscalar {pi}{pi} meson system. According to theoretical predictions this effect was interpreted as a positive signature of a partial restoration of chiral symmetry. A pioneering experiment with photon beams was performed by the TAPS collaboration at the accelerator facility MAMI-B in Mainz in 1995. This measurement observed an invariant mass shift of the isoscalar {pi}{sup 0}{pi}{sup 0} channel with increasing atomic number. In the {pi}{sup {+-}}{pi}{sup 0} channel this effect was not observed. This observation confirmed the former experiments, since final state interactions of the pions would affect in first order both isospin channels in a similar way. Due to the poor statistics, the significance of the data was however limited. The experiment described in this work reached a much higher statistical significance, allowing a review of the old data and a study of the dependence of the signal from parameters like the momenta of the {pi}{pi} system or the single pions. In this experiment, the TAPS detector was used as a forward wall in combination with the Crystal Ball detector to achieve a 4{pi} solid angle coverage for photon detection at the MAMI accelerator facility. The new readout electronics for the BaF{sub 2} crystals was used for the first time. The new data analysis confirms the previously measured and published data. However, the shift of the invariant {pi}{sup 0}{pi}{sup 0} mass to the threshold region is less pronounced than in the published data. By performing cuts on the individual pion momenta, resulting in a maximum mean free path of the pions, the shift towards lower
Experiments on the nuclear interactions of pions and electrons
International Nuclear Information System (INIS)
Minehart, R.C.; Ziock, K.O.H.
1992-08-01
The analysis of the deuterium content in the CD target used in an experiment to study the π + d → 2p reaction at incident pion energies from 4 to 20 MeV was completed. The final paper describing this experiment will be submitted for publication this summer. Analysis of LAMPF Exp. on pion absorption in 4 He is continuing. In 1991, we collaborated with D. Pocanic from the Univ. of Virginia on a measurement at LAMPF of the π 0 production in π + p interactions. This run proved the validity of the method and additional data were obtained in a second run during the summer of 1992, using a new target. Current collaborations at LAMPF include the search for the decay μ + → e + + γ(MEGA) and a measurement of the Michel ρ parameter in the decay μ → e + v + v. A U.Va.--PSI collaboration is measuring pion beta decay to an accuracy of less than 1%, using a large acceptance CsI detector to measure the π 0 following decay of stopped π + mesons. Most of the U.Va. effort is devoted to the CEBAF Large Acceptance Spectrometer (CLAS) program to the construction of the CLAS forward calorimeter. An apparatus to measure the properties of the scintillators with light from a N 2 laser was built in the spring of 1992. The electronic circuitry for the energy signal from the EGN detector and the circuitry needed to route the signals from the all the photomultipliers to the TDC and ADC circuits are being developed. Experimental proposals for the study of electroproduction of nucleon resonances at CEBAF, including measurements with polarized beam and targets, are being developed
Low-energy photo- and electroproduction for physical pions
International Nuclear Information System (INIS)
MacMullen, J.T.
1979-02-01
The Ward identities of current algebra are combined with gauge invariance constraints, on-shell PCAC and the Bjorken limit to obtain the low-energy expressions of the pion photo- and electroproduction invariant amplitudes for physical pions
Asymptotics of Wigner 3nj-symbols with small and large angular momenta: an elementary method
International Nuclear Information System (INIS)
Bonzom, Valentin; Fleury, Pierre
2012-01-01
Yu and Littlejohn recently studied in (2011 Phys. Rev. A 83 052114 (arXiv:1104.1499)) some asymptotics of Wigner symbols with some small and large angular momenta. They found that in this regime the essential information is captured by the geometry of a tetrahedron, and gave new formulae for 9j-, 12j- and 15j-symbols. We present here an alternative derivation which leads to a simpler formula, based on the use of the Ponzano–Regge formula for the relevant tetrahedron. The approach is generalized to Wigner 3nj-symbols with some large and small angular momenta, where more than one tetrahedron are needed, leading to new asymptotics for Wigner 3nj-symbols. As an illustration, we present 15j-symbols with one, two and four small angular momenta, and give an alternative formula to Yu’s recent 15j-symbol with three small spins. (paper)
Chiral pion dynamics for spherical nucleon bags
International Nuclear Information System (INIS)
Vento, V.; Rho, M.; Nyman, E.M.; Jun, J.H.; Brown, G.E.; CEA Centre d'Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette
1980-01-01
A chirally symmetric quark-bag model for the nucleon is obtained by introducing an explicit, classical, pion field exterior to the bag. The coupling at the bag surface is determined by the requirement of a conserved axial-vector current. The pion field satisfies equations of motion corresponding to the non-linear sigma-model. We study on this paper the simplified case where the bag and the pion field are spherically symmetric. Corrections due to gluon exchange between the quarks are ignored along with other interactions which split the N- and Δ-masses. The equations of motion for the pion field are solved and we find a substantial pion pressure at the bag surface, along with an attractive contribution to the nucleon self-energy. The total energy of the system, bag plus meson cloud, turns out to be approximately Msub(n)c 2 for a wide range of bag radii, from 1.5 fm down to about 0.5 fm. Introduction of a form factor for the pion would extend the range of possible radii to even smaller values. We propose that the bag with the smallest allowed radius be identified with the 'little bag' discussed before. One surprising result of the paper is that as long as one restricts to spherically symmetric bags, restoring chiral symmetry to the bag model makes the axial-vector current coupling constant gsub(A) to be always too large compared with the experimental value for any bag radius, suggesting a deviation from spherical symmetry for the intrinsic bag wave functions of the 'ground-state' hadrons. (orig.)
Experimental study of the pion-xenon nucleus collisions at 3.5 GeV/c. Neutral pion production
International Nuclear Information System (INIS)
Strugalski, Z.; Abrosimov, A.T.; Wosinska, K.; Pawlak, T.; Nluta, J.; Sredniawa, B.; Il'ina, A.N.; Okhrimenko, L.S.; Peryt, W.; Miller, K.
1983-01-01
Experimental investigations of the neutral pion production are performed in pion-xenon collisions at 3.5 GeV/c. It is obtained that: 1) the average neutral pion multiplicity changes with the multiplicity of the protons emitted; 2) nearly 20% of the pions produced are emitted into the backward hemisphere; 3) the energy spectrum of the neutral pions is smooth; 4) the longitudinal component of the neutral pion momentum changes within the limits from -600 MeV/c to +1800 MeV/c; 5) the average value of the transversal component of the neutral pion momentum changes with the multiplicity of the protons emitted from approximately 270 to approximately 170 MeV/c; 6) the average value of the cosine of the neutral pion emission angle decreases with the multiplicity of the protons emitted
Capture and transfer of pions in hydrogenous materials
International Nuclear Information System (INIS)
Armstrong, D.S.
1990-05-01
Pionic hydrogen is a short-lived exotic hydrogen isotope in which a negative pion replaces the atomic electron. The formation and subsequent interactions of pionic hydrogen are discussed, with emphasis on the process of pion transfer. Recent results using the pion charge-exchange reaction (π - , π 0 ) obtained at TRIUMF are reviewed. (Author) (35 refs., 3 tabs., 9 figs.)
The pion form factor from analyticity and unitarity
Indian Academy of Sciences (India)
Analyticity and unitarity techniques are employed to estimate Taylor coefficients of the pion electromagnetic form factor at = 0 by exploiting the recently evaluated two-pion contribution to the muon ( − 2) and the phase of the pion electromagnetic form factor in the elastic region, known from scattering by ...
Funny hills in pion spectra from heavy-ion collisions
International Nuclear Information System (INIS)
Rasmussen, J.O.
1982-03-01
A discussion of some of the systematic features of the pion spectra in heavy-ions reactions is given. A discussion of the hills and valleys in heavy ion pion spectra that show up at the lower pion energies is given. The following topics are discussed: (1) three kinds of funny hills; (2) π - / + ratios near center of mass; (3) new Monte Carlo studies of charged pion spectra; and (4) pion orbiting about fireballs and Bose-Einstein behavior as explanation for the mid-rapidity P/sub perpendicular to/ approx. = 0.4 to 0.5 m/sub π/c hill
Exclusive electroproduction of two pions at HERA
Abramowicz, H.
2012-01-25
The exclusive electroproduction of two pions in the mass range 0.4 < M{\\pi}{\\pi} < 2.5 GeV has been studied with the ZEUS detector at HERA using an integrated luminosity of 82 pb-1. The analysis was carried out in the kinematic range of 2 < Q2 < 80 GeV2, 32 < W < 180 GeV and |t| < 0.6 GeV2, where Q2 is the photon virtuality, W is the photon-proton centre-of-mass energy and t is the squared four-momentum transfer at the proton vertex. The two-pion invariant-mass distribution is interpreted in terms of the pion electromagnetic form factor, |F(M{\\pi}{\\pi})|, assuming that the studied mass range includes the contributions of the {\\rho}, {\\rho}' and {\\rho}" vector-meson states. The masses and widths of the resonances were obtained and the Q2 dependence of the cross-section ratios {\\sigma}({\\rho}' \\rightarrow {\\pi}{\\pi})/{\\sigma}({\\rho}) and {\\sigma}({\\rho}" \\rightarrow {\\pi}{\\pi})/{\\sigma}({\\rho}) was extracted. The pion form factor obtained in the present analysis is compared to that obtained...
Study of giant resonances with pions
International Nuclear Information System (INIS)
Baer, H.W.
1984-01-01
Recent results on giant resonances obtained with pion-inelastic scattering and with single- and double-charge-exchange scattering are reviewed. The states discussed are isobaric analog states, double-isobaric analog states, and isovector L = 0, 1, and 2 collective states. 36 references
Exclusive electroproduction of two pions at HERA
Energy Technology Data Exchange (ETDEWEB)
Abramowicz, H.; Ashery, D.; Gueta, O.; Gurvich, E.; Ingbir, R.; Kananov, S.; Levy, A.; Stern, A. [Tel Aviv Univ., Raymond and Beverly Sackler Faculty of Exact Sciences, School of Physics, Tel Aviv (Israel); Abt, I.; Caldwell, A.; Reisert, B.; Schmidke, W.B. [Max-Planck-Institut fuer Physik, Muenchen (Germany); Adamczyk, L.; Bold, T.; Gach, G.; Grabowska-Bold, I.; Guzik, M.; Kisielewska, D.; Przybycien, M.; Suszycki, L. [AGH-Univ. of Science and Technology, Faculty of Physics and Applied Computer Science, Krakow (Poland); Adamus, M.; Plucinski, P.; Tymieniecka, T. [National Centre for Nuclear Research, Warsaw (Poland); Aggarwal, R.; Kaur, M.; Kaur, P.; Singh, I. [Panjab Univ., Dept. of Physics, Chandigarh (India); Antonelli, S.; Basile, M.; Bindi, M.; Cifarelli, L.; Contin, A.; De Pasquale, S.; Sartorelli, G.; Zichichi, A. [Univ. Bologna (Italy); INFN Bologna (Italy); Antonioli, P.; Bari, G.; Bellagamba, L.; Boscherini, D.; Bruni, A.; Bruni, G.; Cindolo, F.; Corradi, M.; Margotti, A.; Nania, R.; Polini, A. [INFN Bologna (Italy); Antonov, A.; Dolgoshein, B.A.; Gladkov, D.; Sosnovtsev, V.; Stifutkin, A.; Suchkov, S. [Moscow Engineering Physics Inst., Moscow (Russian Federation); Arneodo, M.; Ruspa, M. [Univ. del Piemonte Orientale, Novara, (Italy); INFN, Torino (Italy); Aushev, V.; Dolinska, G.; Gogota, O.; Korol, I.; Viazlo, O. [National Academy of Sciences, Inst. for Nuclear Research, Kyiv (Ukraine); National Taras Shevchenko Univ. of Kyiv, Dept. of Nuclear Physics, Kyiv (Ukraine); Aushev, Y.; Bartosik, N.; Bondarenko, K.; Kadenko, I.; Onishchuk, Yu.; Salii, A.; Tomalak, O.; Volynets, O.; Zolko, M. [National Taras Shevchenko Univ. of Kyiv, Dept. of Nuclear Physics, Kyiv (Ukraine); Bachynska, O.; Behnke, O.; Behr, J.; Behrens, U.; Blohm, C.; Borras, K.; Bot, D.; Ciesielski, R.; Coppola, N.; Fang, S.; Geiser, A.; Goettlicher, P.; Grebenyuk, J.; Gregor, I.; Haas, T.; Hain, W. [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany)] [and others
2012-01-15
The exclusive electroproduction of two pions in the mass range 0.4
Photoproduction of neutral pions off protons
Crede, V.; Sparks, N.; Wilson, A.; Anisovich, A. V.; Bacelar, J. C. S.; Bantes, R.; Bartholomy, O.; Bayadilov, D.; Beck, R.; Beloglazov, Y. A.; Castelijns, R.; Dutz, H.; Elsner, D.; Ewald, R.; Frommberger, F.; Funke, Chr; Gregor, R.; Gridnev, A.; Gutz, E.; Hillert, W.; Hoffmeister, P.; Jaegle, I.; Junkersfeld, J.; Kalinowsky, H.; Kammer, S.; Klein, Frank; Klein, Friedrich; Klempt, E.; Kotulla, M.; Krusche, B.; Löhner, H.; Lopatin, I. V.; Lugert, S.; Menze, D.; Mertens, T.; Messchendorp, J. G.; Metag, V.; Nanova, M.; Nikonov, V. A.; Novinski, D.; Novotny, R.; Ostrick, M.; Pant, L. M.; van Pee, H.; Pfeiffer, M.; Roy, A.; Sarantsev, A. V.; Schadmand, S.; Schmidt, C.; Schmieden, H.; Schoch, B.; Shende, S.; Sokhoyan, V.; Suele, A.; Sumachev, V. V.; Szczepanek, T.; Thoma, U.; Trnka, D.; Varma, R.; Walther, D.; Wendel, Ch
2011-01-01
Photoproduction of neutral pions has been studied with the CBELSA/TAPS detector in the reaction gamma p -> p pi(0) for photon energies between 0.85 and 2.50 GeV. The pi(0) mesons are observed in their dominant neutral decay mode: pi(0) -> gamma gamma. For the first time, the differential cross
Pion showers in highly granular calorimeters
Indian Academy of Sciences (India)
New results on properties of hadron showers created by pion beam at 8–80 GeV in high granular electromagnetic and hadron calorimeters are presented. Data were used for the ﬁrst time to investigate the separation of the neutral and charged hadron showers. The result is important to verify the prediction of the PFA ...
Nuclear potentials due to pion exchange
International Nuclear Information System (INIS)
Robillota, M.R.
1984-01-01
The two, three and four nucleon potentials due to the exchange of pions can be accurately calculated by means of chiral symmetry. The comparison of the dynamical content of these potentials allow us to understand the geometrical origin of the hierarchy existing among them. (Author) [pt
Investigation of pion-nucleus interactions
International Nuclear Information System (INIS)
Moore, C.F.
1992-09-01
This report summarizes the work carried out by personnel from the University of Texas at Austin at the Los Alamos Clinton P. Anderson Meson Physics Facility (LAMPF). The research activities involved experiments done with the Energetic Pion Channel and Spectrometer (EPICS), the Low Energy Pion Channel (LEP), the Pion and Particle Physics Channel (P 3 ), the High Resolution Spectrometer (HRS), and planning a new experimental program associated with the new high-resolution Neutral Meson Spectrometer (NMS) at LAMPF. A brief overview of work supported by this grant is given followed by an account of the study of the double giant resonances in pion double charge exchange on 51 V, 115 In, and 197 Au. This report contains a list of published papers and preprints, abstracts, and invited talks. These papers summarize experiments involving participants supported by this grant and indicate the work accomplished by these participants in this program of medium energy nuclear physics research. Lists of the most recent proposals on which we have participation at LAMPF, proposals which have been approved this past year to run as experiments, personnel who have participated in this research program are included. The research cited in this report is, in many cases, the collaborative effort of many groups associated with research at LAMPF
Exclusive electroproduction of two pions at HERA
International Nuclear Information System (INIS)
Abramowicz, H.; Ashery, D.; Gueta, O.; Gurvich, E.; Ingbir, R.; Kananov, S.; Levy, A.; Stern, A.
2012-01-01
The exclusive electroproduction of two pions in the mass range 0.4 ππ -1 . The analysis was carried out in the kinematic range of 2 2 2 , 32 2 , where Q 2 is the photon virtuality, W is the photon-proton centre-of-mass energy and t is the squared four-momentum transfer at the proton vertex. The two-pion invariant-mass distribution is interpreted in terms of the pion electromagnetic form factor, vertical stroke F(M ππ ) vertical stroke, assuming that the studied mass range includes the contributions of the ρ, ρ' and ρ'' vector-meson states. The masses and widths of the resonances were obtained and the Q 2 dependence of the cross-section ratios σ(ρ'→ππ)/ σ(ρ) and σ(ρ''→ππ)/ σ(ρ) was extracted. The pion form factor obtained in the present analysis is compared to that obtained in e + e - →π + π - . (orig.)
Exclusive electroproduction of two pions at HERA
Energy Technology Data Exchange (ETDEWEB)
Abramowicz, H. [Tel Aviv Univ. (Israel). School of Physics; Max Planck Institute for Physics, Munich (Germany); Abt, I. [Max Planck Institute for Physics, Munich (Germany); Adamczyk, L. [AGH-Univ. of Science and Technology, Krakow (PL). Faculty of Physics and Applied Computer Science] (and others)
2011-11-15
The exclusive electroproduction of two pions in the mass range 0.4< M{sub {pi}}{sub {pi}} <2.5 GeV has been studied with the ZEUS detector at HERA using an integrated luminosity of 82 pb{sup -1}. The analysis was carried out in the kinematic range of 2< Q{sup 2}<80 GeV{sup 2}, 32
Pion electromagnetic mass difference in QCD
International Nuclear Information System (INIS)
Margvelashvili, M.V.
1989-01-01
The results of currents algebra and the theory of partial conservation of axial currents the sum rules for the calculation of electromagnetic pion mass difference are developed. The procedure applied is suitable for other physical applications as it permits to calculate the integrals from different correlators with the assigned weight functions
Measurement of the Charged-Pion Polarizability
Adolph, C; Alexeev, M.G.; Alexeev, G.D.; Amoroso, A.; Andrieux, V.; Anosov, V.; Austregesilo, A.; Badelek, B.; Balestra, F.; Barth, J.; Baum, G.; Beck, R.; Bedfer, Y.; Berlin, A.; Bernhard, J.; Bicker, K.; Bieling, J.; Birsa, R.; Bisplinghoff, J.; Bodlak, M.; Boer, M.; Bordalo, P.; Bradamante, F.; Braun, C.; Bressan, A.; Buchele, M.; Burtin, E.; Capozza, L.; Chiosso, M.; Chung, S.U.; Cicuttin, A.; Colantoni, M.; Crespo, M.L.; Curiel, Q.; Dalla Torre, S.; Dasgupta, S.S.; Dasgupta, S.; Denisov, O.Yu.; Dinkelbach, A.M.; Donskov, S.V.; Doshita, N.; Duic, V.; Dunnweber, W.; Dziewiecki, M.; Efremov, A.; Elia, C.; Eversheim, P.D.; Eyrich, W.; Faessler, M.; Ferrero, A.; Filin, A.; Finger, M.; M. Finger jr; Fischer, H.; Franco, C.; von Hohenesche, N. du Fresne; Friedrich, J.M.; Frolov, V.; Gautheron, F.; Gavrichtchouk, O.P.; Gerassimov, S.; Geyer, R.; Gnesi, I.; Gobbo, B.; Goertz, S.; Gorzellik, M.; Grabmuller, S.; Grasso, A.; Grube, B.; Grussenmeyer, T.; Guskov, A.; Guthorl, T.; Haas, F.; von Harrach, D.; Hahne, D.; Hashimoto, R.; Heinsius, F.H.; Herrmann, F.; Hinterberger, F.; Hoppner, Ch.; Horikawa, N.; d'Hose, N.; Huber, S.; Ishimoto, S.; Ivanov, A.; Ivanshin, Yu.; Iwata, T.; Jahn, R.; Jary, V.; Jasinski, P.; Jorg, P.; Joosten, R.; Kabuss, E.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu. A.; Kisselev, Yu.; Klein, F.; Klimaszewski, K.; Koivuniemi, J.H.; Kolosov, V.N.; Kondo, K.; Konigsmann, K.; Konorov, I.; Konstantinov, V.F.; Kotzinian, A.M.; Kouznetsov, O.; Kramer, M.; Kroumchtein, Z.V.; Kuchinski, N.; Kuhn, R.; Kunne, F.; Kurek, K.; Kurjata, R.P.; Lednev, A.A.; Lehmann, A.; Levillain, M.; Levorato, S.; Lichtenstadt, J.; Maggiora, A.; Magnon, A.; Makke, N.; Mallot, G.K.; Marchand, C.; Martin, A.; Marzec, J.; Matousek, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G.; Meyer, W.; Michigami, T.; Mikhailov, Yu. V.; Miyachi, Y.; Moinester, M.A.; Nagaytsev, A.; Nagel, T.; Nerling, F.; Neubert, S.; Neyret, D.; Nikolaenko, V.I.; Novy, J.; Nowak, W.D.; Nunes, A.S.; Olshevsky, A.G.; Orlov, I.; Ostrick, M.; Panknin, R.; Panzieri, D.; Parsamyan, B.; Paul, S.; Peshekhonov, D.; Platchkov, S.; Pochodzalla, J.; Polyakov, V.A.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Regali, C.; Reicherz, G.; Rocco, E.; Rossiyskaya, N.S.; Ryabchikov, D.I.; Rychter, A.; Samoylenko, V.D.; Sandacz, A.; Sarkar, S.; Savin, I.A.; Sbrizzai, G.; Schiavon, P.; Schill, C.; Schluter, T.; Schmidt, K.; Schmieden, H.; Schonning, K.; Schopferer, S.; Schott, M.; Shevchenko, O.Yu.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Sosio, S.; Sozzi, F.; Srnka, A.; Steiger, L.; Stolarski, M.; Sulc, M.; Sulej, R.; Suzuki, H.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Takekawa, S.; Wolbeek, J. ter; Tessaro, S.; Tessarotto, F.; Thibaud, F.; Uhl, S.; Uman, I.; Virius, M.; Wang, L.; Weisrock, T.; Wilfert, M.; Windmolders, R.; Wollny, H.; Zaremba, K.; Zavertyaev, M.; Zemlyanichkina, E.; Ziembicki, M.; Zink, A.
2015-01-01
The COMPASS collaboration at CERN has investigated pion Compton scattering, $\\pi^-\\gamma\\rightarrow \\pi^-\\gamma$, at centre-of-mass energy below 3.5 pion masses. The process is embedded in the reaction $\\pi^-\\mathrm{Ni}\\rightarrow\\pi^-\\gamma\\;\\mathrm{Ni}$, which is initiated by 190 GeV pions impinging on a nickel target. The exchange of quasi-real photons is selected by isolating the sharp Coulomb peak observed at smallest momentum transfers, $Q^2<0.0015$ (GeV/$c$)$^2$. From a sample of 63 000 events the pion electric polarisability is determined to be $\\alpha_\\pi = (2.0 \\pm 0.6_{\\mbox{stat}} \\pm 0.7_{\\mbox{syst}}) \\times 10^{-4} \\mbox{fm}^3$ under the assumption $\\alpha_\\pi=-\\beta_\\pi$, which relates the electric and magnetic dipole polarisabilities. It is the most precise measurement of this fundamental low-energy parameter of strong interaction, that has been addressed since long by various methods with conflicting outcomes. While this result is in tension with previous dedicated measurements, it is fou...
Low energy scattering with a nontrivial pion
International Nuclear Information System (INIS)
Fariborz, Amir H.; Jora, Renata; Schechter, Joseph
2007-01-01
An earlier calculation in a generalized linear sigma model showed that the well-known current algebra formula for low energy pion-pion scattering held even though the massless Nambu Goldstone pion contained a small admixture of a two-quark two-antiquark field. Here we turn on the pion mass and note that the current algebra formula no longer holds exactly. We discuss this small deviation and also study the effects of a SU(3) symmetric quark mass type term on the masses and mixings of the eight SU(3) multiplets in the model. We calculate the s-wave scattering lengths, including the beyond current algebra theorem corrections due to the scalar mesons, and observe that the effect of the scalar mesons is to improve the agreement with experiment. In the process, we uncover the way in which linear sigma models give controlled corrections (due to the presence of scalar mesons) to the current algebra scattering formula. Such a feature is commonly thought to exist only in the nonlinear sigma model approach
Pion photoproduction in nucleons at low energies
International Nuclear Information System (INIS)
Carvalho, F.A.B.R. de.
1983-01-01
A new semiphenomenological analysis of the multipoles for pion photoproduction from nucleons, in the region of the first π-N resonance is presented. Through an energy dependent model, multipoles with isospin 1/2 and 3/2 and total angular momentum J [pt
PION-NUCLEON COUPLING-CONSTANT
STOKS,; TIMMERMANS, R; DESWART, JJ
In view of the persisting misunderstandings about the determination of the pion-nucleon coupling constants in the Nijmegen multienergy partial-wave analyses of pp, np, and ppBAR scattering data, we present additional information which may clarify several points of discussion. We comment on several
Effects of pions on normal tissues
International Nuclear Information System (INIS)
Tokita, N.
1981-01-01
Verification of the uniform biological effectiveness of pion beams of various dimensions produced at LAMPF has been made using cultured mammalian cells and mouse jejunum. Normal tissue radiobiology studies at LAMPF are reviewed with regard to biological beam characterization for the therapy program and the current status of acute and late effect studies on rodents
QCD coherence and correlations of particles with restricted momenta in hadronic Z decays
Abbiendi, G.; Akesson, P.F.; Alexander, G.; Anagnostou, G.; Anderson, K.J.; Asai, S.; Axen, D.; Bailey, I.; Barberio, E.; Barillari, T.; Barlow, R.J.; Batley, R.J.; Bechtle, P.; Behnke, T.; Bell, Kenneth Watson; Bell, P.J.; Bella, G.; Bellerive, A.; Benelli, G.; Bethke, S.; Biebel, O.; Boeriu, O.; Bock, P.; Boutemeur, M.; Braibant, S.; Brown, Robert M.; Burckhart, H.J.; Campana, S.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, D.G.; Ciocca, C.; Csilling, A.; Cuffiani, M.; Dado, S.; De Roeck, A.; De Wolf, E.A.; Desch, K.; Dienes, B.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Etzion, E.; Fabbri, F.; Ferrari, P.; Fiedler, F.; Fleck, I.; Ford, M.; Frey, A.; Gagnon, P.; Gary, John William; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Giunta, Marina; Goldberg, J.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gunther, P.O.; Gupta, A.; Hajdu, C.; Hamann, M.; Hanson, G.G.; Harel, A.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Herten, G.; Heuer, R.D.; Hill, J.C.; Horvath, D.; Igo-Kemenes, P.; Ishii, K.; Jeremie, H.; Jovanovic, P.; Junk, T.R.; Kanzaki, J.; Karlen, D.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kluth, S.; Kobayashi, T.; Kobel, M.; Komamiya, S.; Kramer, T.; Krasznahorkay, A., Jr.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kupper, M.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Lellouch, D.; Letts, J.; Levinson, L.; Lillich, J.; Lloyd, S.L.; Loebinger, F.K.; Lu, J.; Ludwig, A.; Ludwig, J.; Mader, W.; Marcellini, S.; Martin, A.J.; Mashimo, T.; Mattig, Peter; McKenna, J.; McPherson, R.A.; Meijers, F.; Menges, W.; Merritt, F.S.; Mes, H.; Meyer, Niels T.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mohr, W.; Mori, T.; Mutter, A.; Nagai, K.; Nakamura, I.; Nanjo, H.; Neal, H.A.; Nisius, R.; O'Neale, S.W.; Oh, A.; Oreglia, M.J.; Orito, S.; Pahl, C.; Pasztor, G.; Pater, J.R.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Pooth, O.; Przybycien, M.; Quadt, A.; Rabbertz, K.; Rembser, C.; Renkel, P.; Roney, J.M.; Rossi, A.M.; Rozen, Y.; Runge, K.; Sachs, K.; Saeki, T.; Sarkisyan, E.K.G.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schieck, J.; Schorner-Sadenius, T.; Schroder, Matthias; Schumacher, M.; Seuster, R.; Shears, T.G.; Shen, B.C.; Sherwood, P.; Skuja, A.; Smith, A.M.; Sobie, R.; Soldner-Rembold, S.; Spano, F.; Stahl, A.; Strom, David M.; Strohmer, R.; Tarem, S.; Tasevsky, M.; Teuscher, R.; Thomson, M.A.; Torrence, E.; Toya, D.; Tran, P.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Ujvari, B.; Vollmer, C.F.; Vannerem, P.; Vertesi, R.; Verzocchi, M.; Voss, H.; Vossebeld, J.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wilson, G.W.; Wilson, J.A.; Wolf, G.; Wyatt, T.R.; Yamashita, S.; Zer-Zion, D.; Zivkovic, Lidija
2006-01-01
QCD coherence effects are studied based on measurements of correlations of particles with either restricted transverse momenta, pT
International Nuclear Information System (INIS)
Akkelin, S.V.; Kobylinskij, N.A.; Martynov, E.S.
1989-01-01
A dual N-particle amplitude satisfying the quark counting rules for the processes with large transfer momenta is constructed. The multiparticle channels are shown to give an essential contribution to the amplitude decreasing power in a hard kinematic limit. 19 refs.; 9 figs
Measurement of rvec at signggd→pnπ0 at large nucleon momenta
International Nuclear Information System (INIS)
Adams, G.S.; Baghaei, H.; Caracappa, A.; Clayton, W.; D'Angelo, A.; Hoblit, S.; Khandaker, M.; Kistner, O.C.; Kobayashi, T.; Lindgren, R.; Miceli, L.; Ruth, C.; Sandorfi, A.M.; Schaerf, C.; Sealock, R.M.; Smith, L.C.; Stoler, P.; Tedeschi, D.J.; Thorn, C.E.; Thornton, S.T.; Vaziri, K.; Whisnant, C.S.; Winhold, E.J.
1995-01-01
Coincident protons and neutrons from the reaction rvec at signggd→pnπ 0 were measured at a photon energy of 290 MeV. Cross sections and beam asymmetries were extracted for nucleon momenta above the quasifree region for the first time. The measured cross sections are compared with the results of a cascade Monte Carlo calculation
Reaction mechanism and nuclear correlations study by low energy pion double charge exchange
International Nuclear Information System (INIS)
Weinfeld, Z.
1993-06-01
In pion double-charge-exchange (DCX) reactions, a positive (negative) pion is incident on a nucleus and a negative (positive) pion emerges. These reactions are of fundamental interest since the process must involve at least two nucleons in order to conserve charge. Although two nucleon processes are present in many reactions they are usually masked by the dominant single nucleon processes. DCX is unique in that respect since it is a two nucleon process in lowest order and thus may be sensitive to two-nucleon correlations. Measurements of low energy pion double-charge-exchange reactions to the double-isobaric-analog-state (DIAS) and ground-state (GS) of the residual nucleus provide new means for studying nucleon-nucleon correlations in nuclei. At low energies (T π 7/2 shell at energies ranging from 25 to 65 MeV. Cross sections were measured on 42,44,48 Ca, 46,50 Ti and 54 Fe. The calcium isotopes make a good set of nuclei on which to study the effects of correlations in DCX reactions
Ratio of Pion Kaon Production in Proton Carbon Interactions
Energy Technology Data Exchange (ETDEWEB)
Lebedev, Andrey V. [Harvard Univ., Cambridge, MA (United States)
2007-05-01
The ratio of pion-kaon production by 120 GeV/c protons incident on carbon target is presented. The data was recorded with the Main Injector Particle Production experiment at Fermi National Accelerator Laboratory. Production ratios of K^{+}/π^{+}, K^{-}/π^{-}, K^{-}/K^{+}, and π^{-}/π^{+} are measured in 24 bins in longitudinal momentum from 20 to 90 GeV/c and transverse momentum up to 2 GeV/c. The measurement is compared to existing data sets, particle production Monte Carlo results from FLUKA-06, parametrization of proton-beryllium data at 400/450 GeV/c, and ratios measured by the MINOS experiment on the NuMI target.
On mechanism of proton emission into the backward hemisphere in pion-carbon interactions at 5 GeV/c
International Nuclear Information System (INIS)
Abdinov, O.B.; Bajramov, A.A.; Budagov, Yu.A.; Valkar, Sh.; Dvornik, A.M.; Lomakin, Yu.F.; Flyagin, V.B.; Kharzheev, Yu.N.
1979-01-01
Experimental data on 11572 events of 5 GeV/c π - carbon interactions registered in the one-meter propane bubble chamber are analysed. The protons with 0.2< p<0.6 GeV/c momenta were chosen in the process of analysis. The momentum distributions of protons emitted into the backward hemisphere are compared with evaluations based on the cascade emission model. It is shown that the mechanism of nucleon rescattering in a nucleus, absorption of slow pions by a nucleon pair and disintegration of residual excited nucleus describe satisfactorily the process of high-energy hadron-nucleus interaction with proton emission in the backward hemisphere up to 5 GeV. The available data allow to single out some mechanisms choosing definite momentum and angle intervals
Alper, B; Booth, P; Bulos, F; Carroll, L J; Damgaard, G; Duff, Brian G; Heymann, Franz F; Jackson, J N; Jarlskog, G; Jönsson, L B; Klovning, A; Leistam, L; Lillethun, E; Lynch, G; Ølgaard-Nielsen, S; Prentice, M; Quarrie, D; von Dardel, Guy F; Weiss, J M
1973-01-01
The inclusive production of pi /sup +or-/ in proton-proton collisions has been measured for the transverse momentum range 0.15 to 1.0 GeV/c over an angular range of 29 degrees to 89 degrees in the centre-of- mass system and for centre-of-mass energies square root s=30.6 and 52.8 GeV. For each energy the invariant cross-section for fixed transverse momentum was found to increase by about 15% as the centre- of-mass rapidity decreases from 1 to 0, i.e. the 'central plateau' has not yet been reached. (8 refs).
Pion scattering to 8/sup -/ stretched states in /sup 60/Ni
Energy Technology Data Exchange (ETDEWEB)
Clausen, B.L.
1988-03-01
Using the Energetic Pion Channel and Spectrometer at the Los Alamos Meson Physics Facility, differential cross sections for pion scattering were measured for ten previously known J/sup ..pi../ = 8/sup /minus// stretched states in /sup 60/Ni. A possible new pure isoscalar stretched state was also found. The data were taken near the /DELTA//sub 3,3/-resonance using 162 MeV incident pions and scattering angles of 65/degree/, 80/degree/, and 90/degree/ for ..pi../sup +/ and 65/degree/ and 80/degree/ for ..pi../sup /minus//. The analysis of the /sup 60/Ni data found that the use of Woods-Saxon wave functions in the theoretical calculations gave much better agreement with data than the use of the usual harmonic oscillator wave functions. The WS theory gave better predictions of: the angle at which the ..pi../sup /minus// and ..pi../sup +/ angular distributions are maximum, the ratios of ..pi../sup /minus// to ..pi../sup +/ cross sections for pure isovector states (which were much larger than unity), and the absolute size of the cross sections for all states (so that the normalization factor necessary to arrive at agreement of theory with data was closer to unity). The theoretical calculations used the distorted wave impulse approximation, including new methods for unbound states. The sensitivities of the calculations to input parameters were investigated. This analysis using WS wave functions was extended to five other nuclei (/sup 12/C, /sup 14/C, /sup 16/O, /sup 28/Si, and /sup 54/Fe) on which both pion scattering and electron scattering have been done. A significant improvement in arriving at a normalization factor close to unity was found when WS wave functions were consistently used for analyzing both pion and electron inelastic scattering data. 101 refs., 26 figs., 13 tabs.
Pion source parameters in heavy ion collisions
International Nuclear Information System (INIS)
Crowe, K.M.; Bistirlich, J.A.; Bossingham, R.R.
1984-12-01
Following the early work of Goldhaber, Lee, and Pais, many experiments have used the momentum correlations between identical bosons to determine the space-time extent of the pion source for various reactions between elementary hadrons. This technique, known as intensity interferometry, has recently been applied to nuclear collisions at both intermediate and very high energies. Here we report on measurements of the radius and lifetime of the pion source in the reactions 1.8 A GeV 40 Ar + KCl → 2π/sup +-/ + X, 1.8 A GeV 20 Na + NaF → 2π - + X, and 1.71 A GeV 56 Fe + Fe → 2π - + X. 11 references
Pion contamination in the MICE muon beam
Bogomilov, M.; Vankova-Kirilova, G.; Bertoni, R.; Bonesini, M.; Chignoli, F.; Mazza, R.; Palladino, V.; de Bari, A.; Cecchet, G.; Capponi, M.; Iaciofano, A.; Orestano, D.; Pastore, F.; Tortora, L.; Kuno, Y.; Sakamoto, H.; Ishimoto, S.; Japan, Ibaraki; Filthaut, F.; Hansen, O.M.; Ramberger, S.; Vretenar, M.; Asfandiyarov, R.; Blondel, A.; Drielsma, F.; Karadzhov, Y.; Charnley, G.; Collomb, N.; Gallagher, A.; Grant, A.; Griffiths, S.; Hartnett, T.; Martlew, B.; Moss, A.; Muir, A.; Mullacrane, I.; Oates, A.; Owens, P.; Stokes, G.; Warburton, P.; White, C.; Adams, D.; Barclay, P.; Bayliss, V.; Bradshaw, T.W.; Courthold, M.; Francis, V.; Fry, L.; Hayler, T.; Hills, M.; Lintern, A.; Macwaters, C.; Nichols, A.; Preece, R.; Ricciardi, S.; Rogers, C.; Stanley, T.; Tarrant, J.; Watson, S.; Wilson, A.; Bayes, R.; Nugent, J.C.; Soler, F.J.P.; Cooke, P.; Gamet, R.; Alekou, A.; Apollonio, M.; Barber, G.; Colling, D.; Dobbs, A.; Dornan, P.; Hunt, C.; Lagrange, J-B.; Long, K.; Martyniak, J.; Middleton, S.; Pasternak, J.; Santos, E.; Savidge, T.; Uchida, M.A.; Blackmore, V.J.; Carlisle, T.; Cobb, J.H.; Lau, W.; Rayner, M.A.; Tunnell, C.D.; Booth, C.N.; Hodgson, P.; Langlands, J.; Nicholson, R.; Overton, E.; Robinson, M.; Smith, P.J.; Dick, A.; Ronald, K.; Speirs, D.; Whyte, C.G.; Young, A.; Boyd, S.; Franchini, P.; Greis, J.R.; Pidcott, C.; Taylor, I.; Gardener, R.; Kyberd, P.; Littlefield, M.; Nebrensky, J.J.; Bross, A.D.; Fitzpatrick, T.; Leonova, M.; Moretti, A.; Neuffer, D.; Popovic, M.; Rubinov, P.; Rucinski, R.; Roberts, T.J.; Bowring, D.; DeMello, A.; Gourlay, S.; Li, D.; Prestemon, S.; Virostek, S.; Zisman, M.; Drews, M.; Hanlet, P.; Kafka, G.; Kaplan, D.M.; Rajaram, D.; Snopok, P.; Torun, Y.; Winter, M.; Blot, S.; Kim, Y.K.; Bravar, U.; Onel, Y.; Cremaldi, L.M.; Hart, T.L.; Luo, T.; Sanders, D.A.; Summers, D.J.; Cline, D.; Yang, X.; Coney, L.; Hanson, G.G.; Heidt, C.
2016-01-01
The international Muon Ionization Cooling Experiment (MICE) will perform a systematic investigation of ionization cooling with muon beams of momentum between 140 and 240\\,MeV/c at the Rutherford Appleton Laboratory ISIS facility. The measurement of ionization cooling in MICE relies on the selection of a pure sample of muons that traverse the experiment. To make this selection, the MICE Muon Beam is designed to deliver a beam of muons with less than $\\sim$1\\% contamination. To make the final muon selection, MICE employs a particle-identification (PID) system upstream and downstream of the cooling cell. The PID system includes time-of-flight hodoscopes, threshold-Cherenkov counters and calorimetry. The upper limit for the pion contamination measured in this paper is $f_\\pi < 1.4\\%$ at 90\\% C.L., including systematic uncertainties. Therefore, the MICE Muon Beam is able to meet the stringent pion-contamination requirements of the study of ionization cooling.
Low-energy pion-nucleon scattering
International Nuclear Information System (INIS)
Gibbs, W.R.; Ai, L.; Kaufmann, W.B.
1998-01-01
An analysis of low-energy charged pion-nucleon data from recent π ± p experiments is presented. From the scattering lengths and the Goldberger-Miyazawa-Oehme (GMO) sum rule we find a value of the pion-nucleon coupling constant of f 2 =0.0756±0.0007. We also find, contrary to most previous analyses, that the scattering volumes for the P 31 and P 13 partial waves are equal, within errors, corresponding to a symmetry found in the Hamiltonian of many theories. For the potential models used, the amplitudes are extrapolated into the subthreshold region to estimate the value of the Σ term. Off-shell amplitudes are also provided. copyright 1998 The American Physical Society
Pion interactions at medium energies: Progress report
International Nuclear Information System (INIS)
Allred, J.C.; Goodman, C.
1970-01-01
Accelerating equipment, radiation detectors, and data acquisition equipment are described for a proposed study of 300 MeV pion scattering on deuterium targets at the Space Radiation Effects Laboratory in Newport News, Virginia. A key concept in the proposed program of measurements is a proposal by G.C Phillips to develop planes of proportional counters compatible with fast scintillation logic from pre-existing counters. The impetus for the research is the eventual use of the LAMPF accelerator at Los Alamos
Santos, Robenilson F; Bitencourt, Ana Carla P; Ragni, Mirco; Prudente, Frederico V; Coletti, Cecilia; Marzuoli, Annalisa; Aquilanti, Vincenzo
2017-04-01
The Wigner 9j symbols of the first kind-also known as Fano X-coefficients-serve to connect different addition schemes of four angular momenta, widely known examples being the LS and the jj couplings in atomic, molecular, and nuclear spectroscopies. Here, we also consider alternative sequences of binary couplings of four angular momenta, which are dealt through the 9j symbols of the second kind, and are explicitly given by the pentagonal (or Biedenharn-Elliott) identity. These coefficients are essential ingredients in the quantum-mechanical treatments of rotational and polarization phenomena in reaction dynamics and photoinduced processes. We also emphasize the combinatorial structure underlying the extended construction of a previously introduced truncated icosahedral "abacus", and provide extensions useful for algebraical manipulations, semiclassical interpretations, and computational applications, including all the 120 addition schemes.
An Overview of CC Coherent Pion Production
Williams, Zachary
2017-01-01
Neutrino cross-sections are a critical component to any neutrino measurement. With the modern neutrino experiments aiming to measure precision parameters, such as those in long-baseline oscillation experiments, the need for a detailed understanding of neutrino interactions has become even more important. Within this landscape remains a number of experimental challenges in the regime of low energy neutrino cross-sections. This talk will give an overview of recent publications on Charged Current-Coherent Pion Production (CC-Coh Pion) results from a number of experimental collaborations. Specifically, the lack of observation from the SciBooNE and T2K collaborations to observe CC-Coh Pion below one GeV in contrast to the observation of this signature at higher energies by other experiments. The work presented here is a part of the beginning steps to a reanalysis of the SciBooNE data using a modern neutrino generator in order to better understand the previous results. There will be included details of a liquid Argon purification system that is being built at UTA, and of plans for a ``Baby Time Projection Chamber (TPC)'' which will also be built at UTA, and the instrumentation and detector methods used in their construction. The closing is a look to the future for a new analysis at low neutrino energies utilizing Liquid Argon Time Projection Chambers (LArTPCs) based at Fermilab.
Weak pion production off the nucleon
International Nuclear Information System (INIS)
Hernandez, E.; Nieves, J.; Valverde, M.
2007-01-01
We develop a model for the weak pion production off the nucleon, which besides the delta pole mechanism [weak excitation of the Δ(1232) resonance and its subsequent decay into Nπ], includes also some background terms required by chiral symmetry. We refit the C 5 A (q 2 ) form factor to the flux-averaged ν μ p→μ - pπ + ANL q 2 -differential cross section data, finding a substantially smaller contribution of the delta pole mechanism than traditionally assumed in the literature. Within this scheme, we calculate several differential and integrated cross sections, including pion angular distributions, induced by neutrinos and antineutrinos and driven both by charged and neutral currents. In all cases we find that the background terms produce quite significant effects, and that they lead to an overall improved description of the data, as compared to the case where only the delta pole mechanism is considered. We also show that the interference between the delta pole and the background terms produces parity-violating contributions to the pion angular differential cross section, which are intimately linked to T-odd correlations in the contraction between the leptonic and hadronic tensors. However, these latter correlations do not imply a genuine violation of time-reversal invariance because of the existence of strong final state interaction effects
Pion momentum distributions in the nucleon in chiral effective theory
Energy Technology Data Exchange (ETDEWEB)
Burkardt, Matthias R. [New Mexico State U.; Hendricks, K. S. [North Carolina State U.; Ji, Cheung Ryong [North Carolina State U.; Melnitchouk, Wally [JLAB; Thomas, Anthony W. [Adelaide U.
2013-03-01
We compute the light-cone momentum distributions of pions in the nucleon in chiral effective theory using both pseudovector and pseudoscalar pion--nucleon couplings. For the pseudovector coupling we identify $\\delta$-function contributions associated with end-point singularities arising from the pion-nucleon rainbow diagrams, as well as from pion tadpole diagrams which are not present in the pseudoscalar model. Gauge invariance is demonstrated, to all orders in the pion mass, with the inclusion of Weinberg-Tomozawa couplings involving operator insertions at the $\\pi NN$ vertex. The results pave the way for phenomenological applications of pion cloud models that are manifestly consistent with the chiral symmetry properties of QCD.
Measurement of the charged-pion polarisability at COMPASS
CERN. Geneva
2015-01-01
For more than a decade, COMPASS has been tackling the measurement of the electromagnetic polarizability of the charged pion, which describes the stiffness of the pion against deformation in electromagnetic fields. Previous experiments date back to the 1980's in Serpukhov (Russia), where the Primakoff method for realizing interactions of charged pions with quasi-real photons was first employed. Later also other techniques in photon-nucleon and photon-photon collisions were carried out at different machines. The COMPASS measurement demonstrates that the charged-pion polarizability is significantly smaller than the previous results, roughly by a factor two, with the smallest uncertainties realized so far. The pion polarisability is of fundamental interest in the low-energy sector of quantum chromodynamics. It is directly linked to the quark-gluon substructure and dynamics of the pion, the lightest bound system of strong interaction.
Single pion electro- and neutrino production on heavy targets
International Nuclear Information System (INIS)
Paschos, E. A.; Schienbein, I.; Yu, J.Y.
2007-04-01
We present a calculation of single pion electroproduction cross sections on heavy targets in the kinematic region of the Δ(1232) resonance. Final state interactions of the pions are taken into account using the pion multiple scattering model of Adler, Nussinov and Paschos (ANP model). For electroproduction and neutral current reactions we obtain results for carbon, oxygen, argon and iron targets and find a significant reduction of the W-spectra for π 0 as compared to the free nucleon case. On the other hand, the charged pion spectra are only little affected by final state interactions. Measurements of such cross sections with the CLAS detector at JLAB could help to improve our understanding of pion rescattering effects and serve as important/valuable input for calculations of single pion neutrino production on heavy targets relevant for current and future long baseline neutrino experiments. Two ratios, in Eq. (3.8) and (3.10), will test important properties of the model. (authors)
An apparatus for the measurement of antiproton-proton cross sections at low momenta
International Nuclear Information System (INIS)
Brueckner, W.; Doebbeling, H.; Guettner, F.; Kneis, H.; Paul, S.; Povh, B.; Ransome, R.D.; Treichel, M.; Walcher, T.; Majewski, S.; Nomachi, M.; Shibata, T.A.
1988-01-01
An experiment which aims at a precise measurement of anti pp cross sections at low momenta is presented. Its design and performance are described with emphasis on the particle identification capabilities. A calorimeter-like detector array which serves for the detection of antineutrons is discussed in some detail. Its properties were measured in a test experiment and are compared to Monte Carlo calculations. (orig.)
[Measurements of observables of pion-nucleon reactions]. Progress report
International Nuclear Information System (INIS)
Sadler, M.E.
1985-01-01
This document reports the progress of the research of pion reactions. These include (1) a study to measure observables in the pion-nucleon system in the momentum interval 400 to 700 MeV/c, (2) differential cross section measurements at low energy for pion-nucleon charge exchange, and (3) elastic and inelastic scattering of π +- on 3 H and 3 He. Individual experiments will be indexed separately
International Nuclear Information System (INIS)
Armour, E.A.G.; Baker, D.J.; Plummer, M.
1990-01-01
Above incident energies of about 2 eV, the contribution to the total cross section in positron+H2 scattering from the sigma g+ symmetry is insufficient to account for the experimental value. Calculations carried out of the lowest partial waves of sigma u+ symmetry and Pion u symmetry using the Kohn variational method are described. The contributions to the total cross section from the two equivalent partial waves of Pion u symmetry significantly reduce the discrepancy with experiment up to incident energies of 4 to 5 eV. Comparisons are made with recent R-matrix calculations performed by Danby and Tennyson
International Nuclear Information System (INIS)
Hoeger, K.C.
1990-10-01
Higher-twist effects in point-like photon interactions on hydrogen have been studied in xF-distributions of charged particles for -0.2 2.0 GeV/c. Data were taken with a tagged photon beam with energies between 70 and 170 GeV and a pion/kaon beam at fixed energies of 80 and 140 GeV using the same setup of detectors at the CERN-Ω-spectrometer (WA69 experiment). The pion and kaon interactions were used to obtain an estimate of the hadron-like photon component. A first estimation of Higher-Twist cross sections in photoproduction of mesons at high pT has been obtained that is consistent with QCD-expectations. (orig.) [de
Nuclear transparencies from photoinduced pion production
Energy Technology Data Exchange (ETDEWEB)
W. Cosyn; M.C. Martinez; J. Ryckebusch; B. Van Overmeire
2006-12-01
We present a relativistic and cross-section factorized framework for computing nuclear transparencies extracted from A({gamma}, {pi} N) reactions at intermediate energies. The proposed quantum mechanical model adopts a relativistic extension to the multiple-scattering Glauber approximation to account for the final state interactions of the ejected nucleon and pion. The theoretical predictions are compared against the experimental {sup 4}He({gamma},p {pi}{sup -}) data from Jefferson Lab. For those data, our results show no conclusive evidence for the onset of mechanisms related to color transparency.
Rare kaon, muon, and pion decay
Energy Technology Data Exchange (ETDEWEB)
Littenberg, L.
1998-12-01
The author discusses the status of and prospects for the study of rare decays of kaons, muons, and pions. Studies of rare kaon decays are entering an interesting new phase wherein they can deliver important short-distance information. It should be possible to construct an alternative unitarity triangle to that determined in the B sector, and thus perform a critical check of the Standard Model by comparing the two. Rare muon decays are beginning to constrain supersymmetric models in a significant way, and future experiments should reach sensitivities which this kind of model must show effects, or become far less appealing.
Two-pion production in photon-induced reactions
Indian Academy of Sciences (India)
A deeper understanding of the situation is anticipated from a detailed experimental study of meson photoproduction from nuclei in exclusive reactions. In the energy regime above the (1232) resonance, the dominant double pion production channels are of particular interest. Double pion photoproduction from nuclei is ...
Pion interferometry theory for the hydrodynamic stage of multiple processes
International Nuclear Information System (INIS)
Makhlin, A.N.; Sinyukov, Yu.M.
1986-01-01
The double pion inclusive cross section for identical particles is described in hydrodynamical theory of multiparticle production. The pion interferometry theory is developed for the case when secondary particles are generated against the background of internal relativistic motion of radiative hadron matter. The connection between correlation functions in various schemes of experiment is found within the framework of relativistic Wigner functions formalism
Pion Electromagnetic Form Factor in Virtuality Distribution Formalism
Energy Technology Data Exchange (ETDEWEB)
Radyushkin, Anatoly V. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Old Dominion Univ., Norfolk, VA (United States)
2016-01-01
We discuss two applications of the {\\it Virtuality Distribution Amplitudes} (VDA) formalism developed in our recent papers. We start with an overview of the main properties of the pion distribution amplitude emphasizing the quantitative measures of its width, and possibility to access them through the pion transition form factor studies. We formulate the basic concepts of the VDA approach and introduce the pion {\\it transverse momentum distribution amplitude} (TMDA) which plays, in a covariant Lagrangian formulation, a role similar to that of the pion wave function in the 3-dimensional Hamiltonian light-front approach. We propose simple factorized models for soft TMDAs, and use them to describe existing data on the pion transition form factor, thus fixing the scale determining the size of the transverse-momentum effects. Finally, we apply the VDA approach to the one-gluon exchange contribution for the pion electromagnetic form factor. We observe a very late $Q^2 \\gtrsim 20$ GeV$^2$ onset of transition to the asymptotic pQCD predictions and show that in the $Q^2 \\lesssim 10$ GeV$^2$ region there is essentially no sensitivity to the shape of the pion distribution amplitude. Furthermore, the magnitude of the one-gluon exchange contribution in this region is estimated to be an order of magnitude below the Jefferson Lab data, thus leaving the Feynman mechanism as the only one relevant to the pion electromagnetic form factor behavior for accessible $Q^2$.
Experimental studies of pion-nucleus interactions at intermediate energies
International Nuclear Information System (INIS)
1991-01-01
This report summarizes the work on experimental research in intermediate energy nuclear physics carried out at New Mexico State University in 1991 under a great from the US Department of Energy. Most of these studies have involved investigations of various pion-nucleus interactions. The work has been carried out both with the LAMPF accelerator at the Los Alamos National Laboratory and with the cyclotron at the Paul Scherrer Institute (PSI) near Zurich, Switzerland. Part of the experimental work involves measurements of new data on double-charge-exchange scattering, using facilities at LAMPF which we helped modify, and on pion absorption, using a new detector system at PSI that covers nearly the full solid-angle region which we helped construct. Other work involved preparation for future experiments using polarized nuclear targets and a new high-resolution spectrometer system for detecting π 0 mesons. We also presented several proposals for works to be done in future years, involving studies related to pi-mesonic atoms, fundamental pion-nucleon interactions, studies of the difference between charged and neutral pion interactions with the nucleon, studies of the isospin structure of pion-nucleus interactions, and pion scattering from polarized 3 He targets. This work is aimed at improving our understanding of the pion-nucleon interaction, of the pion-nucleus interaction mechanism, and of nuclear structure
Pion production in high energy heavy ion collisions
International Nuclear Information System (INIS)
Wolf, K.L.; Bock, R.; Brockmann, R.
1984-01-01
Experimental data for heavy ion pion production reactions are compared with the predictions of a number of versions of cascade models. Pion suppression effects observed in the experimental data are fit by introducing refinements into cascade theory. Impact parameter adjustment, off-shell effects on the potential and perturbations due to nuclear matter are considered
Pion correlation from Skyrmion--anti-Skyrmion annihilation
International Nuclear Information System (INIS)
Lu, Y.; Amado, R.D.
1995-01-01
We study two pion correlations from Skyrmion and anti-Skyrmion collision, using the product ansatz and an approximate random grooming method for nucleon projection. The spatial-isospin coupling inherent in the Skyrme model, along with empirical averages, leads to correlations not only among pions of like charges but also among unlike charge types
Evolution of the LAMPF high power pion production target mechanisms
International Nuclear Information System (INIS)
Wilson, M.T.; Thorn, L.L.; Lindquist, L.O.; Grisham, D.L.
1977-01-01
The Los Alamos Clinton P. Anderson Meson Physics Facility's (LAMPF's) beam contains 800 kW of power and passes through three pion production targets in series before being deposited into an isotope production section and beam dump. The first two targets are rotating graphite rings that are radiatively cooled. The third pion production target is a water-cooled graphite slug
Processes involved in pion capture in hydrogen-containing molecules
International Nuclear Information System (INIS)
Horvath, D.
1983-03-01
A systematic analysis is presented of the possible elementary processes determining the fate of negative pions stopped in hydrogen-containing samples. Using a phenomenological description in comparison with the available experimental information on pion capture in hydrogen, it is shown that the formation and decay of pπ - atoms in compounds Zsub(m)Hsub(n) are determined mainly by the processes of Auger capture in a molecular orbit ZHπ - , transition from molecular to atomic orbit, transfer of pions to atoms Z in collisions pπ - +Z, and nuclear capture in collisions pπ - +H. The recent assumption of a considerable role of the processes of radiative atomic capture in bound hydrogen atoms, nuclear capture of pions by protons from the molecular state ZHπ - , or 'inner' transfer of the pion via tunnelling through the bond Z-H is not supported by the theory and contradicts the experimental data
Neutral pion production measurements at SciBooNE
International Nuclear Information System (INIS)
Catala-Perez, J.
2011-01-01
Neutrino-induced neutral pion production is an important measurement for next generation neutrino oscillation experiments. Neutral current (NC) neutral pion production is a direct background for electron neutrino appearance experiments, while charged current (CC) neutral pion production affects experiments looking for muon neutrino disappearance. Located in the Booster Neutrino Beam at Fermilab, SciBooNE is a neutrino scattering experiment designed to accurately measure muon neutrino and anti-neutrino cross sections on carbon near 1 GeV neutrino energy. In this talk I will present recent SciBooNE results on neutral pion production, including the total cross section measurement for both channels relative to the CC inclusive cross section, the separation of the coherent and incoherent contributions to the NC channel, and details on neutral pion production kinematics.
