Is the quasielastic pion cross section really bigger than the pion-nucleus reaction cross section
International Nuclear Information System (INIS)
Silbar, R.R.
1979-01-01
It is shown that soft pion charge exchanges may increase the inclusive (π + ,π 0 ') cross section, relative to the total quasielastic (π + ,π + ') cross section, by as much as a factor of two. 4 references
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
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
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
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
Mid-rapidity pion cross sections: new data confront theories
International Nuclear Information System (INIS)
Frankel, K.A.; Bistirlich, J.A.; Bossingham, R.
1981-07-01
Pion production by collisions of relativistic heavy ions has been studied recently by Wolf et al. For the reaction 1.05 GeV/A 40 Ar + Ca → π + , they discovered a peak in the invariant cross section at mid-rapidity at P/sub perpendicular/ approx. 0.5 m/sub π/c. This peak is not apparent in the 730 MeV p + p data of Cochran et al. and was attributed to possible hydrodynamic flow effects. Several authors have suggested that the π + peak is a Coulomb effect. These models predict the π - would be drawn in towards the fireball, leaving an essentially flat distribution in the mid-rapidity region. Mid-rapidity π + and π - cross sections were measured using a 1.05 GeV/A argon beam with a calcium target. The pions were measured with a magnetic spectrometer set at 15 0 to the beam and were stopped in a scintillator range telescope. Results are presented and discussed
Muon-neutrino-induced charged-current cross section without pions: Theoretical analysis
Mosel, U.; Gallmeister, K.
2018-04-01
We calculate the charged-current cross sections obtained at the T2K near detector for νμ-induced events without pions in the final state. The method used is quantum-kinetic transport theory. Results are shown first, as a benchmark, for electron-inclusive cross sections on 12C and 16O to be followed with a detailed comparison with the data measured by the T2K Collaboration on C8H8 and H2O targets. The contribution of 2p2h processes is found to be relevant mostly for backward angles; their theoretical uncertainties are within the experimental uncertainties. Particular emphasis is then put on a discussion of events in which pions are first created but then reabsorbed. Their contribution is found to be essential at forward angles.
Parameterization of pion production and reaction cross sections at LAMPF energies
International Nuclear Information System (INIS)
Burman, R.L.; Smith, E.S.
1989-05-01
A parameterization of pion production and reaction cross sections is developed for eventual use in modeling neutrino production by protons in a beam stop. Emphasis is placed upon smooth parameterizations for proton energies up to 800 MeV, for all pion energies and angles, and for a wide range of materials. The resulting representations of the data are well-behaved and can be used for extrapolation to regions where there are no measurements. 22 refs., 16 figs., 2 tabs
International Nuclear Information System (INIS)
Ivanov, A.N.; Antonov, M.V.; Barbaro, J.A.; Caballero, G.A.; Megias, G.D.; González-Jiménez, R.; Giusti, C.; Meucci, A.; Moya de Guerra, E.; Udías, J.M.
2015-01-01
Superscaling approximation (SuSA) predictions to neutrino-induced charged-current pion production in the Δ-resonance region are explored under MiniBooNE experimental conditions. The results obtained within SuSA for the flux-averaged double-differential cross sections of the pion production for the ν_μ+CH_2 reaction as a function of the muon kinetic energy and of the scattering angle, the cross sections averaged over the angle, the total cross section for the pion production are compared with the corresponding MiniBooNE experimental data. The SuSA charged-current π"+ predictions are in good agreement with data on neutrino flux average cross-sections. The SuSA extension to the pion production region and the realistic spectral function S(p;ε) for quasielastic scattering are used for predictions of charged current inclusive neutrino-nucleus cross sections. The results are compared with the inclusive neutrino-nucleus data from the T2K experiment. (author)
Total pion cross section measurements. Annual progress report, 1 January 1977--31 December 1978
International Nuclear Information System (INIS)
Jakobson, M.J.; Jeppesen, R.H.
1978-01-01
The pion-nucleus total cross section runs were completed. The principal effort for the past year has been devoted to data analysis. The experiment was primarily designed to provide an accurate measurement of total cross section differences for pairs of isotopes. Data were published on neutron radii of calcium isotopes and on pion cross section measurements for aligned holmium. The π+- data to be published include targets and energies for 4 He, 23 → 90 MeV; 12 C, 13 C, 23 → 240 MeV; 6 Li, 7 Li, 9 Be, 10 B, 11 B, 43 → 215 MeV; 16 O, 18 O, 40 Ca, 44 Ca, 48 Ca, 43 → 240 MeV; 45 Sc, 51 V, Al, Cu, Sn, Ho, Pb, 60 → 215 MeV
Pion production differential cross section of heavy-ion collisions at subthreshold energies
International Nuclear Information System (INIS)
Abumurad, K.M.
1987-01-01
A revised model for pion production in heavy-ion peripheral collisions at subthreshold energies is presented. The pion-production mechanism investigated here is a two step process involving the formation and subsequent decay of an isobar resonance in the projectile nucleus. The independent-particle shell model with harmonic oscillator states is used to approximate the internal structure of the nucleus. The pion production cross section shows a definite angular distribution characteristic of coherent production. It also gives an indication of the quantum signature of the emitted pions. The results show the disappearance of the quantum signature from the energy spectra because of the inclusion of higher order multipoles. The theory is compared to recent experimental data. The comparison reveals that the general trend is reproduced, which is encouraging
International Nuclear Information System (INIS)
Deutchman, P.A.; Norbury, J.W.; Townsend, L.W.
1985-01-01
A quantal many-body formalism is presented that investigates pion production through the coherent formation of a nucleonic isobar in the projectile and its subsequent decay to various pion charge states along with concomitant excitation of the target to a coherent spin-isospin giant resonance via a peripheral collision of relativistic heavy ions. Total cross sections as a function of the incident energy per nucleon and Lorentz-invariant differential cross sections as a function of pion energy and angle are calculated. It is shown that the pion angular distributions, in coincidence with the target giant resonance excitations, might provide a well-defined signature for these coherent processes
Study of fission cross sections induced by nucleons and pions using the cascade-exciton model CEM95
International Nuclear Information System (INIS)
Yasin, Z.; Shahzad, M. I.
2007-01-01
Nucleon and pion-induced fission cross sections at intermediate and at higher energies are important in current nuclear applications, such as accelerator driven-systems (ADS), in medicine, for effects on electronics etc. In the present work, microscopic fission cross sections induced by nucleons and pions are calculated using the cascade-exciton model code CEM95 for different projectile-target combinations; at various energies and the computed cross sections are compared with the experimental data found in literature. A new approach is used to compute the fission cross sections in which a change of the ratio of the level density parameter in fission to neutron emission channels was taken into account with the change in the incident energy of the projectile. We are unable to describe well the fission cross sections without using this new approach. Proton induced fission cross sections are calculated for targets 1 97Au, 2 08Pb, 2 09Bi, 2 38U and 2 39Pu in the energy range from 20 MeV to 2000 MeV. Neutron induced fission cross sections are computed for 2 38U and 2 39Pu in the energy range from 20 MeV to 200 MeV. Negative pion induced cross sections for fission are calculated for targets 1 97Au and 2 08Pb from 50 MeV to 2500 MeV energy range. The calculated cross sections are essential to build a data library file for accelerator driven systems just like was built for conventional nuclear reactors. The computed values exhibited reasonable agreement with the experimental values found in the literature across a wide range of beam energies
Pion-nucleus total cross sections in the (3, 3) resonance region
International Nuclear Information System (INIS)
Carroll, A.S.; Chiang, I.; Dover, C.B.; Kycia, T.F.; Li, K.K.; Mazur, P.O.; Michael, D.N.; Mockett, P.M.; Rahm, D.C.; Rubinstein, R.
1976-01-01
The results of total cross section measurements are presented for π +- on targets of natural Li, C, Al, Fe, Sn, and Pb in the region of 65--320 MeV laboratory kinetic energy. The data are fitted with a simple phenomenological model, which allows one to extract the A dependence of the peak energy and the width which characterize the pion-nucleus interaction
SHIELD and HZETRN comparisons of pion production cross sections
Norbury, John W.; Sobolevsky, Nikolai; Werneth, Charles M.
2018-03-01
A program of comparing American (NASA) and Russian (ROSCOSMOS) space radiation transport codes has recently begun, and the first paper directly comparing the NASA and ROSCOSMOS space radiation transport codes, HZETRN and SHIELD respectively has recently appeared. The present work represents the second time that NASA and ROSCOSMOS calculations have been directly compared, and the focus here is on models of pion production cross sections used in the two transport codes mentioned above. It was found that these models are in overall moderate agreement with each other and with experimental data. Disagreements that were found are discussed.
Measurements of Cross Sections and Charged Pion Spectra in Proton-Carbon Interactions at 31 GeV/c
Abgrall, N; Andrieu, B; Anticic, T; Antoniou, N; Argyriades, J; Asryan, A G; Baatar, B; Blondel, A; Blumer, J; Bogusz, M; Boldizsar, L; Bravar, A; Brooks, W; Brzychczyk, J; Bubak, A; Bunyatov, S A; Busygina, O; Cetner, T; Choi, K -U; Christakoglou, P; Chung, P; Czopowicz, T; Davis, N; Diakonos, F; Di Luise, S; Dominik, W; Dumarchez, J; Engel, R; Ereditato, A; Esposito, L S; Feofilov, G A; Fodor, Z; Ferrero, A; Fulop, A; Garrido, X; Gazdzicki, M; Golubeva, M; Grebieszkow, K; Grzeszczuk, A; Guber, F; Hakobyan, H; Hasegawa, T; Igolkin, S; Ivanov, A S; Ivanov, Y; Ivashkin, A; Kadija, K; Kapoyannis, A; Katrynska, N N; Kielczewska, D; Kikola, D; Kim, J -H; Kirejczyk, M; Kisiel, J; Kobayashi, T; Kochebina, O; Kolesnikov, V I; Kolev, D; Kondratiev, V P; Korzenev, A; Kowalski, S; Kuleshov, S; Kurepin, A; Lacey, R; Lagoda, J; Laszlo, A; Lyubushkin, V V; Mackowiak, M; Majka, Z; Malakhov, A I; Marchionni, A; Marcinek, A; Maris, I; Marin, V; Matulewicz, T; Matveev, V; Melkumov, G L; Meregaglia, A; Messina, M; Mrowczynski, St; Murphy, S; Nakadaira, T; Naumenko, P A; Nishikawa, K; Palczewski, T; Palla, G; Panagiotou, A D; Peryt, W; Petukhov, O; Planeta, R.; Pluta, J; Popov, B A; Posiadala, M; Pu lawski, S; Rauch, W; Ravonel, M; Renfordt, R; Robert, A; Rohrich, D; Rondio, E; Rossi, B; Roth, M; Rubbia, A; Rybczynski, M; Sadovsky, A; Sakashita, K; Sekiguchi, T; Seyboth, P; Shibata, M; Sissakian, A N; Skrzypczak, E; Slodkowski, M.; Sorin, A S; Staszel, P; Stefanek, G; Stepaniak, J; Strabel, C; Strobele, H; Susa, T; Szaik, P; Szuba, M; Tada, M; Taranenko, A; Tsenov, R; Ulrich, R; Unger, M; Vassiliou, M; Vechernin, V V; Vesztergombi, G; Wilczek, A; lodarczyk, Z W; Wojtaszek, A; Yi, J -G; Yoo, I -K; Zipper, W
2011-01-01
Interaction cross sections and charged pion spectra in p+C interactions at 31 GeV/c were measured with the large acceptance NA61/SHINE spectrometer at the CERN SPS. These data are required to improve predictions of the neutrino flux for the T2K long baseline neutrino oscillation experiment in Japan. A set of data collected during the first NA61/SHINE run in 2007 with an isotropic graphite target with a thickness of 4% of a nuclear interaction length was used for the analysis. The measured p+C inelastic and production cross sections are 257.2 +- 1.9 +- 8.9 mb and 229.3 +- 1.9 +- 9.0 mb, respectively. Inclusive production cross sections for negatively and positively charged pions are presented as a function of laboratory momentum in 10 intervals of the laboratory polar angle covering the range from 0 up to 420 mrad. The spectra are compared with predictions of several hadron production models.
Martini, M; G. Chanfray; Marteau, J
2010-01-01
Neutrino-nucleus cross-sections are needed to interpret neutrino oscillation data, as neutrino detectors involve complex nuclei. We present a theory of neutrino interactions with nuclei aimed at a unified description of the partial cross-sections, namely quasi-elastic and multi-nucleon emission, coherent and incoherent single pion production. We compare our approach to the available neutrino experimental data on carbon. We also discuss the evolution of the neutrino cross-sections with the mass number in view of future precision ex- periments which will use a liquid argon chamber.
Energy Technology Data Exchange (ETDEWEB)
Wickremasinghe, Don Athula Abeyarathna [Univ. of Cincinnati, OH (United States)
2015-07-01
The prediction of the muon neutrino flux from a 71.0 cm long beryllium target for the MiniBooNE experiment is based on a measured pion production cross section which was taken from a short beryllium target (2.0 cm thick - 5% nuclear interaction length) in the Hadron Production (HARP) experiment at CERN. To verify the extrapolation to our longer target, HARP also measured the pion production from 20.0 cm and 40.0 cm beryllium targets. The measured production yields, d^{2}N^{π±} (p; θ )=dpd Ω, on targets of 50% and 100% nuclear interaction lengths in the kinematic rage of momentum from 0.75 GeV/c to 6.5 GeV/c and the range of angle from 30 mrad to 210 mrad are presented along with an update of the short target cross sections. The best fitted extended Sanford-Wang (SW) model parameterization for updated short beryllium target π^{+} production cross section is presented. Yield measurements for all three targets are also compared with that from the Monte Carlo predictions in the MiniBooNE experiment for different SW parameterization. The comparisons of v_{μ} flux predictions for updated SW model is presented.
Measurement of muon neutrino and antineutrino induced single neutral pion production cross sections
Energy Technology Data Exchange (ETDEWEB)
Anderson, Colin E. [Yale Univ., New Haven, CT (United States)
2011-05-01
Elucidating the nature of neutrino oscillation continues to be a goal in the vanguard of the efforts of physics experiment. As neutrino oscillation searches seek an increasingly elusive signal, a thorough understanding of the possible backgrounds becomes ever more important. Measurements of neutrino-nucleus interaction cross sections are key to this understanding. Searches for ν_{μ} → ν_{e} oscillation - a channel that may yield insight into the vanishingly small mixing parameter θ_{1}3, CP violation, and the neutrino mass hierarchy - are particularly susceptible to contamination from neutral current single π^{0} (NC 1π^{0}) production. Unfortunately, the available data concerning NC 1π^{0} production are limited in scope and statistics. Without satisfactory constraints, theoretical models of NC 1π^{0} production yield substantially differing predictions in the critical E_{ν} ~ 1 GeV regime. Additional investigation of this interaction can ameliorate the current deficiencies. The Mini Booster Neutrino Experiment (MiniBooNE) is a short-baseline neutrino oscillation search operating at the Fermi National Accelerator Laboratory (Fermilab). While the oscillation search is the principal charge of the MiniBooNE collaboration, the extensive data (~ 10^{6} neutrino events) offer a rich resource with which to conduct neutrino cross section measurements. This work concerns the measurement of both neutrino and antineutrino NC 1π^{0} production cross sections at MiniBooNE. The size of the event samples used in the analysis exceeds that of all other similar experiments combined by an order of magnitude. We present the first measurements of the absolute NC 1π^{0} cross section as well as the first differential cross sections in both neutrino and antineutrino mode. Specifically, we measure single differential cross sections with respect to pion momentum and pion angle. We find the
Asymptotic behaviour of pion-pion total cross-sections
Energy Technology Data Exchange (ETDEWEB)
Greynat, David [Dipartimento di Scienze Fisiche, Universita di Napoli “Federico II”,Via Cintia, 80126 Napoli (Italy); Rafael, Eduardo de [Aix-Marseille Université, CNRS,CPT, UMR 7332, 13288 Marseille (France); Université de Toulon, CNRS,CPT, UMR 7332, 83957 La Garde (France); Vulvert, Grégory [Departament de Física Teórica, IFIC,CSIC - Universitat de València, Apt. Correus 22085, E-46071 València (Spain)
2014-03-24
We derive a sum rule which shows that the Froissart-Martin bound for the asymptotic behaviour of the ππ total cross sections at high energies, if modulated by the Lukaszuk-Martin coefficient of the leading log{sup 2} s behaviour, cannot be an optimal bound in QCD. We next compute the total cross sections for π{sup +}π{sup −}, π{sup ±}π{sup 0} and π{sup 0}π{sup 0} scattering within the framework of the constituent chiral quark model (CχQM) in the limit of a large number of colours N{sub c} and discuss their asymptotic behaviours. The same ππ cross sections are also discussed within the general framework of Large-N{sub c} QCD and we show that it is possible to make an Ansatz for the isospin I=1 and I=0 spectrum which satisfy the Froissart-Martin bound with coefficients which, contrary to the Lukaszuk-Martin coefficient, are not singular in the chiral limit and have the correct Large-N{sub c} counting. We finally propose a simple phenomenological model which matches the low energy behaviours of the σ{sub π{sup ±}π{sup 0total}}(s) cross section predicted by the CχQM with the high energy behaviour predicted by the Large-N{sub c} Ansatz. The magnitude of these cross sections at very high energies is of the order of those observed for the pp and pp-bar scattering total cross sections.
Asymptotic behaviour of pion-pion total cross-sections
International Nuclear Information System (INIS)
Greynat, David; Rafael, Eduardo de; Vulvert, Grégory
2014-01-01
We derive a sum rule which shows that the Froissart-Martin bound for the asymptotic behaviour of the ππ total cross sections at high energies, if modulated by the Lukaszuk-Martin coefficient of the leading log 2 s behaviour, cannot be an optimal bound in QCD. We next compute the total cross sections for π + π − , π ± π 0 and π 0 π 0 scattering within the framework of the constituent chiral quark model (CχQM) in the limit of a large number of colours N c and discuss their asymptotic behaviours. The same ππ cross sections are also discussed within the general framework of Large-N c QCD and we show that it is possible to make an Ansatz for the isospin I=1 and I=0 spectrum which satisfy the Froissart-Martin bound with coefficients which, contrary to the Lukaszuk-Martin coefficient, are not singular in the chiral limit and have the correct Large-N c counting. We finally propose a simple phenomenological model which matches the low energy behaviours of the σ π ± π 0 total (s) cross section predicted by the CχQM with the high energy behaviour predicted by the Large-N c Ansatz. The magnitude of these cross sections at very high energies is of the order of those observed for the pp and pp-bar scattering total cross sections
Low Energy Neutrino Cross Sections
International Nuclear Information System (INIS)
Zeller, G.P.
2004-01-01
Present atmospheric and accelerator based neutrino oscillation experiments operate at low neutrino energies (Ev ∼ 1 GeV) to access the relevant regions of oscillation parameter space. As such, they require precise knowledge of the cross sections for neutrino-nucleon interactions in the sub-to-few GeV range. At these energies, neutrinos predominantly interact via quasi-elastic (QE) or single pion production processes, which historically have not been as well studied as the deep inelastic scattering reactions that dominate at higher energies.Data on low energy neutrino cross sections come mainly from bubble chamber, spark chamber, and emulsion experiments that collected their data decades ago. Despite relatively poor statistics and large neutrino flux uncertainties, these measurements provide an important and necessary constraint on Monte Carlo models in present use. The following sections discuss the current status of QE, resonant single pion, coherent pion, and single kaon production cross section measurements at low energy
Measurement of the elastic cross section for positive pions on carbon at 142 MeV
International Nuclear Information System (INIS)
Oyer, A.T.
1976-12-01
A measurement of the elastic cross section dsigma/dΩ was made for the reaction π + + 12 C → π + + 12 C with 142 MeV pions at ten angles ranging from 35 to 85 0 in the laboratory. This experiment was done at the Los Alamos Meson Physics Facility. A double focusing magnetic spectrometer observed a cylindrical styrofoam target. The resulting momentum spectra were recorded by an array of nineteen totally depleted surface barrier detectors located at the spectrometer's focal plane. The spectra from the styrofoam were composed of peaks representing proton elastic, carbon elastic, carbon inelastic, and carbon quasi-elastic channels. A function made of Gaussians representing the two body channels and a distribution representing the quasi-elastic channel was fit to the data using a nonlinear least squares algorithm. The ratio of the carbon elastic to proton elastic cross sections was calculated from the areas of the corresponding Gaussians and then multiplied by the proton elastic cross section of Bugg et al eliminating several sources of systematic errors such as beam normalization. The differential cross sections were found to have the usual diffraction structure with a forward peak and a minimum near 55 0 . Finally, the carbon elastic cross sections were compared to similar π - + 12 C cross sections of Binon et al using the optical model
Measurement of the elastic cross section for positive pions on carbon at 142 MeV
Energy Technology Data Exchange (ETDEWEB)
Oyer, A.T.
1976-12-01
A measurement of the elastic cross section dsigma/d..cap omega.. was made for the reaction ..pi../sup +/ + /sup 12/C ..-->.. ..pi../sup +/ + /sup 12/C with 142 MeV pions at ten angles ranging from 35 to 85/sup 0/ in the laboratory. This experiment was done at the Los Alamos Meson Physics Facility. A double focusing magnetic spectrometer observed a cylindrical styrofoam target. The resulting momentum spectra were recorded by an array of nineteen totally depleted surface barrier detectors located at the spectrometer's focal plane. The spectra from the styrofoam were composed of peaks representing proton elastic, carbon elastic, carbon inelastic, and carbon quasi-elastic channels. A function made of Gaussians representing the two body channels and a distribution representing the quasi-elastic channel was fit to the data using a nonlinear least squares algorithm. The ratio of the carbon elastic to proton elastic cross sections was calculated from the areas of the corresponding Gaussians and then multiplied by the proton elastic cross section of Bugg et al eliminating several sources of systematic errors such as beam normalization. The differential cross sections were found to have the usual diffraction structure with a forward peak and a minimum near 55/sup 0/. Finally, the carbon elastic cross sections were compared to similar ..pi../sup -/ + /sup 12/C cross sections of Binon et al using the optical model.
Measurement of the elastic cross section for positive pions on carbon at 142 MeV
International Nuclear Information System (INIS)
Oyer, A.T.
1976-01-01
A measurement of the elastic cross section dsigma/dOMEGA was made for the reaction π + + 12 C yields π + + 12 C with 142 MeV pions at ten angles ranging from 35 to 85 0 in the laboratory. This experiment was done at the Los Alamos Meson Physics Facility. A double focusing magnetic spectrometer observed a cylindrical styrofoam target. The resulting momentum spectra were recorded by an array of nineteen totally depleted surface barrier detectors located at the spectrometers focal plane. The spectra from the styrofoam were composed of peaks representing proton elastic, carbon elastic, carbon inelastic and carbon quasi-elastic channels. A function made of Gaussians representing the two body channels and a distribution representing the quasi-elastic channel was fit to the data using a nonlinear least squares algorithm. The ratio of the carbon elastic to proton elastic cross sections was calculated from the areas of the corresponding Gaussians and then multiplied by the proton elastic cross section of Bugg et al., eliminating several sources of systematic errors such as beam normalization. The differential cross sections were found to have the usual diffraction structure with a forward peak and a minimum near 55 0 . Finally, the carbon elastic cross sections were compared to similar π - + 12 C cross sections of Binon et al., using the optical model
Progress of the Charged Pion Semi-Inclusive Neutrino Charged Current Cross Section in NOvA
Energy Technology Data Exchange (ETDEWEB)
Tsaris, Aristeidis [Fermilab
2017-10-09
The NOvA experiment is a long-baseline neutrino oscillation experiment designed to measure the rates of electron neutrino appearance and muon neutrino disappearance. The NOvA near detector is located at Fermilab, 800 m from the primary target and provides an excellent platform to measure and study neutrino-nucleus interactions. We present the status of the measurement of the double differential cross section with respect to muon kinematics for interactions involving charged pions in the final state, $\
International Nuclear Information System (INIS)
Barashenkov, V.S.
1990-01-01
The tables of inelastic and total cross sections of π ± mesons interactions with nuclei 4 He- 238 U are presented. The tables are obtained by theoretical analysis of known experimental data for energies higher some tens of MeV. 1 ref.; 1 tab
International Nuclear Information System (INIS)
Angelov, N.; Ahababyan, N.; Anoshin, A.I.
1979-01-01
Data are presented on inelastic cross sections and multiplicities of pions minus produced on collisions of protons, deuterons, helium-4 and carbon-12 nuclei at 4.2 GeV/c per nucleon in the propane bubble chamber witn tantalum and carbon plates. Average multiplicities and dispersions of multiplicity distributions are compared with those in nucleon-nucleon interactions. Deviation of C-Ta interaction data from universal dependence of dispersion on multiplicity is observed. Pion multiplicities are found proportional to the number of nucleons from incident nucleus which interacted in the target. The results are not in contradiction with the assumption that nucleons from the incident nucleus interact independently in the target. For C-Ta interactions the average radius of the pion emission volume has been determined by the interference method to be r=(3.3+-0.6) fm
Abe, K.
2017-01-26
The T2K off-axis near detector, ND280, is used to make the first differential cross section measurements of muon neutrino charged current single positive pion production on a water target at energies ${\\sim}0.8$~GeV. The differential measurements are presented as a function of muon and pion kinematics, in the restricted phase-space defined by $p_{\\pi^+}>200$MeV/c, $p_{\\mu^-}>200$MeV/c, $\\cos \\theta_{\\pi^+}>0.3$ and $\\cos \\theta_{\\mu^-}>0.3$. The total flux integrated $\
International Nuclear Information System (INIS)
Laveissiere, G.
2001-11-01
In hadronic physics, the nucleon structure and the quarks confinement are still topical issues. The neutral pion electroproduction and virtual Compton scattering (VCS) reactions allow us to access new observables that describe this structure. This work is focussed on the VCS experiment performed at Jefferson Lab in 1998. The 4 GeV electron beam is scattered off a cryogenic hydrogen target, and the scattered electron and recoiled proton are detected in coincidence in the twin hall A spectrometers. The photon (pion) is reconstructed using a missing particle technique. The data analysis allowed to extract the cross sections relative to both process at four-momentum transfer squared Q 2 = 1 GeV 2 . The VCS cross section has been extracted for the first time in the proton resonance region (W between 1.O and 2.0 GeV) through the photon electroproduction reaction. Around the pion-production threshold up to the Delta(1232) resonance region, these results lead to the measurement of the generalized polarizabilities, that describe the proton structure in the same way as the elastic form factors. Moreover, the neutral pion electroproduction cross section measurement in the resonance region has brought new constraints on the existing phenomenological models. (author)
International Nuclear Information System (INIS)
Guertin, A.
2001-01-01
A charged kaon includes a strange anti-quark that cannot be re-absorbed by matter which make kaons an interesting probe of nuclear matter. The first part of this work is dedicated to the production cross-sections of pions and kaons in proton-nucleus collision around 1 GeV. The molecular quantum dynamic model used for simulating proton-nucleus is presented and the total cross-sections of the reactions implemented in the model are described. Then, the impact of the neutron's spectral function on pion and kaon production is assessed in double differential cross-sections. The consequences of the correlations observed between nucleons are discussed. The simple phenomenological approach we have developed to take into account 2 nucleon correlations gives good results for the doubly differential production cross-section of pions and kaons whatever the target nucleus. The second part of this work is dedicated to the measurement of the production of light charged particles (p, d, t, "3He, α) and neutron production in collisions between 62,9 MeV protons with "2"0"8Pb nuclei. The experimental setting is installed on the S2 line of the CYCLONE cyclotron (Belgium), the detection system is composed of 7 triple telescopes (Si, Si and CsI(Tl)). The separation and identification of particles is made through 2 methods: the E-ΔE method based on the energy losses in the different detectors and the discrimination method based on the different shapes of the quick and slow signals of the CsI crystal. The extraction of the cross-section values is detailed. We have compared the values obtained with 3 theoretical models: the exciton model (GNASH code), the F.K.K. (Feshbach-Kerman-Koonin) theory (MINGUS code) and a more phenomenological model able to simulate hadron reactions on nuclei for a very broad range of energy (FLUKA code)
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.
Near-threshold charged pion photoproduction from 13C
International Nuclear Information System (INIS)
LeRose, J.J.
1981-01-01
Differential cross sections to discrete final states have been measured for both positive and negative pion photo-production on 13 C at 90 0 in the lab at pion energies of 18, 29, and 41 MeV. Measurements were made using a fixed angle magnetic spectrometer located in the 14 0 area of the MIT Bates linear accelerator. Pions were detected using a 90 channel multi-wire proportional counter in the focal plane along with a backup array consisting of three 1/16'' thick plastic scintillator detectors and a 1/2'' thick Cerenkov detector. Positive pion photo-production cross sections were obtained for the excitation of the 3/2 - ground state and for the 3.45 MeV first excited state of 13 B. Negative pion photo-production cross sections were obtained for the excitation of the 1/2 - ground state, and the 3/2 to 3.51 MeV and 5/2 to 7.39 MeV excited states of 13 N. The measured positive pion photo-production ground state cross sections are in reasonable agreement wth theoretical calculations. However, there is a large discrepancy between the measured negative pion photoproduction ground state cross sections and the theoretical values. There are no theoretical calculations available for comparison with the excited state measurements in either positive or negative pion photoproduction on 13 C
Longitudinal Electroproduction of Charged Pions from
International Nuclear Information System (INIS)
David Gaskell; Abdellah Ahmidouch; Pawel Ambrozewicz; H. Anklin; John Arrington; K. Assamagan; Steven Avery; Kevin Bailey; Oliver K. Baker; Shelton Beedoe; Elizabeth Beise; Herbert Breuer; D. S. Brown; Roger Carlini; Jinseok Cha; Nicholas Chant; Anthony Cowley; Samuel Danagoulian; D. De Schepper; Jim Dunne; Dipangkar Dutta; Rolf Ent; Liping Gan; Ashot Gasparian; Donald Geesaman; Ron Gilman; Charles Glashausser; Paul Gueye; M. Harvey; O. Hashimoto; Wendy Hinton; G. Hofman; Ceasar Jackson; Hal Jackson; Cynthia Keppel; Ed Kinney; Doug Koltenuk; G. Kyle; Allison Lung; David Mack; D. McKee; Joseph Mitchell; Hamlet Mkrtchyan; B. Mueller; Gabriel Niculescu; Ioana Niculescu; Tom O'Neill; V. Papavassiliou; Dave Potterveld; Juerg Reinhold; Philip Roos; Reyad Sawafta; Ralph Segel; Stepan Stepanyan; Vardan Tadevosyan; T. Takahashi; Liguang Tang; B. Terburg; D. Van Westrum; J. Volmer; T. P. Welch; Stephen Wood; Lulin Yuan; Ben Zeidman; Beni Zihlmann
2001-01-01
Separated longitudinal and transverse cross sections for charged pion electroproduction from 1 H, 2 H, and 3 He were measured at Q 2 = 0.4 (GeV/c) 2 for two values of the invariant mass, (bar W) = 1.15 GeV and (bar W) = 1.60 GeV, in a search for a mass dependence which would signal the effect of nuclear pions. This is the first such study that includes recoil momenta significantly above the Fermi surface. The longitudinal cross section, if dominated by the pion-pole process, should be sensitive to nuclear pion currents. Comparisons of the longitudinal cross section target ratios to a quasifree calculation reveal a significant suppression in 3> He at (bar W) = 1.60 GeV. The (bar W) = 1.15 GeV results are consistent with simple estimates of the effect of nuclear pion currents, but are also consistent with pure quasifree production
To the calculation of differential and total cross sections of γπ interactions
International Nuclear Information System (INIS)
Duplij, S.A.
1980-01-01
The differential and total cross sections of different charge channels of the γπ→ππ process are calculated. At the threshold energies the vector dominance model predicts twice as large values of the total cross sections than the current algebra. In resonance the total cross section of photoproduction on a neutral pion is 10-50 μb, on a charged pion - 5-10μb, at near-threshold energies (Esub(γ)=300-600 MeV) both cross sections are of the 20-40 nb order. For the γπ→ππ process the differential cross sections according to the invariant mass of two pions are obtained for different charge channels. At the threshold energies the total cross sections of the γπ→ππ process is of the 0.1-1 nb order
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)
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
Radiative pion-proton scattering
International Nuclear Information System (INIS)
Ho-Kim, Q.; Lavine, J.P.
1977-01-01
The results are presented of a non-relativistic calculation of the π +- proton bremsstrahlung cross section at the pion kinetic energy of 298 MeV for backward photon angles. The pion-nucleon interaction is given by models that are based on the p-wave Chew-Low theory. An interaction current is included in an attempt to make the overall bremsstrahlung amplitude gauge-invariant. The predicted cross sections show little of the expected resonance, and are in fair agreement with the data. The authors have also calculated the cross sections at other kinetic energies, and have studied effects of the off-mass-shell electromagnetic vertex. (Auth.)
Energy Technology Data Exchange (ETDEWEB)
Laveissiere, G
2001-11-01
In hadronic physics, the nucleon structure and the quarks confinement are still topical issues. The neutral pion electroproduction and virtual Compton scattering (VCS) reactions allow us to access new observables that describe this structure. This work is focussed on the VCS experiment performed at Jefferson Lab in 1998. The 4 GeV electron beam is scattered off a cryogenic hydrogen target, and the scattered electron and recoiled proton are detected in coincidence in the twin hall A spectrometers. The photon (pion) is reconstructed using a missing particle technique. The data analysis allowed to extract the cross sections relative to both process at four-momentum transfer squared Q{sup 2} = 1 GeV{sup 2}. The VCS cross section has been extracted for the first time in the proton resonance region (W between 1.O and 2.0 GeV) through the photon electroproduction reaction. Around the pion-production threshold up to the Delta(1232) resonance region, these results lead to the measurement of the generalized polarizabilities, that describe the proton structure in the same way as the elastic form factors. Moreover, the neutral pion electroproduction cross section measurement in the resonance region has brought new constraints on the existing phenomenological models. (author)
Quantum signature in heavy-ion pion production
International Nuclear Information System (INIS)
Buvel, R.L.
1985-01-01
A revised model for pion production in heavy-ion peripheral collisions is presented. The pion-production mechanism investigated here is a two step process involving the formation and subsequent decay of an isobar resonance in the projectile nucleus. The independent-particle shell model with harmonic oscillator states is used to approximate the internal structure of the nucleus. The inclusion of the internal structure of the projectile nucleus led to the discovery of a quantum signature in the pion-production differential cross section. The quantum signature involves a matching condition where the pion-production differential cross section goes to zero for a particular value of the pion kinetic energy. The theory is compared to a recent experiment, but the results of this comparison are inconclusive
Single-meson inclusive cross sections and sequential decay of Reggeons, 2
Energy Technology Data Exchange (ETDEWEB)
Yoshida, Toshihiro
1984-09-01
The single-particle inclusive cross sections of pions and kaons produced from the incident particles in pp and anti pp scattering is investigated under the assumption of the sequential decay mechanism of Reggeons. The many-particle production effect and the initial-decay effect are estimated from experimental data on pion production cross section with small momentum transfer at 100 and 175 GeV/c. Their Feynman-x dependence is in good agreement with the power-law behaviours C(1-X sub(F))/sup 5/ and C(1-X sub(F))/sup 3/. Predictions are given on kaon production cross section.
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 photoproduction cross section at large momentum transfer
Energy Technology Data Exchange (ETDEWEB)
Sjoegren, Johan [Univ. of Glasgow, Scotland, United Kingdom
2015-02-27
The Real Compton Scattering experiment was performed in Hall A at the Thomas Jefferson National Accelerator Facility. It was designed to measure, for Compton scattering and π^{0}-photoproduction, the differential cross section over a range of kinematic points and the polarisation transfer to the proton at a single kinematic point. The full range of the experiment in Mandelstam variables t and s was 1.6-6.46 GeV^{2} and 4.82-10.92 GeV^{2} respectively with beam energies of 2-6 GeV. The motivation for the experiment is to test the cross section and polarisation transfer predictions of perturbative QCD versus that of predictions from Generalised Parton Distribution models. This thesis will give an overview of the pertinent theory, experimental setup in Hall A and the extracting of the π^{0}-photoproduction cross section.
MINERvA - neutrino nucleus cross section experiment
CERN. Geneva
2014-01-01
Recent results from MINERvA, a neutrino cross section experiment at Fermilab, are presented. MINERVA has the goal of providing precision results which will have important impact on oscillation experiments. Initial data runs for muon neutrino and antineutrino beams of ~3.5 GeV have produced a large number of new results. This seminar will introduce the experiment and describe results for quasielastic, pion production, and inclusive cross sections.
Measurement of the pion form factor
International Nuclear Information System (INIS)
Dally, E.; Hauptman, J.; May, C.
1977-01-01
The pion form factor has been measured in the momentum transfer range of 0.03( 2 by scattering pions from atomic electrons in a liquid hydrogen target. The pion form factor is defined to be the elastic scattering cross section divided by that predicted for a point pion. The experiment has been performed in a 100 GeV/c negative pion beam incident on a 50 cm liquid hydrogen target at Fermi laboratory. The corrected form factor equals 0.33+-0.06 f 2 . Vector dominance predicts 0.40 f 2
Differential Cross-Sections for pi- p --> gamma n in the First Resonance Region
Guex-Le Lan, Huong; Hilscher, H; Joseph, C L; Schmitt, H; Tran, M T; Truöl, P; Vaucher, B; Winkelmann, E; Zupancic, Crtomir; Joseph, C L no 1; Tran, M T no 1; Vaucher, B no 1; Winkelmann, E no 1; Bayer, W no 2; Hilscher, H no 2; Schmitt, H no 2; Zupancic, C no 2; Truöl, P no 3; Guex, L H no 1
1975-01-01
Differential cross-sections for negative pion radiative capture on protons at c.m. angles of 60°, 90°, and 120° have been measured at nine incident laboratory energies between 110 and 270 MeV. Comparison with measured cross-sections for pion photoproduction and with conventional multipole analyses shows neither evidence for a violation of time reversal invariance nor for an isotensor component of the electromagnetic current of hardrons. Record added 1974-09-01, las
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.
Mechanism of pion absorption in complex nuclei
International Nuclear Information System (INIS)
Doss, K.G.N.; Wharton, W.R.
Basic geometrical arguments are used to analyze the A dependence of the total pion absorption cross section, the effective number of nucleons sharing the pion momentum and energy, and the proton yields from π + - and π - -induced reactions. The results are consistent with the pions penetrating some distance through the nuclear volume and annihilating on a pair of nucleons. 3 figures
International Nuclear Information System (INIS)
Brunhoeber, H.
2001-11-01
The interference terms R LT and R TT that contribute to the cross section of the charged pion electroproduction have been determined in an electron scattering experiment at the accelerator facility ELSA by detecting the outgoing neutron of the nπ + -decay channel by a large acceptance Time-of-Flight spectrometer covering the Δ + (1232) resonance region at the four momentum transfers of 0.638 GeV 2 and 0.8 GeV 2 . (orig.)
Pion production in relativistic heavy ion collisions
International Nuclear Information System (INIS)
Norbury, J.W.
1983-01-01
A Lorentz-invariant differential cross section for pion production in peripheral, relativistic, heavy ion collisions is calculated for the collisions of an 16 O projectile onto a 12 C target. The pions are produced via excitations of a Δ(3,3) resonant state in the projectile with simultaneous excitation of an M1 giant resonance in the target. A second order amplitude describing resonance formation and decay is derived within the context of second order, time-dependent perturbation theory and a corresponding transition rate is evaluated. This is then applied to the problem of pion production and a differential cross section is calculated using a simple product-of-states model. The whole theory is then re-formulated within a second quantized particle-hole model which describes the basic process of M1 giant resonance formation as well as the formation and decay of the intermediate Δ(3,3) resonance. Subsequently, a new Lorentz-invariant differential cross section is calculated from the particle-hole amplitude. The theoretical cross section is compared with some experimental data and the agreement is found to be satisfactory given the nature of the data and the assumptions of the theory
Hard exclusive pion electroproduction at backward angles with CLAS
Park, K.; Guidal, M.; Gothe, R. W.; Pire, B.; Semenov-Tian-Shansky, K.; Laget, J.-M.; Adhikari, K. P.; Adhikari, S.; Akbar, Z.; Avakian, H.; Ball, J.; Balossino, I.; Baltzell, N. A.; Barion, L.; Battaglieri, M.; Bedlinskiy, I.; Biselli, A. S.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Cao, F. T.; Carman, D. S.; Celentano, A.; Charles, G.; Chetry, T.; Ciullo, G.; Clark, L.; Cole, P. L.; Contalbrigo, M.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Defurne, M.; Deur, A.; Djalali, C.; Dupre, R.; Egiyan, H.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Fersch, R.; Filippi, A.; Garçon, M.; Ghandilyan, Y.; Gilfoyle, G. P.; Girod, F. X.; Golovatch, E.; Griffioen, K. A.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Hattawy, M.; Heddle, D.; Hicks, K.; Holtrop, M.; Hyde, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jenkins, D.; Johnston, S.; Joo, K.; Kabir, M. L.; Keller, D.; Khachatryan, G.; Khachatryan, M.; Khandaker, M.; Kim, W.; Klein, F. J.; Kubarovsky, V.; Kuhn, S. E.; Lanza, L.; Livingston, K.; MacGregor, I. J. D.; Markov, N.; McKinnon, B.; Mirazita, M.; Mokeev, V.; Montgomery, R. A.; Munoz Camacho, C.; Nadel-Turonski, P.; Niccolai, S.; Niculescu, G.; Osipenko, M.; Paolone, M.; Paremuzyan, R.; Pasyuk, E.; Phelps, W.; Pogorelko, O.; Poudel, J.; Price, J. W.; Prok, Y.; Protopopescu, D.; Ripani, M.; Rizzo, A.; Rossi, P.; Sabatié, F.; Salgado, C.; Schumacher, R. A.; Sharabian, Y.; Skorodumina, Iu.; Smith, G. D.; Sokhan, D.; Sparveris, N.; Stepanyan, S.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Tan, J. A.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Wei, X.; Zachariou, N.; Zhang, J.
2018-05-01
We report on the first measurement of cross sections for exclusive deeply virtual pion electroproduction off the proton, ep →e‧ nπ+, above the resonance region at backward pion center-of-mass angles. The φπ* -dependent cross sections were measured, from which we extracted three combinations of structure functions of the proton. Our results are compatible with calculations based on nucleon-to-pion transition distribution amplitudes (TDAs). These non-perturbative objects are defined as matrix elements of three-quark-light-cone-operators and characterize partonic correlations with a particular emphasis on baryon charge distribution inside a nucleon.
Can we get deeper inside the pion at the LHC?
Energy Technology Data Exchange (ETDEWEB)
Petrov, V.A.; Ryutin, R.A.; Sobol, A.E. [Institute for High Energy Physics, Protvino (Russian Federation); Murray, M.J. [University of Kansas, Kansas City, KS (United States)
2012-02-15
We propose a measurement of leading neutrons spectra at LHC in order to extract inclusive {pi}{sup +} p and {pi}{sup +}{pi} {sup +} cross-sections with high p{sub T} jets production. The cross-sections for these processes are simulated with the use of parton distributions in hadrons. In this work we estimate the possibility to extract parton distributions in the pion from the data on these cross-sections and also search for signatures of fundamental differences in the pion and proton structure. (orig.)
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)
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
LAMBDA p total cross-section measurement
CERN PhotoLab
1970-01-01
A view of the apparatus used for the LAMBDA p total cross-section measurement at the time of its installation. The hyperons decaying into a proton and a pion in the conical tank in front were detected in the magnet spectrometer in the upper half of the picture. A novel detection technique using exclusively multiwire proportional chambers was employed.
Invariant potential for elastic pion--nucleus scattering
International Nuclear Information System (INIS)
Cammarata, J.B.; Banerjee, M.K.
1976-01-01
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 frame, 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
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.
Real and virtual pions in nuclei
International Nuclear Information System (INIS)
Giraud, N.
1984-02-01
The thesis first part is concerned with physical pion interaction with deuton, studied in a three-body problem frame. The elastic cross-section in the energy range near the resonance (3-3), has been deduced taking in account the pion virtual absorption. The second part is concerned with virtual pion in nuclei. In particular the virtual pion cloud around the nucleus has been studied and the effective constant coupling pion-nucleus has been deduced. This one is strongly reduced by polorazation effects of the nuclear medium (essentially by virtual excitation of the Δ isobar), in relation to its value for free nucleon collection. In the frame of the same polarization model, the pion field inside the nucleus has been studied also. This field is lowered for small momentum transfer. It is increased for large momentum transfer. This last phenomenon corresponds to critical opalescence related to phase transition of pion condensation [fr
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.
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
Inelastic pion scattering from 3H and 3He
International Nuclear Information System (INIS)
Berman, B.L.; Anderson, G.C.; Briscoe, W.J.; Mokhtari, A.; Petrov, A.M.; Sadler, M.E.; Barlow, D.B.; Nefkens, B.M.K.; Pillai, C.
1995-01-01
Cross sections have been measured for the inelastic scattering of π + and π - mesons from 3 H and 3 He in the 10-MeV interval just above the breakup thresholds, for incident pion energies of 142, 180, and 220 MeV and scattering angles of 40 degree, 60 degree, 80 degree, 90 degree, and 110 degree. No significant departure from unity is observed for the ratios of charge-symmetric cross sections. Comparisons are made with elastic pion-scattering and inelastic electron-scattering data
Measurement of np→dπ0 cross sections very near threshold
International Nuclear Information System (INIS)
Hutcheon, D.A.; Abegg, R.; Greeniaus, L.G.; Miller, C.A.; Korkmaz, E.; Moss, G.A.; Edwards, G.W.R.; Mack, D.; Olsen, W.C.; Ye, Y.
1989-06-01
We have measured np→dπ 0 cross sections at ten beam energies within 16 MeV of threshold. Total cross sections followed closely the relationship σ tot (np→dπ 0 ) = (1/2)[(184±5)η 3 ]μb, where η is the c.m. pion momentum in units of m π c. The differential cross sections are anisotropic at only 1 MeV (c.m.) above threshold. These results are predicted by Faddeev model calculations and by a perturbative model. Our cross sections are in fair agreement with previous π + d→pp data. (Author) 12 refs., tab., 4 figs
[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
Neutrino-nucleus cross sections for oscillation experiments
Katori, Teppei; Martini, Marco
2018-01-01
Neutrino oscillations physics is entering an era of high precision. In this context, accelerator-based neutrino experiments need a reduction in systematic errors to the level of a few percent. Today, one of the most important sources of systematic errors are neutrino-nucleus cross sections which, in the energy region of hundreds of MeV to a few GeV, are known to a precision not exceeding 20%. In this article we review the present experimental and theoretical knowledge of neutrino-nucleus interaction physics. After introducing neutrino-oscillation physics and accelerator-based neutrino experiments, we give an overview of general aspects of neutrino-nucleus cross sections, from both the theoretical and experimental point of view. Then, we focus on these cross sections in different reaction channels. We start with the quasi-elastic and quasi-elastic-like cross section, placing a special emphasis on the multinucleon emission channel, which has attracted a lot of attention in the last few years. We review the main aspects of the different microscopic models for this channel by discussing analogies and the differences among them. The discussion is always driven by a comparison with the experimental data. We then consider the one-pion production channel where agreement between data and theory remains highly unsatisfactory. We describe how to interpret pion data, and then analyze, in particular, the puzzle related to the difficulty of theoretical models and Monte Carlo to simultaneously describe MiniBooNE and MINERvA experimental results. Inclusive cross sections are also discussed, as well as the comparison between the {ν }μ and {ν }e cross sections, relevant for the charge-conjugation-parity violation experiments. The impact of nuclear effects on the reconstruction of neutrino energy and on the determination of the neutrino-oscillation parameters is also reviewed. Finally, we look to the future by discussing projects and efforts in relation to future detectors, beams
Evaluation of the D(γ,n) reaction cross section
International Nuclear Information System (INIS)
Murata, T.
1994-01-01
Evaluation was performed for the cross section of photo-disintegration of Deuteron in the photon energy range between the threshold energy of the reaction (2.224 MeV) and pion production threshold (140 MeV). Angular distributions of the emitted neutrons were also evaluated. (author)
Spin-Dependent Cross Sections in Pion Produc- tion
Pintex Collaboration; von Przewoski, B.; Dzemidzic, M.; Doskow, J.; Meyer, H. O.; Pollock, R. E.; Rinckel, T.; Sperisen, F.; Wolanski, M.; Haeberli, W.; Lorentz, B.; Quin, P.; Rathmann, F.; Schwartz, B.; Wise, T.; Daehnick, W.; Flammang, R.; Tedeschi, D.; Pancella, P. V.
1997-04-01
An experiment to measure ΔσL and ΔσT for pion production in pp scattering is in preparation at the Indiana Cooler. Both, pparrowppπ^circ and pparrowpnπ^+ reactions, will be studied. Either two charged particles or the neutron and the proton are detected in the exit channel. The experiment requires the acceleration of longitudinally polarized stored protons. Recently, longitudinally polarized beam has been successfully stored and accelerated to 400 MeV. The experiment uses the Wisconsin/IUCF polarized storage cell target. Upgrades to the experimental setup which has been used previously for a measurement of spin correlation parameters in pp elastic scattering will be discussed. The detector response is studied by means of a Monte Carlo simulation. Expected performance parameters will be presented.
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.
Cross sections for hadron and lepton production processes
International Nuclear Information System (INIS)
Bhattacharya, R.
1976-01-01
Charged heavy lepton production in proton-proton collisions is studied. Motivated by recent experimental results from the Stanford Linear Accelerator Center a parton model analysis is given of the reaction p + p → L + + L - + x → μ +- + e/ -+ / + neutrinos + x. Results are presented for the total cross section and the differential cross sections with respect to the invariant mass squared of the final charged leptons and the transverse momenta of each one of them. The two-photon mechanism for pair production in colliding beam exeriments is considered. Through the use of mapped invariant integration variables, a reliable exact numerical calculation of the cross section for the production of muon and pion pairs by the two-photon mechanism is provided. Results are given for the exact total cross sections and also the differential cross sections with respect to the invariant mass squared of the pair. These are compared to the results obtained from the equivalent photon approximation method
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)
Detecting the neutral top-pion at e+e- colliders
International Nuclear Information System (INIS)
Wang Xuelei; Yang Yueling; Li Bingzhong
2004-01-01
We investigate some processes of the associated production of a neutral top-pion Π t 0 with a pair of fermions (e + e - →ff-barΠ t 0 ) in the context of top-color-assisted technicolor (TC2) theory in the future e + e - colliders. The studies show that the largest cross sections of the processes e + e - →f ' f ' Π t 0 (f ' =u,d,c,s,μ,τ) could only reach the level of 0.01 fb; we can hardly detect a neutral top-pion through these processes. For the processes e + e - →e + e - Π t 0 , e + e - →tt-barΠ t 0 , and e + e - →bb-barΠ t 0 , the cross sections of these processes are at the level of a few fb for the favorable parameters, and a few tens, even hundreds, of neutral top-pion events can be produced at future e + e - colliders each year through these processes. With the clean background of the flavor-changing tc-bar channel, the top-pion events can possibly be detected at the planned high luminosity e + e - colliders. Therefore, such neutral top-pion production processes provide a useful way to detect a neutral top-pion and test the TC2 model directly
Nuclear transparency and effective kaon-nucleon cross section from the A(e,e'K+) reaction
International Nuclear Information System (INIS)
Nuruzzaman; Dutta, D.; Arrington, J.; Fassi, L. El; Zheng, X. C.; Asaturyan, R.; Mkrtchyan, H.; Navasardyan, T.; Tadevosyan, V.; Benmokhtar, F.; Boeglin, W.; Markowitz, P.; Bosted, P.; Bruell, A.; Chudakov, E.; Ent, R.; Fenker, H. C.; Gaskell, D.; Jones, M. K.; Lung, A. F.
2011-01-01
We have determined the transparency of the nuclear medium to kaons from A(e,e ' K + ) measurements on 12 C, 63 Cu, and 197 Au targets. The measurements were performed at the Jefferson Laboratory and span a range in four-momentum-transfer squared Q 2 =1.1-3.0 GeV 2 . The nuclear transparency was defined as the ratio of measured kaon electroproduction cross sections with respect to deuterium (σ A /σ D ). We further extracted the atomic number (A) dependence of the transparency as parametrized by T=(A/2) α-1 and, within a simple model assumption, the in-medium effective kaon-nucleon cross sections. The effective cross sections extracted from the electroproduction data were found to be smaller than the free cross sections determined from kaon-nucleon scattering experiments, and the parameter α was found to be significantly larger than those obtained from kaon-nucleus scattering. We have included similar comparisons between pion- and proton-nucleon effective cross sections as determined from electron-scattering experiments and pion-nucleus and proton-nucleus scattering data.
Absolute differential cross sections for π±p elastic scattering at 30 ≤ Tπ ≤ 67 MeV
International Nuclear Information System (INIS)
Brack, J.T.; Ristinen, R.A.; Kraushaar, J.J.
1989-11-01
Absolute π±p differential cross sections have been measured at incident pion energies of 30.0, 45.0, and 66.8 MeV, using active targets of scintillator plastic (CH 1.1 ) to detect recoil protons in coincidence with scattered pions. Statistical uncertainties are typically ±3%; systematic uncertainties are ±2%. The results are consistent with two earlier measurements by this group employing different experimental techniques at 67 MeV and higher incident pion energies. The π - p cross sections are in good agreement with currently accepted phase-shift analyses, but the corresponding π + p predictions are typically 15% higher at large angles than the π + p data reported here
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.
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
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...
Charged pion production from neutron--proton collisions at 790 MeV
International Nuclear Information System (INIS)
Thomas, W.R.
1977-09-01
The two reactions np → nnπ + and np → ppπ - were studied at 790 MeV (incident neutron energy). Pion spectra were measured at 10 different angles with a multiwire proportional chamber spectrometer. Approximately 100,000 events were analyzed. The angular distribution of pions in the np center of momentum system (d sigma/dΩ*) was given by [(123.1 +- 2.7) + (88.3 +- 4.9)cos 2 (theta*)](μb/sr). The cross section sigma(np → NNπ/sup +-/) was determined to be 1.92 +- .20 mb by integrating (d sigma/dΩ*) over all angles. The partial cross section for pion production from T = 0 np interactions (sigma 01 ) was found to be .1/sub -.1//sup +.5/ mb by using the relation sigma 01 = 2sigma(np → NNπ/sup +-)--sigma(pp → ppπ 0 ). Stronger indications of nonresonant pion production were given by the presence of asymmetries between the positive and negative pion spectra and a comparison of the data with an isobar model calculation
Pion production experiments at IUCF
Daehnick, W. W.
2001-12-01
Pion production in pp collisions is of special interest near threshold where very few partial waves contribute and where calculations should be manageable and results more conclusive. The first explicit calculations for pp → ppπ0 and pp → pnπ+ cross sections near threshold were made by Koltun and Reitan in 1966 and by Schillaci, Silbar and Young in 1969. They remained unchallenged and untested until cross sections very close to threshold could finally be measured1,2. The realization that the pioneering calculations missed the true cross sections by a wide margin has spurred much new theoretical research.3,4,5 ...
Anisotropy of the pion emission in relativistic nucleus-nucleus collisions
International Nuclear Information System (INIS)
Babinet, R.; Cavata, C.; Demoulins, M.; Fanet, H.; Gosset, J.; Lemaire, M.C.; Le Merdy, A.; L'Hote, D.; Lucas, B.; Poitou, J.; Alard, J.P.; Augerat, J.; Bastid, N.; Charmensat, P.; Dupieux, P.; Fraysse, L.; Marroncle, J.; Montarou, G.; Parizet, M.J.; Ramani, A.; Brochard, F.; Gorodetzky, P.; Racca, C.
