vol. 35, p. 9 (7 pages)
•abstract
Recent pion HBT results from SPS are reviewed and compared to measurements at AGS and RHIC. The evaluation of the energy dependence leads to a universal freeze-out condition for pions. Implications of the HBT results on the dynamical evolution of heavy ion collisions are discussed.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/9/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/9
cite as
Acta Phys. Pol. B 35, 9 (2004)
vol. 35, p. 17 (6 pages)
•abstract
The first measurements of the pion source dimensions for Au–Au collisions at RHIC gave no direct evidence for a large or long-lived source, as previously expected for a deconfinement phase transition. This result has proved to be something of a puzzle when taken in context with indications of jet suppression for central Au–Au collisions. With the goal of illuminating what we do not know, we review aspects of our understanding of the two-particle correlation measurements that have recently yielded to relatively new analysis techniques, in 3-pion correlations, non-identical particle correlations, and self-consistent treatments of the Coulomb interaction.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/17/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/17
cite as
Acta Phys. Pol. B 35, 17 (2004)
vol. 35, p. 23 (6 pages)
•abstract
We review the recent developments on microscopic transport calculations for two-particle correlations at low relative momenta in ultrarelativistic heavy ion collisions at RHIC.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/23/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/23
cite as
Acta Phys. Pol. B 35, 23 (2004)
vol. 35, p. 29 (7 pages)
•abstract
The Wigner function formalism which relates source size parameters to experimental “HBT radii” extracted from two-particle Bose–Einstein correlations is generalized to azimuthally deformed and longitudinally tilted sources. It is explained how this can be used to complement anisotropic flow measurements with relevant space-time information on the source.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/29/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/29
cite as
Acta Phys. Pol. B 35, 29 (2004)
vol. 35, p. 37 (9 pages)
•abstract
Pion interferometry (“HBT”) measurements relative to the reaction plane provide an estimate of the transverse source anisotropy at freeze-out, which probes the system dynamics and evolution duration. Measurements by the STAR Collaboration indicate that the source is extended increasingly out-of-plane with increasing impact parameter, suggesting a short evolution duration, roughly consistent with estimates based on azimuthally-integrated HBT measurements.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/37/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/37
cite as
Acta Phys. Pol. B 35, 37 (2004)
vol. 35, p. 47 (7 pages)
•abstract
Non-identical particle correlations offer new methods of probing the dynamics of the heavy-ion collision. In STAR we have performed a correlation analysis of pion–kaon and pion–proton pairs for 130 \(A\)GeV AuAu collisions. The results show that average emission space-time points of these particle species are not the same. These asymmetries are interpreted as a consequence of space-momentum correlations produced by rapid transverse radial expansion of the system. The effects of emission time differences, coming from the decay of resonances, are also investigated with the help of rescattering models, and explain only part of the asymmetry. Therefore our measurements represent an independent confirmation of the existence of transverse radial flow.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/47/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/47
cite as
Acta Phys. Pol. B 35, 47 (2004)
vol. 35, p. 55 (7 pages)
•abstract
Both experimentalists and theorists dealing with Bose–Einstein correlations (BEC) in high energy interactions find themselves in an awkward situation. The observation of a very weak BEC signal between two hadronizing sources in the reaction \(e^+e^- \rightarrow W^+W^-\) could well indicate that our understanding of the BEC effect is quite poor. In this paper, an overview of the latest LEP results on BEC between particles from different \(W\)s is given. From the combination of these results, a systematic uncertainty on the measured \(W\) mass in the fully hadronic channel is estimated.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/55/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/55
cite as
Acta Phys. Pol. B 35, 55 (2004)
vol. 35, p. 63 (6 pages)
•abstract
