Quark Confinement in C-periodic Cylinders at Temperatures above T_c
Holland, K; Wiese, U.-J.
1997-01-01
Due to the Gauss law, a single quark cannot exist in a periodic volume, while it can exist with C-periodic boundary conditions. In a C-periodic cylinder of cross section A = L_x L_y and length L_z >> L_x, L_y containing deconfined gluons, regions of different high temperature Z(3) phases are aligned along the z-direction, separated by deconfined- deconfined interfaces. In this geometry, the free energy of a single static quark diverges in proportion to L_z. Hence, paradoxically, the quark is ...
Bouzas, Antonio O.; Larios, F.
2015-11-01
We study the DIS and photo-production modes of pairs at the proposed LHeC and its potential to probe the electromagnetic and weak dipole moments (MDM and EDM for ttγ) of the top quark. A framework of eight independent gauge invariant dimension six operators involving the top quark and the electroweak gauge bosons is used. Four of those operators modify the charged tbW coupling which can be probed through the single (anti) top production mode as reported in the literature. One generates ttγ(Z) as well as tbW couplings, while other two do not generate tbW but only ttγ(Z). Our focus is on the MDM and EDM of the top quark for which the photo-production mode of can be an excellent probe. At the proposed electron energies of Ee = 60 and 140 GeV the LHeC could set constraints stronger than the indirect limits from b → sγ and the potential limits of the LHC through production[1].
Bound States of (Anti-)Scalar-Quarks in $SU(3)_{c}$ Lattice QCD
Iida, H; Takahashi, T T
2007-01-01
Light scalar-quarks \\phi (colored scalar particles or idealized diquarks) and their color-singlet hadronic states are studied with quenched SU(3)_c lattice QCD in terms of mass generation. We investigate ``scalar-quark mesons'' \\phi^\\dagger \\phi and ``scalar-quark baryons'' \\phi\\phi\\phi as the bound states of scalar-quarks \\phi. We also investigate the bound states of scalar-quarks \\phi and quarks \\psi, i.e., \\phi^\\dagger \\psi, \\psi\\psi\\phi and \\phi\\phi\\psi, which we name ``chimera hadrons''. All the new-type hadrons including \\phi are found to have a large mass due to large quantum corrections by gluons, even for zero bare scalar-quark mass m_\\phi=0 at a^{-1}\\sim 1{\\rm GeV}. We conjecture that all colored particles generally acquire a large effective mass due to dressed gluon effects.
Scalar-Quark Systems and Chimera Hadrons in SU(3)_c Lattice QCD
Iida, H; Takahashi, T T
2007-01-01
Light scalar-quarks \\phi (colored scalar particles or idealized diquarks) and their color-singlet hadronic states are studied with quenched SU(3)_c lattice QCD in terms of mass generation in strong interaction without chiral symmetry breaking. We investigate ``scalar-quark mesons'' \\phi^\\dagger \\phi and ``scalar-quark baryons'' \\phi\\phi\\phi which are the bound states of scalar-quarks \\phi. We also investigate the bound states of scalar-quarks \\phi and quarks \\psi, i.e., \\phi^\\dagger \\psi, \\psi\\psi\\phi and \\phi\\phi\\psi, which we name ``chimera hadrons''. All the new-type hadrons including \\phi are found to have a large mass even for zero bare scalar-quark mass m_\\phi=0 at a^{-1}\\simeq 1GeV. We find that the constituent scalar-quark and quark picture is satisfied for all the new-type hadrons. Namely, the mass of the new-type hadron composed of m \\phi's and n \\psi's, M_{{m}\\phi+{n}\\psi}, satisfies M_{{m}\\phi+{n}\\psi}\\simeq {m} M_\\phi +{n} M_\\psi, where M_\\phi and M_\\psi are the constituent scalar-quark and quark...
Quark Confinement in C-periodic Cylinders at Temperatures above $T_c$
Holland, K
1997-01-01
Due to the Gauss law, a single quark cannot exist in a periodic volume, while it can exist with C-periodic boundary conditions. In a C-periodic cylinder of cross section A = L_x L_y and length L_z >> L_x, L_y containing deconfined gluons, regions of different high temperature Z(3) phases are aligned along the z-direction, separated by deconfined- deconfined interfaces. In this geometry, the free energy of a single static quark diverges in proportion to L_z. Hence, paradoxically, the quark is confined, although the temperature T is larger than T_c. At T around T_c, the confined phase coexists with the three deconfined phases. The deconfined-deconfined interfaces can be completely or incompletely wet by the confined phase. The free energy of a quark behaves differently in these two cases. In contrast to claims in the literature, our results imply that deconfined-deconfined interfaces are not Euclidean artifacts, but have observable consequences in a system of hot gluons.
Tagging b and c quark events in e+e- collisions with neural networks
International Nuclear Information System (INIS)
High purity samples of b quark events and, if possible, of c quark events are attempted to produce, and the width of Γ(Z0 → bb-bar) is measured. The different variables and the method to select the most discriminating variables are given. The physical results obtained with these methods are recalled, and new results are presented with variables connected with the impact parameter. Some neural networks used throughout this work and some results on c quark events selection are also presented. (K.A.) 9 refs.; 6 figs
A measurement of the weak axial couplings of the b- and c-quark
Energy Technology Data Exchange (ETDEWEB)
Elsen, E.; Ambrus, K.; Bethke, S.; Dieckmann, A.; Eckerlin, G.; Heintze, J.; Hellenbrand, K.H.; Komamiya, S.; Krogh, J. von; Rieseberg, H.; Schmitt, H. von der; Smolik, L.; Spitzer, J.; Wagner, A.; Zimmer, M. (Heidelberg Univ. (Germany, F.R.). Physikalisches Inst.); Allison, J.; Barlow, R.J.; Chrin, J.; Duerdoth, I.P.; Loebinger, F.K.; Macbeth, A.A.; Murphy, P.G.; Stephens, K. (Manchester Univ. (UK)); Bartel, W.; Felst, R.; Haidt, D.; Kado, H.; Knies, G.; Krehbiel, H.; Magnussen, N.; Meinke, R.; Naroska, B.; Olsson, J.; Ramcke, R.; Schmidt, D.; Steffen, P. (Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany, F.R.)); Bowdery, C.K.; Finch, A.J.; Foster, F.; Hughes, G.; Nye, J.M.; Walker, I.W. (Lancaster Univ. (UK)); Cartwright, S.L.; Clarke, D.; Marshall, R.; Middleton, R.P. (Rutherford Appleton Lab., Chilton (UK)); Greenshaw, T.; Hagemann, J.; Heinzelmann, G.; Kleinwort, C.; Kuhlen, M.; Ould-Saada, F.; Schneekloth, U.; Weber, G. (Hamburg Univ. (Germany, F.R.). 2. Inst. fuer; JADE Collaboration
1990-04-01
The forward backward charge asymmetries of the b and c quarks are measured with the JADE detector at PETRA at {radical}s=35 GeV and 44 GeV using both electrons and muons to tag the heavy quarks. At {radical}s=35 GeV, a simultaneous fit for the two asymmetries yields the result A{sub b}=-9.3{plus minus}5.2% (stat.) and A{sub c}=-9.6{plus minus}4.0% (stat.). A fit for the b-asymmetry alone gives A{sub b}=-11.6{plus minus}4.8% (stat.). The systematic errors are comparable with the statistical uncertainties. Combining the measurements at both energies and alternately constraining the weak coupling of the c and b quark to their Standard Model values (a{sub c}=1, a{sub b}=-1) increases the precision of the measurement of coupling constant of the other quark. Using this procedure a{sub b}=-0.72{plus minus}0.34 and a{sub c}=0.79{plus minus}0.40, where the numbers are corrected for Banti B-mixing and the errors include both statistical and systematic contributions. The mixing parameter for continuum banti b-production is determined to be {chi}=0.24{plus minus}0.12 if both heavy quark coupling constants are constrained to their values in the Standard Model. (orig.).
c, b-quark FB asymmetries by inclusive electrons
International Nuclear Information System (INIS)
We have measured, with electron tagging, the forward-backward asymmetries of charm- and bottom-quark pair productions at = 58.01 GeV, based on 23,783 hadronic events selected from a data sample of 197 pb-1 taken with the TOPAZ detector at TRISTAN. The measured forward-backward asymmetries are AFBc = -0.49 ± 0.20(stat.) ± 0.08(sys.) and AFBb = -0.64 ± 0.35(stat.) ± 0.13(sys.), which are consistent with the standard model predictions. (author)
Jido, Daisuke
2016-01-01
The possibility to have diquark configuration in heavy baryons, such as Lambda_c and Lambda_b, is examined by a nonrelativistic potential model with a heavy quark and a light scalar diquark. Assuming that the Lambda_c and Lambda_b baryons are composed of the heavy quark and the scalar-isoscalar ud diquark, we solve the two-body Schrodinger equation with the Coulomb plus linear potential and obtain the energy spectra for the heavy baryons. Contrary to our expectation, it is found that the potential determined by the quarkonium spectra fails to reproduce the excitation spectra of the Lambda_c and Lambda_b in the quark-diquark picture, while the Lambda_c and Lambda_b spectra is reproduced with a half strength of the confinement string tension than for the quarkonium. The Xi_c excitation energy is also calculated and is found to be smaller than Lambda_c in the quark-diquark model. This is not consistent with the experimental observation. These puzzles should be solved when one takes the quark-diquark picture for ...
Quark (diquark) fragmentation in soft π-p interactions at P=40 GeV/c
International Nuclear Information System (INIS)
The quark and diquark fragmentation into π+--, K0-mesons and Λ-hyperons in soft π-p-interactions at 40 GeV/c is studied. Fragmentation Dsup(πsup(+-)) (Xsub(F)) and invariant Fsup(πsup(+-)) (Xsub(F)) functions are compared with analogous data on ν(anti ν)p - interactions. It is shown that a good agreement exists in the region Xsub(F) > or approximately 0.15 for these different processes. The Xsub(E)-dependence of the quark and diquark fragmentation function for neutral kaons is similar to that in e+e- annihilation. The pickup probability of strange s(anti s) quark (lambda sub(s)) and diquark (lambda sub(qq)) relative to u(anti u) and d(anti d) quarks from the sea has been found to be equal to lambda sub(s)=0.17 and lambda sub(qq)=0.14+-0.03
Properties of Scalar-Quark Systems in SU(3)c Lattice QCD
Iida, Hideaki; Suganuma, Hideo
2008-01-01
We perform the first study for the bound states of colored scalar particles $\\phi$ ("scalar quarks") in terms of mass generation with quenched SU(3)$_c$ lattice QCD. We investigate the bound states of $\\phi$, $\\phi^\\dagger\\phi$ and $\\phi\\phi\\phi$ ("scalar-quark hadrons"), as well as the bound states of $\\phi$ and quarks $\\psi$, i.e., $\\phi^\\dagger\\psi$, $\\psi\\psi\\phi$ and $\\phi\\phi\\psi$ ("chimera hadrons"). All these new-type hadrons including $\\phi$ have a large mass of several GeV due to large quantum corrections by gluons, even for zero bare scalar-quark mass $m_\\phi=0$ at $a^{-1}\\sim 1{\\rm GeV}$. We find a similar $m_\\psi$-dependence between $\\phi^\\dagger\\psi$ and $\\phi\\phi\\psi$, which indicates their similar structure due to the large mass of $\\phi$. From this study, we conjecture that all colored particles generally acquire a large effective mass due to dressed gluons.
Hernández, A. E. Cárcamo; Mart'\\inez, R.; Ochoa, F.
2013-01-01
We take up again the study of the mass spectrum of the quark sector in a model with gauge symmetry $SU(3)_{c}\\otimes SU(3)_{L}\\otimes U(1)_{X}$ (331). In a special type II-like 331 model, we obtain specific zero-texture mass matrices for the quarks which predict four massless quarks ($u,c,d,s$) and two massive quarks ($b,t$) at the electroweak scale ($\\sim $ GeV). By considering the mixing between the SM quarks and new exotic quarks at large scales predicted by the model, we find that a third...
Hernández, A E Cárcamo; Ochoa, F
2013-01-01
We take up again the study of the mass spectrum of the quark sector in a model with gauge symmetry $SU(3)_{c}\\otimes SU(3)_{L}\\otimes U(1)_{X}$ (331). In a special type II-like 331 model, we obtain specific zero-texture mass matrices for the quarks which predict four massless quarks ($u,c,d,s$) and two massive quarks ($b,t$) at the electroweak scale ($\\sim $ GeV). By considering the mixing between the SM quarks and new exotic quarks at large scales predicted by the model, we find that a third quark (associated to the charm quark) acquires a mass. The remaining light quarks ($u,d,s$) get small masses ($\\sim$ MeV) via radiative corrections.
Rodionov, E. N.
1994-01-01
We build a model which is based on the assumption that the {\\bf c} and {\\bf s,b} quarks are excited states of {\\bf u} and {\\bf d} quarks. This model predicts the non-existence of the {\\bf top} quark and estimates the size of the quarks to be of order $10^{-7}$ fm.
Abreu, P; Adye, T; Adzic, P; Ajinenko, I; Albrecht, Z; Alderweireld, T; Alekseev, G D; Alemany, R; Allmendinger, T; Allport, P P; Almehed, S; Amaldi, Ugo; Amapane, N; Amato, S; Anassontzis, E G; Andersson, P; Andreazza, A; Andringa, S; Antilogus, P; Apel, W D; Arnoud, Y; Åsman, B; Augustin, J E; Augustinus, A; Baillon, Paul; Bambade, P; Barão, F; Barbiellini, Guido; Barbier, R; Bardin, Dimitri Yuri; Barker, G; Baroncelli, A; Battaglia, Marco; Baubillier, M; Becks, K H; Begalli, M; Behrmann, A; Beillière, P; Belokopytov, Yu A; Benekos, N C; Benvenuti, Alberto C; Bérat, C; Berggren, M; Bertini, D; Bertrand, D; Besançon, M; Bigi, M; Bilenky, S M; Bizouard, M A; Bloch, D; Blom, H M; Bonesini, M; Bonivento, W; Boonekamp, M; Booth, P S L; Borgland, A W; Borisov, G; Bosio, C; Botner, O; Boudinov, E; Bouquet, B; Bourdarios, C; Bowcock, T J V; Boyko, I; Bozovic, I; Bozzo, M; Branchini, P; Brenke, T; Brenner, R A; Brückman, P; Brunet, J M; Bugge, L; Buran, T; Burgsmüller, T; Buschbeck, Brigitte; Buschmann, P; Cabrera, S; Caccia, M; Calvi, M; Camporesi, T; Canale, V; Carena, F; Carroll, L; Caso, Carlo; Castillo-Gimenez, M V; Cattai, A; Cavallo, F R; Chabaud, V; Charpentier, P; Chaussard, L; Checchia, P; Chelkov, G A; Chierici, R; Shlyapnikov, P; Chochula, P; Chorowicz, V; Chudoba, J; Cieslik, K; Collins, P; Contri, R; Cortina, E; Cosme, G; Cossutti, F; Cowell, J H; Crawley, H B; Crennell, D J; Crépé, S; Crosetti, G; Cuevas-Maestro, J; Czellar, S; Davenport, Martyn; Da Silva, W; Deghorain, A; Della Ricca, G; Delpierre, P A; Demaria, N; De Angelis, A; de Boer, Wim; De Clercq, C; De Lotto, B; De Min, A; De Paula, L S; Dijkstra, H; Di Ciaccio, Lucia; Dolbeau, J; Doroba, K; Dracos, M; Drees, J; Dris, M; Duperrin, A; Durand, J D; Eigen, G; Ekelöf, T J C; Ekspong, Gösta; Ellert, M; Elsing, M; Engel, J P; Erzen, B; Espirito-Santo, M C; Falk, E; Fanourakis, G K; Fassouliotis, D; Fayot, J; Feindt, Michael; Ferrari, P; Ferrer, A; Ferrer-Ribas, E; Ferro, F; Fichet, S; Firestone, A; Flagmeyer, U; Föth, H; Fokitis, E; Fontanelli, F; Franek, B J; Frodesen, A G; Frühwirth, R; Fulda-Quenzer, F; Fuster, J A; Galloni, A; Gamba, D; Gamblin, S; Gandelman, M; García, C; Gaspar, C; Gaspar, M; Gasparini, U; Gavillet, P; Gazis, E N; Gelé, D; Gerdyukov, L N; Ghodbane, N; Gil, I; Glege, F; Gokieli, R; Golob, B; Gómez-Ceballos, G; Gonçalves, P; González-Caballero, I; Gopal, Gian P; Gorn, L; Górski, M; Guz, Yu; Gracco, Valerio; Grahl, J; Graziani, E; Green, C; Grimm, H J; Gris, P; Grosdidier, G; Grzelak, K; Günther, M; Guy, J; Hahn, F; Hahn, S; Haider, S; Hallgren, A; Hamacher, K; Hansen, J; Harris, F J; Hedberg, V; Heising, S; Hernández, J J; Herquet, P; Herr, H; Hessing, T L; Heuser, J M; Higón, E; Holmgren, S O; Holt, P J; Hoorelbeke, S; Houlden, M A; Hrubec, Josef; Huet, K; Hughes, G J; Hultqvist, K; Jackson, J N; Jacobsson, R; Jalocha, P; Janik, R; Jarlskog, C; Jarlskog, G; Jarry, P; Jean-Marie, B; Johansson, E K; Jönsson, P E; Joram, C; Juillot, P; Kapusta, F; Karafasoulis, K; Katsanevas, S; Katsoufis, E C; Keränen, R; Kersevan, Borut P; Khomenko, B A; Khovanskii, N N; Kiiskinen, A P; King, B J; Kinvig, A; Kjaer, N J; Klapp, O; Klein, H; Kluit, P M; Kokkinias, P; Koratzinos, M; Kostyukhin, V; Kourkoumelis, C; Kuznetsov, O; Kriznic, E; Krstic, P S; Krumshtein, Z; Kubinec, P; Kurowska, J; Kurvinen, K L; Lamsa, J; Lane, D W; Langefeld, P; Lapin, V; Laugier, J P; Lauhakangas, R; Leder, Gerhard; Ledroit, F; Lefébure, V; Leinonen, L; Leisos, A; Leitner, R; Lemonne, J; Lenzen, Georg; Lepeltier, V; Lesiak, T; Lethuillier, M; Libby, J; Liko, D; Lipniacka, A; Lippi, I; Lörstad, B; Loken, J G; Lopes, J H; López, J M; López-Fernandez, R; Loukas, D; Lutz, P; Lyons, L; MacNaughton, J N; Mahon, J R; Maio, A; Malek, A; Malmgren, T G M; Maltezos, S; Malychev, V; Mandl, F; Marco, J; Marco, R P; Maréchal, B; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Martínez-Rivero, C; Martínez-Vidal, F; Martí i García, S; Masik, J; Mastroyiannopoulos, N; Matorras, F; Matteuzzi, C; Matthiae, Giorgio; Mazzucato, F; Mazzucato, M; McCubbin, M L; McKay, R; McNulty, R; McPherson, G; Meroni, C; Meyer, W T; Myagkov, A; Migliore, E; Mirabito, L; Mitaroff, Winfried A; Mjörnmark, U; Moa, T; Moch, M; Møller, R; Mönig, K; Monge, M R; Moreau, X; Morettini, P; Morton, G A; Müller, U; Münich, K; Mulders, M; Mulet-Marquis, C; Muresan, R; Murray, W J; Muryn, B; Myatt, Gerald; Myklebust, T; Naraghi, F; Nassiakou, M; Navarria, Francesco Luigi; Navas, S; Nawrocki, K; Negri, P; Némécek, S; Neufeld, N; Neumeister, N; Nicolaidou, R; Nielsen, B S; Nikolenko, M; Nomokonov, V P; Normand, Ainsley; Nygren, A; Obraztsov, V F; Olshevskii, A G; Onofre, A; Orava, Risto; Orazi, G; Österberg, K; Ouraou, A; Paganoni, M; Paiano, S; Pain, R; Paiva, R; Palacios, J; Palka, H; Papadopoulou, T D; Papageorgiou, K; Pape, L; Parkes, C; Parodi, F; Parzefall, U; Passeri, A; Passon, O; Pegoraro, M; Peralta, L; Pernicka, Manfred; Perrotta, A; Petridou, C; Petrolini, A; Phillips, H T; Pierre, F; Pimenta, M; Piotto, E; Podobnik, T; Pol, M E; Polok, G; Poropat, P; Pozdnyakov, V; Privitera, P; Pukhaeva, N; Pullia, Antonio; Radojicic, D; Ragazzi, S; Rahmani, H; Ratoff, P N; Read, A L; Rebecchi, P; Redaelli, N G; Regler, Meinhard; Reid, D; Reinhardt, R; Renton, P B; Resvanis, L K; Richard, F; Rídky, J; Rinaudo, G; Røhne, O M; Romero, A; Ronchese, P; Rosenberg, E I; Rosinsky, P; Roudeau, Patrick; Rovelli, T; Royon, C; Ruhlmann-Kleider, V; Ruiz, A; Saarikko, H; Sacquin, Yu; Sadovskii, A; Sajot, G; Salt, J; Sampsonidis, D; Sannino, M; Schneider, H; Schwemling, P; Schwering, B; Schwickerath, U; Schyns, M A E; Scuri, F; Seager, P; Sedykh, Yu; Segar, A M; Sekulin, R L; Shellard, R C; Sheridan, A; Siebel, M; Simard, L C; Simonetto, F; Sissakian, A N; Smadja, G; Smirnova, O G; Smith, G R; Sokolov, A; Sopczak, André; Sosnowski, R; Spassoff, Tz; Spiriti, E; Sponholz, P; Squarcia, S; Stanescu, C; Stanic, S; Stevenson, K; Stocchi, A; Strauss, J; Strub, R; Stugu, B; Szczekowski, M; Szeptycka, M; Tabarelli de Fatis, T; Chikilev, O G; Tegenfeldt, F; Terranova, F; Thomas, J; Timmermans, J; Tinti, N; Tkatchev, L G; Todorova-Nová, S; Tomaradze, A G; Tomé, B; Tonazzo, A; Tortora, L; Tranströmer, G; Treille, D; Tristram, G; Trochimczuk, M; Troncon, C; Tsirou, A L; Turluer, M L; Tyapkin, I A; Tzamarias, S; Ullaland, O; Uvarov, V; Valenti, G; Vallazza, E; Van der Velde, C; van Apeldoorn, G W; van Dam, P; Van Doninck, W K; Van Eldik, J; Van Lysebetten, A; Van Remortel, N; Van Vulpen, I B; Vassilopoulos, N; Vegni, G; Ventura, L; Venus, W A; Verbeure, F; Verlato, M; Vertogradov, L S; Verzi, V; Vilanova, D; Vitale, L; Vlasov, E; Vodopyanov, A S; Vollmer, C F; Voulgaris, G; Vrba, V; Wahlen, H; Walck, C; Weiser, C; Wicke, D; Wickens, J H; Wilkinson, G R; Winter, M; Witek, M; Wolf, G; Yi, J; Yushchenko, O P; Zalewska-Bak, A; Zalewski, Piotr; Zavrtanik, D; Zevgolatakos, E; Zimin, N I; Zucchelli, G C; Zumerle, G
2000-01-01
The partial decay width $R_c$ of the $Z$ into $c\\bar{c}$ quark pair and the number of charm quarks $n_c$ per $b$ decay are measured with the DELPHI detector at \\mbox{LEP 1}. Particle identification provides clear $D^0$, $D^+$, $D_s^+$ and $\\Lambda_c^+$ signatures. The charm hadron production rate is measured in each channel by a fit to the scaled energy, impact parameter information and the invariant mass spectrum. Two measurements of $R_c$ are presented, from the $D^{*+}$ production rate and from the overall charm counting, including strange charm baryon production, in $c\\bar{c}$ events. The multiplicity $n_c$, which includes hidden $c\\bar{c}$ and strange charm baryon production, is inferred from the charm counting in $b\\bar{b}$ events. The final results are $R_c = 0.1665 \\pm 0.0095$ and $n_c = 1.166 \\pm 0.086$.
Dowdall, R J; Davies, C T H; Horgan, R R; Monahan, C J; Shigemitsu, J
2013-05-31
We present the first lattice QCD calculation of the decay constants f(B) and f(B(s)) with physical light quark masses. We use configurations generated by the MILC Collaboration including the effect of u, d, s, and c highly improved staggered quarks in the sea at three lattice spacings and with three u/d quark mass values going down to the physical value. We use improved nonrelativistic QCD (NRQCD) for the valence b quarks. Our results are f(B)=0.186(4) GeV, f(B(s))=0.224(4) GeV, f(B(s))/f(B)=1.205(7), and M(B(s))-M(B)=85(2) MeV, superseding earlier results with NRQCD b quarks. We discuss the implications of our results for the standard model rates for B((s))→μ(+)μ(-) and B→τν. PMID:23767714
Quark-gluon plasma at finite baryon density: A large-N/sub c/ approach
International Nuclear Information System (INIS)
A simple model for the quark-gluon plasma with a nonzero baryon number B is developed in a microcanonical (i.e., fixed B) approach. The model exhibits features which one expects will emerge from a nonperturbative treatment of QCD. We show the existence of a critical chemical potential μ/sub c/ such that, for T>0, physical properties are unaffected by chemical potentials μ when chemical bondμchemical bond<μ/sub c/. μ/sub c/ therefore resembles a mass gap
Quark-gluon plasma at finite baryon density: A large-N/sub c/ approach
Energy Technology Data Exchange (ETDEWEB)
Azakov, S.I.; Salomonson, P.; Skagerstam, B.h.
1987-10-01
A simple model for the quark-gluon plasma with a nonzero baryon number B is developed in a microcanonical (i.e., fixed B) approach. The model exhibits features which one expects will emerge from a nonperturbative treatment of QCD. We show the existence of a critical chemical potential ..mu../sub c/ such that, for T>0, physical properties are unaffected by chemical potentials ..mu.. when chemically bond..mu..chemically bond<..mu../sub c/. ..mu../sub c/ therefore resembles a mass gap.
Monteiro, Antony Prakash; Kumar, K B Vijaya
2016-01-01
The complete spectrum of $c\\bar{b}$ states is obtained in a phenomenological non relativistic quark model(NRQM), which consists of a confinement potential and one gluon exchange potential (OGEP) as effective quark - antiquark potential. We make predictions for the radiative decay (E1 and M1) widths and weak decay widths of $c\\bar{b}$ states in the framework of NRQM formalism.
Form factors of ηc in light-front quark model
International Nuclear Information System (INIS)
We study the form factors of the ηc meson in the light-front quark model. We explicitly show that the transition form factor of ηc → γ*γ as a function of the momentum transfer is consistent with the experimental data by the BaBar collaboration, while the decay constant of ηc is found to be fηc = 230.5+52.2-61.0 and 303.6+115.2-116.4 MeV for ηc ∝ c anti c by using two ηc → γγ decay widths of 5.3 ± 0.5 and 7.2 ± 2.1 keV, given by Particle Data Group and Lattice QCD calculation, respectively. (orig.)
Form factors of {eta}{sub c} in light-front quark model
Energy Technology Data Exchange (ETDEWEB)
Geng, Chao-Qiang [Chongqing University of Posts and Telecommunications, College of Mathematics and Physics, Chongqing (China); National Center for Theoretical Sciences, Physics Division, Hsinchu (China); National Tsing Hua University, Department of Physics, Hsinchu (China); Lih, Chong-Chung [Shu-Zen College of Medicine and Management, Department of Optometry, Kaohsiung Hsien (China); National Center for Theoretical Sciences, Physics Division, Hsinchu (China); National Tsing Hua University, Department of Physics, Hsinchu (China)
2013-08-15
We study the form factors of the {eta}{sub c} meson in the light-front quark model. We explicitly show that the transition form factor of {eta}{sub c} {yields} {gamma}{sup *}{gamma} as a function of the momentum transfer is consistent with the experimental data by the BaBar collaboration, while the decay constant of {eta}{sub c} is found to be f{sub {eta}{sub c}} = 230.5{sup +52.2}{sub -61.0} and 303.6{sup +115.2}{sub -116.4} MeV for {eta}{sub c} {proportional_to} c anti c by using two {eta}{sub c} {yields} {gamma}{gamma} decay widths of 5.3 {+-} 0.5 and 7.2 {+-} 2.1 keV, given by Particle Data Group and Lattice QCD calculation, respectively. (orig.)
Compatibility of Quark and Resonant Picture Excited Baryon Multiplets in 1/N_c
Cohen, T D; Cohen, Thomas D.; Lebed, Richard F.
2003-01-01
We demonstrate that the two major complementary pictures of large N_c baryon resonances--as single-quark orbital excitations about a closed-shell core [giving SU(2N_F) x O(3) multiplets], and as resonances in meson-baryon scattering amplitudes--are completely compatible in a specific sense: Both pictures give rise to a set of multiplets of degenerate states, for which any complete spin-flavor multiplet within one picture fills the quantum numbers of complete multiplets in the other picture. This result is demonstrated by: (i) straightforward computation of the lowest multiplets in both pictures; (ii) a study of the nature of quark excitations in a hedgehog picture; (iii) direct group-theoretical comparison of the constraints in the two pictures.
Heavy quark symmetry and weak decays of the $b$-baryons in pentaquarks with a $c\\bar{c}$ component
Ali, Ahmed; Aslam, M Jamil; Rehman, Abdur
2016-01-01
The discovery of the baryonic states $P_c^+(4380)$ and $P_c^+(4450)$ by the LHCb collaboration has evoked a lot of theoretical interest. These states have the minimal quark content $c \\bar{c} u u d$. Interpreted as hidden charm diquark-diquark-antiquark baryons, the assigned spin and angular momentum quantum numbers are $P_c^+(4380)= \\{\\bar{c} [cu]_{s=1} [ud]_{s=1}; L_{\\mathcal{P}}=0, J^{\\rm P}=\\frac{3}{2}^- \\}$ and $P_c^+(4450)= \\{\\bar{c} [cu]_{s=1} [ud]_{s=0}; L_{\\mathcal{P}}=1, J^{\\rm P}=\\frac{5}{2}^+ \\}$, where $s=0,1$ are the spins of the diquarks and $L_{\\mathcal{P}}=0,1$ are the orbital angular momentum quantum numbers of the pentaquarks. We point out that heavy quark symmetry allows only the higher mass pentaquark state $P_c^+(4450)$ having $[ud]_{s=0}$ to be produced in $\\Lambda_b^0$ decays, whereas the lower mass state $P_c^+(4380)$ having $[ud]_{s=1}$ is disfavored. Pentaquark spectrum is rich enough to accommodate a $J^P=\\frac{3}{2}^-$ state, which has the correct light diquark spin $\\{\\bar{c} [cu...
Colorless quark-gluon gas in the limit of large N sub c
Energy Technology Data Exchange (ETDEWEB)
Azakov, S.I.
1989-03-01
A quark-gluon gas in a finite volume with global internal symmetry group SU(N{sub c}) on the states of which the condition of being colorless is imposed is studied in the limit N{sub c} {yields} {infinity}. It is shown that without allowance for the conservation law of the baryon charge this system undergoes a phase transition of the third kind. However, in the more realistic situation in which this conservation law is taken into account there is no phase transition.
Numerical simulation of QCD with u, d, s and c quarks in the twisted-mass Wilson formulation
International Nuclear Information System (INIS)
A first study of numerical Monte Carlo simulations with two quark doublets, a mass-degenerate one and a mass-split one, interpreted as u, d, s and c quarks, is carried out in the framework of the twisted mass Wilson lattice formulation. Tuning the bare parameters of this theory is explored on 123.24 and 163.32 lattices at lattice spacings a ≅0.20 fm and a ≅0.15 fm, respectively. (Orig.)
Baryogenesis of the Universe in cSMCS Model plus Iso-Doublet Vector Quark
Darvishi, Neda
2016-01-01
CP violation of the SM is insufficient to explain the baryon asymmetry in the universe and therefore an additional source of CP violation is needed. Here the extension of the SM by a neutral complex scalar singlet with a nonzero vacuum expectation value (cSMCS) plus a heavy vector quark pair is considered. This model offers the spontaneous CP violation and proper description in the baryogenesis, it leads strong enough first-order electro-weak phase transition to suppress the baryon-violating sphaleron process.
Matagne, N
2011-01-01
We show that the two complementary pictures of large $N_c$ baryons - the single-quark orbital excitation about a symmetric core and the meson-nucleon resonance -- are compatible for $\\ell$ = 3 SU(4) baryons. The proof is based on a simple Hamiltonian including operators up to order $\\mathcal{O}(N^0_c)$ used previously in the literature for $\\ell$ = 1.
Pentaquark Θ+, constituent quark structures, and prediction of charmed Θc0 and bottomed Θb+
International Nuclear Information System (INIS)
The newly observed Θ+ resonance is believed to be a pentaquark with the constituent quarks uudds-bar. There are a few options for the constituent quark structure. Some advocate diquark-diquark-antiquark (ud)-(ud)-s-bar while others favor diquark-triquark (ud)-(uds-bar) structure. We use the color-spin hyperfine interaction to examine the energy levels of these structures, and we find that the diquark-diquark-antiquark structure is slightly favored. We proceed to write down the flavor triplet and antisextet of the charmed or bottomed exotic baryons with internal qqqqQ-bar quarks. We also estimate the mass of Θc0 and Θb+
Density of Saturated Nuclear Matter at Large $N_{c}$ and Heavy Quark Mass Limits
Adhikari, Prabal; Datta, Ishaun
2013-01-01
We exhibit the existence of stable, saturated nuclear matter in the large $N_{c}$ and heavy quark mass limits of QCD. In this limit, baryons (with the same spin flavor structure) interact at leading order in $N_{c}$ via a repulsive interaction due to the Pauli exclusion principle and at subleading order in $1/N_c$ via the exchange of glueballs. Assuming that the lightest glueball is a scalar, which implies that the subleading baryon interaction is attractive, we find that nuclear matter saturates since the subleading attractive interaction is longer ranged than the leading order repulsive one. We find that the saturated matter is in the form of a crystal with either a face-centered cubic or a hexagonal-close-packed symmetry with baryon densities of $\\mathcal{O}((\\, \\tilde{\\alpha}_{s} m_q (\\ln (N_{c}m_{q}\\Lambda_{\\textrm{QCD}}^{-1}))^{-1})^3 )$. Remarkably, the leading order expression for the density of saturated nuclear matter is independent of the lighest glueball mass and scalar-glueball-baryon coupling in...
Dynamical Color Correlations in a $SU(2)_c$ Quark Exchange Model of Nuclear Matter
Gardner, S; Piekarewicz, J
1994-01-01
The quark exchange model is a simple realization of an adiabatic approximation to the strong-coupling limit of Quantum Chromodynamics (QCD): the quarks always coalesce into the lowest energy set of flux tubes. Nuclear matter is thus modeled in terms of its quarks. We wish to study the correlations imposed by total wavefunction antisymmetry when color degrees of freedom are included. To begin with, we have considered one-dimensional matter with a $SU(2)$ color internal degree of freedom only. We proceed by constructing a totally antisymmetric, color singlet {\\it Ansatz} characterized by a variational parameter $\\lambda$ (which describes the length scale over which two quarks in the system are clustered into hadrons) and by performing a variational Monte Carlo calculation of the energy to optimize $\\lambda$ for a fixed density. We calculate the $q-q$ correlation function as well, and discuss the qualitative differences between the system at low and high density.
Gilani, Amjad Hussain Shah
2005-01-01
There are eight quarks in each family and there are three families of quarks i.e. c, b, t. Also, we propose similar structure for leptons. The nature of strong force is named as `third order electroweak'.
Abreu, P; Adzic, P; Albrecht, Z; Alderweireld, T; Alekseev, G D; Alemany, R; Allmendinger, T; Allport, P P; Almehed, S; Amaldi, Ugo; Amato, S; Anassontzis, E G; Andersson, P; Andreazza, A; Andringa, S; Antilogus, P; Apel, W D; Arnoud, Y; Åsman, B; Augustin, J E; Augustinus, A; Baillon, Paul; Bambade, P; Barão, F; Barbiellini, Guido; Barbier, R; Bardin, Dimitri Yuri; Barker, G; Baroncelli, A; Battaglia, Marco; Baubillier, M; Becks, K H; Begalli, M; Beillière, P; Belokopytov, Yu A; Belous, K S; Benvenuti, Alberto C; Bérat, C; Berggren, M; Bertini, D; Bertrand, D; Besançon, M; Bianchi, F; Bigi, M; Bilenky, S M; Bizouard, M A; Bloch, D; Blom, H M; Bonesini, M; Bonivento, W; Boonekamp, M; Booth, P S L; Borgland, A W; Borisov, G; Bosio, C; Botner, O; Boudinov, E; Bouquet, B; Bourdarios, C; Bowcock, T J V; Boyko, I; Bozovic, I; Bozzo, M; Branchini, P; Brenke, T; Brenner, R A; Brückman, P; Brunet, J M; Bugge, L; Buran, T; Burgsmüller, T; Buschmann, P; Cabrera, S; Caccia, M; Calvi, M; Camporesi, T; Canale, V; Carena, F; Carroll, L; Caso, Carlo; Castillo-Gimenez, M V; Cattai, A; Cavallo, F R; Chabaud, V; Chapkin, M M; Charpentier, P; Chaussard, L; Checchia, P; Chelkov, G A; Chierici, R; Chliapnikov, P V; Chochula, P; Chorowicz, V; Chudoba, J; Cieslik, K; Collins, P; Contri, R; Cortina, E; Cosme, G; Cossutti, F; Cowell, J H; Crawley, H B; Crennell, D J; Crépé, S; Crosetti, G; Cuevas-Maestro, J; Czellar, S; Davenport, Martyn; Da Silva, W; Deghorain, A; Della Ricca, G; Delpierre, P A; Demaria, N; De Angelis, A; de Boer, Wim; De Brabandere, S; De Clercq, C; De Lotto, B; De Min, A; De Paula, L S; Dijkstra, H; Di Ciaccio, Lucia; Dolbeau, J; Doroba, K; Dracos, M; Drees, J; Dris, M; Duperrin, A; Durand, J D; Eigen, G; Ekelöf, T J C; Ekspong, Gösta; Ellert, M; Elsing, M; Engel, J P; Erzen, B; Espirito-Santo, M C; Falk, E; Fanourakis, G K; Fassouliotis, D; Fayot, J; Feindt, Michael; Fenyuk, A; Ferrari, P; Ferrer, A; Ferrer-Ribas, E; Fichet, S; Firestone, A; Flagmeyer, U; Föth, H; Fokitis, E; Fontanelli, F; Franek, B J; Frodesen, A G; Frühwirth, R; Fulda-Quenzer, F; Fuster, J A; Galloni, A; Gamba, D; Gamblin, S; Gandelman, M; García, C; Gaspar, C; Gaspar, M; Gasparini, U; Gavillet, P; Gazis, E N; Gelé, D; Ghodbane, N; Gil, I; Glege, F; Gokieli, R; Golob, B; Gómez-Ceballos, G; Gonçalves, P; González-Caballero, I; Gopal, Gian P; Gorn, L; Górski, M; Guz, Yu; Gracco, Valerio; Grahl, J; Graziani, E; Green, C; Grimm, H J; Gris, P; Grosdidier, G; Grzelak, K; Günther, M; Guy, J; Hahn, F; Hahn, S; Haider, S; Hallgren, A; Hamacher, K; Hansen, J; Harris, F J; Hedberg, V; Heising, S; Hernández, J J; Herquet, P; Herr, H; Hessing, T L; Heuser, J M; Higón, E; Holmgren, S O; Holt, P J; Hoorelbeke, S; Houlden, M A; Hrubec, Josef; Huet, K; Hughes, G J; Hultqvist, K; Jackson, J N; Jacobsson, R; Jalocha, P; Janik, R; Jarlskog, C; Jarlskog, G; Jarry, P; Jean-Marie, B; Johansson, E K; Jönsson, P E; Joram, C; Juillot, P; Kapusta, F; Karafasoulis, K; Katsanevas, S; Katsoufis, E C; Keränen, R; Kersevan, Borut P; Khomenko, B A; Khovanskii, N N; Kiiskinen, A P; King, B J; Kinvig, A; Kjaer, N J; Klapp, O; Klein, H; Kluit, P M; Kokkinias, P; Koratzinos, M; Kostyukhin, V; Kourkoumelis, C; Kuznetsov, O; Krammer, Manfred; Kriznic, E; Krstic, J; Krumshtein, Z; Kubinec, P; Kurowska, J; Kurvinen, K L; Lamsa, J; Lane, D W; Langefeld, P; Lapin, V; Laugier, J P; Lauhakangas, R; Leder, Gerhard; Ledroit, F; Lefébure, V; Leinonen, L; Leisos, A; Leitner, R; Lemonne, J; Lenzen, Georg; Lepeltier, V; Lesiak, T; Lethuillier, M; Libby, J; Liko, D; Lipniacka, A; Lippi, I; Lörstad, B; Loken, J G; Lopes, J H; López, J M; López-Fernandez, R; Loukas, D; Lutz, P; Lyons, L; MacNaughton, J N; Mahon, J R; Maio, A; Malek, A; Malmgren, T G M; Malychev, V; Mandl, F; Marco, J; Marco, R P; Maréchal, B; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Martínez-Rivero, C; Martínez-Vidal, F; Martí i García, S; Mastroyiannopoulos, N; Matorras, F; Matteuzzi, C; Matthiae, Giorgio; Masik, J; Mazzucato, F; Mazzucato, M; McCubbin, M L; McKay, R; McNulty, R; McPherson, G; Meroni, C; Meyer, W T; Migliore, E; Mirabito, L; Mitaroff, Winfried A; Mjörnmark, U; Moa, T; Moch, M; Møller, R; Mönig, K; Monge, M R; Moreau, X; Morettini, P; Morton, G A; Müller, U; Münich, K; Mulders, M; Mulet-Marquis, C; Muresan, R; Murray, W J; Muryn, B; Myatt, Gerald; Myklebust, T; Naraghi, F; Navarria, Francesco Luigi; Navas, S; Nawrocki, K; Negri, P; Némécek, S; Neufeld, N; Neumeister, N; Nicolaidou, R; Nielsen, B S; Nikolenko, M; Nomokonov, V P; Normand, Ainsley; Nygren, A; Obraztsov, V F; Olshevskii, A G; Onofre, A; Orava, Risto; Orazi, G; Österberg, K; Ouraou, A; Paganoni, M; Paiano, S; Pain, R; Paiva, R; Palacios, J; Palka, H; Papadopoulou, T D; Papageorgiou, K; Pape, L; Parkes, C; Parodi, F; Parzefall, U; Passeri, A; Passon, O; Pegoraro, M; Peralta, L; Pernicka, Manfred; Perrotta, A; Petridou, C; Petrolini, A; Phillips, H T; Pierre, F; Pimenta, M; Piotto, E; Podobnik, T; Pol, M E; Polok, G; Poropat, P; Pozdnyakov, V; Privitera, P; Pukhaeva, N; Pullia, Antonio; Radojicic, D; Ragazzi, S; Rahmani, H; Rakoczy, D; Ratoff, P N; Read, A L; Rebecchi, P; Redaelli, N G; Regler, Meinhard; Reid, D; Reinhardt, R; Renton, P B; Resvanis, L K; Richard, F; Rídky, J; Rinaudo, G; Røhne, O M; Romero, A; Ronchese, P; Rosenberg, E I; Rosinsky, P; Roudeau, Patrick; Rovelli, T; Royon, C; Ruhlmann-Kleider, V; Ruiz, A; Saarikko, H; Sacquin, Yu; Sadovskii, A; Sajot, G; Salt, J; Sampsonidis, D; Sannino, M; Schneider, H; Schwemling, P; Schwickerath, U; Schyns, M A E; Scuri, F; Seager, P; Sedykh, Yu; Segar, A M; Sekulin, R L; Shellard, R C; Sheridan, A; Siebel, M; Simard, L C; Simonetto, F; Sissakian, A N; Smadja, G; Smirnov, N; Smirnova, O G; Smith, G R; Sopczak, André; Sosnowski, R; Spassoff, Tz; Spiriti, E; Sponholz, P; Squarcia, S; Stampfer, D; Stanescu, C; Stanic, S; Stevenson, K; Stocchi, A; Strauss, J; Strub, R; Stugu, B; Szczekowski, M; Szeptycka, M; Tabarelli de Fatis, T; Tegenfeldt, F; Terranova, F; Thomas, J; Timmermans, J; Tinti, N; Tkatchev, L G; Todorova-Nová, S; Tomaradze, A G; Tomé, B; Tonazzo, A; Tortora, L; Tranströmer, G; Treille, D; Tristram, G; Trochimczuk, M; Troncon, C; Tsirou, A L; Turluer, M L; Tyapkin, I A; Tzamarias, S; Überschär, B; Ullaland, O; Uvarov, V; Valenti, G; Vallazza, E; van Apeldoorn, G W; van Dam, P; Van Doninck, W K; Van Eldik, J; Van Lysebetten, A; Van Vulpen, I B; Vassilopoulos, N; Vegni, G; Ventura, L; Venus, W A; Verbeure, F; Verlato, M; Vertogradov, L S; Verzi, V; Vilanova, D; Vitale, L; Vlasov, E; Vodopyanov, A S; Vollmer, C F; Voulgaris, G; Vrba, V; Wahlen, H; Walck, C; Weiser, C; Wicke, D; Wickens, J H; Wilkinson, G R; Winter, M; Witek, M; Wolf, G; Yi, J; Yushchenko, O P; Zaitsev, A; Zalewska-Bak, A; Zalewski, Piotr; Zavrtanik, D; Zevgolatakos, E; Zimin, N I; Zucchelli, G C; Zumerle, G
1999-01-01
A measurement of the forward--backward asymmetry of $e^{+}e^{-} \\to c\\bar{c}$ and $e^{+}e^{-} \\to b\\bar{b}$ on the $Z$ resonance is performed using about 3.5 million hadronic $Z$ decays collected by the DELPHI detector at LEP in the years 1992 to 1995. The heavy quark is tagged by the exclusive reconstruction of several $D$ meson decay modes. The forward--backward asymmetries for $c$ and $b$ quarks at the $Z$ resonance are determined to be: \\[ \\renewcommand{\\arraystretch}{1.6} \\begin{array}{rcr@{\\!\\!\\;\\,}l} \\Afbc(\\sqrt{s} = 91.235 \\, {\\rm GeV}) &=& &0.0659\\,\\, \\pm\\,\\, 0.0094\\, (stat)\\,\\, \\pm\\,\\, 0.0035\\, (syst) \\\\ \\Afbb (\\sqrt{s} = 91.235 \\, {\\rm GeV}) &=& &0.0762\\,\\, \\pm\\,\\, 0.0194\\, (stat)\\,\\, \\pm\\,\\, 0.0085\\, (syst) \\\\ \\Afbc(\\sqrt{s} = 89.434\\, {\\rm GeV}) &=&-&0.0496\\,\\, \\pm\\,\\, 0.0368\\, (stat)\\,\\, \\pm\\,\\, 0.0053\\, (syst) \\\\ \\Afbb(\\sqrt{s} = 89.434\\, {\\rm GeV}) &=& &0.0567\\,\\, \\pm\\,\\, 0.0756\\, (stat)\\,\\, \\pm\\,\\ 0.0117\\, (syst) \\\\ \\Afbc(\\sqrt{s} = 92.990\\, {\\r...
The mixed quark-gluon condensate from an effective quark-quark interaction
Meissner, Thomas
1997-01-01
We exhibit the method for obtaining non perturbative quark and gluonic vacuum condensates from a model truncation of QCD. The truncation allows for a phenomenological description of the quark-quark interaction in a framework which maintains all global symmetries of QCD and allows an 1/N_c expansion. Within this approach the functional integration over the gluon fields can be performed and therefore any gluonic vacuum observable can be expressed in terms of a quark operator and the gluon propa...
International Nuclear Information System (INIS)
The most important particle accelerators that can contribute to quark production efforts are overviewed. The history of the discovery of quark particles is outlined. The so-called y-particles were found with 9460 MeV mass in 1977, the new particle was called beauty quark. The tau-particles were discovered in 1975. The most important features of the new generation of particles, the quark family are discussed. (R.P.)
Samart, Daris; Yan, Yupeng
2016-01-01
We construct, in the work, chiral $SU(3)$ Lagrangian with $D$ mesons of spin $J^P=0^-$ and $J^P=1^-$ and charmed baryons of spin $J^P=1/2^+$ and $J^P=3/2^+$. There are 42 leading two-body counter-terms involving two charmed baryon fields and two $D$ meson fields in the constructed Lagrangian. The heavy-quark spin symmetry leads to 35 sum rules while the large-$N_c$ operator analysis predicts 29 ones at the next-to leading order of $1/N_c$ expansion. The combination of the sum rules from both the heavy-quark symmetry and the large-$N_c$ analysis results in 38 independent sum rules which reduces the number of free parameters in the chiral Lagrangian down to 4 only. This is a remarkable result demonstrating the consistency of the heavy-quark symmetry and large-$N_c$ operator analysis.
Jido, Daisuke; Sakashita, Minori
2016-08-01
The possibility of having a diquark configuration in heavy baryons, such as Λ and Λ, is examined by a nonrelativistic potential model with a heavy quark and a light scalar diquark. Assuming that the Λ and Λ baryons are composed of the heavy quark and the point-like scalar-isoscalar ud diquark, we solve the two-body Schrödinger equation with the Coulomb plus linear potential and obtain the energy spectra for the heavy baryons. Contrary to our expectation, it is found that the potential determined by the quarkonium spectra fails to reproduce the excitation spectra of the Λ and Λ in the quark-diquark picture, while the Λ and Λ spectra are reproduced with half the strength of the confinement string tension than for the quarkonium. The finite size effect of the diquark is also examined and it is found that the introduction of a finite size diquark would resolve the failure of the spectrum reproduction. The Ξ excitation energy is also calculated and is found to be smaller than Λ in the quark-diquark model. This is not consistent with experimental observations.
Multileptons from heavy quarks
International Nuclear Information System (INIS)
The paper is concerned with a brief look at the various multilepton signals that are expected at p-barp colliders from the production and cascade decay of top quarks, plus the backgrounds from b and c production. (author)
International Nuclear Information System (INIS)
Experimental results which proved the reality of quarks are reviewed along with further experiments broadening the representation of quarks and leptons and providing the basis to develop the theory of elementary particles. The discovery of the J/psi particle is noted to give rise to the discovery of c-quark, the existance of which is confirmed by the discovery of charmed hadrons. The main aspects of quantum chromodynamics explaining the mechanism of strong interaction of quarks are considered along with those of the Weinberg-Salam theory proposed to describe weak and electromagnetic interactions of quarks and leptons. Experimental data testifying to the existance of heavy tausup(+-) leptons are presented. The history of discovery of γ mesons and of a new heavier b-quark is described. Perspectives for studying elementary particles are discussed. Further studies of γ mesons, discovery and investigation of charmed particles are noted to be immediate tasks along with the search for manifestation of t-quark considered to be a partner of b-quark from the viewpoint of the Weinberg-Salam model
Quark spin and quark orbital angular momentum content of the proton
Energy Technology Data Exchange (ETDEWEB)
Li, B.A. [Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506 (United States)
1995-09-01
In a quark-meson theory it is found that the smallness of quark spin content and strong strange quark polarization can be understood by the anomaly and large {ital N}{sub {ital c}} expansion very well. It has been proved in this theory that the proton spin is mostly carried by quark orbital angular momentum. {copyright} {ital 1995 American Institute of Physics.}
Gutsche, Thomas; Korner, Jurgen G; Lyubovitskij, Valery E; Santorelli, Pietro; Habyl, Nurgul
2015-01-01
Recently there has been much interest in the tauonic semileptonic meson decays B -> D+ tau + nu_tau and B -> D* + tau + nu_tau where one has found larger rates than what is predicted by the Standard Model. We analyze the corresponding semileptonic baryon decays Lambda_b(0) -> Lambda_c(+) + tau(-) + antinu_tau with particular emphasis on the lepton helicity flip and scalar contributions which vanish for zero lepton masses. We calculate the total rate, differential decay distributions, the longitudinal and transverse polarization of the daughter baryon Lambda_c(+) and the tau-lepton, and the lepton-side forward-backward asymmetries. The nonvanishing polarization of the daughter baryon Lambda_c(+) leads to hadron-side asymmetries in e.g. the decay Lambda_c(+) -> Lambda(0) + pi(+) and azimuthal correlations between the two final state decay planes which we specify. We provide numerical results on these observables using results of the covariant confined quark model. We find large lepton mass effects in the q2-spe...
Quark matter symmetry energy and quark stars
Chu, Peng-Cheng; Chen, Lie-Wen
2012-01-01
We extend the confined-density-dependent-mass (CDDM) model to include isospin dependence of the equivalent quark mass. Within the confined-isospin-density-dependent-mass (CIDDM) model, we study the quark matter symmetry energy, the stability of strange quark matter, and the properties of quark stars. We find that including isospin dependence of the equivalent quark mass can significantly influence the quark matter symmetry energy as well as the properties of strange quark matter and quark sta...
Eberl, H; Bartl, A; Hidaka, K; Majerotto, W
2016-01-01
We calculate the decay width of h0 -> b bbar in the Minimal Supersymmetric Standard Model (MSSM) with quark flavour violation (QFV) at full one-loop level. We study the effect of scarm-stop mixing and sstrange-sbottom mixing taking into account the constraints from the B meson data. We discuss and compare in detail the decays h0 -> c cbar and h0 -> b bbar within the framework of the perturbative mass insertion technique using the Flavour Expansion Theorem. The deviation of both decay widths from the Standard Model values can be quite large. Whereas in h0 -> c cbar it is almost entirely due to the flavour violating part of the MSSM, in h0 -> b bbar it is mainly due to the flavour conserving part. Nevertheless, the QFV contribution to Gamma(h0 -> b bbar) due to scarm-stop mixing and chargino exchange can go up to about 8%.
Systematic study of $Z^+_c$ family from quark model's perspective
Deng, Chengrong; Huang, Hongxia; Wang, Fan
2015-01-01
Inspired by the present experimental status of charged charmonium-like states $Z_c^+$, the tetraquark states $[cu][\\bar{c}\\bar{d}]$ are systematically studied in a color flux-tube model with a multi-body confinement potential. The investigation indicates that charged charmonium-like states $Z_c^+(3900)$ or $Z_c^+(3885)$, $Z_c^+(3930)$, $Z_c^+(4020)$ or $Z_c^+(4025)$, $Z_1^+(4050)$, $Z_2^+(4250)$, and $Z_c^+(4200)$ can be uniformly described as tetraquark states $[cu][\\bar{c}\\bar{d}]$ with the quantum numbers $n^{2S+1}L_J$ and $J^P$ of $1^{3}S_1$ and $1^+$, $2^{3}S_1$ and $1^+$, $1^5S_2$ and $2^+$, $1^3P_1$ and $1^-$, $1^5D_1$ and $1^+$, and $1^3D_1$ and $1^+$, respectively. The predicted lowest charged tetraquark state $[cu][\\bar{c}\\bar{d}]$ with $0^+$ and $1^1S_0$ has a energy of $3780\\pm10$ MeV in the model. The tetraquark states are compact three-dimensional spatial configurations similar to a rugby ball, the higher orbital angular momentum $L$ between the diquark $[cu]$ and antidiquark $[\\bar{c}\\bar{d}]$,...
Heavy quark distribution function in hadrons
Oganesian, A. G.
2008-01-01
The moments of the heavy quark-parton distribution functions in a heavy pseudoscalar meson, obtained in QCD sum rules, are expanded in the inverse heavy quark. Comparison with the finite mass results reveals that while the heavy mass expansion works reasonably well for the $b$ quark, one has to take into account terms of higher than $(1/m_c)^2$ order for the $c$ quark.
Top Quark Flavor Changing Decay t → cH0 in Little Higgs Model
Institute of Scientific and Technical Information of China (English)
Farshid Tabbakh; LIU Jing-Jing; MA Wen-Gan; ZHANG Ren-You; HOU Hong-Sheng
2005-01-01
We study theoretically the quantum effects of the littlest Higgs model (LH) mediated by flavor changing one-loop Feynman diagrams on the rare decay process t → cH0. The comparison of the decay width in the LH model with that in the standard model (SM) is made. We find that the decay branch ratio of t → cH0 in the LH model is at most of the order ～ 10-12, which is two order larger than in the SM. The numerical results show that the difference between the branch ratios in the LH model and the SM is generally sensitive to the LH model parameters, such as symmetry breaking scale f, Higgs boson mass mH0, and x = v'4f /v2 in our chosen parameter space, but relatively insensitive to the value choice of the cosine of the mixing angle c and the ratio λ1/λ2.
International Nuclear Information System (INIS)
Feynman x distributions and transverse momentum pT distributions for the inclusive reactions pp → h±, π0, K-s0 Λ0, anti Λ0, K*±, Σ*± + anything at 360 GeV/c are analyzed in terms of the quark-diquark fragmentation models. Comparison of the model predictions with inclusive data reveals that the model with diquarks can quantitatively describe all data. In particular for the baryon production such as pp → Λ0 + anything, the model without diquarks shows serious discrepancies with the data. Using the quark-diquark fragmentation model, we have found that the primordial transverse momentum T> ≅ 0.6 GeV/c can well reproduce pT2 distributions and the Feynman x-pT correlations. (author)
Bootstrapping quarks and gluons
International Nuclear Information System (INIS)
Dual topological unitarization (DTU) - the approach to S-matrix causality and unitarity through combinatorial topology - is reviewed. Amplitudes associated with triangulated spheres are shown to constitute the core of particle physics. Each sphere is covered by triangulated disc faces corresponding to hadrons. The leading current candidate for the hadron-face triangulation pattern employs 3-triangle basic subdiscs whose orientations correspond to baryon number and topological color. Additional peripheral triangles lie along the hadron-face perimeter. Certain combinations of peripheral triangles with a basic-disc triangle can be identified as quarks, the flavor of a quark corresponding to the orientation of its edges that lie on the hadron-face perimeter. Both baryon number and flavor are additively conserved. Quark helicity, which can be associated with triangle-interior orientation, is not uniformly conserved and interacts with particle momentum, whereas flavor does not. Three different colors attach to the 3 quarks associated with a single basic subdisc, but there is no additive physical conservation law associated with color. There is interplay between color and quark helicity. In hadron faces with more than one basic subdisc, there may occur pairs of adjacent flavorless but colored triangles with net helicity +-1 that are identifiable as gluons. Broken symmetry is an automatic feature of the bootstrap. T, C and P symmetries, as well as up-down flavor symmetry, persist on all orientable surfaces
International Nuclear Information System (INIS)
We discuss the results accumulated during the last five years in heavy quark physics and try to draw a simple general picture of the present situation. The survey is based on a unified point of view resulting from quantum chromodynamics. (orig.)
International Nuclear Information System (INIS)
Inclusive production of rho0 and f is studied in anti pp interactions at 12 GeV/c. The cross sections for rho0 and f are found to be 6.7 +- 0.3 mb and 1.4 +- 0.3 mb, respectively. The inclusive cross sections are presented as functions of c.m. rapidity, Feynman x and p2sub(T). The data are compared with the predictions of the quark fusion model which is found to give a reasonable description of the experimental features. (author)
Prospects for the measurement of the Higgs Yukawa couplings to b and c quarks, and muons at CLIC
Czech Academy of Sciences Publication Activity Database
Grefe, C.; Laštovička, Tomáš; Strube, J.
2013-01-01
Roč. 73, č. 2 (2013), s. 1-7. ISSN 1434-6044 Institutional support: RVO:68378271 Keywords : Higgs * branching * ratio * Yukawa * couplings * quarks * muons * CLIC * inear collider Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 5.436, year: 2013
Measurements of top quark properties at CDF
Energy Technology Data Exchange (ETDEWEB)
Kraan, Aafke C.; /Pennsylvania U.
2006-11-01
The top quark with its mass of about 172 GeV/c{sup 2} is the most massive fundamental particle observed by experiment. In this talk they highlight the most recent measurements of several top quark properties performed with the CDF detector based on data samples corresponding to integrated luminosities up to 1 fb{sup -1}. These results include a search for top quark pair production via new massive resonances, measurements of the helicity of the W boson from top-quark decay, and a direct limit on the lifetime of the top quark.