1990-01-01
The production of pions and baryons from Ne and Ar induced reactions on Ca, NaF, Nb and Pb targets, in the range of .2 to 1 GeV per nucleon, is discussed. The 4π detector Diogenes at the Saturne accelerator facility is applied. The reaction plane is determined from the baryon momenta distribution and used as a reference for the pion triple differential cross-sections. A transverse momentum analysis is carried out for baryons and pions. The pion squared reduced impact parameter and the flow characteristics are given. The results show that the azimuthal anisotropy of pion emission increases with the asymmetry of the system. The evidence that pion absorption effects may be responsible for the azimuthal anisotropy of the pion emission is provided
Multiproton final states in positive pion absorption below the Δ(1232) resonance
International Nuclear Information System (INIS)
Giannelli, R. A.; Ritchie, B. G.; Applegate, J. M.; Beck, E.; Beck, J.; Vanderpool, A. O.; Morris, C. L.; Rahwool-Sullivan, M.; Jones, M. K.; Ransome, R. D.
2000-01-01
Inclusive cross sections for positive pion absorption leading to final states including two or more protons have been measured with a large solid angle detector for incident pion energies from 30 to 135 MeV for targets with A=2-208. The mass dependences for the inclusive (π + ,2p), (π + ,3p), and total absorption cross sections for multiproton final states were found to be proportional to A n with n≅0.5. These cross sections also were observed to have an energy dependence at energies below 150 MeV reflective of the importance of the Δ(1232) resonance, similar to that observed for πd→pp. The inclusive cross sections for (π + ,4p) were found to be less than 10 mb for all targets at all energies. Estimates were also obtained for cross sections for pion absorption leading to 2p1n and 3p1n final states. Quasideuteron absorption contributions increase slowly with A, and the energy dependence of those contributions mirrors that for πd→pp. The data obtained here for multiproton final states indicate that a significant fraction of absorption events, increasing with A, most likely arises from final states containing fewer than two protons. (c) 2000 The American Physical Society
Rosenbluth Separation of the π^{0} Electroproduction Cross Section.
Defurne, M; Mazouz, M; Ahmed, Z; Albataineh, H; Allada, K; Aniol, K A; Bellini, V; Benali, M; Boeglin, W; Bertin, P; Brossard, M; Camsonne, A; Canan, M; Chandavar, S; Chen, C; Chen, J-P; de Jager, C W; de Leo, R; Desnault, C; Deur, A; El Fassi, L; Ent, R; Flay, D; Friend, M; Fuchey, E; Frullani, S; Garibaldi, F; Gaskell, D; Giusa, A; Glamazdin, O; Golge, S; Gomez, J; Hansen, O; Higinbotham, D; Holmstrom, T; Horn, T; Huang, J; Huang, M; Huber, G M; Hyde, C E; Iqbal, S; Itard, F; Kang, Ho; Kang, Hy; Kelleher, A; Keppel, C; Koirala, S; Korover, I; LeRose, J J; Lindgren, R; Long, E; Magne, M; Mammei, J; Margaziotis, D J; Markowitz, P; Martí Jiménez-Argüello, A; Meddi, F; Meekins, D; Michaels, R; Mihovilovic, M; Muangma, N; Muñoz Camacho, C; Nadel-Turonski, P; Nuruzzaman, N; Paremuzyan, R; Puckett, A; Punjabi, V; Qiang, Y; Rakhman, A; Rashad, M N H; Riordan, S; Roche, J; Russo, G; Sabatié, F; Saenboonruang, K; Saha, A; Sawatzky, B; Selvy, L; Shahinyan, A; Sirca, S; Solvignon, P; Sperduto, M L; Subedi, R; Sulkosky, V; Sutera, C; Tobias, W A; Urciuoli, G M; Wang, D; Wojtsekhowski, B; Yao, H; Ye, Z; Zana, L; Zhan, X; Zhang, J; Zhao, B; Zhao, Z; Zheng, X; Zhu, P
2016-12-23
We present deeply virtual π^{0} electroproduction cross-section measurements at x_{B}=0.36 and three different Q^{2} values ranging from 1.5 to 2 GeV^{2}, obtained from Jefferson Lab Hall A experiment E07-007. The Rosenbluth technique is used to separate the longitudinal and transverse responses. Results demonstrate that the cross section is dominated by its transverse component and, thus, is far from the asymptotic limit predicted by perturbative quantum chromodynamics. Nonetheless, an indication of a nonzero longitudinal contribution is provided by the measured interference term σ_{LT}. Results are compared with several models based on the leading-twist approach of generalized parton distributions (GPDs). In particular, a fair agreement is obtained with models in which the scattering amplitude includes convolution terms of chiral-odd (transversity) GPDs of the nucleon with the twist-3 pion distribution amplitude. This experiment, together with previous extensive unseparated measurements, provides strong support to the exciting idea that transversity GPDs can be accessed via neutral pion electroproduction in the high-Q^{2} regime.
Rosenbluth Separation of the π0 Electroproduction Cross Section
Defurne, M.; Mazouz, M.; Ahmed, Z.; Albataineh, H.; Allada, K.; Aniol, K. A.; Bellini, V.; Benali, M.; Boeglin, W.; Bertin, P.; Brossard, M.; Camsonne, A.; Canan, M.; Chandavar, S.; Chen, C.; Chen, J.-P.; de Jager, C. W.; de Leo, R.; Desnault, C.; Deur, A.; El Fassi, L.; Ent, R.; Flay, D.; Friend, M.; Fuchey, E.; Frullani, S.; Garibaldi, F.; Gaskell, D.; Giusa, A.; Glamazdin, O.; Golge, S.; Gomez, J.; Hansen, O.; Higinbotham, D.; Holmstrom, T.; Horn, T.; Huang, J.; Huang, M.; Huber, G. M.; Hyde, C. E.; Iqbal, S.; Itard, F.; Kang, Ho.; Kang, Hy.; Kelleher, A.; Keppel, C.; Koirala, S.; Korover, I.; LeRose, J. J.; Lindgren, R.; Long, E.; Magne, M.; Mammei, J.; Margaziotis, D. J.; Markowitz, P.; Martí Jiménez-Argüello, A.; Meddi, F.; Meekins, D.; Michaels, R.; Mihovilovic, M.; Muangma, N.; Muñoz Camacho, C.; Nadel-Turonski, P.; Nuruzzaman, N.; Paremuzyan, R.; Puckett, A.; Punjabi, V.; Qiang, Y.; Rakhman, A.; Rashad, M. N. H.; Riordan, S.; Roche, J.; Russo, G.; Sabatié, F.; Saenboonruang, K.; Saha, A.; Sawatzky, B.; Selvy, L.; Shahinyan, A.; Sirca, S.; Solvignon, P.; Sperduto, M. L.; Subedi, R.; Sulkosky, V.; Sutera, C.; Tobias, W. A.; Urciuoli, G. M.; Wang, D.; Wojtsekhowski, B.; Yao, H.; Ye, Z.; Zana, L.; Zhan, X.; Zhang, J.; Zhao, B.; Zhao, Z.; Zheng, X.; Zhu, P.; Jefferson Lab Hall A Collaboration
2016-12-01
We present deeply virtual π0 electroproduction cross-section measurements at xB=0.36 and three different Q2 values ranging from 1.5 to 2 GeV 2 , obtained from Jefferson Lab Hall A experiment E07-007. The Rosenbluth technique is used to separate the longitudinal and transverse responses. Results demonstrate that the cross section is dominated by its transverse component and, thus, is far from the asymptotic limit predicted by perturbative quantum chromodynamics. Nonetheless, an indication of a nonzero longitudinal contribution is provided by the measured interference term σL T. Results are compared with several models based on the leading-twist approach of generalized parton distributions (GPDs). In particular, a fair agreement is obtained with models in which the scattering amplitude includes convolution terms of chiral-odd (transversity) GPDs of the nucleon with the twist-3 pion distribution amplitude. This experiment, together with previous extensive unseparated measurements, provides strong support to the exciting idea that transversity GPDs can be accessed via neutral pion electroproduction in the high-Q2 regime.
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)
Search for structure in the low-energy anti p-p annihilation cross section
International Nuclear Information System (INIS)
Jastrzembski, E.; Haik, N.; McFarlane, W.K.; Mandelkern, M.A.; Schultz, D.C.; Amsler, C.; Hermann, C.C.; Wolfe, D.M.
1980-01-01
The relative cross section for annihilation of antiprotons on hydrogen into one or more charged pions was measured. Incident beam momentum was 600 MeV/c. Numbers of observed events (relative) were compared with those expected from the sensitivity of the apparatus. A phase-space model was used for p-barp annihilation. Relative cross sections are plotted vs invariant mass. Upper limits on cross sections for the formation of narrow resonances in the S region are given; previously reported structures are not confirmed. 2 figures, 1 table
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
Neutrino production of single pions: Dipole description
International Nuclear Information System (INIS)
Kopeliovich, B. Z.; Schmidt, Ivan; Siddikov, M.
2011-01-01
The light-cone distribution amplitudes for the axial current are derived within the instanton vacuum model, which incorporates nonperturbative effects including spontaneous chiral symmetry breaking. This allows one to extend applicability of the dipole approach, usually used in the perturbative domain, down to Q 2 →0, where the partially conserved axial current imposes a relation between the neutrino-production cross section and the one induced by pions. A dramatic breakdown of the Adler relation for diffractive neutrino production of pions, caused by absorptive corrections, was revealed recently by Kopeliovich et al.. Indeed, comparing with the cross section predicted by the dipole phenomenology at Q 2 →0 on a proton target we confirmed the sizable deviation from the value given by the Adler relation, as was estimated by Kopeliovich et al. within a simplified two-channel model. The dipole approach also confirms that in the black-disk limit, where the absorptive corrections maximize, the diffractive cross section ceases, on the contrary to the expectation based on the partially conserved axial current.
Palczewski, Tomasz Jan
2009-01-01
One of physics goals of the NA61/SHINE experiment is a measurement of hadron production cross sections from proton-Carbon interactions at 31GeV/c for the T2K experiment at J-PARC. A precise knowledge of differential cross sections for pion and kaon production is of importance for improving the accuracy of neutrino flux simulations. The NA61 detector has a large angular acceptance, full coverage of the T2K phase space region, and good particle identification. In this work the analyses of negatively charged pion production are presented. Two different methods of negative pion selection and corrections for detector effects are discussed. Finally, preliminary dn/dp distributions of negatively charged pion in p+C interactions at 31 GeV/c are presented.
Neudachin, V G; Yudin, N P
2002-01-01
Investigation of the dominant role of the simplest t-pole diagrams is completed in the processes of pion electroproduction on nucleons at quasielastic knock out kinematics and electron energies of a few GeV. Competition role of pi- and rho-meson t-pole diagrams and s-pole diagram (tree diagram) is regarded. When virtual photon mass is large enough (Q sup 2 >= 2 (GeV/c) sup 2), the latter amplitude is not essential both for longitudinal (d sigma sub L /dt) and for transverse (d sigma sub T /dt) cross sections. At Q sup 2 = 0.7 (GeV/c) sup 2 in the longitudinal cross section the interference term between pion t-pole and s-pole amplitudes is still essential. Vertex functions g subrho sub N sub N (t), obtained from the cross sections of the quasielastic knockout of rho mesons and from cross section of pion photoproduction, are compared. Their discrepancy must give impulse to the development of gauge invariant theory of pion photoproduction
Results in pion proton scattering near the higher resonances (1961)
International Nuclear Information System (INIS)
Falk-Vairant, P.; Valladas, G.
1961-01-01
We present briefly the available Information on the total cross sections for pion proton scattering in the energy region from 400 MeV to 1.5 GeV. We also have collected all results on total cross sections for particular channels like elastic scattering, inelastic scattering and charge exchange. Using new results on the total cross section for neutral events, we have plotted separately the cross section for elastic and for inelastic scattering in the T = 1/2 state. (authors) [fr
Energy Technology Data Exchange (ETDEWEB)
Scanavini, Scanavini,Giacomo [Yale U.
2017-01-01
This thesis presents a work done in the context of the Fermilab Neutrino Intensity Frontier. In this analysis, the cross section of single charged pion production in charged-current neutrino and antineutrino interactions with the argon nucleus target are measured. These measurements are performed using the Argon Neutrino Test (ArgoNeuT) detector exposed to the Fermilab Neutrino From The Main Injector (NuMI) beam operating in the low energy antineutrino mode. The signal is a charged-current μ interaction in the detector, with exactly one charged pion exiting the target nucleus, with momentum above 100 MeV/c. There shouldn’t be any 0 or kaons in the final state. There is no restriction on other mesons or nucleons. Total and differential cross section measurements are presented. The results are reported in terms of outgoing muon angle and momentum, outgoing pion angle and angle between outgoing pion and muon. The total cross sections, averaged over the flux, are found to be 8.2 ± 0.9 (stat) +0.9 -1.1 (syst) × 10-38 cm2 per argon nuclei and 2.5 ± 0.4 (stat) ± 0.5 (syst) × 10-37 cm2 per argon nuclei for antineutrino and neutrino respectively at a mean neutrino energy of 3.6 GeV (antineutrinos) and 9.6 GeV (neutrinos). This is the first time the single pion production in charged-current interactions cross section is measured on argon nuclei.
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
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
Low energy pion detection by a silicon surface barrier telescope
International Nuclear Information System (INIS)
Sealock, R.M.; Caplan, H.S.; Leung, M.K.
1978-01-01
Four telescopes of three (2-ΔE, 1-E) silicon surface barrier detectors each, mounted in the focal plane of a magnetic spectrometer, have been used to detect positive pions in the energy range from 4.7-17.9 MeV and negative pions from 14.1-17.9 MeV. Positive pions from 4.7-12.7 MeV were stopped in the third detector while positive and negative pions from 14.1-17.9 MeV were detected in transmission. For energies greater than 7.4 MeV aluminum moderators were placed in front of the first detector to degrade the pion energy. Energy spectra show well resolved pion peaks with extremely low background. Double differential cross sections for the 12 C(e,π + ) 12 B,e' reaction have been measured. (Auth.)
Mislivec, A.; Higuera, A.; Aliaga, L.; Bellantoni, L.; Bercellie, A.; Betancourt, M.; Bodek, A.; Bravar, A.; Budd, H.; Caceres v., G. F. R.; Cai, T.; Martinez Caicedo, D. A.; Carneiro, M. F.; Chavarria, E.; da Motta, H.; Dytman, S. A.; Díaz, G. A.; Felix, J.; Fields, L.; Fine, R.; Gago, A. M.; Galindo, R.; Gallagher, H.; Ghosh, A.; Gran, R.; Harris, D. A.; Hurtado, K.; Jena, D.; Kleykamp, J.; Kordosky, M.; Le, T.; Maher, E.; Manly, S.; Mann, W. A.; Marshall, C. M.; McFarland, K. S.; Messerly, B.; Miller, J.; Morfín, J. G.; Mousseau, J.; Naples, D.; Nelson, J. K.; Nguyen, C.; Norrick, A.; Nuruzzaman, Paolone, V.; Perdue, G. N.; Ramírez, M. A.; Ransome, R. D.; Ray, H.; Ren, L.; Rimal, D.; Rodrigues, P. A.; Ruterbories, D.; Schellman, H.; Solano Salinas, C. J.; Sultana, M.; Sánchez Falero, S.; Tagg, N.; Valencia, E.; Wospakrik, M.; Yaeggy, B.; Zavala, G.; MinerνA Collaboration
2018-02-01
Neutrino induced coherent charged pion production on nuclei, ν¯ μA →μ±π∓A , is a rare inelastic interaction in which the four-momentum squared transferred to the nucleus is nearly zero, leaving it intact. We identify such events in the scintillator of MINERvA by reconstructing |t | from the final state pion and muon momenta and by removing events with evidence of energetic nuclear recoil or production of other final state particles. We measure the total neutrino and antineutrino cross sections as a function of neutrino energy between 2 and 20 GeV and measure flux integrated differential cross sections as a function of Q2 , Eπ, and θπ . The Q2 dependence and equality of the neutrino and antineutrino cross sections at finite Q2 provide a confirmation of Adler's partial conservation of axial current hypothesis.
Investigation of Compton effect on π-meson and charged pion polarizability
International Nuclear Information System (INIS)
Antipov, Yu.M.; Batarin, V.A.; Bezzubov, V.A.
1986-01-01
The results of an experiment aimed at the study of the 40 GeV/c pion radiative scattering on nuclei at small momentum transfers are presented. Compton effect on the pion was investigated and the charged pion polarizability was measured. The pion Compton-effect cross section dependence on the incident photon energy ω' 1 (rest pion frame) was measured in the 100 - 600 MeV range. The polarizability of charged pion from the analysis of Compton-effect events has been found to be β π =-α π =(-6.9 ± 1.4 stat. ± 1.2 syst. )x10 -43 cm 3 and the sun of pion electrical α π and magnetic β π polarizability has been estimated to be in agreement with theoretical predictions: α π +β π ≅ 0
Measurement of Dijet Cross Sections in ep Interactions with a Leading Neutron at HERA
Aktas, A.; Anthonis, T.; Aplin, S.; Asmone, A.; Babaev, A.; Backovic, S.; Bahr, J.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, Ch.; Berger, N.; Bizot, J.C.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brandt, G.; Brisson, V.; Brown, D.P.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Caron, S.; Cassol-Brunner, F.; Cerny, K.; Chekelian, V.; Contreras, J.G.; Coughlan, J.A.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; Delcourt, B.; Demirchyan, R.; De Roeck, A.; Desch, K.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, Guenter; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Ellerbrock, M.; Elsen, E.; Erdmann, W.; Essenov, S.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Finke, L.; Fleischer, M.; Fleischmann, P.; Fleming, Y.H.; Flucke, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Franke, G.; Frising, G.; Frisson, T.; Gabathuler, E.; Garutti, E.; Gayler, J.; Gerhards, R.; Gerlich, C.; Ghazaryan, Samvel; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Goyon, C.; Grab, C.; Greenshaw, T.; Gregori, M.; Grindhammer, Guenter; Gwilliam, C.; Haidt, D.; Hajduk, L.; Haller, J.; Hansson, M.; Heinzelmann, G.; Henderson, R.C.W.; Henschel, H.; Henshaw, O.; Herrera, G.; Herynek, I.; Heuer, R.-D.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, H.; Kapichine, M.; Karlsson, M.; Katzy, J.; Keller, N.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Korbel, V.; Kostka, P.; Koutouev, R.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Kuckens, J.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Laycock, P.; Lebedev, A.; Leiner, B.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; List, B.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lueders, H.; Luke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marshall, R.; Martisikova, M.; Martyn, H.-U.; Maxeld, S.J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, Matthias Ulrich; Muller, K.; Murin, P.; Nankov, K.; Naroska, B.; Naumann, J.; Naumann, Th.; Newman, Paul R.; Niebuhr, C.; Nikiforov, A.; Nikitin, D.; Nowak, G.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J.E.; Osman, S.; Ozerov, D.; Pascaud, C.; Patel, G.D.; Peez, M.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Poschl, R.; Portheault, B.; Povh, B.; Prideaux, P.; Raicevic, N.; Reimer, P.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salvaire, F.; Sankey, D.P.C.; Sauvan, E.; Schatzel, S.; Scheins, J.; Schilling, F.-P.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schoning, A.; Schroder, V.; Schultz-Coulon, H.-C.; Schwanenberger, C.; Sedlak, K.; Sefkow, F.; Sheviakov, I.; Shtarkov, L.N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Tchoulakov, V.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsakov, I.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, Marcel; Usik, A.; Utkin, D.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Van Remortel, N.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vest, A.; Vinokurova, S.; Volchinski, V.; Vujicic, B.; Wacker, K.; Wagner, J.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Werner, N.; Wessels, M.; Wessling, B.; Wigmore, C.; Winter, G.-G.; Wissing, Ch.; Wolf, R.; Wunsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zimmermann, J.; Zohrabyan, H.; Zomer, F.
2005-01-01
Measurements are reported of the production of dijet events with a leading neutron in ep interactions at HERA. Differential cross sections for photoproduction and deep inelastic scattering are presented as a function of several kinematic variables. Leading order QCD simulation programs are compared with the measurements. Models in which the real or virtual photon interacts with a parton of an exchanged pion are able to describe the data. Next-to-leading order perturbative QCD calculations based on pion exchange are found to be in good agreement with the measured cross sections. The fraction of leading neutron dijet events with respect to all dijet events is also determined. The dijet events with a leading neutron have a lower fraction of resolved photon processes than do the inclusive dijet data.
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, 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).
Energy Technology Data Exchange (ETDEWEB)
Dicello, J.F. (Clarkson Univ., Potsdam, NY (USA)); Schillaci, M.E.; Liu Lonchang (Los Alamos National Lab., NM (USA))
1990-01-01
When high-energy cosmic rays interact with electronics or other materials in a spacecraft, including the occupants themselves, pions are produced as secondary particles. These secondary pions interact further in the materials producing nuclear secondaries, including nuclear recoils and heavy-ion tertiaries. The secondary pions and the the tertiary particles are capable of producing single-event upsets and other damage in integrated circuits and damage in biological systems. Negative pions stopping in materials are particularly effective because of their unique ability to produce short-range heavy particles from pion stars. With the Los Alamos National Laboratory's version of the intranuclear cascade evaporation code, VEGAS, we have calculated the number of pions produced per energy interval per incident proton from 800 MeV protons on aluminum-27 and silicon-28 along with corresponding results for neutrons, protons, and heavier ions. (orig.).
Charged-current inclusive neutrino cross sections in the SuperScaling model
Energy Technology Data Exchange (ETDEWEB)
Ivanov, M. V., E-mail: martin.inrne@gmail.com [Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, Sofia 1784 (Bulgaria); Grupo de Física Nuclear, Departamento de Física Atómica, Molecular y Nuclear, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, Madrid E-28040 (Spain); Megias, G. D.; Caballero, J. A. [Departamento de Física Atómica, Molecular y Nuclear, Universidad de Sevilla, 41080 Sevilla (Spain); González-Jiménez, R. [Department of Physics and Astronomy, Ghent University, Proeftuinstraat 86, B-9000 Gent (Belgium); Moreno, O.; Donnelly, T. W. [Center for Theoretical Physics, Laboratory for Nuclear Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Barbaro, M. B. [Dipartimento di Fisica, Università di Torino and INFN, Sezione di Torino, Via P. Giuria 1, 10125 Torino (Italy); Antonov, A. N. [Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, Sofia 1784 (Bulgaria); Moya de Guerra, E.; Udías, J. M. [Grupo de Física Nuclear, Departamento de Física Atómica, Molecular y Nuclear, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, Madrid E-28040 (Spain)
2016-03-25
SuperScaling model (SuSA) predictions to neutrino-induced charged-current π{sup +} production in the Δ-resonance region are explored under MiniBooNE experimental conditions. The SuSA charged-current π{sup +} results are in good agreement with data on neutrino flux-averaged double-differential cross sections. The SuSA model for quasielastic scattering and its extension to the pion production region are used for predictions of charged-current inclusive neutrino-nucleus cross sections. Results are also compared with the T2K experimental data for inclusive scattering.
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 -
Multi-nucleon pion absorption in the 4He(π+,ppp)n reaction
International Nuclear Information System (INIS)
Weber, P.; McAlister, J.; Olszewski, R.; Feltham, A.; Hanna, M.; Johnson, R.R.; Pavan, M.; Ponting, C.; Rozon, F.M.; Sevior, M.; Sossi, V.; Vetterli, D.; Humphrey, D.; Lolos, G.J.; Papandreou, Z.; Tacik, R.; Ottewell, D.; Sheffer, G.; Smith, G.R.; Mardor, Y.; May-Tal, S.
1990-08-01
Three-proton emission cross sections for the 4 He(π + ,ppp)n reaction were measured at an incident pion kinetic energy of T pi + =165 MeV over a wide angular range in a kinematically complete experiment. Angular correlations, missing momentum distributions and energy spectra are compared with three- and four-body phase space Monte Carlo calculations. The results provide strong evidence that most of the three-proton coincidences result from three-nucleon absorption. From phase-space integration the total three-nucleon absorption cross section is estimated to be σ 3N =4.8 ± 1.0 mb. The cross section involving four nucleons is small and is estimated to be σ 4N 4 He, multi-nucleon pion absorption seems to represent only a small fraction. (Author) (40 refs., 3 tabs., 15 figs.)
Deeply virtual compton scattering on a virtual pion target
International Nuclear Information System (INIS)
Amrath, D.; Diehl, M.; Lansberg, J.P.; Heidelberg Univ.
2008-07-01
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.)
Gravitational wave from dark sector with dark pion
Energy Technology Data Exchange (ETDEWEB)
Tsumura, Koji [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan); Yamada, Masatoshi [Institut für Theoretische Physik, Universität Heidelberg, Philosophenweg 16, 69120 Heidelberg (Germany); Yamaguchi, Yuya, E-mail: ko2@gauge.scphys.kyoto-u.ac.jp, E-mail: m.yamada@thphys.uni-heidelberg.de, E-mail: yy@particle.sci.hokudai.ac.jp [Department of Physics, Faculty of Science, Hokkaido University, Sapporo 060-0810 (Japan)
2017-07-01
In this work, we investigate the spectra of gravitational waves produced by chiral symmetry breaking in dark quantum chromodynamics (dQCD) sector. The dark pion (π) can be a dark matter candidate as weakly interacting massive particle (WIMP) or strongly interacting massive particle (SIMP). For a WIMP scenario, we introduce the dQCD sector coupled to the standard model (SM) sector with classical scale invariance and investigate the annihilation process of the dark pion via the 2π → 2 SM process. For a SIMP scenario, we investigate the 3π → 2π annihilation process of the dark pion as a SIMP using chiral perturbation theory. We find that in the WIMP scenario the gravitational wave background spectra can be observed by future space gravitational wave antennas. On the other hand, when the dark pion is the SIMP dark matter with the constraints for the chiral perturbative limit and pion-pion scattering cross section, the chiral phase transition becomes crossover and then the gravitational waves are not produced.
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.)
Pion-pair production by two photons
International Nuclear Information System (INIS)
Terazawa, Hidezumi.
1994-07-01
The cross section for pion-pair production by two photons is calculated approximately by using the low energy theorem previously derived from partially-conserved-axial-vector-current hypothesis and current algebra, and found to agree very well with the experimental data recently obtained by the Mark II, TPC/Two-Gamma and CLEO Collaborations. (author)
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.)
International Nuclear Information System (INIS)
Ermekov, N.T.; Korotkikh, V.L.; Starkov, N.I.
1981-01-01
For the purpose of studying the channel contribution with low-lying level excitation in silicon nucleus into the differential cross section of the reaction the π - + 28 Si→π - +π - +π + + 28 Si reaction is investigated at the bombarding 16 GeV/c pion momentum. The calculation of differential cross sections on the basis of the Glauber model with a factorizing nucleus density is performed. The found parameters of nuclear densities are tabulated. The investigated reaction differential cross sections are calculated with account of coherent production as well as the channel with 2 + (1.78 MeV) level excitation. The calculated differential cross sections values integrated by the effective mass of the produced three-pion system (0.9 GeV + , 1.78 MeV)=0.25 mb are obtained. It is shown that filling the diffraction minimum in three-pion production differential cross section for ''alive'' silicon target is due to contribution from events with the excitation of the low-lying level 2 + (1.78 MeV) [ru
The H(n,n) cross section in the 20 MeV to 350 MeV range
International Nuclear Information System (INIS)
1997-01-01
The differential H(n,n) cross section has been used as a standard relative to which other neutron emission cross sections, e.g., elastic or inelastic scattering, have been measured in several Mev region and these measured values are compared with the VL40 solution of R. Arndt, and R.L. Workman, Nuclear Data Standards for Nuclear Measurements, H. Conde (ed.). NEANDC-311, INDC (SEC)-101, 1992, p. 17. For hydrogen, the differential elastic scattering cross section can be directly related to the total cross section, since no other channels of importance are open below the pion production threshold at about 280 MeV (the capture and Bremsstrahlung cross section are very small). 16 refs, 3 figs
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.
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...
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...
Rising pion inclusive cross section and n anti n cluster production
International Nuclear Information System (INIS)
Chiu, C.B.; Tow, D.M.
1976-05-01
It is argued that the reason for π - inclusive cross section to rise in the ISR energies is due to the threshold production of nucleon-antinucleon clusters. Such contributions are formulated and calculated at π - . Our results can account for the observed rise
Triple-differential cross sections of the (π+/,pp) reaction on lithium isotopes
International Nuclear Information System (INIS)
Rieder, R.; Barnes, P.D.; Bassalleck, B.
1985-01-01
The (π + ,pp) reactions on 6 Li and 7 Li have been studied at T/sub π/ = 59.4 MeV with high resolution. The first triple-differential cross sections for these reactions are presented. The data are fitted to a T-matrix and compared to the π + d → pp reaction. A model in which the pion is absorbed on a 3 S 1 (pn) pair in the lithium nucleus describes many features of the data very well. An extrapolation of our data into unmeasured regions of phase space suggests that about 60% of the pion absorption cross section on 6 Li at 59.4 MeV goes into the (π + ,pp) channel. One surprising feature of the data is that the 6 Li(π + ,pp) 4 He (2 - ) transition at 22.1 MeV excitation is strongly populated, similar to what is observed in the 6 Li(d,α) 4 He reaction. This transition involves removing one nucleon from the 1p shell and one from the 1s shell. 25 refs., 15 figs., 3 tabs
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...
Interaction of slow pions with atomic nuclei
International Nuclear Information System (INIS)
Troitskij, M.A.; Tsybul'nikov, A.V.; Chekunaev, N.I.
1984-01-01
Interactions of slow pions with atomic nuclei near to pion condensation are investigated. From comparison of experimental data with the theoretical calculation results on the basis of precise microscopic approach not bound with the random phase approximation (RPA) nuclear matter fundamental parameters near a critical point can be found. Optical potential of slow pions in nuclei, πN-scattering amplitudes and lengths, π-atom level isotopic shift, phenomenon of single-nucleon pion absorption by nucleus, phenomenon of nuclear critical opalescence are considered. The results of πN-scattering lengths calculation, sup(40-44)Ca, sup(24-29)Mg, sup(16-18)O π-atom level shift are presented. It is shown that the presence of π-condensate in nuclei can explain the observed suppression of p-wave potential terms. The phenomenon of single-nucleon pion absorption by nucleus is one of direct experiments which permits to reveal the π-condensate. The nuclear opalescence phenomenon is manifested in increase of pion photoproduction reaction cross section for account of nucleus proximity to π-condensation as compared with the calculated in the Fermi-gas model. The suggested method for calculating precondensate phenomena operates the better, the nearer is the system to the condensation threshold whereas the RPA method in this region is inapplicable
Exclusive channels in semi-inclusive production of pions and kaons
International Nuclear Information System (INIS)
Markus Diehl; Wolfgang Kugler; Andreas Schaefer; Christian Weiss
2005-01-01
We investigate the role of exclusive channels in semi-inclusive electroproduction of pions and kaons. Using the QCD factorization theorem for hard exclusive processes we evaluate the cross sections for exclusive pseudoscalar and vector meson production in terms of generalized parton distributions and meson distribution amplitudes. We investigate the uncertainties arising from the modeling of the nonperturbative input quantities. Combining these results with available experimental data, we compare the cross sections for exclusive channels to that obtained from quark fragmentation in semi-inclusive deep inelastic scattering. We find that rho0 production is the only exclusive channel with significant contributions to semi-inclusive pion production at large z and moderate Q2. The corresponding contribution to kaon production from the decay of exclusively produced phi and Kstar is rather small
Exclusive channels in semi-inclusive production of pions and kaons
Energy Technology Data Exchange (ETDEWEB)
Markus Diehl; Wolfgang Kugler; Andreas Schaefer; Christian Weiss
2005-06-01
We investigate the role of exclusive channels in semi-inclusive electroproduction of pions and kaons. Using the QCD factorization theorem for hard exclusive processes we evaluate the cross sections for exclusive pseudoscalar and vector meson production in terms of generalized parton distributions and meson distribution amplitudes. We investigate the uncertainties arising from the modeling of the nonperturbative input quantities. Combining these results with available experimental data, we compare the cross sections for exclusive channels to that obtained from quark fragmentation in semi-inclusive deep inelastic scattering. We find that rho0 production is the only exclusive channel with significant contributions to semi-inclusive pion production at large z and moderate Q2. The corresponding contribution to kaon production from the decay of exclusively produced phi and Kstar is rather small.
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
Azimuthal correlations of pions in relativistic heavy ion collisions at 1 GeV/nucl
International Nuclear Information System (INIS)
Bass, S.A.; Hartnack, C.; Nantes Univ., 44; Stoecker, H.; Greiner, W.
1995-01-01
Triple differential cross sections of pions in heavy ion collisions at 1 GeV/nucl. are studied with the IQMD model. After discussing general properties of Δ resonance and pion production we focus an azimuthal correlations: At projectile- and target-rapidities we observe an anticorrelation in the in-plane transverse momentum between pions and protons. At c.m.-rapidity, however, we find that high p t pions are being preferentially emitted perpendicular to the event-plane. We investigate the causes of those correlations and their sensitivity on the density and momentum dependence of the real and imaginary part of the nucleon and pion optical potential. (orig.)
Measurement of the charged-pion polarizability.
Adolph, C; Akhunzyanov, R; 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; 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; Dünnweber, W; Dziewiecki, M; Efremov, A; Elia, C; Eversheim, P D; Eyrich, W; Faessler, M; Ferrero, A; Filin, A; Finger, M; Finger, 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; 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; 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
2015-02-13
The COMPASS collaboration at CERN has investigated pion Compton scattering, π(-)γ→π(-)γ, at center-of-mass energy below 3.5 pion masses. The process is embedded in the reaction π(-)Ni→π(-)γNi, which is initiated by 190 GeV pions impinging on a nickel target. The exchange of quasireal 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 polarizability is determined to be α(π)=(2.0±0.6(stat)±0.7(syst))×10(-4) fm(3) under the assumption α(π)=-β(π), which relates the electric and magnetic dipole polarizabilities. 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 found in agreement with the expectation from chiral perturbation theory. An additional measurement replacing pions by muons, for which the cross-section behavior is unambiguously known, was performed for an independent estimate of the systematic uncertainty.
Isospin violation in pion-kaon scattering
International Nuclear Information System (INIS)
Kubis, Bastian; Meissner, Ulf-G.
2002-01-01
We consider strong and electromagnetic isospin violation in near-threshold pion-kaon scattering. At tree level, such effects are small for all physical channels. We work out the complete one-loop corrections to the process π - K + →π 0 K 0 . They come out rather small. We also show that the corresponding radiative cross section is highly suppressed at threshold
Determination of the Pion Charge Form Factor at Q2=1.60 and 2.45 (GeV/c)2
International Nuclear Information System (INIS)
Horn, T.; Beise, E. J.; Breuer, H.; Chang, C. C.; King, P. M.; Liu, J.; Roos, P. G.; Aniol, K.; Margaziotis, D. J.; Arrington, J.; Holt, R. J.; Potterveld, D.; Reimer, P.; Zheng, X.; Barrett, B.; Sarty, A.; Blok, H. P.; Tvaskis, V.; Boeglin, W.; Markowitz, P.
2006-01-01
The 1 H(e,e ' π + )n cross section was measured at four-momentum transfers of Q 2 =1.60 and 2.45 GeV 2 at an invariant mass of the photon nucleon system of W=2.22 GeV. The charged pion form factor (F π ) was extracted from the data by comparing the separated longitudinal pion electroproduction cross section to a Regge model prediction in which F π is a free parameter. The results indicate that the pion form factor deviates from the charge-radius constrained monopole form at these values of Q 2 by one sigma, but is still far from its perturbative quantum chromodynamics prediction
Many-pion production in π+d reactions at 15 GeV/c
International Nuclear Information System (INIS)
Hagopian, V.; Gluch, D.; Hagopian, S.; Horne, C.P.; Jenkins, M.; Lannutti, J.E.; Williams, P.K.; Wind, B.; Cohn, H.O.; Bugg, W.M.; Condo, G.T.; Handler, T.; Hart, E.L.
1979-01-01
The average number of charged pions produced in π + d reactions at 15-GeV/c π + momentum is 3.6 +- 0.1 and the average number of π 0 's is 1.9 +- 0.2. The average number of π 0 's produced is essentially independent of the number of charged pions. About 45% of the events have four or more charged pions in the final state. The exclusive final states with four or more charged pions with zero or one π 0 are presented and compared with modified phase-space background computations. Other than the well-known resonances, such as the rho 0 , no new peaks have been observed. Coherently produced multipion systems with up to seven pions are also discussed. Detailed cross-section information for every final state is presented
One, two and three pion production in pd collisions at 19 GeV/c
International Nuclear Information System (INIS)
Bakken, V.; Jacobsen, T.; Olsson, J.E.; Johansson, H.; Lundborg, P.; Sellden, B.; Maekelae, J.; Pimiae, H.; Sundell, E.
1976-04-01
Cross sections for coherent and non-coherent production of one, two and three pions in pd reactions at 19 GeV/c are presented. The mass distribution of the two pion non-coherent channels are studied. Strong single Δ(1236) and also some double Δ production are observed. Clear evidence for rho production is seen. (Auth.)
Analysis of pion production data from E-802 at 14.6 GeV/c using ARC
International Nuclear Information System (INIS)
Kahana, D.; Torun, Yagmur
1995-07-01
We compared the invariant cross sections for pion production by a 14.6 GeV/c proton beam on Be, Al, Cu and Au targets from the measurements of Abbott et.al. with predictions of the ARC program. The agreement was found to be good in the region where data exists. Most pions are found at low momenta in the lab frame. Unfortunately very little data exists for low momentum pions
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...
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
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.
On the problem of bound states of pions and neutrons
International Nuclear Information System (INIS)
Gudima, K.K.; Karnaukhov, V.A.
1992-01-01
The problem of existence of the bound states of negative pions and neutrons has been widely discussed for the last years. It is considered possibilities of the experimental observation of pion-neutron clusters, if they do exist, in nucleus-nucleus collisions. The yields of exotic fragments π -Z n A in the interactions of 12 C and 56 Fe with 208 Pb at the energies from 0.3 to 3.7 GeV per nucleon are calculated. For 40 Ar+ 238 U and 139 La+ 238 U collisions the calculations were performed at the energied of 1.8 GeV and 1.3 GeV per nucleon, respectively. These calculations were performed in the framework of the coalescence mechanism with the differential cross sections for pion and neutron production generated by firestreak model. The differential cross sections for production of π -1 n -2 , π -2 N 2 , π - n 4 , π -4 n 6 , and π -12 n 6 were calculated. It is shown that the use of very heavy projectiles like 56 Fe and 139 La has a great advantage in the experimental search for the exotic clusters. 20 refs.; 8 figs
The effect of meson exchange on the forward cross section for d(γ,p)n
International Nuclear Information System (INIS)
Jaus, W.; Woolcock, W.S.
1981-01-01
We have investigated the effect of meson exchange on the theoretical calculation of the cross section for the photodisintegration of the deuteron in the forward direction, in the hope of reducing the present large discrepancy between theory and experiment. Two recent papers reporting a significant reduction in the discrepancy were found to have a sign error; when pseudoscalar πNN coupling is used the effect of one-pion exchange is to increase the discrepancy. We have calculated the one-pion and two-pion exchange effects on the E1 transitions using pseudovector πNN coupling and the resulting correction is small and in the right direction. Thus, assuming the reliability of both theory and experiment, our calculation provides a strong argument in favour of using PV rather than PS πNN coupling in calculating meson exchange effects in nuclear processes. We have found that the effect of the exchange of rho- and ω-mesons is very small. Meson exchange effects change the normalization of the deuteron wave function and cause a further small reduction in the calculated cross section. Since the corrections to the M1 transitions are expected to be very small, it seems unlikely that meson exchange effects can account for the discrepancy between theory and experiment. (orig.)
Data on the electromagnetic pion form factor and p-wave
International Nuclear Information System (INIS)
Dubnicka, S.; Meshcheryakov, V.A.; Milko, J.
1980-01-01
The pion form factor absolute value data (free of the omega meson contribution) are unified with the P-wave isovector ππ phase shift. The resultant real and imaginary parts of the pion form factor are described by means of the Pade approximation. All the data, which involve the pion form factor experimental points from the range of momenta - 0.8432 GeV 2 2 , the pion charge radius, and the P-wave isovector ππ phase shift in the elastic region (including also the generally accepted value of the scattering length) are mutually consistent. The data themselves through the Pade approximation reveal that the aforementioned consistency can be achieved only if the pion form factor left-hand cut from the second Riemann sheet is taken into account. Almost in all of the considered Pade approximations one stable pion form factor zero is found in the space-like region, which might indicate the existence of a diffraction minimum in the differential cross section for elastic e - π scattering as a consequence of the constituent structure of the pion like in the case of the electron elastic scattering on nuclei
Isospin violation in pion-kaon scattering
Energy Technology Data Exchange (ETDEWEB)
Kubis, Bastian E-mail: b.kubis@fz-juelich.de; Meissner, Ulf-G. E-mail: ulf-g.meissner@fz-juelich.de
2002-03-11
We consider strong and electromagnetic isospin violation in near-threshold pion-kaon scattering. At tree level, such effects are small for all physical channels. We work out the complete one-loop corrections to the process {pi}{sup -}K{sup +}{yields}{pi}{sup 0}K{sup 0}. They come out rather small. We also show that the corresponding radiative cross section is highly suppressed at threshold.
Radiative pion-proton scattering in the static Chew--Low model
International Nuclear Information System (INIS)
Ho-Kim, Q.; Lavine, J.P.
1975-01-01
The results of a nonrelativistic calculation of π/sup +-/-proton bremsstrahlung cross sections at the pion laboratory kinetic energy of 298 MeV for backward photon angles is presented. The πp interaction is described by the static Chew-Low model
Measurement of dijet cross sections in deep inelastic ep scattering at HERA
Energy Technology Data Exchange (ETDEWEB)
Theedt, Thorben
2009-11-15
Dijet cross sections have been measured in deep inelastic neutral current electron-proton scattering at HERA. Cross sections have been measured differentially as functions of the photon virtuality, Q{sup 2}, the scaling variable, Bjorken x, the mean transverse jet energy, E{sub T}, the invariant dijet mass, M{sub jj}, the difference in jet pseudorapidity, {eta}'= vertical stroke {eta}{sup jet{sub 1}}-{eta}{sup jet{sub 2}} vertical stroke and the momentum fraction, {xi}. Cross sections as function of {xi} have also been measured in different regions of the photon virtuality. The analysed data were recorded at a centre-of-mass energy of 318 GeV with the ZEUS detector in the years 1998, 1999, and 2000 and correspond to an integrated luminosity of 81.74 pb{sup -1}. The phase space of the analysis is defined by 125pion study, in which single pion events were used to investigate the response of the simulated detector. (orig.)
Distortion effects in pion-induced knock-out reactions
International Nuclear Information System (INIS)
Jain, B.K.
The cross-section for (π + ,π + p) reaction on 12 C is calculated in DWIA at 100 and 180 MeV incident energy. The effect of pion distortion is found to be strong. Around 180 MeV the effect is strongly absorptive while around 10O MeV it is mainly dispersive. (auth.)
Zhang, Dun
Neutrino interactions in the detectors of long baseline oscillation experiments are analyzed to determine the neutrino flavor and energy spectrum, allowing the neutrino mass ordering and mixing parameters to be determined. For neutrino interactions below the pion production threshold, the dominant reaction is charged current quasi-elastic (CCQE) scattering. Oscillation experiments are made of heavy nuclei so the QE process occurs on nucleons that are embedded in the nuclear environment. Predictions of the QE cross-section suffer from significant uncertainties due to our understanding of that nuclear environment and the way it is probed by the weak interaction. I have developed a new technique to reduce the inelastic background to CCQE process by identifying the "Michel electrons" produced by pions. Additionally an updated neutrino flux was used to extract the cross-section and estimates for some sources of systematic uncertainties have been improved. The measured cross-section is compared to several theoretical models and the effect that the signal definition ("CCQE" vs "CCQE-like") has on the measurement is also explored.
Radiative pion-proton scattering in the static Chew-Low model
International Nuclear Information System (INIS)
Ho-Kim, Q.; Lavine, J.P.
1976-01-01
The results of a non-relativistic calculation of π +- -proton bremsstrahlung cross-sections at the pion laboratory kinetic energy of 298 MeV for backward photon angles are presented. The πp interaction is described by the static Chew-Low model. (Auth.)
International Nuclear Information System (INIS)
Iwamoto, Yosuke; Shigyo, Nobuhiro; Satoh, Daiki
2002-01-01
Neutron-production double-differential cross sections for 870-MeV π + and π - and 2.1-GeV π + mesons incident on iron and lead targets were measured with NE213 liquid scintillators by time-of-flight technique. NE213 liquid scintillators 12.7 cm in diameter and 12.7 cm thick were placed in directions of 15, 30, 60, 90, 120 and 150deg. The typical flight path length was 15 m. Neutron detection efficiencies were derived from the calculation results of SCINFUL and CECIL codes. The experimental results were compared with the JAM code. The double differential cross sections calculated by the JAM code disagree with experimental data at neutron energies below about 30 MeV. JAM overestimates π + -incident neutron-production cross sections in forward angles at neutron energies of 100 to 500 MeV. (author)
Effect of pion external distortion on low energy pion double-charge-exchange
International Nuclear Information System (INIS)
Khankhasaev, M.Kh.; Kurmanov, Zh.B.; Johnson, M.B.
1993-01-01
The effects of the external pion distortion for iso-elastic charge exchange scattering (within the framework of the isospin invariant optical model) is considered. An approximated method of taking into account the distortion based on the separable expansion of the optical potential in momentum space is developed. The result of external distortions for sequential scattering 14 C(π + , π - ) 14 O at 50 MeV is presented. It is shown that this distortion gives a small enhancement to forward and reduced the differential cross sections at large angels. 22 refs., 5 figs., 1 tab
Production of pions and anomalous projectile fragments in heavy ion collisions
International Nuclear Information System (INIS)
Noren, B.
1988-05-01
Results are presented from investigations of the mean free path (mfp) of multiply charged fragments, produced by 1.8 A GeV argon nuclei. The mfp's have been studied experimentally, and no dependence of the mfp on the distance from the preceeding collision is observed. In a Monte Carlo simulation, the mfp estimators are investigated for different statistics, with or without an enhanced reaction probability. Intermediate energy heavy ion collisions have been studied using the carbon beam produced at the CERN SC-accelerator. Cross-sections for pion + and pion - have been measured over a wide range of angles and targets. Also, coincidence measurements with projectile-like fragments have been performed. The pion - /pion + ratio has been studied for C+Li, C+C, C+Pb, C+ 116 Sn and C+ 124 Sn. Inconsistencies in the target mass dependence of the pion yield disappear if a correction for reabsorption in the target nucleus is included. The projectile breakup is significantly stronger for pion producing collisions than for the average collision, thus indicating a much stronger abundance of central collisions. (With 32 refs.) (author)
Design and simulation of the nuSTORM pion beamline
Energy Technology Data Exchange (ETDEWEB)
Liu, A., E-mail: aoliu@fnal.gov; Neuffer, D.; Bross, A.
2015-11-21
The nuSTORM (neutrinos from STORed Muons) proposal presents a detailed design for a neutrino facility based on a muon storage ring, with muon decay in the production straight section of the ring providing well defined neutrino beams. The facility includes a primary high-energy proton beam line, a target station with pion production and collection, and a pion beamline for pion transportation and injection into a muon decay ring. The nuSTORM design uses “stochastic injection”, in which pions are directed by a chicane, referred to as the Orbit Combination Section (OCS), into the production straight section of the storage ring. Pions that decay within that straight section provide muons within the circulating acceptance of the ring. The design enables injection without kickers or a separate pion decay transport line. The beam line that the pions traverse before being extracted from the decay ring is referred to as the pion beamline. This paper describes the design and simulation of the pion beamline, and includes full beam dynamics simulations of the system.
Total disintegration of three-nucleon nuclei in charged-pion photo-production
International Nuclear Information System (INIS)
Dzhibuti, R.I.; Kezerashvili, R.Y.
1984-01-01
The total disintegration of three-nucleon nuclei in charged-pion photo-production is studied within the framework of the microscopic approach based on the method of hyperspherical functions. The initial and final nuclear states are described using the same NN potentials. The differential and total cross sections are calculated using various NN potentials. It is shown that the cross sections are sensitive to the form of the NN interaction and to the final-state interaction of the three nucleons. It is found that the cross section for π - meson production is systematically larger than the cross section for π + meson production. The importance of an experimental investigation of these reactions is shown
Radiative corrections to the hadronic cross-section measurement at DA{phi}NE
Energy Technology Data Exchange (ETDEWEB)
Khoze, V.A. [Durham Univ. of Durham, Durham (United Kingdom). Dept. of Physics; Konchatnij, M.I.; Merenkov, NP.; Shekhovzova, O.N. [National Science Centre Kharkov Institute of Physics and Technology, Karkhov (Ukraine); Pancheri, G. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, Frascati, RM (Italy); Trentadue, L. [Parma Univ., Parma (Italy). Dipt. di Fisica
2000-07-01
The hadronic invariant mass distribution for the process of electron--positron annihilation into a pair of charged pions accompanied by a photon radiated from the initial state has been studied for the region of DA{phi}NE energies. The Born cross-section and the electromagnetic radiative corrections to it are calculated for realistic conditions of the KLOE detector. The dependence on the physical parameters which define the event selection is obtained.
Measurement of hadronic exclusive cross sections in e+e- annihilation from 1.42 to 2.20 GeV
International Nuclear Information System (INIS)
Bacci, C.; De Zorzi, G.; Penso, G.; Stella, B.; Baldini Celio, R.; Battistoni, G.; Capon, G.; Del Fabbro, R.; Iarocci, E.; Murtas, G.P.
1981-01-01
Total cross sections for reactions e + e - → π + π - π 0 , π + π - 2π 0 , 2π + 2π - π 0 , 2π + 2π - 2π 0 , 3π + 3π - have been measured in the total c.m. energy range 1.42-2.20 GeV. Partial R = sigmasub(had)/sigmasub(μ + μ - ) values for two and four produced charged pions, and cross sections for positive and negative G-parity states are also reported. (orig.)
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
Large-angle theory for pion-nucleus scattering at high energies
International Nuclear Information System (INIS)
Hoock, D.W. Jr.
1978-01-01
An approximate solution for high-energy, projectile-nucleus, multiple scattering is developed from the exact Watson series and applied to pion scattering for 12 C and 4 He. Agreement with measured differential cross sections available from the literature for the range 150 to 260 MeV pion laboratory energies is surprisingly good. The approximation method expands the propagators of the Watson series about the transverse component of the momentum transfer. Contributions of each of the first two terms to double scattering from a Gaussian potential are compared to the exact solution. The purely plane-wave propagation produces a scattering amplitude that agrees to order (k 0 a) -1 with the exact solution at the forward and backward directions at high energies. The second (off-axis) propagation term produces an amplitude that is one order smaller at forward angles and two orders smaller at 180 0 than the exact amplitude. At intermediate angles it is of the same order. The general multiple-scattering series is approximated with selection of plane-wave propagation as the fundamental process at large and small angles. This model suggests that a single nucleon accepts most of the momentum transfer for backward scattering. The resulting multiple-scattering formula agrees with the well-known high-energy eikonal theory at small angles and the backward-angle scattering formula of Chen at exactly 180 0 . A lowest-order formula that includes off-axis propagation is also derived. Predicted differential cross sections are found to be sensitive to nucleon motion and binding. For 4 He the effect of the nuclear potential on the pion kinetic energy is also examined and found to produce significant changes in the predicted cross sections
Dispersive analysis of the pion transition form factor
Hoferichter, M.; Kubis, B.; Leupold, S.; Niecknig, F.; Schneider, S. P.
2014-11-01
We analyze the pion transition form factor using dispersion theory. We calculate the singly-virtual form factor in the time-like region based on data for the cross section, generalizing previous studies on decays and scattering, and verify our result by comparing to data. We perform the analytic continuation to the space-like region, predicting the poorly-constrained space-like transition form factor below , and extract the slope of the form factor at vanishing momentum transfer . We derive the dispersive formalism necessary for the extension of these results to the doubly-virtual case, as required for the pion-pole contribution to hadronic light-by-light scattering in the anomalous magnetic moment of the muon.
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
Pion-induced fission of 209Bi and 119Sn: measurements, calculations, analyses and comparison
International Nuclear Information System (INIS)
Rana, M.A.; Sher, G.; Manzoor, S.; Shehzad, M.I.
2011-01-01
Cross-sections for the π - -induced fission of 209 Bi and 119 Sn have been measured using the most sensitive CR-39 solid-state nuclear track detector. In experiments, target–detector stacks were exposed to negative pions of energy 500, 672, 1068, and 1665 MeV at the Brookhaven National Laboratory, USA. An important aspect of the present paper is the comparison of pion-induced fission fragment spectra of above mentioned nuclei with the spontaneous fission fragment spectra of 252 Cf. This comparison is made in terms of fission fragment track lengths in the CR-39 detectors. Measurement results are compared with calculations of Monte Carlo and statistical weight functions methods using the computer code CEM95. Agreement between measurements and calculations is fairly good for 209 Bi target nuclei whereas it is indigent for the case of 119 Sn. The possibilities of the trustworthy calculations, using the computer code CEM95, comparable with measurements of pion-induced fission in intermediate and heavy nuclei are explored by employing various systematics available in the code. Energy dependence of pion-induced fission in 119 Sn and 209 Bi is analyzed employing a newly defined parameter geometric-size-normalized fission cross-section (χ f g ). It is found that the collective nuclear excitations, which may lead to fission, become more probable for both 209 Bi and 119 Sn nuclei with increasing energy of negative pions from 500 to 1665 MeV. (author)
Experiments on the nuclear interactions of pions and electrons
International Nuclear Information System (INIS)
Minehart, R.C.; Ziock, K.O.H.
1989-07-01
We have completed the analysis of the 3 He(π + ,pp)n reaction, and are working on the analysis of data for the 3 He(π - ,pn)p reaction. An experiment to study the π + d → 2p reaction at LAMPF was successful in studying incident pion energies as low as 6 MeV. Preliminary results have been reported, and work is continuing to improve the accuracy in the calculation of the fraction of pions in the incident beam. A proposal has been accepted by LAMPF for a new experiment, scheduled to run in the summer of 1990, to study pion absorption in 3 He and 4 He using an extensive scintillator time-of-flight system capable of detecting neutrons as well as charged particles. We are continuing to analyze data obtained in PSI in the search for the admixture of massive neutrinos in pion decay and have continued the search for fractionally charged particles. We are also fully involved in some major collaborations: the search for the decay μ + → e + + γ, and the study of anti-proton absorption in heavy nuclei. We are taking part in a U.Va.-PSI collaboration to measure pion beta decay to an accuracy of about 1%, using a large acceptance CsI detector to measure the π 0 following decay of stopped π + mesons. We have also been working on experiments to study electron scattering, using the SLAC-NPAS facility for nuclear physics and the electron accelerator at SACLAY in France. Data from experiment NE-9 at SLAC are being analyzed. This experiment, which was run near the end of 1987, is intended to separate the transverse and longitudinal cross sections for inclusive electron scattering in the QFS region. Experiment NE-8 measured the cross section for photo-disintegration of the deuteron in the GeV range. Some design work was carried out this year on Experiment NE-16 at SLAC, a study of the (e,e'p) reaction in 4 He, expected to run late in 1990
Pion-pion interactions in particle physics
Energy Technology Data Exchange (ETDEWEB)
Martin, B R; Morgan, D; Shaw, G
1976-01-01
The aim of the book is to review the experimental and theoretical work on the processes involving pion-pion interactions. Sources of information on pion-pion scattering are examined, including pion production, dipion exchange, and weak and electromagnetic interactions. The theory and models of pion-pion scattering are discussed with reference to fixed momentum transfer, partial wave amplitudes, models and phenomenology, dynamical and field theoretic models, finite-energy sum rules, duality and the Veneziano model, resonance spectra and lastly, predictions from current algebra.