Pion-nucleus reactions in a microscopic transport model
International Nuclear Information System (INIS)
Engel, A.; Cassing, W.; Mosel, U.; Schaefer, M.; Wolf, G.
1994-01-01
We analyse pion-nucleus reactions in a microscopic transport model of the BUU type, which propagates nucleons, pions, deltas and N(1440) resonances explicitly in space and time. In particular we examine pion absorption and inelastic-scattering cross sections for pion kinetic energies T π =85-315 MeV and various target masses. In general, the mass dependence of the experimental data is well described for energies up to the Δ-resonance (∼160 MeV), while the absorption cross sections are somewhat overestimated for the higher energies. In addition we study the possible dynamical effects of delta and pion potentials in the medium on various observables as well as alternative models for the in-medium Δ-width. ((orig.))
Effective pion--nucleon interaction in nuclear matter
International Nuclear Information System (INIS)
Celenza, L.S.; Liu, L.C.; Nutt, W.; Shakin, C.M.
1976-01-01
We discuss the modification of the interaction between a pion and a nucleon in the presence of an infinite medium of nucleons (nuclear matter). The theory presented here is covariant and is relevant to the calculation of the pion--nucleus optical potential. The specific effects considered are the modifications of the nucleon propagator due to the Pauli principle and the modification of the pion and nucleon propagators due to collisions with nucleons of the medium. We also discuss in detail the pion self-energy in the medium, paying close attention to off-shell effects. These latter effects are particularly important because of the rapid variation with energy of the fundamental pion--nucleon interaction. Numerical results are presented, the main feature being the appearance of a significant damping width for the (3, 3) resonance
International Nuclear Information System (INIS)
Batishchev, Pavel A.; Tolstikhin, Oleg I.
2007-01-01
The Siegert pseudostate (SPS) formulation of scattering theory, originally developed by Tolstikhin, Ostrovsky, and Nakamura [Phys. Rev. A, 58, 2077 (1998)] for s-wave scattering in a spherically symmetric finite-range potential, is generalized to nonzero angular momenta. The orthogonality and completeness properties of SPSs are established and SPS expansions for the outgoing-wave Green's function, physical states, and scattering matrix are obtained. The present formulation completes the theory of SPSs in the one-channel case, making its application to three-dimensional problems possible. The results are illustrated by calculations for several model potentials
Analysis of prequilibrium two-particle correlations at large relative momenta
International Nuclear Information System (INIS)
Basrak, Z.; Ardouin, D.; Schuck, P.; Peghaire, A.; Sanit-Laurent, F.; Doubre, H.; Mittig, W.; Peter, J.; Yiyogi, Y.P.; Lynch, W.G.; Maier, M.
1990-01-01
This paper reports that both the polar and the azimuthal dependence of particle-particle correlation functions at large relative momenta are measured at 60 MeV/A for asymmetric (Ar + Au) and nearly symmetric (Ar + Ti) systems. The experimental data and dynamical simulations performed using the Landau-Vlasov semiclassical equation show persisting strong mean-field effects at 60 MeV/A. The general correlation-function pattern is perturbed via dissipative effects of nucleon-nucleon collisions. Theoretical studies are carried out also at lower energy (25 MeV/A) and compared with existing experimental data
Double charge exchange of pions on nuclei
International Nuclear Information System (INIS)
Dzhibuti, R.I.; Kezerashvili, R.Y.
1985-01-01
An analysis is made of the results of experimental and theoretical studies during the last ten years of a unique process: double charge exchange of pions on nuclei. On the one hand, the commissioning of meson factories and the use of new and more accurate experimental methods have led to the accumulation of rich and reliable material for not only light but also medium and heavy nuclei. On the other hand, the development and application of new microscopic theoretical approaches have led to a deepening of our ideas about the mechanism of these exotic reactions at low, intermediate, and high energies. The currently existing methods of theoretical investigation and all possible reaction mechanisms are considered. Particular attention is devoted to double charge exchange of pions on the lightest nuclei, for the theoretical description of which it is possible to use the well-developed methods for investigating few-particle systems. The experimental investigations of double-isobar analog and nonanalog transitions in the reaction of double charge exchange are systematized
Low energy pion-16O scattering
International Nuclear Information System (INIS)
Wafelbakker, C.K.
1981-01-01
In spite of some outward appearances, the modern microscopic theories of the pion-nucleus (πA) interaction are not fundamentally very different from each other. They can all be derived from the same source, multiple-scattering theory. They all treat the first-order optical potential in a comparatively detailed way and in all of them it is necessary to incorporate higher-order effects in general and pion-annihilation in particular phenomenologically. Basically the same physical features can be embodied in all of them. The presentation of the theoretical scheme underlying the present thesis is designed to stress this conceptual unity of current πA theory. In this thesis the methods developed by De Kam to incorporate Pauli- and binding-corrections to the impulse-approximation first-order optical potential for 4 He are extended to a more complicated nucleus, 16 O, for the first time. In concreto two situations are considered: π- 16 O scattering at energies below nucleon-knockout threshold (13.5 MeV) - 7 and 12 MeV - and at energies 40 and 49.7 MeV, above nucleon-knockout threshold but still well within the low-energy region. (Auth.)
Pion elastic scattering from polarized 13C in the energy region of the P33 resonance
International Nuclear Information System (INIS)
Yifen, Yen
1992-08-01
Asymmetries (A y ) and differential cross sections (dσ/dΩ) were measured for π + and π - elastic scattering using polarized and unpolarized 13 C targets. The experiment was done at the Los Alamos Meson Physics Facility with the pion beam from the Low Energy Pion channel. The scattered pions were detected with the Large Acceptance Spectrometer. The 13 C nuclei in 13 C-enriched 1-butanol were polarized by the dynamic nuclear polarilization method. Angular distributions of both A y and dσ/dΩ were measured below the P 33 resonance at the incident energy of 130 MeV for π + and π - , and above the resonance at 223 MeV for π + and at 226 MeV for π - . In addition, A y and dσ/dΩ were measured in a range of momentum transfers, 1.75 ≤ q ≤ 2.05 fm - , at several energies. At 130 MeV, the values of A y are significantly different from zero for π - scattering. For π + at 130 MeV and for both π - and π + at all other energies, the A y are mostly consistent with zero. Theoretical analyses were done using different nuclear structure models. The data were not reproduced by the presently available nuclear wave functions. It was found that the asymmetry is strongly sensitive to the quadrupole spin flip part of the transition. The data of this thesis complement measurements of the magnetic form factor from electron scattering. In attempts to fit both the asymmetry and the magnetic form factor, it was found that the pion asymmetry data are not reproduced by the wavefunctions which fit the magnetic form factor at low momentum transfers
MT2-reconstructed invisible momenta as spin analizers, and an application to top polarization
Guadagnoli, Diego
2014-01-01
Full event reconstruction is known to be challenging in cases with more than one undetected final-state particle, such as pair production of two states each decaying semi-invisibly. On the other hand, full event reconstruction would allow to access angular distributions sensitive to the spin fractions of the decaying particles, thereby dissecting their production mechanism. We explore this possibility in the case of Standard-Model t-tbar production followed by a leptonic decay of both W bosons, implying two undetected final-state neutrinos. We estimate the t and tbar momentum vectors event by event using information extracted from the kinematic variable MT2. The faithfulness of the estimated momenta to the true momenta is then tested in observables sensitive to top polarization and t-tbar spin correlations. Our method thereby provides a novel approach towards the evaluation of these observables, and towards testing t-tbar production beyond the level of the total cross section. While our discussion is confined...
Heavy mesons production study in the reaction antip + d → 3He+X at an incident energy of 1450 MeV
International Nuclear Information System (INIS)
Loireleux, E.
1990-02-01
Study of heavy meson production in the antip + d → 3 He + X reaction has been performed at the Laboratoire National Saturne synchrotron at 1450 MeV incident energy. The helium 3 particles have been detected by means of the SPES III spectrometer in an angular range between -0.2 0 and 21 0 and for momenta between 600 MeV/c and 1400 MeV/c. In the first part of this work, we give a summary of the different experimental and theoretical results already obtained on the subject during the last twenty years. The second part of this thesis is devoted to the description of the experimental set-up by which this experiment was conducted, that is the spectrometer, the two kinds of wires chambers, the trigger and the read-out electronics associated with each detector. The calibration of the different parts of the detection and the beam characteristics - intensity and polarization - is studied in the third part. There is also a discussion about the data reduction and then the extraction of results obtained with the help of two and three pion phase spaces simulations in the spectrometer. The results are presented in the last part of this work. The differential cross sections and the analyzing powers have been established for the centre of mass angles varying in step of 10 degrees for the mesons π 0 , η and ω. A conclusion which indicates the prospects for a near future closes this thesis [fr
Excitation functions of pion reactions on 14N, 16O, and 19F through the (3,3) resonance
International Nuclear Information System (INIS)
Jacob, N.P. Jr.; Markowitz, S.S.
1976-01-01
Cross sections for pion-induced reactions of the form (π,πN) and more complex spallation reactions of the form (π,X) have been measured from 50--550 MeV on the target nuclei 14 N, 16 O, and 19 F using the secondary pion beams at the Lawrence Berkeley Laboratory 184-inch synchrocyclotron and the Clinton P. Anderson Meson Physics Facility. The dominance of the (3,3) free-particle resonance is seen in all excitation functions determined in this work. Relative to the 12 C(π/sup plus-or-minus/,πN) 11 C reactions, the (π/sup plus-or-minus/,πN) reactions on 14 N, 16 O, and 19 F have magnitudes of 0.2, 1, and 0.7, respectively. The cross section ratio R=sigma (π - ,π - n)/sigma (π + ,π N) =1.68+-0.18 for 14 N at 188+-15 MeV, 1.68+-0.05 for 16 O at 188+-9 MeV, and 1.68+-0.03 for 19 F at 178+-2 MeV incident pion energy. The results from this work are compared to previous pion work, analogous proton-induced reactions, Monte Carlo intranuclear cascade-evaporation calculations, and to a semiclassical nucleon charge-exchange model which convincingly explains the (π,πN) reaction mechanism in the (3,3) resonance region
Pion double charge exchange on 16O at Tπ=300--500 MeV
International Nuclear Information System (INIS)
Beatty, D.P.; Burleson, G.R.; Rawool-Sullivan, M.; El-Ghossain, M.; Fortune, H.T.; Williams, A.L.; Smith, D.A.; Morris, C.L.; Garnett, R.; Watson, D.L.; Johnson, J.; Ward, H.; Whitley, C.; Matthews, S.K.; Palarczyk, M.; Edwards, C.; Espy, M.; Hashimoto, O.; Tomoyuki, H.
1993-01-01
Measurements of small-angle cross sections for the pion double-charge-exchange (DCX) reaction 16 O(π + ,π - ) 16 Ne (g.s.) at incident energies of 300--500 MeV are reported. These are the first measurements of DCX cross sections on a T=0 nucleus in this energy region. The behavior of the cross sections is similar to that of analog transitions, but they are smaller by more than an order of magnitude. This suggests sequential charge-exchange scattering as the dominant process, but suppressed by a mechanism not yet identified
Joint resummation for pion wave function and pion transition form factor
Energy Technology Data Exchange (ETDEWEB)
Li, Hsiang-nan [Institute of Physics, Academia Sinica,Academia Rd., Taipei, Taiwan 115 (China); Department of Physics, National Cheng-Kung University,University Rd., Tainan, Taiwan 701 (China); Department of Physics, National Tsing-Hua University,Kuang-Fu Rd., Hsinchu, Taiwan 300 (China); Shen, Yue-Long [College of Information Science and Engineering, Ocean University of China,Songling Rd, Qingdao, Shandong 266100 (China); Wang, Yu-Ming [Institut für Theoretische Teilchenphysik und Kosmologie RWTH Aachen,Physikzentrum Otto-Blumenthal-Straße, D-52056 Aachen (Germany); Physik Department T31, Technische Universität München,James-Franck-Straße, D-85748 Garching (Germany)
2014-01-03
We construct an evolution equation for the pion wave function in the k{sub T} factorization formalism, whose solution sums the mixed logarithm ln xln k{sub T} to all orders, with x (k{sub T}) being a parton momentum fraction (transverse momentum). This joint resummation induces strong suppression of the pion wave function in the small x and large b regions, b being the impact parameter conjugate to k{sub T}, and improves the applicability of perturbative QCD to hard exclusive processes. The above effect is similar to those from the conventional threshold resummation for the double logarithm ln{sup 2} x and the conventional k{sub T} resummation for ln{sup 2} k{sub T}. Combining the evolution equation for the hard kernel, we are able to organize all large logarithms in the γ{sup ∗}π{sup 0}→γ scattering, and to establish a scheme-independent k{sub T} factorization formula. It will be shown that the significance of next-to-leading-order contributions and saturation behaviors of this process at high energy differ from those under the conventional resummations. It implies that QCD logarithmic corrections to a process must be handled appropriately, before its data are used to extract a hadron wave function. Our predictions for the involved pion transition form factor, derived under the joint resummation and the input of a non-asymptotic pion wave function with the second Gegenbauer moment a{sub 2}=0.05, match reasonably well the CLEO, BaBar, and Belle data.
Neutrinos from PIon Beam Line, nuPIL
Energy Technology Data Exchange (ETDEWEB)
Lagrange, J. B. [Imperial Coll., London; Pasternak, J. [Imperial Coll., London; Bross, A. [Fermilab; Liu, A. [Fermilab
2016-05-05
LBNF-DUNE (Long Baseline Neutrino Facilities - Deep Underground Neutrino Experiment) is a project based at Fermilab to study neutrino oscillations. The current baseline regarding the neutrino production considers the conventional approach: a high energy proton beam hits a target, producing pions that are collected by a horn and that decay in a decay pipe. An alternative solution, called nuPIL (neutrinos from a Pion beam Line) consists of using a beam line to guide the pions to clean the beam and to put instrumentation to monitor it. This paper presents the concept and the first preliminary results.
Tensor polarization in pion-deuteron elastic scattering
Ungricht, E.; Freeman, W. S.; Geesaman, D. F.; Holt, R. J.; Specht, J. R.; Zeidman, B.; Stephenson, E. J.; Moses, J. D.; Farkhondeh, M.; Gilad, S.; Redwine, R. P.
1985-03-01
Angular distributions of the deuteron tensor polarization, t20, in π-d elastic scattering have been measured at pion energies of 180, 220, and 256 MeV. The experiment and analysis are described in detail. Theoretical calculations in which the effects of pion absorption on the elastic channel are small seem to reproduce the data. An excitation function was measured in order to search for a rap- id energy dependence of t20. No rapid angular or energy dependence was found near a pion energy of 134 MeV, where other experiments have suggested the existence of dibaryon resonances.
Universal pion freeze-out in heavy-ion collisions
Adamova, D; Appelshäuser, H; Belaga, V; Braun-Munzinger, P; Castillo, A; Cherlin, A; Damjanovic, S; Dietel, T; Dietrich, L; Drees, A; Esumi, S I; Filimonov, K; Fomenko, K; Fraenkel, Zeev; Garabatos, C; Glässel, P; Hering, G; Holeczek, J; Kushpil, V; Lenkeit, B C; Ludolphs, W; Maas, A; Marin, A; Milosevic, J; Milov, A; Miskowiec, D; Panebratsev, Yu A; Petchenova, O Yu; Petracek, V; Pfeiffer, A; Rak, J; Ravinovich, I; Rehak, P; Sako, H; Schükraft, Jürgen; Sedykh, S; Shimansky, S S; Slivova, J; Specht, H J; Stachel, J; Sumbera, M; Tilsner, H; Tserruya, Itzhak; Wessels, J P; Wienold, T; Windelband, B; Wurm, J P; Xie, W; Yurevich, S; Yurevich, V; Schmitz, W
2003-01-01
Based on an evaluation of recent systematic data on two-pion interferometry and on measured particle yields at mid-rapidity, we propose a universal condition for thermal freeze-out of pions in heavy-ion collisions. We show that freeze-out occurs when the mean free path of pions lambda_f reaches a value of approximately 2.5 fm, which is much smaller than the spatial extent of the system at freeze-out. This critical mean free path is independent of the centrality of the collision and its value is constant at all currently available beam energies from AGS to RHIC.
Soft pion theorem, asymptotic symmetry and new memory effect
Hamada, Yuta; Sugishita, Sotaro
2017-11-01
It is known that soft photon and graviton theorems can be regarded as the Ward-Takahashi identities of asymptotic symmetries. In this paper, we consider soft theorem for pions, i.e., Nambu-Goldstone bosons associated with a spontaneously broken axial symmetry. The soft pion theorem is written as the Ward-Takahashi identities of the S-matrix under asymptotic transformations. We investigate the asymptotic dynamics, and find that the conservation of charges generating the asymptotic transformations can be interpreted as a pion memory effect.
Single pion production in neutrino-nucleon interactions
Kabirnezhad, M.
2018-01-01
This work represents an extension of the single pion production model proposed by Rein [Z. Phys. C 35, 43 (1987)., 10.1007/BF01561054]. The model consists of resonant pion production and nonresonant background contributions coming from three Born diagrams in the helicity basis. The new work includes lepton mass effects, and nonresonance interaction is described by five diagrams based on a nonlinear σ model. This work provides a full kinematic description of single pion production in the neutrino-nucleon interactions, including resonant and nonresonant interactions in the helicity basis, in order to study the interference effect.
Forward pion-nucleon charge exchange reaction and Regge constraints
International Nuclear Information System (INIS)
Huang Fei; Sibirtsev, A.; Krewald, S.; Hanhart, C.; Haidenbauer, J.; Meibner, U.-G.
2009-01-01
We present our recent study of pion-nucleon charge exchange amplitudes above 2 GeV. We analyze the forward pion-nucleon charge exchange reaction data in a Regge model and compare the resulting amplitudes with those from the Karlsruhe-Helsinki and George-Washington-University partial-wave analyses. We explore possible high-energy constraints for theoretical baryon resonance analyses in the energy region above 2 GeV. Our results show that for the pion-nucleon charge exchange reaction, the appropriate energy region for matching meson-nucleon dynamics to diffractive scattering should be around 3 GeV for the helicity flip amplitude. (authors)
Dimunon production by pions and protons
International Nuclear Information System (INIS)
Weinstein, R.
1975-01-01
Dimuon production is reported for the reaction π - + Fe → μ + + μ - + anything at 200 GeV and p + Fe → μ + + μ - anything at 240 GeV. The X/sub L/ identical with P/sub L//P/sub Beam/ and P/sub perpendicular/ dependences of psi production are parameterized and fitted. For X/sub L/ greater than or equal to 0.5, the ratio of the psi production cross section for pions in iron to that for protons is found to be 7.4 +- 2. For the intermediate mass region, 1.2 less than or equal to M less than or equal to 2.5 GeV, preliminary results are given for X/sub L/, P/sub perpendicular/ and M/sub mu mu/ dependences
Systematics of pion double charge exchange
International Nuclear Information System (INIS)
Gilman, R.A.
1985-10-01
Differential cross sections have been measured for pion-induced double-charge-exchange (DCX) reactions leading to double-isobaric-analog states (DIAS) and low-lying nonanalog states in the residual nuclei. A description of the experimental details and data analysis is presented. The experimentally observed systematics of reactions leading to DIAS, to nonanalog ground states, and to low-lying 2 + states are described. Lowest-order optical-model calculations of DIAS DCX are compared to the data. Efforts to understand the anomalies by invoking additional reaction-mechanism amplitudes and a higher-order optical potential are described. Calculations of nonanalog DCX reactions leading to J/sup π/ = 0 + states were performed within a distorted-wave impulse-approximation framework. The sensitivities of these calculations to input parameters are discussed. 58 refs., 41 figs., 16 tabs
Systematics of pion double charge exchange
Energy Technology Data Exchange (ETDEWEB)
Gilman, R.A.
1985-10-01
Differential cross sections have been measured for pion-induced double-charge-exchange (DCX) reactions leading to double-isobaric-analog states (DIAS) and low-lying nonanalog states in the residual nuclei. A description of the experimental details and data analysis is presented. The experimentally observed systematics of reactions leading to DIAS, to nonanalog ground states, and to low-lying 2 states are described. Lowest-order optical-model calculations of DIAS DCX are compared to the data. Efforts to understand the anomalies by invoking additional reaction-mechanism amplitudes and a higher-order optical potential are described. Calculations of nonanalog DCX reactions leading to J/sup / = 0 states were performed within a distorted-wave impulse-approximation framework. The sensitivities of these calculations to input parameters are discussed. 58 refs., 41 figs., 16 tabs.
International Nuclear Information System (INIS)
Anon.
1987-01-01
In 1946, a band of intrepid physicists took a batch of a new kind of photographic emulsion up the Pic du Midi in the French Pyrenees to expose them to cosmic rays. After analysing the results at Bristol, C. M. G. Lattes, H. Muirhead, G. P. S. Occhialini and C. F. Powell were able to announce early the following year that they had seen the long-awaited pi meson, or pion, postulated by Yukawa in 1935 as the carrier of the strong nuclear force. This landmark discovery quickly revitalized particle physics after all its wartime upheavals. At the end of July, the H. H. Wills Physics Laboratory at Bristol was the scene of an unusual and memorable international conference to mark the 40th anniversary of this discovery
Double recharge of pions on a deuterium
International Nuclear Information System (INIS)
Nichitiu, F.; Falomkin, I.V.; Shcherbakov, Yu.A.
1987-01-01
Assumptions on the dibaryon nature of the existing narrow resonances below the threshold of the NΔ-state with masses 1935, 1965, 2015 MeV are considered. New proposals on construction of the particle systematics with a new particle (R-particle of mass 1025 MeV, J=1/2, T=3/2) are used to draw a conclusion that double charge exchange is possible on deuterium and helium-3 if dibaryons or new R-particles are born in the final state. Attention is paid to a possible decay of these particles through a weak channel. A search for double charge exchange of pions on hydrogen and deuterium using a laser-illuminated streamer chamber of high pressure is proposed
In-medium pion valence distributions in a light-front model
International Nuclear Information System (INIS)
Melo, J.P.B.C. de; Tsushima, K.; Ahmed, I.
2017-01-01
Pion valence distributions in nuclear medium and vacuum are studied in a light-front constituent quark model. The in-medium input for studying the pion properties is calculated by the quark-meson coupling model. We find that the in-medium pion valence distribution, as well as the in-medium pion valence wave function, are substantially modified at normal nuclear matter density, due to the reduction in the pion decay constant.
Pion and an improved static bag model
Energy Technology Data Exchange (ETDEWEB)
Donoghue, J.F.; Johnson, K.
1980-04-01
Quark-model calculations involve an extended static object localized in space. We introduce new methods, involving momentum-space wave packets, which account for this localization. These methods have little effect on heavy states, whose sizes are large compared to their Compton size 1/m, but are very important for light particles such as the pion. In this treatment the pion's mass is naturally very small, and, in order to connect with a spontaneously broken chiral symmetry, we require that m/sub ..pi../ vanish when the light quarks are massless. Expanding about this limit (and also readjusting the fit to other hadrons), we obtain m/sub q/=(m-italic/sub u/+m/sub d/)/2=33 MeV. We calculate F/sub ..pi../ approx. = 145 MeV (using a normalization such that F/sub ..pi../ vertical-bar /sub exp/=93 MeV), F/sub K//F/sub ..pi../ approx. = 1, and various corrections to static properties of baryons. In addition we explore the relationship of our methods with chiral perturbation theory, deriving the formula m/sub ..pi../ /sup 2/=(m-italic/sub u/+m/sub d/) < ..pi..(p) vertical-bar q-bar(0)q(0) vertical-bar ..pi..(p) > in the appropriate approximation and commenting on the quark mass obtained from the nucleon's sigma term. Finally we discuss the bag model's use of the scalar density q-barq as an order parameter describing the separation of the spontaneously broken vacuum phase from the perturbative vacuum of the bag's interior.
International Nuclear Information System (INIS)
Forozani, G.
2004-01-01
The magnitude of four independent amplitudes are obtained pion photoproduction in the energy range of 1300 to 2100 MeV incident photon. Different cross section and three polarization parameters are required for such amplitudes reconstruction at different pion scattering angles. Results of the direct amplitudes reconstruction have been compared with the solution of partial wave analysis SM95 and SM00K at all energies. This analysis indicates that we have a fair agreement between the present work and the results of partial wave analysis at many angles
International Nuclear Information System (INIS)
Forozani, G.
2004-01-01
The magnitude of four independent amplitudes are obtained in neutral pion photoproduction in the energy range of 1300 to 2100 MeV incident photon. Differential gross section and three polarization parameters are required for such amplitudes reconstruction at different pion scattering angles. Results of the direct amplitudes reconstruction have been compared with the solution of partial wave analysis SM95 and SM00K at all energies. This analysis indicates that we have a fair agreement between the present work and the results of partial wave analysis at meny angles (Author)
International Nuclear Information System (INIS)
Turck-Chieze, Sylvaine
1985-01-01
In this thesis, we present three exclusive electron scattering experiments on deuterium. Recoil neutron momenta from |n| = 0 to 500 MeV/c have been extracted from these measurements. In the first experiment, we studied the low recoil neutron momenta from |n| = 0 to 175 MeV/c in the quasi-elastic region. The second one is sensitive to the intermediate region from |n| = 155 to 335 MeV/c. The high momenta |n| =300 to 500 MeV/c were covered in the third kinematic condition range, in a more inelastic region influenced by pion exchange currents and isobar configuration. The S-wave component of the deuterium wave function has a minimum near 450 MeV/c, so the third measurement is mainly sensitive to the deuterium D-state and can provide a test of the nucleon-nucleon potential. The difficulty of these experiments comes from the small cross sections (≥ 15 pb/sr 2 /MeV) and the use of cryogenic liquid target whose density and dimension must be known accurately. The determination of the absolute values of the cross section is discussed in detail. The accuracy obtained was about 6 or 7 pc. The data from these experiments are compared to non-relativistic calculations of H. Arenhoevel and J.M. Laget which include electron interaction with the two nucleons, excitation states of the nucleon, proton neutron final state interaction and pionic exchange currents. These calculations are in good agreement with the first experiments for RSC potential. The agreement with Arenhoevel calculation is also good in the third one, but for this last experiment, a gauge invariance problem, coming certainly from the final state treatment, still remains in Laget's calculation. Data seem to favor the RSC or Paris nucleon nucleon potentials; 30 pc differences could be observed between their predictions and those given by the Bonn potentials. Nevertheless the study of the influence of the nucleon-nucleon potential can only be done in a complete relativistic calculation. (author) [fr
Effect of free-particle collisions in high energy proton and pion-induced nuclear reactions
International Nuclear Information System (INIS)
Jacob, N.P. Jr.
1975-07-01
The effect of free-particle collisions in simple ''knockout'' reactions of the form (a,aN) and in more complex nuclear reactions of the form (a,X) was investigated by using protons and pions. Cross sections for the 48 Ti(p,2p) 47 Sc and the 74 Ge(p,2p) 73 Ga reactions were measured from 0.3 to 4.6 GeV incident energy. The results indicate a rise in (p,2p) cross section for each reaction of about (25 +- 3) percent between the energies 0.3 and 1.0 GeV, and are correlated to a large increase in the total free-particle pp scattering cross sections over the same energy region. Results are compared to previous (p,2p) excitation functions in the GeV energy region and to (p,2p) cross section calculations based on a Monte Carlo intranuclear cascade-evaporation model. Cross section measurements for (π/sup +-/, πN) and other more complex pion-induced spallation reactions were measured for the light target nuclei 14 N, 16 O, and 19 F from 45 to 550 MeV incident pion energy. These measurements indicate a broad peak in the excitation functions for both (π,πN) and (π,X) reactions near 180 MeV incident energy. This corresponds to the large resonances observed in the free-particle π + p and π - p cross sections at the same energy. Striking differences in (π,πN) cross section magnitudes are observed among the light nuclei targets. The experimental cross section ratio sigma(π - ,π - n)/sigma(π + ,πN) at 180 MeV is 1.7 +- 0.2 for all three targets. The experimental results are compared to previous pion and analogous proton-induced reactions, to Monte Carlo intranuclear cascade-evaporation calculations, and to a semi-classical nucleon charge exchange model. (108 references) (auth)
On the role of secondary pions in spallation targets
Mancusi, Davide; Colonna, Nicola; Boudard, Alain; Cortés-Giraldo, Miguel Antonio; Cugnon, Joseph; David, Jean-Christophe; Leray, Sylvie; Lerendegui-Marco, Jorge; Massimi, Cristian; Vlachoudis, Vasilis
2017-01-01
We use particle-transport simulations to show that secondary pions play a crucial role for the development of the hadronic cascade and therefore for the production of neutrons and photons from thick spallation targets. In particular, for the n_TOF lead spallation target, irradiated with 20-GeV/c protons, neutral pions are involved in the production of ~90% of the high-energy photons; charged pions participate in ~40% of the integral neutron yield. Nevertheless, photon and neutron yields are shown to be relatively insensitive to large changes of the average pion multiplicity in the individual spallation reactions. We characterize this robustness as a peculiar property of hadronic cascades in thick targets.
The possibility for a pion polarizability measurement at COMPASS
Guskov, A
2010-01-01
The pion electromagnetic structure can be probed in $\\pi^{−}+(A,Z)\\rightarrow\\pi^{-}+(A,Z) + \\gamma$ Compton scattering in inverse kinematics (Primakoff reaction) and described by the electric $(\\alpha_{\\pi})$ and the magnetic $(\\beta_{\\pi})$ polarizabilities that depend on the rigidity of pion’s internal structure as a composite particle. Values for pion polarizabilities can be extracted from the comparison of the differential cross section for scattering of point-like pions with the measured cross section. The opportunity to measure pion polarizability via the Primakoff reaction at the COMPASS experiment was studied with a $\\pi^{−}$ beam of 190 GeV. The obtained results are used for preparation of the new measurement.
Deeply virtual compton scattering on a virtual pion target
Energy Technology Data Exchange (ETDEWEB)
Amrath, D.; Diehl, M. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Lansberg, J.P. [Ecole Polytechnique, 91 - Palaiseau (France). Centre de Physique Theorique]|[Heidelberg Univ. (Germany). Inst. fuer Theoretische Physik
2008-07-15
We study deeply virtual Compton scattering on a virtual pion that is emitted by a proton. Using a range of models for the generalized parton distributions of the pion, we evaluate the cross section, as well as the beam spin and beam charge asymmetries in the leading-twist approximation. Studying Compton scattering on the pion in suitable kinematics puts high demands on both beam energy and luminosity, and we find that the corresponding requirements will first be met after the energy upgrade at Jefferson Laboratory. As a by-product of our study, we construct a parameterization of pion generalized parton distributions that has a non-trivial interplay between the x and t dependence and is in good agreement with form factor data and lattice calculations. (orig.)
Proceedings of the LAMPF workshop on pion double charge exchange
International Nuclear Information System (INIS)
Baer, H.W.; Leitch, M.J.
1985-09-01
Experimental and theoretical aspects of double-analog, nonanalog, and continuum pion double charge exchange in the 50- to 310-MeV energy range are covered. Separate abstracts were prepared for 22 papers in these proceedings
Amplitude analysis of resonant production in three pions
Energy Technology Data Exchange (ETDEWEB)
Jackura, Andrew [Indiana Univ., Bloomington, IN (United States); Mikhasenko, Mikhail [Univ. of Bonn (Germany); Szczepaniak, Adam [Indiana Univ., Bloomington, IN (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
2016-11-29
We present some results on the analysis of three pion resonances. The analyses are motivated by the recent release of the largest data set on diffractively produced three pions by the COMPASS collaboration. We construct reaction amplitudes that satisfy fundamental $S$-matrix principles, which allows the use of models that have physical constraints to be used in fitting data. The models are motivated by the isobar model that satisfy unitarity constraints. The model consist of a Deck production amplitude with which final state interactions are constrained by unitarity. We employ the isobar model where two of the pions form a quasi-stable particle. The analysis is performed in the high-energy, single Regge limit. We specifically discuss the examples of the three pion $J^{PC}=2^{-+}$ resonance in the $\\rho\\pi$ and $f_2\\pi$ channels.
Roy-Steiner-equation analysis of pion-nucleon scattering
Meißner, U.-G.; Ruiz de Elvira, J.; Hoferichter, M.; Kubis, B.
2017-03-01
Low-energy pion-nucleon scattering is relevant for many areas in nuclear and hadronic physics, ranging from the scalar couplings of the nucleon to the long-range part of two-pion-exchange potentials and three-nucleon forces in Chiral Effective Field Theory. In this talk, we show how the fruitful combination of dispersion-theoretical methods, in particular in the form of Roy-Steiner equations, with modern high-precision data on hadronic atoms allows one to determine the pion-nucleon scattering amplitudes at low energies with unprecedented accuracy. Special attention will be paid to the extraction of the pion-nucleon σ-term, and we discuss in detail the current tension with recent lattice results, as well as the determination of the low-energy constants of chiral perturbation theory.
Pion interferometry of ultra-relativistic hadronic collisions
International Nuclear Information System (INIS)
Kolehmainen, K.
1986-05-01
Pion interferometry of ultra-relativistic hadronic collisions is described in the context of the inside-outside cascade model using a current ensemble method capable of describing an arbitrary distribution of pion sources with an arbitrary velocity distribution. The results are quite distinct from the usual Gaussian and Kopylov parameterizations. Extraction of the temperature parameter, effective source lifetime, and transverse size requires a full three-dimensional analysis of the correlation function in terms of the momentum difference. 7 refs., 4 figs
The TRIUMF low energy pion spectrometer and channel
International Nuclear Information System (INIS)
Sobie, R.J.; Drake, T.E.; Barnett, B.M.; Erdman, K.L.; Gyles, W.; Johnson, R.R.; Roser, H.W.; Tacik, R.; Blackmore, E.W.; Gill, D.R.
1983-08-01
A low energy pion spectrometer has been developed for use with the TRIUMF M13 pion channel. The combined channel and spectrometer resolution is presently 1.1 MeV at T = 50 MeV. This is limited by the amount of gas and detector material in the spectrometer in addition to the inherent resolution of the channel. Improvements to both the spectrometer and channel are discussed
Dosimetry and radiobiology of negative pions and heavy ions
International Nuclear Information System (INIS)
Raju, M.R.
1978-01-01
The depth dose distribution of pion beams has not been found superior to protons. Pion radiation quality at the plateau region is comparable to conventional low-LET radiations, and radiobiology results also indicate RBE values close to unity. In the pion stopping region, the radiation quality increases considerably. Radiobiology data for negative pions at the Bragg peak position clearly indicate the increase in RBE and the reduction in OER. Even at the Bragg peak position, compared to fast neutrons, the average LET of negative pions is lower. Pion radiobiology data have indicated lower RBE values and higher OER values compared to fast neutrons. The radiation quality of fast neutrons is in between that of carbon and neon ions at the peak region and that of neon ions at the plateau is lower than for fast neutrons. The mean LET value for helium ions, even at the distal end of the peak, is lower than for fast neutrons. Dose localization of heavy ions has been found to decrease slowly with increasing charge of the heavy ion. The intercellular contact that protects cells after exposure to low-LET radiations is not detected after exposure to heavy ions. Single and fractionated doses of heavy ions produce dose-response curves for heavy ions having reduced shoulders but similar slopes when compared to gamma rays. Fractionated treatments of heavy ions produce an enhanced effect in the peak region compared to the plateau region and could lead to a substantial gain in therapeutic ratio. The OER for protons was similar to that for x rays. The OER values for negative pions, helium ions, and carbon ions were larger, for neon ions similar, and for argon ions smaller when compared to fast neutrons.Negative pions, helium ions, and carbon ions may be very effective clinically because the radiation quality of these beams is similar to that of the mixed scheme of neutrons and x rays
Power corrections to the asymptotics of the pion electromagnetic formfactor
International Nuclear Information System (INIS)
Gorsky, A.S.
1984-01-01
The first power correction to the pion electromagnetic form factor is derived. A few asymptotic wave functions corresponding to the different series of operators and matrix elements of four-particle operators in pion have been found. The large scale of the first power correction approximately 10 2 (GeV 2 )/Q 2 where Q 2 is the momentum transfer indicates that at low energies the whole series of power corrections seems to be taken into account
Nuclear critical opalescence, a precursor to pion condensation
International Nuclear Information System (INIS)
Ericson, M.; Delorme, J.
1978-03-01
It is shown that pion condensation in nuclei, a long range phenomenon, has a precursor in the disordered phase, the local ordering of spins which becomes of infinite range at the critical point. A new physical effect arising from this short range order is predicted, namely the enhancement of the static nuclear pion field near the critical momentum. This phenomenon is strongly reminiscent of the critical opalescence observed in the scattering of neutrons by antiferromagnetic subtances
The Onset of Quark-Hadron Duality in Pion Electroproduction
Energy Technology Data Exchange (ETDEWEB)
Tigran Navasardyan; Gary Adams; Abdellah Ahmidouch; Tatiana Angelescu; John Arrington; Razmik Asaturyan; O. Baker; Nawal Benmouna; Crystal Bertoncini; Henk Blok; Werner Boeglin; Peter Bosted; Herbert Breuer; Michael Christy; Simon Connell; Yonggang Cui; Mark Dalton; Samuel Danagoulian; Donal Day; T. Dodario; James Dunne; Dipangkar Dutta; Najib Elkhayari; Rolf Ent; Howard Fenker; Valera Frolov; Liping Gan; David Gaskell; Kawtar Hafidi; Wendy Hinton; Roy Holt; Tanja Horn; Garth Huber; Ed Hungerford; Xiaodong Jiang; Mark Jones; Kyungseon Joo; Narbe Kalantarians; James Kelly; Cynthia Keppel; Edward Kinney; V. Kubarovski; Ya Li; Yongguang Liang; Simona Malace; Pete Markowitz; Erin McGrath; Daniella Mckee; David Meekins; Hamlet Mkrtchyan; Brian Moziak; Gabriel Niculescu; Maria-Ioana Niculescu; Allena Opper; Tanya Ostapenko; Paul Reimer; Joerg Reinhold; Julie Roche; Stephen Rock; Elaine Schulte; Edwin Segbefia; C. Smith; G.R. Smith; Paul Stoler; Vardan Tadevosyan; Liguang Tang; Maurizio Ungaro; Alicia Uzzle; Sandra Vidakovic; Anthony Villano; William Vulcan; Miao Wang; Glen Warren; Frank Wesselmann; Bogdan Wojtsekhowski; Stephen Wood; Chuncheng Xu; Lulin Yuan; Xiaochao Zheng; Hong Guo Zhu
2006-08-29
A large data set of charged-pion electroproduction from both hydrogen and deuterium targets has been obtained spanning the low-energy residual-mass region. These data conclusively show the onset of the quark-hadron duality phenomenon, as predicted for high-energy hadron electroproduction. We construct several ratios from these data to exhibit the relation of this phenomenon to the high-energy factorization ansatz of electron-quark scattering and subsequent quark-to- pion production mechanisms.
Asymptotical behaviour of pion electromagnetic form factor in QCD
International Nuclear Information System (INIS)
Efremov, A.V.; Radyushkin, A.V.
1978-01-01
In the framework of the renormalizable quantum field theory a new approach is developed to the investigation of asymptotical behaviour of two-particle bound state electromagnetic form factor. It is shown that the behaviour of the pion EM form factor in quantum chromodynamics at sufficiently large momentum transfers is controlled by the short-distance dynamics only. The formula is obtained which expresses the asymptotical behaviour of the pion form factor in terms of the fundamental constants of the theory
A relativistic, meson exchange model of pion-nucleon scattering
International Nuclear Information System (INIS)
Pearces, B.C.; Jennings, B.K.
1990-06-01
A relativistic meson exchange approach to the pion-nucleon interaction is developed using a three-dimensional relativistic two-body propagator, and the results using different propagators are compared. The relativistic approach is able to describe low energy scattering up to 400 MeV above threshold, while preserving the soft pion theorems. The different propagators give similar results, as the form factors necessary to get a fit suppress much of the multiple scattering. (Author) (24 refs., 4 tabs., 6 figs.)
Pion-nucleon vertex function with one nucleon off shell
International Nuclear Information System (INIS)
Mizutani, T.; Rochus, P.
1979-01-01
The pion-nucleon vertex function with an off-mass-shell nucleon is obtained through sideways dispersion relations with the P 11 and S 11 pion-nucleon phase shifts as only input. Contrary to the recent calculation of Nutt and Shakin, we find that the proper and improper vertex functions behave quite differently, indicating the importance of the nucleon propagator dressing. In particular the proper vertex function is found to have two poles in the unphysical region
Di-photon resonance and Dark Matter as heavy pions
Redi, Michele; Tesi, Andrea; Vigiani, Elena
2016-01-01
We analyse confining gauge theories where the 750 GeV di-photon resonance is a composite techni-pion that undergoes anomalous decays into SM vectors. These scenarios naturally contain accidentally stable techni-pions Dark Matter candidates. The di-photon resonance can acquire a larger width by decaying into Dark Matter through the CP-violating $\\theta$-term of the new gauge theory reproducing the cosmological Dark Matter density as thermal relic.
Di-photon resonance and Dark Matter as heavy pions
International Nuclear Information System (INIS)
Redi, Michele; Strumia, Alessandro; Tesi, Andrea; Vigiani, Elena
2016-01-01
We analyse confining gauge theories where the 750 GeV di-photon resonance is a composite techni-pion that undergoes anomalous decays into SM vectors. These scenarios naturally contain accidentally stable techni-pions Dark Matter candidates. The di-photon resonance can acquire a larger width by decaying into Dark Matter through the CP-violating θ-term of the new gauge theory reproducing the cosmological Dark Matter density as a thermal relic.
Pion transverse charge density from timelike form factor data
Energy Technology Data Exchange (ETDEWEB)
Gerald Miller, Mark Strikman, Christian Weiss
2011-01-01
The transverse charge density in the pion can be represented as a dispersion integral of the imaginary part of the pion form factor in the timelike region. This formulation incorporates information from e+e- annihilation experiments and allows one to reconstruct the transverse density much more accurately than from the spacelike pion form factor data alone. We calculate the transverse density using an empirical parametrization of the timelike pion form factor and estimate that it is determined to an accuracy of ~10% at a distance b ~ 0.1 fm, and significantly better at larger distances. The density is found to be close to that obtained from a zero-width rho meson pole over a wide range and shows a pronounced rise at small distances. The resulting two-dimensional image of the fast-moving pion can be interpreted in terms of its partonic structure in QCD. We argue that the singular behavior of the charge density at the center requires a substantial presence of pointlike configurations in the pion's partonic wave function, which can be probed in other high-momentum transfer processes.
International Nuclear Information System (INIS)
Boos, E.G.; Izbasarov, M.; Temiraliyev, T.; Samoilov, V.V.; Tursunov, R.A.
2005-01-01
Full text: The analysis has been undertaken for the energy ratio K π ± (partial coefficient of inelasticity) taken away by charged pions at laboratory coordinate system in pion-nucleon and pion-carbon interactions at momentum 40 GeV/s. It is shown that distribution of partial inelasticity coefficients for elementary act is more narrow than the same distribution for carbon nucleus. The mean number of charged mesons (n π ± t) grows with enlarging of partial inelasticity coefficient, being larger for interactions of π - -mesons with carbon nuclei in comparison with corresponding distribution in elementary act. The similar picture is observed for one-nucleon and multi-nucleon events selected from π - - C -interactions by the value of total electric charge of all secondary particles (except for the identified protons) and by the value of target mass
Energy Technology Data Exchange (ETDEWEB)
Chkhaidze, L.; Djobava, T.; Kharkhelauri, L. [High Energy Physics Institute of Tbilisi State University, Tbilisi (Georgia); Chlachidze, G. [Fermi National Accelerator Laboratory, Batavia, IL (United States); Galoyan, A. [Joint Institute for Nuclear Research, Veksler and Baldin Laboratory of High Energy Physics, Dubna (Russian Federation); Togoo, R. [Institute of Physics and Technology of the Mongolian Academy of Sciences, Ulan Bator (Mongolia); Uzhinsky, V. [Joint Institute for Nuclear Research, Laboratory of Information Technologies, Dubna (Russian Federation)
2016-11-15
Collective flows of protons and π{sup -}-mesons are studied at the momenta of 4.2, 4.5 and 10 AGeV/c for p+C, Ta and He+Li, C interactions. The data were obtained from the streamer chamber (SKM-200-GIBS) and from the Propane Bubble Chamber (PBC-500) systems utilized at JINR. A method of Danielewicz and Odyniec has been employed in determining a directed transverse flow of particles. The values of the transverse flow parameter and the strength of the anisotropic emission were defined for each interacting nuclear pair. It is found that the directed flows of protons and pions decrease with increasing the energy and the mass numbers of colliding nucleus pairs. The π{sup -}-meson and proton flows exhibit opposite directions in all studied interactions, and the flows of protons are directed in the reaction plane. The Ultra-relativistic Quantum Molecular Dynamical Model (UrQMD) coupled with the Statistical Multi-fragmentation Model (SMM), satisfactorily describes the obtained experimental results. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Ogawa, A.
1978-10-01
These are the results of a measurement of inclusive production at high transverse momentum (P perpendicular to) of neutral pions (..pi../sup 0/) from protons by beams of proton (p), kaon (K), pion (..pi..), and antiproton (antiproton) particles. The experiment used the Fermilab M2 beam line at momenta of 100, 200 and 300 GeV/c striking a liquid hydrogen target. The data include center of mass (cm) production angles of the ..pi../sup 0/ between 2/sup 0/ and 115/sup 0/ for P perpendicular to greater than 1 GeV/c. A pair of differential Cherenkov counters distinguished the types of beam particles. The photon (..gamma..) detector of a lead and scintillator sandwich measured both photons from the ..pi../sup 0/ ..-->.. 2..gamma.. decay and enabled a reconstruction of the ..pi../sup 0/ kinematics. The measurements show several remarkable features distinguishing the production rates for these different beams, including a forward peak in the cm for ..pi..p collisions and much less ..pi../sup 0/ production at high P perpendicular to in pp than in ..pi..p or Kp collisions. A simple parametrization accurately represents the data over most of its range, showing approximate scaling in the radial variable x/sub R/ = 2P/..sqrt..s (in the cm). Several parton models are compared with the data. A heuristic picture in terms of the quark constituents of the interacting hadrons accounts for many features of the data in an intuitive way. 62 references.
Pion inelastic scattering, pion photoproduction and inelastic electron scattering on light nuclei
International Nuclear Information System (INIS)
Ehramzhyan, R.A.
1985-01-01
Partial transitions in pion photoproduction reaction on 6 Li, 10 B, 12 C nuclei are considered. Particular stress is paied to simultaneous analysis both of (γ, π) ad (e, e'), (π, π') reactions. Such analysis is concretely ixemplified with the use of both phenomenological and microscopic approaches. Microscopic analysis is shown to give correct representation of reaction mechanism (γ, π), (e, e') and (π, π') at intermediate energies. Spin-isospin dipole resonances in 1p-shell nuclei are considered. It is shown that nuclear system excitation spectrum gross-structure is a result of resonance configuration splitting
Measurement of the neutral kaon regeneration amplitude in carbon at momenta below 1 GeV/c
Angelopoulos, Angelos; Aslanides, Elie; Backenstoss, Gerhard; Bargassa, P; Behnke, O; Benelli, A; Bertin, V; Blanc, F; Bloch, P; Carlson, P J; Carroll, M; Carvalho, J; Cawley, E; Charalambous, S; Chardin, G; Chertok, M B; Cody, A; Danielsson, M; Dejardin, M; Derré, J; Ealet, A; Eleftheriadis, C; Evangelou, I; Faravel, L; Ferreira-Marques, R; Fetscher, W; Fidecaro, Maria; Filipcic, A; Francis, D; Fry, J; Gabathuler, Erwin; Gamet, R; Garreta, D; Gerber, H J; Go, A; Haselden, A; Hayman, P J; Henry-Coüannier, F; Hollander, R W; Hubert, E; Jon-And, K; Kettle, P R; Kokkas, P; Kreuger, R; Le Gac, R; Leimgruber, F; Liolios, A; Machado, E; Mandic, I; Manthos, N; Marel, Gérard; Mikuz, M; Miller, J; Montanet, François; Müller, A; Nakada, Tatsuya; Pagels, B; Papadopoulos, I M; Pavlopoulos, P; Pinto da Cunha, J; Policarpo, Armando; Polivka, G; Rickenbach, R; Roberts, B L; Ruf, T; Sakelliou, L; Sanders, P; Schäfer, M; Schaller, L A; Schietinger, T; Schopper, A; Soares, A; Tauscher, Ludwig; Thibault, C; Touchard, F; Touramanis, C; Triantis, F A; Van Beveren, E; van Eijk, C W E; Vlachos, S; Weber, P; Wigger, I; Wolter, M; Yéche, C; Zavrtanik, D; Zimmerman, D
1997-01-01
The neutral kaon regeneration amplitude in carbon at momenta between 250 and 750~MeV/$c$ was determined by measuring the interference of inherent and coherently regenerated \\PKS\\ amplitudes. This interference appears in the rates of initially pure (tagged) \\PKz\\ and \\PaKz\\ decaying to \\Pgpp\\Pgpm\\ after crossing a carbon absorber.
Beam Spin Asymmetry Measurements for Two Pion Photoproduction at CLAS
Energy Technology Data Exchange (ETDEWEB)
Anderson, Mark D. [Univ. of Glasgow, Scotland (United Kingdom)
2015-09-01
The overarching goal of this analysis, and many like it, is to develop our understanding of the strong force interactions within the nucleon by examining the nature of their excitation spectra. As the resonances of these spectra have very short lifetimes (tau = 1x10^{-23} s) and often have very similar masses, it is often impossible to directly observe resonances in the excitation spectra of nucleons. Polarization observables allow us to study the resonances by looking at how they affect the spin state of final state particles. The beam asymmetry is a polarization observable that allows us to detect the sensitivity of these resonances, and other transition mechanisms, to the electric vector orientation of incident photons. Presented in this thesis are first measurements of the beam asymmetries in the resonant region for the reaction channel pgamma p --> p π^{+} π^{-}focusing on the intermediate mesonic states rho^0 and f^0, and the final state pions. The analysis used data from the g8b experiment undertaken at the Thomas Jefferson National Accelerator Facility (JLab), the first experiment at JLab to use a linearly polarized photon beam. Using the coherent Bremsstrahlung facility and the CLAS detector of Hall B at JLab allowed for many multi-channel reactions to be detected and the first measurements of many polarization observables including those presented here. A brief overview of the theoretical framework used to undertake this analysis is given, followed by a description of the experimental details of the facilities used, then a description of the calibration of the Bremsstrahlung tagging facility which the author undertook, and finally the analysis is presented and the resulting measurements.
Dynamical pion production via parametric resonance from disoriented chiral condensates
Hiro-Oka, Hideaki; Minakata, Hisakazu
2000-04-01
We discuss a dynamical mechanism of pion production from disoriented chiral condensates. It leads to an explosive production of pions via the parametric resonance mechanism, which is similar to the reheating mechanism in inflationary cosmology. Classically it is related with the instability in the solutions of the Mathieu equation and we explore the quantum aspects of the mechanism. We show that nonlinearities and back reactions can be ignorable for a sufficiently long time under the small amplitude approximations of background σ oscillations, which may be appropriate for the late stage of a nonequilibrium phase transition. It allows us to obtain an explicit quantum state of the produced pions and σ, the squeezed state of BCS type. Single particle distributions and two pion correlation functions are computed within these approximations. The results obtained illuminate the characteristic features of multipion states produced through the parametric amplification mechanism. In particular, two pion correlations of various charge combinations contain back-to-back correlations which cannot be masked by the identical particle interference effect. We suggest that the parametric resonance mechanism might be a cause of the long lasting amplification of low-momentum modes in linear sigma model simulations.
Distortion of two-pion interferometry by multipion correlations
International Nuclear Information System (INIS)
Zhang, W.N.; Liu, Y.M.; Wang, S.; Liu, Q.J.; Jiang, J.; Keane, D.; Shao, Y.; Chu, S.Y.; Fung, S.Y.
1993-01-01
Multipion correlations arising from the symmetrization of the n-pion wave function affect the extracted information from two-pion correlation measurements. The influence of multipion correlations on a sample of like-pion pairs can be expressed as a multipion correlation factor, the distribution of which offers good sensitivity to the multipion correlation effect. Analyses of the multipion correlation factor for two Bevalac streamer chamber data samples of 2.1A GeV Ne+Pb and 1.8A GeV Ar+Pb collisions show that the multipion correlation effect in the former sample is greater than in the latter. This result mainly arises from the fact that the pion source for Ne projectiles is smaller than for Ar projectiles. The residual correlations in the reference sample are related to the multipion correlation factor in multipion events, which can be expressed as a residual correlation factor. The influence of multipion correlations on two-pion interferometry analyses arises from the ratio of the residual correlation factor to the multipion correlation factor
Experimental study on pion capture by hydrogen bound in molecules
International Nuclear Information System (INIS)
Horvath, D.; Aniol, K.A.; Entezami, F.; Measday, D.F.; Noble, A.J.; Stanislaus, S.; Virtue, C.J.
1988-08-01
An experiment was performed at TRIUMF to study the formation of pionic hydrogen atoms and molecules in solids, particularly in groups of organic molecules of slightly different structure in order to help further clarify the problem. The nuclear capture of pions by hydrogen was measured using the charge exchange of stopped pions. The coincident photons emitted by the decaying π 0 mesons were detected by TRIUMF's two large NaI spectrometers. New experimental results were obtained for the capture probability of stopped π - mesons in the nuclei of hydrogen atoms, chemically bound in molecules of some simple hydrides, acid anhydrides, and sugar isomers. A linear relation was found between pion capture in hydrogen and melting point in sugar isomers. The pion capture probability in acid anhydrides is fairly well described by a simple atomic capture model in which the capture probability on the hydrogen dramatically increases as the hydrogen atom is separated from the strongly electronegative C 2 O 3 group. Both effects are consistent with a correlation between pion capture and electron density on hydrogen atoms. (Author) (38 refs., 4 tabs., 7 figs.)
Gauge invariance and the electromagnetic current of composite pions
International Nuclear Information System (INIS)
The Global Color-symmetry Model of QCD is extended to deal with a background electromagnetic field, and the associated conserved current is identified for the finite size bar qq pion modes at tree level. A well-defined truncation issued that factorizes the bilocal pion field into a local field variable and a hadronic form factor having a ladder Bethe-Salpeter content. The associated pion charge form factor is formulated. These developments are used to provide an illustration of how an effective hadronic action containing form factors may be electromagnetically coupled in a gauge invariant way that is accountable to its field substructure. In particular, the Ward-Takahashi identity for the photon vertex appropriate to the localized pion fields is seen to contain the hadronic form factors. In this context, gauge invariance of the effective hadronic action also requires recognition of the fact that the free inverse propagator for the localized pion field gauge transforms due to the substructure field content that has been absorbed into it
Sketching the pion's valence-quark generalised parton distribution
Directory of Open Access Journals (Sweden)
C. Mezrag
2015-02-01
Full Text Available In order to learn effectively from measurements of generalised parton distributions (GPDs, it is desirable to compute them using a framework that can potentially connect empirical information with basic features of the Standard Model. We sketch an approach to such computations, based upon a rainbow-ladder (RL truncation of QCD's Dyson–Schwinger equations and exemplified via the pion's valence dressed-quark GPD, Hπv(x,ξ,t. Our analysis focuses primarily on ξ=0, although we also capitalise on the symmetry-preserving nature of the RL truncation by connecting Hπv(x,ξ=±1,t with the pion's valence-quark parton distribution amplitude. We explain that the impulse-approximation used hitherto to define the pion's valence dressed-quark GPD is generally invalid owing to omission of contributions from the gluons which bind dressed-quarks into the pion. A simple correction enables us to identify a practicable improvement to the approximation for Hπv(x,0,t, expressed as the Radon transform of a single amplitude. Therewith we obtain results for Hπv(x,0,t and the associated impact-parameter dependent distribution, qπv(x,|b→⊥|, which provide a qualitatively sound picture of the pion's dressed-quark structure at a hadronic scale. We evolve the distributions to a scale ζ=2 GeV, so as to facilitate comparisons in future with results from experiment or other nonperturbative methods.
Chiral symmetry breaking and the pion quark structure
International Nuclear Information System (INIS)
Bernard, V.