Mass spectra of doubly heavy baryons in the relativistic quark model
Ebert, D; Faustov, R. N.; Galkin, V. O.; Martynenko, A. P.
2002-01-01
Mass spectra of baryons consisting of two heavy (b or c) and one light quarks are calculated in the framework of the relativistic quark model. The light quark-heavy diquark structure of the baryon is assumed. Under this assumption the ground and excited states of both the diquark and quark-diquark bound system are considered. The quark-diquark potential is constructed. The light quark is treated completely relativistically, while the expansion in the inverse heavy quark mass is used revealing...
Amsler, C.; DeGrand, T.; Krusche, B.
2008-01-01
This biennial Review summarizes much of particle physics. Using data from previous editions, plus 2778 new measurements from 645 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and re...
Forward particle production in π-p and K-p collisions at 58 GeV/c and comparison with quark models
International Nuclear Information System (INIS)
We present single inclusive πsup(+-), π0 and Ksup(+-) spectra in the forward fragmentation region (x>0.2, psub(T)<1.5 GeV/c) as well as correlations between two charged particles. The data were recorded in an unseparated negative hadron beam at the CERN SPS using a large acceptance forward spectrometer. Our measurements are compared in detail with several models which emphasise the role of the beam valence quarks in this production process. The connection to measurements at large psub(T) is also investigated. (orig.)
Molecular and compact four-quark states
Vijande, Javier; Valcarce, A.
2009-01-01
We study charmonium ($c\\bar c n\\bar n$), bottomonium ($b\\bar b n\\bar n$) and exotic ($cc\\bar n\\bar n$ and $bb\\bar n\\bar n$) four-quark states by means of a standard non-relativistic quark potential model. We look for possible bound states. Among them we are able to distinguish between meson-meson molecules and compact four-quark states.
QQqq Four-Quark Bound States in Chiral SU(3) Quark Model
Institute of Scientific and Technical Information of China (English)
ZHANG Ming; ZHANG Hai-Xia; ZHANG Zong-Ye
2008-01-01
The possibility of QQqq heavy-light four-quark bound states has been analyzed by means of the chiral SU(3) quark model, where Q is the heavy quark (c or b) and q is the light quark (u, d, or s). We obtain a bound state for the bbnn configuration with quantum number JP=1+, I=0 and for the ccnn (JP=1+, I=0) configuration, which is not bound but slightly above the D*D* threshold (n is u or d quark). Meanwhile, we also conclude that a weakly bound state in bbnn system can also be found without considering the chiral quark interactions between the two light quarks, yet its binding energy is weaker than that with the chiral quark interactions.
Alves, Alexandre; Camargo, Daniel A.; Dias, Alex G.
2016-07-01
Motivated by a solution to the strong C P problem, we propose a model where a new heavy neutral C P -even Higgs boson couples to vectorlike quarks enhancing its production cross section whose dominant decays are into weak bosons. The masses of the vectorlike quarks are generated through interactions with a singlet scalar field charged under a broken global U (1 ) symmetry, providing a solution to the strong C P problem by means of the Peccei-Quinn mechanism. The diboson excess observed by the ATLAS Collaboration is discussed as the new heavy Higgs boson is a candidate to explain a possible signal in this channel. We also show that the 14 TeV LHC is capable of discovering this heavy Higgs with masses up to 1 TeV in the H →Z Z →ℓ+ℓ,SUP- ℓ'+ℓ'- search channel using boosted decision trees to better discriminate between signals and backgrounds and to tame systematic uncertainties in the background rates.
On quark-lepton complementarity
International Nuclear Information System (INIS)
Recent measurements of the neutrino solar mixing angle and the Cabibbo angle satisfy the empirical relation θsol + θC ≅ (π/4). This relation suggests the existence of a correlation between the mixing matrices of leptons and quarks, the so called quark-lepton complementarity. Here, we examine the possibility that this correlation originates in the strong hierarchy in the mass spectra of quarks and charged leptons, and the seesaw mechanism that gives mass to the Majorana neutrinos. In a unified treatment of quarks and leptons in which the mass matrices of all fermions have a similar Fritzsch texture, we calculate the mixing matrices VCKM and UMNSP as functions of quark and lepton masses and only two free parameters, in very good agreement with the latest experimental values on masses and mixings. Three essential ingredients to explain the quark-lepton complementarity relation are identified: the strong hierarchy in the mass spectra of quarks and charged leptons, the normal seesaw mechanism and the assumption of maximal CP violation in the lepton sector
International Nuclear Information System (INIS)
The enigmatic properties of quarks have been described by introducing for them a new SU(3) degree of freedom, which is an exact symmetry, with the additional constraint that only states scalar under this new group, named SU/sub c/(3), can be observed. This assumption implies that quarks, which transform under SU/sub c/(3) as the fundamental representation, cannot be observed alone but only in pairs q anti q (mesons) or in triplets (baryons). This new degree of freedom accounts for the symmetry in the other quantum numbers of the baryon wave function and successfully explains (π0 → 2 γ) or reduces (R value) previous discrepancies. The purpose of this work is to show that the octonion algebra supplies a natural framework both for the SU(3) character of the new degree of freedom and for the nonobservability of nonsinglet states
A New Model for Quark Mass Matrix
Institute of Scientific and Technical Information of China (English)
JIANG Zhi-Wei
2011-01-01
We study the status of S3, I.e. A slightly broken symmetry of quarks and propose a new model in which the S3 symmetry among the three generation up-quarks is slightly broken into the C2 symmetry while the S3 symmetry of the down-quarks is completely broken in a different way.%@@ We study the status of Sa, i.e.a slightly broken symmetry of quarks and propose a new model in which the Sa symmetry among the three generation up-quarks is slightly broken into the C symmetry while the S symmetry of the down-quarks is completely broken in a different way.
Radial Correlations between two quarks
Green, A M; Pennanen, P; Michael, C
2001-01-01
In nuclear many-body problems the short-range correlation between two nucleons is well described by the corresponding correlation in the {two}-body problem. Therefore, as a first step in any attempt at an analogous description of many-quark systems, it is necessary to know the two-quark correlation. With this in mind, we study the light quark distribution in a heavy-light meson with a static heavy quark. The charge and matter radial distributions of these heavy-light mesons are measured on a lattice with a light quark mass about that of the strange quark. Both distributions can be well fitted upto r approx 0.7 fm with the exponential form w_i^2(r), where w_i(r)=A exp(-r/r_i). For the charge(c) and matter(m) distributions r_c approx 0.32(2) fm and r_m \\approx 0.24(2) fm. We also discuss the normalisation of the total charge (defined to be unity in the continuum limit) and matter integrated over all space, finding 1.30(5) and 0.4(1) respectively for a lattice spacing approx 0.17 fm.
Top quark mass measurements at CDF
Energy Technology Data Exchange (ETDEWEB)
Maki, Tuula; /Helsinki U. /Helsinki Inst. of Phys.
2007-10-01
The top quark mass is interesting both as a fundamental parameter of the standard model as well as an important input to precision electroweak tests. The CDF Collaboration has measured the top quark mass with high precision in all decay channels with complementary methods. A combination of the results from CDF gives a top quark mass of 170.5{+-}1.3(stat.){+-}1.8(syst.) GeV/c{sup 2}.
Production and decay of heavy top quarks
International Nuclear Information System (INIS)
Experimental evidence indicates that the top quark exists and has a mass between 50 and 200 GeV/c2. The decays of a top quark with a mass in this range are studied with emphasis placed on the mass region near the threshold for production of real W bosons. Topics discussed are: (1) possible enhancement of strange quark production when MW + ms t W + mb; (2) exclusive decays of T mesons to B and B* mesons using the non-relativistic quark model; (3) polarization of intermediate W's in top quark decay as a source of information on the top quark mass. The production of heavy top quarks in an e+e- collider with a center-of-mass energy of 2 TeV is studied. The effective-boson approximation for photons, Z0's and W's is reviewed and an analogous approximation for interfaces between photons and Z0's is developed. The cross sections for top quark pair production from photon-photon, photon-Z0, Z0Z0, and W+W- fusion are calculated using the effective-boson approximation. Production of top quarks along with anti-bottom quarks via γW+ and Z0W+ fusion is studied. An exact calculation of γe+ → bar νt bar b is made and compared with the effective-W approximation. 31 refs., 46 figs
Thermodynamics of Constituent Quarks
Pirner, H. J.; Wachs, M
1997-01-01
We investigate the thermal behavior of quarks and antiquarks interacting via a temperature-dependent linear potential. The quarks are constituent quarks with dynamically generated masses from the background linear $\\sigma$-model.We find a transition from a system of bound mesons to a correlated quark gas at the same temperature as the chiral transition temperature.
Heavy quark spectroscopy and decay
International Nuclear Information System (INIS)
The understanding of q anti q systems containing heavy, charmed, and bottom quarks has progressed rapidly in recent years, through steady improvements in experimental techniques for production and detection of their decays. These lectures are meant to be an experimentalist's review of the subject. In the first of two lectures, the existing data on the spectroscopy of the bound c anti c and b anti b systems will be discussed. Emphasis is placed on comparisons with the theoretical models. The second lecture covers the rapidly changing subject of the decays of heavy mesons (c anti q and b anti q), and their excited states. In combination, the spectroscopy and decays of heavy quarks are shown to provide interesting insights into both the strong and electroweak interactions of the heavy quarks. 103 refs., 39 figs
International Nuclear Information System (INIS)
The quark-gluon plasma (QGP) is a state of matter in which the universe was expected to be a few micro-seconds after the big-bang. Violent collisions of heavy ions are supposed to re-create this state in particle accelerators. Numerous signatures of this fugacious state have already been observed at the RHIC (relativistic heavy ion collider). The first evidence of the violence of collisions is the number of generated particles: about 6000 per collision, mostly hadrons. This figure seems high but in fact is less than theoretically expected and is the first sign of the formation of a QGP that saturates the density of gluons. Another sign, observed at the RHIC is the damping of the particle jets that are produced in the collision. This damping is consistent with the crossing of a medium whose density is so high that it can not be made of hadrons but of partons. In the RHIC experiments the collective behaviour of quarks and gluons shows that they are strongly interacting with one another. This fact supports the idea that the QGP is more a perfect liquid rather than an ideal gas in which quarks and gluons move freely. (A.C.)
Multibody quark forces in quantum chromodynamics
International Nuclear Information System (INIS)
A general exposition of multibody quark forces in quantum chromodynamics is given. The low-energy Hamiltonian involves two-, three-, and four-body quark potentials. We compute the short-range three- and four-body potentials to lowest-order terms in v/c and show that the former does not contribute to the mass of baryons
On the strange quark mass with improved staggered quarks
Hein, J.; Davies, C; Lepage, G. P.; Mason, Q.; Trottier, H.
2002-01-01
We present results on the sum of the masses of light and strange quark using improved staggered quarks. Our calculation uses 2+1 flavours of dynamical quarks. The effects of the dynamical quarks are clearly visible.
Fitting Precision Electroweak Data with Exotic Heavy Quarks
Chang, Darwin; Chang, We-Fu; Ma, Ernest
1999-01-01
The 1999 precision electroweak data from LEP and SLC persist in showing some slight discrepancies from the assumed standard model, mostly regarding $b$ and $c$ quarks. We show how their mixing with exotic heavy quarks could result in a more consistent fit of all the data, including two unconventional interpretations of the top quark.
Understanding penta quark with various quark models
Ping, J; Wang, F; Goldman, T; Ping, Jialun; Qing, Di; Wang, Fan
2004-01-01
The pentaquark state recently discovered has been studied with three quark models which either fit the nucleon spin structure or the $NN$ scattering. A minimum $\\Theta^+$ mass of 1620 MeV is obtained both for the ${1/2}^\\pm$ state. The mixing of various color structure configurations, which would reduce the mass of the penta-quark state, should be taking into account in the calculation of penta-quark mass.
Indian Academy of Sciences (India)
Yuji Takeuchi
2012-10-01
Since the top quark was discovered at Tevatron in 1995, many top quark properties have been measured. However, the top quark is still interesting due to unique features which originate from the extremely heavy mass, and providing various test grounds on the Standard Model as well as searches for a new physics. Though the measurements of the top quark had been performed only at Tevatron so far, LHC is now ready for measurements with more top quarks than Tevatron. In this article, recent measurements of top quark properties from Tevatron (CDF and DØ) as well as LHC (ATLAS and CMS) are presented.
Thermalization of Quark Matter Produced at the Highest Energy of a Relativistic Heavy-Ion Collider
Institute of Scientific and Technical Information of China (English)
XU Xiao-Ming
2005-01-01
@@ Thermalization of quark matter is studied via a transport equation, which includes triple-quark elastic scattering amplitudes calculated in perturbative QCD. The triple-quark scatterings are demonstrated to be important for an anisotropic initial quark distribution produced in central Au-Au collisions at √sNN = 200 GeV. By examining momentum isotropy to which the transport equation leads, we can determine a thermalization time of 2.2fm/c for quark matter itself to thermalize by the two-quark and the triple-quark elastic scatterings. Meanwhile, an initial thermal quark distribution function is obtained.
HARD QUARK-QUARK SCATTERING WITH EXCLUSIVE REACTIONS*
Barton, D; Bunce, G.; Carroll, A.; Makdisi, Y.; Baller, B.; Blazey, G.; Courant, H.; Heller, K; Heppelmann, S.; Marshak, M.; Peterson, E.; Shupe, M.; Wahl, D.; Gushue, S.; Russell, J.
1985-01-01
We present data from π-p → elastic and ρ-p final states for scattering at 90° center of mass, -t = 9 GeV2/c2. A large ρ-p signal is seen and the ρ- are strongly polarized. This polarization tests a QCD prediction that quarks cannot flip helicity. The test fails dramatically.
International Nuclear Information System (INIS)
The D OE collaboration reports on a search for the Standard Model top quark in p bar p collisions at √s = 1.8 TeV at the Fermilab Tevatron, with an integrated luminosity of approximately 50 pb-1. We have searched for t bar t production in the dilepton and single-lepton decay channels, with and without tagging of b quark jets. We observe 17 events with an expected background of 3.8 ± 0.6 events. The probability for an upward fluctuation of the background to produce the observed signal is 2 x 10-6 (equivalent to 4.6 standard deviations). The kinematic properties of the excess events are consistent with top quark decay. We conclude that we have observed the top quark and measure its mass to be 199-21+19 (stat.) ±22 (syst.) GeV/c21 and its production cross section to be 6.4 ± 2.2 pb. Other decay channels are under study such as the t bar t to all-jets channel which might yield additional information about the top quark
Tevatron combined top quark mass
International Nuclear Information System (INIS)
We summarize the top-quark mass measurements from the CDF and D0 experiments at Fermilab. We combine published Run I (1992-1996) measurements with the most precise published and preliminary Run II (2001-2012) measurements using a data set corresponding to up to 8.7 fb-1 of pp-bar collisions. Taking uncertainty correlations into account, and adding in quadrature the statistical and systematic uncertainties, the resulting preliminary Tevatron average mass of the top quark is mt = 173.20 ± 0.87 GeV/c2. (authors)
Zhou, A Z; Wu, X J; Wang, N; Hong, X Y
2004-01-01
A starquake mechanism for pulsar glitches is developed in the solid quark star model. It is found that the general glitch natures (i.e., the glitch amplitudes and the time intervals) could be reproduced if solid quark matter, with high baryon density but low temperature, has properties of shear modulus \\mu = 10^{30~34} erg/cm^3 and critical stress \\sigma_c = 10^{18~24} erg/cm^3. The post-glitch behavior may represent a kind of damped oscillations.
Institute of Scientific and Technical Information of China (English)
ZONG Hong-Shi; WU Xiao-Hua; SUN Wei-Min; ZHAO En-Guang; WANG Fan
2003-01-01
A method for obtaining the smallcurrent quark mass dependence of the dressed quark propagator froman effective quark-quark interaction model is developed. Within this approach the small current quark mass effects ondressed-quark propagator have been studied. A comparison with previous results is given.
Symmetries and aggregates of quarks as constituents of hadrons
International Nuclear Information System (INIS)
The interest of the Lie algebra of the group SU(n) for the classification of hadrons and the description of some of their static properties is emphasized for n=3, 4, 6, 8. The cases n=3 and 4 allow to introduce the quark flavors (u,d,s,) and (u,d,c,s), respectively, and the consideration of the spin of hadrons leads to the chain SU(2m) contains SU(m) x SU(2). The hadrons are described as bound states or aggregates of quarks of type quark-quark-quark for baryons and quark-antiquark for mesons. The Pauli exclusion principle applied to the three-quark baryons requires the introduction of a new quantum number, the color: each flavor of quark then comes in three colors
Photoproduction of Heavy Quarks
Krämer, Michael
1995-01-01
Heavy quarks are copiously produced in two-photon collisions at $e^+e^-$ colliders. The theoretical predictions including QCD radiative corrections are compared to recent experimental data on $\\gamma\\gamma$ production of charm quarks at PETRA, PEP, TRISTAN and LEP. Photoproduction of heavy quarks at HERA is an important tool to measure the gluon distribution in the proton. New theoretical results on heavy quark photoproduction at large transverse momenta are discussed and NLO predictions for ...
Renormalized quark-anti-quark free energy
Zantow, F.; Kaczmarek, O.; Karsch, F.; Petreczky, P.
2003-01-01
We present results on the renormalized quark-anti-quark free energy in SU(3) gauge theory at finite temperatures. We discuss results for the singlet, octet and colour averaged free energies and comment on thermal relations which allow to extract separately the potential energy and entropy from the free energy.
ATLAS collaboration; LHCb collaboration
2016-01-01
Measurements of top quarks from Run-I and Run-II of the LHC are presented. Results on differential and inclusive top quark production cross sections, measured by the ATLAS, CMS and LHCb experiments, and measurements of top quark properties and mass are reported.
Xu, R. X.
2004-01-01
The quark matter may have great implications in astrophysical studies, which could appear in the early Universe, in compact stars, and/or as cosmic rays. After a general review of astrophysical quark matter, the density-dominated quark matter is focused.
Phenomenology of quark-lepton symmetric models
International Nuclear Information System (INIS)
Quark-lepton symmetric models are a new class of gauge theories which unify the quarks and leptons. In these models the gauge group of the standard model is extended to include a color group for the leptons, and consequently the quarks and leptons can then be related by a Z2 discrete quark-lepton symmetry. Phenomenological implications of these theories are explored. Two varieties are analysed: one being the simplest quark-lepton symmetric model, and the other containing conventional left-right symmetry. Each theory has a Z' boson, whose masses are constrained at 90% C.L. to be greater than 700 GeV and 650 GeV respectively. Phenomenological constraints from rare decays and the implications of the extended fermion spectrum are also examined. 37 refs., 2 tabs
Quark Orbital Angular Momentum
Burkardt, Matthias
2016-06-01
Generalized parton distributions provide information on the distribution of quarks in impact parameter space. For transversely polarized nucleons, these impact parameter distributions are transversely distorted and this deviation from axial symmetry leads on average to a net transverse force from the spectators on the active quark in a DIS experiment. This force when acting along the whole trajectory of the active quark leads to transverse single-spin asymmetries. For a longitudinally polarized nucleon target, the transverse force implies a torque acting on the quark orbital angular momentum (OAM). The resulting change in OAM as the quark leaves the target equals the difference between the Jaffe-Manohar and Ji OAMs.
International Nuclear Information System (INIS)
The quark model began as little more than a quantum-number counting device. After a brief period during which quarks only played a symmetry role, serious interest in quark dynamics developed. The marriage of the principle of local gauge invariance and quarks has been astonishingly productive. Although many questions still need to be be answered, there is little doubt that the strong, weak and electroweak interactions of matter are described by gauge theories of interactions of the quarks. This review is focussed on the successes
Quark Orbital Angular Momentum
Burkardt, Matthias
2016-03-01
Generalized parton distributions provide information on the distribution of quarks in impact parameter space. For transversely polarized nucleons, these impact parameter distributions are transversely distorted and this deviation from axial symmetry leads on average to a net transverse force from the spectators on the active quark in a DIS experiment. This force when acting along the whole trajectory of the active quark leads to transverse single-spin asymmetries. For a longitudinally polarized nucleon target, the transverse force implies a torque acting on the quark orbital angular momentum (OAM). The resulting change in OAM as the quark leaves the target equals the difference between the Jaffe-Manohar and Ji OAMs.
Foot, R; Volkas, R R
1992-01-01
Quark-lepton symmetric models are a class of gauge theories motivated by the similarities between the quarks and leptons. In these models the gauge group of the standard model is extended to include a ``color'' group for the leptons. Consequently, the quarks and leptons can then be related by a $Z_2$ discrete quark-lepton symmetry which is spontaneously broken by the vacuum. Models utilizing quark-lepton symmetry with acceptable and interesting collider phenomenology have been constructed. The cosmological consequences of these models are also discussed.
Lavelle, Martin; McMullan, David
1995-01-01
It is shown that colour can only be defined on gauge invariant states. Since the ability to associate colour with constituent quarks is an integral part of the constituent quark model, this means that, if we want to extract constituent quarks from QCD, we need to dress Lagrangian quarks with gluons so that the result is gauge invariant. We further prove that gauge fixings can be used to construct such dressings. Gauge invariant dressed quark states are presented and a direct approach to the i...
Carinhas, P A
1993-01-01
Typical nuclear equations of state and a quark bag model, surprisingly, allow compact stars with alternate layers of neutrons and quarks. One can determine on the basis of the Gibbs free energy which phase, nuclear or quark, is energetically favorable. Using the nuclear equation of state of Wiringa, and a quark equation of state given by Freedman and McLerran, the allowed quark parameter space for such layer stars is searched. This paper differs from past work in that configurations are found in which quark matter is located exterior and interior to shells of nuclear matter, i.e., dependent on quark parameters, a star may contain several alternating layers of quark and nuclear matter. Given the uncertainty in the quark parameter space, one can estimate the probability for finding pure neutron stars, pure quark stars (strange stars), stars with a quark core and a nucleon exterior, or layer stars. Several layer models are presented. The physical characteristics, stability, and results of a thorough search of th...
Kim, S. B.
1995-08-01
Top quark production is observed in{bar p}p collisions at{radical}s= 1.8 TeV at the Fermilab Tevatron. The Collider Detector at Fermilab (CDF) and D{O} observe signals consistent with t{bar t} to WWb{bar b}, but inconsistent with the background prediction by 4.8{sigma} (CDF), 4.6a (D{O}). Additional evidence for the top quark Is provided by a peak in the reconstructed mass distribution. The kinematic properties of the excess events are consistent with the top quark decay. They measure the top quark mass to be 176{plus_minus}8(stat.){plus_minus}10(sys.) GeV/c{sup 2} (CDF), 199{sub -21}{sup+19}(stat.){plus_minus}22(sys.) GeV/c{sup 2} (D{O}), and the t{bar t} production cross section to be 6.8{sub -2.4}{sup+3.6}pb (CDF), 6.4{plus_minus}2.2 pb (D{O}).
Quark Number Susceptibility with Finite Quark Mass in Holographic QCD
Kim, Kyung-il; Kim, Youngman; Takeuchi, Shingo; Tsukioka, Takuya
2010-01-01
We study the effect of a finite quark mass on the quark number susceptibility in the framework of holographic QCD. We work in a bottom-up model with a deformed AdS black hole and D3/D7 model to calculate the quark number susceptibility at finite temperature with/without a finite quark chemical potential. As expected the finite quark mass suppresses the quark number susceptibility. We find that at high temperatures $T\\ge 600$ MeV the quark number susceptibility of light quarks and heavy quarks...
Space-Time Geometry of Quark and Strange Quark Matter
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
We study quark and strange quark matter in the context of general relativity. For this purpose, we solve Einstein's field equations for quark and strange quark matter in spherical symmetric space-times. We analyze strange quark matter for the different equations of state (EOS) in the spherical symmetric space-times, thus we are able to obtain the space-time geometries of quark and strange quark matter. Also, we discuss die features of the obtained solutions. The obtained solutions are consistent with the results of Brookhaven Laboratory, i.e. the quark-gluon plasma has a vanishing shear (i.e. quark-gluon plasma is perfect).
Energy Technology Data Exchange (ETDEWEB)
El Yakoubi, M.A
2007-03-15
The PVA4 experiment (Parity Violating in hall A4 in Mainz) aims at assessing the contribution of the strange quark to the charge and current distributions in the nucleon. In order to determine these distributions, measurements of the elastic scattering of longitudinal polarized electrons on a hydrogen target have been performed. 2 types of interaction are involved in this experiment: the electromagnetic interaction (virtual photon exchange) that dominates, and the weak interaction (neutral Z{sup 0} boson exchange). The non-conservation of the parity in the weak interaction induces an asymmetry in the counting rate according to the helicity of the electron beam. The difficulty of this experiment is that it requires the control of the systematic errors and the recording of high statistics due to the low asymmetry (about 10{sup -5} and 10{sup -6} according to the transferred momentum). This document presents the first Rosenbluth separation specific to the PVA4 at Q = 0.23 GeV/c{sup 2}. A formalism related to the violation of parity to separate the strange form factors is developed. The PVA4 experimental setup dedicated to the experiment is given, as well as the Monte-Carlo technique used to extract the strange quark contribution is detailed. The data analysis at forwards and backwards angles has enabled us to determine the following asymmetry values of parity violation: (-5.44 {+-} 0.54 (stat) {+-} 0.26 (sys)) ppm forwards and (-17.1 {+-} 1.4 (stat)) ppm backwards. The combining of these asymmetry values at Q = 0.23 GeV/c{sup 2} has led to the determination of the strange form factors G{sub E}{sup s} and G{sub M}{sup s}: G{sub E}{sup s} = (0.047 {+-} 0.041) and G{sub M}{sup s} = (-0.052 {+-} 0.164). It is also shown that while the strange quark electric component is compatible with a null value, a non-zero contribution of the magnetic part is possible.
International Nuclear Information System (INIS)
The top quark, when it was finally discovered at Fermilab in 1995 completed the three-generation structure of the Standard Model (SM) and opened up the new field of top quark physics. Viewed as just another SM quark, the top quark appears to be a rather uninteresting species. Produced predominantly, in hadron-hadron collisions, through strong interactions, it decays rapidly without forming hadrons, and almost exclusively through the single mode t -> Wb. The relevant CKM coupling Vtb is already determined by the (three-generation) unitarity of the CKM matrix. Rare decays and CP violation are unmeasurable small in the SM. Yet the top quark is distinguished by its large mass, about 35 times larger than the mass of the next heavy quark, and intriguingly close to the scale of electroweak (EW) symmetry breaking. This unique property raises a number of interesting questions. Is the top quark mass generated by the Higgs mechanism as the SM predicts and is its mass related to the top-Higgs-Yukawa coupling? Or does it play an even more fundamental role in the EW symmetry breaking mechanism? If there are new particles lighter than the top quark, does the top quark decay into them? Could non-SM physics first manifest itself in non-standard couplings of the top quark which show up as anomalies in top quark production and decays? Top quark physics tries to answer these questions. Several properties of the top quark have already been examined at the Tevatron. These include studies of the kinematical properties of top production, the measurements of the top mass, of the top production cross-section, the reconstruction of t bar t pairs in the fully hadronic final states, the study of τ decays of the top quark, the reconstruction of hadronic decays of the W boson from top decays, the search for flavor changing neutral current decays, the measurement of the W helicity in top decays, and bounds on tbar t spin correlations. Most of these measurements are limited by the small sample of
Energy Technology Data Exchange (ETDEWEB)
Ahmadov, A.; Azuelos, G.; Bauer, U.; Belyaev, A.; Berger, E. L.; Sullivan, Z.; Tait, T. M. P.
2000-03-24
The top quark, when it was finally discovered at Fermilab in 1995 completed the three-generation structure of the Standard Model (SM) and opened up the new field of top quark physics. Viewed as just another SM quark, the top quark appears to be a rather uninteresting species. Produced predominantly, in hadron-hadron collisions, through strong interactions, it decays rapidly without forming hadrons, and almost exclusively through the single mode t {r_arrow} Wb. The relevant CKM coupling V{sub tb} is already determined by the (three-generation) unitarity of the CKM matrix. Rare decays and CP violation are unmeasurable small in the SM. Yet the top quark is distinguished by its large mass, about 35 times larger than the mass of the next heavy quark, and intriguingly close to the scale of electroweak (EW) symmetry breaking. This unique property raises a number of interesting questions. Is the top quark mass generated by the Higgs mechanism as the SM predicts and is its mass related to the top-Higgs-Yukawa coupling? Or does it play an even more fundamental role in the EW symmetry breaking mechanism? If there are new particles lighter than the top quark, does the top quark decay into them? Could non-SM physics first manifest itself in non-standard couplings of the top quark which show up as anomalies in top quark production and decays? Top quark physics tries to answer these questions. Several properties of the top quark have already been examined at the Tevatron. These include studies of the kinematical properties of top production, the measurements of the top mass, of the top production cross-section, the reconstruction of t{bar t}pairs in the fully hadronic final states, the study of {tau} decays of the top quark, the reconstruction of hadronic decays of the W boson from top decays, the search for flavor changing neutral current decays, the measurement of the W helicity in top decays, and bounds on t{bar t} spin correlations. Most of these measurements are limited by
Distributions of leptons in decays of polarised heavy quarks
Czarnecki, A
2009-01-01
Analytic formulae are given for QCD corrections to the lepton spectra in decays of polarised up and down type heavy quarks. These formulae are much simpler than the published ones for the corrections to the spectra of charged leptons originating from the decays of unpolarised quarks and polarised up type quarks. Distributions of leptons in semileptonic $\\Lambda_c$ and $\\Lambda_b$ decays can be used as spin analysers for the corresponding heavy quarks. Thus our results can be applied to the decays of polarised charm and bottom quarks. For the charged leptons the corrections to the asymmetries are found to be small in charm decays whereas for bottom decays they exhibit a non-trivial dependence on the energy of the charged lepton. Short life-time enables polarisation studies for the top quark. Our results are directly applicable for processes involving polarised top quarks.
Vijande, Javier; Barnea, N.; Richard, J. M.; Valcarce, A.
2009-01-01
The physics of charm has become one of the best laboratories exposing the limitations of the naive constituent quark model and also giving hints into a more mature description of meson spectroscopy, beyond the simple quark--antiquark configurations. In this talk we review some recent studies of multiquark components in the charm sector and discuss in particular exotic and non-exotic four-quark systems, both with pairwise and many-body forces.
Testa, Massimo
1990-01-01
In the large quark mass limit, an argument which identifies the mass of the heavy-light pseudoscalar or scalar bound state with the renormalized mass of the heavy quark is given. The following equation is discussed: m(sub Q) = m(sub B), where m(sub Q) and m(sub B) are respectively the mass of the heavy quark and the mass of the pseudoscalar bound state.
Energy Technology Data Exchange (ETDEWEB)
El Yakoubi, Marouan Abdelbaste [Universite de Paris XI, Paris (France)
2007-07-01
Quantum Chromodynamics describes the proton as three valence quarks surrounded by a sea of quark-antiquark pairs and gluons.The purpose of an international program, which the PVA4 experiment takes part, is to quantify the contribution of the strange quark to the charge and current distributions in the nucleon. Experimentally, to determine these distributions measurements of elastic scattering of longitudinally polarized electrons ///on a hydrogen target are performed. Two types of interactions intervene in these experiments: the electromagnetic interaction (virtual photon exchange) which dominates, and the weak interaction (neutral boson Z{sup 0} exchange). The non-conservation of parity in the weak interaction induces an asymmetry in the counting rate according to the helicity of the electron beam. The difficulty of these experiments is that they require to control the systematic errors and to record high statistics due to the low asymmetry (about 10{sup -5} and 10{sup -6} according to the transferred momentum). This document presents the first Rosenbluth separation specific to the PVA4 at Q{sup 2} = 0.23(GeV/c){sup 2}. A formalism related to the violation of parity to separate the strange form factors is developed. The PVA4 experimental setup dedicated to the measurement is given, as well as the Monte Carlo technique used to extract the strange quark contribution is detailed. The results of the analysis are presented, and show that while the strange quark electric component is compatible with a null value, a nonzero contribution of magnetic part is possible. (author)
Dzhunushaliev, V D
1997-01-01
The spherically symmetric solution in classical SU(3) Yang - Mills theory is found. It is supposed that such solution describes a classical quark. It is regular in origin and hence the interaction between two quarks is small on the small distance. The obtained solution has the singularity on infinity. It is possible that is the reason why the free quark cannot exist. Evidently, nonlocality of this object leads to the fact that in quantum chromodynamic the difficulties arise connected with investigation of quarks interaction on large distance.
International Nuclear Information System (INIS)
We review the current status of heavy-quark symmetry and its applications to weak decays of hadrons containing a single heavy quark. After an introduction to the underlying physical ideas, we discuss in detail the formalism of the heavy-quark effective theory, including a comprehensive treatment of symmetry breaking corrections. We then illustrate some nonperturbative approaches, which aim at a dynamical, QCD-based calculation of the universal form factors of the effective theory. The main focus is on results obtained using QCD sum rules. Finally, we perform an essentially model-independent analysis of semileptonic B meson decays in the context of the heavy-quark effective theory. ((orig.))
Dakin, James T.
1974-01-01
Reviews theoretical principles underlying the quark model. Indicates that the agreement with experimental results and the understanding of the quark-quark force are two hurdles for the model to survive in the future. (CC)
New quarks: exotic versus strong
Holdom, B.
2011-01-01
The new quarks of a fourth family are being pushed into the strongly interacting regime due to the lower limits on their masses. The theoretical basis and experimental implications of such quarks are compared with exotic quarks.
Effect of temperature gradient on heavy quark anti-quark potential using gravity dual model
Ganesh, S
2016-01-01
The Quark-gluon plasma (QGP) is an expanding fireball, with finite dimensions. Given the finite dimensions, the temperature would be highest at the center, and close to the critical temperature, $T_c$, at the boundary, giving rise to a temperature gradient inside the QGP. A heavy quark anti-quark pair immersed in the QGP medium would see this temperature gradient. The effect of the temperature gradient on the quark anti-quark potential is analyzed using a gravity dual model. The resulting modification to the potential due to the temperature gradient is seen to have a $L^{-2}$ correction term. This could be a possible fallout of the breaking of conformal invariance at finite temperature.
Search for strange quark matter
Hill, J C
2000-01-01
We present results of a search for charged and neutral strangelets produced on collisions of 11.6 A GeV/c Au beams with Pt or Pb targets. Yields of light nuclei and hypernuclei produced by coalescence were measured. Penalty factors were measured for the addition to a fragment of a nucleon or strange hadron. These are useful in planning future searches for strange quark matter.
Yazgan, Efe; Collaboration, for the CMS
2014-01-01
Measurements involving top quarks provide important tests of QCD. A selected set of top quark measurements in CMS including the strong coupling constant, top quark pole mass, constraints on parton distribution functions, top quark pair differential cross sections, ttbar+0 and >0 jet events, top quark mass studied using various kinematic variables in different phase-space regions, and alternative top quark mass measurements is presented. The evolution of expected uncertainties in future LHC ru...
Top quark mass measurement in dilepton channel
International Nuclear Information System (INIS)
In this work, we measured the top quark mass in tt'-' events produced in pp'-' interactions at the center-of-mass energy 1.96 TeV using CDF detector. We used dilepton in tt'-' events where both W bosons from top quarks are decaying into leptons. The data sample corresponds to 340 pb-1. We found there 33 tt'-' candidates while expecting 10.5 ± 1.9 background events. In the measurement, we reconstruct one, representative mass for each event using the assumption about longitudinal momentum of in tt'-' system, in order to be able to kinematically solve the under-constrained system. The mass distributions (templates) are created for simulated signal and background events. Templates are parametrized in order to obtain smooth probability density functions. Likelihood maximization which includes these parametrized templates is then performed on reconstructed masses obtained from data sample in order to obtain final top quark mass estimate. The result of applying this procedure on data events is top quark mass estimate 169.5+7.7-7.2(stat.) ± 4.0(syst.) GeV/c2 for 30 out of 33 candidates, where the solution for top quark mass was found. This measurement was a part of first top quark mass measurement in dilepton channel at CDF in Run II. The top quark mass measured here is consistent with the CDF measurement in dilepton channel from Run I Mtop = 167.4 ± 10.3(stat.) ± 4.8(syst.) GeV/c2. Moreover, the combined result of four top quark mass measurements in dilepton channel from Run II (one of these four measurements is our measurement) Mtop = 167.9 ± 5.2(stat.) ± 3.7(syst.) GeV/c2 significantly (by ∼ 40%) improved the precision of top quark mass determination from Run I. It should be also noted, that this combined result is consistent with measurement obtained in 'lepton+jets' channel at CDF in Run II (Mtop = 173.5+3.9-3.8 GeV/c2). So, we don't have yet any indication about new physics beyond the Standard Model. My main contribution in this analysis was the optimization
Energy Technology Data Exchange (ETDEWEB)
Renz, Manuel; /Karlsruhe U., EKP
2008-06-01
In the first part of this diploma thesis, the current version of the KIT Flavor Separator, a neural network which is able to distinguish between tagged b-quark jets and tagged c/light-quark jets, is presented. In comparison with previous versions four new input variables are utilized and new Monte Carlo samples with a larger number of simulated events are used for the training of the neural network. It is illustrated that the output of the neural network is continuously distributed between 1 and -1, whereas b-quark jets accumulate at 1, however, c-quark jets and light-quark jets have outputs next to -1. To ensure that the network output describes observed events correctly, the shapes of all input variables are compared in simulation and data. Thus the mismodelling of any input variable is excluded. Moreover, the b jet and light jet output distributions are compared with the output of samples of observed events, which are enhanced in the particular flavor. In contrast to previous versions, no b-jet output correction function has to be calculated, because the agreement between simulation and collision data is excellent for b-quark jets. For the light-jet output, correction functions are developed. Different applications of the KIT Flavor Separator are mentioned. For example it provides a precious input to all three CDF single top quark analyses. Furthermore, it is shown that the KIT Flavor Separator is a universal tool, which can be used in every high-p{sub T} analysis that requires the identification of b-quark jets with high efficiency. As it is pointed out, a further application is the estimation of the flavor composition of a given sample of observed events. In addition a neural network, which is able to separate c-quark jets from light-quark jets, is trained. It is shown, that all three flavors can be separated in the c-net-Flavor Separator plane. As a result, the uncertainties on the estimation of the flavor composition in events with one tagged jet are cut
Non-commutative model of quark interactions
International Nuclear Information System (INIS)
A non-commutative model of quark interactions with the generalized O(2.6) symmetry in quantum phase space is considered. The model is based on the Snyder-Yang algebra, which includes in the relativistically invariant way two parameters μc and λc with dimensionality of mass and length. The equations of motion obtained in the framework of the model contain the rising potentials which provide the confinement of color particles. The values of the parameters μc and λc, as well as the masses of constituent and current quarks are estimated
QCD phase transition with chiral quarks and physical quark masses.
Bhattacharya, Tanmoy; Buchoff, Michael I; Christ, Norman H; Ding, H-T; Gupta, Rajan; Jung, Chulwoo; Karsch, F; Lin, Zhongjie; Mawhinney, R D; McGlynn, Greg; Mukherjee, Swagato; Murphy, David; Petreczky, P; Renfrew, Dwight; Schroeder, Chris; Soltz, R A; Vranas, P M; Yin, Hantao
2014-08-22
We report on the first lattice calculation of the QCD phase transition using chiral fermions with physical quark masses. This calculation uses 2+1 quark flavors, spatial volumes between (4 fm)(3) and (11 fm)(3) and temperatures between 139 and 196 MeV. Each temperature is calculated at a single lattice spacing corresponding to a temporal Euclidean extent of N(t) = 8. The disconnected chiral susceptibility, χ(disc) shows a pronounced peak whose position and height depend sensitively on the quark mass. We find no metastability near the peak and a peak height which does not change when a 5 fm spatial extent is increased to 10 fm. Each result is strong evidence that the QCD "phase transition" is not first order but a continuous crossover for m(π) = 135 MeV. The peak location determines a pseudocritical temperature T(c) = 155(1)(8) MeV, in agreement with earlier staggered fermion results. However, the peak height is 50% greater than that suggested by previous staggered results. Chiral SU(2)(L) × SU(2)(R) symmetry is fully restored above 164 MeV, but anomalous U(1)(A) symmetry breaking is nonzero above T(c) and vanishes as T is increased to 196 MeV. PMID:25192088
Rafelski, Johann
1998-01-01
We present a brief survey of the development of nuclear physics towards relativistic quark physics. This is followed by a thorough discussion of the quest for the observation of the dissolution of nuclear matter into the deconfined quark matter (QGP) in relativistic nuclear collisions. Use of strange particle signatures in search for QGP is emphasized.
Indian Academy of Sciences (India)
Eric Laenen
2012-10-01
The theoretical aspects of a number of top quark properties such as its mass and its couplings are reviewed. Essential aspects in the theoretical description of top quark production, singly, in pairs and in association, as well as its decay related to spin and angular correlations are discussed.
International Nuclear Information System (INIS)
Like any other electrically charged particles, quarks should give out electromagnetic radiation (photons) when they vibrate. One of the physics results from CERN's LEP collider is the first clear observation of this quark radiation from electron-positron collisions. At lower energies this radiation could only be inferred
Properties of bound states containing fourth family quarks
International Nuclear Information System (INIS)
The heavy fourth generation of quarks that have sufficiently small mixing with the three known SM families form hadrons. In the present work, we calculate the masses and decay constants of mesons containing either both quarks from the fourth generation or one from fourth family and the other from observed SM quarks, namely charm or bottom quark, in the framework of the QCD sum rules. In the calculations, the two gluon condensate diagrams as nonperturbative contributions are taken into account. The obtained numerical results are reduced to the known masses and decay constants of the b-bar b and c-bar c quarkonia, when the fourth family quark is replaced by the bottom or charm quark.
The hadronization time of heavy quark in nuclear matter
Song, Taesoo
2016-01-01
We study the hadronization time of heavy quark in nuclear matter by using the coalescence model and the spatial diffusion constant of heavy quark from lattice Quantum Chromodynamic calculations, assuming that the main interaction of heavy quark at the critical temperature is hadronization. It is found that the hadronization time of heavy quark is about 3 fm/c for $2\\pi T_c D_s=6$, if a heavy quark is combined with the nearest light antiquark in coordinate space without any correlation between momentum of heavy quark and that of light antiquark which form a heavy meson. However, the hadronization time reduces to 0.6-1.2 fm/c for charm and 0.4-0.9 fm/c for bottom, depending on heavy meson radius, in the presence of momentum correlation. Considering the interspace between quarks and antiquarks at the critical temperature, it seems that the hadronization of heavy quark does not happen instantaneously but gradually for a considerable time, if started from the thermal distribution of quarks and antiquarks.
String formation and chiral symmetry breaking in the heavy-light quark-antiquark system in QCD
Simonov, YA; Tjon, JA
2000-01-01
The effective quark Lagrangian is written for a light quark in the field of a static antiquark, explicitly containing field correlators as coefficient functions of products of quark operators. At large N-c the closed system of equations for the gauge-invariant quark Green's function in the field of
Light Quark Mass Effects in Bottom Quark Mass Determinations
Hoang, A. H.
2001-01-01
Recent results for charm quark mass effects in perturbative bottom quark mass determinations from $\\Upsilon$ mesons are reviewed. The connection between the behavior of light quark mass corrections and the infrared sensitivity of some bottom quark mass definitions is examined in some detail.
Light Quark Mass Effects in Bottom Quark Mass Determinations
Hoang, A H
2000-01-01
Recent results for charm quark mass effects in perturbative bottom quark mass determinations from $\\Upsilon$ mesons are reviewed. The connection between the behavior of light quark mass corrections and the infrared sensitivity of some bottom quark mass definitions is examined in some detail.
Simple-minded estimate of the masses of baryons containing single heavy quarks
Zalewska, Agnieszka; Zalewski, Kacper
1996-01-01
The masses of the yet undiscovered baryons containing single $c$ or $b$ quarks are estimated from the known masses using the following rules: equal distances in mass between the isomultiplets forming sextets, equal mass differences between the corresponding spin one-half baryons containing $c$ and $b$ quarks, hyperfine splittings inversely proportional to the masses of the heavy quarks.
Quark contribution to the proton spin in the chiral quark-meson model
Energy Technology Data Exchange (ETDEWEB)
Stern, J. (Laboratoire de Physique Theorique, Universite des Sciences et de la Technologie Houari Boumediene, Alger (DZ)); Clement, G. (Departement de Physique, Ecole Normale Spuerieure, Vieux-Kouba, Alger (DZ))
1988-12-01
It has been argued that, to leading order in the 1/N/sub c/ expansion, very little of the spin of the proton is carried by the helicities of its constituent quarks, in accordance with the results of a recent EMC experiment. The authors investigate this question by a direct computation in the chiral quark-meson model, where the proton spin is generated by cranking a mean field hedgehog baryon. For not too small values of the quark-meson coupling constant, their results are consistent with the EMC data.
AUTHOR|(CDS)2071660; Schael, Stefan; Rohlf, James W
2007-01-01
In the past thirty years particle physics has developed rapidly resulting in the formulation of the Standard Model, which seems to provide, at least in principle, a microscopic description for all known physical phenomena except gravity. The Standard Model is not complete, e.g. it lacks any explanation for the pattern of particle masses. The Higgs mechanism provides a solution to the problem of how particles acquire their masses. It implies the existence of at least one new particle, the Higgs boson H0 , which has not yet been observed. The Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN) will be switched on in winter 2007. If the Higgs boson exists, the LHC will be able to detect it. Depending on the mass of the Higgs boson, physicists have a clear idea regarding its experi- mental signature. For quite low masses (50 < mH0 < 130[ GeV]) )1 the Higgs will predominantly decay into two b-quarks. The present study describes the investigation of the identification ca- pabi...
Four-quark states in the heavy quark system
International Nuclear Information System (INIS)
Four-quark states Rsub(4q)=anti qanti qqq in a heavy quark system are considered in the framework of the potential model. A special attention is paid on the possibility of observing such states in a direct channel in e+e- annihilation. It is shown that in the system anti canti ccc there must exist a resonance with Jsup(PC)=1sup(--), spin S=2, the mass M approximately 6.75 GeV, the electron width GITAsub(esup(+)esup(-)) approximately 0.02 eV and the total width GITAsub(tot) approximately 10 MeV. For analogous state in the systems anti cantiscs and anti santi sss are obtained Msub(anti canti scs) approximately 4.8 GeV, GITAsub(esup(+)esup(-)) approximately 0.4 eV and Msub(anti santi sss) approximately 2.7 GeV, GITAsub(esup(+)esup(-)) approximately 3 eV. The decay modes of such states and possibilities of their observation are discussed. The masses of C-even 4-quark states are also calculated, their 2γ decay widths and the probabilities of charmonium and upsilonium radiative decays into these states are estimated
Multiple Parton Scattering in Nuclei: Quark-quark Scattering
Schafer, Andreas; Wang, Xin-Nian; Zhang, Ben-Wei
2007-01-01
Modifications to quark and antiquark fragmentation functions due to quark-quark (antiquark) double scattering in nuclear medium are studied systematically up to order \\cal{O}(\\alpha_{s}^2)$ in deeply inelastic scattering (DIS) off nuclear targets. At the order $\\cal{O}(\\alpha_s^2)$, twist-four contributions from quark-quark (antiquark) rescattering also exhibit the Landau-Pomeranchuck-Midgal (LPM) interference feature similar to gluon bremsstrahlung induced by multiple parton scattering. Comp...
Test of the quark statistics rules in processes of hadron multiple production
International Nuclear Information System (INIS)
The quark combinatorics rules are tested in processes of kaon production. Investigated is one of the basic suppositions of the quark combineableness: hypothesis on the fact that the processes of quark blending into hadrons do not depend on quantum numbers of the united quarks. Yields of caons in k-p- collisions at 32 GeV/c and pp-collisions at 405 GeV/c are presented
International Nuclear Information System (INIS)
We investigate the properties of multi-strange baryonic systems, comparing conventional many -- Λ hypernuclei, where the strange quarks are localized in individual hyperons, to ''strangelets'' or chunks of strange matter, which involves delocalized quarks which roam in a single large bag. Mass formulae and strong/weak decay modes for such objects are discussed, as well as the prospects for producing multi-strange systems in relativistic heavy ion collisions. For production, we consider two extremes, one based on the coalescence model and another which assumes the formation of quark-gluon-plasma. We mention the experimental searches which are underway or planned, using heavy ion beams
Beauty-quark and charm-quark pair production asymmetries at LHCb
Gauld, Rhorry; Pecjak, Ben D; Re, Emanuele
2015-01-01
The LHCb collaboration has recently performed a first measurement of the angular production asymmetry in the distribution of beauty quarks and anti-quarks at a hadron collider. We calculate the corresponding standard model prediction for this asymmetry at fixed-order in perturbation theory. Our results show good agreement with the data, which is provided differentially for three bins in the invariant mass of the $b \\bar b$ system. We also present similar predictions for both beauty-quark and charm-quark final states within the LHCb acceptance for a collision energy of $\\sqrt{s} = 13 \\, {\\rm TeV}$. We finally point out that a measurement of the ratio of the $b \\bar b$ and $c \\bar c$ cross sections may be useful for experimentally validating charm-tagging efficiencies.
Evidence for production of single top quarks
Energy Technology Data Exchange (ETDEWEB)
Abazov, V.M.; /Dubna, JINR; Abbott, B.; /Oklahoma U.; Abolins, M.; /Michigan State U.; Acharya, B.S.; /Tata Inst.; Adams, M.; /Illinois U., Chicago; Adams, T.; /Florida State U.; Aguilo, E.; /Simon Fraser U.; Ahn, S.H.; /Korea U., KODEL; Ahsan, M.; /Kansas State U.; Alexeev, G.D.; /Dubna, JINR; Alkhazov, G.; /St. Petersburg, INP /Michigan U.
2008-03-01
We present first evidence for the production of single top quarks in the D0 detector at the Fermilab Tevatron p{bar p} collider. The standard model predicts that the electroweak interaction can produce a top quark together with an antibottom quark or light quark, without the antiparticle top quark partner that is always produced from strong coupling processes. Top quarks were first observed in pair production in 1995, and since then, single top quark production has been searched for in ever larger datasets. In this analysis, we select events from a 0.9 fb{sup -1} dataset that have an electron or muon and missing transverse energy from the decay of a W boson from the top quark decay, and two, three, or four jets, with one or two of the jets identified as originating from a b hadron decay. The selected events are mostly backgrounds such as W+jets and t{bar t} events, which we separate from the expected signals using three multivariate analysis techniques: boosted decision trees, Bayesian neural networks, and matrix element calculations. A binned likelihood fit of the signal cross section plus background to the data from the combination of the results from the three analysis methods gives a cross section for single top quark production of {sigma}(p{bar p} {yields} tb + X, tqb + X) = 4.7 {+-} 1.3 pb. The probability to measure a cross section at this value or higher in the absence of signal is 0.014%, corresponding to a 3.6 standard deviation significance. The measured cross section value is compatible at the 10% level with the standard model prediction for electroweak top quark production. We use the cross section measurement to directly determine the Cabibbo-Kobayashi-Maskawa quark mixing matrix element that describes the Wtb coupling and find |V{sub tb}f{sub 1}{sup L}| = 1.31{sub -0.21}{sup +0.25}, where f{sub 1}{sup L} is a generic vector coupling. This model-independent measurement translates into 0.68 < |V{sub tb}| {le} 1 at the 95% C.L. in the standard model.
Continuum estimate of the heavy quark momentum diffusion coefficient $\\kappa$
Kaczmarek, Olaf
2014-01-01
Among quantities playing a central role in the theoretical interpretation of heavy ion collision experiments at RHIC and LHC are so-called transport coefficients. Out of those heavy quark diffusion coefficients play an important role e.g. for the analysis of the quenching of jets containing c or b quarks (D or B mesons) as observed at RHIC and LHC. We report on a lattice investigation of heavy quark momentum diffusion within pure SU(3) plasma above the deconfinement transition with the quarks...
Distributions of leptons in decays of polarised heavy quarks
Czarnecki, A; Jeżabek, M.
1994-01-01
Analytic formulae are given for QCD corrections to the lepton spectra in decays of polarised up and down type heavy quarks. These formulae are much simpler than the published ones for the corrections to the spectra of charged leptons originating from the decays of unpolarised quarks and polarised up type quarks. Distributions of leptons in semileptonic $\\Lambda_c$ and $\\Lambda_b$ decays can be used as spin analysers for the corresponding heavy quarks. Thus our results can be applied to the de...
Effect of Quark Strong Interaction in Phase Transition on Supernova Explosion
Institute of Scientific and Technical Information of China (English)
LAI Xiang-Jun; LUO Zhi-Quan; LIU Jing-Jing; LIU Hong-Lin
2008-01-01
The effect of quark interactions perturbatively to order αc on the conversion, from quark matter to strange quark matter, is studied systematically based on a recent set of current quark masses. The process has a significant effect on increasing the core temperature, the neutrino abundance and the neutrino energies even if there is no quark interaction. Furthermore, with the switch of the strong interaction among quarks, these quantities will increase respectively to some further extents with αc increase. Taking αc = 0.47 as an example, the temperature, the neutrino abundance and the total neutrino energies are further raised by about 10%, 7%, and 20% respectively, which is weakly dependent on the initial temperature. Combining the effect of the current quark mass and the effect of the quark strong interaction, the results of the conversions will greatly enhance the probability of success for a supernova explosion and deeply influence the dynamics of the supernova evolution.
Spectroscopy of heavy quark hadrons
International Nuclear Information System (INIS)
Heavy quarks play special roles in the hadron spectroscopy. Some distinct features of heavy quark dynamics and their significance in the P-wave baryons with a single heavy quark are discussed. We also explore a new color configuration in exotic tetra-quark mesons with two heavy quarks. Finally, possibility of bound states of a charmed baryon with a nucleon and nuclei are examined. (author)
Institute of Scientific and Technical Information of China (English)
ZONG Hong-Shi; PING Jia-Lun; SUN Wei-Min; CHANG Chao-Hsi; WANG Fan
2002-01-01
We exhibit a method for obtaining the low chemical potential dependence of the dressed quark propagatorfrom an effective quark-quark interaction model. Within this approach we explore the chemical potential dependenceof the dressed-quark propagator, which provides a means of determining the behavior of the chiral and deconfinementorder parameters. A comparison with the results of previous researches is given.
Xu, R
2005-01-01
Members of the family of pulsar-like stars are distinguished by their different manifestations observed, i.e., radio pulsars, accretion-driven X-ray pulsars, X-ray bursts, anomalous X-ray pulsars/soft gamma-ray repeaters, compact center objects, and dim thermal neutron stars. Though one may conventionally think that these stars are normal neutron stars, it is still an open issue whether they are actually neutron stars or quark stars, as no convincing work, either theoretical from first principles or observational, has confirmed Baade-Zwicky's original idea that supernovae produce neutron stars. After introducing briefly the history of pulsars and quark stars, the author summarizes the recent achievements in his pulsar group, including quark matter phenomenology at low temperature, starquakes of solid pulsars, low-mass quark stars, and the pulsar magnetospheric activities.
International Nuclear Information System (INIS)
Top quark studies at future e+e- colliders are considered. Two issues are discussed: a - Some results are presented on the decays of top quarks. Energy distributions of charged leptons and neutrinos in t→bW→be+ν and jets in t→bW→bdu decays are sensitive to the structure of tbW vertex. Distributions of charged leptons from top decays are particularly useful in polarization studies whereas neutrinos are sensitive to deviations from the Standard Model. b - Recent calculations are renewed on the top quark pair production in e+e- annihilation. The differential cross sections in the threshold region can lead to an accurate determination of the top quark mass and the interquark potential. The effects of the top-Higgs Yukawa coupling and some higher order QCD corrections are also under control. ((orig.))
Indian Academy of Sciences (India)
Narendra Singh
2003-01-01
Assuming a relation between the quark mass matrices of the two sectors a unique solution can be obtained for the CKM ﬂavor mixing matrix. A numerical example is worked out which is in excellent agreement with experimental data.
International Nuclear Information System (INIS)
We propose and discuss a numerical use for our previous precision results for the radiative corrections to unpolarized spin one-half baryon semileptonic decays, which is not compromised to fixing the form factors at prescribed values. We present various cross-checks and comparisons with other results available in the literature of such analytical radiative corrections. Our analysis, however, is general and applies to all charge assignments to the baryons allowed by heavy quarks. The procedure is exemplified with the processes Ξ0→Σ+eν and Λc+→Λe+ν
International Nuclear Information System (INIS)
The distribution of h1(x) of quark transverse polarization can be measured by Deep Inelastic Scattering using Collins effect as quark polarimeter. We propose to calibrate this polarimeter in e+e- → 2 jets. We give an explanation of single spin asymmetries in inclusive meson production based on the Collins effect. We propose a proportionality between the electric dipole moment of the nucleon on its tensor charge. (authors)
Quark Orbital Angular Momentum
Burkardt Matthias
2015-01-01
Definitions of orbital angular momentum based on Wigner distributions are used as a framework to discuss the connection between the Ji definition of the quark orbital angular momentum and that of Jaffe and Manohar. We find that the difference between these two definitions can be interpreted as the change in the quark orbital angular momentum as it leaves the target in a DIS experiment. The mechanism responsible for that change is similar to the mechanism that causes transverse single-spin asy...
DEFF Research Database (Denmark)
Sørensen, Paul Haase; Taylor, John C.
1984-01-01
Processes with coloured particles in the initial state are generally infrared divergent. We investigate the effect of this on processes with colourless particles in the initial state, when the amplitude is near an intermediate quark pole. The result is a characteristic logarithmic depedence on the...... 'binding energy'(even though spectator interactions are taken into account), and the result is gauge-invariant. Summed to all orders the logarithms could perhaps suppress the quark pole....
DEFF Research Database (Denmark)
Sørensen, Paul Haase; Taylor, John C.
1984-01-01
Processes with coloured particles in the initial state are generally infrared divergent. We investigate the effect of this on processes with colourless particles in the initial state, when the amplitude is near an intermediate quark pole. The result is a characteristic logarithmic depedence...... on the 'binding energy'(even though spectator interactions are taken into account), and the result is gauge-invariant. Summed to all orders the logarithms could perhaps suppress the quark pole....
The Multimedia Project Quarked!
Bean, Alice; MacDonald, Teresa
2011-01-01
Can exposure to fundamental ideas about the nature of matter help motivate children in math and science and support the development of their understanding of these ideas later? Physicists, designers, and museum educators at the University of Kansas created the Quarked!(tm) Adventures in the subatomic Universe project to provide an opportunity for youth to explore the subatomic world in a fun and user friendly way. The project components include a website (located at http://www.quarked.org) an...
Heavy Quarks in the Quark-Gluon Plasma
Rapp, Ralf
2010-01-01
Heavy-flavor particles are believed to provide valuable probes of the medium produced in ultrarelativistic collisions of heavy nuclei. In this article we review recent progress in our understanding of the interactions of charm and bottom quarks in the Quark-Gluon Plasma (QGP). For individual heavy quarks, we focus on elastic interactions for which the large quark mass enables a Brownian motion treatment. This opens a unique access to thermalization mechanisms for heavy quarks at low momentum, and thus to their transport coefficients in the quark-gluon fluid. Different approaches to evaluate heavy-quark diffusion are discussed and compared, including perturbative QCD, effective potential models utilizing input from lattice QCD and string-theoretic estimates in conformal field theories. Applications to heavy-quark observables in heavy-ion collisions are realized via relativistic Langevin simulations, where we illustrate the important role of a realistic medium evolution to quantitatively extract the heavy-quark...
Constraints on nucleon quark models from deep inelastic scattering data
International Nuclear Information System (INIS)
Within the context of Q.C.D. it is assumed that quarks and gluons have rather sharply defined masses in the confinement region. Then the experimental data on structure functions give an upper limit to the light quark masses approximately 600MeV. Target mas corrections to scaling depend on further approximations
Quark scattering of quarks and hadrons
Energy Technology Data Exchange (ETDEWEB)
Friesen, A.V.; Kalinovsky, Yu.L.; Toneev, V.D.