A Study of Charged Current Single Charged Pion Productions on Carbon in a Few-GeV Neutrino Beam
Energy Technology Data Exchange (ETDEWEB)
Hiraide, Katsuki [Kyoto Univ. (Japan)
2009-01-01
Understanding single charged pion production via neutrino-nucleus charged current interaction in the neutrino energy region of a few GeV is essential for future neutrino oscillation experiments since this process is a dominant background for v_{μ} → v_{x} oscillation measurements. There are two contributions to this process: single pion production via baryonic resonance (v_{μ}N → μ^{-} Nπ^{+}) and coherent pion production interacting with the entire nucleus (v_{μ}A → μ^{-} Aπ^{+}), where N is nucleon in the nucleus and A is the nucleus. The purpose of the study presented in this thesis is a precise measurement of charged current single charged pion productions, resonant and coherent pion productions, with a good final state separation in the neutrino energy region of a few GeV. In this thesis, we focus on the study of charged current coherent pion production from muon neutrinos scattering on carbon, v_{μ} ^{12}C → μ^{-12}Cπ^{+}, in the SciBooNE experiment. This is motivated by the fact that without measuring this component first, the precise determination of resonant pion production cross section can not be achieved since the contribution of coherent pion production in the region of small muon scattering angle is not small. Furthermore, the coherent process is particularly interesting because it is deeply rooted in fundamental physics via Adler's partially conserved axial-vector current theorem. We took data from June 2007 until August 2008, in both the neutrino and antineutrino beam. In total, 2.52 x 10^{20} protons on target were collected. We have performed a search for charged current coherent pion production by using SciBooNE's full neutrino data set, corresponding to 0.99 x 10^{20} protons on target. No evidence for coherent pion production is observed. We set 90% confidence level upper limits on the cross section ratio
K+ nucleus total cross section experiment and nuclear medium effects
International Nuclear Information System (INIS)
Weiss, Ruth.
1992-11-01
The low momentum K + is the weakest of the available strongly interacting particles. It has a mean bee path in nuclear matter of about 6 fm which makes it a good probe for studying properties of the nuclear interior. It allows one to build a good microscopic optical potential which can be used to calculate K + nucleus elastic and total cross sections. In the latter case the calculated ratio R T =[σ tot (K + A)/A]/[σ tot (K + d)/2] can be expected to be more reliable because some uncertainties in K + N phase shifts will cancel. This ratio can also be measured more reliably than the total cross sections themselves because of cancellation of some systematic errors. We measured the total cross sections of K + on D, 6 Li, 12 C, 28 Si and 40 Ca from 488 to 714 MeV/c. The emphasis was placed on extracting values of R T with a precision of better than 2 percent. The total cross section ratios are found to lie significantly above those predicted by optical potential calculations with the usual nuclear medium corrections. This suggests that novel phenomena are taking place within the nucleus. Several models which incorporate such phenomena are discussed, including nucleon 'swelling', mass rescaling, nuclear pions, and relativistic effects. (author) 31 refs., 27 figs., 21 tabs.,
Charged-Current Neutral Pion production at SciBooNE
International Nuclear Information System (INIS)
Catala-Perez, J.
2009-01-01
SciBooNE, located in the Booster Neutrino Beam at Fermilab, collected data from June 2007 to August 2008 to accurately measure muon neutrino and anti-neutrino cross sections on carbon below 1 GeV neutrino energy. SciBooNE is studying charged current interactions. Among them, neutral pion production interactions will be the focus of this poster. The experimental signature of neutrino-induced neutral pion production is constituted by two electromagnetic cascades initiated by the conversion of the π 0 decay photons, with an additional muon in the final state for CC processes. In this poster, I will present how we reconstruct and select charged-current muon neutrino interactions producing π 0 's in SciBooNE.
International Nuclear Information System (INIS)
Engel, A.
1995-01-01
Delta excitation plays a prominent role in intermediate heavy reactions. In this paper, comment is made on the calculations done for pion-, photon- and nucleon-nucleus reactions using the Boltzmann-Uehling-Uhlenbeck (BUU) model and the antisymmetrized molecular dynamics (AMD) model. First, it is recalled how to include delta degrees in microscopic models in general. Then, the comparison of the microscopic calculation performed by the author with the experimental data is presented. Deltas in microscopic models are discussed. Pion-nucleus reactions have been studied since pion beams became available, especially for exploring the delta resonance in a nuclear medium. The dependence of pion absorption cross section on incident pion energy is shown. The photon-induced pion production in the resonance energy region was studied with the BUU model. The calculated results of neutral pion photo-production are shown. In both inelastic proton scattering and (p,n) charge exchange reaction, the excitation of delta resonance can be observed clearly in the experimental data. The results of the AMD calculation for 12 C(p,p') reaction are shown. (K.I.)
Multi-pion production in deuteron-proton collisions at COSY-ANKE
Energy Technology Data Exchange (ETDEWEB)
Mielke, Malte Marius
2014-07-01
The presented work is a contribution to the research on two- and three pion production in deuteron-proton collisions. Whereas the latter has received very little attention so far, the former is attracting the interest of particle physicists since several decades. An important reason for this is the appearance of the so-called ABC effect, a striking enhancement in the two-pion invariant mass spectrum near its threshold. There is strong evidence that this is related to the presence of nucleons and in the context of recent investigations it is even linked to an excitation of dibaryon resonances. The here presented results from an exclusive measurement of the dp→{sup 3}Heπ{sup +}π{sup -} reaction with the COSY-ANKE facility at an excess energy of 265 MeV benefit from high statistics as well as a good momentum resolution. Events with coincidentally detected {sup 3}Heπ{sup ±} and {sup 3}Heπ{sup +}π{sup -} combinations were used for the analysis. Various selection steps led to a very clean data sample. The limited geometrical acceptance of the ANKE detector was studied in detail in order to successfully elaborate a reliable correction method. Based on this, it was possible to determine differential and double differential cross sections for a large fraction of the backward {sup 3}He hemisphere. The derived invariant mass distributions do allow to illuminate further details of the two-pion production processes. Besides the prominent ABC enhancement, they reveal a significant difference in the behaviour of the positively and negatively charged pions, which is interpreted to be caused by π{sup +}π{sup -} isovector contributions. The total results are successfully described in terms of a N{sup *}(1440)→Δ(1232)→N decay chain. However, the isobar model surprisingly underestimates the charge difference at low two-pion invariant masses, indicating further contribution to the isovector channel. Investigations on the simultaneously measured dp→{sup 3}Heπ{sup +}
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
Evidence for pion absorption on four nucleons
International Nuclear Information System (INIS)
Rzehorz, B.; Backenstoss, G.; Dzemidzic, M.; Zagreb Univ.; Furic, M.; Zagreb Univ.; Hoffart, A.; Petkovic, T.; Zagreb Univ.; Ullrich, H.; Weyer, H.J.; Weiser, D.; Wildi, M.
1996-01-01
Experimental spectra from the coincident detection of three nucleons after the pion absorption in 4 He are displayed. The presence of a mechanism with four nucleons participating in the absorption process is made obvious. The total cross-sections for this absorption mode are: σ 4NA abs =(1.0±0.2)mb at T π =120 MeV and σ 4NA abs =(2.18± 0.65) mb at T π =210 MeV. (orig.)
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
Measurement of neutrino induced charged current neutral pion production cross section at SciBooNE
Energy Technology Data Exchange (ETDEWEB)
Catala-Perez, Juan [Univ. of Valencia (Spain)
2014-01-01
SciBooNE is a neutrino scattering experiment located in the Booster Neutrino Beam at Fermilab. It collected data from June 2007 to August 2008 to accurately measure muon neutrino and anti-neutrino cross sections on carbon around 1 GeV neutrino energy. In this thesis we present the results on the measurement of the muon neutrino cross section resulting in a μ^{-} plus a single π^{0} final state (CC- π^{0} channel). The present work will show the steps taken to achieve this result: from the reconstruction improvements to the background extraction. The flux-averaged CC - π^{0} production cross section measurement obtained in this thesis < σCC- π^{0} > Φ = (5.6 ± 1.9_{fit} ± 0.7_{beam} ± 0.5_{int} - 0.7_{det}) × 10^{-40} cm^{2}/N at an average energy of 0.89 GeV is found to agree well both with the expectation from the Monte Ca
Quasi-free pion single charge exchange
International Nuclear Information System (INIS)
Ouyang, J.
1992-12-01
Cross sections for the quasi-free (QF) region for pion single charge exchange (SCX) were measured with beams of 475 MeV π - , 500 MeV π ± , and 400 MeV π - , with most data at 500 MeV π ± . The LAMPF π 0 spectrometer and a proton detector arm were placed on each side of the beam with different scattering angles. Up to twelve targets, from hydrogen to bismuth, were used. Both inclusive and coincidence measurements were performed. The extraction of peak shape and cross section for the QF peak, the effective number of nucleons involved in the reaction, mass dependence, and angular dependence were studied for the inclusive measurement. Calculations with the local random phase approximation (RPA) were used to understand the inclusive experimental results. A collection of experimental results is given for both inclusive and coincidence measurements
Additive quark model and double scattering of pions and protons in deuterium
International Nuclear Information System (INIS)
Bialas, A.; Czyz, W.; Kisielewska, D.
1981-01-01
It is shown that the additive quark model is compatible with the data on double scattering of pions and protons in deuterium. The cross-section for interaction of the hadrons created in the first collision with the second nucleon of the target is determined to be 20-25 mb. (author)
Measurement of dijet cross sections for events with a leading neutron in photoproduction at HERA
International Nuclear Information System (INIS)
Breitweg, J.; Chekanov, S.; Derrick, M.; Krakauer, D.; Magill, S.; Musgrave, B.; Pellegrino, A.; Repond, J.; Stanek, R.; Yoshida, R.; Mattingly, M.C.K.; Antonioli, P.; Bari, G.; Basile, M.; Bellagamba, L.; Boscherini, D.; Bruni, A.; Bruni, G.; Cara Romeo, G.; Cifarelli, L.; Cindolo, F.; Contin, A.; Corradi, M.; De Pasquale, S.; Giusti, P.; Iacobucci, G.; Levi, G.; Margotti, A.; Massam, T.; Nania, R.; Palmonari, F.; Pesci, A.; Sartorelli, G.; Zichichi, A.; Amelung, C.; Bornheim, A.; Brock, I.; Coboeken, K.; Crittenden, J.; Deffner, R.; Hartmann, H.; Heinloth, K.; Hilger, E.; Irrgang, P.; Jakob, H.-P.; Kappes, A.; Katz, U.F.; Kerger, R.; Paul, E.; Rautenberg, J.; Schnurbusch, H.; Stifutkin, A.; Tandler, J.; Voss, K.C.; Weber, A.; Wieber, H.; Bailey, D.S.; Barret, O.; Brook, N.H.; Foster, B.; Heath, G.P.; Heath, H.F.; Rodrigues, E.; Scott, J.; Tapper, R.J.; Capua, M.; Schioppa, M.; Susinno, G.; Jeoung, H.Y.; Kim, J.Y.; Lee, J.H.; Lim, I.T.; Ma, K.J.; Pac, M.Y.; Caldwell, A.; Liu, W.; Liu, X.; Mellado, B.; Paganis, S.; Sampson, S.; Schmidke, W.B.; Sciulli, F.; Chwastowski, J.; Eskreys, A.; Figiel, J.; Klimek, K.; Olkiewicz, K.; Piotrzkowski, K.; Przybycien, M.B.; Stopa, P.; Zawiejski, L.; Bednarek, B.; Jelen, K.; Kisielewska, D.; Kowal, A.M.; Kowalski, T.; Przybycien, M.; Rulikowska-Zarebska, E.; Suszycki, L.; Szuba, D.; Kotanski, A.; Bauerdick, L.A.T.; Behrens, U.; Bienlein, J.K.; Borras, K.; Chiochia, V.; Dannheim, D.; Desler, K.; Drews, G.; Fox-Murphy, A.; Fricke, U.; Goebel, F.; Goers, S.; Goettlicher, P.; Graciani, R.; Haas, T.; Hain, W.; Hartner, G.F.; Hebbel, K.; Hillert, S.; Koch, W.; Koetz, U.; Kowalski, H.; Labes, H.; Loehr, B.; Mankel, R.; Martens, J.; Martinez, M.; Milite, M.; Moritz, M.; Notz, D.; Petrucci, M.C.; Polini, A.; Rohde, M.; Savin, A.A.; Schneekloth, U.; Selonke, F.; Sievers, M.; Stonjek, S.; Wolf, G.; Wollmer, U.; Youngman, C.; Zeuner, W.; Coldewey, C.; Lopez-Duran Viani, A.; Meyer, A.; Schlenstedt, S.; Straub, P.B.; Barbagli, G.; Gallo, E.; Parenti, A.; Pelfer, P.G.; Bamberger, A.; Benen, A.; Coppola, N.; Eisenhardt, S.; Markun, P.; Raach, H.; Woelfle, S.; Bussey, P.J.; Bell, M.; Doyle, A.T.; Glasman, C.; Lee, S.W.; Lupi, A.; Macdonald, N.; McCance, G.J.; Saxon, D.H.; Sinclair, L.E.; Skillicorn, I.O.; Waugh, R.; Bohnet, I.; Gendner, N.; Holm, U.; Meyer-Larsen, A.; Salehi, H.; Wick, K.; Carli, T.; Garfagnini, A.; Gialas, I.; Gladilin, L.K.; Kcira, D.; Klanner, R.; Lohrmann, E.; Goncalo, R.; Long, K.R.; Miller, D.B.; Tapper, A.D.; Walker, R.; Cloth, P.; Filges, D.; Ishii, T.; Kuze, M.; Nagano, K.; Tokushuku, K.; Yamada, S.; Yamazaki, Y.; Ahn, S.H.; Lee, S.B.; Park, S.K.; Lim, H.; Son, D.; Barreiro, F.; Garcia, G.; Gonzalez, O.; Labarga, L.; del Peso, J.; Redondo, I.; Terron, J.; Vazquez, M.; Barbi, M.; Corriveau, F.; Hanna, D.S.; Ochs, A.; Padhi, S.; Stairs, D.G.; Wing, M.; Tsurugai, T.; Antonov, A.; Bashkirov, V.; Danilov, M.; Dolgoshein, B.A.; Gladkov, D.; Sosnovtsev, V.; Suchkov, S.; Dementiev, R.K.; Ermolov, P.F.; Golubkov, Yu.A.; Katkov, I.I.; Khein, L.A.; Korotkova, N.A.; Korzhavina, I.A.; Kuzmin, V.A.; Lukina, O.Yu.; Proskuryakov, A.S.; Shcheglova, L.M.; Solomin, A.N.; Vlasov, N.N.; Zotkin, S.A.; Bokel, C.; Botje, M.; Bruemmer, N.; Engelen, J.; Grijpink, S.; Koffeman, E.; Kooijman, P.; Schagen, S.; van Sighem, A.; Tassi, E.; Tiecke, H.; Tuning, N.; Velthuis, J.J.; Vossebeld, J.; Wiggers, L.; de Wolf, E.; Bylsma, B.; Durkin, L.S.; Gilmore, J.; Ginsburg, C.M.; Kim, C.L.; Ling, T.Y.; Boogert, S.; Cooper-Sarkar, A.M.; Devenish, R.C.E.; Grosse-Knetter, J.; Matsushita, T.; Ruske, O.; Sutton, M.R.; Walczak, R.; Bertolin, A.; Brugnera, R.; Carlin, R.; Dal Corso, F.; Dusini, S.; Limentani, S.; Longhin, A.; Posocco, M.; Stanco, L.; Turcato, M.; Adamczyk, L.; Iannotti, L.; Oh, B.Y.; Okrasinski, J.R.; Saull, P.R.B.; Toothacker, W.S.; Whitmore, J.J.; Iga, Y.; D'Agostini, G.; Marini, G.; Nigro, A.; Cormack, C.; Hart, J.C.; McCubbin, N.A.; Shah, T.P.; Epperson, D.; Heusch, C.; Sadrozinski, H.F.-W.; Seiden, A.; Wichmann, R.; Williams, D.C.; Park, I.H.; Pavel, N.; Abramowicz , H.; Dagan, S.; Kananov, S.; Kreisel, A.; Levy, A.; Abe, T.; Fusayasu, T.; Kohno, T.; Umemori, K.; Yamashita, T.; Hamatsu, R.; Hirose, T.; Inuzuka, M.; Kitamura, S.; Matsuzawa, K.; Nishimura, T.; Arneodo, M.; Cartiglia, N.; Cirio, R.; Costa, M.; Ferrero, M.I.; Maselli, S.; Monaco, V.; Peroni, C.; Ruspa, M.; Sacchi, R.; Solano, A.; Staiano, A.; Bailey, D.C.; Fagerstroem, C.-P.; Galea, R.; Koop, T.; Levman, G.M.; Martin, J.F.; Mirea, A.; Sabetfakhri, A.; Butterworth, J.M.; Hayes, M.E.; Heaphy, E.A.; Jones, T.W.; Lane, J.B.; West, B.J.; Ciborowski, J.; Ciesielski, R.; Grzelak, G.; Nowak, R.J.; Pawlak, J.M.; Pawlak, R.; Smalska, B.; Tymieniecka, T.; Wroblewski, A.K.; Zakrzewski, J.A.; Zarnecki, A.F.; Adamus, M.; Gadaj, T.; Deppe, O.; Eisenberg, Y.; Hochman, D.; Karshon, U.; Badgett, W.F.; Chapin, D.; Cross, R.; Foudas, C.; Mattingly, S.; Reeder, D.D.; Smith, W.H.; Vaiciulis, A.; Wildschek, T.; Wodarczyk, M.; Deshpande, A.; Dhawan, S.; Hughes, V.W.; Bhadra, S.; Catterall, C.; Cole, J.E.; Frisken, W.R.; Hall-Wilton, R.; Khakzad, M.; Menary, S.
2001-01-01
Differential cross sections for dijet photoproduction in association with a leading neutron using the reaction e + +p→e + +n+jet+jet+X r have been measured with the ZEUS detector at HERA using an integrated luminosity of 6.4 pb -1 . The fraction of dijet events with a leading neutron in the final state was studied as a function of the jet kinematic variables. The cross sections were measured for jet transverse energies E T jet >6 GeV, neutron energy E n >400 GeV, and neutron production angle θ n <0.8 mrad. The data are broadly consistent with factorization of the lepton and hadron vertices and with a simple one-pion-exchange model
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.
Pion-transfer (n,d) and (d, 3He) reactions leading to deeply bound pionic atoms
International Nuclear Information System (INIS)
Toki, H.; Hirenzaki, S.; Yamazaki, T.
1990-11-01
Theoretical studies are given on the (n,d) and (d, 3 He) reactions leading to deeply bound pionic atoms in heavy nuclei of configuration [(nl) π ·j n -1 ]J. The cross sections for various pionic and neutron-hole configurations in the case of a 208 Pb target are calculated at incident energies 300-1000 MeV/u by using the effective number approach and the eikonal approximation for distortion. The effective number with a pion in the 1s or 2p state and a neutron hole in the i 13/2 orbit peaks around the same incident energy (T n =600 MeV) as the elementary cross section n+n→d+π - , where the momentum transfer matches the angular-momentum transfer of L=5∼7. The DWIA cross section for (n,d) producing a pion in the 1s or 2p orbit at T n =600 MeV is found to be around 42 or 75 μb/sr, respectively. At T n =350 MeV, where the momentum transfer is small, quasi-substitutional states of configurations [(2p) π (3p 1/2 ) n -1 ]L=0 and [(2p) π (3p 3/2 ) n -1 ]L=0 are preferentially populated with cross sections of 190 and 380 μb/sr, respectively. The (d, 3 He) cross sections are estimated to be an order of magnitude smaller than the (n,d) cross sections. Thus, the (n,d) and (d, 3 He) reactions are found to be suited for the production of deeply bound pionic atoms. (author)
Study of single pion production in antineutrino induced charged current interactions
International Nuclear Information System (INIS)
Bolognese, Teresa.
1978-01-01
Results are presented on the exclusive charged current antineutrino production of one pion using the data of the Gargamelle propane experiment at CERN PS. The isospin structure of the charged weak current is studied as well as the energy dependence of the total cross section for π - antineutrino production, which is compared with the prediction of Adler's model [fr
Remarks on the pion-nucleon σ-term
Hoferichter, Martin; Ruiz de Elvira, Jacobo; Kubis, Bastian; Meißner, Ulf-G.
2016-09-01
The pion-nucleon σ-term can be stringently constrained by the combination of analyticity, unitarity, and crossing symmetry with phenomenological information on the pion-nucleon scattering lengths. Recently, lattice calculations at the physical point have been reported that find lower values by about 3σ with respect to the phenomenological determination. We point out that a lattice measurement of the pion-nucleon scattering lengths could help resolve the situation by testing the values extracted from spectroscopy measurements in pionic atoms.
Determination of the pion-nucleon coupling constant and scattering lengths
International Nuclear Information System (INIS)
Ericson, T.E.O.; Loiseau, B.; Thomas, A.W.
2002-01-01
We critically evaluate the isovector Goldberger-Miyazawa-Oehme (GMO) sum rule for forward πN scattering using the recent precision measurements of π - p and π - d 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, g c 2 (GMO)/4π=14.11±0.05(statistical)±0.19(systematic) or f c 2 /4π=0.0783(11). This value is intermediate between that of indirect methods and the direct determination from backward np differential scattering cross sections. We also use the pionic atom data to deduce the coherent symmetric and antisymmetric sums of the pion-proton and pion-neutron scattering lengths with high precision, namely, (a π - p +a π - n )/2=[-12±2(statistical)±8(systematic)]x10 -4 m π -1 and (a π - p -a π - n )/2=[895±3(statistical)±13 (systematic)]x10 -4 m π -1 . For the need of the present analysis, we improve the theoretical description of the pion-deuteron scattering length
How Many Muons Do We Need to Store in a Ring For Neutrino Cross-Section Measurements?
International Nuclear Information System (INIS)
Geer, Steve
2011-01-01
Analytical estimate of the number of muons that must decay in the straight section of a storage ring to produce a neutrino and anti-neutrino beam of sufficient intensity to facilitate cross-section measurements with a statistical precision of 1%. As we move into the era of precision long-baseline ν μ → ν e and (bar ν) μ → (bar ν) e measurements there is a growing need to precisely determine the ν e and (bar ν) e cross-sections in the relevant energy range, from a fraction of 1 GeV to a few GeV. This will require ν e and (bar ν) e beams with precisely known fluxes and spectra. One way to produce these beams is to use a storage ring with long straight sections in which muon decays (μ - → e - ν μ (bar ν) e if negative muons are stored, and ν + → e + ν e (bar ν) μ if positive muons are stored) produce the desired beam. The challenge is to capture enough muons in the ring to obtain useful neutrino and anti-neutrino fluxes. Early proposals to use a muon storage ring for neutrino oscillation experiments were based upon injecting 'high energy' charged pions into the ring which then decayed to create stored muons. These proposals were hampered by lack of sufficient intensity to pursue the physics. The Neutrino Factory proposal in 1997 was designed to fix this problem by using a Muon Collider class 'low energy' muon source to capture many more pions at low energy, allow them to decay in an external decay channel, manipulate their phase space to capture as many muons as possible within the acceptance of an accelerator, and then accelerate to the energy of choice before injecting into a specially designed ring with long straight sections. All this technology would do a wonderful job in fixing the intensity problem, but at a price that excludes this solution from being realized in the short term. The question that we are now faced with is whether the older, lower intensity 'parasitic' muon storage ring based on 'high energy' pion decays can, with
Pion production in 3He collisions on complex nuclei: a comparison of theory with experiment
International Nuclear Information System (INIS)
Fulcher, L.P.; Banerjee, M.K.
1976-01-01
The BLSZ theory of inclusive pion production is applied to the (p,π + ) and the ( 3 He,π 0 ) reactions on 12 C. The calculations are based on plane waves for the projectile and pion wave functions and are compared with experiments. The effects of distortion are considered. The magnitudes of the (p,π + ) reaction cross sections are comparable to the experimental values, but for the ( 3 He,π 0 ) case the theoretical results are four or five orders of magnitude larger than the experiments
DWPI: a computer program to calculate the inelastic scattering of pions from nuclei
Energy Technology Data Exchange (ETDEWEB)
Eisenstein, R A; Miller, G A [Carnegie-Mellon Univ., Pittsburgh, Pa. (USA). Dept. of Physics
1976-02-01
Angular distributions for the inelastic scattering of pions are generated using the distorted wave impulse approximation (DWIA). The cross section for a given transition is calculated by summing a partial wave expansion. The T-matrix elements are calculated using distorted pion waves from the program PIRK, and therefore include elastic scattering to all orders. The excitation is treated in first order only. Several optical potentials and nuclear densities are available in the program. The transition form factor may be uncoupled from the ground-state density. Coulomb excitation, which interferes coherently with the strong interaction, is a program option.
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
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
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)
Sadler, M.E.; Isenhower, L.D.
1990-01-01
The LAMPF experiments have been performed in collaboration with UCLA, George Washington University, various groups at Los Alamos, and Catholic University. This paper discusses: a complete set of observables in the pion-nucleon system in the momentum interval 400-700 MeV/c; differential cross sections at low energy for pion-nucleon charge exchange; and elastic and inelastic scattering of π ± on 3 H and 3 He
Measurement of dijet cross sections for events with a leading neutron in photoproduction at HERA
Energy Technology Data Exchange (ETDEWEB)
Breitweg, J.; Chekanov, S.; Derrick, M.; Krakauer, D.; Magill, S.; Musgrave, B.; Pellegrino, A.; Repond, J.; Stanek, R.; Yoshida, R.; Mattingly, M.C.K.; Antonioli, P.; Bari, G.; Basile, M.; Bellagamba, L.; Boscherini, D.; Bruni, A.; Bruni, G.; Cara Romeo, G.; Cifarelli, L.; Cindolo, F.; Contin, A.; Corradi, M.; De Pasquale, S.; Giusti, P.; Iacobucci, G.; Levi, G.; Margotti, A.; Massam, T.; Nania, R.; Palmonari, F.; Pesci, A.; Sartorelli, G.; Zichichi, A.; Amelung, C.; Bornheim, A.; Brock, I.; Coboeken, K.; Crittenden, J.; Deffner, R.; Hartmann, H.; Heinloth, K.; Hilger, E.; Irrgang, P.; Jakob, H.-P.; Kappes, A.; Katz, U.F.; Kerger, R.; Paul, E.; Rautenberg, J.; Schnurbusch, H.; Stifutkin, A.; Tandler, J.; Voss, K.C.; Weber, A.; Wieber, H.; Bailey, D.S.; Barret, O.; Brook, N.H.; Foster, B. E-mail: b.foster@bristol.ac.uk; Heath, G.P.; Heath, H.F.; Rodrigues, E.; Scott, J.; Tapper, R.J.; Capua, M.; Schioppa, M.; Susinno, G.; Jeoung, H.Y.; Kim, J.Y.; Lee, J.H.; Lim, I.T.; Ma, K.J.; Pac, M.Y.; Caldwell, A.; Liu, W.; Liu, X.; Mellado, B.; Paganis, S.; Sampson, S.; Schmidke, W.B.; Sciulli, F.; Chwastowski, J.; Eskreys, A.; Figiel, J.; Klimek, K.; Olkiewicz, K.; Piotrzkowski, K.; Przybycien, M.B.; Stopa, P.; Zawiejski, L.; Bednarek, B.; Jelen, K.; Kisielewska, D.; Kowal, A.M.; Kowalski, T.; Przybycien, M.; Rulikowska-Zarebska, E.; Suszycki, L.; Szuba, D.; Kotanski, A.; Bauerdick, L.A.T.; Behrens, U.; Bienlein, J.K.; Borras, K.; Chiochia, V.; Dannheim, D.; Desler, K.; Drews, G.; Fox-Murphy, A.; Fricke, U.; Goebel, F.; Goers, S.; Goettlicher, P.; Graciani, R.; Haas, T.; Hain, W.; Hartner, G.F.; Hebbel, K.; Hillert, S.; Koch, W.; Koetz, U.; Kowalski, H.; Labes, H.; Loehr, B.; Mankel, R.; Martens, J.; Martinez, M.; Milite, M.; Moritz, M.; Notz, D.; Petrucci, M.C.; Polini, A.; Rohde, M.; Savin, A.A.; Schneekloth, U.; Selonke, F.; Sievers, M.; Stonjek, S.; Wolf, G.; Wollmer, U.; Youngman, C.; Zeuner, W.; Coldewey, C.; Lopez-Duran Viani, A.; Meyer, A.; Schlenstedt, S.[and others
2001-02-26
Differential cross sections for dijet photoproduction in association with a leading neutron using the reaction e{sup +}+p{yields}e{sup +}+n+jet+jet+X{sub r} have been measured with the ZEUS detector at HERA using an integrated luminosity of 6.4 pb{sup -1}. The fraction of dijet events with a leading neutron in the final state was studied as a function of the jet kinematic variables. The cross sections were measured for jet transverse energies E{sub T}{sup jet}>6 GeV, neutron energy E{sub n}>400 GeV, and neutron production angle {theta}{sub n}<0.8 mrad. The data are broadly consistent with factorization of the lepton and hadron vertices and with a simple one-pion-exchange model.
International Nuclear Information System (INIS)
Amann, J.F.; Macek, R.J.; Sanford, T.W.L.
1982-10-01
We report here on a measurement of the 0 0 -production cross sections for low-energy negative secondaries from 10-, 18-, and 24-GeV protons on a variety of targets. Special emphasis is given to determining the dependence of the cross sections on incident proton energy
Isovector resonances in pion charge exchange
International Nuclear Information System (INIS)
Bowman, J.D.
1985-01-01
The (π ± , π 0 ) reactions as probes of isovector resonances are discussed. Experimental observation of the isovector monopole resonance is reported. Experimental results are presented for L=0, 1, and 2 isovector resonances and are compared to random-phase approximation calculations. In the experiments 40 Ca, 60 Ni, 90 Zr, 120 Sn, 140 Ce, and 208 Pb, targets were bombarded with 165 MeV π ± beams. Neutral pions were detected and double differential cross sections were determined for angles between 0 and 33deg and for π 0 energies between 90, 180, and 230 MeV. (Auth.)
Pions in nuclei, from virtual-pion exchange to real-pion transfer
International Nuclear Information System (INIS)
Yamazaki, Toshimitsu.
1988-07-01
Tracing the work of Miyazawa on nuclear magnetic moments, we discuss possible experimental ways to see whether a real pion exists in nuclei or not. While virtual pions are known to play an important role in nuclei, as clarified experimentally from anomalous orbital g factors of nucleons in nuclei, nearly nothing is known for the behavior of real pions in nuclei. We have shown that deeply bound hybrid states of π - are expected to exist in heavy nuclei, which can be populated by ''pion transfer'' reactions. (author)
International Nuclear Information System (INIS)
Schopper, H.; Moorhead, W.G.; Morrison, D.R.O.
1988-01-01
The aim of this report is to present a compilation of cross-sections (i.e. reaction rates) of elementary particles at high energy. The data are presented in the form of tables, plots and some fits, which should be easy for the reader to use and may enable him to estimate cross-sections for presently unmeasured energies. We have analyzed all the data published in the major Journals and Reviews for momenta of the incoming particles larger than ≅ 50 MeV/c, since the early days of elementary particle physics and, for each reaction, we have selected the best cross-section data available. We have restricted our attention to integrated cross-sections, such as total cross-sections, exclusive and inclusive cross-sections etc., at various incident beam energies. We have disregarded data affected by geometrical and/or kinematical cuts which would make them not directly comparable to other data at different energies. Also, in the case of exclusive reactions, we have left out data where not all of the particles in the final state were unambiguously identified. This work contains reactions induced by neutrinos, gammas, charged pions, kaons, nucleons, antinucleons and hyperons. (orig./HSI)
International Nuclear Information System (INIS)
Blomgren, J.; Olsson, N.; Rahm, J.
2000-01-01
The world data base on np scattering differential cross section data from 100 to 1000 MeV incident neutron energy has been reviewed. In addition, the status of the np total cross section and the pp → dπ + total cross section is discussed, as these have frequently been used to normalize np scattering data. It appears that the shapes of the largest np data sets tend to fall into two groups, with different steepness at backward angles. Also, it seems as the two major techniques for normalizing data yield incompatible results. Both these effects have consequences when using np data to determine the pion-nucleon coupling constant, g 2 πNN , which is currently under debate. (orig.)
International Nuclear Information System (INIS)
Cassing, W.
1984-12-01
The role of the time-dependent mean field in subthreshold pion production by first chance nucleon-nucleon collisions is studied for heavy-ion reactions at intermediate energies in a finite two-center shell model. It is found that the energy distribution of the nucleons for overlapping ions can roughly be approximated by shifted groundstate momentum distributions using a quasi-free dispersion relation. The absolute cross sections for the production of neutron pions can be reproduced from 35 MeV/u to 150 MeV/u. (orig.)
International Nuclear Information System (INIS)
Wittman, R.
1986-07-01
An impulse amplitude for pion photoproduction, suitable for the nuclear problem, is constructed with improved background dynamics and unitarity. The superior features of the amplitude are demonstrated at energies between threshold (E/sub γ/ = 150 MeV) and the Δ(1232) resonance energy (E/sub γ/ = 320 MeV) by discussing their effects on partial cross sections relevant to exclusive transitions in the 1p-shell. The specific reactions of 13 C(γ,π - ) 13 N/sub g.s./ and 14 N(γ,π + ) 14 C/sub g.s./ are discussed in light of these more general partial cross sections. The nuclear structure of the A = 14 system helps to enhance the effects considered. At or near resonance, very sizable (20 to 30%) effects arise both from the unitarity and from the refined treatment of the pionic final state interaction generated in the Δ-hole approach. Other examples of charged pion photoproduction reactions for 1p-shell nuclei are discussed briefly. Future theoretical improvements and experimental possibilities are suggested. 61 refs., 58 figs
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
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
Study of the baryon-baryon interaction in nucleon-nucleon and pion-deuteron scattering
International Nuclear Information System (INIS)
Fuchs, M.
1993-01-01
After the definition of the Hamiltonian in general form by meson production and absorption the transition to operators pursued, which connect only spaces with definite meson numbers. In this approximation first the self-energy of a single baryon was calculated in its full energy and momentum dependence. Then the formal expressions for the T matrices of nucleon-nucleon and pion-deuteron scattering were derived. The essential components of these expressions are the baryon-baryon T matrix ant transition amplitudes from pion-deuteron channels to baryon-baryon states. The central chapter dealt with the calculation of the baryon-baryon interaction for the general form of the vertices, with the solution of the binding problem and the baryon-baryon T matrix. Finally followed the results on the nucleon-nucleon and pion-deuteron scattering. For this first the transition amplitudes from pion-deuteron states to intermediate baryon-baryon states and the Born graphs of the pion-deuteron scattering had to be calculated. After some remarks to the transition from partial-wave decomposed T matrices to scattering observables an extensive representation of the total, partial, and differential cross sections and a series of spin observables (analyzing powers and spin correlations) for the elastic proton-proton, neutron-proton, and pion-deuteron scattering as well for the fusion reaction pp→πd and the breakup reaction πd→pp follows. Thereby the energies reached from the nucleon-nucleon respectively pion-deuteron threshold up to 100 MeV above the delta resonance
Phi meson production in pion proton interaction
International Nuclear Information System (INIS)
Makdisi, Y.I.
1976-01-01
The production of the phi meson and its decay mode into K + K - was investigated in a π - p → phi n reaction using a double arm effective mass spectrometer. Multiwire proportional chambers were deployed as particle detectors and a magnet provided momentum identification. Total cross sections were measured to be 18.5 +- 6, 24.1 +- 7, 25.1 +- 8.2 and 21.3 +- 7 μb for pion beam momenta of 1.6, 1.7, 1.8, and 2.0 GeV√c respectively and an upper limit of 15 μb was set for the 2.2 GeV/c point. These results coupled with other experiments done at higher energies show a strong energy dependence for this production process. Differential cross sections dsigma/dΩ were measured and cos THETA distributions in the center of mass system were consistent with isotropic production implying a flat differential cross section with respect to t. Although the statistics were quite an improvement on previous data they did not permit a thorough investigation of the decay density matrix elements. However, decay angular distributions in the Gottfried-Jackson frame were also presented
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
Application of a Regge model to the photoproduction of pion pairs
Energy Technology Data Exchange (ETDEWEB)
Bolz, Arthur; Sauter, Michel; Schoening, Andre [Physikalisches Institut, Universitaet Heidelberg, Im Neuenheimer Feld 226, D-69120 Heidelberg (Germany); Ewerz, Carlo [Institut fuer Theoretische Physik, Universitaet Heidelberg, Philosophenweg 16, D-69120 Heidelberg (Germany); ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum fuer Schwerionenforschung, Planckstrasse 1, D-64291 Darmstadt (Germany); Maniatis, Markos [Departamento de Ciencias Basicas, Universidad del Bio-Bio, Avda. Andres Bello s/n, Casilla 447, Chillan 3780000 (Chile); Nachtmann, Otto [Institut fuer Theoretische Physik, Universitaet Heidelberg, Philosophenweg 16, D-69120 Heidelberg (Germany)
2015-07-01
In a recent publication (arXiv:1409.8483) a model in the spirit of Regge theory is used to describe the reaction γp → π{sup +}π{sup -} p at high energies. Both resonant pion-pion production via the meson resonances ρ(770), ω(782), ρ(1450) and f{sub 2}(1270) as well as non-resonant amplitudes are considered. Photon and proton interact by the exchange of the photon, the pomeron and reggeons as well as by a yet unobserved but possible odderon. Cross sections calculated from this model and their dependencies on various kinematic quantities are discussed and compared to experimental data. The focus is on angular distributions which feature asymmetries that could be used for an odderon discovery.
A new version of PIRK (elastic pion-nucleus scattering) to handle differing proton and neutron radii
International Nuclear Information System (INIS)
Funsten, H.O.
1979-01-01
This program is a modification of the Eisenstein-Miller program (1974) for calculating elastic pion-nucleus differential cross sections using free π-N scattering amplitudes. This revision permits the use of separate proton and neutron radii for the nuclear density function rho(r). (Auth.)
International Nuclear Information System (INIS)
Karimaeki, V.
1975-01-01
The energy behaviour of total cross sections of exclusive channel with one, two or three produced pions has been studied in pp and πp interactions. Two components, interpreted as diffractive and non-diffractive, have been fitted to the cross section data assuming an asymptotic power law dependence in psub(lab) for both. Isotopic spin factors were used as constraints to fit different charge channels simultaneously as well as for determining diffractive cross sections for non-observable few-body channels. The diffractive component for fixed multiplicity is found to decrease as psub(lab)sup(-0.16+-0.04). Results are compared with the predictions of factorization and semilocal factorization hypotheses. Total diffractive cross sections derived by the analysis are 5.1+-0.6 mb in pp and 2.2+-0.3 mb in πp interactions at psub(lab)=10 GeV/c. (author)
Pion-pair formation and the pion dispersion relation in a hot pion gas
Energy Technology Data Exchange (ETDEWEB)
Chanfay, G. [Lyon-1 Univ., 69 - Villeurbanne (France). Inst. de Physique Nucleaire; Alm, T. [Rostock Univ. (Germany); Schuck, P. [Grenoble-1 Univ., 38 (France). Inst. des Sciences Nucleaires; Welke, G. [Wayne State Univ., Detroit, MI (United States). Dept. of Physics and Astronomy
1996-09-01
The possibility of pion-pair formation in a hot pion gas, based on the bosonic gap equation, is pointed out and discussed in detail. The critical temperature for condensation of pion pairs (Evans-Rashind transition) is determined as a function of the pion density. As for fermions, this phase transition is signaled by the appearance of a pole in the two-particle propagator. In Bose systems there exists a second, lower critical temperature, associated with the appearance of the single-particle condensate. Between the two critical temperatures the pion dispersion relation changes from the usual quasiparticle dispersion to a Bogoliubov-like dispersion relation at low momenta. This generalizes the non-relativistic results for an attractive Bose gas by Evans et al. Possible consequences for the inclusive pion spectra measured in heavy-ion collisions at ultra-relativistic energies are discussed. 21 refs.
Inelastic pion scattering by 13C at low energies
International Nuclear Information System (INIS)
Mitchell, J.H.
1987-03-01
Angular distributions for inelastically scattered pions were obtained for several states in 13 C at an incident energy of 65 MeV. The data include results from both π + and π - measurements. In addition, π - measurements were made at T/sub π/ = 50 MeV at one angle to give a two point fixed-q excitation function. The data are compared to theory and the data of others. As might be expected, medium corrections are shown to be considerably more important at low energies than at resonance. This is true for inelastic transitions of multipolarity 0,2 and 3. Parameters derived from an analysis of elastic pion scattering and SCX data also provide an adequate description of the inelastic transitions. The charge asymmetry in the cross sections for the 9/2 + state that was seen at resonance persists at these energies. This result is consistent with an impulse approximation treatment of the spin-flip amplitude. This is true even though the incoming energy of the pions is far below the range where the validity of an impulse treatment is expected. 65 refs., 45 figs
International Nuclear Information System (INIS)
Sadler, M.E.
1989-01-01
This report describes the pion scattering programs in which Abilene Christian University collaborated under this contract which ended May 14, 1988. The experiments were conducted at the Clinton P. Anderson Meson Physics Facility at Los Alamos (LAMPF). The experiments were performed in collaboration with UCLA, George Washington University, LAMPF Groups MP-4, MP-10 and MP-13, and Catholic University. The measurements included: (1) a complete set of observables in the pion-nucleon system in the momentum interval 400--700 MeV/c, (2) differential cross sections at low energy for pion-nucleon charge exchange, and (3) elastic and inelastic scattering of π ± on 3 H and 3 He
High resolution studies of pion-nucleus reaction mechanism
International Nuclear Information System (INIS)
Morris, C.L.
1983-01-01
Pion inelastic scattering is generally well described as a first order process using the DWIA. This is especially true for a large body of inelastic scattering data to low-lying collective states which is well-described by form factors obtained in (e,e') and the DWIA. Some data for which this model does not work are presented. Higher order reaction mechanisms have been invoked to explain some of these data. However, no model of these second order processes gives a satisfactory explanation of the entire data set. Experimentally, more data for pion-induced transitions to low-spin unnatural-parity states which have been studied by other probes would be useful in sorting out the reaction mechanisms responsible for the anomalous cross sections observed for the 1 + states in 12 C. Theoretically, a consistent evaluation of possible second-order diagrams in inelastic scattering, such as is being attempted for DCX 22 , would be useful
Dispersive analysis of the pion transition form factor
Energy Technology Data Exchange (ETDEWEB)
Hoferichter, M. [Technische Universitaet Darmstadt, Institut fuer Kernphysik, Darmstadt (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, ExtreMe Matter Institute EMMI, Darmstadt (Germany); University of Bern, Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics, Bern (Switzerland); Kubis, B.; Niecknig, F.; Schneider, S.P. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Bonn (Germany); Leupold, S. [Uppsala Universitet, Institutionen foer fysik och astronomi, Box 516, Uppsala (Sweden)
2014-11-15
We analyze the pion transition form factor using dispersion theory. We calculate the singly-virtual form factor in the time-like region based on data for the e{sup +}e{sup -} → 3π cross section, generalizing previous studies on ω, φ → 3π decays and γπ → ππ scattering, and verify our result by comparing to e{sup +}e{sup -} → π{sup 0}γ data. We perform the analytic continuation to the space-like region, predicting the poorlyconstrained space-like transition form factor below 1 GeV, and extract the slope of the form factor at vanishing momentum transfer a{sub π} = (30.7 ± 0.6) x 10{sup -3}. We derive the dispersive formalism necessary for the extension of these results to the doubly-virtual case, as required for the pion-pole contribution to hadronic light-by-light scattering in the anomalous magnetic moment of the muon. (orig.)
Willocq, S.; Aderholz, M.; Akbari, H.; Allport, P. P.; Badyal, S. K.; Ballagh, H. C.; Barth, M.; Bingham, H. H.; Brucker, E. B.; Burnstein, R. A.; Cence, R. J.; Chatterjee, T. K.; Clayton, E. F.; Corrigan, G.; de Prospo, D.; Devanand; de Wolf, E.; Faulkner, P. J.; Foeth, H.; Fretter, W. B.; Gupta, V. K.; Hanlon, J.; Harigel, G.; Harris, F. A.; Jacques, P.; Jain, V.; Jones, G. T.; Jones, M. D.; Kafka, T.; Kalelkar, M.; Kohli, J. M.; Koller, E. L.; Krawiec, R. J.; Lauko, M.; Lys, J. E.; Marage, P.; Milburn, R. H.; Mittra, I. S.; Mobayyen, M. M.; Moreels, J.; Morrison, D. R.; Myatt, G.; Nailor, P.; Naon, R.; Napier, A.; Passmore, D.; Peters, M. W.; Peterson, V. Z.; Plano, R.; Rao, N. K.; Rubin, H. A.; Sacton, J.; Sambyal, S. S.; Schmitz, N.; Schneps, J.; Singh, J. B.; Singh, S.; Smart, W.; Stamer, P.; Varvell, K. E.; Verluyten, L.; Wachsmuth, H.; Wainstein, S.; Yost, G. P.
1993-04-01
The coherent production of π and ρ mesons in νμ(ν¯μ)-neon charged-current interactions has been studied using the Fermilab 15-foot bubble chamber filled with a heavy Ne-H2 mix and exposed to the Teva- tron quadrupole triplet (anti)neutrino beam. The νμ (ν¯μ) beam had an average energy of 80 GeV (70 GeV). From a sample corresponding to approximately 28 000 charged-current interactions, net signals of (53+/-9) μ+/-π-/+ coherent events and (19+/-7) μ+/-π-/+π0 coherent events are extracted. For E>10 GeV, the coherent pion production cross section is determined to be (3.2+/-0.7)×10-38 cm2 per neon nucleus whereas the coherent ρ production cross section is (2.1+/-0.8)×10-38 cm2 per neon nucleus. These cross sections and the kinematical characteristics of the coherent events at ||t||<0.1 GeV2 are found to be in general agreement with the predictions of a model based on the hadron dominance and, in the pion case, on the partially conserved axial-vector current hypothesis. Also discussed is the coherent production of systems consisting of three pions.
Transverse momentum dependence of semi-inclusive pion production
International Nuclear Information System (INIS)
Hamlet Mkrtchyan; Peter Bosted
2007-01-01
Cross sections for semi-inclusive electroproduction of charged pions π ± from both proton and deuteron targets were measured for 0.2 2 2 , 0.3 t 2 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
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
International Nuclear Information System (INIS)
Sadler, M.E.
1986-03-01
Progress is reported for the past year in pion scattering programs. The measurements include: (1) a complete set of observables in the pion-nucleon system in the momentum interval 400 to 700 MeV/c, (2) differential cross sections at low energy for pion-nucleon charge exchange, and (3) elastic and inelastic scattering of π +- on 3 H and 3 He. The experiments are conducted at the Clinton P. Anderson Meson Physics Facility at Los Alamos (LAMPF)
An application of the Dipole Pomeron model to the pion-proton elastic scattering
International Nuclear Information System (INIS)
Covolan, R.J.M.; Leite, E.E.; Montanha, J.; Soares, M.S.
1994-01-01
The Pomeron model is applied to the pion-proton elastic scattering aiming to describe the total and differential cross sections and the ρ ratio between the scattering amplitude real and imaginary parts. It is also discussed how far the present available experimental results lead to the necessity of adopting a (α 0 > 1) supercritical trajectory. (author). 3 refs., 4 figs
Pions and neutrinos as probes of the nucleon and nuclear few-body system
International Nuclear Information System (INIS)
Hoffman, C.M.
1993-01-01
A number of studies of few-body nucleon and nuclear systems are being pursued at LAMPF using pions and neutrinos as probes. These include: a high-statistics measurement of the cross section for the reaction π + p → π + π o π 0 to determine the 1 = 2 ππ scattering length; precision measurements of the π - p charge exchange cross section in the region of the A; measurements of the cross section for the (π + p → π + π + p), from D, 3 He as 4 He as tests of charge symmetry and reaction mechanisms; measurements of the π + p cross section below the Δ; and studies of vp elastic scattering at low Q 2 to determine the quark content of the proton spin. Some of these experiments acquired data last year, while others are presently running. LAMPF, the highest power proton accelerator in the world, is presently in the midst of its 1993 production run
International Nuclear Information System (INIS)
Perkasa, Y. S.; Waris, A.; Kurniadi, R.; Su'ud, Z.
2014-01-01
Comparative studies of actinide and sub-actinide fission cross section calculation from MCNP6 and TALYS have been conducted. In this work, fission cross section resulted from MCNP6 prediction will be compared with result from TALYS calculation. MCNP6 with its event generator CEM03.03 and LAQGSM03.03 have been validated and verified for several intermediate and heavy nuclides fission reaction data and also has a good agreement with experimental data for fission reaction that induced by photons, pions, and nucleons at energy from several ten of MeV to about 1 TeV. The calculation that induced within TALYS will be focused mainly to several hundred MeV for actinide and sub-actinide nuclides and will be compared with MCNP6 code and several experimental data from other evaluator
The expanding pion liquid and the pion spectra
International Nuclear Information System (INIS)
Ayala, A.
1999-01-01
We compute the pion inclusive momentum distribution in heavy-ion collisions for energies at the Alternating Gradient Synchrotron (AGS), assuming thermal equilibrium and accounting for density and expansion effects at freeze out. We compare to data on mid-rapidity charged pions produced in central Au + Au collisions and find a very good agreement. The shape of the distribution at low transverse mass is explained in part as an effect arising from the high mean pion density achieved in these reactions. The difference between the positive and negative pion distributions in the same region is attributed in part to the different average yields of each kind of charged pions. (Author)
Energy Technology Data Exchange (ETDEWEB)
Sibirtsev, A; Haidenbauer, J; Huang, F; Krewald, S; Meissner, U -G
2009-04-01
We present a systematic analysis of backward pion photoproduction for the reactions $ \\gamma$ p $ \\rightarrow$ $ \\pi^{0}_{}$ p and $ \\gamma$ p $ \\rightarrow$ $ \\pi^{+}_{}$ n . Regge phenomenology is applied at invariant collision energies above 3GeV in order to fix the reaction amplitude. A comparision with older data on $ \\pi^{0}_{}$ - and $ \\pi^{+}_{}$ -photoproduction at $ \\vartheta$ = 180° indicates that the high-energy limit as given by the Regge calculation could be reached possibly at energies of around $ \\sqrt{{s}}$ ≃ 3 GeV. In the energy region of $ \\sqrt{{s}}$ $ \\le$2.5 GeV, covered by the new measurements of $ \\gamma$ p $ \\rightarrow$ $ \\pi^{0}_{}$ p differential cross-sections at large angles at ELSA, JLab, and LEPS, we see no clear signal for a convergence towards the Regge results. The baryon trajectories obtained in our analysis are in good agreement with those given by the spectrum of excited baryons.
Mechanisms for pion production in heavy ion collisions
International Nuclear Information System (INIS)
Pfeiffer, M.
1991-01-01
In the following contribution some aspects concerning pion production in heavy ion collisions will be discussed. After a general introduction the properties of pions and the Δ-resonance will be briefly mentioned. In the following section some points refering to the pion production in a relativistic heavy ion collision will be discussed. In addition, the basic ideas of the applied models will be shown. In the last part results from existing experiments and possible interpretations will be presented. (orig.)
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
Experimental studies of nucleon-nucleon and pion-nucleus interactions at intermediate energies
International Nuclear Information System (INIS)
1990-01-01
This report summarizes the work on experimental research in intermediate energy nuclear and particle physics carried out by New Mexico State University in 1988--91. Most of these studies have involved investigations of neutron-proton and pion-nucleus interactions. The neutron-proton research is part of a program of studies of interactions between polarized nucleons that we have been involved with for more than ten years. Its purpose has been to help complete the determination of the full set of ten complex nucleon-nucleon amplitudes at energies up to 800 MeV, as well as to continue investigating the possibility of the existence of dibaryon resonances. The give complex isospin-one amplitudes have been fairly well determined, partly as a result of this work. Our work in this period has involved measurements and analysis of data on elastic scattering and total cross sections for polarized neutrons on polarized protons. The pion-nucleus research continues our studies of this interaction in regions where it has not been well explored. One set of experiments includes studies of pion elastic and double-charge-exchange scattering at energies between 300 and 550 MeV, where our data is unique. Another involves elastic and single-charge-exchange scattering of pions from polarized nuclear targets, a new field of research which will give the first extensive set of information on spin-dependent pion-nucleus amplitudes. Still another involves the first set of detailed studies of the kinematic correlations among particles emitted following pion absorption in nuclei
Martini, M.; Chanfray, G.; Marteau, J.
2009-01-01
We present a theory of neutrino interactions with nuclei aimed at the description of the partial cross-sections, namely quasi-elastic and multi-nucleon emission, coherent and incoherent single pion production. For this purpose, we use the theory of nuclear responses treated in the random phase approximation, which allows a unified description of these channels. It is particularly suited for the coherent pion production where collective effects are important whereas they are moderate in the other channels. We also study the evolution of the neutrino cross-sections with the mass number from carbon to calcium. We compare our approach to the available neutrino experimental data on carbon. We put a particular emphasis on the multi-nucleon channel, which at present is not easily distinguishable from the quasi-elastic events. This component turns out to be quite relevant for the interpretation of experiments (K2K, MiniBooNE, SciBooNE). It can account in particular for the unexpected behavior of the quasi-elastic cro...
Pion photoproduction in the Skyrme model and low-energy theorem
International Nuclear Information System (INIS)
Saito, Sakae; Takeuchi, Fuminaka; Uehara, Masayuki
1993-01-01
We investigate pion photoproduction on the nucleon in the Skyrme model. We employ the formulation, which was recently developed by Hayashi et al., that the full pion field is treated as an interpolating field between asymptotic in and out fields. It is shown that the amplitude of the pion photoproduction is correctly given by the direct and the crossed baryon-pole terms, and the equal-time commutator terms between the axial-vector current and the electromagnetic current and between the pion field and the latter. We show that the lowest-order Kroll-Ruderman and the pion pole terms are reproduced, and that the seagull terms inherent to the Skyrme model are present. Further, the threshold behavior of the amplitude is discussed. (orig.)
Pion absorption on 4He into the ppd final state
International Nuclear Information System (INIS)
Planinic, M.; Androic, D.; Backenstoss, G.; Bosnar, D.; Dooling, T.; Furic, M.; Gram, P. A. M.; Gregory, N. K.; Hoffart, A.; Ingram, C. H. Q.
2000-01-01
Results from a 4π solid angle measurement of the reaction π + + 4 He→ppd at incident pion energies of T π + =70, 118, 162, 239, and 330 MeV are presented. Integrated cross sections are given for the final states with energetic deuterons (ppd) and (pd)p. The differential cross sections are described by a complete set of five independent variables and various other kinematic variables and compared to cascade and phase space models where deuterons were formed by a semiclassical pickup model. The data are investigated for signatures of initial and final state interactions: it is found that more than half of the (ppd) yield cannot be explained by these mechanisms. The remaining strength is reasonably well reproduced by 3N phase space models followed by pickup. (c) 2000 The American Physical Society
International Nuclear Information System (INIS)
Rana, Mukhtar Ahmed; Sher, Gul; Manzoor, Shahid; Shahzad, M. I.
2011-01-01
Fission cross-sections of 119 Sn and 209 Bi induced by negative pions of two energies 500 and 672 MeV were measured using a CR-39 nuclear track detector. Target-detector stacks were exposed to pion beams at the Brookhaven National Laboratory (USA). Measurement results are compared with the corresponding calculations using the computer code CEM95. Agreement between measurements and calculations is fairly good for the 209 Bi target nuclei whereas it is poor for 119 Sn at both investigated energies of 500 and 672 MeV. Fission cross-section results of 119 Sn and 209 Bi are explained using the equilibrium properties of these nuclides including nuclear electric quadrupole moments which determine the shapes of nuclei. A logarithmic dependence of fission cross-section on Z 2 /A is observed for the above-mentioned reactions and a critical limit of Z 2 /A is identified with the value of 30 which divides the curve of σ f versus Z 2 /A into two regimes, one with weak dependence and the other with strong dependence. (nuclear physics)
Mukhtar, Ahmed Rana; Gul, Sher; Shahid, Manzoor; I. Shahzad, M.