Bose–Einstein correlations of identical charged pions are studied in deep inelastic \(ep\) scattering events measured with the ZEUS detector at HERA. In one-dimensional analysis the radius of the particle production source and the correlation strength are independent of the exchanged photon virtuality \(Q^2\) in the range between 0.1 and 8000 GeV\(^2\). No significant difference was found between the correlations measured in the target and current region of the Breit frame for \(Q^2\) \(\gt \) 100 GeV\(^2\). The result indicates insensitivity of the radius of the source to the underlying hard process. Two-dimensional analysis performed in the Longitudinally CoMoving System indicates an elongated shape of the source.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/63/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/63
cite as
Acta Phys. Pol. B 35, 63 (2004)
vol. 35, p. 69 (7 pages)
•abstract
Questions concerning the Bose–Einstein (BEC) and Fermi–Dirac (FDC) correlations of hadrons produced in \(e^+e^-\) collisions are discussed. Among them the emitter dimension \(r\) as a function of \(\sqrt {s_{ee}}\) and the hadron mass, the extension of the BEC by including isospin invariance and the proposed relation between \(r\) and the inter-atomic separation in Bose condensates.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/69/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/69
cite as
Acta Phys. Pol. B 35, 69 (2004)
vol. 35, p. 77 (7 pages)
•abstract
This talk serves as an introduction to the Heavy-Flavor session of the XXXIII International Symposium on Multiparticle Dynamics. A major focus of this session is on the production of heavy quarks. The talks which follow review the latest results on heavy quark production in strong, electromagnetic, and weak interactions, as well as some of the physics of the heavy quarks themselves. This talk emphasizes what we can learn from the production measurements, both about underlying QCD theory and the partonic nature of the hadrons which we see in the laboratory.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/77/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/77
cite as
Acta Phys. Pol. B 35, 77 (2004)
vol. 35, p. 85 (5 pages)
•abstract
Fixed-target experiments continue to provide insights into the physics of particle production in strong interactions. The experiments are performed with different types of beam particles of varying energies, and many different target materials. Studies of beauty and charm production are of particular interest, since experimental results can be compared to perturbative QCD calculations. It is in this context that recent results from fixed-target experiments on beauty and charm production will be reviewed.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/85/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/85
cite as
Acta Phys. Pol. B 35, 85 (2004)
vol. 35, p. 91 (5 pages)
•abstract
Precision measurements of charmonium spectroscopy are obtained studying charmonium formed in \(\overline {p}p\) annihilation. Two experiments at FNAL, E760 and E835, adopted this technique. Some of their results are briefly discussed.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/91/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/91
cite as
Acta Phys. Pol. B 35, 91 (2004)
vol. 35, p. 97 (4 pages)
•abstract
We present a new study of double \(c\bar {c}\) production in the \(e^+ e^-\) continuum: many double charmonium final states are observed for the first time; the \(e^+ e^- \to J/\psi c\bar {c}\) cross-section is measured with reduced model dependence.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/97/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/97
cite as
Acta Phys. Pol. B 35, 97 (2004)
vol. 35, p. 101 (6 pages)
•abstract
The production of b hadrons in \(e^+e^-\) interactions at the \(Z\) pole allows to perform detailed studies of their properties. Almost a million of \(Z^0\rightarrow {b}\bar {{b}}\) decays have been detected by the four LEP collaborations. In this contribution, some recent results on heavy flavour physics are presented.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/101/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/101
cite as
Acta Phys. Pol. B 35, 101 (2004)
vol. 35, p. 107 (7 pages)
•abstract
Measurements of open heavy flavour production in \(ep\) collisions at a center of mass energy of 318 GeV are reviewed in both photoproduction and deep inelastic scattering.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/107/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/107
cite as
Acta Phys. Pol. B 35, 107 (2004)
vol. 35, p. 115 (6 pages)
•abstract