2014-03-01
The in-medium elastic scattering qq→qq,qq{sup ¯}→qq{sup ¯} and q{sup ¯}q{sup ¯}→q{sup ¯}q{sup ¯} is calculated within the two-flavor Polyakov-loop-extended Nambu–Jona-Lasinio model. The integral and differential quark–quark scattering, its energy and temperature dependence are considered and their flavor dependence is emphasized. The comparison with results of other approaches is presented. The consideration is implemented to the case of quark–pion scattering characterizing the interaction between quarks and hadrons in a kinetic multiphase treatment, and the first estimate of the quark–pion cross sections is given. A possible application of the obtained results to heavy ion collisions is shortly discussed.
Tung, Kwong-Kwai Humphrey
1992-01-01
The rare decays bto sX are sensitive to strong interaction corrections. The effects can be estimated by a renormalization group technique which requires the evaluation of QCD mixing among effective operators. In the dimensional reduction and the naive dimensional regularization methods, there are discrepancies in evaluating the QCD mixing of the four-quark operators with the bto sgamma and bto s+gluon dipole operators. In this thesis, the problem is investigated by considering the contributions of the epsilon -scalar field and the epsilon -dimensional operators that distinguish between the two methods. The discrepancies are shown to come from the epsilon-dimensional four-quark operators in dimensional reduction and not from the epsilon -scalar field. In the decay bto sl^+l^ -, the intermediate of cc pairs in the charm-penguin diagram can form the resonance states J/psi and psi^'. In the published literature, there is a sign discrepancy in the Breit-Wigner amplitude for the resonance effects. Here, the sign difference is settled by considering the unitarity limit of the amplitude in the Argand diagram. The effects of the resonances are quite substantial on the invariant mass spectrum for this decay. However, they are shown to be negligible on the dilepton energy spectrum below 0.95 GeV. The energy spectrum is, thus, more useful than the invariant mass spectrum for measurements of the top -quark mass. The decays Bto K^*X are well modeled by the quark-level decays bto sX. In the quark model, the hadronization is done using a nonrelativistic wave function. In the decay B to K^*gamma, the large K ^* recoil creates an uncertainty in calculating the branching ratio using the quark model. The problem is explored by considering other meson processes where data exist. The data on the pi form factor and the omegapi^0 transition form factor suggest the necessity to retain relativistic spinor and meson normalizations in the quark -model; however, the data do not resolve the
Static quark anti-quark free energy and the running coupling at finite temperature
Kaczmarek, O; Petreczky, P; Zantow, F
2004-01-01
We analyze the free energy of a static quark anti-quark pair in quenched QCD at short and large distances. From this we deduce running couplings, g^2(r,T), and determine the length scale that separates at high temperature the short distance perturbative regime from the large distance non-perturbative regime in the QCD plasma phase. Ambiguities in the definition of a coupling beyond the perturbative regime are discussed in their relation to phenomenological considerations on heavy quark bound states in the quark gluon plasma. Our analysis suggests that it is more appropriate to characterize the non-perturbative properties of the QCD plasma phase close to T_c in terms remnants of the confinement part of the QCD force rather than a strong Coulombic force.
Making quark matter at brook haven's new collider
International Nuclear Information System (INIS)
Quarks are believed to come in 6 flavours, only the lightest of which, the up and down quarks, are found in protons and neutrons. Isolated quarks have never been observed. As quarks are brought closer together, the force between them decreases dramatically, vanishing as the separation becomes very small. This suggests that quarks may become unbound if the density of quarks could be increased by squeezing a nucleus. The nucleus would have melted their constituent quarks, now free to roam the extended volume of the compressed nucleus. This situation would make a significant change in the structure of matter corresponding to a change of phase, rather like the transition from solid to liquid, but in this case from quark confined matter, to a quark gluon plasma (QGP). This new state of matter is thought to have been the natural phase of matter until 10 micro-seconds after the big-bang, and also to exist today in the core of neutron stars. Calculations show that the energy density needed to observe the phase transition is around 1 GeV/fm3, approximately 8 times that of normal nuclear matter. Attempts to recreate QGP have been underway at the relativistic heavy ion collider (RHIC) and at the CERN by colliding heavy-ion beams at the maximal energy possible. Between 4000 and 5000 charged particles are produced in the most violent events. The experimental challenge is to establish the existence of QGP from all this wealth of data. (A.C.)
Hydrodynamics of a quark droplet
Bjerrum-Bohr, Johan J; Døssing, Thomas
2011-01-01
We present a simple model of a multi-quark droplet evolution based on the hydrodynamical description. This model includes collective expansion of the droplet, effects of the vacuum pressure and surface tension. The hadron emission from the droplet is described following Weisskopf's statistical model. We have considered evolution of baryon-free droplets which have different initial temperatures and expansion rates. As a typical trend we observe an oscillating behavior of the droplet radius superimposed with a gradual shrinkage due to the hadron emission. The characteristic life time of droplets with radii 1.5-2 fm are about 9-16 fm/c.
Top quark couplings and polarization
International Nuclear Information System (INIS)
Precise measurements of top quark couplings are presented. The measurements cover the single top tW cross section, the top-quark branching-fraction ratio R=B(t → Wb)/B(t → Wq) and the CKM matrix element Vtb from the single top cross sections. Top quark polarisation in the t-channel single-top quark production and dilepton tt, and W-helicity fraction measurements along with searches of top quark anomalous couplings in lepton plus jet channel are also presented. Finally measurements of top quark pair production in association with a W or Z boson or a photon are presented
Physics with boosted top quarks
Kuutmann, Elin Bergeaas
2014-01-01
The production at the LHC of boosted top quarks (top quarks with a transverse momentum that greatly exceeds their rest mass) is a promising process to search for phenomena beyond the Standard Model. In this contribution several examples are discussed of new techniques to reconstruct and identify (tag) the collimated decay topology of the boosted hadronic decays of top quarks. Boosted top reconstruction techniques have been utilized in searches for new physical phenomena. An overview is given of searches by ATLAS, CDF and CMS for heavy new particles decaying into a top and an anti-top quark, vector-like quarks and supersymmetric partners to the top quark.
Dileptons from a Chemically Equilibrating Quark-Gluon Plasma at Finite Baryon Density
Institute of Scientific and Technical Information of China (English)
GUAN Na-Na; HE Ze-Jun; LONG Jia-Li; CAI Xiang-Zhou
2008-01-01
We perform a complete calculation for the delepton production from the processes q(q-) →l(l-), Compton-like (qg→ql(l-),(q-)g→ql(l-)), q(q-)→gl(l-), gluon fusion g(g-)→c(c-), annihilation q(q-)→c(c-) as well as multiple scattering of quarks in a chemically equilibrating quark-gluon plasma system at finite baryon density. It is found that quark-antiquark annihilation,Compton-like, gluon fusion and multiple scattering of quarks give important contribution. Moreover, the increase of the quark phase life-time with increasing initial quark chemical potential makes the dilepton yield as an increasing function of the initial quark chemical potential.
SU(6) model with heavy t-quark
International Nuclear Information System (INIS)
The representation assignments of fermions in a previous model are changed to make t-quark heavy. Together with this, the third generation (t,b,tau) as well as c-quark show some peculiar feature. For example, the left-handed component of the observed b-quark is a mixture of an SU(2) singlet with a component of a doublet, and meson (bsub(i).sup(c)dsub(i)) will decay through baryon number violating interactions of tau++psup(c). (author)
Liu, Qi; Jung, Chulwoo
2012-01-01
We present a systematic study of the effectiveness of light quark mass reweighting. This method allows a single lattice QCD ensemble, generated with a specific value of the dynamical light quark mass, to be used to determine results for other, nearby light dynamical quark masses. We study two gauge field ensembles generated with 2+1 flavors of dynamical domain wall fermions with light quark masses m_l=0.02 (m_\\pi=620 MeV) and m_l=0.01 (m_\\pi=420 MeV). We reweight each ensemble to determine results which could be computed directly from the other and check the consistency of the reweighted results with the direct results. The large difference between the 0.02 and 0.01 light quark masses suggests that this is an aggressive application of reweighting as can be seen from fluctuations in the magnitude of the reweighting factor by four orders of magnitude. Never-the-less, a comparison of the reweighed topological charge, average plaquette, residual mass, pion mass, pion decay constant, and scalar correlator between ...
Hadron production in the quark combinatorics with color quarks
International Nuclear Information System (INIS)
An effect of color quark correlations on the M:B:anti B ratio of meson, baryon and antibaryon yields in the case of multiple hadron production is considered. It is shown that when the quark baryon number reveals itself like the probability of baryon state production of the quark, the M:B:anti B ratio in the central region weakly depends on the color correlations, and it is close to the value obtained earlier without account for the color quark states
Quark-quark Double Scattering and Modified (Anti-)Quark Fragmentation Functions in Nuclei
Zhang, Ben-Wei; Wang, Xin-Nian; Schaefer, Andreas
2007-01-01
Quark-quark double scattering in eA DIS and its contribution to quark and anti-quark fragmentation functions are investigated with the generalized factorization of the relevant twist-four processes in pQCD. It is shown that the resulting modifications to quark and anti-quark fragmentation functions are different. While the numerical size of these effects cannot be determined from pQCD, the structure of our result leads to a number of qualitative predictions for the relative size of the effect...
Quark energy loss in an expanding quark-gluon plasma
Zakharov, B. G.
1998-01-01
We study the quark energy loss in an expanding quark-gluon plasma. The expanding plasma produced in high energy AA-collision is described by Bjorken's model. The dependence of the energy loss on the infrared cutoff for the radiated gluons, on the quark mass, and on the initial conditions of QCD plasma is investigated.
Studying quark condensates within models of four-quark interaction
Molodtsov, S. V.; Zinovjev, G. M.
2013-01-01
Analysing two models of four-quark interactions which are of intrinsic difference in the behaviours of their correlation lengths some issues of quark condensations are considered. It is demonstrated that the quark condensates substantially are not sensitive to the details of those interactions in the range of coupling constants interesting for applications.
Observable contributions of new exotic quarks to quark mixing
del Aguila, F.; Perez-Victoria, M.; J. Santiago
2000-01-01
Models with new vector-like quarks can produce observable quark mixing effects which are forbidden in the Standard Model. We classify all such models and write down the effective Lagrangian that results from integrating out the new quarks. We study the relations between neutral and charged currents and discuss how to distinguish among the different possibilities.
Measurement of the bottom quark lifetime
International Nuclear Information System (INIS)
The quark mixing matrix is constrained by the lifetime of the bottom quark, the off-diagonal elements involving the b quark being completely determined by the lifetime and the branching ratio between the decays b → u and b → c. If the binding of the b quark into hadrons has no effect on its decay rate, the inclusive lifetime measurement discussed here reflects precisely the quark total decay rate. Their experience with charmed hadrons serves to warn that the situation may not be so simple, and they are eager to find techniques for determining the lifetimes of individual hadron states, particularly the mesons B+, B/sub d/0 and B/sub s/0. The subject of this note, however, is a detailed evaluation of prospects for improving the inclusive measurement, as it has been performed at PEP and PETRA, based upon the impact parameter distribution of leptons from the b hadron semileptonic decays. This note supersedes intermediate reports from the Asilomar and Granlibakken meetings. The first two sections are based mainly upon studies with Monte Carlo generated quantities in which they explore the kinematics of bottom particle semileptonic decays to develop event selection criteria and measure sensitivity of the impact parameter to the lifetime and to the details of particle production. Detector effects are considered in section 3, data reduction in sections 4 and 5, and conclusions in section 6. 6 references, 11 figures, 1 table
Precision Determination of the Top Quark Mass
Energy Technology Data Exchange (ETDEWEB)
Movilla Fernandez, Pedro A.; /LBL, Berkeley
2007-05-01
The CDF and D0 collaborations have updated their measurements of the mass of the top quark using proton-antiproton collisions at {radical}s = 1.96 TeV produced at the Tevatron. The uncertainties in each of the top-antitop decay channels have been reduced. The new Tevatron average for the mass of the top quark based on about 1 fb{sup -1} of data per experiment is 170.9 {+-} 1.8 GeV/c{sup 2}.
Measurement of the Top Quark Mass
International Nuclear Information System (INIS)
We present a measurement of the top quark mass using a sample of t bar t decays into an electron or a muon, a neutrino, and four jets. The data were collected in p bar p collisions at √(s)=1.8 TeV with the Collider Detector at Fermilab and correspond to an integrated luminosity of 109 pb-1 . We measure the top quark mass to be 175.9±4.8(stat)±4.9( syst) GeV /c2 . copyright 1998 The American Physical Society
Strongly Coupled Quark Gluon Plasma (SCQGP)
Bannur, Vishnu M.
2005-01-01
We propose that the reason for the non-ideal behavior seen in lattice simulation of quark gluon plasma (QGP) and relativistic heavy ion collisions (URHICs) experiments is that the QGP near T_c and above is strongly coupled plasma (SCP), i.e., strongly coupled quark gluon plasma (SCQGP). It is remarkable that the widely used equation of state (EoS) of SCP in QED (quantum electrodynamics) very nicely fits lattice results on all QGP systems, with proper modifications to include color degrees of ...
Light-quark, heavy-quark systems
International Nuclear Information System (INIS)
There are at least three reasons for studying the physics of B and D mesons. First, the Standard Model predicts observable signal of CP violation in decays of B mesons. Second, the rates for rare decays of heavy mesons are sensitive to departures from the Standard Model. Third, precise determination of the elements of the KM matrix is naturally performed through the study of decays of heavy mesons or baryons. This discussion focuses on the heavy-quark effective theory, with discussions on symmetries and meson decay constants. Further developments in this field of study are briefly introduced. 56 refs., 3 figs
Relativistic formulation of quark model
International Nuclear Information System (INIS)
A relativistic model, which describes spin-orbital excitations of quark-antiquark bound system, is proposed. A formulation of the model provides the meson classification established in frame of the nonrelativistic quark model. 3 refs
Fedi, G.; CMS Collaboration
2016-07-01
The most recent results which concern the heavy quark hadrons done in the CMS experiment are reported. The searching area spans over the heavy quark spectroscopy, production cross sections, beauty meson decay properties, rare decays, and CP violation.
The Quark's Model and Confinement
Novozhilov, Yuri V.
1977-01-01
Quarks are elementary particles considered to be components of the proton, the neutron, and others. This article presents the quark model as a mathematical concept. Also discussed are gluons and bag models. A bibliography is included. (MA)
Richard, Jean-Marc
1994-01-01
We review the spectroscopy and some properties of hadrons containing two charmed quarks, or more generally, two heavy quarks. This includes heavy baryons such as $(bcu)$, and possible exotic multiquark states.
A Scaling Law for Quark Masses
Fritzsch, Harald; Özer, Alp Deniz
2004-01-01
We show that the observed quark masses seem to be consistent with a simple scaling law. Due to the precise values of the heavy quarks we are able to calculate the quark masses in the light quark sector. We discuss a possible value for the strange quark mass. We show that the u-type quark masses obey the scaling law very well.
Gauge-invariant approach to quark dynamics
Sazdjian, H.
2016-02-01
The main aspects of a gauge-invariant approach to the description of quark dynamics in the nonperturbative regime of quantum chromodynamics (QCD) are first reviewed. The role of the parallel transport operation in constructing gauge-invariant Green's functions is then presented, and the relevance of Wilson loops for the representation of the interaction is emphasized. Recent developments, based on the use of polygonal lines for the parallel transport operation, are presented. An integro-differential equation, obtained for the quark Green's function defined with a phase factor along a single, straight line segment, is solved exactly and analytically in the case of two-dimensional QCD in the large- N c limit. The solution displays the dynamical mass generation phenomenon for quarks, with an infinite number of branch-cut singularities that are stronger than simple poles.
Search for 4th generation quarks
Khalil, Sadia
2013-01-01
We present the results of searches for a new heavy 4th generation and vector-like quark using leptonic, and semileptonic final states comprising of electron(s) and/or muon(s) and jets. The full sample of 5 fb$^{-1}$ of pp collisions recorded with CMS experiment in 2011 at the center-of-mass energy of 7 TeV has been used. In leptonic final states, two same sign dilepton and trilepton channels have been explored. For semileptonic events, the search for heavy quarks is carried out using events with one lepton, and at least four jets with imbalance in transverse momenta, requiring at least one of the jet identified as originating from the fragmentation of a b-quark. No significant excess of events over Standard Model expectations is observed, therefore upper mass limits are set at 95\\% C.L.
Ion-induced quark-gluon implosion.
Frankfurt, L; Strikman, M
2003-07-11
We investigate nuclear fragmentation in the central proton-nucleus and nucleus-nucleus collisions at the energies of CERN LHC. Within the semiclassical approximation we argue that because of the fast increase with energy of the cross sections of soft and hard interactions each nucleon is stripped in the average process off "soft" partons and fragments into a collection of leading quarks and gluons with large p(t). Valence quarks and gluons are streaming in the opposite directions when viewed in the c.m. of the produced system. The resulting pattern of the fragmentation of the colliding nuclei leads to an implosion of the quark and gluon constituents of the nuclei. The nonequilibrium state produced at the initial stage in the nucleus fragmentation region is estimated to have densities >/=50 GeV/fm(3) at the LHC energies and probably >/=10 GeV/fm(3) at BNL RHIC. PMID:12906475
Gauge-invariant approach to quark dynamics
Sazdjian, H
2016-01-01
The main aspects of a gauge-invariant approach to the description of quark dynamics in the nonperturbative regime of QCD are first reviewed. In particular, the role of the parallel transport operation in constructing gauge-invariant Green's functions is presented, and the relevance of Wilson loops for the representation of the interaction is emphasized. Recent developments, based on the use of polygonal lines for the parallel transport operation, are then presented. An integro-differential equation is obtained for the quark Green's function defined with a phase factor along a single, straight line segment. It is solved exactly and analytically in the case of two-dimensional QCD in the large $N_c$ limit. The solution displays the dynamical mass generation phenomenon for quarks, with an infinite number of branch-cut singularities that are stronger than simple poles.
String Junction Model, Cluster Hypothesis, Penta-Quark Baryon and Tetra-Quark Meson
Imachi, Masahiro; Otsuki, Shoichiro
2007-01-01
Thirty years ago we proposed string junction model of hadrons and examined structure and reaction of hadrons including exotic ones. Since 2003 some attentions have been paid to exotic hadrons, especially to penta-quark baryon. By critically examining its theoretical analysis of Diakonov et. al, we introduce to our model "cluster hypothesis", which guarantees the classical and established picture that mass difference of hadrons among flavor multiplet members comes from that of the constituents. According to the hypothesis, the penta-quark baryon Theta^+ (S=+1) including a strange anti-quark s(bar), which is assigned to a member of 10^* representation of flavor SU(3), is heavier than non-strange members of the multiplet by Delta_s =130 ~ 150 MeV, the mass difference between the strange and non-strange quarks. In our model the mass of the penta-quark baryon is estimated as around 3 GeV. Quite recently, the Belle Collaboration has reported a candidate for tetra-quark meson, Z^+(4430 MeV). This gives us powerful c...
Indian Academy of Sciences (India)
H Weigel
2003-11-01
In this talk I review studies of hadron properties in bosonized chiral quark models for the quark ﬂavor dynamics. Mesons are constructed from Bethe–Salpeter equations and baryons emerge as chiral solitons. Such models require regularization and I show that the two-fold Pauli–Villars regularization scheme not only fully regularizes the effective action but also leads the scaling laws for structure functions. For the nucleon structure functions the present approach serves to determine the regularization prescription for structure functions whose leading moments are not given by matrix elements of local operators. Some numerical results are presented for the spin structure functions.
Quark Orbital Angular Momentum
Directory of Open Access Journals (Sweden)
Burkardt Matthias
2015-01-01
Full Text Available Definitions of orbital angular momentum based on Wigner distributions are used as a framework to discuss the connection between the Ji definition of the quark orbital angular momentum and that of Jaffe and Manohar. We find that the difference between these two definitions can be interpreted as the change in the quark orbital angular momentum as it leaves the target in a DIS experiment. The mechanism responsible for that change is similar to the mechanism that causes transverse single-spin asymmetries in semi-inclusive deep-inelastic scattering.
International Nuclear Information System (INIS)
This set of lectures deals with the transition from nuclear matter to quark matter. The reader will learn not only about the theory of quark- gluon plasmas but also how they are obtained in the laboratory through heavy-ion collisions or where they can be found in astrophysical objects such as compact stars. The book fills a gap between well-known textbook material and the research literature and is thus perfectly suited for postgraduate students who wish to enter this field, for lecturers looking for advanced material for their courses and for scientists in search of a modern source of reference on these topics
Smith, Martin C.; Willenbrock, Scott S.
1996-01-01
The top quark decays more quickly than the strong-interaction time scale, $\\lqcd^{-1}$, and might be expected to escape the effects of nonperturbative QCD. Nevertheless, the top-quark pole mass, like the mass of a stable heavy quark, is ambiguous by an amount proportional to $\\lqcd$.
Holographic Penta and Hepta Quark State in Confining Gauge Theories
Ghoroku, Kazuo; Taminato, Tomoki; Toyoda, Fumihiko
2010-01-01
We study a new embedding solutions of D5 brane in an asymptotic AdS${}_5\\times S^5$ space-time, which is dual to a confining $SU(N_c)$ gauge theory. The D5 brane is wrapped on $S^5$ as in the case of the vertex of holographic baryon. However, the solution given here is different from the usual baryon vertex in the point that it couples to $k$-anti-quarks and $N_c+k$ quarks on the opposite two points of $S^5$, the north and south poles, respectively. The total quark number of this state is preserved as $N_c$ when minus one is assigned to anti-quark, then it forms a color singlet like the baryon. However, this includes anti-quarks and quarks, whose number is larger than that of the baryon. When we set as $N_c=3$, we find the so called penta and hepta-quark states. We study the dynamical properties of these states by solving the vertex and string configurations for such states. The mass spectra of these states and the tension of the stretched vertex are estimated, and they are compared with that of the baryon.
Determination of the width of the top quark
Abazov, V M; Abolins, M; Acharya, B S; Adams, M; Adams, T; Alexeev, G D; Alkhazov, G; Altona, A; Alverson, G; Alves, G A; Ancu, L S; Aoki, M; Arnoud, Y; Arov, M; Askew, A; \\degAsman, B; Atramentov, O; Avila, C; BackusMayes, J; Badaud, F; Bagby, L; Baldin, B; Bandurin, D V; Banerjee, S; Barberis, E; Baringer, P; Barreto, J; Bartlett, J F; Bassler, U; Bazterra, V; Beale, S; Bean, A; Begalli, M; Begel, M; Belanger-Champagne, C; Bellantoni, L; Beri, S B; Bernardi, G; Bernhard, R; Bertram, I; Besan?con, M; Beuselinck, R; Bezzubov, V A; Bhat, P C; Bhatnagar, V; Blazey, G; Blessing, S; Bloom, K; Boehnlein, A; Boline, D; Bolton, T A; Boos, E E; Borissov, G; Bose, T; Brandt, A; Brandt, O; Brock, R; Brooijmans, G; Bross, A; Brown, D; Brown, J; Bu, X B; Buchholz, D; Buehler, M; Buescher, V; Bunichev, V; Burdinb, S; Burnett, T H; Buszello, C P; Calpas, B; Camacho-P?erez, E; Carrasco-Lizarraga, M A; Casey, B C K; Castilla-Valdez, H; Chakrabarti, S; Chakraborty, D; Chan, K M; Chandra, A; Chen, G; Chevalier-Th?ery, S; Cho, D K; Cho, S W; Choi, S; Choudhary, B; Christoudias, T; Cihangir, S; Claes, D; Clutter, J; Cooke, M; Cooper, W E; Corcoran, M; Couderc, F; Cousinou, M -C; Croc, A; Cutts, D; ?Cwiok, M; Das, A; Davies, G; De, K; de Jong, S J; De La Cruz-Burelo, E; D?eliot, F; Demarteau, M; Demina, 47 R; Denisov, D; Denisov, S P; Desai, S; DeVaughan, K; Diehl, H T; Diesburg, M; Dominguez, A; Dorland, T; Dubey, A; Dudko, L V; Duggan, D; Duperrin, A; Dutt, S; Dyshkant, A; Eads, M; Edmunds, D; Ellison, J; Elvira, V D; Enari, Y; Eno, S; Evans, H; Evdokimov, A; Evdokimov, V N; Facini, G; Ferbel, T; Fiedler, F; Filthaut, F; Fisher, W; Fisk, H E; Fortner, M; Fox, H; Fuess, S; Gadfort, T; Garcia-Bellido, A; Gavrilov, V; Gay, P; Geist, W; Geng, W; Gerbaudo, D; Gerber, C E; Gershtein, Y; Ginther, G; Golovanov, G; Goussiou, A; Grannis, P D; Greder, S; Greenlee, H; Greenwood, Z D; Gregores, E M; Grenier, G; Gris, Ph; Grivaz, J -F; Grohsjean, A; Gr?unendahl, S; Gr?unewald, M W; Guo, F; Guo, J; Gutierrez, G; Gutierrez, P; Haasc, A; Hagopian, S; Haley, J; Han, L; Harder, K; Harel, A; Hauptman, J M; Hays, J; Head, T; Hebbeker, T; Hedin, D; Hegab, H; Heinson, A P; Heintz, U; Hensel, C; La Cruz, I Heredia-De; Herner, K; Hesketh, G; Hildreth, M D; Hirosky, R; Hoang, T; Hobbs, J D; Hoeneisen, B; Hohlfeld, M; Hossain, S; Hubacek, Z; Huske, N; Hynek, V; Iashvili, I; Illingworth, R; Ito, A S; Jabeen, S; Jaffr?e, M; Jain, S; Jamin, D; Jesik, R; Johns, K; Johnson, M; Johnston, D; Jonckheere, A; Jonsson, P; Joshi, J; Justed, A; Kaadze, K; Kajfasz, E; Karmanov, D; Kasper, P A; Katsanos, I; Kehoe, R; Kermiche, S; Khalatyan, N; Khanov, A; Kharchilava, A; Kharzheev, Y N; Khatidze, D; Kirby, M H; Kohli, J M; Kozelov, A V; Kraus, J; Kumar, A; Kupco, A; Kur?ca, T; Kuzmin, V A; Kvita, J; Lammers, S; Landsberg, G; Lebrun, P; Lee, H S; Lee, S W; Lee, W M; Lellouch, J; Li, L; Li, Q Z; Lietti, S M; Lim, J K; Lincoln, D; Linnemann, J; Lipaev, V V; Lipton, R; Liu, Y; Liu, Z; Lobodenko, A; Lokajicek, M; Love, P; Lubatti, H J; Luna-Garciae, R; Lyon, A L; Maciel, A K A; Mackin, D; Madar, R; Maga?na-Villalba, R; Malik, S; Malyshev, V L; Maravin, Y; Mart?\\inez-Ortega, J; McCarthy, R; McGivern, C L; Meijer, M M; Melnitchouk, A; Menezes, D; Mercadante, P G; Merkin, M; Meyer, A; Meyer, J; Mondal, N K; Muanza, G S; Mulhearn, M; Nagy, E; Naimuddin, M; Narain, M; Nayyar, R; Neal, H A; Negret, J P; Neustroev, P; Novaes, S F; Nunnemann, T; Obrant, G; Orduna, J; Osman, N; Osta, J; Garz?on, G J Otero y; Owen, 1 M; Padilla, M; Pangilinan, M; Parashar, N; Parihar, V; Park, S K; Parsons, J; Partridgec, R; Parua, N; Patwa, A; Penning, B; Perfilov, M; Peters, K; Peters, Y; Petrillo, G; P?etroff, P; Piegaia, R; Piper, J; Pleier, M -A; Podesta-Lermaf, P L M; Podstavkov, V M; Pol, M -E; Polozov, P; Popov, A V; Prewitt, M; Price, D; Protopopescu, S; Qian, J; Quadt, A; Quinn, B; Rangel, M S; Ranjan, K; Ratoff, P N; Razumov, I; Renkel, P; Rich, P; Rijssenbeek, M; Ripp-Baudot, I; Rizatdinova, F; Rominsky, M; Royon, C; Rubinov, P; Ruchti, R; Safronov, G; Sajot, G; S?anchez-Hern?andez, A; Sanders, M P; Sanghi, B; Santos, A S; Savage, G; Sawyer, L; Scanlon, T; Schamberger, R D; Scheglov, Y; Schellman, H; Schliephake, T; Schlobohm, S; Schwanenberger, C; Schwienhorst, R; Sekaric, J; Severini, H; Shabalina, E; Shary, V; Shchukin, A A; Shivpuri, R K; Simak, V; Sirotenko, V; Skubic, P; Slattery, P; Smirnov, D; Smith, K J; Snow, G R; Snow, J; Snyder, S; S?oldner-Rembold, S; Sonnenschein, L; Sopczak, A; Sosebee, M; Soustruznik, K; Spurlock, B; Stark, J; Stolin, V; Stoyanova, D A; Strauss, E; Strauss, M; Strom, D; Stutte, L; Svoisky, P; Takahashi, M; Tanasijczuk, A; Taylor, W; Titov, M; Tokmenin, V V; Tsybychev, D; Tuchming, B; Tully, C; Tuts, P M; Uvarov, L; Uzunyan, S Uvarov S; Van Kooten, R; van Leeuwen, W M; Varelas, N; Varnes, E W; Vasilyev, I A; Verdier, P; Vertogradov, L S; Verzocchi, M; Vesterinen, M; Vilanova, D; Vint, P; Vokac, P; Wahl, H D; Wang, M H L S; Warchol, J; Watts, G; Wayne, M; Weberg, M; Welty-Rieger, L; Wetstein, M; White, A; Williams, D Wicke M R J; Wilson, G W; Wimpenny, S J; Wobisch, M; Wood, D R; Wyatt, T R; Xie, Y; Xu, C; Yacoob, S; Yamada, R; Yang, W -C; Yasuda, T; Yatsunenko, Y A; Ye, Z; Yin, H; Yip, K; Yoo, H D; Youn, S W; Yu, J; Zelitch, S; Zhao, T; Zhou, B; Zhu, J; Zielinski, M; Zieminska, D; Zivkovic, L
2010-01-01
We extract the total width of the top quark, Gamma_t, from the partial decay width Gamma(t -> W b) measured using the t-channel cross section for single top quark production and from the branching fraction B(t -> W b) measured in ttbar events using up to 2.3 fb^-1 of integrated luminosity collected by the D0 Collaboration at the Tevatron ppbar Collider. The result is Gamma_t = 1.99 +0.69 -0.55 GeV, which translates to a top-quark lifetime of tau_t = (3.3 +1.3 -0.9) x 10^-25 s. Assuming a high mass fourth generation b' quark and unitarity of the four-generation quark-mixing matrix, we set the first upper limit on |Vtb'| < 0.63 at 95% C.L.
Continuum estimate of the heavy quark momentum diffusion coefficient $\\kappa$
Kaczmarek, Olaf
2014-01-01
Among quantities playing a central role in the theoretical interpretation of heavy ion collision experiments at RHIC and LHC are so-called transport coefficients. Out of those heavy quark diffusion coefficients play an important role e.g. for the analysis of the quenching of jets containing c or b quarks (D or B mesons) as observed at RHIC and LHC. We report on a lattice investigation of heavy quark momentum diffusion within pure SU(3) plasma above the deconfinement transition with the quarks treated to leading order in the heavy mass expansion. We measure the relevant colour-electric Euclidean correlator and based on several lattice spacings perform the continuum extrapolation. This extends our previous studies progressing towards a removal of lattice artifacts and a physical interpretation of the results. We find that the correlation function clearly exceeds its perturbative counterpart which suggests that at temperatures just above the critical one, non-perturbative interactions felt by the heavy quarks ar...
Helicity-dependent generalized parton distributions and composite constituent quarks
Scopetta, S; Scopetta, Sergio; Vento, Vicente
2004-01-01
An approach recently proposed to calculate the nucleon generalized parton distributions (GPDs) in a constituent quark model (CQM) scenario, considering the constituent quarks as complex systems, is used here to obtain helicity-dependent GPDs. They are obtained from the wave functions of the non relativistic CQM of Isgur and Karl, convoluted with the helicity-dependent GPDs of the constituent quarks themselves. The latter are modelled by using the polarized structure functions of the constituent quark, the double distribution representation of GPDs, and a recently proposed phenomenological constituent quark form factor. The present approach permits to access a kinematical range corresponding to both the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi and the Efremov-Radyushkin-Brodsky-Lepage regions, for small values of the momentum transfer and of the skewedness parameter. In this kinematical region, the present calculation represents a prerequisite for the evaluation of cross sections relevant to deeply virtual C...
Indian Academy of Sciences (India)
C P Singh
2000-04-01
Recent trends in the research of quark gluon plasma (QGP) are surveyed and the current experimental and theoretical status regarding the properties and signals of QGP is reported. We hope that the experiments commencing at relativistic heavy-ion collider (RHIC) in 2000 will provide a glimpse of the QGP formation.
International Nuclear Information System (INIS)
New experimental and theoretical developments in heavy quark spectroscopy are reviewed. From studies of J/psi decays, the eta' is found to have some ''glue'' or other inert component, while the iota (a glueball candidate) probably contains some quarks as well. The xi(2.2) persists in new Mark III data, but is not seen by the DM2 collaboration. The production of charmonium states by anti pp reactions is reviewed. First evidence for a P- wave charmed meson, D(2420), has been presented by the ARGUS group. Radiative UPSILON decay studies fail to confirm the zeta(8.3) and begin to place useful limits on Higgs bosons. First results from an experiment at Fermilab on low-background hadronic production of UPSILON states are shown. Accurate measurements of chi/sub b/(1P) masses by the ARGUS collaboration are noted, and interpreted as favoring scalar quark confinement. Studies of t and other heavy quarks will probe the q anti q interaction below 0.05 fm, are likely to be strongly affected by t anti t-Z interference, and can provide varied information on Higgs bosons. 144 refs., 21 figs
Quark-meson coupling model with short-range quark-quark interactions
Saito, Koichi; Tsushima, Kazuo
2000-01-01
Short-range quark-quark correlations are introduced into the quark-meson coupling (QMC) model phenomenologically. We study the effect of the correlations on the structure of the nucleon in dense nuclear matter. With the addition of correlations, the saturation curve for symmetric nuclear matter is much improved at high density.
Chemical Evolution of Strongly Interacting Quark-Gluon Plasma
International Nuclear Information System (INIS)
At very initial stage of relativistic heavy ion collisions a wave of quark-gluon matter is produced from the break-up of the strong color electric field and then thermalizes at a short time scale (~1 fm/c). However, the quark-gluon plasma (QGP) system is far out of chemical equilibrium, especially for the heavy quarks which are supposed to reach chemical equilibrium much late. In this paper a continuing quark production picture for strongly interacting QGP system is derived, using the quark number susceptibilities and the equation of state; both of them are from the results calculated by the Wuppertal-Budapest lattice QCD collaboration. We find that the densities of light quarks increase by 75% from the temperature T=400 MeV to T=150 MeV, while the density of strange quark annihilates by 18% in the temperature region. We also offer a discussion on how this late production of quarks affects the final charge-charge correlations
International Nuclear Information System (INIS)
Years after its discovery in 1995 by CDF and D0, the top quark still undergoes intense investigations at the Tevatron. Using up to the full Run II data sample, new measurements of top quark production and properties by the D0 Collaboration are presented. In particular, the first observation of single top quark s-channel production, the measurement of differential t t-bar distributions, forward-backward t t-bar asymmetry, a new measurement of the top quark mass, and a measurement of the top quark charge are discussed
Beauty-quark and charm-quark pair production asymmetries at LHCb
Gauld, Rhorry; Haisch, Ulrich; Pecjak, Ben D.; Re, Emanuele
2015-08-01
The LHCb Collaboration has recently performed a first measurement of the angular production asymmetry in the distribution of beauty quarks and antiquarks at a hadron collider. We calculate the corresponding standard model prediction for this asymmetry at fixed order in perturbation theory. Our results show good agreement with the data, which are provided differentially for three bins in the invariant mass of the b b ¯ system. We also present similar predictions for both beauty-quark and charm-quark final states within the LHCb acceptance for a collision energy of √{s }=13 TeV . We finally point out that a measurement of the ratio of the b b ¯ and c c ¯ cross sections may be useful for experimentally validating charm-tagging efficiencies.
Weak decays of the Bc meson to Bs and B mesons in the relativistic quark model
International Nuclear Information System (INIS)
Semileptonic and non-leptonic decays of the Bc meson to Bs and B mesons, caused by the c→s,d quark transitions, are studied in the framework of the relativistic quark model. The heavy quark expansion in inverse powers of the active c and spectator anti b quark is used to simplify calculations while the final s and d quarks in the Bs and B mesons are treated relativistically. The decay form factors are explicitly expressed through the overlap integrals of the meson wave functions in the whole accessible kinematical range. The obtained results are compared with the predictions of other approaches. (orig.)
Quark-Number Susceptibility at Finite Chemical Potential and Zero Temperature
Institute of Scientific and Technical Information of China (English)
HE Deng-Ke; JIANG Yu; FENG Hong-Tao; SUN Wei-Min; ZONG Hong-Shi
2008-01-01
We give a direct method for calculating the quark-number susceptibility at finite chemical potential and zero temperature.In this approach the quark-number susceptibility is totally determined by G[μ](p)(the dressed quark propagator at finite chemical potential μ).By applying the general result in our previous study[Phys.Rev.C 71(2005)015205,034901,73 (2006) 016004] G[μ](p)is calculated from the model quark propagator proposed by Pagels and Stokar[Phys.Rev.D 20(1979)2947].The full analytic expression of the quark-number susceptibility at finite μ and zero T is obtained.
Strange quark matter and quark stars with the Dyson-Schwinger quark model
Chen, H; Schulze, H -J
2016-01-01
We calculate the equation of state of strange quark matter and the interior structure of strange quark stars in a Dyson-Schwinger quark model within rainbow or Ball-Chiu vertex approximation. We emphasize constraints on the parameter space of the model due to stability conditions of ordinary nuclear matter. Respecting these constraints, we find that the maximum mass of strange quark stars is about 1.9 solar masses, and typical radii are 9--11 km. We obtain an energy release as large as $3.6 \\times 10^{53}\\,\\text{erg}$ from conversion of neutron stars into strange quark stars.
Top quark decays in extended models
International Nuclear Information System (INIS)
We evaluate the FCNC decays t → H0 + c at tree-level and t → γ + c at one-loop level in the context of Alternative Left-Right symmetric Models (ALRM) with extra isosinglet heavy fermions; in the first case, FCNC decays occurs at tree-level and they are only suppressed by the mixing between ordinary top and charm quarks. (author)
Enhancement of new physics signal sensitivity with mistagged charm quarks
Kim, Doojin; Park, Myeonghun
2016-07-01
We investigate the potential for enhancing search sensitivity for signals having charm quarks in the final state, using the sizable bottom-mistagging rate for charm quarks at the LHC. Provided that the relevant background processes contain light quarks instead of charm quarks, the application of b-tagging on charm quark-initiated jets enables us to reject more background events than signal ones due to the relatively small mistagging rate for light quarks. The basic idea is tested with two rare top decay processes: i) t → ch → cb b bar and ii) t → bH+ → b b bar c where h and H+ denote the Standard Model-like higgs boson and a charged higgs boson, respectively. The major background source is a hadronic top quark decay such as t → bW+ → b s bar c. We test our method with Monte Carlo simulation at the LHC 14 TeV, and find that the signal-over-background ratio can be increased by a factor of O (6- 7) with a suitably designed (heavy) flavor tagging algorithm and scheme.
Enhancement of new physics signal sensitivity with mistagged charm quarks
Directory of Open Access Journals (Sweden)
Doojin Kim
2016-07-01
Full Text Available We investigate the potential for enhancing search sensitivity for signals having charm quarks in the final state, using the sizable bottom-mistagging rate for charm quarks at the LHC. Provided that the relevant background processes contain light quarks instead of charm quarks, the application of b-tagging on charm quark-initiated jets enables us to reject more background events than signal ones due to the relatively small mistagging rate for light quarks. The basic idea is tested with two rare top decay processes: i t→ch→cbb¯ and ii t→bH+→bb¯c where h and H+ denote the Standard Model-like higgs boson and a charged higgs boson, respectively. The major background source is a hadronic top quark decay such as t→bW+→bs¯c. We test our method with Monte Carlo simulation at the LHC 14 TeV, and find that the signal-over-background ratio can be increased by a factor of O(6–7 with a suitably designed (heavy flavor tagging algorithm and scheme.
International Nuclear Information System (INIS)
The alchemy of the production of states containing the heavy quarks in hadron-hadron or photon-hadron collisions offers an opportunity to study hadronic dynamics in a manner not readily available elsewhere. The focus is on an approach based on a simple interpretation of QCD developed at Illinois and Argonne. This approach seems to offer the possibility of forming a connection between the dynamics of heavy particle production and recent developments in the theory of large-transverse-momentum processes. It is very interesting to see how the connection with large-P/sub T/ emerges from a fairly reasonable model. In the model discussed, the production of heavy quarks in photoproduction is thought of as arising from diagrams which constitute the lowest-order-QCD process available and are considered applicable either for a real photon or for a virtual photon arising from inelastic lepton scattering. 25 references
Smith, F T
1997-01-01
From sets and simple operations on sets, a Feynman Checkerboard physics model is constructed that allows computation of force strength constants and constituent mass ratios of elementary particles, giving a tree level constituent Truth Quark (top quark) mass of roughly 130 GeV, which is (in my opinion) supported by dileptonic events and some semileptonic events. See http://galaxy.cau.edu/tsmith/HDFCmodel.html and http://www.innerx.net/personal/tsmith/HDFCmodel.html This model is similar to a Lie algebra D4-D5-E6 model: Chapter 1 - Introduction. Chapter 2 - From Sets to Clifford Algebras. Chapter 3 - Octonions and E8 lattices. Chapter 4 - E8 spacetime and particles. Chapter 5 - HyperDiamond Lattices. Chapter 6 - Internal Symmetry Space. Chapter 7 - Feynman Checkerboards. Chapter 8 - Charge = Amplitude to Emit Gauge Boson. Chapter 9 - Mass = Amplitude to Change Direction. Chapter 10 - Protons, Pions, and Physical Gravitons.
The Multimedia Project Quarked!
Bean, Alice
2011-01-01
Can exposure to fundamental ideas about the nature of matter help motivate children in math and science and support the development of their understanding of these ideas later? Physicists, designers, and museum educators at the University of Kansas created the Quarked!(tm) Adventures in the subatomic Universe project to provide an opportunity for youth to explore the subatomic world in a fun and user friendly way. The project components include a website (located at http://www.quarked.org) and hands-on education programs. These are described and assessment results are presented. Questions addressed include the following. Can you engage elementary and middle school aged children with concepts related to particle physics? Can young children make sense of something they can't directly see? Do teachers think the material is relevant to their students?
Supersymmetric top quark decays
International Nuclear Information System (INIS)
The supersymmetric decays of the top quark into charged Higgs plus bottom, t → H+b, and into the supersymmetric partner of the top (u1) plus the lightest neutralino (χ10), t → u1χ10, are discussed within the framework of the Minimal Supersymmetric Standard Model with radiatively induced breaking of the gauge group SU(2) x U(1). The possibility of detecting these decays at present, i.e. given the available bounds on supersymmetric parameters, is compared with the situation a Next e+e- Linear Collider would face if supersymmetric particles were still undiscovered at LEP II. The indirect implications for t → H+b and t → u1χ10 of a measurement of the bottom quark decay b → sγ at the Standard Model level are taken into account. (orig.)
Heavy-baryon quark model picture from lattice QCD
Vijande, J; Garcilazo, H
2015-01-01
The ground state and excited spectra of baryons containing three identical heavy quarks, $b$ or $c$, have been recently calculated in nonperturbative lattice QCD. The energy of positive and negative parity excitations has been determined with high precision. Lattice results constitute a unique opportunity to learn about the quark-confinement mechanism as well as elucidating our knowledge about the nature of the strong force. We analyze the nonperturbative lattice QCD results by means of heavy-quark static potentials derived using SU(3) lattice QCD. We make use of different numerical techniques for the three-body problem.
Anomalous single top quark production at the LHC
Najafabadi, M. Mohammadi; Pooya, G.
2010-09-01
The anomalous top quark interactions with gluon (tug, tcg) allow the production of single top quarks at the Large Hadron Collider (LHC). Using the angular distribution of the charged lepton from the W boson in the top decay, we show that with the data of 10 fb-1 of integrated luminosity and in the collisions with the center of mass energy of 14 TeV, the anomalous up and charm quarks coupling parameters κu, c/Λ can be measured down to 0.005 and 0.007 TeV-1, respectively.
Embedding of leptons and quarks in octonionic structures
International Nuclear Information System (INIS)
All leptons and quarks are united into the Dirac spinor hyperfield constructed over systems of nonassociative postoctonium numbers obtained by the Cayley-Dickson iterative process for octonions. Spontaneously broken G2xSU(3)LxU(1) gauge symmetry is formulted and the colour SU(3)c quark symmetry is explained as the unbroken subgroup of G2, the broken automorphism group of postoctonium hypernumbers. The right eigenvalues of the electric charges of leptons and quarks (of two generations) are obtained from the requirement of the invariance of trilinear associative form under the phase-transformation. 8 refs
Quark-antiquark pairs in the quark model
International Nuclear Information System (INIS)
We study the structure of the spin of the proton and the Λ hyperon in an unquenched quark model which incorporates the effects of quark-antiquark pair creation via a microscopic, QCD-inspired, quark-antiquark creation mechanism. It is shown that the inclusion of the qq-bar pairs leads to a sizeable contribution of the orbital angular momentum to the spin of the proton and the Λ hyperon.
Simula, Silvano
2001-01-01
The application of relativistic constituent quark models to the evaluation of the electromagnetic properties of the nucleon and its resonances is addressed. The role of the pair creation process in the Feynmann triangle diagram is discussed and the importance both of choosing the light-front formalism and of using a Breit frame where the plus component of the four-momentum transfer is vanishing, is stressed. The nucleon elastic form factors are calculated free of spurious effects related to t...
Santopinto, E
2015-01-01
In this contribution, we briefly discuss the results for charmonium and bottomonium spectra with self-energy corrections in the unquenched quark model, due to the coupling to the meson-meson continuum. The UQM formalism can be extended to include also the effects of hybrid mesons, i.e. hybrid loops. Finally, we discuss the results of a calculation of hybrid mesons spectrum in Coulomb Gauge QCD.
Pallante, E.; R. Petronzio(INFN RM2)
1994-01-01
We construct an effective Lagrangian for low energy hadronic interactions through an infinite expansion in inverse powers of the low energy cutoff Î›Ï‡ of all possible chiral invariant non-renormalizable interactions between quarks and mesons degrees of freedom arising from the bosonization of a general Nambu-Jona Lasinio type Lagrangian including all multiquark effective interactions. We restrict our analysis to the leading terms in the 1/Nc expansion and to the divergent part of the resonan...
Rafelski, Johann
2007-01-01
Matter in its present form was formed when our Universe emerged from the quark-gluon phase (QGP) at about 30mus into its evolution. To explore this early period in the laboratory, we study highly excited matter formed in relativistic heavy ion collision experiments: heavy nuclei crash into each other, and form compressed and energetically excited nuclear matter, resembling in its key features the stuff which filled the early Universe. In these experiments we further explore the physics of the...
Nayak, Tapan; Sarkar, Sourav
2014-01-01
At extremely high temperatures and densities, protons and neutrons may dissolve into a "soup" of quarks and gluons, called the Quark-Gluon Plasma (QGP). For a few microseconds, shortly after the Big Bang, the Universe was filled with the QGP matter. The search and study of Quark-Gluon Plasma (QGP) is one of the most fundamental research topics of our times. The QGP matter has been probed by colliding heavy ions at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory, New York and the Large Hadron Collider at CERN, Geneva. By colliding heavy-ions at a speed close to that of light, scientists aim to obtain - albeit over a tiny volume of the size of a nucleus and for an infinitesimally short instant - a QGP state. This QGP state can be observed by dedicated experiments, as it reverts to hadronic matter through expansion and cooling. This volume presents some of the current theoretical and experimental understandings in the field of QGP.
International Nuclear Information System (INIS)
Full text: Recently, the question of the charm quark contribution to the thermodynamics of the QGP has received some attention. In particular at the high temperatures that can be reached in heavy ion collisions at the LHC a better understanding the thermal contribution of charm to bulk thermodynamics will become relevant. Lattice QCD can provide an answer to this question, but fully dynamical, 4-flavor ensembles do not yet exist. The large charm quark mass also is expected to introduce additional cut-off effects. Nonetheless, as an exploratory study, we recently calculated the second-, fourth- and sixth-order susceptibilities for the charm quark in the partially quenched approximation using the p4 action. We found that our results were in good agreement with perturbative estimates for these quantities. We also studied correlations between charm and the lighter flavors. We compared these quantities to simple quasiparticle and resonance gas models. Lastly, we shall also comment on calculations of the charm's contribution to the pressure within the partially quenched approximation. (author)
Fields, symmetries, and quarks
International Nuclear Information System (INIS)
'Fields, symmetries, and quarks' covers elements of quantum field theory, symmetries, gauge field theories and phenomenological descriptions of hadrons, with special emphasis on topics relevant to nuclear physics. It is aimed at nuclear physicists in general and at scientists who need a working knowledge of field theory, symmetry principles of elementary particles and their interactions and the quark structure of hadrons. The book starts out with an elementary introduction into classical field theory and its quantization. As gauge field theories require a working knowledge of global symmetries in field theories this topic is then discussed in detail. The following part is concerned with the general structure of gauge field theories and contains a thorough discussion of the still less widely known features of Non-Abelian gauge field theories. Quantum Chromodynamics (QCD), which is important for the understanding of hadronic matter, is discussed in the next section together with the quark compositions of hadrons. The last two chapters give a detailed discussion of phenomenological bag-models. The MIT bag is discussed, so that all theoretical calculations can be followed step by step. Since in all other bag-models the calculational methods and steps are essentially identical, this chapter should enable the reader to actually perform such calculations unaided. A last chapter finally discusses the topological bag-models which have become quite popular over the last few years. (orig.)
Color Superconducting Quark Matter in Neutron Stars
Heiselberg, H.
1999-01-01
Color superconductivity in quark matter is studied for electrically charge neutral neutron star matter in $\\beta$-equilibrium. Both bulk quark matter and mixed phases of quark and nuclear matter are treated. The electron chemical potential and strange quark mass affect the various quark chemical potentials and therefore also the color superconductivity due to dicolor pairing or color-flavor locking.
Top Quark Physics -- a Popular Review
Lampe, Bodo
1995-01-01
The top quark has been discovered at FERMILAB last year. The following features of top quark physics will be discussed in this article: the top quark in the standard model production and decay of the top quark in proton collisions (direct evidence for top) virtual effects of top quarks in electroweak observables (indirect evidence for top)
Parametrization of Fully Dressed Quark Propagator
Institute of Scientific and Technical Information of China (English)
MA Wei-Xing; ZHU Ji-Zhen; ZHOU Li-Juan; SHEN Peng-Nian; HU Zhao-Hui
2005-01-01
Based on an extensive study of the Dyson-Schwinger equations for a fully dressed quark propagator in the "rainbow" approximation, a parametrized form of the quark propagator is suggested. The corresponding quark selfform of the quark propagator proposed in this work describes a confining quark propagation, and is quite convenient to be used in any numerical calculations.
Energy Technology Data Exchange (ETDEWEB)
Messner, R. [Stanford Univ., CA (United States)
1997-01-01
This report covers preliminary measurements from SLD on heavy quark production at the Z{sup 0}, using 150,000 hadronic Z{sup 0} decays accumulated during the 1993-1995 runs. A measurement of R{sub b} with a lifetime double tag is presented. The high electron beam polarization of the SLC is employed in the direct measurement of the parity-violating parameters A{sub b} and A{sub c} by use of the left-right forward-backward asymmetry. The lifetimes of B{sup +} and B{sup 0} mesons have been measured by two analyses. The first identifies semileptonic decays of B mesons with high (p,p{sub t}) leptons; the second analysis isolates a sample of B meson decays with a two-dimensional impact parameter tag and reconstructs the decay length and charge using a topological vertex reconstruction method.
International Nuclear Information System (INIS)
The structure of this report is as follows. Section 2 looks at quarks, starting with a review of previous experimental searches and continuing with the phenomenology of the different varieties of quark which are mentioned above. We study the direct production and detection of conventional fractionally charged quarks, of strongly interacting coloured quarks with appetite, and of quarks with indeterminate mass or integer charge. We also examine the search for indirect manifestations of quarks with non-standard colour, or with substructure. Section 3 deals with monopoles, starting with a summary of motivations for their existence, and their expected properties, as well as a review of the previous searches. It continues with a survey of the different ways of looking for conventional magnetic monopoles and other possible topological excitations in gauge theories. (orig./HSI)
Validity of Parametrized Quark Propagator
Institute of Scientific and Technical Information of China (English)
ZHU Ji-Zhen; ZHOU Li-Juan; MA Wei-Xing
2005-01-01
Based on an extensively study of the Dyson-Schwinger equations for a fully dressed quark propagator in the "rainbow" approximation, a parametrized fully dressed quark propagator is proposed in this paper. The parametrized propagator describes a confining quark propagator in hadron since it is analytic everywhere in complex p2-plane and has no Lemmann representation. The validity of the new propagator is discussed by comparing its predictions on selfenergy functions Af(p2), Bf(p2) and effective mass Mf(p2) of quark with flavor f to their corresponding theoretical results produced by Dyson-Schwinger equations. Our comparison shows that the parametrized quark propagator is a good approximation to the fully dressed quark propagator given by the solutions of Dyson-Schwinger equations in the rainbow approximation and is convenient to use in any theoretical calculations.
Validity of Parametrized Quark Propagator
Institute of Scientific and Technical Information of China (English)
ZHUJi-Zhen; ZHOULi-Juan; MAWei-Xing
2005-01-01
Based on an extensively study of the Dyson-Schwinger equations for a fully dressed quark propagator in the “rainbow”approximation, a parametrized fully dressed quark propagator is proposed in this paper. The parametrized propagator describes a confining quark propagator in hadron since it is analytic everywhere in complex p2-plane and has no Lemmann representation. The validity of the new propagator is discussed by comparing its predictions on selfenergy functions A/(p2), Bl(p2) and effective mass M$(p2) of quark with flavor f to their corresponding theoretical results produced by Dyson-Schwinger equations. Our comparison shows that the parametrized quark propagator is a good approximation to the fully dressed quark propagator given by the solutions of Dyson-Schwinger equations in the rainbow approximation and is convenient to use in any theoretical calculations.
First determination of the electric charge of the top quark
Abazov, V M; Abolins, M; Acharya, B S; Adams, M; Adams, T; Agelou, M; Ahn, S H; Ahsan, M; Alexeev, G D; Alkhazov, G; Alton, A; Alverson, G; Alves, G A; Anastasoaie, M; Andeen, T; Anderson, S; Andrieu, B; Anzelc, M S; Arnoud, Y; Arov, M; Askew, A; Åsman, B; Assis-Jesus, A C S; Atramentov, O; Autermann, C; Avila, C; Ay, C; Badaud, F; Baden, A; Bagby, L; Baldin, B; Bandurin, D V; Banerjee, P; Banerjee, S; Barberis, E; Bargassa, P; Baringer, P; Barnes, C; Barreto, J; Bartlett, J F; Bassler, U; Bauer, D; Bean, A; Begalli, M; Begel, M; Belanger-Champagne, C; Bellantoni, L; Bellavance, A; Benítez, J A; Beri, S B; Bernardi, G; Bernhard, R; Berntzon, L; Bertram, I; Besançon, M; Beuselinck, R; Bezzubov, V A; Bhat, P C; Bhatnagar, V; Binder, M; Biscarat, C; Black, K M; Blackler, I; Blazey, G; Blekman, F; Blessing, S; Bloch, D; Bloom, K; Blumenschein, U; Böhnlein, A; Boeriu, O; Bolton, T A; Borissov, G; Bos, K; Bose, T; Brandt, A; Brock, R; Brooijmans, G; Bross, A; Brown, D; Buchanan, N J; Buchholz, D; Bühler, M; Büscher, V; Burdin, S; Burke, S; Burnett, T H; Busato, E; Buszello, C P; Butler, J M; Calfayan, P; Calvet, S; Cammin, J; Caron, S; Carvalho, W; Casey, B C K; Cason, N M; Castilla-Valdez, H; Chakraborty, D; Chan, K M; Chandra, A; Charles, F; Cheu, E; Chevallier, F; Cho, D K; Choi, S; Choudhary, B; Christofek, L; Claes, D; Clement, B; Clément, C; Coadou, Y; Cooke, M; Cooper, W E; Coppage, D; Corcoran, M; Cousinou, M C; Cox, B; Crepe-Renaudin, S; Cutts, D; Cwiok, M; Da Motta, H; Das, A; Das, M; Davies, B; Davies, G; Davis, G A; De, K; de Jong, P; De Jong, S J; De La Cruz-Burelo, E; De Oliveira Martins, C; Degenhardt, J D; Déliot, F; Demarteau, M; Demina, R; Demine, P; Denisov, D; Denisov, S P; Desai, S; Diehl, H T; Diesburg, M; Doidge, M; Dominguez, A; Dong, H; Dudko, L V; Duflot, L; Dugad, S R; Duggan, D; Duperrin, A; Dyer, J; Dyshkant, A; Eads, M; Edmunds, D; Edwards, T; Ellison, J; Elmsheuser, J; Elvira, V D; Eno, S; Ermolov, P; Evans, H; Evdokimov, A; Evdokimov, V N; Fatakia, S N; Feligioni, L; Ferapontov, A V; Ferbel, T; Fiedler, F; Filthaut, F; Fisher, W; Fisk, H E; Fleck, I; Ford, M; Fortner, M; Fox, H; Fu, S; Fuess, S; Gadfort, T; Galea, C F; Gallas, E; Galyaev, E; García, C; García-Bellido, A; Gardner, J; Gavrilov, V; Gay, A; Gay, P; Gelé, D; Gelhaus, R; Gerber, C E; Gershtein, Yu; Gillberg, D; Ginther, G; Gollub, N; Gómez, B; Goussiou, A; Grannis, P D; Greenlee, H; Greenwood, Z D; Gregores, E M; Grenier, G; Gris, P; Grivaz, J F; Grünendahl, S; Grünewald, M W; Guo, F; Guo, J; Gutíerrez, G; Gutíerrez, P; Haas, A; Hadley, N J; Haefner, P; Hagopian, S; Haley, J; Hall, I; Hall, R E; Han, L; Hanagaki, K; Hansson, P; Harder, K; Harel, A; Harrington, R; Hauptman, J M; Hauser, R; Hays, J; Hebbeker, T; Hedin, D; Hegeman, J G; Heinmiller, J M; Heinson, A P; Heintz, U; Hensel, C; Herner, K; Hesketh, G; Hildreth, M D; Hirosky, R; Hobbs, J D; Hoeneisen, B; Hoeth, H; Hohlfeld, M; Hong, S J; Hooper, R; Houben, P; Hu, Y; Hubacek, Z; Hynek, V; Iashvili, I; Illingworth, R; Ito, A S; Jabeen, S; Jaffré, M; Jain, S; Jakobs, K; Jarvis, C; Jenkins, A; Jesik, R; Johns, K; Johnson, C; Johnson, M; Jonckheere, A; Jonsson, P; Juste, A; Käfer, D; Kahn, S; Kajfasz, E; Kalinin, A M; Kalk, J M; Kalk, J R; Kappler, S; Karmanov, D; Kasper, J; Kasper, P; Katsanos, I; Kau, D; Kaur, R; Kehoe, R; Kermiche, S; Khalatyan, N; Khanov, A; Kharchilava, A I; Kharzheev, Yu M; Khatidze, D; Kim, H; Kim, T J; Kirby, M H; Klima, B; Kohli, J M; Konrath, J P; Kopal, M; Korablev, V M; Kotcher, J; Kothari, B; Koubarovsky, A; Kozelov, A V; Kozminski, J; Krop, D; Kryemadhi, A; Kühl, T; Kumar, A; Kunori, S; Kupco, A; Kurca, T; Kvita, J; Lammers, S; Landsberg, G L; Lazoflores, J; Le Bihan, A C; Lebrun, P; Lee, W M; Leflat, A; Lehner, F; Lesne, V; Lévêque, J; Lewis, P; Li, J; Li, Q Z; Lima, J G R; Lincoln, D; Linnemann, J; Lipaev, V V; Lipton, R; Liu, Z; Lobo, L; Lobodenko, A; Lokajícek, M; Lounis, A; Love, P; Lubatti, H J; Lynker, M; Lyon, A L; Maciel, A K A; Madaras, R J; Mättig, P; Magass, C; Magerkurth, A; Magnan, A M; Makovec, N; Mal, P K; Malbouisson, H B; Malik, S; Malyshev, V L; Mao, H S; Maravin, Y; Martens, M; McCarthy, R; Meder, D; Melnitchouk, A; Mendes, A; Mendoza, L; Merkin, M; Merritt, K W; Meyer, A; Meyer, J; Michaut, M; Miettinen, H; Millet, T; Mitrevski, J; Molina, J; Mondal, N K; Monk, J; Moore, R W; Moulik, T; Muanza, G S; Mulders, M; Mulhearn, M; Mundim, L; Mutaf, Y D; Nagy, E; Naimuddin, M; Narain, M; Naumann, N A; Neal, H A; Negret, J P; Neustroev, P; Nöding, C; Nomerotski, A; Novaes, S F; Nunnemann, T; O'Dell, V; O'Neil, D C; Obrant, G; Oguri, V; Oliveira, N; Oshima, N; Otec, R; Oteroy-Garzon, G J; Owen, M; Padley, P; Parashar, N; Park, S J; Park, S K; Parsons, J; Partridge, R; Parua, N; Patwa, A; Pawloski, G; Perea, P M; Pérez, E; Peters, K; Petroff, P; Petteni, M; Piegaia, R; Piper, J; Pleier, M A; Podesta-Lerma, P L M; Podstavkov, V M; Pogorelov, Y; Pol, M E; Pompos, A; Pope, B G; Popov, A V; Potter, C; Prado da Silva, W L; Prosper, H B; Protopopescu, S D; Qian, J; Quadt, A; Quinn, B; Rangel, M S; Rani, K J; Ranjan, K; Ratoff, P N; Renkel, P; Reucroft, S; Rijssenbeek, M; Ripp-Baudot, I; Rizatdinova, F K; Robinson, S; Rodrigues, R F; Royon, C; Rubinov, P; Ruchti, R; Rud, V I; Sajot, G; Sánchez-Hernández, A; Sanders, M P; Santoro, A F S; Savage, G; Sawyer, L; Scanlon, T; Schaile, A D; Schamberger, R D; Scheglov, Y; Schellman, H; Schieferdecker, P; Schmitt, C; Schwanenberger, C; Schwartzman, A; Schwienhorst, R; Sekaric, J; Sen-Gupta, S; Severini, H; Shabalina, E; Shamim, M; Shary, V; Shchukin, A A; Shephard, W D; Shivpuri, R K; Shpakov, D; Siccardi, V; Sidwell, R A; Simák, V; Sirotenko, V I; Skubic, P L; Slattery, P F; Smith, R P; Snow, G R; Snow, J; Snyder, S; Söldner-Rembold, S; Song, X; Sonnenschein, L; Sopczak, A; Sosebee, M; Soustruznik, K; Souza, M; Spurlock, B; Stark, J; Steele, J; Stolin, V; Stone, A; Stoyanova, D A; Strandberg, J; Strandberg, S; Strang, M A; Strauss, M; Ströhmer, R; Strom, D; Strovink, M; Stutte, L; Sumowidagdo, S; Sznajder, A; Talby, M; Tamburello, P; Taylor, W; Telford, P; Temple, J; Tiller, B; Titov, M; Tokmenin, V V; Tomoto, M; Toole, T; Torchiani, I; Towers, S; Trefzger, T; Trincaz-Duvoid, S; Tsybychev, D; Tuchming, B; Tully, C; Turcot, A S; Tuts, P M; Unalan, R; Uvarov, L; Uvarov, S; Uzunyan, S; Vachon, B; vanden Berg, P J; Van Kooten, R; Van Leeuwen, W M; Varelas, N; Varnes, E W; Vartapetian, A H; Vasilyev, I A; Vaupel, M; Verdier, P; Vertogradov, L S; Verzocchi, M; Villeneuve-Séguier, F; Vint, P; Vlimant, J R; Von Törne, E; Voutilainen, M; Vreeswijk, M; Wahl, H D; Wang, L; Wang, M H L; Warchol, J; Watts, G; Wayne, M; Weber, M; Weerts, H; Wermes, N; Wetstein, M; White, A; Wicke, D; Wilson, G W; Wimpenny, S J; Wobisch, M; Womersley, J; Wood, D R; Wyatt, T R; Xie, Y; Xuan, N; Yacoob, S; Yamada, R; Yan, M; Yasuda, T; Yatsunenko, Y A; Yip, K; Yoo, H D; Youn, S W; Yu, C; Yu, J; Yurkewicz, A; Zatserklyaniy, A; Zeitnitz, C; Zhang, D; Zhao, T; Zhou, B; Zhu, J; Zielinski, M; Zieminska, D; Zieminski, A; Zutshi, V; Zverev, E G
2007-01-01
We present the first determination of the electric charge of the top quark, using top quark pairs (ttbar) produced in ppbar collisions at sqrt(s)=1.96 TeV by the Fermilab Tevatron collider. We use 370 pb-1 of data collected by the D0 experiment and select events with at least one high transverse momentum electron or muon, high transverse energy imbalance, and four or more jets. We discriminate between b- and bbar-quark jets by using the charge and momenta of tracks within the jet cones. The data is consistent with the expected electric charge, |q|=2e/3. We exclude, at the 92% C.L., that the sample is solely due to the production of exotic quark pairs QQbar with |q|=4e/3. We place an upper limit on the fraction of QQbar pairs rho < 0.80 at the 90% C.L.