2011-09-01
Fission cross-sections of 119Sn and 209Bi induced by negative pions of two energies 500 and 672 MeV were measured using a CR-39 nuclear track detector. Target-detector stacks were exposed to pion beams at the Brookhaven National Laboratory (USA). Measurement results are compared with the corresponding calculations using the computer code CEM95. Agreement between measurements and calculations is fairly good for the 209Bi target nuclei whereas it is poor for 119Sn at both investigated energies of 500 and 672 MeV. Fission cross-section results of 119Sn and 209Bi are explained using the equilibrium properties of these nuclides including nuclear electric quadrupole moments which determine the shapes of nuclei. A logarithmic dependence of fission cross-section on Z2/A is observed for the above-mentioned reactions and a critical limit of Z2/A is identified with the value of 30 which divides the curve of σf versus Z2/A into two regimes, one with weak dependence and the other with strong dependence.
Measurement of the doubly differential cross section for π-p → π+π-n near threshold
International Nuclear Information System (INIS)
Walter, J.B.
1980-05-01
The doubly differential cross sections for the π + from the reaction π - p → π + π - n were measured at about twenty points for each of five energies between 245 MeV and 356 MeV. The experiment was carried out at the Clinton P. Anderson Meson Physics Facility, where a double focusing magnetic spectrometer detected the π + mesons produced in a liquid hydrogen target. The measurements were normalized by comparison with π - p elastic scattering measured with the same apparatus. These are the first such measurements in this energy range, and have an accuracy between 4.7% and 39%. The integrated reaction cross section was determined at each energy with an accuracy of about 5%. These agree with but are an improvement over previous measurements in this energy range. Comparison of the extrapolated threshold value of the mean square modulus of the matrix element with the soft pion calculations favors the symmetry breaking mechanism of Weinberg (xi = 0). It also demonstrates the futility of attempting to determine the symmetry breaking parameter xi from a single measurement of the integrated reaction cross section
Determination of the pion charge form factor for Q2 = 0.60-1.60 (GeV/c)2
International Nuclear Information System (INIS)
Vardan Tadevosyan; Henk Blok; Garth Huber; David Abbott; Heinz Anklin; Christopher Armstrong; John Arrington; Ketevi Assamagan; Steven Avery; O. Baker; C. Bochna; Edward Brash; Herbert Breuer; Nicholas Chant; James Dunne; T. Eden; Rolf Ent; David Gaskell; Ronald Gilman; Kenneth Gustafsson; Wendy Hinton; Harold Jackson; Mark Jones; Cynthia Keppel; Pyunghun Kim; Wooyoung Kim; Andreas Klein; Douglas Koltenuk; Meihua Liang; George Lolos; Allison Lung; David Mack; David McKee; David Meekins; Joseph Mitchell; Hamlet Mkrtchyan; Robert Mueller; Gabriel Niculescu; Maria-Ioana Niculescu; David Pitz; David Potterveld; Liming Qin; Joerg Reinhold; Ilkyoung Shin; Stepan Stepanyan; Liguang Tang; Rob van der Meer; Kelley Vansyoc; D. Van Westrum; Jochen Volmer; William Vulcan; Stephen Wood; Chen Yan; Wenxia Zhao; Benedikt Zihlmann
2006-01-01
The data analysis for the reaction H(e,e(prime) pi + )n, which was used to determine values for the charged pion form factor Fpi for values of Q2 = 0.6-1.6 (gEv/C) 2 , has been repeated with careful inspection of all steps and special attention to systematic uncertainties. Also the method used to extract Fpi from the measured longitudinal cross section was critically reconsidered. Final values for the separated longitudinal and transverse cross sections and the extracted values of Fpi are presented
Measurement of pion double charge exchange on carbon-13, carbon-14, magnesium-26, and iron-56
International Nuclear Information System (INIS)
Seidl, P.A.
1985-02-01
Cross sections for the /sup 13,14/C, 26 Mg, 56 Fe(π + ,π - )/sup 13,14/O, 26 Si, 56 Ni reactions were measured with the Energetic Pion Channel and Spectrometer at the Clinton P. Anderson Meson Physics Facility for 120 less than or equal to T/sub π/ less than or equal to 292 MeV and 0 less than or equal to theta less than or equal to 50. The double isobaric analog states (DIAS) are of primary interest. In addition, cross sections for transitions to 14 O(0 + , 5.92 MeV), 14 O(2 + , 7.77 MeV), 56 Ni(gs), 13 O(gs), and 13 O(4.21 MeV) are presented. The 13 O(4.21 MeV) state is postulated to have J/sup π/ = 1/2 - . The data are compared to previously measured double-charge-exchange cross sections on other nuclei, and the systematics of double charge exchange on T greater than or equal to 1 target nuclei leading to the DIAS are studied. Near the Δ 33 resonance, cross sections for the DIAS transitions are in disagreement with calculations in which the reaction is treated as sequential charge exchange through the free pion-nucleon amplitude, while for T/sub π/ > 200 MeV the anomalous features of the 164 MeV data are not apparent. This is evidence for significant higher order contributions to the double-charge-exchange amplitude near the reasonable energy. Two theoretical approaches that include two nucleon processes are applied to the DIAS data. 64 references
Czech Academy of Sciences Publication Activity Database
Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Alford, J.; Anson, C.; Aparin, A. A.; Arkhipkin, D.; Barnovská, Zuzana; Bielčík, J.; Bielčíková, Jana; Chaloupka, P.; Pachr, M.; Rusňák, Jan; Šumbera, Michal; Tlustý, David; Vértési, Robert
2014-01-01
Roč. 89, č. 1 (2014), 012001 ISSN 1550-7998 R&D Projects: GA ČR GA13-20841S Institutional support: RVO:61389005 Keywords : pions production * transverse momentum * STAR Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 4.643, year: 2014
Search for low mass exotic baryons in one pion electroproduction data measured at JLAB
International Nuclear Information System (INIS)
Tatischeff, B.; Tomasi-Gustafsson, E.
2007-02-01
This paper aims to give further evidence for the existence of low mass exotic baryons. Narrow structures in baryonic missing mass or baryonic invariant mass were previously observed during the last ten years. Since their existence is sometimes questionable, the structure functions of one pion electroproduction cross sections, measured at JLAB, are studied to add information on the possible existence of these narrow exotic baryonic resonances. (authors)
Energy Technology Data Exchange (ETDEWEB)
Fuchey, Eric [Blaise Pascal Univ., Aubiere (France)
2010-06-01
The past decade has seen a strong evolution of the study of the hadron structure through exclusive processes, allowing to access to a more complete description of this structure. Exclusive processes include DVCS (Deeply Virtual Compton Scattering) as well as hard exclusive meson production. This document is particularly focussed on the latter, and more particularly on exclusive neutral pion production. In this thesis is described the analysis of triple coincidence events H(e, e'γγ)X, which were a consequent by-product of the DVCS experiment which occured during Fall 2004 at Jefferson Lab Hall A, to extract the ep → epπ^{0} cross section. This cross section has been measured at two values of four-momentum transfer Q^{2} = 1.9 GeV^{2} and Q^{2} = 2.3 GeV^{2}. The statistical precision for these measurements is achieved at better than 5 %. The kinematic range allows to study the evolution of the extracted cross section as a function of Q^{2} and W. Results are be confronted with Regge inspired calculations and Generalized (GPD) predictions. An intepretation of our
Single neutral pion production by charged-current ν¯μ interactions on hydrocarbon at 〈Eν〉=3.6 GeV
Directory of Open Access Journals (Sweden)
T. Le
2015-10-01
Full Text Available Single neutral pion production via muon antineutrino charged-current interactions in plastic scintillator (CH is studied using the MINERvA detector exposed to the NuMI low-energy, wideband antineutrino beam at Fermilab. Measurement of this process constrains models of neutral pion production in nuclei, which is important because the neutral-current analog is a background for ν¯e appearance oscillation experiments. The differential cross sections for π0 momentum and production angle, for events with a single observed π0 and no charged pions, are presented and compared to model predictions. These results comprise the first measurement of the π0 kinematics for this process.
Inclusive production of charged pions in 200 GeV/c π-p interactions
International Nuclear Information System (INIS)
Fokitis, E.D.
1976-01-01
π - p interactions have been studied experimentally at 200 GeV/c. Topological cross sections and multiplicity moments of this reaction have been presented. These features have been compared with data from other experiments. The dependence of inclusive π/sup +-/ production cross sections on rapidity for this reaction are presented and compared with the data on pp collisions at the same energy. Some theoretical hypotheses, valid at asymptotically high energies, have been discussed in light of these high energy data. The production of positive and negative pions in single- and two-pion inclusive reactions has been studied in terms of current models of cluster production in high energy reactions. In single π - production, a strong leading particle effect is observed, which is associated with a significant production of leading clusters in high energy reactions. Two-particle inclusive reactions have been presented in terms of inclusive differential cross sections and correlations. Correlations of dynamic origin are found, when particles are in small rapidity separation. This is demonstrated by comparing the data with the expected correlations calculated from an independent particle emission model. The presence of these correlations supports the production of clusters in this energy range. The dependence of these correlations on energy and the type of colliding particles has been discussed using data on azimuthal correlations for two particles. These data have been compared with an independent cluster production model including Bose--Einstein statistics on the final state identical particles. This model reproduces the qualitative features observed in experiments, but cannot account for all the experimental features quantitatively
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
Basic considerations in simulated treatment planning for the Stanford Medical Pion Generator (SMPG)
International Nuclear Information System (INIS)
Pistenma, D.A.; Li, G.C.; Bagshaw, M.A.
1977-01-01
Recent interest in charged heavy particle irradiation is based upon expected improved local tumor control rates because of the greater precision in dose localization and the increased biological effectiveness of the high linear energy transfer ionization of particle beams in their stopping regions (Bragg peaks). A novel 60 beam cylindrical geometry pion spectrometer designed for a hospital-based pion therapy facility has been constructed at Stanford. In conjunction with the development and testing of the SMPG a program of simulated treatment planning is being conducted. This paper presents basic considerations in treatment planning for pions and other charged heavy particles. It also presents the status of simulated treatment planning calculations for the SMPG including a discussion of the principle of irradiation of hypothetical tumor volumes illustrated by examples of simplified treatment plans incorporating tissue density inhomogeneity corrections. Also presented are considerations for realistic simulated treatment planning calculations using computerized tomographic scan cross sections of actual patients and a conceptual plan for an integrated treatment planning and patient treatment system for the SMPG
International Nuclear Information System (INIS)
Lansberg, J. P.; Pire, B.; Szymanowski, L.
2007-01-01
We evaluate the cross section for pp→l + l - π 0 in the forward direction and for a large lepton pair invariant mass. In this kinematical region, the leading-twist amplitude factorizes into a short-distance matrix element, long-distance antiproton-distribution amplitudes, and proton to pion transition distribution amplitudes (TDAs). Using a modeling inspired from the chiral limit for these TDAs, we obtain a first estimate of this cross section, which demonstrates that this process can be measured at GSI-FAIR
Energy Technology Data Exchange (ETDEWEB)
Avakyan, R.O.; Avetisyan, A.; Bagdasaryan, A.S.; Vartapetyan, G.A.; Danagulyan, S.S.; Eganov, V.S.; Karapetyan, A.P.; Kosakov, I.K.; Marukyan, G.O.; Matevosyan, M.
1983-11-01
The energy dependence of the asymmetry in the cross section for the ..gamma..p..-->..p..pi../sup 0/ reaction induced by a polarized photon beam is measured in the energy region 0.75--1.3 GeV at the neutral-pion emission angle theta(0 = 70/sup 0/ in the c.m. system. The experimental data are compared with various theoretical predictions. A prediction based on the use of fixed-t dispersion relations is in satisfactory agreement with the experimental results.
From eV to EeV: Neutrino cross sections across energy scales
Energy Technology Data Exchange (ETDEWEB)
Formaggio, J. A.; Zeller, G. P.
2012-09-01
Since its original postulation by Wolfgang Pauli in 1930, the neutrino has played a prominent role in our understanding of nuclear and particle physics. In the intervening 80 years, scientists have detected and measured neutrinos from a variety of sources, both man-made and natural. Underlying all of these observations, and any inferences we may have made from them, is an understanding of how neutrinos interact with matter. Knowledge of neutrino interaction cross sections is an important and necessary ingredient in any neutrino measurement. With the advent of new precision experiments, the demands on our understanding of neutrino interactions is becoming even greater. The purpose of this article is to survey our current knowledge of neutrino cross sections across all known energy scales: from the very lowest energies to the highest that we hope to observe. The article covers a wide range of neutrino interactions including coherent scattering, neutrino capture, inverse beta decay, low energy nuclear interactions, quasi-elastic scattering, resonant pion production, kaon production, deep inelastic scattering and ultra-high energy interactions. Strong emphasis is placed on experimental data whenever such measurements are available.
Measurement of the e+e−→π+π− cross section between 600 and 900 MeV using initial state radiation
Directory of Open Access Journals (Sweden)
M. Ablikim
2016-02-01
Full Text Available We extract the e+e−→π+π− cross section in the energy range between 600 and 900 MeV, exploiting the method of initial state radiation. A data set with an integrated luminosity of 2.93 fb−1 taken at a center-of-mass energy of 3.773 GeV with the BESIII detector at the BEPCII collider is used. The cross section is measured with a systematic uncertainty of 0.9%. We extract the pion form factor |Fπ|2 as well as the contribution of the measured cross section to the leading-order hadronic vacuum polarization contribution to (g−2μ. We find this value to be aμππ,LO(600–900MeV=(368.2±2.5stat±3.3sys⋅10−10, which is between the corresponding values using the BaBar or KLOE data.
Lillich, Joachim
2003-01-01
For the first time at LEP the production of prompt photons is studied in the collisions of quasi-real photons using the OPAL data taken at e+e- centre-of mass energies between 183 GeV and 209 GeV. The total inclusive production cross-section for isolated prompt photons in the kinematic range of transverse momentum > 3.0 GeV and the absolut value of pseudorapidity <1 is determined to be (0.32 +- 0.04 (stat) +- 0.04 (sys)) pb. Differential cross-sections are compared to the predictions of a next-to-leading-order (NLO) calculation. In the second part of this thesis inclusive differential neutral pion cross-sections in photon photon collisons are measured. This measurement is an important test of QCD. In addition this process is the main background for prompt photons.
Quasifree pion electroproduction from nuclei in the Δ region
International Nuclear Information System (INIS)
Lee, F.X.; Wright, L.E.; Bennhold, C.
1995-10-01
We present calculations of the reaction Α (e, e 1 π N)B in the distorted wave impulse approximation. The reaction allows for the study of the production process in the nuclear medium without being obscured by the details of nuclear transition densities. First, a pion electroproduction operator suitable for nuclear calculations is obtained by extending the Blomqvist-Laget photoproduction operator to the virtual photon case. The operator is gauge invariant, unitary, reference frame independent, and describes the existing data reasonably well. Then it is applied in nuclei to predict nuclear cross sections under a variety of kinematic arrangements. Issues such as the effects of gauge-fixing, the interference of the Δ resonance with the background, sensitivities to be guadrupole component of the Δ excitation and to the electromagnetic form factors, the role of final-state interactions, are studied in detail. Methods on how to experimentally separate the various pieces in the coincidence cross section are suggested. Finally, the model is compared to recent SLAC experiment. (authors)
Patrick, C. E.; Aliaga, L.; Bashyal, A.; Bellantoni, L.; Bercellie, A.; Betancourt, M.; Bodek, A.; Bravar, A.; Budd, H.; Caceres v., G. F. R.; Carneiro, M. F.; Chavarria, E.; da Motta, H.; Dytman, S. A.; Díaz, G. A.; Felix, J.; Fields, L.; Fine, R.; Gago, A. M.; Galindo, R.; Gallagher, H.; Ghosh, A.; Gran, R.; Han, J. Y.; Harris, D. A.; Henry, S.; Hurtado, K.; Jena, D.; Kleykamp, J.; Kordosky, M.; Le, T.; Lu, X.-G.; Maher, E.; Manly, S.; Mann, W. A.; Marshall, C. M.; McFarland, K. S.; McGowan, A. M.; Messerly, B.; Miller, J.; Mislivec, A.; Morfín, J. G.; Mousseau, J.; Naples, D.; Nelson, J. K.; Norrick, A.; Nowak, G. M.; Nuruzzaman, Paolone, V.; Perdue, G. N.; Peters, E.; Ramírez, M. A.; Ransome, R. D.; Ray, H.; Ren, L.; Rodrigues, P. A.; Ruterbories, D.; Schellman, H.; Solano Salinas, C. J.; Sultana, M.; Sánchez Falero, S.; Teklu, A. M.; Valencia, E.; Wolcott, J.; Wospakrik, M.; Yaeggy, B.; Zhang, D.; Miner ν A Collaboration
2018-03-01
We present double-differential measurements of antineutrino charged-current quasielastic scattering in the MINERvA detector. This study improves on a previous single-differential measurement by using updated reconstruction algorithms and interaction models and provides a complete description of observed muon kinematics in the form of a double-differential cross section with respect to muon transverse and longitudinal momentum. We include in our signal definition zero-meson final states arising from multinucleon interactions and from resonant pion production followed by pion absorption in the primary nucleus. We find that model agreement is considerably improved by a model tuned to MINERvA inclusive neutrino scattering data that incorporates nuclear effects such as weak nuclear screening and two-particle, two-hole enhancements.
Adare, A.; Aidala, C.; Ajitanand, N. N.; Akiba, Y.; Akimoto, R.; Alexander, J.; Alfred, M.; Aoki, K.; Apadula, N.; Aramaki, Y.; Asano, H.; Atomssa, E. T.; Awes, T. C.; Azmoun, B.; Babintsev, V.; Bai, M.; Bai, X.; Bandara, N. S.; Bannier, B.; Barish, K. N.; Bathe, S.; Baublis, V.; Baumann, C.; Baumgart, S.; Bazilevsky, A.; Beaumier, M.; Beckman, S.; Belmont, R.; Berdnikov, A.; Berdnikov, Y.; Black, D.; Blau, D. S.; Bok, J. S.; Boyle, K.; Brooks, M. L.; Bryslawskyj, J.; Buesching, H.; Bumazhnov, V.; Butsyk, S.; Campbell, S.; Chen, C.-H.; Chi, C. Y.; Chiu, M.; Choi, I. J.; Choi, J. B.; Choi, S.; Christiansen, P.; Chujo, T.; Cianciolo, V.; Citron, Z.; Cole, B. A.; Cronin, N.; Crossette, N.; Csanád, M.; Csörgő, T.; Danley, T. W.; Datta, A.; Daugherity, M. S.; David, G.; Deblasio, K.; Dehmelt, K.; Denisov, A.; Deshpande, A.; Desmond, E. J.; Ding, L.; Dion, A.; Diss, P. B.; Do, J. H.; D'Orazio, L.; Drapier, O.; Drees, A.; Drees, K. A.; Durham, J. M.; Durum, A.; Engelmore, T.; Enokizono, A.; En'yo, H.; Esumi, S.; Eyser, K. O.; Fadem, B.; Feege, N.; Fields, D. E.; Finger, M.; Finger, M.; Fleuret, F.; Fokin, S. L.; Frantz, J. E.; Franz, A.; Frawley, A. D.; Fukao, Y.; Fusayasu, T.; Gainey, K.; Gal, C.; Gallus, P.; Garg, P.; Garishvili, A.; Garishvili, I.; Ge, H.; Giordano, F.; Glenn, A.; Gong, X.; Gonin, M.; Goto, Y.; Granier de Cassagnac, R.; Grau, N.; Greene, S. V.; Grosse Perdekamp, M.; Gu, Y.; Gunji, T.; Guragain, H.; Hachiya, T.; Haggerty, J. S.; Hahn, K. I.; Hamagaki, H.; Hamilton, H. F.; Han, S. Y.; Hanks, J.; Hasegawa, S.; Haseler, T. O. S.; Hashimoto, K.; Hayano, R.; He, X.; Hemmick, T. K.; Hester, T.; Hill, J. C.; Hollis, R. S.; Homma, K.; Hong, B.; Hoshino, T.; Hotvedt, N.; Huang, J.; Huang, S.; Ichihara, T.; Ikeda, Y.; Imai, K.; Imazu, Y.; Inaba, M.; Iordanova, A.; Isenhower, D.; Isinhue, A.; Ivanishchev, D.; Jacak, B. V.; Jeon, S. J.; Jezghani, M.; Jia, J.; Jiang, X.; Johnson, B. M.; Joo, E.; Joo, K. S.; Jouan, D.; Jumper, D. S.; Kamin, J.; Kanda, S.; Kang, B. H.; Kang, J. H.; Kang, J. S.; Kapustinsky, J.; Kawall, D.; Kazantsev, A. V.; Key, J. A.; Khachatryan, V.; Khandai, P. K.; Khanzadeev, A.; Kihara, K.; Kijima, K. M.; Kim, C.; Kim, D. H.; Kim, D. J.; Kim, E.-J.; Kim, G. W.; Kim, H.-J.; Kim, M.; Kim, Y.-J.; Kim, Y. K.; Kimelman, B.; Kistenev, E.; Kitamura, R.; Klatsky, J.; Kleinjan, D.; Kline, P.; Koblesky, T.; Kofarago, M.; Komkov, B.; Koster, J.; Kotchetkov, D.; Kotov, D.; Krizek, F.; Kurita, K.; Kurosawa, M.; Kwon, Y.; Lacey, R.; Lai, Y. S.; Lajoie, J. G.; Lebedev, A.; Lee, D. M.; Lee, G. H.; Lee, J.; Lee, K. B.; Lee, K. S.; Lee, S.; Lee, S. H.; Leitch, M. J.; Leitgab, M.; Lewis, B.; Li, X.; Lim, S. H.; Liu, M. X.; Lynch, D.; Maguire, C. F.; Makdisi, Y. I.; Makek, M.; Manion, A.; Manko, V. I.; Mannel, E.; Maruyama, T.; McCumber, M.; McGaughey, P. L.; McGlinchey, D.; McKinney, C.; Meles, A.; Mendoza, M.; Meredith, B.; Miake, Y.; Mibe, T.; Mignerey, A. C.; Miller, A. J.; Milov, A.; Mishra, D. K.; Mitchell, J. T.; Miyasaka, S.; Mizuno, S.; Mohanty, A. K.; Mohapatra, S.; Montuenga, P.; Moon, T.; Morrison, D. P.; Moskowitz, M.; Moukhanova, T. V.; Murakami, T.; Murata, J.; Mwai, A.; Nagae, T.; Nagamiya, S.; Nagashima, K.; Nagle, J. L.; Nagy, M. I.; Nakagawa, I.; Nakagomi, H.; Nakamiya, Y.; Nakamura, K. R.; Nakamura, T.; Nakano, K.; Nattrass, C.; Netrakanti, P. K.; Nihashi, M.; Niida, T.; Nishimura, S.; Nouicer, R.; Novák, T.; Novitzky, N.; Nyanin, A. S.; O'Brien, E.; Ogilvie, C. A.; Oide, H.; Okada, K.; Orjuela Koop, J. D.; Osborn, J. D.; Oskarsson, A.; Ozaki, H.; Ozawa, K.; Pak, R.; Pantuev, V.; Papavassiliou, V.; Park, I. H.; Park, J. S.; Park, S.; Park, S. K.; Pate, S. F.; Patel, L.; Patel, M.; Peng, J.-C.; Perepelitsa, D. V.; Perera, G. D. N.; Peressounko, D. Yu.; Perry, J.; Petti, R.; Pinkenburg, C.; Pinson, R.; Pisani, R. P.; Purschke, M. L.; Qu, H.; Rak, J.; Ramson, B. J.; Ravinovich, I.; Read, K. F.; Reynolds, D.; Riabov, V.; Riabov, Y.; Richardson, E.; Rinn, T.; Riveli, N.; Roach, D.; Rolnick, S. D.; Rosati, M.; Rowan, Z.; Rubin, J. G.; Ryu, M. S.; Sahlmueller, B.; Saito, N.; Sakaguchi, T.; Sako, H.; Samsonov, V.; Sarsour, M.; Sato, S.; Sawada, S.; Schaefer, B.; Schmoll, B. K.; Sedgwick, K.; Seele, J.; Seidl, R.; Sekiguchi, Y.; Sen, A.; Seto, R.; Sett, P.; Sexton, A.; Sharma, D.; Shaver, A.; Shein, I.; Shibata, T.-A.; Shigaki, K.; Shimomura, M.; Shoji, K.; Shukla, P.; Sickles, A.; Silva, C. L.; Silvermyr, D.; Singh, B. K.; Singh, C. P.; Singh, V.; Skolnik, M.; Slunečka, M.; Snowball, M.; Solano, S.; Soltz, R. A.; Sondheim, W. E.; Sorensen, S. P.; Sourikova, I. V.; Stankus, P. W.; Steinberg, P.; Stenlund, E.; Stepanov, M.; Ster, A.; Stoll, S. P.; Stone, M. R.; Sugitate, T.; Sukhanov, A.; Sumita, T.; Sun, J.; Sziklai, J.; Takahara, A.; Taketani, A.; Tanaka, Y.; Tanida, K.; Tannenbaum, M. J.; Tarafdar, S.; Taranenko, A.; Tennant, E.; Tieulent, R.; Timilsina, A.; Todoroki, T.; Tomášek, M.; Torii, H.; Towell, C. L.; Towell, M.; Towell, R.; Towell, R. S.; Tserruya, I.; van Hecke, H. W.; Vargyas, M.; Vazquez-Zambrano, E.; Veicht, A.; Velkovska, J.; Vértesi, R.; Virius, M.; Vrba, V.; Vznuzdaev, E.; Wang, X. R.; Watanabe, D.; Watanabe, K.; Watanabe, Y.; Watanabe, Y. S.; Wei, F.; Whitaker, S.; White, A. S.; Wolin, S.; Woody, C. L.; Wysocki, M.; Xia, B.; Xue, L.; Yalcin, S.; Yamaguchi, Y. L.; Yanovich, A.; Yokkaichi, S.; Yoo, J. H.; Yoon, I.; You, Z.; Younus, I.; Yu, H.; Yushmanov, I. E.; Zajc, W. A.; Zelenski, A.; Zhou, S.; Zou, L.; Phenix Collaboration
2016-01-01
PHENIX measurements are presented for the cross section and double-helicity asymmetry (AL L ) in inclusive π0 production at midrapidity from p +p collisions at √{s }=510 GeV from data taken in 2012 and 2013 at the Relativistic Heavy Ion Collider. The next-to-leading-order perturbative-quantum-chromodynamics theory calculation is in excellent agreement with the presented cross section results. The calculation utilized parton-to-pion fragmentation functions from the recent DSS14 global analysis, which prefer a smaller gluon-to-pion fragmentation function. The π0AL L results follow an increasingly positive asymmetry trend with pT and √{s } with respect to the predictions and are in excellent agreement with the latest global analysis results. This analysis incorporated earlier results on π0 and jet AL L and suggested a positive contribution of gluon polarization to the spin of the proton Δ G for the gluon momentum fraction range x >0.05 . The data presented here extend to a currently unexplored region, down to x ˜0.01 , and thus provide additional constraints on the value of Δ G .
A study of isospin symmetry breaking in carbon 12 with 50 MeV pions
International Nuclear Information System (INIS)
Applegate, J.M.
1993-03-01
In the first experiment to use the superconducting RF cavity at LAMPF known as the Scruncher, cross sections have been measured for the 1+ doublet in 12 C by 50 MeV πr ± scattering. The cross section ratio of the isoscalar to the isovector states was found to be 6.8 ± 1.3 for π + + scattering and 3.9 ± 1.4 for π - scattering. These ratios give an isospin mixing matrix element H 01 , of 119 ± 40 key, in good agreement with the average value of 123 ± 26 key deduced from previous pion-scattering data and with values deduced from other probes. The ratio of π + + p to π - + p cross sections was determined experimentally to be 2.60 ± 0.11, in agreement with a theoretical value of 2.85. The agreement of these results indicates that the impulse approximation is valid at 50 MeV. Cross sections were also measured for the elastic and collective states in 12 C and were generally described well by distorted wave Born approximation calculations published previously
Studying the Puzzle of the Pion Nucleon Sigma Term
Kane, Christopher; Lin, Huey-Wen
2017-09-01
The pion nucleon sigma term (σπN) is a fundamental parameter of QCD and is integral in the experimental search for dark matter particles as it is used to calculate the cross section of interactions between potential dark matter candidates and nucleons. Recent calculations of this term from lattice-QCD data disagree with calculations done using phenomenological data. This disparity is large enough to cause concern in the dark matter community as it would change the constraints on their experiments. We investigate one potential source of this disparity by studying the flavor dependence on LQCD data used to calculate σπN. To calculate σπN, we study the nucleon mass dependence on the pion mass and implement the Hellmann-Feynman Theorem. Previous calculations only consider LQCD data that accounted for 2 and 3 of the lightest quarks in the quark sea. We extend this study by using new high statistic data that considers 2, 3, and 4 quarks in the quark sea to see if the exclusion of the heavier quarks can account for this disparity. National Science Foundation.
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
Low energy pion--nucleon and pion--deuteron interactions
International Nuclear Information System (INIS)
Burman, R.L.
1975-01-01
This survey concentrates upon current experiments in the fields of pion-nucleon and pion-deuteron interactions, for low-energy incident pions--below 300 MeV. The discussion is restricted to very recent work. The topics to be covered are: π +- p → π +- p, Elastic Scattering; π +- p → π +- pγ, Bremsstrahlung; π + d → pp, Absorption; π d → π + d, Elastic Scattering; and π + d → π + pn, Breakup. (14 figures) (U.S.)
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)
High resolution study of the inclusive production of massive muon pairs by intense pion beams
2002-01-01
This experiment measures with high resolution and large acceptance the inclusive production of massive muon pairs with the intense pion beam (up to $10^{10} \\pi/$pulse) in the experimental hall ECN3. The experiment explores extended M$^{2}$/s, x and transverse momentum ranges. The study of the departures of the lepton-pair production cross- section from scaling constitutes a good test of QCD ideas; in the framework of the 'Drell-Yan' process, the experiment allows a detailed study of the pion parton distribution functions. The detector consists of a beam dump, a pulsed toroidal a magnet, MWPC's and scintillator hodoscopes. Its $\\sim 2$% mass resolution at 10 GeV is adequate for the substraction of resonances in the high-mass region.
Measurement of inverse pion photoproduction at energies spanning the N(1440) resonance
International Nuclear Information System (INIS)
Shafi, A.; Strakovsky, I.I.; Briscoe, W.J.; Arndt, R.A.; Bennhold, C.; Workman, R.L.; Prakhov, S.; Nefkens, B.M.K.; Clajus, M.; Marusic, A.; McDonald, S.; Phaisangittisakul, N.; Price, J.W.; Tippens, W.B.; Allgower, C.E.; Spinka, H.; Bekrenev, V.; Kulbardis, A.; Kozlenko, N.; Kruglov, S.
2004-01-01
Differential cross sections for the process π - p→γn have been measured at Brookhaven National Laboratory's Alternating Gradient Synchrotron with the Crystal Ball multiphoton spectrometer. Measurements were made at 18 pion momenta from 238 to 748 MeV/c, corresponding to E γ for the inverse reaction from 285 to 769 MeV. The data have been used to evaluate the γn multipoles in the vicinity of the N(1440) resonance. We compare our data and multipoles to previous determinations
International Nuclear Information System (INIS)
Takahashi, Toshiyuki
1995-11-01
Differential cross sections of the pion elastic scattering in the GeV/c region were systematically measured by using a newly constructed superconducting kaon spectrometer at KEK. The pion incident momenta were 610, 710, 790, and 895 MeV/c for 12 C(π - , π - ) 12 C and 790 MeV/c for 208 Pb(π ± , π ± ) 208 Pb. We have obtained the cross sections with absolute normalization uncertainty of about 10%. The π - -p scattering data measured with a CH target agree well with the phase-shift calculations, which confirms the accuracy of the absolute values of the cross sections. The angular distributions of the differential cross sections for 12 C were compared with calculations by a first-order optical potential model. The calculation reproduces the data at forward scattering-angle regions except at 610 MeV/c, although it underestimates at large-angle region. The present data at 790 MeV/c are in between the BNL data at 800 MeV/c and the calculation, although our data are consistent with the BNL data within their systematic errors. The incident momentum dependence of σ total , σ R , and σ elastic , which were extracted by fitting the angular distributions, is different from that of the calculation with free π-N elementary amplitudes. It is well explained by taking account of Fermi motion. The 208 Pb data are well reproduced by the optical potential model. The root mean square radius of the neutron distribution has been deduced from π + and π - elastic scattering for the first time. Although the result has a model ambiguity, it agrees with that deduced from the proton elastic scattering. It is, however, smaller than the prediction of the relativistic Hartree calculation. (author). 55 refs
Study of the p(e,e'π+)n electro-production reaction: form factor and electromagnetic radius of pion
International Nuclear Information System (INIS)
Michel, Bernard
1977-01-01
After having recalled the definitions and theoretical knowledge on the form factor and electromagnetic radius of hadron and pion, and discussed the relationship between electro-production and form factor for the pion, this research thesis recalls some theoretical aspects of the electro-production process. The author discusses the reaction kinematics and shows how the electro-production cross section can be broken down in terms of photon polarization. Then, he focuses on the cross section dynamic structure. After having recalled the different possible choices for amplitudes, he studies their behaviour, firstly within the framework of the Born approximation, and then within the framework of commonly used models, notably to take the resonant part of the phenomenon into account. The limits of the different models are outlined. The second part addresses the study of forward electro-production. The author shows how the pion form factor can be simply optimized. The author describes the experimental arrangement: electron beam and liquid hydrogen target, detection system, normalisation device, data acquisition logics. In the next chapter, the author describes how data are recorded until the obtainment of N electro-production events. Results are then interpreted in terms of form factor and electromagnetic radius. They are also compared with published results obtained with other electro-production experiments or measurements based on other processes [fr
Coherent pion production induced by 300 MeV and 600 MeV deuterons
International Nuclear Information System (INIS)
Aslanides, E.; Bergdolt, A.M.; Bing, O.; Fassnacht, P.; Hibou, F.
1982-01-01
Experimental data on (d,π - ) reactions at 300 and 600 MeV incident energy are presented. Inclusive spectra on 6 Li, 9 Be and 10 B targets near the kinematical limit do not show the usual scaling behaviour. For the two-body reaction 6 Li (d,π - ) 8 B the lowest-energy discrete states of the final nucleus were clearly resolved and the cross sections for pion production leading to those states have been determined. (orig.)
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
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.)
Connected and disconnected contractions in pion-pion scattering
Acharya, Neramballi Ripunjay; Guo, Feng-Kun; Meißner, Ulf-G.; Seng, Chien-Yeah
2017-09-01
We show that the interplay of chiral effective field theory and lattice QCD can be used in the evaluation of so-called disconnected diagrams, which appear in the study of the isoscalar and isovector channels of pion-pion scattering and have long been a major challenge for the lattice community. By means of partially-quenched chiral perturbation theory, we distinguish and analyze the effects from different types of contraction diagrams to the pion-pion scattering amplitude, including its scattering lengths and the energy-dependence of its imaginary part. Our results may be used to test the current degree of accuracy of lattice calculation in the handling of disconnected diagrams, as well as to set criteria for the future improvement of relevant lattice computational techniques that may play a critical role in the study of other interesting QCD matrix elements.
Pion-nucleon interactions in low energy region
International Nuclear Information System (INIS)
Hiroshige, Noboru; Tsujimura, Tadakuni.
1977-01-01
Pion-nucleon interactions in low energy region (below 320 MeV in kinetic energy) are investigated on the basis of the one-particle-exchange model. The model is directly compared with the experimental data, i.e., differential cross sections and recoil nucleon polarizations, since phase shifts have not been uniquely determined. It is shown that these experimental data can be well reproduced by taking account of N (nucleon), Δ 33 , N 11 , N 13 , rho, f 0 and S (scalar meson) in the intermediate state. Some comments are given on the coupling constants which are determined so as to minimize chi-squared value (chi 2 ). Our predicted phase shifts for s-, p- and d-waves are also compared with other authors'. (auth.)
Can one distinguish τ-neutrinos from antineutrinos in neutral-current pion production processes?
International Nuclear Information System (INIS)
Hernandez, E.; Nieves, J.; Valverde, M.
2007-01-01
A potential way to distinguish τ-neutrinos from antineutrinos, below the τ-production threshold, but above the pion production one, is presented. It is based on the different behavior of the neutral-current pion production off the nucleon, depending on whether it is induced by neutrinos or antineutrinos. This procedure for distinguishing τ-neutrinos from antineutrinos neither relies on any nuclear model, nor it is affected by any nuclear effect (distortion of the outgoing nucleon waves, etc.). We show that neutrino-antineutrino asymmetries occur both in the totally integrated cross sections and in the pion azimuthal differential distributions. To define the asymmetries for the latter distributions we just rely on Lorentz-invariance. All these asymmetries are independent of the lepton family and can be experimentally measured by using electron or muon neutrinos, due to the lepton family universality of the neutral-current neutrino interaction. Nevertheless and to estimate their size, we have also used the chiral model of [E. Hernandez, J. Nieves, M. Valverde, hep-ph/0701149] at intermediate energies. Results are really significant since the differences between neutrino and antineutrino induced reactions are always large in all physical channels
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).
The pion-deuteron forward elastic amplitude in the non-overlapping potentials model
International Nuclear Information System (INIS)
Butterworth, D.S.
1978-01-01
The pion-deuteron forward elastic amplitude has been calculated in the non-overlapping potentials model, which enables a description of off-shell propagation effects in terms of on-shell amplitudes. Calculations include spin, isospin and deuteron D-state probability effects. Two energy regions are considered. First the pion-nucleon P 33 resonance region, where, using a formalism developed by Agassi and Gal (Ann. Phys.; 75:56 (1973) and 94:184 (1975)), the full multiple-scattering series is summed in an approximation of P 33 wave dominance of the higher-order scatterings. Second, for the subsequent highest-energy region, the double-scattering term only is calculated. Fermi smearing effects are included in both cases. Predictions for the total cross section, its dependence on the deuteron alignment and the real part of the forward elastic amplitude are compared with those of Glauber theory, and data where available. Convergence of the multiple-scattering series is also discussed. (author)
Quasifree pion electroproduction from nuclei in the {Delta} region
Energy Technology Data Exchange (ETDEWEB)
Lee, F X [TRIUMF, Vancouver, BC (Canada); Wright, L E [Ohio Univ., Inst. of Nuclear and Particle Physics, Dept. of Physics, Athens, OH (United States); Bennhold, C [George Washington Univ., Center for Nuclear Studies, Dept. of Physics, Washington, DC (United States)
1995-10-01
We present calculations of the reaction {Alpha} (e, e{sup 1}{pi} N)B in the distorted wave impulse approximation. The reaction allows for the study of the production process in the nuclear medium without being obscured by the details of nuclear transition densities. First, a pion electroproduction operator suitable for nuclear calculations is obtained by extending the Blomqvist-Laget photoproduction operator to the virtual photon case. The operator is gauge invariant, unitary, reference frame independent, and describes the existing data reasonably well. Then it is applied in nuclei to predict nuclear cross sections under a variety of kinematic arrangements. Issues such as the effects of gauge-fixing, the interference of the {Delta} resonance with the background, sensitivities to be guadrupole component of the {Delta} excitation and to the electromagnetic form factors, the role of final-state interactions, are studied in detail. Methods on how to experimentally separate the various pieces in the coincidence cross section are suggested. Finally, the model is compared to recent SLAC experiment. (authors) 35 refs., 22 figs.
International Nuclear Information System (INIS)
Carlson, A.D.
1984-01-01
The accuracy of neutron cross-section measurement is limited by the uncertainty in the standard cross-section and the errors associated with using it. Any improvement in the standard immediately improves all cross-section measurements which have been made relative to that standard. Light element, capture and fission standards are discussed. (U.K.)
A Measurement of Neutrino-Induced Charged-Current Neutral Pion Production
Energy Technology Data Exchange (ETDEWEB)
Nelson, Robert H. [Univ. of Colorado, Boulder, CO (United States)
2010-01-01
This work presents the first comprehensive measurement of neutrino-induced charged-current neutral pion production (CCπ^{0}) off a nuclear target. The Mini Booster Neutrino Experiment (MiniBooNE) and Booster Neutrino Beam (BNB) are discussed in detail. MiniBooNE is a high-statistics (~ 1, 000, 000 interactions) low-energy (E_{v}ϵ 2 0.5 - 2.0 GeV) neutrino experiment located at Fermilab. The method for selecting and reconstructing CCπ^{0} events is presented. The π^{0} and μ^{-} are fully reconstructed in the final state allowing for the measurement of, among other things, the neutrino energy. The total observable CCπ^{0} cross-section is presented as a function of neutrino energy, along with five differential cross-sections in terms of the final state kinematics and Q^{2}. The results are combined to yield a flux-averaged total cross-section of <σ>_{Φ} = (9.2 ± 0.3_{stat.} ± 1.5_{syst.}) × 10^{-39} cm^{2}/CH_{2} at energy 965 MeV. These measurements will aid future neutrino experiments with the prediction of their neutrino interaction rates.
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
International Nuclear Information System (INIS)
Laville, J.-L.
1976-01-01
The creation of a high intensity beam of monokinetic neutrons obtained from stripping deuterons extracted from the synchrotron Saturne (C.E.N., Saclay) has allowed to measure with good statistical accuracy 43 momentum spectra of the final proton of the inclusive reaction np→pX at 1.39, 1.56, 1.73 and 1.90GeV/c (approximately 10 spectra per incident momentum). The final proton was analyzed with a magnetic spectrometer in the angular region between 0 and 20 deg in the laboratory. The set of results has been the object of two analyses: at first, the experimental spectra were compared with a pion exchange model modified by the off-shell parametrization of BENECKE-DURR-PILKUHN overall, this model correctly reproduces the measured spectra, both in form and absolute normalization. In the second analysis, the total and differential cross sections of the np→pΔ 33 0 channel were determined from the spectra measured using a subtraction procedure. The differential cross sections obtained in this way show an angular dependence that differs from the predictions of the pion exchange model. It is concluded that, at low energy, near its threshold, the reaction NN→NΔ 33 involves a set of more complex mechanisms than pion exchange alone, even if the latter remains dominant [fr
Energy Technology Data Exchange (ETDEWEB)
Zagrebelnyy, Vitaly [DESY Hamburg Notkestrasse 85 (Germany)
2014-07-01
Beam-spin asymmetries in the azimuthal distribution of pions, kaons, protons and antiprotons in semi-inclusive deep inelastic scattering (SIDIS) extracted from 2000-2007 HERMES data are presented. The asymmetries were measured in the kinematic region Q{sup 2}>1 GeV{sup 2}, W{sup 2} > 10 GeV{sup 2}, 0.1
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)
Huefner, J.
1975-01-01
Are pions a good tool to study nuclei. If the emphasis of this question rests on ''tool'', the answer must be ''not yet.'' The reason: one does not even understand how a pion interacts with a nucleus. This is part of the many-body problem for strongly interacting particles and its study is a basic problem in physics. One must investigate questions like: Can one understand pion-nucleus interactions from pion-nucleon physics. How does a Δ-resonance look in nuclei. Once one has solved those basic problems, there will be spinoffs in medical, technical and nuclear areas. Then pions can be used as a tool to study nuclear properties
International Nuclear Information System (INIS)
Sadler, M.E.; Isenhower, L.D.
1987-01-01
This report describes the progress made in the past year and future plans for the pion scattering programs in which Abilene Christian University is collaborating. The experiments are conducted at the Clinton P. Anderson Meson Physics Facility at Los Alamos (LAMPF). The experiments are performed in collaboration with UCLA, George Washington University, LAMPF Groups MP-4, MP-10 and MP-13, and Catholic University. The measurements include: (1) a complete set of observables in the pion-nucleon system in the momentum interval 400 to 700 MeV/c, (2) differential cross sections at low energy for pion-nucleon charge exchange, and (3) elastic and inelastic scattering of π/sup +-/ on 3 H and 3 He
International Nuclear Information System (INIS)
Luckstead, S.C.
1978-09-01
Differential production cross sections for multiply charged fragments from 800-MeV proton-induced spallation of 12 C, 27 Al, and natural Ni were measured at 30 and 90 degrees. The ion fragments were identified by use of time-of-flight, ΔE--E detector telescope capable of complete particle identification for energies as low as .25 MeV/nucleon. The very short ranges of the particles of interest required the construction of very thin detectors with minimal deadlayer material. The time-pick-off detectors and gas ionization chamber developed are unique, and represent the state-of-the-art in fast timing for time-of-flight measurements and in construction of thin detectors. The resolutions achieved allowed the cross sections of 3 He, 4 He, 6 Li, 7 Li, 7 Be, 9 Be, 10 Be, 10 B, 11 B, 11 C, 12 C, and 13 C to be determined, along with those of nitrogen and oxygen without isotope separation. The cross sections were found to have weak angular dependence. Consequently, pseudo cross sections were calculated from the 90 0 data by integrating the differential cross sections from 0 to 25 MeV for each product and multiplying by 4π. Pseudo theoretical cross sections were similarly calculated from theoretical differential cross sections. These differential cross sections were calculated by use of a Monte Carlo computer code which incorporated the cascade-evaporation model of high-energy nuclear reactions. Implications are drawn for modifications of the model. The results suggest reducing the transparency of the struck nucleus to pions produced in the cascade stage of the reaction model in order that a higher excitation energy be left for the evaporation stage. Also, there is some evidence that evaporations of nuclear aggregates more massive than 4 He occur. Inclusion of such evaporations should improve the model. 82 figures, 1 table
Cross sections for atmospheric corrections
International Nuclear Information System (INIS)
Meyer, J.P.; Casse, M.; Westergaard, N.
1975-01-01
A set of cross sections for spallation of relativistic nuclei is proposed based on (i) the best available proton cross sections, (ii) an extrapolation to heavier nuclei of the dependence on the number of nucleons lost of the 'target factor' observed for C 12 and O 16 by Lindstrom et al. (1975), in analogy with Rudstam's formalism, and (iii) on a normalization of all cross sections to the total cross sections for production of fragments with Asub(f) >= 6. The obtained cross sections for peripheral interactions are not inconsistent with simple geometrical considerations. (orig.) [de
Effect of pion mean-field on properties of pions and kaons from heavy-ion collisions
International Nuclear Information System (INIS)
Zheng Yuming; Chu Zili; Wang Hui; Sa Benhao
1996-01-01
The Relativistic Vlasov-Uehling-Uhlenbeck (RVUU) model is used to study the properties of pions and kaons produced in heavy ion collisions. We include the nuclear medium effect on kaon and pion in the model, and simulate pion production and subthreshold kaon production in Kr + Zr reactions at 1 GeV/u. The calculated results show that the attractive pion optical potential changes the final-state pion momentum spectrum, enhancing the yield of pions with low transverse momenta. At the same time it also increases the kaon abundance and modifies the kaon momentum distribution
Single-pion production in pp collisions at 0.95 GeV/c (II)
International Nuclear Information System (INIS)
Abd El-Samad, S.; Bilger, R.; Clement, H.; Dietrich, M.; Doroshkevich, E.; Ehrhardt, K.; Erhardt, A.; Kress, J.; Meier, R.; Wagner, G.J.; Weidlich, U.; Zhang, G.; Brinkmann, K.T.; Freiesleben, H.; Jaekel, R.; Jakob, B.; Karsch, L.; Kuhlmann, E.; Schulte-Wissermann, M.; Sun, G.Y.; Dshemuchadse, S.; Eyrich, W.; Hauffe, J.; Schroeder, W.; Stinzing, F.; Waechter, J.; Wagner, M.; Wirth, S.; Filippi, A.; Marcello, S.; Fritsch, M.; Geyer, R.; Gillitzer, A.; Hesselbarth, D.; Kilian, K.; Marwinski, S.; Morsch, H.P.; Ritman, J.; Roderburg, E.; Moeller, K.; Naumann, L.; Schoenmeier, P.; Wilms, A.
2009-01-01
The single-pion production reactions pp→dπ + , pp→npπ + and pp→ppπ 0 were measured at a beam momentum of 0.95GeV/c (T p ∼400 MeV) using the short version of the COSY-TOF spectrometer. The central calorimeter provided particle identification, energy determination and neutron detection in addition to time-of-flight and angle measurements from other detector parts. Thus all pion production channels were recorded with 1-4 overconstraints. The main emphasis is put on the presentation and discussion of the npπ + channel, since the results on the other channels have already been published previously. The total and differential cross-sections obtained are compared to theoretical calculations. In contrast to the ppπ 0 channel we observe in the npπ + channel a strong influence of the Δ excitation. In particular, the pion angular distribution exhibits a (3 cos 2 Θ+1)-dependence, typical for a pure s-channel Δ excitation and identical to that observed in the dπ + channel. Since the latter is understood by a s-channel resonance in the 1 D 2 pn partial wave, we discuss an analogous scenario for the pnπ + channel. (orig.)
International Nuclear Information System (INIS)
Sadler, M.E.; Isenhower, L.D.
1989-01-01
This report summarizes the progress made from the end of the last reporting period (1 December 1987) to the present (1 March 1989) and presents future plans for the experimental programs in which Abilene Christian University is collaborating. The measurements include: a complete set of observables in the pion-nucleon system in the momentum interval 400--700 MeV/c, differential cross sections at low energy for pion-nucleon charge exchange, and elastic and inelastic scattering of π/sup +-/ on 3 H and 3 He
Energy Technology Data Exchange (ETDEWEB)
Devereux, M.J.
1979-05-01
Elastic pion scattering from /sup 9/Be, /sup 28/Si, /sup 58/Ni, and /sup 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.
International Nuclear Information System (INIS)
Kolanoski, H.
1983-03-01
Recent results on two-photon physics from the Tasso experiment are presented: the measurement of the two-photon production of Kanti K with the determination of the #betta##betta#-width of the f'(1515), an analysis of the angular correlations in the reaction #betta##betta#->rho 0 rho 0 ->π + π - π + π - and the observation of a narrow structure in the four pion mass spectrum around 2.1 GeV. In a separate part the experimental results on the total cross section for hadron production by two photons are reviewed. (orig.)
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.
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.
International Nuclear Information System (INIS)
Funsten, H.O.
1979-01-01
This is a modification of the Eisenstein-Miller program for calculation of collective inelastic pion-nucleus differential cross sections using free π-N scattering amplitudes. This revision permits the additional use of microscopic (shell model) proton and neutron form factors. It also incorporates separate proton and neutron radii for the nuclear density rho(r) generating the distorted wave optical potential. (Auth.)
The scattering of pions on polarized helium-three in the vicinity of delta resonance
International Nuclear Information System (INIS)
Braun, M.A.; Suslov, V.M.
1996-01-01
In the fixed-centers approximation the amplitude of the pion interaction with 3 H and 3 He is obtained. The N N interaction is neglected and for the πN interaction only the contribution of the P 33 state is included. The nuclear coordinate wave function was taken as a sum of Gaussian. The differential cross sections and asymmetries for elastic π -3 H(π +3 He) process at T π = 180 MeV are calculated. The results are compared with experimental data [ru
Multitrajectory eikonal cross sections
International Nuclear Information System (INIS)
Turner, R.E.
1983-01-01
With the use of reference and distorted transition operators, a time-correlation-function representation of the inelastic differential cross section has recently been used to obtain distorted eikonal cross sections. These cross sections involve straight-line and reference classical translational trajectories that are unaffected by any internal-state changes which have occurred during the collision. This distorted eikonal theory is now extended to include effects of internal-state changes on the translational motion. In particular, a different classical trajectory is associated with each pair of internal states. Expressions for these inelastic cross sections are obtained in terms of time-ordered cosine and sine memory functions using the Zwanzig-Feshbach projection-operator method. Explicit formulas are obtained in the time-disordered perturbation approximation
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
Energy Technology Data Exchange (ETDEWEB)
dos Reis, Alberto Correa [Rio de Janeiro, CBPF
1992-04-01
This work a presents a measurement of the total cross section for the charmed baryon $\\Lambda_c$ times the branching fraction of the mode $\\Lambda_c \\to pK\\bar{\\mu}$, for the kinematical region $x_F$ > O in $\\pi$-nucleus interactions at 250 GeV/c. This measurement is made with data from the experiment E769, collected during 1987/1988 at the FERMILAB Tagged Photon Laboratory. A segmented target of berillium, aluminum, copper and tungsten was used. Based on the A dependence measurement, made by E769, and on the available branching fractions, the total cross section per nucleon is calculated. The result is compared with other experiments and with some theoretical predictions inspired on QCD.
Minnesota Department of Natural Resources — FEMA Cross Sections are required for any Digital Flood Insurance Rate Map database where cross sections are shown on the Flood Insurance Rate Map (FIRM). Normally...
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
Pion correlations in relativistic heavy ion collisions at Heavy Ion Spectrometer Systems (HISS)
Energy Technology Data Exchange (ETDEWEB)
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.
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
International Nuclear Information System (INIS)
Sadler, M.E.
1987-03-01
This report describes the progress made in the past year in the pion scattering programs in which Abilene Christian University is collaborating. The measurements include (1) a complete set of observables in the pion-nucleon system in the momentum interval 400 to 700 MeV/e, (2) differential cross sections at low energy for pion-nucleon charge exchange, and (3) elastic and inelastic scattering of π +- on 3 H and 3 He. Highlights of the progress in 1986 to 87 include (1) first measurement of the spin rotation parameters A and R for π +- p → π +- p scattering at 427 to 657 MeV/e, for which the principal investigator received support from Associated Western Universities (AWU) and ACU for sabbatical leave in Los Alamos, (2) final publication of the data for the differential cross sections and analyzing powers for π +- p elastic scattering at 378 to 687 MeV/c, (3) final publication of forward-angle differential cross sections for π - p → π 0 n at 101 to 147 MeV/c, and (4) continued development of analysis capabilities on the ACU VAX-11/785, including full implementation of the LAMPF Q system MAPPER and DISSPLA graphics software. TEDI and TEX word processing and the associated hardware to utilize the software. The experiments are conducted at the Clinton P. Anderson Meson Physics Facility at Los Alamos (LAMPF). The experiments are performed in collaboration with UCLA, George Washington University, LAMPF Groups MP-4, MP-10 and MP-13, and Catholic University. 37 refs., 13 figs., 1 tab
Coherent pion production with the 910 MeV 3He beam at the CERN S.C
International Nuclear Information System (INIS)
Aslanides, E.
1979-01-01
The first experiment carried out at the CERN synchrocyclotron, 3 He + nucleus → X + π - , is analysed. The inclusive pion spectrum is given up to the kinematic limit covering cross sections from a few μb/sr MeV/C to 0.1 pb/sr MeV/C. An attempt is made to see how far these results are consistent with an interpretation based on the NN→NNπ process by means of nuclear form factors and by scaling [fr
Pion- and proton-nucleus interactions at intermediate energy
International Nuclear Information System (INIS)
Dehnhard, D.
1992-12-01
We report on scattering and reaction experiments on light nuclei using the π-meson and proton beams from the Los Alamos Meson Physics Facility (LAMPF) and the Indiana University Cyclotron Facility (IUCF). Differential cross sections, cross section asymmetries, and angular correlation functions have been measured in order to test models of the reaction mechanism and of nuclear structure. At LAMPF we have measured asymmetries for pion scattering from polarized 13 C which are uniquely sensitive to the isoscalar spin density. In order to determine details of the reaction mechanism, we have obtained approval for a scattering experiment on polarized 3 He for which the nuclear structure is very well known. We have completed data taking for two studies of elastic scattering of π + from 6 Li and l3 C. The detailed differential cross sections from these experiments will be used to constrain theoretical analyses of previous polarization experiments done at the Pierre-Scherrer-Institute (PSI) and at LAMPF. We have analyzed π-triton coincidence events from the 4 He(π,π' t)p reaction and have found evidence for direct triton knockout from 4 He. We have extended these angular correlation measurements to higher energies and to 2 H and 3 He targets. At IUCF we have performed the first 4 He(p,n) experiment at intermediate energies, T p = 100, 147, and 200 MeV, in a search for previously reported narrow states in 4 Li of widths of ∼ 1 MeV. Within the statistics of the data we have found no evidence for such narrow structures
Comparison of integral cross section values of several cross section libraries in the SAND-II format
International Nuclear Information System (INIS)
Zijp, W.L.; Nolthenius, H.J.