1986-01-01
The mechanism of dynamical breaking of chiral symmetry in hadronic matter is first studied in the framework of the Nambu and Jona-Lasinio model on one hand and its generalisation to finite hadron size on the other hand. The analysis uses a variational procedure modelled after the BCS superconductor. Our study indicates for example, a great sensitivity of various quantities characterizing the breaking of symmetry to the shape of the interaction. Also the mechanism of breaking of chiral symmetry is essentially related to the mechanism of confinement. When a symmetry is spontaneously broken, there exists a Goldstone particle of zero mass. This is true in our model. This particle, the pion, is obtained as solution of a Bethe Salpeter equation for a qantiq bound state. This enables us to establish a connection between the pion as a Goldstone boson related to spontaneous symmetry breaking and the quark-antiquark structure of the pion. The finite mass of the physical pion is obtained with non zero current quark mass. Various properties of this particle are then studied in the RPA formalism. One important point of our model is the highly collective character of the pion. 85 refs [fr
Charged Pion Energy Reconstruction in the ATLAS Barrel Calorimeter
Bosman, Martine; Nessi, Marzio
1999-01-01
Intrinsic performance of the ATLAS calorimeters in the barrel region with respect to charged pions was studied. For this the following simulated data were used: pion energy scans ($E = 20, 50, 200, 400$ and $1000$ GeV) at two pseudo-rapidity points ($eta = 0.3$ and $1.3$) and pseudo-rapidity scans ($-0.2 < eta < 1.8$) with pions of constant transverse energy ($E_T = 20$ and $50$ GeV). For pion energy reconstruction the benchmark approach was used. Performance was estimated for cases, when energy and rapidity dependent and independent calibration parameters were applied. The best results were obtained with energy and rapidity dependent parameters. Studies done for pions enabled optimization of the cone size and of the cut to obtain the best energy resolution. Energy dependence of the resolution can be parameterized as: $(50pm4)%/sqrt{E} oplus (3.4pm0.3)% oplus 1.0/E$ at $eta = 0.3$ and $(68pm8)%/sqrt{E} oplus (3.0pm0.7)% oplus 1.5/E$ at $eta = 1.3$. Larger constant term at $eta=0.3$ can be explained by l...
Transverse linear and orbital angular momenta of beam waves and propagation in random media
Charnotskii, Mikhail
2018-01-01
For paraxial propagation of scalar waves, the classic electromagnetic theory definition of transverse linear (TLM) and orbital angular (OAM) momenta of the beam wave are represented in terms of the coherence function. We show in examples that neither is the presence of optical vortices necessary for the intrinsic OAM, nor does the presence of optical vortices warrant the non-zero intrinsic OAM. The OAM is analyzed for homogeneously coherent and twisted partially coherent beam waves. A twisted Gaussian beam has an intrinsic OAM with a per-unit power value that can be continuously changed by varying the twist parameters. Using the parabolic propagation equation for the coherence function, we show that both the total TLM and OAM are conserved for the free-space propagation, but not for propagation in an inhomogeneous medium. In the presence of the random inhomogeneous medium, the total TLM and OAM are conserved in average, but the OAM fluctuations grow with the propagation path. This growth is slower for beams with rotation-symmetric irradiance.
𝒩 = 2 supersymmetric harmonic oscillator: Basic brackets without canonical conjugate momenta
Srinivas, N.; Shukla, A.; Malik, R. P.
2015-09-01
We exploit the ideas of spin-statistics theorem, normal-ordering and the key concepts behind the symmetry principles to derive the canonical (anti)commutators for the case of a one (0 + 1)-dimensional (1D) 𝒩 = 2 supersymmetric (SUSY) harmonic oscillator (HO) without taking the help of the mathematical definition of canonical conjugate momenta with respect to the bosonic and fermionic variables of this toy model for the Hodge theory (where the continuous and discrete symmetries of the theory provide the physical realizations of the de Rham cohomological operators of differential geometry). In our present endeavor, it is the full set of continuous symmetries and their corresponding generators that lead to the derivation of basic (anti)commutators amongst the creation and annihilation operators that appear in the normal mode expansions of the dynamical fermionic and bosonic variables of our present 𝒩 = 2 SUSY theory of a HO. These basic brackets are in complete agreement with such kind of brackets that are derived from the standard canonical method of quantization scheme.
Multi-Lepton Production at High Transverse Momenta in ep Collisions at HERA
Aaron, F.D.; Andreev, V.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Bacchetta, A.; Backovic, S.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Beckingham, M.; Begzsuren, K.; Behnke, O.; Belousov, A.; Berger, N.; Bizot, J.C.; Boenig, M.-O.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Bruncko, D.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Cholewa, A.; Contreras, J.G.; Coughlan, J.A.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Daum, K.; Deak, M.; de Boer, Y.; Delcourt, B.; Del Degan, M.; Delvax, J.; De Roeck, A.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dossanov, A.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eliseev, A.; Elsen, E.; Essenov, S.; Falkiewicz, A.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Fleischer, M.; Fomenko, A.; Gabathuler, E.; Gayler, J.; Ghazaryan, Samvel; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gouzevitch, M.; Grab, C.; Greenshaw, T.; Grell, B.R.; Grindhammer, G.; Habib, S.; Haidt, D.; Hansson, M.; Helebrant, C.; Henderson, R.C.W.; Hennekemper, E.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Jacquet, M.; Janssen, M.E.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, Andreas Werner; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I.R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knutsson, A.; Kogler, R.; Korbel, V.; Kostka, P.; Kraemer, M.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Kutak, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Li, G.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lytkin, L.; Makankine, A.; Malinovski, E.; Marage, P.; Marti, Ll.; Martyn, H.-U.; Maxfield, S.J.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, Matthias Ulrich; Mudrinic, M.; Muller, K.; Murin, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, Paul R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nowak, K.; Nozicka, M.; Olivier, B.; Olsson, J.E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, Th.; Pascaud, C.; Patel, G.D.; Pejchal, O.; Peng, H.; Perez, E.; Petrukhin, A.; Picuric, I.; Piec, S.; Pitzl, D.; Placakyte, R.; Polifka, R.; Povh, B.; Preda, T.; Radescu, V.; Rahmat, A.J.; Raicevic, N.; Raspiareza, A.; Ravdandorj, T.; Reimer, P.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Ruiz Tabasco, J.E.; Rurikova, Z.; Rusakov, S.; Salek, D.; Salvaire, F.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R.N.; Sheviakov, I.; Shtarkov, L.N.; Shushkevich, S.; Sloan, T.; Smiljanic, Ivan; Smirnov, P.; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, Arnd E.; Staykova, Z.; Steder, M.; Stella, B.; Straumann, U.; Sunar, D.; Sykora, T.; Tchoulakov, V.; Thompson, G.; Thompson, P.D.; Toll, T.; Tomasz, F.; Tran, T.H.; Traynor, D.; Trinh, T.N.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Vinokurova, S.; Volchinski, V.; Wegener, D.; Wessels, M.; Wissing, Ch.; Wunsch, E.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y.C.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.
2008-01-01
Processes leading to a final state with at least two high transverse momentum leptons (electrons or muons) are studied using the full ep data sample collected by the H1 experiment at HERA. The data correspond to an integrated luminosity of 463 pb-1. Di-lepton and tri-lepton event classes are investigated. Cross sections of the production of e+e- and mu+mu- pairs are derived in a restricted phase space dominated by photon-photon collisions. In general, good agreement is found with Standard Model predictions. Events are observed with a total scalar sum of lepton transverse momenta above 100 GeV where the Standard Model expectation is low. In this region, combining di-lepton and tri-lepton classes, five events are observed in e+p collisions, compared to a Standard Model expectation of 0.96+-0.12, while no such event is observed in e-p data for 0.64+-0.09 expected.
Polarization-Dependent Measurements of Molecular Super Rotors with Oriented Angular Momenta
Murray, Matthew J.; Toro, Carlos; Liu, Qingnan; Mullin, Amy S.
2014-05-01
Controlling molecular motion would enable manipulation of energy flow between molecules. Here we have used an optical centrifuge to investigate energy transfer between molecular super rotors with oriented angular momenta. The polarizable electron cloud of the molecules interacts with the electric field of linearly polarized light that angularly accelerates over the time of the optical pulse. This process drives molecules into high angular momentum states that are oriented with the optical field and have energies far from equilibrium. High resolution transient IR spectroscopy reveals the dynamics of collisional energy transfer for these super excited rotors. The results of this study leads to a more fundamental understanding of energy balance in non-equilibrium environments and the physical and chemical properties of gases in a new regime of energy states. Results will be presented for several super rotor species including carbon monoxide, carbon dioxide, and acetylene. Polarization-dependent measurements reveal the extent to which the super rotors maintain spatial orientation of high angular momentum states.
Multi-lepton production at high transverse momenta in ep collisions at HERA
Energy Technology Data Exchange (ETDEWEB)
Aaron, F.D. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania)]|[Bucharest Univ. (Romania). Faculty of Physics; Alexa, C. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Andreev, V. [Lebedev Physical Institute, Moscow (RU)] (and others)
2008-06-15
Processes leading to a final state with at least two high transverse momentum leptons (electrons or muons) are studied using the full e{sup {+-}}p data sample collected by the H1 experiment at HERA. The data correspond to an integrated luminosity of 463 pb{sup -1}. Di-lepton and tri-lepton event classes are investigated. Cross sections of the production of e{sup +}e{sup -} and {mu}{sup +}{mu}{sup -}. pairs are derived in a restricted phase space dominated by photon-photon collisions. In general, good agreement is found with Standard Model predictions. Events are observed with a total scalar sum of lepton transverse momenta above 100 GeV where the Standard Model expectation is low. In this region, combining di-lepton and tri-lepton classes, five events are observed in e{sup +}p collisions, compared to a Standard Model expectation of 0.96{+-}0.12, while no such event is observed in e{sup -}p data for 0.64{+-}0.09 expected. (orig.)
Measurement of pion, kaon and proton production in proton-proton collisions at $\\sqrt{s}$ = 7 TeV
Adam, Jaroslav; Aggarwal, Madan Mohan; Aglieri Rinella, Gianluca; Agnello, Michelangelo; Agrawal, Neelima; Ahammed, Zubayer; Ahmed, Ijaz; Ahn, Sang Un; Aimo, Ilaria; Aiola, Salvatore; Ajaz, Muhammad; Akindinov, Alexander; Alam, Sk Noor; Aleksandrov, Dmitry; Alessandro, Bruno; Alexandre, Didier; Alfaro Molina, Jose Ruben; Alici, Andrea; Alkin, Anton; Alme, Johan; Alt, Torsten; Altinpinar, Sedat; Altsybeev, Igor; Alves Garcia Prado, Caio; Andrei, Cristian; Andronic, Anton; Anguelov, Venelin; Anielski, Jonas; Anticic, Tome; Antinori, Federico; Antonioli, Pietro; Aphecetche, Laurent Bernard; Appelshaeuser, Harald; Arcelli, Silvia; Armesto Perez, Nestor; Arnaldi, Roberta; Aronsson, Tomas; Arsene, Ionut Cristian; Arslandok, Mesut; Augustinus, Andre; Averbeck, Ralf Peter; Azmi, Mohd Danish; Bach, Matthias Jakob; Badala, Angela; Baek, Yong Wook; Bagnasco, Stefano; Bailhache, Raphaelle Marie; Bala, Renu; Baldisseri, Alberto; Ball, Markus; Baltasar Dos Santos Pedrosa, Fernando; Baral, Rama Chandra; Barbano, Anastasia Maria; Barbera, Roberto; Barile, Francesco; Barnafoldi, Gergely Gabor; Barnby, Lee Stuart; Ramillien Barret, Valerie; Bartalini, Paolo; Bartke, Jerzy Gustaw; Bartsch, Esther; Basile, Maurizio; Bastid, Nicole; Basu, Sumit; Bathen, Bastian; Batigne, Guillaume; Batista Camejo, Arianna; Batyunya, Boris; Batzing, Paul Christoph; Bearden, Ian Gardner; Beck, Hans; Bedda, Cristina; Behera, Nirbhay Kumar; Belikov, Iouri; Bellini, Francesca; Bello Martinez, Hector; Bellwied, Rene; Belmont Iii, Ronald John; Belmont Moreno, Ernesto; Belyaev, Vladimir; Bencedi, Gyula; Beole, Stefania; Berceanu, Ionela; Bercuci, Alexandru; Berdnikov, Yaroslav; Berenyi, Daniel; Bertens, Redmer Alexander; Berzano, Dario; Betev, Latchezar; Bhasin, Anju; Bhat, Inayat Rasool; Bhati, Ashok Kumar; Bhattacharjee, Buddhadeb; Bhom, Jihyun; Bianchi, Livio; Bianchi, Nicola; Bianchin, Chiara; Bielcik, Jaroslav; Bielcikova, Jana; Bilandzic, Ante; Biswas, Saikat; Bjelogrlic, Sandro; Blanco, Fernando; Blau, Dmitry; Blume, Christoph; Bock, Friederike; Bogdanov, Alexey; Boggild, Hans; Boldizsar, Laszlo; Bombara, Marek; Book, Julian Heinz; Borel, Herve; Borissov, Alexander; Borri, Marcello; Bossu, Francesco; Botje, Michiel; Botta, Elena; Boettger, Stefan; Braun-Munzinger, Peter; Bregant, Marco; Breitner, Timo Gunther; Broker, Theo Alexander; Browning, Tyler Allen; Broz, Michal; Brucken, Erik Jens; Bruna, Elena; Bruno, Giuseppe Eugenio; Budnikov, Dmitry; Buesching, Henner; Bufalino, Stefania; Buncic, Predrag; Busch, Oliver; Buthelezi, Edith Zinhle; Buxton, Jesse Thomas; Caffarri, Davide; Cai, Xu; Caines, Helen Louise; Calero Diaz, Liliet; Caliva, Alberto; Calvo Villar, Ernesto; Camerini, Paolo; Carena, Francesco; Carena, Wisla; Castillo Castellanos, Javier Ernesto; Castro, Andrew John; Casula, Ester Anna Rita; Cavicchioli, Costanza; Ceballos Sanchez, Cesar; Cepila, Jan; Cerello, Piergiorgio; Chang, Beomsu; Chapeland, Sylvain; Chartier, Marielle; Charvet, Jean-Luc Fernand; Chattopadhyay, Subhasis; Chattopadhyay, Sukalyan; Chelnokov, Volodymyr; Cherney, Michael Gerard; Cheshkov, Cvetan Valeriev; Cheynis, Brigitte; Chibante Barroso, Vasco Miguel; Dobrigkeit Chinellato, David; Chochula, Peter; Choi, Kyungeon; Chojnacki, Marek; Choudhury, Subikash; Christakoglou, Panagiotis; Christensen, Christian Holm; Christiansen, Peter; Chujo, Tatsuya; Chung, Suh-Urk; Cicalo, Corrado; Cifarelli, Luisa; Cindolo, Federico; Cleymans, Jean Willy Andre; Colamaria, Fabio Filippo; Colella, Domenico; Collu, Alberto; Colocci, Manuel; Conesa Balbastre, Gustavo; Conesa Del Valle, Zaida; Connors, Megan Elizabeth; Contreras Nuno, Jesus Guillermo; Cormier, Thomas Michael; Corrales Morales, Yasser; Cortes Maldonado, Ismael; Cortese, Pietro; Cosentino, Mauro Rogerio; Costa, Filippo; Crochet, Philippe; Cruz Albino, Rigoberto; Cuautle Flores, Eleazar; Cunqueiro Mendez, Leticia; Dahms, Torsten; Dainese, Andrea; Danu, Andrea; Das, Debasish; Das, Indranil; Das, Supriya; Dash, Ajay Kumar; Dash, Sadhana; De, Sudipan; De Caro, Annalisa; De Cataldo, Giacinto; De Cuveland, Jan; De Falco, Alessandro; De Gruttola, Daniele; De Marco, Nora; De Pasquale, Salvatore; Deisting, Alexander; Deloff, Andrzej; Denes, Ervin Sandor; D'Erasmo, Ginevra; Di Bari, Domenico; Di Mauro, Antonio; Di Nezza, Pasquale; Diaz Corchero, Miguel Angel; Dietel, Thomas; Dillenseger, Pascal; Divia, Roberto; Djuvsland, Oeystein; Dobrin, Alexandru Florin; Dobrowolski, Tadeusz Antoni; Domenicis Gimenez, Diogenes; Donigus, Benjamin; Dordic, Olja; Dubey, Anand Kumar; Dubla, Andrea; Ducroux, Laurent; Dupieux, Pascal; Ehlers Iii, Raymond James; Elia, Domenico; Engel, Heiko; Erazmus, Barbara Ewa; Erhardt, Filip; Eschweiler, Dominic; Espagnon, Bruno; Estienne, Magali Danielle; Esumi, Shinichi; Eum, Jongsik; Evans, David; Evdokimov, Sergey; Eyyubova, Gyulnara; Fabbietti, Laura; Fabris, Daniela; Faivre, Julien; Fantoni, Alessandra; Fasel, Markus; Feldkamp, Linus; Felea, Daniel; Feliciello, Alessandro; Feofilov, Grigorii; Ferencei, Jozef; Fernandez Tellez, Arturo; Gonzalez Ferreiro, Elena; Ferretti, Alessandro; Festanti, Andrea; Figiel, Jan; Araujo Silva Figueredo, Marcel; Filchagin, Sergey; Finogeev, Dmitry; Fionda, Fiorella; Fiore, Enrichetta Maria; Floris, Michele; Foertsch, Siegfried Valentin; Foka, Panagiota; Fokin, Sergey; Fragiacomo, Enrico; Francescon, Andrea; Frankenfeld, Ulrich Michael; Fuchs, Ulrich; Furget, Christophe; Furs, Artur; Fusco Girard, Mario; Gaardhoeje, Jens Joergen; Gagliardi, Martino; Gago Medina, Alberto Martin; Gallio, Mauro; Gangadharan, Dhevan Raja; Ganoti, Paraskevi; Gao, Chaosong; Garabatos Cuadrado, Jose; Garcia-Solis, Edmundo Javier; Gargiulo, Corrado; Gasik, Piotr Jan; Germain, Marie; Gheata, Andrei George; Gheata, Mihaela; Ghosh, Premomoy; Ghosh, Sanjay Kumar; Gianotti, Paola; Giubellino, Paolo; Giubilato, Piero; Gladysz-Dziadus, Ewa; Glassel, Peter; Gomez Ramirez, Andres; Gonzalez Zamora, Pedro; Gorbunov, Sergey; Gorlich, Lidia Maria; Gotovac, Sven; Grabski, Varlen; Graczykowski, Lukasz Kamil; Grelli, Alessandro; Grigoras, Alina Gabriela; Grigoras, Costin; Grigoryev, Vladislav; Grigoryan, Ara; Grigoryan, Smbat; Grynyov, Borys; Grion, Nevio; Grosse-Oetringhaus, Jan Fiete; Grossiord, Jean-Yves; Grosso, Raffaele; Guber, Fedor; Guernane, Rachid; Guerzoni, Barbara; Gulbrandsen, Kristjan Herlache; Gulkanyan, Hrant; Gunji, Taku; Gupta, Anik; Gupta, Ramni; Haake, Rudiger; Haaland, Oystein Senneset; Hadjidakis, Cynthia Marie; Haiduc, Maria; Hamagaki, Hideki; Hamar, Gergoe; Hanratty, Luke David; Hansen, Alexander; Harris, John William; Hartmann, Helvi; Harton, Austin Vincent; Hatzifotiadou, Despina; Hayashi, Shinichi; Heckel, Stefan Thomas; Heide, Markus Ansgar; Helstrup, Haavard; Herghelegiu, Andrei Ionut; Herrera Corral, Gerardo Antonio; Hess, Benjamin Andreas; Hetland, Kristin Fanebust; Hilden, Timo Eero; Hillemanns, Hartmut; Hippolyte, Boris; Hristov, Peter Zahariev; Huang, Meidana; Humanic, Thomas; Hussain, Nur; Hussain, Tahir; Hutter, Dirk; Hwang, Dae Sung; Ilkaev, Radiy; Ilkiv, Iryna; Inaba, Motoi; Ionita, Costin; Ippolitov, Mikhail; Irfan, Muhammad; Ivanov, Marian; Ivanov, Vladimir; Izucheev, Vladimir; Jacobs, Peter Martin; Jahnke, Cristiane; Jang, Haeng Jin; Janik, Malgorzata Anna; Pahula Hewage, Sandun; Jena, Chitrasen; Jena, Satyajit; Jimenez Bustamante, Raul Tonatiuh; Jones, Peter Graham; Jung, Hyungtaik; Jusko, Anton; Kadyshevskiy, Vladimir; Kalinak, Peter; Kalweit, Alexander Philipp; Kamin, Jason Adrian; Kang, Ju Hwan; Kaplin, Vladimir; Kar, Somnath; Karasu Uysal, Ayben; Karavichev, Oleg; Karavicheva, Tatiana; Karpechev, Evgeny; Kebschull, Udo Wolfgang; Keidel, Ralf; Keijdener, Darius Laurens; Keil, Markus; Khan, Kamal; Khan, Mohammed Mohisin; Khan, Palash; Khan, Shuaib Ahmad; Khanzadeev, Alexei; Kharlov, Yury; Kileng, Bjarte; Kim, Beomkyu; Kim, Do Won; Kim, Dong Jo; Kim, Hyeonjoong; Kim, Jinsook; Kim, Mimae; Kim, Minwoo; Kim, Se Yong; Kim, Taesoo; Kirsch, Stefan; Kisel, Ivan; Kiselev, Sergey; Kisiel, Adam Ryszard; Kiss, Gabor; Klay, Jennifer Lynn; Klein, Carsten; Klein, Jochen; Klein-Boesing, Christian; Kluge, Alexander; Knichel, Michael Linus; Knospe, Anders Garritt; Kobayashi, Taiyo; Kobdaj, Chinorat; Kofarago, Monika; Kohler, Markus Konrad; Kollegger, Thorsten; Kolozhvari, Anatoly; Kondratev, Valerii; Kondratyeva, Natalia; Kondratyuk, Evgeny; Konevskikh, Artem; Kouzinopoulos, Charalampos; Kovalenko, Oleksandr; Kovalenko, Vladimir; Kowalski, Marek; Kox, Serge; Koyithatta Meethaleveedu, Greeshma; Kral, Jiri; Kralik, Ivan; Kravcakova, Adela; Krelina, Michal; Kretz, Matthias; Krivda, Marian; Krizek, Filip; Kryshen, Evgeny; Krzewicki, Mikolaj; Kubera, Andrew Michael; Kucera, Vit; Kucheryaev, Yury; Kugathasan, Thanushan; Kuhn, Christian Claude; Kuijer, Paulus Gerardus; Kulakov, Igor; Kumar, Jitendra; Kurashvili, Podist; Kurepin, Alexander; Kurepin, Alexey; Kuryakin, Alexey; Kushpil, Svetlana; Kweon, Min Jung; Kwon, Youngil; La Pointe, Sarah Louise; La Rocca, Paola; Lagana Fernandes, Caio; Lakomov, Igor; Langoy, Rune; Lara Martinez, Camilo Ernesto; Lardeux, Antoine Xavier; Lattuca, Alessandra; Laudi, Elisa; Lea, Ramona; Leardini, Lucia; Lee, Graham Richard; Lee, Seongjoo; Legrand, Iosif; Lehnert, Joerg Walter; Lemmon, Roy Crawford; Lenti, Vito; Leogrande, Emilia; Leon Monzon, Ildefonso; Leoncino, Marco; Levai, Peter; Li, Shuang; Li, Xiaomei; Lien, Jorgen Andre; Lietava, Roman; Lindal, Svein; Lindenstruth, Volker; Lippmann, Christian; Lisa, Michael Annan; Ljunggren, Hans Martin; Lodato, Davide Francesco; Lonne, Per-Ivar; Loggins, Vera Renee; Loginov, Vitaly; Loizides, Constantinos; Lokesh, Kumar; Lopez, Xavier Bernard; Lopez Torres, Ernesto; Lowe, Andrew John; Lu, Xianguo; Luettig, Philipp Johannes; Lunardon, Marcello; Luparello, Grazia; Maevskaya, Alla; Mager, Magnus; Mahajan, Sanjay; Mahmood, Sohail Musa; Maire, Antonin; Majka, Richard Daniel; Malaev, Mikhail; Maldonado Cervantes, Ivonne Alicia; Malinina, Liudmila; Mal'Kevich, Dmitry; Malzacher, Peter; Mamonov, Alexander; Manceau, Loic Henri Antoine; Manko, Vladislav; Manso, Franck; Manzari, Vito; Marchisone, Massimiliano; Mares, Jiri; Margagliotti, Giacomo Vito; Margotti, Anselmo; Margutti, Jacopo; Marin, Ana Maria; Markert, Christina; Marquard, Marco; Martin, Nicole Alice; Martin Blanco, Javier; Martinengo, Paolo; Martinez Hernandez, Mario Ivan; Martinez-Garcia, Gines; Martinez Pedreira, Miguel; Martynov, Yevgen; Mas, Alexis Jean-Michel; Masciocchi, Silvia; Masera, Massimo; Masoni, Alberto; Massacrier, Laure Marie; Mastroserio, Annalisa; Masui, Hiroshi; Matyja, Adam Tomasz; Mayer, Christoph; Mazer, Joel Anthony; Mazzoni, Alessandra Maria; Mcdonald, Daniel; Meddi, Franco; Menchaca-Rocha, Arturo Alejandro; Meninno, Elisa; Mercado-Perez, Jorge; Meres, Michal; Miake, Yasuo; Mieskolainen, Matti Mikael; Mikhaylov, Konstantin; Milano, Leonardo; Milosevic, Jovan; Minervini, Lazzaro Manlio; Mischke, Andre; Mishra, Aditya Nath; Miskowiec, Dariusz Czeslaw; Mitra, Jubin; Mitu, Ciprian Mihai; Mohammadi, Naghmeh; Mohanty, Bedangadas; Molnar, Levente; Montano Zetina, Luis Manuel; Montes Prado, Esther; Morando, Maurizio; Moreira De Godoy, Denise Aparecida; Moretto, Sandra; Morreale, Astrid; Morsch, Andreas; Muccifora, Valeria; Mudnic, Eugen; Muhlheim, Daniel Michael; Muhuri, Sanjib; Mukherjee, Maitreyee; Muller, Hans; Mulligan, James Declan; Gameiro Munhoz, Marcelo; Murray, Sean; Musa, Luciano; Musinsky, Jan; Nandi, Basanta Kumar; Nania, Rosario; Nappi, Eugenio; Naru, Muhammad Umair; Nattrass, Christine; Nayak, Kishora; Nayak, Tapan Kumar; Nazarenko, Sergey; Nedosekin, Alexander; Nellen, Lukas; Ng, Fabian; Nicassio, Maria; Niculescu, Mihai; Niedziela, Jeremi; Nielsen, Borge Svane; Nikolaev, Sergey; Nikulin, Sergey; Nikulin, Vladimir; Noferini, Francesco; Nomokonov, Petr; Nooren, Gerardus; Norman, Jaime; Nyanin, Alexander; Nystrand, Joakim Ingemar; Oeschler, Helmut Oskar; Oh, Saehanseul; Oh, Sun Kun; Ohlson, Alice Elisabeth; Okatan, Ali; Okubo, Tsubasa; Olah, Laszlo; Oleniacz, Janusz; Oliveira Da Silva, Antonio Carlos; Oliver, Michael Henry; Onderwaater, Jacobus; Oppedisano, Chiara; Ortiz Velasquez, Antonio; Oskarsson, Anders Nils Erik; Otwinowski, Jacek Tomasz; Oyama, Ken; Ozdemir, Mahmut; Pachmayer, Yvonne Chiara; Pagano, Paola; Paic, Guy; Pajares Vales, Carlos; Pal, Susanta Kumar; Pan, Jinjin; Pant, Divyash; Papikyan, Vardanush; Pappalardo, Giuseppe; Pareek, Pooja; Park, Woojin; Parmar, Sonia; Passfeld, Annika; Paticchio, Vincenzo; Paul, Biswarup; Pawlak, Tomasz Jan; Peitzmann, Thomas; Pereira Da Costa, Hugo Denis Antonio; Pereira De Oliveira Filho, Elienos; Peresunko, Dmitry Yurevich; Perez Lara, Carlos Eugenio; Peskov, Vladimir; Pestov, Yury; Petracek, Vojtech; Petrov, Viacheslav; Petrovici, Mihai; Petta, Catia; Piano, Stefano; Pikna, Miroslav; Pillot, Philippe; Pinazza, Ombretta; Pinsky, Lawrence; Piyarathna, Danthasinghe; Ploskon, Mateusz Andrzej; Planinic, Mirko; Pluta, Jan Marian; Pochybova, Sona; Podesta Lerma, Pedro Luis Manuel; Poghosyan, Martin; Polishchuk, Boris; Poljak, Nikola; Poonsawat, Wanchaloem; Pop, Amalia; Porteboeuf, Sarah Julie; Porter, R Jefferson; Pospisil, Jan; Prasad, Sidharth Kumar; Preghenella, Roberto; Prino, Francesco; 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2015-05-27
The measurement of primary $\\pi^{\\pm}$, K$^{\\pm}$, p and $\\overline{p}$ production at mid-rapidity ($|y| <$ 0.5) in proton-proton collisions at $\\sqrt{s} = 7$ TeV performed with ALICE (A Large Ion Collider Experiment) at the Large Hadron Collider (LHC) is reported. Particle identification is performed using the specific ionization energy loss and time-of-flight information, the ring-imaging Cherenkov technique and the kink-topology identification of weak decays of charged kaons. Transverse momentum spectra are measured from 0.1 up to 3 GeV/$c$ for pions, from 0.2 up to 6 GeV/$c$ for kaons and from 0.3 up to 6 GeV/$c$ for protons. The measured spectra and particle ratios are compared with QCD-inspired models, tuned to reproduce also the earlier measurements performed at the LHC. Furthermore, the integrated particle yields and ratios as well as the average transverse momenta are compared with results at lower collision energies.
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Riggi, F; Ristea, C; Rivetti, A; Rocco, E; Cahuantzi, M Rodríguez; Manso, A Rodriguez; Røed, K; Rogochaya, E; Rohr, D; Röhrich, D; Romita, R; Ronchetti, F; Ronflette, L; Rosnet, P; Rossi, A; Roukoutakis, F; Roy, A; Roy, C; Roy, P; Montero, A J Rubio; Rui, R; Russo, R; Ryabinkin, E; Ryabov, Y; Rybicki, A; Sadovsky, S; Šafařík, K; Sahlmuller, B; Sahoo, P; Sahoo, R; Sahoo, S; Sahu, P K; Saini, J; Sakai, S; Saleh, M A; Salgado, C A; Salzwedel, J; Sambyal, S; Samsonov, V; Castro, X Sanchez; Šándor, L; Sandoval, A; Sano, M; Santagati, G; Sarkar, D; Scapparone, E; Scarlassara, F; Scharenberg, R P; Schiaua, C; Schicker, R; Schmidt, C; Schmidt, H R; Schuchmann, S; Schukraft, J; Schulc, M; Schuster, T; Schutz, Y; Schwarz, K; Schweda, K; Scioli, G; Scomparin, E; Scott, R; Seeder, K S; Seger, J E; Sekiguchi, Y; Selyuzhenkov, I; Senosi, K; Seo, J; Serradilla, E; Sevcenco, A; Shabanov, A; Shabetai, A; Shadura, O; Shahoyan, R; Shangaraev, A; Sharma, A; Sharma, N; Shigaki, K; Shtejer, K; Sibiriak, Y; Siddhanta, S; Sielewicz, K M; Siemiarczuk, T; Silvermyr, D; Silvestre, C; Simatovic, G; Simonetti, G; Singaraju, R; Singh, R; Singha, S; Singhal, V; Sinha, B C; Sinha, T; Sitar, B; Sitta, M; Skaali, T B; Slupecki, M; Smirnov, N; Snellings, R J M; Snellman, T W; Søgaard, C; Soltz, R; Song, J; Song, M; Song, Z; Soramel, F; Sorensen, S; Spacek, M; Spiriti, E; Sputowska, I; Stassinaki, M Spyropoulou; Srivastava, B K; Stachel, J; Stan, I; Stefanek, G; Steinpreis, M; Stenlund, E; Steyn, G; Stiller, J H; Stocco, D; Strmen, P; Suaide, A A P; Sugitate, T; Suire, C; Suleymanov, M; Sultanov, R; Šumbera, M; Symons, T J M; Szabo, A; Toledo, A Szanto de; Szarka, I; Szczepankiewicz, A; Szymanski, M; Takahashi, J; Tanaka, N; Tangaro, M A; Takaki, J D Tapia; Peloni, A Tarantola; Tariq, M; Tarzila, M G; Tauro, A; Muñoz, G Tejeda; Telesca, A; Terasaki, K; Terrevoli, C; Teyssier, B; Thäder, J; Thomas, D; Tieulent, R; Timmins, A R; Toia, A; Trogolo, S; Trubnikov, V; Trzaska, W H; Tsuji, T; Tumkin, A; Turrisi, R; Tveter, T S; Ullaland, K; Uras, A; Usai, G L; Utrobicic, A; Vajzer, M; Vala, M; Palomo, L Valencia; Vallero, S; Maarel, J Van Der; Hoorne, J W Van; Leeuwen, M van; Vanat, T; Vyvre, P Vande; Varga, D; Vargas, A; Vargyas, M; Varma, R; Vasileiou, M; Vasiliev, A; Vauthier, A; Vechernin, V; Veen, A M; Veldhoen, M; Velure, A; Venaruzzo, M; Vercellin, E; Limón, S Vergara; Vernet, R; Verweij, M; Vickovic, L; Viesti, G; Viinikainen, J; Vilakazi, Z; Baillie, O Villalobos; Vinogradov, A; Vinogradov, L; Vinogradov, Y; Virgili, T; Vislavicius, V; Viyogi, Y P; Vodopyanov, A; Völkl, M A; Voloshin, K; Voloshin, S A; Volpe, G; Haller, B von; Vorobyev, I; Vranic, D; Vrláková, J; Vulpescu, B; Vyushin, A; Wagner, B; Wagner, J; Wang, H; Wang, M; Wang, Y; Watanabe, D; Weber, M; Weber, S G; Wessels, J P; Westerhoff, U; Wiechula, J; Wikne, J; Wilde, M; Wilk, G; Wilkinson, J; Williams, M C S; Windelband, B; Winn, M; Yaldo, C G; Yamaguchi, Y; Yang, H; Yang, P; Yano, S; Yasnopolskiy, S; Yin, Z; Yokoyama, H; Yoo, I-K; Yurchenko, V; Yushmanov, I; Zaborowska, A; Zaccolo, V; Zaman, A; Zampolli, C; Zanoli, H J C; Zaporozhets, S; Zarochentsev, A; Závada, P; Zaviyalov, N; Zbroszczyk, H; Zgura, I S; Zhalov, M; Zhang, H; Zhang, X; Zhang, Y; Zhao, C; Zhigareva, N; Zhou, D; Zhou, Y; Zhou, Z; Zhu, H; Zhu, J; Zhu, X; Zichichi, A; Zimmermann, A; Zimmermann, M B; Zinovjev, G; Zyzak, M
The measurement of primary [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] production at mid-rapidity ([Formula: see text] 0.5) in proton-proton collisions at [Formula: see text][Formula: see text] 7 TeV performed with a large ion collider experiment at the large hadron collider (LHC) is reported. Particle identification is performed using the specific ionisation energy-loss and time-of-flight information, the ring-imaging Cherenkov technique and the kink-topology identification of weak decays of charged kaons. Transverse momentum spectra are measured from 0.1 up to 3 GeV/[Formula: see text] for pions, from 0.2 up to 6 GeV/[Formula: see text] for kaons and from 0.3 up to 6 GeV/[Formula: see text] for protons. The measured spectra and particle ratios are compared with quantum chromodynamics-inspired models, tuned to reproduce also the earlier measurements performed at the LHC. Furthermore, the integrated particle yields and ratios as well as the average transverse momenta are compared with results at lower collision energies.
Radiobiological work using a negative pion beam at the Rutherford Laboratory 1971-76
International Nuclear Information System (INIS)
Ellis, R.E.; Lindop, P.J.; Coggle, J.E.; Fraser, G.
1976-08-01
The subject is discussed in two sections: physics experiments (including, inter alia, dose measurement, LET distribution, radiation products of spallation); radiobiological studies (including separate reports as follows: review of experimental programme; some in vivo effects of negative pions in mice; survival and recovery of Hela cells in vitro; negative pion dose-response curves for frozen Hela cells; response of vicia faba to irradiation with negative pions; pion experiments with chromosome aberrations). (U.K.)
Threshold pion production in NN→dπ and γN→Nπ
International Nuclear Information System (INIS)
Korkmaz, E.
1993-01-01
Specific threshold pion production studies are discussed. The NN→dπ results provide a concise description of the pion production amplitudes at threshold. The charged-pion γN→Nπ measurement should complement recent (and upcoming) neutral-pion experiments, providing a test of our understanding of the role of chiral symmetry in the strong interaction. (author) 5 tabs., 17 figs., 22 refs
Pion-nucleon vertex function and the Chew-Low model
International Nuclear Information System (INIS)
Nutt, W.T.
1977-01-01
We provide an interpretation of the cutoff function used in the Chew-Low theory of pion-nucleon scattering. It is shown that this function may be related to the pion-pion interaction which is not explicitly considered in the Chew-Low approach. Using a previously developed model for the pion-nucleon vertex function, we then perform a ''parameter-free'' Chew-Low calculation which predicts the P 33 resonance quite well
Measurement of the charged pion polarizability at COMPASS
International Nuclear Information System (INIS)
Nagel, Thiemo Christian Ingo
2012-01-01
The reaction π - +Z→π - +γ+Z in which a photon is produced by a beam pion scattering off a quasi-real photon of the Coulomb field of the target nucleus is identified experimentally by the tiny magnitude of the momentum transfer to the nucleus. This process gives access to the charged pion polarizabilities α π and β π whose experimental determination constitutes an important test of Chiral Perturbation Theory. In this work, the pion polarizability is obtained as α π =(1.9±0.7 stat. ±0.8 syst. ) x 10 -4 fm 3 from data taken with 190 GeV/c hadron beam provided by SPS to the COMPASS experiment at CERN in November 2009 and under the assumption of α π +β π =0.
Pions as collective modes in the glueball condensate vacuum
Energy Technology Data Exchange (ETDEWEB)
Hansson, T.H.; Zahed, I.
1987-07-01
The glueball condensate vacuum model is extended to incorporate the effects of light quarks. The resulting model exhibits spontaneous breaking of chiral SU(2)/sub f/ symmetry, and has a new kind of collective excitations, pions, which are distinct from the usual bag-model-type states. The dynamics of the pions are described by a sigma model, and the parameters
Measurement of the charged pion polarizability at COMPASS
Energy Technology Data Exchange (ETDEWEB)
Nagel, Thiemo Christian Ingo
2012-09-26
The reaction {pi}{sup -}+Z{yields}{pi}{sup -}+{gamma}+Z in which a photon is produced by a beam pion scattering off a quasi-real photon of the Coulomb field of the target nucleus is identified experimentally by the tiny magnitude of the momentum transfer to the nucleus. This process gives access to the charged pion polarizabilities {alpha}{sub {pi}} and {beta}{sub {pi}} whose experimental determination constitutes an important test of Chiral Perturbation Theory. In this work, the pion polarizability is obtained as {alpha}{sub {pi}}=(1.9{+-}0.7{sub stat.}{+-}0.8{sub syst.}) x 10{sup -4} fm{sup 3} from data taken with 190 GeV/c hadron beam provided by SPS to the COMPASS experiment at CERN in November 2009 and under the assumption of {alpha}{sub {pi}}+{beta}{sub {pi}}=0.
Pion-Skyrmion scattering: collective coordinates at work
International Nuclear Information System (INIS)
Peskin, M.E.
1985-06-01
It is argued that the Skryme model, and more generally, the picture of the nucleon as a chiral soliton, can give a qualitatively correct picture of pion-nucleon scattering, considering both group-theoretic and more scheme-dependent results. The properties of the nucleon and its excited states in large-N quantum chromodynamics are discussed qualitatively. Then the pion-nucleon S-matrix is reduced. It is found that the model succeeds at the first level of calculation in producing many of the features of pion-nucleon scattering which are revealed by experiment, but that many aspects of the description need to be better understood, including the treatment of nonleading corrections near threshold and the inclusion of inelastic channels. 22 refs., 8 figs
Pion production in relativistic collisions of nuclear drops
International Nuclear Information System (INIS)
Alonso, C.T.; Wilson, J.R.; McAbee, T.L.; Zingman, J.A.
1988-09-01
In a continuation of the long-standing effort of the nuclear physics community to model atomic nuclei as droplets of a specialized nuclear fluid, we have developed a hydrodynamic model for simulating the collisions of heavy nuclei at relativistic speeds. Our model couples ideal relativistic hydrodynamics with a new Monte Carlo treatment of dynamic pion production and tracking. The collective flow for low-energy (200 MeV/N) collisions predicted by this model compares favorably with results from earlier hydrodynamic calculations which used quite different numerical techniques. Our pion predictions at these lower energies appear to differ, however, from the experimental data on pion multiplicities. In this case of ultra-relativistic (200 GeV/N) collisions, our hydrodynamic model has produced baryonic matter distributions which are in reasonable agreement with recent experimental data. These results may shed some light on the sensitivity of relativistic collision data to the nuclear equation of state. 20 refs., 12 figs
QCD-based pion distribution amplitudes confronting experimental data
International Nuclear Information System (INIS)
Bakulev, A.P.; Mikhajlov, S.V.; Stefanis, N.G.
2001-01-01
We use QCD sum rules with nonlocal condensates to recalculate more accurately the moments and their confidence intervals of the twist-2 pion distribution amplitude including radiative corrections. We are thus able to construct an admissible set of pion distribution amplitudes which define a reliability region in the a 2 , a 4 plane of the Gegenbauer polynomial expansion coefficients. We emphasize that models like that of Chernyak and Zhitnitsky, as well as the asymptotic solution, are excluded from this set. We show that the determined a 2 , a 4 region strongly overlaps with that extracted from the CLEO data by Schmedding and Yakovlev and that this region is also not far from the results of the first direct measurement of the pion valence quark momentum distribution by the Fermilab E791 collaboration. Comparisons with recent lattice calculations and instanton-based models are briefly discussed
Low-energy photo- and electroproduction for physical pions
International Nuclear Information System (INIS)
MacMullen, J.T.
1979-02-01
The background resonance Δ(1230), Nsup(*)(1520), Nsup(*)(1470) and Nsup(*)(1535)pion and axial-vector amplitudes are first calculated in the soft pion and on-shell configuration, respectively. Then a comparison is made with the usual soft pion theorems and on-shell low-energy expansions of current algebra as worked out in the previous paper. The agreement is good and we also deduce a nucleon dipole form factor axial-vector mass of msub(A)approximately equal to 1,23 GeV. Finally an approximate value for the non-strange current quark mass of m equal to 0,64 +- 1,11μ is extracted from the data
Reggeon and pion contributions in exclusive diffractive processes at HERA
International Nuclear Information System (INIS)
Golec-Biernat, K.; Kwiecinski, J.; Szczurek, A.
1997-01-01
The contribution of subleading f 2 , ω, a 2 and ρ reggeons to the diffractive structure function F 2 D(3) (x P , β, Q 2 )are estimated. In addition we include the pion exchange which was recently found to be responsible for the violation of the Gottfried Sum Rule. The reggeon and pion contribution lead to a violation of the factorization of the diffractive structure function. The diffractive structure function is separated into the contributions with leading proton Δ (n) F 2 D /Δ (p) F 2 D as a function ox x P in the interval 10 -2 P -1 . The effect is due to the exchange of the isovector a 2 and ρ reggeons at smaller x P and the pion exchange at x P > 10 -2 . (author). 27 refs, 4 figs
On pion-nucleus scattering, paper-I
International Nuclear Information System (INIS)
Begum, L.; Nahar, W.; Haque, Sangita; Rahman, S. Nasmin; Rahman, Md.A.
2003-06-01
The strong absorption model of Frahn and Venter is used to study the elastic scattering of pions at energies below and above the Delta resonance from a number of nuclei between 14 N and 152 Sm. A reasonable good fit is obtained in each case over the entire angular range except for a few cases of 65 and 80 MeV data where clearly the strong absorption conditions are not perfectly satisfied. The best fit parameters values of the model and their systematics are discussed. The inelastic scattering of pions is then studied. Pions leading to the lowest 2 + and 3 - collective states in some nuclei are analyzed. Again a good account of the inelastic scattering processes is possible without any readjustment of any elastic scattering parameters. The relevant deformation parameters are extracted. The proton and neutron matrix elements M p and M n are extracted from the proton and neutron deformation parameters β p and β n respectively. (author)
Relativistic generalizations of simple pion-nucleon models
International Nuclear Information System (INIS)
McLeod, R.J.; Ernst, D.J.
1981-01-01
A relativistic, partial wave N/D dispersion theory is developed for low energy pion-nucleon elastic scattering. The theory is simplified by treating crossing symmetry only to lowest order in the inverse nucleon mass. The coupling of elastic scattering to inelastic channels is included by taking the necessary inelasticity from experimental data. Three models are examined: pseudoscalar coupling of pions and nucleons, pseudovector coupling, and a model in which all intermediate antinucleons are projected out of the amplitude. The phase shifts in the dominant P 33 channel are quantitatively reproduced for P/sub lab/ 33 phase shifts. Thus a model of the pion-nucleon interaction which does not include antinucleon degrees of freedom is found to be unphysical
Elastic and charge-exchange scattering of pions from 3He and 3H
International Nuclear Information System (INIS)
Gibson, B.F.; Hess, A.T.
1976-04-01
We have examined (1) the elastic scattering of pions from the isodoublet 3 He and 3 H and (2) the single charge-exchange reaction 3 H(π + ,π 0 ) 3 He using a formalism which incorporates the π-N multiple scattering to all orders. Emphasis is placed on numerical results which illustrate those features of the differential cross sections that are expected to be of interest to the experimentalist. Realistic nuclear densities corresponding to the form factors of elastic electron scattering were used. Charge-exchange cross sections are presented in terms of angular distributions for both the π 0 and the recoil nucleus. In elastic scattering, Coulomb-nuclear interference effects are significant at incident pion kinetic energies of less than 100 MeV; form factor effects are apparent at large momentum transfer. Comparison of data and theory for π + - 3 He with that for π - - 3 He (or the conjugate π + - 3 H) will provide a test of the convergence of the fixed scatterer, multiple-scattering formalism utilized in this report. 21 figures
Measurement of the production of charged pions by protons on a tantalum target
Catanesi, M.G.; Edgecock, R.; Ellis, Malcolm; Robbins, S.; Soler, F.J.P.; Gossling, C.; Bunyatov, S.; Krasnoperov, A.; Popov, B.; Serdiouk, V.; Tereschenko, V.; Di Capua, E.; Vidal-Sitjed, G.; Artamonov, A.; Arce, P.; Giani, S.; Gilardoni, S.; Gorbunov, P.; Grant, A.; Grossheim, A.; Gruber, P.; Ivanchenko, V.; Kayis-Topaksu, A.; Panman, J.; Papadopoulos, I.; Pasternak, J.; Tcherniaev, E.; Tsukerman, I.; Veenhof, R.; Wiebusch, C.; Zucchelli, P.; Blondel, A.; Borghi, S.; Campanelli, M.; Morone, M.C.; Prior, G.; Schroeter, R.; Engel, R.; Meurer, C.; Kato, I.; Gastaldi, U.; Mills, G.B.; Graulich, J.S.; Gregoire, G.; Bonesini, M.; De Min, A.; Ferri, F.; Paganoni, M.; Paleari, F.; Kirsanov, M.; Bagulya, A.; Grichine, V.; Polukhina, N.; Palladino, V.; Coney, L.; Schmitz, D.; Barr, G.; De Santo, A.; Pattison, C.; Zuber, K.; Bobisut, F.; Gibin, D.; Guglielmi, A.; Mezzetto, M.; Dumarchez, J.; Vannucci, F.; Dore, U.; Orestano, D.; Pastore, F.; Tonazzo, A.; Tortora, L.; Booth, C.; Buttar, C.; Hodgson, P.; Howlett, L.; Bogomilov, M.; Chizhov, M.; Kolev, D.; Tsenov, R.; Apollonio, M.; Chimenti, P.; Giannini, G.; Santin, G.; Burguet-Castell, J.; Cervera-Villanueva, A.; Gomez-Cadenas, J.J.; Martin-Albo, J.; Novella, P.; Sorel, M.; Tornero, A.
2007-01-01
A measurement of the double-differential cross-section for the production of charged pions in proton--tantalum collisions emitted at large angles from the incoming beam direction is presented. The data were taken in 2002 with the HARP detector in the T9 beam line of the CERN PS. The pions were produced by proton beams in a momentum range from 3 \\GeVc to 12 \\GeVc hitting a tantalum target with a thickness of 5% of a nuclear interaction length. The angular and momentum range covered by the experiment ($100 \\MeVc \\le p < 800 \\MeVc$ and $0.35 \\rad \\le \\theta <2.15 \\rad$) is of particular importance for the design of a neutrino factory. The produced particles were detected using a small-radius cylindrical time projection chamber (TPC) placed in a solenoidal magnet. Track recognition, momentum determination and particle identification were all performed based on the measurements made with the TPC. An elaborate system of detectors in the beam line ensured the identification of the incident particles. Results a...
PIGMI: a design report for Pion Generator for Medical Irradiations
International Nuclear Information System (INIS)
Hansborough, L.D.
1981-09-01
PIGMI (Pion Generator for Medical Irradiations) is an integrated linear accelerator (linac) system developed under the auspices of the National Cancer Institute for specific application to cancer treatment in a hospital environment. In its full configuration, PIGMI is a proton linac that is far smaller, less expensive, and more reliable than previous machines that produce pions. Subsets of PIGMI technology can be used with equal advantage to generate beams of other particles (such as neutrons, protons, or heavy ions) that may be of interest for radiotherapy, radioisotope production, or other applications. The dramatic performance and cost advantages of this new breed of acceleraor result from a number of improvements. In the low-energy portion of the machine, a new type of low-energy linac (the radio-frequency quadrupole[RFQ]) produces an exceptionally good quality beam, and uses a very simple 30-kV injector. In the second part of the machine (the drift-tube linac [DTL]), high accelerating gradients are now achievable with consequent reductions in machine length. Another new structure (the disk and washer [DAW]) will be used in the third and final section of the accelerator; this portion will also be relatively short and require few power amplifiers. The entire machine is designed for ease of operation and high reliability. The pion-production machine, discussed in this report, accelerates a 100-μA average proton-beam current to 650 MeV; use of an efficient pion-collection channel would result in an average pion flux of over 100 rad/min in a volume of about 1 l. Pion-channel design is not treated in this report. Accelerator construction cost is estimated at $10 million (1980 dollars); site preparation and treatment facility costs would bring the cost of a complete facility to an estimated $25 million
Multiplicity fluctuations of pions and protons at SPS energy–An in ...
Indian Academy of Sciences (India)
We compute the factorial correlators to study the dynamical fluctuations of pions and a combination of pions and protons (compound multiplicity) in 32S–AgBr interactions at 200 A GeV. The study reveals that for both pion and compound multiplicity the correlated moments increase with the decrease in bin–bin separation , ...
Measurement of Antiproton-proton Cross-Sections at Low Antiproton Momenta
2002-01-01
The experiment is designed to measure four different cross sections in the momentum range 150~MeV/c to 600~MeV/c: 1)~~~~the differential elastic \\\\ \\\\ 2)~~~~the differential charge exchange\\\\ \\\\ 3)~~~~the annihilation into charged and neutral pions\\\\ \\\\ 4)~~~~and the total cross section via the optical theorem. \\\\ \\\\ The experiment allows one to search once again and with good precision for baryonium. Of special interest is the existence of the S-meson, for which a signal of about 20~MeV-mb was found in a 1981 experiment (performed in the East Hall).\\\\ \\\\ A second point of special interest is the momentum region below 300~MeV/c because the cross sections are basically unknown. We will be able to explore the momentum dependence of this region for the first time.\\\\ \\\\ The elastic cross section is measured by a cylindrical multiwire proportional chamber and a scintillator hodoscope placed around a scattering chamber under vacuum. The charge exchange cross section is measured by a ring of 32~anti-neutron detector...
Energy Technology Data Exchange (ETDEWEB)
Peters, Andreas
2008-02-15
We consider pion electroproduction close to threshold for Q{sup 2} in the region 1-10 GeV{sup 2} on a nucleon target. The momentum transfer dependence of the S-wave multipoles at threshold, E{sub 0+} and L{sub 0+}, is calculated in the chiral limit using light-cone sum rules. Predictions for the cross sections in the threshold region are given taking into account P-wave contributions that, as we argue, are model independent to a large extent. The results are compared with the SLAC E136 data on the structure function F{sub 2}(W,Q{sup 2}) in the threshold region. (orig.)
Scaling study of the pion electroproduction cross sections and the pion form factor
International Nuclear Information System (INIS)
Tanja Horn; Xin Qian; John Arrington; Razmik Asaturyan; Fatiha Benmokthar; Werner Boeglin; Peter Bosted; Antje Bruell; Eric Christy; Eugene Chudakov; Ben Clasie; Mark Dalton; AJI Daniel; Donal Day; Dipangkar Dutta; Lamiaa El Fassi; Rolf Ent; Howard Fenker; J. Ferrer; Nadia Fomin; H. Gao; K Garrow; Dave Gaskell; C Gray; G. Huber; M. Jones; N Kalantarians; C. Keppel; K Kramer; Y Li; Y Liang; A. Lung; S Malace; P. Markowitz; A. Matsumura; D. Meekins; T Mertens; T Miyoshi; H. Mykrtchyan; R. Monson; T. Navasardyan; G. Niculescu; I. Niculescu; Y. Okayasu; A. Opper; C Perdrisat; V. Punjabi; A. Rauf; V. Rodriguez; D. Rohe; J Seely; E Segbefia; G. Smith; M. Sumihama; V. Tadevoyan; L Tang; V. Tvaskis; A. Villano; W. Vulcan; F. Wesselmann; S. Wood; L. Yuan; X. Zheng
2007-01-01
The 1 H(e,e(prime)π + )n cross section was measured for a range of four-momentum transfer up to Q 2 =3.91 GeV 2 at values of the invariant mass, W, above the resonance region. The Q 2 -dependence of the longitudinal component is consistent with the Q 2 -scaling prediction for hard exclusive processes. This suggests that perturbative QCD concepts are applicable at rather low values of Q 2 . Pion form factor results, while consistent with the Q 2 -scaling prediction, are inconsistent in magnitude with perturbative QCD calculations. The extraction of Generalized Parton Distributions from hard exclusive processes assumes the dominance of the longitudinal term. However, transverse contributions to the cross section are still significant at Q 2 =3.91 GeV 2
Nonpartonic Effects in Pion Electroproduction in the Hermes Kinematical Region
International Nuclear Information System (INIS)
Uleshchenko, V.; Szczurek, A.
2002-01-01
The presentation is concerned with higher twist corrections of nonpartonic origin to semi-inclusive observables in the kinematical region relevant for the HERMES experiment. We demonstrate a strong impact of the VDM-like interaction and the exclusive production of ρ 0 meson on the extraction of the (anti)d - (anti)u asymmetry from charged pion DIS multiplicities. We also show that it is the exclusive- ρ 0 channel which accounts for the experimentally observed effect of the excess of charged over neutral pions produced at large z. (author)
Neutral pion form factor measurement by the NA62 experiment
Zamkovsky, Michal; Ambrosino, F.; Antonelli, A.; Anzivino, G.; Arcidiacono, R.; Baldini, W.; Balev, S.; Batley, J. R.; Behler, M.; Bifani, S.; Biino, C.; Bizzeti, A.; Blazek, T.; Bloch-Devaux, B.; Bocquet, G.; Bolotov, V.; Bucci, F.; Cabibbo, N.; Calvetti, M.; Cartiglia, N.; Ceccucci, A.; Cenci, P.; Cerri, C.; Cheshkov, C.; Chze, J. B.; Clemencic, M.; Collazuol, G.; Costantini, F.; Cotta Ramusino, A.; Coward, D.; Cundy, D.; Dabrowski, A.; DAgostini, G.; Dalpiaz, P.; Damiani, C.; Danielsson, H.; De Beer, M.; Dellacasa, G.; Derr, J.; Dibon, H.; Di Filippo, D.; DiLella, L.; Doble, N.; Duk, V.; Engelfried, J.; Eppard, K.; Falaleev, V.; Fantechi, R.; Fidecaro, M.; Fiorini, L.; Fiorini, M.; Fonseca Martin, T.; Frabetti, P. L.; Fucci, A.; Gallorini, S.; Gatignon, L.; Gersabeck, E.; Gianoli, A.; Giudici, S.; Gonidec, A.; Goudzovski, E.; Goy Lopez, S.; Gushchin, E.; Hallgren, B.; Hita-Hochgesand, M.; Holder, M.; Hristov, P.; Iacopini, E.; Imbergamo, E.; Jeitler, M.; Kalmus, G.; Kekelidze, V.; Kleinknecht, K.; Koval, M.; Kozhuharov, V.; Kubischta, W.; Kurshetsov, V.; Lamanna, G.; Lazzeroni, C.; Lenti, M.; Leonardi, E.; Litov, L.; Lurkin, N.; Madigozhin, D.; Maier, A.; Mannelli, I.; Marchetto, F.; Marel, G.; Markytan, M.; Marouelli, P.; Martini, M.; Masetti, L.; Massarotti, P.; Mazzucato, E.; Michetti, A.; Mikulec, I.; Misheva, M.; Molokanova, N.; Monnier, E.; Moosbrugger, U.; Morales Morales, C.; Moulson, M.; Movchan, S.; Munday, D. J.; Napolitano, M.; Nappi, A.; Neuhofer, G.; Norton, A.; Numao, T.; Obraztsov, V.; Palladino, V.; Patel, M.; Pepe, M.; Peters, A.; Petrucci, F.; Petrucci, M. C.; Peyaud, B.; Piandani, R.; Piccini, M.; Pierazzini, G.; Polenkevich, I.; Popov, I.; Potrebenikov, Y.; Raggi, M.; Renk, B.; Retire, F.; Riedler, P.; Romano, A.; Rubin, P.; Ruggiero, G.; Salamon, A.; Saracino, G.; Savri, M.; Scarpa, M.; Semenov, V.; Sergi, A.; Serra, M.; Shieh, M.; Shkarovskiy, S.; Slater, M. W.; Sozzi, M.; Spadaro, T.; Stoynev, S.; Swallow, E.; Szleper, M.; Valdata-Nappi, M.; Valente, P.; Vallage, B.; Velasco, M.; Veltri, M.; Venditti, S.; Wache, M.; Wahl, H.; Walker, A.; Wanke, R.; Widhalm, L.; Winhart, A.; Winston, R.; Wood, M. D.; Wotton, S. A.; Yushchenko, O.; Zinchenko, A.; Ziolkowski, M.