Top quark pair production at NNLO in the quark-antiquark channel
Abelof, Gabriel; Majer, Imre
2015-01-01
We present the derivation of the NNLO two-parton final state contributions to top pair production in the quark-antiquark channel proportionnal to the leading colour factor $N_c^2$. Together with the three and four-parton NNLO contributions derived in a previous publication, this enables us to complete the phenomenologically most important NNLO corrections to top pair hadro-production in this channel. We derive this two-parton contribution using the massive extension of the NNLO antenna subtraction formalism and implement those corrections in a parton-level event generator providing full kinematical information on all final state particles. Combining the new leading-colour contributions with the light quark contributions derived previously, we present NNLO differential distributions for LHC and Tevatron. We also compute the differential top quark forward-backward asymmetry at Tevatron and find that our results are in good agreement with the measurements by the D0 collaboration.
Quark matter or new particles?
Michel, F. Curtis
1988-01-01
It has been argued that compression of nuclear matter to somewhat higher densities may lead to the formation of stable quark matter. A plausible alternative, which leads to radically new astrophysical scenarios, is that the stability of quark matter simply represents the stability of new particles compounded of quarks. A specific example is the SU(3)-symmetric version of the alpha particle, composed of spin-zero pairs of each of the baryon octet (an 'octet' particle).
Phenomenology of heavy quark systems
International Nuclear Information System (INIS)
The spectroscopy of heavy quark systems is examined with regards to spin independent and spin dependent potentials. It is shown that a qualitative picture exists of the spin-independent forces, and that a semi-quantitative understanding exists for the spin-dependent effects. A brief review is then given of the subject of the decays of hadrons containing heavy quarks, including weak decays at the quark level, and describing corrections to the spectator model
Antinori, Federico; Bass, Steffen A.; Bellwied, Rene; Ullrich, Thomas; Velkovska, Julia; Wiedemann, Urs
2005-04-01
Why another conference devoted to ultra-relativistic heavy-ion physics? As we looked around the landscape of the existing international conferences and workshops, we realized that there was not a single one tailored to the people who are most directly involved with the actual research work: students, post-docs, and junior faculty/research scientists. Of course there are schools, but that was not what we had in mind. We wanted a meeting where young researchers could come together to discuss in depth the physics that they are working on without any hindrance. The major conferences have very limited time for discussions which is often shared amongst the most established. This leaves little room for young people to ask their questions and to get the detailed feedback which they deserve and which satisfies their curiosity. A discussion-driven workshop, centering on those without whom there will be no future—that seemed like what was needed. And thus the Hot Quarks workshop was born. The aim of Hot Quarks was to enhance the direct exchange of scientific information among the younger members of the community, from both experiment and theory. Participation was by invitation only in order to emphasize the contributions from junior researchers. This approach makes the workshop unique among the many forums in the field. For young scientists it represented an opportunity for exposure that they would not have had in one of the major conferences. The hope is that this meeting has helped to stimulate the next generation of scientists in our field and, at the same time, strengthened their sense of community. It all came together from 18 24 July 2004, when the 77 participants met at The Inn at Snakedance in the Taos Ski Valley, New Mexico, USA, for the first Hot Quarks workshop. Photograph Participants gather in the sunshine at the foot of the Taos Ski Valley chairlift. By all accounts, Hot Quarks 2004 was a great success. Every participant had the opportunity to present her or
Brown, Laurie Mark; Dresden, Max; Hoddeson, Lillian
2009-01-01
Part I. Introduction; 1. Pions to quarks: particle physics in the 1950s Laurie M Brown, Max Dresden and Lillian Hoddeson; 2. Particle physics in the early 1950s Chen Ning Yang; 3. An historian's interest in particle physics J. L. Heilbron; Part II. Particle discoveries in cosmic rays; 4. Cosmic-ray cloud-chamber contributions to the discovery of the strange particles in the decade 1947-1957 George D. Rochester; 5. Cosmic-ray work with emulsions in the 1940s and 1950s Donald H. Perkins; Part III. High-energy nuclear physics; Learning about nucleon resonances with pion photoproduction Robert L. Walker; 7. A personal view of nucleon structure as revealed by electron scattering Robert Hofstadter; 8. Comments on electromagnetic form factors of the nucleon Robert G. Sachs and Kameshwar C. Wali; Part IV. The new laboratory; 9. The making of an accelerator physicist Matthew Sands; 10. Accelerator design and construction in the 1950s John P. Blewett; 11. Early history of the Cosmotron and AGS Ernest D. Courant; 12. Panel on accelerators and detectors in the 1950s Lawrence W. Jones, Luis W. Alvarez, Ugo Amaldi, Robert Hofstadter, Donald W. Kerst, Robert R. Wilson; 13. Accelerators and the Midwestern Universities Research Association in the 1950s Donald W. Kerst; 14. Bubbles, sparks and the postwar laboratory Peter Galison; 15. Development of the discharge (spark) chamber in Japan in the 1950s Shuji Fukui; 16. Early work at the Bevatron: a personal account Gerson Goldhaber; 17. The discovery of the antiproton Owen Chamberlain; 18. On the antiproton discovery Oreste Piccioni; Part V. The Strange Particles; 19. The hydrogen bubble chamber and the strange resonances Luis W. Alvarez; 20. A particular view of particle physics in the fifties Jack Steinberger; 21. Strange particles William Chinowsky; 22. Strange particles: production by Cosmotron beams as observed in diffusion cloud chambers William B. Fowler; 23. From the 1940s into the 1950s Abraham Pais; Part VI. Detection of the
Simulations with dynamical HISQ quarks
Bazavov, A; DeTar, C; Freeman, W; Gottlieb, Steven; Heller, U M; Hetrick, J E; Laiho, J; Levkova, L; Oktay, M; Osborn, J; Sugar, R L; Toussaint, D; Van de Water, R S
2010-01-01
We report on the status of a program of generating and using configurations with four flavors of dynamical quarks, using the HISQ action. We study the lattice spacing dependence of physical quantities in these simulations, using runs at several lattice spacings, but with the light quark mass held fixed at two tenths of the strange quark mass. We find that the lattice artifacts in the HISQ simulations are much smaller than those in the asqtad simulations at the same lattice spacings and quark masses. We also discuss methods for setting the scale, or assigning a lattice spacing to ensembles run at unphysical parameters.
Production of Heavy Quarks Close to Threshold
Adel, K.; Ynduráin, F. J.
1995-01-01
We calculate production by vector and axial currents of heavy quark pairs ($c\\bar{c}$, $b\\bar{b}$, $t\\bar{t}$) close to threshold. We take into account strong interaction contributions (including radiative corrections and leading nonperturbative effects) by using the Fermi-Watson final state interaction theorem. We use the results obtained to compare with experiment for open production of $c\\bar{c}$, $b\\bar{b}$ near threshold, and to give a reliable estimate of the so-called ``threshold effec...
Systematics of heavy quark production at RHIC
Energy Technology Data Exchange (ETDEWEB)
Vogt, R.
2002-01-30
We discuss a program for systematic studies of heavy quark production in pp, pA and AA interactions. The Q{ovr Q} production cross sections themselves cannot be accurately predicted to better than 50% at RHIC. For studies of deviations in Q{ovr Q} production such as those by nuclear shadowing and heavy quark energy loss, the pp cross-section thus needs to be measured. We then show that the ratio of pA to pp dilepton mass distributions can provide a measurement of the nuclear gluon distribution. With total rates and nuclear shadowing under control it is easier to study energy loss and to use c{ovr c} as a normalization of J/{Psi} production.
Quark and Gluon Relaxation in Quark-Gluon Plasmas
Heiselberg, H.; Pethick, C. J.
1993-01-01
The quasiparticle decay rates for quarks and gluons in quark-gluon plasmas are calculated by solving the kinetic equation. Introducing an infrared cutoff to allow for nonperturbative effects, we evaluate the quasiparticle lifetime at momenta greater than the inverse Debye screening length to leading order in the coupling constant.
Fluctuation sound absorption in quark matter
Kerbikov, B O
2016-01-01
We investigate the sound absorption in quark matter due to the interaction of the sound wave with the precritical fluctuations of the diquark-pair field above $T_c$. The soft collective mode of the pair field is derived using the time dependent Ginzburg-Landau functional with random Langevin forces. The strong absorption near the phase transition line may be viewed as a manifestation of the Mandelshtam-Leontovich slow relaxation time theory.
LHCb pentaquarks in constituent quark models
Ortega, P G; Fernández, F
2016-01-01
The recently discovered $P_c(4380)^+$ and $P_c(4450)^+$ states at LHCb have masses close to the $\\bar D\\Sigma_c^*$ and $\\bar D^*\\Sigma_c$ thresholds, respectively, which suggest that they may have significant meson-baryon molecular components. We analyze these states in the framework of a constituent quark model which has been applied to a wide range of hadronic observables, being the model parameters, therefore, completely constrained. The $P_c(4380)^+$ and $P_c(4450)^+$ are studied as molecular states composed by charmed baryons and open charm mesons. Several bound states with the proper binding energy are found in the $\\bar D\\Sigma_c^*$ and $\\bar D^*\\Sigma_c$ channels. We discuss the possible assignments of these states from their decay widths. Moreover, two more states are predicted, associated with the $\\bar D\\Sigma_c$ and $\\bar D^* \\Sigma_c^*$ thresholds.
Top Quark Studies at Hadron Colliders
Sinervo, Pekka K.
1996-01-01
The techniques used to study top quarks at hadron colliders are presented. The analyses that discovered the top quark are described, with emphasis on the techniques used to tag b-quark jets in candidate events. The most recent measurements of top quark properties by the CDF and DZero collaborations are reviewed, including the top quark cross section, mass, branching fractions and production properties. Future top quark studies at hadron colliders are discussed, and predictions for event yield...
The Discovery of the Top Quark
Sinervo, P.K.
1995-12-01
The top quark and the Higgs boson are the heaviest elementary particles predicted by the standard model. The four lightest quark flavours, the up, down, strange and charm quarks, were well-established by the mid-1970's. The discovery in 1977 of the {Tau} resonances, a new family of massive hadrons, required the introduction of the fifth quark flavour. Experimental and theoretical studies have indicated that this quark also has a heavier partner, the top quark.
Baryons with Two Heavy Quarks as Solitons
Bander, Myron; Subbaraman, Anand
1994-01-01
Using the chiral soliton model and heavy quark symmetry we study baryons containing two heavy quarks. If there exists a stable (under strong interactions) meson consisting of two heavy quarks and two light ones, then we find that there always exists a state of this meson bound to a chiral soliton and to a chiral anti-soliton, corresponding to a two heavy quark baryon and a baryon containing two heavy anti-quarks and five light quarks, or a ``heptaquark".
Kurkela, Aleksi
2016-01-01
We generalize the state-of-the-art perturbative Equation of State of cold quark matter to nonzero temperatures, needed in the description of neutron star mergers and core collapse processes. The new result is accurate to order g^5 in the gauge coupling, and is based on a novel framework for dealing with the infrared sensitive soft field modes of the theory. The zero Matsubara mode sector is treated using a dimensionally reduced effective theory, while the soft non-zero modes are resummed using the Hard Thermal Loop approximation. This combination of known effective descriptions offers unprecedented access to small but nonzero temperatures, both in and out of beta equilibrium.
International Nuclear Information System (INIS)
This volume is a compilation of the papers presented at the September 1983 NATO ASI Conference on Quarks and Leptons. Subjects covered include: physics results of the UAl collaboration at the CERN proton-antiproton collider, charged current mixing and CP-violation, lattice quantum chromodynamics, lattice gauge theory with matter, left-right symmetric models of weak interactions, extensions of the standard model, supersymmetry in particle physics, quasi nambu-Goldstone fermions, cosmology and particle physics, low energy theorem for the Goldstino, superstrings, different formulations of N=1 supergravity and model building, and supersymmetric GUTS
International Nuclear Information System (INIS)
It is argued on theoretical and phenomenological grounds that confinement of quarks is intrinsically a many-body interaction. The Born-Oppenheimer approximation to the bag model is shown to give rise to a static potential energy that consists of a sum of two-body Coulomb terms and a many-body confining term. Following the success of this potential in heavy Q anti Q systems it is being applied to Q2 anti Q2. Preliminary calculations suggest that dimeson bound states with exotic flavor, such as bb anti s anti s, exist. 13 refs., 5 figs
Kurkela, Aleksi; Vuorinen, Aleksi
2016-07-22
We generalize the state-of-the-art perturbative equation of state of cold quark matter to nonzero temperatures, needed in the description of neutron star mergers and core collapse processes. The new result is accurate to O(g^{5}) in the gauge coupling, and is based on a novel framework for dealing with the infrared sensitive soft field modes of the theory. The zero Matsubara mode sector is treated via a dimensionally reduced effective theory, while the soft nonzero modes are resummed using the hard thermal loop approximation. This combination of known effective descriptions offers unprecedented access to small but nonzero temperatures, both in and out of beta equilibrium. PMID:27494468
Direct Top Quark Production at Hadron Colliders as a Probe of New Physics
Hosch, M.; Whisnant, K.; Young, B. -L.
1997-01-01
We examine the effect of an anomalous flavor changing chromomagnetic moment which allows direct top quark production (two partons combining into an unaccompanied single top quark in the s-channel) at hadron colliders. We consider both t-c-g and t-u-g couplings. We find that the anomalous charm quark coupling parameter $\\kappa_c / \\Lambda$ can be measured down to $.06 TeV^{-1}(.009 TeV^{-1}$) at the Tevatron with the Main Injector upgrade(LHC). The anomalous up quark coupling parameter $\\kappa...
Inclusive χc and b-quark production in bar pp collisions at √s =1.8 TeV
International Nuclear Information System (INIS)
We report the full reconstruction of χc mesons through the decay chain χc→J/ψ γ, J/ψ→μ+μ-, using data obtained at the Collider Detector at Fermilab in 2.6±0.2 pb-1 of bar pp collisions at √s =1.8 TeV. This exclusive χc sample is used to measure the χc-meson production cross section times branching fractions. We obtain σxB=3.2±0.4(stat)-1.1+1.2(syst) nb for χc mesons decaying to J/ψ with pT>6.0 GeV/c and pseudorapidity |η|Tb>8.5 GeV/c and |yb|<1
Top Quark Physics: Future Measurements
International Nuclear Information System (INIS)
We discuss the study of the top quark at future experiments and machines. Top's large mass makes it a unique probe of physics at the natural electroweak scale. We emphasize measurements of the top quark's mass, width, and couplings, as well as searches for rare or nonstandard decays, and discuss the complementary roles played by hadron and lepton colliders
Top quark physics: Future Measurements
International Nuclear Information System (INIS)
We discuss the study of the top quark at future experiments and machines. Top's large mass makes it a unique probe of physics at the natural electroweak scale. We emphasize measurements of the top quark's mass, width, and couplings, as well as searches for rare or nonstandard decays, and discuss the complementary roles played by hadron and lepton colliders
Neubert, Matthias(PRISMA Cluster of Excellence & Mainz Institut for Theoretical Physics, Johannes Gutenberg University, D-55099, Mainz, Germany)
1996-01-01
We give an introduction to the heavy-quark effective theory and the $1/m_Q$ expansion, which provide the modern framework for a systematic, model-independent description of the properties and decays of hadrons containing a heavy quark. We discuss the applications of these concepts to spectroscopy and to the weak decays of $B$ mesons.
Bag model of quark confinement
International Nuclear Information System (INIS)
The flavor and color models along with the bag confinement model for quarks are described together with a brief history of quark theory and experiment. The implications of these theories for the structure of the present elementary particles and hence that of all matter are given as well
Color superconductivity and quark stars
International Nuclear Information System (INIS)
The search for new phases of strange quark matter inside neutron stars has recently received a lot of attention since it has been shown that the attractive nature of the one gluon exchange interaction in QCD may produce a superconducting phase in quark matter. We study an extended version of the Chromodielectric model with a BCS quark pairing implemented, and analyze the superconducting color flavor locked phase. We show that the inclusion in the free energy density of a negative term of the diquark condensate ensures the stability of quark matter. We explore the implications of our results in the structure of compact quark stars and explicitly show that CFL stars can be absolutely stable and more compact than strange stars
Color superconductivity and quark stars
Energy Technology Data Exchange (ETDEWEB)
Malheiro, M. [Instituto Tecnologico de Aeronautica, CTA, 12-228-900, Sao Jose dos Campos (Brazil); Instituto de Fisica, Universidade Federal Fluminense, 24-210-320, Niteroi (Brazil); Linares, L.P. [Instituto de Fisica, Universidade Federal Fluminense, 24-210-320, Niteroi (Brazil); Fiolhais, M. [Departamento de Fisica, Centro de Fisica Computacional, Universidade de Coimbra, P-3004-516 Coimbra (Portugal); Taurines, A. [Department of Physics, University of Wales Swansea, Singleton Park, Swansea, SA2 8PP (United Kingdom)
2007-06-15
The search for new phases of strange quark matter inside neutron stars has recently received a lot of attention since it has been shown that the attractive nature of the one gluon exchange interaction in QCD may produce a superconducting phase in quark matter. We study an extended version of the Chromodielectric model with a BCS quark pairing implemented, and analyze the superconducting color flavor locked phase. We show that the inclusion in the free energy density of a negative term of the diquark condensate ensures the stability of quark matter. We explore the implications of our results in the structure of compact quark stars and explicitly show that CFL stars can be absolutely stable and more compact than strange stars.
Jet quenching and heavy quarks
Renk, Thorsten
2014-05-01
Jet quenching and more generally physics at high transverse momentum PT scales is a cornerstone of the heavy-ion physics program at both RHIC and LHC. In this work, the current understanding of jet quenching in terms of a QCD shower evolution being modified by the surrounding medium is reviewed along with the evidence for this picture from light parton high PT observables. Conceptually, the same QCD shower description should also be relevant for heavy quarks, but with several important modifications introduced by the quark masses. Thus especially in the limit of small jet energy over quark mass Ejet/mq, the relevant physics may be rather different from light quark jets, and several attempts to explain the observed phenomenology of heavy quarks at high PT are discussed here.
Jet quenching and heavy quarks
International Nuclear Information System (INIS)
Jet quenching and more generally physics at high transverse momentum PT scales is a cornerstone of the heavy-ion physics program at both RHIC and LHC. In this work, the current understanding of jet quenching in terms of a QCD shower evolution being modified by the surrounding medium is reviewed along with the evidence for this picture from light parton high PT observables. Conceptually, the same QCD shower description should also be relevant for heavy quarks, but with several important modifications introduced by the quark masses. Thus especially in the limit of small jet energy over quark mass Ejet/mq, the relevant physics may be rather different from light quark jets, and several attempts to explain the observed phenomenology of heavy quarks at high PT are discussed here
Investigation of the splitting of quark and gluon jets
Abreu, P; Adye, T; Adzic, P; Ajinenko, I; Alekseev, G D; Alemany, R; Allport, P P; Almehed, S; Amaldi, Ugo; Amato, S; Andersson, P; Andreazza, A; Antilogus, P; Apel, W D; Arnoud, Y; Åsman, B; Augustin, J E; Augustinus, A; Baillon, Paul; Bambade, P; Barão, F; Barbier, R; Bardin, Dimitri Yuri; Barker, G; Baroncelli, A; Bärring, O; Bates, M J; Battaglia, Marco; Baubillier, M; Becks, K H; Begalli, M; Beillière, P; Belokopytov, Yu A; Belous, K S; Benvenuti, Alberto C; Bérat, C; Berggren, M; Bertini, D; Bertrand, D; Besançon, M; Bianchi, F; Bigi, M; Bilenky, S M; Billoir, P; Bizouard, M A; Bloch, D; Bonesini, M; Bonivento, W; Boonekamp, M; Booth, P S L; Borgland, A W; Borisov, G; Bosio, C; Botner, O; Boudinov, E; Bouquet, B; Bourdarios, C; Bowcock, T J V; Bozovic, I; Bozzo, M; Branchini, P; Brand, K D; Brenke, T; Brenner, R A; Brown, R; Brückman, P; Brunet, J M; Bugge, L; Buran, T; Burgsmüller, T; Buschmann, P; Cabrera, S; Caccia, M; Calvi, M; Camacho-Rozas, A J; Camporesi, T; Canale, V; Canepa, M; Carena, F; Carroll, L; Caso, Carlo; Castillo-Gimenez, M V; Cattai, A; Cavallo, F R; Cerruti, C; Chabaud, V; Chapkin, M M; Charpentier, P; Chaussard, L; Checchia, P; Chelkov, G A; Chen, M; Chierici, R; Chliapnikov, P V; Chochula, P; Chorowicz, V; Chudoba, J; Collins, P; Colomer, M; Contri, R; Cortina, E; Cosme, G; Cossutti, F; Cowell, J H; Crawley, H B; Crennell, D J; Crosetti, G; Cuevas-Maestro, J; Czellar, S; D'Almagne, B; Damgaard, G; Dauncey, P D; Davenport, Martyn; Da Silva, W; Deghorain, A; Della Ricca, G; Delpierre, P A; Demaria, N; De Angelis, A; de Boer, Wim; De Brabandere, S; De Clercq, C; La Vaissière, C de; De Lotto, B; De Min, A; De Paula, L S; Dijkstra, H; Di Ciaccio, Lucia; Di Diodato, A; Djannati, A; Dolbeau, J; Doroba, K; Dracos, M; Drees, J; Drees, K A; Dris, M; Duperrin, A; Durand, J D; Edsall, D M; Ehret, R; Eigen, G; Ekelöf, T J C; Ekspong, Gösta; Ellert, M; Elsing, M; Engel, J P; Erzen, B; Espirito-Santo, M C; Falk, E; Fanourakis, G K; Fassouliotis, D; Fayot, J; Feindt, Michael; Fenyuk, A; Ferrari, P; Ferrer, A; Fichet, S; Firestone, A; Fischer, P A; Flagmeyer, U; Föth, H; Fokitis, E; Fontanelli, F; Formenti, F; Franek, B J; Frodesen, A G; Fulda-Quenzer, F; Fuster, J A; Galloni, A; Gamba, D; Gandelman, M; García, C; García, J; Gaspar, C; Gaspar, M; Gasparini, U; Gavillet, P; Gazis, E N; Gelé, D; Gerber, J P; Ghodbane, N; Glege, F; Gokieli, R; Golob, B; Gonçalves, P; González-Caballero, I; Gopal, Gian P; Gorn, L; Górski, M; Gracco, Valerio; Grahl, J; Graziani, E; Green, C; Grefrath, A; Gris, P; Grosdidier, G; Grzelak, K; Günther, M; Guy, J; Hahn, F; Hahn, S; Haider, S; Hajduk, Z; Hallgren, A; Hamacher, K; Harris, F J; Hedberg, V; Heising, S; Henriques, R P; Hernández, J J; Herquet, P; Herr, H; Hessing, T L; Heuser, J M; Higón, E; Holmgren, S O; Holt, P J; Holthuizen, D J; Hoorelbeke, S; Houlden, M A; Hrubec, Josef; Huet, K; Hultqvist, K; Jackson, J N; Jacobsson, R; Jalocha, P; Janik, R; Jarlskog, C; Jarlskog, G; Jarry, P; Jean-Marie, B; Johansson, E K; Jönsson, L B; Jönsson, P E; Joram, C; Juillot, P; Kapusta, F; Karafasoulis, K; Katsanevas, S; Katsoufis, E C; Keränen, R; Khokhlov, Yu A; Khomenko, B A; Khovanskii, N N; King, B J; Kjaer, N J; Klapp, O; Klein, H; Kluit, P M; Knoblauch, D; Kokkinias, P; Konoplyannikov, A K; Koratzinos, M; Korcyl, K; Kostyukhin, V; Kourkoumelis, C; Kuznetsov, O; Krammer, Manfred; Kreuter, C; Kronkvist, I J; Krumshtein, Z; Kubinec, P; Kucewicz, W; Kurvinen, K L; Lacasta, C; Lamsa, J; Lanceri, L; Lane, D W; Langefeld, P; Laugier, J P; Lauhakangas, R; Leder, Gerhard; Ledroit, F; Lefébure, V; Legan, C K; Leisos, A; Leitner, R; Lemonne, J; Lenzen, Georg; Lepeltier, V; Lesiak, T; Lethuillier, M; Libby, J; Liko, D; Lipniacka, A; Lippi, I; Lörstad, B; Loken, J G; Lopes, J H; López, J M; Loukas, D; Lutz, P; Lyons, L; MacNaughton, J N; Maehlum, G; Mahon, J R; Maio, A; Malek, A; Malmgren, T G M; Malychev, V; Mandl, F; Marco, J; Marco, R P; Maréchal, B; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Martínez-Rivero, C; Martínez-Vidal, F; Martí i García, S; Masik, J; Matorras, F; Matteuzzi, C; Matthiae, Giorgio; Mazzucato, F; Mazzucato, M; McCubbin, M L; McKay, R; McNulty, R; McPherson, G; Medbo, J; Meroni, C; Meyer, W T; Myagkov, A; Michelotto, M; Migliore, E; Mirabito, L; Mitaroff, Winfried A; Mjörnmark, U; Moa, T; Møller, R; Mönig, K; Monge, M R; Moreau, X; Morettini, P; Müller, H; Münich, K; Mulders, M; Mundim, L M; Murray, W J; Muryn, B; Myatt, Gerald; Myklebust, T; Naraghi, F; Navarria, Francesco Luigi; Navas, S; Nawrocki, K; Negri, P; Némécek, S; Neufeld, N; Neumann, W; Neumeister, N; Nicolaidou, R; Nielsen, B S; Nieuwenhuizen, M; Nikolaenko, V; Nikolenko, M; Niss, P; Nomerotski, A; Normand, Ainsley; Nygren, A; Oberschulte-Beckmann, W; Obraztsov, V F; Olshevskii, A G; Onofre, A; Orava, Risto; Orazi, G; Österberg, K; Ouraou, A; Paganini, P; Paganoni, M; Paiano, S; Pain, R; Paiva, R; Palka, H; Papadopoulou, T D; Papageorgiou, K; Pape, L; Parkes, C; Parodi, F; Parzefall, U; Passeri, A; Pegoraro, M; Peralta, L; Pernegger, H; Pernicka, Manfred; Perrotta, A; Petridou, C; Petrolini, A; Phillips, H T; Piana, G; Pierre, F; Pimenta, M; Piotto, E; Podobnik, T; Podobrin, O; Pol, M E; Polok, G; Poropat, P; Pozdnyakov, V; Privitera, P; Pukhaeva, N; Pullia, Antonio; Radojicic, D; Ragazzi, S; Rahmani, H; Ratoff, P N; Read, A L; Rebecchi, P; Redaelli, N G; Regler, Meinhard; Reid, D; Reinhardt, R; Renton, P B; Resvanis, L K; Richard, F; Rídky, J; Rinaudo, G; Røhne, O M; Romero, A; Ronchese, P; Rosenberg, E I; Rosinsky, P; Roudeau, Patrick; Rovelli, T; Ruhlmann-Kleider, V; Ruiz, A; Saarikko, H; Sacquin, Yu; Sadovskii, A; Sajot, G; Salt, J; Sampsonidis, D; Sannino, M; Schneider, H; Schwickerath, U; Schyns, M A E; Scuri, F; Seager, P; Sedykh, Yu; Segar, A M; Sekulin, R L; Shellard, R C; Sheridan, A; Silvestre, R; Simonetto, F; Sissakian, A N; Skaali, T B; Smadja, G; Smirnova, O G; Smith, G R; Sokolov, A; Solovyanov, O; Sopczak, André; Sosnowski, R; Souza-Santos, D; Spassoff, Tz; Spiriti, E; Sponholz, P; Squarcia, S; Stampfer, D; Stanescu, C; Stanic, S; Stapnes, Steinar; Stavitski, I; Stevenson, K; Stocchi, A; Strauss, J; Strub, R; Stugu, B; Szczekowski, M; Szeptycka, M; Tabarelli de Fatis, T; Tegenfeldt, F; Terranova, F; Thomas, J; Tilquin, A; Timmermans, J; Tkatchev, L G; Todorov, T; Todorova, S; Toet, D Z; Tomaradze, A G; Tomé, B; Tonazzo, A; Tortora, L; Tranströmer, G; Treille, D; Tristram, G; Trombini, A; Troncon, C; Tsirou, A L; Turluer, M L; Tyapkin, I A; Tyndel, M; Tzamarias, S; Überschär, B; Ullaland, O; Uvarov, V; Valenti, G; Vallazza, E; Van der Velde, C; van Apeldoorn, G W; van Dam, P; Van Doninck, W K; Van Eldik, J; Van Lysebetten, A; Van Vulpen, I B; Vassilopoulos, N; Vegni, G; Ventura, L; Venus, W A; Verbeure, F; Verlato, M; Vertogradov, L S; Verzi, V; Vilanova, D; Vincent, P; Vitale, L; Vodopyanov, A S; Vrba, V; Wahlen, H; Walck, C; Waldner, F; Weiser, C; Wetherell, Alan M; Wicke, D; Wickens, J H; Wielers, M; Wilkinson, G R; Williams, W S C; Winter, M; Witek, M; Wlodek, T; Wolf, G; Yi, J; Yushchenko, O P; Zaitsev, A; Zalewska-Bak, A; Zalewski, Piotr; Zavrtanik, D; Zevgolatakos, E; Zimin, N I; Zucchelli, G C; Zumerle, G
1998-01-01
The splitting processes in identified quark and gluon jets are investigated using longitudinal and transverse observables. The jets are selected from symmetric three-jet events measured in Z decays L with the {\\sc Delphi} detector in 1991-1994. Gluon jets are identified using heavy quark anti-tagging. Scaling violations in identified gluon jets are observed for the first time. The scale energy dependence of the gluon fragmentation function is found to be about two times larger than for the corresponding quark jets, consistent with the QCD expectation $C_A/C_F$. The primary splitting of gluons and quarks into subjets agrees with fragmentation models and, for specific regions of the jet resolution $y$, with NLLA calculations. The maximum of the ratio of the primary subjet splittings in quark and gluon jets is $2.77\\pm0.11\\pm0.10$. Due to non-perturbative effects, the data are below the expectation at small $y$. The transition from the perturbative to the non-perturbative domain appears at smaller $y$ for quark ...
Energy Technology Data Exchange (ETDEWEB)
Schramm, D.N. [Chicago Univ., IL (United States)]|[Fermi National Accelerator Lab., Batavia, IL (United States); Fields, B.; Thomas, D. [Chicago Univ., IL (United States)
1992-01-01
The possible implications of the quark-hadron transition for cosmology are explored. Possible surviving signatures are discussed. In particular, the possibility of generating a dark matter candidate such as strange nuggets or planetary mass black holes is noted. Much discussion is devoted to the possible role of the transition for cosmological nucleosynthesis. It is emphasized that even an optimized first order phase transition will not significantly alter the nucleosynthesis constraints on the cosmological baryon density nor on neutrino counting. However, it is noted that Be and B observations in old stars may eventually be able to be a signature of a cosmologically significant quark-hadron transition. It is pointed out that the critical point in this regard is whether the observed B/Be ratio can be produced by spallation processes or requires cosmological input. Spallation cannot produce a B/Be ratio below 7.6. A supporting signature would be Be and B ratios to oxygen that greatly exceed galactic values. At present, all data is still consistent with a spallagenic origin.
International Nuclear Information System (INIS)
The possible implications of the quark-hadron transition for cosmology are explored. Possible surviving signatures are discussed. In particular, the possibility of generating a dark matter candidate such as strange nuggets or planetary mass black holes is noted. Much discussion is devoted to the possible role of the transition for cosmological nucleosynthesis. It is emphasized that even an optimized first order phase transition will not significantly alter the nucleosynthesis constraints on the cosmological baryon density nor on neutrino counting. However, it is noted that Be and B observations in old stars may eventually be able to be a signature of a cosmologically significant quark-hadron transition. It is pointed out that the critical point in this regard is whether the observed B/Be ratio can be produced by spallation processes or requires cosmological input. Spallation cannot produce a B/Be ratio below 7.6. A supporting signature would be Be and B ratios to oxygen that greatly exceed galactic values. At present, all data is still consistent with a spallagenic origin
Quark mass density- and temperature- dependent model for bulk strange quark matter
al, Yun Zhang et.
2002-01-01
It is shown that the quark mass density-dependent model can not be used to explain the process of the quark deconfinement phase transition because the quark confinement is permanent in this model. A quark mass density- and temperature-dependent model in which the quark confinement is impermanent has been suggested. We argue that the vacuum energy density B is a function of temperature. The dynamical and thermodynamical properties of bulk strange quark matter for quark mass density- and temper...
Heavy quark fragmenting jet functions
International Nuclear Information System (INIS)
Heavy quark fragmenting jet functions describe the fragmentation of a parton into a jet containing a heavy quark, carrying a fraction of the jet momentum. They are two-scale objects, sensitive to the heavy quark mass, mQ, and to a jet resolution variable, τN. We discuss how cross sections for heavy flavor production at high transverse momentum can be expressed in terms of heavy quark fragmenting jet functions, and how the properties of these functions can be used to achieve a simultaneous resummation of logarithms of the jet resolution variable, and logarithms of the quark mass. We calculate the heavy quark fragmenting jet function GQQ at O(αs), and the gluon and light quark fragmenting jet functions into a heavy quark, GgQ and GlQ, at O(αs2). We verify that, in the limit in which the jet invariant mass is much larger than mQ, the logarithmic dependence of the fragmenting jet functions on the quark mass is reproduced by the heavy quark fragmentation functions. The fragmenting jet functions can thus be written as convolutions of the fragmentation functions with the matching coefficients Jij, which depend only on dynamics at the jet scale. We reproduce the known matching coefficients Jij at O(αs), and we obtain the expressions of the coefficients JgQ and JlQ at O(αs2). Our calculation provides all the perturbative ingredients for the simultaneous resummation of logarithms of mQ and τN
Quark Propagation in the Quark-Gluon Plasma
Li, Xiangdong; Shakin, C M; Sun, Qing; Li, Xiangdong; Li, Hu; Sun, Qing
2004-01-01
It has recently been suggested that the quark-gluon plasma formed in heavy-ion collisions behaves as a nearly ideal fluid. That behavior may be understood if the quark and antiquark mean-free- paths are very small in the system, leading to a "sticky molasses" description of the plasma, as advocated by the Stony Brook group. This behavior may be traced to the fact that there are relatively low-energy $q\\bar{q}$ resonance states in the plasma leading to very large scattering lengths for the quarks. These resonances have been found in lattice simulation of QCD using the maximum entropy method (MEM). We have used a chiral quark model, which provides a simple representation of effects due to instanton dynamics, to study the resonances obtained using the MEM scheme. In the present work we use our model to study the optical potential of a quark in the quark-gluon plasma and calculate the quark mean-free-path. Our results represent a specific example of the dynamics of the plasma as described by the Stony Brook group...
A chiral symmetric quark model without free quarks
International Nuclear Information System (INIS)
A chirally symmetric quark model is presented which contrary to the Nambu Jona-Lasinio (NJL) model does not lead to the presence of free quarks. In the model a non-local effective interaction is used as a schematic parameterization of the quark antiquark scattering kernel. The non-locality can be interpreted as phenomenologically taking into account an infinite number of elementary scattering processes, like the sum of all multi-gluon exchange processes in the particle-particle channel. The basic Lagrangian of the interaction shares all global internal symmetries with QCD. In particular in the limit of vanishing current quark masses it is chirally symmetric. Starting from the non-local scattering kernel the solution of the Dyson-Schwinger equation and the Bethe-Salpeter equation leads to a consistent description of the dressed quark propagators with the mesonsa s quark-antiquark states. Like in the NJL-model chiral symmetry is spontaneously broken. Because of the non-locality of the interaction, however, in our model the quarks do not acquire a constant constituent mass but a four momentum dependent selfenergy. (orig.)
S wave bottomonium states moving in a quark-gluon plasma from lattice NRQCD
Aarts, Gert; Kim, Seyong; Lombardo, Maria Paola; Oktay, Mehmet B; Ryan, Sinead M; Sinclair, D K; Skullerud, Jon-Ivar
2012-01-01
We extend our study of bottomonium spectral functions in the quark-gluon plasma to nonzero momentum. We use lattice QCD simulations with two flavours of light quark on highly anisotropic lattices and treat the bottom quark with nonrelativistic QCD (NRQCD). We focus on S wave (Upsilon and eta_b) channels and consider nonrelativistic velocities, v/c < 0.2. A comparison with predictions from effective field theory is made.
Determination of the quark coupling strength $|V_{ub}|$ using baryonic decays
Aaij, Roel; Adinolfi, Marco; Affolder, Anthony; Ajaltouni, Ziad; Akar, Simon; Albrecht, Johannes; Alessio, Federico; Alexander, Michael; Ali, Suvayu; Alkhazov, Georgy; Alvarez Cartelle, Paula; Alves Jr, Antonio Augusto; Amato, Sandra; Amerio, Silvia; Amhis, Yasmine; An, Liupan; Anderlini, Lucio; Anderson, Jonathan; Andreotti, Mirco; Andrews, Jason; Appleby, Robert; Aquines Gutierrez, Osvaldo; Archilli, Flavio; Artamonov, Alexander; Artuso, Marina; Aslanides, Elie; Auriemma, Giulio; Baalouch, Marouen; Bachmann, Sebastian; Back, John; Badalov, Alexey; Baesso, Clarissa; Baldini, Wander; Barlow, Roger; Barschel, Colin; Barsuk, Sergey; Barter, William; Batozskaya, Varvara; Battista, Vincenzo; Bay, Aurelio; Beaucourt, Leo; Beddow, John; Bedeschi, Franco; Bediaga, Ignacio; Belyaev, Ivan; Ben-Haim, Eli; Bencivenni, Giovanni; Benson, Sean; Benton, Jack; Berezhnoy, Alexander; Bernet, Roland; Bertolin, Alessandro; Bettler, Marc-Olivier; van Beuzekom, Martinus; Bien, Alexander; Bifani, Simone; Bird, Thomas; Bizzeti, Andrea; Blake, Thomas; Blanc, Frédéric; Blouw, Johan; Blusk, Steven; Bocci, Valerio; Bondar, Alexander; Bondar, Nikolay; Bonivento, Walter; Borghi, Silvia; Borsato, Martino; Bowcock, Themistocles; Bowen, Espen Eie; Bozzi, Concezio; Braun, Svende; Brett, David; Britsch, Markward; Britton, Thomas; Brodzicka, Jolanta; Brook, Nicholas; Bursche, Albert; Buytaert, Jan; Cadeddu, Sandro; Calabrese, Roberto; Calvi, Marta; Calvo Gomez, Miriam; Campana, Pierluigi; Campora Perez, Daniel; Capriotti, Lorenzo; Carbone, Angelo; Carboni, Giovanni; Cardinale, Roberta; Cardini, Alessandro; Carniti, Paolo; Carson, Laurence; Carvalho Akiba, Kazuyoshi; Casanova Mohr, Raimon; Casse, Gianluigi; Cassina, Lorenzo; Castillo Garcia, Lucia; Cattaneo, Marco; Cauet, Christophe; Cavallero, Giovanni; Cenci, Riccardo; Charles, Matthew; Charpentier, Philippe; Chefdeville, Maximilien; Chen, Shanzhen; Cheung, Shu-Faye; Chiapolini, Nicola; Chrzaszcz, Marcin; Cid Vidal, Xabier; Ciezarek, Gregory; Clarke, Peter; Clemencic, Marco; Cliff, Harry; Closier, Joel; Coco, Victor; Cogan, Julien; Cogneras, Eric; Cogoni, Violetta; Cojocariu, Lucian; Collazuol, Gianmaria; Collins, Paula; Comerma-Montells, Albert; Contu, Andrea; Cook, Andrew; Coombes, Matthew; Coquereau, Samuel; Corti, Gloria; Corvo, Marco; Counts, Ian; Couturier, Benjamin; Cowan, Greig; Craik, Daniel Charles; Crocombe, Andrew; Cruz Torres, Melissa Maria; Cunliffe, Samuel; Currie, Robert; D'Ambrosio, Carmelo; Dalseno, Jeremy; David, Pieter; Davis, Adam; De Bruyn, Kristof; De Capua, Stefano; De Cian, Michel; De Miranda, Jussara; De Paula, Leandro; De Silva, Weeraddana; De Simone, Patrizia; Dean, Cameron Thomas; Decamp, Daniel; Deckenhoff, Mirko; Del Buono, Luigi; Déléage, Nicolas; Derkach, Denis; Deschamps, Olivier; Dettori, Francesco; Dey, Biplab; Di Canto, Angelo; Di Ruscio, Francesco; Dijkstra, Hans; Donleavy, Stephanie; Dordei, Francesca; Dorigo, Mirco; Dosil Suárez, Alvaro; Dossett, David; Dovbnya, Anatoliy; Dreimanis, Karlis; Dufour, Laurent; Dujany, Giulio; Dupertuis, Frederic; Durante, Paolo; Dzhelyadin, Rustem; Dziurda, Agnieszka; Dzyuba, Alexey; Easo, Sajan; Egede, Ulrik; Egorychev, Victor; Eidelman, Semen; Eisenhardt, Stephan; Eitschberger, Ulrich; Ekelhof, Robert; Eklund, Lars; El Rifai, Ibrahim; Elsasser, Christian; Ely, Scott; Esen, Sevda; Evans, Hannah Mary; Evans, Timothy; Falabella, Antonio; Färber, Christian; Farinelli, Chiara; Farley, Nathanael; Farry, Stephen; Fay, Robert; Ferguson, Dianne; Fernandez Albor, Victor; Ferreira Rodrigues, Fernando; Ferro-Luzzi, Massimiliano; Filippov, Sergey; Fiore, Marco; Fiorini, Massimiliano; Firlej, Miroslaw; Fitzpatrick, Conor; Fiutowski, Tomasz; Fol, Philip; Fontana, Marianna; Fontanelli, Flavio; Forty, Roger; Francisco, Oscar; Frank, Markus; Frei, Christoph; Frosini, Maddalena; Fu, Jinlin; Furfaro, Emiliano; Gallas Torreira, Abraham; Galli, Domenico; Gallorini, Stefano; Gambetta, Silvia; Gandelman, Miriam; Gandini, Paolo; Gao, Yuanning; García Pardiñas, Julián; Garofoli, Justin; Garra Tico, Jordi; Garrido, Lluis; Gascon, David; Gaspar, Clara; Gastaldi, Ugo; Gauld, Rhorry; Gavardi, Laura; Gazzoni, Giulio; Geraci, Angelo; Gersabeck, Evelina; Gersabeck, Marco; Gershon, Timothy; Ghez, Philippe; Gianelle, Alessio; Gianì, Sebastiana; Gibson, Valerie; Giubega, Lavinia-Helena; Gligorov, Vladimir; Göbel, Carla; Golubkov, Dmitry; Golutvin, Andrey; Gomes, Alvaro; Gotti, Claudio; Grabalosa Gándara, Marc; Graciani Diaz, Ricardo; Granado Cardoso, Luis Alberto; Graugés, Eugeni; Graverini, Elena; Graziani, Giacomo; Grecu, Alexandru
2015-01-01
In the Standard Model of particle physics, the strength of the couplings of the $b$ quark to the $u$ and $c$ quarks, $|V_{ub}|$ and $|V_{cb}|$, are governed by the coupling of the quarks to the Higgs boson. Using data from the LHCb experiment at the Large Hadron Collider, the probability for the $\\Lambda^0_b$ baryon to decay into the $p \\mu^- \\overline{\
Strongly Coupled Quark Gluon Plasma (SCQGP)
Bannur, V M
2006-01-01
We propose that the reason for the non-ideal behavior seen in lattice simulation of quark gluon plasma (QGP) and relativistic heavy ion collisions (URHICs) experiments is that the QGP near T_c and above is strongly coupled plasma (SCP), i.e., strongly coupled quark gluon plasma (SCQGP). It is remarkable that the widely used equation of state (EoS) of SCP in QED (quantum electrodynamics) very nicely fits lattice results on all QGP systems, with proper modifications to include color degrees of freedom and running coupling constant. Results on pressure in pure gauge, 2-flavors and 3-flavors QGP, are all can be explained by treating QGP as SCQGP as demonstated here.Energy density and speed of sound are also presented for all three systems.
Study of the production of top quark pairs with ATLAS at the LHC - Measurement of the top quark mass
International Nuclear Information System (INIS)
Discovered in 1995 at Fermilab, top quark is the last quark discovered. The measurement of its properties allows physicists to test Standard Model predictions and to constraint Higgs boson mass. Due to its properties, the top quark is a privileged partner in the search for New Physics particles expected around TeV scale. This thesis, performed using the ATLAS detector at LHC, describes the different methods developed in order to measure precisely the top quark mass in its semileptonic decay. Two reconstruction methods are presented as well as a dedicated one based on Boosted Decision Trees. Its performances are quantified. The precise measurement of the top quark mass needs a deep understanding of the jet energy scale. This thesis presents two strategies to calibrate light and b jets to the parton scale. The performance of a kinematical fit applied to top mass measurement are presented. A precise measurement of the top quark mass is done using a calibrated scale to the parton level. The following values have been obtained with 1 fb-1 data: m(top)=(174.05±0.58(stat)±1.75(syst)) GeV2/c2 for the method based on topological vicinity and m(top)=(176.1±0.4(stat)±2.2(syst)) GeV2/c2 for the method based on Boosted Decision Tree
Quark model calculation of charmed baryon production by neutrinos
International Nuclear Information System (INIS)
We study the neutrino production of 25 low-lying charmed baryon resonances in the four flavour quark model. The mass difference of ordinary and charmed quarks is explicitly taken into account. The quark model is used to determine the spectrum of the charmed baryon resonances and the q2 = 0 values of the weak current transition matrix elements. These transition matrix elements are then continued to space-like q2-values by a generalized meson dominance ansatz for a set of suitably chosen invariant form factors. We find that the production of the L = 0 states C0, C1 and C1* is dominant, with the C0 produced most copiously. For L = 1, 2 the Jsup(P) = 3/2- 5/2+ charm states are dominant. We give differential cross sections, total cross sections and energy integrated total cross sections using experimental neutrino fluxes. (orig./BJ)
Light-quark, heavy-quark systems: An update
International Nuclear Information System (INIS)
The author reviews many of the recently developed applications of Heavy Quark Effective Theory techniques. After a brief update on Luke's theorm, he describes striking relations between heavy baryon form factors, and how to use them to estimate the accuracy of the extraction of |Bcb|. He discusses factorization and compares with experiment. An elementary presentation, with sample applications, of reparametrization invariance comes next. The final and most extensive chapter in this review deals with phenomenological lagrangians that incorporate heavy-quark spin-flavor as well as light quark chiral symmetries. He compiles many interesting results and discuss the validity of the calculations
Clustered Quark Matter Calculation for Strange Quark Matter
Na, Xuesen
2009-01-01
Motivated by the need for a solid state strange quark matter to better explain some observational phenomena, we discussed possibility of color singlet cluster formation in cold strange quark matter by a rough calculation following the excluded volume method proposed by Clark et al (1986) and adopted quark mass density dependent model with cubic scaling. It is found that 70% to 75% of volume and 80% to 90% of baryon number is in clusters at temperature from 10MeV to 50MeV and 1 to 10 times nuclear density.
ND^(*) and NB^(*) interactions in a chiral quark model
Yang, Dan; Zhang, Dan
2015-01-01
ND and ND^* interactions become a hot topic after the observation of new charmed hadrons \\Sigma_c(2800) and \\Lambda_c(2940)^+. In this letter, we have preliminary investigated S-wave ND and ND^* interactions with possible quantum numbers in the chiral SU(3) quark model and the extended chiral SU(3) quark model by solving the resonating group method equation. The numerical results show that the interactions between N and D or N and D^* are both attractive, which are mainly from \\sigma exchanges between light quarks. Further bound-state studies indicate the attractions are strong enough to form ND or ND^* molecules, except for (ND)_{J=3/2} and (ND^*)_{J=3/2} in the chiral SU(3) quark model. In consequence ND system with J=1/2 and ND^* system with J=3/2 in the extended SU(3) quark model could correspond to the observed \\Sigma_c(2800) and \\Lambda_c(2940)^+, respectively. Naturally, the same method can be applied to research NB and NB^* interactions, and similar conclusions obtained, i.e. NB and NB^* attractive fo...
A New Property of the Quark-Antiquark Potential in a Quark-Gluon Plasma
Benzahra, Sidi Cherkawi
2000-01-01
I consider the behavior of the quark-antiquark potential, called the Cornell Potential, in a quark-gluon plasma. Since mesons are no longer bound in the quark-gluon plasma, there might be a relationship between the string tension of the quark-antiquark potential, the mass of the quark, and the coupling constant.
Fragmentation processes in the quark combinatorics
International Nuclear Information System (INIS)
Fragmentation of one and two quarks into hadrons is considered in the framework of the quark combinatorics. In particle production processes the quark baryon number of 1/3 is shown to provide the probability of production of baryon states by the quark. The composition of baryon and meson states is discussed
Top Quark Properties Measurements in CMS
Yazgan, Efe; Collaboration, for the CMS
2016-01-01
Recent top quark properties measurements made with the CMS detector at the LHC are presented. The measurements summarized include spin correlation of top quark pairs, asymmetries, top quark mass, and the underlying event in top quark pair events. The results are compared to the standard model predictions and new physics models.
Top quark properties at ATLAS and CMS
Brock, Ian; The ATLAS collaboration
2016-01-01
Recent results from ATLAS and CMS connected to the properties of the top quark are presented. The talk concentrates on asymmetries connected with top-quark production and the measurement of spin correlations between the top quark and antiquark. A search for CP violation in top-quark-antiquark production is also discussed.
Baryons in the unquenched quark model
Bijker, R; Lopez-Ruiz, M A; Santopinto, E
2016-01-01
In this contribution, we present the unquenched quark model as an extension of the constituent quark model that includes the effects of sea quarks via a $^{3}P_{0}$ quark-antiquark pair-creation mechanism. Particular attention is paid to the spin and flavor content of the proton, magnetic moments and $\\beta$ decays of octet baryons.
Heavy baryons in the relativistic quark model
International Nuclear Information System (INIS)
In the framework of the relativistic quasipotential quark model the mass spectrum of baryons with two heavy quarks is calculated. The quasipotentials for interactions of two quarks and of a quark with a scalar and axial vector diquark are evaluated. The bound state masses of baryons with JP=1/2+, 3/2+ are computed. (orig.)
Mass renormalisation for improved staggered quarks
Hein, J.; Mason, Q.; Lepage, G. P.; Trottier, H.
2001-01-01
Improved staggered quark actions are designed to suppress flavour changing strong interactions. We discuss the perturbation theory for this type of actions and show the improvements to reduce the quark mass renormalisation compared to naive staggered quarks. The renormalisations are of similar size as for Wilson quarks.
Quarks and numerical simulation
International Nuclear Information System (INIS)
This work deals with the quantum chromodynamics and the theory of quarks's behaviour. The experimentation supports this theory but until now no computation have prove it. The resolution of the mathematic equations were far beyond the capability of human or the quickest computer of the seventies. A dedicated computer was built: the GF11. The mass of eight hadrons was computed in 91. In 95, a new particle was found by computation. The author explains the mathematical modeling of chromodynamics and the methods to solve it. It requires 1017 arithmetic operations. So specific computer is needed. GF11 uses 566 processors in parallel. New machines hundred of times more efficient will be needed to go further. That will be a new tool for theorician physicists. (O.M.). 9 refs., 2 figs., 1 tab
International Nuclear Information System (INIS)
An approximate model is proposed for a system of three Schroedinger particles of equal masses, interacting mutually through a universal two-body potential. They are assumed to form during their motion a (generally) varying equilateral triangle corresponding to Lagrange's exact triangle solution of the classical three-body problem. The resulting wave equation is formally a two-body Schroedinger equation (in the centre-of-mass frame). This is applied to three constituent quarks in the nucleon. The present model, called ''Lagrange triangle of Schroedinger particles'', may be considered as a non-relativistic approximation to the much more complicated ''Lagrange triangle of Dirac particles'' constructed by the author a decade ago. (author)
Melting hadrons, boiling quarks
Energy Technology Data Exchange (ETDEWEB)
Rafelski, Johann [CERN-PH/TH, Geneva 23 (Switzerland); The University of Arizona, Department of Physics, Tucson, Arizona (United States)
2015-09-15
In the context of the Hagedorn temperature half-centenary I describe our understanding of the hot phases of hadronic matter both below and above the Hagedorn temperature. The first part of the review addresses many frequently posed questions about properties of hadronic matter in different phases, phase transition and the exploration of quark-gluon plasma (QGP). The historical context of the discovery of QGP is shown and the role of strangeness and strange antibaryon signature of QGP illustrated. In the second part I discuss the corresponding theoretical ideas and show how experimental results can be used to describe the properties of QGP at hadronization. The material of this review is complemented by two early and unpublished reports containing the prediction of the different forms of hadron matter, and of the formation of QGP in relativistic heavy ion collisions, including the discussion of strangeness, and in particular strange antibaryon signature of QGP. (orig.)
Melting Hadrons, Boiling Quarks
Rafelski, Johann
2015-01-01
In the context of the Hagedorn temperature half-centenary I describe our understanding of the hot phases of hadronic matter both below and above the Hagedorn temperature. The first part of the review addresses many frequently posed questions about properties of hadronic matter in different phases, phase transition and the exploration of quark-gluon plasma (QGP). The historical context of the discovery of QGP is shown and the role of strangeness and strange antibaryon signature of QGP illustrated. In the second part I discuss the corresponding theoretical ideas and show how experimental results can be used to describe the properties of QGP at hadronization. Finally in two appendices I present previously unpublished reports describing the early prediction of the different forms of hadron matter and of the formation of QGP in relativistic heavy ion collisions, including the initial prediction of strangeness and in particular strange antibaryon signature of QGP.