1976-09-01
A comparison of some integral cross-section values for several cross-section libraries in the SAND-II format is presented. The integral cross-section values are calculated with the aid of the spectrum functions for a Watt fission spectrum, a 1/E spectrum and a Maxwellian spectrum. The libraries which are considered here are CCC-112B, ENDF/B-IV, DETAN74, LAPENAS and CESNEF. These 5 cross-section libraries used have all the SAND-II format. Discrepancies between cross-sections in the different libraries are indicated but not discussed
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
Posiadała, Magdalena Zofia
Differential cross sections and mean multiplicities in production processes for low momentum charged pion mesons and protons in p+C interactions at 31 GeV/c measured with the large acceptance NA61/SHINE spectrometer at the CERN SPS are presented. A set of data col- lected during the first NA61/SHINE run in 2007 with a thin graphite target was used for the analysis. The results are presented as a function of laboratory momentum in 10 intervals of the laboratory polar angle covering the range from 0 up to 420 mrad. The spectra are compared with predictions of several hadron production models. Measurements for + and
Pion-nuclear many body problems
International Nuclear Information System (INIS)
Weise, W.
1981-01-01
This chapter examines pion-nucleus scattering data produced at the meson factories in order to gain information about the ''optical'' branches of the pion-nuclear excitation spectrum. Discusses basic meson-baryon effective Lagrangians and elementary processes; pion-baryon vertex form factors; the spin-isospin dependent baryon-baryon interaction; pions in nuclear matter; nuclear spin-isospin correlations; the baryon-hole model; photon-induced excitation of baryon-hole states; high momentum transfer properties of pion-like nuclear states; a response function for pionic low-frequency modes in finite nuclei; and applications. Finds that there is no clear evidence for pionic critical opalescence, as in agreement with the expectation that the minimal density for the appearance of a pion condensate is certainly not lower than two or three times nuclear matter density
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
Relativistic photon-Maxwellian electron cross sections
International Nuclear Information System (INIS)
Wienke, B.R.; Lathrop, B.L.; Devaney, J.J.
1986-01-01
Temperature corrected cross sections, complementing the Klein-Nishina set, are developed for astrophysical, plasma, and transport applications. The set is obtained from a nonlinear least squares fit to the exact photon-Maxwellian electron cross sections, using the static formula as the asymptotic basis. Two parameters are sufficient (two decimal places) to fit the exact cross sections over a range of 0-100 keV in electron temperature, and 0-1 MeV in incident photon energy. The fit is made to the total cross sections, yet the parameters predict both total and differential scattering cross sections well. Corresponding differential energy cross sections are less accurate. An extended fit to (just) the total cross sections, over the temperature and energy range 0-5 MeV, is also described. (author)
Pion scattering from very light nuclei
International Nuclear Information System (INIS)
Berman, B.
1993-01-01
Selected recent elastic and inelastic pion-scattering experiments on 3 H, 3 He, and 4 He will be reviewed. Particular attention will be given to multinucleon or cluster aspects of the data, and to possible comparisons with electron-scattering results. From elastic scattering from 3 H and 3 He at forward angles, one can extract the matter distribution of the paired neutrons in 3 H as well as that of the paired protons in 3 He. At backward angles, scattering from correlated nucleon pairs and/or two-step processes play an important role. For inelastic scattering, the momentum-transfer dependence of the cross section varies strongly with incident energy. Elastic scattering from a polarized 3 He target shows a strong asymmetry near 90 degrees. Elastic scattering from 4 He yields results which cannot be fitted with a simple optical model. An for inelastic scattering from 4 He, analysis of the data requires an important contribution from direct triton knockout
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)
Inclusive production of charged pions in p+C collisions at 158 GeV/c beam momentum
Alt, C; Barna, D; Barr, G; Bartke, Jerzy; Betev, L; Biakowska, H; Blume, C; Boimska, B; Bracinik, J; Bramm, R; Buncic, P; Cerny, V; Christakoglou, P; Chvala, O; Dinkelaker, P; Dolejsi, J; Eckardt, V; Fischer, H G; Flierl, D; Fodor, Z; Foka, P; Friese, V; Gazdzicki, M; Georgopoulos, G; Höhne, C; Karev, A; Kniege, S; Kollegger, T; Kolesnikov, V I; Kornas, E; Kowalski, M; Kraus, I; Kreps, M; Litov, L; Makariev, M; Malakhov, A I; Mateev, M; Melkumov, G L; Mitrovski, M; Pálla, G; Panagiotou, A D; Panayotov, D; Pattison, C; Petridis, A; Renfordt, R; Rybicki, A; Sandoval, A; Schmitz, N; Seyboth, P; Siklér, F; Stock, R; Ströbele, H; Sziklai, J; Szymanski, P; Trubnikov, V; Varga, D; Vassiliou, Maria; Veres, G I; Vesztergombi, G; Vranic, D; Wenig, S; Wetzler, A; Zaranek, J
2007-01-01
The production of charged pions in minimum bias p+C interactions is studied using a sample of 377000 inelastic events obtained with the NA49 detector at the CERN SPS at 158 GeV/c beam momentum. The data cover a phase space area ranging from 0 to 1.8 GeV/c in transverse momentum and from -0.1 to 0.5 in Feynman x. Inclusive invariant cross sections are given on a grid of 270 bins per charge thus offering for the first time a dense coverage of the projectile hemisphere and of the cross-over region into the target fragmentation zone.
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 cross section of charmed hadrons and the nuclear dependence alpha
Energy Technology Data Exchange (ETDEWEB)
Blanco-Covarrubias, Ernesto Alejandro [Autonomous Univ. of San Luis Potosi, San Luis Potosi (Mexico)
2009-12-03
With data from the SELEX experiment we study charm hadro-production. We report the differential production cross sections as function of the longitudinal and transverse momentum, as well as for two different target materials, of 14 charmed hadron and/or their decay modes. This is the most extensive study to date. SELEX is a fixed target experiment at Fermilab with high forward acceptance; it took data during 1996-1997 with 600 GeV/c Σ^{-} and π^{-}, and 540 GeV/c proton and π^{+} beams. It used 5 target foils (two copper and three diamond). We use the results to determine α, used in parametrizing the production cross section as ∞ A^{α}, where A is the mass number of the target nuclei. We found within our statistics that α is independent of the longitudinal momentum fraction x_{F} in the interval 0.1 < x_{F} < 1.0, with α = 0.778 ± 0.014. The average value of α} for charm production by pion beams is α _{meson} = 0.850 ± 0.028. This is somewhat larger than the corresponding average α_{baryon} = 0.755 ± 0.016 for charm production by baryon beams (Σ^{-} and protons).
Integral nucleus-nucleus cross sections
International Nuclear Information System (INIS)
Barashenkov, V.S.; Kumawat, H.
2003-01-01
Expressions approximating the experimental integral cross sections for elastic and inelastic interactions of light and heavy nuclei at the energies up to several GeV/nucleon are presented. The calculated cross sections are inside the corridor of experimental errors or very close to it. Described in detail FORTRAN code and a numerical example of the cross section approximation are also presented
Photon-splitting cross sections
International Nuclear Information System (INIS)
Johannessen, A.M.; Mork, K.J.; Overbo, I.
1980-01-01
The differential cross section for photon splitting (scattering of one photon into two photons) in a Coulomb field, obtained earlier by Shima, has been integrated numerically to yield various differential cross sections. Energy spectra differential with respect to the energy of one of the outgoing photons are presented for several values of the primary photon energy. Selected examples of recoil momentum distributions and some interesting doubly or multiply differential cross sections are also given. Values for the total cross section are obtained essentially for all energies. The screening effect caused by atomic electrons is also taken into account, and is found to be important for high energies, as in e + e - pair production. Comparisons with various approximate results obtained by previous authors mostly show fair agreement. We also discuss the possibilities for experimental detection and find the most promising candidate to be a measurement of both photons, and their energies, at a moderately high energy
Comparison of integral cross section values of several cross section libraries in the SAND-II format
International Nuclear Information System (INIS)
Zijp, W.L.; Nolthenius, H.J.
1978-01-01
A comparison of some integral cross section values for several cross section libraries in the SAND-II format is presented. The integral cross section values are calculated with aid of the spectrum functions for a Watt fission spectrum, a 1/E spectrum and a Maxwellian spectrum. The libraries which are considered here are CCC-112B, ENDF/B-IV, DETAN74, LAPENAS and CESNEF. These 5 cross section libraries used have all the SAND-II format. (author)
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...
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...
International Nuclear Information System (INIS)
Del Duca, V.
1992-11-01
Minijet production in jet inclusive cross sections at hadron colliders, with large rapidity intervals between the tagged jets, is evaluated by using the BFKL pomeron. We describe the jet inclusive cross section for an arbitrary number of tagged jets, and show that it behaves like a system of coupled pomerons
High $p_{T}$ charged-pion production in Pb-Au collisions at 158 AGeV/c
Agakichiev, G; Braun-Munzinger, P; Drees, A; Esumi, S C; Faschingbauer, U; Fraenkel, Zeev; Fuchs, C; Glässel, P; Pérez de los Heros, C; Holl, P; Jung, C; Lenkeit, B C; Messer, F; Messer, M; Panebratsev, Yu A; Pfeiffer, A; Rak, J; Ravinovich, I; Razin, S V; Rehak, P; Richter, M; Saveljic, N; Schükraft, Jürgen; Shimansky, S S; Seipp, W; Socol, E; Specht, H J; Stachel, J J; Tel-Zur, G; Tserruya, Itzhak; Ullrich, T S; Voigt, C A; Weber, C; Wessels, J P; Wienold, T; Wurm, J P; Yurevich, V I
2000-01-01
The CERES/Na45 experiment at CERN SPS measured transverse momentum spectra ofcharged-pions in the range 1
Electron collision cross sections of mercury
International Nuclear Information System (INIS)
Suzuki, Susumu; Kuzuma, Kiyotaka; Itoh, Haruo
2006-01-01
In this paper, we propose a new collision cross section set for mercury which revises the original set summarized by Hayashi in 1989. Hanne reported three excitation collision cross sections (6 3 P 0 , 6 3 P 1 , 6 3 P 2 ) determined from an electron beam experiment in 1988. As a matter for regret, no attentive consideration was given to combining these three excitation cross sections with the cross section set of Hayashi. Therefore we propose a new set where these three excitation cross sections are included. In this study, other two excitation cross sections (6 1 P 1 , 6 3 D 3 ) except for the three excitation collision cross sections (6 3 P 0 , 6 3 P 1 , 6 3 P 2 ) are taken from the original set of Hayashi. The momentum transfer cross section and the ionization collision cross section are also taken from Hayashi. A Monte Carlo Simulation (MCS) technique is applied for evaluating our new cross section set. The present results of the electron drift velocity and the ionization coefficient are compared to experimental values. Agreement is secured in relation to the electron drift velocity for 1.5 Td 2 ) is the reduced electric field, E (V/cm) is the electric field, N (1/cm 3 ) is the number density of mercury atoms at 0degC, 1 Torr, E/N is also equal to 2.828 x 10 -17 E/p 0 from the relation of the ideal gas equation, p 0 (Torr) is gas pressure at 0degC, 1 Torr=1.33322 x 10 -2 N/cm -2 and 10 -17 V/cm 2 is called 1 Td. Thus it is ensured that our new cross section set is reasonable enough to be used up to 100 eV when considering with the electron drift velocity and the ionization coefficient. (author)
Pion condensation in symmetric nuclear matter
International Nuclear Information System (INIS)
Shamsunnahar, T.; Saha, S.; Kabir, K.; Nath, L.M.
1991-01-01
We have investigated the possibility of pion condensation in symmetric nuclear matter using a model of pion-nucleon interaction based essentially on chiral SU(2) x SU(2) symmetry. We have found that pion condensation is not possible for any finite value of the density. Consequently, no critical opalescence phenomenon is likely to be seen in pion-nucleus scattering nor is it likely to be possible to explain the EMC effect in terms of an increased number of pions in the nucleus. (author)
Transverse momentum dependence of semi-inclusive pion production
Energy Technology Data Exchange (ETDEWEB)
Mkrtchyan, H. [Yerevan Physics Institute, Yerevan (Armenia); Bosted, P.E. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); University of Massachusetts Amherst, Amherst, MA 01003 (United States)], E-mail: bosted@jlab.org; Adams, G.S. [Rensselaer Polytechnic Institute, Troy, NY 12180 (United States); Ahmidouch, A. [North Carolina A and T State University, Greensboro, NC 27411 (United States); Angelescu, T. [Bucharest University, Bucharest (Romania); Arrington, J. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Asaturyan, R. [Yerevan Physics Institute, Yerevan (Armenia); Baker, O.K. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Hampton University, Hampton, VA 23668 (United States); Benmouna, N. [George Washington University, Washington, D.C. 20052 (United States); Bertoncini, C. [Vassar College, Poughkeepsie, NY 12604 (United States); Blok, H.P. [Vrije Universiteit, 1081 HV Amsterdam (Netherlands); Boeglin, W.U. [Florida International University, University Park, FL 33199 (United States); Breuer, H. [University of Maryland, College Park, MA 20742 (United States); Christy, M.E. [Hampton University, Hampton, VA 23668 (United States); Connell, S.H. [University of the Witwatersrand, Johannesburg (South Africa); Cui, Y. [University of Houston, Houston, TX 77204 (United States); Dalton, M.M. [University of the Witwatersrand, Johannesburg (South Africa); Danagoulian, S. [North Carolina A and T State University, Greensboro, NC 27411 (United States); Day, D. [University of Virginia, Charlottesville, VA 22901 (United States); Dodario, T. [University of Houston, Houston, TX 77204 (United States)] (and others)
2008-07-03
Cross sections for semi-inclusive electroproduction of charged pions ({pi}{sup {+-}}) from both proton and deuteron targets were measured for 0.2
Background-cross-section-dependent subgroup parameters
International Nuclear Information System (INIS)
Yamamoto, Toshihisa
2003-01-01
A new set of subgroup parameters was derived that can reproduce the self-shielded cross section against a wide range of background cross sections. The subgroup parameters are expressed with a rational equation which numerator and denominator are expressed as the expansion series of background cross section, so that the background cross section dependence is exactly taken into account in the parameters. The advantage of the new subgroup parameters is that they can reproduce the self-shielded effect not only by group basis but also by subgroup basis. Then an adaptive method is also proposed which uses fitting procedure to evaluate the background-cross-section-dependence of the parameters. One of the simple fitting formula was able to reproduce the self-shielded subgroup cross section by less than 1% error from the precise evaluation. (author)
Cross-section methodology in SIMMER
International Nuclear Information System (INIS)
Soran, P.D.
1975-11-01
The cross-section methodology incorporated in the SIMMER code is described. Data base for all cross sections is the ENDF/B system with various progressing computer codes to group collapse and modify the group constants which are used in SIMMER. Either infinitely dilute cross sections or the Bondarenko formalism can be used in SIMMER. Presently only a microscopic treatment is considered, but preliminary macroscopic algorithms have been investigated
Cross-section methodology in SIMMER
International Nuclear Information System (INIS)
Soran, P.D.
1976-05-01
The cross-section methodology incorporated in the SIMMER code is described. Data base for all cross sections is the ENDF/B system with various progressing computer codes to group collapse and modify the group constants which are used in SIMMER. Either infinitely dilute cross sections or the Bondarenko formalism can be used in SIMMER. Presently only a microscopic treatment is considered, but preliminary macroscopic algorithms have been investigated
Corrections to the one-pion exchange amplitudes for the reaction np→pΔsub(33)sup(deg)
International Nuclear Information System (INIS)
Ferraz De Camargo, A.; Laville, J.L.
1978-01-01
A simple modified one-pion exchange model is applied to the analysis of the reaction np→pΔsub(33)sup(deg) from 1.39 to 1.90GeV/c. It is shown that important corrections to the evasive amplitudes can account for the turnover observed in the differential cross-section and rather good fits are obtained. Such corrections do not agree with the prescription known as ''poor man's absorption''. The results for the density matrix elements are briefly 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).
International Nuclear Information System (INIS)
Borzov, I.N.; Sapershtejn, Eh.E.; Tolokonnikov, S.V.; Fayans, S.A.
1981-01-01
The review of contemporary state of the π-condensation in nuclei problem is presented. The problem has been considered in the framework of the finite Fermi system theory. Formulated are the theory equations with a separated single-pion exchange. Determinated are stability conditions in relation to the π-condensation in finite nuclei. Data which testify to the π-condensate absence in nuclei are presented. The analysis of spectroscopic nuclei characteristics (magnetic moments, M1-transition probabilities, etc. which shows the nuclei closeness to the π-condensate instability point is carried out. Precritical effects in nucleon and electron scattering are discussed. In particular, the results of calculation of differential cross sections of inelastic proton scattering with production of 208 Pb and 12 C excited states as well as 208 Pb and 12 C excited state magnetic form factors at inelastic electron scattering by nuclei are presented. The possibility of nuclei closeness to the finite Fermi system theory is predicted [ru
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
Pion-nucleus double charge exchange and the nuclear shell model
International Nuclear Information System (INIS)
Auerbach, N.; Gibbs, W.R.; Ginocchio, J.N.; Kaufmann, W.B.
1988-01-01
The pion-nucleus double charge exchange reaction is studied with special emphasis on nuclear structure. The reaction mechanism and nuclear structure aspects of the process are separated using both the plane-wave and distorted-wave impulse approximations. Predictions are made employing both the seniority model and a full shell model (with a single active orbit). Transitions to the double analog state and to the ground state of the residual nucleus are computed. The seniority model yields particularly simple relations among double charge exchange cross sections for nuclei within the same shell. Limitations of the seniority model and of the plane-wave impulse approximation are discussed as well as extensions to the generalized seniority scheme. Applications of the foregoing ideas to single charge exchange are also presented
International Nuclear Information System (INIS)
Hicks, S.F.; Hanly, J.M.; Hicks, S.E.; Shen, G.R.; McEllistrem, M.T.
1994-01-01
Differential elastic and inelastic scattering cross sections have been measured for neutrons incident on 204 Pb and 206 Pb at energies of 2.5, 4.6, and 8.0 MeV and total cross sections in 100-keV steps from 250 keV to 4.0 MeV. Both spherical and coupled-channels analyses have been used to interpret this large set of data, together with other cross sections extending to 8 MeV. Several purposes motivate this work. The first is to establish the dispersion-corrected mean field appropriate for these nuclei. A consistent description of the energy dependent neutron scattering potential includes a dispersion relation connecting the real and imaginary parts of the potential; the resultant potential relates the energy dependent scattering field to one representing bound single particle levels. Dispersion relations using both the single channel and coupled-channels models have been examined; both give very similar results. The second motivation is to deduce neutron and proton excitation strengths of the lowest-energy quadrupole and octupole excitations seen via neutron scattering, and to compare those strengths with similar values derived from electromagnetic exciton, heavy-ion and pion scattering. The role of target neutrons in both collective excitations was found to be enhanced compared to the proton role
Electron-impact cross sections of Ne
International Nuclear Information System (INIS)
Tsurubuchi, S.; Arakawa, K.; Kinokuni, S.; Motohashi, K.
2000-01-01
Electron-impact absolute emission cross sections were measured for the 3p→3s transitions of Ne. Excitation functions of the 3s→2p first resonance lines were measured in the energy range from the threshold to 1000 eV by a polarization-free optical method and relative cross sections were normalized to the absolute values, (41.0±5.4)x10 -19 cm 2 for the 73.6 nm line and (7.1±1.0)x10 -19 cm 2 for the 74.4 nm line, which were determined at 500 eV. The integrated level-excitation cross sections of Suzuki et al for the 1s 2 and 1s 4 levels were combined with the corresponding 3p→3s cascade cross sections obtained in this paper to give absolute emission cross sections for the resonance lines. The level-excitation cross sections of the 1s 2 and 1s 4 states in Paschen notation were determined from the threshold to 1000 eV by subtracting 3p→3s cascade cross sections from the corresponding 3s→2p emission cross sections of the resonance lines. A large cascade contribution is found in the emission cross section of the resonance lines. It is 28.5% for the 73.6 nm line and 49.6% for the 74.4 nm line at 40 eV, and 17.0 and 61.8%, respectively, at 300 eV. (author)
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.)
Bary, Ghulam; Ru, Peng; Zhang, Wei-Ning
2018-06-01
We calculate the three- and four-particle correlations of identical pions in an evolving pion gas (EPG) model with Bose–Einstein condensation. The multi-pion correlation functions in the EPG model are analyzed in different momentum intervals and compared with the experimental data for Pb–Pb collisions at \\sqrt{{s}{NN}}=2.76 {TeV}. It is found that the multi-pion correlation functions and cumulant correlation functions are sensitive to the condensation fraction of the EPG sources in the low average transverse-momentum intervals of the three and four pions. The model results of the multi-pion correlations are consistent with the experimental data in a considerable degree, which gives a source condensation fraction between 16% and 47%.
Neutron cross sections: Book of curves
International Nuclear Information System (INIS)
McLane, V.; Dunford, C.L.; Rose, P.F.
1988-01-01
Neuton Cross Sections: Book of Curves represents the fourth edition of what was previously known as BNL-325, Neutron Cross Sections, Volume 2, CURVES. Data is presented only for (i.e., intergrated) reaction cross sections (and related fission parameters) as a function of incident-neutron energy for the energy range 0.01 eV to 200 MeV. For the first time, isometric state production cross sections have been included. 11 refs., 4 figs
Evaluated cross section libraries
International Nuclear Information System (INIS)
Maqurno, B.A.
1976-01-01
The dosimetry tape (ENDF/B-IV tape 412) was issued in a general CSEWG distribution, August 1974. The pointwise cross section data file was tested with specified reference spectra. A group averaged cross section data file (620 groups based on tape 412) was tested with the above spectra and the results are presented in this report
Evidence for a backward peak in the γd→π0d cross section near the η threshold
International Nuclear Information System (INIS)
Ilieva, Y.; Berman, B.L.; Strakovsky, I.I.; Benmouna, N.; Briscoe, W.J.; Feldman, G.; Munevar, E.; Nadel-Turonski, P.; Tkabladze, A.; Kudryavtsev, A.E.; Tarasov, V.E.; Bedlinskiy, I.; Kossov, M.; Kuleshov, S.V.; Mikhailov, K.; Pivnyuk, N.; Pogorelko, O.; Pozdniakov, S.; Serov, V.S.; Stavinsky, A.; Vlassov, A.V.; Amarian, M.; Bagdasaryan, H.; Bueltmann, S.; Careccia, S.L.; Dodge, G.E.; Gavalian, G.; Guler, N.; Hyde-Wright, C.E.; Juengst, H.G.; Kalantarians, N.; Klein, A.; Kuhn, S.E.; Lachniet, J.; Niroula, M.R.; Tkachenko, S.; Weinstein, L.B.; Zhang, J.; Ambrozewicz, P.; Gonenc, A.; Moteabbed, M.; Anghinolfi, M.; Battaglieri, M.; De Vita, R.; Ricco, G.; Ripani, M.; Stoler, P.; Taiuti, M.; Asryan, G.; Egiyan, K.S.; Avakian, H.; Boiarinov, S.; Brooks, W.K.; Burkert, V.D.; Carman, D.S.; Degtyarenko, P.V.; Deur, A.; Egiyan, H.; Elouadrhiri, L.; Guo, L.; Gyurjyan, V.; Ito, M.M.; Laget, J.M.; Mecking, B.A.; Mestayer, M.D.; Niczyporuk, B.B.; Niyazov, R.A.; Nozar, M.; Sapunenko, V.; Sharabian, Y.G.; Smith, E.S.; Stepanyan, S.; Thoma, U.; Weygand, D.P.; Wolin, E.; Yegneswaran, A.; Baillie, N.; Butuceanu, C.; Funsten, H.; Griffioen, K.A.; Ball, J.P.; Collins, P.; Dugger, M.; Pasyuk, E.; Ritchie, B.G.; Baltzell, N.A.; Djalali, C.; Dzyubak, O.P.; Gothe, R.W.; Langheinrich, J.; Lu, H.; Nasseripour, R.; Strauch, S.; Tedeschi, D.J.; Tur, C.; Wood, M.H.; Zhao, Z.; Batourine, V.; Kim, W.; Park, K.; Stepanyan, S.S.; Bellis, M.; Bradford, R.; Dickson, R.; Krahn, Z.; Kuhn, J.; Meyer, C.A.; Moriya, K.; Schumacher, R.A.; Williams, M.; Biselli, A.S.; Bouchigny, S.; Guidal, M.; Jo, H.S.; MacCormick, M.; Niccolai, S.; Branford, D.; Watts, D.P.; Calarco, J.R.; Hersman, F.W.; Holtrop, M.; Zana, L.; Chen, S.; Coltharp, P.; Crede, V.; Eugenio, P.; Ostrovidov, A.I.; Stokes, B.E.; Cole, P.L.; Crabb, D.; Pierce, J.; Prok, Y.; Smith, L.C.; De Masi, R.; Garcon, M.; Girod, F.X.; Sabatie, F.; De Sanctis, E.; Mirazita, M.; Ronchetti, F.; Rossi, P.; Donnelly, J.; Ireland, D.G.; Kellie, J.D.; Livingston, K.; McKinnon, B.; Paterson, C.; Protopopescu, D.; Rosner, G.; Doughty, D.; Fedotov, G.; Ishkhanov, B.S.; Isupov, E.L.; Mokeev, V.; Shvedunov, N.V.; Gilfoyle, G.P.; Giovanetti, K.L.; Niculescu, G.; Niculescu, I.; Goetz, J.T.; Hafidi, K.; Hakobyan, R.S.; Klein, F.J.; Sober, D.I.; Hicks, K.; Hleiqawi, I.; Mibe, T.; Jenkins, D.; Joo, K.; Markov, N.; Ungaro, M.; Zhao, B.; Khandaker, M.; Salgado, C.; Kramer, L.H.; Raue, B.A.; Kubarovsky, V.; Lawrence, D.; Miskimen, R.; Morrow, S.A.; Mutchler, G.S.; Osipenko, M.; Price, J.W.; Santoro, J.P.; Vineyard, M.F.
2010-01-01
High-quality cross sections for the reaction γd→π 0 d have been measured using the CLAS at Jefferson Lab over a wide energy range near and above the η-meson photoproduction threshold. At backward c.m. angles for the outgoing pions, we observe a resonance-like structure near E γ =700 MeV. Our model analysis shows that it can be explained by η excitation in the intermediate state. The effect is the result of the contribution of the N(1535)S 11 -resonance to the amplitudes of the subprocesses occurring between the two nucleons and of a two-step process in which the excitation of an intermediate η-meson dominates. (orig.)
Observation of a backward peak in the gamma d ---> pi0 d cross- section near the eta threshold
Energy Technology Data Exchange (ETDEWEB)
Yordanka Ilieva; Barry Berman; Alexander Kudryavtsev; I.I. Strakovsky; V.E. Tarasov; Moscov Amaryan; Pawel Ambrozewicz; Marco Anghinolfi; G. Asryan; Harutyun Avakian; Hovhannes Baghdasaryan; Nathan Baillie; Jacques Ball; Nathan Baltzell; V. Batourine; Marco Battaglieri; Ivan Bedlinski; Ivan Bedlinskiy; Matthew Bellis; Nawal Benmouna; Angela Biselli; Sylvain Bouchigny; Sergey Boyarinov; Robert Bradford; Derek Branford; William Briscoe; William Brooks; Stephen Bueltmann; Volker Burkert; Cornel Butuceanu; John Calarco; Sharon Careccia; Daniel Carman; Shifeng Chen; Philip Cole; Patrick Collins; Philip Coltharp; Donald Crabb; Volker Crede; R. De Masi; Enzo De Sanctis; Raffaella De Vita; Pavel Degtiarenko; Alexandre Deur; Richard Dickson; Chaden Djalali; Gail Dodge; Joseph Donnelly; David Doughty; Michael Dugger; Oleksandr Dzyubak; Hovanes Egiyan; Kim Egiyan; Latifa Elouadrhiri; Paul Eugenio; Gleb Fedotov; Gerald Feldman; Herbert Funsten; Michel Garcon; Gagik Gavalian; Gerard Gilfoyle; Kevin Giovanetti; Francois-Xavier Girod; John Goetz; Atilla Gonenc; Ralf Gothe; Keith Griffioen; Michel Guidal; Nevzat Guler; Lei Guo; Vardan Gyurjyan; Kawtar Hafidi; Rafael Hakobyan; F. Hersman; Kenneth Hicks; Ishaq Hleiqawi; Maurik Holtrop; Charles Hyde; Charles Hyde-Wright; David Ireland; Boris Ishkhanov; Eugeny Isupov; Mark Ito; David Jenkins; Hyon-Suk Jo; Kyungseon Joo; Henry Juengst; Narbe Kalantarians; James Kellie; Mahbubul Khandaker; Wooyoung Kim; Andreas Klein; Franz Klein; Mikhail Kossov; Zebulun Krahn; Laird Kramer; V. Kubarovsky; Joachim Kuhn; Sebastian Kuhn; Sergey Kuleshov; Jeff Lachniet; Jean Laget; Jorn Langheinrich; David Lawrence; Kenneth Livingston; Haiyun Lu; Marion MacCormick; Nikolai Markov; Bryan McKinnon; Bernhard Mecking; Mac Mestayer; Curtis Meyer; Tsutomu Mibe; Konstantin Mikhaylov; Marco Mirazita; Rory Miskimen; Viktor Mokeev; Kei Moriya; Steven Morrow; M. Moteabbed; E. Munevar; Gordon Mutchler; Pawel Nadel-Turonski; Rakhsha Nasseripour; Silvia Niccolai; Gabriel Niculescu; Maria-Ioana Niculescu; Bogdan Niczyporuk; Megh Niroula; Rustam Niyazov; Mina Nozar; Mikhail Osipenko; Alexander Ostrovidov; K. Park; Evgueni Pasyuk; Craig Paterson; Joshua Pierce; Nikolay Pivnyuk; Oleg Pogorelko; S. Pozdniakov; John Price; Yelena Prok; Dan Protopopescu; Brian Raue; Giovanni Ricco; Marco Ripani; Barry Ritchie; Federico Ronchetti; Guenther Rosner; Patrizia Rossi; Franck Sabatie; Carlos Salgado; Joseph Santoro; Vladimir Sapunenko; Reinhard Schumacher; Vladimir Serov; Youri Sharabian; Nikolay Shvedunov; Elton Smith; Lee Smith; Daniel Sober; Aleksey Stavinskiy; Samuel Stepanyan; Stepan Stepanyan; Burnham Stokes; Paul Stoler; Steffen Strauch; Mauro Taiuti; David Tedeschi; Ulrike Thoma; Avtandil Tkabladze; Svyatoslav Tkachenko; Clarisse Tur; Maurizio Ungaro; Michael Vineyard; Alexander Vlassov; Lawrence Weinstein; Dennis Weygand; M. Williams; Elliott Wolin; Michael Wood; Amrit Yegneswaran; Lorenzo Zana; Jixie Zhang; Bo Zhao; Zhiwen Zhao
2007-05-14
High-quality cross sections for the reaction gamma+d->pi^0+d have been measured using the CLAS at Jefferson Lab over a wide energy range near and above the eta-meson photoproduction threshold. At backward c.m. angles for the outgoing pions, we observe a resonance-like structure near E_gamma=700 MeV. Our model analysis shows that it can be explained by eta excitation in the intermediate state. The effect is the result of the contribution of the N(1535)S_11 resonance to the amplitudes of the subprocesses occurring between the two nucleons and of a two-step process in which the excitation of an intermediate eta meson dominates.
In-medium modification of pion-pairs on deuterium
Energy Technology Data Exchange (ETDEWEB)
Lugert, Stefan
2007-11-23
In this thesis the quasi free photo production of pion pairs on bound nucleons {gamma}+A{yields} {pi}{pi}(A-1)+N is analyzed for liquid Deuterium. A pioneering experiment with a photon beam was performed by the TAPS collaboration at the accelerator facility MAMI-B in Mainz in 1999. This measurement observed an invariant mass shift of the isoscalar {pi}{sup 0}{pi}{sup 0} channel with increasing atomic number as well. 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. In this experiment, the TAPS detector was used as a forward wall in combination with the Crystal Ball detector to achieve almost the complete 4{pi} solid angle coverage for particle detection at the MAMI accelerator facility. The installation of the experimental setup started at the end of 2003. The new readout electronics for the BaF{sub 2} crystals was used for the first time. Between June 2004 and April 2005 measurements on several targets were performed, including the lD{sub 2} data which has been analyzed in this work. The analysis of the Deuterium data is an essential contribution to understanding the ongoing processes for two reasons. Firstly, there is the possibility to compare the solid targets and Hydrogen to the lightest nucleus having Fermi motion included but the lowest possible nuclear volume, the Deuterium. For the second reason, there are no data for the mass differential cross section on the neutron available for the mentioned channels. Analyzing the Deuterium data and subtracting the published proton data, the cross section on the neutron gets accessible. An essential question for the theory is whether the cross section on neutron and proton are the same or how much they differ in the relevant energy regime. To determine the absolute cross section, the efficiency of the detector system is required. To provide this efficiency, I also
In-medium modification of pion-pairs on deuterium
International Nuclear Information System (INIS)
Lugert, Stefan
2007-01-01
In this thesis the quasi free photo production of pion pairs on bound nucleons γ+A→ ππ(A-1)+N is analyzed for liquid Deuterium. A pioneering experiment with a photon beam was performed by the TAPS collaboration at the accelerator facility MAMI-B in Mainz in 1999. This measurement observed an invariant mass shift of the isoscalar π 0 π 0 channel with increasing atomic number as well. 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. In this experiment, the TAPS detector was used as a forward wall in combination with the Crystal Ball detector to achieve almost the complete 4π solid angle coverage for particle detection at the MAMI accelerator facility. The installation of the experimental setup started at the end of 2003. The new readout electronics for the BaF 2 crystals was used for the first time. Between June 2004 and April 2005 measurements on several targets were performed, including the lD 2 data which has been analyzed in this work. The analysis of the Deuterium data is an essential contribution to understanding the ongoing processes for two reasons. Firstly, there is the possibility to compare the solid targets and Hydrogen to the lightest nucleus having Fermi motion included but the lowest possible nuclear volume, the Deuterium. For the second reason, there are no data for the mass differential cross section on the neutron available for the mentioned channels. Analyzing the Deuterium data and subtracting the published proton data, the cross section on the neutron gets accessible. An essential question for the theory is whether the cross section on neutron and proton are the same or how much they differ in the relevant energy regime. To determine the absolute cross section, the efficiency of the detector system is required. To provide this efficiency, I also developed the MonteCarlo simulation using a
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
Energy Technology Data Exchange (ETDEWEB)
Chatrchyan, Serguei; et al.
2013-07-16
The Lambda(b) differential production cross section and the cross section ratio anti-Lambda(b)/Lambda(b) are measured as functions of transverse momentum pt(Lambda(b)) and rapidity abs(y(Lambda(b))) in pp collisions at sqrt(s) = 7 TeV using data collected by the CMS experiment at the LHC. The measurements are based on Lambda(b) decays reconstructed in the exclusive final state J/Psi Lambda, with the subsequent decays J/Psi to an opposite-sign muon pair and Lambda to proton pion, using a data sample corresponding to an integrated luminosity of 1.9 inverse femtobarns. The product of the cross section times the branching ratio for Lambda(b) to J/Psi Lambda versus pt(Lambda(b)) falls faster than that of b mesons. The measured value of the cross section times the branching ratio for pt(Lambda(b)) > 10 GeV and abs(y(Lambda(b))) < 2.0 is 1.06 +/- 0.06 +/- 0.12 nb, and the integrated cross section ratio for anti-Lambda(b)/Lambda(b) is 1.02 +/- 0.07 +/- 0.09, where the uncertainties are statistical and systematic, respectively.
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; Hörmann, Natascha; Hrubec, Josef; Jeitler, Manfred; Kiesenhofer, Wolfgang; Knünz, Valentin; Krammer, Manfred; Liko, Dietrich; Mikulec, Ivan; Pernicka, Manfred; Rahbaran, Babak; Rohringer, Christine; Rohringer, Herbert; Schöfbeck, Robert; Strauss, Josef; Taurok, Anton; Wagner, Philipp; Waltenberger, Wolfgang; Walzel, Gerhard; Widl, Edmund; Wulz, Claudia-Elisabeth; Mossolov, Vladimir; Shumeiko, Nikolai; Suarez Gonzalez, Juan; Bansal, Sunil; Cornelis, Tom; De Wolf, Eddi A; Janssen, Xavier; Luyckx, Sten; Maes, Thomas; Mucibello, Luca; Ochesanu, Silvia; Roland, Benoit; Rougny, Romain; Selvaggi, Michele; Staykova, Zlatka; Van Haevermaet, Hans; Van Mechelen, Pierre; Van Remortel, Nick; Van Spilbeeck, Alex; Blekman, Freya; Blyweert, Stijn; D'Hondt, Jorgen; Gonzalez Suarez, Rebeca; Kalogeropoulos, Alexis; Maes, Michael; Olbrechts, Annik; Van Doninck, Walter; Van Mulders, Petra; Van Onsem, Gerrit Patrick; Villella, Ilaria; Charaf, Otman; Clerbaux, Barbara; De Lentdecker, Gilles; Dero, Vincent; Gay, Arnaud; Hreus, Tomas; Léonard, Alexandre; Marage, Pierre Edouard; Reis, Thomas; Thomas, Laurent; Vander Velde, Catherine; Vanlaer, Pascal; Wang, Jian; Adler, Volker; Beernaert, Kelly; Cimmino, Anna; Costantini, Silvia; Garcia, Guillaume; Grunewald, Martin; Klein, Benjamin; Lellouch, Jérémie; Marinov, Andrey; Mccartin, Joseph; Ocampo Rios, Alberto Andres; Ryckbosch, Dirk; Strobbe, Nadja; Thyssen, Filip; Tytgat, Michael; Vanelderen, Lukas; Verwilligen, Piet; Walsh, Sinead; Yazgan, Efe; Zaganidis, Nicolas; Basegmez, Suzan; Bruno, Giacomo; Castello, Roberto; Ceard, Ludivine; Delaere, Christophe; Du Pree, Tristan; Favart, Denis; Forthomme, Laurent; Giammanco, Andrea; Hollar, Jonathan; Lemaitre, Vincent; Liao, Junhui; Militaru, Otilia; Nuttens, Claude; Pagano, Davide; Pin, Arnaud; Piotrzkowski, Krzysztof; Schul, Nicolas; Vizan Garcia, Jesus Manuel; Beliy, Nikita; Caebergs, Thierry; Daubie, Evelyne; Hammad, Gregory Habib; Alves, Gilvan; Correa Martins Junior, Marcos; De Jesus Damiao, Dilson; Martins, Thiago; Pol, Maria Elena; Henrique Gomes E Souza, Moacyr; Aldá Júnior, Walter Luiz; Carvalho, Wagner; Custódio, Analu; Melo Da Costa, Eliza; De Oliveira Martins, Carley; Fonseca De Souza, Sandro; Matos Figueiredo, Diego; Mundim, Luiz; Nogima, Helio; Oguri, Vitor; Prado Da Silva, Wanda Lucia; Santoro, Alberto; Soares Jorge, Luana; Sznajder, Andre; Bernardes, Cesar Augusto; De Almeida Dias, Flavia; Tomei, Thiago; De Moraes Gregores, Eduardo; Lagana, Caio; Da Cunha Marinho, Franciole; Mercadante, Pedro G; Novaes, Sergio F; Padula, Sandra; Genchev, Vladimir; Iaydjiev, Plamen; Piperov, Stefan; Rodozov, Mircho; Stoykova, Stefka; Sultanov, Georgi; Tcholakov, Vanio; Trayanov, Rumen; Vutova, Mariana; Dimitrov, Anton; Hadjiiska, Roumyana; Kozhuharov, Venelin; Litov, Leander; 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, Xianyou; Wang, Zheng; Xiao, Hong; Xu, Ming; Zang, Jingjing; Zhang, Zhen; Asawatangtrakuldee, Chayanit; Ban, Yong; Guo, Shuang; Guo, Yifei; Li, Wenbo; Liu, Shuai; Mao, Yajun; Qian, Si-Jin; Teng, Haiyun; Wang, Siguang; Zhu, Bo; Zou, Wei; Avila, Carlos; Gomez, Juan Pablo; Gomez Moreno, Bernardo; Osorio Oliveros, Andres Felipe; Sanabria, Juan Carlos; Godinovic, Nikola; Lelas, Damir; Plestina, Roko; Polic, Dunja; Puljak, Ivica; Antunovic, Zeljko; Kovac, Marko; Brigljevic, Vuko; Duric, Senka; Kadija, Kreso; Luetic, Jelena; Morovic, Srecko; Attikis, Alexandros; Galanti, Mario; Mavromanolakis, Georgios; Mousa, Jehad; Nicolaou, Charalambos; Ptochos, Fotios; Razis, Panos A; Finger, Miroslav; Finger Jr, Michael; Assran, Yasser; Elgammal, Sherif; Ellithi Kamel, Ali; Khalil, Shaaban; Mahmoud, Mohammed; Radi, Amr; Kadastik, Mario; Müntel, Mait; Raidal, Martti; Rebane, Liis; Tiko, Andres; Azzolini, Virginia; Eerola, Paula; Fedi, Giacomo; Voutilainen, Mikko; 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; Peltola, Timo; Tuominen, Eija; Tuominiemi, Jorma; Tuovinen, Esa; Ungaro, Donatella; Wendland, Lauri; Banzuzi, Kukka; Korpela, Arja; Tuuva, Tuure; Besancon, Marc; Choudhury, Somnath; Dejardin, Marc; Denegri, Daniel; Fabbro, Bernard; Faure, Jean-Louis; Ferri, Federico; Ganjour, Serguei; Givernaud, Alain; Gras, Philippe; Hamel de Monchenault, Gautier; Jarry, Patrick; Locci, Elizabeth; Malcles, Julie; Millischer, Laurent; Nayak, Aruna; Rander, John; Rosowsky, André; Shreyber, Irina; Titov, Maksym; Baffioni, Stephanie; Beaudette, Florian; Benhabib, Lamia; Bianchini, Lorenzo; Bluj, Michal; Broutin, Clementine; Busson, Philippe; Charlot, Claude; Daci, Nadir; Dahms, Torsten; Dobrzynski, Ludwik; Granier de Cassagnac, Raphael; Haguenauer, Maurice; Miné, Philippe; Mironov, Camelia; Ochando, Christophe; Paganini, Pascal; Sabes, David; Salerno, Roberto; Sirois, Yves; Veelken, Christian; 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; Juillot, Pierre; Karim, Mehdi; Le Bihan, Anne-Catherine; Van Hove, Pierre; Fassi, Farida; Mercier, Damien; Beauceron, Stephanie; Beaupere, Nicolas; Bondu, Olivier; Boudoul, Gaelle; Brun, Hugues; Chasserat, Julien; Chierici, Roberto; Contardo, Didier; Depasse, Pierre; El Mamouni, Houmani; Fay, Jean; Gascon, Susan; Gouzevitch, Maxime; Ille, Bernard; Kurca, Tibor; Lethuillier, Morgan; Mirabito, Laurent; Perries, Stephane; Sordini, Viola; Tosi, Silvano; Tschudi, Yohann; Verdier, Patrice; Viret, Sébastien; Tsamalaidze, Zviad; Anagnostou, Georgios; Beranek, Sarah; Edelhoff, Matthias; Feld, Lutz; Heracleous, Natalie; Hindrichs, Otto; Jussen, Ruediger; Klein, Katja; Merz, Jennifer; Ostapchuk, Andrey; Perieanu, Adrian; Raupach, Frank; Sammet, Jan; Schael, Stefan; Sprenger, Daniel; Weber, Hendrik; Wittmer, Bruno; Zhukov, Valery; Ata, Metin; Caudron, Julien; Dietz-Laursonn, Erik; Erdmann, Martin; Güth, Andreas; Hebbeker, Thomas; Heidemann, Carsten; Hoepfner, Kerstin; Klingebiel, Dennis; Kreuzer, Peter; Lingemann, Joschka; Magass, Carsten; Merschmeyer, Markus; Meyer, Arnd; Olschewski, Mark; Papacz, Paul; Pieta, Holger; Reithler, Hans; Schmitz, Stefan Antonius; Sonnenschein, Lars; Steggemann, Jan; Teyssier, Daniel; Weber, Martin; Bontenackels, Michael; Cherepanov, Vladimir; Davids, Martina; Flügge, Günter; Geenen, Heiko; Geisler, Matthias; Haj Ahmad, Wael; Hoehle, Felix; Kargoll, Bastian; Kress, Thomas; Kuessel, Yvonne; Linn, Alexander; Nowack, Andreas; Perchalla, Lars; Pooth, Oliver; Rennefeld, Jörg; Sauerland, Philip; Stahl, Achim; Aldaya Martin, Maria; Behr, Joerg; Behrenhoff, Wolf; Behrens, Ulf; Bergholz, Matthias; Bethani, Agni; Borras, Kerstin; Burgmeier, Armin; Cakir, Altan; Calligaris, Luigi; Campbell, Alan; Castro, Elena; Costanza, Francesco; Dammann, Dirk; Eckerlin, Guenter; Eckstein, Doris; Fischer, David; Flucke, Gero; Geiser, Achim; Glushkov, Ivan; Habib, Shiraz; Hauk, Johannes; Jung, Hannes; Kasemann, Matthias; Katsas, Panagiotis; Kleinwort, Claus; Kluge, Hannelies; Knutsson, Albert; Krämer, Mira; Krücker, Dirk; Kuznetsova, Ekaterina; Lange, Wolfgang; Lohmann, Wolfgang; Lutz, Benjamin; Mankel, Rainer; Marfin, Ihar; Marienfeld, Markus; Melzer-Pellmann, Isabell-Alissandra; Meyer, Andreas Bernhard; Mnich, Joachim; Mussgiller, Andreas; Naumann-Emme, Sebastian; Olzem, Jan; Perrey, Hanno; Petrukhin, Alexey; Pitzl, Daniel; Raspereza, Alexei; Ribeiro Cipriano, Pedro M; Riedl, Caroline; Rosin, Michele; Salfeld-Nebgen, Jakob; Schmidt, Ringo; Schoerner-Sadenius, Thomas; Sen, Niladri; Spiridonov, Alexander; Stein, Matthias; Walsh, Roberval; Wissing, Christoph; Autermann, Christian; Blobel, Volker; Bobrovskyi, Sergei; Draeger, Jula; Enderle, Holger; Erfle, Joachim; Gebbert, Ulla; Görner, Martin; Hermanns, Thomas; Höing, Rebekka Sophie; Kaschube, Kolja; Kaussen, Gordon; Kirschenmann, Henning; Klanner, Robert; Lange, Jörn; Mura, Benedikt; Nowak, Friederike; Peiffer, Thomas; Pietsch, Niklas; Sander, Christian; Schettler, Hannes; Schleper, Peter; Schlieckau, Eike; Schmidt, Alexander; Schröder, Matthias; Schum, Torben; Stadie, Hartmut; Steinbrück, Georg; Thomsen, Jan; Barth, Christian; Berger, Joram; Chwalek, Thorsten; De Boer, Wim; Dierlamm, Alexander; Feindt, Michael; Guthoff, Moritz; Hackstein, Christoph; Hartmann, Frank; Heinrich, Michael; Held, Hauke; Hoffmann, Karl-Heinz; Honc, Simon; Katkov, Igor; Komaragiri, Jyothsna Rani; Martschei, Daniel; Mueller, Steffen; Müller, Thomas; Niegel, Martin; Nürnberg, Andreas; Oberst, Oliver; Oehler, Andreas; Ott, Jochen; Quast, Gunter; Rabbertz, Klaus; Ratnikov, Fedor; Ratnikova, Natalia; Röcker, Steffen; Scheurer, Armin; Schilling, Frank-Peter; Schott, Gregory; Simonis, Hans-Jürgen; Stober, Fred-Markus Helmut; Troendle, Daniel; Ulrich, Ralf; Wagner-Kuhr, Jeannine; Weiler, Thomas; Zeise, Manuel; Daskalakis, Georgios; Geralis, Theodoros; Kesisoglou, Stilianos; Kyriakis, Aristotelis; Loukas, Demetrios; Manolakos, Ioannis; Markou, Athanasios; Markou, Christos; Mavrommatis, Charalampos; Ntomari, Eleni; Gouskos, Loukas; Mertzimekis, Theodoros; Panagiotou, Apostolos; Saoulidou, Niki; Evangelou, Ioannis; Foudas, Costas; Kokkas, Panagiotis; Manthos, Nikolaos; Papadopoulos, Ioannis; Patras, Vaios; Bencze, Gyorgy; Hajdu, Csaba; Hidas, Pàl; Horvath, Dezso; Krajczar, Krisztian; Radics, Balint; Sikler, Ferenc; Veszpremi, Viktor; Vesztergombi, Gyorgy; Beni, Noemi; Czellar, Sandor; Molnar, Jozsef; Palinkas, Jozsef; Szillasi, Zoltan; Karancsi, János; Raics, Peter; Trocsanyi, Zoltan Laszlo; Ujvari, Balazs; 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, Jasbir; Ahuja, Sudha; Bhardwaj, Ashutosh; Choudhary, Brajesh C; Kumar, Ashok; Kumar, Arun; Malhotra, Shivali; Naimuddin, Md; Ranjan, Kirti; Sharma, Varun; Shivpuri, Ram Krishen; Banerjee, Sunanda; Bhattacharya, Satyaki; Dutta, Suchandra; Gomber, Bhawna; Jain, Sandhya; Jain, Shilpi; Khurana, Raman; Sarkar, Subir; Sharan, Manoj; Abdulsalam, Abdulla; Choudhury, Rajani Kant; Dutta, Dipanwita; Kailas, Swaminathan; Kumar, Vineet; Mehta, Pourus; Mohanty, Ajit Kumar; Pant, Lalit Mohan; Shukla, Prashant; Aziz, Tariq; Ganguly, Sanmay; Guchait, Monoranjan; Maity, Manas; Majumder, Gobinda; Mazumdar, Kajari; Mohanty, Gagan Bihari; Parida, Bibhuti; Sudhakar, Katta; Wickramage, Nadeesha; Banerjee, Sudeshna; Dugad, Shashikant; Arfaei, Hessamaddin; Bakhshiansohi, Hamed; Etesami, Seyed Mohsen; Fahim, Ali; Hashemi, Majid; Hesari, Hoda; Jafari, Abideh; Khakzad, Mohsen; Mohammadi, Abdollah; Mohammadi Najafabadi, Mojtaba; Paktinat Mehdiabadi, Saeid; Safarzadeh, Batool; Zeinali, Maryam; Abbrescia, Marcello; Barbone, Lucia; Calabria, Cesare; Chhibra, Simranjit Singh; Colaleo, Anna; Creanza, Donato; De Filippis, Nicola; De Palma, Mauro; Fiore, Luigi; Iaselli, Giuseppe; Lusito, Letizia; Maggi, Giorgio; Maggi, Marcello; Marangelli, Bartolomeo; My, Salvatore; Nuzzo, Salvatore; Pacifico, Nicola; Pompili, Alexis; Pugliese, Gabriella; Selvaggi, Giovanna; Silvestris, Lucia; Singh, Gurpreet; 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; Grandi, Claudio; Guiducci, Luigi; 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; Potenza, Renato; Tricomi, Alessia; Tuve, Cristina; Barbagli, Giuseppe; Ciulli, Vitaliano; Civinini, Carlo; D'Alessandro, Raffaello; Focardi, Ettore; Frosali, Simone; Gallo, Elisabetta; Gonzi, Sandro; 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; Fiorendi, Sara; Gennai, Simone; Ghezzi, Alessio; Malvezzi, Sandra; Manzoni, Riccardo Andrea; 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; Dogangun, Oktay; Fabozzi, Francesco; Iorio, Alberto Orso Maria; Lista, Luca; Meola, Sabino; Merola, Mario; Paolucci, Pierluigi; Azzi, Patrizia; Bacchetta, Nicola; Bellan, Paolo; Bisello, Dario; Branca, Antonio; Carlin, Roberto; Checchia, Paolo; Dorigo, Tommaso; Dosselli, Umberto; Gasparini, Fabrizio; Gozzelino, Andrea; Kanishchev, Konstantin; Lacaprara, Stefano; Lazzizzera, Ignazio; Margoni, Martino; Meneguzzo, Anna Teresa; Nespolo, Massimo; Perrozzi, Luca; Pozzobon, Nicola; Ronchese, Paolo; Simonetto, Franco; Torassa, Ezio; Tosi, Mia; Vanini, Sara; Zotto, Pierluigi; Gabusi, Michele; Ratti, Sergio P; Riccardi, Cristina; Torre, Paola; Vitulo, Paolo; Biasini, Maurizio; Bilei, Gian Mario; Fanò, Livio; Lariccia, Paolo; Lucaroni, Andrea; Mantovani, Giancarlo; Menichelli, Mauro; Nappi, Aniello; Romeo, Francesco; Saha, Anirban; Santocchia, Attilio; Taroni, Silvia; Azzurri, Paolo; Bagliesi, Giuseppe; 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; Palmonari, Francesco; Rizzi, Andrea; Serban, Alin Titus; Spagnolo, Paolo; Squillacioti, Paola; Tenchini, Roberto; Tonelli, Guido; Venturi, Andrea; Verdini, Piero Giorgio; Barone, Luciano; Cavallari, Francesca; Del Re, Daniele; Diemoz, Marcella; Grassi, Marco; Longo, Egidio; Meridiani, Paolo; Micheli, Francesco; Nourbakhsh, Shervin; Organtini, Giovanni; Paramatti, Riccardo; Rahatlou, Shahram; Sigamani, Michael; Soffi, Livia; Amapane, Nicola; Arcidiacono, Roberta; Argiro, Stefano; Arneodo, Michele; Biino, Cristina; Botta, Cristina; Cartiglia, Nicolo; Costa, Marco; De Remigis, Paolo; Demaria, Natale; Graziano, Alberto; Mariotti, Chiara; Maselli, Silvia; Migliore, Ernesto; Monaco, Vincenzo; Musich, Marco; Obertino, Maria Margherita; Pastrone, Nadia; Pelliccioni, Mario; Potenza, Alberto; Romero, Alessandra; Ruspa, Marta; Sacchi, Roberto; Solano, Ada; Staiano, Amedeo; Vilela Pereira, Antonio; Belforte, Stefano; Cossutti, Fabio; Della Ricca, Giuseppe; Gobbo, Benigno; Marone, Matteo; Montanino, Damiana; Penzo, Aldo; Schizzi, Andrea; Heo, Seong Gu; Kim, Tae Yeon; Nam, Soon-Kwon; Chang, Sunghyun; Chung, Jin Hyuk; Kim, Dong Hee; Kim, Gui Nyun; Kong, Dae Jung; Park, Hyangkyu; Ro, Sang-Ryul; Son, Dong-Chul; Son, Taejin; Kim, Jae Yool; Kim, Zero Jaeho; Song, Sanghyeon; Jo, Hyun Yong; Choi, Suyong; Gyun, Dooyeon; Hong, Byung-Sik; Jo, Mihee; Kim, Hyunchul; Kim, Tae Jeong; Lee, Kyong Sei; Moon, Dong Ho; Park, Sung Keun; Seo, Eunsung; Choi, Minkyoo; Kang, Seokon; Kim, Hyunyong; Kim, Ji Hyun; Park, Chawon; Park, Inkyu; Park, Sangnam; Ryu, Geonmo; Cho, Yongjin; Choi, Young-Il; Choi, Young Kyu; Goh, Junghwan; Kim, Min Suk; Kwon, Eunhyang; Lee, Byounghoon; Lee, Jongseok; Lee, Sungeun; Seo, Hyunkwan; Yu, Intae; Bilinskas, Mykolas Jurgis; Grigelionis, Ignas; Janulis, Mindaugas; Juodagalvis, Andrius; Castilla-Valdez, Heriberto; De La Cruz-Burelo, Eduard; Heredia-de La Cruz, Ivan; Lopez-Fernandez, Ricardo; Magaña Villalba, Ricardo; Martínez-Ortega, Jorge; 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; Bell, Alan James; Butler, Philip H; Doesburg, Robert; Reucroft, Steve; Silverwood, Hamish; Ahmad, Muhammad; Asghar, Muhammad Irfan; Hoorani, Hafeez R; Khalid, Shoaib; Khan, Wajid Ali; Khurshid, Taimoor; Qazi, Shamona; Shah, Mehar Ali; Shoaib, Muhammad; Brona, Grzegorz; Bunkowski, Karol; Cwiok, Mikolaj; Dominik, Wojciech; Doroba, Krzysztof; Kalinowski, Artur; Konecki, Marcin; Krolikowski, Jan; Bialkowska, Helena; Boimska, Bozena; 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; Seixas, Joao; Varela, Joao; Vischia, Pietro; Belotelov, Ivan; Bunin, Pavel; Gavrilenko, Mikhail; Golutvin, Igor; Gorbunov, Ilya; Kamenev, Alexey; Karjavin, Vladimir; Kozlov, Guennady; Lanev, Alexander; Malakhov, Alexander; Moisenz, Petr; Palichik, Vladimir; Perelygin, Victor; Shmatov, Sergey; Smirnov, Vitaly; Volodko, Anton; Zarubin, Anatoli; Evstyukhin, Sergey; 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; Tlisov, Danila; Toropin, Alexander; Epshteyn, Vladimir; Erofeeva, Maria; Gavrilov, Vladimir; Kossov, Mikhail; Lychkovskaya, Natalia; Popov, Vladimir; Safronov, Grigory; Semenov, Sergey; Stolin, Viatcheslav; Vlasov, Evgueni; Zhokin, Alexander; Belyaev, Andrey; Boos, Edouard; Dubinin, Mikhail; Dudko, Lev; Ershov, Alexander; Gribushin, Andrey; Klyukhin, Vyacheslav; Kodolova, Olga; Lokhtin, Igor; Markina, Anastasia; Obraztsov, Stepan; Perfilov, Maxim; Petrushanko, Sergey; Popov, Andrey; Sarycheva, Ludmila; Savrin, Viktor; Snigirev, Alexander; Andreev, Vladimir; Azarkin, Maksim; Dremin, Igor; Kirakosyan, Martin; Leonidov, Andrey; Mesyats, Gennady; Rusakov, Sergey