2017-07-01
The NA62 experiment at CERN collected a large sample of charged kaon decays with a highly efficient trigger for decays into electrons in 2007. The kaon beam represents a source of tagged neutral pion decays in vacuum. A measurement of the electromagnetic transition form factor slope of the neutral pion in the time-like region from ∼1 million fully reconstructed π 0 Dalitz decay is presented. The limits on dark photon production in π 0 decays from the earlier kaon experiment at CERN, NA48/2, are also reported.
Pion production in nucleon-nucleon collisions at low energies
Energy Technology Data Exchange (ETDEWEB)
Baru, Vadim [Institut fuer Kernphysik (Theorie), Juelich Center for Hadron Physics, Forschungszentrum Juelich, D-52425 Juelich (Germany); Institute for Theoretical and Experimental Physics, 117218, B. Cheremushkinskaya 25, Moscow (Russian Federation); Epelbaum, Evgeny [Institut fuer Kernphysik (Theorie), Juelich Center for Hadron Physics, Forschungszentrum Juelich, D-52425 Juelich (Germany); Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie), Universitaet Bonn, D-53115 Bonn (Germany); Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany); Filin, Arseniy [Institute for Theoretical and Experimental Physics, 117218, B. Cheremushkinskaya 25, Moscow (Russian Federation); Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie), Universitaet Bonn, D-53115 Bonn (Germany); Haidenbauer, Johann; Hanhart, Christoph [Institut fuer Kernphysik (Theorie), Juelich Center for Hadron Physics, Forschungszentrum Juelich, D-52425 Juelich (Germany); Institute for Advanced Simulation, Forschungszentrum Juelich, D-52425 Juelich (Germany); Kudryavtsev, Alexander [Institute for Theoretical and Experimental Physics, 117218, B. Cheremushkinskaya 25, Moscow (Russian Federation); Lensky, Vadim [Institute for Theoretical and Experimental Physics, 117218, B. Cheremushkinskaya 25, Moscow (Russian Federation); European Centre for Theoretical Studies in Nuclear Physics and Related Areas, Villazzano (Trento) (Italy); Meissner, Ulf G. [Institut fuer Kernphysik (Theorie), Juelich Center for Hadron Physics, Forschungszentrum Juelich, D-52425 Juelich (Germany); Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie), Universitaet Bonn, D-53115 Bonn (Germany); Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany); Institute for Advanced Simulation, Forschungszentrum Juelich, D-52425 Juelich (Germany)
2010-07-01
With the advent of chiral perturbation theory, the low-energy effective field theory of QCD, high accuracy calculations for hadronic reactions with a controlled error estimation have become possible. We survey the recent developments in the reaction NN{yields}NN{pi} in chiral EFT. We argue that the counting scheme that acknowledges the large momentum transfer between the initial and the final nucleons allows for a consistent description of s- and p-wave pion production. The status of the theory for pion production in the isospin conserving case allows us to challenge charge symmetry breaking effects recently observed experimentally in pn{yields}d{pi}{sup 0}.
Towards a dispersive determination of the pion transition form factor
Leupold Stefan; Hoferichter Martin; Kubis Bastian; Niecknig Franz; Schneider Sebastian P.
2018-01-01
We start with a brief motivation why the pion transition form factor is interesting and, in particular, how it is related to the high-precision standard-model calculation of the gyromagnetic ratio of the muon. Then we report on the current status of our ongoing project to calculate the pion transition form factor using dispersion theory. Finally we present and discuss a wish list of experimental data that would help to improve the input for our calculations and/or to cross-check our results.
Exclusive measurements of neutral pion production at intermediate energies
Energy Technology Data Exchange (ETDEWEB)
Badala, A.; Barbera, R.; Palmeri, A.; Pappalardo, G.S.; Riggi, F.; Russo, A.C.; Turriso, R. [Istituto Nazionale di Fisica Nucleare, Catania (Italy); Riggi, F.; Russo, G.; Turriso, R.; Bellia, G.; Migneco, E. [Catania Univ. (Italy). Ist. di Fisica; Agodi, C.; Alba, R.; Bellia, G.; Coniglione, R.; Del Zoppo, A.; FInocchiaro, P.; Maiolino, C.; Migneco, E.; Piattelli, P.; Sapienza, P. [Istituto Nazionale di Fisica Nucleare, Catania (Italy); Peghaire, A. [Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France)
1995-12-31
Neutral pion production has been studied in the {sup 36}Ar + {sup 27}Al reaction at 94 MeV/ nucleon with the aim to get a quantitative estimate of the impact parameter involved in the process. A near 4{pi} multidetector has been used to detect both gamma rays originating from the {pi}deg decay and associated charged particles. The charged particle multiplicity has been used in the present analysis as a global variable to extract the impact parameter scale. A comparison with Boltzmann-Nordheim-Vlasov (BNV) calculations, which take into account the effect of the pion reabsorption in the nuclear matter, has been performed. (author) 23 refs.
Exclusive measurements of neutral pion production at intermediate energies
International Nuclear Information System (INIS)
Badala, A.; Barbera, R.; Palmeri, A.; Pappalardo, G.S.; Riggi, F.; Russo, A.C.; Turriso, R.; Riggi, F.; Russo, G.; Turriso, R.; Bellia, G.; Migneco, E.; Peghaire, A.
1995-01-01
Neutral pion production has been studied in the 36 Ar + 27 Al reaction at 94 MeV/ nucleon with the aim to get a quantitative estimate of the impact parameter involved in the process. A near 4π multidetector has been used to detect both gamma rays originating from the πdeg decay and associated charged particles. The charged particle multiplicity has been used in the present analysis as a global variable to extract the impact parameter scale. A comparison with Boltzmann-Nordheim-Vlasov (BNV) calculations, which take into account the effect of the pion reabsorption in the nuclear matter, has been performed. (author)
Capture and transfer of stopped pions in alcohols
International Nuclear Information System (INIS)
Harston, M.R.; Armstrong, D.S.; Measday, D.F.; Stanislaus, S.; Weber, P.; Horvath, D.
1990-02-01
The pion charge exchange probability in hydrogen for stopped π - has been measured for a series of alcohols. The relative atomic capture probabilities for hydrogen in different chemical environments as well as for the other molecular constituents were extracted from the data using a phenomenological approach. The results allow the prediction of the charge exchange probability in other molecules of similar chemical structure. The charge exchange probability in deuterated methanols was measured and compared to the prediction of our model. A comprehensive picture is obtained if pion transfer from hydrogen to deuterium is included
Evidence for delta-hole components from pion reactions
International Nuclear Information System (INIS)
Morris, C.L.
1982-01-01
Some anomalies observed in pion-induced reactions have been qualitatively explained with a model which includes Δ 3 3 admixtures in low lying nuclear states. Semi-quantitative analysis of these effects indicates the amplitudes for the Δ 3 3 admixtures necessary to explain these effects are on the order of a few percent. Although a more rigorous theoretical treatment of this problem is necessary, it appears that pion-induced reactions may provide a tool with which the spectroscopy of these Δ 3 3 -admixtures can be studied
Generalized parton distributions for the pion in chiral perturbation theory
Energy Technology Data Exchange (ETDEWEB)
Diehl, M.; Manashov, A. [Regensburg Univ. (Germany). Inst. fuer Physik 1 - Theoretische Physik]|[Sankt-Peterburgskij Univ., St. Petersburg (Russian Federation). Kafedra Teoreticheskoj Fiziki; Schaefer, A. [Regensburg Univ. (Germany). Inst. fuer Physik 1 - Theoretische Physik
2005-05-01
Generalized parton distributions provide a unified parameterization of hadron structure and allow one to combine information from many different observables. Lattice QCD calculations already provide important input to determine these distributions and hold the promise to become even more important in the future. To this end, a reliable extrapolation of lattice calculations to the physical quark and pion masses is needed. We present an analysis for the moments of generalized parton distributions of the pion in one-loop order of chiral perturbation theory. (orig.)
Generalized parton distributions for the pion in chiral perturbation theory
Energy Technology Data Exchange (ETDEWEB)
Diehl, M. [Deutsches Elektronen-Synchroton DESY, D-22603 Hamburg (Germany); Manashov, A. [Institut fuer Theoretische Physik, Universitaet Regensburg, D-93040 Regensburg (Germany) and Department of Theoretical Physics, Sankt-Petersburg State University, St. Petersburg (Russian Federation)]. E-mail: alexander.manashov@physik.uni-regensburg.de; Schaefer, A. [Institut fuer Theoretische Physik, Universitaet Regensburg, D-93040 Regensburg (Germany)
2005-08-25
Generalized parton distributions provide a unified parameterization of hadron structure and allow one to combine information from many different observables. Lattice QCD calculations already provide important input to determine these distributions and hold the promise to become even more important in the future. To this end, a reliable extrapolation of lattice calculations to the physical quark and pion masses is needed. We present an analysis for the moments of generalized parton distributions of the pion in one-loop order of chiral perturbation theory.
Towards a dispersive determination of the pion transition form factor
Directory of Open Access Journals (Sweden)
Leupold Stefan
2018-01-01
Full Text Available We start with a brief motivation why the pion transition form factor is interesting and, in particular, how it is related to the high-precision standard-model calculation of the gyromagnetic ratio of the muon. Then we report on the current status of our ongoing project to calculate the pion transition form factor using dispersion theory. Finally we present and discuss a wish list of experimental data that would help to improve the input for our calculations and/or to cross-check our results.
Measurement of the Charged Pion Electromagnetic Form Factor
International Nuclear Information System (INIS)
J. Volmer; David Abbott; H. Anklin; Chris Armstrong; John Arrington; K. Assamagan; Steven Avery; Oliver K. Baker; Henk Blok; C. Bochna; Ed Brash; Herbert Breuer; Nicholas Chant; Jim Dunne; Tom Eden; Rolf Ent; David Gaskell; Ron Gilman; Kenneth Gustafsson; Wendy Hinton; Garth Huber; Hal Jackson; Mark K. Jones; Cynthia Keppel; P.H. Kim; Wooyoung Kim; Andi Klein; Doug Koltenuk; Meme Liang; George Lolos; Allison Lung; David Mack; D. McKee; David Meekins; Joseph Mitchell; H. Mkrtchian; B. Mueller; Gabriel Niculescu; Ioana Niculescu; D. Pitz; D. Potterveld; Liming Qin; Juerg Reinhold; I.K. Shin; Stepan Stepanyan; V. Tadevosian; L.G. Tang; R.L.J. van der Meer; K. Vansyoc; D. Van Westrum; Bill Vulcan; Stephen Wood; Chen Yan; W.X. Zhao; Beni Zihlmann
2001-01-01
Separated longitudinal and transverse structure functions for the reaction 1H(e,eprime pi+)n were measured in the momentum transfer region Q2=0.6-1.6 (GeV/c)**2 at a value of the invariant mass W=1.95 GeV. New values for the pion charge form factor were extracted from the longitudinal cross section by using a recently developed Regge model. The results indicate that the pion form factor in this region is larger than previously assumed and is consistent with a monopole parameterization fitted to very low Q2 elastic data
Partonic transverse momenta in non-relativistic hyper-central quark potential models
International Nuclear Information System (INIS)
Diakonos, F.K.; Kaplis, N.K.; Maintas, X.N.
2009-01-01
We investigate the impact of three-body forces on the transverse-momentum distribution of partons inside the proton. This is achieved by considering the three-body problem in a class of hyper-central quark potential models. Solving the corresponding Schroedinger equation, we determine the quark wave function in the proton and with appropriate transformations and projections we find the transverse-momentum distribution of a single quark. In each case the parameters of the quark potentials are adjusted in order to sufficiently describe observable properties of the proton. Using a factorization ansatz, we incorporate the obtained transverse-momentum distribution in a perturbative QCD scheme for the calculation of the cross-section for prompt photon production in pp collisions. A large set of experimental data is fitted using as a single free parameter the mean partonic transverse momentum. The dependence of left angle k T right angle on the collision characteristics (initial energy and transverse momentum of the final photon) is much smoother when compared with similar results found in the literature using a Gaussian distribution for the partonic transverse momenta. Within the considered class of hyper-central quark potentials the one with the weaker dependence on the hyper-radius is preferred for the description of the data since it leads to the smoothest mean partonic transverse-momentum profile. We have repeated all the calculations using a two-body potential of the same form as the optimal (within the considered class) hyper-central potential in order to check if the presence of three-body forces is supported by the experimental data. Our analysis indicates that three-body forces influence significantly the form of the parton transverse-momentum distribution and consequently lead to an improved description of the considered data. (orig.)
Precise measurement of muon momenta at LEP using the L3 detector
International Nuclear Information System (INIS)
Gonzalez Romero, E.M.
1990-01-01
In this PhD report the author presents the studies and methods developed to achieve the optimization of the resolution in the momentum measurement of the L3 moun detector. Chapters 1 and 2 show the motivations to build a precision muon detector for the LEP e + e - collider. Special emphasis is applied to the study of the Higgs scalar boson search and identification and the guiding principles used to design the L3 muon detector are outlined. Chapter 3 is devoted to the description of the drift chambers. They are located in three concentric octagonal cylinders inside one solenoidal magnet, around the interaction point and coaxial with the beams. These chambers are the measuring elements of the detector. The chapter includes the description or the different tests applied to the chambers to obtain their resolution and calibration. In chapter 4 the alignment system of this chambers is described. This system is a key element to the precision of the detector, that being 12 meters long and of 12 meters of diameter has to measure the particles trajectories with precisions of just a few micrometers. Chapter 5 describes the third key piece for the detector precision, the monitoring and control system. It allows to know continually the precise values of the critical parameters of the detector. Finally in chapter 6 the author presents the results of the many test applied to the detector using cosmic rays, UV lasers and even the actual muons produced in the e + e - interactions. These tests prove that the L3 muon detector is the most precise measuring system for muon momenta installed at present in one e + e - collider ring. (Author)
Alper, B; Booth, P; Bulos, F; Carroll, L J; Damgaard, G; Duff, Brian G; Jackson, J N; Jarlskog, G; Klovning, A; Lee, W; Leistam, L; Lillethun, E; Manning, Geoffrey; Potter, K; Prentice, M; Quarrie, D; Sharp, P; Sharrock, S; von Dardel, Guy F; Weiss, J M
1973-01-01
Preliminary measurements have been made at centre of mass energies square root s=31 and 44 GeV of the pi , K and p production ratios at 90 degrees for p/sub T/ between 2.0 and 3.5 GeV/c. The (K+p)/ pi ratio is given down to p/sub T/=1.4 GeV/c. No strong energy dependence is observed for these transverse momenta. (2 refs).
International Nuclear Information System (INIS)
Abramov, V.V.; Baldin, B.Y.; Buzulutskov, A.F.
1985-01-01
Cross sections have been measured for the pair production of hadrons (π, K, p) emitted with equal momenta in opposite directions in the c.m.s. in pp collisions in the transverse-momentum region from 0.45 to 1.99 GeV/c. Data are given on the correlation of particles as a function of the quantum numbers and transverse momentum. The results are analyzed in the framework of parton models
On the Problem of High Transverse Momenta in the Interactions of Hadrons at Energies about 1016 eV
Sroka, J.; Malinowski, J.
2003-07-01
In several cosmic ray experiments with X-ray chambers exposed on mountain altitudes and in stratosphere there have been observed cases interpreted as a result of interactions, in which particles with extremely high transverse momenta are produced. Such particles could be produced in semihard parton interactions but it is known that the cross-section for such on interaction is very small. In this paper we try to find out how many particles with the highest energies in a family can have a very high pt without contradiction to the fundamental laws of physics i.e. the principles of quantum mechanics and relativistic mechanics. We formulate a simplified model of the nucleon nucleus collision and we calculate the average number of semihard interactions in nucleon air nucleus collision at 2 · 1016 eV . The calculations was made for two different sets of the model parameters. For the first we obtain one semihard interaction resulting in two partons with transverse momenta close to 20 GeV /c per one nucleon nucleus collision. For the second set we obtain one semihard interaction producing parton with transverse momenta close to 60 GeV /c per sixty collisions.
Chatrchyan, Serguei; Sirunyan, Albert M; Tumasyan, Armen; Adam, Wolfgang; Bergauer, Thomas; Dragicevic, Marko; Erö, Janos; Fabjan, Christian; Friedl, Markus; Fruehwirth, Rudolf; Ghete, Vasile Mihai; Hammer, Josef; Haensel, Stephan; Hoch, Michael; Hörmann, Natascha; Hrubec, Josef; Jeitler, Manfred; Kiesenhofer, Wolfgang; Krammer, Manfred; Liko, Dietrich; Mikulec, Ivan; Pernicka, Manfred; Rohringer, Herbert; Schöfbeck, Robert; Strauss, Josef; Taurok, Anton; Teischinger, Florian; Wagner, Philipp; Waltenberger, Wolfgang; Walzel, Gerhard; Widl, Edmund; Wulz, Claudia-Elisabeth; Mossolov, Vladimir; Shumeiko, Nikolai; Suarez Gonzalez, Juan; Benucci, Leonardo; De Wolf, Eddi A; Janssen, Xavier; Maes, Joris; Maes, Thomas; Mucibello, Luca; Ochesanu, Silvia; Roland, Benoit; Rougny, Romain; Selvaggi, Michele; Van Haevermaet, Hans; Van Mechelen, Pierre; Van Remortel, Nick; Blekman, Freya; Blyweert, Stijn; D'Hondt, Jorgen; Devroede, Olivier; Gonzalez Suarez, Rebeca; Kalogeropoulos, Alexis; Maes, Michael; Van Doninck, Walter; Van Mulders, Petra; Van Onsem, Gerrit Patrick; Villella, Ilaria; Charaf, Otman; Clerbaux, Barbara; De Lentdecker, Gilles; Dero, Vincent; Gay, Arnaud; Hammad, Gregory Habib; Hreus, Tomas; Marage, Pierre Edouard; Thomas, Laurent; Vander Velde, Catherine; Vanlaer, Pascal; Adler, Volker; Cimmino, Anna; Costantini, Silvia; Grunewald, Martin; Klein, Benjamin; Lellouch, Jérémie; Marinov, Andrey; Mccartin, Joseph; Ryckbosch, Dirk; Thyssen, Filip; Tytgat, Michael; Vanelderen, Lukas; Verwilligen, Piet; Walsh, Sinead; Zaganidis, Nicolas; Basegmez, Suzan; Bruno, Giacomo; Caudron, Julien; Ceard, Ludivine; Cortina Gil, Eduardo; De Favereau De Jeneret, Jerome; Delaere, Christophe; Favart, Denis; Giammanco, Andrea; Grégoire, Ghislain; Hollar, Jonathan; Lemaitre, Vincent; Liao, Junhui; Militaru, Otilia; Ovyn, Severine; Pagano, Davide; Pin, Arnaud; Piotrzkowski, Krzysztof; Schul, Nicolas; Beliy, Nikita; Caebergs, Thierry; Daubie, Evelyne; Alves, Gilvan; De Jesus Damiao, Dilson; Pol, Maria Elena; Henrique Gomes E Souza, Moacyr; Carvalho, Wagner; Melo Da Costa, Eliza; De Oliveira Martins, Carley; Fonseca De Souza, Sandro; Mundim, Luiz; Nogima, Helio; Oguri, Vitor; Prado Da Silva, Wanda Lucia; Santoro, Alberto; Silva Do Amaral, Sheila Mara; Sznajder, Andre; Torres Da Silva De Araujo, Felipe; De Almeida Dias, Flavia; Tomei, Thiago; De Moraes Gregores, Eduardo; Lagana, Caio; Da Cunha Marinho, Franciole; Mercadante, Pedro G; Novaes, Sergio F; Padula, Sandra; Darmenov, Nikolay; Dimitrov, Lubomir; Genchev, Vladimir; Iaydjiev, Plamen; Piperov, Stefan; Rodozov, Mircho; Stoykova, Stefka; Sultanov, Georgi; Tcholakov, Vanio; Trayanov, Rumen; Vankov, Ivan; Dimitrov, Anton; Hadjiiska, Roumyana; Karadzhinova, Aneliya; Kozhuharov, Venelin; Litov, Leander; Mateev, Matey; Pavlov, Borislav; Petkov, Peicho; Bian, Jian-Guo; Chen, Guo-Ming; Chen, He-Sheng; Jiang, Chun-Hua; Liang, Dong; Liang, Song; Meng, Xiangwei; Tao, Junquan; Wang, Jian; Wang, Jian; Wang, Xianyou; Wang, Zheng; Xiao, Hong; Xu, Ming; Zang, Jingjing; Zhang, Zhen; Ban, Yong; Guo, Shuang; Guo, Yifei; Li, Wenbo; Mao, Yajun; Qian, Si-Jin; Teng, Haiyun; Zhang, Linlin; Zhu, Bo; Zou, Wei; Cabrera, Andrés; Gomez Moreno, Bernardo; Ocampo Rios, Alberto Andres; Osorio Oliveros, Andres Felipe; Sanabria, Juan Carlos; Godinovic, Nikola; Lelas, Damir; Lelas, Karlo; Plestina, Roko; Polic, Dunja; Puljak, Ivica; Antunovic, Zeljko; Dzelalija, Mile; Brigljevic, Vuko; Duric, Senka; Kadija, Kreso; Morovic, Srecko; Attikis, Alexandros; Galanti, Mario; Mousa, Jehad; Nicolaou, Charalambos; Ptochos, Fotios; Razis, Panos A; Finger, Miroslav; Finger Jr, Michael; Assran, Yasser; Khalil, Shaaban; Mahmoud, Mohammed; Hektor, Andi; Kadastik, Mario; Müntel, Mait; Raidal, Martti; Rebane, Liis; Azzolini, Virginia; Eerola, Paula; Fedi, Giacomo; Czellar, Sandor; Härkönen, Jaakko; Heikkinen, Mika Aatos; Karimäki, Veikko; Kinnunen, Ritva; Kortelainen, Matti J; Lampén, Tapio; Lassila-Perini, Kati; Lehti, Sami; Lindén, Tomas; Luukka, Panja-Riina; Mäenpää, Teppo; Tuominen, Eija; Tuominiemi, Jorma; Tuovinen, Esa; Ungaro, Donatella; Wendland, Lauri; Banzuzi, Kukka; Korpela, Arja; Tuuva, Tuure; Sillou, Daniel; Besancon, Marc; Choudhury, Somnath; Dejardin, Marc; Denegri, Daniel; Fabbro, Bernard; Faure, Jean-Louis; Ferri, Federico; Ganjour, Serguei; Gentit, François-Xavier; Givernaud, Alain; Gras, Philippe; Hamel de Monchenault, Gautier; Jarry, Patrick; Locci, Elizabeth; Malcles, Julie; Marionneau, Matthieu; Millischer, Laurent; Rander, John; Rosowsky, André; Shreyber, Irina; Titov, Maksym; Verrecchia, Patrice; Baffioni, Stephanie; Beaudette, Florian; Benhabib, Lamia; Bianchini, Lorenzo; Bluj, Michal; Broutin, Clementine; Busson, Philippe; Charlot, Claude; Dahms, Torsten; Dobrzynski, Ludwik; Elgammal, Sherif; Granier de Cassagnac, Raphael; Haguenauer, Maurice; Miné, Philippe; Mironov, Camelia; Ochando, Christophe; Paganini, Pascal; Sabes, David; Salerno, Roberto; Sirois, Yves; Thiebaux, Christophe; Wyslouch, Bolek; Zabi, Alexandre; Agram, Jean-Laurent; Andrea, Jeremy; Bloch, Daniel; Bodin, David; Brom, Jean-Marie; Cardaci, Marco; Chabert, Eric Christian; Collard, Caroline; Conte, Eric; Drouhin, Frédéric; Ferro, Cristina; Fontaine, Jean-Charles; Gelé, Denis; Goerlach, Ulrich; Greder, Sebastien; Juillot, Pierre; Karim, Mehdi; Le Bihan, Anne-Catherine; Mikami, Yoshinari; Van Hove, Pierre; Fassi, Farida; Mercier, Damien; Baty, Clement; Beauceron, Stephanie; Beaupere, Nicolas; Bedjidian, Marc; Bondu, Olivier; Boudoul, Gaelle; Boumediene, Djamel; Brun, Hugues; Chasserat, Julien; Chierici, Roberto; Contardo, Didier; Depasse, Pierre; El Mamouni, Houmani; Fay, Jean; Gascon, Susan; Ille, Bernard; Kurca, Tibor; Le Grand, Thomas; Lethuillier, Morgan; Mirabito, Laurent; Perries, Stephane; Sordini, Viola; Tosi, Silvano; Tschudi, Yohann; Verdier, Patrice; Lomidze, David; Anagnostou, Georgios; Edelhoff, Matthias; Feld, Lutz; Heracleous, Natalie; Hindrichs, Otto; Jussen, Ruediger; Klein, Katja; Merz, Jennifer; Mohr, Niklas; Ostapchuk, Andrey; Perieanu, Adrian; Raupach, Frank; Sammet, Jan; Schael, Stefan; Sprenger, Daniel; Weber, Hendrik; Weber, Martin; Wittmer, Bruno; Ata, Metin; Bender, Walter; Dietz-Laursonn, Erik; Erdmann, Martin; Frangenheim, Jens; Hebbeker, Thomas; Hinzmann, Andreas; Hoepfner, Kerstin; Klimkovich, Tatsiana; Klingebiel, Dennis; Kreuzer, Peter; Lanske, Dankfried; Magass, Carsten; Merschmeyer, Markus; Meyer, Arnd; Papacz, Paul; Pieta, Holger; Reithler, Hans; Schmitz, Stefan Antonius; Sonnenschein, Lars; Steggemann, Jan; Teyssier, Daniel; Bontenackels, Michael; Davids, Martina; Duda, Markus; Flügge, Günter; Geenen, Heiko; Giffels, Manuel; Haj Ahmad, Wael; Heydhausen, Dirk; Kress, Thomas; Kuessel, Yvonne; Linn, Alexander; Nowack, Andreas; Perchalla, Lars; Pooth, Oliver; Rennefeld, Jörg; Sauerland, Philip; Stahl, Achim; Thomas, Maarten; Tornier, Daiske; Zoeller, Marc Henning; Aldaya Martin, Maria; Behrenhoff, Wolf; Behrens, Ulf; Bergholz, Matthias; Bethani, Agni; Borras, Kerstin; Cakir, Altan; Campbell, Alan; Castro, Elena; Dammann, Dirk; Eckerlin, Guenter; Eckstein, Doris; Flossdorf, Alexander; Flucke, Gero; Geiser, Achim; Hauk, Johannes; Jung, Hannes; Kasemann, Matthias; Katkov, Igor; Katsas, Panagiotis; Kleinwort, Claus; Kluge, Hannelies; Knutsson, Albert; Krämer, Mira; Krücker, Dirk; Kuznetsova, Ekaterina; Lange, Wolfgang; Lohmann, Wolfgang; Mankel, Rainer; Marienfeld, Markus; Melzer-Pellmann, Isabell-Alissandra; Meyer, Andreas Bernhard; Mnich, Joachim; Mussgiller, Andreas; Olzem, Jan; Pitzl, Daniel; Raspereza, Alexei; Raval, Amita; Rosin, Michele; Schmidt, Ringo; Schoerner-Sadenius, Thomas; Sen, Niladri; Spiridonov, Alexander; Stein, Matthias; Tomaszewska, Justyna; Walsh, Roberval; Wissing, Christoph; Autermann, Christian; Blobel, Volker; Bobrovskyi, Sergei; Draeger, Jula; Enderle, Holger; Gebbert, Ulla; Kaschube, Kolja; Kaussen, Gordon; Klanner, Robert; Lange, Jörn; Mura, Benedikt; Naumann-Emme, Sebastian; Nowak, Friederike; Pietsch, Niklas; Sander, Christian; Schettler, Hannes; Schleper, Peter; Schröder, Matthias; Schum, Torben; Schwandt, Joern; Stadie, Hartmut; Steinbrück, Georg; Thomsen, Jan; Barth, Christian; Bauer, Julia; Buege, Volker; Chwalek, Thorsten; De Boer, Wim; Dierlamm, Alexander; Dirkes, Guido; Feindt, Michael; Gruschke, Jasmin; Hackstein, Christoph; Hartmann, Frank; Heinrich, Michael; Held, Hauke; Hoffmann, Karl-Heinz; Honc, Simon; Komaragiri, Jyothsna Rani; Kuhr, Thomas; Martschei, Daniel; Mueller, Steffen; Müller, Thomas; Niegel, Martin; Oberst, Oliver; Oehler, Andreas; Ott, Jochen; Peiffer, Thomas; Quast, Gunter; Rabbertz, Klaus; Ratnikov, Fedor; Ratnikova, Natalia; Renz, Manuel; Saout, Christophe; Scheurer, Armin; Schieferdecker, Philipp; Schilling, Frank-Peter; Schmanau, Mike; Schott, Gregory; Simonis, Hans-Jürgen; Stober, Fred-Markus Helmut; Troendle, Daniel; Wagner-Kuhr, Jeannine; Weiler, Thomas; Zeise, Manuel; Zhukov, Valery; Ziebarth, Eva Barbara; Daskalakis, Georgios; Geralis, Theodoros; Kesisoglou, Stilianos; Kyriakis, Aristotelis; Loukas, Demetrios; Manolakos, Ioannis; Markou, Athanasios; Markou, Christos; Mavrommatis, Charalampos; Ntomari, Eleni; Petrakou, Eleni; Gouskos, Loukas; Mertzimekis, Theodoros; Panagiotou, Apostolos; Stiliaris, Efstathios; Evangelou, Ioannis; Foudas, Costas; Kokkas, Panagiotis; Manthos, Nikolaos; Papadopoulos, Ioannis; Patras, Vaios; Triantis, Frixos A; Aranyi, Attila; Bencze, Gyorgy; Boldizsar, Laszlo; Hajdu, Csaba; Hidas, Pàl; Horvath, Dezso; Kapusi, Anita; Krajczar, Krisztian; Sikler, Ferenc; Veres, Gabor Istvan; Vesztergombi, Gyorgy; Beni, Noemi; Molnar, Jozsef; Palinkas, Jozsef; Szillasi, Zoltan; Veszpremi, Viktor; Raics, Peter; Trocsanyi, Zoltan Laszlo; Ujvari, Balazs; Bansal, Sunil; Beri, Suman Bala; Bhatnagar, Vipin; Dhingra, Nitish; Gupta, Ruchi; Jindal, Monika; Kaur, Manjit; Kohli, Jatinder Mohan; Mehta, Manuk Zubin; Nishu, Nishu; Saini, Lovedeep Kaur; Sharma, Archana; Singh, Anil; Singh, Jasbir; Singh, Supreet Pal; Ahuja, Sudha; Bhattacharya, Satyaki; Choudhary, Brajesh C; Gupta, Pooja; Jain, Sandhya; Jain, Shilpi; Kumar, Ashok; Ranjan, Kirti; Shivpuri, Ram Krishen; Choudhury, Rajani Kant; Dutta, Dipanwita; Kailas, Swaminathan; Kumar, Vineet; Mohanty, Ajit Kumar; Pant, Lalit Mohan; Shukla, Prashant; Aziz, Tariq; Guchait, Monoranjan; Gurtu, Atul; Maity, Manas; Majumder, Devdatta; Majumder, Gobinda; Mazumdar, Kajari; Mohanty, Gagan Bihari; Saha, Anirban; Sudhakar, Katta; Wickramage, Nadeesha; Banerjee, Sudeshna; Dugad, Shashikant; Mondal, Naba Kumar; Arfaei, Hessamaddin; Bakhshiansohi, Hamed; Etesami, Seyed Mohsen; Fahim, Ali; Hashemi, Majid; Jafari, Abideh; Khakzad, Mohsen; Mohammadi, Abdollah; Mohammadi Najafabadi, Mojtaba; Paktinat Mehdiabadi, Saeid; Safarzadeh, Batool; Zeinali, Maryam; Abbrescia, Marcello; Barbone, Lucia; Calabria, Cesare; Colaleo, Anna; Creanza, Donato; De Filippis, Nicola; De Palma, Mauro; Fiore, Luigi; Iaselli, Giuseppe; Lusito, Letizia; Maggi, Giorgio; Maggi, Marcello; Manna, Norman; Marangelli, Bartolomeo; My, Salvatore; Nuzzo, Salvatore; Pacifico, Nicola; Pierro, Giuseppe Antonio; Pompili, Alexis; Pugliese, Gabriella; Romano, Francesco; Roselli, Giuseppe; Selvaggi, Giovanna; Silvestris, Lucia; Trentadue, Raffaello; Tupputi, Salvatore; Zito, Giuseppe; Abbiendi, Giovanni; Benvenuti, Alberto; Bonacorsi, Daniele; Braibant-Giacomelli, Sylvie; Brigliadori, Luca; Capiluppi, Paolo; Castro, Andrea; Cavallo, Francesca Romana; Cuffiani, Marco; Dallavalle, Gaetano-Marco; Fabbri, Fabrizio; Fanfani, Alessandra; Fasanella, Daniele; Giacomelli, Paolo; Giunta, Marina; Marcellini, Stefano; Masetti, Gianni; Meneghelli, Marco; Montanari, Alessandro; Navarria, Francesco; Odorici, Fabrizio; Perrotta, Andrea; Primavera, Federica; Rossi, Antonio; Rovelli, Tiziano; Siroli, Gianni; Travaglini, Riccardo; Albergo, Sebastiano; Cappello, Gigi; Chiorboli, Massimiliano; Costa, Salvatore; Tricomi, Alessia; Tuve, Cristina; Barbagli, Giuseppe; Ciulli, Vitaliano; Civinini, Carlo; D'Alessandro, Raffaello; Focardi, Ettore; Frosali, Simone; Gallo, Elisabetta; Gonzi, Sandro; Lenzi, Piergiulio; Meschini, Marco; Paoletti, Simone; Sguazzoni, Giacomo; Tropiano, Antonio; Benussi, Luigi; Bianco, Stefano; Colafranceschi, Stefano; Fabbri, Franco; Piccolo, Davide; Fabbricatore, Pasquale; Musenich, Riccardo; Benaglia, Andrea; De Guio, Federico; Di Matteo, Leonardo; Gennai, Simone; Ghezzi, Alessio; Malvezzi, Sandra; Martelli, Arabella; Massironi, Andrea; Menasce, Dario; Moroni, Luigi; Paganoni, Marco; Pedrini, Daniele; Ragazzi, Stefano; Redaelli, Nicola; Sala, Silvano; Tabarelli de Fatis, Tommaso; Buontempo, Salvatore; Carrillo Montoya, Camilo Andres; Cavallo, Nicola; De Cosa, Annapaola; Fabozzi, Francesco; Iorio, Alberto Orso Maria; Lista, Luca; Merola, Mario; Paolucci, Pierluigi; Azzi, Patrizia; Bacchetta, Nicola; Bellan, Paolo; Bisello, Dario; Branca, Antonio; Carlin, Roberto; Checchia, Paolo; De Mattia, Marco; Dorigo, Tommaso; Dosselli, Umberto; Gasparini, Fabrizio; Gasparini, Ugo; Gozzelino, Andrea; Lacaprara, Stefano; Lazzizzera, Ignazio; Margoni, Martino; Mazzucato, Mirco; Meneguzzo, Anna Teresa; Nespolo, Massimo; Perrozzi, Luca; Pozzobon, Nicola; Ronchese, Paolo; Simonetto, Franco; Torassa, Ezio; Tosi, Mia; Triossi, Andrea; Vanini, Sara; Zotto, Pierluigi; Zumerle, Gianni; Baesso, Paolo; Berzano, Umberto; Ratti, Sergio P; Riccardi, Cristina; Torre, Paola; Vitulo, Paolo; Viviani, Claudio; Biasini, Maurizio; Bilei, Gian Mario; Caponeri, Benedetta; Fanò, Livio; Lariccia, Paolo; Lucaroni, Andrea; Mantovani, Giancarlo; Menichelli, Mauro; Nappi, Aniello; Romeo, Francesco; Santocchia, Attilio; Taroni, Silvia; Valdata, Marisa; Azzurri, Paolo; Bagliesi, Giuseppe; Bernardini, Jacopo; Boccali, Tommaso; Broccolo, Giuseppe; Castaldi, Rino; D'Agnolo, Raffaele Tito; Dell'Orso, Roberto; Fiori, Francesco; Foà, Lorenzo; Giassi, Alessandro; Kraan, Aafke; Ligabue, Franco; Lomtadze, Teimuraz; Martini, Luca; Messineo, Alberto; Palla, Fabrizio; Peruzzi, Marco; Segneri, Gabriele; Serban, Alin Titus; Spagnolo, Paolo; Tenchini, Roberto; Tonelli, Guido; Venturi, Andrea; Verdini, Piero Giorgio; Barone, Luciano; Cavallari, Francesca; Del Re, Daniele; Di Marco, Emanuele; Diemoz, Marcella; Franci, Daniele; Grassi, Marco; Longo, Egidio; Nourbakhsh, Shervin; Organtini, Giovanni; Pandolfi, Francesco; Paramatti, Riccardo; Rahatlou, Shahram; Rovelli, Chiara; Amapane, Nicola; Arcidiacono, Roberta; Argiro, Stefano; Arneodo, Michele; Biino, Cristina; Botta, Cristina; Cartiglia, Nicolo; Castello, Roberto; Costa, Marco; Demaria, Natale; Graziano, Alberto; Mariotti, Chiara; Marone, Matteo; Maselli, Silvia; Migliore, Ernesto; Mila, Giorgia; Monaco, Vincenzo; Musich, Marco; Obertino, Maria Margherita; Pastrone, Nadia; Pelliccioni, Mario; Romero, Alessandra; Ruspa, Marta; Sacchi, Roberto; Sola, Valentina; Solano, Ada; Staiano, Amedeo; Vilela Pereira, Antonio; Belforte, Stefano; Cossutti, Fabio; Della Ricca, Giuseppe; Gobbo, Benigno; Montanino, Damiana; Penzo, Aldo; Heo, Seong Gu; Nam, Soon-Kwon; Chang, Sunghyun; Chung, Jin Hyuk; Kim, Dong Hee; Kim, Gui Nyun; Kim, Ji Eun; Kong, Dae Jung; Park, Hyangkyu; Ro, Sang-Ryul; Son, Dohhee; Son, Dong-Chul; Son, Taejin; Kim, Jaeho; Kim, Jae Yool; Song, Sanghyeon; Choi, Suyong; Hong, Byung-Sik; Jeong, Min-Soo; Jo, Mihee; Kim, Hyunchul; Kim, Ji Hyun; Kim, Tae Jeong; Lee, Kyong Sei; Moon, Dong Ho; Park, Sung Keun; Rhee, Han-Bum; Seo, Eunsung; Shin, Seungsu; Sim, Kwang Souk; Choi, Minkyoo; Kang, Seokon; Kim, Hyunyong; Park, Chawon; Park, Inkyu; Park, Sangnam; Ryu, Geonmo; Choi, Young-Il; Choi, Young Kyu; Goh, Junghwan; Kim, Min Suk; Kwon, Eunhyang; Lee, Jongseok; Lee, Sungeun; Seo, Hyunkwan; Yu, Intae; Bilinskas, Mykolas Jurgis; Grigelionis, Ignas; Janulis, Mindaugas; Martisiute, Dalia; Petrov, Pavel; Sabonis, Tomas; Castilla-Valdez, Heriberto; De La Cruz-Burelo, Eduard; Heredia-de La Cruz, Ivan; Lopez-Fernandez, Ricardo; Magaña Villalba, Ricardo; Sánchez-Hernández, Alberto; Villasenor-Cendejas, Luis Manuel; Carrillo Moreno, Salvador; Vazquez Valencia, Fabiola; Salazar Ibarguen, Humberto Antonio; Casimiro Linares, Edgar; Morelos Pineda, Antonio; Reyes-Santos, Marco A; Krofcheck, David; Tam, Jason; Yiu, Chun Hin; Butler, Philip H; Doesburg, Robert; Silverwood, Hamish; Ahmad, Muhammad; Ahmed, Ijaz; Asghar, Muhammad Irfan; Hoorani, Hafeez R; Khan, Wajid Ali; Khurshid, Taimoor; Qazi, Shamona; Brona, Grzegorz; Cwiok, Mikolaj; Dominik, Wojciech; Doroba, Krzysztof; Kalinowski, Artur; Konecki, Marcin; Krolikowski, Jan; Frueboes, Tomasz; Gokieli, Ryszard; Górski, Maciej; Kazana, Malgorzata; Nawrocki, Krzysztof; Romanowska-Rybinska, Katarzyna; Szleper, Michal; Wrochna, Grzegorz; Zalewski, Piotr; Almeida, Nuno; Bargassa, Pedrame; David Tinoco Mendes, Andre; Faccioli, Pietro; Ferreira Parracho, Pedro Guilherme; Gallinaro, Michele; Musella, Pasquale; Nayak, Aruna; Ribeiro, Pedro Quinaz; Seixas, Joao; Varela, Joao; Afanasiev, Serguei; Belotelov, Ivan; Bunin, Pavel; Golutvin, Igor; Kamenev, Alexey; Karjavin, Vladimir; Kozlov, Guennady; Lanev, Alexander; Moisenz, Petr; Palichik, Vladimir; Perelygin, Victor; Shmatov, Sergey; Smirnov, Vitaly; Volodko, Anton; Zarubin, Anatoli; Golovtsov, Victor; Ivanov, Yury; Kim, Victor; Levchenko, Petr; Murzin, Victor; Oreshkin, Vadim; Smirnov, Igor; Sulimov, Valentin; Uvarov, Lev; Vavilov, Sergey; Vorobyev, Alexey; Vorobyev, Andrey; Andreev, Yuri; Dermenev, Alexander; Gninenko, Sergei; Golubev, Nikolai; Kirsanov, Mikhail; Krasnikov, Nikolai; Matveev, Viktor; Pashenkov, Anatoli; Toropin, Alexander; Troitsky, Sergey; Epshteyn, Vladimir; Gavrilov, Vladimir; Kaftanov, Vitali; Kossov, Mikhail; Krokhotin, Andrey; Lychkovskaya, Natalia; Popov, Vladimir; Safronov, Grigory; Semenov, Sergey; Stolin, Viatcheslav; Vlasov, Evgueni; Zhokin, Alexander; Boos, Edouard; Dubinin, Mikhail; Dudko, Lev; Ershov, Alexander; Gribushin, Andrey; Kodolova, Olga; Lokhtin, Igor; Markina, Anastasia; Obraztsov, Stepan; Perfilov, Maxim; Petrushanko, Sergey; Sarycheva, Ludmila; Savrin, Viktor; Snigirev, Alexander; Andreev, Vladimir; Azarkin, Maksim; Dremin, Igor; Kirakosyan, Martin; Leonidov, Andrey; Rusakov, Sergey V; Vinogradov, Alexey; Azhgirey, Igor; Bitioukov, Sergei; Grishin, Viatcheslav; Kachanov, Vassili; Konstantinov, Dmitri; Korablev, Andrey; Krychkine, Victor; Petrov, Vladimir; Ryutin, Roman; Slabospitsky, Sergey; Sobol, Andrei; Tourtchanovitch, Leonid; Troshin, Sergey; Tyurin, Nikolay; Uzunian, Andrey; Volkov, Alexey; Adzic, Petar; Djordjevic, Milos; Krpic, Dragomir; Milosevic, Jovan; Aguilar-Benitez, Manuel; Alcaraz Maestre, Juan; Arce, Pedro; Battilana, Carlo; Calvo, Enrique; Cepeda, Maria; Cerrada, Marcos; Chamizo Llatas, Maria; Colino, Nicanor; De La Cruz, Begona; Delgado Peris, Antonio; Diez Pardos, Carmen; Domínguez Vázquez, Daniel; Fernandez Bedoya, Cristina; Fernández Ramos, Juan Pablo; Ferrando, Antonio; Flix, Jose; Fouz, Maria Cruz; Garcia-Abia, Pablo; Gonzalez Lopez, Oscar; Goy Lopez, Silvia; Hernandez, Jose M; Josa, Maria Isabel; Merino, Gonzalo; Puerta Pelayo, Jesus; Redondo, Ignacio; Romero, Luciano; Santaolalla, Javier; Senghi Soares, Mara; Willmott, Carlos; Albajar, Carmen; Codispoti, Giuseppe; de Trocóniz, Jorge F; Cuevas, Javier; Fernandez Menendez, Javier; Folgueras, Santiago; Gonzalez Caballero, Isidro; Lloret Iglesias, Lara; Vizan Garcia, Jesus Manuel; Brochero Cifuentes, Javier Andres; Cabrillo, Iban Jose; Calderon, Alicia; Chuang, Shan-Huei; Duarte Campderros, Jordi; Felcini, Marta; Fernandez, Marcos; Gomez, Gervasio; Gonzalez Sanchez, Javier; Jorda, Clara; Lobelle Pardo, Patricia; Lopez Virto, Amparo; Marco, Jesus; Marco, Rafael; Martinez Rivero, Celso; Matorras, Francisco; Munoz Sanchez, Francisca Javiela; Piedra Gomez, Jonatan; Rodrigo, Teresa; Rodríguez-Marrero, Ana Yaiza; Ruiz-Jimeno, Alberto; Scodellaro, Luca; Sobron Sanudo, Mar; Vila, Ivan; Vilar Cortabitarte, Rocio; Abbaneo, Duccio; Auffray, Etiennette; Auzinger, Georg; Baillon, Paul; Ball, Austin; Barney, David; Bell, Alan James; Benedetti, Daniele; Bernet, Colin; Bialas, Wojciech; Bloch, Philippe; Bocci, Andrea; Bolognesi, Sara; Bona, Marcella; Breuker, Horst; Bunkowski, Karol; Camporesi, Tiziano; Cerminara, Gianluca; Coarasa Perez, Jose Antonio; Curé, Benoît; D'Enterria, David; De Roeck, Albert; Di Guida, Salvatore; Dupont-Sagorin, Niels; Elliott-Peisert, Anna; Frisch, Benjamin; Funk, Wolfgang; Gaddi, Andrea; Georgiou, Georgios; Gerwig, Hubert; Gigi, Dominique; Gill, Karl; Giordano, Domenico; Glege, Frank; Gomez-Reino Garrido, Robert; Gouzevitch, Maxime; Govoni, Pietro; Gowdy, Stephen; Guiducci, Luigi; Hansen, Magnus; Hartl, Christian; Harvey, John; Hegeman, Jeroen; Hegner, Benedikt; Hoffmann, Hans Falk; Honma, Alan; Innocente, Vincenzo; Janot, Patrick; Kaadze, Ketino; Karavakis, Edward; Lecoq, Paul; Lourenco, Carlos; Maki, Tuula; Malberti, Martina; Malgeri, Luca; Mannelli, Marcello; Masetti, Lorenzo; Maurisset, Aurelie; Meijers, Frans; Mersi, Stefano; Meschi, Emilio; Moser, Roland; Mozer, Matthias Ulrich; Mulders, Martijn; Nesvold, Erik; Nguyen, Matthew; Orimoto, Toyoko; Orsini, Luciano; Perez, Emmanuelle; Petrilli, Achille; Pfeiffer, Andreas; Pierini, Maurizio; Pimiä, Martti; Piparo, Danilo; Polese, Giovanni; Racz, Attila; Rodrigues Antunes, Joao; Rolandi, Gigi; Rommerskirchen, Tanja; Rovere, Marco; Sakulin, Hannes; Schäfer, Christoph; Schwick, Christoph; Segoni, Ilaria; Sharma, Archana; Siegrist, Patrice; Simon, Michal; Sphicas, Paraskevas; Spiropulu, Maria; Stoye, Markus; Tadel, Matevz; Tropea, Paola; Tsirou, Andromachi; Vichoudis, Paschalis; Voutilainen, Mikko; Zeuner, Wolfram Dietrich; Bertl, Willi; Deiters, Konrad; Erdmann, Wolfram; Gabathuler, Kurt; Horisberger, Roland; Ingram, Quentin; Kaestli, Hans-Christian; König, Stefan; Kotlinski, Danek; Langenegger, Urs; Meier, Frank; Renker, Dieter; Rohe, Tilman; Sibille, Jennifer; Starodumov, Andrei; Bortignon, Pierluigi; Caminada, Lea; Chanon, Nicolas; Chen, Zhiling; Cittolin, Sergio; Dissertori, Günther; Dittmar, Michael; Eugster, Jürg; Freudenreich, Klaus; Grab, Christoph; Hervé, Alain; Hintz, Wieland; Lecomte, Pierre; Lustermann, Werner; Marchica, Carmelo; Martinez Ruiz del Arbol, Pablo; Meridiani, Paolo; Milenovic, Predrag; Moortgat, Filip; Nägeli, Christoph; Nef, Pascal; Nessi-Tedaldi, Francesca; Pape, Luc; Pauss, Felicitas; Punz, Thomas; Rizzi, Andrea; Ronga, Frederic Jean; Rossini, Marco; Sala, Leonardo; Sanchez, Ann - Karin; Sawley, Marie-Christine; Stieger, Benjamin; Tauscher, Ludwig; Thea, Alessandro; Theofilatos, Konstantinos; Treille, Daniel; Urscheler, Christina; Wallny, Rainer; Weber, Matthias; Wehrli, Lukas; Weng, Joanna; Aguilo, Ernest; Amsler, Claude; Chiochia, Vincenzo; De Visscher, Simon; Favaro, Carlotta; Ivova Rikova, Mirena; Millan Mejias, Barbara; Otiougova, Polina; Regenfus, Christian; Robmann, Peter; Schmidt, Alexander; Snoek, Hella; Chang, Yuan-Hann; Chen, Kuan-Hsin; Dutta, Suchandra; Kuo, Chia-Ming; Li, Syue-Wei; Lin, Willis; Liu, Zong-Kai; Lu, Yun-Ju; Mekterovic, Darko; Volpe, Roberta; Wu, Jing-Han; Yu, Shin-Shan; Bartalini, Paolo; Chang, Paoti; Chang, You-Hao; Chang, Yu-Wei; Chao, Yuan; Chen, Kai-Feng; Hou, George Wei-Shu; Hsiung, Yee; Kao, Kai-Yi; Lei, Yeong-Jyi; Lu, Rong-Shyang; Shiu, Jing-Ge; Tzeng, Yeng-Ming; Wang, Minzu; Adiguzel, Aytul; Bakirci, Mustafa Numan; Cerci, Salim; Dozen, Candan; Dumanoglu, Isa; Eskut, Eda; Girgis, Semiray; Gokbulut, Gul; Hos, Ilknur; Kangal, Evrim Ersin; Kayis Topaksu, Aysel; Onengut, Gulsen; Ozdemir, Kadri; Ozturk, Sertac; Polatoz, Ayse; Sogut, Kenan; Sunar Cerci, Deniz; Tali, Bayram; Topakli, Huseyin; Uzun, Dilber; Vergili, Latife Nukhet; Vergili, Mehmet; Akin, Ilina Vasileva; Aliev, Takhmasib; Bilmis, Selcuk; Deniz, Muhammed; Gamsizkan, Halil; Guler, Ali Murat; Ocalan, Kadir; Ozpineci, Altug; Serin, Meltem; Sever, Ramazan; Surat, Ugur Emrah; Yildirim, Eda; Zeyrek, Mehmet; Deliomeroglu, Mehmet; Demir, Durmus; Gülmez, Erhan; Isildak, Bora; Kaya, Mithat; Kaya, Ozlem; Ozkorucuklu, Suat; Sonmez, Nasuf; Levchuk, Leonid; Bostock, Francis; Brooke, James John; Cheng, Teh Lee; Clement, Emyr; Cussans, David; Frazier, Robert; Goldstein, Joel; Grimes, Mark; Hansen, Maria; Hartley, Dominic; Heath, Greg P; Heath, Helen F; Kreczko, Lukasz; Metson, Simon; Newbold, Dave M; Nirunpong, Kachanon; Poll, Anthony; Senkin, Sergey; Smith, Vincent J; Ward, Simon; Basso, Lorenzo; Bell, Ken W; Belyaev, Alexander; Brew, Christopher; Brown, Robert M; Camanzi, Barbara; Cockerill, David JA; Coughlan, John A; Harder, Kristian; Harper, Sam; Jackson, James; Kennedy, Bruce W; Olaiya, Emmanuel; Petyt, David; Radburn-Smith, Benjamin Charles; Shepherd-Themistocleous, Claire; Tomalin, Ian R; Womersley, William John; Worm, Steven; Bainbridge, Robert; Ball, Gordon; Ballin, Jamie; Beuselinck, Raymond; Buchmuller, Oliver; Colling, David; Cripps, Nicholas; Cutajar, Michael; Davies, Gavin; Della Negra, Michel; Ferguson, William; Fulcher, Jonathan; Futyan, David; Gilbert, Andrew; Guneratne Bryer, Arlo; Hall, Geoffrey; Hatherell, Zoe; Hays, Jonathan; Iles, Gregory; Jarvis, Martyn; Karapostoli, Georgia; Lyons, Louis; MacEvoy, Barry C; Magnan, Anne-Marie; Marrouche, Jad; Mathias, Bryn; Nandi, Robin; Nash, Jordan; Nikitenko, Alexander; Papageorgiou, Anastasios; Pesaresi, Mark; Petridis, Konstantinos; Pioppi, Michele; Raymond, David Mark; Rogerson, Samuel; Rompotis, Nikolaos; Rose, Andrew; Ryan, Matthew John; Seez, Christopher; Sharp, Peter; Sparrow, Alex; Tapper, Alexander; Tourneur, Stephane; Vazquez Acosta, Monica; Virdee, Tejinder; Wakefield, Stuart; Wardle, Nicholas; Wardrope, David; Whyntie, Tom; Barrett, Matthew; Chadwick, Matthew; Cole, Joanne; Hobson, Peter R; Khan, Akram; Kyberd, Paul; Leslie, Dawn; Martin, William; Reid, Ivan; Teodorescu, Liliana; Hatakeyama, Kenichi; Bose, Tulika; Carrera Jarrin, Edgar; Fantasia, Cory; Heister, Arno; St John, Jason; Lawson, Philip; Lazic, Dragoslav; Rohlf, James; Sperka, David; Sulak, Lawrence; Avetisyan, Aram; Bhattacharya, Saptaparna; Chou, John Paul; Cutts, David; Ferapontov, Alexey; Heintz, Ulrich; Jabeen, Shabnam; Kukartsev, Gennadiy; Landsberg, Greg; Narain, Meenakshi; Nguyen, Duong; Segala, Michael; Sinthuprasith, Tutanon; Speer, Thomas; Tsang, Ka Vang; Breedon, Richard; Calderon De La Barca Sanchez, Manuel; Chauhan, Sushil; Chertok, Maxwell; Conway, John; Cox, Peter Timothy; Dolen, James; Erbacher, Robin; Friis, Evan; Ko, Winston; Kopecky, Alexandra; Lander, Richard; Liu, Haidong; Maruyama, Sho; Miceli, Tia; Nikolic, Milan; Pellett, Dave; Robles, Jorge; Salur, Sevil; Schwarz, Thomas; Searle, Matthew; Smith, John; Squires, Michael; Tripathi, Mani; Vasquez Sierra, Ricardo; Veelken, Christian; Andreev, Valeri; Arisaka, Katsushi; Cline, David; Cousins, Robert; Deisher, Amanda; Duris, Joseph; Erhan, Samim; Farrell, Chris; Hauser, Jay; Ignatenko, Mikhail; Jarvis, Chad; Plager, Charles; Rakness, Gregory; Schlein, Peter; Tucker, Jordan; Valuev, Vyacheslav; Babb, John; Chandra, Avdhesh; Clare, Robert; Ellison, John Anthony; Gary, J William; Giordano, Ferdinando; Hanson, Gail; Jeng, Geng-Yuan; Kao, Shih-Chuan; Liu, Feng; Liu, Hongliang; Long, Owen Rosser; Luthra, Arun; Nguyen, Harold; Shen, Benjamin C; Stringer, Robert; Sturdy, Jared; Sumowidagdo, Suharyo; Wilken, Rachel; Wimpenny, Stephen; Andrews, Warren; Branson, James G; Cerati, Giuseppe Benedetto; Sudano, Elizabeth; Evans, David; Golf, Frank; Holzner, André; Kelley, Ryan; Lebourgeois, Matthew; Letts, James; Mangano, Boris; Padhi, Sanjay; Palmer, Christopher; Petrucciani, Giovanni; Pi, Haifeng; Pieri, Marco; Ranieri, Riccardo; Sani, Matteo; Sharma, Vivek; Simon, Sean; Tu, Yanjun; Vartak, Adish; Wasserbaech, Steven; Würthwein, Frank; Yagil, Avraham; Yoo, Jaehyeok; Barge, Derek; Bellan, Riccardo; Campagnari, Claudio; D'Alfonso, Mariarosaria; Danielson, Thomas; Flowers, Kristen; Geffert, Paul; Incandela, Joe; Justus, Christopher; Kalavase, Puneeth; Koay, Sue Ann; Kovalskyi, Dmytro; Krutelyov, Vyacheslav; Lowette, Steven; Mccoll, Nickolas; Pavlunin, Viktor; Rebassoo, Finn; Ribnik, Jacob; Richman, Jeffrey; Rossin, Roberto; Stuart, David; To, Wing; Vlimant, Jean-Roch; Apresyan, Artur; Bornheim, Adolf; Bunn, Julian; Chen, Yi; Gataullin, Marat; Ma, Yousi; Mott, Alexander; Newman, Harvey B; Rogan, Christopher; Shin, Kyoungha; Timciuc, Vladlen; Traczyk, Piotr; Veverka, Jan; Wilkinson, Richard; Yang, Yong; Zhu, Ren-Yuan; Akgun, Bora; Carroll, Ryan; Ferguson, Thomas; Iiyama, Yutaro; Jang, Dong Wook; Jun, Soon Yung; Liu, Yueh-Feng; Paulini, Manfred; Russ, James; Vogel, Helmut; Vorobiev, Igor; Cumalat, John Perry; Dinardo, Mauro Emanuele; Drell, Brian Robert; Edelmaier, Christopher; Ford, William T; Gaz, Alessandro; Heyburn, Bernadette; Luiggi Lopez, Eduardo; Nauenberg, Uriel; Smith, James; Stenson, Kevin; Ulmer, Keith; Wagner, Stephen Robert; Zang, Shi-Lei; Agostino, Lorenzo; Alexander, James; Cassel, David; Chatterjee, Avishek; Das, Souvik; Eggert, Nicholas; Gibbons, Lawrence Kent; Heltsley, Brian; Hopkins, Walter; Khukhunaishvili, Aleko; Kreis, Benjamin; Nicolas Kaufman, Gala; Patterson, Juliet Ritchie; Puigh, Darren; Ryd, Anders; Salvati, Emmanuele; Shi, Xin; Sun, Werner; Teo, Wee Don; Thom, Julia; Thompson, Joshua; Vaughan, Jennifer; Weng, Yao; Winstrom, Lucas; Wittich, Peter; Biselli, Angela; Cirino, Guy; Winn, Dave; Abdullin, Salavat; Albrow, Michael; Anderson, Jacob; Apollinari, Giorgio; Atac, Muzaffer; Bakken, Jon Alan; Banerjee, Sunanda; Bauerdick, Lothar AT; Beretvas, Andrew; Berryhill, Jeffrey; Bhat, Pushpalatha C; Bloch, Ingo; Borcherding, Frederick; Burkett, Kevin; Butler, Joel Nathan; Chetluru, Vasundhara; Cheung, Harry; Chlebana, Frank; Cihangir, Selcuk; Cooper, William; Eartly, David P; Elvira, Victor Daniel; Esen, Selda; Fisk, Ian; Freeman, Jim; Gao, Yanyan; Gottschalk, Erik; Green, Dan; Gunthoti, Kranti; Gutsche, Oliver; Hanlon, Jim; Harris, Robert M; Hirschauer, James; Hooberman, Benjamin; Jensen, Hans; Johnson, Marvin; Joshi, Umesh; Khatiwada, Rakshya; Klima, Boaz; Kousouris, Konstantinos; Kunori, Shuichi; Kwan, Simon; Leonidopoulos, Christos; Limon, Peter; Lincoln, Don; Lipton, Ron; Lykken, Joseph; Maeshima, Kaori; Marraffino, John Michael; Mason, David; McBride, Patricia; Miao, Ting; Mishra, Kalanand; Mrenna, Stephen; Musienko, Yuri; Newman-Holmes, Catherine; O'Dell, Vivian; Pordes, Ruth; Prokofyev, Oleg; Saoulidou, Niki; Sexton-Kennedy, Elizabeth; Sharma, Seema; Spalding, William J; Spiegel, Leonard; Tan, Ping; Taylor, Lucas; Tkaczyk, Slawek; Uplegger, Lorenzo; Vaandering, Eric Wayne; Vidal, Richard; Whitmore, Juliana; Wu, Weimin; Yang, Fan; Yumiceva, Francisco; Yun, Jae Chul; Acosta, Darin; Avery, Paul; Bourilkov, Dimitri; Chen, Mingshui; De Gruttola, Michele; Di Giovanni, Gian Piero; Dobur, Didar; Drozdetskiy, Alexey; Field, Richard D; Fisher, Matthew; Fu, Yu; Furic, Ivan-Kresimir; Gartner, Joseph; Kim, Bockjoo; Konigsberg, Jacobo; Korytov, Andrey; Kropivnitskaya, Anna; Kypreos, Theodore; Matchev, Konstantin; Mitselmakher, Guenakh; Muniz, Lana; Prescott, Craig; Remington, Ronald; Schmitt, Michael Houston; Scurlock, Bobby; Sellers, Paul; Skhirtladze, Nikoloz; Snowball, Matthew; Wang, Dayong; Yelton, John; Zakaria, Mohammed; Ceron, Cristobal; Gaultney, Vanessa; Kramer, Laird; Lebolo, Luis Miguel; Linn, Stephan; Markowitz, Pete; Martinez, German; Mesa, Dalgis; Rodriguez, Jorge Luis; Adams, Todd; Askew, Andrew; Bochenek, Joseph; Chen, Jie; Diamond, Brendan; Gleyzer, Sergei V; Haas, Jeff; Hagopian, Sharon; Hagopian, Vasken; Jenkins, Merrill; Johnson, Kurtis F; Prosper, Harrison; Quertenmont, Loic; Sekmen, Sezen; Veeraraghavan, Venkatesh; Baarmand, Marc M; Dorney, Brian; Guragain, Samir; Hohlmann, Marcus; Kalakhety, Himali; Ralich, Robert; Vodopiyanov, Igor; Adams, Mark Raymond; Anghel, Ioana Maria; Apanasevich, Leonard; Bai, Yuting; Bazterra, Victor Eduardo; Betts, Russell Richard; Callner, Jeremy; Cavanaugh, Richard; Dragoiu, Cosmin; Gauthier, Lucie; Gerber, Cecilia Elena; Hamdan, Saleh; Hofman, David Jonathan; Khalatyan, Samvel; Kunde, Gerd J; Lacroix, Florent; Malek, Magdalena; O'Brien, Christine; Silvestre, Catherine; Smoron, Agata; Strom, Derek; Varelas, Nikos; Akgun, Ugur; Albayrak, Elif Asli; Bilki, Burak; Clarida, Warren; Duru, Firdevs; Lae, Chung Khim; McCliment, Edward; Merlo, Jean-Pierre; Mermerkaya, Hamit; Mestvirishvili, Alexi; Moeller, Anthony; Nachtman, Jane; Newsom, Charles Ray; Norbeck, Edwin; Olson, Jonathan; Onel, Yasar; Ozok, Ferhat; Sen, Sercan; Wetzel, James; Yetkin, Taylan; Yi, Kai; Barnett, Bruce Arnold; Blumenfeld, Barry; Bonato, Alessio; Eskew, Christopher; Fehling, David; Giurgiu, Gavril; Gritsan, Andrei; Guo, Zijin; Hu, Guofan; Maksimovic, Petar; Rappoccio, Salvatore; Swartz, Morris; Tran, Nhan Viet; Whitbeck, Andrew; Baringer, Philip; Bean, Alice; Benelli, Gabriele; Grachov, Oleg; Kenny Iii, Raymond Patrick; Murray, Michael; Noonan, Daniel; Sanders, Stephen; Wood, Jeffrey Scott; Zhukova, Victoria; Barfuss, Anne-fleur; Bolton, Tim; Chakaberia, Irakli; Ivanov, Andrew; Khalil, Sadia; Makouski, Mikhail; Maravin, Yurii; Shrestha, Shruti; Svintradze, Irakli; Wan, Zongru; Gronberg, Jeffrey; Lange, David; Wright, Douglas; Baden, Drew; Boutemeur, Madjid; Eno, Sarah Catherine; Ferencek, Dinko; Gomez, Jaime; Hadley, Nicholas John; Kellogg, Richard G; Kirn, Malina; Lu, Ying; Mignerey, Alice; Rossato, Kenneth; Rumerio, Paolo; Santanastasio, Francesco; Skuja, Andris; Temple, Jeffrey; Tonjes, Marguerite; Tonwar, Suresh C; Twedt, Elizabeth; Alver, Burak; Bauer, Gerry; Bendavid, Joshua; Busza, Wit; Butz, Erik; Cali, Ivan Amos; Chan, Matthew; Dutta, Valentina; Everaerts, Pieter; Gomez Ceballos, Guillelmo; Goncharov, Maxim; Hahn, Kristan Allan; Harris, Philip; Kim, Yongsun; Klute, Markus; Lee, Yen-Jie; Li, Wei; Loizides, Constantinos; Luckey, Paul David; Ma, Teng; Nahn, Steve; Paus, Christoph; Ralph, Duncan; Roland, Christof; Roland, Gunther; Rudolph, Matthew; Stephans, George; Stöckli, Fabian; Sumorok, Konstanty; Sung, Kevin; Wenger, Edward Allen; Xie, Si; Yang, Mingming; Yilmaz, Yetkin; Yoon, Sungho; Zanetti, Marco; Cooper, Seth; Cushman, Priscilla; Dahmes, Bryan; De Benedetti, Abraham; Dudero, Phillip Russell; Franzoni, Giovanni; Haupt, Jason; Klapoetke, Kevin; Kubota, Yuichi; Mans, Jeremy; Rekovic, Vladimir; Rusack, Roger; Sasseville, Michael; Singovsky, Alexander; Cremaldi, Lucien Marcus; Godang, Romulus; Kroeger, Rob; Perera, Lalith; Rahmat, Rahmat; Sanders, David A; Summers, Don; Bloom, Kenneth; Bose, Suvadeep; Butt, Jamila; Claes, Daniel R; Dominguez, Aaron; Eads, Michael; Keller, Jason; Kelly, Tony; Kravchenko, Ilya; Lazo-Flores, Jose; Malbouisson, Helena; Malik, Sudhir; Snow, Gregory R; Baur, Ulrich; Godshalk, Andrew; Iashvili, Ia; Jain, Supriya; Kharchilava, Avto; Kumar, Ashish; Shipkowski, Simon Peter; Smith, Kenneth; Alverson, George; Barberis, Emanuela; Baumgartel, Darin; Boeriu, Oana; Chasco, Matthew; Reucroft, Steve; Swain, John; Trocino, Daniele; Wood, Darien; Zhang, Jinzhong; Anastassov, Anton; Kubik, Andrew; Odell, Nathaniel; Ofierzynski, Radoslaw Adrian; Pollack, Brian; Pozdnyakov, Andrey; Schmitt, Michael Henry; Stoynev, Stoyan; Velasco, Mayda; Won, Steven; Antonelli, Louis; Berry, Douglas; Hildreth, Michael; Jessop, Colin; Karmgard, Daniel John; Kolb, Jeff; Kolberg, Ted; Lannon, Kevin; Luo, Wuming; Lynch, Sean; Marinelli, Nancy; Morse, David Michael; Pearson, Tessa; Ruchti, Randy; Slaunwhite, Jason; Valls, Nil; Wayne, Mitchell; Ziegler, Jill; Bylsma, Ben; Durkin, Lloyd Stanley; Gu, Jianhui; Hill, Christopher; Killewald, Phillip; Kotov, Khristian; Ling, Ta-Yung; Rodenburg, Marissa; Williams, Grayson; Adam, Nadia; Berry, Edmund; Elmer, Peter; Gerbaudo, Davide; Halyo, Valerie; Hebda, Philip; Hunt, Adam; Jones, John; Laird, Edward; Lopes Pegna, David; Marlow, Daniel; Medvedeva, Tatiana; Mooney, Michael; Olsen, James; Piroué, Pierre; Quan, Xiaohang; Saka, Halil; Stickland, David; Tully, Christopher; Werner, Jeremy Scott; Zuranski, Andrzej; Acosta, Jhon Gabriel; Huang, Xing Tao; Lopez, Angel; Mendez, Hector; Oliveros, Sandra; Ramirez Vargas, Juan Eduardo; Zatserklyaniy, Andriy; Alagoz, Enver; Barnes, Virgil E; Bolla, Gino; Borrello, Laura; Bortoletto, Daniela; Everett, Adam; Garfinkel, Arthur F; Gutay, Laszlo; Hu, Zhen; Jones, Matthew; Koybasi, Ozhan; Kress, Matthew; Laasanen, Alvin T; Leonardo, Nuno; Liu, Chang; Maroussov, Vassili; Merkel, Petra; Miller, David Harry; Neumeister, Norbert; Shipsey, Ian; Silvers, David; Svyatkovskiy, Alexey; Yoo, Hwi Dong; Zablocki, Jakub; Zheng, Yu; Jindal, Pratima; Parashar, Neeti; Boulahouache, Chaouki; Cuplov, Vesna; Ecklund, Karl Matthew; Geurts, Frank JM; Padley, Brian Paul; Redjimi, Radia; Roberts, Jay; Zabel, James; Betchart, Burton; Bodek, Arie; Chung, Yeon Sei; Covarelli, Roberto; de Barbaro, Pawel; Demina, Regina; Eshaq, Yossof; Flacher, Henning; Garcia-Bellido, Aran; Goldenzweig, Pablo; Gotra, Yury; Han, Jiyeon; Harel, Amnon; Miner, Daniel Carl; Orbaker, Douglas; Petrillo, Gianluca; Vishnevskiy, Dmitry; Zielinski, Marek; Bhatti, Anwar; Ciesielski, Robert; Demortier, Luc; Goulianos, Konstantin; Lungu, Gheorghe; Malik, Sarah; Mesropian, Christina; Yan, Ming; Atramentov, Oleksiy; Barker, Anthony; Duggan, Daniel; Gershtein, Yuri; Gray, Richard; Halkiadakis, Eva; Hidas, Dean; Hits, Dmitry; Lath, Amitabh; Panwalkar, Shruti; Patel, Rishi; Richards, Alan; Rose, Keith; Schnetzer, Steve; Somalwar, Sunil; Stone, Robert; Thomas, Scott; Cerizza, Giordano; Hollingsworth, Matthew; Spanier, Stefan; Yang, Zong-Chang; York, Andrew; Eusebi, Ricardo; Gilmore, Jason; Gurrola, Alfredo; Kamon, Teruki; Khotilovich, Vadim; Montalvo, Roy; Osipenkov, Ilya; Pakhotin, Yuriy; Pivarski, James; Safonov, Alexei; Sengupta, Sinjini; Tatarinov, Aysen; Toback, David; Weinberger, Michael; Akchurin, Nural; Bardak, Cemile; Damgov, Jordan; Jeong, Chiyoung; Kovitanggoon, Kittikul; Lee, Sung Won; Mane, Poonam; Roh, Youn; Sill, Alan; Volobouev, Igor; Wigmans, Richard; Yazgan, Efe; Appelt, Eric; Brownson, Eric; Engh, Daniel; Florez, Carlos; Gabella, William; Issah, Michael; Johns, Willard; Kurt, Pelin; Maguire, Charles; Melo, Andrew; Sheldon, Paul; Snook, Benjamin; Tuo, Shengquan; Velkovska, Julia; Arenton, Michael Wayne; Balazs, Michael; Boutle, Sarah; Cox, Bradley; Francis, Brian; Hirosky, Robert; Ledovskoy, Alexander; Lin, Chuanzhe; Neu, Christopher; Yohay, Rachel; Gollapinni, Sowjanya; Harr, Robert; Karchin, Paul Edmund; Lamichhane, Pramod; Mattson, Mark; Milstène, Caroline; Sakharov, Alexandre; Anderson, Michael; Bachtis, Michail; Bellinger, James Nugent; Carlsmith, Duncan; Dasu, Sridhara; Efron, Jonathan; Flood, Kevin; Gray, Lindsey; Grogg, Kira Suzanne; Grothe, Monika; Hall-Wilton, Richard; Herndon, Matthew; Klabbers, Pamela; Klukas, Jeffrey; Lanaro, Armando; Lazaridis, Christos; Leonard, Jessica; Loveless, Richard; Mohapatra, Ajit; Palmonari, Francesco; Reeder, Don; Ross, Ian; Savin, Alexander; Smith, Wesley H; Swanson, Joshua; Weinberg, Marc