Continuum estimate of the heavy quark momentum diffusion coefficient κ
International Nuclear Information System (INIS)
Among quantities playing a central role in the theoretical interpretation of heavy ion collision experiments at RHIC and LHC are so-called transport coefficients. Out of those heavy quark diffusion coefficients play an important role e.g. for the analysis of the quenching of jets containing c or b quarks (D or B mesons) as observed at RHIC and LHC [1]. We report on a lattice investigation of heavy quark momentum diffusion within pure SU(3) plasma above the deconfinement transition with the quarks treated to leading order in the heavy mass expansion. We measure the relevant “colour-electric” Euclidean correlator and based on several lattice spacings perform the continuum extrapolation. This extends our previous studies [2,3] progressing towards a removal of lattice artifacts and a physical interpretation of the results. We find that the correlation function clearly exceeds its perturbative counterpart which suggests that at temperatures just above the critical one, non-perturbative interactions felt by the heavy quarks are stronger than within the weak-coupling expansion. Using an Ansatz for the spectral function which includes NNLO perturbative contributions we were able to determine, for the first time, a continuum estimate for the heavy quark momentum diffusion coefficient
Weak interaction of leptons and quarks in the quaternion model
Energy Technology Data Exchange (ETDEWEB)
Chkareuli, Dzh.L. (AN Gruzinskoj SSR, Tbilisi. Inst. Fiziki)
1981-01-01
A gauge theory of spin 0, 1/2 and 1 quaternionic fields is built in order to obtain a unified description of the weak and electromagnetic interaction of quarks and leptons. The quaternionic field is associated with an ''electroweak'' charge whose components from the SU(2)xU(1) algebra, similarly to that the complex field is associated with the presence of the electric charge in the theory. The theory predicts at least eight quarks (leptons) in a form of pairs of quartets of ''light'' and ''heavy'' particles and involves not only Higgs neutral scalar h/sup 0/ but as well a complex doublet of scalars GIM structure is naturally realized in the quark quartets. All Glashow-Weinberg quark flavour conservation conditions are satisfied. In the sector of ''light'' quarks u, d, s, c CP is violated in the vertices corresponding to the interaction between the charged bosons H/sup + -/ and scalar quark current. An additional left-right symmetry of Yukawa potential makes it possible to fit the experimental values of Cabibbo angle.
Observation of the top quark with the DO detector
Energy Technology Data Exchange (ETDEWEB)
Hadley, N.J. [Univ. of Maryland, College Park, MD (United States)
1997-01-01
The DO Collaboration reports on the observation of the top quark in p{bar p} collisions at {radical}s = 1.8 TeV at the Fermilab Tevatron. We measure the top quark mass to be 199{sub -21}{sup -19}(stat){sub -21}{sup +14}(syst.) GeV/c{sup 2} and its production cross section to be 6.4 {+-}2.2 pb. Our result is based on approximately 50 pb{sup -1} of data. We observe 17 events with an expected background of 3.8 {+-} 0.6 events. The probability of an upward fluctuation of the background to produce the observed signal is 2 x 10{sup -6} (equivalent to 4.6 standard deviations). The kinematic properties of the events are consistent with top quark decay, and the distribution of events across the seven decay channels is consistent with the Standard Model top quark branching fractions. We describe the analysis that led to the observation of the top quark as well as the properties of the top quark events.
Energy Technology Data Exchange (ETDEWEB)
Moed, Shulamit; /Harvard U.
2010-01-01
The large data samples of top quark candidate events collected at the Tevatron CDF II experiment allow for a variety of measurements to analyze the production of the top quark. This article discusses recent results of top quark production at CDF presented at the SUSY09 conference, including updates to the top pair production cross section, forward-backward asymmetry in t{bar t} production, single top search, search for top resonances and a search for heavy top. The discussed measurements utilize up to 3.2 fb{sup -1} of integrated luminosity collected at CDF.
Quark Virtuality and QCD Vacuum Condensates
Institute of Scientific and Technical Information of China (English)
ZHOU Li-Juan; MA Wei-Xing
2004-01-01
@@ Based on the Dyson-Schwinger equations (DSEs) in the ‘rainbow' approximation, we investigate the quark virtuality in the vacuum state and quantum-chromodynamics (QCD) vacuum condensates. In particular, we calculate the local quark vacuum condensate and quark-gluon mixed condensates, and then the virtuality of quark. The calculated quark virtualities are λ2u,d = 0.7 GeV2 for u, d quarks, and 2s 1.6 GeV2 for s quark.Our theoretical predictions are consistent with empirical values used in QCD sum rules, and also fit to lattice QCD predictions.
Top quark studies at hadron colliders
Energy Technology Data Exchange (ETDEWEB)
Sinervo, P.K. [Univ. of Toronto, Ontario (Canada)
1997-01-01
The techniques used to study top quarks at hadron colliders are presented. The analyses that discovered the top quark are described, with emphasis on the techniques used to tag b quark jets in candidate events. The most recent measurements of top quark properties by the CDF and DO Collaborations are reviewed, including the top quark cross section, mass, branching fractions, and production properties. Future top quark studies at hadron colliders are discussed, and predictions for event yields and uncertainties in the measurements of top quark properties are presented.
Energy Technology Data Exchange (ETDEWEB)
Wicke, Daniel; /Wuppertal U., Dept. Math.
2009-08-01
The aim of particle physics is the understanding of elementary particles and their interactions. The current theory of elementary particle physics, the Standard Model, contains twelve different types of fermions which (neglecting gravity) interact through the gauge bosons of three forces. In addition a scalar particle, the Higgs boson, is needed for theoretical consistency. These few building blocks explain all experimental results found in the context of particle physics, so far. Nevertheless, it is believed that the Standard Model is only an approximation to a more complete theory. First of all the fourth known force, gravity, has withstood all attempts to be included until now. Furthermore, the Standard Model describes several features of the elementary particles like the existence of three families of fermions or the quantisation of charges, but does not explain these properties from underlying principles. Finally, the lightness of the Higgs boson needed to explain the symmetry breaking is difficult to maintain in the presence of expected corrections from gravity at high scales. This is the so called hierarchy problem. In addition astrophysical results indicate that the universe consists only to a very small fraction of matter described by the Standard Model. Large fractions of dark energy and dark matter are needed to describe the observations. Both do not have any correspondence in the Standard Model. Also the very small asymmetry between matter and anti-matter that results in the observed universe built of matter (and not of anti-matter) cannot be explained until now. It is thus an important task of experimental particle physics to test the predictions of the Standard Model to the best possible accuracy and to search for deviations pointing to necessary extensions or modifications of our current theoretical understanding. The top quark was predicted to exist by the Standard Model as the partner of the bottom quark. It was first observed in 1995 by the
Nuclear effects on valence quark distributions and sea quark distributions
International Nuclear Information System (INIS)
A method is presented to get nuclear effect functions RvA(xt) and Rsa(xt) on valence quark distributions and sea quark distributions from the data of 1-A DIS process and nuclear Drell-Yan process. Both the functions may be used to test the theoretical models explaining the nuclear effects. As a example, RvFe(xt) and RsFe(xt) of the iron nucleus were obtained by this method
Non-Fermi Liquid Behavior Induced by Resonant Diquark-pair Scattering in Heated Quark Matter
Kitazawa, M; Nemoto, Y; Kitazawa, Masakiyo; Kunihiro, Teiji; Nemoto, Yukio
2005-01-01
We show how the quasiparticle picture of quarks changes near but above the critical temperature T_c of the color-superconducting phase transition in the heated quark matter. We demonstrate that a non-Fermi liquid behavior of the matter develops drastically when the diquark coupling constant is increased owing to the coupling of the quark with the pairing soft mode: We clarify that the depression and eventually the appearance of a gap structure in the spectral function as well as the anomalous quark dispersion relation of the quark can be understood in terms of the resonant scattering between the incident quark and a particle near the Fermi surface to make the pairing soft mode.
Screening of heavy quarks and hadrons at finite temperature and density
Energy Technology Data Exchange (ETDEWEB)
Doering, M.
2006-09-22
Heavy quarks and hadrons placed in a strongly interacting thermal and baryon chemical quantum field are screened by the medium. I calculate the free energies of heavy quarks and anti-quarks and hadron correlation functions on a 16{sup 3} x 4 lattice in 2-flavour QCD with a bare quark mass of m/T=0.4. The dependence on the interparticle distance determines the screening masses as a function of temperature and density. The Taylor expansion method is used for the baryon chemical potential. The heavy quark screening masses turn out to be in good agreement with perturbation theory for temperatures T>2T{sub c}. The hadron screening masses are consistent with the free quark propagation in the large temperature regime. (orig.)
Quenched Charmed Meson Spectra Using Tadpole Improved Quark Action on Anisotropic Lattices
Institute of Scientific and Technical Information of China (English)
LIU Liu-Ming; SU Shi-Quan; LI Xin; LIU Chuan
2005-01-01
@@ Charmed meson charmonium spectra are studied with improved quark actions on anisotropic lattices. We measured the pseudo-scalar and vector meson dispersion relations for four lowest lattice momentum modes with quark mass values ranging from the strange quark to charm quark with three different values of gauge coupling β and four different values of bare speed of light v. With the bare speed of light parameter v tuned in a mass-dependent way, we study the mass spectra of D, Ds, ηc, D*, Ds* and J/ψ mesons. The results extrapolated to the continuum limit are compared with the experiment, and a qualitative agreement is found.
Recent PQCD calculations of heavy quark production
Vitev, I
2006-01-01
We summarize the results of a recent study of heavy quark production and attenuation in cold nuclear matter. In p+p collisions, we investigate the relative contribution of partonic sub-processes to $D$ meson production and $D$ meson-triggered inclusive di-hadrons to lowest order in perturbative QCD. While gluon fusion dominates the creation of large angle $D\\bar{D}$ pairs, charm on light parton scattering determines the yield of single inclusive $D$ mesons. The distinctly different non-perturbative fragmentation of $c$ quarks into $D$ mesons versus the fragmentation of quarks and gluons into light hadrons results in a strong transverse momentum dependence of anticharm content of the away-side charm-triggered jet. In p+A reactions, we calculate and resum the coherent nuclear-enhanced power corrections from the final-state partonic scattering in the medium. We find that single and double inclusive open charm production can be suppressed as much as the yield of neutral pions from dynamical high-twist shadowing. ...
Quark Orbital Angular Momentum in the Baryon
Song, Xiaotong
2000-01-01
Analytical and numerical results, for the orbital and spin content carried by different quark flavors in the baryons, are given in the chiral quark model with symmetry breaking. The reduction of the quark spin, due to the spin dilution in the chiral splitting processes, is transferred into the orbital motion of quarks and antiquarks. The orbital angular momentum for each quark flavor in the proton as a function of the partition factor $\\kappa$ and the chiral splitting probability $a$ is shown...
Asymmetries of quark sea in nucleon
Dahiya Harleen
2014-01-01
The effects of “quark sea” in determining the flavor structure of the octet baryons have been investigated in the chiral constituent quark model. The chiral constituent quark model is able to qualitatively generate the requisite amount of quark sea and is also known to provide a satisfactory explanation of the proton spin and related issues in the nonperturbative regime. The phenomenological implications of the quark sea asymmetries in the nucleon have been investigated to understand the impo...
Harmonic quarks: properties and some applications
Teplov, Oleg A.
2003-01-01
In this work the investigation of hadronic structures with the help of the harmonic quarks is prolonged. The harmonic quark model is good at describing the meson structures and the baryon excitations to resonances, in particular delta(1232). Harmonic quark reactions form the structure of the baryon resonances. Presumed quark structures of the mesons eta(548), omega(772), a(980) and f(980) are given. It became clear that the some hadronic structures contain the filled quark shells. The kinetic...
Hadron formation from interaction among quarks
International Nuclear Information System (INIS)
This paper deals with the hadronization process of quark system. A phenomenological potential is introduced to describe the interaction between a quark pair. The potential depends on the color charge of those quarks and their relative distances. Those quarks move according to classical equations of motion. Due to the color interaction, coloring quarks are separated to form color neutral clusters which are supposed to be the hadrons. (author)
Heavy quarks and CP: Moriond 1985
International Nuclear Information System (INIS)
The presentations at the Fifth Moriond Workshop on Heavy Quarks, Flavor Mixing, and CP Violation (La Plagne, France, January 13-19, 1985) are summarized. The following topics are reviewed. What's New (beyond the top, top quarks, bottom quarks, charm quarks, strange quarks, and others); why is all this being done (strong interactions and hadron structure, and electroweak properties); and what next (facilities and can one see CP violation in the B-anti B system). 64 refs., 10 figs
Structure of Nonlocal Vacuum Condensate of Quarks
Institute of Scientific and Technical Information of China (English)
周丽娟; 马维兴
2003-01-01
The Dyson-Schwinger formalism is used to derive a fully dressed quark propagator. By use of the derived form of the quark propagator, the structure of non-local quark vacuum condensate is studied, and the values of local quark vacuum condensate as well as quark gluon mixed condensate are calculated. The theoretical predictions are in good agreement with the empirical one used commonly in the literature.
International Nuclear Information System (INIS)
Understanding the nucleon structure is currently one of the main challenges encountered in nuclear physics. The present work represents a contribution to the study of the nucleon structure and deals, in particular, with the study of the role of strange quarks in the nucleon. The latter can be investigated by determining the strange quark distribution in the nucleon as well as the contribution of the spins of strange quarks to the nucleon spin. This work first presents a measurement of the nucleon spin performed via Deeply Inelastic Scattering (DIS) of a muon beam off polarized proton and deuterium targets. The result is found to be strongly dependent on the quark fragmentation functions into hadrons (FFs), which define the probability that a quark of a given flavour fragments into a final state hadron. The FFs are poorly known, in particular, the FF of strange quark into kaons, which play an important role in the determination of the nucleon spin. In deep inelastic scattering process, the access to the FFs is provided by the hadron multiplicities which, in turn, define the average number of hadrons produced per DIS event. Pion and kaon multiplicities have been extracted versus different kinematic variables, using DIS data collected by deeply inelastic scattering of a 160 GeV/c muons off a deuterium target. A first Leading Order (LO) extraction of the fragmentation functions has then been performed using the measured pion and kaon multiplicities. (author)
Quark Model and multiquark system
da Silva, Cristiane Oldoni
2010-01-01
The discovery of many particles, especially in the 50's, when the firsts accelerators appeared, caused the searching for a model that would describe in a simple form the whole of known particles. The Quark Model, based in the mathematical structures of group theory, provided in the beginning of the 60's a simplified description of hadronic matter already known, proposing that three particles, called quarks, would originate all the observed hadrons. This model was able to preview the existence of particles that were later detected, confirming its consistency. Extensions of the Quark Model were made in the beginning of the 70's, focusing in describing observed particles that were excited states of the fundamental particles and others that presented new quantum numbers (flavors). Recently, exotic states as tetraquarks and pentaquarks types, also called multiquarks systems, previewed by the model, were observed, what renewed the interest in the way as quarks are confined inside the hadrons. In this article we pre...
Dumé, Belle
2003-01-01
"Physicists working at the Relativistic Heavy Ion Collider (RHIC) at the Brookhaven National Laboratory in the US say that they have come closer than ever before to creating a quark-gluon plasma" (0.5 page)
Weak interactions of heavy quarks
International Nuclear Information System (INIS)
The status of our knowledhe about weak interactions of heavy quarks is reviewed within the framework of the Standard Theory. Several approaches to connect the basic Lagrangian to experimental measurements are discussed. (Author)
Baryon mapping of quark systems
Sambataro, M
1995-01-01
We discuss a mapping procedure from a space of colorless three-quark clusters into a space of elementary baryons and illustrate it in the context of a three-color extension of the Lipkin model recently developed. Special attention is addressed to the problem of the formation of unphysical states in the mapped space. A correspondence is established between quark and baryon spaces and the baryon image of a generic quark operator is defined both in its Hermitian and non-Hermitian forms. Its spectrum (identical in the two cases) is found to consist of a physical part containing the same eigenvalues of the quark operator in the cluster space and an unphysical part consisting only of zero eigenvalues. A physical subspace of the baryon space is also defined where the latter eigenvalues are suppressed. The procedure discussed is quite general and applications of it can be thought also in the correspondence between systems of 2n fermions and n bosons.
Kong, Kyoungchul; Park, Myeonghun
2014-01-01
We suggest top quark decays as a venue to search for light dark force carriers. Top quark is the heaviest particle in the standard model whose decays are relatively poorly measured, allowing sufficient room for new decay modes from new physics. A very light (GeV scale) dark gauge boson (Z') is a recently highlighted hypothetical particle that can address some astrophysical anomalies as well as the 3.6 sigma deviation in the muon g-2 measurement. We present and study a possible scenario that top quark decays as t -> b W + Z's. This is the same as the dominant top quark decay (t -> b W) accompanied by one or multiple dark force carriers. The Z' can be easily boosted, and it can decay into highly collimated leptons (lepton-jet) with large branching ratio. We discuss the implications for the Large Hadron Collider experiments including the analysis based on the lepton-jets.
Solid Bare Strange Quark Stars
Xu, R X
2003-01-01
The reason, we need three terms of `strange', `bare', and `solid' before quark stars, is presented concisely though some fundamental issues are not certain. Observations favoring these stars are introduced.
Current mass dependence of the quark condensate and the constituent quark mass
Musakhanov, M.
2001-01-01
We discuss the current mass dependence of the basic quantities of the quark models -- constituent quark mass M and quark condensate i. The framework of the consideration is QCD instanton vacuum model.
Measurement of Strange Quark Contributions to the Nucleon's Form Factors at Q^2=0.230 (GeV/c)^2
Collaboration, A.; Maas, F. E.; P. Achenbach(Mainz U., Inst. Phys); Aulenbacher, K.; Baunack, S.; Capozza, L.; Diefenbach, J.; Grimm, K.; Imai, Y.; Hammel, T.; Harrach, D. v.; Kabuss, E. M.; Kothe, R.; Lee, J.H.; Lorente, A.
2004-01-01
We report on a measurement of the parity-violating asymmetry in the scattering of longitudinally polarized electrons on unpolarized protons at a $Q^2$ of 0.230 (GeV/c)^2 and a scattering angle of \\theta_e = 30^o - 40^o. Using a large acceptance fast PbF_2 calorimeter with a solid angle of \\Delta\\Omega = 0.62 sr the A4 experiment is the first parity violation experiment to count individual scattering events. The measured asymmetry is A_{phys} =(-5.44 +- 0.54_{stat} +- 0.27_{\\rm sys}) 10^{-6}. ...
Unexpected manifestation of quark condensation
Energy Technology Data Exchange (ETDEWEB)
Zinovjev, G. M., E-mail: Gennady.Zinovjev@cern.ch [National Academy of Sciences of Ukraine, Bogolyubov Institute for Theoretical Physics (Ukraine); Molodtsov, S. V. [Joint Institute for Nuclear Research (Russian Federation)
2015-05-15
A comparative analysis of some quark ensembles governed by a four-fermion interaction is performed. Arguments in support of the statement that the presence of a gas-liquid phase transition is a feature peculiar to them are adduced. The instability of small quark droplets is discussed and is attributed to the formation of a chiral soliton. The stability of baryon matter is due to a mixed phase of the vacuum and baryon matter.
Nucleon Resonances and Quark Structure
Londergan, J T
2009-01-01
A pedagogical review of the past 50 years of study of resonances, leading to our understanding of the quark content of baryons and mesons. The level of this review is intended for undergraduates or first-year graduate students. Topics covered include: the quark structure of the proton as revealed through deep inelastic scattering; structure functions and what they reveal about proton structure; and prospects for further studies with new and upgraded facilities, particularly a proposed electron-ion collider.
Pourquoi les quarks restent invisibles
Gross, David J
2005-01-01
At the beginning of the seventies, physicists discovered a new scale in the matter structure. Protons and neutrons, components of the atomic nucleus, seemed to be constituted by even more elementar particles: the quarks. But while they seemed to move freely inside the protons, it was impossible to isolate one of these quarks. The Nobel Prize for physics rewarded the explanation of this phenomenon (3 pages)
Kühn, J. H.
1993-01-01
The status of top quark searches will be briefly reviewed. Theoretical predictions for the top quark decay rate are presented including QCD and electroweak radiative corrections. The possibilities for quarkonium searches at an hadron collider will be discussed. The perspectives for top production at an electron positron collider will be described in detail with emphasis on the behavior of the cross section and decay distribution in the threshold region.
Current and constituent quark masses
International Nuclear Information System (INIS)
It is shown how the current quark mass, engendered by the electroweak sector, gives rise to a constituent quark mass, via the Dyson-Schwinger equations. The chiral symmetry breaking phenomenon on massless QCD is thereby seen to have an implementable generalization to the situation in which the strong bare mass is non-zero. A consistent renormalization is carried out for an arbitrary covariant gauge. (author). 16 refs
Roulette wheels and quark confinement
International Nuclear Information System (INIS)
Studies of four dimensional space-time crystals with gauge field degrees of freedom are reviewed. Such studies are shown to yield strong numerical evidence that a non-Abelian gauge theory of the nuclear interactions can simultaneously display the phenomena of both asymptotic freedom, i.e. weak quark interactions at short distance and also imprisonment of quarks into the physical hadrons. (U.K.)
Mesons in relativistic quark model
International Nuclear Information System (INIS)
In the relativistic quark model formulated in the infinite momentum frame a self-consistent description has been obtained for a pion, ω- and ρ-mesons, K- and K*-mesons. The role of the relativistic effects in the description of radiative, leptonic and semileptonic decays of heavy quarkonia is studied. The relativistic effects are shown to lead to noticeable suppression of the ψ → ηcγ decay width predicted in nonrelativistic approximation; however the discrepancy with the experimental data still remains. Predictions are obtained for amplitudes of D → μν, Ds → μν, B → μν, D → πeν and D → Keν decays. The relativistic effects are shown to lead to strong supperssion of coupling constants of D → μν, Ds → μν, B → μν decays. The prediction obtained for the coupling constant FD = 230-270 MeV is close to the boundary of available experimental restriction. 46 refs.; 2 figs.; 5 tabs
Polarization in heavy quark decays
International Nuclear Information System (INIS)
In this thesis I concentrate on the angular correlations in top quark decays and their next.to.leading order (NLO) QCD corrections. I also discuss the leading.order (LO) angular correlations in unpolarized and polarized hyperon decays. In the first part of the thesis I calculate the angular correlation between the top quark spin and the momentum of decay products in the rest frame decay of a polarized top quark into a charged Higgs boson and a bottom quark in Two-Higgs-Doublet-Models: t(↑) → b + H+. I provide closed form formulae for the O(αs) radiative corrections to the unpolarized and the polar correlation functions for mb≠0 and mb=0. In the second part I concentrate on the semileptonic rest frame decay of a polarized top quark into a bottom quark and a lepton pair: t(↑)→Xb+l++νl. I present closed form expressions for the O(αs) radiative corrections to the unpolarized part and the polar and azimuthal correlations for mb≠0 and mb=0. In the last part I turn to the angular distribution in semileptonic hyperon decays. Using the helicity method I derive complete formulas for the leading order joint angular decay distributions occurring in semileptonic hyperon decays including lepton mass and polarization effects. (orig.)
Unquenched QCD with Light Quarks
Duncan, A; Yoo, J
2003-01-01
We present recent results in unquenched lattice QCD with two degenerate light sea quarks using the truncated determinant approximation (TDA). In the TDA the infrared modes contributing to the quark determinant are computed exactly up to some cutoff in quark off-shellness (typically 2$\\Lambda_{QCD}$). This approach allows simulations to be performed at much lighter quark masses than possible with conventional hybrid MonteCarlo techniques. Results for the static energy and topological charge distributions are presented using a large ensemble generated on very coarse (6$^4$) but physically large lattices. Preliminary results are also reported for the static energy and meson spectrum on 10$^3$x20 lattices (lattice scale $a^{-1}$=1.15 GeV) at quark masses corresponding to pions of mass $\\leq$ 200 MeV. Using multiboson simulation to compute the ultraviolet part of the quark determinant the TDA approach becomes an exact with essentially no increase in computational effort. Some preliminary results using this fully u...
Unquenched QCD with light quarks
International Nuclear Information System (INIS)
We present recent results in unquenched lattice QCD with two degenerate light sea quarks using the truncated determinant approximation (TDA). In the TDA the infrared modes contributing to the quark determinant are computed exactly up to some cutoff in quark off-shellness (typically 2ΛQCD). This approach allows simulations to be performed at much lighter quark masses than possible with conventional hybrid Monte Carlo techniques. Results for the static energy and topological charge distributions are presented using a large ensemble generated on very coarse (64) but physically large lattices. Preliminary results are also reported for the static energy and meson spectrum on 103x20 lattices (lattice scale a-1=1.15 GeV) at quark masses corresponding to pions of mass ≤200 MeV. Using multiboson simulation to compute the ultraviolet part of the quark determinant the TDA approach becomes an exact algorithm with essentially no increase in computational effort. Some preliminary results using this fully unquenched algorithm are presented
Search for Strange Quark Matter Produced in Relativistic Heavy Ion Collisions
Collaboration, T. A. Armstrong et al. The E864
2000-01-01
We present the final results from Experiment 864 of a search for charged and neutral strange quark matter produced in interactions of 11.5 GeV/c per nucleon Au beams with Pt or Pb targets. Searches were made for strange quark matter with A>4. Approximately 30 billion 10% most central collisions were sampled and no strangelet states with A
Comparison of gluon flux-tube distributions for quark-diquark and quark-antiquark hadrons
Bissey, F.; Signal, A. I.; Leinweber, D. B.
2009-01-01
The distribution of gluon fields in hadrons is of fundamental interest in QCD. Using lattice QCD we have observed the formation of gluon flux tubes within 3 quark (baryon) and quark plus antiquark (meson) systems for a wide variety of spatial distributions of the color sources. In particular we have investigated three quark configurations where two of the quarks are close together and the third quark is some distance away, which approximates a quark plus diquark string. We find that the strin...
Strange quark matter in a chiral SU(3) quark mean field model
Wang, P.; Lyubovitskij, V. E.; Gutsche, Th.; Faessler, Amand
2002-01-01
We apply the chiral SU(3) quark mean field model to investigate strange quark matter. The stability of strange quark matter with different strangeness fraction is studied. The interaction between quarks and vector mesons destabilizes the strange quark matter. If the strength of the vector coupling is the same as in hadronic matter, strangelets can not be formed. For the case of beta equilibrium, there is no strange quark matter which can be stable against hadron emission even without vector m...
T-odd quark-gluon-quark correlation function in the diquark model
Lu, Zhun; Schmidt, Ivan
2012-01-01
We study the transverse momentum dependent quark-gluon-quark correlation function. Using a spectator diquark model, we calculate the eight time-reversal-odd interaction-dependent twist-3 quark distributions appearing in the decomposition of the transverse momentum dependent quark-gluon-quark correlator. In order to obtain finite results, we assume a dipole form factor for the nucleon-quark-diquark coupling, instead of a point-like coupling. The results are compared with the time-reversal-odd ...
Charm quark mass dependence in the CTEQ NNLO global QCD analysis
Gao, Jun; Guzzi, Marco; Nadolsky, Pavel M.
2013-01-01
We discuss the impact of the charm quark mass in the CTEQ NNLO global analysis of parton distribution functions of the proton. The $\\bar{\\rm MS}$ mass $m_c(m_c)$ of the charm quark is extracted in the S-ACOT-$\\chi$ heavy-quark factorization scheme at ${\\cal O}(\\alpha_s^2)$ accuracy and found to be in agreement with the world-average value. Impact on $m_c(m_c)$ of combined HERA-1 data on semiinclusive charm production at HERA collider and contributing systematic uncertainties are reviewed.
Kiiskinen, A P
1999-01-01
A search for pair produced charged Higgs bosons was performed on the high energy data collected by DELPHI at LEP2. All three major final states, tau nu tau nu, cs tau nu and cscs were searched for. The analyses used a combination of event shape variables, di-jet masses and jet flavour tagging. The jet flavours were identified by using life time tagging and particle identification based on the RICH detector complemented by ionisation energy loss measurements. A similar type of jet flavour tagging was also used in extracting the |V sub c sub s | element of the Cabibbo-Kobayashi-Maskawa (CKM) matrix in hadronic decays of the W sup+- boson.
Electromagnetic properties of light and heavy baryons in the relativistic quark model
Energy Technology Data Exchange (ETDEWEB)
Nicmorus Marinescu, Diana
2007-06-14
One of the main challenges of nowadays low-energy physics remains the description of the internal structure of hadrons, strongly connected to the electromagnetic properties of matter. In this vein, the success of the relativistic quark model in the analysis of the hadron structure constitutes a solid motivation for the study carried out throughout this work. The relativistic quark model is extended to the investigation of static electromagnetic properties of both heavy and light baryons. The bare contributions to the magnetic moments of the single-, double- and triple-heavy baryons are calculated. Moreover, the relativistic quark model allows the study of the electromagnetic properties of the light baryon octet incorporating meson cloud contributions in a perturbative manner. The long disputed values of the multipole ratios E2/M1 and C2/M1 and the electromagnetic form factors of the N{yields}{delta}{gamma} transition are successfully reproduced. The relativistic quark model can be viewed as a quantum field theory approach based on a phenomenological Lagrangian coupling light and heavy baryons to their constituent quarks. In our approach the baryon is a composite object of three constituent quarks, at least in leading order. The effective interaction Lagrangian is written in terms of baryon and constituent quark fields. The effective action preserves Lorentz covariance and gauge invariance. The main ingredients of the model are already introduced at the level of the interaction Lagrangian: the three-quark baryon currents, the Gaussian distribution of the constituent quarks inside the baryon and the compositeness condition which sets an upper limit for the baryon-quark vertex. The S-matrix elements are expressed by a set of Feynman quark-diagrams. The model contains only few parameters, namely, the cut-off parameter of the Gaussian quark distribution and the free quark propagator, which are unambiguously determined from the best fit to the data. The heavy quark limit
Electromagnetic properties of light and heavy baryons in the relativistic quark model
International Nuclear Information System (INIS)
One of the main challenges of nowadays low-energy physics remains the description of the internal structure of hadrons, strongly connected to the electromagnetic properties of matter. In this vein, the success of the relativistic quark model in the analysis of the hadron structure constitutes a solid motivation for the study carried out throughout this work. The relativistic quark model is extended to the investigation of static electromagnetic properties of both heavy and light baryons. The bare contributions to the magnetic moments of the single-, double- and triple-heavy baryons are calculated. Moreover, the relativistic quark model allows the study of the electromagnetic properties of the light baryon octet incorporating meson cloud contributions in a perturbative manner. The long disputed values of the multipole ratios E2/M1 and C2/M1 and the electromagnetic form factors of the N→Δγ transition are successfully reproduced. The relativistic quark model can be viewed as a quantum field theory approach based on a phenomenological Lagrangian coupling light and heavy baryons to their constituent quarks. In our approach the baryon is a composite object of three constituent quarks, at least in leading order. The effective interaction Lagrangian is written in terms of baryon and constituent quark fields. The effective action preserves Lorentz covariance and gauge invariance. The main ingredients of the model are already introduced at the level of the interaction Lagrangian: the three-quark baryon currents, the Gaussian distribution of the constituent quarks inside the baryon and the compositeness condition which sets an upper limit for the baryon-quark vertex. The S-matrix elements are expressed by a set of Feynman quark-diagrams. The model contains only few parameters, namely, the cut-off parameter of the Gaussian quark distribution and the free quark propagator, which are unambiguously determined from the best fit to the data. The heavy quark limit within this
New results on CLEO's heavy quarks - bottom and charm
International Nuclear Information System (INIS)
While the top quark is confined to virtual reality for CLEO, the increased luminosity of the Cornell Electron Storage Ring (CESR) and the improved photon detection capabilities of the CLEO's open-quotes heavyclose quotes quarks - bottom and charm. I will describe new results in the B meson sector including the first observation of exclusive b → ulv decays, upper limits on gluonic penguin decay rates, and precise measurements of semileptonic and hadronic b → c branching fractions. The charmed hadron results that are discussed include the observation of isospin violation in Ds*+ decays, an update on measurements of the Ds+ decay constant, and the observation of a new excited Ξc charmed baryon. These measurements have had a large impact on our understanding of heavy quark physics
AUTHOR|(SzGeCERN)655637
The measurement of prompt photon associated with a b jet in proton-proton interactions can provide us insight into the inner structure of proton. This is because precision of determination of parton distribution functions of b quark and gluon can be increased by such a measurement. The measurement of cross-section of prompt photon associated with a b jet (process $pp\\longrightarrow \\gamma + b + X$) at $\\sqrt{s}$= 8 TeV with the ATLAS detector is presented. Full 8 TeV dataset collected by ATLAS during the year 2012 was used in this analysis. Corresponding integrated luminosity is 20.3 $fb^{-1}$. Fiducial differential cross-section as a function of photon transverse momentum at particle level was extracted from data and compared with the prediction of leading order event generator Pythia 8. Cross-section extracted from data is normalised independently on the Monte Carlo prediction. Values of data distribution lie above Monte Carlo values. The difference can be explained by presence of higher order effects not ...
Single top-quark production through flavour changing neutral currents
International Nuclear Information System (INIS)
Flavour Changing Neutral Current (FCNC) processes are highly suppressed in the Standard Model due to Glashow-Iliopoulos-Maiani (GIM) mechanism. However, in some extensions of the Standard Model such as supersymmetry (SUSY) and the 2-Higgs doublet model, the FCNC contributes at tree level, enhancing the branching ratio significantly. The FCNC are searched for in single top-quark production where a u(c)-quark interacts with a gluon, producing a single top-quark with no associated quark production. The data collected by the ATLAS detector during year 2012 is used with a center-of-mass energy of √(s)=8 TeV, corresponding to an integrated luminosity of ∝20 fb-1. The candidate signal events are selected by requiring one lepton, muon or electron, missing transverse momentum and exactly one jet originating from a b-quark in the final state. The separation between the signal and background events is enhanced by using neural network algorithms. The cross section upper limit at 95% C.L. is calculated following most frequently statistical approach using a binned likelihood method calculated from the full neural network output.
Instanton-dyon Ensembles III: Exotic Quark Flavors
Larsen, Rasmus
2016-01-01
"Exotic quarks" in the title refers to a modification of quark periodicity condition on the thermal circle by introduction of some phases -- known also as "flavor holonomies" -- different quark flavors. These phases provide a valuable tool, to be used for better understanding of deconfinement and chiral restoration phase transitions: by changing them one can dramatically modify both phase transitions. In the language of instanton constituents -- instanton-dyons or monopoles -- it has a very direct explanation: the interplay of flavor and color holonomies can switch topological zero modes between various dyon types. The model we will study in detail, the so called $Z_{N_c}$-symmetric QCD model with equal number of colors and flavors $N_c=N_f=2$ and special arrangement of flavor and color holonomies, ensure "most democratic" setting, in which each quark flavor and each dyon type are in one-to-one correspondence. The usual QCD has the opposite "most exclusive" arrangement: all quarks are antiperiodic and thus al...
Measurement of strange-quark contributions to the nucleon's form factors at Q(2) = 0.230 (GeV/c)(2).
Maas, F E; Achenbach, P; Aulenbacher, K; Baunack, S; Capozza, L; Diefenbach, J; Grimm, K; Imai, Y; Hammel, T; von Harrach, D; Kabuss, E M; Kothe, R; Lee, J H; Lorente, A; Lopes Ginja, A; Nungesser, L; Schilling, E; Stephan, G; Weinrich, C; Altarev, I; Arvieux, J; Collin, B; Frascaria, R; Guidal, M; Kunne, R; Marchand, D; Morlet, M; Ong, S; van de Wiele, J; Kowalski, S; Plaster, B; Suleiman, R; Taylor, S
2004-07-01
We report on a measurement of the parity-violating asymmetry in the scattering of longitudinally polarized electrons on unpolarized protons at a Q2 of 0.230 (GeV/c)(2) and a scattering angle of theta (e) = 30 degrees - 40 degrees. Using a large acceptance fast PbF2 calorimeter with a solid angle of delta omega = 0.62 sr, the A4 experiment is the first parity violation experiment to count individual scattering events. The measured asymmetry is A(phys)=(-5.44+/-0.54(stat)+/-0.26(sys))x10(-6). The standard model expectation assuming no strangeness contributions to the vector form factors is A(0) = (-6.30+/-0.43) x 10(-6). The difference is a direct measurement of the strangeness contribution to the vector form factors of the proton. The extracted value is G(s)(E) + 0.225G(s)(M) = 0.039+/-0.034 or F(s)(1) + 0.130F(s)(2) = 0.032+/-0.028. PMID:15323904
Searches for new quarks and leptons in Z boson decays
International Nuclear Information System (INIS)
Searches for the decay of Z bosons into pairs of new quarks and leptons in a data sample including 455 hadronic Z decays are presented. The Z bosons were produced in electon-positron annihilations at the SLAC Linear Collider operating in the center-of-mass energy range from 89.2 to 93.0 GeV. The Standard Model provides no prediction for fermion masses and does not exclude new generations of fermions. The existence and masses of these new particles may provide valuable information to help understand the pattern of fermion masses, and physics beyond the Standard Model. Specific searches for top quarks and sequential fourth generation charge--1/3(b') quarks are made considering a variety of possible standard and non-standard decay modes. In addition, searches for sequential fourth generation massive neutrinos ν4 and their charged lepton partners L- are pursued. The ν4 may be stable or decay through mixing to the lighter generations. The data sample is examined for new particle topologies of events with high-momentum isolated tracks, high-energy isolated photons, spherical event shapes, and detached vertices. No evidence is observed for the production of new quarks and leptons. 95% confidence lower mass limits of 40.7 GeV/c2 for the top quark and 42.0 GeV/c2 for the b'-quark mass are obtained regardless of the branching fractions to the considered decay modes. A significant range of mixing matrix elements of ν4 to other generation neutrinos for a ν4 mass from 1 GeV/c2 to 43 GeV/c2 is excluded at 95% confidence level. Measurements of the upper limit of the invisible width of the Z exclude additional values of the ν4 mass and mixing matrix elements, and also permit the exclusion of a region in the L- mass versus ν4 mass plane
Bottom quark mass from Υ mesons
International Nuclear Information System (INIS)
The bottom quark pole mass Mb is determined using a sum rule which relates the masses and the electronic decay widths of the Υ mesons to large n moments of the vacuum polarization function calculated from nonrelativistic quantum chromodynamics. The complete set of next-to-next-to-leading order [i.e., O(αs2,αsv,v2) where v is the bottom quark c.m. velocity] corrections is calculated and leads to a considerable reduction of theoretical uncertainties compared to a pure next-to-leading order analysis. However, the theoretical uncertainties remain much larger than the experimental ones. For a two parameter fit for Mb, and the strong M bar S coupling αs, and using the scanning method to estimate theoretical uncertainties, the next-to-next-to-leading order analysis yields 4.74 GeV ≤Mb≤4.87 GeV and 0.096≤αs(Mz)≤0.124 if experimental uncertainties are included at the 95% confidence level and if two-loop running for αs is employed. Mb and αs have a sizable positive correlation. For the running M bar S bottom quark mass this leads to 4.09 GeV ≤mb(MΥ(1S)/2)≤4.32 GeV. If αs is taken as an input, the result for the bottom quark pole mass reads 4.78 GeV ≤Mb≤4.98 GeV[4.08 GeV ≤mb(MΥ(1S)/2)≤4.28 GeV] for 0.114≤αs(Mz)≤0.122. The discrepancies between the results of three previous analyses on the same subject by Voloshin, Jamin, and Pich and Kuehn et al. are clarified. A comprehensive review on the calculation of the heavy-quark - antiquark pair production cross section through a vector current at next-to-next-to leading order in the nonrelativistic expansion is presented. copyright 1998 The American Physical Society
Updated Estimate of Running Quark Masses
Fusaoka, Hideo; Koide, Yoshio
1997-01-01
Stimulated by recent development of the calculation methods of the running quark masses $m_q(\\mu)$ and renewal of the input data, for the purpose of making a standard table of $m_q(\\mu)$ for convenience of particle physicists, the values of $m_q(\\mu)$ at various energy scales $\\mu$ ($\\mu = 1$ GeV, $\\mu = m_c$, $\\mu=m_b$, $\\mu=m_t$ and so on), especially at $\\mu = m_Z$, are systematically evaluated by using the mass renormalization equations and by taking into consideration a matching conditio...
Top Quark Spin Correlations at the Tevatron
Energy Technology Data Exchange (ETDEWEB)
Head, Tim; /Manchester U.
2010-07-01
Recent measurements of the correlation between the spin of the top and the spin of the anti-top quark produced in proton anti-proton scattering at a center of mass energy of {radical}s = 1.96 Tev by the CDF and D0 collaborations are discussed. using up to 4.3 fb{sup -1} of data taken with the CDF and D0 detectors the spin correlation parameter C, the degree to which the spins are correlated, is measured in dileptonic and semileptonic final states. The measurements are found to be in agreement with Standard Model predictions.
Differences between heavy and light quarks
Maris, P.; Roberts, C. D.
1997-01-01
The quark Dyson-Schwinger equation shows that there are distinct differences between light and heavy quarks. The dynamical mass function of the light quarks is characterised by a sharp increase below 1 GeV, whereas the mass function of the heavy quarks is approximately constant in this infrared region. As a consequence, the heavy-meson masses increase linearly with the current-quark masses, whereas the light pseudoscalar meson masses are proportional to the square root of the current-quark ma...
Strange Quark Matter Status and Prospects
Sandweiss, J.
2004-01-01
The existence of quark states with more than three quarks is allowed in QCD. The stability of such quark matter states has been studied with lattice QCD and phenomenological bag models, but is not well constrained by theory. The addition of strange quarks to the system allows the quarks to be in lower energy states despite the additional mass penalty. There is additional stability from reduced Coulomb repulsion. SQM is expected to have a low Z/A. Stable or metastable massive multiquark states contain u, d, and s quarks.
The Quark Spin Distributions of the Nucleon
Ma, Bo-Qiang; Schmidt, Ivan; Soffer, Jacques
1997-01-01
The quark helicity measured in polarized deep inelastic scattering is different from the quark spin in the rest frame of the nucleon. We point out that the quark spin distributions $\\Delta q_{RF}(x)$ are connected with the quark helicity distributions $\\Delta q(x)$ and the quark transversity distributions $\\delta q(x)$ by an approximate relation: $\\Delta q_{RF}(x) + \\Delta q(x)=2 \\delta q(x)$. This relation will be useful in order to measure the rest frame (or quark model) spin distributions ...
Propagators and Masses of Light Quarks
Institute of Scientific and Technical Information of China (English)
ZHOU Li-Juan; ZHU Ji-Zhen; MA Wei-Xing
2003-01-01
Based on Dyson-Schwinger equations in "rainbow" approximation, fully dressed confining quark propagator is obtained, and then the masses of light quarks (mu, md, and ms) are derived from the fully dressed confining quark propagator. At the same time, the local and non-local quark vacuum condensates as well as the quark-gluon mixed condensate are also predicted. Furthermore, the quark masses are also deduced from the Gell-Mann-Oakes-Renner relation and chiral perturbative theory. The results from different methods are consistent with each other.
Propagators and Masses of Light Quarks
Institute of Scientific and Technical Information of China (English)
ZHOULi-Juan; ZHUJi-Zhen; MAWei-Xing
2003-01-01
Based on Dyson-Schwinger equations in “rainbow” approximation, fully dressed confining quark propagator is obtained, and then the masses of light quarks (mu, md, and ms) are derived from the fully dressed confining quark propagator. At the same time, the local and non-local quark vacuum condensates as well as the quark-gluon mixed condensate are also predicted. Furthermore, the quark masses are also deduced from the Gell-Mann-Oakes-Renner relation and chiral perturbative theory. The results from different methods are consistent with each other.
Heavy quark energy loss in nuclear medium
International Nuclear Information System (INIS)
Multiple scattering, modified fragmentation functions and radiative energy loss of a heavy quark propagating in a nuclear medium are investigated in perturbative QCD. Because of the quark mass dependence of the gluon formation time, the medium size dependence of heavy quark energy loss is found to change from a linear to a quadratic form when the initial energy and momentum scale are increased relative to the quark mass. The radiative energy loss is also significantly suppressed relative to a light quark due to the suppression of collinear gluon emission by a heavy quark
Recent top quark results from ATLAS
Mcgoldrick, Garrin; The ATLAS collaboration
2016-01-01
The top quark is the heaviest known fundamental particle. As it is the only quark that decays before it hadronizes, this gives us the unique opportunity to probe the properties of bare quarks. This talk will focus on a few recent precision top quark measurements by the ATLAS Collaboration: fiducial top pair and single top production cross sections including differential distributions will be presented alongside selected measurements of top quark properties. The results include the first top quark measurements at 13 TeV using data from the 2015 LHC run.
Selected top quark mass measurements at CMS
Bouvier, Elvire
2016-01-01
Selected measurements of the top quark mass are presented, obtained from CMS data collected in proton-proton collisions at the LHC at center-of-mass energies of 7, 8, and 13 TeV. ``Standard'' techniques are employed in each decay channel of top quark pair events and their results are combined. The mass of the top quark is also measured using several ``alternative'' methods, including measurements from shapes of top quark decay distributions in single top quark and top quark pair events as well as pole mass measurements.
Measurement of bottom quark production in 1.8 TeV p bar p collisions using muons from b-quark decays
International Nuclear Information System (INIS)
We present a measurement of the b-quark cross section in 1.8 TeV p-bar p collisions recorded with the Collider Detector at Fermilab using muonic b-quark decays. In the central rapidity region (|yb|Tb>21 GeV/c (29 GeV/c). Comparisons are made to previous measurements and next-to-leading order QCD calculations
Theory of hadronic production of heavy quarks
International Nuclear Information System (INIS)
Conventional theoretical predictions for hadronic production of heavy quarks (Q anti Q) are reviewed and confronted with data. Perturbative hard scattering predictions agree qualitatively well with hidden Q anti Q production (e.g., psi, chi, T) whereas for open Q anti Q-production (e.g., pp → Λ/sub c/+X) additional mechanisms or inputs are needed to explain the forwardly produced Λ/sub c/+ at ISR. It is suggested that the presence of c anti c-pairs on the 1 to 2% level in the hadron Fock state decomposition (intrinsic charm) gives a natural description of the ISR data. The theoretical foundations of the intrinsic charm hypotheses together with its consequences for lepton-induced reactions is discussed in some detail
Static quark-antiquark potential in the quark-gluon plasma from lattice QCD.
Burnier, Yannis; Kaczmarek, Olaf; Rothkopf, Alexander
2015-02-27
We present a state-of-the-art determination of the complex valued static quark-antiquark potential at phenomenologically relevant temperatures around the deconfinement phase transition. Its values are obtained from nonperturbative lattice QCD simulations using spectral functions extracted via a novel Bayesian inference prescription. We find that the real part, both in a gluonic medium, as well as in realistic QCD with light u, d, and s quarks, lies close to the color singlet free energies in Coulomb gauge and shows Debye screening above the (pseudo)critical temperature T_{c}. The imaginary part is estimated in the gluonic medium, where we find that it is of the same order of magnitude as in hard-thermal loop resummed perturbation theory in the deconfined phase. PMID:25768756
Static quark-antiquark potential in the quark-gluon plasma from lattice QCD
Burnier, Yannis; Rothkopf, Alexander
2014-01-01
We present a state-of-the-art determination of the complex valued static quark-antiquark potential at phenomenologically relevant temperatures around the deconfinement phase transition. Its values are obtained from non-perturbative lattice QCD simulations using spectral functions extracted via a novel Bayesian inference prescription. We find that the real part, both in a gluonic medium as well as in realistic QCD with light $u$, $d$ and $s$ quarks, lies close to the color singlet free energies in Coulomb gauge and shows Debye screening above the (pseudo) critical temperature $T_c$. The imaginary part is estimated in the gluonic medium, where we find that it is of the same order of magnitude as in hard-thermal loop resummed perturbation theory in the deconfined phase.
Quark Number Susceptibility in Hard Thermal Loop Approximation
Chakraborty, Purnendu; Mustafa, Munshi G.; Thoma, Markus H.
2001-01-01
We calculate the quark number susceptibility in the deconfined phase of QCD using the hard thermal loop (HTL) approximation for the quark propagator. This improved perturbation theory takes into account important medium effects such as thermal quark masses and Landau damping in the quark-gluon plasma. We explicitly show that the Landau damping part in the quark propagator for spacelike quark momenta does not contribute to the quark number susceptibility due to the quark number conservation. W...
Quark masses and strong coupling constant in 2+1 flavor QCD
Maezawa, Y
2016-01-01
We present a determination of the strange, charm and bottom quark masses as well as the strong coupling constant in 2+1-flavor lattice QCD simulations using Highly Improved Staggered Quark action. The ratios of the charm quark mass to the strange quark mass and the bottom quark mass to the charm quark mass are obtained from the meson masses calculated on the lattice and found to be $m_c/m_s=11.871(91)$ and $m_b/m_c=4.528(57)$ in the continuum limit. We also determine the strong coupling constant and the charm quark mass using the moments of pseudoscalar charmonium correlators: $\\alpha_s(\\mu=m_c)=0.3697(75)$ and $m_c(\\mu=m_c)=1.267(11)$ GeV. Our result for $\\alpha_s$ corresponds to the determination of the strong coupling constant at the lowest energy scale so far and is translated to the value $\\alpha_s(\\mu=M_Z,n_f=5)=0.11622(75)$.
Determination of the width of the top quark
Energy Technology Data Exchange (ETDEWEB)
Abazov, Victor Mukhamedovich; /Dubna, JINR; Abbott, Braden Keim; /Oklahoma U.; Abolins, Maris A.; /Michigan State U.; Acharya, Bannanje Sripath; /Tata Inst.; Adams, Mark Raymond; /Illinois U., Chicago; Adams, Todd; /Florida State U.; Alexeev, Guennadi D.; /Dubna, JINR; Alkhazov, Georgiy D.; /St. Petersburg, INP; Alton, Andrew K.; /Michigan U. /Augustana Coll., Sioux Falls; Alverson, George O.; /Northeastern U.; Alves, Gilvan Augusto; /Rio de Janeiro, CBPF /Nijmegen U.
2010-09-01
We extract the total width of the top quark, {Lambda}{sub t}, from the partial decay width {Lambda}(t {yields} Wb) measured using the t-channel cross section for single top quark production and from the branching fraction B(t {yields} Wb) measured in t{bar t} events using up to 2.3 fb{sup -1} of integrated luminosity collected by the D0 Collaboration at the Tevatron p{bar p} Collider. The result is {Lambda}{sub t} = 1.99{sub -0.55}{sup +0.69} GeV, which translates to a top-quark lifetime of {tau}{sub t} = (3.3{sub -0.9}{sup +1.3}) x 10{sup -25} s. Assuming a high mass fourth generation b{prime} quark and unitarity of the four-generation quark-mixing matrix, we set the first upper limit on |V{sub tb{prime}}| < 0.63 at 95% C.L.
Constituent quark scaling violation due to baryon number transport
Dunlop, J; Sorensen, P
2011-01-01
In ultra-relativistic heavy ion collisions at $\\roots\\approx200$ GeV, the azimuthal emission anisotropy of hadrons with low and intermediate transverse momentum ($p_T\\lesssim 4$ GeV/c) displays an intriguing scaling. In particular, the baryon (meson) emission patterns are consistent with a scenario in which a bulk medium of flowing quarks coalesces into three-quark (two-quark) "bags." While a full understanding of this number of constituent quark (NCQ) scaling remains elusive, it is suggestive of a thermalized bulk system characterized by colored dynamical degrees of freedom-- a quark-gluon plasma (QGP). In this scenario, one expects the scaling to break down as the central energy density is reduced below the QGP formation threshold; for this reason, NCQ-scaling violation searches are of interest in the energy scan program at the Relativistic Heavy Ion Collider (RHIC). However, as $\\roots$ is reduced, it is not only the initial energy density that changes; there is also an increase in the net baryon number at...
Measurement of heavy-quark jet photoproduction at HERA
International Nuclear Information System (INIS)
Photoproduction of beauty and charm quarks in events with at least two jets has been measured with the ZEUS detector at HERA using an integrated luminosity of 133 pb-1. The fractions of jets containing b and c quarks were extracted using the invariant mass of charged tracks associated with secondary vertices and the decay-length significance of these vertices. Differential cross sections as a function of jet transverse momentum, pjetT, and pseudorapidity, ηjet, were measured. The data are compared with previous measurements and are well described by next-to-leading-order QCD predictions. (orig.)
Measurement of heavy-quark jet photoproduction at HERA
Abramowicz, H; Adamczyk, L; Adamus, M; Aggarwal, R; Antonelli, S; Antonioli, P; Antonov, A; Arneodo, M; Aushev, V; Aushev, Y; Bachynska, O; Bamberger, A; Barakbaev, A N; Barbagli, G; Bari, G; Barreiro, F; Bartosik, N; Bartsch, D; Basile, M; Behnke, O; Behr, J; Behrens, U; Bellagamba, L; Bertolin, A; Bhadra, S; Bindi, M; Blohm, C; Bokhonov, V; Bołd, T; Bolilyi, O; Bondarenko, K; Boos, E G; Borras, K; Boscherini, D; Bot, D; Brock, I; Brownson, E; Brugnera, R; Brümmer, N; Bruni, A; Bruni, G; Brzozowska, B; Bussey, P J; Bylsma, B; Caldwell, A; Capua, M; Carlin, R; Catterall, C D; Chekanov, S; Chwastowski, J; Ciborowski, J; Ciesielski, R; Cifarelli, L; Cindolo, F; Contin, A; Cooper-Sarkar, A M; Coppola, N; Corradi, M; Corriveau, F; Costa, M; D'Agostini, G; Corso, F Dal; del Peso, J; Dementiev, R K; De Pasquale, S; Derrick, M; Devenish, R C E; Dobur, D; Dolgoshein, B A; Dolinska, G; Doyle, A T; Drugakov, V; Durkin, L S; Dusini, S; Eisenberg, Y; Ermolov, P F; Eskreys, A; Fang, S; Fazio, S; Ferrando, J; Ferrero, M I; Figiel, J; Forrest, M; Foster, B; Fourletov, S; Gach, G; Galas, A; Gallo, E; Garfagnini, A; Geiser, A; Gialas, I; Gladilin, L K; Gladkov, D; Glasman, C; Gogota, O; Golubkov, Yu A; Göttlicher, P; Grabowska-Bołd, I; Grebenyuk, J; Gregor, I; Grigorescu, G; Grzelak, G; Gueta, O; Gwenlan, C; Haas, T; Hain, W; Hamatsu, R; Hart, J C; Hartmann, H; Hartner, G; Hilger, E; Hochman, D; Hori, R; Horton, K; Hüttmann, A; Ibrahim, Z A; Iga, Y; Ingbir, R; Ishitsuka, M; Jakob, H -P; Januschek, F; Jimenez, M; Jones, T W; Jüngst, M; Kadenko, I; Kahle, B; Kamaluddin, B; Kananov, S; Kanno, T; Karshon, U; Karstens, F; Katkov, I I; Kaur, M; Kaur, P; Keramidas, A; Khein, L A; Kim, J Y; Kisielewska, D; Kitamura, S; Klanner, R; Klein, U; Koffeman, E; Kooijman, P; Korol, Ie; Korzhavina, I A; Kotański, A; Kötz, U; Kowalski, H; Kulinski, P; Kuprash, O; Kuze, M; Lee, A; Levchenko, B B; Levy, A; Libov, V; Limentani, S; Ling, T Y; Lisovyi, M; Lobodzinska, E; Lohmann, W; Löhr, B; Lohrmann, E; Long, K R; Longhin, A; Lontkovskyi, D; Lukina, O Yu; Łużniak, P; Maeda, J; Magill, S; Makarenko, I; Malka, J; Mankel, R; Margotti, A; Marini, G; Martin, J F; Mastroberardino, A; Mattingly, M C K; Melzer-Pellmann, I -A; Mergelmeyer, S; Miglioranzi, S; Idris, F Mohamad; Monaco, V; Montanari, A; Morris, J D; Mujkic, K; Musgrave, B; Nagano, K; Namsoo, T; Nania, R; Nicholass, D; Nigro, A; Ning, Y; Nobe, T; Noor, U; Notz, D; Nowak, R J; Nuncio-Quiroz, A E; Oh, B Y; Okazaki, N; Oliver, K; Olkiewicz, K; Onishchuk, Yu; Papageorgiu, K; Parenti, A; Paul, E; Pawlak, J M; Pawlik, B; Pelfer, P G; Pellegrino, A; Perlanski, W; Perrey, H; Piotrzkowski, K; Plucinski, P; Pokrovskiy, N S; Polini, A; Proskuryakov, A S; Przybycień, M; Raval, A; Reeder, D D; Reisert, B; Ren, Z; Repond, J; Ri, Y D; Robertson, A; Roloff, P; Ron, E; Rubinsky, I; Ruspa, M; Sacchi, R; Salii, A; Samson, U; Sartorelli, G; Savin, A A; Saxon, D H; Schioppa, M; Schlenstedt, S; Schleper, P; Schmidke, W B; Schneekloth, U; Schönberg, V; Schörner-Sadenius, T; Schwartz, J; Sciulli, F; Shcheglova, L M; Shehzadi, R; Shimizu, S; Singh, I; Skillicorn, I O; Słomiński, W; Smith, W H; Sola, V; Solano, A; Son, D; Sosnovtsev, V; Spiridonov, A; Stadie, H; Stanco, L; Stern, A; Stewart, T P; Stifutkin, A; Stopa, P; Suchkov, S; Susinno, G; Suszycki, L; Sztuk-Dambietz, J; Szuba, D; Szuba, J; Tapper, A D; Tassi, E; Terrón, J; Theedt, T; Tiecke, H; Tokushuku, K; Tomalak, O; Tomaszewska, J; Tsurugai, T; Turcato, M; Tymieniecka, T; Uribe-Estrada, C; Vázquez, M; Verbytskyi, A; Viazlo, O; Vlasov, N N; Volynets, O; Walczak, R; Abdullah, W A T Wan; Whitmore, J J; Whyte, J; Wiggers, L; Wing, M; Wlasenko, M; Wolf, G; Wolfe, H; Wrona, K; Yagües-Molina, A G; Yamada, S; Yamazaki, Y; Yoshida, R; Youngman, C; Żarnecki, A F; Zawiejski, L; Zenaiev, O; Zeuner, W; Zhautykov, B O; Zhmak, N; Zhou, C; Zichichi, A; Zolko, M; Zotkin, D S; Zulkapli, Z
2011-01-01
Photoproduction of beauty and charm quarks in events with at least two jets has been measured with the ZEUS detector at HERA using an integrated luminosity of 133 $pb^{-1}$. The fractions of jets containing b and c quarks were extracted using the invariant mass of charged tracks associated with secondary vertices and the decay-length significance of these vertices. Differential cross sections as a function of jet transverse momentum, $p_{T}^{\\text{jet}}$, and pseudorapidity, $\\eta^{\\text{jet}}$, were measured. The data are compared with previous measurements and are well described by next-to-leading-order QCD predictions.
Predicting charmonium and bottomonium spectra with a quark harmonic oscillator
Norbury, J. W.; Badavi, F. F.; Townsend, L. W.
1986-01-01
The nonrelativistic quark model is applied to heavy (nonrelativistic) meson (two-body) systems to obtain sufficiently accurate predictions of the spin-averaged mass levels of the charmonium and bottomonium spectra as an example of the three-dimensional harmonic oscillator. The present calculations do not include any spin dependence, but rather, mass values are averaged for different spins. Results for a charmed quark mass value of 1500 MeV/c-squared show that the simple harmonic oscillator model provides good agreement with experimental values for 3P states, and adequate agreement for the 3S1 states.
Measurement of heavy-quark jet photoproduction 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, Cracow (PL). Faculty of Physics and Applied Computer Science] (and others)
2011-04-15
Photoproduction of beauty and charm quarks in events with at least two jets has been measured with the ZEUS detector at HERA using an integrated luminosity of 133 pb{sup -1}. The fractions of jets containing b and c quarks were extracted using the invariant mass of charged tracks associated with secondary vertices and the decay-length significance of these vertices. Differential cross sections as a function of jet transverse momentum, p{sup jet}{sub T}, and pseudorapidity, {eta}{sup jet}, were measured. The data are compared with previous measurements and are well described by next-to-leading-order QCD predictions. (orig.)
Duality between quark-quark and quark-antiquark pairing in 1+1 dimensional large N models
Thies, Michael
2003-01-01
We identify a canonical transformation which maps the chiral Gross-Neveu model onto a recently proposed Cooper pair model. Baryon number and axial charge are interchanged. The same physics can be described either as chiral symmetry breaking (quark-antiquark pairing) or as superconductivity (quark-quark pairing).
Measuring the sea quark polarization
International Nuclear Information System (INIS)
Spin is a fundamental degree of freedom and measuring the spin structure functions of the nucleon should be a basic endeavor for hadron physics. Polarization experiments have been the domain of fixed target experiments. Over the years large transverse asymmetries have been observed where the prevailing QCD theories predicted little or no asymmetries, and conversely the latest deep inelastic scattering experiments of polarized leptons from polarized targets point to the possibility that little of the nucleon spin is carried by the valence quarks. The possibility of colliding high luminosity polarized proton beams in the Brookhaven Relativistic Heavy Ion Collider (RHIC) provides a great opportunity to extend these studies and systematically probe the spin dependent parton distributions specially to those reactions that are inaccessible to current experiments. This presentation focuses on the measurement of sea quark and possibly the strange quark polarization utilizing the approved RHIC detectors
Horn, D.