V; Vinogradov, Alexey; Azhgirey, Igor; Bayshev, Igor; Bitioukov, Sergei; Grishin, Viatcheslav; Kachanov, Vassili; Konstantinov, Dmitri; Korablev, Andrey; Krychkine, Victor; Petrov, Vladimir; Ryutin, Roman; Sobol, Andrei; Tourtchanovitch, Leonid; Troshin, Sergey; Tyurin, Nikolay; Uzunian, Andrey; Volkov, Alexey; Adzic, Petar; Djordjevic, Milos; Ekmedzic, Marko; Krpic, Dragomir; Milosevic, Jovan; Aguilar-Benitez, Manuel; Alcaraz Maestre, Juan; Arce, Pedro; Battilana, Carlo; Calvo, Enrique; 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; Quintario Olmeda, Adrián; 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; Piedra Gomez, Jonatan; 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; 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; Bernet, Colin; Bianchi, Giovanni; Bloch, Philippe; Bocci, Andrea; Bonato, Alessio; Breuker, Horst; Camporesi, Tiziano; Cerminara, Gianluca; Christiansen, Tim; Coarasa Perez, Jose Antonio; D'Enterria, David; Dabrowski, Anne; De Roeck, Albert; Di Guida, Salvatore; Dobson, Marc; Dupont-Sagorin, Niels; Elliott-Peisert, Anna; Frisch, Benjamin; Funk, Wolfgang; Georgiou, Georgios; Giffels, Manuel; Gigi, Dominique; Gill, Karl; Giordano, Domenico; Giunta, Marina; Glege, Frank; Gomez-Reino Garrido, Robert; Govoni, Pietro; Gowdy, Stephen; Guida, Roberto; Hansen, Magnus; Harris, Philip; Hartl, Christian; Harvey, John; Hegner, Benedikt; Hinzmann, Andreas; Innocente, Vincenzo; Janot, Patrick; Kaadze, Ketino; Karavakis, Edward; Kousouris, Konstantinos; Lecoq, Paul; Lee, Yen-Jie; Lenzi, Piergiulio; Lourenco, Carlos; Maki, Tuula; Malberti, Martina; Malgeri, Luca; Mannelli, Marcello; Masetti, Lorenzo; Meijers, Frans; Mersi, Stefano; Meschi, Emilio; Moser, Roland; Mozer, Matthias Ulrich; Mulders, Martijn; Musella, Pasquale; Nesvold, Erik; Nguyen, Matthew; Orimoto, Toyoko; Orsini, Luciano; Palencia Cortezon, Enrique; Perez, Emmanuelle; Petrilli, Achille; Pfeiffer, Andreas; Pierini, Maurizio; Pimiä, Martti; Piparo, Danilo; Polese, Giovanni; Quertenmont, Loic; Racz, Attila; Reece, William; Rodrigues Antunes, Joao; Rolandi, Gigi; Rommerskirchen, Tanja; Rovelli, Chiara; Rovere, Marco; Sakulin, Hannes; Santanastasio, Francesco; Schäfer, Christoph; Schwick, Christoph; Segoni, Ilaria; Sekmen, Sezen; Sharma, Archana; Siegrist, Patrice; Silva, Pedro; Simon, Michal; Sphicas, Paraskevas; Spiga, Daniele; Spiropulu, Maria; Stoye, Markus; Tsirou, Andromachi; Veres, Gabor Istvan; Vlimant, Jean-Roch; Wöhri, Hermine Katharina; Worm, Steven; 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; Bäni, Lukas; Bortignon, Pierluigi; Buchmann, Marco-Andrea; Casal, Bruno; Chanon, Nicolas; Chen, Zhiling; Deisher, Amanda; Dissertori, Günther; Dittmar, Michael; Dünser, Marc; Eugster, Jürg; Freudenreich, Klaus; Grab, Christoph; Hits, Dmitry; Lecomte, Pierre; Lustermann, Werner; Martinez Ruiz del Arbol, Pablo; Mohr, Niklas; Moortgat, Filip; Nägeli, Christoph; Nef, Pascal; Nessi-Tedaldi, Francesca; Pandolfi, Francesco; Pape, Luc; Pauss, Felicitas; Peruzzi, Marco; Ronga, Frederic Jean; Rossini, Marco; Sala, Leonardo; Sanchez, Ann - Karin; Starodumov, Andrei; Stieger, Benjamin; Takahashi, Maiko; Tauscher, Ludwig; Thea, Alessandro; Theofilatos, Konstantinos; Treille, Daniel; Urscheler, Christina; Wallny, Rainer; Weber, Hannsjoerg Artur; Wehrli, Lukas; Aguilo, Ernest; Amsler, Claude; Chiochia, Vincenzo; De Visscher, Simon; Favaro, Carlotta; Ivova Rikova, Mirena; Millan Mejias, Barbara; Otiougova, Polina; Robmann, Peter; Snoek, Hella; Tupputi, Salvatore; Verzetti, Mauro; Chang, Yuan-Hann; Chen, Kuan-Hsin; Kuo, Chia-Ming; Li, Syue-Wei; Lin, Willis; Liu, Zong-Kai; Lu, Yun-Ju; Mekterovic, Darko; Singh, Anil; Volpe, Roberta; Yu, Shin-Shan; Bartalini, Paolo; Chang, Paoti; Chang, You-Hao; Chang, Yu-Wei; Chao, Yuan; Chen, Kai-Feng; Dietz, Charles; Grundler, Ulysses; Hou, George Wei-Shu; Hsiung, Yee; Kao, Kai-Yi; Lei, Yeong-Jyi; Lu, Rong-Shyang; Majumder, Devdatta; Petrakou, Eleni; Shi, Xin; Shiu, Jing-Ge; Tzeng, Yeng-Ming; Wan, Xia; Wang, Minzu; Adiguzel, Aytul; Bakirci, Mustafa Numan; Cerci, Salim; Dozen, Candan; Dumanoglu, Isa; Eskut, Eda; Girgis, Semiray; Gokbulut, Gul; Gurpinar, Emine; Hos, Ilknur; Kangal, Evrim Ersin; Karapinar, Guler; Kayis Topaksu, Aysel; Onengut, Gulsen; Ozdemir, Kadri; Ozturk, Sertac; Polatoz, Ayse; Sogut, Kenan; Sunar Cerci, Deniz; Tali, Bayram; Topakli, Huseyin; Vergili, Latife Nukhet; Vergili, Mehmet; Akin, Ilina Vasileva; Aliev, Takhmasib; Bilin, Bugra; Bilmis, Selcuk; Deniz, Muhammed; Gamsizkan, Halil; Guler, Ali Murat; Ocalan, Kadir; Ozpineci, Altug; Serin, Meltem; Sever, Ramazan; Surat, Ugur Emrah; Yalvac, Metin; Yildirim, Eda; Zeyrek, Mehmet; Gülmez, Erhan; Isildak, Bora; Kaya, Mithat; Kaya, Ozlem; Ozkorucuklu, Suat; Sonmez, Nasuf; Cankocak, Kerem; Levchuk, Leonid; Bostock, Francis; Brooke, James John; Clement, Emyr; Cussans, David; Flacher, Henning; Frazier, Robert; Goldstein, Joel; Grimes, Mark; Heath, Greg P; Heath, Helen F; Kreczko, Lukasz; Metson, Simon; Newbold, Dave M; Nirunpong, Kachanon; Poll, Anthony; Senkin, Sergey; Smith, Vincent J; Williams, Thomas; Basso, Lorenzo; Bell, Ken W; Belyaev, Alexander; Brew, Christopher; Brown, Robert M; 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; Bainbridge, Robert; Ball, Gordon; Beuselinck, Raymond; Buchmuller, Oliver; Colling, David; Cripps, Nicholas; Cutajar, Michael; Dauncey, Paul; 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; Magnan, Anne-Marie; Marrouche, Jad; Mathias, Bryn; Nandi, Robin; Nash, Jordan; Nikitenko, Alexander; Papageorgiou, Anastasios; Pela, Joao; Pesaresi, Mark; Petridis, Konstantinos; Pioppi, Michele; Raymond, David Mark; Rogerson, Samuel; Rose, Andrew; Ryan, Matthew John; Seez, Christopher; Sharp, Peter; Sparrow, Alex; Tapper, Alexander; Vazquez Acosta, Monica; Virdee, Tejinder; Wakefield, Stuart; Wardle, Nicholas; Whyntie, Tom; Chadwick, Matthew; Cole, Joanne; Hobson, Peter R; Khan, Akram; Kyberd, Paul; Leslie, Dawn; Martin, William; Reid, Ivan; Symonds, Philip; Teodorescu, Liliana; Turner, Mark; Hatakeyama, Kenichi; Liu, Hongxuan; Scarborough, Tara; Henderson, Conor; Rumerio, Paolo; Avetisyan, Aram; Bose, Tulika; Fantasia, Cory; Heister, Arno; St John, Jason; Lawson, Philip; Lazic, Dragoslav; Rohlf, James; Sperka, David; Sulak, Lawrence; Alimena, Juliette; Bhattacharya, Saptaparna; Cutts, David; Ferapontov, Alexey; Heintz, Ulrich; Jabeen, Shabnam; Kukartsev, Gennadiy; Landsberg, Greg; Luk, Michael; Narain, Meenakshi; Nguyen, Duong; Segala, Michael; Sinthuprasith, Tutanon; Speer, Thomas; Tsang, Ka Vang; Breedon, Richard; Breto, Guillermo; Calderon De La Barca Sanchez, Manuel; Chauhan, Sushil; Chertok, Maxwell; Conway, John; Conway, Rylan; Cox, Peter Timothy; Dolen, James; Erbacher, Robin; Gardner, Michael; Houtz, Rachel; Ko, Winston; Kopecky, Alexandra; Lander, Richard; Mall, Orpheus; Miceli, Tia; Nelson, Randy; Pellett, Dave; Rutherford, Britney; Searle, Matthew; Smith, John; Squires, Michael; Tripathi, Mani; Vasquez Sierra, Ricardo; Andreev, Valeri; Cline, David; Cousins, Robert; Duris, Joseph; Erhan, Samim; Everaerts, Pieter; Farrell, Chris; Hauser, Jay; Ignatenko, Mikhail; Plager, Charles; Rakness, Gregory; Schlein, Peter; Tucker, Jordan; Valuev, Vyacheslav; Weber, Matthias; Babb, John; Clare, Robert; Dinardo, Mauro Emanuele; Ellison, John Anthony; Gary, J William; Giordano, Ferdinando; Hanson, Gail; Jeng, Geng-Yuan; Liu, Hongliang; Long, Owen Rosser; Luthra, Arun; Nguyen, Harold; Paramesvaran, Sudarshan; Sturdy, Jared; Sumowidagdo, Suharyo; Wilken, Rachel; Wimpenny, Stephen; Andrews, Warren; Branson, James G; Cerati, Giuseppe Benedetto; Cittolin, Sergio; Evans, David; Golf, Frank; Holzner, André; Kelley, Ryan; Lebourgeois, Matthew; Letts, James; Macneill, Ian; Mangano, Boris; Padhi, Sanjay; Palmer, Christopher; Petrucciani, Giovanni; Pieri, Marco; Sani, Matteo; Sharma, Vivek; Simon, Sean; Sudano, Elizabeth; Tadel, Matevz; 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; West, Christopher; Apresyan, Artur; Bornheim, Adolf; Chen, Yi; Di Marco, Emanuele; Duarte, Javier; Gataullin, Marat; Ma, Yousi; Mott, Alexander; Newman, Harvey B; Rogan, Christopher; Timciuc, Vladlen; Traczyk, Piotr; Veverka, Jan; Wilkinson, Richard; Yang, Yong; Zhu, Ren-Yuan; Akgun, Bora; Carroll, Ryan; Ferguson, Thomas; Iiyama, Yutaro; Jang, Dong Wook; Liu, Yueh-Feng; Paulini, Manfred; Vogel, Helmut; Vorobiev, Igor; Cumalat, John Perry; Drell, Brian Robert; Edelmaier, Christopher; Ford, William T; Gaz, Alessandro; Heyburn, Bernadette; Luiggi Lopez, Eduardo; Smith, James; Stenson, Kevin; Ulmer, Keith; Wagner, Stephen Robert; Agostino, Lorenzo; Alexander, James; Chatterjee, Avishek; Eggert, Nicholas; Gibbons, Lawrence Kent; Heltsley, Brian; Hopkins, Walter; Khukhunaishvili, Aleko; Kreis, Benjamin; Mirman, Nathan; Nicolas Kaufman, Gala; Patterson, Juliet Ritchie; Ryd, Anders; Salvati, Emmanuele; Sun, Werner; Teo, Wee Don; Thom, Julia; Thompson, Joshua; Vaughan, Jennifer; Weng, Yao; Winstrom, Lucas; Wittich, Peter; Winn, Dave; Abdullin, Salavat; Albrow, Michael; Anderson, Jacob; Bauerdick, Lothar AT; Beretvas, Andrew; Berryhill, Jeffrey; Bhat, Pushpalatha C; Bloch, Ingo; Burkett, Kevin; Butler, Joel Nathan; Chetluru, Vasundhara; Cheung, Harry; Chlebana, Frank; Elvira, Victor Daniel; Fisk, Ian; Freeman, Jim; Gao, Yanyan; Green, Dan; Gutsche, Oliver; Hahn, Alan; Hanlon, Jim; Harris, Robert M; Hirschauer, James; Hooberman, Benjamin; Jindariani, Sergo; Johnson, Marvin; Joshi, Umesh; Kilminster, Benjamin; Klima, Boaz; Kunori, Shuichi; Kwan, Simon; Leonidopoulos, Christos; Lincoln, Don; Lipton, Ron; Lueking, Lee; Lykken, Joseph; Maeshima, Kaori; Marraffino, John Michael; Maruyama, Sho; Mason, David; McBride, Patricia; Mishra, Kalanand; Mrenna, Stephen; Musienko, Yuri; Newman-Holmes, Catherine; O'Dell, Vivian; Prokofyev, Oleg; Sexton-Kennedy, Elizabeth; Sharma, Seema; Spalding, William J; Spiegel, Leonard; Tan, Ping; Taylor, Lucas; Tkaczyk, Slawek; Tran, Nhan Viet; 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; Das, Souvik; De Gruttola, Michele; Di Giovanni, Gian Piero; Dobur, Didar; Drozdetskiy, Alexey; Field, Richard D; Fisher, Matthew; Fu, Yu; Furic, Ivan-Kresimir; Gartner, Joseph; Hugon, Justin; Kim, Bockjoo; Konigsberg, Jacobo; Korytov, Andrey; Kropivnitskaya, Anna; Kypreos, Theodore; Low, Jia Fu; Matchev, Konstantin; Milenovic, Predrag; Mitselmakher, Guenakh; Muniz, Lana; Remington, Ronald; Rinkevicius, Aurelijus; Sellers, Paul; Skhirtladze, Nikoloz; Snowball, Matthew; Yelton, John; Zakaria, Mohammed; Gaultney, Vanessa; Lebolo, Luis Miguel; Linn, Stephan; Markowitz, Pete; Martinez, German; 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; Veeraraghavan, Venkatesh; Weinberg, Marc; Baarmand, Marc M; Dorney, Brian; Hohlmann, Marcus; Kalakhety, Himali; Vodopiyanov, Igor; Adams, Mark Raymond; Anghel, Ioana Maria; Apanasevich, Leonard; Bai, Yuting; Bazterra, Victor Eduardo; Betts, Russell Richard; Bucinskaite, Inga; Callner, Jeremy; Cavanaugh, Richard; Dragoiu, Cosmin; Evdokimov, Olga; Gauthier, Lucie; Gerber, Cecilia Elena; Hamdan, Saleh; Hofman, David Jonathan; Khalatyan, Samvel; Lacroix, Florent; Malek, Magdalena; O'Brien, Christine; Silkworth, Christopher; Strom, Derek; Varelas, Nikos; Akgun, Ugur; Albayrak, Elif Asli; Bilki, Burak; Clarida, Warren; Duru, Firdevs; Griffiths, Scott; Merlo, Jean-Pierre; Mermerkaya, Hamit; Mestvirishvili, Alexi; Moeller, Anthony; Nachtman, Jane; Newsom, Charles Ray; Norbeck, Edwin; Onel, Yasar; Ozok, Ferhat; Sen, Sercan; Tiras, Emrah; Wetzel, James; Yetkin, Taylan; Yi, Kai; Barnett, Bruce Arnold; Blumenfeld, Barry; Bolognesi, Sara; Fehling, David; Giurgiu, Gavril; Gritsan, Andrei; Guo, Zijin; Hu, Guofan; Maksimovic, Petar; Rappoccio, Salvatore; Swartz, Morris; Whitbeck, Andrew; Baringer, Philip; Bean, Alice; Benelli, Gabriele; Grachov, Oleg; Kenny Iii, Raymond Patrick; Murray, Michael; Noonan, Daniel; Sanders, Stephen; Stringer, Robert; Tinti, Gemma; Wood, Jeffrey Scott; Zhukova, Victoria; Barfuss, Anne-Fleur; Bolton, Tim; Chakaberia, Irakli; Ivanov, Andrew; Khalil, Sadia; Makouski, Mikhail; Maravin, Yurii; Shrestha, Shruti; Svintradze, Irakli; Gronberg, Jeffrey; Lange, David; Wright, Douglas; Baden, Drew; Boutemeur, Madjid; Calvert, Brian; Eno, Sarah Catherine; Gomez, Jaime; Hadley, Nicholas John; Kellogg, Richard G; Kirn, Malina; Kolberg, Ted; Lu, Ying; Marionneau, Matthieu; Mignerey, Alice; Peterman, Alison; Skuja, Andris; Temple, Jeffrey; Tonjes, Marguerite; Tonwar, Suresh C; Twedt, Elizabeth; Bauer, Gerry; Bendavid, Joshua; Busza, Wit; Butz, Erik; Cali, Ivan Amos; Chan, Matthew; Dutta, Valentina; Gomez Ceballos, Guillelmo; Goncharov, Maxim; Hahn, Kristan Allan; Kim, Yongsun; Klute, Markus; Li, Wei; 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; Velicanu, Dragos; Wenger, Edward Allen; Wolf, Roger; Wyslouch, Bolek; Xie, Si; Yang, Mingming; Yilmaz, Yetkin; Yoon, Sungho; Zanetti, Marco; Cooper, Seth; Cushman, Priscilla; Dahmes, Bryan; De Benedetti, Abraham; Franzoni, Giovanni; Gude, Alexander; Haupt, Jason; Kao, Shih-Chuan; Klapoetke, Kevin; Kubota, Yuichi; Mans, Jeremy; Pastika, Nathaniel; Rusack, Roger; Sasseville, Michael; Singovsky, Alexander; Tambe, Norbert; Turkewitz, Jared; Cremaldi, Lucien Marcus; Kroeger, Rob; Perera, Lalith; Rahmat, Rahmat; Sanders, David A; Avdeeva, Ekaterina; Bloom, Kenneth; Bose, Suvadeep; Butt, Jamila; Claes, Daniel R; Dominguez, Aaron; Eads, Michael; Jindal, Pratima; Keller, Jason; 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; Chasco, Matthew; Haley, Joseph; Nash, David; Trocino, Daniele; Wood, Darien; Zhang, Jinzhong; Anastassov, Anton; Kubik, Andrew; Mucia, Nicholas; Odell, Nathaniel; Ofierzynski, Radoslaw Adrian; Pollack, Brian; Pozdnyakov, Andrey; Schmitt, Michael Henry; Stoynev, Stoyan; Velasco, Mayda; Won, Steven; Antonelli, Louis; Berry, Douglas; Brinkerhoff, Andrew; Hildreth, Michael; Jessop, Colin; Karmgard, Daniel John; Kolb, Jeff; Lannon, Kevin; Luo, Wuming; Lynch, Sean; Marinelli, Nancy; Morse, David Michael; Pearson, Tessa; 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Panwalkar, Shruti; Park, Michael; Patel, Rishi; Rekovic, Vladimir; Richards, Alan; Robles, Jorge; Rose, Keith; Salur, Sevil; Schnetzer, Steve; Seitz, Claudia; Somalwar, Sunil; Stone, Robert; Thomas, Scott; Cerizza, Giordano; Hollingsworth, Matthew; Spanier, Stefan; Yang, Zong-Chang; York, Andrew; Eusebi, Ricardo; Flanagan, Will; Gilmore, Jason; Kamon, Teruki; Khotilovich, Vadim; Montalvo, Roy; Osipenkov, Ilya; Pakhotin, Yuriy; Perloff, Alexx; Roe, Jeffrey; Safonov, Alexei; Sakuma, Tai; Sengupta, Sinjini; Suarez, Indara; Tatarinov, Aysen; Toback, David; Akchurin, Nural; Damgov, Jordan; Dudero, Phillip Russell; Jeong, Chiyoung; Kovitanggoon, Kittikul; Lee, Sung Won; Libeiro, Terence; Roh, Youn; Volobouev, Igor; Appelt, Eric; Engh, Daniel; Florez, Carlos; Greene, Senta; Gurrola, Alfredo; Johns, Willard; Johnston, Cody; 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; Goodell, Joseph; Hirosky, Robert; Ledovskoy, Alexander; Lin, Chuanzhe; Neu, Christopher; Wood, John; Yohay, Rachel; Gollapinni, Sowjanya; Harr, Robert; Karchin, Paul Edmund; Kottachchi Kankanamge Don, Chamath; Lamichhane, Pramod; Sakharov, Alexandre; Anderson, Michael; Bachtis, Michail; Belknap, Donald; Borrello, Laura; Carlsmith, Duncan; Cepeda, Maria; Dasu, Sridhara; Gray, Lindsey; Grogg, Kira Suzanne; Grothe, Monika; Hall-Wilton, Richard; Herndon, Matthew; Hervé, Alain; Klabbers, Pamela; Klukas, Jeffrey; Lanaro, Armando; Lazaridis, Christos; Leonard, Jessica; Loveless, Richard; Mohapatra, Ajit; Ojalvo, Isabel; Pierro, Giuseppe Antonio; Ross, Ian; Savin, Alexander; Smith, Wesley H; Swanson, Joshua
2013-07-16
The Lambda(b) differential production cross section and the cross-section ratio for anti-Lambda(b)/Lambda(b) production are measured as functions of transverse momentum pt(Lambda(b)) and rapidity y(Lambda(b)) in pp collisions at sqrt(s) = 7 TeV using data collected by the CMS experiment at the LHC. The measurements are based on Lambda(b) decays reconstructed in the exclusive final state J/Psi Lambda, with the subsequent decays J/Psi to an opposite sign muon pair and Lambda to proton pion, using a data sample corresponding to an integrated luminosity of 1.9 inverse femtobarns. The product of the cross section times the branching ratio for Lambda(b) to J/Psi Lambda versus pt(Lambda(b)) falls faster than that of b mesons. The measured value of the cross section times the branching ratio for pt(Lambda(b)) > 10 GeV and abs(y(Lambda(b))) < 2.0 is 1.02 +/- 0.06 +/- 0.12 nb, and the integrated cross section ratio for anti-Lambda(b)/Lambda(b) is 1.02 +/- 0.07 +/- 0.09, where the uncertainties are statistical and sy...
Precision measurements of the e+e−→π+π−(γ) cross section with the KLOE detector
International Nuclear Information System (INIS)
Mandaglio, G.; Babusci, D.; Badoni, D.; Balwierz-Pytko, I.; Bencivenni, G.; Bini, C.; Bloise, C.; Bossi, F.; Branchini, P.; Budano, A.; Caldeira Balkeståhl, L.; Capon, G.; Ceradini, F.; Ciambrone, P.; Czerwiński, E.; Danè, E.; De Lucia, E.; De Robertis, G.; De Santis, A.; Di Domenico, A.
2014-01-01
The muon anomalous magnetic moment is one of the most precisely measured quantities in particle physics and a persistent discrepancy of about 3 σ between standard model (SM) prediction and the experimental measurement has been observed. The leading order contribution a μ hlo is actually the main source of uncertainty in the theoretical evaluation of the muon anomaly. It is obtained by a dispersion integral using the precision measurement of hadronic cross section. The KLOE experiment at the DAΦNE ϕ−factory in Frascati was the first to exploit Initial State Radiation (ISR) processes to obtain the e + e − →π + π − (γ) cross section below 1 GeV, that accounts for most (70%) of the leading order contribution to the muon anomaly. In year 2005 and 2008 the KLOE-collaboration has published two measurements of the π + π − cross section with the photon in the initial state emitted at small angle, and an independent measurement with the photon emitted at large angle was finalized in year 2011. These measurements were normalized using luminosity from Bhabha. In the last years, a new analysis of KLOE data has been performed for obtaining the pion form factor directly from the bin-by-bin π + π − γ to μ + μ − γ ratio. We present the results of this new measurement, showing the comparison with our previous measurements, and its impact on the hadronic contribution to the muon anomaly
Spectator-velocity pions from heavy ions
International Nuclear Information System (INIS)
Rasmussen, J.; Ridout, J.; Murphy, D.; Radi, H.M.A.
1982-11-01
The discussion centers on pions in the velocity regions of target and projectile, where strong spectral features appear. The topics covered include stopped-pion studies, and convoy pions in the projectile frame
Energy Technology Data Exchange (ETDEWEB)
Falk-Vairant, P; Valladas, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1961-07-01
We present briefly the available Information on the total cross sections for pion proton scattering in the energy region from 400 MeV to 1.5 GeV. We also have collected all results on total cross sections for particular channels like elastic scattering, inelastic scattering and charge exchange. Using new results on the total cross section for neutral events, we have plotted separately the cross section for elastic and for inelastic scattering in the T = 1/2 state. (authors) [French] On presente brievement les donnees connues concernant la section efficace totale pour la diffusion des mesons pi par les protons dans le domaine d'energie de 400 MeV a 1,5 GeV. On a egalement rassemble tous les resultats concernant les sections efficaces totales pour des canaux particuliers: diffusion elastique, diffusion inelastique et echange de charge. En partant des nouveaux resultats sur la section efficace pour la diffusion elastique et inelastique dans l'etat T = 1/2. (auteurs)
Nuclear Forensics and Radiochemistry: Cross Sections
Energy Technology Data Exchange (ETDEWEB)
Rundberg, Robert S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2017-11-08
The neutron activation of components in a nuclear device can provide useful signatures of weapon design or sophistication. This lecture will cover some of the basics of neutron reaction cross sections. Nuclear reactor cross sections will also be presented to illustrate the complexity of convolving neutron energy spectra with nuclear excitation functions to calculate useful effective reactor cross sections. Deficiencies in the nuclear database will be discussed along with tools available at Los Alamos to provide new neutron cross section data.
Differential Top Cross-section Measurements
Fenton, Michael James; The ATLAS collaboration
2017-01-01
The top quark is the heaviest known fundamental particle. The measurement of the differential top-quark pair production cross-section provides a stringent test of advanced perturbative QCD calculations. The ATLAS collaboration has performed detailed measurements of those differential cross sections at a centre-of-mass energy of 13 TeV. This talk focuses on differential cross-section measurements in the lepton+jets final state, including using boosted top quarks to probe our understanding of top quark production in the TeV regime.
International Nuclear Information System (INIS)
Hristova, I.
2007-12-01
We present the analysis of data taken in the years 2002-2004 with the 27.56 GeV positron beam of the HERA storage ring at DESY and the internal transversely polarised hydrogen fixed target of the HERMES experiment. Events with a scattered positron and a produced pion are selected. Exclusive production of single pions, e + p→e +' nπ + , is ensured by requiring the missing mass in the event to be equal to the mass of the neutron, which is not detected. The cross section for this process depends on the Bjorken scaling variable, the four-momentum transfer, and the transverse four-momentum transfer, whose average values for our sample are left angle x right angle =0.12, left angle Q 2 right angle =2.3 GeV 2 , left angle t' right angle =-0.18 GeV 2 , respectively, and two azimuthal angles: the angle φ between the scattering and production planes (their common line contains the virtual photon), and the angle φ S between the scattering plane and the target polarisation vector. The hard scattering is selected by requiring Q 2 >1 GeV 2 . The asymmetry, also called transverse-target single-spin azimuthal asymmetry, is defined as the ratio of the difference to the sum of the cross sections for positive and negative target polarisation. It is characterised by six azimuthal sine modulations, whose amplitudes can vary from -1 to 1. We measure the asymmetry from a sample of 2093 events with a signal-to-background ratio of 1: 1. At average kinematics, the values of the amplitudes are found to be small or consistent with zero, except for the amplitude A sinφ S UT,meas =0.38±0.06(stat) +0.12 -0.06 (syst). The amplitude of main interest for comparison with theory, A sin(φ-φ S ) UT,meas =0.09±0.05(stat) +0.10 -0.03 (syst), after correction for the background contribution becomes A sin(φ-φ S ) UT,bg.cor =0.22 ±0.13(stat) +0.10 -0.04 (syst). As a function of t', the measured values of this amplitude increase as √(-t') and at larger vertical stroke t' vertical stroke the
International Nuclear Information System (INIS)
Fuchi, H.; Hoshino, K.; Miyanishi, M.; Niu, K.; Niwa, K.; Shibuya, H.; Yanagisawa, Y.; Tasaka, S.; Maeda, Y.; Kimura, H.
1981-01-01
Among secondaries of 4323 interactions produced in an emulsion chamber exposed to a 340 GeV/c negative ion beam of CERN-SPS, 4 pairs of charmed particles were detected. The mean lifetime of D 0 (D 0 -bar) and the inclusive production cross-section of a charmed particle pair by 340 GeV/c pions were evaluated as (3.1sub(-1.6)sup(+ 2.0)) x 10 - 13 sec and 44 +- 22 μb. (author)
Energy Technology Data Exchange (ETDEWEB)
Fuchi, H; Hoshino, K; Miyanishi, M; Niu, K; Niwa, K; Shibuya, H; Yanagisawa, Y [Nagoya Univ. (Japan). Dept. of Physics; Ushida, N [Faculty of Education, Aichi University of Education, Kariya, Aichi (Japan); Tasaka, S [Tokyo Univ., Tanashi (Japan). Inst. for Cosmic Ray Research; Maeda, Y
1981-06-06
Among secondaries of 4323 interactions produced in an emulsion chamber exposed to a 340 GeV/c negative ion beam of CERN-SPS, 4 pairs of charmed particles were detected. The mean lifetime of D/sup 0/(D/sup 0/-bar) and the inclusive production cross-section of a charmed particle pair by 340 GeV/c pions were evaluated as (3.1sub(-1.6)sup(+ 2.0)) x 10/sup -13/ sec and 44 +- 22 ..mu..b.
Pion condensation in symmetric nuclear matter
Kabir, K.; Saha, S.; Nath, L. M.
1988-01-01
Using a model which is based essentially on the chiral SU(2)×SU(2) symmetry of the pion-nucleon interaction, we examine the possibility of pion condensation in symmetric nucleon matter. We find that the pion condensation is not likely to occur in symmetric nuclear matter for any finite value of the nuclear density. Consequently, no critical opalescence phenomenom is expected to be seen in the pion-nucleus interaction.
New meson-nucleus dynamics from studies of (π,eta) and (π,2π) reactions
International Nuclear Information System (INIS)
Liu, L.C.
1985-01-01
The production of eta particles by pion collisions with nucleons, the reaction with the lowest genuine two-body reaction threshold, is discussed. For simple kinematic reasons, the threshold for nuclear pionic eta production reactions is much lower than 661 MeV. Using an off-shell model for the eta production amplitudes, theoretical cross sections are given for the reaction 3 He(π - ,eta) 3 H(g.s.) at 620 and 720 MeV/c. Pion-induced single pion production is then treated. Because the basic cross sections for this reaction becomes comparable to the pion-nucleon elastic scattering cross section at pion kinetic energies of about 600 MeV and exceeds the elastic scattering cross section at 1 GeV, it is believed that the (π,2π) reaction in complex nuclei represents a powerful tool to study nuclei at pion energies above the resonance region. Theoretical cross section ratios are given for 40 Ca at three different pion energies accessible at LAMPF. Also, the corresponding cross-section ratios are presented on a free proton. 14 refs., 7 figs
Exclusive production of pion pairs in γ*γ collisions at Large Q2
International Nuclear Information System (INIS)
Diehl, M.
2000-01-01
The authors perform a QCD analysis of the exclusive production of two mesons in γ*γ collisions in the kinematical domain of large photon virtuality Q and small hadronic invariant mass W. This reaction is dominated by a scale invariant mechanism which factorizes into a perturbative subprocess, γ*γ -> q anti q or γ*γ -> gg, and a generalized two-meson distribution amplitude. The authors develop in detail the phenomenology of this process at e + e - colliders. Using a simple model for the two-pion distribution amplitude, based on its general properties, the authors estimate the cross section for the kinematics accessible at BABAR, BELLE, CLEO and LEP
Activation cross section data file, (1)
International Nuclear Information System (INIS)
Yamamuro, Nobuhiro; Iijima, Shungo.
1989-09-01
To evaluate the radioisotope productions due to the neutron irradiation in fission of fusion reactors, the data for the activation cross sections ought to be provided. It is planning to file more than 2000 activation cross sections at final. In the current year, the neutron cross sections for 14 elements from Ni to W have been calculated and evaluated in the energy range 10 -5 to 20 MeV. The calculations with a simplified-input nuclear cross section calculation system SINCROS were described, and another method of evaluation which is consistent with the JENDL-3 were also mentioned. The results of cross section calculation are in good agreement with experimental data and they were stored in the file 8, 9 and 10 of ENDF/B format. (author)
Pion production in nucleus--nucleus collisions
International Nuclear Information System (INIS)
Schroeder, L.S.
1975-06-01
Current work on pion production in high-energy nucleus-nucleus collisions is reviewed. The majority of existing data are of the inclusive variety in which a single final state pion is detected. Experimental data are compared and their possible contributions to obtaining new information on nuclear structure is discussed. Various models which attempt to explain the observed single-inclusive-pion spectra either on the basis of a nucleon-nucleus interaction in which Fermi motion is included or on some type of cooperative model are examined. Other areas of interest involving pion production include tests of charge symmetry and pion multiplicities. (9 figures, 1 table) (U.S.)
Utilization of cross-section covariance data in FBR core nuclear design and cross-section adjustment
International Nuclear Information System (INIS)
Ishikawa, Makoto
1994-01-01
In the core design of large fast breeder reactors (FBRs), it is essentially important to improve the prediction accuracy of nuclear characteristics from the viewpoint of both reducing cost and insuring reliability of the plant. The cross-section errors, that is, covariance data are one of the most dominant sources for the prediction uncertainty of the core parameters, therefore, quantitative evaluation of covariance data is indispensable for FBR core design. The first objective of the present paper is to introduce how the cross-section covariance data are utilized in the FBR core nuclear design works. The second is to delineate the cross-section adjustment study and its application to an FBR design, because this improved design method markedly enhances the needs and importance of the cross-section covariance data. (author)
Chvala, O.; Makariev, M.; Rybicki, A.; Varga, D.; Wenig, S.
2013-01-01
New data on proton and pion production in p+C interactions from the CERN PS and SPS accelerators are used in conjunction with other available data sets to perform a comprehensive survey of backward hadronic cross sections. This survey covers the complete backward hemisphere in the range of lab angles from 10 to 180 degrees, from 0.2 to 1.4 GeV/c in lab momentum and from 1 to 400 GeV/c in projectile momentum. Using the constraints of continuity and smoothness of the angular, momentum and energy dependences a consistent description of the inclusive cross sections is established which allows the control of the internal consistency of the nineteen available data sets.
Pion condensation in symmetric nuclear matter
International Nuclear Information System (INIS)
Kabir, K.; Saha, S.; Nath, L.M.
1987-09-01
Using a model which is based essentially on the chiral SU(2)xSU(2) symmetry of the pion-nucleon interaction, we examine the possibility of pion condensation in symmetric nucleon matter. We find that the pion condensation is not likely to occur in symmetric nuclear matter for any finite value of the nuclear density. Consequently, no critical opalescence phenomenon is expected to be seen in the pion-nucleus interaction. (author). 20 refs
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.)
Energy Technology Data Exchange (ETDEWEB)
Apokin, V D; Vasiliev, A N; Derevshchikov, A A; Matulenko, Yu A; Meschanin, A P; Mysnik, A I; Nurushev, S B; Saraykin, A I; Siksin, V V; Smirnov, E V [Gosudarstvennyj Komitet po Ispol' zovaniyu Atomnoj Ehnergii SSSR, Serpukhov. Inst. Fiziki Vysokikh Ehnergij
1976-04-19
Differential cross sections for the elastic scattering of negative pions on protons, as well as total cross sections have been measured for the incident momentum range from 33 up to 60 GeV/c. The values for four-momentum transfer were within the limits of -(10/sup -3/-8x10/sup -2/) (GeV/c)/sup 2/. The energy dependence of the ratio rho(0) of the real part of the forward elastic scattering amplitude to the imaginary part has been determined from the experimental data. The magnitude rho(0) smoothly increases from (-10.9+-1.2)% at momenta 33.52 GeV/c up to (-1.8+-1.8)% at 59.4 GeV/c. The results obtained are compared with the predictions of theoretical models.
JENDL gas-production cross section file
International Nuclear Information System (INIS)
Nakagawa, Tsuneo; Narita, Tsutomu
1992-05-01
The JENDL gas-production cross section file was compiled by taking cross-section data from JENDL-3 and by using the ENDF-5 format. The data were given to 23 nuclei or elements in light nuclei and structural materials. Graphs of the cross sections and brief description on their evaluation methods are given in this report. (author)
International Nuclear Information System (INIS)
Mayer, R.S.
1992-11-01
In the framework of the TAPS collaboration at GANIL an experiment for the production of neutral pions in 129 Xe+ 197 Au collisions below the threshold for the production in the free nucleon-nucleon collision was performed. Both for π 0 and for hard photons from the data the inclusive cross sections for the production, energy and angular distributions as well as the velocity of the emitting source were derived. (orig./HSI) [de
Doppler broadening of cross sections
International Nuclear Information System (INIS)
Buckler, P.A.C.; Pull, I.C.
1962-12-01
Expressions for temperature dependent cross-sections in terms of resonance parameters are obtained, involving generalisations of the conventional Doppler functions, ψ and φ. Descriptions of Fortran sub-routines, which calculate broadened cross-sections in accordance with the derived formulae, are included. (author)
Twist-2 Light-Cone Pion Wave Function
Belyaev, V. M.; Johnson, Mikkel B.
1997-01-01
We present an analysis of the existing constraints for the twist-2 light-cone pion wave function. We find that existing information on the pion wave function does not exclude the possibility that the pion wave function attains its asymptotic form. New bounds on the parameters of the pion wave function are presented.
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
Radiation-accompanied pion photoproduction on the proton
International Nuclear Information System (INIS)
Rost, M.
2004-01-01
In the year 1997, Tatischeff et al. found resonance-like states in the invariant mass spectrum of the missing particle X at M=1004, 1044 and 1094 MeV, utilizing the reaction pp→Xpπ + . Investigating the reaction pd→ppX, resonance structures have been observed at M=966, 986 and 1003 MeV in a further experiment by Filkov et al. Such kinds of exotic states contradict various nucleon models which describe the Δ(1232) resonance as the first excited state. Instead, quark cluster models with and without color-magnetic interactions have been formulated to explain these resonance structures. Lvov et al. argued that no such structure had been reported in real Compton scattering data. As a counter argument, Kobushkin suggested that these resonances have a total anti-symmetric spin-flavour wave function and therefore only the N-2γ decay channel is allowed. In this work, the reaction γp→X 0 π + →nγγπ + is utilized for the search of these exotic resonances. Data were taken in parallel with the pion polarizability experiment at the MAMI accelerator facility in Mainz. Real photons are created by the bremsstrahlung process of the electrons in a thin radiator foil. Their energy is determined by the A2 photon tagging facility (Glasgow tagger). A 10 cm long liquid hydrogen target was used as a proton target. Charged reaction products are detected in a multi wire proportional chamber in forward direction, at theta 2 crystals containing TAPS spectrometer at polar angles of theta >60 . For neutron detection, a time of flight detector with 111 single modules was used. Additionally, the reaction channels γp→pπ 0 and γp→nπ 0 π + are analysed to test the apparatuses. For single pion production, differential cross sections are obtained and compared with theoretical models as well as experimental data. For the γp→nπ 0 π + channel, invariant mass spectra of particles in the final state are determined and compared with simulation. The data indicate that the main
International Nuclear Information System (INIS)
Roberts, C.D.
1995-01-01
Herein the application of the DSE approach to the calculation of pion observables is described using: the π-π scattering lengths (a 0 0 , a 2 0 , a 1 1 , a 0 2 , a 2 2 ) and associated partial wave amplitudes; the π 0 → γγ decay width; and the charged pion form factor, F π (q 2 ), as illustrative examples. Since this approach provides a straightforward, microscopic description of dynamical chiral symmetry breaking (DχSB) and confinement, the calculation of pion observables is a simple and elegant illustrative example of its power and efficacy. (orig.)
Cross-sectional anatomy for computed tomography
International Nuclear Information System (INIS)
Farkas, M.L.
1988-01-01
This self-study guide recognizes that evaluation and interpretation of CT-images demands a firm understanding of both cross-sectional anatomy and the principles of computed tomography. The objectives of this book are: to discuss the basic principles of CT, to stress the importance of cross-sectional anatomy to CT through study of selected cardinal transverse sections of head, neck, and trunk, to explain orientation and interpretation of CT-images with the aid of corresponding cross-sectional preparations
Density-dependent expressions for photoionization cross-sections
International Nuclear Information System (INIS)
Sun Weiguo; Ma Xiaoguang; Cheng Yansong
2004-01-01
Alternative expressions for photoionization cross-sections and dielectric influence functions are suggested to study the photoionization cross-sections of atoms in solid system. The basic picture is that the photoionization cross-section of atoms in a real system can be described as the coupling between quantum quantity (QQ) and classical quantity (CQ) parts. The QQ part represents the photoionization cross-sections of an isolated particle, while the CQ part may represent most of the important influence of the macroscopic effects (e.g., the interactions of all surrounding polarized particles, and the dielectric property, etc.) on the photoionization cross-sections. The applications to the barium system show that the number-density-dependent new photoionization formula not only obtains the same cross-sections as those from the first order approximation for ideal gas, but also can generate the cross-sections for solid barium by transforming those of ideal gas of the same species using the dielectric influence function
Density-dependent expressions for photoionization cross-sections
Energy Technology Data Exchange (ETDEWEB)
Sun Weiguo; Ma Xiaoguang; Cheng Yansong
2004-06-07
Alternative expressions for photoionization cross-sections and dielectric influence functions are suggested to study the photoionization cross-sections of atoms in solid system. The basic picture is that the photoionization cross-section of atoms in a real system can be described as the coupling between quantum quantity (QQ) and classical quantity (CQ) parts. The QQ part represents the photoionization cross-sections of an isolated particle, while the CQ part may represent most of the important influence of the macroscopic effects (e.g., the interactions of all surrounding polarized particles, and the dielectric property, etc.) on the photoionization cross-sections. The applications to the barium system show that the number-density-dependent new photoionization formula not only obtains the same cross-sections as those from the first order approximation for ideal gas, but also can generate the cross-sections for solid barium by transforming those of ideal gas of the same species using the dielectric influence function.
Total neutron cross section of lead
International Nuclear Information System (INIS)
Kanda, K.; Aizawa, O.
1976-01-01
The total thermal-neutron cross section of natural lead under various physical conditions was measured by the transmission method. It became clear that the total cross section at room temperature previously reported is lower than the present data. The total cross section at 400, 500, and 600 0 C, above the melting point of lead, 327 0 C, was also measured, and the changes in the cross section as a function of temperature were examined, especially near and below the melting point. The data obtained for the randomly oriented polycrystalline state at room temperature were in reasonable agreement with the theoretical values calculated by the THRUSH and UNCLE-TOM codes
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)
Evaluation of neutron- and proton-induced cross sections of {sup 27}Al up to 2 GeV
Energy Technology Data Exchange (ETDEWEB)
Lee, Young-Ouk; Chang, Jonghwa [Korea Atomic Energy Research Institute, Yusung, Taejon (Korea, Republic of); Fukahori, Tokio; Chiba, Satoshi
1999-03-01
We have evaluated neutron and proton nuclear data of {sup 27}Al for energies up to 2 GeV. The best set of optical model parameters were obtained above 20 MeV for neutron and above reaction threshold for proton up to 250 MeV with the phenomenological potential forms proposed by Chiba. The transmission coefficients for neutron and proton derived from the optical models are fed into the GNASH code system to calculate angle-energy correlated emission spectra for light ejectiles and gamma rays. For energies above 250 MeV and below 2 GeV, the total, reaction and elastic scattering cross sections were evaluated by an empirical fit and recent systematics. Emitted nucleon and pion were estimated by use of QMD + SDM (Quantum Molecular Dynamics + Statistical Decay Model). (author)
Top quark production cross-section measurements
Chen, Ye; The ATLAS collaboration
2017-01-01
Measurements of the inclusive and differential cross-sections for top-quark pair and single top production cross sections in proton-proton collisions with the ATLAS detector at the Large Hadron Collider are presented at center-of-mass energies of 8 TeV and 13 TeV. The inclusive measurements reach high precision and are compared to the best available theoretical calculations. These measurements, including results using boosted tops, probe our understanding of top-pair production in the TeV regime. The results are compared to Monte Carlo generators implementing LO and NLO matrix elements matched with parton showers and NLO QCD calculations. For the t-channel single top measurement, the single top-quark and anti-top-quark total production cross-sections, their ratio, as well as differential cross sections are also presented. A measurement of the production cross-section of a single top quark in association with a W boson, the second largest single-top production mode, is also presented. Finally, measurements of ...
Characteristic aspects of pion-condensed phases
International Nuclear Information System (INIS)
Takatsuka, Tatsuyuki; Tamagaki, Ryozo; Tatsumi, Toshitaka.
1993-01-01
Characteristic aspects of pion-condensed phases are described in a simple model, for the system involving only nucleons and pions which interact through the π-N P-wave interaction. We consider one typical version in each of three kinds of pion condensation; the one of neutral pions (π 0 ), the one of charged pions (π C ) and the combined one in which both the π 0 and π C condensations are coexistent. Emphasis is put on the description to clarify the novel structures of the nucleon system which are realized in the pion-condensed phases. At first, it is shown that the π 0 condensation is equivalent to the particular nucleonic phase realized by a structure change of the nucleon system, where the attractive first-order effect of the one-pion-exchange (OPE) tensor force is brought about coherently. The aspects of this phase are characterized by the layered structure with a specific spin-isospin order with one-dimensional localization (named the ALS structure in short), which provides the source function for the condensed π 0 field. We utilize both descriptions with use of fields and potentials for the π 0 condensation. Next, the π C condensation realized in neutron-rich matter is described by adopting a version of the traveling condensed wave. In this phase, the nucleonic structure becomes the Fermi gas consisting of quasi-neutrons described by a superposition of neutron and proton. In this sense the structure change of the nucleon system for the π C condensation is moderate, and the field description is suitable. Finally, we describe a coexistent pion condensation, in which both the π 0 and π C condensations coexist without interference in such a manner that the π C condensation develops in the ALS structure. The model adopted here provides us with the characteristic aspects of the pion-condensed phases persisting in the realistic situation, where other ingredients affecting the pion condensation are taken into account. (author)
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.
International Nuclear Information System (INIS)
Linden, Steven K.
2011-01-01
Charged current single pion production (CCπ + ) and charged current quasi-elastic scattering (CCQE) are the most abundant interaction types for neutrinos at energies around 1 GeV, a region of great interest to oscillation experiments. The cross-sections for these processes, however, are not well understood in this energy range. This dissertation presents a measurement of the ratio of CCπ + to CCQE cross-sections for muon neutrinos on mineral oil (CH 2 ) in the MiniBooNE experiment. The measurement is presented here both with and without corrections for hadronic re-interactions in the target nucleus and is given as a function of neutrino energy in the range 0.4 GeV ν + events collected in MiniBooNE, and with a fractional uncertainty of roughly 11% in the region of highest statistics, this measurement represents a dramatic improvement in statistics and precision over previous CCπ + and CCQE measurements.
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
Differences between LASL- and ANL-processed cross sections
International Nuclear Information System (INIS)
Kidman, R.B.; MacFarlane, R.E.; Becker, M.
1978-03-01
As part of the Los Alamos Scientific Laboratory (LASL) cross-section processing development, LASL cross sections and results from MINX/1DX system are compared to the Argonne National Laboratory cross sections and results from the ETOE-2/MC 2 -2 system for a simple reactor problem. Exact perturbation theory is used to establish the eigenvalue effect of every isotope group cross-section difference. Cross sections, cross-section differences, and their eigenvalue effects are clearly and conveniently displayed and compared on a group-by-group basis
Ranking and validation of spallation models for isotopic production cross sections of heavy residua
Sharma, Sushil K.; Kamys, Bogusław; Goldenbaum, Frank; Filges, Detlef
2017-07-01
The production cross sections of isotopically identified residual nuclei of spallation reactions induced by 136Xe projectiles at 500AMeV on hydrogen target were analyzed in a two-step model. The first stage of the reaction was described by the INCL4.6 model of an intranuclear cascade of nucleon-nucleon and pion-nucleon collisions whereas the second stage was analyzed by means of four different models; ABLA07, GEM2, GEMINI++ and SMM. The quality of the data description was judged quantitatively using two statistical deviation factors; the H-factor and the M-factor. It was found that the present analysis leads to a different ranking of models as compared to that obtained from the qualitative inspection of the data reproduction. The disagreement was caused by sensitivity of the deviation factors to large statistical errors present in some of the data. A new deviation factor, the A factor, was proposed, that is not sensitive to the statistical errors of the cross sections. The quantitative ranking of models performed using the A-factor agreed well with the qualitative analysis of the data. It was concluded that using the deviation factors weighted by statistical errors may lead to erroneous conclusions in the case when the data cover a large range of values. The quality of data reproduction by the theoretical models is discussed. Some systematic deviations of the theoretical predictions from the experimental results are observed.
Ranking and validation of spallation models for isotopic production cross sections of heavy residua
Energy Technology Data Exchange (ETDEWEB)
Sharma, Sushil K.; Kamys, Boguslaw [Jagiellonian University, The Marian Smoluchowski Institute of Physics, Krakow (Poland); Goldenbaum, Frank; Filges, Detlef [Forschungszentrum Juelich, Institut fuer Kernphysik, Juelich (Germany)
2017-07-15
The production cross sections of isotopically identified residual nuclei of spallation reactions induced by {sup 136}Xe projectiles at 500 AMeV on hydrogen target were analyzed in a two-step model. The first stage of the reaction was described by the INCL4.6 model of an intranuclear cascade of nucleon-nucleon and pion-nucleon collisions whereas the second stage was analyzed by means of four different models; ABLA07, GEM2, GEMINI++ and SMM. The quality of the data description was judged quantitatively using two statistical deviation factors; the H-factor and the M-factor. It was found that the present analysis leads to a different ranking of models as compared to that obtained from the qualitative inspection of the data reproduction. The disagreement was caused by sensitivity of the deviation factors to large statistical errors present in some of the data. A new deviation factor, the A factor, was proposed, that is not sensitive to the statistical errors of the cross sections. The quantitative ranking of models performed using the A-factor agreed well with the qualitative analysis of the data. It was concluded that using the deviation factors weighted by statistical errors may lead to erroneous conclusions in the case when the data cover a large range of values. The quality of data reproduction by the theoretical models is discussed. Some systematic deviations of the theoretical predictions from the experimental results are observed. (orig.)
Slow proton production in semi-inclusive deep inelastic scattering and the pion cloud in the nucleon
Energy Technology Data Exchange (ETDEWEB)
Szczurek, A. [Institute of Nuclear Physics, Cracow (Poland); Bosveld, G.D.; Dieperink, E.L. [Rijksuniversiteit Groningen (Netherlands). Kernfysisch Versneller Inst.
1994-11-01
The semi-inclusive cross section for production slow protons in charged current deep inelastic (anti-) neutrino scattering on protons and neutrons is calculated as a function of the Bjorken x and the proton momentum. The standard hadronization models based upon the colour neutralization mechanism appear to underestimate the rate of slow proton production on hydrogen. The presence of virtual mesons (pions) in the nucleon leads to an additional mechanism for proton production, referred to as spectator process. It is found that at low proton momenta both mechanisms complete, whereas the spectator mechanism dominates at very small momenta, while the color neutralization mechanism dominates at momenta larger than 1-2 GeV/c. The results of the calculations are compared with CERN bubble chamber (BEBC) data. The spectator model predicts an sharp increase of the semi-inclusive cross section at small x due to the sea quarks in virtual mesons. (author). 37 refs, 10 figs.
Energy Technology Data Exchange (ETDEWEB)
Sanami, Toshiya; Baba, Mamoru; Saito, Keiichiro; Ibara, Yasutaka; Hirakawa, Naohiro [Tohoku Univ., Sendai (Japan). Faculty of Engineering
1997-03-01
We are developing a method of (n,{alpha}) cross section measurement using gaseous samples in a gridded ionization chamber (GIC). This method enables cross section measurements in large solid angle without the distortion by the energy loss in a sample, but requires a method to estimate the detection efficiency. We solve this problem by using GIC signals and a tight neutron collimation. The validity of this method was confirmed through the {sup 12}C(n,{alpha}{sub 0}){sup 9}Be measurement. We applied this method to the {sup 16}O(n,{alpha}){sup 13}C cross section around 14.1 MeV. (author)
Energy Technology Data Exchange (ETDEWEB)
Hristova, I.