Given the large number of heavy flavour results from the Tevatron this document can only be a subjective overview. The main selection criterion was to only present results obtained from the analysis of Tevatron Run II data. There is also a preference for cross section measurements, owing to the scope of the conference. The Tevatron and detector upgrades are only discussed briefly. All results are preliminary unless otherwise stated.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/115/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/115
cite as
Acta Phys. Pol. B 35, 115 (2004)
vol. 35, p. 121 (9 pages)
•abstract
Recent measurements of \(J/\psi \) production in \(e^+e^-\) colliders pose a challenge to the NRQCD factorization theorem for quarkonium production. Discrepancies between leading order calculations of color-octet contributions and the momentum distribution of \(J/\psi \) observed by Belle and BaBar are resolved by resumming large perturbative and nonperturbative corrections that are enhanced near the kinematic endpoint. The large cross sections for \(J/\psi c \bar c \) and double quarkonium production remain poorly understood. Nonperturbative effects in fixed-target hadroproduction of open charm are also discussed. Large asymmetries in the production of charm mesons and baryons probe nonperturbative corrections to the QCD factorization theorem. A power correction called heavy-quark recombination can economically explain these asymmetries with a few universal parameters.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/121/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/121
cite as
Acta Phys. Pol. B 35, 121 (2004)
vol. 35, p. 131 (7 pages)
•abstract
We discuss the effects of gluon radiation by the struck quark and the subsequent absorption of the produced hadron in deep inelastic lepton-nucleus scattering. The theoretical picture is compared with HERMES results on multiplicity ratios.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/131/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/131
cite as
Acta Phys. Pol. B 35, 131 (2004)
vol. 35, p. 139 (5 pages)
•abstract
The influence of the nuclear medium on the production of charged hadrons in semi-inclusive DIS has been studied by the HERMES experiment at DESY with a 27.5 GeV positron beam. The hadron multiplicity has been measured for helium, neon and krypton relative to that of deuterium. The multiplicity ratio is strongly reduced at high values of the atomic number \(A\). The \(A\)-dependence of HERMES data on krypton and nitrogen is discussed and is compared to two theoretical models. Assuming a simple \(A^\alpha \)-dependence of the nuclear attenuation, the HERMES data are found to be closer to the \(A^{2/3}\)-dependence predicted by some pQCD-based models than to the \(A^{1/3}\)-dependence that follows from models based on nuclear absorption only.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/139/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/139
cite as
Acta Phys. Pol. B 35, 139 (2004)
vol. 35, p. 145 (7 pages)
•abstract
Various phenomena observed in \(A+A\) collisions can be traced back to more elementary \(h+h\) and \(h+A\) reactions.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/145/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/145
cite as
Acta Phys. Pol. B 35, 145 (2004)
vol. 35, p. 153 (8 pages)
•abstract
In the framework of string percolation, the transverse momentum distributions in heavy ion collisions at all centralities and energies are shown to follow an universal behaviour, the shape of the distributions depending essentially on the transverse density of strings. We find that the relative suppression of intermediate and high \(p_{\rm T}\) production in central nucleus–nucleus collisions has the some origin as the narrowing of multiplicity distributions, the clustering of strings. The clustering of strings also explains naturally the dependence on the centrality of the transverse momentum fluctuations and the strength of the two and three body Bose–Einstein correlations.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/153/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/153
cite as
Acta Phys. Pol. B 35, 153 (2004)
vol. 35, p. 161 (7 pages)
•abstract