2011-01-01
A first measurement of the polarization of W bosons with large transverse momenta in pp collisions is presented. The measurement is based on 36 inverse picobarns of data recorded at sqrt(s) = 7 TeV by the CMS detector at the LHC. The left-handed, right-handed and longitudinal polarization fractions (f_L, f_R, f_0) of W bosons with transverse momenta larger than 50 GeV are determined using decays to both electrons and muons. The muon final state yields the most precise measurement, (f_L - f_R) = 0.240 ± 0.036 (stat.) ± 0.031 (syst.) and f_0 = 0.183 ± 0.087 (stat.) ± 0.123 (syst.) for negatively charged W bosons, and (f_L - f_R) = 0.310 ± 0.036 (stat.) ± 0.017 (syst.) and f_0 = 0.171 ± 0.085 (stat.) ± 0.099 (syst.) for positively charged W bosons. This establishes, for the first time, that W bosons produced in pp collisions with large transverse momenta are predominantly left-handed, as expected in the standard model.
Longitudinal Lelectroproduction of Charged Pions on Hydrogen, Deuterium, and Helium 3
Energy Technology Data Exchange (ETDEWEB)
Gaskell, David [Oregon State Univ., Corvallis, OR (United States)
2001-03-22
Conventional pictures of nuclear interactions, in which the pion mediates the long/medium range part of the nuclear force, predict an enhancement of the virtual pion cloud in nuclei relative to that in the free nucleon. Jefferson Lab Experiment E91003 measured charged pion electroproduction from Hydrogen, Deuterium, and Helium-3. The longitudinal cross section, which in the limit of pole dominance can be viewed as the quasifree knockout of a virtual pion, was extracted via a Rosenbluth separation. The longitudinal cross sections from Deuterium and Helium-3 were compared to Hydrogen to look for signatures of the nuclear pions.
Measurement of the pion form factor at higher energies
Energy Technology Data Exchange (ETDEWEB)
Mack, D.J. [CEBAF, Newport News, VA (United States)
1994-04-01
One of the strongest arguments for increasing the nominal CEBAF beam energy to equal or exceed 6 GeV is that one would be able to make quality high Q{sup 2} measurements of the charged pion form factor.
Muon identification and pion rejection in the 4th concept
Indian Academy of Sciences (India)
The ATLAS detector at the LHC has avoided this limit with air-core toroids both around the cylindrical detector providing a largely azimuthal field, and separate toroids to cover the end cap regions of the detector. 2. Two essential features. Momentum resolution for background pion rejection. On the 4th concept we also.
Information on pion-nucleus optical potentials from elastic scattering
International Nuclear Information System (INIS)
Friedman, E.
1983-02-01
Data on the elastic scattering of pions by nuclei between 20 and 230 MeV is analyzed in an almost model-independent fashion. The real part of the potential, which is described by a bias-free Fourier-Bessel series, is found to have the typical Kisslinger or Laplacian-like shape between 30 and 80 MeV
Dynamical pions and kaons in the glueball condensate vacuum
Energy Technology Data Exchange (ETDEWEB)
Hansson, T.H.; Klabuar, D.; Zahed, I.
1987-07-01
The model for pions as collective modes in the glueball condensate vacuum is extended to incorporate time-independent fields and massive quarks. The quark mass dependence of
Muon identification and pion rejection in the 4th concept
Indian Academy of Sciences (India)
The dual-solenoid magnetic field allows the reconstruction and precision momentum measurement of muons down to a few GeV (just the energy loss in the 10-int calorimeter and the coil) and the dual-readout calorimeter provides a new, unique and powerful separation of muons from pions. We use test beam data for the ...
Massive pions, anomalies and baryons in holographic QCD
Energy Technology Data Exchange (ETDEWEB)
Domenech, O. [Departament de Fisica and IFAE, Universitat Autonoma de Barcelona, 08193 Bellaterra, Barcelona (Spain); Panico, G., E-mail: panico@phys.ethz.c [Institute for Theoretical Physics, ETH Zurich, 8093 Zurich (Switzerland); Wulzer, A. [Institut de Theorie des Phenomenes Physiques, EPFL, CH-1015 Lausanne (Switzerland)
2011-03-01
We consider a holographic model of QCD, obtained by a very simple modification of the original construction, which describes at the same time the pion mass, the QCD anomalies and the baryons as topological solitons. We study in detail its phenomenological implications in both the mesonic and baryonic sectors and compare with the observations.
On the QCD effective action for pions and vector mesons
International Nuclear Information System (INIS)
Golterman, M.F.L.; Hari Dass, N.D.
1985-01-01
The effective action for pions and ρ, A 1 and ω vector mesons is discussed with the generating functional for QCD as a starting point and including the anomalous terms that orginate from the axial anomaly. The effective action is coupled to the weak-electromagnetic sector of the standard model and its experimental consequences are discussed. (orig.)
Anomalous electrodynamics of neutral pion matter in strong magnetic fields
Energy Technology Data Exchange (ETDEWEB)
Brauner, Tomáš [Department of Mathematics and Natural Sciences, University of Stavanger,N-4036 Stavanger (Norway); Kadam, Saurabh V. [Indian Institute of Science Education and Research (IISER),Pune 411008 (India)
2017-03-03
The ground state of quantum chromodynamics in sufficiently strong external magnetic fields and at moderate baryon chemical potential is a chiral soliton lattice (CSL) of neutral pions https://arxiv.org/abs/1609.05213. We investigate the interplay between the CSL structure and dynamical electromagnetic fields. Our main result is that in presence of the CSL background, the two physical photon polarizations and the neutral pion mix, giving rise to two gapped excitations and one gapless mode with a nonrelativistic dispersion relation. The nature of this mode depends on the direction of its propagation, interpolating between a circularly polarized electromagnetic wave https://www.doi.org/10.1103/PhysRevD.93.085036 and a neutral pion surface wave, which in turn arises from the spontaneously broken translation invariance. Quite remarkably, there is a neutral-pion-like mode that remains gapped even in the chiral limit, in seeming contradiction to the Goldstone theorem. Finally, we have a first look at the effect of thermal fluctuations of the CSL, showing that even the soft nonrelativistic excitation does not lead to the Landau-Peierls instability. However, it leads to an anomalous contribution to pressure that scales with temperature and magnetic field as T{sup 5/2}(B/f{sub π}){sup 3/2}.
Subthreshold Production of Neutral Pions in Heavy Ion Collisions
2002-01-01
The pion production below the threshold at 290 MeV/u (corresponding to the minimum beam velocity at which pions can be produced in nucleon-nucleon collisions) is sensitive to coherent effects in the momentum distribution of the nucleons in the internuclear collision region. Such collective or coherent effects would manifest themselves in an enhancement of the observed cross section with respect to a prediction on the basis of model momentum distributions, e.g. from the Fermi gas model. \\\\ \\\\ With neutral pions such experiments can be extended to rather low energies and rather small cross sections (in the sub-@mb range) due to the fact that the @p|0's leave the composite nuclear system undisturbed by the Coulomb forces and that their decay $\\gamma$ rays can be detected with high efficiency also at very low pion momentum. In our experiments using |1|2C~ions of 60, 74 and 84~MeV/u and |1|80 of 84~MeV/u we were able to clearly sep from background from different sources. The large efficiency of the annular lead gl...
Pion linac as an energy-tagged ν source
Directory of Open Access Journals (Sweden)
T. Goldman
2008-12-01
Full Text Available The energy spectrum and flux of neutrinos from a linear pion accelerator are calculated analytically under the assumption of a uniform accelerating gradient. The energy of a neutrino from this source reacting in a detector can be determined from timing and event position information.
Critique of a pion exchange model for interquark forces
International Nuclear Information System (INIS)
Isgur, N.
1999-01-01
The author describes four serious defects of a widely discuss pion exchange model for interquark forces: it doesn't solve the ''spin-orbit problem'' as advertised, it fails to describe the internal structure of baryon resonances, it leads to disastrous conclusions when extended to mesons, and it is not reasonably connected to the physics of heavy-light systems
Utilization of pion production accelerators in biomedical applications
International Nuclear Information System (INIS)
Rosen, L.
1979-01-01
A discussion is presented of biomedical applications of pion-producing accelerators in a number of areas, but with emphasis on pion therapy for treatment of solid, non-metastasized malignancies. The problem of cancer management is described from the standpoint of the physicist, magnitude of the problem, and its social and economic impact. Barriers to successful treatment are identified, mainly with regard to radiation therapy. The properties and characteristics of π mesons, first postulated on purely theoretical grounds by H. Yukawa are described. It is shown how they can be used to treat human cancer and why they appear to have dramatic advantages over conventional forms of radiation by virtue of the fact that they permit localization of energy deposition, preferentially, in the tumor volume. The Clinton P. Anderson Meson Physics Facility (LAMPF), and its operating characteristics, are briefly described, with emphasis on the biomedical channel. The design of a relatively inexpensive accelerator specifically for pion therapy is described as is also the status of clinical trials using the existing Clinton P. Anderson Meson Physics Facility. The advantages of proton over electron accelerator for the production of high quality, high intensity negative pion beams suitable for radiation therapy of malignancies is also addressed. Other current, medically related applications of LAMPF technology are also discussed
Renormalization of NN Interaction with Relativistic Chiral Two Pion Exchange
Energy Technology Data Exchange (ETDEWEB)
Higa, R; Valderrama, M Pavon; Arriola, E Ruiz
2007-06-14
The renormalization of the NN interaction with the Chiral Two Pion Exchange Potential computed using relativistic baryon chiral perturbation theory is considered. The short distance singularity reduces the number of counter-terms to about a half as those in the heavy-baryon expansion. Phase shifts and deuteron properties are evaluated and a general overall agreement is observed.
Neutral pion photoproduction on the proton at threshold
International Nuclear Information System (INIS)
Mazzucato, Eddy
1987-01-01
A precise determination of the neutral pion photoproduction amplitude on the proton at threshold has been obtained from differential cross-section measurements in the energy region close to threshold (145-173 MeV). The experiment was carried out at the Saclay Linac by using a monochromatic photon beam obtained by in-flight positron annihilation. The photon tagging system allowed a precise energy determination of the incoming beam with a resolution of about 1 MeV. The signature of a good event consisted in the observation of the neutral pion decay gammas in lead glass Cerenkov counters, in coincidence with the recoil proton detected in an active target made of plastic scintillators. The good energy resolution achieved on the energy of the recoil protons provided a precise determination of the differential cross-section. The analysis of the data in terms of multipoles gives a value for the threshold amplitude which is much smaller than the existing value extracted from higher energy experiments performed with untagged photon beams. The total cross-section in the high energy region is, however, in fairly good agreement with old measurements. The experimental value of the electric dipole agrees with several calculations based on dispersion relations. Yet, our measurement cannot be reproduced by the low-energy theorems extrapolated to the physical pion mass. This significant discrepancy exhibits clearly the importance of dispersive contributions in the case of neutral pion photoproduction at threshold. (author) [fr
Delta: the first pion nucleon resonance - its discovery and applications
International Nuclear Information System (INIS)
Nagle, D.E.
1984-07-01
It is attempted to recapture some of the fun and excitement of the pion-scattering work that led to the discovery of what is now called the delta particle. How significant this discovery was became apparent only gradually. That the delta is alive today and thriving at Los Alamos (as well as other places) is described
Muon identification and pion rejection in the 4th concept
Indian Academy of Sciences (India)
Abstract. We describe a completely new way to reconstruct and identify muons with high efficiency and very high pion rejection in the 4th concept detector. The dual-solenoid magnetic field allows the reconstruction and precision momentum measurement of muons down to a few GeV (just the energy loss in the 10-λint ...
Transverse target single-spin asymmetry in inclusive electroproduction of charged pions and kaons
Energy Technology Data Exchange (ETDEWEB)
Airapetian, A. [Giessen Univ. (Germany). 2. Physikalisches Inst.; Michigan Univ., Ann Arbor, MI (United States). Randall Laboratory of Physics; Akopov, N. [Yerevan Physics Institute (Argentina); Akopov, Z. [DESY Hamburg (Germany)] [and others; Collaboration: HERMES Collaboration
2013-10-15
Single-spin asymmetries were investigated in inclusive electroproduction of charged pions and kaons from transversely polarized protons at the HERMES experiment. The asymmetries were studied as a function of the azimuthal angle {psi} about the beam direction between the target-spin direction and the hadron production plane, the transverse hadron momentum P{sub T} relative to the direction of the incident beam, and the Feynman variable x{sub F}. The sin {psi} amplitudes are positive for {pi}{sup +} and K{sup +}, slightly negative for {pi}{sup -} consistent with zero for K{sup -}, with particular P{sub T} but weak x{sub F} dependences. Especially large asymmetries are observed for two small subsamples of events, where also the scattered electron was recorded by the spectrometer.
Analyses of pion-40Ca elastic scattering data using the Klein–Gordon equation
International Nuclear Information System (INIS)
Shehadeh, Z.F.
2009-01-01
The elastic scattering data for incident pion energies of 130, 163.3, 180, and 230 MeV on 40 Ca have been analyzed using the full Klein–Gordon equation (KGE), as opposed to its approximate form which renders it to the format of a Schroedinger equation with an energy-dependent potential (RSE). Calculated angular distributions, using KGE and RSE, for all four cases are nearly the same up to about 70° but differ significantly at larger angles. To fit the large-angle data of 163.3 MeV, the nature of the old potential determined by using RSE needs to be revised. The new potentials in four cases are presented and they are compatible with those determined from the inverse scattering theory at a fixed energy in the surface region. (author)
Transverse target single-spin asymmetry in inclusive electroproduction of charged pions and kaons
Energy Technology Data Exchange (ETDEWEB)
Airapetian, A. [II. Physikalisches Institut, Justus-Liebig-Universität Gießen, 35392 Gießen (Germany); Randall Laboratory of Physics, University of Michigan, Ann Arbor, MI 48109-1040 (United States); Akopov, N. [Yerevan Physics Institute, 375036 Yerevan (Armenia); Akopov, Z. [DESY, 22603 Hamburg (Germany); Aschenauer, E.C. [DESY, 15738 Zeuthen (Germany); Augustyniak, W. [National Centre for Nuclear Research, 00-689 Warsaw (Poland); Avakian, R.; Avetissian, A. [Yerevan Physics Institute, 375036 Yerevan (Armenia); Avetisyan, E. [DESY, 22603 Hamburg (Germany); Belostotski, S. [K.P. Konstantinov Petersburg Nuclear Physics Institute, Gatchina, 188300 Leningrad Region (Russian Federation); Bianchi, N. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, 00044 Frascati (Italy); Blok, H.P. [National Institute for Subatomic Physics (Nikhef), 1009 DB Amsterdam (Netherlands); Department of Physics and Astronomy, VU University, 1081 HV Amsterdam (Netherlands); Borissov, A. [DESY, 22603 Hamburg (Germany); Bowles, J. [SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Bryzgalov, V. [Institute for High Energy Physics, Protvino, 142281 Moscow Region (Russian Federation); Burns, J. [SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Capiluppi, M. [Istituto Nazionale di Fisica Nucleare, Sezione di Ferrara and Dipartimento di Fisica e Scienze della Terra, Università di Ferrara, 44122 Ferrara (Italy); Capitani, G.P. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, 00044 Frascati (Italy); Cisbani, E. [Istituto Nazionale di Fisica Nucleare, Sezione di Roma, Gruppo Collegato Sanità and Istituto Superiore di Sanità, 00161 Roma (Italy); and others
2014-01-20
Single-spin asymmetries were investigated in inclusive electroproduction of charged pions and kaons from transversely polarized protons at the HERMES experiment. The asymmetries were studied as a function of the azimuthal angle ψ about the beam direction between the target-spin direction and the hadron production plane, the transverse hadron momentum P{sub T} relative to the direction of the incident beam, and the Feynman variable x{sub F}. The sin ψ amplitudes are positive for π{sup +} and K{sup +}, slightly negative for π{sup −} and consistent with zero for K{sup −}, with particular P{sub T} but weak x{sub F} dependences. Especially large asymmetries are observed for two small subsamples of events, where also the scattered electron was recorded by the spectrometer.
Separable-potential model for the pion--nucleon interaction
International Nuclear Information System (INIS)
Nutt, W.T.
1976-01-01
A separable potential which fits the low and intermediate π-N scattering is proposed which is more convenient for application than those separable models which use Regge parameterizations of the very high energy phase shifts. The form factors for this model are equal to zero for momenta q greater than 1 GeV/c, and are expected to provide more reasonable off-shell behavior than the form factors obtained from those models based on the Regge extrapolation
LUCACI TIMOCE, A.
2012-01-01
We present a study of the showers initiated by low momentum (p 10 GeV) electrons, pions and protons in the highly granular CALICE scintillator-tungsten HCAL. The data were taken at the CERN PS in September-October 2010. The analysis includes energy resolution measurements for each particle type and studies of the longitudinal shower development. The results are compared with several GEANT4 models.
Lucaci-Timoce, A
2013-01-01
We present a study of the showers initiated by high momentum (10 ≤ pbeam ≤ 100 GeV) electrons, pions and protons in the highly granular CALICE analogue scintillator-tungsten hadronic calorimeter. The data were taken at the CERN SPS in 2011. The analysis includes measurements of the calorimeter response to each particle type and studies of the longitudinal and radial shower development. The results are compared to several GEANT4 simulation models.
AUTHOR|(CDS)2073690
2015-01-01
We present a study of showers initiated by 1–100 GeV positrons, pions, kaons, and protons in the highly granular CALICE analogue scintillator-tungsten hadronic calorimeter. The data were taken at the CERN PS and SPS. The analysis includes measurements of the calorimeter response to each particle type and studies of the longitudinal and radial shower development. The results are compared to several Geant4 simulation models.
Cross sections and average angular momenta in the fusion of 28Si+94,100Mo and 58,64Ni+64Ni
International Nuclear Information System (INIS)
Ackermann, D.; Beghini, S.; Montagnoli, G.; Mueller, L.; Segato, G.F.; Soramel, F.; Signorini, C.
1996-01-01
Fusion cross sections and mean angular momenta have been measured for the four systems 28 Si+ 94,100 Mo and 58,64 Ni+ 64 Ni and can be explained in the framework of the coupled-channel (CC) approach. In particular the influence of 2n-transfer channels with positive Q-values shows up. The direct relation between excitation function and angular momenta has been verified. (orig.)
Exclusive Photoproduction of Charged Pions in Hydrogen and Deuterium from 1 to 6 GeV
Energy Technology Data Exchange (ETDEWEB)
Zhu, Lingyan [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
2004-02-01
The study of the transition region in the description of exclusive processes and hadron structure, from the nucleon-meson degrees of freedom in meson-exchange models at low energy to the quark-gluon degrees of freedom in pQCD at high energy, is essential for us to understand the strong interaction. The differential cross section measurements for exclusive reactions at fixed center-of-mass angles enable us to investigate the constituent counting rule, which explicitly connects the quark-gluon degrees of freedom to the energy dependence of differential cross sections. JLab Experiment E94-104 was carried out in Hall A with two high resolution spectrometers. It included the coincidence cross section measurement for the γn --> π^{-}[p] process with a deuterium target and the singles measurement for the γp --> π^{+}[n] process with a hydrogen target. The untagged real photons were generated by the electron beam impinging on a copper radiator. The photon energies ranged from 1.1 to 5.5 GeV, corresponding to the center-of-mass energies from 1.7 to 3.4 GeV. The pion center-of-mass angles were fixed at 50 deg, 70 deg, 90 deg, and also 100 deg, 110 deg at a few energies. The JLab E94-104 data presented in this thesis contain four interesting features. The data exhibit a global scaling behavior for both π^{-} and π^{+} photoproduction at high energies and high transverse momenta, consistent with the constituent counting rule and the existing π^{+} photoproduction data. This implies that the quark-gluon degrees of freedom start to play a role at this energy scale. The data suggests possible substructure of the scaling behavior, which might be oscillations around the scaling value. There are several possible mechanisms that can cause oscillations, for example the one associated with the generalized constituent counting rule involving quark orbital angular momentum. The data show an enhancement in the scaled cross section at center
Tavakoli, Mohammad Bagher; Mohammadi, Mohammad Mehdi; Reiazi, Reza; Jabbari, Keyvan
2015-01-01
Geant4 is an open source simulation toolkit based on C++, which its advantages progressively lead to applications in research domains especially modeling the biological effects of ionizing radiation at the sub-cellular scale. However, it was shown that Geant4 does not give a reasonable result in the prediction of antiproton dose especially in Bragg peak. One of the reasons could be lack of reliable physic model to predict the final states of annihilation products like pions. Considering the fact that most of the antiproton deposited dose is resulted from high-LET nuclear fragments following pion interaction in surrounding nucleons, we reproduced depth dose curves of most probable energy range of pions and neutron particle using Geant4. We consider this work one of the steps to understand the origin of the error and finally verification of Geant4 for antiproton tracking. Geant4 toolkit version 9.4.6.p01 and Fluka version 2006.3 were used to reproduce the depth dose curves of 220 MeV pions (both negative and positive) and 70 MeV neutrons. The geometry applied in the simulations consist a 20 × 20 × 20 cm(3) water tank, similar to that used in CERN for antiproton relative dose measurements. Different physic lists including Quark-Gluon String Precompound (QGSP)_Binary Cascade (BIC)_HP, the recommended setting for hadron therapy, were used. In the case of pions, Geant4 resulted in at least 5% dose discrepancy between different physic lists at depth close to the entrance point. Even up to 15% discrepancy was found in some cases like QBBC compared to QGSP_BIC_HP. A significant difference was observed in dose profiles of different Geant4 physic list at small depths for a beam of pions. In the case of neutrons, large dose discrepancy was observed when LHEP or LHEP_EMV lists were applied. The magnitude of this dose discrepancy could be even 50% greater than the dose calculated by LHEP (or LHEP_EMV) at larger depths. We found that effect different Geant4 physic list in
Spectrum and Charge Ratio of Vertical Cosmic Ray Muons up to Momenta of 2.5 TeV/c
Schmelling, M; Grupen, C; Luitz, S; Maciuc, F; Mailov, A; Müller, A -S; Sander, H -G; Schmeling, S; Tcaciuc, R; Wachsmuth, H; Zuber, K
2013-01-01
The ALEPH detector at LEP has been used to measure the momentum spectrum and charge ratio of vertical cosmic ray muons underground. The sea-level cosmic ray muon spectrum for momenta up to 2.5 TeV/c has been obtained by correcting for the overburden of 320 meter water equivalent (mwe). The results are compared with Monte Carlo models for air shower development in the atmosphere. From the analysis of the spectrum the total flux and the spectral index of the cosmic ray primaries is inferred. The charge ratio suggests a dominantly light composition of cosmic ray primaries with energies up to 10^15 eV.
Isomeric yield ratios and mean angular momenta of photofission fragments of 235U, 237Np and 239Pu
Directory of Open Access Journals (Sweden)
I.M. Vyshnevskyi
2015-04-01
Full Text Available Isomeric yield ratios for the fragments of photofission of 235U, 237Np and 239Pu by bremsstrahlung with end-point energy of 18 MeV are measured. New data for isomeric yield ratios of the fragments 84Se, 90Br, 131Te, 132Sb, 132I, 133Te, 134I, 135Xe are determined. The contributions to the isomeric yield ratios from β-decay of the nuclei of parent isobaric chains were removed. Mean angular momenta of studied nuclei are estimated within the framework of an extended Huizenga-Vandenbosh statistical model with using EMPIRE 3.2 code.
Polarization transfer in weak pion production off the nucleon
Graczyk, Krzysztof M.; Kowal, Beata E.
2018-01-01
Polarization transfer (PT) observables in the single pion production induced by the charged current interaction of the neutrino with the nucleon are examined. The polarization components of the final nucleon and the charged lepton are calculated within two models for the pion production. The predictions are made for neutrino energy of the order of 1 GeV as well as for the T2K energy distribution. It is demonstrated that the PT observables, the degree of polarization and the polarization components of outgoing fermions, are sensitive to assumptions about the nonresonant background model. In particular it is shown that the normal components of the polarization of the outgoing nucleon and the lepton are determined by the interference between the resonant (RES) and nonresonant (NB) amplitudes. Moreover, the sign of the normal component of the polarization of the charged lepton is fixed by the relative sign between the RES and the NB amplitudes.
Experiments on the nuclear interactions of pions and electrons
International Nuclear Information System (INIS)
Minehart, R.C.; Ziock, K.O.H.
1990-06-01
This paper discusses: π + + d → 2p; Pion Absorption in 3 He; Pion Absorption in 4 He; Evidence for narrow structure in the analyzing power of the 3 He (rvec p, d)X reaction; Coherent η-Meson Production in the Reaction π- + 3 He → η + t; Search for heavy neutrinos; The search for fractionally charged particles; Search for the rare decay, μ + → e + + γ; A Precise Measurement of the π + → π 0 e + ν Decay Rate; Transverse and Longitudinal Response Functions for Several Nuclei near Q 2 = 1 (GeV/c) 2 ; The Q 2 -dependence of the 4 He (e, e'p) coincidence cross section at the quasielastic peak; The Response Function R LT in the reaction 16 O(e, e' p); and Absorption of anti-protons in heavy nuclei
Effective Lagrangian Approach to pion photoproduction from the nucleon
International Nuclear Information System (INIS)
Fernandez-Ramirez, C.; Moya de Guerra, E.; Udias, J.M.
2006-01-01
We present a pion photoproduction model on the free nucleon based on an Effective Lagrangian Approach (ELA) which includes the nucleon resonances (Δ(1232), N(1440), N(1520), N(1535), Δ(1620), N(1650), and Δ(1700)), in addition to Born and vector meson exchange terms. The model incorporates a new theoretical treatment of spin-3/2 resonances, first introduced by Pascalutsa, avoiding pathologies present in previous models. Other main features of the model are chiral symmetry, gauge invariance, and crossing symmetry. We use the model combined with modern optimization techniques to assess the parameters of the nucleon resonances on the basis of world data on electromagnetic multipoles. We present results for electromagnetic multipoles, differential cross-sections, asymmetries, and total cross-sections for all one pion photoproduction processes on free nucleons. We find overall agreement with data from threshold up to 1 GeV in laboratory frame
Pion Electroproduction form Helium 3, Deuterium, and Hydrogen
Energy Technology Data Exchange (ETDEWEB)
Avery, Stephen Milton [Hampton Univ., Hampton, VA (United States)
2002-05-01
A series of measurements for pion electroproduction from helium-3, deuterium, and hydrogen were completed at the Thomas Jefferson National Accelerator Facility by the NucPi Collaboration. E91003 began taking data in February 1998 and was completed in April 1998. The longitudinal and transverse parts of the differential cross section were extracted, by means of a Rosenbluth type separation, in the direction parallel to the virtual photon, at Q ^{2} = 0.4 GeV ^{2} , for W = 1.15 and W = 1.6 GeV. The mass dependence of the longitudinal cross section should provide insight into the surprising apparent absence of any significant cross section enhancement due to excess pions in the nuclear medium.
Pion form factor in QCD at intermediate momentum transfers
Braun, V. M.; Khodjamirian, A.; Maul, M.
2000-04-01
We present a quantitative analysis of the electromagnetic pion form factor in the light-cone sum rule approach, including radiative corrections and higher-twist effects. The comparison to the existing data favors the asymptotic profile of the pion distribution amplitude and allows us to estimate the deviation: [∫du/uφπ(u)]/[∫du/uφasπ(u)]=1.1+/-0.1 at the scale of 1 GeV. Special attention is paid to the precise definition and interplay of soft and hard contributions at intermediate momentum transfer, and to the matching of the sum rule to the perturbative QCD prediction. We observe a strong numerical cancellation between the soft (end-point) contribution and power-suppressed hard contributions of higher twist, so that the total nonperturbative correction to the usual PQCD result turns out to be of the order of 30% for Q2~1 GeV2.
Goldstone pion and other mesons using a scalar confining interaction
International Nuclear Information System (INIS)
Gross, F.; Milana, J.
1994-01-01
A covariant wave equation for q bar q interactions with an interaction kernel composed of the sum of constant vector and linear scalar confining interactions is solved for states with two quarks with identical mass. The model includes an NJL-like mechanism which links the dynamical breaking of chiral symmetry to the spontaneous generation of quark mass and the appearance of a low mass Goldstone pion. A novel feature of this approach is that it automatically explains the small mass of the pion even though the linear potential is a scalar interaction in Dirac space, and hence breaks chiral symmetry. Solutions for mesons composed of light quarks (π,ρ, and low lying excited states) and heavy quarks (ρ c , J/Ψ, and low lying excited states) are presented and discussed
Quark mass functions and pion structure in Minkowski space
Energy Technology Data Exchange (ETDEWEB)
Biernat, Elmer P. [CFTP, Institute Superior Tecnico; Gross, Franz L. [JLAB; Pena, Maria Teresa [CFTP, Institute Superior Tecnico; Stadler, Alfred [University of Evora
2014-03-01
We present a study of the dressed quark mass function and the pion structure in Minkowski space using the Covariant Spectator Theory (CST). The quark propagators are dressed with the same kernel that describes the interaction between different quarks. We use an interaction kernel in momentum space that is a relativistic generalization of the linear confining q-qbar potential and a constant potential shift that defines the energy scale. The confining interaction has a Lorentz scalar part that is not chirally invariant by itself but decouples from the equations in the chiral limit and therefore allows the Nambu--Jona-Lasinio (NJL) mechanism to work. We adjust the parameters of our quark mass function calculated in Minkowski-space to agree with LQCD data obtained in Euclidean space. Results of a calculation of the pion electromagnetic form factor in the relativistic impulse approximation using the same mass function are presented and compared with experimental data.
Measurement of Neutrino Induced, Charged Current, Charged Pion Production
Energy Technology Data Exchange (ETDEWEB)
Wilking, Michael Joseph [Univ. of Colorado, Boulder, CO (United States)
2009-05-01
Neutrinos are among the least understood particles in the standard model of particle physics. At neutrino energies in the 1 GeV range, neutrino properties are typically determined by observing the outgoing charged lepton produced in a charged current quasi-elastic interactions. The largest charged current background to these measurements comes from charged current pion production interactions, for which there is very little available data.
Quark condensate effects on charmonium-pion scattering
Indian Academy of Sciences (India)
F S NAVARRA and M NIELSEN. Instituto de Fısica, Universidade de S˜ao Paulo, C.P. 66318, 05389-970 S˜ao Paulo, Brazil .... terms on the theoretical side and taking the limit p1µ —0 in the residue of the pion pole, one obtains for the contribution of .... The solid line gives the total J ψπ dissociation cross-section. Finally, we ...
Coherent pion photoproduction from deuterium at intermediate energies
International Nuclear Information System (INIS)
Osland, P.; Rej, A.K.
1975-12-01
The coherent photoproduction of neutral pions on deuterons is studied at energies around the (3,3) resonance and discuss the effects of the Fermi motion, rescattering and kinematical approximations. The results are very dependent upon what kinematical approximations one adopts for the impulse approximation term, which dominates up to very large angles. Allowing for this uncertainty in the kinematics, our results are in good agreement with the most recent experimental data
The development of the clinical pion program at TRIUMF
International Nuclear Information System (INIS)
Goodman, G.B.; Dixon, P.; Flores, A.; Harrison, R.W.; Lam, G.K.Y.; Ludgate, C.M.
1985-01-01
The authors have been treating brain and pelvic cancers with pions at TRIUMF since May, 1982. Studies focussed on dose optimization strategies, evolution of techniques, assessment of normal tissue and tumour responses and patient accruals. This presentation illustrates innovations using MRI and PET scanning in brain tumours and endoscopic photography and biopsy for bowel cancer. Results are presented to December, 1984 for 32 glioblastoma multiforme and 35 incurable pelvic cancer using a spot-san mode. Growth delay and survival curves is presented
Pion form factor at intermediate momentum transfer in QCD
International Nuclear Information System (INIS)
Ioffe, B.L.; Smilga, A.V.
1982-01-01
A general method is proposed for the QCD based calculation of form factors at intermediate Q 2 and of the partial widths of the low-lying meson resonances. The basic idea is to use QCD sum rules for the vertex functions. With this method, the pion form factor at 0.5 2 2 is calculated. The results are in good agreement with experiment
Nuclear compression effects on pion production in nuclear collisions
International Nuclear Information System (INIS)
Sano, M.; Gyulassy, M.; Wakai, M.; Kitazoe, Y.
1985-01-01
We show that the method of analyzing the pion excitation function proposed by Stock et al. may determine only a part of the nuclear matter equation of state. With the addition of missing kinetic energy terms the implied high density nuclear equation of state would be much stiffer than expected from conventional theory. A stiff equation of state would also follow if shock dynamics with early chemical freeze out were valid. (orig.)
Determination of the pion-nucleon coupling constant
International Nuclear Information System (INIS)
Samaranayake, V.K.
1977-06-01
Forward dispersion relations are used to determine the pion-nucleon coupling constant and S-wave scattering lengths using a least squares fit with additional parameters introduced to take account of the uncertainties in the calculation of dispersion integrals. The values obtained are: f 2 = (78.0+- 2.1).10 -3 , a 1 -a 3 = (272.4+- 12.3).10 -3 , a 1 +2a 3 = (15.1+-10.4).10 -3
Quark and pion effective couplings from polarization effects
Energy Technology Data Exchange (ETDEWEB)
Braghin, Fabio L. [Federal University of Goias, Instituto de Fisica, Goiania, GO (Brazil)
2016-05-15
A flavor SU(2) effective model for pions and quarks is derived by considering polarization effects departing from the usual quark-quark effective interaction induced by dressed gluon exchange, i.e. a global color model for QCD. For that, the quark field is decomposed into a component that yields light mesons and the quark-antiquark condensate, being integrated out by means of the auxiliary field method, and another component which yields constituent quarks, which is basically a background quark field. Within a long-wavelength and weak quark field expansion (or large quark effective mass expansion) of a quark determinant, the leading terms are found up to the second order in a zero-order derivative expansion, by neglecting vector mesons that are considerably heavier than the pion. Pions are considered in the structureless limit and, besides the chiral invariant terms that reproduce previously derived expressions, symmetry breaking terms are also presented. The leading chiral quark-quark effective couplings are also found corresponding to a NJL and a vector-NJL couplings. All the resulting effective coupling constants and parameters are expressed in terms of the current and constituent quark masses and of the coupling g. (orig.)
Two-pion correlations in heavy ion collisions
International Nuclear Information System (INIS)
Zajc, W.A.
1982-08-01
An application of intensity interferometry to relativistic heavy ion collisions is reported. Specifically, the correlation between two like-charged pions is used to study the reactions Ar+KCl→2π/sup +-/+X and Ne+NaF→2π - +X. Source sizes are obtained that are consistent with a simple geometric interpretation. Lifetimes are less well determined but are indicative of a faster pion production process than predicted by Monte Carlo cascade calculations. There appears to be a substantial coherent component of the pion source, although measurement is complicated by the presence of final state interactions. Additionally, the generation of spectra of uncorrelated events is discussed. In particular, the influence of the correlation function on the background spectrum is analyzed, and a prescription for removal of this influence is given. A formulation to describe the statistical errors in the background is also presented. Finally, drawing from the available literature, a self-contained introduction to Bose-Einstein correlations and the Hanbury-Brown - Twiss effect is provided, with an emphasis on points of contact between classical and quantum mechanical descriptions
Pion transition form factor in k{sub T} factorization
Energy Technology Data Exchange (ETDEWEB)
Li, Hsiang-nan [Academica Sinica, Taipei, Taiwan (China). Inst. of Physics; Tsing-Hua Univ., Hsinchu, Taiwan (China). Dept. of Phyiscs; National Cheng-Kung Univ., Tainan, Taiwan (China). Dept. of Physics; National Cheng-Chi Univ, Taipei, Taiwan (China). Inst. of Applied Physics; Mishima, Satoshi [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2009-07-15
It has been pointed out that the recent BaBar data on the {pi}{gamma}{sup *} {yields} {gamma} transition form factor F{sub {pi}}{sub {gamma}}(Q{sup 2}) at low (high) momentum transfer squared Q{sup 2} indicate an asymptotic (flat) pion distribution amplitude. These seemingly contradictory observations can be reconciled in the k{sub T} factorization theorem: the increase of the measured Q{sup 2}FF{sub {pi}}{sub {gamma}}(Q{sup 2}) for Q{sup 2} > 10 GeV{sup 2} is explained by convoluting a k{sub T} dependent hard kernel with a flat pion distribution amplitude, k{sub T} being a parton transverse momentum. The low Q{sup 2} data are accommodated by including the resummation of {alpha}{sub s} ln{sup 2}x, x being a parton momentum fraction, which provides a stronger suppression at the endpoints of x. The next-to-leading-order correction to the pion transition form factor is found to be less than 20% in the considered range of Q{sup 2}. (orig.)
Two-pion correlations in heavy ion collisions
Energy Technology Data Exchange (ETDEWEB)
Zajc, W.A.
1982-08-01
An application of intensity interferometry to relativistic heavy ion collisions is reported. Specifically, the correlation between two like-charged pions is used to study the reactions Ar+KCl..-->..2..pi../sup +-/+X and Ne+NaF..-->..2..pi../sup -/+X. Source sizes are obtained that are consistent with a simple geometric interpretation. Lifetimes are less well determined but are indicative of a faster pion production process than predicted by Monte Carlo cascade calculations. There appears to be a substantial coherent component of the pion source, although measurement is complicated by the presence of final state interactions. Additionally, the generation of spectra of uncorrelated events is discussed. In particular, the influence of the correlation function on the background spectrum is analyzed, and a prescription for removal of this influence is given. A formulation to describe the statistical errors in the background is also presented. Finally, drawing from the available literature, a self-contained introduction to Bose-Einstein correlations and the Hanbury-Brown - Twiss effect is provided, with an emphasis on points of contact between classical and quantum mechanical descriptions.
Precision determination of the lifetime of the neutral pion
2002-01-01
The experiment aims at a determination of the lifetime of the neutral pion with an accuracy of 1\\%, as against at present 5\\% for the best measurement by the indirect, Primakoff method, and 18\\% by a direct measurement. \\\\\\\\2 gold foils with different separations are traversed by the extracted proton beam to the High Intensity Area. Positive particles of 160 GeV/c momentum from this target are transported by the H6 beam to the North Area. The electron component is separated from heavier particles by synchrotron losses in the bending magnets, and is further identified by a lead glass Cerenkov counter, in coincidence with scintillation counters (Fig. 1).\\\\\\\\ The electron flux from the double foil target depends on the distance between the foils, since for small separations the neutral pions will have to decay before electrons can be materialised by the decay $\\gamma$ rays.\\\\\\\\ The average momentum of neutral pions from a 400 GeV pN reaction, giving a 160 GeV/c electron, is about 250 GeV/c, and the corresponding...
Kinematic aspects of pion-nucleus elastic scattering
International Nuclear Information System (INIS)
Weiss, D.L.; Ernst, D.J.
1982-01-01
The inclusion of relativistic kinematics in the theory of elastic scattering of pions from nuclei is examined. The investigation is performed in the context of the first order impulse approximation which incorporates the following features: (1) Relative momentum are defined according to relativistic theories consistent with time reversal invariance. (2) The two-nucleon interaction is a new, multichannel, separable potential model consistent with the most recent data derived from a recent nonpotential model of Ernst and Johnson. (3) The recoil of the pion-nucleon interacting pair and its resultant nonlocality are included. (4) The Fermi integral is treated by an optimal factorization approximation. It is shown how a careful definition of an intrinsic target density leads to an unambiguous method for including the recoil of the target. The target recoil corrections are found to be large for elastic scattering from 4 He and not negligible for scattering from 12 C. Relativistic potential theory kinematics, kinematics which result from covariant reduction approaches, and kinematics which result from replacing masses by energies in nonrelativistic formulas are compared. The relativistic potential theory kinematics and covariant reduction kinematics are shown to produce different elastic scattering at all pion energies examined (T/sub π/<300 MeV). Simple extensions of nonrelativistic kinematics are found to be reasonable approximations to relativistic potential theory
Dressed Quark Mass Dependence of Pion and Kaon Form Factors
Energy Technology Data Exchange (ETDEWEB)
Ninomiya, Y.; Bentz, W.; Cloet, I. C.
2015-02-04
The structure of hadrons is described well by the Nambu-Jona-Lasinio (NJL) model, which is a chiral effective quark theory of QCD. In this work we explore the electromagnetic structure of the pion and kaon using the three-flavor NJL model in the proper-time regularization scheme, including effects of the pion cloud at the quark level. In the calculation there is only one free parameter, which we take as the dressed light quark (u and d) mass. In the regime where the dressed light quark mass is approximately 0.25 GeV we find that the calculated values of the kaon decay constant, current quark masses, and quark condensates are consistent with experiment- and QCD-based analyses. We also investigate the dressed light quark mass dependence of the pion and kaon electromagnetic form factors, where comparison with empirical data and QCD predictions also favors a dressed light quark mass near 0.25 GeV.