2007-12-15
We present the analysis of data taken in the years 2002-2004 with the 27.56 GeV positron beam of the HERA storage ring at DESY and the internal transversely polarised hydrogen fixed target of the HERMES experiment. Events with a scattered positron and a produced pion are selected. Exclusive production of single pions, e{sup +}p{yields}e{sup +'}n{pi}{sup +}, is ensured by requiring the missing mass in the event to be equal to the mass of the neutron, which is not detected. The cross section for this process depends on the Bjorken scaling variable, the four-momentum transfer, and the transverse four-momentum transfer, whose average values for our sample are left angle x right angle =0.12, left angle Q{sup 2} right angle =2.3 GeV{sup 2}, left angle t' right angle =-0.18 GeV{sup 2}, respectively, and two azimuthal angles: the angle {phi} between the scattering and production planes (their common line contains the virtual photon), and the angle {phi}{sub S} between the scattering plane and the target polarisation vector. The hard scattering is selected by requiring Q{sup 2}>1 GeV{sup 2}. The asymmetry, also called transverse-target single-spin azimuthal asymmetry, is defined as the ratio of the difference to the sum of the cross sections for positive and negative target polarisation. It is characterised by six azimuthal sine modulations, whose amplitudes can vary from -1 to 1. We measure the asymmetry from a sample of 2093 events with a signal-to-background ratio of 1: 1. At average kinematics, the values of the amplitudes are found to be small or consistent with zero, except for the amplitude A{sup sin{phi}{sub SUT,meas}}=0.38{+-}0.06(stat){sup +0.12}{sub -0.06}(syst). The amplitude of main interest for comparison with theory, A{sup sin({phi}-{phi}{sub S})}{sub UT,meas}=0.09{+-}0.05(stat){sup +0.10}{sub -0.03}(syst), after correction for the background contribution becomes A{sup sin({phi}-{phi}{sub S})}{sub UT,bg.cor}=0.22 {+-}0.13(stat){sup +0.10}{sub -0
A cross section measurement of charm hyperons Ξc+ and Ξc0 in 250 GeV p/K/π-nucleon interactions
International Nuclear Information System (INIS)
Francisco, J.; Vergara, A.
1995-01-01
Fermilab Experiment 769 used a charge-selected, hadron beam of mean energy 250 GeV/c, composed of pions, kaons, and protons, impinging on beryllium, aluminum, copper and tungsten targets. Using a sample of approximately 4000 Ξ s - → Λ 0 π - decays, measurements of the charm baryon forward cross sections times branching ratio π ± N → Ξ c + X and π ± N → Ξ c 0 X are presented. Upper limits on α x BR are also determined for the states Ξ c + → Ξ s - π + π + and Ξ c 0 → Ξ s - π + produced in (p, π + , π - , K + , K - )-nucleon interactions
Photoionization cross section of atomic and molecular oxygen
International Nuclear Information System (INIS)
Pareek, P.N.
1983-01-01
Photoionization cross sections of atomic oxygen and dissociative photoionization cross sections of molecular oxygen were measured from their respective thresholds to 120 angstrom by use of a photoionization mass spectrometer in conjunction with a spark light source. The photoionization cross sections O 2 + parent ion and O + fragment ion from neutral O 2 were obtained by a technique that eliminated the serious problem of identifying the true abundances of O + ions. These ions are generally formed with considerable kinetic energy and, because most mass spectrometers discriminate against energetic ions, true O + abundances are difficult to obtain. In the present work the relative cross sections for producing O + ions are obtained and normalized against the total cross sections in a spectral region where dissociative ionization is not possible. The fragmentation cross sections for O + were then obtained by subtraction of O 2 + cross sections from the known total photoionization cross sections. The results are compared with the previously published measurements. The absolute photoionization cross section of atomic oxygen sigma 8 /sub +/ was measured at 304 A. The actual number density of oxygen atoms within the ionization region was obtained by measuring the fraction of 0 2 molecules dissociated. This sigma/sub +/ at 304 angstrom was used to convert the relative photoinization cross sections, measured as a function of wavelength using a calibrated photodiode, to absolute cross sections. The results are compared with previous measurements and calculated cross sections. angstrom Rydberg series converging to the OII 4 P state was observed
Measurements of neutron capture cross sections
International Nuclear Information System (INIS)
Nakajima, Yutaka
1984-01-01
A review of measurement techniques for the neutron capture cross sections is presented. Sell transmission method, activation method, and prompt gamma-ray detection method are described using examples of capture cross section measurements. The capture cross section of 238 U measured by three different prompt gamma-ray detection methods (large liquid scintillator, Moxon-Rae detector, and pulse height weighting method) are compared and their discrepancies are resolved. A method how to derive the covariance is described. (author)
XCOM: Photon Cross Sections Database
SRD 8 XCOM: Photon Cross Sections Database (Web, free access) A web database is provided which can be used to calculate photon cross sections for scattering, photoelectric absorption and pair production, as well as total attenuation coefficients, for any element, compound or mixture (Z <= 100) at energies from 1 keV to 100 GeV.
Charge dependence of the pion-nucleon coupling constant
Directory of Open Access Journals (Sweden)
V. A. Babenko
2015-07-01
Full Text Available On the basis of the Yukawa potential we study the pion-nucleon coupling constants for the neutral and charged pions assuming that nuclear forces at low energies are mainly determined by the exchange of virtual pions. We obtain the charged pseudovector pion-nucleon coupling constant f2π± = 0.0804(7 by making the use of experimental low-energy scattering parameters for the singlet pp- and np-scattering, and also by use of the neutral pseudovector pion-nucleon coupling constant f2π0 = 0.0749(7. Corresponding value of the charged pseudoscalar pion-nucleon coupling constant g2π0 / 4π = 14.55(13 is also determined. This calculated value of the charged pseudoscalar pion-nucleon coupling constant is in fully agreement with the experimental constant g2π0 / 4π = 14.52(26 obtained by the Uppsala Neutron Research Group. Our results show considerable charge splitting of the pion-nucleon coupling constant.
Pion-nucleus scattering in the isobar formalism
International Nuclear Information System (INIS)
Moniz, E.J.
1978-06-01
Lectures on the isobar-hole model for pion reactions include the isobar as an explicit degree of freedom and the connection with a purely pion and nucleon system, the formalism and its relation to the pion optical potential, the extended schematic model for pion scattering, a simple spinless s-wave model, application to pion-oxygen 16 scattering and comparison with elastic scattering data. In this way the extent is shown to which microscopic treatment of the many-body dynamics explains the data and the extent to which additional physical input is required. Another test is the various inelastic processes. Inclusive reactions are briefly discussed. 37 references
International Nuclear Information System (INIS)
Soran, P.D.; Seamon, R.E.
1980-05-01
Graphs of all neutron cross sections and photon production cross sections on the Recommended Monte Carlo Cross Section (RMCCS) library have been plotted along with local neutron heating numbers. Values for anti ν, the average number of neutrons per fission, are also given
Scattering cross section for various potential systems
Directory of Open Access Journals (Sweden)
Myagmarjav Odsuren
2017-08-01
Full Text Available We discuss the problems of scattering in this framework, and show that the applied method is very useful in the investigation of the effect of the resonance in the observed scattering cross sections. In this study, not only the scattering cross sections but also the decomposition of the scattering cross sections was computed for the α–α system. To obtain the decomposition of scattering cross sections into resonance and residual continuum terms, the complex scaled orthogonality condition model and the extended completeness relation are used. Applying the present method to the α–α and α–n systems, we obtained good reproduction of the observed phase shifts and cross sections. The decomposition into resonance and continuum terms makes clear that resonance contributions are dominant but continuum terms and their interference are not negligible. To understand the behavior of observed phase shifts and the shape of the cross sections, both resonance and continuum terms are calculated.
Scattering cross section for various potential systems
Energy Technology Data Exchange (ETDEWEB)
Odsuren, Myagmarjav; Khuukhenkhuu, Gonchigdorj; Davaa, Suren [Nuclear Research Center, School of Engineering and Applied Sciences, National University of Mongolia, Ulaanbaatar (Mongolia); Kato, Kiyoshi [Nuclear Reaction Data Centre, Faculty of Science, Hokkaido University, Sapporo (Japan)
2017-08-15
We discuss the problems of scattering in this framework, and show that the applied method is very useful in the investigation of the effect of the resonance in the observed scattering cross sections. In this study, not only the scattering cross sections but also the decomposition of the scattering cross sections was computed for the α–α system. To obtain the decomposition of scattering cross sections into resonance and residual continuum terms, the complex scaled orthogonality condition model and the extended completeness relation are used. Applying the present method to the α–α and α–n systems, we obtained good reproduction of the observed phase shifts and cross sections. The decomposition into resonance and continuum terms makes clear that resonance contributions are dominant but continuum terms and their interference are not negligible. To understand the behavior of observed phase shifts and the shape of the cross sections, both resonance and continuum terms are calculated.
Magnetic polarizability of pion
Energy Technology Data Exchange (ETDEWEB)
Luschevskaya, E.V., E-mail: luschevskaya@itep.ru [Institute for Theoretical and Experimental Physics, Bolshaia Cheremushkinskaia 25, 117218 Moscow (Russian Federation); School of Biomedicine, Far Eastern Federal University, 690950 Vladivostok (Russian Federation); Solovjeva, O.E., E-mail: olga.solovjeva@itep.ru [Institute for Theoretical and Experimental Physics, Bolshaia Cheremushkinskaia 25, 117218 Moscow (Russian Federation); Teryaev, O.V., E-mail: teryaev@theor.jinr.ru [Joint Institute for Nuclear Research, Dubna, 141980 (Russian Federation); National Research Nuclear University “MEPhI” (Moscow Engineering Physics Institute), Kashirskoe highway, 31, 115409 Moscow (Russian Federation)
2016-10-10
We explore the energy dependence of π mesons off the background Abelian magnetic field on the base of quenched SU(3) lattice gauge theory and calculate the magnetic dipole polarizability of charged and neutral pions for various lattice volumes and lattice spacings. The contribution of the magnetic hyperpolarizability to the neutral pion energy has been also found.
NNLO jet cross sections by subtraction
International Nuclear Information System (INIS)
Somogyi, G.; Bolzoni, P.; Trocsanyi, Z.
2010-06-01
We report on the computation of a class of integrals that appear when integrating the so-called iterated singly-unresolved approximate cross section of an earlier NNLO subtraction scheme over the factorised phase space of unresolved partons. The integrated approximate cross section itself can be written as the product of an insertion operator (in colour space) times the Born cross section. We give selected results for the insertion operator for processes with two and three hard partons in the final state. (orig.)
NNLO jet cross sections by subtraction
Energy Technology Data Exchange (ETDEWEB)
Somogyi, G.; Bolzoni, P. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Trocsanyi, Z. [CERN, Geneva (Switzerland)
2010-06-15
We report on the computation of a class of integrals that appear when integrating the so-called iterated singly-unresolved approximate cross section of an earlier NNLO subtraction scheme over the factorised phase space of unresolved partons. The integrated approximate cross section itself can be written as the product of an insertion operator (in colour space) times the Born cross section. We give selected results for the insertion operator for processes with two and three hard partons in the final state. (orig.)
NNLO jet cross sections by subtraction
Somogyi, Gabor; Trocsanyi, Zoltan
2010-01-01
We report on the computation of a class of integrals that appear when integrating the so-called iterated singly-unresolved approximate cross section of the NNLO subtraction scheme of [1-4], over the factorised phase space of unresolved partons. The integrated approximate cross section itself can be written as the product of an insertion operator (in colour space) times the Born cross section. We give selected results for the insertion operator for processes with two and three hard partons in the final state.
International Nuclear Information System (INIS)
Khakoo, M. A.; Wrkich, J.; Larsen, M.; Kleiban, G.; Kanik, I.; Trajmar, S.; Brunger, M.J.; Teubner, P.J.O.; Crowe, A.; Fontes, C.J.; Clark, R.E.H.; Zeman, V.; Bartschat, K.; Madison, D.H.; Srivastava, R.; Stauffer, A.D.
2002-01-01
Electron-impact differential cross-section measurements for the excitation of the 2p 5 3s configuration of Ne are reported. The Ne cross sections are obtained using experimental differential cross sections for the electron-impact excitation of the n=2 levels of atomic hydrogen [Khakoo et al., Phys. Rev. A 61, 012701-1 (1999)], and existing experimental helium differential cross-section measurements, as calibration standards. These calibration measurements were made using the method of gas mixtures (Ne and H followed by Ne and He), in which the gas beam profiles of the mixed gases are found to be the same within our experimental errors. We also present results from calculations of these differential cross sections using the R-matrix and unitarized first-order many-body theory, the distorted-wave Born approximation, and relativistic distorted-wave methods. Comparison with available experimental differential cross sections and differential cross-section ratios is also presented
Capture cross sections on unstable nuclei
Tonchev, A. P.; Escher, J. E.; Scielzo, N.; Bedrossian, P.; Ilieva, R. S.; Humby, P.; Cooper, N.; Goddard, P. M.; Werner, V.; Tornow, W.; Rusev, G.; Kelley, J. H.; Pietralla, N.; Scheck, M.; Savran, D.; Löher, B.; Yates, S. W.; Crider, B. P.; Peters, E. E.; Tsoneva, N.; Goriely, S.
2017-09-01
Accurate neutron-capture cross sections on unstable nuclei near the line of beta stability are crucial for understanding the s-process nucleosynthesis. However, neutron-capture cross sections for short-lived radionuclides are difficult to measure due to the fact that the measurements require both highly radioactive samples and intense neutron sources. Essential ingredients for describing the γ decays following neutron capture are the γ-ray strength function and level densities. We will compare different indirect approaches for obtaining the most relevant observables that can constrain Hauser-Feshbach statistical-model calculations of capture cross sections. Specifically, we will consider photon scattering using monoenergetic and 100% linearly polarized photon beams. Challenges that exist on the path to obtaining neutron-capture cross sections for reactions on isotopes near and far from stability will be discussed.
Status of neutron dosimetry cross sections
International Nuclear Information System (INIS)
Griffin, P.J.; Kelly, J.G.
1992-01-01
Several new cross section libraries, such as ENDF/B-VI(release 2), IRDF-90,JEF-2.2, and JENDL-3 Dosimetry, have recently been made available to the dosimetry community. the Sandia National Laboratories (SNL) Radiation Metrology Laboratory (RML) has worked with these libraries since pre-release versions were available. this paper summarizes the results of the intercomparison and testing of dosimetry cross sections. As a result of this analysis, a compendium of the best dosimetry cross sections was assembled from the available libraries for use within the SNL RML. this library, referred to as the SNLRML Library, contains 66 general dosimetry sensors and 3 special dosimeters unique to the RML sensor inventory. The SNLRML cross sections have been put into a format compatible with commonly used spectrum determination codes
Capture cross sections on unstable nuclei
Directory of Open Access Journals (Sweden)
Tonchev A.P.
2017-01-01
Full Text Available Accurate neutron-capture cross sections on unstable nuclei near the line of beta stability are crucial for understanding the s-process nucleosynthesis. However, neutron-capture cross sections for short-lived radionuclides are difficult to measure due to the fact that the measurements require both highly radioactive samples and intense neutron sources. Essential ingredients for describing the γ decays following neutron capture are the γ-ray strength function and level densities. We will compare different indirect approaches for obtaining the most relevant observables that can constrain Hauser-Feshbach statistical-model calculations of capture cross sections. Specifically, we will consider photon scattering using monoenergetic and 100% linearly polarized photon beams. Challenges that exist on the path to obtaining neutron-capture cross sections for reactions on isotopes near and far from stability will be discussed.
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
International Nuclear Information System (INIS)
Seamon, R.E.; Soran, P.D.
1980-06-01
Graphs of all neutron cross sections and photon production cross sections on the Alternate Monte Carlo Cross Section (AMCCS) library have been plotted along with local neutron heating numbers. The values of ν-bar, the average number of neutrons per fission, are also plotted for appropriate isotopes
Energy Technology Data Exchange (ETDEWEB)
Kaiser, N.; Petschauer, S. [Technische Universitaet Muenchen, Physik-Department T39, Garching (Germany)
2013-12-15
We calculate the one-photon loop radiative corrections to the charged pion-pair production process {pi}{sup -}{gamma} {yields} {pi}{sup +}{pi}{sup -}{pi}{sup -}. In the low-energy region this reaction is governed by the chiral pion-pion interaction. The pertinent set of 42 irreducible photon-loop diagrams is calculated by using the package FeynCalc. Electromagnetic counterterms with two independent low-energy constants k{sub 1} and k{sub 2} are included in order to remove the ultraviolet divergences generated by the photon loops. Infrared finiteness of the virtual radiative corrections is achieved by including soft photon radiation below an energy cut-off {Lambda}. The purely electromagnetic interaction of the charged pions mediated by one-photon exchange is also taken into account. The radiative corrections to the total cross section (in the isospin limit) vary between +10% close to threshold and about -1% at a center-of-mass energy of 7m{sub {pi}}. The largest contribution comes from the simple one-photon exchange. Radiative corrections to the {pi}{sup +}{pi}{sup -} and {pi}{sup -}{pi}{sup -} mass spectra are studied as well. The Coulomb singularity of the final-state interaction produces a kink in the dipion mass spectra. The virtual radiative corrections to elastic {pi}{sup -}{pi}{sup -} scattering are derived additionally. (orig.)
International Nuclear Information System (INIS)
Bantes, B.
2003-10-01
A complete Monte Carlo simulation for the neutral pion electroproduction experiment in the kinematics of the Δ(1232) that was carried out at the accelerator facility ELSA has been developed to correct the data concerning effects like detector resolution efficiencies, acceptances and radiation corrections. Results for the leading amplitudes are extracted at the four momentum transfer of 0.630 GeV 2 . Absolute cross sections are extracted using the well known elastic ep scattering to determine the luminosity. (orig.)
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
Neutron-capture Cross Sections from Indirect Measurements
Energy Technology Data Exchange (ETDEWEB)
Escher, J E; Burke, J T; Dietrich, F S; Ressler, J J; Scielzo, N D; Thompson, I J
2011-10-18
Cross sections for compound-nuclear reactions play an important role in models of astrophysical environments and simulations of the nuclear fuel cycle. Providing reliable cross section data remains a formidable task, and direct measurements have to be complemented by theoretical predictions and indirect methods. The surrogate nuclear reactions method provides an indirect approach for determining cross sections for reactions on unstable isotopes, which are difficult or impossible to measure otherwise. Current implementations of the method provide useful cross sections for (n,f) reactions, but need to be improved upon for applications to capture reactions.
Atlas of photoneutron cross sections obtained with monoenergetic photons
International Nuclear Information System (INIS)
Dietrich, S.S.; Berman, B.L.
1988-01-01
Photoneutron cross-section and integrated cross-section data obtained with monoenergetic photons are presented in a uniform format. All of the measured partial photoneutron cross sections, the total photoneutron cross section, and the photoneutron yield cross section are plotted as functions of the incident photon energy, as are the integrated photoneutron cross sections and their first and second moments. The values of the integrated cross sections and the moments of the integrated total cross section up to the highest photon energy for which they were measured are tabulated, as are the parameters of Lorentz curves fitted to the total photoneutron cross-section data for medium and heavy nuclei (A>50). This compilation is current as of June 1987. copyright 1988 Academic Press, Inc
Modeling neutrino-induced charged pion production on water at T2K kinematics
Nikolakopoulos, A.; González-Jiménez, R.; Niewczas, K.; Sobczyk, J.; Jachowicz, N.
2018-05-01
Pion production is a significant component of the signal in accelerator-based neutrino experiments. Over the last years, the MiniBooNE, T2K, and MINERvA collaborations have reported a substantial amount of data on (anti)neutrino-induced pion production on the nucleus. However, a comprehensive and consistent description of the whole data set is still missing. We aim at improving the current understanding of neutrino-induced pion production on the nucleus. To this end, the comparison of experimental data with theoretical predictions, preferably based on microscopic models, is essential to disentangle the different reaction mechanisms involved in the process. To describe single-pion production, we use a hybrid model that combines low- and a high-energy approaches. The low-energy model contains resonances and background terms. At high invariant masses, a high-energy model based on a Regge approach is employed. The model is implemented in the nucleus using the relativistic plane wave impulse approximation (RPWIA). We present a comparison of the hybrid-RPWIA and low-energy model with the recent neutrino-induced charged-current 1 π+ -production cross section on water reported by T2K. In order to judge the impact of final-state interactions (FSI), we confront our results with those of the nuwro Monte Carlo generator. The hybrid-RPWIA model and nuwro results compare favorably to the data, albeit that FSI are not included in the former. The need of a high-energy model at T2K kinematics is made clear. These results complement our previous work [Phys. Rev. D 97, 013004 (2018), 10.1103/PhysRevD.97.013004], in which we compared the models to the MINERvA and MiniBooNE 1 π+ data. The hybrid-RPWIA model tends to overpredict both the T2K and MINERvA data in kinematic regions where the largest suppression due to FSI is expected and agrees remarkably well with the data in other kinematic regions. On the contrary, the MiniBooNE data are underpredicted over the whole kinematic range.
Cross-Sectional Analysis of Longitudinal Mediation Processes.
O'Laughlin, Kristine D; Martin, Monica J; Ferrer, Emilio
2018-01-01
Statistical mediation analysis can help to identify and explain the mechanisms behind psychological processes. Examining a set of variables for mediation effects is a ubiquitous process in the social sciences literature; however, despite evidence suggesting that cross-sectional data can misrepresent the mediation of longitudinal processes, cross-sectional analyses continue to be used in this manner. Alternative longitudinal mediation models, including those rooted in a structural equation modeling framework (cross-lagged panel, latent growth curve, and latent difference score models) are currently available and may provide a better representation of mediation processes for longitudinal data. The purpose of this paper is twofold: first, we provide a comparison of cross-sectional and longitudinal mediation models; second, we advocate using models to evaluate mediation effects that capture the temporal sequence of the process under study. Two separate empirical examples are presented to illustrate differences in the conclusions drawn from cross-sectional and longitudinal mediation analyses. Findings from these examples yielded substantial differences in interpretations between the cross-sectional and longitudinal mediation models considered here. Based on these observations, researchers should use caution when attempting to use cross-sectional data in place of longitudinal data for mediation analyses.
The pion form factor from first principles
International Nuclear Information System (INIS)
Heide, J. van der
2004-01-01
We calculate the electromagnetic form factor of the pion in quenched lattice QCD. The non-perturbatively improved Sheikoleslami-Wohlert lattice action is used together with the O(a) improved current. We calculate form factor for pion masses down to mπ = 380 MeV. We compare the mean square radius for the pion extracted from our form factors to the value obtained from the 'Bethe Salpeter amplitude'. Using (quenched) chiral perturbation theory, we extrapolate our results towards the physical pion mass
Parametric equations for calculation of macroscopic cross sections
International Nuclear Information System (INIS)
Botelho, Mario Hugo; Carvalho, Fernando
2015-01-01
Neutronic calculations of the core of a nuclear reactor is one thing necessary and important for the design and management of a nuclear reactor in order to prevent accidents and control the reactor efficiently as possible. To perform these calculations a library of nuclear data, including cross sections is required. Currently, to obtain a cross section computer codes are used, which require a large amount of processing time and computer memory. This paper proposes the calculation of macroscopic cross section through the development of parametric equations. The paper illustrates the proposal for the case of macroscopic cross sections of absorption (Σa), which was chosen due to its greater complexity among other cross sections. Parametric equations created enable, quick and dynamic way, the determination of absorption cross sections, enabling the use of them in calculations of reactors. The results show efficient when compared with the absorption cross sections obtained by the ALPHA 8.8.1 code. The differences between the cross sections are less than 2% for group 2 and less than 0.60% for group 1. (author)
International Nuclear Information System (INIS)
Burleson, G.R.
1987-01-01
We are applying for a three-year grant from the US Department of Energy to New Mexico State University to continue its support of our work on experimental studies of nucleon-nucleon and pion-nucleus interactions at intermediate energies, which has been carried out in collaboration with groups from various laboratories and universities. The nucleon-nucleon work is aimed at making measurements that will contribute to a determination of the isospin-zero amplitudes, as well as continuing our investigations of evidence for dibaryon resonances. It is based at the LAMPF accelerator in Los Alamos, New Mexico. Current and planned experiments include measurements of total cross-section differences in pure spin states and of spin parameters in neutron-proton scattering. The pion-nucleus work is aimed at improving our understanding both of the nature of the pion-nucleus interaction and of nuclear structure. It consists of two programs, one based at LAMPF and one based principally at the SIN laboratory in Switzerland. The LAMPF-based work involves studies of large-angle scattering, double-charge-exchange scattering, including measurements at a new energy range above 300 MeV, and a new program of experiments with polarized nuclear targets. The SIN-based work involves studies of quasielastic scattering and absorption, including experiments with a new large-acceptance detector system planned for construction there. We are requesting support to continue the LAMPF-based work at its current level and to expand the SIN-based work to allow for increased involvement in experiments with the new detector system. 57 refs
Radiation quality of beams of negative pions
International Nuclear Information System (INIS)
Dicello, J.F.; Brenner, D.J.
1981-01-01
As a negative pion stops in tissue, it attaches itself to an adjacent atom to form a mesonic atom. Subsequently, the wave function of the pion interacts with that of the nucleus and the pion is absorbed. Because the energy associated with the rest mass of the pion is greater than the separation energy of the nuclear particles, the nucleus disintegrates (pion star). In tissue, approximately 40 MeV goes into overcoming the binding energies; 20 MeV goes into kinetic energy of charged particles; 80 MeV goes into kinetic energy of neutrons. In cases where biological studies are performed with beams of negative pions, as much as 20% of the total absorbed dose in the treatment volume and about 50% of the high-LET dose (> 100 keV/μm) can result from neutrons. The degree of biological response and the variation of that response throughout the treatment volume can be altered by the neutron dose
Exclusive production of pion pairs in {gamma}*{gamma} collisions at Large Q{sup 2}
Energy Technology Data Exchange (ETDEWEB)
Diehl, M.
2000-03-15
The authors perform a QCD analysis of the exclusive production of two mesons in {gamma}*{gamma} collisions in the kinematical domain of large photon virtuality Q and small hadronic invariant mass W. This reaction is dominated by a scale invariant mechanism which factorizes into a perturbative subprocess, {gamma}*{gamma} {r{underscore}arrow} q{anti q} or {gamma}*{gamma} {r{underscore}arrow} gg, and a generalized two-meson distribution amplitude. The authors develop in detail the phenomenology of this process at e{sup +}e{sup {minus}} colliders. Using a simple model for the two-pion distribution amplitude, based on its general properties, the authors estimate the cross section for the kinematics accessible at BABAR, BELLE, CLEO and LEP.
International Nuclear Information System (INIS)
Durwen, E.J.
1980-04-01
The differential cross section of the reaction γp->π + n was increased in 6 excitation curves at pion laboratory angles from thetasub(lab)sup(π) = 35 0 to 85 0 in 10 0 -steps. The γ-energy range extended from 0.3 GeV at thetasub(lab) = 35 0 to an angle-dependent maximum value which lied between 0.77 GeV at thetasub(lab)sup(π) = 35 0 and 1.94 GeV thetasub(lab)sup(π) = 85 0 . The 705 measuring points are part of a comprehensive measuring program of this laboratory which has the aim of the establishment of a complete, consistent high precision data set for the differential cross sections of the π + photoproduction in the resonance region. (orig./HSI) [de
Isoscalar single-pion production in the region of Roper and d⁎(2380 resonances
Directory of Open Access Journals (Sweden)
P. Adlarson
2017-11-01
Full Text Available Exclusive measurements of the quasi-free pn→ppπ− and pp→ppπ0 reactions have been performed by means of pd collisions at Tp=1.2 GeV using the WASA detector setup at COSY. Total and differential cross sections have been obtained covering the energy region Tp=0.95–1.3 GeV (s=2.3–2.46 GeV, which includes the regions of Δ(1232, N⁎(1440 and d⁎(2380 resonance excitations. From these measurements the isoscalar single-pion production has been extracted, for which data existed so far only below Tp=1 GeV. We observe a substantial increase of this cross section around 1 GeV, which can be related to the Roper resonance N⁎(1440, the strength of which shows up isolated from the Δ resonance in the isoscalar (NπI=0 invariant-mass spectrum. No evidence for a decay of the dibaryon resonance d⁎(2380 into the isoscalar (NNπI=0 channel is found. An upper limit of 180 μb (90% C.L. corresponding to a branching ratio of 9% has been deduced.
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.)
International Nuclear Information System (INIS)
Hasegawa, Akira
1991-01-01
A common group cross-section library has been developed in JAERI. This system is called 'JSSTDL-295n-104γ (neutron:295 gamma:104) group constants library system', which is composed of a common 295n-104γ group cross-section library based on JENDL-3 nuclear data file and its utility codes. This system is applicable to fast and fusion reactors. In this paper, firstly outline of group cross-section processing adopted in Prof. GROUCH-G/B system is described in detail which is a common step for all group cross-section library generation. Next available group cross-section libraries developed in Japan based on JENDL-3 are briefly reviewed. Lastly newly developed JSSTDL library system is presented with some special attention to the JENDL-3 data. (author)
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)
Neutron-capture cross sections from indirect measurements
Directory of Open Access Journals (Sweden)
Scielzo N.D.
2012-02-01
Full Text Available Cross sections for compound-nuclear reactions reactions play an important role in models of astrophysical environments and simulations of the nuclear fuel cycle. Providing reliable cross section data remains a formidable task, and direct measurements have to be complemented by theoretical predictions and indirect methods. The surrogate nuclear reactions method provides an indirect approach for determining cross sections for reactions on unstable isotopes, which are difficult or impossible to measure otherwise. Current implementations of the method provide useful cross sections for (n,f reactions, but need to be improved upon for applications to capture reactions.
Curves and tables of neutron cross sections
International Nuclear Information System (INIS)
Nakagawa, Tsuneo; Asami, Tetsuo; Yoshida, Tadashi
1990-07-01
Neutron cross-section curves from the Japanese Evaluated Nuclear Data Library version 3, JENDL-3, are presented in both graphical and tabular form for users in a wide range of application areas in the nuclear energy field. The contents cover cross sections for all the main reactions induced by neutrons with an energy below 20 MeV including; total, elastic scattering, capture, and fission, (n,n'), (n,2n), (n,3n), (n,α), (n,p) reactions. The 2200 m/s cross-section values, resonance integrals, and Maxwellian- and fission-spectrum averaged cross sections are also tabulated. (author)
Pion-nucleus forward scattering amplitudes at Δ(3,3) energies for π+---12C, 40Ca and 48Ca
International Nuclear Information System (INIS)
Dragoset, W.H. Jr.
1978-01-01
Using the LAMPF P 3 channel, small angle elastic cross sections and total cross sections were measured for π +- -- 12 C, 40 Ca and 48 Ca at incident pion kinetic energies spanning the energy region of the Δ(3,3) resonance. The sigma/sub EL/ experiment employed a spectrometer consisting of two magnets and six MWPC to measure scattering angles and momenta. For the sigma/sub T/ experiment six MWPC were positioned about the target in the beam to measure the deflection or absorption of the incident pions. Both experiments monitored the Jacobian cusp of the π → μ + ν decay to achieve absolute normalization. The two complementary data sets allowed the nuclear forward scattering amplitudes, f/sub N/(0), to be completely determined. The sigma/sub EL/ data were fit by a phenomenological small angle scattering model developed by Bethe and modified by West and Yennie. Due to the presence of nuclear-Coulomb interference in the elastic cross sections, both the magnitude and sign of Re f/sub N/ were determined by the fits. The Re f/sub N/ results were used in the sigma/sub T/ analysis to calculate corrections for the nuclear and nuclear-Coulomb interference amplitudes. Im f/sub N/ was calculated from the sigma/sub T/ results via the optical theorem. The overall self-consistencies of the data were checked by inserting IM f/sub N/ as a fixed parameter into the sigma/sub EL/ fits and comparing the resulting Re f/sub N/ to the original Re f/sub N/. It was determined that Re f/sub N/(0) has a zero near 180 MeV for both 12 C and 40 Ca. For 48 Ca, however, the Re f/sub N/ obtained by fitting with the West-Yennie formula was quite charge dependent and did not exhibit a zero in the energy range investigated. The differences in the 40 Ca, 48 Ca total cross sections were compared to a simple Kisslinger optical model calculation. The model indicated that the RMS neutron radius of 48 Ca exceeds the proton radius by 0.10 +- 0.06 fm
International Nuclear Information System (INIS)
Shuryak, E.V.
1990-01-01
Excited hadronic matter in the temperature interval T = 100-200 MeV is not an ideal pion gas, but ratehr a liquid, in which attractive interaction among particles plays an important role. Pion dispersion curve is in this case essentially modified by a kind of collective momentum-dependent potential, which becomes important as the quasipion comes to the boundary of the system. The author shows that these effects can provide an explanation for a number of recent experimental puzzles, in particular, for the observed copious production of soft pions and soft photons in high energy hadronic reactions
International Nuclear Information System (INIS)
Shuryak, E.V.
1990-04-01
Excited hadronic matter in the temperature interval T = 100--200 MeV is not an ideal pion gas, but rather a liquid, in which attractive interaction among particles plays an important role. Pion dispersion curve is in this case essentially modified by a kind of collective momentum-dependent potential, which becomes important as the ''quasipion'' comes to the boundary of the system. We show that effects can provide and explanation for a number of recent experimental puzzles, in particular, for the observed copious production of soft pions and soft photons in high energy hadronic reactions. 31 refs., 13 figs
Neutron Cross Sections for Aluminium
Energy Technology Data Exchange (ETDEWEB)
Forsberg, Leif
1963-08-15
Total, elastic, inelastic, (n, 2n), (n, {alpha}), (n, p), and (n, {gamma}) cross sections for aluminium have been compiled from thermal to 100 MeV based upon literature search and theoretical interpolations and estimates. Differential elastic cross sections in the centre of mass system are represented by the Legendre coefficients. This method was chosen in order to obtain the best description of the energy dependence of the anisotropy.
Energy Technology Data Exchange (ETDEWEB)
Loiacono, Laura Jean [Univ. of Texas, Austin, TX (United States)
2010-05-01
The Neutrinos at the Main Injector (NuMI) facility at Fermi National Accelerator Laboratory (FNAL) produces an intense muon neutrino beam used by the Main Injector Neutrino Oscillation Search (MINOS), a neutrino oscillation experiment, and the Main INjector ExpeRiment v-A, (MINERv A), a neutrino interaction experiment. Absolute neutrino cross sections are determined via σ_{v} = N _{v}/Φ_{v} , where the numerator is the measured number of neutrino interactions in the MINOS Detector and the denominator is the flux of incident neutrinos. Many past neutrino experiments have measured relative cross sections due to a lack of precise measurements of the incident neutrino flux, normalizing to better established reaction processes, such as quasielastic neutrino-nucleon scattering. But recent measurements of neutrino interactions on nuclear targets have brought to light questions about our understanding of nuclear effects in neutrino interactions. In this thesis the v_{μ} inclusive charged current cross section on iron is measured using the MINOS Detector. The MINOS detector consists of alternating planes of steel and scintillator. The MINOS detector is optimized to measure muons produced in charged current v_{μ} interactions. Along with muons, these interactions produce hadronic showers. The neutrino energy is measured from the total energy the particles deposit in the detector. The incident neutrino flux is measured using the muons produced alongside the neutrinos in meson decay. Three ionization chamber monitors located in the downstream portion of the NuMI beamline are used to measure the muon flux and thereby infer the neutrino flux by relation to the underlying pion and kaon meson flux. This thesis describes the muon flux instrumentation in the NuMI beam, its operation over the two year duration of this measurement, and the techniques used to derive the neutrino flux.
High ET jet cross sections at CDF
International Nuclear Information System (INIS)
Flaugher, B.
1996-08-01
The inclusive jet cross section for p anti p collisions at √s = 1.8 TeV as measured by the CDF collaboration will be presented. Preliminary CDF measurements of the Σ E T cross section at √s = 1.8 TeV and the central inclusive jet cross section at √s = 0.630 TeV will also be shown
International Nuclear Information System (INIS)
Eickhoff, W.
2003-05-01
Absolute, differential 4 He(e,e'p), (e,e'pp), and (e,e'dp) cross-sections in extended kinematical regions which are corresponding to the 'dip' between the quasielastic and the Δ-resonance peak in the 4 He(e,e') response-function have been measured at the high duty factor Electron Stretcher Accelerator ELSA of Bonn University. The scattered electrons were detected with a magnetic spectrometre, the hadrons with two sets of large-area plastic-scintillator telescopes. The measured cross-sections indicate important contributions from reactions on correlated nuclear pairs. In the 4 H(e,e'p) cross-sections the two-body break-up, 4 He(e,e'p)t, and the quasifree production of pions are visible as well. On the assumption of the Impulse-Approximation momentum-density distribution of the proton in 4 He have been derived from the measured cross-sections of the two-body and of the continuum break-up of the 4 He nucleus. (orig.)
Pion distribution in the nucleon
International Nuclear Information System (INIS)
Lee, T.-S.H.
1989-01-01
A model is presented for calculating the pion wave function inside the nucleon. By assuming that all pions around a core of the nucleon are in the lowest eigenstate of the system, it is shown that both the bound state and πN scattering amplitude can be consistently described by an exactly soluble model defined in the subspace spanned by the core state and the physical πN state. The parameters of the model are determined by fitting the data of the nucleon mass, πNN coupling constant and low energy πN scattering phase shifts. The model predicts that the probability of finding the pion component inside the nucleon is about 20%. The calculated πNN form factor differs significantly from the conventional monopole form. The dynamical consequences of the differences are demonstrated in a calculation of electromagnetic production of pions from the nucleon and the deuteron. 7 refs., 4 figs., 1 tab
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
Measuring pion beta decay with high-energy pion beams
International Nuclear Information System (INIS)
McFarlane, W.K.; Hoffman, C.M.
1993-01-01
Improved measurements of the pion beta decay rate are possible with an intense high-energy pion beam. The rate for the decay π + → π 0 e + vε is predicted by the Standard Model (SM) to be R(π + → π 0 e + vε) = 0.3999±0.0005 s -1 . The best experimental number, obtained using in-flight decays, is R(π + → π 0 e + vε) = 0.394 ± 0.015 s -1 . A precise measurement would test the SM by testing the unitarity of the Cabibbo-Kobayashi-Maskawa matrix for which one analysis of the nuclear beta decay data has shown a 0.4% discrepancy. Several nuclear correction factors, needed for nuclear decay, are not present for pion beta decay, so that an experiment at the 0.2% level would be a significant one. Detailed study of possible designs will be needed, as well as extensive testing of components. The reduction of systematic errors to the 0.1% level can only be done over a period of years with a highly stable apparatus and beam. At a minimum, three years of occupancy of a beam line, with 800 hours per year, would be required
Recommended evaluation procedure for photonuclear cross section
Energy Technology Data Exchange (ETDEWEB)
Lee, Young-Ouk; Chang, Jonghwa; Fukahori, Tokio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment
1998-03-01
In order to generate photonuclear cross section library for the necessary applications, data evaluation is combined with theoretical evaluation, since photonuclear cross sections measured cannot provide all necessary data. This report recommends a procedure consisting of four steps: (1) analysis of experimental data, (2) data evaluation, (3) theoretical evaluation and, if necessary, (4) modification of results. In the stage of analysis, data obtained by different measurements are reprocessed through the analysis of their discrepancies to a representative data set. In the data evaluation, photonuclear absorption cross sections are evaluated via giant dipole resonance and quasi-deutron mechanism. With photoabsorption cross sections from the data evaluation, theoretical evaluation is applied to determine various decay channel cross sections and emission spectra using equilibrium and preequilibrium mechanism. After this, the calculated results are compared with measured data, and in some cases the results are modified to better describe measurements. (author)
Pion production and fragmentation of nuclei in high energy nucleus-nucleus collisions
International Nuclear Information System (INIS)
Oskarsson, A.
1983-01-01
In collisions between nuclei at high energies one can study the behaviour of nuclear matter under extreme conditions, regarding nuclear density and temperature. The Bevalac and the CERN SC beams have been used and nuclear emulsion and scintillation telescopes have measured the reaction products. Collisions at 50A-200A MeV and at 2A GeV have been investigated. Proton spectra from 12 C induced reactions at 85A MeV have been recorded for different targets. Energetic protons at large angles can be assumed to be emitted from a source moving with half the beam velocity and a temperature between 13 and 17 MeV, depending on the target. In collisions between nuclei, pions can be produced below 290A MeV due to the internal Fermi motion of the nucleons. Subthreshold pion production has been studied for 12 C induced reactions at 85A and 75A Mev. The cross-sections are consistent with a quasi-free nucleon-nucleon scattering picture, involving Fermi motion, Pauli blocking and pion reabsorption. 16 C induced reactions in emulsion have been studied at 75A, 175A and 2000A MeV. It is shown that the excitation of the parts of the nuclei which are not overlapping (the spectators) increases with the beam energy. The 16 O projectile frequently breaks up into multiple He fragments. These events are associated with large impact parameters. Central collisions with Ag, Br target at 50A-110A MeV have been analysed separately. It is shown that the momentum transfer to the target nucleus is limited to a value considerably lower than the full momentum transfer in a fusion reactions. Events are observed where there are numerous fragments with 3< Z<8. These multifragmentation events cannot be understood in a thermal approach. (author)
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
Nucleon multiplicities after pion absorption in 160
International Nuclear Information System (INIS)
Hamers, R.
1989-01-01
The experiment described in this thesis concerns a simultaneous measurement of two- and higher-fold coincidences following positive and negative pion absorption in 16 0. The detected particles are protons, neutrons and deuterons. The detection and analysis of charged particles is discussed. The incident pion energy was 65 MeV, thus well below the delta resonance. The low pion energy was 65 MeV, thus well below the delta resonance. The low pion energy ensures that contributions of initial state interactions, i.e. pion-nucleon scattering preceding absorption, are minimized. The following reaction channels were selected and analyzed: π + ,pp), (π + ,pd). Evidence for quasifree reaction precessed has been investigated by comparing the data with phase-space calculations incorporating the geometry of the experimental setup. (author). 36 refs.; 1 figs.; 3 tabs
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
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
Energy Technology Data Exchange (ETDEWEB)
Mattione, P. T.; Carman, D. S.; Strakovsky, I. I.; Workman, R. L.; Kudryavtsev, A. E.; Svarc, A.; Tarasov, V. E.; Adhikari, K. P.; Adhikari, S.; Adikaram, D.; Akbar, Z.; Anefalos Pereira, S.; Ball, J.; Baltzell, N. A.; Bashkanov, M.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A. S.; Boiarinov, S.; Briscoe, W. J.; Burkert, V. D.; Cao, T.; Celentano, A.; Charles, G.; Chetry, T.; Ciullo, G.; Clark, L.; Cole, P. L.; Contalbrigo, M.; Cortes, O.; Crede, V.; D' Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Defurne, M.; Deur, A.; Djalali, C.; Dugger, M.; Dupre, R.; Egiyan, H.; El Alaoui, A.; El Fassi, L.; Eugenio, P.; Fedotov, G.; Fersch, R.; Filippi, A.; Fleming, J. A.; Fradi, A.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Gleason, C.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Hattawy, M.; Heddle, D.; Hicks, K.; Hollis, G.; Holtrop, M.; Hughes, S. M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jenkins, D.; Jiang, H.; Jo, H. S.; Joo, K.; Joosten, S.; Keller, D.; Khachatryan, G.; Khachatryan, M.; Khandaker, M.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Kubarovsky, V.; Kuleshov, S. V.; Lanza, L.; Lenisa, P.; Livingston, K.; MacGregor, I. J. D.; Markov, N.; McKinnon, B.; Meyer, C. A.; Meziani, Z. E.; Mineeva, T.; Mokeev, V.; Montgomery, R. A.; Movsisyan, A.; Munoz Camacho, C.; Murdoch, G.; Nadel-Turonski, P.; Net, L. A.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Paolone, M.; Paremuzyan, R.; Park, K.; Pasyuk, E.; Phelps, W.; Pisano, S.; Pogorelko, O.; Price, J. W.; Procureur, S.; Prok, Y.; Protopopescu, D.; Raue, B. A.; Ripani, M.; Ritchie, B. G.; Rizzo, A.; Rosner, G.; Sabatié, F.; Salgado, C.; Schumacher, R. A.; Sharabian, Y. G.; Simonyan, A.; Skorodumina, Iu.; Smith, G. D.; Sokhan, D.; Sparveris, N.; Stankovic, I.; Stepanyan, S.; Strauch, S.; Taiuti, M.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D.; Wei, X.; Wood, M. H.; Zachariou, N.; Zhang, J.; Zhao, Z. W.
2017-09-01
The quasifree gamma d -> pi(-)p(p) differential cross section has been measured with CLAS at photon beam energies E-gamma from 0.445 to 2.510 GeV (corresponding to W from 1.311 to 2.366 GeV) for pion center-of-mass angles cos theta(c.m.)(pi) from -0.72 to 0.92. A correction for final state interactions has been applied to these data to extract the gamma n -> pi(-)p differential cross sections. These cross sections are quoted in 8428 (E-gamma, cos theta(c.m)(pi)) bins, a factor of nearly 3 increase in the world statistics for this channel in this kinematic range. These new data help to constrain coupled-channel analysis fits used to disentangle the spectrum of N* resonances and extract their properties. Selected photon decay amplitudes N* -> gamma n at the resonance poles are determined for the first time and are reported here.
Recommended activation detector cross sections (RNDL-82)
International Nuclear Information System (INIS)
Bondars, Kh.Ya.; Lapenas, A.A.
1984-01-01
The results of the comparison between measured and calculated average cross sections in 5 benchmark experiments are presented. Calculations have been based on the data from 10 libraries of evaluated cross sections. The recommended library (RNDL-82) of the activation detector cross sections has been created on the basis of the comparison. RNDL-82, including 26 reactions, and the basic characteristics of the detectors are presented. (author)
Activation cross section and isomeric cross section ratios for the (n ,2 n ) reaction on 153Eu
Luo, Junhua; Jiang, Li; Li, Suyuan
2017-10-01
The 153Eu(n ,2 n ) m1,m2,g152Eu cross section was measured by means of the activation technique at three neutron energies in the range 13-15 MeV. The quasimonoenergetic neutron beam was formed via the 3H(d ,n ) 4He reaction, in the Pd-300 Neutron Generator at the Chinese Academy of Engineering Physics (CAEP). The activities induced in the reaction products were measured using high-resolution γ-ray spectroscopy. The cross section of the population of the second high-spin (8-) isomeric state was measured along with the reaction cross section populating both the ground (3-) and the first isomeric state (0-). Cross sections were also evaluated theoretically using the numerical code TALYS-1.8, with different level density options at neutron energies varying from the reaction threshold to 20 MeV. Results are discussed and compared with the corresponding literature.
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.)
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.)
Activation cross section and isomeric cross-section ratio for the (n,2n) reaction on {sup 132,134}Ba
Energy Technology Data Exchange (ETDEWEB)
Luo, Junhua [Hexi Univ., Zhangye (China). School of Physics and Electromechanical Engineering; Hexi Univ., Zhangye (China). Inst. of New Energy; Wu, Chunlei; Jiang, Li [Chinese Academy of Engineering Physics, Mianyang (China). Inst. of Nuclear Physics and Chemistry; Li, Suyuan [Hexi Univ., Zhangye (China). Inst. of New Energy
2017-07-01
Cross sections of the {sup 132}Ba(n,2n){sup 131m,g}Ba and {sup 134}Ba(n,2n){sup 133m,g}Ba reactions and their isomeric cross section ratios σ{sub m}/σ{sub g} have been measured by means of the activation technique at three neutron energies in the range 13-15 MeV. BaCO{sub 3} samples and Nb monitor foils were activated together to determine the reaction cross section and the incident neutron flux. The quasimonoenergetic neutrons beam were produced via the {sup 3}H(d,n){sup 4}He reaction at the Pd-300 Neutron Generator of the Chinese Academy of Engineering Physics (CAEP). The activities induced in the reaction products were measured using high-resolution γ ray spectroscopy. The pure cross section of the ground-state was derived from the absolute cross section of the metastable state and the residual nuclear decay analysis. Cross sections were also evaluated theoretically using the numerical nuclear model code, TALYS-1.8 with different level density options at neutron energies varying from the reaction threshold to 20 MeV. Results are discussed and compared with the corresponding literature.
The pion electromagnetic form factor in the time-like energy range 1.35≤√s≤2.4 GeV
International Nuclear Information System (INIS)
1988-10-01
The e + e - → π + π - cross section has been measured from about 280 events (an order of magnitude more than the previous world statistics) in the energy interval 1.35≤√s≤2.4 GeV with the DM2 detector at DCI. The pion squared form factor shows a deep minimum around 1.6 GeV/c 2 and is best fit under the hypothesis of two ρ like resonances ≅ 0.2 GeV/c 2 wide with 1.43 and 1.76 GeV/c 2 masses
Pion-nucleus scatter and the Pauli principle
International Nuclear Information System (INIS)
Dover, C.B.; Lemmer, R.H.
1976-01-01
A density expansion of the pion self-energy for pions in nuclear matter is reexamined. It is shown that a single hole-line expansion of the self-energy (i) is equivalent to using a strongly quenched πN scattering amplitude in the medium, and (ii) results in an inconsistent treatment of the virtual pions necessarily present in a field-theoretic description of the problem. Exchange of intermediate pions gives rise to nucleon-nucleon, as well as pion-nucleon scattering diagrams that both contribute to the pion self-energy in an essential way. The nucleon-nucleon scattering proceeds, for instance, via a one-pion-exchange potential that is, however, highly nonstatic for energy transfers between nucleons close to the incident energy. Such interactions are singled out automatically for special treatment in a field-theory approach to the problem, and should not be introduced in an ad hoc manner as part of an empirical NN interaction in nuclear matter. We evaluate the coherent and charge exchange contributions to the pion-nucleus optical potential, proportional to the total density and the neutron-proton density difference, respectively. The Pauli principle is found to provide a small correction to the coherent part, both in the hole-line and density expansion formalisms. However, the charge exchange part of the potential is almost completely damped at low energies in the hole-line expansion, while the inclusion of backward-going graphs (random-phase-approximation-type correlations) restores it to its value based on free space πN charge exchange amplitudes (i.e., no net Pauli effect)
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.
Dielectronic recombination cross sections for H-like ions
International Nuclear Information System (INIS)
Pindzola, M.S.; Badnell, N.R.; Griffin, D.C.
1990-01-01
Dielectronic recombination cross sections for several H-like atomic ions are calculated in an isolated-resonance, distorted-wave approximation. Fine-structure and configuration-interaction effects are examined in detail for the O 7+ cross section. Hartree-Fock, intermediate-coupled, multiconfiguration dielectronic recombination cross sections for O 7+ are then compared with the recent experimental measurements obtained with the Test Storage Ring in Heidelberg. The cross-section spectra line up well in energy and the shape of the main resonance structures are comparable. The experimental integrated cross sections differ by up to 20% from theory, but this may be due in part to uncertainties in the electron distribution function
Comparative analysis among several cross section sets
International Nuclear Information System (INIS)
Caldeira, A.D.
1983-01-01
Critical parameters were calculated using the one dimensional multigroup transport theory for several cross section sets. Calculations have been performed for water mixtures of uranium metal, plutonium metal and uranium-thorium oxide, and for metallics systems, to determine the critical dimensions of geometries (sphere and cylinder). For this aim, the following cross section sets were employed: 1) multigroup cross section sets obtained from the GAMTEC-II code; 2) the HANSEN-ROACH cross section sets; 3) cross section sets from the ENDF/B-IV, processed by the NJOY code. Finally, we have also calculated the corresponding critical radius using the one dimensional multigroup transport DTF-IV code. The numerical results agree within a few percent with the critical values obtained in the literature (where the greatest discrepancy occured in the critical dimensions of water mixtures calculated with the values generated by the NJOY code), a very good results in comparison with similar works. (Author) [pt
a Kinematically Complete Measurement of Positive Pion Production from Protons Near Threshold.
Hardie, John George
The total cross section for the reaction pp to pnpi^+ was measured at 294, 300, 307, 314, and 320 MeV. Angular distributions for the same reaction were measured at 294, 300 and 320 MeV. This is the first measurement of this reaction channel within 50 MeV of threshold. Study of pion production near threshold allows examination of the short range parts of the NN interaction, particularly the non-resonant partial waves. The data indicates that the contribution of p-waves to the pp to pnpi^+ reaction remains smaller than 20% up to 320 MeV. The total cross section data is compared to the theoretical calculations of Schillaci, Silbar and Young (1969) and Lee and Matsuyama (1987). Both reproduce some features of the data, but neither theory completely explains all the features of the data. There are no angular distribution predictions for comparison, but the data is symmetric around 90 degrees and appears to follow a 1+bcos^2theta _pi distribution, with the parameter b being consistent with zero for 294 MeV, about 0.05 at 300 MeV and about 0.18 at 320 MeV. This indicates that the higher partial waves are still weak at 320 MeV, although they are beginning to come into the reaction.
International Nuclear Information System (INIS)
Kligerman, M.M.
1975-01-01
Results are summarized from studies on the relative biological effects as compared with x or γ radiation and OER of negative pi mesons produced by the Berkeley 184-inch synchrocyclotron or the NIMROD 7-GeV proton synchrocyclotron at the Rutherford High Energy Laboratory in England using cultured animal cells or Vicia faba cells as the test system. Preliminary results are reported from similar radiobiological studies at the Los Alamos Meson Physics Facility. The relative response of human tissues to peak pion irradiation was compared with 140 kV x rays in a single patient with multiple malignant melanoma by observing the acute response of the skin surrounding metastatic modules following exposure to either pions or x radiation. Color photographs of the irradiated areas made at least twice weekly and densitometry measurements and observations by radiation therapists indicated that maximum erythemia occurred during the fifth, sixth, or seventh week after the start of a schedule of fractionated exposure to 15 fractions over 19 elapsed days. X irradiation was delivered at a dose rate of 500 rads/min to modules to deliver 55, 66, or 75 percent of a skin surface dose of 5,200 rads and pion irradiation, at doses numerically 50 percent of the x ray dose, was delivered at a dose rate of 5 to 7 rads/min. Dose response curves were plotted. Results of histological examinations of skin samples taken 24 weeks following irradiation are reported. Results are discussed relative to the destruction of melanoma cells following pion or x ray treatment
Fission cross section measurements at intermediate energies
International Nuclear Information System (INIS)
Laptev, Alexander
2005-01-01
The activity in intermediate energy particle induced fission cross-section measurements of Pu, U isotopes, minor actinides and sub-actinides in PNPI of Russia is reviewed. The neutron-induced fission cross-section measurements are under way in the wide energy range of incident neutrons from 0.5 MeV to 200 MeV at the GNEIS facility. In number of experiments at the GNEIS facility, the neutron-induced fission cross sections were obtained for many nuclei. In another group of experiments the proton-induced fission cross-section have been measured for proton energies ranging from 200 to 1000 MeV at 100 MeV intervals using the proton beam of PNPI synchrocyclotron. (author)
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.
Scattering of low-energetic pions on the sulfur isotopes 32S and 34S
International Nuclear Information System (INIS)
Krell, S.