2015-03-01
The quark model emerged from the Gell-Mann-Ne'eman flavor SU(3) symmetry. Its development, in the context of strong interactions, took place in a heuristic theoretical framework, referred to as the Bootstrap Era. Setting the background for the dominant ideas in strong interaction of the early 1960s, we outline some aspects of the constituent quark model. An independent theoretical development was the emergence of hadron duality in 1967, leading to a realization of the Bootstrap idea by relating hadron resonances (in the s-channel) with Regge pole trajectories (in t- and u-channels). The synthesis of duality with the quark-model has been achieved by duality diagrams, serving as a conceptual framework for discussing many aspects of hadron dynamics toward the end of the 1960s.
Gluon propagator with dynamical quarks
Papavassiliou, Joannis
2014-01-01
We review recent work on the effects of quark loops on the gluon propagator in the Landau gauge, relying mainly on the Schwinger-Dyson equations that describe the two-point sector of QCD. Particularly important in this context is the detailed study of how the standard gluon mass generation mechanism, which is responsible for the infrared finiteness of the quenched gluon propagator, is affected by the inclusions of dynamical quarks. This issue is especially relevant and timely, given the qualitative picture that emerges from recent unquenched lattice simulations. Our results demonstrate clearly that the gluon mass generation persists, and that the corresponding saturation points of the unquenched gluon propagators are progressively suppressed, as the number of quark flavors increases.
On the Coulomb gauge quark propagator
International Nuclear Information System (INIS)
Full text: A solution of the quark Dyson-Schwinger equation including transverse gluons is presented. The corresponding retardation effects in the quark propagator are discussed. Especially, their effects on confinement properties and dynamical mass generation are described. (author)
Boosted top quarks and jet structure
Energy Technology Data Exchange (ETDEWEB)
Schaetzel, Sebastian [Ruprecht-Karls-Universitaet Heidelberg, Physikalisches Institut, Heidelberg (Germany)
2015-09-15
The Large Hadron Collider is the first particle accelerator that provides high enough energy to produce large numbers of boosted top quarks. The decay products of these top quarks are confined to a cone in the top quark flight direction and can be clustered into a single jet. Top quark reconstruction then amounts to analysing the structure of the jet and looking for subjets that are kinematically compatible with top quark decay. Many techniques have been developed in this context to identify top quarks in a large background of non-top jets. This article reviews the results obtained using data recorded in the years 2010-2012 by the experiments ATLAS and CMS. Studies of Standard Model top quark production and searches for new massive particles that decay to top quarks are presented. (orig.)
Boosted top quarks and jet structure
International Nuclear Information System (INIS)
The Large Hadron Collider is the first particle accelerator that provides high enough energy to produce large numbers of boosted top quarks. The decay products of these top quarks are confined to a cone in the top quark flight direction and can be clustered into a single jet. Top quark reconstruction then amounts to analysing the structure of the jet and looking for subjets that are kinematically compatible with top quark decay. Many techniques have been developed in this context to identify top quarks in a large background of non-top jets. This article reviews the results obtained using data recorded in the years 2010-2012 by the experiments ATLAS and CMS. Studies of Standard Model top quark production and searches for new massive particles that decay to top quarks are presented. (orig.)
Boosted top quarks and jet structure
Schätzel, Sebastian
2015-09-01
The Large Hadron Collider is the first particle accelerator that provides high enough energy to produce large numbers of boosted top quarks. The decay products of these top quarks are confined to a cone in the top quark flight direction and can be clustered into a single jet. Top quark reconstruction then amounts to analysing the structure of the jet and looking for subjets that are kinematically compatible with top quark decay. Many techniques have been developed in this context to identify top quarks in a large background of non-top jets. This article reviews the results obtained using data recorded in the years 2010-2012 by the experiments ATLAS and CMS. Studies of Standard Model top quark production and searches for new massive particles that decay to top quarks are presented.
Study of quark flow in exclusive reactions at 90 degrees in the center of mass (AGS E838)
International Nuclear Information System (INIS)
We report a study of quark flow in 20 exclusive reactions measured at Brookhaven National Laboratory's AGS with a beam momentum of 5.9 GeV/c at 90 degree in the center of mass. This experiment confirms the strong quark flow reaction mechanism dependence of two-body hadron scattering at large angles seen at 9.9 GeV/c. Large differences in cross sections for different reactions are consistent with the dominance of quark interchange in these 90 degree reactions, and indicate that pure gluon exchange and quark/antiquark annihilation diagrams are less important. copyright 1995 American Institute of Physics
A possibility of quark spin polarized phase in high density quark matter
Tsue, Y.; da Providencia, J.; Providencia, C.; Yamamura, M.; Bohr, H.
2015-01-01
It is shown that the quark spin polarization may occur for each quark flavor by the use of the Nambu-Jona-Lasinio model with a tensor-type four-point interaction between quarks, while the two-flavor color superconducting phase in two-flavor case may be realized at high density quark matter.
Explicit and Dynamical Chiral Symmetry Bresking in an Effective Quark-Quark Interaction Model
Institute of Scientific and Technical Information of China (English)
宗红石; 吴小华; 侯丰尧; 赵恩广
2004-01-01
A method for obtaining the small current quark mass effect on the dressed quark propagator from an effective quark-quark interaction model is developed. Within this approach both the explicit and dynamical chiral symmetry breakings are analysed. A comparison with the previous results is given.
Radiative corrections to the quark-gluon-Reggeized quark vertex in QCD
International Nuclear Information System (INIS)
This paper is devoted to the calculation of quark-gluon-Reggeized quark effective vertex in perturbative QCD in the next-to-leading order. The case of QCD with massive quarks is considered. This vertex has a number of applications, in particular, the result can be used for determination of the next-to-leading correction to the massive Reggeized quark trajectory
Heavy quark chemical equilibration rate as a transport coefficient
Bodeker, D
2012-01-01
Motivated by indications that heavy (charm and bottom) quarks interact strongly at temperatures generated in heavy ion collision experiments, we suggest a non-perturbative definition of a heavy quark chemical equilibration rate as a transport coefficient. Within leading-order perturbation theory (corresponding to 3-loop level), the definition is argued to reduce to an expression obtained from the Boltzmann equation. Around T ~ 400 MeV, an order-of-magnitude estimate for charm yields a rate Gamma^{-1}_{chem} > 60 fm/c which remains too slow to play a practical role in current experiments. However, the rate increases rapidly with T and, due to non-linear effects, also if the initial state contains an overabundance of heavy quarks.
Khachatryan, Vardan; Tumasyan, Armen; Adam, Wolfgang; Bergauer, Thomas; Dragicevic, Marko; Erö, Janos; Friedl, Markus; Fruehwirth, Rudolf; Ghete, Vasile Mihai; Hartl, Christian; Hörmann, Natascha; Hrubec, Josef; Jeitler, Manfred; Kiesenhofer, Wolfgang; Knünz, Valentin; Krammer, Manfred; Krätschmer, Ilse; Liko, Dietrich; Mikulec, Ivan; Rabady, Dinyar; Rahbaran, Babak; Rohringer, Herbert; Schöfbeck, Robert; Strauss, Josef; Treberer-Treberspurg, Wolfgang; Waltenberger, Wolfgang; Wulz, Claudia-Elisabeth; Mossolov, Vladimir; Shumeiko, Nikolai; Suarez Gonzalez, Juan; Alderweireldt, Sara; Bansal, Sunil; Cornelis, Tom; De Wolf, Eddi A; Janssen, Xavier; Knutsson, Albert; Lauwers, Jasper; Luyckx, Sten; Ochesanu, Silvia; Rougny, Romain; Van De Klundert, Merijn; Van Haevermaet, Hans; Van Mechelen, Pierre; Van Remortel, Nick; Van Spilbeeck, Alex; Blekman, Freya; Blyweert, Stijn; D'Hondt, Jorgen; Daci, Nadir; Heracleous, Natalie; Keaveney, James; Lowette, Steven; Maes, Michael; Olbrechts, Annik; Python, Quentin; Strom, Derek; Tavernier, Stefaan; Van Doninck, Walter; Van Mulders, Petra; Van Onsem, Gerrit Patrick; Villella, Ilaria; Caillol, Cécile; Clerbaux, Barbara; De Lentdecker, Gilles; Dobur, Didar; Favart, Laurent; Gay, Arnaud; Grebenyuk, Anastasia; Léonard, Alexandre; Mohammadi, Abdollah; Perniè, Luca; Randle-conde, Aidan; Reis, Thomas; Seva, Tomislav; Thomas, Laurent; Vander Velde, Catherine; Vanlaer, Pascal; Wang, Jian; Zenoni, Florian; Adler, Volker; Beernaert, Kelly; Benucci, Leonardo; Cimmino, Anna; Costantini, Silvia; Crucy, Shannon; Dildick, Sven; Fagot, Alexis; Garcia, Guillaume; Mccartin, Joseph; Ocampo Rios, Alberto Andres; Poyraz, Deniz; Ryckbosch, Dirk; Salva Diblen, Sinem; Sigamani, Michael; Strobbe, Nadja; Thyssen, Filip; Tytgat, Michael; Yazgan, Efe; Zaganidis, Nicolas; Basegmez, Suzan; Beluffi, Camille; Bruno, Giacomo; Castello, Roberto; Caudron, Adrien; Ceard, Ludivine; Da Silveira, Gustavo Gil; Delaere, Christophe; Du Pree, Tristan; Favart, Denis; Forthomme, Laurent; Giammanco, Andrea; Hollar, Jonathan; Jafari, Abideh; Jez, Pavel; Komm, Matthias; Lemaitre, Vincent; Nuttens, Claude; Perrini, Lucia; Pin, Arnaud; Piotrzkowski, Krzysztof; Popov, Andrey; Quertenmont, Loic; Selvaggi, Michele; Vidal Marono, Miguel; Vizan Garcia, Jesus Manuel; Beliy, Nikita; Caebergs, Thierry; Daubie, Evelyne; Hammad, Gregory Habib; Aldá Júnior, Walter Luiz; Alves, Gilvan; Brito, Lucas; Correa Martins Junior, Marcos; Dos Reis Martins, Thiago; Molina, Jorge; Mora Herrera, Clemencia; Pol, Maria Elena; Rebello Teles, Patricia; Carvalho, Wagner; Chinellato, Jose; Custódio, Analu; Da Costa, Eliza Melo; De Jesus Damiao, Dilson; De Oliveira Martins, Carley; Fonseca De Souza, Sandro; Malbouisson, Helena; Matos Figueiredo, Diego; Mundim, Luiz; Nogima, Helio; Prado Da Silva, Wanda Lucia; Santaolalla, Javier; Santoro, Alberto; Sznajder, Andre; Tonelli Manganote, Edmilson José; Vilela Pereira, Antonio; Bernardes, Cesar Augusto; Dogra, Sunil; Tomei, Thiago; De Moraes Gregores, Eduardo; Mercadante, Pedro G; Novaes, Sergio F; Padula, Sandra; Aleksandrov, Aleksandar; Genchev, Vladimir; Hadjiiska, Roumyana; Iaydjiev, Plamen; Marinov, Andrey; Piperov, Stefan; Rodozov, Mircho; Stoykova, Stefka; Sultanov, Georgi; Vutova, Mariana; Dimitrov, Anton; Glushkov, Ivan; Litov, Leander; Pavlov, Borislav; Petkov, Peicho; Bian, Jian-Guo; Chen, Guo-Ming; Chen, He-Sheng; Chen, Mingshui; Cheng, Tongguang; Du, Ran; Jiang, Chun-Hua; Plestina, Roko; Romeo, Francesco; Tao, Junquan; Wang, Zheng; Asawatangtrakuldee, Chayanit; Ban, Yong; Liu, Shuai; Mao, Yajun; Qian, Si-Jin; Wang, Dayong; Xu, Zijun; Zhang, Linlin; Zou, Wei; Avila, Carlos; Cabrera, Andrés; Chaparro Sierra, Luisa Fernanda; Florez, Carlos; Gomez, Juan Pablo; Gomez Moreno, Bernardo; Sanabria, Juan Carlos; Godinovic, Nikola; Lelas, Damir; Polic, Dunja; Puljak, Ivica; Antunovic, Zeljko; Kovac, Marko; Brigljevic, Vuko; Kadija, Kreso; Luetic, Jelena; Mekterovic, Darko; Sudic, Lucija; Attikis, Alexandros; Mavromanolakis, Georgios; Mousa, Jehad; Nicolaou, Charalambos; Ptochos, Fotios; Razis, Panos A; Rykaczewski, Hans; Bodlak, Martin; Finger, Miroslav; Finger Jr, Michael; Assran, Yasser; Ellithi Kamel, Ali; Mahmoud, Mohammed; Radi, Amr; Kadastik, Mario; Murumaa, Marion; Raidal, Martti; Tiko, Andres; Eerola, Paula; Voutilainen, Mikko; Härkönen, Jaakko; 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; Wendland, Lauri; Talvitie, Joonas; Tuuva, Tuure; Besancon, Marc; Couderc, Fabrice; Dejardin, Marc; Denegri, Daniel; Fabbro, Bernard; Faure, Jean-Louis; Favaro, Carlotta; Ferri, Federico; Ganjour, Serguei; Givernaud, Alain; Gras, Philippe; Hamel de Monchenault, Gautier; Jarry, Patrick; Locci, Elizabeth; Malcles, Julie; Rander, John; Rosowsky, André; Titov, Maksym; Baffioni, Stephanie; Beaudette, Florian; Busson, Philippe; Chapon, Emilien; Charlot, Claude; Dahms, Torsten; Dalchenko, Mykhailo; Dobrzynski, Ludwik; Filipovic, Nicolas; Florent, Alice; Granier de Cassagnac, Raphael; Mastrolorenzo, Luca; Miné, Philippe; Naranjo, Ivo Nicolas; Nguyen, Matthew; Ochando, Christophe; Ortona, Giacomo; Paganini, Pascal; Regnard, Simon; Salerno, Roberto; Sauvan, Jean-Baptiste; Sirois, Yves; Veelken, Christian; Yilmaz, Yetkin; Zabi, Alexandre; Agram, Jean-Laurent; Andrea, Jeremy; Aubin, Alexandre; Bloch, Daniel; Brom, Jean-Marie; Chabert, Eric Christian; Collard, Caroline; Conte, Eric; Fontaine, Jean-Charles; Gelé, Denis; Goerlach, Ulrich; Goetzmann, Christophe; Le Bihan, Anne-Catherine; Skovpen, Kirill; Van Hove, Pierre; Gadrat, Sébastien; Beauceron, Stephanie; Beaupere, Nicolas; Bernet, Colin; Boudoul, Gaelle; Bouvier, Elvire; Brochet, Sébastien; Carrillo Montoya, Camilo Andres; Chasserat, Julien; Chierici, Roberto; Contardo, Didier; Courbon, Benoit; Depasse, Pierre; El Mamouni, Houmani; Fan, Jiawei; Fay, Jean; Gascon, Susan; Gouzevitch, Maxime; Ille, Bernard; Kurca, Tibor; Lethuillier, Morgan; Mirabito, Laurent; Pequegnot, Anne-Laure; Perries, Stephane; Ruiz Alvarez, José David; Sabes, David; Sgandurra, Louis; Sordini, Viola; Vander Donckt, Muriel; Verdier, Patrice; Viret, Sébastien; Xiao, Hong; Tsamalaidze, Zviad; Autermann, Christian; Beranek, Sarah; Bontenackels, Michael; Edelhoff, Matthias; Feld, Lutz; Heister, Arno; Klein, Katja; Lipinski, Martin; Ostapchuk, Andrey; Preuten, Marius; Raupach, Frank; Sammet, Jan; Schael, Stefan; Schulte, Jan-Frederik; Weber, Hendrik; Wittmer, Bruno; Zhukov, Valery; Ata, Metin; Brodski, Michael; Dietz-Laursonn, Erik; Duchardt, Deborah; Erdmann, Martin; Fischer, Robert; Güth, Andreas; Hebbeker, Thomas; Heidemann, Carsten; Hoepfner, Kerstin; Klingebiel, Dennis; Knutzen, Simon; Kreuzer, Peter; Merschmeyer, Markus; Meyer, Arnd; Millet, Philipp; Olschewski, Mark; Padeken, Klaas; Papacz, Paul; Reithler, Hans; Schmitz, Stefan Antonius; Sonnenschein, Lars; Teyssier, Daniel; Thüer, Sebastian; Weber, Martin; Cherepanov, Vladimir; Erdogan, Yusuf; Flügge, Günter; Geenen, Heiko; Geisler, Matthias; Haj Ahmad, Wael; Hoehle, Felix; Kargoll, Bastian; Kress, Thomas; Kuessel, Yvonne; Künsken, Andreas; Lingemann, Joschka; Nowack, Andreas; Nugent, Ian Michael; Pooth, Oliver; Stahl, Achim; Aldaya Martin, Maria; Asin, Ivan; Bartosik, Nazar; Behr, Joerg; Behrens, Ulf; Bell, Alan James; Bethani, Agni; Borras, Kerstin; Burgmeier, Armin; Cakir, Altan; Calligaris, Luigi; Campbell, Alan; Choudhury, Somnath; Costanza, Francesco; Diez Pardos, Carmen; Dolinska, Ganna; Dooling, Samantha; Dorland, Tyler; Eckerlin, Guenter; Eckstein, Doris; Eichhorn, Thomas; Flucke, Gero; Garay Garcia, Jasone; Geiser, Achim; Gizhko, Andrii; Gunnellini, Paolo; Hauk, Johannes; Hempel, Maria; Jung, Hannes; Kalogeropoulos, Alexis; Karacheban, Olena; Kasemann, Matthias; Katsas, Panagiotis; Kieseler, Jan; Kleinwort, Claus; Korol, Ievgen; Krücker, Dirk; Lange, Wolfgang; Leonard, Jessica; Lipka, Katerina; Lobanov, Artur; Lohmann, Wolfgang; Lutz, Benjamin; Mankel, Rainer; Marfin, Ihar; Melzer-Pellmann, Isabell-Alissandra; Meyer, Andreas Bernhard; Mittag, Gregor; Mnich, Joachim; Mussgiller, Andreas; Naumann-Emme, Sebastian; Nayak, Aruna; Ntomari, Eleni; Perrey, Hanno; Pitzl, Daniel; Placakyte, Ringaile; Raspereza, Alexei; Ribeiro Cipriano, Pedro M; Roland, Benoit; Ron, Elias; Sahin, Mehmet Özgür; Salfeld-Nebgen, Jakob; Saxena, Pooja; Schoerner-Sadenius, Thomas; Schröder, Matthias; Seitz, Claudia; Spannagel, Simon; Vargas Trevino, Andrea Del Rocio; Walsh, Roberval; Wissing, Christoph; Blobel, Volker; Centis Vignali, Matteo; Draeger, Arne-Rasmus; Erfle, Joachim; Garutti, Erika; Goebel, Kristin; Görner, Martin; Haller, Johannes; Hoffmann, Malte; Höing, Rebekka Sophie; Junkes, Alexandra; Kirschenmann, Henning; Klanner, Robert; Kogler, Roman; Lapsien, Tobias; Lenz, Teresa; Marchesini, Ivan; Marconi, Daniele; Ott, Jochen; Peiffer, Thomas; Perieanu, Adrian; Pietsch, Niklas; Poehlsen, Jennifer; Pöhlsen, Thomas; Rathjens, Denis; Sander, Christian; Schettler, Hannes; Schleper, Peter; Schlieckau, Eike; Schmidt, Alexander; Seidel, Markus; Sola, Valentina; Stadie, Hartmut; Steinbrück, Georg; Troendle, Daniel; Usai, Emanuele; Vanelderen, Lukas; Vanhoefer, Annika; Barth, Christian; Baus, Colin; Berger, Joram; Böser, Christian; Butz, Erik; Chwalek, Thorsten; De Boer, Wim; Descroix, Alexis; Dierlamm, Alexander; Feindt, Michael; Frensch, Felix; Giffels, Manuel; Gilbert, Andrew; Hartmann, Frank; Hauth, Thomas; Husemann, Ulrich; Katkov, Igor; Kornmayer, Andreas; Lobelle Pardo, Patricia; Mozer, Matthias Ulrich; Müller, Thomas; Müller, Thomas; Nürnberg, Andreas; Quast, Gunter; Rabbertz, Klaus; Röcker, Steffen; Simonis, Hans-Jürgen; Stober, Fred-Markus Helmut; Ulrich, Ralf; Wagner-Kuhr, Jeannine; Wayand, Stefan; Weiler, Thomas; Wolf, Roger; Anagnostou, Georgios; Daskalakis, Georgios; Geralis, Theodoros; Giakoumopoulou, Viktoria Athina; Kyriakis, Aristotelis; Loukas, Demetrios; Markou, Athanasios; Markou, Christos; Psallidas, Andreas; Topsis-Giotis, Iasonas; Agapitos, Antonis; Kesisoglou, Stilianos; Panagiotou, Apostolos; Saoulidou, Niki; Stiliaris, Efstathios; Aslanoglou, Xenofon; Evangelou, Ioannis; Flouris, Giannis; Foudas, Costas; Kokkas, Panagiotis; Manthos, Nikolaos; Papadopoulos, Ioannis; Paradas, Evangelos; Strologas, John; Bencze, Gyorgy; Hajdu, Csaba; Hidas, Pàl; Horvath, Dezso; Sikler, Ferenc; Veszpremi, Viktor; Vesztergombi, Gyorgy; Zsigmond, Anna Julia; Beni, Noemi; Czellar, Sandor; Karancsi, János; Molnar, Jozsef; Palinkas, Jozsef; Szillasi, Zoltan; Makovec, Alajos; Raics, Peter; Trocsanyi, Zoltan Laszlo; Ujvari, Balazs; Swain, Sanjay Kumar; Beri, Suman Bala; Bhatnagar, Vipin; Gupta, Ruchi; Bhawandeep, Bhawandeep; Kalsi, Amandeep Kaur; Kaur, Manjit; Kumar, Ramandeep; Mittal, Monika; Nishu, Nishu; Singh, Jasbir; Kumar, Ashok; Kumar, Arun; Ahuja, Sudha; Bhardwaj, Ashutosh; Choudhary, Brajesh C; Kumar, Ajay; Malhotra, Shivali; Naimuddin, Md; Ranjan, Kirti; Sharma, Varun; Banerjee, Sunanda; Bhattacharya, Satyaki; Chatterjee, Kalyanmoy; Dutta, Suchandra; Gomber, Bhawna; Jain, Sandhya; Jain, Shilpi; Khurana, Raman; Modak, Atanu; Mukherjee, Swagata; Roy, Debarati; Sarkar, Subir; Sharan, Manoj; Abdulsalam, Abdulla; Dutta, Dipanwita; Kumar, Vineet; Mohanty, Ajit Kumar; Pant, Lalit Mohan; Shukla, Prashant; Topkar, Anita; Aziz, Tariq; Banerjee, Sudeshna; Bhowmik, Sandeep; Chatterjee, Rajdeep Mohan; Dewanjee, Ram Krishna; Dugad, Shashikant; Ganguly, Sanmay; Ghosh, Saranya; Guchait, Monoranjan; Gurtu, Atul; Kole, Gouranga; Kumar, Sanjeev; Maity, Manas; Majumder, Gobinda; Mazumdar, Kajari; Mohanty, Gagan Bihari; Parida, Bibhuti; Sudhakar, Katta; Wickramage, Nadeesha; Sharma, Seema; Bakhshiansohi, Hamed; Behnamian, Hadi; Etesami, Seyed Mohsen; Fahim, Ali; Goldouzian, Reza; Khakzad, Mohsen; Mohammadi Najafabadi, Mojtaba; Naseri, Mohsen; Paktinat Mehdiabadi, Saeid; Rezaei Hosseinabadi, Ferdos; Safarzadeh, Batool; Zeinali, Maryam; Felcini, Marta; Grunewald, Martin; Abbrescia, Marcello; Calabria, Cesare; Chhibra, Simranjit Singh; Colaleo, Anna; Creanza, Donato; Cristella, Leonardo; De Filippis, Nicola; De Palma, Mauro; Fiore, Luigi; Iaselli, Giuseppe; Maggi, Giorgio; Maggi, Marcello; My, Salvatore; Nuzzo, Salvatore; Pompili, Alexis; Pugliese, Gabriella; Radogna, Raffaella; Selvaggi, Giovanna; Sharma, Archana; Silvestris, Lucia; Venditti, Rosamaria; Verwilligen, Piet; Abbiendi, Giovanni; Benvenuti, Alberto; Bonacorsi, Daniele; Braibant-Giacomelli, Sylvie; Brigliadori, Luca; Campanini, Renato; Capiluppi, Paolo; Castro, Andrea; Cavallo, Francesca Romana; Codispoti, Giuseppe; Cuffiani, Marco; Dallavalle, Gaetano-Marco; Fabbri, Fabrizio; Fanfani, Alessandra; Fasanella, Daniele; Giacomelli, Paolo; Grandi, Claudio; Guiducci, Luigi; Marcellini, Stefano; Masetti, Gianni; Montanari, Alessandro; Navarria, Francesco; Perrotta, Andrea; Rossi, Antonio; Rovelli, Tiziano; Siroli, Gian Piero; Tosi, Nicolò; Travaglini, Riccardo; Albergo, Sebastiano; Cappello, Gigi; Chiorboli, Massimiliano; Costa, Salvatore; Giordano, Ferdinando; Potenza, Renato; Tricomi, Alessia; Tuve, Cristina; Barbagli, Giuseppe; Ciulli, Vitaliano; Civinini, Carlo; D'Alessandro, Raffaello; Focardi, Ettore; Gallo, Elisabetta; Gonzi, Sandro; Gori, Valentina; Lenzi, Piergiulio; Meschini, Marco; Paoletti, Simone; Sguazzoni, Giacomo; Tropiano, Antonio; Benussi, Luigi; Bianco, Stefano; Fabbri, Franco; Piccolo, Davide; Ferretti, Roberta; Ferro, Fabrizio; Lo Vetere, Maurizio; Robutti, Enrico; Tosi, Silvano; Dinardo, Mauro Emanuele; Fiorendi, Sara; Gennai, Simone; Gerosa, Raffaele; Ghezzi, Alessio; Govoni, Pietro; Lucchini, Marco Toliman; Malvezzi, Sandra; Manzoni, Riccardo Andrea; Martelli, Arabella; Marzocchi, Badder; Menasce, Dario; Moroni, Luigi; Paganoni, Marco; Pedrini, Daniele; Ragazzi, Stefano; Redaelli, Nicola; Tabarelli de Fatis, Tommaso; Buontempo, Salvatore; Cavallo, Nicola; Di Guida, Salvatore; Fabozzi, Francesco; Iorio, Alberto Orso Maria; Lista, Luca; Meola, Sabino; Merola, Mario; Paolucci, Pierluigi; Azzi, Patrizia; Bacchetta, Nicola; Bisello, Dario; Branca, Antonio; Carlin, Roberto; Checchia, Paolo; Dall'Osso, Martino; Dorigo, Tommaso; Dosselli, Umberto; Gasparini, Fabrizio; Gasparini, Ugo; Gozzelino, Andrea; Kanishchev, Konstantin; Lacaprara, Stefano; Margoni, Martino; Meneguzzo, Anna Teresa; Pazzini, Jacopo; Pozzobon, Nicola; Ronchese, Paolo; Simonetto, Franco; Torassa, Ezio; Tosi, Mia; Zotto, Pierluigi; Zucchetta, Alberto; Zumerle, Gianni; Gabusi, Michele; Ratti, Sergio P; Re, Valerio; Riccardi, Cristina; Salvini, Paola; Vitulo, Paolo; Biasini, Maurizio; Bilei, Gian Mario; Ciangottini, Diego; Fanò, Livio; Lariccia, Paolo; Mantovani, Giancarlo; Menichelli, Mauro; Saha, Anirban; Santocchia, Attilio; Spiezia, Aniello; Androsov, Konstantin; Azzurri, Paolo; Bagliesi, Giuseppe; Bernardini, Jacopo; Boccali, Tommaso; Broccolo, Giuseppe; Castaldi, Rino; Ciocci, Maria Agnese; Dell'Orso, Roberto; Donato, Silvio; Fedi, Giacomo; Fiori, Francesco; Foà, Lorenzo; Giassi, Alessandro; Grippo, Maria Teresa; Ligabue, Franco; Lomtadze, Teimuraz; Martini, Luca; Messineo, Alberto; Moon, Chang-Seong; Palla, Fabrizio; Rizzi, Andrea; Savoy-Navarro, Aurore; Serban, Alin Titus; Spagnolo, Paolo; Squillacioti, Paola; Tenchini, Roberto; Tonelli, Guido; Venturi, Andrea; Verdini, Piero Giorgio; Vernieri, Caterina; Barone, Luciano; Cavallari, Francesca; D'imperio, Giulia; Del Re, Daniele; Diemoz, Marcella; Jorda, Clara; Longo, Egidio; Margaroli, Fabrizio; Meridiani, Paolo; Micheli, Francesco; Organtini, Giovanni; Paramatti, Riccardo; Rahatlou, Shahram; Rovelli, Chiara; Santanastasio, Francesco; Soffi, Livia; Traczyk, Piotr; Amapane, Nicola; Arcidiacono, Roberta; Argiro, Stefano; Arneodo, Michele; Bellan, Riccardo; Biino, Cristina; Cartiglia, Nicolo; Casasso, Stefano; Costa, Marco; Covarelli, Roberto; Degano, Alessandro; Demaria, Natale; Finco, Linda; Mariotti, Chiara; Maselli, Silvia; Migliore, Ernesto; Monaco, Vincenzo; Musich, Marco; Obertino, Maria Margherita; Pacher, Luca; Pastrone, Nadia; Pelliccioni, Mario; Pinna Angioni, Gian Luca; Potenza, Alberto; Romero, Alessandra; Ruspa, Marta; Sacchi, Roberto; Solano, Ada; Staiano, Amedeo; Tamponi, Umberto; Belforte, Stefano; Candelise, Vieri; Casarsa, Massimo; Cossutti, Fabio; Della Ricca, Giuseppe; Gobbo, Benigno; La Licata, Chiara; Marone, Matteo; Schizzi, Andrea; Umer, Tomo; Zanetti, Anna; Chang, Sunghyun; Kropivnitskaya, Anna; Nam, Soon-Kwon; Kim, Dong Hee; Kim, Gui Nyun; Kim, Min Suk; Kong, Dae Jung; Lee, Sangeun; Oh, Young Do; Park, Hyangkyu; Sakharov, Alexandre; Son, Dong-Chul; Kim, Tae Jeong; Ryu, Min Sang; Kim, Jae Yool; Moon, Dong Ho; Song, Sanghyeon; Choi, Suyong; Gyun, Dooyeon; Hong, Byung-Sik; Jo, Mihee; Kim, Hyunchul; Kim, Yongsun; Lee, Byounghoon; Lee, Kyong Sei; Park, Sung Keun; Roh, Youn; Yoo, Hwi Dong; Choi, Minkyoo; Kim, Ji Hyun; Park, Inkyu; Ryu, Geonmo; Choi, Young-Il; Choi, Young Kyu; Goh, Junghwan; Kim, Donghyun; Kwon, Eunhyang; Lee, Jongseok; Yu, Intae; Juodagalvis, Andrius; Komaragiri, Jyothsna Rani; Md Ali, Mohd Adli Bin; Casimiro Linares, Edgar; Castilla-Valdez, Heriberto; De La Cruz-Burelo, Eduard; Heredia-de La Cruz, Ivan; Hernandez-Almada, Alberto; Lopez-Fernandez, Ricardo; Sánchez Hernández, Alberto; Carrillo Moreno, Salvador; Vazquez Valencia, Fabiola; Pedraza, Isabel; Salazar Ibarguen, Humberto Antonio; Morelos Pineda, Antonio; Krofcheck, David; Butler, Philip H; Reucroft, Steve; Ahmad, Ashfaq; Ahmad, Muhammad; Hassan, Qamar; Hoorani, Hafeez R; Khan, Wajid Ali; Khurshid, Taimoor; Shoaib, Muhammad; Bialkowska, Helena; Bluj, Michal; Boimska, Bożena; Frueboes, Tomasz; Górski, Maciej; Kazana, Malgorzata; Nawrocki, Krzysztof; Romanowska-Rybinska, Katarzyna; Szleper, Michal; Zalewski, Piotr; Brona, Grzegorz; Bunkowski, Karol; Cwiok, Mikolaj; Dominik, Wojciech; Doroba, Krzysztof; Kalinowski, Artur; Konecki, Marcin; Krolikowski, Jan; Misiura, Maciej; Olszewski, Michał; Bargassa, Pedrame; Beirão Da Cruz E Silva, Cristóvão; Faccioli, Pietro; Ferreira Parracho, Pedro Guilherme; Gallinaro, Michele; Lloret Iglesias, Lara; Nguyen, Federico; Rodrigues Antunes, Joao; Seixas, Joao; Varela, Joao; Vischia, Pietro; Bunin, Pavel; Golutvin, Igor; Gorbunov, Ilya; Karjavin, Vladimir; Konoplyanikov, Viktor; Kozlov, Guennady; Lanev, Alexander; Malakhov, Alexander; Matveev, Viktor; Moisenz, Petr; Palichik, Vladimir; Perelygin, Victor; Savina, Maria; Shmatov, Sergey; Shulha, Siarhei; Skatchkov, Nikolai; Smirnov, Vitaly; Zarubin, Anatoli; Golovtsov, Victor; Ivanov, Yury; Kim, Victor; Kuznetsova, Ekaterina; 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; Pashenkov, Anatoli; Tlisov, Danila; Toropin, Alexander; Epshteyn, Vladimir; Gavrilov, Vladimir; Lychkovskaya, Natalia; Popov, Vladimir; Pozdnyakov, Ivan; Safronov, Grigory; Semenov, Sergey; Spiridonov, Alexander; Stolin, Viatcheslav; Vlasov, Evgueni; Zhokin, Alexander; Andreev, Vladimir; Azarkin, Maksim; Dremin, Igor; Kirakosyan, Martin; Leonidov, Andrey; Mesyats, Gennady; Rusakov, Sergey V; Vinogradov, Alexey; Belyaev, Andrey; Boos, Edouard; Bunichev, Viacheslav; Dubinin, Mikhail; Dudko, Lev; Ershov, Alexander; Gribushin, Andrey; Klyukhin, Vyacheslav; Kodolova, Olga; Lokhtin, Igor; Obraztsov, Stepan; Savrin, Viktor; Snigirev, Alexander; Azhgirey, Igor; Bayshev, Igor; Bitioukov, Sergei; Kachanov, Vassili; Kalinin, Alexey; Konstantinov, Dmitri; Krychkine, Victor; Petrov, Vladimir; Ryutin, Roman; Sobol, Andrei; Tourtchanovitch, Leonid; Troshin, Sergey; Tyurin, Nikolay; Uzunian, Andrey; Volkov, Alexey; Adzic, Petar; Ekmedzic, Marko; Milosevic, Jovan; Rekovic, Vladimir; Alcaraz Maestre, Juan; Battilana, Carlo; Calvo, Enrique; Cerrada, Marcos; Chamizo Llatas, Maria; Colino, Nicanor; De La Cruz, Begona; Delgado Peris, Antonio; Domínguez Vázquez, Daniel; Escalante Del Valle, Alberto; Fernandez Bedoya, Cristina; Fernández Ramos, Juan Pablo; Flix, Jose; Fouz, Maria Cruz; Garcia-Abia, Pablo; Gonzalez Lopez, Oscar; Goy Lopez, Silvia; Hernandez, Jose M; Josa, Maria Isabel; Navarro De Martino, Eduardo; Pérez-Calero Yzquierdo, Antonio María; Puerta Pelayo, Jesus; Quintario Olmeda, Adrián; Redondo, Ignacio; Romero, Luciano; Soares, Mara Senghi; Albajar, Carmen; de Trocóniz, Jorge F; Missiroli, Marino; Moran, Dermot; Brun, Hugues; Cuevas, Javier; Fernandez Menendez, Javier; Folgueras, Santiago; Gonzalez Caballero, Isidro; Brochero Cifuentes, Javier Andres; Cabrillo, Iban Jose; Calderon, Alicia; Duarte Campderros, Jordi; Fernandez, Marcos; Gomez, Gervasio; Graziano, Alberto; Lopez Virto, Amparo; Marco, Jesus; Marco, Rafael; Martinez Rivero, Celso; Matorras, Francisco; Munoz Sanchez, Francisca Javiela; Piedra Gomez, Jonatan; Rodrigo, Teresa; Rodríguez-Marrero, Ana Yaiza; Ruiz-Jimeno, Alberto; Scodellaro, Luca; Vila, Ivan; Vilar Cortabitarte, Rocio; Abbaneo, Duccio; Auffray, Etiennette; Auzinger, Georg; Bachtis, Michail; Baillon, Paul; Ball, Austin; Barney, David; Benaglia, Andrea; Bendavid, Joshua; Benhabib, Lamia; Benitez, Jose F; Bloch, Philippe; Bocci, Andrea; Bonato, Alessio; Bondu, Olivier; Botta, Cristina; Breuker, Horst; Camporesi, Tiziano; Cerminara, Gianluca; Colafranceschi, Stefano; D'Alfonso, Mariarosaria; D'Enterria, David; Dabrowski, Anne; David Tinoco Mendes, Andre; De Guio, Federico; De Roeck, Albert; De Visscher, Simon; Di Marco, Emanuele; Dobson, Marc; Dordevic, Milos; Dorney, Brian; Dupont-Sagorin, Niels; Elliott-Peisert, Anna; Franzoni, Giovanni; Funk, Wolfgang; Gigi, Dominique; Gill, Karl; Giordano, Domenico; Girone, Maria; Glege, Frank; Guida, Roberto; Gundacker, Stefan; Guthoff, Moritz; Hammer, Josef; Hansen, Magnus; Harris, Philip; Hegeman, Jeroen; Innocente, Vincenzo; Janot, Patrick; Kousouris, Konstantinos; Krajczar, Krisztian; Lecoq, Paul; Lourenco, Carlos; Magini, Nicolo; Malgeri, Luca; Mannelli, Marcello; Marrouche, Jad; Masetti, Lorenzo; Meijers, Frans; Mersi, Stefano; Meschi, Emilio; Moortgat, Filip; Morovic, Srecko; Mulders, Martijn; Orsini, Luciano; Pape, Luc; Perez, Emmanuelle; Petrilli, Achille; Petrucciani, Giovanni; Pfeiffer, Andreas; Pimiä, Martti; Piparo, Danilo; Plagge, Michael; Racz, Attila; Rolandi, Gigi; Rovere, Marco; Sakulin, Hannes; Schäfer, Christoph; Schwick, Christoph; Sharma, Archana; Siegrist, Patrice; Silva, Pedro; Simon, Michal; Sphicas, Paraskevas; Spiga, Daniele; Steggemann, Jan; Stieger, Benjamin; Stoye, Markus; Takahashi, Yuta; Treille, Daniel; Tsirou, Andromachi; Veres, Gabor Istvan; Wardle, Nicholas; Wöhri, Hermine Katharina; Wollny, Heiner; Zeuner, Wolfram Dietrich; Bertl, Willi; Deiters, Konrad; Erdmann, Wolfram; Horisberger, Roland; Ingram, Quentin; Kaestli, Hans-Christian; Kotlinski, Danek; Langenegger, Urs; Renker, Dieter; Rohe, Tilman; Bachmair, Felix; Bäni, Lukas; Bianchini, Lorenzo; Buchmann, Marco-Andrea; Casal, Bruno; Chanon, Nicolas; Dissertori, Günther; Dittmar, Michael; Donegà, Mauro; Dünser, Marc; Eller, Philipp; Grab, Christoph; Hits, Dmitry; Hoss, Jan; Lustermann, Werner; Mangano, Boris; Marini, Andrea Carlo; Marionneau, Matthieu; Martinez Ruiz del Arbol, Pablo; Masciovecchio, Mario; Meister, Daniel; Mohr, Niklas; Musella, Pasquale; Nägeli, Christoph; Nessi-Tedaldi, Francesca; Pandolfi, Francesco; Pauss, Felicitas; Perrozzi, Luca; Peruzzi, Marco; Quittnat, Milena; Rebane, Liis; Rossini, Marco; Starodumov, Andrei; Takahashi, Maiko; Theofilatos, Konstantinos; Wallny, Rainer; Weber, Hannsjoerg Artur; Amsler, Claude; Canelli, Maria Florencia; Chiochia, Vincenzo; De Cosa, Annapaola; Hinzmann, Andreas; Hreus, Tomas; Kilminster, Benjamin; Lange, Clemens; Ngadiuba, Jennifer; Pinna, Deborah; Robmann, Peter; Ronga, Frederic Jean; Taroni, Silvia; Verzetti, Mauro; Yang, Yong; Cardaci, Marco; Chen, Kuan-Hsin; Ferro, Cristina; Kuo, Chia-Ming; Lin, Willis; Lu, Yun-Ju; Volpe, Roberta; Yu, Shin-Shan; Chang, Paoti; Chang, You-Hao; Chao, Yuan; Chen, Kai-Feng; Chen, Po-Hsun; Dietz, Charles; Grundler, Ulysses; Hou, George Wei-Shu; Liu, Yueh-Feng; Lu, Rong-Shyang; Miñano Moya, Mercedes; Petrakou, Eleni; Tzeng, Yeng-Ming; Wilken, Rachel; Asavapibhop, Burin; Singh, Gurpreet; Srimanobhas, Norraphat; Suwonjandee, Narumon; Adiguzel, Aytul; Bakirci, Mustafa Numan; Cerci, Salim; Dozen, Candan; Dumanoglu, Isa; Eskut, Eda; Girgis, Semiray; Gokbulut, Gul; Guler, Yalcin; Gurpinar, Emine; Hos, Ilknur; Kangal, Evrim Ersin; Kayis Topaksu, Aysel; Onengut, Gulsen; Ozdemir, Kadri; Ozturk, Sertac; Polatoz, Ayse; Sunar Cerci, Deniz; Tali, Bayram; Topakli, Huseyin; Vergili, Mehmet; Zorbilmez, Caglar; Akin, Ilina Vasileva; Bilin, Bugra; Bilmis, Selcuk; Gamsizkan, Halil; Isildak, Bora; Karapinar, Guler; Ocalan, Kadir; Sekmen, Sezen; Surat, Ugur Emrah; Yalvac, Metin; Zeyrek, Mehmet; Albayrak, Elif Asli; Gülmez, Erhan; Kaya, Mithat; Kaya, Ozlem; Yetkin, Taylan; Cankocak, Kerem; Vardarlı, Fuat Ilkehan; Levchuk, Leonid; Sorokin, Pavel; Brooke, James John; Clement, Emyr; Cussans, David; Flacher, Henning; Goldstein, Joel; Grimes, Mark; Heath, Greg P; Heath, Helen F; Jacob, Jeson; Kreczko, Lukasz; Lucas, Chris; Meng, Zhaoxia; Newbold, Dave M; Paramesvaran, Sudarshan; Poll, Anthony; Sakuma, Tai; Seif El Nasr-storey, Sarah; Senkin, Sergey; Smith, Vincent J; Bell, Ken W; Belyaev, Alexander; Brew, Christopher; Brown, Robert M; Cockerill, David JA; Coughlan, John A; Harder, Kristian; Harper, Sam; Olaiya, Emmanuel; Petyt, David; Shepherd-Themistocleous, Claire; Thea, Alessandro; Tomalin, Ian R; Williams, Thomas; Womersley, William John; Worm, Steven; Baber, Mark; Bainbridge, Robert; Buchmuller, Oliver; Burton, Darren; Colling, David; Cripps, Nicholas; Dauncey, Paul; Davies, Gavin; Della Negra, Michel; Dunne, Patrick; Elwood, Adam; Ferguson, William; Fulcher, Jonathan; Futyan, David; Hall, Geoffrey; Iles, Gregory; Jarvis, Martyn; Karapostoli, Georgia; Kenzie, Matthew; Lane, Rebecca; Lucas, Robyn; Lyons, Louis; Magnan, Anne-Marie; Malik, Sarah; Mathias, Bryn; Nash, Jordan; Nikitenko, Alexander; Pela, Joao; Pesaresi, Mark; Petridis, Konstantinos; Raymond, David Mark; Rogerson, Samuel; Rose, Andrew; Seez, Christopher; Sharp, Peter; Tapper, Alexander; Vazquez Acosta, Monica; Virdee, Tejinder; Zenz, Seth Conrad; Cole, Joanne; Hobson, Peter R; Khan, Akram; Kyberd, Paul; Leggat, Duncan; Leslie, Dawn; Reid, Ivan; Symonds, Philip; Teodorescu, Liliana; Turner, Mark; Dittmann, Jay; Hatakeyama, Kenichi; Kasmi, Azeddine; Liu, Hongxuan; Pastika, Nathaniel; Scarborough, Tara; Wu, Zhenbin; Charaf, Otman; Cooper, Seth; Henderson, Conor; Rumerio, Paolo; Avetisyan, Aram; Bose, Tulika; Fantasia, Cory; Lawson, Philip; Richardson, Clint; Rohlf, James; St John, Jason; Sulak, Lawrence; Alimena, Juliette; Berry, Edmund; Bhattacharya, Saptaparna; Christopher, Grant; Cutts, David; Demiragli, Zeynep; Dhingra, Nitish; Ferapontov, Alexey; Garabedian, Alex; Heintz, Ulrich; Kukartsev, Gennadiy; Laird, Edward; Landsberg, Greg; Luk, Michael; Narain, Meenakshi; Segala, Michael; Sinthuprasith, Tutanon; Speer, Thomas; Swanson, Joshua; Breedon, Richard; Breto, Guillermo; Calderon De La Barca Sanchez, Manuel; Chauhan, Sushil; Chertok, Maxwell; Conway, John; Conway, Rylan; Cox, Peter Timothy; Erbacher, Robin; Gardner, Michael; Ko, Winston; Lander, Richard; Mulhearn, Michael; Pellett, Dave; Pilot, Justin; Ricci-Tam, Francesca; Shalhout, Shalhout; Smith, John; Squires, Michael; Stolp, Dustin; Tripathi, Mani; Wilbur, Scott; Yohay, Rachel; Cousins, Robert; Everaerts, Pieter; Farrell, Chris; Hauser, Jay; Ignatenko, Mikhail; Rakness, Gregory; Takasugi, Eric; Valuev, Vyacheslav; Weber, Matthias; Burt, Kira; Clare, Robert; Ellison, John Anthony; Gary, J William; Hanson, Gail; Heilman, Jesse; Ivova Rikova, Mirena; Jandir, Pawandeep; Kennedy, Elizabeth; Lacroix, Florent; Long, Owen Rosser; Luthra, Arun; Malberti, Martina; Olmedo Negrete, Manuel; Shrinivas, Amithabh; Sumowidagdo, Suharyo; Wimpenny, Stephen; Branson, James G; Cerati, Giuseppe Benedetto; Cittolin, Sergio; D'Agnolo, Raffaele Tito; Holzner, André; Kelley, Ryan; Klein, Daniel; Letts, James; Macneill, Ian; Olivito, Dominick; Padhi, Sanjay; Palmer, Christopher; Pieri, Marco; Sani, Matteo; Sharma, Vivek; Simon, Sean; Tadel, Matevz; Tu, Yanjun; Vartak, Adish; Welke, Charles; Würthwein, Frank; Yagil, Avraham; Zevi Della Porta, Giovanni; Barge, Derek; Bradmiller-Feld, John; Campagnari, Claudio; Danielson, Thomas; Dishaw, Adam; Dutta, Valentina; Flowers, Kristen; Franco Sevilla, Manuel; Geffert, Paul; George, Christopher; Golf, Frank; Gouskos, Loukas; Incandela, Joe; Justus, Christopher; Mccoll, Nickolas; Mullin, Sam Daniel; Richman, Jeffrey; Stuart, David; To, Wing; West, Christopher; Yoo, Jaehyeok; Apresyan, Artur; Bornheim, Adolf; Bunn, Julian; Chen, Yi; Duarte, Javier; Mott, Alexander; Newman, Harvey B; Pena, Cristian; Pierini, Maurizio; Spiropulu, Maria; Vlimant, Jean-Roch; Wilkinson, Richard; Xie, Si; Zhu, Ren-Yuan; Azzolini, Virginia; Calamba, Aristotle; Carlson, Benjamin; Ferguson, Thomas; Iiyama, Yutaro; Paulini, Manfred; Russ, James; Vogel, Helmut; Vorobiev, Igor; Cumalat, John Perry; Ford, William T; Gaz, Alessandro; Krohn, Michael; Luiggi Lopez, Eduardo; Nauenberg, Uriel; Smith, James; Stenson, Kevin; Wagner, Stephen Robert; Alexander, James; Chatterjee, Avishek; Chaves, Jorge; Chu, Jennifer; Dittmer, Susan; Eggert, Nicholas; Mirman, Nathan; Nicolas Kaufman, Gala; Patterson, Juliet Ritchie; Ryd, Anders; Salvati, Emmanuele; Skinnari, Louise; Sun, Werner; Teo, Wee Don; Thom, Julia; Thompson, Joshua; Tucker, Jordan; Weng, Yao; Winstrom, Lucas; Wittich, Peter; Winn, Dave; Abdullin, Salavat; Albrow, Michael; Anderson, Jacob; Apollinari, Giorgio; Bauerdick, Lothar AT; Beretvas, Andrew; Berryhill, Jeffrey; Bhat, Pushpalatha C; Bolla, Gino; Burkett, Kevin; Butler, Joel Nathan; Cheung, Harry; Chlebana, Frank; Cihangir, Selcuk; Elvira, Victor Daniel; Fisk, Ian; Freeman, Jim; Gottschalk, Erik; Gray, Lindsey; Green, Dan; Grünendahl, Stefan; Gutsche, Oliver; Hanlon, Jim; Hare, Daryl; Harris, Robert M; Hirschauer, James; Hooberman, Benjamin; Jindariani, Sergo; Johnson, Marvin; Joshi, Umesh; Klima, Boaz; Kreis, Benjamin; Kwan, Simon; Linacre, Jacob; Lincoln, Don; Lipton, Ron; Liu, Tiehui; Lykken, Joseph; Maeshima, Kaori; Marraffino, John Michael; Martinez Outschoorn, Verena Ingrid; Maruyama, Sho; Mason, David; McBride, Patricia; Merkel, Petra; Mishra, Kalanand; Mrenna, Stephen; Nahn, Steve; Newman-Holmes, Catherine; O'Dell, Vivian; Prokofyev, Oleg; Sexton-Kennedy, Elizabeth; Soha, Aron; Spalding, William J; Spiegel, Leonard; Taylor, Lucas; Tkaczyk, Slawek; Tran, Nhan Viet; Uplegger, Lorenzo; Vaandering, Eric Wayne; Vidal, Richard; Whitbeck, Andrew; Whitmore, Juliana; Yang, Fan; Acosta, Darin; Avery, Paul; Bortignon, Pierluigi; Bourilkov, Dimitri; Carver, Matthew; Curry, David; Das, Souvik; De Gruttola, Michele; Di Giovanni, Gian Piero; Field, Richard D; Fisher, Matthew; Furic, Ivan-Kresimir; Hugon, Justin; Konigsberg, Jacobo; Korytov, Andrey; Kypreos, Theodore; Low, Jia Fu; Matchev, Konstantin; Mei, Hualin; Milenovic, Predrag; Mitselmakher, Guenakh; Muniz, Lana; Rinkevicius, Aurelijus; Shchutska, Lesya; Snowball, Matthew; Sperka, David; Yelton, John; Zakaria, Mohammed; Hewamanage, Samantha; Linn, Stephan; Markowitz, Pete; Martinez, German; Rodriguez, Jorge Luis; Adams, Jordon Rowe; Adams, Todd; Askew, Andrew; Bochenek, Joseph; Diamond, Brendan; Haas, Jeff; Hagopian, Sharon; Hagopian, Vasken; Johnson, Kurtis F; Prosper, Harrison; Veeraraghavan, Venkatesh; Weinberg, Marc; Baarmand, Marc M; Hohlmann, Marcus; Kalakhety, Himali; Yumiceva, Francisco; Adams, Mark Raymond; Apanasevich, Leonard; Berry, Douglas; Betts, Russell Richard; Bucinskaite, Inga; Cavanaugh, Richard; Evdokimov, Olga; Gauthier, Lucie; Gerber, Cecilia Elena; Hofman, David Jonathan; Kurt, Pelin; O'Brien, Christine; Sandoval Gonzalez, Irving Daniel; Silkworth, Christopher; Turner, Paul; Varelas, Nikos; Bilki, Burak; Clarida, Warren; Dilsiz, Kamuran; Haytmyradov, Maksat; Merlo, Jean-Pierre; Mermerkaya, Hamit; Mestvirishvili, Alexi; Moeller, Anthony; Nachtman, Jane; Ogul, Hasan; Onel, Yasar; Ozok, Ferhat; Penzo, Aldo; Rahmat, Rahmat; Sen, Sercan; Tan, Ping; Tiras, Emrah; Wetzel, James; Yi, Kai; Anderson, Ian; Barnett, Bruce Arnold; Blumenfeld, Barry; Bolognesi, Sara; Fehling, David; Gritsan, Andrei; Maksimovic, Petar; Martin, Christopher; Swartz, Morris; Xiao, Meng; Baringer, Philip; Bean, Alice; Benelli, Gabriele; Bruner, Christopher; Gray, Julia; Kenny III, Raymond Patrick; Majumder, Devdatta; Malek, Magdalena; Murray, Michael; Noonan, Daniel; Sanders, Stephen; Sekaric, Jadranka; Stringer, Robert; Wang, Quan; Wood, Jeffrey Scott; Chakaberia, Irakli; Ivanov, Andrew; Kaadze, Ketino; Khalil, Sadia; Makouski, Mikhail; Maravin, Yurii; Saini, Lovedeep Kaur; Skhirtladze, Nikoloz; Svintradze, Irakli; Gronberg, Jeffrey; Lange, David; Rebassoo, Finn; Wright, Douglas; Baden, Drew; Belloni, Alberto; Calvert, Brian; Eno, Sarah Catherine; Gomez, Jaime; Hadley, Nicholas John; Jabeen, Shabnam; Kellogg, Richard G; Kolberg, Ted; Lu, Ying; Mignerey, Alice; Pedro, Kevin; Skuja, Andris; Tonjes, Marguerite; Tonwar, Suresh C; Apyan, Aram; Barbieri, Richard; Bierwagen, Katharina; Busza, Wit; Cali, Ivan Amos; Di Matteo, Leonardo; Gomez Ceballos, Guillelmo; Goncharov, Maxim; Gulhan, Doga; Klute, Markus; Lai, Yue Shi; Lee, Yen-Jie; Levin, Andrew; Luckey, Paul David; Paus, Christoph; Ralph, Duncan; Roland, Christof; Roland, Gunther; Stephans, George; Sumorok, Konstanty; Velicanu, Dragos; Veverka, Jan; Wyslouch, Bolek; Yang, Mingming; Zanetti, Marco; Zhukova, Victoria; Dahmes, Bryan; Gude, Alexander; Kao, Shih-Chuan; Klapoetke, Kevin; Kubota, Yuichi; Mans, Jeremy; Nourbakhsh, Shervin; Rusack, Roger; Singovsky, Alexander; Tambe, Norbert; Turkewitz, Jared; Acosta, John Gabriel; Oliveros, Sandra; Avdeeva, Ekaterina; Bloom, Kenneth; Bose, Suvadeep; Claes, Daniel R; Dominguez, Aaron; Gonzalez Suarez, Rebeca; Keller, Jason; Knowlton, Dan; Kravchenko, Ilya; Lazo-Flores, Jose; Meier, Frank; Ratnikov, Fedor; Snow, Gregory R; Zvada, Marian; Dolen, James; Godshalk, Andrew; Iashvili, Ia; Kharchilava, Avto; Kumar, Ashish; Rappoccio, Salvatore; Alverson, George; Barberis, Emanuela; Baumgartel, Darin; Chasco, Matthew; Massironi, Andrea; Morse, David Michael; Nash, David; Orimoto, Toyoko; Trocino, Daniele; Wang, Ren-Jie; Wood, Darien; Zhang, Jinzhong; Hahn, Kristan Allan; Kubik, Andrew; Mucia, Nicholas; Odell, Nathaniel; Pollack, Brian; Pozdnyakov, Andrey; Schmitt, Michael; Stoynev, Stoyan; Sung, Kevin; Velasco, Mayda; Won, Steven; Brinkerhoff, Andrew; Chan, Kwok Ming; Drozdetskiy, Alexey; Hildreth, Michael; Jessop, Colin; Karmgard, Daniel John; Kellams, Nathan; Lannon, Kevin; Lynch, Sean; Marinelli, Nancy; Musienko, Yuri; Pearson, Tessa; Planer, Michael; Ruchti, Randy; Smith, Geoffrey; Valls, Nil; Wayne, Mitchell; Wolf, Matthias; Woodard, Anna; Antonelli, Louis; Brinson, Jessica; Bylsma, Ben; Durkin, Lloyd Stanley; Flowers, Sean; Hart, Andrew; Hill, Christopher; Hughes, Richard; Kotov, Khristian; Ling, Ta-Yung; Luo, Wuming; Puigh, Darren; Rodenburg, Marissa; Winer, Brian L; Wolfe, Homer; Wulsin, Howard Wells; Driga, Olga; Elmer, Peter; Hardenbrook, Joshua; Hebda, Philip; Koay, Sue Ann; Lujan, Paul; Marlow, Daniel; Medvedeva, Tatiana; Mooney, Michael; Olsen, James; Piroué, Pierre; Quan, Xiaohang; Saka, Halil; Stickland, David; Tully, Christopher; Werner, Jeremy Scott; Zuranski, Andrzej; Brownson, Eric; Malik, Sudhir; Mendez, Hector; Ramirez Vargas, Juan Eduardo; Barnes, Virgil E; Benedetti, Daniele; Bortoletto, Daniela; De Mattia, Marco; Gutay, Laszlo; Hu, Zhen; Jha, Manoj; Jones, Matthew; Jung, Kurt; Kress, Matthew; Leonardo, Nuno; Miller, David Harry; Neumeister, Norbert; Primavera, Federica; Radburn-Smith, Benjamin Charles; Shi, Xin; Shipsey, Ian; Silvers, David; Svyatkovskiy, Alexey; Wang, Fuqiang; Xie, Wei; Xu, Lingshan; Zablocki, Jakub; Parashar, Neeti; Stupak, John; Adair, Antony; Akgun, Bora; Ecklund, Karl Matthew; Geurts, Frank J M; Li, Wei; Michlin, Benjamin; Padley, Brian Paul; Redjimi, Radia; Roberts, Jay; Zabel, James; Betchart, Burton; Bodek, Arie; de Barbaro, Pawel; Demina, Regina; Eshaq, Yossof; Ferbel, Thomas; Galanti, Mario; Garcia-Bellido, Aran; Goldenzweig, Pablo; Han, Jiyeon; Harel, Amnon; Hindrichs, Otto; Khukhunaishvili, Aleko; Korjenevski, Sergey; Petrillo, Gianluca; Vishnevskiy, Dmitry; Ciesielski, Robert; Demortier, Luc; Goulianos, Konstantin; Mesropian, Christina; Arora, Sanjay; Barker, Anthony; Chou, John Paul; Contreras-Campana, Christian; Contreras-Campana, Emmanuel; Duggan, Daniel; Ferencek, Dinko; Gershtein, Yuri; Gray, Richard; Halkiadakis, Eva; Hidas, Dean; Kaplan, Steven; Lath, Amitabh; Panwalkar, Shruti; Park, Michael; Patel, Rishi; Salur, Sevil; Schnetzer, Steve; Sheffield, David; Somalwar, Sunil; Stone, Robert; Thomas, Scott; Thomassen, Peter; Walker, Matthew; Rose, Keith; Spanier, Stefan; York, Andrew; Bouhali, Othmane; Castaneda Hernandez, Alfredo; Eusebi, Ricardo; Flanagan, Will; Gilmore, Jason; Kamon, Teruki; Khotilovich, Vadim; Krutelyov, Vyacheslav; Montalvo, Roy; Osipenkov, Ilya; Pakhotin, Yuriy; Perloff, Alexx; Roe, Jeffrey; Rose, Anthony; Safonov, Alexei; Suarez, Indara; Tatarinov, Aysen; Ulmer, Keith; Akchurin, Nural; Cowden, Christopher; Damgov, Jordan; Dragoiu, Cosmin; Dudero, Phillip Russell; Faulkner, James; Kovitanggoon, Kittikul; Kunori, Shuichi; Lee, Sung Won; Libeiro, Terence; Volobouev, Igor; Appelt, Eric; Delannoy, Andrés G; Greene, Senta; Gurrola, Alfredo; Johns, Willard; Maguire, Charles; Mao, Yaxian; Melo, Andrew; Sharma, Monika; Sheldon, Paul; Snook, Benjamin; Tuo, Shengquan; Velkovska, Julia; Arenton, Michael Wayne; Boutle, Sarah; Cox, Bradley; Francis, Brian; Goodell, Joseph; Hirosky, Robert; Ledovskoy, Alexander; Li, Hengne; Lin, Chuanzhe; Neu, Christopher; Wolfe, Evan; Wood, John; Clarke, Christopher; Harr, Robert; Karchin, Paul Edmund; Kottachchi Kankanamge Don, Chamath; Lamichhane, Pramod; Sturdy, Jared; Belknap, Donald; Carlsmith, Duncan; Cepeda, Maria; Dasu, Sridhara; Dodd, Laura; Duric, Senka; Friis, Evan; Hall-Wilton, Richard; Herndon, Matthew; Hervé, Alain; Klabbers, Pamela; Lanaro, Armando; Lazaridis, Christos; Levine, Aaron; Loveless, Richard; Mohapatra, Ajit; Ojalvo, Isabel; Perry, Thomas; Pierro, Giuseppe Antonio; Polese, Giovanni; Ross, Ian; Sarangi, Tapas; Savin, Alexander; Smith, Wesley H; Taylor, Devin; Vuosalo, Carl; Woods, Nathaniel
2015-01-01
A search is performed for a vector-like heavy T quark that is produced in pairs and that decays to a top quark and a Higgs boson. The data analysed correspond to an integrated luminosity of 19.7 fb$^{-1}$ collected with the CMS detector in proton-proton collisions at $\\sqrt{s}$ = 8 TeV. For T quarks with large mass values the top quarks and Higgs bosons can have significant Lorentz boosts, so that their individual decay products often overlap and merge. Methods are applied to resolve the substructure of such merged jets. Upper limits on the production cross section of a T quark with mass between 500 and 1000 GeV/$c^2$ are derived. If the T quark decays exclusively to tH, the observed (expected) lower limit on the mass of the T quark is 745 (773) GeV/$c^2$ at 95% confidence level. For the first time an algorithm is used for tagging boosted Higgs bosons that is based on a combination of jet substructure information and b tagging.