Pion structure function from leading neutron electroproduction and SU(2) flavor asymmetry
Energy Technology Data Exchange (ETDEWEB)
McKenney, Joshua R. [North Carolina State Univ., Raleigh, NC (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Univ. of North Carolina, Chapel Hill, NC (United States); Sato Gonzalez, Nobuo; Melnitchouk, Wally [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Ji, Chueng-Ryong [North Carolina State Univ., Raleigh, NC (United States)
2016-03-01
We examine the efficacy of pion exchange models to simultaneously describe leading neutron electroproduction at HERA and the $\\bar{d}-\\bar{u}$ flavor asymmetry in the proton. A detailed $\\chi^2$ analysis of the ZEUS and H1 cross sections, when combined with constraints on the pion flux from Drell-Yan data, allows regions of applicability of one-pion exchange to be delineated. The analysis disfavors several models of the pion flux used in the literature, and yields an improved extraction of the pion structure function and its uncertainties at parton momentum fractions in the pion of $4 \\times 10^{-4} \\lesssim x_\\pi \\lesssim 0.05$ at a scale of $Q^2$=10 GeV$^2$. Based on the fit results, we provide estimates for leading proton structure functions in upcoming tagged deep-inelastic scattering experiments at Jefferson Lab on the deuteron with forward protons.
Inclusive charged and neutral pion photoproduction at 20 GeV
International Nuclear Information System (INIS)
Rickman O'Dell, V.
1987-05-01
The inclusive charged and neutral pion distributions from the interactions of 20 GeV photons on protons have been measured. The assumptions and analysis done to obtain these distributions are described, and the pion distributions are found to agree with general predictions of the quark-parton model. The quark-quark fusion model and the recombination model were compared to the inclusive pion distributions assuming the photon could be approximated by a superposition of rho and omega vector meson states - an assumption prompted by the Vector Meson Dominance Model of photon structure. Quark models applied to the difference in the charged pion cross sections are examined. The inclusive charge structure of the photoproduced charged pions and that of electroproduced and hadroproduced charged pions were compared
Inclusive measurements of pion double charge exchange and inelastic scattering on 3He
International Nuclear Information System (INIS)
Yuly, M.E.
1993-06-01
A measurement was made at the Los Alamos Meson Physics Facility (LAMPF) of the doubly differential cross sections for three inclusive pion reactions on 3 He: π - double charge exchange (DCX), and π + and π - inelastic scattering. The cross sections for DCX were measured at incident energies of 120, 180, 210, and 240 MeV, and at angles of 25, 50, 80, 105, and 130 degrees, while inelastic scattering cross sections were measured at 120, 180, and 240 MeV and scattering angles of 50, 80, 105, and 130 degrees. The final pion energy spectrum was measured from 10 MeV up to the kinematic limit. In the Δ resonance region, where the isospin T = 3/2 channel dominates, the inelastic π - scattering should be almost entirely from the lone neutron in 3 He. The π + inelastic scattering was expected to have significant contributions from both single and double scattering, because the T = 3/2 channel favors π + -p scattering from the two protons in 3 He. The 3 He DCX spectra are similar to those observed for DCX in 4 He. The forward angle double peaks can be understood as a consequence of sequential single charge exchange (SSCX). Calculations using the SSCX model are in rough agreement with the measured shape of the 3 He DCX spectra. The doubly differential cross sections measured for the inelastic scattering reactions exhibit a strong enhancement near the kinematics for free π - -p scattering. The ratios of π + to π - scattering cross sections may indicate multiple scattering, as well as the agreement of the low outgoing energy part of the π + inelastic scattering spectra with the corresponding properly scaled DCX spectra. A distorted-wave impulse-approximation (DWIA) calculation of the quasielastic cross sections has been performed and a comparison made with the measured inelastic cross sections
Lansberg, Jean-Philippe
2015-01-01
The recent observations of prompt J/psi-pair production by CMS at the LHC and by D0 at the Tevatron reveal the presence of different production mechanisms in different kinematical regions. We find out that next-to-leading-order single-parton-scattering contributions at alpha_s^5 dominate the yield at large transverse momenta of the pair. Our analysis further emphasises the importance of double-parton-scatterings --which are expected to dominate the yield at large rapidity differences-- at large invariant masses of the pair in the CMS acceptance. In addition, we provide the first exact --gauge-invariant and infrared-safe-- evaluation of a class of leading-P_T next-to-next-to-leading-order contributions, which are dominant in the region of large sub-leading transverse momenta, precisely where the colour-octet contributions can be non-negligible. Finally, we discuss the contribution from decays of excited charmonium states within both single- and double-parton scatterings and suggest measurements to distinguish ...
Single pion and several pions production in π+p interactions at 1.6 GeV/c
International Nuclear Information System (INIS)
Jabiol, M.A.
1966-01-01
The production of ρ + , N 33 * , and η 0 was observed in π + p interactions at 1.6 GeV/c. In the reactions where one pion is created, the comparison between the experimental distribution of the ρ + and the N 33 * with the predictions of the peripheral model modified by absorption effects permits the conclusion that the contribution of this model is important, but that other effects such as interferences between ρ + and N 33 * are not negligible. In the reactions where several pions are created, the branching ratios of some decay modes of η0 are evaluated and the associated production of η 0 and N 33 * is observed. (author) [fr
Scattering of low-energy pions by p-shell nuclei
International Nuclear Information System (INIS)
Khankhasaev, M.Kh.
1987-01-01
Low-energy pion-carbon scattering (up to 50 MeV) is analysed in the framework of the unitary approach based on the method of evolution in the coupling constant. It is shown that at pion energy ∼ 50 MeV the differential cross section arises as a result of the strong interference between the pure potential scattering and absorption channels. In this energy region the scattering data are very sensitive to the dynamics of the pion-nucleus interaction
Azimuthal dependence of pion source radii in Pb + Au collisions at 158 A GeV
AUTHOR|(CDS)2073202; Andronic, A; Antonczyk, D; Appelshäuser, H; Belaga, V; Bielcikova, J; Braun-Munzinger, P; Busch, O; Cherlin, A; Damjanovic, S; Dietel, T; Dietrich, L; Drees, A; Dubitzky, W; Esumi, S I; Filimonov, K; Fomenko, K; Fraenkel, Zeev; Garabatos, C; Glässel, P; Hering, G; Holeczek, J; Kalisky, M; Kniege, S; Kushpil, V; Maas, A; Marin, A; Milosevic, J; Miskowiec, D; Ortega, R; Panebratsev, Yu A; Petchenova, O; Petracek, V; Ploskon, M; Radomski, S; Rak, J; Ravinovich, I; Rehak, P; Sako, H; Schmitz, W; Schuchmann, S; Schükraft, J; Sedykh, S; Shimansky, S; Soualah, R; Stachel, J; Sumbera, M; Tilsner, H; Tserruya, Itzhak; Tsiledakis, G; Wessels, J P; Wienold, T; Wurm, J P; Yurevich, S; Yurevich, V
2008-01-01
We present results of a two-pion correlation analysis performed with the Au+Pb collision data collected by the upgraded CERES experiment in the fall of 2000. The analysis was done in bins of the reaction centrality and the pion azimuthal emission angle with respect to the reaction plane. The pion source, deduced from the data, is slightly elongated in the direction perpendicular to the reaction plane, similarly as was observed at the AGS and at RHIC.
Pion absorption in nuclei: The (. pi. /sup + -/,p) reactions
Energy Technology Data Exchange (ETDEWEB)
Mishra, C.S.
1987-05-01
Reported here is the first experiment to measure the excitation of discrete final states following the (..pi../sup -/,p) reaction. The Energetic Pion Channel and Spectrometer (EPICS) at the Los Alamos National Laboratory and the High Resolution Pion Channel and Spectrometer (..pi..M1-SUSI) at the Swiss Institute for Nuclear Physics were used for this high resolution study of (..pi../sup + -/,p) reactions. An average energy resolution of 500 KeV and 700 KeV was achieved at EPICS and ..pi..M1-SUSI respectively. At EPICS these reactions were measured at T/sub ..pi../ = 120 MeV and theta/sub lab/ = 25/sup 0/ on /sup 24/Mg, /sup 27/Al, /sup 40/Ca and /sup 58/Ni; /sup 12/C(..pi../sup -/,p) was measured at T/sub ..pi../ = 145 MeV. At ..pi..M1-SUSI these reactions were measured at T/sub ..pi../ = 90 MeV and at theta/sub lab/ = 20/sup 0/ on /sup 23/Na and /sup 24/Mg. The measurement includes both the differential cross sections and continuum up to an excitation energy of 40 MeV. In /sup 23/Na, /sup 24/Mg, and /sup 27/Al there are peaks in the low excitation region. The shape of the continuum in an excitation energy range of 10 to 40 MeV was found to be independent of pion charge and target mass. The magnitude of proton yield from all the targets at T/sub ..pi../ = 120 MeV is more than twenty four times larger for ..pi../sup +/ than for ..pi../sup -/. Also, the cross sections for both reactions on /sup 24/Mg is slightly enhanced compared to other nuclei. At T/sub ..pi../ = 90 MeV the ratio of the proton yield for ..pi../sup +/ to ..pi../sup -/ absorption drops down to fourteen. This high ratio and its energy dependence supports the idea of a two nucleon pion absorption model. Pion absorption in the context of both the reaction mechanism and nuclear structure is discussed. 99 refs., 64 figs., 11 tabs.
International Nuclear Information System (INIS)
Minehart, R.C.; Ziock, K.O.H.
1981-01-01
Progress is reviewed in these research areas: π-d elastic scattering; π-elastic and quasi-free scattering from helium isotopes; pion charge exchange in 3 He; pion absorption in 3 He and 4 He; quasi-free pion scattering; π → μ + ν experiment; study of the π 0 → 2e decay; measurement of the π - - π 0 mass difference; design of a low energy pion spectrometer; π + d → p + p in the energy range 60 to 200 MeV
FFAG Beam Line for nuPIL - Neutrinos from PIon Beam Line
Energy Technology Data Exchange (ETDEWEB)
Lagrange, Jean-Baptiste [Fermilab; Pasternak, Jaroslaw [Rutherford; Bross, Alan [Fermilab; Liu, Ao [Fermilab; Appleby, Robert [Cockcroft Inst. Accel. Sci. Tech.; Tygier, Sam [Cockcroft Inst. Accel. Sci. Tech.
2016-06-01
The Long Baseline Neutrino Facilities (LBNF) program aims to deliver a neutrino beam for the Deep Underground Neutrino Experiment (DUNE). The current baseline for LBNF is a conventional magnetic horn and decay pipe system. Neutrinos from PIon beam Line (nuPIL) is a part of the optimization effort to optimize the LBNF. It consists of a pion beam line after the horn to clean the beam of high energy protons and wrong-sign pions before transporting them into a decay beam line, where instrumentation could be implemented. This paper focuses on the FFAG solution for this pion beam line. The resulting neutrino flux is also presented.
A phenomenological determination of the pion-nucleon scattering lengths from pionic hydrogen
Ericson, Torleif Eric Oskar; Wycech, S
2005-01-01
A model independent expression for the electromagnetic corrections to a phenomenological hadronic pion-nucleon scattering length, extracted from pionic hydrogen, is obtained. In a non-relativistic approach and using an extended charge distribution, these corrections are derived up to terms of order (alpha)**2 log(alpha) in the limit of a short-range hadronic interaction. We infer a charged pion-proton scattering length of 0.0870(5) in units of inverse pion mass, which gives for the charged pion-proton-neutron coupling, through the GMO relation, a value of 14.04(17).
Coupled channel theory of pion--deuteron reaction applied to threshold scattering
International Nuclear Information System (INIS)
Mizutani, T.; Koltun, D.S.
1977-01-01
Scattering and absorption of pions by a nuclear target are treated together in a coupled channel theory. The theory is developed explicitly for the problem of pion scattering and absorption by a deuteron. The equations are presented in terms of the integral equations of three-body scattering theory. The method is then applied in an approximate from to calculate the contribution of pion absorption to the scattering length for pion--deuteron scattering. The sensitivity of the calculated results to the model assumptions and approximations is investigated
Decay-pion spectroscopy of light hypernuclei in the electroproduction
International Nuclear Information System (INIS)
Esser, Anselm
2014-01-01
At the Mainz Microtron, λ-hypernuclei can be produced in (e,e'K + )-reactions. By detecting the produced kaon in the KAOS spectrometer, reactions in which hyperons have been produced are tagged. The spectroscopy of charged pions, originating in weak two-body decays of light hypernuclei, allows the measurement of the binding energy of the hyperon in the nucleus with high precision. Besides the direct production of hypernuclei, they can also be produced by the fragmentation of a highly excited continuum state. This allows to study different types of hypernuclei in one experiment. High-resolution magnetic spectrometers are available for the spectroscopy of the decay-pions. To determine the ground-state mass of the hypernucleus it is crucial that the hyperfragment is stopped inside the target before it decays. Based on the known cross section of the elementary kaon photoproduction, a calculation of the expected event rate has been performed. A Monte Carlo simulation has been developed, which includes the the fragmentation and the stopping of the hyperfragments inside the target. It uses a statistical breakup model for the simulation of the fragmentation. This approach allows to predict the count rate of decay-pions from 4 λ H-hypernuclei. In a pioneering experiment, performed in 2011, for the first time hadrons could be detected with the KAOS spectrometer at a scattering angle of 0 in coincidence with pions. It became apparent that, due to the high background rate of positrons in KAOS, the clean identification of hypernuclei was impossible in the original set-up. Based on these findings, the KAOS spectrometer was modified to function as a dedicated kaon-tagger. To achieve this, an absorber made of lead was placed inside the spectrometer to stop positrons by producing electromagnetic showers. The effect of such an absorber was studied in a beam test. A simulation based on Geant4 was developed to optimise the set-up of absorber and detectors, and to predict the impact
Abelev, Betty Bezverkhny; Adamova, Dagmar; Aggarwal, Madan Mohan; Aglieri Rinella, Gianluca; Agnello, Michelangelo; Agostinelli, Andrea; Agrawal, Neelima; Ahammed, Zubayer; Ahmad, Nazeer; Ahmad, Arshad; Ahmed, Ijaz; Ahn, Sang Un; Ahn, Sul-Ah; Aimo, Ilaria; Aiola, Salvatore; Ajaz, Muhammad; Akindinov, Alexander; Aleksandrov, Dmitry; Alessandro, Bruno; Alexandre, Didier; Alici, Andrea; Alkin, Anton; Alme, Johan; Alt, Torsten; Altini, Valerio; Altinpinar, Sedat; Altsybeev, Igor; Alves Garcia Prado, Caio; Andrei, Cristian; Andronic, Anton; Anguelov, Venelin; Anielski, Jonas; Anticic, Tome; Antinori, Federico; Antonioli, Pietro; Aphecetche, Laurent Bernard; Appelshaeuser, Harald; Arbor, Nicolas; Arcelli, Silvia; Armesto Perez, Nestor; Arnaldi, Roberta; Aronsson, Tomas; Arsene, Ionut Cristian; Arslandok, Mesut; Augustinus, Andre; Averbeck, Ralf Peter; Awes, Terry; Azmi, Mohd Danish; Bach, Matthias Jakob; Badala, Angela; Baek, Yong Wook; Bagnasco, Stefano; Bailhache, Raphaelle Marie; Bairathi, Vipul; Bala, Renu; Baldisseri, Alberto; Baltasar Dos Santos Pedrosa, Fernando; Ban, Jaroslav; Baral, Rama Chandra; Barbera, Roberto; Barile, Francesco; Barnafoldi, Gergely Gabor; Barnby, Lee Stuart; Ramillien Barret, Valerie; Bartke, Jerzy Gustaw; Basile, Maurizio; Bastid, Nicole; Basu, Sumit; Bathen, Bastian; Batigne, Guillaume; Batyunya, Boris; Batzing, Paul Christoph; Baumann, Christoph Heinrich; Bearden, Ian Gardner; Beck, Hans; Bedda, Cristina; Behera, Nirbhay Kumar; Belikov, Iouri; Bellini, Francesca; Bellwied, Rene; Belmont Moreno, Ernesto; Bencedi, Gyula; Beole, Stefania; Berceanu, Ionela; Bercuci, Alexandru; Berdnikov, Yaroslav; Berenyi, Daniel; Berger, Martin Emanuel; Bertens, Redmer Alexander; Berzano, Dario; Betev, Latchezar; Bhasin, Anju; Bhati, Ashok Kumar; Bhattacharjee, Buddhadeb; Bhom, Jihyun; Bianchi, Livio; Bianchi, Nicola; Bianchin, Chiara; Bielcik, Jaroslav; Bielcikova, Jana; Bilandzic, Ante; Bjelogrlic, Sandro; Blanco, Fernando; Blau, Dmitry; Blume, Christoph; Bock, Friederike; Boehmer, Felix Valentin; Bogdanov, Alexey; Boggild, Hans; Bogolyubskiy, Mikhail; Boldizsar, Laszlo; Bombara, Marek; Book, Julian Heinz; Borel, Herve; Borissov, Alexander; Bornschein, Joerg; Bossu, Francesco; Botje, Michiel; Botta, Elena; Boettger, Stefan; Braun-Munzinger, Peter; Breitner, Timo Gunther; Broker, Theo Alexander; Browning, Tyler Allen; Broz, Michal; Bruna, Elena; Bruno, Giuseppe Eugenio; Budnikov, Dmitry; Buesching, Henner; Bufalino, Stefania; Buncic, Predrag; Busch, Oliver; Buthelezi, Edith Zinhle; Caffarri, Davide; Cai, Xu; Caines, Helen Louise; Caliva, Alberto; Calvo Villar, Ernesto; Camerini, Paolo; Canoa Roman, Veronica; Carena, Francesco; Carena, Wisla; Carminati, Federico; Casanova Diaz, Amaya Ofelia; Castillo Castellanos, Javier Ernesto; Casula, Ester Anna Rita; Catanescu, Vasile Ioan; Cavicchioli, Costanza; Ceballos Sanchez, Cesar; Cepila, Jan; Cerello, Piergiorgio; Chang, Beomsu; Chapeland, Sylvain; Charvet, Jean-Luc Fernand; Chattopadhyay, Subhasis; Chattopadhyay, Sukalyan; Cherney, Michael Gerard; Cheshkov, Cvetan Valeriev; Cheynis, Brigitte; Chibante Barroso, Vasco Miguel; Dobrigkeit Chinellato, David; Chochula, Peter; Chojnacki, Marek; Choudhury, Subikash; Christakoglou, Panagiotis; Christensen, Christian Holm; Christiansen, Peter; Chujo, Tatsuya; Chung, Suh-Urk; Cicalo, Corrado; Cifarelli, Luisa; Cindolo, Federico; Cleymans, Jean Willy Andre; Colamaria, Fabio Filippo; Colella, Domenico; Collu, Alberto; Colocci, Manuel; Conesa Balbastre, Gustavo; Conesa Del Valle, Zaida; Connors, Megan Elizabeth; Contin, Giacomo; Contreras Nuno, Jesus Guillermo; Cormier, Thomas Michael; Corrales Morales, Yasser; Cortese, Pietro; Cortes Maldonado, Ismael; Cosentino, Mauro Rogerio; Costa, Filippo; Crochet, Philippe; Cruz Albino, Rigoberto; Cuautle Flores, Eleazar; Cunqueiro Mendez, Leticia; Dainese, Andrea; Dang, Ruina; Danu, Andrea; Das, Debasish; Das, Indranil; Das, Kushal; Das, Supriya; Dash, Ajay Kumar; Dash, Sadhana; De, Sudipan; Delagrange, Hugues; Deloff, Andrzej; Denes, Ervin Sandor; D'Erasmo, Ginevra; Oliveira Valeriano De Barros, Gabriel; De Caro, Annalisa; De Cataldo, Giacinto; De Cuveland, Jan; De Falco, Alessandro; De Gruttola, Daniele; De Marco, Nora; De Pasquale, Salvatore; De Rooij, Raoul Stefan; Diaz Corchero, Miguel Angel; Dietel, Thomas; Divia, Roberto; Di Bari, Domenico; Di Liberto, Sergio; Di Mauro, Antonio; Di Nezza, Pasquale; Djuvsland, Oeystein; Dobrin, Alexandru Florin; Dobrowolski, Tadeusz Antoni; Domenicis Gimenez, Diogenes; Donigus, Benjamin; Dordic, Olja; Dorheim, Sverre; Dubey, Anand Kumar; Dubla, Andrea; Ducroux, Laurent; Dupieux, Pascal; Dutt Mazumder, Abhee Kanti; Ehlers Iii, Raymond James; Elia, Domenico; Engel, Heiko; Erazmus, Barbara Ewa; Erdal, Hege Austrheim; Eschweiler, Dominic; Espagnon, Bruno; Estienne, Magali Danielle; Esumi, Shinichi; Evans, David; Evdokimov, Sergey; Eyyubova, Gyulnara; Fabris, Daniela; Faivre, Julien; Falchieri, Davide; Fantoni, Alessandra; Fasel, Markus; Fehlker, Dominik; Feldkamp, Linus; Felea, Daniel; Feliciello, Alessandro; Feofilov, Grigory; Ferencei, Jozef; Fernandez Tellez, Arturo; Gonzalez Ferreiro, Elena; Ferretti, Alessandro; Festanti, Andrea; Figiel, Jan; Araujo Silva Figueredo, Marcel; Filchagin, Sergey; Finogeev, Dmitry; Fionda, Fiorella; Fiore, Enrichetta Maria; Floratos, Emmanouil; Floris, Michele; Foertsch, Siegfried Valentin; Foka, Panagiota; Fokin, Sergey; Fragiacomo, Enrico; Francescon, Andrea; Frankenfeld, Ulrich Michael; Fuchs, Ulrich; Furget, Christophe; Fusco Girard, Mario; Gaardhoeje, Jens Joergen; Gagliardi, Martino; Gallio, Mauro; Gangadharan, Dhevan Raja; Ganoti, Paraskevi; Garabatos Cuadrado, Jose; Garcia-Solis, Edmundo Javier; Gargiulo, Corrado; Garishvili, Irakli; Gerhard, Jochen; Germain, Marie; Gheata, Andrei George; Gheata, Mihaela; Ghidini, Bruno; Ghosh, Premomoy; Ghosh, Sanjay Kumar; Gianotti, Paola; Giubellino, Paolo; Gladysz-Dziadus, Ewa; Glassel, Peter; Gomez Jimenez, Ramon; Gonzalez Zamora, Pedro; Gorbunov, Sergey; Gorlich, Lidia Maria; Gotovac, Sven; Graczykowski, Lukasz Kamil; Grajcarek, Robert; Grelli, Alessandro; Grigoras, Alina Gabriela; Grigoras, Costin; Grigoryev, Vladislav; Grigoryan, Ara; Grigoryan, Smbat; Grynyov, Borys; Grion, Nevio; Grosse-Oetringhaus, Jan Fiete; Grossiord, Jean-Yves; Grosso, Raffaele; Guber, Fedor; Guernane, Rachid; Guerzoni, Barbara; Guilbaud, Maxime Rene Joseph; Gulbrandsen, Kristjan Herlache; Gulkanyan, Hrant; Gunji, Taku; Gupta, Anik; Gupta, Ramni; Khan, Kamal; Haake, Rudiger; Haaland, Oystein Senneset; Hadjidakis, Cynthia Marie; Haiduc, Maria; Hamagaki, Hideki; Hamar, Gergoe; Hanratty, Luke David; Hansen, Alexander; Harris, John William; Hartmann, Helvi; Harton, Austin Vincent; Hatzifotiadou, Despina; Hayashi, Shinichi; Heckel, Stefan Thomas; Heide, Markus Ansgar; Helstrup, Haavard; Herghelegiu, Andrei Ionut; Herrera Corral, Gerardo Antonio; Hess, Benjamin Andreas; Hetland, Kristin Fanebust; Hicks, Bernard Richard; Hippolyte, Boris; Hladky, Jan; Hristov, Peter Zahariev; Huang, Meidana; Humanic, Thomas; Hutter, Dirk; Hwang, Dae Sung; Ilkaev, Radiy; Ilkiv, Iryna; Inaba, Motoi; Incani, Elisa; Innocenti, Gian Michele; Ionita, Costin; Ippolitov, Mikhail; Irfan, Muhammad; Ivanov, Marian; Ivanov, Vladimir; Ivanytskyi, Oleksii; Jacholkowski, Adam Wlodzimierz; Jahnke, Cristiane; Jang, Haeng Jin; Janik, Malgorzata Anna; Pahula Hewage, Sandun; Jena, Satyajit; Jimenez Bustamante, Raul Tonatiuh; Jones, Peter Graham; Jung, Hyungtaik; Jusko, Anton; Kalcher, Sebastian; Kalinak, Peter; Kalweit, Alexander Philipp; Kamin, Jason Adrian; Kang, Ju Hwan; Kaplin, Vladimir; Kar, Somnath; Karasu Uysal, Ayben; Karavichev, Oleg; Karavicheva, Tatiana; Karpechev, Evgeny; Kebschull, Udo Wolfgang; Keidel, Ralf; Ketzer, Bernhard Franz; Khan, Mohammed Mohisin; Khan, Palash; Khan, Shuaib Ahmad; Khanzadeev, Alexei; Kharlov, Yury; Kileng, Bjarte; Kim, Beomkyu; Kim, Do Won; Kim, Dong Jo; Kim, Jinsook; Kim, Mimae; Kim, Minwoo; Kim, Se Yong; Kim, Taesoo; Kirsch, Stefan; Kisel, Ivan; Kiselev, Sergey; Kisiel, Adam Ryszard; Kiss, Gabor; Klay, Jennifer Lynn; Klein, Jochen; Klein-Boesing, Christian; Kluge, Alexander; Knichel, Michael Linus; Knospe, Anders Garritt; Kobdaj, Chinorat; Kofarago, Monika; Kohler, Markus Konrad; Kollegger, Thorsten; Kolozhvari, Anatoly; Kondratev, Valerii; Kondratyeva, Natalia; Konevskikh, Artem; Kovalenko, Vladimir; Kowalski, Marek; Kox, Serge; Koyithatta Meethaleveedu, Greeshma; Kral, Jiri; Kralik, Ivan; Kramer, Frederick; Kravcakova, Adela; Krelina, Michal; Kretz, Matthias; Krivda, Marian; Krizek, Filip; Krus, Miroslav; Kryshen, Evgeny; Krzewicki, Mikolaj; Kucera, Vit; Kucheryaev, Yury; Kugathasan, Thanushan; Kuhn, Christian Claude; Kuijer, Paulus Gerardus; Kulakov, Igor; Kumar, Jitendra; Kurashvili, Podist; Kurepin, Alexander; Kurepin, Alexey; Kuryakin, Alexey; Kushpil, Svetlana; Kushpil, Vasilij; Kweon, Min Jung; Kwon, Youngil; Ladron De Guevara, Pedro; Lagana Fernandes, Caio; Lakomov, Igor; Langoy, Rune; Lara Martinez, Camilo Ernesto; Lardeux, Antoine Xavier; Lattuca, Alessandra; La Pointe, Sarah Louise; La Rocca, Paola; Lea, Ramona; Lee, Graham Richard; Legrand, Iosif; Lehnert, Joerg Walter; Lemmon, Roy Crawford; Lenhardt, Matthieu Laurent; Lenti, Vito; Leogrande, Emilia; Leoncino, Marco; Leon Monzon, Ildefonso; Levai, Peter; Li, Shuang; Lien, Jorgen Andre; Lietava, Roman; Lindal, Svein; Lindenstruth, Volker; Lippmann, Christian; Lisa, Michael Annan; Ljunggren, Hans Martin; Lodato, Davide Francesco; Lonne, Per-Ivar; Loggins, Vera Renee; Loginov, Vitaly; Lohner, Daniel; Loizides, Constantinos; Lopez, Xavier Bernard; Lopez Torres, Ernesto; Lu, Xianguo; Luettig, Philipp Johannes; Lunardon, Marcello; Luo, Jiebin; Luparello, Grazia; Luzzi, Cinzia; Gago Medina, Alberto Martin; Jacobs, Peter Martin; Ma, Rongrong; Maevskaya, Alla; Mager, Magnus; Mahapatra, Durga Prasad; Maire, Antonin; Malaev, Mikhail; Maldonado Cervantes, Ivonne Alicia; Malinina, Liudmila; Mal'Kevich, Dmitry; Malzacher, Peter; Mamonov, Alexander; Manceau, Loic Henri Antoine; Manko, Vladislav; Manso, Franck; Manzari, Vito; Marchisone, Massimiliano; Mares, Jiri; Margagliotti, Giacomo Vito; Margotti, Anselmo; Marin, Ana Maria; Markert, Christina; Marquard, Marco; Martashvili, Irakli; Martin, Nicole Alice; Martinengo, Paolo; Martinez Hernandez, Mario Ivan; Martinez-Garcia, Gines; Martin Blanco, Javier; Martynov, Yevgen; Mas, Alexis Jean-Michel; Masciocchi, Silvia; Masera, Massimo; Masoni, Alberto; Massacrier, Laure Marie; Mastroserio, Annalisa; Matyja, Adam Tomasz; Mayer, Christoph; Mazer, Joel Anthony; Mazumder, Rakesh; Mazzoni, Alessandra Maria; Meddi, Franco; Menchaca-Rocha, Arturo Alejandro; Mercado-Perez, Jorge; Meres, Michal; Miake, Yasuo; Mikhaylov, Konstantin; Milano, Leonardo; Milosevic, Jovan; Mischke, Andre; Mishra, Aditya Nath; Miskowiec, Dariusz Czeslaw; Mitu, Ciprian Mihai; Mlynarz, Jocelyn; Mohanty, Bedangadas; Molnar, Levente; Montano Zetina, Luis Manuel; Montes Prado, Esther; Morando, Maurizio; Moreira De Godoy, Denise Aparecida; Moretto, Sandra; Morreale, Astrid; Morsch, Andreas; Muccifora, Valeria; Mudnic, Eugen; Muhuri, Sanjib; Mukherjee, Maitreyee; Muller, Hans; Gameiro Munhoz, Marcelo; Murray, Sean; Musa, Luciano; Musinsky, Jan; Nandi, Basanta Kumar; Nania, Rosario; Nappi, Eugenio; Nattrass, Christine; Nayak, Tapan Kumar; Nazarenko, Sergey; Nedosekin, Alexander; Nicassio, Maria; Niculescu, Mihai; Nielsen, Borge Svane; Nikolaev, Sergey; Nikulin, Sergey; Nikulin, Vladimir; Nilsen, Bjorn Steven; Noferini, Francesco; Nomokonov, Petr; Nooren, Gerardus; Nyanin, Alexander; Nystrand, Joakim Ingemar; Oeschler, Helmut Oskar; Oh, Saehanseul; Oh, Sun Kun; Okatan, Ali; Olah, Laszlo; Oleniacz, Janusz; Oliveira Da Silva, Antonio Carlos; Onderwaater, Jacobus; Oppedisano, Chiara; Ortiz Velasquez, Antonio; Oskarsson, Anders Nils Erik; Otwinowski, Jacek Tomasz; Oyama, Ken; Pachmayer, Yvonne Chiara; Pachr, Milos; Pagano, Paola; Paic, Guy; Painke, Florian; Pajares Vales, Carlos; Pal, Susanta Kumar; Palmeri, Armando; Pant, Divyash; Papikyan, Vardanush; Pappalardo, Giuseppe; Park, Woojin; Passfeld, Annika; Patalakha, Dmitry; Paticchio, Vincenzo; Paul, Biswarup; Pawlak, Tomasz Jan; Peitzmann, Thomas; Pereira Da Costa, Hugo Denis Antonio; Pereira De Oliveira Filho, Elienos; Peresunko, Dmitry Yurevich; Perez Lara, Carlos Eugenio; Peryt, Wiktor Stanislaw; Pesci, Alessandro; Pestov, Yury; Petracek, Vojtech; Petran, Michal; Petris, Mariana; Petrovici, Mihai; Petta, Catia; Piano, Stefano; Pikna, Miroslav; Pillot, Philippe; Pinazza, Ombretta; Pinsky, Lawrence; Piyarathna, Danthasinghe; Ploskon, Mateusz Andrzej; Planinic, Mirko; Pluta, Jan Marian; Pochybova, Sona; Podesta Lerma, Pedro Luis Manuel; Poghosyan, Martin; Pohjoisaho, Esko Heikki Oskari; Polishchuk, Boris; Poljak, Nikola; Pop, Amalia; Porteboeuf, Sarah Julie; Porter, R Jefferson; Pospisil, Vladimir; Potukuchi, Baba; Prasad, Sidharth Kumar; Preghenella, Roberto; Prino, Francesco; Pruneau, Claude Andre; Pshenichnov, Igor; Puddu, Giovanna; Punin, Valery; Putschke, Jorn Henning; Qvigstad, Henrik; Rachevski, Alexandre; Raha, Sibaji; Rak, Jan; Rakotozafindrabe, Andry Malala; Ramello, Luciano; Raniwala, Rashmi; Raniwala, Sudhir; Rasanen, Sami Sakari; Rascanu, Bogdan Theodor; Rathee, Deepika; Rauf, Aamer Wali; Razazi, Vahedeh; Read, Kenneth Francis; Real, Jean-Sebastien; Redlich, Krzysztof; Reed, Rosi Jan; Rehman, Attiq Ur; Reichelt, Patrick Simon; Reicher, Martijn; Reidt, Felix; Renfordt, Rainer Arno Ernst; Reolon, Anna Rita; Reshetin, Andrey; Rettig, Felix Vincenz; Revol, Jean-Pierre; Reygers, Klaus Johannes; Riabov, Viktor; Ricci, Renato Angelo; Richert, Tuva Ora Herenui; Richter, Matthias Rudolph; Riedler, Petra; Riegler, Werner; Riggi, Francesco; Rivetti, Angelo; Rocco, Elena; Rodriguez Cahuantzi, Mario; Rodriguez Manso, Alis; Roeed, Ketil; Rogochaya, Elena; Sharma, Rohni; Rohr, David Michael; Roehrich, Dieter; Romita, Rosa; Ronchetti, Federico; Ronflette, Lucile; Rosnet, Philippe; Rossegger, Stefan; Rossi, Andrea; Roy, Ankhi; Roy, Christelle Sophie; Roy, Pradip Kumar; Rubio Montero, Antonio Juan; Rui, Rinaldo; Russo, Riccardo; Ryabinkin, Evgeny; Ryabov, Yury; Rybicki, Andrzej; Sadovskiy, Sergey; Safarik, Karel; Sahlmuller, Baldo; Sahoo, Raghunath; Sahu, Pradip Kumar; Saini, Jogender; Salgado Lopez, Carlos Alberto; Salzwedel, Jai Samuel Nielsen; Sambyal, Sanjeev Singh; Samsonov, Vladimir; Sanchez Castro, Xitzel; Sanchez Rodriguez, Fernando Javier; Sandor, Ladislav; Sandoval, Andres; Sano, Masato; Santagati, Gianluca; Sarkar, Debojit; Scapparone, Eugenio; Scarlassara, Fernando; Scharenberg, Rolf Paul; Schiaua, Claudiu Cornel; Schicker, Rainer Martin; Schmidt, Christian Joachim; Schmidt, Hans Rudolf; Schuchmann, Simone; Schukraft, Jurgen; Schulc, Martin; Schuster, Tim Robin; Schutz, Yves Roland; Schwarz, Kilian Eberhard; Schweda, Kai Oliver; Scioli, Gilda; Scomparin, Enrico; Scott, Patrick Aaron; Scott, Rebecca Michelle; Segato, Gianfranco; Seger, Janet Elizabeth; Selyuzhenkov, Ilya; Seo, Jeewon; Serradilla Rodriguez, Eulogio; Sevcenco, Adrian; Shabetai, Alexandre; Shabratova, Galina; Shahoyan, Ruben; Shangaraev, Artem; Sharma, Natasha; Sharma, Satish; Shigaki, Kenta; Shtejer Diaz, Katherin; Sibiryak, Yury; Siddhanta, Sabyasachi; Siemiarczuk, Teodor; Silvermyr, David Olle Rickard; Silvestre, Catherine Micaela; Simatovic, Goran; Singaraju, Rama Narayana; Singh, Ranbir; Singha, Subhash; Singhal, Vikas; Sinha, Bikash; Sarkar - Sinha, Tinku; Sitar, Branislav; Sitta, Mario; Skaali, Bernhard; Skjerdal, Kyrre; Smakal, Radek; Smirnov, Nikolai; Snellings, Raimond; Soegaard, Carsten; Soltz, Ron Ariel; Song, Jihye; Song, Myunggeun; Soramel, Francesca; Sorensen, Soren Pontoppidan; Spacek, Michal; Sputowska, Iwona Anna; Spyropoulou-Stassinaki, Martha; Srivastava, Brijesh Kumar; Stachel, Johanna; Stan, Ionel; Stefanek, Grzegorz; Steinpreis, Matthew Donald; Stenlund, Evert Anders; Steyn, Gideon Francois; Stiller, Johannes Hendrik; Stocco, Diego; Stolpovskiy, Mikhail; Strmen, Peter; Alarcon Do Passo Suaide, Alexandre; Subieta Vasquez, Martin Alfonso; Sugitate, Toru; Suire, Christophe Pierre; Suleymanov, Mais Kazim Oglu; Sultanov, Rishat; Sumbera, Michal; Susa, Tatjana; Symons, Timothy; Szanto De Toledo, Alejandro; Szarka, Imrich; Szczepankiewicz, Adam; Szymanski, Maciej Pawel; Takahashi, Jun; Tangaro, Marco-Antonio; Tapia Takaki, Daniel Jesus; Tarantola Peloni, Attilio; Tarazona Martinez, Alfonso; Tauro, Arturo; Tejeda Munoz, Guillermo; Telesca, Adriana; Terrevoli, Cristina; Ter-Minasyan, Astkhik; Thaeder, Jochen Mathias; Thomas, Deepa; Tieulent, Raphael Noel; Timmins, Anthony Robert; Toia, Alberica; Torii, Hisayuki; Trubnikov, Victor; Trzaska, Wladyslaw Henryk; Tsuji, Tomoya; Tumkin, Alexandr; Turrisi, Rosario; Tveter, Trine Spedstad; Ulery, Jason Glyndwr; Ullaland, Kjetil; Uras, Antonio; Usai, Gianluca; Vajzer, Michal; Vala, Martin; Valencia Palomo, Lizardo; Vallero, Sara; Vande Vyvre, Pierre; Vannucci, Luigi; Van Der Maarel, Jasper; Van Hoorne, Jacobus Willem; Van Leeuwen, Marco; Diozcora Vargas Trevino, Aurora; Varma, Raghava; Vasileiou, Maria; Vasiliev, Andrey; Vechernin, Vladimir; Veldhoen, Misha; Velure, Arild; Venaruzzo, Massimo; Vercellin, Ermanno; Vergara Limon, Sergio; Vernet, Renaud; Verweij, Marta; Vickovic, Linda; Viesti, Giuseppe; Viinikainen, Jussi Samuli; Vilakazi, Zabulon; Villalobos Baillie, Orlando; Vinogradov, Alexander; Vinogradov, Leonid; Vinogradov, Yury; Virgili, Tiziano; Viyogi, Yogendra; Vodopyanov, Alexander; Volkl, Martin Andreas; Voloshin, Kirill; Voloshin, Sergey; Volpe, Giacomo; Von Haller, Barthelemy; Vorobyev, Ivan; Vranic, Danilo; Vrlakova, Janka; Vulpescu, Bogdan; Vyushin, Alexey; Wagner, Boris; Wagner, Jan; Wagner, Vladimir; Wang, Mengliang; Wang, Yifei; Watanabe, Daisuke; Weber, Michael; Wessels, Johannes Peter; Westerhoff, Uwe; Wiechula, Jens; Wikne, Jon; Wilde, Martin Rudolf; Wilk, Grzegorz Andrzej; Wilkinson, Jeremy John; Williams, Crispin; Windelband, Bernd Stefan; Winn, Michael Andreas; Xiang, Changzhou; Yaldo, Chris G; Yamaguchi, Yorito; Yang, Hongyan; Yang, Ping; Yang, Shiming; Yano, Satoshi; Yasnopolskiy, Stanislav; Yi, Jungyu; Yin, Zhongbao; Yoo, In-Kwon; Yushmanov, Igor; Zaccolo, Valentina; Zach, Cenek; Zaman, Ali; Zampolli, Chiara; Zaporozhets, Sergey; Zarochentsev, Andrey; Zavada, Petr; Zavyalov, Nikolay; Zbroszczyk, Hanna Paulina; Zgura, Sorin Ion; Zhalov, Mikhail; Zhang, Fan; Zhang, Haitao; Zhang, Xiaoming; Zhang, Yonghong; Zhao, Chengxin; Zhou, Daicui; Zhou, Fengchu; Zhou, You; Zhu, Hongsheng; Zhu, Jianhui; Zhu, Jianlin; Zhu, Xiangrong; Zichichi, Antonino; Zimmermann, Alice; Zimmermann, Markus Bernhard; Zinovjev, Gennady; Zoccarato, Yannick Denis; Zynovyev, Mykhaylo; Zyzak, Maksym
2014-07-07
Transverse momentum spectra of $\\pi^{\\pm}, K^{\\pm}$ and $p(\\bar{p})$ up to $p_T$ = 20 GeV/c at mid-rapidity, |y| $\\le$ 0.8, in pp and Pb-Pb collisions at $\\sqrt{s_{NN}}$ = 2.76 TeV have been measured using the ALICE detector at the LHC. At intermediate $p_T$ (2-8 GeV/c) an enhancement of the proton-to-proton ratio, (p + $\\bar{p})/(\\pi^+ + \\pi^-$), with respect to pp collisions is observed and the ratio reaches ~0.80 in central Pb-Pb collisions. The measurement of the nuclear modification factors for $\\pi^{\\pm}, K^{\\pm}$ and $p(\\bar{p})$ indicates that within the systematic and statistical uncertainties they are the same at high $p_T$ (> 10 GeV/c), suggesting that the chemical composition of leading particles from jets in the medium is similar to that of vacuum jets.
Czech Academy of Sciences Publication Activity Database
Abelev, B.; Adam, J.; Adamová, Dagmar; Bielčík, J.; Bielčíková, Jana; Brož, M.; Čepila, J.; Ferencei, Jozef; Hladký, Jan; Křelina, M.; Křížek, Filip; Krus, M.; Kučera, Vít; Kushpil, Svetlana; Kushpil, Vasilij; Mareš, Jiří A.; Pachr, M.; Petráček, V.; Petráň, M.; Pospíšil, V.; Schulc, M.; Šmakal, R.; Špaček, M.; Šumbera, Michal; Vajzer, Michal; Wagner, V.; Zach, Č.; Závada, Petr
Roč. 736, SEP ( 2014 ), s. 196-207 ISSN 0370-2693 R&D Projects: GA MŠk(CZ) LG13031 Institutional support: RVO:68378271 ; RVO:61389005 Keywords : ALICE * LHC * identified particle production * high p(T) * particle ratios * baryon anomaly * nuclear modification factor Subject RIV: BG - Nuclear , Atomic and Molecular Physics, Colliders; BF - Elementary Particles and High Energy Physics (FZU-D) Impact factor: 6.131, year: 2014
Generation of particles with large transverse momenta in π--p- and π-12C-interactions at 40 GeV/c
International Nuclear Information System (INIS)
Jordanova, Yu.; Lyubimov, V.; Mitova, S.; Penev, V.N.; Shklovskaya, A.
1981-01-01
The generation of a particle with transverse momenta Psub(transverse)>0.8 GeV/c in π - -p- and π - - 12 C-interactions with a π - -meson beam at a momentum Psub(π)=40 GeV/c in a two-meter propan chamber is investigated. Analyses of the secondary particle correlations produced in the interactions, in which the emitted hadron or group of hadrons have large transverse momenta, are carried out. In the investigated interactions the secondary particle momenta are measured with an accuracy not less than 30%. In the experimental data treatment of the π - - 12 C-collisions the interactions of π - -mesons with the quasifree nucleons of 12 C-nucleus are taken into account on the basis of the multiperipherical model. The experimental data analyses indicate that: 1) In the events with one or more secondary particles having large momenta Psub(transverse)>0.8 GeV/c the asymmetric correlations increase for both π - -p- and π - - 12 C-interactions; 2) Most correlated pairs of secondary particles having Psub(transverse)>0.8 GeV/c are produced with an almost equal rapidity and transverse momenta; 3) The presence of the secondary particles with large transverse momenta does not influence the resonance formation (in particular rho 0 -meson); 4) The effective mass distribution of the two secondary particles with Psub(transverse)>0.8 GeV/c has a broad peak at about 2 GeV/c
Directory of Open Access Journals (Sweden)
Sharf Igor
2013-11-01
Full Text Available We consider the hadron–hadron inelastic scattering in the framework of QCD perturbation theory. It is shown that in QCD, due to conservation of color, the tree-level diagrams of inelastic scattering are prohibited and one has to deal with the diagrams with loops. We examine the simplest type of such diagrams, where the diagram can be split into blocks, so that the integration over four-momenta of virtual particles in each block can be done independently. It is shown that for these diagrams the squared absolute value of scattering amplitude has a maximum point, similar to that observed earlier in ɸ3 model, if one takes into account the relations between the arguments of scattering amplitude, imposed by the energy-momentum conservation law. This enables to apply the Laplace’s method for the calculation of cross section of hadron–hadron inelastic scattering. It is shown that the diagrams of gluon-loop exchange in QCD are equivalent to the diagrams of pion exchange in ɸ3 theory, whereby the new mechanism of cross section growth, discovered earlier in ɸ3 theory, takes place also in the perturbative QCD. The latter may explain the origin of experimentally-observed growth of cross section of hadron–hadron inelastic scattering as function of energy of colliding hadrons. The discovered mechanism can’t emerge in any Regge-based model due to the premises on the particle kinematics, made in these models.
Mulders, P. J.
2018-03-01
Light-front quantized quark and gluon states (partons) play a dominant role in high energy scattering processes. Initial state hadrons are mixed ensembles of partons, while produced pure partonic states appear as mixed ensembles of hadrons. The transition from collinear hard physics to the 3D structure including partonic transverse momenta is related to confinement which links color and spatial degrees of freedom. We outline ideas on emergent symmetries in the Standard Model and their connection to the 3D structure of hadrons. Wilson loops, including those with light-like Wilson lines such as used in the studies of transverse momentum dependent distribution functions may play a crucial role here, establishing a direct link between transverse spatial degrees of freedom and gluonic degrees of freedom.
Analysis of alignment of particle momenta in anti pp interactions at 22.4 GeV/c
International Nuclear Information System (INIS)
Booc, Eh.G.; Ermilova, D.I.; Samojlov, V.V.
1980-01-01
The data are presented on the azimuthal correlations in anti pp interactions at 22.4 GeV/c. The difference observed between the distributions of pairs of particles with equal and different charges cannot the completely explained by the interference effect of identical particles or by the presence of leading particles and resonances. The study on the planarity indicates the alignment of transverse momenta of secondary particles. This alignment is independent of the multiplicity of charged particles and is not connected with the interference effect of identical particles and with leading particles. An assymmetry in the azimuthal angle distribution of beam particle (phisub(B)) observed in the system of principal axes is not described in the framework of the cylindrical phase space
Forward-backward correlations between mean transverse momenta in Pb-Pb collisions with ALICE arXiv
Altsybeev, Igor
Forward-backward (FB) correlations are considered to be a powerful tool for the exploration of the early dynamics of hadronic interactions. The FB correlation functions can be constructed from different observables calculated event-by-event in two separated pseudorapidity regions. We report measurements of event-by-event average transverse momentum correlations for charged particles in two separated pseudorapidity regions in Pb-Pb collisions at $\\sqrt{s_{\\rm NN}}=2.76$ and 5.02 TeV recorded with ALICE at the LHC. The event-by-event mean transverse momenta correlations are robust against volume fluctuations and thus the centrality determination methods, which provides higher sensitivity to the properties of the initial state and evolution of the medium created in A-A collisions. The strength of the FB correlation is calculated for different centralities of the Pb-Pb collisions. Results are compared with Monte Carlo event generators, such as HIJING and AMPT.
Pion-nucleon scattering in the chiral bag model
International Nuclear Information System (INIS)
Israilov, Z.Z.; Musakhanov, M.M.
1981-01-01
Pion-nucleon scattering in the (3.3) resonance region in the framework of chiral bag model(CBM) is considered. The effective Hamiltonian of πNΔ-system in the framework of the CBM contains πNN, πNΔ, πΔΔ interaction terms with the formfactor which is essentially dependent on the size and shape of the quark bag. The iteration of the Born graphs of this model provides successful description of the (3.3) and (3.1) scattering where the values of the parameters agree with CBM [ru
Non-perturbative pion dynamics for the X(3872
Directory of Open Access Journals (Sweden)
Baru V.
2014-01-01
Full Text Available We discuss the role of non-perturbative pion dynamics on the near-threshold resonant X(3872 charmonium state, which is assumed to be an S-wave DD̄* bound system. We calculate the contribution to the width of the X(3872 from the DD̄π intermediate state treated non-perturbatively and compare it with different approximate approaches. Further, we explore the quark-mass dependence of the pole position of the X(3872 state. We find that the trajectory of the X(3872 depends strongly on the assumed quark-mass dependence of the short-range interactions which can be determined in lattice QCD calculations.
Pions to quarks: particle physics in the 1950s
International Nuclear Information System (INIS)
Brown, L.M.
1989-01-01
This chapter charts particle physics discoveries between 1947 and 1963, starting with the theory of the Yukawa meson, the pion and the first strange particles and ending with the discovery of two neutrinos, new pseudoscalar and vector mesons and charge-parity violations. Technically, this change from cosmic rays to accelerators as sources for high-energy experiments was significant, and detectors developed rapidly into large bubble chambers, scintillation counters and spark chambers, while computers were becoming more common for data analysis. In the post-war boom, large amounts of government funds were provided. (UK)
Pade approximants in field theory: pion and kaon systems
International Nuclear Information System (INIS)
Zinn-Justin, J.
1969-01-01
We construct the Pade approximants of the S-matrix, starting from the perturbation series, in the case of two body pion and kaon systems. We have three parameters. The seven lowest lying two body resonances (ρ, K * (890), φ, K * (1420), f 0 , f', A 2 ) are obtained within a few per cent of their actual masses. The Regge trajectories are rising, the intercepts of the ρ and f 0 agree well with the experimental values. In the appendices we give some properties and applications of the Pade approximants. (author) [fr
Design studies of a proton-pion hodoscope
International Nuclear Information System (INIS)
Charagi, S.K.; Gupta, S.K.; Chatterjee, A.
1987-01-01
The considerations for the design of a detector assembly for detecting pions and protons resulting from the decay of Δ + in the reaction 6 Li(p,Δ ++ ) 6 He at 400-500 MeV are discussed. The details of a computer program to calculate efficiencies for different hodoscope geometries and numerical results for some specific cases are given. A method for reconstructing the full kinematics of a reaction event from the position information of particle hits in the hodoscope is presented. (author)
Conformal invariance and pion wave functions of nonleading twist
International Nuclear Information System (INIS)
Braun, V.M.; Filyanov, I.E.
1989-01-01
The restrictions are studied for the general structure of pion wave functions of twist 3 and twist 4 imposed by the conformal symmetry and the equations of motion. A systematic expansion of wave functions in the conformal spin is built and the first order corrections to asymptotic formulae are calculated by the QCD sum rule method. In particular, we have found a multiplicatively renormalizable contribution into the two-particle wave function of twist 4 which cannot be expanded in a finite set of Gegenbauer polynomials. 19 refs.; 5 figs
On the hadron formation time in pion-nucleus interaction
International Nuclear Information System (INIS)
Bravina, L.V.; Korotkikh, V.L.; Sarycheva, L.I.; Sivoklokov, S.Yu.
1992-01-01
Differences in the observable characteristics of pion-nucleus interactions at high energy are investigated for two definitions of the hadron formation time. The Monte Carlo simulation of hadron-nucleus interactions and quark-gluon string model for hadron-hadron collisions are used. It is shown that the momentum spectrum of the protons in the target fragmentation region is most sensitive to the definition of the formation time. The inclusive meson and meson resonance spectra are similar in the both versions. 20 refs.; 4 figs.; 1 tab
Parameterized total cross sections for pion production in nuclear collisions
International Nuclear Information System (INIS)
Norbury, John W.; Townsend, Lawrence W.
2007-01-01
Total inclusive cross sections for neutral and charged pion production in proton-nucleus and nucleus-nucleus reactions have been calculated and compared to experiment. Nucleon-nucleon theoretical cross sections have been scaled up to nuclear collisions using a scaling factor similar to (A P A T ) 2/3 , where A P and A T are the nucleon numbers of the projectile and target nuclei. Variations in the power of this scaling factor have been studied and a good fit to experiment is obtained with a small modification of the power. Theoretical cross sections are written in a form that is very suitable for immediate input into transport codes
Facility for studying spin dependence in pion production near threshold
Rinckel, T; Meyer, H O; Balewski, J T; Doskow, J; Pollock, R E; Von Przewoski, B; Sperisen, F; Daehnick, W W; Flammang, R W; Saha, S K; Haeberli, W; Lorentz, B; Rathmann, F; Schwartz, B; Wise, T; Pancella, P V
2000-01-01
We describe an experimental setup for the measurement of polarization observables in pion production near threshold. Experiments carried out with this facility use a polarized proton beam in the Indiana University Cooler storage ring, and an internal, polarized hydrogen target. The detector system measures energy, direction and velocity of multiple outgoing charged particles that are within a forward cone of about 32 deg. opening angle. An array of scintillators also allows the detection of neutrons. In addition to the technical details of the apparatus, we describe the procedure for data acquisition, as well as some aspects of the analysis.
Various models for pion probability distributions from heavy-ion collisions
International Nuclear Information System (INIS)
Mekjian, A.Z.; Mekjian, A.Z.; Schlei, B.R.; Strottman, D.; Schlei, B.R.
1998-01-01
Various models for pion multiplicity distributions produced in relativistic heavy ion collisions are discussed. The models include a relativistic hydrodynamic model, a thermodynamic description, an emitting source pion laser model, and a description which generates a negative binomial description. The approach developed can be used to discuss other cases which will be mentioned. The pion probability distributions for these various cases are compared. Comparison of the pion laser model and Bose-Einstein condensation in a laser trap and with the thermal model are made. The thermal model and hydrodynamic model are also used to illustrate why the number of pions never diverges and why the Bose-Einstein correction effects are relatively small. The pion emission strength η of a Poisson emitter and a critical density η c are connected in a thermal model by η/n c =e -m/T <1, and this fact reduces any Bose-Einstein correction effects in the number and number fluctuation of pions. Fluctuations can be much larger than Poisson in the pion laser model and for a negative binomial description. The clan representation of the negative binomial distribution due to Van Hove and Giovannini is discussed using the present description. Applications to CERN/NA44 and CERN/NA49 data are discussed in terms of the relativistic hydrodynamic model. copyright 1998 The American Physical Society
Observation of the shadowing and antishadowing effects in pion-nucleus interactions
International Nuclear Information System (INIS)
Ion, D.B.; Nichitiu, F.
1977-12-01
The shadowing and antishadowing effects in the pion-nucleus interaction are investigated by using the available experimental data and the recent interpolations of the π + - p total cross sections. Pronounced shadowing is found in the energy regions of pion-nucleon resonances while the antishadowing effects are systematically observed at energies between two resonances. (author)
Recoil of the pion-surrounded nucleon bag and axial form factors
International Nuclear Information System (INIS)
Klabucar, D.; Picek, I.
1984-03-01
A recent method of boosting the bag is extended to the pion-surrounded nucleon bag and developed for the calculation of low-energy nucleon form factors. The usefulness of the method is illustrated by the induced pseudoscalar form factor where both the inclusion of the pion field and the non-vanishing momentum transfer are necessary. (Auth.)
Diffraction model analysis of pion-12C elastic scattering at 800 MeV ...
Indian Academy of Sciences (India)
Elastic scattering of 800 MeV/c pions by 12C has been studied in the diffraction model with a view to determine pion optical potential by the method of inversion. Finding an earlier diffraction model analysis to be deficient in some respects, we propose a Glauber model based parametrization for the elastic -matrix and show ...
Single transverse-spin asymmetry in high transverse momentum pion production in pp collisions
DEFF Research Database (Denmark)
Kouvaris, Christoforos; Qiu, Jian-Wei; Vogelsang, Werner
2006-01-01
We study the single-spin (left-right) asymmetry in single-inclusive pion production in hadronic scattering. This asymmetry is power-suppressed in the transverse momentum of the produced pion and can be analyzed in terms of twist-three parton correlation functions in the proton. We present new...
Emission patterns of neutral pions in 40A MeV Ta plus Au reactions
Piasecki, K.; Matulewicz, T.; Yahlali, N.; Delagrange, H.; Diaz, J.; d'Enterria, D. G.; Fernandez, F.; Kugler, A.; Löhner, H.; Martinez-Garcia, G.; Ostendorf, R. W.; Schutz, Y.; Tlusty, P.; Turrisi, R.; Wagner, V.; Wilschut, H. W.