1990-01-01
At the Paul-Scherrer Institute PSI in Villingen/Switzerland the scattering of positive and negative pions of 50 MeV kinetic energy on the sulfur isotopes 32 S, 34 S was measured with the new installed low-energy pion spectrometer LEPS. Elastic cross sections were measured for scattering angles of 5deg-123deg for both pion polarities and for both isotopes. Because of the good resolution of 500 keV it was also possible to measure the inelastic scattering to single excited nuclear states of 45deg-123deg. Aim of the analyses was the testing of the basing reaction model, the test of the effective pion-nucleon interaction in the nucleus, as well as the extraction of neutron density distributions and neutron transition densities in 34 S. At the N=Z nucleus 32 S, the nuclear structure of which is known from the electron scattering, by means of the elastic scattering the effective πN interaction was fixed. The validity of the impulse approximation at 50 MeV was proved by the quantitative reproduction of the 2 1 + scattering data on 32 S by parameter-free DWIA calculations. For the 4 1 + and the 3 1 + excitations in 32 S the expected isoscalar character was confirmed. For the nucleus 34 S the analysis of the eleastic scattering yields a neutron skin of Δr np =0.03(1)fm. The scattering to the 2 1 + yields a neutron moment of M n =16.6(10)efm 2 respectively a ratio of proton to neutron moment of M n /M p =1.19(9), which corresponds to a collective isoscalar excitation. Against this for the 2 2 + excitation a ratio for the moments of M n /M p =-0.4(2) is determined, what means that to this not collective, proton-dominated excitation neutron and proton wave functions contribute antiphasically, as it is typical for isovectorial excitations. (orig./HSI) [de
Partial cross sections near the higher resonances
International Nuclear Information System (INIS)
Falk-Vairant, P.; Valladas, G.
1961-07-01
As a continuation of the report given at the 10. Rochester Conference, recent measurements of charge-exchange cross section and π 0 production in π - -p interactions are presented here. Section 1 gives a summary of the known results for the elastic, inelastic, and charge-exchange cross sections. Section 2 presents the behavior of the cross sections in the T=1/2 state, in order to discuss the resonances at 600 and 890 MeV. Section 3 discusses the charge-exchange scattering and the interference term between the T=1/2 and T=3/2 states. Section 4 presents some comments on inelastic processes. This report is reprinted from 'Reviews of Modern Physics', Vol. 33, No. 3, 362-367, July, 1961
International Nuclear Information System (INIS)
Kondratyuk, S.; Kubodera, K.; Myhrer, F.; Scholten, O.
2004-01-01
The Adler-Weisberger and Goldberger-Miyazawa-Oehme sum rules are calculated within a relativistic, unitary and crossing symmetric dynamical model for pion-nucleon scattering using two different methods: (1) by evaluating the scattering amplitude at the corresponding low-energy kinematics and (2) by evaluating the sum-rule integrals with the calculated total cross section. The discrepancy between the results of the two methods provides a measure of the breaking of analyticity and chiral symmetry in the model. The contribution of the Δ resonance, including its dressing with meson loops, is discussed in some detail and found to be small
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...
Classical scattering cross section in sputtering transport theory
International Nuclear Information System (INIS)
Zhang Zhulin
2002-01-01
For Lindhard scaling interaction potential scattering commonly used in sputtering theory, the authors analyzed the great difference between Sigmund's single power and the double power cross sections calculated. The double power cross sections can give a much better approximation to the Born-Mayer scattering in the low energy region (m∼0.1). In particular, to solve the transport equations by K r -C potential interaction given by Urbassek few years ago, only the double power cross sections (m∼0.1) can yield better approximate results for the number of recoils. Therefore, the Sigmund's single power cross section might be replaced by the double power cross sections in low energy collision cascade theory
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.
Cross section data for ionization of important cyanides
International Nuclear Information System (INIS)
Kaur, Jaspreet; Antony, Bobby
2015-01-01
Highlights: • Multi centre spherical complex optical potential formalism used to find the CS. • Effective method (CSP-ic) to derive ionization contribution from inelastic CS. • Result shows excellent accord with previous results and consistent behaviour. • Maiden attempt to find CS for many cyanide molecules. • Strong correlation observed between peak of ionization with target properties. - Abstract: This article presents cross section calculations for interactions of important cyanides with electrons possessing energies beginning from ionization threshold of the target molecule to 5 keV. These data are pursued to meet the ever increasing demand for cross sections by the relevant atomic and molecular community for modelling astrophysical, atmospheric and technological domains. The calculations have been executed using an amalgam of multi centre spherical complex optical potential (MSCOP) formalism and complex scattering potential-ionization contribution (CSP-ic) method. Cross sections are compared with experimental and theoretical data wherever available. Strong correlations are observed for the cross sections which affirms consistent and reliable cross sections. Isomeric effect has been interpreted using variation of cross section with structure and target properties. Our cross sections will be tabulated in atomic collision database for use in modelling various statistical and dynamical quantities.
Cross section data for ionization of important cyanides
Energy Technology Data Exchange (ETDEWEB)
Kaur, Jaspreet; Antony, Bobby, E-mail: bka.ism@gmail.com
2015-11-15
Highlights: • Multi centre spherical complex optical potential formalism used to find the CS. • Effective method (CSP-ic) to derive ionization contribution from inelastic CS. • Result shows excellent accord with previous results and consistent behaviour. • Maiden attempt to find CS for many cyanide molecules. • Strong correlation observed between peak of ionization with target properties. - Abstract: This article presents cross section calculations for interactions of important cyanides with electrons possessing energies beginning from ionization threshold of the target molecule to 5 keV. These data are pursued to meet the ever increasing demand for cross sections by the relevant atomic and molecular community for modelling astrophysical, atmospheric and technological domains. The calculations have been executed using an amalgam of multi centre spherical complex optical potential (MSCOP) formalism and complex scattering potential-ionization contribution (CSP-ic) method. Cross sections are compared with experimental and theoretical data wherever available. Strong correlations are observed for the cross sections which affirms consistent and reliable cross sections. Isomeric effect has been interpreted using variation of cross section with structure and target properties. Our cross sections will be tabulated in atomic collision database for use in modelling various statistical and dynamical quantities.
Accurate Cross Sections for Microanalysis
Rez, Peter
2002-01-01
To calculate the intensity of x-ray emission in electron beam microanalysis requires a knowledge of the energy distribution of the electrons in the solid, the energy variation of the ionization cross section of the relevant subshell, the fraction of ionizations events producing x rays of interest and the absorption coefficient of the x rays on the path to the detector. The theoretical predictions and experimental data available for ionization cross sections are limited mainly to K shells of a...
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)
The two-nucleon system above pion threshold
International Nuclear Information System (INIS)
Poepping, H.; Sauer, P.U.; Zhang Xizhen
1987-01-01
A force model is presented for the description of the two-nucleon system below and above pion threshold and its coupled inelastic channels with one pion. It uses Δ-isobar and pion degrees of freedom in addition to the nucleonic one. The force model is based on a hamiltonian approach within the framework of noncovariant quantum mechanics. It extends the traditional approach with purely nucleonic potentials in isospin-triplet partial waves. It is constructed to remain valid up to 500 MeV c.m. energy. The characteristics of the force model is its mechanism for pion production and pion absorption which is mediated by the Δ-isobar. Even without any fit of phenomenological parameters the force model is able to account for the experimental data of elastic nucleon-nucleon scattering' of the inelastic reactions pp ↔ π + d and of elastic pion-deuteron scattering with satisfactory accuracy. No need for the introduction of dibaryon degrees of freedom has been found yet. The force model is a realistic one in the two-nucleon system. In many-nucleon systems it forms the unifying basis for a microscopic description of nuclear structure and nuclear reactions at low and intermediate energies. (orig.)
Criticality benchmark comparisons leading to cross-section upgrades
International Nuclear Information System (INIS)
Alesso, H.P.; Annese, C.E.; Heinrichs, D.P.; Lloyd, W.R.; Lent, E.M.
1993-01-01
For several years criticality benchmark calculations with COG. COG is a point-wise Monte Carlo code developed at Lawrence Livermore National Laboratory (LLNL). It solves the Boltzmann equation for the transport of neutrons and photons. The principle consideration in developing COG was that the resulting calculation would be as accurate as the point-wise cross-sectional data, since no physics computational approximations were used. The objective of this paper is to report on COG results for criticality benchmark experiments in concert with MCNP comparisons which are resulting in corrections an upgrades to the point-wise ENDL cross-section data libraries. Benchmarking discrepancies reported here indicated difficulties in the Evaluated Nuclear Data Livermore (ENDL) cross-sections for U-238 at thermal neutron energy levels. This led to a re-evaluation and selection of the appropriate cross-section values from several cross-section sets available (ENDL, ENDF/B-V). Further cross-section upgrades anticipated
Pion broadening and low-mass dilepton production
International Nuclear Information System (INIS)
Schulze, H.-J.; Blaschke, D.
2002-01-01
Mass and transverse momentum spectra of dileptons produced in Pb + Au (158 GeV/u) collisions within a pion annihilation model are determined. A fit to the data requires simultaneous mass reduction and broadening of the in-medium rho propagator. The introduction of a finite pion width, as required within self-consistent approaches to the interacting pion gas, further improves the agreement with the data
Pion interferometric tests of transport models
Energy Technology Data Exchange (ETDEWEB)
Padula, S.S.; Gyulassy, M.; Gavin, S. (Lawrence Berkeley Lab., CA (USA). Nuclear Science Div.)
1990-01-08
In hadronic reactions, the usual space-time interpretation of pion interferometry often breaks down due to strong correlations between spatial and momentum coordinates. We derive a general interferometry formula based on the Wigner density formalism that allows for arbitrary phase space and multiparticle correlations. Correction terms due to intermediate state pion cascading are derived using semiclassical hadronic transport theory. Finite wave packets are used to reveal the sensitivity of pion interference effects on the details of the production dynamics. The covariant generalization of the formula is shown to be equivalent to the formula derived via an alternate current ensemble formalism for minimal wave packets and reduces in the nonrelativistic limit to a formula derived by Pratt. The final expression is ideally suited for pion interferometric tests of Monte Carlo transport models. Examples involving gaussian and inside-outside phase space distributions are considered. (orig.).
Pion interferometric tests of transport models
International Nuclear Information System (INIS)
Padula, S.S.; Gyulassy, M.; Gavin, S.
1990-01-01
In hadronic reactions, the usual space-time interpretation of pion interferometry often breaks down due to strong correlations between spatial and momentum coordinates. We derive a general interferometry formula based on the Wigner density formalism that allows for arbitrary phase space and multiparticle correlations. Correction terms due to intermediate state pion cascading are derived using semiclassical hadronic transport theory. Finite wave packets are used to reveal the sensitivity of pion interference effects on the details of the production dynamics. The covariant generalization of the formula is shown to be equivalent to the formula derived via an alternate current ensemble formalism for minimal wave packets and reduces in the nonrelativistic limit to a formula derived by Pratt. The final expression is ideally suited for pion interferometric tests of Monte Carlo transport models. Examples involving gaussian and inside-outside phase space distributions are considered. (orig.)
Cross section homogenization analysis for a simplified Candu reactor
International Nuclear Information System (INIS)
Pounders, Justin; Rahnema, Farzad; Mosher, Scott; Serghiuta, Dumitru; Turinsky, Paul; Sarsour, Hisham
2008-01-01
The effect of using zero current (infinite medium) boundary conditions to generate bundle homogenized cross sections for a stylized half-core Candu reactor problem is examined. Homogenized cross section from infinite medium lattice calculations are compared with cross sections homogenized using the exact flux from the reference core environment. The impact of these cross section differences is quantified by generating nodal diffusion theory solutions with both sets of cross sections. It is shown that the infinite medium spatial approximation is not negligible, and that ignoring the impact of the heterogeneous core environment on cross section homogenization leads to increased errors, particularly near control elements and the core periphery. (authors)
Fission cross section measurements of actinides at LANSCE
Energy Technology Data Exchange (ETDEWEB)
Tovesson, Fredrik [Los Alamos National Laboratory; Laptev, Alexander B [Los Alamos National Laboratory; Hill, Tony S [INL
2010-01-01
Fission cross sections of a range of actinides have been measured at the Los Alamos Neutron Science Center (LANSCE) in support of nuclear energy applications. By combining measurement at two LANSCE facilities, Lujan Center and the Weapons Neutron Research center (WNR), differential cross sections can be measured from sub-thermal energies up to 200 MeV. Incident neutron energies are determined using the time-of-flight method, and parallel-plate ionization chambers are used to measure fission cross sections relative to the {sup 235}U standard. Recent measurements include the {sup 233,238}U, {sup 239,242}Pu and {sup 243}Am neutron-induced fission cross sections. In this paper preliminary results for cross section data of {sup 243}Am and {sup 233}U will be presented.
Landau-Migdal parameters and pion condensation
Energy Technology Data Exchange (ETDEWEB)
Tatsumi, Toshitaka [Department of Physics, Kyoto Univ., Kyoto (Japan)
1999-08-01
The possibility of pion condensation, one of the long-standing issues in nuclear physics, is reexamined in the light of the recent experimental data on the giant Gamow-Teller resonance. The experimental result tells that the coupling of nucleon particle-hole states with {delta} isobar-hole states in the spin-isospin channel should be weaker than that previously believed. It, in turn, implies that nuclear matter has the making of pion condensation at low densities. The possibility and implications of pion condensation in the heavy-ion collisions and neutron stars should be seriously reconsidered. (author)
Methodology series module 3: Cross-sectional studies
Directory of Open Access Journals (Sweden)
Maninder Singh Setia
2016-01-01
Full Text Available Cross-sectional study design is a type of observational study design. In a cross-sectional study, the investigator measures the outcome and the exposures in the study participants at the same time. Unlike in case–control studies (participants selected based on the outcome status or cohort studies (participants selected based on the exposure status, the participants in a cross-sectional study are just selected based on the inclusion and exclusion criteria set for the study. Once the participants have been selected for the study, the investigator follows the study to assess the exposure and the outcomes. Cross-sectional designs are used for population-based surveys and to assess the prevalence of diseases in clinic-based samples. These studies can usually be conducted relatively faster and are inexpensive. They may be conducted either before planning a cohort study or a baseline in a cohort study. These types of designs will give us information about the prevalence of outcomes or exposures; this information will be useful for designing the cohort study. However, since this is a 1-time measurement of exposure and outcome, it is difficult to derive causal relationships from cross-sectional analysis. We can estimate the prevalence of disease in cross-sectional studies. Furthermore, we will also be able to estimate the odds ratios to study the association between exposure and the outcomes in this design.
Methodology Series Module 3: Cross-sectional Studies.
Setia, Maninder Singh
2016-01-01
Cross-sectional study design is a type of observational study design. In a cross-sectional study, the investigator measures the outcome and the exposures in the study participants at the same time. Unlike in case-control studies (participants selected based on the outcome status) or cohort studies (participants selected based on the exposure status), the participants in a cross-sectional study are just selected based on the inclusion and exclusion criteria set for the study. Once the participants have been selected for the study, the investigator follows the study to assess the exposure and the outcomes. Cross-sectional designs are used for population-based surveys and to assess the prevalence of diseases in clinic-based samples. These studies can usually be conducted relatively faster and are inexpensive. They may be conducted either before planning a cohort study or a baseline in a cohort study. These types of designs will give us information about the prevalence of outcomes or exposures; this information will be useful for designing the cohort study. However, since this is a 1-time measurement of exposure and outcome, it is difficult to derive causal relationships from cross-sectional analysis. We can estimate the prevalence of disease in cross-sectional studies. Furthermore, we will also be able to estimate the odds ratios to study the association between exposure and the outcomes in this design.
Compilation of cross-sections. Pt. 1
International Nuclear Information System (INIS)
Flaminio, V.; Moorhead, W.G.; Morrison, D.R.O.; Rivoire, N.
1983-01-01
A compilation of integral cross-sections for hadronic reactions is presented. This is an updated version of CERN/HERA 79-1, 79-2, 79-3. It contains all data published up to the beginning of 1982, but some more recent data have also been included. Plots of the cross-sections versus incident laboratory momentum are also given. (orig.)
Compilation of cross-sections. Pt. 4
International Nuclear Information System (INIS)
Alekhin, S.I.; Ezhela, V.V.; Lugovsky, S.B.; Tolstenkov, A.N.; Yushchenko, O.P.; Baldini, A.; Cobal, M.; Flaminio, V.; Capiluppi, P.; Giacomelli, G.; Mandrioli, G.; Rossi, A.M.; Serra, P.; Moorhead, W.G.; Morrison, D.R.O.; Rivoire, N.
1987-01-01
This is the fourth volume in our series of data compilations on integrated cross-sections for weak, electromagnetic, and strong interaction processes. This volume covers data on reactions induced by photons, neutrinos, hyperons, and K L 0 . It contains all data published up to June 1986. Plots of the cross-sections versus incident laboratory momentum are also given. (orig.)
Some bounds on pion-scattering amplitudes and their applications
International Nuclear Information System (INIS)
Chung, B.K.; Vinh Mau, R.
1976-01-01
If one uses the method introduced by Meinam and further developed by Martin, together with unitarity crossing symmetry and analyticity, upper and lower bounds to the πdeg πged scattering amplitudes inside the Mandelstam triangle are obtained in terms of the scattering lengths. These bounds are used to set a lower bound to the renormalized pion coupling constant lambda. In terms of the D-wave scattering length a 2 , the results are a 0 greater than or equal to -23.18 square root a 2 + 129.07a 2 and -7.71 square root a 2 less than or equal to lambda less than or equal to 7.71 square root a 2 +2.5a 2 . For a 2 =7.10 -4 they yield a 2 greater than or equal to -0.52 and lambda less than or equal to 0.20 where the pion, mass is set equal to unity
Evaluation of fusion-evaporation cross-section calculations
Blank, B.; Canchel, G.; Seis, F.; Delahaye, P.
2018-02-01
Calculated fusion-evaporation cross sections from five different codes are compared to experimental data. The present comparison extents over a large range of nuclei and isotopic chains to investigate the evolution of experimental and calculated cross sections. All models more or less overestimate the experimental cross sections. We found reasonable agreement by using the geometrical average of the five model calculations and dividing the average by a factor of 11.2. More refined analyses are made for example for the 100Sn region.
Virtual-pion and two-photon production in pp scattering
International Nuclear Information System (INIS)
Scholten, O.; Korchin, A.Yu.
2002-01-01
Two-photon production in pp scattering is proposed as a means of studying virtual-pion emission. Such a process is complementary to real-pion emission in pp scattering. The virtual-pion signal is embedded in a background of double-photon bremsstrahlung. We have developed a model to describe this background process and show that in certain parts of phase space the virtual-pion signal gives significant contributions. In addition, through interference with the two-photon bremsstrahlung background, one can determine the relative phase of the virtual-pion process
NDS multigroup cross section libraries
International Nuclear Information System (INIS)
DayDay, N.
1981-12-01
A summary description and documentation of the multigroup cross section libraries which exist at the IAEA Nuclear Data Section are given in this report. The libraries listed are available either on tape or in printed form. (author)
Neutron-induced fission cross sections
International Nuclear Information System (INIS)
Weigmann, H.
1991-01-01
In the history of fission research, neutron-induced fission has always played the most important role. The practical importance of neutron-induced fission rests upon the fact that additional neutrons are produced in the fission process, and thus a chain reaction becomes possible. The practical applications of neutron-induced fission will not be discussed in this chapter, but only the physical properties of one of its characteristics, namely (n,f) cross sections. The most important early summaries on the subject are the monograph edited by Michaudon which also deals with the practical applications, the earlier review article on fission by Michaudon, and the review by Bjornholm and Lynn, in which neutron-induced fission receives major attention. This chapter will attempt to go an intermediate way between the very detailed theoretical treatment in the latter review and the cited monograph which emphasizes the applied aspects and the techniques of fission cross-section measurements. The more recent investigations in the field will be included. Section II will survey the properties of cross sections for neutron-induced fission and also address some special aspects of the experimental methods applied in their measurement. Section Ill will deal with the formal theory of neutron-induced nuclear reactions for the resolved resonance region and the region of statistical nuclear reactions. In Section IV, the fission width, or fission transmission coefficient, will be discussed in detail. Section V will deal with the broader structures due to incompletely damped vibrational resonances, and in particular will address the special case of thorium and neighboring isotopes. Finally, Section VI will briefly discuss parity violation effects in neutron-induced fission. 74 refs., 14 figs., 3 tabs
Soft and hard contributions to hard pion photoproduction
International Nuclear Information System (INIS)
Afanasev, Andrei; Carlson, Carl E.; Wahlquist, Christian
2000-01-01
Pion photoproduction at high transverse momentum supplements what can be learned in the standard probes of deep inelastic scattering and Drell-Yan processes. With polarized initial states there is sensitivity to the polarized gluon distribution, Δg, in leading order. This contrasts to other processes mentioned, which have no leading order gluon contribution. Additionally, in some kinematic regions the process occurs mainly due to pion production at short distances ('direct pion production', resulting in kinematically isolated pions), which gives sensitivity to the high-x valence quark distribution
International Nuclear Information System (INIS)
Andrieu, B.; Ban, J.; Barrelet, E.; Bergstein, H.; Bernardi, G.; Besancon, M.; Binder, E.; Blume, H.; Borras, K.; Boudry, V.; Brasse, F.; Braunschweig, W.; Brisson, V.; Campbell, A.J.; Carli, T.; Colombo, M.; Coutures, C.; Cozzika, G.; David, M.; Delcourt, B.; DelBuono, L.; Devel, M.; Dingus, P.; Drescher, A.; Duboc, J.; Duenger, O.; Ebbinghaus, R.; Egli, S.; Ellis, N.N.; Feltesse, J.; Feng, Y.; Ferrarotto, F.; Flauger, W.; Flieser, M.; Gamerdinger, K.; Gayler, J.; Godfrey, L.; Goerlich, L.; Goldberg, M.; Graessler, R.; Greenshaw, T.; Greif, H.; Haguenauer, M.; Hajduk, L.; Hamon, O.; Hartz, P.; Haustein, V.; Haydar, R.; Hildesheim, W.; Huot, N.; Jabiol, M.A.; Jacholkowska, A.; Jaffre, M.; Jung, H.; Just, F.; Kiesling, C.; Kirchhoff, T.; Kole, F.; Korbel, V.; Korn, M.; Krasny, W.; Kubenka, J.P.; Kuester, H.; Kurzhoefer, J.; Kuznik, B.; Lander, R.; Laporte, J.F.; Lenhardt, U.; Loch, P.; Lueers, D.; Marks, J.; Martyniak, J.; Merz, T.; Naroska, B.; Nau, A.; Nguyen, H.K.; Niebergall, F.; Oberlack, H.; Obrock, U.; Ould-Saada, F.; Pascaud, C.; Pyo, H.B.; Rauschnabel, K.; Ribarics, P.; Rietz, M.; Royon, C.; Rusinov, V.; Sahlmann, N.; Sanchez, E.; Schacht, P.; Schleper, P.; Schlippe, W. von; Schmidt, C.; Schmidt, D.; Shekelyan, V.; Shooshtari, H.; Sirois, Y.; Staroba, P.; Steenbock, M.; Steiner, H.; Stella, B.; Straumann, U.; Turnau, J.; Tutas, J.; Urban, L.; Vallee, C.; Vecko, M.; Verrecchia, P.; Villet, G.; Vogel, E.; Wagener, A.; Wegener, D.; Wegner, A.; Wellisch, H.P.; Yiou, T.P.; Zacek, J.; Zeitnitz, Ch.; Zomer, F.
1993-01-01
We present results on calibration runs performed with pions at CERN SPS for different modules of the H1 liquid argon calorimeter which consists of an electromagnetic section with lead absorbers and a hadronic section with steel absorbers. The data cover an energy range from 3.7 to 205 GeV. Detailed comparisons of the data and simulation with GHEISHA 8 in the framework of GEANT 3.14 are presented. The measured pion induced shower profiles are well described by the simulation. The total signal of pions on an energy scale determined from electron measurements is reproduced to better than 3% in various module configurations. After application of weighting functions, determined from Monte Carlo data and needed to achieve compensation, the reconstructed measured energies agree with simulation to about 3%. The energies of hadronic showers are reconstructed with a resolution of about 50%/√E + 2%. This result is achieved by inclusion of signals from an iron streamer tube tail catcher behind the liquid argon stacks. (orig.)
Factorization and pion form factor in QCD
International Nuclear Information System (INIS)
Efremov, A.V.; Radyushkin, A.V.
1979-01-01
The behaviour of the pion electromagnetic form factor (EMFF) in the framework of quantum chromodynamics (QCD) is discussed. Pion is considered to be a quark-antiquark bound state. It is proposed to use an OPE description of the bound state structure by matrix elements of certain local gauge-invariant operators. Short-distance quark interactions is proved using a direct analysis of perturbation theory in the α-parametric representation of the Feynman diagrams. It is shown that the short-distance parton picture privides a self-consistent description of the large Q 2 momentum behaviour of the pion EMFF in QCD. Pion EMFF asymptotics is expressed in terms of fu fundamental constants of the theory
ENDF/B-5 fission product cross section evaluations
International Nuclear Information System (INIS)
Schenter, R.E.; England, T.R.
1979-12-01
Cross section evaluations were made for the 196 fission product nuclides on the ENDF/B-5 data files. Most of the evaluations involve updating the capture cross sections of the important absorbers for fast and thermal reactor systems. This included updating thermal values, resonance integrals, resonance parameter sets, and fast capture cross sections. For the fast capture results generalized least-squares calculations were made with the computer code FERRET. Input for these cross section adjustments included nuclear models calculations and both integral and differential experimental data results. The differential cross sections and their uncertainties were obtained from the CSIRS library. Integral measurement results came from CFRMF and STEK Assemblies 500, 1000, 2000, 3000, 4000. Comparisons of these evaluations with recent capture measurements are shown. 15 figures, 10 tables
Nuclear fission and neutron-induced fission cross-sections
Energy Technology Data Exchange (ETDEWEB)
James, G.D.; Lynn, J.E.; Michaudon, A.; Rowlands, J.; de Saussure, G.
1981-01-01
A general presentation of current knowledge of the fission process is given with emphasis on the low energy fission of actinide nuclei and neutron induced fission. The need for and the required accuracy of fission cross section data in nuclear energy programs are discussed. A summary is given of the steps involved in fission cross section measurement and the range of available techniques. Methods of fission detection are described with emphasis on energy dependent changed and detector efficiency. Examples of cross section measurements are given and data reduction is discussed. The calculation of fission cross sections is discussed and relevant nuclear theory including the formation and decay of compound nuclei and energy level density is introduced. A description of a practical computation of fission cross sections is given.
Effects of the pion string at heavy ion collisions
International Nuclear Information System (INIS)
Mao Hong; Li Yunde; East China Normal Univ., Shanghai
2005-01-01
The authors study the possible signals of the pion string associated with the QCD chiral phase transition in LHC Pb-Pb collision at energy √s=5.5 TeV. The authors follow the Kibble-Zurek mechanism to discuss the production and evolution of the pion string. The authors will show that if the QCD chiral phase transition really takes place in the LHC Pb-Pb collision process and the phase transition is in the second order, the pion string will be inevitably produced and subsequently decay. The main effect of this phenomenon is that there is a generation of a large number of pions in the final state produced by the decay of the pion string, and these pions are mostly distributed in a low momentum region with p-143 MeV; also there are lots of neutral pions distributed in a low momentum region with the mean momentum at p-21 MeV. (authors)
Effects of the pion string at heavy ion collisions
Mao, Hong
2005-01-01
We study the possible signals of the pion string associated with the QCD chiral phase transition in LHC Pb-Pb collision at energy square root s=5.5 TeV. We follow the Kibble-Zurek mechanism to discuss the production and evolution of the pion string. We will show that if the QCD chiral phase transition really takes place in the LHC Pb-Pb collision process and the phase transition is in the second order, the pion string will be inevitably produced and subsequently decay. The main effect of this phenomenon is that there is a generation of a large number of pions in the final state produced by the decay of the pion string, and these pions are mostly distributed in a low momentum region with p143 MeV; also there are lots of neutral pions distributed in a low momentum region with the mean momentum at p21 Me V.
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
Model cross section calculations using LAHET
International Nuclear Information System (INIS)
Prael, R.E.
1992-01-01
The current status of LAHET is discussed. The effect of a multistage preequilibrium exciton model following the INC is examined for neutron emission benchmark calculations, as is the use of a Fermi breakup model for light nuclei rather than an evaporation model. Comparisons are made also for recent fission cross section experiments, and a discussion of helium production cross sections is presented
Interference analysis of fission cross section
International Nuclear Information System (INIS)
Toshkov, S.A.; Yaneva, N.B.
1976-01-01
The formula for the reaction cross-section based on the R-matrix formalism considering the interference between the two neighbouring resonances, referred to the same value of total momentum was used for the analysis of the cross-section of resonance neutron induced fission of 230Pu. The experimental resolution and thermal motion of the target nuclei were accounted for numerical integration
Total cross sections for electron scattering by He
International Nuclear Information System (INIS)
De Heer, F.J.; Jansen, R.H.J.
1977-01-01
A set of total cross sections for scattering of electrons by He has been evaluated over the energy range of zero to 3000 eV by means of the analysis of experiments and theories on total cross sections for elastic scattering, ionisation and excitation, and on differential cross sections for elastic and inelastic scattering. Between 0 and 19.8 eV, where no inelastic processes occur, the total cross sections for scattering are equal to those for elastic scattering. Above 19.8 eV total cross sections for scattering of electrons have been evaluated by adding those for ionisation, excitation and elastic scattering. The total cross sections thus obtained are probably accurate to about 5% over a large part of the energy range. They appear to be in very good agreement with the recent experimental results of Blaauw et al. (J. Phys. B.; 10:L299 (1977)). The present results have already proved useful for application in the dispersion relation for forward scattering in electron-helium collisions. (author)
Cross Sections for Inner-Shell Ionization by Electron Impact
Energy Technology Data Exchange (ETDEWEB)
Llovet, Xavier, E-mail: xavier@ccit.ub.edu [Centres Científics i Tecnològics, Universitat de Barcelona, Lluís Solé i Sabarís 1-3, 08028 Barcelona (Spain); Powell, Cedric J. [Materials Measurement Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8370 (United States); Salvat, Francesc [Facultat de Física (ECM and ICC), Universitat de Barcelona, Diagonal 645, 08028 Barcelona (Spain); Jablonski, Aleksander [Institute of Physical Chemistry, Polish Academy of Sciences, ul. Kasprzaka 44/52, 01-224 Warsaw (Poland)
2014-03-15
An analysis is presented of measured and calculated cross sections for inner-shell ionization by electron impact. We describe the essentials of classical and semiclassical models and of quantum approximations for computing ionization cross sections. The emphasis is on the recent formulation of the distorted-wave Born approximation by Bote and Salvat [Phys. Rev. A 77, 042701 (2008)] that has been used to generate an extensive database of cross sections for the ionization of the K shell and the L and M subshells of all elements from hydrogen to einsteinium (Z = 1 to Z = 99) by electrons and positrons with kinetic energies up to 1 GeV. We describe a systematic method for evaluating cross sections for emission of x rays and Auger electrons based on atomic transition probabilities from the Evaluated Atomic Data Library of Perkins et al. [Lawrence Livermore National Laboratory, UCRL-ID-50400, 1991]. We made an extensive comparison of measured K-shell, L-subshell, and M-subshell ionization cross sections and of Lα x-ray production cross sections with the corresponding calculated cross sections. We identified elements for which there were at least three (for K shells) or two (for L and M subshells) mutually consistent sets of cross-section measurements and for which the cross sections varied with energy as expected by theory. The overall average root-mean-square deviation between the measured and calculated cross sections was 10.9% and the overall average deviation was −2.5%. This degree of agreement between measured and calculated ionization and x-ray production cross sections was considered to be very satisfactory given the difficulties of these measurements.
In-medium pion valence distributions in a light-front model
Energy Technology Data Exchange (ETDEWEB)
Melo, J.P.B.C. de, E-mail: joao.mello@cruzeirodosul.edu.br [Laboratório de Física Teórica e Computacional – LFTC, Universidade Cruzeiro do Sul, 01506-000 São Paulo (Brazil); Tsushima, K. [Laboratório de Física Teórica e Computacional – LFTC, Universidade Cruzeiro do Sul, 01506-000 São Paulo (Brazil); Ahmed, I. [Laboratório de Física Teórica e Computacional – LFTC, Universidade Cruzeiro do Sul, 01506-000 São Paulo (Brazil); National Center for Physics, Quaidi-i-Azam University Campus, Islamabad 45320 (Pakistan)
2017-03-10
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.
Floodplain Cross Section Lines
Department of Homeland Security — This table is required for any Digital Flood Insurance Rate Map database where cross sections are shown on the Flood Insurance Rate Map (FIRM). Normally any FIRM...
Quasielastic knock out of light fragments from 12C and 16O by intermediate energy pions
International Nuclear Information System (INIS)
Abramov, B.M.; Borodin, Yu.A.; Bulychev, S.A.
2006-01-01
Using 0.72 GeV s -1 pulse π - -meson beam one studied the quasi-elastic knocking out of deuterons and of tritons from 12 C and 16 O nuclei. One derived the quasi-deuteron intranuclear motion pulse distributions, the residual nucleus excitation energy spectra and the effective number of quasi-deuterons. The parameters of quasi-deuteron intranuclear motion pulse distributions are in line with the measurement results for other beams. The effective numbers of quasi-deuterons in nuclei from 6 Li up to 16 O do not depend on the atomic number. One observed knocking out of tritons from the mentioned nuclei enabling to evaluate the cross section of elastic pion-triton backscattering [ru
A Pebble Bed Reactor cross section methodology
International Nuclear Information System (INIS)
Hudson, Nathanael H.; Ougouag, Abderrafi M.; Rahnema, Farzad; Gougar, Hans
2009-01-01
A method is presented for the evaluation of microscopic cross sections for the Pebble Bed Reactor (PBR) neutron diffusion computational models during convergence to an equilibrium (asymptotic) fuel cycle. This method considers the isotopics within a core spectral zone and the leakages from such a zone as they arise during reactor operation. The randomness of the spatial distribution of fuel grains within the fuel pebbles and that of the fuel and moderator pebbles within the core, the double heterogeneity of the fuel, and the indeterminate burnup of the spectral zones all pose a unique challenge for the computation of the local microscopic cross sections. As prior knowledge of the equilibrium composition and leakage is not available, it is necessary to repeatedly re-compute the group constants with updated zone information. A method is presented to account for local spectral zone composition and leakage effects without resorting to frequent spectrum code calls. Fine group data are pre-computed for a range of isotopic states. Microscopic cross sections and zone nuclide number densities are used to construct fine group macroscopic cross sections, which, together with fission spectra, flux modulation factors, and zone buckling, are used in the solution of the slowing down balance to generate a new or updated spectrum. The microscopic cross-sections are then re-collapsed with the new spectrum for the local spectral zone. This technique is named the Spectral History Correction (SHC) method. It is found that this method accurately recalculates local broad group microscopic cross sections. Significant improvement in the core eigenvalue, flux, and power peaking factor is observed when the local cross sections are corrected for the effects of the spectral zone composition and leakage in two-dimensional PBR test problems.
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.)
Transport cross section for small-angle scattering
International Nuclear Information System (INIS)
D'yakonov, M.I.; Khaetskii, A.V.
1991-01-01
Classical mechanics is valid for describing potential scattering under the conditions (1) λ much-lt α and (2) U much-gt ℎυ/α, where λ is the de Broglie wavelength, α is the characteristic size of the scatterer, U is the characteristic value of the potential energy, and υ is the velocity of the scattered particle. The second of these conditions means that the typical value of the classical scattering angle is far larger than the diffraction angle λ/α. In this paper the authors show that this second condition need not hold in a derivation of the transport cross section. In other words, provided that the condition λ much-lt α holds, it is always possible to calculate the transport cross section from the expressions of classical mechanics, even in the region U approx-lt ℎυ/α, where the scattering is diffractive,and the differential cross section is greatly different from the classical cross section. The transport cross section is found from the classical expression even in the anticlassical case U much-lt ℎυ/α, where the Born approximation can be used
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
Nonelastic-scattering cross sections of elemental nickel
International Nuclear Information System (INIS)
Smith, A.B.; Guenther, P.T.; Whalen, J.F.
1980-06-01
Neutron total cross sections of elemental nickel were measured from 1.3 to 4.5 MeV, at intervals of approx. 50 keV, with resolutions of 30 to 50 keV and to accuracies of 1 to 2.5%. Neutron differential-elastic-scattering cross sections were measured from 1.45 to 3.8 MeV, at intervals and with resolutions comparable to those of the total cross sections, and to accuracies of 3 to 5%. The nonelastic-scattering cross section is derived from the measured values to accuracies of greater than or equal to 6%. The experimental results are compared with previously reported values as represented by ENDF/B-V, and areas of consistency and discrepancy, noted. The measured results are shown to be in good agreement with the predictions of a model previously reported by the authors. 4 figures, 1 table
Negative pion irradiation of mammalian cells
International Nuclear Information System (INIS)
Dertinger, H.; Luecke-Huhle, C.; Schlag, H.; Weibezahn, K.F.
1976-01-01
Monolayers and spheroids of Chinese hamster cells (V79) were subjected to negative pion irradiation under aerobic conditions. R.b.e. values in the pion peak of 1.8 and 1.5 were obtained for monolayers and spheroids, respectively, whereas the r.b.e. for the plateau was found to be slightly higher than 1. In addition, it was observed that the higher resistance of the V79 spheroid cells than the monolayers to γ-irradiation is not diminished in the pion peak, suggesting that the underlying phenomenon of intercellular communication influences cell survival even after high-LET irradiation. (author)
Fragmentation cross sections outside the limiting-fragmentation regime
Sümmerer, K
2003-01-01
The empirical parametrization of fragmentation cross sections, EPAX, has been successfully applied to estimate fragment production cross sections in reactions of heavy ions at high incident energies. It is checked whether a similar parametrization can be found for proton-induced spallation around 1 GeV, the range of interest for ISOL-type RIB facilities. The validity of EPAX for medium-energy heavy-ion induced reactions is also checked. Only a few datasets are available, but in general EPAX predicts the cross sections rather well, except for fragments close to the projectile, where the experimental cross sections are found to be larger.
Covariant density functional theory: The role of the pion
International Nuclear Information System (INIS)
Lalazissis, G. A.; Karatzikos, S.; Serra, M.; Otsuka, T.; Ring, P.
2009-01-01
We investigate the role of the pion in covariant density functional theory. Starting from conventional relativistic mean field (RMF) theory with a nonlinear coupling of the σ meson and without exchange terms we add pions with a pseudovector coupling to the nucleons in relativistic Hartree-Fock approximation. In order to take into account the change of the pion field in the nuclear medium the effective coupling constant of the pion is treated as a free parameter. It is found that the inclusion of the pion to this sort of density functionals does not destroy the overall description of the bulk properties by RMF. On the other hand, the noncentral contribution of the pion (tensor coupling) does have effects on single particle energies and on binding energies of certain nuclei.
Measurements of fission cross-sections. Chapter 4
International Nuclear Information System (INIS)
James, G.D.
1981-01-01
The steps involved in the measurement of fission cross sections are summarized and the range of techniques available are considered. Methods of fission detection are described with particular emphasis on the neutron energy dependent properties of the fission process and the details of fragment energy loss which can lead to energy-dependent changes in detector efficiency. Selected examples of fission cross-section measurements are presented and methods of data reduction, storage, analysis and evaluation, are examined. Finally requested accuracies for fission cross section data are compared to estimated available accuracies. (U.K.)
Vibrational enhancement of total breakup cross sections
International Nuclear Information System (INIS)
Haftel, M.I.; Lim, T.K.
1984-01-01
This paper considers the role of multi-two-body bound states, namely vibrational excitations, on total three-body breakup cross-sections. Total cross-sections are usually easy to measure, and they play a fundamental role in chemical kinetics. (orig.)
Target dependence of K+-nucleus total cross sections
International Nuclear Information System (INIS)
Jiang, M.F.; Ernst, D.J.; Chen, C.M.
1995-01-01
We investigate the total cross section and its target dependence for K + -nucleus scattering using a relativistic momentum-space optical potential model which incorporates relativistically normalized wave functions, invariant two-body amplitudes, covariant kinematics, and an exact full-Fermi averaging integral. The definition of the total cross section in the presence of a Coulomb interaction is reviewed and the total cross section is calculated in a way that is consistent with what is extracted from experiment. In addition, the total cross sections for a nucleus and for the deuteron are calculated utilizing the same theory. This minimizes the dependence of the ratio of these cross sections on the details of the theory. The model dependence of the first-order optical potential calculations is investigated. The theoretical results are found to be systematically below all existing data
Tables of RCN-2 fission-product cross section evaluation
International Nuclear Information System (INIS)
Gruppelaar, H.
1979-05-01
This report (continuation of ECN-13 and ECN-33) describes the third part of the RCN-2 evaluation of neutron cross sections for fission product nuclides in KEDAK format. It contains evaluated data for nine nuclides, i.e. 142 Nd, 143 Nd, 144 Nd, 145 Nd, 146 Nd, 147 Nd, 148 Nd, 150 Nd and 147 Pm. Most emphasis has been given to the evaluation of the radiative capture cross section, in order to provide a data base for adjustment calculations using results of integral measurements. Short evaluation reports are given for this cross section. The evaluated capture cross sections are compared with recent experimental differential and integral data. Graphs are given of the capture cross sections at neutron energies above 1 keV, in which also adjusted point cross sections, based upon integral STEK and CFRMF data have been plotted. Moreover, the results are compared with those of the well-known ENDF/B-IV evaluation for fission product nucleides. Finally, evaluation summaries are given, which include tables of other important neutron cross sections, such as the total, elastic scattering and inelastic scattering cross sections
Microscopic cross sections: An utopia?
Energy Technology Data Exchange (ETDEWEB)
Hilaire, S. [CEA Bruyeres-le-Chatel, DIF 91 (France); Koning, A.J. [Nuclear Research and Consultancy Group, PO Box 25, 1755 ZG Petten (Netherlands); Goriely, S. [Institut d' Astronomie et d' Astrophysique, Universite Libre de Bruxelles, Campus de la Plaine, CP 226, 1050 Brussels (Belgium)
2010-07-01
The increasing need for cross sections far from the valley of stability poses a challenge for nuclear reaction models. So far, predictions of cross sections have relied on more or less phenomenological approaches, depending on parameters adjusted to available experimental data or deduced from systematical relations. While such predictions are expected to be reliable for nuclei not too far from the experimentally known regions, it is clearly preferable to use more fundamental approaches, based on sound physical bases, when dealing with very exotic nuclei. Thanks to the high computer power available today, all major ingredients required to model a nuclear reaction can now be (and have been) microscopically (or semi-microscopically) determined starting from the information provided by a nucleon-nucleon effective interaction. We have implemented all these microscopic ingredients in the TALYS nuclear reaction code, and we are now almost able to perform fully microscopic cross section calculations. The quality of these ingredients and the impact of using them instead of the usually adopted phenomenological parameters will be discussed. (authors)
Microscopic cross sections: An utopia?
International Nuclear Information System (INIS)
Hilaire, S.; Koning, A.J.; Goriely, S.
2010-01-01
The increasing need for cross sections far from the valley of stability poses a challenge for nuclear reaction models. So far, predictions of cross sections have relied on more or less phenomenological approaches, depending on parameters adjusted to available experimental data or deduced from systematical relations.While such predictions are expected to be reliable for nuclei not too far from the experimentally known regions, it is clearly preferable to use more fundamental approaches, based on sound physical bases, when dealing with very exotic nuclei. Thanks to the high computer power available today, all major ingredients required to model a nuclear reaction can now be (and have been) microscopically (or semi-microscopically) determined starting from the information provided by a nucleon-nucleon effective interaction. We have implemented all these microscopic ingredients in the TALYS nuclear reaction code, and we are now almost able to perform fully microscopic cross section calculations. The quality of these ingredients and the impact of using them instead of the usually adopted phenomenological parameters will be discussed. (authors)
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
Adams, J; Adler, C; Aggarwal, M M; Ahammed, Z; Amonett, J; Anderson, B D; Anderson, M; Arkhipkin, D; Averichev, G S; Badyal, S K; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellwied, R; Berger, J; Bezverkhny, B I; Bhardwaj, S; Bhaskar, P; Bhati, A K; Bichsel, H; Billmeier, A; Bland, L C; Blyth, C O; Bonner, B E; Botje, M; Boucham, A; Brandin, A; Bravar, A; Cadman, R V; Cai, X Z; Caines, H; Calderón de la Barca Sánchez, M; Carroll, J; Castillo, J; Castro, M; Cebra, D; Chaloupka, P; Chattopadhyay, S; Chen, H F; Chen, Y; Chernenko, S P; Cherney, M; Chikanian, A; Choi, B; Christie, W; Coffin, J P; Cormier, T M; Cramer, J G; Crawford, H J; Das, D; Das, S; Derevschikov, A A; Didenko, L; Dietel, T; Dong, W J; Dong, X; Draper, J E; Du, F; Dubey, A K; Dunin, V B; Dunlop, J C; Dutta Majumdar, M R; Eckardt, V; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Estienne, M; Fachini, P; Faine, V; Faivre, J; Fatemi, R; Filimonov, K; Filip, P; Finch, E; Fisyak, Y; Flierl, D; Foley, K J; Fu, J; Gagliardi, C A; Gagunashvili, N; Gans, J; Ganti, M S; Gaudichet, L; Germain, M; Geurts, F; Ghazikhanian, V; Ghosh, P; Gonzalez, J E; Grachov, O; Grigoriev, V; Gronstal, S; Grosnick, D; Guedon, M; Guertin, S M; Gupta, A; Gushin, E; Gutierrez, T D; Hallman, T J; Hardtke, D; Harris, J W; Heinz, M; Henry, T W; Heppelmann, S; Herston, T; Hippolyte, B; Hirsch, A; Hjort, E; Hoffmann, G W; Horsley, M; Huang, H Z; Huang, S L; Humanic, T J; Igo, G; Ishihara, A; Jacobs, P; Jacobs, W W; Janik, M; Jiang, H; Johnson, I; Jones, P G; Judd, E G; Kabana, S; Kaneta, M; Kaplan, M; Keane, D; Khodyrev, V Yu; Kiryluk, J; Kisiel, A; Klay, J; Klein, S R; Klyachko, A; Koetke, D D; Kollegger, T; Kopytine, M; Kotchenda, L; Kovalenko, A D; Kramer, M; Kravtsov, P; Kravtsov, V I; Krueger, K; Kuhn, C; Kulikov, A I; Kumar, A; Kunde, G J; Kunz, C L; Kutuev, R Kh; Kuznetsov, A A; Lamont, M A C; Landgraf, J M; Lange, S; Lansdell, C P; Lasiuk, B; Laue, F; Lauret, J; Lebedev, A; Lednický, R; LeVine, M J; Li, C; Li, Q; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, L; Liu, Z; Liu, Q J; Ljubicic, T; Llope, W J; Long, H; Longacre, R S; Lopez-Noriega, M; Love, W A; Ludlam, T; Lynn, D; Ma, J; Ma, Y G; Magestro, D; Mahajan, S; Mangotra, L K; Mahapatra, D P; Majka, R; Manweiler, R; Margetis, S; Markert, C; Martin, L; Marx, J; Matis, H S; Matulenko, Yu A; McShane, T S; Meissner, F; Melnick, Yu; Meschanin, A; Messer, M; Miller, M L; Milosevich, Z; Minaev, N G; Mironov, C; Mishra, D; Mitchell, J; Mohanty, B; Molnar, L; Moore, C F; Mora-Corral, M J; Morozov, D A; Morozov, V; de Moura, M M; Munhoz, M G; Nandi, B K; Nayak, S K; Nayak, T K; Nelson, J M; Nevski, P; Nikitin, V A; Nogach, L V; Norman, B; Nurushev, S B; Odyniec, G; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Paic, G; Pandey, S U; Pal, S K; Panebratsev, Y; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Perevoztchikov, V; Perkins, C; Peryt, W; Petrov, V A; Phatak, S C; Picha, R; Planinic, M; Pluta, J; Porile, N; Porter, J; Poskanzer, A M; Potekhin, M; Potrebenikova, E; Potukuchi, B V K S; Prindle, D; Pruneau, C; Putschke, J; Rai, G; Rakness, G; Raniwala, R; Raniwala, S; Ravel, O; Ray, R L; Razin, S V; Reichhold, D; Reid, J G; Renault, G; Retiere, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevski, O V; Romero, J L; Rose, A; Roy, C; Ruan, L J; Sahoo, R; Sakrejda, I; Salur, S; Sandweiss, J; Savin, I; Schambach, J; Scharenberg, R P; Schmitz, N; Schroeder, L S; Schweda, K; Seger, J; Seliverstov, D; Seyboth, P; Shahaliev, E; Shao, M; Sharma, M; Shestermanov, K E; Shimanskii, S S; Singaraju, R N; Simon, F; Skoro, G; Smirnov, N; Snellings, R; Sood, G; Sorensen, P; Sowinski, J; Spinka, H M; Srivastava, B; Stanislaus, S; Stock, R; Stolpovsky, A; Strikhanov, M; Stringfellow, B; Struck, C; Suaide, A A P; Sugarbaker, E; Suire, C; Sumbera, M; Surrow, B; Symons, T J M; Szanto de Toledo, A; Szarwas, P; Tai, A; Takahashi, J; Tang, A H; Thein, D; Thomas, J H; Tikhomirov, V; Tokarev, M; Tonjes, M B; Trainor, T A; Trentalange, S; Tribble, R E; Trivedi, M D; Trofimov, V; Tsai, O; Ullrich, T; Underwood, D G; Van Buren, G; VanderMolen, A M; Vasiliev, A N; Vasiliev, M; Vigdor, S E; Viyogi, Y P; Voloshin, S A; Waggoner, W; Wang, F; Wang, G; Wang, X L; Wang, Z M; Ward, H; Watson, J W; Wells, R; Westfall, G D; Whitten, C; Wieman, H; Willson, R; Wissink, S W; Witt, R; Wood, J; Wu, J; Xu, N; Xu, Z; Xu, Z Z; Yamamoto, E; Yepes, P; Yurevich, V I; Zanevski, Y V; Zborovský, I; Zhang, H; Zhang, W M; Zhang, Z P; Zołnierczuk, P A; Zoulkarneev, R; Zoulkarneeva, J; Zubarev, A N
2004-04-30
Measurements of the production of forward high-energy pi(0) mesons from transversely polarized proton collisions at sqrt[s]=200 GeV are reported. The cross section is generally consistent with next-to-leading order perturbative QCD calculations. The analyzing power is small at x(F) below about 0.3, and becomes positive and large at higher x(F), similar to the trend in data at sqrt[s]1 GeV/c at a polarized proton collider.
Multilevel parametrization of fissile nuclei resonance cross sections
International Nuclear Information System (INIS)
Lukyanov, A.A.; Kolesov, V.V.; Janeva, N.
1987-01-01
Because the resonance interference has an important influence on the resonance structure of neutron cross sections energy dependence at lowest energies, multilevel scheme of the cross section parametrization which take into account the resonance interference is used for the description with the same provisions in the regions of the interferential maximum and minimum of the resonance cross sections of the fissile nuclei
Total and ionization cross sections of electron scattering by fluorocarbons
International Nuclear Information System (INIS)
Antony, B K; Joshipura, K N; Mason, N J
2005-01-01
Electron impact total cross sections (50-2000 eV) and total ionization cross sections (threshold to 2000 eV) are calculated for typical plasma etching molecules CF 4 , C 2 F 4 , C 2 F 6 , C 3 F 8 and CF 3 I and the CF x (x 1-3) radicals. The total elastic and inelastic cross sections are determined in the spherical complex potential formalism. The sum of the two gives the total cross section and the total inelastic cross section is used to calculate the total ionization cross sections. The present total and ionization cross sections are found to be consistent with other theories and experimental measurements, where they exist. Our total cross section results for CF x (x = 1-3) radicals presented here are first estimates on these species
Calculation of atom displacement cross section for structure material
International Nuclear Information System (INIS)
Liu Ping; Xu Yiping
2015-01-01
The neutron radiation damage in material is an important consideration of the reactor design. The radiation damage of materials mainly comes from atom displacements of crystal structure materials. The reaction cross sections of charged particles, cross sections of displacements per atom (DPA) and KERMA are the basis of radiation damage calculation. In order to study the differences of DPA cross sections with different codes and different evaluated nuclear data libraries, the DPA cross sections for structure materials were calculated with UNF and NJOY codes, and the comparisons of results were given. The DPA cross sections from different evaluated nuclear data libraries were compared. And the comparison of DPA cross sections between NJOY and Monte Carlo codes was also done. The results show that the differences among these evaluated nuclear data libraries exist. (authors)
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.)
Fast pion production in exclusive neutrino processes
International Nuclear Information System (INIS)
Gershtein, S.S.; Komachenko, Yu.Ya.; Khlopov, M.Yu.
1980-01-01
Single pion production in exclusive neutrino reactions with small momentum transfer to nucleon, induced by neutrino scattering on virtual mesons (reggeons), is considered. The estimation of the contributions to process νA → μπA where A is a nucleon or the target nucleus made by various virtual mesons is presented. In the experimental investigation of such processes the contributions of different mesons may be singled out, thus providing information on the weak; meson-pion (reggeon-pion) transitions
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.)
Preparation of next generation set of group cross sections. 3
International Nuclear Information System (INIS)
Kaneko, Kunio
2002-03-01
This fiscal year, based on the examination result about the evaluation energy range of heavy element unresolved resonance cross sections, the upper energy limit of the energy range, where ultra-fine group cross sections are produced, was raised to 50 keV, and an improvement of the group cross section processing system was promoted. At the same time, reflecting the result of studies carried out till now, a function producing delayed neutron data was added to the general-purpose group cross section processing system , thus the preparation of general purpose group cross section processing system has been completed. On the other hand, the energy structure, data constitution and data contents of next generation group cross section set were determined, and the specification of a 151 groups next generation group cross section set was defined. Based on the above specification, a concrete library format of the next generation cross section set has been determined. After having carried out the above-described work, using the general-purpose group cross section processing system , which was complete in this study, with use of the JENDL-3. 2 evaluated nuclear data, the 151 groups next generation group cross section of 92 nuclides and the ultra fine group resonance cross section library for 29 nuclides have been prepared. Utilizing the 151 groups next generation group cross section set and the ultra-fine group resonance cross-section library, a bench mark test calculation of fast reactors has been performed by using an advanced lattice calculation code. It was confirmed, by comparing the calculation result with a calculation result of continuous energy Monte Carlo code, that the 151 groups next generation cross section set has sufficient accuracy. (author)
Positive Scattering Cross Sections using Constrained Least Squares
International Nuclear Information System (INIS)
Dahl, J.A.; Ganapol, B.D.; Morel, J.E.
1999-01-01
A method which creates a positive Legendre expansion from truncated Legendre cross section libraries is presented. The cross section moments of order two and greater are modified by a constrained least squares algorithm, subject to the constraints that the zeroth and first moments remain constant, and that the standard discrete ordinate scattering matrix is positive. A method using the maximum entropy representation of the cross section which reduces the error of these modified moments is also presented. These methods are implemented in PARTISN, and numerical results from a transport calculation using highly anisotropic scattering cross sections with the exponential discontinuous spatial scheme is presented
Heisenberg rise of total cross sections
International Nuclear Information System (INIS)
Ezhela, V.V.; Yushchenko, O.P.
1988-01-01
It is shown that on the basis of the original idea of Heisenberg on the quasiclassical picture of extended particle interactions one can construct a satisfactory description of the total cross sections, elastic cross sections, elastic diffractive slopes and mean charged multiplicities in the cm energy range from 5 to 900 GeV, and produce reasonable extrapolations up to several tens of TeV. 14 refs.; 7 figs.; 2 tabs
International Nuclear Information System (INIS)
Pashchenko, A.B.; Wienke, H.
1998-01-01
This document presents the description of a physical tape containing the basic evaluated nuclear data library of neutron-nucleus interaction cross sections, photon production cross sections and photon-atom interaction cross sections for fusion applications. It is part of the evaluated nuclear data library for fusion applications FENDL-2. The data are available cost-free from the Nuclear Data Section upon request. The data can also be retrieved by the user via online access through international computer networks. (author)
International Nuclear Information System (INIS)
Coon, S.A.; Scadron, M.D.
1981-01-01
We suggest that the observed 6% Goldberger-Treiman discrepancy is due in part to a 3% variation in the pion-nucleon form factor and in part due to a 3% variation in the pion decay form factor from q 2 =m/sub π/ 2 to q 2 =0