Wigner distributions and quark orbital angular momentum
Cedric LorceOrsay, IPN and Orsay, LPT; Barbara Pasquini(Pavia U. and INFN, Pavia)
2015-01-01
We discuss the quark phase-space or Wigner distributions of the nucleon which combine in a single picture all the information contained in the generalized parton distributions and the transverse-momentum dependent parton distributions. In particular, we present results for the distribution of unpolarized quarks in a longitudinally polarized nucleon obtained in a light-front constituent quark model. We show how the quark orbital angular momentum can be extracted from the Wigner distributions a...
Discovery of single top quark production
Gillberg, Dag
2009-01-01
The top quark is by far the heaviest known fundamental particle with a mass nearing that of a gold atom. Because of this strikingly high mass, the top quark has several unique properties and might play an important role in electroweak symmetry breaking—the mechanism that gives all elementary particles mass. Creating top quarks requires access to very high energy collisions, and at present only the Tevatron collider at Fermilab is capable of reaching these energies. Until now, top quarks have ...
Heavy Quark Energy Loss in Nuclear Medium
Zhang, Benr-Wei; Wang, Enke; Wang, Xin-Nian
2003-01-01
Multiple scattering, modified fragmentation functions and radiative energy loss of a heavy quark propagating in a nuclear medium are investigated in perturbative QCD. Because of the quark mass dependence of the gluon formation time, the medium size dependence of heavy quark energy loss is found to change from a linear to a quadratic form when the initial energy and momentum scale are increased relative to the quark mass. The radiative energy loss is also significantly suppressed relative to a...
Energy Density in Quark-Gluon Plasma
Institute of Scientific and Technical Information of China (English)
马忠彪; 苗洪; 高崇寿
2003-01-01
We study the energy density in quark-gluon plasma. At the very high temperature, the quark matter is a hot and dense matter in the colour deconfinement condition, and quarks can coalescent diquarks. Energy density of this system is worked out and compared with the energy density in the other two kinds of situations. Possible energy density is about eo ≈ 2.4 GeV/fm3 according to our estimation for quark matter including diquarks,
Deep-inelastic production of heavy quarks
Laenen, E.; Buza, M.; Harris, B. W.; Matiounine, Y.; Migneron, R.; Riemersma, S.; Smith, J.; van Neerven, W. L.
1996-01-01
Deep-inelastic production of heavy quarks at HERA, especially charm, is an excellent signal to measure the gluon distribution in the proton at small $x$ values. By measuring various differential distributions of the heavy quarks this reaction permits additional more incisive QCD analyses due to the many scales present. Furthermore, the relatively small mass of the charm quark, compared to the typical momentum transfer $Q$, allows one to study whether and when to treat this quark as a parton. ...
Heavy Quark Dynamics in Heavy Ion Reactions
Nagle, J. L.
2003-01-01
Collisions between heavy nuclei at the Relativistic Heavy Ion Collider liberate from the nuclear wavefunction of order 10,000 gluons, quarks and antiquarks. The system is dominated by gluons and up and down (anti) quarks. Heavy quarks, though having little effect on the overall equation of state, are critical as probes of the surrounding medium. We compare predictions from a scenario where the charm quarks escape the medium unaffected and fragment into hadrons in vacuum, and one where the cha...
Light Quark Spin-Flavor Symmetry for Baryons Containing a Heavy Quark in Large N QCD
Jenkins, E
1993-01-01
The couplings and interactions of baryons containing a heavy quark are related by light quark spin-flavor symmetry in the large $N$ limit. The single pion coupling constant which determines all heavy quark baryon-pion couplings is equal to the pion coupling constant for light quark baryons. Light quark symmetry relations amongst the baryon couplings are violated at order $1/N^2$. Heavy quark spin-flavor symmetry is used in conjunction with large $N$ light quark spin-flavor symmetry to determi...
Quarks, baryons and chiral symmetry
Hosaka, Atsushi
2001-01-01
This book describes baryon models constructed from quarks, mesons and chiral symmetry. The role of chiral symmetry and of quark model structure with SU(6) spin-flavor symmetry are discussed in detail, starting from a pedagogic introduction. Emphasis is placed on symmetry aspects of the theories. As an application, the chiral bag model is studied for nucleon structure, where important methods of theoretical physics, mostly related to the semiclassical approach for a system of strong interactions, are demonstrated. The text is more practical than formal; tools and ideas are explained in detail w
International Nuclear Information System (INIS)
After a short reminder of the historical role of the quark model as an ancestor of QCD we discuss some of its old and recent achievements and its limitations. We first outline the rather successful description of electroweak hadronic matrix elements, and of strong decays. We also discuss its theoretical weaknesses (non relativistic hypothesis, difficulty to describe Goldstone bosons ...). We stress that in some fields it remains the only phenomelogical tool: High order hadronic phenomena, process involving excited hadrons, etc. Finally we exhibit cases in which the successes of the quark model can be understood by more rigorous proofs of the same results. (orig.)
Experimental methods of heavy quark detection
International Nuclear Information System (INIS)
By comparing how b and c were observed we saw that the heavier quark was more difficult to detect. For various reasons the signal was smaller and the signal-to-noise worse. This trend is expected to continue when searching for the still heavier top quark. In fact many detection techniques which worked well for bottom and charm are not viable for top. For masses less than about 60 GeV/c2 top should be visible at the CERN S anti ppS. For larger masses the higher energy of the Fermilab Tevatron will be necessary. At both machines semileptonic decays are the most promising tag. There are background rejection techniques which should result in a fairly clean signal. As there are many possible background sources it is important to carefully estimate the residual background from the data itself. At e+e- machines top will be copiously produced in Z0 decays if M/sub t/ 0//2. In this case it is possible to estimate its mass and study its decay modes. 40 references, 40 figures
Experimental methods of heavy quark detection
Energy Technology Data Exchange (ETDEWEB)
Himel, T.
1984-11-01
By comparing how b and c were observed we saw that the heavier quark was more difficult to detect. For various reasons the signal was smaller and the signal-to-noise worse. This trend is expected to continue when searching for the still heavier top quark. In fact many detection techniques which worked well for bottom and charm are not viable for top. For masses less than about 60 GeV/c/sup 2/ top should be visible at the CERN S anti ppS. For larger masses the higher energy of the Fermilab Tevatron will be necessary. At both machines semileptonic decays are the most promising tag. There are background rejection techniques which should result in a fairly clean signal. As there are many possible background sources it is important to carefully estimate the residual background from the data itself. At e/sup +/e/sup -/ machines top will be copiously produced in Z/sup 0/ decays if M/sub t/ < M/sub Z/sup 0///2. In this case it is possible to estimate its mass and study its decay modes. 40 references, 40 figures.
Heavy quark physics in ep collisions at LEP+LHC
International Nuclear Information System (INIS)
We study electroweak production of heavy quarks - charm, beauty, and top - in deep inelastic electron-proton collisions at the proposed LEP+LHC collider at CERN. The assumed energy for the collisions is Ee=50 GeV, Ep=8000 GeV, providing an ep center of mass energy, √s≅1.26 TeV. We invoke the boson-gluon fusion model to estimate theoretical cross sections and distributions for the heavy quarks. Higher order QCD corrections are only approximately taken into account, by assuming a (normalization) K-factor of 2 for the charm and beauty quark production rates and incorporating the parton shower cascades. With these assumptions and the parameterization of Eichten et al. for the structure functions (EHLQ, set 1), we find the following cross sections: σ(ep→c+X)≅O(3 μb), σ(ep→b+X)≅O(40 nb), and σ(ep→t+X)≅4 pb for mt=120 GeV, decreasing to 0.5 pb for mt=250 GeV. These cross sections would provide O(6x109) charmed hadrons, O(8x107) beauty hadrons, and O(103) top hadrons, for an integrated ep luminosity of 1000 pb-1. The heavy quark rates in ep collisions are considerably smaller than the corresponding rates in pp collisions at LHC, with √s=16 TeV. This gives a clear advantage to pp collisions for top searches. However, for the charmed and beauty quarks only a tiny fraction of the cross sections in p+p→Q+X can be triggered in comparison to the corresponding cross sections in e+p→Q+X, resulting in comparable number of measured heavy quark events in the ep and pp mode. We sketch the energy-momentum profile of heavy quark events in ep collisions and illustrate the kind of analyses that experiments at the LEP+LHC collider would undertake to quantitatively study heavy quark physics. In particular, prospects of measuring the particle-antiparticle mixing parameter xs=ΔM/Γ for the Bs0-anti Bs0 meson system are evaluated, and search strategies for the top quark in ep collisions are presented. (orig.)
''Follow that quark!'' (and other exclusive stories)
International Nuclear Information System (INIS)
Quarks are considered to be the basic constituents of matter. In a series of recent experiments, Carroll studied exclusive reactions as a means of determining the interactions between quarks. Quantum Chromo-dynamics (QCD) is the modern theory of the interaction of quarks. This theory explains how quarks are held together via the strong interaction in particles known as hadrons. Hadrons consisting of three quarks are called baryons. Hadrons made up of a quark and an antiquark are called mesons. In his lecture, Carroll describes what happens when two hadrons collide and scatter to large angles. The violence of the collision causes the gluons that bind the quarks in a particular hadron to temporarily lose their grip on particular quarks. Quarks scramble toward renewed unity with other quarks, and they undergo rearrangement, which generally results in additional new particles. A two-body exclusive reaction has occurred when the same number of particles exist before and after the collisions. At large angles these exclusive reactions are very rare. The labels on the quarks known as flavor enable the experimenter to follow the history of individual quarks in detail during these exclusive reactions. Carroll describes the equipment used in the experiment to measure short distance, hard collisions at large angles. The collisions he discusses occur when a known beam of mesons or protons collide with a stationary proton target. Finally, Carroll summarizes what the experiments have shown from the study of exclusive reactions and what light some of their results shed on the theory of QCD
Some aspects of three-quark potentials
Andreev, Oleg
2016-05-01
We analytically evaluate the expectation value of a baryonic Wilson loop in a holographic model of an S U (3 ) pure gauge theory. We then discuss three aspects of a static three-quark potential: an aspect of universality which concerns properties independent of a geometric configuration of quarks, a heavy diquark structure, and a relation between the three- and two-quark potentials.
Hyperon polarization in the constituent quark model
International Nuclear Information System (INIS)
A mechanism for hyperon polarization in the inclusive production is considered. The main role belongs to the orbital angular momentum and polarization of strange quark-antiquark pairs in the internal structure of constituent quarks. The nonperturbative hadron structure is based on the results of chiral quark models
SPONTANEOUS CP VIOLATION AND QUARK MASS AMBIGUITIES.
Energy Technology Data Exchange (ETDEWEB)
CREUTZ,M.
2004-09-21
I explore the regions of quark masses where CP will be spontaneously broken in the strong interactions. The boundaries of these regions are controlled by the chiral anomaly, which manifests itself in ambiguities in the definition of non-degenerate quark masses. In particular, the concept of a single massless quark is ill defined.
Quark fragmentation in e+e- collisions
International Nuclear Information System (INIS)
This brief review of new results in quark and gluon fragmentation observed in e+e- collisions concentrates mostly on PEP results and, within PEP, mostly on TPC results. The new PETRA results have been reported at this conference by M. Davier. It is restricted to results on light quark fragmentation since the results on heavy quark fragmentation have been reported by J. Chapman
Charm-quarks and new elementary particles
International Nuclear Information System (INIS)
This is the first part of an extensive paper which discusses: the Nobel prize in physics 1976; discovery of the J/psi-particle; elementary particles and elementary building blocks; the four reciprocal effects; gauge theories; quark-antiquark reciprocal effects; the high-energy approximation; a simple quark-antiquark potential; and quark diagrams and the Zweig rule. (Auth.)
Quark Model Perspectives on Pentaquark Exotics
Maltman, Kim
2004-01-01
Expectations and predictions for pentaquark exotics based on the quark model perspective are presented. Recent quark model scenarios, and calculations performed in different realizations of the quark model approach, up to the end of March 2004, are also reviewed and discussed.
Top quark cross sections and differential distributions
Kidonakis, Nikolaos
2011-01-01
I present results for the top quark pair total cross section and the top quark transverse momentum distribution at Tevatron and LHC energies. I also present results for single top quark production. All calculations include NNLO corrections from NNLL threshold resummation.
Pole masses of quarks in dimensional reduction
International Nuclear Information System (INIS)
Pole masses of quarks in quantum chromodynamics are calculated to the two-loop order in the framework of the regularization by dimensional reduction. For the diagram with a light quark loop, the non-Euclidean asymptotic expansion is constructed with the external momentum on the mass shell of a heavy quark
Mesons in the Constituent Quark Model
Institute of Scientific and Technical Information of China (English)
WANG Li; PING Jia-Lun
2007-01-01
The quark-antiquark (q(-q)) spectrum is studied by solving the Schrǒdinger equation in the framework of non-relativistic constituent quark model. An overall good fit to the experimental data of meson is obtained. The interactions between quark and antiquark consist of quadratic colour confinement-exchange, one-gluon-exchange, and Goldstone-boson-exchange potentials.
The gauge technique for heavy quarks
Delbourgo, R.; Liu, D.
1996-01-01
It is possible to determine a propapagator for heavy quarks to order 1/m in any covariant gauge, which applies universally to all quarks, by using the gauge technique. The leading behaviour is given by a _0F_2 function and the result is reliable in the infrared limit, accounting for soft-gluon corrections to the quark in internal loops.
Lattice QCD thermodynamics with Wilson quarks
Ejiri, Shinji
2007-01-01
We review studies of QCD thermodynamics by lattice QCD simulations with dynamical Wilson quarks. After explaining the basic properties of QCD with Wilson quarks at finite temperature including the phase structure and the scaling properties around the chiral phase transition, we discuss the critical temperature, the equation of state and heavy-quark free energies.
Why quarks cannot be fundamental particles
Kalman, C. S.
2004-01-01
Many reasons why quarks should be considered composite particles are found in the book Preons by D'Souza and Kalman. One reason not found in the book is that all the quarks except for the u quark decay. The electron and the electron neutrino do not decay. A model of fundamental particles based upon the weak charge is presented.
Bound states of singlet quarks at LHC
Krasnikov, N. V.
1996-01-01
We discuss the discovery potential of the bound states of singlet quarks at LHC. We find that it is possible to discover bound states of singlet quarks at LHC with singlet quark masses up to 300 Gev for $e_{Q} = \\frac{2}{3}$ and up to 200 Gev for $e_{Q} = -\\frac{1}{3}$.
Greenlee, H B; Abolins, M; Acharya, B S; Adams, M; Adams, T; Agelou, M; Agram, J L; Ahn, S H; Ahsan, M; Alexeev, G D; Alkhazov, G; Alton, A; Alverson, G; Alves, G A; Anastasoaie, M; Andeen, T; Anderson, S; Andrieu, B; Arnoud, Y; Askew, A; Åsman, B; Assis-Jesus, A C S; Atramentov, O; Autermann, C; Avila, C; Badaud, F; Baden, A; Baldin, B Yu; Balm, P W; Banerjee, S; Barberis, E; Bargassa, P; Baringer, P; Barnes, C; Barreto, J; Bartlett, J F; Bassler, U; Bauer, D; Bean, A; Beauceron, S; Begel, M; Bellavance, A; Beri, S B; Bernardi, G; Bernhard, R; Bertram, I; Besançon, M; Beuselinck, R; Bezzubov, V A; Bhat, P C; Bhatnagar, V; Binder, M; Biscarat, C; Black, K M; Blackler, I; Blazey, G; Blekman, F; Blessing, S; Bloch, D; Blumenschein, U; Böhnlein, A; Boeriu, O; Bolton, T A; Borcherding, F; Borissov, G; Bos, K; Bose, T; Brandt, A; Brock, R; Brooijmans, G; Bross, A; Buchanan, N J; Buchholz, D; Bühler, M; Büscher, V; Burdin, S; Burnett, T H; Busato, E; Butler, J M; Bystrický, J; Caron, S; Carvalho, W; Casey, B C K; Cason, N M; Castilla-Valdez, H; Chakrabarti, S; Chakraborty, D; Chan, K M; Chandra, A; Chapin, D; Charles, F; Cheu, E; Cho, D K; Choi, S; Choudhary, B; Christiansen, T; Christofek, L; Claes, D; Clement, B; Clément, C; Coadou, Y; Cooke, M; Cooper, W E; Coppage, D; Corcoran, M; Cothenet, A; Cousinou, M C; Cox, B; Crepe-Renaudin, S; Cristetiu, M; Cutts, D; Da Motta, H; Davies, B; Davies, G; Davis, G A; De, K; de Jong, P; De Jong, S J; De La Cruz-Burelo, E; De Oliveira Martins, C; Dean, S; Degenhardt, J D; Déliot, F; Demarteau, M; Demina, R; Demine, P; Denisov, D; Denisov, S P; Desai, S; Diehl, H T; Diesburg, M; Doidge, M; Dong, H; Doulas, S; Dudko, L V; Duflot, L; Dugad, S R; Duperrin, A; Dyer, J; Dyshkant, A; Eads, M; Edmunds, D; Edwards, T; Ellison, J; Elmsheuser, J; Elvira, V D; Eno, S; Ermolov, P; Eroshin, O V; Estrada, J; Evans, D; Evans, H; Evdokimov, A; Evdokimov, V N; Fast, J; Fatakia, S N; Feligioni, L; Ferbel, T; Fiedler, F; Filthaut, F; Fisher, W; Fisk, H E; Fleck, I; Fortner, M; Fox, H; Fu, S; Fuess, S; Gadfort, T; Galea, C F; Gallas, E; Galyaev, E; García, C; García-Bellido, A; Gardner, J; Gavrilov, V; Gay, P; Gelé, D; Gelhaus, R; Genser, K; Gerber, C E; Gershtein, Yu; Ginther, G; Golling, T; Gómez, B; Gounder, K; Goussiou, A; Grannis, P D; Greder, S; Abazov, V M; Greenwood, Z D; Gregores, E M; Gris, P; Grivaz, J F; Groer, L; Grünendahl, S; Grünewald, M W; Gurzhev, S N; Gutíerrez, G; Gutíerrez, P; Haas, A; Hadley, N J; Hagopian, S; Hall, I; Hall, R E; Han, C; Han, L; Hanagaki, K; Harder, K; Harrington, R; Hauptman, J M; Hauser, R; Hays, J; Hebbeker, T; Hedin, D; Heinmiller, J M; Heinson, A P; Heintz, U; Hensel, C; Hesketh, G; Hildreth, M D; Hirosky, R; Hobbs, J D; Hoeneisen, B; Hohlfeld, M; Hong, S J; Hooper, R; Houben, P; Hu, Y; Huang, J; Iashvili, I; Illingworth, R; Ito, A S; Jabeen, S; Jaffré, M; Jain, S; Jain, V; Jakobs, K; Jenkins, A; Jesik, R; Johns, K; Johnson, M; Jonckheere, A; Jonsson, P; Juste, A; Käfer, D; Kahl, W; Kahn, S; Kajfasz, E; Kalinin, A M; Kalk, J; Karmanov, D; Kasper, J; Kau, D; Kaur, R; Kehoe, R; Kermiche, S; Kesisoglou, S; Khanov, A; Kharchilava, A I; Kharzheev, Yu M; Kim, H; Klima, B; Klute, M; Kohli, J M; Kopal, M; Korablev, V M; Kotcher, J; Kothari, B; Koubarovsky, A; Kozelov, A V; Kozminski, J; Kryemadhi, A; Krzywdzinski, S; Kuleshov, S; Kulik, Y; Kumar, A; Kunori, S; Kupco, A; Kurca, T; Kvita, J; Lager, S; Lahrichi, N; Landsberg, G L; Lazoflores, J; Le Bihan, A C; Lebrun, P; Lee, W M; Leflat, A; Lehner, F; Leonidopoulos, C; Lévêque, J; Lewis, P; Li, J; Li, Q Z; Lima, J G R; Lincoln, D; Linn, S L; Linnemann, J T; Lipaev, V V; Lipton, R; Lobo, L; Lobodenko, A; Lokajícek, M; Lounis, A; Love, P; Lubatti, H J; Lueking, L; Lynker, M; Lyon, A L; Maciel, A K A; Madaras, R J; Mättig, P; Magass, C; Magerkurth, A; Magnan, A M; Makovec, N; Mal, P K; Malbouisson, H B; Malik, S; Malyshev, V L; Mao, H S; Maravin, Y; Martens, M; Mattingly, S E K; Mayorov, A A; McCarthy, R; McCroskey, R; Meder, D; Melanson, H L; Melnitchouk, A S; Mendes, A; Merkin, M; Merritt, K W; Meyer, A; Michaut, M; Miettinen, H; Mitrevski, J; Mokhov, N V; Molina, J; Mondal, N K; Moore, R W; Muanza, G S; Mulders, M; Mutaf, Y D; Nagy, E; Narain, M; Naumann, N A; Neal, H A; Negret, J P; Nelson, S; Neustroev, P; Nöding, C; Nomerotski, A; Novaes, S F; Nunnemann, T; Nurse, E; O'Dell, V; O'Neil, D C; Oguri, V; Oliveira, N; Oshima, N; Oteroy-Garzon, G J; Padley, P; Parashar, N; Park, S K; Parsons, J; Partridge, R; Parua, N; Patwa, A; Perea, P M; Pérez, E; Petroff, P; Petteni, M; Phaf, L; Piegaia, R; Pleier, M A; Podesta-Lerma, P L M; Podstavkov, V M; Pogorelov, Y; Pope, B G; Prado da Silva, W L; Prosper, H B; Protopopescu, S D; Qian, J; Quadt, A; Quinn, B; Rani, K J; Ranjan, K; Rapidis, P A; Ratoff, P N; Reay, N W; Reucroft, S; Rijssenbeek, M; Ripp-Baudot, I; Rizatdinova, F K; Rodrigues, R F; Royon, C; Rubinov, P; Ruchti, R; Rud, V I; Sajot, G; Sánchez-Hernández, A; Sanders, M P; Santoro, A F S; Savage, G; Sawyer, L; Scanlon, T; Schaile, A D; Schamberger, R D; Schellman, H; Schieferdecker, P; Schmitt, C; Schwartzman, A; Schwienhorst, R; Sen-Gupta, S; Severini, H; Shabalina, E; Shamim, M; Shary, V; Shchukin, A A; Shephard, W D; Shivpuri, R K; Shpakov, D; Sidwell, R A; Simák, V; Sirotenko, V I; Skubic, P L; Slattery, P F; Smith, R P; Smolek, K; Snow, G R; Snow, J; Snyder, S; Söldner-Rembold, S; Song, X; Sonnenschein, L; Sopczak, A; Sosebee, M; Soustruznik, K; Souza, M; Spurlock, B; Stanton, N R; Stark, J; Steele, J; Stevenson, K; Stolin, V; Stone, A; Stoyanova, D A; Strandberg, J; Strang, M A; Strauss, M; Ströhmer, R; Strom, D; Strovink, M; Stutte, L; Sumowidagdo, S; Sznajder, A; Talby, M; Tamburello, P; Taylor, W; Telford, P; Temple, J; Thomas, E; Thooris, B; Tomoto, M; Toole, T; Torborg, J; Towers, S; Trefzger, T; Trincaz-Duvoid, S; Tuchming, B; Tully, C; Turcot, A S; Tuts, P M; Uvarov, L; Uvarov, S; Uzunyan, S; Vachon, B; Van Kooten, R; Van Leeuwen, W M; Varelas, N; Varnes, E W; Vartapetian, A H; Vasilyev, I A; Vaupel, M; Verdier, P; Vertogradov, L S; Verzocchi, M; Villeneuve-Séguier, F; Vlimant, J R; Von Törne, E; Vreeswijk, M; Vu-Anh, T; Wahl, H D; Walker, R; Wang, L; Wang, Z M; Warchol, J; Watts, G; Wayne, M; Weber, M; Weerts, H; Wegner, M; Wermes, N; White, A; White, V; Wicke, D; Wijngaarden, D A; Wilson, G W; Wimpenny, S J; Wittlin, J; Wobisch, M; Womersley, J; Wood, D R; Wyatt, T R; Xu, Q; Xuan, N; Yacoob, S Y; Yamada, R; Yan, M; Yasuda, T; Yatsunenko, Y A; Yen, Y; Yip, K; Yoo, H D; Youn, S W; Yu, J; Yurkewicz, A; Zabi, A; Zatserklyaniy, A; Zdrazil, M; Zeitnitz, C; Zhang, D; Zhang, X; Zhao, T; Zhao, Z; Zhou, B; Zhu, J; Zielinski, M; Zieminska, D; Zieminski, A; Zitoun, R; Zutshi, V; Zverev, E G
2005-01-01
In this talk I will present recent preliminary results from the D0 experiment from Tevatron Run II ($p\\bar p$ collisions at $\\sqrt{s} = 1.96$ TeV). The results presented in this talk include top quark pair production cross section, top quark mass, and upper limits on single top quark production.
Quark Masses and Renormalization Constants from Quark Propagator and 3-point Functions
Becirevic, D.; Lubicz, V.; Martinelli, G.; Testa, M.(INFN Laboratori Nazionali di Frascati, Frascati, Italy)
1999-01-01
We have computed the light and strange quark masses and the renormalization constants of the quark bilinear operators, by studying the large-p^2 behaviour of the lattice quark propagator and 3-point functions. The calculation is non-perturbatively improved, at O(a), in the chiral limit. The method used to compute the quark masses has never been applied so far, and it does not require an explicit determination of the quark mass renormalization constant.
Semileptonic Decays of Heavy Lambda Baryons in a Quark Model
Energy Technology Data Exchange (ETDEWEB)
Winston Roberts; Muslema Pervin; Simon Capstick
2005-03-01
The semileptonic decays of {Lambda}{sub c} and {Lambda}{sub b} are treated in the framework of a constituent quark model. Both nonrelativistic and semirelativistic Hamiltonians are used to obtain the baryon wave functions from a fit to the spectra, and the wave functions are expanded in both the harmonic oscillator and Sturmian bases. The latter basis leads to form factors in which the kinematic dependence on q{sup 2} is in the form of multipoles, and the resulting form factors fall faster as a function of q{sup 2} in the available kinematic ranges. As a result, decay rates obtained in the two models using the Sturmian basis are significantly smaller than those obtained using the harmonic oscillator basis. In the case of the {Lambda}{sub c}, decay rates calculated using the Sturmian basis are closer to the experimentally reported rates. However, we find a semileptonic branching fraction for the {Lambda}{sub c} to decay to excited {Lambda}* states of 11% to 19%, in contradiction with what is assumed in available experimental analyses. Our prediction for the {Lambda}{sub b} semileptonic decays is that decays to the ground state {Lambda}{sub c} provide a little less than 70% of the total semileptonic decay rate. For the decays {Lambda}{sub b} {yields} {Lambda}{sub c}, the analytic form factors we obtain satisfy the relations expected from heavy-quark effective theory at the non-recoil point, at leading and next-to-leading orders in the heavy-quark expansion. In addition, some features of the heavy-quark limit are shown to naturally persist as the mass of the heavy quark in the daughter baryon is decreased.
Search for the top quark and other new particles at D0
International Nuclear Information System (INIS)
Preliminary results from the search for the top quark and other new particles in p bar p collisions at √s = 1.8 TeV are reported. In a data sample corresponding to an integrated luminosity of about 7.5 pb-1, one candidate event for top quark is found in the di-lepton channel. A lower limit for the mass of the top quark of 103 GeV/c2 (99 Gev/c2) is obtained at 95% confidence level with (without) background subtraction. Status of searches for other new particles that may arise from new phenomena beyond the standard model is summarized
Connected contribution to the kernel of the evolution equation for 3-quark Wilson loop operator
Grabovsky, A. V.
2013-01-01
The connected contribution to the kernel of the evolution equation for the 3-quark Wilson loop operator was derived within Balitsky high energy operator expansion. Its C-odd part was linearized and transferred to the momentum space.
Electroproduction of light quark baryons
International Nuclear Information System (INIS)
The status of electromagnetic excitation of light quark (u, d) baryon states is reviewed and confronted with results of calculations within the framework of microscopic models of the baryon structure and the photon-baryon coupling. Prospects for a qualitative improvement of our knowledge in this sector using photon and electron beams at the new, intermediate energy continuous wave electron machines are discussed
Quark Matter '87: Concluding remarks
International Nuclear Information System (INIS)
This year marked the beginning of the experimental program at BNL and CERN to probe the properties of ultra dense hadronic matter and to search for the quark-gluon plasma phase of matter. Possible implications of the preliminary findings are discussed. Problems needing further theoretical and experimental study are pointed out. 50 refs
Energy Technology Data Exchange (ETDEWEB)
Barberis, Emanuela; /Northeastern U.
2006-05-01
A summary of the results on the measurement of the Top Quark mass and the study of the kinematics of the t{bar t} system at the Tevatron collider is presented here. Results from both the CDF and D0 collaborations are reported.
Young, Robert D.
1973-01-01
Discusses the charge independence, wavefunctions, magnetic moments, and high-energy scattering of hadrons on the basis of group theory and nonrelativistic quark model with mass spectrum calculated by first-order perturbation theory. The presentation is explainable to advanced undergraduate students. (CC)
Hydrodynamics of a quark droplet
DEFF Research Database (Denmark)
Bjerrum-Bohr, Johan J.; Mishustin, Igor N.; Døssing, Thomas
2012-01-01
We present a simple model of a multi-quark droplet evolution based on the hydrodynamical description. This model includes collective expansion of the droplet, effects of the vacuum pressure and surface tension. The hadron emission from the droplet is described following Weisskopf's statistical...
Are quarks and leptons composite
International Nuclear Information System (INIS)
This chapter examines composite quarks and leptons by starting with generalities and gradually concentrating on the specific example of the rishon model. Assumes that the standard model is a valid theory of quarks, leptons and their interactions. Discusses the various open problems which remain, even if the standard model is accepted. Reviews the pros and cons of the several possible solutions which exist for each of the open problems (e.g., grand unification, technicolor, horizontal symmetries, supersymmetry, composite quarks and leptons). Attempts to find a simple realistic model for composite quarks and leptons. Offers the following line of reasoning: 1) assume the standard model; 2) show a need to go beyond it; 3) consider different classes of ideas; 4) concentrate on the notion of compositeness; 5) study its general difficulties, mainly the scale problem; 6) assume a connection between composite massless fermions and an unbroken chiral symmetry; 7) establish a general framework based on hypercolor and a chiral symmetry; 8) establish the general requirements for a candidate model; 9) find the minimal scheme; and 10) study it and discover its successes and failures
2003-01-01
Fitted with new state-of-the-art silicon detectors, NA60 is prepared to study the phase transition from confined hadronic matter to a deconfined (free) quark-gluon plasma, a state of matter which probably existed an instant after the Big Bang.
Quark Orbital Angular Momentum from Lattice QCD
N. Mathur; Dong, S. J.; Liu, K. F.; Mankiewicz, L.; Mukhopadhyay, N. C.
1999-01-01
We calculate the quark orbital angular momentum of the nucleon from the quark energy-momentum tensor form factors on the lattice. The disconnected insertion is estimated stochastically which employs the $Z_2$ noise with an unbiased subtraction. This reduced the error by a factor of 4 with negligible overhead. The total quark contribution to the proton spin is found to be $0.30 \\pm 0.07$. From this and the quark spin content we deduce the quark orbital angular momentum to be $0.17 \\pm 0.06$ wh...
Top quark mass measurements in ATLAS
International Nuclear Information System (INIS)
The top quark is a fundamental constituent of the Standard Model (SM). The properties of this quark are accurately predicted by this theory, except for its mass, which remains a fundamental parameter of the SM. With the advent of the Large Hadron Collider (LHC), many million of top-antitop quark pairs are available for study. With such statistics, the physics of the top quark has entered the precision era. In this note, the most recent experimental results by ATLAS concerning the top quark mass are reported
Gapless Color-Flavor-Locked Quark Matter
DEFF Research Database (Denmark)
Alford, Mark; Kouvaris, Christoforos; Rajagopal, Krishna
2004-01-01
In neutral cold quark matter that is sufficiently dense that the strange quark mass M_s is unimportant, all nine quarks (three colors; three flavors) pair in a color-flavor locked (CFL) pattern, and all fermionic quasiparticles have a gap. We argue that as a function of decreasing quark chemical...... a linear combination Qtilde of electric and color charges, but it is a Qtilde-conductor with a nonzero electron density. These electrons and the gapless quark quasiparticles make the low energy effective theory of the gapless CFL phase and, consequently, its astrophysical properties are qualitatively...
Top quark physics with the CMS experiment
Directory of Open Access Journals (Sweden)
Cuevas Javier
2014-04-01
Full Text Available An overview of recent top quark measurements in proton-proton collisions at √s = 7 and 8 TeV in data collected with the CMS experiment at the LHC, using a data sample collected during the years 2011 and 2012 is presented. Measurements of top quark pair production cross sections in several top quark final states are reported, as well as electroweak production of single top quarks in both t-and tW-channels. The mass of the top quark is estimated by different methods.
Searches for Scalar Top and Scalar Bottom Quarks at LEP2
Antonelli, M; Pepé-Altarelli, M; Orejudos, W; Zachariadou, K
1997-01-01
Searches for scalar top and bottom quarks have been performed with data collected by the ALEPH detector at LEP. The data sample consists of 21.7 pb^-1 taken at sqrt{s} = 161, 170, and 172~GeV and 5.7 pb^-1 taken at sqrt{s} = 130 and 136~GeV. No evidence for scalar top quarks or scalar bottom quarks was found in the channels stop --> c chi, stop --> b l snu, and sbottom --> b chi. For the channel stop --> c chi a limit of 67 GeV/c^2 has been set on the scalar top quark mass, independent of the mixing angle between the supersymmetric partners of the left and right-handed states of the top quark. This limit assumes a mass difference between the stop and the chi of at least 10 GeV/c^2. For the channel stop --> b l snu the mixing-angle independent scalar top limit is 70 GeV/c^2, assuming a mass difference between the stop and the snu of at least 10 GeV/c^2. For the channel sbottom --> b chi, a limit of 73 GeV/c^2 has been set on the mass of the supersymmetric partner of the left-handed state of the bottom quark. T...
State of matter for quark stars
Lai, X Y
2009-01-01
It depends on the state of matter at supra-nuclear density to model pulsar's structure, which is unfortunately not certain due to the difficulties in physics. In cold quark matter at realistic baryon densities of compact stars (with an average value of $\\sim 2-3\\rho_0$), the interaction between quarks is so strong that they would condensate in position space to form quark-clusters. We argue that quarks in quark stars are grouped in clusters, then we apply two phenomenological models for quark stars, the polytropic model and Lennard-Jones model. Both of the two models have stiffer EoS, and larger maximum mass for quark stars (larger than 2 $M_\\odot$). The gravitational energy releases during the AIQ process could explain the observed energy of three supergiant flares from soft gamma-ray repeaters ($\\sim 10^{47}$ ergs).
Synthesis of baryons from unconfined quarks
International Nuclear Information System (INIS)
The cosmic temperature at which primordial quarks condense into baryons is calculated for a number of cases within a field theory of partially confined quarks that enjoys temporary asymptotic freedom. It is assumed that the mass of a quark in a dense quark anti-quark medium is a monotonic function of the medium, that is, that the so-called Archimedes effect is valid. It is shown that, within such models, unbound quark lifetimes are larger than the age of the universe at the time of the transition and that the Archimedes effect implies that the change of the medium from free to bound quarks is a phase transition. 1 figure, 1 table
How could quark polarization be measured
Efremov, A V
2000-01-01
The perspectives of two new nonstandard methods of transversal quark polarization measurement are considered: the jet handedness and the so-called "Collins effect" due to a spin dependent T-odd fragmentation function responsible for the left-right asymmetry in fragmenting of transversally polarized quarks. Recent experimental indications in favor of these effects are observed: 1. The correlation of the T-odd one-particle fragmentation functions found by DELPHI in Z to 2-jet decay. Integrated over the fraction of longitudinal and transversal momenta, this correlation is of 1.6% order, which means order of 13% for the analyzing power. 2. A rather large ( approximately=10%) handedness transversal to the production plane observed in the diffractive production of ( pi /sup -/ pi /sup +/ pi /sup -/) triples from nuclei by the 40 GeV/c pi /sup -/-beam. It shows a clear dynamic origin and resembles the single spin asymmetry behavior. All this makes us hope to use these effects in polarized DIS experiments for transve...
Energy change of a heavy quark in a viscous quark-gluon plasma with fluctuations
Jiang, Bing-feng; Hou, De-fu; Li, Jia-rong
2016-09-01
When a heavy quark travels through the quark-gluon plasma, the polarization and fluctuating chromoelectric fields will be produced simultaneously in the plasma. The drag force due to those fields exerting in return on the moving heavy quark will cause energy change to it. Based on the dielectric functions derived from the viscous chromohydrodynamics, we have studied the collisional energy change of a heavy quark traversing the viscous quark-gluon plasma including fluctuations of chromoelectric field. Numerical results indicate that the chromoelectric field fluctuations lead to an energy gain of the moving heavy quark. Shear viscosity suppresses the fluctuation-induced energy gain and the viscous suppression effect for the charm quark is much more remarkable than that for the bottom quark. While, the fluctuation energy gain is much smaller than the polarization energy loss in magnitude and the net energy change for the heavy quark is at loss.
The effect of dynamical quark mass on the calculation of a strange quark star's structure
Institute of Scientific and Technical Information of China (English)
Gholam Hossein Bordbar; Babak Ziaei
2012-01-01
We discuss the dynamical behavior of strange quark matter components,in particular the effects of density dependent quark mass on the equation of state of strange quark matter.The dynamical masses of quarks are computed within the Nambu-Jona-Lasinio model,then we perform strange quark matter calculations employing the MIT bag model with these dynamical masses.For the sake of comparing dynamical mass interaction with QCD quark-quark interaction,we consider the one-gluon-exchange term as the effective interaction between quarks for the MIT bag model.Our dynamical approach illustrates an improvement in the obtained equation of state values.We also investigate the structure of the strange quark star using TolmanOppenheimer-Volkoff equations for all applied models.Our results show that dynamical mass interaction leads to lower values for gravitational mass.
Inclusive Single-Spin Asymmetries, Quark-Photon, and Quark-Quark Correlations
Burkardt, Matthias
2016-01-01
We consider quark-photon correlations that have been proposed as a source for single-spin asymmetries in inclusive deep-inelastic scattering. A new sum rule for these correlators is derived and its phenomenological consequences are discussed. The results are interpreted within the context of an intuitive 'electrodynamic lensing' picture.
Why the proton spin is not due to quarks
International Nuclear Information System (INIS)
Recent EMC data on the spin-dependent proton structure function suggest that very little of the proton spin is due to the helicity of the quarks inside it. We argue that, at leading order in the 1/N/sub c/ expansion, none of the proton spin would be carried by quarks in the chiral limit where m/sub q/ = 0. This model-independent result is based on a physical picture of the nucleon as a soliton solution of the effective chiral Lagrangian of large-N/sub c/ QCD. The Skyrme model is then used to estimate quark contribution to the proton spin when chiral symmetry and flavor SU(3) are broken: this contribution turns out to be small, as suggested by the EMC. Next, we discuss the other possible contributions to the proton helicity in the infinite-momentum frame---polarized gluons (ΔG), and orbital angular momentum (L/sub z/). We argue on general grounds and by explicit example the ΔG = 0 and that if the parameters of the chiral Lagrangian are adjusted so that gluons carry /approximately/50% of the proton momentum, most of the orbital angular momentum L/sub z/ is carried by quarks. We mention several experiments to test the EMC results and their interpretation. 43 refs., 3 figs
S{sub 3} discrete group as a source of the quark mass and mixing pattern in 331 models
Energy Technology Data Exchange (ETDEWEB)
Cárcamo Hernández, A. E., E-mail: antonio.carcamo@usm.cl [Universidad Técnica Federico Santa María and Centro Científico-Tecnológico de Valparaíso, Casilla 110-V, Valparaíso (Chile); Martinez, R., E-mail: remartinezm@unal.edu.co; Nisperuza, Jorge [Departamento de Física, Universidad Nacional de Colombia, Ciudad Universitaria, Bogotá D.C. (Colombia)
2015-02-17
We propose a model based on the SU(3){sub C}⊗SU(3){sub L}⊗U(1){sub X} gauge symmetry with an extra S{sub 3}⊗Z{sub 2}⊗Z{sub 4}⊗Z{sub 12} discrete group, which successfully accounts for the SM quark mass and mixing pattern. The observed hierarchy of the SM quark masses and quark mixing matrix elements arises from the Z{sub 4} and Z{sub 12} symmetries, which are broken at a very high scale by the SU(3){sub L} scalar singlets (σ,ζ) and τ, charged under these symmetries, respectively. The Cabbibo mixing arises from the down-type quark sector whereas the up quark sector generates the remaining quark mixing angles. The obtained magnitudes of the CKM matrix elements, the CP violating phase, and the Jarlskog invariant are in agreement with the experimental data.
S{sub 3} discrete group as a source of the quark mass and mixing pattern in 331 models
Energy Technology Data Exchange (ETDEWEB)
Carcamo Hernandez, A.E. [Universidad Tecnica Federico Santa Maria and Centro Cientifico-Tecnologico de Valparaiso, Valparaiso (Chile); Martinez, R.; Nisperuza, Jorge [Universidad Nacional de Colombia, Ciudad Universitaria, Departamento de Fisica, Bogota D.C. (Colombia)
2015-02-01
We propose a model based on the SU(3){sub C} x SU(3){sub L} x U(1){sub X} gauge symmetry with an extra S{sub 3} x Z{sub 2} x Z{sub 4} x Z{sub 12} discrete group, which successfully accounts for the SM quark mass and mixing pattern. The observed hierarchy of the SM quark masses and quark mixing matrix elements arises from the Z{sub 4} and Z{sub 12} symmetries, which are broken at a very high scale by the SU(3){sub L} scalar singlets (σ,ζ) and τ, charged under these symmetries, respectively. The Cabbibo mixing arises from the down-type quark sector whereas the up quark sector generates the remaining quark mixing angles. The obtained magnitudes of the CKM matrix elements, the CP violating phase, and the Jarlskog invariant are in agreement with the experimental data. (orig.)
Heavy and light quarks in the instanton vacuum
Musakhanov M.
2011-01-01
Assuming the gluon field is well approximated by instanton configurations we derive a light quarks determinant and calculate its contribution to the specific heavy quarks correlators – namely, the heavy quark propagator and heavy quark-aniquark correlator, receiving the instanton generated light-heavy quarks interaction terms contributions. With these knowledge we calculate the light quark contribution to the interaction between heavy quarks, which might be essential for the properties of a f...
Quark mass and mixing in the 3-3-1 model with neutral leptons based on $D_4$ flavor symmetr
Vien, V V
2014-01-01
The $D_4$ flavor model based on $\\mathrm{SU}(3)_C \\otimes \\mathrm{SU}(3)_L \\otimes \\mathrm{U}(1)_X$ gauge symmetry is updated in which the quark mixing matrix is concentrated. After spontaneous breaking of flavor symmetry, with the constraint on Higgs VEVs in the Yukawa couplings, all of quarks have consistent masses and a small deviation from the unity is obtained at the tree-level. To obtain the quark mixing matrix consistent with experimental data in 2012, the violation terms with $\\underline{1}'$ under $D_4$ are introduced. The realistic quark mass and mixing are derived.
Top quark production near threshold and the top quark mass
Beneke, Martin; Smirnov, V A
1999-01-01
We consider top-anti-top production near threshold in $e^+ e^-$ collisions, resumming Coulomb-enhanced corrections at next-to-next-to-leading order (NNLO). We also sum potentially large logarithms of the small top quark velocity at the next-to-leading logarithmic level using the renormalization group. The NNLO correction to the cross section is large, and it leads to a significant modification of the peak position and normalization. We demonstrate that an accurate top quark mass determination is feasible if one abandons the conventional pole mass scheme and if one uses a subtracted potential and the corresponding mass definition. Significant uncertainties in the normalization of the $t\\bar{t}$ cross section, however, remain.
charmed baryon strong decays in a chiral quark model
Zhong, Xian-Hui
2007-01-01
Charmed baryon strong decays are studied in a chiral quark model. The data for the decays of $\\Lambda^+_c(2593)$, $\\Lambda^+_c(2625)$, $\\Sigma^{++,+,0}_c$ and $\\Sigma^{+,0}_c(2520)$, are accounted for successfully, which allows to fix the pseudoscalar-meson-quark couplings in an effective chiral Lagrangian. Extending this framework to analyze the strong decays of the newly observed charmed baryons, we classify that both $\\Lambda_c(2880)$ and $\\Lambda_c(2940)$ are $D$-wave states in the N=2 shell; $\\Lambda_c(2880)$ could be $|\\Lambda_c ^2 D_{\\lambda\\lambda}{3/2}^+>$ and $\\Lambda_c(2940)$ could be $|\\Lambda_c ^2 D_{\\lambda\\lambda}{5/2}^+>$. Our calculation also suggests that $\\Lambda_c(2765)$ is very likely a $\\rho$-mode $P$-wave excited state in the N=1 shell, and favors a $|\\Lambda_c ^4P_\\rho 1/2^->$ configuration. The $\\Sigma_c(2800)$ favors being a $|\\Sigma_c ^2P_\\lambda{1/2}^->$ state. But its being $|\\Sigma^{++}_c ^4 P_\\lambda{5/2}^->$ cannot be ruled out.
T-odd quark-gluon-quark correlation function in the diquark model
Lu, Zhun
2012-01-01
We study the transverse momentum dependent quark-gluon-quark correlation function. Using a spectator diquark model, we calculate the eight time-reversal-odd interaction-dependent twist-3 quark distributions appearing in the decomposition of the transverse momentum dependent quark-gluon-quark correlator. In order to obtain finite results, we assume a dipole form factor for the nucleon-quark-diquark coupling, instead of a point-like coupling. The results are compared with the time-reversal-odd interaction-independent twist-3 TMDs calculated in the same model.
Djukanovic, Dalibor
2016-01-01
We present a Mathematica package for the calculation of Wick contractions in quantum field theories - QCT. Furthermore the package aims at automatically generating code for the calculation of physical matrix elements, suitable for numerical evaluation in a C++ program. To that end commonly used algebraic manipulations for the calculation of matrix elements in lattice QCD are implemented.
Semileptonic Decays of Heavy Omega Baryons in a Quark Model
Energy Technology Data Exchange (ETDEWEB)
Muslema Pervin; Winston Roberts; Simon Capstick
2006-03-24
The semileptonic decays of {Omega}{sub c} and {Omega}{sub b} are treated in the framework of a constituent quark model developed in a previous paper on the semileptonic decays of heavy {Lambda} baryons. Analytic results for the form factors for the decays to ground states and a number of excited states are evaluated. For {Omega}{sub b} to {Omega}{sub c} the form factors obtained are shown to satisfy the relations predicted at leading order in the heavy-quark effective theory at the non-recoil point. A modified fit of nonrelativistic and semirelativistic Hamiltonians generates configuration-mixed baryon wave functions from the known masses and the measured {Lambda}{sub c}{sup +} {yields} {Lambda}e{sup +}{nu} rate, with wave functions expanded in both harmonic oscillator and Sturmian bases. Decay rates of {Omega}{sub b} to pairs of ground and excited {Omega}{sub c} states related by heavy-quark symmetry calculated using these configuration-mixed wave functions are in the ratios expected from heavy-quark effective theory, to a good approximation. Our predictions for the semileptonic elastic branching fraction of {Omega}{sub Q} vary minimally within the models we use. We obtain an average value of (84 {+-} 2%) for the fraction of {Omega}{sub c} {yields} {Xi}{sup (*)} decays to ground states, and 91% for the fraction of {Omega}{sub c} {yields} {Omega}{sup (*)} decays to the ground state {Omega}. The elastic fraction of {Omega}{sub b} {yields} {Omega}{sub c} ranges from about 50% calculated with the two harmonic-oscillator models, to about 67% calculated with the two Sturmian models.
Discovery of single top quark production
Gillberg, Dag
2011-01-01
The top quark is by far the heaviest known fundamental particle with a mass nearing that of a gold atom. Because of this strikingly high mass, the top quark has several unique properties and might play an important role in electroweak symmetry breaking—the mechanism that gives all elementary particles mass. Creating top quarks requires access to very high energy collisions, and at present only the Tevatron collider at Fermilab is capable of reaching these energies. Until now, top quarks have only been observed produced in pairs via the strong interaction. At hadron colliders, it should also be possible to produce single top quarks via the electroweak interaction. Studies of single top quark production provide opportunities to measure the top quark spin, how top quarks mix with other quarks, and to look for new physics beyond the standard model. Because of these interesting properties, scientists have been looking for single top quarks for more than 15 years. This thesis presents the first discovery of singl...
The quark structure of the nucleons
International Nuclear Information System (INIS)
The suitableness of the non-relativistic potential model for the description of quarks in nucleons is proved and the model extensively presented. Practical applications are some contributions to the nucleon-nucleon interaction which result from the quark structure of the nucleons. These are especially the quark-gluon exchange and the quark-pion exchange between nucleons. The influences of these interactions on the s and p scattering of the nucleons are calculated in the framework of the resonating-group method. Furthermore we study the change of the quark structure if two nucleons approach very closely. The interaction of the nucleons by quark-gluon exchange causes an increase of the nucleon radius and a shift of the quark momenta to lower values. On this base the momentum distribution of quarks in nuclei is calculated and a natural explanation of the EMC effect is given. The distance distribution of nucleons and their Fermi motion are calculated for this in the shell model. Then we make further considerations in connection with the flavor symmetry, the collapse of the nucleons and the properties of six-quark bags. Altogether it is shown that in the potential model the most different effects of the quark structure of nucleons can be surprisingly well described in an illustrative way. (orig.)
Hidden-Beauty Charged Tetraquarks and Heavy Quark Spin Conservation
Ali, A; Polosa, A D; Riquer, V
2014-01-01
Assuming the dominance of the spin-spin interaction in a diquark, we point out that the mass differences in the beauty sector M(Z_b') - M(Z_b) scale with quark masses as expected in QCD, with respect to the corresponding mass difference M(Z_c') - M(Z_c). Notably, we show that the decays Upsilon(10890) --> (h_b(1P), h_b(2P)) pi pi are compatible with heavy-quark spin conservation once the contributions of Z_b,Z_b' intermediate states are taken into account, Upsilon(10890) being either a Upsilon(5S) or the beauty analog of Y_c(4260).
The Instanton-Dyon Liquid Model V: Twisted Light Quarks
Liu, Yizhuang; Zahed, Ismail
2016-01-01
We discuss an extension of the instanton-dyon liquid model that includes twisted light quarks in the fundamental representation with explicit $Z_{N_c}$ symmetry for the case with equal number of colors $N_c$ and flavors $N_f$. We map the model on a 3-dimensional quantum effective theory, and analyze it in the mean-field approximation. The effective potential and the vacuum chiral condensates are made explicit for $N_f=N_c=2, 3$. The low temperature phase is center symmetric but breaks spontaneously flavor symmetry with $N_f-1$ massless pions. The high temperature phase breaks center symmetry but supports finite and unequal quark condensates.
Color superconductivity in quark matter
International Nuclear Information System (INIS)
We have studied color superconductivity (CSC) in high density quark matter with two flavors on the basis of a model hamiltonian with Debye-screened gluon propagator. We found that the most attractive quark interaction of this hamiltonian is in the JP = 0+ - 0- channel with color anti-symmetric and flavor anti-symmetric representation. We also found that there is an attraction in the JP = 1+ - 1- channel although the strength is somewhat weaker. Depending on the strength of αs, the magnitude of the gap can be as large as 50-100 MeV. Even at extremely high baryon density ρB ∼ 20ρ0, the gap still exists with the size of 10-20 MeV. Open problems related to the physics of CSC are also discussed. (author)
Rare supersymmetric top quark decays
International Nuclear Information System (INIS)
Two supersymmetric decays of the top quark, t → H+b and t → u1χ0, are discussed within the framework of the Minimal Supersymmetric Standard Model with radiatively induced breaking of SU(2) x U(1). The present possibility of detecting these decays, given the available bounds on supersymmetric parameters, is compared with the situation a Next e+e- Linear Collider would face if supersymmetric particles were still undiscovered after LEP II. The indirect implications for t → H+b and t → u1χ0 of a possible detection of the bottom quark decay b → sγ at the Standard Model level are taken into account. (orig.)
Quark Confinement and Force Unification
Directory of Open Access Journals (Sweden)
Stone R. A. Jr.
2010-04-01
Full Text Available String theory had to adopt a bi-scale approach in order to produce the weakness of gravity. Taking a bi-scale approach to particle physics along with a spin connection produces 1 the measured proton radius, 2 a resolution of the multiplicity of measured weak angle values 3 a correct theoretical value for the Z 0 4 a reason that h is a constant and 5 a “neutral current” source. The source of the “neutral current” provides 6 an alternate solution to quark confinement, 7 produces an effective r like potential, and 8 gives a reason for the observed but unexplained Regge trajectory like J M 2 behavior seen in quark composite particle spin families.
Quark Confinement and Force Unification
Directory of Open Access Journals (Sweden)
Stone R. A. Jr.
2010-04-01
Full Text Available String theory had to adopt a bi-scale approach in order to produce the weakness of gravity. Taking a bi-scale approach to particle physics along with a spin connection produces 1 the measured proton radius, 2 a resolution of the multiplicity of measured weak angle values 3 a correct theoretical value for the $Z^0$ 4 a reason that $h$ is a constant and 5 a "neutral current" source. The source of the "neutral current" provides 6 an alternate solution to quark confinement, 7 produces an effective r like potential, and 8 gives a reason for the observed but unexplained Regge trajectory like $J sim M^2$ behavior seen in quark composite particle spin families.
Semileptonic decays of $\\Lambda_b$ baryons in the relativistic quark model
Faustov, R N
2016-01-01
Semileptonic $\\Lambda_b$ decays are investigated in the framework of the relativistic quark model based on the quasipotential approach and the quark-diquark picture of baryons. The decay form factors are expressed through the overlap integrals of the initial and final baryon wave functions. All calculations are done without employing nonrelativistic and heavy quark expansions. The momentum transfer dependence of the decay form factors is explicitly determined in the whole accessible kinematical range without any extrapolations or model assumptions. Both the heavy-to-heavy $\\Lambda_b\\to\\Lambda_c\\ell\
Walsh, Karen McNulty
2011-03-28
Near-light-speed collisions of gold ions provide a recipe for in-depth explorations of matter and fundamental forces. The Relativistic Heavy Ion Collider (RHIC) has produced the most massive antimatter nucleus ever discovered—and the first containing an anti-strange quark. The presence of strange antimatter makes this antinucleus the first to be entered below the plane of the classic Periodic Table of Elements, marking a new frontier in physics.
Nontopological Soliton in the Polyakov Quark Meson Model
Jin, Jinshuang
2016-01-01
In mean field approximation, we study a nontopological soliton of Polyakov Quark Meson Model in the presence of fermionic vacuum term with two flavors at finite temperature and density. The behavior of the effective potential evolving with temperature supports the existence of the stable soliton solution as long as $T\\leq T_{\\chi}^c$ for both crossover and first-order phase transition, and these solutions are calculated with some appropriate boundary conditions. However, it is found that only if $T\\leq T^c_d$, the energy of the soliton $M_N$ is less than the energy of three free constituent quarks $3M_q$. As $T> T^c_d$, there is a instant delocalization phase transition from hadron matter to quark matter. The phase diagram together with the location of critical end point (CEP) has been obtained in $T$ and $\\mu$ plane. We notice that two critical temperatures always satisfy $T^c_d\\leq T_{\\chi}^c$. In the end, we present and compare the result for temperature variation of thermodynamic pressure at zero chemical...
Bashinsky, S V
1996-01-01
We reduce the problem of many-channel hadron scattering at nonrelativistic energies to calculations on the scale of a few fermis. Having thus disentangled kinematics from interior quark dynamics, we study their interplay when a quark state occurs near a hadronic threshold. Characteristic parameters, such as the observed peak width, the decay width, and the shape of a cross-section itself are highly affected by the threshold. A general pole-form expression for the S-matrix in an arbitrary background is given, and the pole structure of S is examined. We show that at a hadronic threshold two poles in S are generally important. We also classify the S-matrix pole structure considering an example where nonsingular coupled channels are closed at the threshold. The framework of our paper is the P-matrix formalism, which is reviewed and extended for use together with conventional methods of computing quark-gluon dynamics. Results and applications are illustrated for the doubly strange two-baryon system, the detailed a...
Probing nucleons with photons at the quark level
Eichmann, Gernot
2014-01-01
The description of electromagnetic interactions with hadrons from the quark level requires knowledge of the underlying quark-gluon ingredients. I discuss some properties of the quark-photon vertex and quark Compton vertex, along with the role of electromagnetic gauge invariance and vector-meson dominance. A simple parametrization for the quark-photon vertex is given.
Effect of a Small Current Quark Mass on Bag Constant
Institute of Scientific and Technical Information of China (English)
ZONGHong-Shi; FENGHong-Tao; SUNWei-Min; DINGXiao-Ping; PINGJia-Lun
2004-01-01
A method for obtaining the small current quark mass effect on the dressed quark propagator within the Dyson Schwinger approach is developed. From this the small current quark mass dependence of the bag constant is evaluated. It is found that the bag constant decreases with the increasing current quark mass and the contribution of the current quark mass cannot be dropped.