Differential cross sections of neutral pions emitted in (181)Ta+(197)Au collisions at a beam energy of 39.5A Me V have been measured with the two-arm photon spectrometer (TAPS). The kinetic energy and transverse momentum spectra of neutral pions cannot be properly described in the framework of the
Multiplicity correlations of intermediate-mass fragments with pions and fast protons in 12C + 197AU
International Nuclear Information System (INIS)
Turzo, K.; Begemann-Blaich, M.L.; Auger, G.
2003-12-01
Low-energy π + (E π 12 C+ 197 Au collisions at incident energies from 300 to 1800 MeV per nucleon were detected with the Si-Si(Li)-CsI(Tl) calibration telescopes of the INDRA multidetector. The inclusive angular distributions are approximately isotropic, consistent with multiple rescattering in the target spectator. The multiplicity correlations of the low-energy pions and of energetic protons (E p >or ≤ 150 MeV) with intermediate-mass fragments were determined from the measured coincidence data. The deduced correlation functions 1 + R ∼ 1.3 for inclusive event samples reflect the strong correlations evident from the common impact-parameter dependence of the considered multiplicities. For narrow impact-parameter bins (based on charged-particle multiplicity), the correlation functions are close to unity and do not indicate strong additional correlations. Only for pions at high particle multiplicities (central collisions) a weak anticorrelation is observed, probably due to a limited competition between these emissions. Overall, the results are consistent with the equilibrium assumption made in statistical multifragmentation scenarios. Predictions obtained with intranuclear cascade models coupled to the statistical multifragmentation model are in good agreement with the experimental data. (orig.)
Charge-odd and single-spin effects in two pion production in ep bar collisions
International Nuclear Information System (INIS)
Galynskij, M.V.; Kuraev, E.A.; Shajkhatdenov, B.G.; Ratcliffe, P.G.
2000-01-01
We consider two-photon and Bremsstrahlung mechanisms for the production of two charged pions in high-energy electron (proton) scattering off a transversely polarised proton. Interference between the relevant amplitudes generates a charge-odd contribution to the cross section for the process. In a kinematics with a jet moving along electron spin-independent part may be used for determination of phase differences for pion-pion scattering in the states with orbital momentum 0 or 2 and 1 whereas in a kinematics with a jet moving along proton spin-dependent part may be used to explain the experimental data for single-spin correlations in the production of negatively charged pions. We also discuss the backgrounds and estimate the accuracy of the results at less than 10% level. In addition simplified formulae derived for specific kinematics, with small total transverse pion momentum, are given
Invariant potential for elastic pion--nucleus scattering. Technical report No. 75-075
International Nuclear Information System (INIS)
Cammarata, J.B.; Banerjee, M.K.
1975-04-01
From the Wick-Dyson expansion of the exact propagator of a pion in the presence of a nucleus an invariant potential for crossing symmetric, elastic pion-nucleus scattering is obtained in terms of a series of pion-nucleon diagrams. The Chew-Low theory is used to develop a model in which the most important class of diagrams is effectively summed. Included in this model is the Exclusion Principle restriction on the pion-bound nucleon interaction, the effects of the binding of nucleons, a kinematic transformation of energy from the lab to the πN center of mass frames, and the Fermi motion and recoil of the target nucleons. From a numerical study of the effects of these processes on the π- 12 C total cross section, the relative importance of each is determined. Other processes contributing to the elastic scattering of pions not included in the present model are also discussed. (9 figures) (U.S.)
In-medium effective chiral lagrangians and the pion mass in nuclear matter
International Nuclear Information System (INIS)
Wirzba, A.
1995-01-01
We argue that the effective pion mass in nuclear matter obtained from chiral effective lagrangians is unique and does not depend on off-mass-shell extensions of the pion fields as e.g. the PCAC choice. The effective pion mass in isospin symmetric nuclear matter is predicted to increase slightly with increasing nuclear density, whereas the effective time-like pion decay constant and the magnitude of the density-dependent quark condensate decrease appreciably. The in-medium Gell-Mann-Oakes-Renner relation as well as other in-medium identities are studied in addition. Finally, several constraints on effective lagrangians for the description of the pion propagation in isospin symmetric, isotropic and homogeneous nuclear matter are discussed. (orig.)
Neutral Pion Rejection at L2 using the CMS Endcap Preshower
Kyriakis, Aristotelis; Loukas, Demetrios; Mousa, Jehad; Seez, Christopher
1999-01-01
Applying a general Artificial Neural Network approach, we have examined the possibility of neutral pion rejection at the Level 2 Trigger stage ( L2) principally using information from the CMS Endcap Preshower. We have studied both pion/photon and pion/electron discrimination. For L2 the hope was to achieve some useful pion/electron discrimination for a high electron efficiency. For a single electron/photon efficiency of 95% the results show that no useful rejection of neutral pions against electrons/photons can be obtained using this algorithm alone, due to the presence of tracker material. If the efficiency is lowered or information from the tracker is available, the rejection can increase dramatically. This will be the case for off-line analyses.
Pion double charge exchange in the Δ33 resonance region
International Nuclear Information System (INIS)
Wirzba, A.; Toki, H.; Siciliano, E.R.; Johnson, M.B.; Gilman, R.
1989-01-01
We examine the model dependence and nuclear-structure sensitivity of several Δ 33 -dominated processes contributing to pion double charge exchange on nuclei in the region of the Δ 33 resonance. These processes include the Δ 33 -nucleon interaction V NΔ and sequential scattering, in which the pion undergoes single charge exchange on two different nucleons. In all cases, the scattering takes place through the exchange of an intermediate π and ρ meson. Sequential-mediated double charge exchange is found to be only moderately sensitive to short-range correlations, meson-nucleon form factors, and the rho meson, whereas V NΔ -mediated double charge exchange is very sensitive to all these effects. Results are given for double charge exchange on 18 O (double isobaric analog transitions) and 16 O (nonanalog transitions). Sequential double charge exchange is shown to favor non-spin-flip matrix elements of the transition operator whereas V NΔ -mediated double charge exchange favors spin-flip matrix elements. The energy dependence of the zero-degree cross sections for V NΔ and sequential scattering are also different: Sequential tends to increase monotonically from 100 to 300 MeV, whereas V NΔ peaks at about 150 MeV. The delta-nucleon interaction is found likely to dominate over sequential scattering in nonanalog double charge exchange. The V NΔ is also large in analog double charge exchange, but it does not enable us to explain the anomalous behavior of the 18 O differential cross sections
Investigation of the radiation damage of GaAs detectors by protons, pions and neutrons
Energy Technology Data Exchange (ETDEWEB)
Luebelsmeyer, K. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Arbabi, S. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Braunschweig, W. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Chu, Z. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Krais, R. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Kubicki, T. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Rente, C. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Syben, O. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Tenbusch, F. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Toporowski, M. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Wittmer, B. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Xiao, W.J. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.
1997-05-01
Surface barrier detectors processed in Aachen using semi-insulating (SI) GaAs from several manufacturers have been irradiated with high fluences of neutrons (mean energy 1 MeV, fluence up to {Phi}{sub n} {proportional_to} 5 x 10{sup 14} cm{sup -2}), pions (191 MeV, fluence up to {Phi}{sub {pi}} {proportional_to} 0.6 x 10{sup 14} cm{sup -2}) and protons (23 GeV, fluence up to {Phi}{sub p} {proportional_to} 2 x 10{sup 14} cm{sup -2}). The detectors have been characterized in terms of macroscopic quantities like I-V characteristic curves and charge collection efficiencies for incident minimum ionizing- (mip) as well as {alpha}-particles. All detectors work well after the exposure. At the highest fluences a sizable degradation in the charge collection efficiencies has been observed for all investigated materials. SI-GaAs material with low carbon (LC) content seems to be less affected than substrates with a higher carbon concentration. At the highest irradiation level the mip signal from a 250 {mu}m thick detector made of LC material amounts to 8000 electrons (at 400 V bias voltage) independent of peaking times between 40 ns and 2.2 {mu}s. The leakage currents for this material are even reduced after the irradiation. (orig.).
Investigation of the radiation damage of GaAs detectors by protons, pions and neutrons
Energy Technology Data Exchange (ETDEWEB)
Tenbusch, F. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Arbabi, S. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Braunschweig, W. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Chu, Z. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Krais, R. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Kubicki, T. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Luebelsmeyer, K. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Rente, C. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Syben, O. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Toporowski, M. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Wittmer, B. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Xiao, W.J. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.
1997-04-01
Surface barrier detectors processed in Aachen using SI-GaAs from several manufacturers have been irradiated with high fluences of neutrons (mean energy 1 MeV, fluence up to {Phi}{sub n}{proportional_to}5 x 10{sup 14} cm{sup -2}), pions (191 MeV, fluence up to {Phi}{sub {pi}}{proportional_to}0.6 x 10{sup 14} cm{sup -2}) and protons (23 GeV, fluence up to {Phi}{sub p}{proportional_to}2 x 10{sup 14} cm{sup -2}). The detectors have been characterized in terms of macroscopic quantities like I-V characteristic curves and charge collection efficiencies for incident minimum ionizing- (mip) as well as {alpha}-particles. All detectors work well after the exposure. At the highest fluences a sizable degradation concerning the charge collection efficiencies has been observed for all investigated materials. SI-GaAs material with low carbon content (LC material from FCM, Freiberg) seems to be less affected than substrates with a higher carbon concentration. At the highest irradiation level the mip signal from a 250 {mu}m thick detector made of LC material amounts to 8000 electrons (at 400 V bias voltage) independent of peaking times between 40 ns and 2.2 {mu}s. The leakage currents for this material are even reduced after the irradiation. (orig.).
The pion polarisability and more measurements on chiral dynamics at COMPASS
Friedrich, Jan
2016-01-01
Within the physics program of the COMPASS experiment at CERN pion-photon reactions are measured via the Primakoff effect, referring to processes in which high-energetic pions react with the quasi-real photon field that surrounds the target nuclei. The production of a single hard photon in such a pion scattering at lowest momentum transfer to the nucleus is related to pion Compton scattering. From the measured cross-section shape, the pion polarisability has been determined, a result that has been published meanwhile as a Physical Review Letter [ 1 ]. The COMPASS measurement is in tension with the earlier dedicated measurements, and rather in agreement with the theoretical expectation from chiral perturbation theory. The analysis of a more recent high-statistics data taking is underway. Reactions with neutral and more charged pions in the final state are measured and analyzed as well. At low energy in the pion-photon centre-of-momentum system, these reactions are governed by chiral dynamics and contain informa...
The intercomparison of the dose distributions between conformation techniques with pions and photons
International Nuclear Information System (INIS)
Karasawa, K.; Nakagawa, K.; Akanuma, A.
1990-01-01
To compare conformation radiation treatment with pions vs photons, dose volume histograms (DVH) to the critical organs, including the spinal cord, kidney, and intestine, were examined in a patient with retroperitoneal soft tissue sarcoma. For photon conformation treatment, the following techniques were used: 360 degree rotation conformation technique (photon conformation), 4 fixed field technique (photon 4-field), and 2-axis conformation technique (photon 2-axial conformation). According to the DVH reduction method, complication probability was estimated. The concave portion of the target was conformed by pion conformation treatment, but not by photon conformation treatment. Pion conformation for the intestine showed the best DVH, whereas photon 4-field technique showed the worst DVH. For the kidney, pion conformation showed better DVH as compared with any other photon conformation treatment technique. In the spinal cord, photon 2-axial conformation was far superior, followed by pion conformation and then photon conformation and 4-field technique. A 2-axial technique showed a bigger inhomogeneity inside the target volume which is critical in curative treatment. TD 50 was 72 Gy for pion conformation, 53 Gy for photon conformation, 51 Gy for photon 4-field, and 68 Gy for photon 2-axial conformation. Complication probabilities for these conformation techniques at 60 Gy were 3%, 85%, 97%, and 9%. In view of tumor control probabilities, pion seems to have the biggest therapeutic ratio among these techniques. (N.K.)
Measurement of neutral current coherent neutral pion production on carbon in a few-GeV neutrino beam
International Nuclear Information System (INIS)
2010-01-01
The SciBooNE Collaboration reports a measurement of neutral current coherent neutral pion production on carbon by a muon neutrino beam with average energy 0.8 GeV. The separation of coherent from inclusive neutral pion production has been improved by detecting recoil protons from resonant neutral pion production. We measure the ratio of the neutral current coherent neutral pion production to total charged current cross sections to be (1.16 +/- 0.24) x 10-2. The ratio of charged current coherent pion to neutral current coherent pion production is calculated to be 0.14+0.30 -0.28, using our published charged current coherent pion measurement.
Structure of /sup 13/C studied by pion scattering near the (3,3) resonance
Energy Technology Data Exchange (ETDEWEB)
Seestrom-Morris, S.J.
1981-09-01
Good resolution (..pi../sup +/,..pi../sup +/') and (..pi../sup -/,..pi../sup -/') data were obtained for many states in /sup 13/C using the Energetic Pion Channel and Spectrometer at the Los Alamos Meson Physics Facility. Differential cross sections were measured for angles between 20/sup 0/ and 105/sup 0/ at an incident pion energy of 162 MeV for the elastic scattering as well as for states at excitation energies of 3.09, 3.68, 3.85, 7.55, 8.86, 9.5, 11.82, 16.05, 17.92, 21.37, and 21.6 MeV. Excitation functions were measured at momentum transfers of q = 1.1 h fm /sup -1/ and q = 1.4 h fm/sup -1/, for energies between 100 and 300 MeV. A sigma(..pi../sup -/)/sigma(..pi../sup +/) ratio of 9:1 was observed for the first time, indicating a pure neutron particle-hole excitation of a high spin state (J/sup ..pi../ = 9/2/sup +/). Strikingly different energy dependences were found for ..delta..S = 0 and ..delta..S = 1 transitions. Data for all states were compared with the microscopic model calculations of Lee and Kurath. Very good agreement was found between experiment and theory for the strongly excited states and the 9/2/sup +/ state at 9.5 MeV, in sharp contrast to the disagreement for weak transitions. The excitation function data and comparisons with the microscopic model calculations were used to identify the states at 16.05, 17.92, 21.37, and 21.6 MeV as either 7/2/sup +/ or 9/2/sup +/ states. The elastic scattering data were analyzed with an optical modeland the results were found to be consistent with neutron and proton distributions having equal rms radii. The optical potentials generated were used in a collective model analysis of the 3/2/sup -/ (3.68 MeV) and 5/2/sup -/ (7.55 MeV) states. The reduced transition probabilities (B(E2)) derived from the proton parts of the transition strength are in agreement with those determined from electromagnetic measurements.
Lattice study of the Boer-Mulders transverse momentum distribution in the pion
Energy Technology Data Exchange (ETDEWEB)
Engelhardt, Michael; Musch, Bernhard; Haegler, Philipp; Negele, John; Schaefer, Andreas
2014-11-01
The Boer-Mulders transverse momentum-dependent parton distribution (TMD) characterizes polarized quark transverse momentum in an unpolarized hadron. Techniques previously developed for lattice calculations of nucleon TMDs are applied to the pion. These techniques are based on the evaluation of matrix elements of quark bilocal operators containing a staple-shaped Wilson connection. Results for the Boer-Mulders transverse momentum shift in the pion, obtained at a pion mass of mπ=518MeV, are presented and compared to corresponding results in the nucleon.
Neutral pion production in the 16O+27Al reaction at 94 MeV/nucleon
International Nuclear Information System (INIS)
Badala, A.; Barbera, R.; Palmeri, A.; Pappalardo, G.S.; Riggi, F.; Russo, A.C.; Agodi, C.; Alba, R.; Bellia, G.; Coniglione, R.; Del Zoppo, A.; Finocchiaro, P.; Maiolino, C.; Migneco, E.; Piattelli, P.; Russo, G.; Sapienza, P.; Peghaire, A.
1993-01-01
The production of neutral pions in the reaction 16 O+ 27 Al at 94 MeV/nucleon was studied with a multidetector, which includes 180 BaF 2 modules. Kinetic energy spectra for several laboratory angles were measured. The total cross section for neutral pion production was deduced. Results were compared with previous findings on charged pions from the same reaction at the same energy and with the prediction of a dynamical model based on the numerical solution of the Boltzmann-Nordheim-Vlasov equation
Thermodynamics of pion gas using states predicted from {kappa}-deformed Poincare algebra
Energy Technology Data Exchange (ETDEWEB)
Cordeiro, Claudete E.; Delfino, Antonio; Dey, Jishnu
1995-02-17
K-deformed Poincare algebra, which preserves rotational and translational symmetries, can successfully predict the angular and radial excited states of the pion. At high temperature, T these states can be excited in the pion gas, in addition to the usual momentum excitation. We exploit this to look at pion free energy finding it increases linearly with T. The energy per particle and the entropy show evidence of a smooth phase transition after T=0.2 GeV. (author) 18 refs., 5 figs., 2 tabs.; e-mail: gfijdey at vmhpo.uff.br
Backward asymmetry measurements in the elastic pion-proton scattering at resonance energies
Alekseev, I. G.; Bazhanov, N. A.; Beloglazov, Yu. A.; Budkovsky, P. E.; Bunyatova, E. I.; Filimonov, E. A.; Kanavets, V. P.; Kovalev, A. I.; Koroleva, L. I.; Morozov, B. V.; Nesterov, V. M.; Novinsky, D. V.; Ryltsov, V. V.; Shchedrov, V. A.; Sulimov, A. D.
2008-01-01
The asymmetry parameter P was measured for the elastic pion-proton scattering in the very backward angular region of theta_cm ~ 150-170^o at several pion beam energies in the invariant mass range containing most of the pion-proton resonances. The general goal of the experimental program was to provide new data for partial wave analyses in order to resolve their uncertainties in the baryon resonance region to allow the unambiguous baryon spectrum reconstructions. Until recently the parameter P...
Determination of the negatively charged pion-proton scattering length from pionic hydrogen
Ericson, Torleif Eric Oskar; Wycech, S
2003-01-01
We derive a closed, model independent, expression for the electromagnetic correction factor to the hadronic scattering length extracted from a hydrogenic atom with an extended charge and in the limit of a short ranged hadronic interaction to terms of order ((alpha)**2)(log(alpha)) in the limit of a non-relativistic approach. A hadronic negatively charged pion-proton scattering length of 0.0870(5), in units of inverse charged pion-mass, is deduced, leading to a pion-nucleon coupling constant from the GMO relation equals to 14.00(19).
Beam energy and centrality dependence of two-pion Bose-Einstein correlations at SPS energies
Energy Technology Data Exchange (ETDEWEB)
Adamova, D.; Agakichiev, G.; Appelshaeuser, H. E-mail: appels@physi.uni-heidelberg.de; Belaga, V.; Braun-Munzinger, P.; Campagnolo, R.; Castillo, A.; Cherlin, A.; Damjanovic, S.; Dietel, T.; Dietrich, L.; Drees, A.; Esumi, S.I.; Filimonov, K.; Fomenko, K.; Fraenkel, Z.; Garabatos, C.; Glaessel, P.; Hering, G.; Holeczek, J.; Kushpil, V.; Lenkeit, B.; Ludolphs, W.; Maas, A.; Marin, A.; Milosevic, J.; Milov, A.; Miskowiec, D.; Musa, L.; Panebrattsev, Yu.; Petchenova, O.; Petracek, V.; Pfeiffer, A.; Rak, J.; Ravinovich, I.; Rehak, P.; Richter, M.; Sako, H.; Schmitz, W.; Schukraft, J.; Sedykh, S.; Seipp, W.; Sharma, A.; Shimansky, S.; Slivova, J.; Specht, H.J.; Stachel, J.; Sumbera, M.; Tilsner, H.; Tserruya, I.; Wessels, J.P.; Wienold, T.; Windelband, B.; Wurm, J.P.; Xie, W.; Yurevich, S.; Yurevich, V.V
2003-02-10
Results are presented of a two-pion interferometry (HBT) analysis in Pb+Au collisions at 40, 80, and 158 A GeV. A detailed study of the Bertsch-Pratt HBT radius parameters has been performed as function of the mean pair transverse momentum k{sub t} and in bins of the centrality of the collision. From these results we extract model-dependent information about the space-time evolution of the reaction. An investigation of the effective volume of the pion emitting system provides an important tool to study the properties of thermal pion freeze-out.
Adolph, C; Alexeev, M G; Alexeev, G D; Amoroso, A; Andrieux, V; Anosov, V; Austregesilo, A; Badełek, B; Balestra, F; Barth, J; Baum, G; Beck, R; Bedfer, Y; Berlin, A; Bernhard, J; Bicker, K; Bieling, J; Birsa, R; Bisplinghoff, J; Bodlak, M; Boer, M; Bordalo, P; Bradamante, F; Braun, C; Bressan, A; Büchele, M; Burtin, E; Capozza, L; Chiosso, M; Chung, S U; Cicuttin, A; Crespo, M L; Curiel, Q; Dalla Torre, S; Dasgupta, S S; Dasgupta, S; Denisov, O Yu; Donskov, S V; Doshita, N; Duic, V; Dünnweber, W; Dziewiecki, M; Efremov, A; Elia, C; Eversheim, P D; Eyrich, W; Faessler, M; Ferrero, A; Filin, A; Finger, M; Finger jr , M; Fischer, H; Franco, C; du Fresne von Hohenesche, N; Friedrich, J M; Frolov, V; Gautheron, F; Gavrichtchouk, O P; Gerassimov, S; Geyer, R; Gnesi, I; Gobbo, B; Goertz, S; Gorzellik, M; Grabmüller, S; Grasso, A; Grube, B; Grussenmeyer, T; Guskov, A; Guthörl, T; Haas, F; von Harrach, D; Hahne, D; Hashimoto, R; Heinsius, F H; Herrmann, F; Hinterberger, F; Höppner, Ch; Horikawa, N; d’Hose, N; Huber, S; Ishimoto, S; Ivanov, A; Ivanshin, Yu; Iwata, T; Jahn, R; Jary, V; Jasinski, P; Jörg, P; Joosten, R; Kabuß, E; Ketzer, B; Khaustov, G V; Khokhlov, Yu A; Kisselev, Yu; Klein, F; Klimaszewski, K; Koivuniemi, J H; Kolosov, V N; Kondo, K; Königsmann, K; Konorov, I; Konstantinov, V F; Kotzinian, A M; Kouznetsov, O; Krämer, M; Kroumchtein, Z V; Kuchinski, N; Kunne, F; Kurek, K; Kurjata, R P; Lednev, A A; Lehmann, A; Levillain, M; Levorato, S; Lichtenstadt, J; Maggiora, A; Magnon, A; Makke, N; Mallot, G K; Marchand, C; Martin, A; Marzec, J; Matousek, J; Matsuda, H; Matsuda, T; Meshcheryakov, G; Meyer, W; Michigami, T; Mikhailov, Yu V; Miyachi, Y; Nagaytsev, A; Nagel, T; Nerling, F; Neubert, S; Neyret, D; Nikolaenko, V I; Novy, J; Nowak, W -D; Nunes, A S; Olshevsky, A G; Orlov, I; Ostrick, M; Panknin, R; Panzieri, D; Parsamyan, B; Paul, S; Peshekhonov, D V; Platchkov, S; Pochodzalla, J; Polyakov, V A; Pretz, J; Quaresma, M; Quintans, C; Ramos, S; Regali, C; Reicherz, G; Rocco, E; Rossiyskaya, N S; Ryabchikov, D I; Rychter, A; Samoylenko, V D; Sandacz, A; Sarkar, S; Savin, I A; Sbrizzai, G; Schiavon, P; Schill, C; Schlüter, T; Schmidt, K; Schmieden, H; Schönning, K; Schopferer, S; Schott, M; Shevchenko, O Yu; Silva, L; Sinha, L; Sirtl, S; Slunecka, M; Sosio, S; Sozzi, F; Srnka, A; Steiger, L; Stolarski, M; Sulc, M; Sulej, R; Suzuki, H; Szabelski, A; Szameitat, T; Sznajder, P; Takekawa, S; ter Wolbeek, J; Tessaro, S; Tessarotto, F; Thibaud, F; Uhl, S; Uman, I; Virius, M; Wang, L; Weisrock, T; Wilfert, M; Windmolders, R; Wollny, H; Zaremba, K; Zavertyaev, M; Zemlyanichkina, E; Ziembicki, M; Zink, A
2015-01-01
Measurements of the Collins and Sivers asymmetries for charged pions and charged and neutral kaons produced in semi-inclusive deep-inelastic scattering of high energy muons off transversely polarised protons are presented. The results were obtained using all the available COMPASS proton data, which were taken in the years 2007 and 2010. The Collins asymmetries exhibit in the valence region a non-zero signal for pions and there are hints of non-zero signal also for kaons. The Sivers asymmetries are found to be positive for positive pions and kaons and compatible with zero otherwise.
SiPM-based veto detector for the pion beam at FOPI
Energy Technology Data Exchange (ETDEWEB)
Ahmed, Gamal, E-mail: gsmoawad@hotmail.com; Buehler, Pual; Hartmann, Olaf; Marton, Johann; Suzuki, Ken; Zmeskal, Johann [Stefan Meyer Institute for Subatomic Physics of the Austrian Academy of Sciences (Austria)
2012-05-15
Recently the FOPI collaboration carried out an experiment to study the in medium properties of the K{sup + }K{sup - } system by using the pion beam interactions at 1.7 GeV/c. The experiment with a pion beam poses specific requirements to the detectors and therefore the original FOPI setup needed modifications. The new hardware developments for this experiment include the replacement of the veto detector with another more compact design. Within this report we describe the design and results of a test measurement of the new FOPI veto detector system with the pion beam.
Directory of Open Access Journals (Sweden)
C. Adolph
2015-05-01
Full Text Available Measurements of the Collins and Sivers asymmetries for charged pions and charged and neutral kaons produced in semi-inclusive deep-inelastic scattering of high energy muons off transversely polarised protons are presented. The results were obtained using all the available COMPASS proton data, which were taken in the years 2007 and 2010. The Collins asymmetries exhibit in the valence region a non-zero signal for pions and there are hints of non-zero signal also for kaons. The Sivers asymmetries are found to be positive for positive pions and kaons and compatible with zero otherwise.
Bose-Einstein Correlations of Neutral and Charged Pions in Hadronic Z Decays
Achard, P.; Aguilar-Benitez, M.; Alcaraz, J.; Alemanni, G.; Allaby, J.; Aloisio, A.; Alviggi, M.G.; Anderhub, H.; Andreev, Valery P.; Anselmo, F.; Arefev, A.; Azemoon, T.; Aziz, T.; Baarmand, M.; Bagnaia, P.; Bajo, A.; Baksay, G.; Baksay, L.; Baldew, S.V.; Banerjee, S.; Banerjee, Sw.; Barczyk, A.; Barillere, R.; Bartalini, P.; Basile, M.; Batalova, N.; Battiston, R.; Bay, A.; Becattini, F.; Becker, U.; Behner, F.; Bellucci, L.; Berbeco, R.; Berdugo, J.; Berges, P.; Bertucci, B.; Betev, B.L.; Biasini, M.; Biglietti, M.; Biland, A.; Blaising, J.J.; Blyth, S.C.; Bobbink, G.J.; Bohm, A.; Boldizsar, L.; Borgia, B.; Bottai, S.; Bourilkov, D.; Bourquin, M.; Braccini, S.; Branson, J.G.; Brochu, F.; Buijs, A.; Burger, J.D.; Burger, W.J.; Cai, X.D.; Capell, M.; Cara Romeo, G.; Carlino, G.; Cartacci, A.; Casaus, J.; Cavallari, F.; Cavallo, N.; Cecchi, C.; Cerrada, M.; Chamizo, M.; Chang, Y.H.; Chemarin, M.; Chen, A.; Chen, G.; Chen, G.M.; Chen, H.F.; Chen, H.S.; Chiefari, G.; Cifarelli, L.; Cindolo, F.; Clare, I.; Clare, R.; Coignet, G.; Colino, N.; Costantini, S.; de la Cruz, B.; Cucciarelli, S.; Dai, T.S.; van Dalen, J.A.; de Asmundis, R.; Deglon, P.; Debreczeni, J.; Degre, A.; Deiters, K.; della Volpe, D.; Delmeire, E.; Denes, P.; DeNotaristefani, F.; De Salvo, A.; Diemoz, M.; Dierckxsens, M.; van Dierendonck, D.; Dionisi, C.; Dittmar, M.; Doria, A.; Dova, M.T.; Duchesneau, D.; Duinker, P.; Echenard, B.; Eline, A.; El Mamouni, H.; Engler, A.; Eppling, F.J.; Ewers, A.; Extermann, P.; Falagan, M.A.; Falciano, S.; Favara, A.; Fay, J.; Fedin, O.; Felcini, M.; Ferguson, T.; Fesefeldt, H.; Fiandrini, E.; Field, J.H.; Filthaut, F.; Fisher, P.H.; Fisher, W.; Fisk, I.; Forconi, G.; Freudenreich, K.; Furetta, C.; Galaktionov, Iouri; Ganguli, S.N.; Garcia-Abia, Pablo; Gataullin, M.; Gentile, S.; Giagu, S.; Gong, Z.F.; Grenier, Gerald Jean; Grimm, O.; Gruenewald, M.W.; Guida, M.; van Gulik, R.; Gupta, V.K.; Gurtu, A.; Gutay, L.J.; Haas, D.; Hatzifotiadou, D.; Hebbeker, T.; Herve, Alain; Hirschfelder, J.; Hofer, H.; Holzner, G.; Hou, S.R.; Hu, Y.; Jin, B.N.; Jones, Lawrence W.; de Jong, P.; Josa-Mutuberria, I.; Kafer, D.; Kaur, M.; Kienzle-Focacci, M.N.; Kim, J.K.; Kirkby, Jasper; Kittel, W.; Klimentov, A.; Konig, A.C.; Kopal, M.; Koutsenko, V.; Kraber, M.; Kraemer, R.W.; Krenz, W.; Kruger, A.; Kunin, A.; Ladron de Guevara, P.; Laktineh, I.; Landi, G.; Lebeau, M.; Lebedev, A.; Lebrun, P.; Lecomte, P.; Lecoq, P.; Le Coultre, P.; Lee, H.J.; Le Goff, J.M.; Leiste, R.; Levtchenko, P.; Li, C.; Likhoded, S.; Lin, C.H.; Lin, W.T.; Linde, F.L.; Lista, L.; Liu, Z.A.; Lohmann, W.; Longo, E.; Lu, Y.S.; Lubelsmeyer, K.; Luci, C.; Luckey, David; Luminari, L.; Lustermann, W.; Ma, W.G.; Malgeri, L.; Malinin, A.; Mana, C.; Mangeol, D.; Mans, J.; Martin, J.P.; Marzano, F.; Mazumdar, K.; McNeil, R.R.; Mele, S.; Merola, L.; Meschini, M.; Metzger, W.J.; Mihul, A.; Milcent, H.; Mirabelli, G.; Mnich, J.; Mohanty, G.B.; Muanza, G.S.; Muijs, A.J.M.; Musicar, B.; Musy, M.; Nagy, S.; Napolitano, M.; Nessi-Tedaldi, F.; Newman, H.; Niessen, T.; Nisati, A.; Kluge, Hannelies; Ofierzynski, R.; Organtini, G.; Palomares, C.; Pandoulas, D.; Paolucci, P.; Paramatti, R.; Passaleva, G.; Patricelli, S.; Paul, Thomas Cantzon; Pauluzzi, M.; Paus, C.; Pauss, F.; Pedace, M.; Pensotti, S.; Perret-Gallix, D.; Petersen, B.; Piccolo, D.; Pierella, F.; Pioppi, M.; Piroue, P.A.; Pistolesi, E.; Plyaskin, V.; Pohl, M.; Pojidaev, V.; Postema, H.; Pothier, J.; Prokofev, D.O.; Prokofiev, D.; Quartieri, J.; Rahal-Callot, G.; Rahaman, M.A.; Raics, P.; Raja, N.; Ramelli, R.; Rancoita, P.G.; Ranieri, R.; Raspereza, A.; Razis, P.; Ren, D.; Rescigno, M.; Reucroft, S.; Riemann, S.; Riles, Keith; Roe, B.P.; Romero, L.; Rosca, A.; Rosier-Lees, S.; Roth, Stefan; Rosenbleck, C.; Roux, B.; Rubio, J.A.; Ruggiero, G.; Rykaczewski, H.; Sakharov, A.; Saremi, S.; Sarkar, S.; Salicio, J.; Sanchez, E.; Sanders, M.P.; Schafer, C.; Schegelsky, V.; Schmidt-Kaerst, S.; Schmitz, D.; Schopper, H.; Schotanus, D.J.; Schwering, G.; Sciacca, C.; Servoli, L.; Shevchenko, S.; Shivarov, N.; Shoutko, V.; Shumilov, E.; Shvorob, A.; Siedenburg, T.; Son, D.; Spillantini, P.; Steuer, M.; Stickland, D.P.; Stoyanov, B.; Straessner, A.; Sudhakar, K.; Sultanov, G.; Sun, L.Z.; Sushkov, S.; Suter, H.; Swain, J.D.; Szillasi, Z.; Tang, X.W.; Tarjan, P.; Tauscher, L.; Taylor, L.; Tellili, B.; Teyssier, D.; Timmermans, Charles; Ting, Samuel C.C.; Ting, S.M.; Tonwar, S.C.; Toth, J.; Tully, C.; Tung, K.L.; Uchida, Y.; Ulbricht, J.; Valente, E.; Van de Walle, R.T.; Veszpremi, V.; Vesztergombi, G.; Vetlitsky, I.; Vicinanza, D.; Viertel, G.; Villa, S.; Vivargent, M.; Vlachos, S.; Vodopianov, I.; Vogel, H.; Vogt, H.; Vorobev, I.; Vorobyov, A.A.; Wadhwa, M.; Wallraff, W.; Wang, M.; Wang, X.L.; Wang, Z.M.; Weber, M.; Wienemann, P.; Wilkens, H.; Wu, S.X.; Wynhoff, S.; Xia, L.; Xu, Z.Z.; Yamamoto, J.; Yang, B.Z.; Yang, C.G.; Yang, H.J.; Yang, M.; Yeh, S.C.; Zalite, A.; Zalite, Yu.; Zhang, Z.P.; Zhao, J.; Zhu, G.Y.; Zhu, R.Y.; Zhuang, H.L.; Zichichi, A.; Zilizi, G.; Zimmermann, B.; Zoller, M.
2002-01-01
Bose-Einstein correlations of both neutral and like-sign charged pion pairs are measured in a sample of 2 million hadronic $\\mathrm{Z}$ decays collected with the L3 detector at LEP. The analysis is performed in the four-momentum difference range $300 \\mathrm{\\ Me\\kern -0.1em V} < Q < 2 \\mathrm{\\ Ge\\kern -0.1em V}$. The radius of the neutral pion source is found to be smaller than that of charged pions. This result is in qualitative agreement with the string fragmentation model. \\end{document}
Superluminal neutrinos at OPERA confront pion decay kinematics.
Cowsik, Ramanath; Nussinov, Shmuel; Sarkar, Utpal
2011-12-16
Violation of Lorentz invariance (VLI) has been suggested as an explanation of the superluminal velocities of muon neutrinos reported by OPERA. In this Letter, we show that the amount of VLI required to explain this result poses severe difficulties with the kinematics of the pion decay, extending its lifetime and reducing the momentum carried away by the neutrinos. We show that the OPERA experiment limits α=(ν(ν)-c)/c<4×10(-6). We then take recourse to cosmic-ray data on the spectrum of muons and neutrinos generated in Earth's atmosphere to provide a stronger bound on VLI: (ν-c)/c<10(-12). © 2011 American Physical Society
Measurement of Charged Pions from Neutrino-produced Nuclear Resonance
Energy Technology Data Exchange (ETDEWEB)
Simon, Clifford N. [Univ. of California, Irvine, CA (United States)
2014-01-01
A method for identifying stopped pions in a high-resolution scintillator bar detector is presented. I apply my technique to measure the axial mass M^{Δ}_{A}for production of the Δ(1232) resonance by neutrino, with the result M^{Δ}_{A} = 1.16±0.20 GeV (68% CL) (limited by statistics). The result is produced from the measured spectrum of reconstructed momentum-transfer Q^{2}. I proceed by varying the value of M^{Δ}_{A} in a Rein-Sehgal-based Monte Carlo to produce the best agreement, using shape only (not normalization). The consistency of this result with recent reanalyses of previous bubble-chamber experiments is discussed.
Inclusive Production of Neutral Pions in Hadronic Z Decays
Barate, R; Décamp, D; Ghez, P; Goy, C; Lees, J P; Lucotte, A; Minard, M N; Nief, J Y; Odier, P; Pietrzyk, B; Casado, M P; Chmeissani, M; Comas, P; Crespo, J M; Delfino, M C; Fernández, E; Fernández-Bosman, M; Garrido, L; Juste, A; Martínez, M; Orteu, S; Padilla, C; Park, I C; Pascual, A; Perlas, J A; Riu, I; Sánchez, F; Teubert, F; Colaleo, A; Creanza, D; De Palma, M; Gelao, G; Girone, M; Iaselli, Giuseppe; Maggi, G; Maggi, M; Marinelli, N; Nuzzo, S; Ranieri, A; Raso, G; Ruggieri, F; Selvaggi, G; Silvestris, L; Tempesta, P; Tricomi, A; Zito, G; Huang, X; Lin, J; Ouyang, Q; Wang, T; Xie, Y; Xu, R; Xue, S; Zhang, J; Zhang, L; Zhao, W; Abbaneo, D; Alemany, R; Bazarko, A O; Bright-Thomas, P G; Cattaneo, M; Cerutti, F; Coyle, P; Drevermann, H; Forty, Roger W; Frank, M; Hagelberg, R; Harvey, J; Janot, P; Jost, B; Kneringer, E; Knobloch, J; Lehraus, Ivan; Lutters, G; Mato, P; Minten, Adolf G; Miquel, R; Mir, L M; Moneta, L; Oest, T; Pacheco, A; Pusztaszeri, J F; Ranjard, F; Rensing, P E; Rizzo, G; Rolandi, Luigi; Schlatter, W D; Schmelling, M; Schmitt, M; Schneider, O; Tejessy, W; Tomalin, I R; Venturi, A; Wachsmuth, H W; Wagner, A; Ajaltouni, Ziad J; Barrès, A; Boyer, C; Falvard, A; Gay, P; Guicheney, C; Henrard, P; Jousset, J; Michel, B; Monteil, S; Montret, J C; Pallin, D; Perret, P; Podlyski, F; Proriol, J; Rosnet, P; Rossignol, J M; Fearnley, Tom; Hansen, J B; Hansen, J D; Hansen, J R; Hansen, P H; Nilsson, B S; Rensch, B; Wäänänen, A; Daskalakis, G; Kyriakis, A; Markou, C; Simopoulou, Errietta; Siotis, I; Vayaki, Anna; Zachariadou, K; Blondel, A; Bonneaud, G R; Brient, J C; Bourdon, P; Rougé, A; Rumpf, M; Valassi, Andrea; Verderi, M; Videau, H L; Candlin, D J; Parsons, M I; Focardi, E; Parrini, G; Corden, M; Georgiopoulos, C H; Jaffe, D E; Antonelli, A; Bencivenni, G; Bologna, G; Bossi, F; Campana, P; Capon, G; Casper, David William; Chiarella, V; Felici, G; Laurelli, P; Mannocchi, G; Murtas, F; Murtas, G P; Passalacqua, L; Pepé-Altarelli, M; Curtis, L; Dorris, S J; Halley, A W; Knowles, I G; Lynch, J G; O'Shea, V; Raine, C; Scarr, J M; Smith, K; Teixeira-Dias, P; Thompson, A S; Thomson, E; Thomson, F; Turnbull, R M; Becker, U; Geweniger, C; Graefe, G; Hanke, P; Hansper, G; Hepp, V; Kluge, E E; Putzer, A; Schmidt, M; Sommer, J; Stenzel, H; Tittel, K; Werner, S; Wunsch, M; Beuselinck, R; Binnie, David M; Cameron, W; Dornan, Peter J; Martin, E B; Moutoussi, A; Nash, J; Sedgbeer, J K; Stacey, A M; Williams, M D; Dissertori, G; Girtler, P; Kuhn, D; Rudolph, G; Betteridge, A P; Bowdery, C K; Colrain, P; Crawford, G; Finch, A J; Foster, F; Hughes, G; Sloan, Terence; Williams, M I; Galla, A; Giehl, I; Greene, A M; Hoffmann, C; Jakobs, K; Kleinknecht, K; Quast, G; Renk, B; Rohne, E; Sander, H G; Van Gemmeren, P; Zeitnitz, C; Aubert, Jean-Jacques; Benchouk, C; Bonissent, A; Bujosa, G; Calvet, D; Carr, J; Diaconu, C A; Etienne, F; Konstantinidis, N P; Leroy, O; Payre, P; Rousseau, D; Talby, M; Sadouki, A; Thulasidas, M; Trabelsi, K; Aleppo, M; Ragusa, F; Berlich, R; Blum, Walter; Büscher, V; Dietl, H; Dydak, Friedrich; Ganis, G; Gotzhein, C; Kroha, H; Lütjens, G; Lutz, Gerhard; Männer, W; Moser, H G; Richter, R H; Rosado-Schlosser, A; Schael, S; Settles, Ronald; Seywerd, H C J; Saint-Denis, R; Wiedenmann, W; Wolf, G; Boucrot, J; Callot, O; Chen, S; Choi, Y; Cordier, A; Davier, M; Duflot, L; Grivaz, J F; Heusse, P; Höcker, A; Jacholkowska, A; Jacquet, M; Kim, D W; Le Diberder, F R; Lefrançois, J; Lutz, A M; Nikolic, I A; Park, H J; Schune, M H; Simion, S; Veillet, J J; Videau, I; Zerwas, D; Azzurri, P; Bagliesi, G; Batignani, G; Bettarini, S; Bozzi, C; Calderini, G; Carpinelli, M; Ciocci, M A; Ciulli, V; Dell'Orso, R; Fantechi, R; Ferrante, I; Foà, L; Forti, F; Giassi, A; Giorgi, M A; Gregorio, A; Ligabue, F; Lusiani, A; Marrocchesi, P S; Messineo, A; Palla, Fabrizio; Sanguinetti, G; Sciabà, A; Spagnolo, P; Steinberger, Jack; Tenchini, Roberto; Tonelli, G; Vannini, C; Verdini, P G; Blair, G A; Bryant, L M; Chambers, J T; Gao, Y; Green, M G; Medcalf, T; Perrodo, P; Strong, J A; Von Wimmersperg-Töller, J H; Botterill, David R; Clifft, R W; Edgecock, T R; Haywood, S; Maley, P; Norton, P R; Thompson, J C; Wright, A E; Bloch-Devaux, B; Colas, P; Emery, S; Kozanecki, Witold; Lançon, E; Lemaire, M C; Locci, E; Pérez, P; Rander, J; Renardy, J F; Roussarie, A; Schuller, J P; Schwindling, J; Trabelsi, A; Vallage, B; Black, S N; Dann, J H; Johnson, R P; Kim, H Y; Litke, A M; McNeil, M A; Taylor, G; Booth, C N; Boswell, R; Brew, C A J; Cartwright, S L; Combley, F; Kelly, M S; Lehto, M H; Newton, W M; Reeve, J; Thompson, L F; Böhrer, A; Brandt, S; Cowan, G D; Grupen, Claus; Minguet-Rodríguez, J A; Rivera, F; Saraiva, P; Smolik, L; Stephan, F; Apollonio, M; Bosisio, L; Della Marina, R; Giannini, G; Gobbo, B; Musolino, G; Rothberg, J E; Wasserbaech, S R; Armstrong, S R; Elmer, P; Feng, Z; Ferguson, D P S; Gao, Y S; González, S; Grahl, J; Greening, T C; Hayes, O J; Hu, H; McNamara, P A; Nachtman, J M; Orejudos, W; Pan, Y B; Saadi, Y; Scott, I J; Walsh, J; Wu Sau Lan; Wu, X; Yamartino, J M; Zheng, M; Zobernig, G
1997-01-01
A measurement of the inclusive production of pi0 mesons in hadronic Z decays is presented and compared to Monte Carlo model predictions. The analysis is based on approximately 2 million hadronic events recorded with the ALEPH detector at LEP at a centre-of-mass energy of sqrt(s) = 91.2 GeV. Neutral pions are reconstructed using photons from conversion pairs and photons measured in the electromagnetic calorimeter. The inclusive pi0 momentum spectrum is measured in the range from 0.025 < x(p) = p/p(beam) < 1 to be 4.80 +/- 0.07(stat) +/- 0.31(sys). The differential inclusive pi0 cross section has also been measured as a function of transverse momentum with respect to the event plane (p_T^in and p_T^out_T).
Off-shell persistence of composite pions and kaons
Qin, Si-Xue; Chen, Chen; Mezrag, Cédric; Roberts, Craig D.
2018-01-01
In order for a Sullivan-like process to provide reliable access to a meson target as t becomes spacelike, the pole associated with that meson should remain the dominant feature of the quark-antiquark scattering matrix and the wave function describing the related correlation must evolve slowly and smoothly. Using continuum methods for the strong-interaction bound-state problem, we explore and delineate the circumstances under which these conditions are satisfied: for the pion, this requires -t ≲0.6 GeV2 , whereas -t ≲0.9 GeV2 will suffice for the kaon. These results should prove useful in planning and evaluating the potential of numerous experiments at existing and proposed facilities.
Charge ratio of cosmic pions in the atmosphere
Bhattacharya, D P; Sarkar, K
1977-01-01
The CERN intersecting storage ring data on pp to pi /sup +or-/+X inclusive reactions can be represented by a single scaling variable eta =2p/sub T//sup 2/x/(c ln(s/s/sub 0/)), for 0.075
Shear viscosity and entropy of a pion gas
Energy Technology Data Exchange (ETDEWEB)
Rose, Jean-Bernard; Oliinychenko, Dmytro; Schaefer, Anna; Petersen, Hannah [FIAS, Goethe University, Frankfurt (Germany)
2016-07-01
A model of microscopic non-equilibrium dynamics for classical point particles is used to calculate the transport coefficients of dense hadronic matter. Specifically, the shear viscosity to entropy density ratio is investigated, and the temperature dependence between 100 MeV and 300 MeV is explored. Calculations are made at corresponding particle densities going from 0.01 to 0.34 in a pion box simulating infinite matter. The results for the entropy and shear viscosity are then compared to analytic estimates. In addition, massless particles as well as ρ-meson resonance excitations are included. This will be the starting point for the calculation of more transport coefficients as functions of T and μ{sub B}; expanding systems could also be considered.
Pion production model - connection between dynamics and quark models
Energy Technology Data Exchange (ETDEWEB)
Lee, T.-S. H.; Sato, T.
2000-05-17
The authors discuss the difficulties in testing the hadron models by using the N{sup *} parameters extracted from the empirical amplitude analyses of the {pi}N and {gamma}N reaction data. As an alternative or perhaps a more advantageous approach, they present a Hamiltonian formulation that can relate the pion production dynamics and the constituent quark models of N{sup *} structure. The application of the approach in investigating the {Delta} and N{sup *}(S{sub 11}) excitations is reviewed. It is found that while the {Delta} excitation can be described satisfactory, the {pi}N scattering in S{sub 11} channel can not be described by the constituent quark models based on either the one-gluon-exchange or one-meson-exchange mechanisms. A phenomenological quark-quark potential has been constructed to reproduce the S{sub 11} amplitude.
Energy Technology Data Exchange (ETDEWEB)
Herdoiza, G
2004-04-15
The QCD non-perturbative effects are among the main sources of uncertainty in our present knowledge of the Standard Model phenomenology. I will present some of the methods which can be used to study these effects, and I will particularly treat the case of lattice QCD. Effective theories can be combined to the lattice approach in order to study the chiral and the heavy quark sectors. I will give some examples of how these properties can be successfully applied to the quark flavour phenomenology. The coupling of heavy mesons to the pion is related to a non-perturbative quantity, noted g-bar, which is required to extract physical results from the effective theory combining both chiral and heavy quark symmetry. This coupling is also involved in the study of the form factors appearing in the heavy to light semi-leptonic decays. These heavy meson decays are used to extract some of the CKM matrix elements which are know, up to now, only with large uncertainties. Moreover, the chiral effects of heavy mesons depend on pion loops whose vertices are precisely the coupling g-bar. These are some of the reasons why the theoretical and experimental determination of this coupling is required. I will present the results of its studies on the lattice and I will compare them to those obtained through several other methods. I will therefore describe these different approaches, their limitations and possible improvements, both from the point of view of the method and of its application to the determination of the coupling g-bar. (author)
New high precision data on the differential cross sections of the pion-proton elastic scattering
Directory of Open Access Journals (Sweden)
Alekseev I. G.
2014-01-01
Full Text Available The EPECUR collaboration presents new high precision data on the pion-proton elastic scattering in the second resonance region. The experiment EPECUR is placed on the universal beam channel of the accelerator ITEP. The setup features 0.1% beam pion momentum tagging system, 25 cm long liquid hydrogen target, placed in mylar container and beryllium outer shell, low material wire drift chambers and high performance DAQ. More than 3 billions of triggers have been collected. The data cover pion beam momentum range 0.8 - 1.3 GeV/c and 40-120 degrees center-of-mass scattering angle range for both positive and negative pions. The measured differential cross section has 2% statistical accuracy in 2 degrees angle and 5 MeV/c momentum intervals.
International Nuclear Information System (INIS)
Hung, P.Q.
1977-01-01
It is shown that by looking at data from neutrino-induced semi-inclusive pion and inclusive reactions on isoscalar targets along, one can determine completely the neutral current couplings. Predictions for various models are also presented. (Auth.)
Fermi motion versus co-operative effects in subthreshold pion and energetic gamma production
International Nuclear Information System (INIS)
Knoll, J.
1986-06-01
Various reaction mechanisms proposed to explain the production of pions at 'sub-threshold' energies and of energetic gammas are examined. They range from the nucleon-nucleon single collision mechanism to a co-operative multi-nucleon process. With a shell model prescription for the initial state energies the single collision picture cannot explain the data. The participation of many nucleons in the pion production process appears to be necessary. We present a statistical model which demands the co-operative action of several of the target and projectile nucleons in the pion production process. The formation of composite fragments alongside with the produced pion is seen to be vital to understand the experimental data within this model. (orig.)
Pion-nucleon scattering: from chiral perturbation theory to Roy-Steiner equations
Kubis, Bastian; Hoferichter, Martin; de Elvira, Jacobo Ruiz; Meißner, Ulf-G.
2016-11-01
Ever since Weinberg's seminal predictions of the pion-nucleon scattering amplitudes at threshold, this process has been of central interest for the study of chiral dynamics involving nucleons. The scattering lengths or the pion-nucleon σ-term are fundamental quantities characterizing the explicit breaking of chiral symmetry by means of the light quark masses. On the other hand, pion-nucleon dynamics also strongly affects the long-range part of nucleon-nucleon potentials, and hence has a far-reaching impact on nuclear physics. We discuss the fruitful combination of dispersion-theoretical methods, in the form of Roy-Steiner equations, with chiral dynamics to determine pion-nucleon scattering amplitudes at low energies with high precision.*
Minkowski space pion model inspired by lattice QCD running quark mass
Directory of Open Access Journals (Sweden)
Clayton S. Mello
2017-03-01
Full Text Available The pion structure in Minkowski space is described in terms of an analytic model of the Bethe–Salpeter amplitude combined with Euclidean Lattice QCD results. The model is physically motivated to take into account the running quark mass, which is fitted to Lattice QCD data. The pion pseudoscalar vertex is associated to the quark mass function, as dictated by dynamical chiral symmetry breaking requirements in the limit of vanishing current quark mass. The quark propagator is analyzed in terms of a spectral representation, and it shows a violation of the positivity constraints. The integral representation of the pion Bethe–Salpeter amplitude is also built. The pion space-like electromagnetic form factor is calculated with a quark electromagnetic current, which satisfies the Ward–Takahashi identity to ensure current conservation. The results for the form factor and weak decay constant are found to be consistent with the experimental data.
Voskresensky, D. N.; Kolomeitsev, E. E.
2017-12-01
We consider a hot isospin-symmetric pion gas with the dynamically fixed number of particles in the model with a λφ 4 interaction. In the thermodynamic limit, for temperature above the critical value for the Bose-Einstein condensation we calculate the effective pion mass, the chemical potential and the normalized variance. In contrast to the ideal gas, the normalized variance remains finite in the critical point of the Bose-Einstein condensation.
Extraction of the pion-nucleon sigma-term from the spectrum of exotic baryons
International Nuclear Information System (INIS)
Schweitzer, P.
2004-01-01
The pion-nucleon sigma-term is extracted on the basis of the soliton picture of the nucleon from the mass spectrum of usual and the recently observed exotic baryons, assuming that they have positive parity. The value found is consistent with that inferred by means of conventional methods from pion-nucleon scattering data. The study can also be considered as a phenomenological consistency check of the soliton picture of baryons. (orig.)
Measurement of Charged Current Coherent Pion Production by Neutrinos on Carbon at MINER$\
Energy Technology Data Exchange (ETDEWEB)
Mislivec, Aaron Robert [Univ. of Rochester, NY (United States)
2017-01-01
Neutrino-nucleus coherent pion production is a rare neutrino scattering process where the squared four-momentum transferred to the nucleus is small, a lepton and pion are produced in the forward direction, and the nucleus remains in its initial state. This process is an important background in neutrino oscillation experiments. Measurements of coherent pion production are needed to constrain models which are used to predict coherent pion production in oscillation experiments. This thesis reports measurements of νµ and νµ charged current coherent pion production on carbon for neutrino energies in the range 2 < Eν < 20 GeV. The measurements were made using data from MINERνA, which is a dedicated neutrino-nucleus scattering experiment that uses a fi scintillator tracking detector in the high-intensity NuMI neutrino beam at Fermilab. Coherent interactions were isolated from the data using only model-independent signatures of the reaction, which are a forward muon and pion, no evidence of nuclear breakup, and small four-momentum transfer to the nucleus. The measurements were compared to the coherent pion production model used by oscillation experiments. The data and model agree in the total interaction rate and are similar in the dependence of the interaction rate on the squared four- momentum transferred from the neutrino. The data and model disagree significantly in the pion kinematics. The measured νµ and νµ interaction rates are consistent, which supports model predictions that the neutrino and antineutrino interaction rates are equal.
1974-01-01
The survey of negative pion absorption reactions on light and medium nuclei was continued. Muon spin precession was studied using an iron target. An impulse approximation model of the pion absorption process implied that the ion will absorb almost exclusively on nucleon pairs, single nucleon absorption being suppressed by energy and momentum conservation requirements. For measurements on both paramagnetic and ferromagnetic iron, the external magnetic field was supplied by a large C-type electromagnet carrying a current of about 100 amperes.
Search for rare muon and pion decay modes with the Crystal Box detector
International Nuclear Information System (INIS)
Hoffman, C.M.; Bolton, R.D.; Bowman, J.D.
1986-01-01
New experimental upper limits for the branching ratios of the lepton-family-number nonconserving decays μ + → e + γ and μ + → e + γγ are presented. A new determination of γ, the ratio of pion axial-vector to vector form factors, from radiative pion decay is also reported. These results are from data taken with the Crystal Box detector at LAMPF
Search for rare muon and pion decay modes with the crystal box detector
International Nuclear Information System (INIS)
Piilonen, L.E.; Bolton, R.D.; Bowman, J.D.
1986-01-01
New experiental upper limits for the branching ratios of the lepton-family-number nonconserving decays μ + → e + γ and μ + → e + γγ are presented. A new determination of γ, the ratio of pion axial vector to vector form factors, from radiative pion decay is also reported. These results are from data taken with the Crystal Box detector at LAMPF. 11 refs., 7 figs
The pion structure function and scale breaking in Drell-Yan processes
International Nuclear Information System (INIS)
Moore, R.
1979-01-01
By use of the formalism of QCD, the structure functions of the nucleon and the pion obtained at Q 2 = m 2 sub(psi) is extended to higher values of Q 2 . These structure functions are then used to obtain predictions of scale-breaking effects in Drell-Yan lepton-pair production for both nucleon-nucleon and pion-nucleon cases. A comparison with recent experimental data is also presented. (author)
Energy cost of negative pion production on deuterium-tritium target
Energy Technology Data Exchange (ETDEWEB)
Kuzminov, V.V. (Petersburg Nuclear Physics Inst., Gatchina, St. Petersburg (Russian Federation)); Petrov, Yu.V. (Petersburg Nuclear Physics Inst., Gatchina, St. Petersburg (Russian Federation)); Shabelski, Yu.M. (Petersburg Nuclear Physics Inst., Gatchina, St. Petersburg (Russian Federation))
1993-12-01
The negative pion production by deuterons (T[sub 0] = 0.8 GeV/nucl.) was calculated for a cylindrical gaseous deuterium-tritium target (the density of DT-mixture is [phi] = 0.5). Revised cross sections of nucleon-nucleus interaction were used in a Monte Carlo simulation and multiple nucleon-nuclei collisions were taken into account. The energy cost of negative pion production is [epsilon][sub [pi][sup -
Rezhissura momenta / Dmitri Babitshenko
Babitshenko, Dmitri
2006-01-01
Šveitsi fotograafi Graham Mitchelli tööde näitusest "The Big Picture" Tallinna restoranis Pegasus. Autori kommentaarid. G. Mitchell on elanud pool aastat Tallinnas ning näitusefotod on tehtud Tallinnas ja selle ümbruses
Determination of the pion-nucleon coupling constant and scattering lengths
Ericson, Torleif Eric Oskar; Thomas, A W
2002-01-01
We critically evaluate the isovector GMO sum rule for forward pion-nucleon scattering using the recent precision measurements of negatively charged pion-proton and pion-deuteron scattering lengths from pionic atoms. We deduce the charged-pion-nucleon coupling constant, with careful attention to systematic and statistical uncertainties. This determination gives, directly from data a pseudoscalar coupling constant of 14.17+-0.05(statistical)+-0.19(systematic) or a pseudovector one of 0.0786(11). This value is intermediate between that of indirect methods and the direct determination from backward neutron-proton differential scattering cross sections. We also use the pionic atom data to deduce the coherent symmetric and antisymmetric sums of the negatively charged pion-proton and pion-neutron scattering lengths with high precision. The symmetric sum gives 0.0017+-0.0002(statistical)+-0.0008 (systematic) and the antisymmetric one 0.0900+-0.0003(statistical)+-0.0013(systematic), both in units of inverse charged pi...