Effect of a Small Current Quark Mass on Bag Constant
Institute of Scientific and Technical Information of China (English)
ZONG Hong-Shi; FENG Hong-Tao; SUN Wei-Min; DING Xiao-Ping; PING Jia-Lun
2004-01-01
A method for obtaining the small current quark mass effect on the dressed quark propagator within the Dyson-Schwinger approach is developed. From this the small current quark mass dependence of the bag constant is evaluated. It is found that the bag constant decreases with the increasing current quark mass and the contribution of the current quark mass cannot be dropped.
A precise measurement of the top quark mass
Energy Technology Data Exchange (ETDEWEB)
Mohr, Brian N.; /UCLA
2007-04-01
We present a measurement of the mass of the top quark using data from proton-antiproton collisions recorded at the CDF experiment in Run II of the Fermilab Tevatron. Events are selected from the single lepton plus jets final state (t{bar t} {yields} W{sup +}bW{sup -}{bar b} {yields} {ell}{nu}bq{bar q}{prime}{bar b}). The top quark mass is extracted using a calculation of the probability density for a t{bar t} final state to resemble a data event. This probability density is a function of both top quark mass and energy scale of calorimeter jets, constrained in situ with the hadronic W boson mass. Using 167 events observed in 955 pb{sup -1} integrated luminosity, we achieve the single most precise measurement of top quark mass to date of 170.8 {+-} 2.2 (stat.) {+-} 1.4 (syst.) GeV/c{sup 2}, where the quoted statistical uncertainty includes uncertainty from the determination of the jet energy scale.
Precision Top-Quark Mass Measurements at CDF
Energy Technology Data Exchange (ETDEWEB)
Aaltonen, T.; /Helsinki Inst. of Phys.; Alvarez Gonzalez, B.; /Oviedo U. /Cantabria Inst. of Phys.; Amerio, S.; /INFN, Padua; Amidei, D.; /Michigan U.; Anastassov, A.; /Northwestern U. /Fermilab; Annovi, A.; /Frascati; Antos, J.; /Comenius U.; Apollinari, G.; /Fermilab; Appel, J.A.; /Fermilab; Arisawa, T.; /Waseda U.; Artikov, A.; /Dubna, JINR /Texas A-M
2012-07-01
We present a precision measurement of the top-quark mass using the full sample of Tevatron {radical}s = 1.96 TeV proton-antiproton collisions collected by the CDF II detector, corresponding to an integrated luminosity of 8.7 fb{sup -1}. Using a sample of t{bar t} candidate events decaying into the lepton+jets channel, we obtain distributions of the top-quark masses and the invariant mass of two jets from the W boson decays from data. We then compare these distributions to templates derived from signal and background samples to extract the top-quark mass and the energy scale of the calorimeter jets with in situ calibration. The likelihood fit of the templates from signal and background events to the data yields the single most-precise measurement of the top-quark mass, mtop = 172.85 {+-} 0.71 (stat) {+-} 0.85 (syst) GeV/c{sup 2}.
A top quark mass measurement using a matrix element method
Energy Technology Data Exchange (ETDEWEB)
Linacre, Jacob Thomas; /Oxford U.
2010-02-01
A measurement of the mass of the top quark is presented, using top-antitop pair (t{bar t}) candidate events for the lepton+jets decay channel. The measurement makes use of Tevatron p{bar p} collision data at centre-of-mass energy {radical}s = 1.96 TeV, collected at the CDF detector. The top quark mass is measured by employing an unbinned maximum likelihood method where the event probability density functions are calculated using signal (t{bar t}) and background (W+jets) matrix elements, as well as a set of parameterised jet-to-parton mapping functions. The likelihood function is maximised with respect to the top quark mass, the fraction of signal events, and a correction to the jet energy scale (JES) of the calorimeter jets. The simultaneous measurement of the JES correction ({Delta}{sub JES}) provides an in situ jet energy calibration based on the known mass of the hadronically decaying W boson. Using 578 lepton+jets candidate events corresponding to 3.2 fb{sup -1} of integrated luminosity, the top quark mass is measured to be m{sub t} = 172.4 {+-} 1.4 (stat+{Delta}{sub JES}) {+-} 1.3 (syst) GeV=c{sup 2}, one of the most precise single measurements to date.
Gluon condensate, quark propagation, and dilepton production in the quark-gluon plasma
Mustafa, M. G.; Sch"afer, A.; Thoma, M. H.
1999-01-01
A calculation of the thermal quark propagator is presented taking the gluon condensate above the critical temperature into account. The quark dispersion relation and the dilepton production following from this propagator are derived.
Quark Propagation in a Quark-Gluon Plasma with Gluon Condensate
Schaefer, Andreas; Thoma, Markus H.
1998-01-01
We present a calculation of the thermal quark propagator taking the gluon condensate above the critical temperature into account. The quark dispersion relation following from this propagator, describing two massive modes, is discussed.
Vector Susceptibility of QCD Vacuum from an Effective Quark-Quark Interaction
Institute of Scientific and Technical Information of China (English)
ZONG Hong-Shi; QI Shi; CHEN Wei; WU Xiao-Hua
2003-01-01
.A new approach for calculating vacuum susceptibilities from an effective quark-quark interaction model is derived. As a special case, the vector vacuum susceptibility is calculated. A comparison with the results of the previous approaches is given.
Effect of a Small Current Quark Mass on Dressed Gluon and Quark Propagator
Institute of Scientific and Technical Information of China (English)
HOU Feng-Yao; GU Jian-Zhong; ZONG Hong-Shi; L(U)Xiao-Fu
2004-01-01
Based on the Dyson-Schwinger approach, a method for obtaining the small current quark mass effect on the dressed gluon and quark propagator is developed. A comparison with the results of the previous approach is given.
Vector Susceptibility of QCD Vacuum from an Effective Quark-Quark Interaction
Institute of Scientific and Technical Information of China (English)
ZONGHong-Shi; QIShi; CHENWei; WUXiao-Hua
2003-01-01
A new approach for calculating vacuum susceptibilities from an effective quark-quark interaction model is derived. As a special case, the vector vacuum susceptibility is calculated. A comparison with the results of the previous approaches is given.
Lattice Landau gauge quark propagator and the quark-gluon vertex
Oliveira, Orlando; Silva, Paulo J; Skullerud, Jon-Ivar; Sternbeck, Andre; Williams, Anthony G
2016-01-01
We report preliminary results of our ongoing lattice computation of the Landau gauge quark propagator and the soft gluon limit of the quark-gluon vertex with 2 flavors of dynamical O(a) improved Wilson fermions.
Quark matter in massive neutron stars
International Nuclear Information System (INIS)
The recent observation of the pulsar PSR J1614-2230 with a mass of 1.97 solar masses gives a strong constraint on the nuclear matter equation of state. We explore the parameter ranges for a parameterized equation of state for quark stars. We find that such massive objects made of absolutely stable strange quark matter can reach the new constraint only if effects from the strong coupling constant and color superconductivity are considered. Also hybrid stars are able to be massive but a pure quark matter core appears only if the hadronic equation of state is stiff. A soft hadronic equation of state would imply that hybrid stars contain just a core of quark hadron mixed phase. In general, due to the softening of the equation of state at the quark-hadron phase transition the masses of hybrid stars stay below the ones of hadronic and pure quark stars.
Experimental Studies of Top Quark Production
Wagner-Kuhr, Jeannine
2016-01-01
In this review article three promising aspects of top quark production are discussed: the charge asymmetry in top quark pair production, the search for resonant top quark pair production, and electroweak single top quark production. First, an overview of the theoretical predictions of top quark pair and single top quark production is given. Then, for each topic the general analysis strategy and improvements are exemplarily explained using selected analyses and are put into the context of the global status at the beginning of LHC Run II and progress in this field. The example analyses discussed in more detail in this article use data from the LHC experiment CMS and for the charge asymmetry studies also data from the Tevatron experiment CDF have been used.
Single top quark production with CMS
Mitra, Soureek
2016-01-01
Measurements of single top quark production are presented, performed using CMS data collected in 2011, 2012 and 2015 at centre-of-mass energies of 7, 8 and 13 TeV respectively. The cross sections for the electroweak production of single top quarks in the t-channel and in association with W-bosons is measured and the results are used to place constraints on the CKM matrix element Vtb. In the t-channel the ratio of top and anti-top production cross sections is determined and compared with predictions from different parton density distribution functions. In the same channel, the inclusive cross-section in the fiducial volume is also measured. Measurements of top quark properties in single top quark production such as the top-quark polarisation, W-helicity in top quark decay and searches for anomalous couplings to gluons, photons are also presented,. A search for the s-channel is also performed.
Physics of the nucleon sea quark distributions
Energy Technology Data Exchange (ETDEWEB)
Vogt, R.
2000-03-10
Sea quark distributions in the nucleon have naively been expected to be generated perturbatively by gluon splitting. In this case, there is no reason for the light quark and anti-quark sea distributions to be different. No asymmetries in the strange or heavy quark sea distributions are predicted in the improved parton model. However,recent experiments have called these naive expectations into question. A violation of the Gottfried sum rule has been measured in several experiments, suggesting that (bar u) < (bar d) in the proton. Additionally, other measurements, while not definitive, show that there may be an asymmetry in the strange and anti-strange quark sea distributions. These effects may require nonperturbative explanations. In this review we first discuss the perturbative aspects of the sea quark distributions. We then describe the experiments that could point to nonperturbative contributions to the nucleon sea. Current phenomenological models that could explain some of these effects are reviewed.
A Polytropic Model of Quark Stars
Lai, X Y
2008-01-01
A polytropic quark star model was suggested in order to establish a general framework in which theoretical quark star models could be tested by observations. The key difference between polytropic quark and normal stars is related to the surface density, which is nonzero for the former but is zero for the latter. A quark star with self-confinement could then be very low massive, and be still gravitationally stable even if the polytropic index is greater than 3. The gravitational effect could be significant if quark star's mass is $\\gtrsim 0.01M_\\odot$, and substantial strain energy would then develop in a solid quark star during its accretion phase. The energy released during a star-quake could be as high as $\\sim 10^{48}$ ergs if the tangential pressure is $\\sim 10^{-4}$ higher than the radial one.
Gluonic Structure of the Constituent Quark
Kochelev, Nikolai; Zhang, Baiyang; Zhang, Pengming
2015-01-01
Based on both the constituent quark picture and the instanton model for QCD vacuum, we calculate the unpolarized and polarized gluon distributions in the constituent quark and in the nucleon. Our approach consists of the two main steps. At the first step, we calculate the gluon distributions inside the constituent quark generated by the perturbative quark-gluon interaction, the non-perturbative quark-gluon interaction, and the non-perturbative quark-gluon-pion anomalous chromomagnetic interaction. The non-perturbative interactions are related to the existence of the instantons, strong topological fluctuations of gluon fields, in the QCD vacuum. At the second step, the convolution model is applied to derive the gluon distributions in the nucleon. A very important role of the pion field in producing the unpolarized and the polarized gluon distributions in the hadrons is discovered. We discuss a possible solution of the proton spin problem.
Gluonic structure of the constituent quark
Kochelev, Nikolai; Lee, Hee-Jung; Zhang, Baiyang; Zhang, Pengming
2016-06-01
Based on both the constituent quark picture and the instanton model for QCD vacuum, we calculate the unpolarized and polarized gluon distributions in the constituent quark and in the nucleon. Our approach consists of the two main steps. At the first step, we calculate the gluon distributions inside the constituent quark generated by the perturbative quark-gluon interaction, the non-perturbative quark-gluon interaction, and the non-perturbative quark-gluon-pion anomalous chromomagnetic interaction. The non-perturbative interactions are related to the existence of the instantons, strong topological fluctuations of gluon fields, in the QCD vacuum. At the second step, the convolution model is applied to derive the gluon distributions in the nucleon. A very important role of the pion field in producing the unpolarized and the polarized gluon distributions in the hadrons is discovered. We discuss a possible solution of the proton spin problem.
Experimental test of the flavor independence of the quark-gluon coupling constant
International Nuclear Information System (INIS)
Reconstruction of charged Dsup(*)'s produced inclusively in e+e- annhilations at c.m. energies near 34.4 GeV is accomplished in the decay modes Dsup(*+) -> D0π+ -> K-π+π0π+ and Dsup(*+) -> D0π+ -> K-π+π-π+π+ and their charge conjugates. Using these and previously reported Dsup(*+) -> D0π+ -> K-π+π+ and Dsup(*+) -> D0π+ -> K-π+π++ missing π0 channels we present evidence for hard gluon bremsstrahlung from charm quarks and show that the ratio of the quark-gluon coupling constant of charm quarks to the coupling constant obtained in the average hadronic event, αsub(s)sup(c)/αsub(s) = 1.00 +- 0.20 +- 0.20. Our result provides evidence that the quark-gluon coupling constant is independent of flavor. (orig.)
Charm and beauty quark masses in the MMHT2014 global PDF analysis
Harland-Lang, L A; Motylinski, P; Thorne, R S
2016-01-01
We investigate the variation in the MMHT2014 PDFs when we allow the heavy quark masses $m_c$ and $m_b$ to vary away from their default values. We make PDF sets available in steps of $\\Delta m_c =0.05~{\\rm GeV}$ and $\\Delta m_b =0.25~{\\rm GeV}$, and present the variation in the PDFs and in the predictions. We examine the comparison to the HERA data on charm and beauty structure functions and note that in each case the heavy quark data, and the inclusive data, have a slight preference for lower masses than our default values. We provide PDF sets with 3 and 4 active quark flavours, as well as the standard value of 5 flavours. We use the pole mass definition of the quark masses, as in the default MMHT2014 analysis, but briefly comment on the $\\overline{\\rm MS}$ definition.
Charm and beauty quark masses in the MMHT2014 global PDF analysis
Harland-Lang, L. A.; Martin, A. D.; Motylinski, P.; Thorne, R. S.
2016-01-01
We investigate the variation in the MMHT2014 PDFs when we allow the heavy-quark masses m_c and m_b to vary away from their default values. We make PDF sets available in steps of Δ m_c =0.05 GeV and Δ m_b =0.25 GeV, and present the variation in the PDFs and in the predictions. We examine the comparison to the HERA data on charm and beauty structure functions and note that in each case the heavy-quark data, and the inclusive data, have a slight preference for lower masses than our default values. We provide PDF sets with three and four active quark flavours, as well as the standard value of five flavours. We use the pole mass definition of the quark masses, as in the default MMHT2014 analysis, but briefly comment on the overline{MS} definition.
Charm and beauty quark masses in the MMHT2014 global PDF analysis
Energy Technology Data Exchange (ETDEWEB)
Harland-Lang, L.A.; Motylinski, P.; Thorne, R.S. [University College London, Department of Physics and Astronomy, London (United Kingdom); Martin, A.D. [Durham University, Institute for Particle Physics Phenomenology, Durham (United Kingdom)
2016-01-15
We investigate the variation in the MMHT2014 PDFs when we allow the heavy-quark masses m{sub c} and m{sub b} to vary away from their default values.Wemake PDF sets available in steps of Δm{sub c} = 0.05 GeV and Δm{sub b} = 0.25 GeV, and present the variation in the PDFs and in the predictions. We examine the comparison to the HERA data on charm and beauty structure functions and note that in each case the heavy-quark data, and the inclusive data, have a slight preference for lower masses than our default values.We provide PDF sets with three and four active quark flavours, as well as the standard value of five flavours. We use the pole mass definition of the quark masses, as in the default MMHT2014 analysis, but briefly comment on the MS definition. (orig.)
Charm and beauty quark masses in the MMHT2014 global PDF analysis
Energy Technology Data Exchange (ETDEWEB)
Harland-Lang, L. A. [Department of Physics and Astronomy, University College London, WC1E 6BT, London (United Kingdom); Martin, A. D. [Institute for Particle Physics Phenomenology, Durham University, DH1 3LE, Durham (United Kingdom); Motylinski, P.; Thorne, R. S., E-mail: thorne@hep.ucl.ac.uk [Department of Physics and Astronomy, University College London, WC1E 6BT, London (United Kingdom)
2016-01-06
We investigate the variation in the MMHT2014 PDFs when we allow the heavy-quark masses m{sub c} and m{sub b} to vary away from their default values. We make PDF sets available in steps of Δm{sub c}=0.05 GeV and Δm{sub b}=0.25 GeV, and present the variation in the PDFs and in the predictions. We examine the comparison to the HERA data on charm and beauty structure functions and note that in each case the heavy-quark data, and the inclusive data, have a slight preference for lower masses than our default values. We provide PDF sets with three and four active quark flavours, as well as the standard value of five flavours. We use the pole mass definition of the quark masses, as in the default MMHT2014 analysis, but briefly comment on the (MS)-bar definition.
Some Aspects of Three-Quark Potentials
Andreev, Oleg
2015-01-01
We use gauge-string duality to analytically evaluate the expectation value of a baryonic Wilson loop in a SU(3) pure gauge theory. We then discuss three aspects of a static three-quark potential: an aspect of universality which concerns properties independent of a geometric configuration of quarks; a heavy diquark structure; and a relation between the three and two-quark potentials.
Pretzelosity TMD and Quark Orbital Angular Momentum
Lorce, Cédric; Pasquini, B.
2015-01-01
We study the connection between the quark orbital angular momentum and the pretzelosity transverse-momentum dependent parton distribution function. We discuss the origin of this relation in quark models, identifying as key ingredient for its validity the assumption of spherical symmetry for the nucleon in its rest frame. Finally we show that the individual quark contributions to the orbital angular momentum obtained from this relation can not be interpreted as the intrinsic contributions, but...
Quark liberation and coalescence at CERN SPS
Zimányi, J; Csörgö, T; Lévai, Peter
2000-01-01
The linear coalescence approach to hadronization of quark matter is shown to have problems with strangeness conservation in a baryon rich environment. The simplest correct quark counting is shown to coincide with the non-linear algebraic coalescence rehadronization model, ALCOR. We argue that experimental facts agree with the assumption that quark degrees of freedom are liberated before hadron formation in 158 AGeV central Pb+Pb collisions at CERN SPS. (13 refs).
Baryon masses with improved staggered quarks
Bernard, C; DeTar, C; Gottlieb, S; Heller, U M; Hetrick, J E; Levkova, L; Osborn, J; Renner, D B; Sugar, R; Toussaint, D
2007-01-01
The MILC collaboration's simulations with improved staggered quarks are being extended with runs at a lattice spacing of 0.06 fm with quark masses down to one tenth the strange quark mass. We give a brief introduction to these new simulations and the determination of the lattice spacing. Then we combine these new runs with older results to study the masses of the nucleon and the Omega minus in the continuum and chiral limits.
Baryon Ratios in Quark-Gluon Plasma
Institute of Scientific and Technical Information of China (English)
MAZhong-Biao; MIAOHong; GAOChong-Shou
2003-01-01
A way to calculate ratios of baryon produced from quark gluon plasma in relativistic heavy ion collisions is presented. It is assumed that at the beginning of the hadronlzation there are diquarks and anti-diquarks in the quark matter. The number of three-quark states is distributed between the corresponding multiplets, and hadronic decays are taken into account. The results are shown at last.
Quark Nova Model for Fast Radio Bursts
Shand, Zachary; Ouyed, Amir; Koning, Nico; Ouyed, Rachid
2015-01-01
FRBs are puzzling, millisecond, energetic radio transients with no discernible source; observations show no counterparts in other frequency bands. The birth of a quark star from a parent neutron star experiencing a quark nova - previously thought undetectable when born in isolation - provides a natural explanation for the emission characteristics of FRBs. The generation of unstable r-process elements in the quark nova ejecta provides millisecond exponential injection of electrons into the sur...
Correlations in hot and dense quark matter
Mattiello, S.; Beyer, M.; Frederico, T.; Weber, H. J.
2001-01-01
We present a relativistic three-body equation to investigate three-quark clusters in hot and dense quark matter. To derive such an equation we use the Dyson equation approach. The equation systematically includes the Pauli blocking factors as well as the self energy corrections of quarks. Special relativity is realized through the light front form. Presently we use a zero-range force and investigate the Mott transition.
Radiatively induced Quark and Lepton Mass Model
Nomura, Takaaki
2016-01-01
We propose a radiatively induced quark and lepton mass model in the first and second generation with extra $U(1)$ gauge symmetry and vector-like fermions. Then we analyze the allowed regions which simultaneously satisfy the FCNCs for the quark sector, LFVs including $\\mu-e$ conversion, the quark mass and mixing, and the lepton mass and mixing. Also we estimate the typical value for the $(g-2)_\\mu$ in our model.
Recurrence formulae for lepton and quark generations
International Nuclear Information System (INIS)
Some phenomenological recurrence equations suggested recently for lepton and quark generations are reviewed. They predict the charged lepton of the fourth generation at 28.5 GeV and the up and down quarks of that hypothetic generation at about 250 GeV and 62 GeV, respectively. The top quark, i.e. the up quark of the third generation, is predicted at about 20 GeV. In the appendix a toy model with a statistical interpretation of mass spectral law is described. (author)
Quark Wigner distributions and orbital angular momentum
International Nuclear Information System (INIS)
We study the Wigner functions of the nucleon which provide multidimensional images of the quark distributions in phase space. These functions can be obtained through a Fourier transform in the transverse space of the generalized transverse-momentum dependent parton distributions. They depend on both the transverse position and the three-momentum of the quark relative to the nucleon, and therefore combine in a single picture all the information contained in the generalized parton distributions and the transverse-momentum dependent parton distributions. We focus the discussion on the distributions of unpolarized/longitudinally polarized quark in an unpolarized/longitudinally polarized nucleon. In this way, we can study the role of the orbital angular momentum of the quark in shaping the nucleon and its correlations with the quark and nucleon polarizations. The quark orbital angular momentum is also calculated from its phase-space average weighted with the Wigner distribution of unpolarized quarks in a longitudinally polarized nucleon. The corresponding results obtained within different light-cone quark models are compared with alternative definitions of the quark orbital angular momentum, as given in terms of generalized parton distributions and transverse-momentum dependent parton distributions.
Quarks and gluons at hadron colliders
International Nuclear Information System (INIS)
Data from proton-antiproton collisions at high energy provide important information on constraining the quark and gluon distributions in the nucleon and place limits on quark substructure. The S asymmetry data constrains the slope of the d/u quark distributions and significantly reduces the systematic error on the extracted value of the W mass. Drell-Yan data at high invariant mass provides strong limits on quark substructure. Information on αs and the gluon distributions can be extracted from high PT jet data and direct photons
Planets orbiting Quark Nova compact remnants
Keränen, P.; Ouyed, R.
2003-01-01
We explore planet formation in the Quark Nova scenario. If a millisecond pulsar explodes as a Quark Nova, a protoplanetary disk can be formed out of the metal rich fall-back material. The propeller mechanism transfers angular momentum from the born quark star to the disk that will go through viscous evolution with later plausible grain condensation and planet formation. As a result, earth-size planets on circular orbits may form within short radii from the central quark star. The planets in t...
Measurements and searches with top quarks
Energy Technology Data Exchange (ETDEWEB)
Peters, Reinhild Yvonne; /Wuppertal U.
2008-10-01
In 1995 the last missing member of the known families of quarks, the top quark, was discovered by the CDF and D0 experiments at the Tevatron, a proton-antiproton collider at Fermilab near Chicago. Until today, the Tevatron is the only place where top quarks can be produced. The determination of top quark production and properties is crucial to understand the Standard Model of particle physics and beyond. The most striking property of the top quark is its mass--of the order of the mass of a gold atom and close to the electroweak scale--making the top quark not only interesting in itself but also as a window to new physics. Due to the high mass, much higher than of any other known fermion, it is expected that the top quark plays an important role in electroweak symmetry breaking, which is the most prominent candidate to explain the mass of particles. In the Standard Model, electroweak symmetry breaking is induced by one Higgs field, producing one additional physical particle, the Higgs boson. Although various searches have been performed, for example at the Large Electron Positron Collider (LEP), no evidence for the Higgs boson could yet be found in any experiment. At the Tevatron, multiple searches for the last missing particle of the Standard Model are ongoing with ever higher statistics and improved analysis techniques. The exclusion or verification of the Higgs boson can only be achieved by combining many techniques and many final states and production mechanisms. As part of this thesis, the search for Higgs bosons produced in association with a top quark pair (t{bar t}H) has been performed. This channel is especially interesting for the understanding of the coupling between Higgs and the top quark. Even though the Standard Model Higgs boson is an attractive candidate, there is no reason to believe that the electroweak symmetry breaking is induced by only one Higgs field. In many models more than one Higgs boson are expected to exist, opening even more channels
Single top quark production with CMS
Directory of Open Access Journals (Sweden)
Piccolo Davide
2013-11-01
Full Text Available Measurements of single top quark production performed using the CMS experiment [1] data collected in 2011 at centre-of-mass energies of 7 TeV and in 2012 at 8 TeV, are presented. The cross sections for the electroweak production of single top quarks in the t-channel and in association with W-bosons is measured and the results are used to place constraints on the CKM matrix element Vtb. Measurements of top quark properties in single top quark production are also presented. The results include the measurement of the charge ratio in the single top t-channel.
Quark color algebra in Adler's chromostatics
International Nuclear Information System (INIS)
I study quark color charge algebras and investigate general outer products which satisfy the Jacobi identity and inner products which are consistent with the trace condition. The two-quark case is treated in detail. For three or more quarks, only two kinds of outer products are possible, neither of which satisfies the restricted trace condition in the simplest formulation of the color charge algebra. A three-copy theory is constructed so that the restricted trace condition is satisfied in the three-quark case
Single Top Quark Production at the Tevatron
Peters, Yvonne
2012-01-01
While the heaviest known elementary particle, the top quark, has been discovered in 1995 by the CDF and D0 collaborations in ttbar events, it took 14 more years until the observation of single top quark production. In this article, we discuss recent studies of single top quark production by the CDF and D0 collaborations at the Tevatron. In particular, we present the measurement of single top quark s- and t-channel production combined, the first observation of t-channel production, the simultaneous measurement of s- and t-channel production cross sections as well as the extraction of the CMK matrix element |Vtb}|.
Measurements and searches with top quarks
Energy Technology Data Exchange (ETDEWEB)
Peters, Reinhild Yvonne [Univ. of Wuppertal (Germany)
2008-08-01
In 1995 the last missing member of the known families of quarks, the top quark, was discovered by the CDF and D0 experiments at the Tevatron, a proton-antiproton collider at Fermilab near Chicago. Until today, the Tevatron is the only place where top quarks can be produced. The determination of top quark production and properties is crucial to understand the Standard Model of particle physics and beyond. The most striking property of the top quark is its mass--of the order of the mass of a gold atom and close to the electroweak scale--making the top quark not only interesting in itself but also as a window to new physics. Due to the high mass, much higher than of any other known fermion, it is expected that the top quark plays an important role in electroweak symmetry breaking, which is the most prominent candidate to explain the mass of particles. In the Standard Model, electroweak symmetry breaking is induced by one Higgs field, producing one additional physical particle, the Higgs boson. Although various searches have been performed, for example at the Large Electron Positron Collider (LEP), no evidence for the Higgs boson could yet be found in any experiment. At the Tevatron, multiple searches for the last missing particle of the Standard Model are ongoing with ever higher statistics and improved analysis techniques. The exclusion or verification of the Higgs boson can only be achieved by combining many techniques and many final states and production mechanisms. As part of this thesis, the search for Higgs bosons produced in association with a top quark pair (t$\\bar{t}$H) has been performed. This channel is especially interesting for the understanding of the coupling between Higgs and the top quark. Even though the Standard Model Higgs boson is an attractive candidate, there is no reason to believe that the electroweak symmetry breaking is induced by only one Higgs field. In many models more than one Higgs boson are expected to exist, opening even more
Transversity of quarks in a nucleon
Indian Academy of Sciences (India)
K Bora; D K Choudhury
2003-11-01
The transversity distribution of quarks in a nucleon is one of the three fundamental distributions, that characterize nucleon’s properties in hard scattering processes at leading twist (twist 2). It measures the distribution of quark transverse spin in a nucleon polarized transverse to its (inﬁnite) momentum. It is a chiral-odd twist-two distribution function – gluons do not couple to it. Quarks in a nucleon/hadron are relativistically bound and transversity is a measure of the relativistic nature of bound quarks in a nucleon. In this work, we review some important aspects of this less familiar distribution function which has not been measured experimentally so far.
CP Violation in Single Top Quark Production
Energy Technology Data Exchange (ETDEWEB)
Geng, Weigang [Michigan State Univ., East Lansing, MI (United States)
2012-01-01
We present a search for CP violation in single top quark production with the DØ experiment at the Tevatron proton-antiproton collider. CP violation in the top electroweak interaction results in different single top quark production cross sections for top and antitop quarks. We perform the search in the single top quark final state using 5.4 fb^{-1} of data, in the s-channel, t-channel, and for both combined. At this time, we do not see an observable CP asymmetry.
Quarks and gluons in a magnetic field
Watson, Peter
2013-01-01
The quark gap equation under the rainbow truncation, with two versions of a phenomenological one-gluon exchange interaction and in the presence of a uniform magnetic field is considered. It is argued that in order to describe the quark condensate in the limit of vanishing magnetic fields, one must sum over the Landau levels. The resulting chiral quark condensate rises quadratically for small magnetic fields and linearly for large fields, in qualitative agreement with various recent lattice results. It is observed that when discussing quarks, the magnitude of the magnetic field must be considered relative to the scale of the strong interaction.
Pseudoscalar meson physics with four dynamical quarks
Bazavov, A; Bouchard, C; DeTar, C; Du, D; El-Khadra, A X; Foley, J; Freeland, E D; Gamiz, E; Gottlieb, Steven; Heller, U M; Hetrick, J E; Kim, J; Kronfeld, A S; Laiho, J; Levkova, L; Lightman, M; Mackenzie, P B; Neil, E T; Oktay, M; Simone, J N; Sugar, R L; Toussaint, D; Van de Water, R S; Zhou, R
2012-01-01
We present preliminary results for light, strange and charmed pseudoscalar meson physics from simulations using four flavors of dynamical quarks with the highly improved staggered quark (HISQ) action. These simulations include lattice spacings ranging from 0.15 to 0.06 fm, and sea-quark masses both above and at their physical value. The major results are charm meson decay constants f_D, f_{D_s} and f_{D_s}/f_D and ratios of quark masses. This talk will focus on our procedures for finding the decay constants on each ensemble, the continuum extrapolation, and estimates of systematic error.
Factorization versus duality in nonleptonic decays a quark model approach
Le Yaouanc, A; Pène, O; Raynal, J C; Le Yaouanc, A; Oliver, L; Pene, O; Raynal, J C
1995-01-01
We study in a quark model the contradiction between factorization and duality found in nonleptonic decays at next to leading order in 1/N_c, concentrating on quark exchange mechanism. The contradiction originates in the fact that the standard factorization assumption approximates the asymptotic final states by a non-orthogonal set of states, thus leading to an overcounting of the decay probability. We consider a system with two heavy quarks treated as classical color sources with constant velocity, and two mass-degenerate antiquarks. Exploiting permutation symmetry in an adiabatic approximation, we find that final state interaction restores duality. Three O(1/N_c) effects are exhibited: i) a proper treatment of orthogonality yields a global correction 1/N_c\\to 1/2N_c within a generalized factorization \\`a la BSW, (such a factor was present in an Ansatz by Shifman), ii) the distorsion of the meson wave functions at the time of the weak decay, iii) relative phases generated by the later evolution. The latter ef...
Heavy quark mass effects and improved tests of the flavour independence of strong interactions
Burrows, P N
1998-01-01
A review is given of latest results on tests of the flavour independence of strong interactions. Heavy quark mass effects are evident in the data and are now taken into account at next-to-leading order in QCD perturbation theory. The strong-coupling ratios alpha_s^b/alpha_s^uds and alpha_s^c/alpha_s^uds are found to be consistent with unity. Determinations of the b-quark mass m_b(M_Z) are discussed.
Soft Contribution to Quark-Quark Scattering Induced by an Anomalous Chromomagnetic Interaction
Kochelev, N.
2006-01-01
We calculate the soft contribution to high energy quark-quark scattering that arises from an instanton-induced quark anomalous chromomagnetic moment. We demonstrate that this is a large contribution, which cannot be neglected for transverse momenta of a few GeV. We discuss the influence of this effect on inclusive particle production.
Quark Physics without Quarks: A Review of Recent Developments in S-Matrix Theory.
Capra, Fritjof
1979-01-01
Reviews the developments in S-matrix theory over the past five years which have made it possible to derive results characteristic of quark models without any need to postulate the existence of physical quarks. In the new approach, the quark patterns emerge as a consequence of combining the general S-matrix principles with the concept of order.…
The quark revolution and the ZGS - new quarks physics since the ZGS
International Nuclear Information System (INIS)
Overwhelming experimental evidence for quarks as real physical constituents of hadrons along with the QCD analogs of the Balmer Formula, Bohr Atom and Schroedinger Equation already existed in 1966 but was dismissed as heresy. ZGS experiments played an important role in the quark revolution. This role is briefly reviewed and subsequent progress in quark physics is described
The quark revolution and the ZGS - new quarks physics since the ZGS
Energy Technology Data Exchange (ETDEWEB)
Lipkin, H.J. [Weizmann Institute of Science, Rehovot (Israel)]|[Tel Aviv Univ. (Israel)
1994-12-31
Overwhelming experimental evidence for quarks as real physical constituents of hadrons along with the QCD analogs of the Balmer Formula, Bohr Atom and Schroedinger Equation already existed in 1966 but was dismissed as heresy. ZGS experiments played an important role in the quark revolution. This role is briefly reviewed and subsequent progress in quark physics is described.
Searches for new quarks and leptons in Z boson decays
Energy Technology Data Exchange (ETDEWEB)
Van Kooten, R.J.
1990-06-01
Searches for the decay of Z bosons into pairs of new quarks and leptons in a data sample including 455 hadronic Z decays are presented. The Z bosons were produced in electon-positron annihilations at the SLAC Linear Collider operating in the center-of-mass energy range from 89.2 to 93.0 GeV. The Standard Model provides no prediction for fermion masses and does not exclude new generations of fermions. The existence and masses of these new particles may provide valuable information to help understand the pattern of fermion masses, and physics beyond the Standard Model. Specific searches for top quarks and sequential fourth generation charge--1/3(b{prime}) quarks are made considering a variety of possible standard and non-standard decay modes. In addition, searches for sequential fourth generation massive neutrinos {nu}{sub 4} and their charged lepton partners L{sup {minus}} are pursued. The {nu}{sub 4} may be stable or decay through mixing to the lighter generations. The data sample is examined for new particle topologies of events with high-momentum isolated tracks, high-energy isolated photons, spherical event shapes, and detached vertices. No evidence is observed for the production of new quarks and leptons. 95% confidence lower mass limits of 40.7 GeV/c{sup 2} for the top quark and 42.0 GeV/c{sup 2} for the b{prime}-quark mass are obtained regardless of the branching fractions to the considered decay modes. A significant range of mixing matrix elements of {nu}{sub 4} to other generation neutrinos for a {nu}{sub 4} mass from 1 GeV/c{sup 2} to 43 GeV/c{sup 2} is excluded at 95% confidence level. Measurements of the upper limit of the invisible width of the Z exclude additional values of the {nu}{sub 4} mass and mixing matrix elements, and also permit the exclusion of a region in the L{sup {minus}} mass versus {nu}{sub 4} mass plane.
Identification of beauty and charm quark jets at LHCb
International Nuclear Information System (INIS)
Identification of jets originating from beauty and charm quarks is important for measuring Standard Model processes and for searching for new physics. The performance of algorithms developed to select b- and c-quark jets is measured using data recorded by LHCb from proton-proton collisions at √s = 7 TeV in 2011 and at √s = 8 TeV in 2012. The efficiency for identifying a b(c) jet is about 65%(25%) with a probability for misidentifying a light-parton jet of 0.3% for jets with transverse momentum pT > 20GeV and pseudorapidity 2.2 < η < 4.2. The dependence of the performance on the pT and η of the jet is also measured
Quark-lepton unification in SU(N>5)
Energy Technology Data Exchange (ETDEWEB)
Baaklini, N.S.
1980-04-01
We discuss a class of flavor-unification models for quarks and leptons based on the unitary groups SU(N>5). The spontaneous breaking of SU(N) is proposed to go via SU(3)/sub c/ x (SU(N-3) x U(1))/sub f/, then through successive stages down to SU(3)/sub c/ x SU(2) x U(1). Our models are anomaly-free and have the distinctive feature of associating several left-handed neutral partners to charged leptons. Quark-lepton assignments, weak currents, and fermion mass generation are discussed for SU(6), SU(7), and SU(8). The embedding of the SU(6) model in E/sub 6/ is also indicated. The SU(7) model is noted as the most economical three-generation model (49 chiral fields).
Identification of beauty and charm quark jets at LHCb
Aaij, Roel; Adinolfi, Marco; Affolder, Anthony; Ajaltouni, Ziad; Akar, Simon; Albrecht, Johannes; Alessio, Federico; Alexander, Michael; Ali, Suvayu; Alkhazov, Georgy; Alvarez Cartelle, Paula; Alves Jr, Antonio Augusto; Amato, Sandra; Amerio, Silvia; Amhis, Yasmine; An, Liupan; Anderlini, Lucio; Anderson, Jonathan; Andreotti, Mirco; Andrews, Jason; Appleby, Robert; Aquines Gutierrez, Osvaldo; Archilli, Flavio; d'Argent, Philippe; Artamonov, Alexander; Artuso, Marina; Aslanides, Elie; Auriemma, Giulio; Baalouch, Marouen; Bachmann, Sebastian; Back, John; Badalov, Alexey; Baesso, Clarissa; Baldini, Wander; Barlow, Roger; Barschel, Colin; Barsuk, Sergey; Barter, William; Batozskaya, Varvara; Battista, Vincenzo; Bay, Aurelio; Beaucourt, Leo; Beddow, John; Bedeschi, Franco; Bediaga, Ignacio; Bel, Lennaert; Belyaev, Ivan; Ben-Haim, Eli; Bencivenni, Giovanni; Benson, Sean; Benton, Jack; Berezhnoy, Alexander; Bernet, Roland; Bertolin, Alessandro; Bettler, Marc-Olivier; van Beuzekom, Martinus; Bien, Alexander; Bifani, Simone; Bird, Thomas; Birnkraut, Alex; Bizzeti, Andrea; Blake, Thomas; Blanc, Frédéric; Blouw, Johan; Blusk, Steven; Bocci, Valerio; Bondar, Alexander; Bondar, Nikolay; Bonivento, Walter; Borghi, Silvia; Borsato, Martino; Bowcock, Themistocles; Bowen, Espen Eie; Bozzi, Concezio; Braun, Svende; Brett, David; Britsch, Markward; Britton, Thomas; Brodzicka, Jolanta; Brook, Nicholas; Bursche, Albert; Buytaert, Jan; Cadeddu, Sandro; Calabrese, Roberto; Calvi, Marta; Calvo Gomez, Miriam; Campana, Pierluigi; Campora Perez, Daniel; Capriotti, Lorenzo; Carbone, Angelo; Carboni, Giovanni; Cardinale, Roberta; Cardini, Alessandro; Carniti, Paolo; Carson, Laurence; Carvalho Akiba, Kazuyoshi; Casanova Mohr, Raimon; Casse, Gianluigi; Cassina, Lorenzo; Castillo Garcia, Lucia; Cattaneo, Marco; Cauet, Christophe; Cavallero, Giovanni; Cenci, Riccardo; Charles, Matthew; Charpentier, Philippe; Chefdeville, Maximilien; Chen, Shanzhen; Cheung, Shu-Faye; Chiapolini, Nicola; Chrzaszcz, Marcin; Cid Vidal, Xabier; Ciezarek, Gregory; Clarke, Peter; Clemencic, Marco; Cliff, Harry; Closier, Joel; Coco, Victor; Cogan, Julien; Cogneras, Eric; Cogoni, Violetta; Cojocariu, Lucian; Collazuol, Gianmaria; Collins, Paula; Comerma-Montells, Albert; Contu, Andrea; Cook, Andrew; Coombes, Matthew; Coquereau, Samuel; Corti, Gloria; Corvo, Marco; Couturier, Benjamin; Cowan, Greig; Craik, Daniel Charles; Crocombe, Andrew; Cruz Torres, Melissa Maria; Cunliffe, Samuel; Currie, Robert; D'Ambrosio, Carmelo; Dalseno, Jeremy; David, Pieter; Davis, Adam; De Bruyn, Kristof; De Capua, Stefano; De Cian, Michel; De Miranda, Jussara; De Paula, Leandro; De Silva, Weeraddana; De Simone, Patrizia; Dean, Cameron Thomas; Decamp, Daniel; Deckenhoff, Mirko; Del Buono, Luigi; Déléage, Nicolas; Derkach, Denis; Deschamps, Olivier; Dettori, Francesco; Dey, Biplab; Di Canto, Angelo; Di Ruscio, Francesco; Dijkstra, Hans; Donleavy, Stephanie; Dordei, Francesca; Dorigo, Mirco; Dosil Suárez, Alvaro; Dossett, David; Dovbnya, Anatoliy; Dreimanis, Karlis; Dufour, Laurent; Dujany, Giulio; Dupertuis, Frederic; Durante, Paolo; Dzhelyadin, Rustem; Dziurda, Agnieszka; Dzyuba, Alexey; Easo, Sajan; Egede, Ulrik; Egorychev, Victor; Eidelman, Semen; Eisenhardt, Stephan; Eitschberger, Ulrich; Ekelhof, Robert; Eklund, Lars; El Rifai, Ibrahim; Elsasser, Christian; Ely, Scott; Esen, Sevda; Evans, Hannah Mary; Evans, Timothy; Falabella, Antonio; Färber, Christian; Farinelli, Chiara; Farley, Nathanael; Farry, Stephen; Fay, Robert; Ferguson, Dianne; Fernandez Albor, Victor; Ferrari, Fabio; Ferreira Rodrigues, Fernando; Ferro-Luzzi, Massimiliano; Filippov, Sergey; Fiore, Marco; Fiorini, Massimiliano; Firlej, Miroslaw; Fitzpatrick, Conor; Fiutowski, Tomasz; Fohl, Klaus; Fol, Philip; Fontana, Marianna; Fontanelli, Flavio; Forty, Roger; Francisco, Oscar; Frank, Markus; Frei, Christoph; Frosini, Maddalena; Fu, Jinlin; Furfaro, Emiliano; Gallas Torreira, Abraham; Galli, Domenico; Gallorini, Stefano; Gambetta, Silvia; Gandelman, Miriam; Gandini, Paolo; Gao, Yuanning; García Pardiñas, Julián; Garofoli, Justin; Garra Tico, Jordi; Garrido, Lluis; Gascon, David; Gaspar, Clara; Gastaldi, Ugo; Gauld, Rhorry; Gavardi, Laura; Gazzoni, Giulio; Geraci, Angelo; Gerick, David; Gersabeck, Evelina; Gersabeck, Marco; Gershon, Timothy; Ghez, Philippe; Gianelle, Alessio; Gianì, Sebastiana; Gibson, Valerie; Girard, Olivier Göran; Giubega, Lavinia-Helena; Gligorov, Vladimir; Göbel, Carla; Golubkov, Dmitry; Golutvin, Andrey; Gomes, Alvaro; Gotti, Claudio; Grabalosa Gándara, Marc; Graciani Diaz, Ricardo
2015-01-01
Identification of jets originating from beauty and charm quarks is important for measuring Standard Model processes and for searching for new physics. The performance of algorithms developed to select $b$- and $c$-quark jets is measured using data recorded by LHCb from proton-proton collisions at $\\sqrt{s}=7$ TeV in 2011 and at $\\sqrt{s}=8$ TeV in 2012. The efficiency for identifying a $b(c)$ jet is about 65%(25%) with a probability for misidentifying a light-parton jet of 0.3% for jets with transverse momentum $p_{\\rm T} > 20$ GeV and pseudorapidity $2.2 < \\eta < 4.2$. The dependence of the performance on the $p_{\\rm T}$ and $\\eta$ of the jet is also measured.
Quark Flavors as Entropy Ordered States of QCD
Pérez-Mercader, J
1993-01-01
We discuss a natural notion of entropy in quantum field theory and apply it to asymptotically free theories in their perturbative regimes. We then specialize to QCD and find that quark flavor states can be described as entropy--ordered states of QCD, and that the masses for the $s\\bar{s}$--state, charm, $c\\bar{c}$--state, bottom and $b\\bar{b}$--state can all be fitted by requiring that the entropy of each of these states be the same. The resulting Pearson correlation coefficient between theory and experiment is better than 0.99, and the known quark masses can be accounted for with less than an 8\\% error.
Identification of beauty and charm quark jets at LHCb
The LHCb Collaboration
2015-06-01
Identification of jets originating from beauty and charm quarks is important for measuring Standard Model processes and for searching for new physics. The performance of algorithms developed to select b- and c-quark jets is measured using data recorded by LHCb from proton-proton collisions at √s = 7 TeV in 2011 and at √s = 8 TeV in 2012. The efficiency for identifying a b(c) jet is about 65%(25%) with a probability for misidentifying a light-parton jet of 0.3% for jets with transverse momentum pT > 20GeV and pseudorapidity 2.2 < η < 4.2. The dependence of the performance on the pT and η of the jet is also measured.
Search for new heavy quarks in proton-antiproton collisions at √s=0.63 TeV
International Nuclear Information System (INIS)
We report on a search for new heavy quarks decaying semileptonically into muons, using 4.7 pb-1 of data taken during the CERN panti p collider runs in 1988 and 1989. The properties of isolated muons accompanied by jets are consistent with the predictions from the Standard Model but do not show a signal for a new heavy quark. Combining all the UA1 data (5.4 pb-1), lower mass limits are obtained at 60 GeV/c2 (95% CL) for the t-quark and 43 GeV/c2 (95% CL) for a fourth-generation charge-1/3 quark (b'-quark). (orig.)
Review of meson spectroscopy: quark states and glueballs
International Nuclear Information System (INIS)
A group of three lectures on hadron spectroscopy are presented. Topics covered include: light L = 0 mesons, light L = 1 mesons, antiquark antiquark quark quark exotics, a catalogue of higher quark antiquark excitations, heavy quarkonium, and glueballs
Measurement of parity violation in electron-quark scattering.
2014-02-01
Symmetry permeates nature and is fundamental to all laws of physics. One example is parity (mirror) symmetry, which implies that flipping left and right does not change the laws of physics. Laws for electromagnetism, gravity and the subatomic strong force respect parity symmetry, but the subatomic weak force does not. Historically, parity violation in electron scattering has been important in establishing (and now testing) the standard model of particle physics. One particular set of quantities accessible through measurements of parity-violating electron scattering are the effective weak couplings C2q, sensitive to the quarks' chirality preference when participating in the weak force, which have been measured directly only once in the past 40 years. Here we report a measurement of the parity-violating asymmetry in electron-quark scattering, which yields a determination of 2C2u - C2d (where u and d denote up and down quarks, respectively) with a precision increased by a factor of five relative to the earlier result. These results provide evidence with greater than 95 per cent confidence that the C2q couplings are non-zero, as predicted by the electroweak theory. They lead to constraints on new parity-violating interactions beyond the standard model, particularly those due to quark chirality. Whereas contemporary particle physics research is focused on high-energy colliders such as the Large Hadron Collider, our results provide specific chirality information on electroweak theory that is difficult to obtain at high energies. Our measurement is relatively free of ambiguity in its interpretation, and opens the door to even more precise measurements in the future. PMID:24499917
Measurement of parity violation in electron–quark scattering
Energy Technology Data Exchange (ETDEWEB)
Wang, D.; Pan, K.; Subedi, R.; Deng, X.; Ahmed, Z.; Allada, K.; Aniol, K. A.; Armstrong, D. S.; Arrington, J.; Bellini, V.; Beminiwattha, R.; Benesch, J.; Benmokhtar, F.; Bertozzi, W.; Camsonne, A.; Canan, M.; Cates, G. D.; Chen, J.-P.; Chudakov, E.; Cisbani, E.; Dalton, M. M.; de Jager, C. W.; De Leo, R.; Deconinck, W.; Deur, A.; Dutta, C.; El Fassi, L.; Erler, J.; Flay, D.; Franklin, G. B.; Friend, M.; Frullani, S.; Garibaldi, F.; Gilad, S.; Giusa, A.; Glamazdin, A.; Golge, S.; Grimm, K.; Hafidi, K.; Hansen, J.-O.; Higinbotham, D. W.; Holmes, R.; Holmstrom, T.; Holt, R. J.; Huang, J.; Hyde, C. E.; Jen, C. M.; Jones, D.; Kang, Hoyoung; King, P. M.; Kowalski, S.; Kumar, K. S.; Lee, J. H.; LeRose, J. J.; Liyanage, N.; Long, E.; McNulty, D.; Margaziotis, D. J.; Meddi, F.; Meekins, D. G.; Mercado, L.; Meziani, Z.-E.; Michaels, R.; Mihovilovic, M.; Muangma, N.; Myers, K. E.; Nanda, S.; Narayan, A.; Nelyubin, V.; Nuruzzaman,; Oh, Y.; Parno, D.; Paschke, K. D.; Phillips, S. K.; Qian, X.; Qiang, Y.; Quinn, B.; Rakhman, A.; Reimer, P. E.; Rider, K.; Riordan, S.; Roche, J.; Rubin, J.; Russo, G.; Saenboonruang, K.; Saha, A.; Sawatzky, B.; Shahinyan, A.; Silwal, R.; Sirca, S.; Souder, P. A.; Suleiman, R.; Sulkosky, V.; Sutera, C. M.; Tobias, W. A.; Urciuoli, G. M.; Waidyawansa, B.; Wojtsekhowski, B.; Ye, L.; Zhao, B.; Zheng, X.
2014-02-05
Symmetry permeates nature and is fundamental to all laws of physics. One example is parity (mirror) symmetry, which implies that flipping left and right does not change the laws of physics. Laws for electromagnetism, gravity and the subatomic strong force respect parity symmetry, but the subatomic weak force does not. Historically, parity violation in electron scattering has been important in establishing (and now testing) the standard model of particle physics. One particular set of quantities accessible through measurements of parity-violating electron scattering are the effective weak couplings C2q, sensitive to the quarks chirality preference when participating in the weak force, which have been measured directly3, 4 only once in the past 40?years. Here we report a measurement of the parity-violating asymmetry in electron-quark scattering, which yields a determination of 2C2u???C2d (where u and d denote up and down quarks, respectively) with a precision increased by a factor of five relative to the earlier result. These results provide evidence with greater than 95 per cent confidence that the C2q couplings are non-zero, as predicted by the electroweak theory. They lead to constraints on new parity-violating interactions beyond the standard model, particularly those due to quark chirality. Whereas contemporary particle physics research is focused on high-energy colliders such as the Large Hadron Collider, our results provide specific chirality information on electroweak theory that is difficult to obtain at high energies. Our measurement is relatively free of ambiguity in its interpretation, and opens the door to even more precise measurements in the future.
Effective Lagrangian approach to multi-quark interactions
Osipov, A A; Blin, A H
2014-01-01
In this workshop we have presented the results obtained in the three-flavour ($N_f=3$) Nambu--Jona-Lasinio model Lagrangian which includes all non-derivative vertices at NLO in the $1/N_c$ expansion of spin zero multi-quark interactions. In particular the role played by the explicit chiral symmetry breaking interactions has been discussed in comparison with previous model Lagrangians.
Measurement of parity violation in electron-quark scattering
The Jefferson Lab Pvdis Collaboration; Wang, D.; Pan, K.; Subedi, R.; Deng, X.; Ahmed, Z.; Allada, K.; Aniol, K. A.; Armstrong, D. S.; Arrington, J.; Bellini, V.; Beminiwattha, R.; Benesch, J.; Benmokhtar, F.; Bertozzi, W.; Camsonne, A.; Canan, M.; Cates, G. D.; Chen, J.-P.; Chudakov, E.; Cisbani, E.; Dalton, M. M.; de Jager, C. W.; de Leo, R.; Deconinck, W.; Deur, A.; Dutta, C.; El Fassi, L.; Erler, J.; Flay, D.; Franklin, G. B.; Friend, M.; Frullani, S.; Garibaldi, F.; Gilad, S.; Giusa, A.; Glamazdin, A.; Golge, S.; Grimm, K.; Hafidi, K.; Hansen, J.-O.; Higinbotham, D. W.; Holmes, R.; Holmstrom, T.; Holt, R. J.; Huang, J.; Hyde, C. E.; Jen, C. M.; Jones, D.; Kang, Hoyoung; King, P. M.; Kowalski, S.; Kumar, K. S.; Lee, J. H.; Lerose, J. J.; Liyanage, N.; Long, E.; McNulty, D.; Margaziotis, D. J.; Meddi, F.; Meekins, D. G.; Mercado, L.; Meziani, Z.-E.; Michaels, R.; Mihovilovic, M.; Muangma, N.; Myers, K. E.; Nanda, S.; Narayan, A.; Nelyubin, V.; Nuruzzaman; Oh, Y.; Parno, D.; Paschke, K. D.; Phillips, S. K.; Qian, X.; Qiang, Y.; Quinn, B.; Rakhman, A.; Reimer, P. E.; Rider, K.; Riordan, S.; Roche, J.; Rubin, J.; Russo, G.; Saenboonruang, K.; Saha, A.; Sawatzky, B.; Shahinyan, A.; Silwal, R.; Sirca, S.; Souder, P. A.; Suleiman, R.; Sulkosky, V.; Sutera, C. M.; Tobias, W. A.; Urciuoli, G. M.; Waidyawansa, B.; Wojtsekhowski, B.; Ye, L.; Zhao, B.; Zheng, X.
2014-02-01
Symmetry permeates nature and is fundamental to all laws of physics. One example is parity (mirror) symmetry, which implies that flipping left and right does not change the laws of physics. Laws for electromagnetism, gravity and the subatomic strong force respect parity symmetry, but the subatomic weak force does not. Historically, parity violation in electron scattering has been important in establishing (and now testing) the standard model of particle physics. One particular set of quantities accessible through measurements of parity-violating electron scattering are the effective weak couplings C2q, sensitive to the quarks' chirality preference when participating in the weak force, which have been measured directly only once in the past 40years. Here we report a measurement of the parity-violating asymmetry in electron-quark scattering, which yields a determination of 2C2u-C2d (where u and d denote up and down quarks, respectively) with a precision increased by a factor of five relative to the earlier result. These results provide evidence with greater than 95 per cent confidence that the C2q couplings are non-zero, as predicted by the electroweak theory. They lead to constraints on new parity-violating interactions beyond the standard model, particularly those due to quark chirality. Whereas contemporary particle physics research is focused on high-energy colliders such as the Large Hadron Collider, our results provide specific chirality information on electroweak theory that is difficult to obtain at high energies. Our measurement is relatively free of ambiguity in its interpretation, and opens the door to even more precise measurements in the future.
Quark masses and mixing angles in heterotic orbifold models
Ko, P; Park, J; Ko, Pyungwon; Kobayashi, Tatsuo; Park, Jae-hyeon
2004-01-01
We study systematically the possibility for realizing realistic values of quark mass ratios $m_c/m_t$ and $m_s/m_b$ and the mixing angle $V_{cb}$ by using only renormalizable Yukawa couplings derived from heterotic orbifold models. We assume one pair of up and down sector Higgs fields. We show realistic examples including hierarchical and democratic forms of Yukawa matrices.
Charm production asymmetries from heavy-quark recombination
Mehen, Thomas
2003-01-01
Charm asymmetries in fixed-target hadroproduction experiments are sensitive to power corrections to the QCD factorization theorem for heavy quark production. A power correction called heavy-quark recombination has recently been proposed to explain these asymmetries. In heavy-quark recombination, a light quark or antiquark participates in a hard scattering which produces a charm-anticharm quark pair. The light quark or antiquark emerges from the scattering with small momentum in the rest frame...
Nonperturbative results on the quark-gluon vertex
Aguilar, A. C.; Binosi, D.; Cardona, J. C.; Papavassiliou, J.
2013-01-01
We present analytical and numerical results for the Dirac form factor of the quark-gluon vertex in the quark symmetric limit, where the incoming and outgoing quark momenta have the same magnitude but opposite sign. To accomplish this, we compute the relevant components of the quark-ghost scattering kernel at the one-loop dressed approximation, using as basic ingredients the full quark propagator, obtained as a solution of the quark gap equation, and the gluon propagator and ghost dressing fun...
Nonperturbative Corrections to One Gluon Exchange Quark Potentials
Yang, J. J.; Shen, H Q; Li, G L; Huang, T; Shen, P. N.
1998-01-01
The leading nonperturbative QCD corrections to the one gluon exchange quark-quark, quark-antiquark and $q \\bar{q}$ pair-excitation potentials are derived by using a covariant form of nonlocal two-quark and two-gluon vacuum expectation values. Our numerical calculation indicates that the correction of quark and gluon condensates to the quark-antiquark potential improves the heavy quarkonium spectra to some degree.
Second quantization approach to composite hadron interactions in quark models
Hadjimichef, D.; Krein, G.; Szpigel, S.; da Veiga, J. S.
1995-01-01
Starting from the Fock space representation of hadron bound states in a quark model, a change of representation is implemented by a unitary transformation such that the composite hadrons are redescribed by elementary-particle field operators. Application of the unitary transformation to the microscopic quark Hamiltonian gives rise to effective hadron-hadron, hadron-quark, and quark-quark Hamiltonians. An effective baryon Hamiltonian is derived using a simple quark model. The baryon Hamiltonia...
Measurement of the top quark mass
Energy Technology Data Exchange (ETDEWEB)
Varnes, E.W.
1997-12-31
This dissertation describes the measurement of the top quark mass m{sub t} using events recorded during a 125 pb{sup -1} exposure of the D0 detector to {radical}s=1.8 TeV {anti p}p collisions. Six events consistent with the hypothesis t{anti t} {yields} bW{sup +}, {anti b}W{sup -} {yields} b{anti l}{nu}, {anti b}l{anti {nu}} form the dilepton sample. The kinematics of such events may be reconstructed for any assumed mt, and the likelihood of each such solution evaluated. A measurement of m{sub t} based on these relative solution likelihoods gives m{sub t} = 169.9 {+-} 14.8 (stat.) {+-} 3. 8 (syst.) GeV/c{sup 2}. A 2C kinematic fit is performed on a sample of 77 events consistent with t{anti t} {yields} bW{sup +}, {anti b}W{sup -} {yields} b{anti l}{nu}, {anti b}q{anti q} , and this, in combination with an estimate on the likelihood that each event is top, yields m{sub t} = 173.3 {+-} 5.6 (stat.) {+-} 6.2 (syst.) GeV/c{sup 2} . A combination of these two measurements gives m{sub t} = 173.1 {+-} 5.2 (stat.) {+-} 5.7 (syst.) GeV/c{sup 2}.
Measurement of the top quark mass
International Nuclear Information System (INIS)
This dissertation describes the measurement of the top quark mass mt using events recorded during a 125 pb-1 exposure of the D0 detector to √s=1.8 TeV anti pp collisions. Six events consistent with the hypothesis t anti t → bW+, anti bW- → b anti lν, anti bl anti ν form the dilepton sample. The kinematics of such events may be reconstructed for any assumed mt, and the likelihood of each such solution evaluated. A measurement of mt based on these relative solution likelihoods gives mt = 169.9 ± 14.8 (stat.) ± 3. 8 (syst.) GeV/c2. A 2C kinematic fit is performed on a sample of 77 events consistent with t anti t → bW+, anti bW- → b anti lν, anti bq anti q , and this, in combination with an estimate on the likelihood that each event is top, yields mt = 173.3 ± 5.6 (stat.) ± 6.2 (syst.) GeV/c2 . A combination of these two measurements gives mt = 173.1 ± 5.2 (stat.) ± 5.7 (syst.) GeV/c2
High-energy quark-quark scattering and the eikonal approximation
Meggiolaro, Enrico(Dipartimento di Fisica, Università di Pisa, and INFN, Sezione di Pisa, Largo Pontecorvo 3, I-56127, Pisa, Italy)
1997-01-01
The high-energy quark-quark scattering amplitude is calculated first in the case of scalar QCD, using Fradkin's approach to derive the scalar quark propagator in an external gluon field and computing it in the eikonal approximation. The results are then extended to the case of ``real'' (i.e., fermion) QCD. The high-energy quark-quark scattering amplitude turns out to be described by the expectation value of two lightlike Wilson lines, running along the classical trajectories of the two collid...