Pion correlations in relativistic heavy ion collisions at Heavy Ion Spectrometer Systems (HISS)
International Nuclear Information System (INIS)
Christie, W.B. Jr.
1990-05-01
This thesis contains the setup, analysis and results of experiment E684H ''Multi-Pion Correlations in Relativistic Heavy Ion Collisions''. The goals of the original proposal were: (1) To initiate the use of the HISS facility in the study of central Relativistic Heavy Ion Collisions (RHIC). (2) To perform a second generation experiment for the detailed study of the pion source in RHIC. The first generation experiments, implied by the second goal above, refer to pion correlation studies which the Riverside group had performed at the LBL streamer chamber. The major advantage offered by moving the pion correlation studies to HISS is that, being an electronic detector system, as opposed to the Streamer Chamber which is a visual detector, one can greatly increase the statistics for a study of this sort. An additional advantage is that once one has written the necessary detector and physics analysis code to do a particular type of study, the study may be extended to investigate the systematics, with much less effort and in a relatively short time. This paper discusses the Physics motivation for this experiment, the experimental setup and detectors used, the pion correlation analysis, the results, and the conclusions possible future directions for pion studies at HISS. If one is not interested in all the details of the experiment, I believe that by reading the sections on intensity interferometry, the section the fitting of the correlation function and the systematic corrections applied, and the results section, one will get a fairly complete synopsis of the experiment
Liu, Shu-Guang; Fan, Hong-Yi
2010-03-01
We present a convenient approach to finding multi-partite entangled state with continuum variables, which is the common eigenvectors of center-of-mass coordinate and mass-weighted relative momenta, by decomposing the normally ordered Gaussian-form operator expressing the completeness relation which is constructed by analyzing the eigenvector equations. The whole derivation is based on the technique of integration within an ordered product of operators.
Guptaroy, P; De, B; Bhattacharya, D P
2001-01-01
The study aims at explaining the behaviour of some of the very important observables measured in the latest lead-lead collisions at CERN in the light of a variety of the sequential chain model. Calculated values, to our surprise, are in excellent agreement with the measurements, especially when the effect of cascading and rescattering is empirically introduced in the calculations of the average transverse momenta. Implications of the results are discussed. (17 refs).
Drongelen AW van; Roszek B; Hilbers-Modderman ESM; Kallewaard M; Wassenaar C; LGM
2002-01-01
This RIVM study was performed to gain insight into wheelchair-related incidents with powered and manual wheelchairs reported to the USA FDA, the British MDA and the Dutch Center for Quality and Usability Research of Technical Aids (KBOH). The data in the databases do not indicate that incidents with
Study of elastic pion scattering from 9Be, 28Si, 58Ni, and 208Pb at 162 MeV
International Nuclear Information System (INIS)
Devereux, M.J.
1979-05-01
Elastic pion scattering from 9 Be, 28 Si, 58 Ni, and 208 Pb at 162 MeV is analyzed and compared with an optical model theory which incorporates a pion--nucleon range. Excellent fits to the data are obtained in all but one case. The fitted values of the pion--nucleon range, as well as other fitted values are listed. 108 references
Directory of Open Access Journals (Sweden)
Surovtsev Yu.S.
2017-01-01
Full Text Available The basic shape of di-pion mass spectra in the two-pion transitions of both charmonia and bottomonia states is explained by a unified mechanism based on contributions of the ππ, KK̅, and ηη coupled channels including their interference. The role of the individual f0 resonances in shaping the di-pion mass distributions in the charmonia and bottomonia decays is considered.
Neutron skin of (208)pb from coherent pion photoproduction.
Tarbert, C M; Watts, D P; Glazier, D I; Aguar, P; Ahrens, J; Annand, J R M; Arends, H J; Beck, R; Bekrenev, V; Boillat, B; Braghieri, A; Branford, D; Briscoe, W J; Brudvik, J; Cherepnya, S; Codling, R; Downie, E J; Foehl, K; Grabmayr, P; Gregor, R; Heid, E; Hornidge, D; Jahn, O; Kashevarov, V L; Knezevic, A; Kondratiev, R; Korolija, M; Kotulla, M; Krambrich, D; Krusche, B; Lang, M; Lisin, V; Livingston, K; Lugert, S; MacGregor, I J D; Manley, D M; Martinez, M; McGeorge, J C; Mekterovic, D; Metag, V; Nefkens, B M K; Nikolaev, A; Novotny, R; Owens, R O; Pedroni, P; Polonski, A; Prakhov, S N; Price, J W; Rosner, G; Rost, M; Rostomyan, T; Schadmand, S; Schumann, S; Sober, D; Starostin, A; Supek, I; Thomas, A; Unverzagt, M; Walcher, Th; Zana, L; Zehr, F
2014-06-20
Information on the size and shape of the neutron skin on (208)Pb is extracted from coherent pion photoproduction cross sections measured using the Crystal Ball detector together with the Glasgow tagger at the MAMI electron beam facility. On exploitation of an interpolated fit of a theoretical model to the measured cross sections, the half-height radius and diffuseness of the neutron distribution are found to be c(n)=6.70±0.03(stat.) fm and a(n)=0.55±0.01(stat.)(-0.03)(+0.02)(sys.) fm, respectively, corresponding to a neutron skin thickness Δr(np)=0.15±0.03(stat.)(-0.03)(+0.01)(sys.) fm. The results give the first successful extraction of a neutron skin thickness with an electromagnetic probe and indicate that the skin of (208)Pb has a halo character. The measurement provides valuable new constraints on both the structure of nuclei and the equation of state for neutron-rich matter.
Study of isovector resonances with pion charge exchange
International Nuclear Information System (INIS)
Baer, H.W.; Bolton, R.; Bowman, J.D.
1982-01-01
Studies with the pion charge exchange reactions (π/sup +-/,π 0 ) at 164 MeV using the LAMPF π 0 spectrometer are yielding new results on the existence and systematic features of isovector resonances in nuclei. These experiments possess an unusually high signal/background ratio for isovector resonances of low-multipolarity. Results obtained to date are: (1) observation and angular disribution measurement of the giant dipole resonance in nuclei 12 C, 40 Ca, 90 Zr, and 120 Sn; and (2) observation and angular distribution measurements in the (π - ,π 0 ) reaction on 90 Zr and 120 Sn of large signals possessing the expected angular distribution shapes and magnitudes for the isovector monopole resonance. Excitation energies are near the hydrodynamical model values 170 A - /sup 1/3/ MeV. Differential cross sections are approximately 0.7 J 1 2 (qR) mb/sr. An overview of this experimental program, with emphasis on new results and how they correlate with existing knowledge on the isovector resonances, is presented
Pion production at 1800 in nucleus-nucleus collisions
International Nuclear Information System (INIS)
Chessin, S.A.
1983-05-01
A survey experiment of pion production at 180 0 in nucleus-nucleus collisions is presented. Beams of 1.05 GeV/A and 2.1 GeV/A protons, alphas, and carbon were used, as well as proton beams of 0.80 GeV, 3.5 GeV, and 4.89 GeV, and argon beams of 1.05 GeV/A and 1.83 GeV/A. This is the first such experiment to use the heavier beams. Targets used ranged from carbon to lead. An in-depth review of the literature, both experimental and theoretical, is also presented. The systematics of the data are discussed, and comparisons are made both with prior experiments and with the predictions of the models reviewed. The cross sections appear consistent with a simple single nucleon-nucleon collision picture, without the need for collective or other exotic effects. Suggestions for future work are made
Nuclear isovector giant resonances excited by pion single charge exchange
International Nuclear Information System (INIS)
King, B.H.
1993-07-01
This thesis is an experimental study of isovector giant resonances in light nuclei excited by pion single charge exchange reactions. Giant dipole resonances in light nuclei are known to be highly structured. For the mass 9 and 13 giant dipole resonances, isospin considerations were found to be very important to understanding this structure. by comparing the excitation functions from cross section measurements of the (π + , π 0 ) and (π, π 0 ) inclusive reactions, the authors determined the dominant isospin structure of the analog IVGR's. The comparison was made after decomposing the cross section into resonant and non-resonant components. This decomposition is made in the framework of strong absorption and quasi-free scattering. Measurements in the region of the isovector giant dipole resonances (IVGDR) were made to cover the inclusive angular distributions out to the second minimum. Study of the giant resonance decay process provides further understanding of the resonances. This study was carried out by observing the (π + , π 0 p) coincident reactions involving the resonances of 9 B and 13 N excited from 9 Be and 13 C nuclei. These measurements determined the spectra of the decay protons. This method also permitted a decomposition of the giant resonances into their isospin components. The multipolarities of the resonances were revealed by the decay proton angular correlations which, for dipoles, are of the form 1 + A 2 P 2 (cos θ)
Electroproduction of the neutral pion off 4He
Energy Technology Data Exchange (ETDEWEB)
Torayev, Bayram [Old Dominion Univ., Norfolk, VA (United States)
2016-12-01
Deeply virtual exclusive processes offer a unique opportunity to study the internal structure of the nucleon and nuclei. The goal of this work is to extract the beam-spin asymmetry in deeply virtual coherent neutral pion electroproduction, e^4He to e'^4He'pi^0, using the CLAS detector in the experimental Hall B at Thomas Jefferson National Accelerator Facility. The data were collected in 2009 with a 6 GeV longitudinally polarized electron beam impinging on a 30 cm long, 6 atm Helium-4 gaseous target. In order to ensure that the process is coherent, a new Radial Time Projection Chamber was used to detect and identify low energy recoil a-particles. The Beam Spin Asymmetry in the coherent deep exclusive regime was measured at Q^2 = 1.50 GeV^2, xB = 0.18 and -t = 0.14 GeV^2. The measured asymmetry has an amplitude of 10%+/-5% and has the opposite sign compared the asymmetry measured for pi^0 production on the proton.
Pion femtoscopy measurements in ALICE at the LHC
Graczykowski, Łukasz Kamil
2014-01-01
We present the results of two-pion Bose-Einstein correlations measured in Pb--Pb collisions at a center-of-mass energy sqrt(s_NN) = 2.76 TeV recorded by ALICE at the Large Hadron Collider. These types of correlations allow to extract, using the technique of femtoscopy (also known as Hanburry-Brown Twiss interferometry, or shortly HBT), the space-time characteristics of the source from the correlation calculated as a function of the pair momentum difference. The femtoscopic analysis was performed using both the Spherical Harmonics decomposition and the standard 3D Cartesian representation of the correlation function. The source sizes in three dimensions, the HBT radii, were extracted by fitting the experimental correlation functions. The resulting dependencies of the radii as a function of centrality and pair transverse momentum are shown. The results indicate the existence of a flowing medium and provide constraints on existing dynamical models. The ALICE Pb-Pb HBT radii are also compared to the pp analysis a...
Characterization of ParTI Phoswiches Using Charged Pion Beams
Churchman, Emily; Zarrella, Andrew; Youngs, Michael; Yennello, Sherry
2017-09-01
The Partial Truncated Icosahedron (ParTI) detector array consists of 15 phoswiches. Each phoswich is made of two scintillating components - a thallium-doped cesium iodide (CsI(Tl)) crystal and an EJ-212 scintillating plastic - coupled to a photomultiplier tube. Both materials have different scintillation times and are sensitive to both charged and neutral particles. The type of particle and amount of energy deposited determine the shape of the scintillation pulse as a function of time. By integrating the fast and slow signals of the scintillation pulses, a ``Fast vs. Slow Integration'' plot can be created that produces particle identification lines based on the energy deposited in the scintillating materials. Four of these phoswiches were taken to the Paul Scherrer Institute (PSI) in Switzerland where π + , π-, and proton beams were scattered onto the phoswiches to demonstrate their particle identification (PID) capabilities. Using digitizers to record the detector response waveforms, pions can also be identified by the characteristic decay pulse of the muon daughters.
Neutron Skin of Pb208 from Coherent Pion Photoproduction
Tarbert, C. M.; Watts, D. P.; Glazier, D. I.; Aguar, P.; Ahrens, J.; Annand, J. R. M.; Arends, H. J.; Beck, R.; Bekrenev, V.; Boillat, B.; Braghieri, A.; Branford, D.; Briscoe, W. J.; Brudvik, J.; Cherepnya, S.; Codling, R.; Downie, E. J.; Foehl, K.; Grabmayr, P.; Gregor, R.; Heid, E.; Hornidge, D.; Jahn, O.; Kashevarov, V. L.; Knezevic, A.; Kondratiev, R.; Korolija, M.; Kotulla, M.; Krambrich, D.; Krusche, B.; Lang, M.; Lisin, V.; Livingston, K.; Lugert, S.; MacGregor, I. J. D.; Manley, D. M.; Martinez, M.; McGeorge, J. C.; Mekterovic, D.; Metag, V.; Nefkens, B. M. K.; Nikolaev, A.; Novotny, R.; Owens, R. O.; Pedroni, P.; Polonski, A.; Prakhov, S. N.; Price, J. W.; Rosner, G.; Rost, M.; Rostomyan, T.; Schadmand, S.; Schumann, S.; Sober, D.; Starostin, A.; Supek, I.; Thomas, A.; Unverzagt, M.; Walcher, Th.; Zana, L.; Zehr, F.; Crystal Ball at MAMI; A2 Collaboration
2014-06-01
Information on the size and shape of the neutron skin on Pb208 is extracted from coherent pion photoproduction cross sections measured using the Crystal Ball detector together with the Glasgow tagger at the MAMI electron beam facility. On exploitation of an interpolated fit of a theoretical model to the measured cross sections, the half-height radius and diffuseness of the neutron distribution are found to be cn=6.70±0.03(stat.) fm and an=0.55±0.01(stat.)-0.03+0.02(sys.) fm, respectively, corresponding to a neutron skin thickness Δrnp=0.15±0.03(stat.)-0.03+0.01(sys.) fm. The results give the first successful extraction of a neutron skin thickness with an electromagnetic probe and indicate that the skin of Pb208 has a halo character. The measurement provides valuable new constraints on both the structure of nuclei and the equation of state for neutron-rich matter.
Beam-spin Asymmetries from Semi-inclusive Pion Electroproduction
Energy Technology Data Exchange (ETDEWEB)
Gohn, Wesley P. [University of Connecticut, Storrs, CT (United States); Avakian, Harut A. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Joo, Kyungseon [University of Connecticut, Storrs, CT (United States); Ungaro, Maurizio [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
2014-04-01
We have measured the moment A{sup sin{phi}}{sub LU} corresponding to the polarized electron beam-spin asymmetry in SIDIS. A{sup sin{phi}}{sub LU} is a twist-3 quantity providing information about quark-gluon correlations. Data were taken with the CLAS Spectrometer at Jefferson Lab using a 5.498 GeV longitudinally polarized electron beam and an unpolarized liquid hydrogen target. All three pion channels (pi{sup +}, pi{sup 0} and pi{sup -}) were measured simultaneously over a large range of kinematics within the virtuality range Q{sup 2} ~ 1.0-4.5 GeV{sup 2}. The observable was measured with good statistical precision over a large range of z, P{sub T}, x{sub B}, and Q{sup 2}, which permits comparison with several reaction models. The discussed measurements provide an upgrade in statistics over previous measurements, and serve as the first evidence for the negative sign of the {pi}{sup -} sin{phi} Moment.
Roy-Steiner equations for pion-nucleon scattering
Ditsche, C.; Hoferichter, M.; Kubis, B.; Meißner, U.-G.
2012-06-01
Starting from hyperbolic dispersion relations, we derive a closed system of Roy-Steiner equations for pion-nucleon scattering that respects analyticity, unitarity, and crossing symmetry. We work out analytically all kernel functions and unitarity relations required for the lowest partial waves. In order to suppress the dependence on the high energy regime we also consider once- and twice-subtracted versions of the equations, where we identify the subtraction constants with subthreshold parameters. Assuming Mandelstam analyticity we determine the maximal range of validity of these equations. As a first step towards the solution of the full system we cast the equations for the π π to overline N N partial waves into the form of a Muskhelishvili-Omnès problem with finite matching point, which we solve numerically in the single-channel approximation. We investigate in detail the role of individual contributions to our solutions and discuss some consequences for the spectral functions of the nucleon electromagnetic form factors.
Pion production and the nuclear equation of state
International Nuclear Information System (INIS)
Harris, J.W.; Odyniec, G.; Pugh, H.G.
1984-10-01
There has been considerable recent interest in the nuclear equation of state and how it may be determined in relativistic nucleus-nucleus collisions. In these collisions extremely high temperatures are reached and compression to densities several times that of normal nuclear matter are predicted. This affords us the unique opportunity to study, in a somewhat controlled manner, the behavior of nuclear matter under these extreme conditions. If the observables that are measured in experiments can be related in a quantitative way to state variables of the system then the equation of state can be extracted. This relation plays a very important role in understanding the formation and collapse of supernovae and the stability and structure of neutron stars. Furthermore, it can be used to test and constrain field theoretical approaches to nuclear matter and to help to better understand the dynamics of high energy nucleus-nucleus collisions. In this presentation the relationship between the nuclear equation of state and relativistic nucleus-nucleus collisions will be discussed with an emphasis on how to extract the former. That a high density state of the collision should exist will be shown. One observable, namely the pion multiplicity, will be shown to survive the succeeding stages of the collision process to provide information on the equation of state at high densities. The resulting equation of state will be presented and discussed in the light of recent theoretical development. 34 refs., 12 figs
International Nuclear Information System (INIS)
Sadler, M.E.; Isenhower, L.D.
1990-01-01
This report discusses the following: pion-nucleon program; a search for neutral pions from the spontaneous fission of 252 Cf; elastic and inelastic pion scattering on 3 H and 3 He; nuclear dependence of charm and beauty quark production and a study of two-prong decays of neutral B mesons; measurement of π - p → π 0 n in the cusp region at the Leningrad Nuclear Physics Institute (LNPI); a test of consistency of low-energy pion-nucleon differential cross sections with total cross sections; and design of a high energy photon calorimeter for the neutral meson spectrometer
Producció de partícules a la factoria de Pions del GSI de Darmstadt
Ardid Ramírez, Miguel
2002-01-01
RESUM Recentment s'ha installat un feix secundari de pions al laboratori d'ions pesants GSI de Darmstadt (Alemanya) per a produir feixos de pions amb moment fins a 3 GeV/c. Aquesta és la primera vegada que feixos d'ions pesants són utilitzats per a aquesta finalitat. La tesi investiga la validesa d'aquest aspecte i estudia exhaustívament el feix de pions abans mencionat. Primer, es fa una revisió de les dades experimentals de la producció de pions en reaccions nuclears i es presenten algun...
International Nuclear Information System (INIS)
Dorokhov, A.E.; Kanokov, Z.; Musakhanov, M.M.; Rakhimov, A.M.
1989-01-01
Pion production on a nucleon is studied in the chiral bag model (CBM). A CBM version is investigated in which the pions get into the bag and interact with quarks in a pseudovector way in the entire volume. Charged pion photoproduction amplitudes are found taking into account the recoil nucleon motion effects. Angular and energy distributions of charged pions, polarization of the recoil nucleon, multipoles are calculated. The recoil effects are shon to give an additional contribution to the static approximation of order of 10-20%. At bag radius value R=1 in the calculations are consistent with the experimental data
Pion double charge exchange above the Δ3/2,3/2 resonance
International Nuclear Information System (INIS)
Williams, A.L.
1991-11-01
The first exclusive measurements of (π + π - ) reactions on several nuclei for incident pion energies from 300 to 550 MeV are reported. The measurements were made with the Large Acceptance Spectrometer at the P 3 channel of the Clinton P. Anderson Meson Physics Facility. A description of the experimental setup is given which includes a discussion of modifications to the spectrometer and channel implemented specifically for these measurements. Forward angle excitation functions for transitions to the double isobaric analog state (DIAS) are found to be relatively flat for these energies. This energy dependence is reproduced by optical and Glauber calculations, but not by a six-quark bag prediction. The mass dependence of the DIAS was found to qualitatively agree with the predicted mass dependence from optical calculations. One angular distribution was measured for 5 degrees ≤ Θ lab ≤ 35 degrees for 18 O(π + π - ) 18 Ne. The DIAS cross section falls by more than one order of magnitude over this range, as predicted by both Glauber and optical model calculations. Data for f 7/2 -shell nuclei were examined with a two-amplitude model based on seniority-zero shell model wavefunctions which features expressions for cross sections for DIAS transitions and transitions to nonanalog ground-states. The cross sections for T = 1 nuclei are found to be inconsistent with the predictions of the model. One excitation function for nonanalog transitions was measured and is relatively flat with energy. The continuum of nonanalog states near threshold was found to decrease with energy
Pion propagator in relativistic quantum field theories of the nuclear many-body problem
International Nuclear Information System (INIS)
Matsui, T.; Serot, B.D.
1982-01-01
Pion interactions in the nuclear medium are studied using renormalizable relativistic quantum field theories. Previous studies using pseudoscalar πN coupling encountered difficulties due to the large strength of the πNN vertex. We therefore formulate renormalizable field theories with pseudovector πN coupling using techniques introduced by Weinberg and Schwinger. Calculations are performed for two specific models; the scalar-vector theory of Walecka, extended to include π and rho mesons in a non-chiral fashion, and the linear sigma-model with an additional neutral vector meson. Both models qualitatively reproduce low-energy πN phenomenology and lead to nuclear matter saturation in the relativistic Hartree formalism, which includes baryon vacuum fluctuations. The pions propagator is evaluated in the one-nucleon-loop approximation, which corresponds to a relativistic random-phase approximation built on the Hartree ground state. Virtual NN-bar loops are included, and suitable renormalization techniques are illustrated. The local-density approximation is used to compare the threshold pion self-energy to the s-wave pion-nucleus optical potential. In the non-chiral model, s-wave pion-nucleus scattering is too large in both pseudoscalar and pseudovector calculations, indicating that additional constraints must be imposed on the Lagrangian. In the chiral model, the threshold self-energy vanishes automatically in the pseudovector case, but does so for pseudoscalar coupling only if the baryon effective mass is chosen self-consistently Since extrapolation from free space to nuclear density can lead to large effects, pion propagation in the medium can determine which πN coupling is more suitable for the relativistic nuclear many-body problem. Conversely, pion interactions constrain the model Lagrangian and the nuclear matter equation of state. An approximately chiral model with pseudovector coupling is favored
Measurements on GaAs strip and pixel detectors in a 50 GeV pion beam
Energy Technology Data Exchange (ETDEWEB)
Syben, O. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Arbabi, S. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Braunschweig, W. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Breibach, J. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Chu, Z. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Karpinski, W. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Krais, R. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Kubicki, Th. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Luebelsmeyer, K. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Rente, C. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Siedling, R. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Tenbusch, F. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Toporowski, M. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Wittmer, B. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.; Xiao, W.J. [Technische Hochschule Aachen (Germany). 1. Physikalisches Inst.
1997-04-01
GaAs strip and pixel detectors constructed in Aachen have been tested at CERN in a 50 GeV pion beam in September 1995 in collaboration with the CMS Tracker group. The strip detectors had a pitch of 100 {mu}m and were made of a 250 {mu}m thick Freiberger SI-GaAs wafer. The three strip detectors had a strip width of 25, 50 and 75 {mu}m, respectively. Using the fast PreMux128 preamplifier multiplexer chip ({tau}{sub p}=50 ns) a signal to noise ratio of 15 was obtained for the widest strips at normal beam incidence for a bias voltage of 170 V. The 8 x 8 pixel arrays with a pixel size of 1 x 1 mm{sup 2} and 0.5 x 0.5 mm{sup 2}, respectively, were read out with the PreMux128 as well. Here a signal of 12500e{sup -} was obtained for both detectors, leading to a maximum signal to noise ratio of 20 at perpendicular beam incidence and 170 V bias voltage. (orig.).
Kochemasov, G. G.
2009-04-01
Mars: destructive and constructive processes in its crust reflecting tendencies of leveling angular momenta of tropics and extra-tropics. G. Kochemasov IGEM of the Russian Academy of Sciences A globular shape of rotating celestial bodies means that their tropical and extra-tropical belts have significantly different angular momenta. But such unevenness in a single body is disturbing because it increases level of tectonic stresses and energetic state what is against natural trends for minimizing these characteristics. To level partly this inequality bodies tend to diminish radius and mass in tropics and increase them in extra-tropics. Traces of these destructive and constructive actions are fixed in planetary geospheres of different classes of celestial bodies: Sun, planets, satellites, and asteroids. The remote geologic mapping of Mars reveals these traces rather obviously. "Mysterious" contact zone of the martian lowlands and highlands with obvious traces of destruction expressed in widespread development of chaotic and fretted terrains is a good evidence that could be considered in comparison with the equatorial and tropical belts of some other planetary bodies [1]. At Earth the wide planetary long tropical zone is marked by its destruction. It is demonstrated by development of numerous islands of the Archipelago between the South-East Asia and Australia. In Africa and South America huge depressions of the Congo and Amazon Rivers develops where the Archean crust is subsided to depths of more than 2 km. In the Pacific along the equator numerous islands of Micronesia occur. Subsidence of the basaltic oceanic crust is followed by an intensive folding and faulting of basalt and sedimentary layers as a larger mass must be held by a smaller space (a planetary radius is diminished). Seismicity of the tropical zone is significantly higher than outside of it that means more intensive destruction in the crust and the upper mantle of tropics. Mantle derived diamonds are
Low energy constituent quark and pion effective couplings in a weak external magnetic field
Braghin, Fábio L.
2018-03-01
An effective model with pions and constituent quarks in the presence of a weak external background electromagnetic field is derived by starting from a dressed one gluon exchange quark-quark interaction. By applying the auxiliary field and background field methods, the structureless pion limit is considered to extract effective pion and constituent quark couplings in the presence of a weak magnetic field. The leading terms of a large quark and gluon masses expansion are obtained by resolving effective coupling constants which turn out to depend on a weak magnetic field. Two pion field definitions are considered for that. Several relations between the effective coupling constants and parameters can be derived exactly or in the limit of very large quark mass at zero and weak constant magnetic field. Among these ratios, the Gell-Mann-Oakes-Renner and the quark level Goldberger-Treiman relations are obtained. In addition to that, in the pion sector, the leading terms of Chiral Perturbation Theory coupled to the electromagnetic field are recovered. Some numerical estimates are provided for the effective coupling constants and parameters.
International Nuclear Information System (INIS)
Francois, P.
1996-01-01
We undertook a study programme at the end of 1991. To start with, we performed some exploratory studies aimed at learning some preliminary lessons on this type of analysis: Assessment of the interest of probabilistic incident analysis; possibility of using PSA scenarios; skills and resources required. At the same time, EPN created a working group whose assignment was to define a new approach for analysis of incidents on NPPs. This working group gave thought to both aspects of Operating Feedback that EPN wished to improve: Analysis of significant incidents; analysis of potential consequences. We took part in the work of this group, and for the second aspects, we proposed a method based on an adaptation of the event-tree method in order to establish a link between existing PSA models and actual incidents. Since PSA provides an exhaustive database of accident scenarios applicable to the two most common types of units in France, they are obviously of interest for this sort of analysis. With this method we performed some incident analyses, and at the same time explores some methods employed abroad, particularly ASP (Accident Sequence Precursor, a method used by the NRC). Early in 1994 EDF began a systematic analysis programme. The first, transient phase will set up methods and an organizational structure. 7 figs
Fireball model analyses of small and large transverse momentum pion distributions at ISR energies
International Nuclear Information System (INIS)
Hama, Mitsuru; Nagasaki, Masayuki; Suzuki, Haruo
1977-01-01
By taking account of the production and subsequent two-step decay of the large fireball called SH-quantum observed since 1967 in cosmic ray experiments in addition to the production of the usual small fireball called H-quantum, we obtain a good fit for the inclusive one-pion distributions at large angle in ISR energy region. The inclusive distributions for large transverse momentum pions can be fitted with the production cross section of SH-quantum sigma sub(SH) asymptotically equals 0.4 and 2 mb at √s = 23 and 63 GeV, respectively. Due to the large decay multiplicity of SH-quantum, these small production cross sections of SH-quantum account also for the increase around 40% of the inclusive distributions for small transverse momentum pions in the ISR energy region √s = 23 -- 63 GeV. (auth.)
Pion generalized parton distributions within a fully covariant constituent quark model
Energy Technology Data Exchange (ETDEWEB)
Fanelli, Cristiano [Massachusetts Institute of Technology, Cambridge, MA (United States). Lab. for Nuclear Science; Pace, Emanuele [' ' Tor Vergata' ' Univ., Rome (Italy). Physics Dept.; INFN Sezione di TorVergata, Rome (Italy); Romanelli, Giovanni [Rutherford-Appleton Laboratory, Didcot (United Kingdom). STFC; Salme, Giovanni [Istituto Nazionale di Fisica Nucleare, Rome (Italy); Salmistraro, Marco [Rome La Sapienza Univ. (Italy). Physics Dept.; I.I.S. G. De Sanctis, Rome (Italy)
2016-05-15
We extend the investigation of the generalized parton distribution for a charged pion within a fully covariant constituent quark model, in two respects: (1) calculating the tensor distribution and (2) adding the treatment of the evolution, needed for achieving a meaningful comparison with both the experimental parton distribution and the lattice evaluation of the so-called generalized form factors. Distinct features of our phenomenological covariant quark model are: (1) a 4D Ansatz for the pion Bethe-Salpeter amplitude, to be used in the Mandelstam formula for matrix elements of the relevant current operators, and (2) only two parameters, namely a quark mass assumed to be m{sub q} = 220 MeV and a free parameter fixed through the value of the pion decay constant. The possibility of increasing the dynamical content of our covariant constituent quark model is briefly discussed in the context of the Nakanishi integral representation of the Bethe-Salpeter amplitude. (orig.)
Electron/pion identification in the CBM TRD using a multilayer perceptron
International Nuclear Information System (INIS)
Akishina, E.P.; Akishina, T.P.; Ivanov, V.V.; Maevskaya, A.I.; Afanas'ev, O.A.
2008-01-01
The problem of electron/pion identification in the CBM experiment based on the measurements of energy losses and transition radiation in the TRD detector is discussed. A possibility to solve such a problem by applying an artificial neural network (ANN) is considered. As input information for the network we used both the samples of energy losses of pions or electrons in the TRD absorbers and the 'clever' variable obtained on the basis of the original data. We show that usage of this new variable permits one to reach a reliable level of particle recognition no longer than after 10-20 training epochs; there are practically no fluctuations against the trend, and the needed level of pions suppression is obtained under the condition of a minimal loss of electrons
Backward asymmetry measurements in the elastic pion-proton scattering at resonance energies
Energy Technology Data Exchange (ETDEWEB)
Alekseev, I.G.; Budkovsky, P.E.; Kanavets, V.P.; Koroleva, L.I.; Morozov, B.V.; Nesterov, V.M.; Ryltsov, V.V.; Sulimov, A.D.; Svirida, D.N. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Bazhanov, N.A.; Bunyatova, E.I.; Zolin, L.S. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Beloglazov, Yu.A.; Filimonov, E.A.; Kovalev, A.I.; Novinsky, D.V.; Shchedrov, V.A.; Sumachev, V.V.; Trautman, V.Yu. [Petersburg Nuclear Physics Institute, Gatchina (Russian Federation)
2009-02-15
The asymmetry parameter P was measured for the elastic pion-proton scattering in the very backward angular region of {theta}{sub CM}{approx}150-170 at several pion beam energies in the invariant-mass range containing most of the pion-proton resonances. The general goal of the experimental program was to provide new data for partial wave analyses in order to resolve their uncertainties in the baryon resonance region to allow the unambiguous baryon spectrum reconstructions. Until recently the parameter P was not measured in the examined domain that might be explained by the extremely low cross-section. At the same time the predictions of various partial wave analyses are far from agreement in some kinematic areas and specifically those areas were chosen for the measurements where the disagreement is most pronouncing. The experiment was performed at the ITEP U-10 proton synchrotron, Moscow, by the ITEP-PNPI Collaboration in the latest 5 years. (orig.)
Backward asymmetry measurements in the elastic pion-proton scattering at resonance energies
Alekseev, I. G.; Bazhanov, N. A.; Beloglazov, Yu. A.; Budkovsky, P. E.; Bunyatova, E. I.; Filimonov, E. A.; Kanavets, V. P.; Kovalev, A. I.; Koroleva, L. I.; Morozov, B. V.; Nesterov, V. M.; Novinsky, D. V.; Ryltsov, V. V.; Shchedrov, V. A.; Sulimov, A. D.; Sumachev, V. V.; Svirida, D. N.; Trautman, V. Yu.; Zolin, L. S.
2009-02-01
The asymmetry parameter P was measured for the elastic pion-proton scattering in the very backward angular region of θ_{CM}^{} ≈ 150 - 170° at several pion beam energies in the invariant-mass range containing most of the pion-proton resonances. The general goal of the experimental program was to provide new data for partial wave analyses in order to resolve their uncertainties in the baryon resonance region to allow the unambiguous baryon spectrum reconstructions. Until recently the parameter P was not measured in the examined domain that might be explained by the extremely low cross-section. At the same time the predictions of various partial wave analyses are far from agreement in some kinematic areas and specifically those areas were chosen for the measurements where the disagreement is most pronouncing. The experiment was performed at the ITEP U-10 proton synchrotron, Moscow, by the ITEP-PNPI Collaboration in the latest 5 years.
Gluon distributions in nucleons and pions at a low resolution scale
International Nuclear Information System (INIS)
Christiansen, H.R.
2000-10-01
In this paper we study the gluon distribution functions in nucleons and pions at a low resolution Q 2 scale. This is an important issue since parton densities at low Q 2 have always been taken as an external input which is adjusted through DGLAP evolution to fit the experimental data at higher scales. Here, in the framework of a model recently developed, it is shown that the hypothetical cloud of neutral pions surrounding nucleons and pions appears to be responsible for the characteristic valence-like gluon distributions needed at the initial low scale. As an additional result, we get the remarkable prediction that neutral and charged ions have different intrinsic sea flavor contents. (author)
Effects of ρ-meson width on pion distributions in heavy-ion collisions
Directory of Open Access Journals (Sweden)
Pasi Huovinen
2017-06-01
Full Text Available The influence of the finite width of ρ meson on the pion momentum distribution is studied quantitatively in the framework of the S-matrix approach combined with a blast-wave model to describe particle emissions from an expanding fireball. We find that the proper treatment of resonances which accounts for their production dynamics encoded in data for partial wave scattering amplitudes can substantially modify spectra of daughter particles originating in their two body decays. In particular, it results in an enhancement of the low-pT pions from the decays of ρ mesons which improves the quantitative description of the pion spectra in heavy ion collisions obtained by the ALICE collaboration at the LHC energy.
Detection of the characteristic pion-decay signature in supernova remnants.
Ackermann, M; Ajello, M; Allafort, A; Baldini, L; Ballet, J; Barbiellini, G; Baring, M G; Bastieri, D; Bechtol, K; Bellazzini, R; Blandford, R D; Bloom, E D; Bonamente, E; Borgland, A W; Bottacini, E; Brandt, T J; Bregeon, J; Brigida, M; Bruel, P; Buehler, R; Busetto, G; Buson, S; Caliandro, G A; Cameron, R A; Caraveo, P A; Casandjian, J M; Cecchi, C; Celik, O; Charles, E; Chaty, S; Chaves, R C G; Chekhtman, A; Cheung, C C; Chiang, J; Chiaro, G; Cillis, A N; Ciprini, S; Claus, R; Cohen-Tanugi, J; Cominsky, L R; Conrad, J; Corbel, S; Cutini, S; D'Ammando, F; de Angelis, A; de Palma, F; Dermer, C D; do Couto e Silva, E; Drell, P S; Drlica-Wagner, A; Falletti, L; Favuzzi, C; Ferrara, E C; Franckowiak, A; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Germani, S; Giglietto, N; Giommi, P; Giordano, F; Giroletti, M; Glanzman, T; Godfrey, G; Grenier, I A; Grondin, M-H; Grove, J E; Guiriec, S; Hadasch, D; Hanabata, Y; Harding, A K; Hayashida, M; Hayashi, K; Hays, E; Hewitt, J W; Hill, A B; Hughes, R E; Jackson, M S; Jogler, T; Jóhannesson, G; Johnson, A S; Kamae, T; Kataoka, J; Katsuta, J; Knödlseder, J; Kuss, M; Lande, J; Larsson, S; Latronico, L; Lemoine-Goumard, M; Longo, F; Loparco, F; Lovellette, M N; Lubrano, P; Madejski, G M; Massaro, F; Mayer, M; Mazziotta, M N; McEnery, J E; Mehault, J; Michelson, P F; Mignani, R P; Mitthumsiri, W; Mizuno, T; Moiseev, A A; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Nakamori, T; Nemmen, R; Nuss, E; Ohno, M; Ohsugi, T; Omodei, N; Orienti, M; Orlando, E; Ormes, J F; Paneque, D; Perkins, J S; Pesce-Rollins, M; Piron, F; Pivato, G; Rainò, S; Rando, R; Razzano, M; Razzaque, S; Reimer, A; Reimer, O; Ritz, S; Romoli, C; Sánchez-Conde, M; Schulz, A; Sgrò, C; Simeon, P E; Siskind, E J; Smith, D A; Spandre, G; Spinelli, P; Stecker, F W; Strong, A W; Suson, D J; Tajima, H; Takahashi, H; Takahashi, T; Tanaka, T; Thayer, J G; Thayer, J B; Thompson, D J; Thorsett, S E; Tibaldo, L; Tibolla, O; Tinivella, M; Troja, E; Uchiyama, Y; Usher, T L; Vandenbroucke, J; Vasileiou, V; Vianello, G; Vitale, V; Waite, A P; Werner, M; Winer, B L; Wood, K S; Wood, M; Yamazaki, R; Yang, Z; Zimmer, S
2013-02-15
Cosmic rays are particles (mostly protons) accelerated to relativistic speeds. Despite wide agreement that supernova remnants (SNRs) are the sources of galactic cosmic rays, unequivocal evidence for the acceleration of protons in these objects is still lacking. When accelerated protons encounter interstellar material, they produce neutral pions, which in turn decay into gamma rays. This offers a compelling way to detect the acceleration sites of protons. The identification of pion-decay gamma rays has been difficult because high-energy electrons also produce gamma rays via bremsstrahlung and inverse Compton scattering. We detected the characteristic pion-decay feature in the gamma-ray spectra of two SNRs, IC 443 and W44, with the Fermi Large Area Telescope. This detection provides direct evidence that cosmic-ray protons are accelerated in SNRs.
Effects of ρ-meson width on pion distributions in heavy-ion collisions
Huovinen, Pasi; Lo, Pok Man; Marczenko, Michał; Morita, Kenji; Redlich, Krzysztof; Sasaki, Chihiro
2017-06-01
The influence of the finite width of ρ meson on the pion momentum distribution is studied quantitatively in the framework of the S-matrix approach combined with a blast-wave model to describe particle emissions from an expanding fireball. We find that the proper treatment of resonances which accounts for their production dynamics encoded in data for partial wave scattering amplitudes can substantially modify spectra of daughter particles originating in their two body decays. In particular, it results in an enhancement of the low-pT pions from the decays of ρ mesons which improves the quantitative description of the pion spectra in heavy ion collisions obtained by the ALICE collaboration at the LHC energy.
Photon- and pion-induced reactions in the few body systems
International Nuclear Information System (INIS)
Laget, J.M.
1985-05-01
The study of the interplay of the degrees of freedom of the many nuclear system and the internal degrees of freedom of its constituents is reviewed. First nucleon-nucleon interaction mechanisms are recalled in relation to the interaction range. It appears that pion and photon induced reactions should provide two complementary ways to disentangle these various mechanisms. Most of pion and photon induced reactions, performed until now, can be understood in terms of nucleons, pions and deltas. But after a short description of the method of analysis of the reactions it is shown that this agreement is achieved at the price of the adjustment of two parameters (the πNN form factor and the rho-nucleon coupling contant) which may simulate more subtle short range effects. Then the relevance of the analysis of the same reactions in terms of quark degrees of freedom is discussed briefly
Risks for cancer induction by pion radiation in the peak- and plateau region
International Nuclear Information System (INIS)
Cottier, H.; Fritz-Niggli, H.; Froehlich, E.; Heinzell, F.; Nichel, C.; Rao, K.
In the foreground of an evaluation of the suitability of negative protons for cancer therapy there is, beside the analysis of pion effect on malignant cells, also the reaction of healthy tissue. The observation that neutrons at the lowest dose-rate can induce breast cancer and our own results after pion radiation in the peak-region necessitate a broadly planned, urgent investigation of these delayed damages. We will consider radiations at the plateau- and peak-region, the results of which should be of utmost interest for the comparison of neutron- and pion therapy. There are indications that the RBE of a high LET radiation is extremely large for the tumor induction. We will investigate especially the development of mammary cancers in variously aged mice with a low spontaneous tumor rate and C 3 H mice with a high cancer expectancy
International Nuclear Information System (INIS)
Hayami, Masao; Seino, Junji; Nakai, Hiromi
2015-01-01
An efficient algorithm for the rapid evaluation of electron repulsion integrals is proposed. The present method, denoted by accompanying coordinate expansion and transferred recurrence relation (ACE-TRR), is constructed using a transfer relation scheme based on the accompanying coordinate expansion and recurrence relation method. Furthermore, the ACE-TRR algorithm is extended for the general-contraction basis sets. Numerical assessments clarify the efficiency of the ACE-TRR method for the systems including heavy elements, whose orbitals have long contractions and high angular momenta, such as f- and g-orbitals
Reaction π-p→X deg n, X deg → 2γ at momenta 15 and 40 GeV/c
International Nuclear Information System (INIS)
Apel, W.D.; Bertolucci, E; Donskov, S.V.
1974-01-01
The cross sections for reaction π - p→X deg n with X deg → 2γ decay have been measured at momenta 15 and 40 GeV/c. About 500 events have been detected. A hodoscope spectrometer with the computer on-line was used to detect photon pairs. t-dependence of differential cross section has been obtained similar to that of reaction π - p→eta deg n. From the ratio of differential cross section for X deg and eta deg production at t=0 an angle of the singlet-octet mixing of pseudoscalar mesons has been found to be equal to β=-19 deg
Hayami, Masao; Seino, Junji; Nakai, Hiromi
2015-05-01
An efficient algorithm for the rapid evaluation of electron repulsion integrals is proposed. The present method, denoted by accompanying coordinate expansion and transferred recurrence relation (ACE-TRR), is constructed using a transfer relation scheme based on the accompanying coordinate expansion and recurrence relation method. Furthermore, the ACE-TRR algorithm is extended for the general-contraction basis sets. Numerical assessments clarify the efficiency of the ACE-TRR method for the systems including heavy elements, whose orbitals have long contractions and high angular momenta, such as f- and g-orbitals.
Azimuthally Differential Pion Femtoscopy in Pb-Pb Collisions at √sNN = 2.76 TeV
Adamová, D.; Aggarwal, M. M.; Aglieri Rinella, G.; Agnello, M.; Agrawal, N.; Ahammed, Z.; Ahmad, S.; Ahn, S. U.; Aiola, S.; Akindinov, A.; Alam, S. N.; Albuquerque, D. S. D.; Aleksandrov, D.; Alessandro, B.; Alexandre, D.; Alfaro Molina, R.; Alici, A.; Alkin, A.; Alme, J.; Alt, T.; Altinpinar, S.; Altsybeev, I.; Alves Garcia Prado, C.; Janssen, M M; Andrei, C.; Andrews, H. A.; Andronic, A.; Anguelov, V.; Anson, C. D.; Antičić, T.; Antinori, F.; Antonioli, P.; Anwar, R.; Aphecetche, L.; Appelshäuser, H.; Arcelli, S.; Arnaldi, R.; Arnold, O. W.; Arsene, I. C.; Arslandok, M.; Audurier, B.; Augustinus, A.; Averbeck, R.; Azmi, M. D.; Badalà, A.; Baek, Y. W.; Bagnasco, S.; Bailhache, R.; Bala, R.; Baldisseri, A.; Ball, M.C.; Baral, R. C.; Barbano, A. M.; Barbera, R.; Barile, F.; Barioglio, L.; Barnaföldi, G. G.; Barnby, L. S.; Barret, V.; Bartalini, P.; Barth, K.; Bartke, J.; Bartsch, E.; Basile, M.; Bastid, N.; Basu, S.; Bathen, B.; Batigne, G.; Batista Camejo, A.; Batyunya, B.; Batzing, P. C.; Bearden, I. G.; Beck, H.; Bedda, C.|info:eu-repo/dai/nl/411263188; Behera, N. K.; Belikov, I.; Bellini, F.; Bello Martinez, H.; Bellwied, R.; Beltran, L. G. E.; Belyaev, V.; Bencedi, G.; Beole, S.; Bercuci, A.; Berdnikov, Y.; Berenyi, D.; Bertens, R. A.|info:eu-repo/dai/nl/371577810; Berzano, D.; Betev, L.; Bhasin, A.; Bhat, I. R.; Bhati, A. K.; Bhattacharjee, B.; Bhom, J.; Bianchi, L.; Bianchi, N.; Bianchin, C.|info:eu-repo/dai/nl/371578248; Bielčík, J.; Bielčíková, J.; Bilandzic, A.; Biro, G.; Biswas, R.; Biswas, S.; Blair, J. T.; Blau, D.; Blume, C.; Boca, G.; Bock, F.; Bogdanov, A.; Boldizsár, L.; Bombara, M.; Bonomi, G.; Bonora, M.; Book, J.; Borel, H.; Borissov, A.; Borri, M.; Botta, E.; Bourjau, C.; Braun-Munzinger, P.; Bregant, M.; Broker, T. A.; Browning, T. A.; Broz, M.; Brucken, E. J.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Bufalino, S.; Buhler, P.; Iga Buitron, S. A.; Buncic, P.; Busch, O.; Buthelezi, Z.; Butt, J. B.; Buxton, J. T.; Cabala, J.; Caffarri, D.; Caines, H.; Caliva, A.|info:eu-repo/dai/nl/411885812; Calvo Villar, E.; Camerini, P.; Capon, A. A.; Carena, F.; Carena, W.; Carnesecchi, F.; Castillo Castellanos, J.; Castro, A. J.; Casula, E. A R; Ceballos Sanchez, C.; Cerello, P.; Chang, B.; Chapeland, S.; Chartier, M.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Chauvin, A.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chibante Barroso, V.; Chinellato, D. D.; Cho, Sukhee; Chochula, P.; Choi, K.; Chojnacki, M.|info:eu-repo/dai/nl/411888056; Choudhury, S.; Christakoglou, P.; Christensen, C. H.; Christiansen, P.; Chujo, T.; Chung, S. U.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Colamaria, F.; Colella, D.; Collu, A.; Colocci, M.; Conesa Balbastre, G.; Conesa del Valle, Z.; Connors, M. E.; Contreras, J. G.; Cormier, T. M.; Corrales Morales, Y.; Cortés Maldonado, I.; Cortese, P.; Cosentino, M. R.; Costa, F.; Costanza, S.; Crkovská, J.; Crochet, P.; Cuautle, E.; Cunqueiro, L.; Dahms, T.; Dainese, A.; Danisch, M. C.; Danu, A.; Das, D.; Das, I.; Das, S.; Dash, A.; Dash, S.; Dasgupta, S. S.; De Caro, A.; De Cataldo, G.; De Conti, C.; De Cuveland, J.; De Falco, A.; De Gruttola, D.; De Marco, N.; De Pasquale, S.; De Souza, R. Derradi; Degenhardt, H. F.; Deisting, A.; Deloff, A.; Deplano, C.; Dhankher, P.; Di Bari, D.; Di Mauro, A.; Di Nezza, P.; Di Ruzza, B.; Diaz Corchero, M. A.; Dietel, T.; Dillenseger, P.; Divià, R.; Djuvsland, A.; Dobrin, A.|info:eu-repo/dai/nl/372618715; Domenicis Gimenez, D.; Dönigus, B.; Dordic, O.; Drozhzhova, T.; Dubey, A. K.; Dubla, A.|info:eu-repo/dai/nl/355502488; Ducroux, L.; Duggal, A. K.; Dupieux, P.; Ehlers, R. J.; Elia, D.; Endress, E.; Engel, H.; Epple, E.; Erazmus, B.; Erhardt, F.; Espagnon, B.; Esumi, S.; Eulisse, G.; Eum, J.; Evans, D.; Evdokimov, S.; Fabbietti, L.; Fabris, D.; Faivre, J.; Fantoni, A.; Fasel, M.; Feldkamp, L.; Feliciello, A.; Feofilov, G.; Ferencei, J.; Fernández Téllez, A.; Ferreiro, E. G.; Ferretti, A.; Festanti, A.; Feuillard, V. J. G.; Figiel, J.; Figueredo, M. A S; Filchagin, S.; Finogeev, D.; Fionda, F. M.; Fiore, E. M.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Francescon, A.; De Francisco, A.; Frankenfeld, U.; Fronze, G. G.; Fuchs, U.; Furget, C.; Furs, A.; Fusco Girard, M.; Gaardhøje, J. J.; Gagliardi, M.; Gago, A. M.; Gajdosova, K.; Gallio, M.; Galvan, C. D.; Gangadharan, D. R.; Ganoti, P.; Gao, C.; Garabatos, C.; Garcia-Solis, E.; Garg, K.; Garg, P.; Gargiulo, C.; Gasik, P.; Gauger, E. F.; Gay Ducati, M. B.; Germain, M.; Ghosh, P.; Ghosh, S. K.; Gianotti, P.; Giubellino, P.; Giubilato, P.; Gladysz-Dziadus, E.; Glässel, P.; Goméz Coral, D. M.; Gomez Ramirez, A.; Gonzalez, A. S.; Gonzalez, V; González-Zamora, P.; Gorbunov, S.; Görlich, L.; Gotovac, S.; Grabski, V.; Graczykowski, L. K.; Graham, K. L.; Gramling, J. L.; Greiner, L. C.; Grelli, A.|info:eu-repo/dai/nl/326052577; Grigoras, C.; Grigoriev, V.; Grigoryan, A.; Grigoryan, S.; Grion, N.; Gronefeld, J. M.; Grosa, F.; Grosse-Oetringhaus, J. F.; Grosso, R.; Gruber, L.; Grull, F. R.; Guber, F.; Guernane, R.; Guerzoni, B.; Gulbrandsen, K.; Gunji, T.; Gupta, A.; Gupta, R.; Guzman, I. B.; Haake, R.; Hadjidakis, C.; Hamagaki, H.; Hamar, G.; Hamon, J. C.; Harris, J. W.; Harton, A.; Hatzifotiadou, D.; Hayashi, S.; Heckel, S. T.; Hellbär, E.; Helstrup, H.; Herghelegiu, A.; Herrera Corral, G.; Herrmann, F.; Hess, B. A.; Hetland, K. F.; Hillemanns, H.; Hippolyte, B.; Hladky, J.; Horak, D.; Hosokawa, R.; Hristov, P.; Hughes, C.W.; Humanic, T. J.; Hussain, N.; Hussain, T.; Hutter, D.; Hwang, D. S.; Ilkaev, R.; Inaba, M.; Ippolitov, M.; Irfan, M.; Isakov, V.; Islam, M. S.; Ivanov, M.; Ivanov, V.; Izucheev, V.; Jacak, B.; Jacazio, N.; Jacobs, P. M.; Jadhav, M. B.; Jadlovska, S.; Jadlovsky, J.; Jahnke, C.; Jakubowska, M. J.; Janik, M. A.; Jayarathna, P. H S Y; Jena, C.; Jena, S.; Jercic, M.; Jimenez Bustamante, R. T.; Jones, P. G.; Jusko, A.; Kalinak, P.; Kalweit, A.; Kang, J. H.; Kaplin, V.; Kar, S.; Karasu Uysal, A.; Karavichev, O.; Karavicheva, T.; Karayan, L.; Karpechev, E.; Kebschull, U.; Keidel, R.; Keijdener, D. L.D.|info:eu-repo/dai/nl/370530780; Keil, M.; Ketzer, B.; Mohisin Khan, M.; Khan, P.M.; Khan, Shfaqat A.; Khanzadeev, A.; Kharlov, Y.; Khatun, A.; Khuntia, A.; Kielbowicz, M. M.; Kileng, B.; Kim, D. W.; Kim, D. J.; Kim, D.-S.; Kim, H.; Kim, J. S.; Kim, J.; Kim, M.; Kim, M.; Kim, S.; Kim, T.; Kirsch, S.; Kisel, I.; Kiselev, S.; Kisiel, A.; Kiss, G.; Klay, J. L.; Klein, C; Klein, J.; Klein-Bösing, C.; Klewin, S.; Kluge, A.; Knichel, M. L.; Knospe, A. G.; Kobdaj, C.; Kofarago, M.|info:eu-repo/dai/nl/371571227; Kollegger, T.; Kolojvari, A.; Kondratiev, V.; Kondratyeva, N.; Kondratyuk, E.; Konevskikh, A.; Kopcik, M.; Kour, M.; Kouzinopoulos, C.; Kovalenko, O.; Kovalenko, V.; Kowalski, M.L.; Koyithatta Meethaleveedu, G.; Králik, I.; Kravčáková, A.; Krivda, M.; Krizek, F.; Kryshen, E.; Krzewicki, M.|info:eu-repo/dai/nl/362845670; Kubera, A. M.; Kučera, V.; Kuhn, C.; Kuijer, P. G.|info:eu-repo/dai/nl/074064975; Kumar, A.; Kumar, J.; Kumar, L.; Kumar, S.; Kundu, Seema; Kurashvili, P.; Kurepin, A.; Kurepin, A. B.; Kuryakin, A.; Kushpil, S.; Kweon, M. J.; Kwon, Y.; La Pointe, S. L.|info:eu-repo/dai/nl/355080192; La Rocca, P.; Lagana Fernandes, C.; Lakomov, I.; Langoy, R.; Lapidus, K.; Lara, C.; Lardeux, A.; Lattuca, A.; Laudi, E.; Lavicka, R.; Lazaridis, L.; Lea, R.; Leardini, L.; Lee, S.; Lehas, F.|info:eu-repo/dai/nl/411295721; Strunz-Lehner, Christine; Lehrbach, J.; Lemmon, R. 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C.; Zaporozhets, S.; Zardoshti, N.; Zarochentsev, A.; Závada, P.; Zaviyalov, N.; Zbroszczyk, H.; Zhalov, M.; Zhang, H.; Zhang, X.; Zhang, Y.; Zhang, C.; Zhang, Z.; Zhao, C.; Zhigareva, N.; Zhou, D.; Zhou, Y.; Zhou, Z.; Zhu, H.; Zhu, J.; Zhu, X.; Zichichi, A.; Zimmermann, A.; Zimmermann, M. B.; Zimmermann, S.; Zinovjev, G.; Zmeskal, J.
2017-01-01
We present the first azimuthally differential measurements of the pion source size relative to the second harmonic event plane in Pb-Pb collisions at a center-of-mass energy per nucleon-nucleon pair of √sNN = 2.76 TeV. The measurements have been performed in the centrality range 0%-50% and for pion
Mac Raighne, A; Crossley, M; Alianelli, L; Lozano, M; Dumps, R; Fleta, C; Collins, P; Rodrigues, E; Sawhney, K J S; Tlustos, L; Pennicard, D; Buytaert, J; Stewart, G; Parkes, C; Eklund, L; Campbell, M; Marchal, J; Akiba, K; Pellegrini, G; Llopart, X; Plackett, R; Maneuski, D; Gligorov, V V; Tartoni, N; Nicol, M; Bates, R; Gallas, A; Gimenez, E N; van Beuzekom, M; John, M
2011-01-01
Three-dimensional (3D) silicon sensors offer potential advantages over standard planar sensors for radiation hardness in future high energy physics experiments and reduced charge-sharing for X-ray applications, but may introduce inefficiencies due to the columnar electrodes. These inefficiencies are probed by studying variations in response across a unit pixel cell in a 55 m m pitch double-sided 3D pixel sensor bump bonded to TimePix and Medipix2 readout ASICs. Two complementary characterisation techniques are discussed: the first uses a custom built telescope and a 120GeV pion beam from the Super Proton Synchrotron (SPS) at CERN; the second employs a novel technique to illuminate the sensor with a micro-focused synchrotron X-ray beam at the Diamond Light Source, UK. For a pion beam incident perpendicular to the sensor plane an overall pixel efficiency of 93.0 +/- 0.5\\% is measured. After a 10 degrees rotation of the device the effect of the columnar region becomes negligible and the overall efficiency rises ...