The inclusive distributions of gluons and pions for high-energy \(NN\) collisions are calculated. The results for several unintegrated gluon distributions (UGDs) from the literature are compared. We find huge differences in both rapidity and \(p_{\rm t}\) of gluons and \(\pi \)s in \(NN\) collisions for different models of UGDs. The Karzeev–Levin UGD gives good description of momentum distribution of charged hadrons at midrapidities. We find, however, that the gluonic mechanism discussed does not describe the inclusive spectra of charged particles in the fragmentation region. Some of the missing mechanisms are calculated with the help of unintegrated parton distributions from the solution of the CCFM equation.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/161/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/161
cite as
Acta Phys. Pol. B 35, 161 (2004)
vol. 35, p. 169 (9 pages)
•abstract
The status of thermodynamical approach in the multiple production processes and especially for very high multiplicity (VHM) domain is discussed. This approach is quite popular in the heavy ion collision physics. It is argued that the “principle of vanishing of correlations” must be used for quantitative estimations of the rate of thermalization. A review of present experimental information is offered.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/169/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/169
cite as
Acta Phys. Pol. B 35, 169 (2004)
all authors
Y. Hama, F. Grassi, O. Socolowski Jr., T. Kodama, M. Gaździcki, M.I. Gorenstein
vol. 35, p. 179 (4 pages)
•abstract
We calculate, in a hydrodynamic approach, the \(m_T\) spectra of kaons in central Pb+Pb (Au+Au) collisions, as function of energy. The experimentally observed anomalous behavior of the inverse slope parameter \(T^*\) may be reproduced by a reasonable choice of the critical temperature \(T_{\rm c}\sim 160\) MeV at \(\mu =0\) and an equally reasonable choice of energy-dependent freeze-out temperature \(T_{\rm fo}\), thus supporting the argument that these data are an additional signature of deconfinement transition.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/179/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/179
cite as
Acta Phys. Pol. B 35, 179 (2004)
vol. 35, p. 183 (4 pages)
•abstract
The \(\rho ^0(770)\), \(K^{*0}(892)\), \(f_{0}(980)\), \(\phi (1020)\), and \({\mit \Lambda }(1520)\) production in Au+Au and \(p\)+\(p\) collisions at \(\sqrt {s_{NN}}= 200\) GeV are presented. These resonances are used as a sensitive tool to examine the collision dynamics in the hadronic medium through their decay and regeneration. The modification of resonance mass, width, and shape due to phase space and dynamical effects are also discussed.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/183/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/183
cite as
Acta Phys. Pol. B 35, 183 (2004)
vol. 35, p. 187 (4 pages)
•abstract
The main results obtained within the energy scan program at the CERN SPS are presented. The anomalies in energy dependence of hadron production indicate that the onset of deconfinement phase transition is located at about 30 \(A\,\)GeV. For the first time we seem to have clear evidence for the existence of a deconfined state of matter in nature.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/187/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/187
cite as
Acta Phys. Pol. B 35, 187 (2004)
vol. 35, p. 191 (6 pages)
•abstract
We present simultaneous, quality fits to final BRAHMS, PHOBOS, STAR and PHENIX data on particle spectra and two-particle Bose–Einstein or HBT correlations as measured in Au+Au collisions at \(\sqrt {s_{NN}} = 130\) GeV. Using the Buda–Lund hydro model, the best fit is achieved when the most central 1/8th of the particle emitting volume is superheated to \(T \gt T_{\rm c} =170\) MeV. In contrast, we find no indication for such a hot central region in a similar analysis of Pb+Pb data at CERN SPS.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/191/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/191
cite as
Acta Phys. Pol. B 35, 191 (2004)
all authors
L. Šándor, F. Antinori, P.A. Bacon, A. Badalà, R. Barbera, A. Belogianni, A. Bhasin, I.J. Bloodworth, M. Bombara, G.E. Bruno, S.A. Bull, R. Caliandro, M. Campbell, W. Carena, N. Carrer, R.F. Clarke, A. Dainese, A.P. de Haas, P. de Rijke, D. Di Bari, S. Di Liberto, R. Divia, D. Elia, D. Evans, K. Fanebust, F. Fayazzadeh, G.A. Feofilov, R.A. Fini, P. Ganoti, B. Ghidini, G. Grella, H. Helstrup, M. Henriquez, A.K. Holme, A. Jacholkowski, G.T. Jones, P. Jovanovic, A. Jusko, R. Kamermans, J.B. Kinson, K. Knudson, A.A. Kolozhvari, V. Kondratiev, I. Králik, A. Kravčáková, P. Kuijer, V. Lenti, R. Lietava, G. Løvhøiden, V. Manzari, G. Martinská, M.A. Mazzoni, F. Meddi, A. Michalon, M. Morando, E. Nappi, F. Navach, P.I. Norman, A. Palmeri, G.S. Pappalardo, B. Pastirčák, J. Pišút, N. Pišútová, F. Posa, E. Quercigh, F. Riggi, D. Röhrich, G. Romano, K. Šafařík, E. Schillings, G. Segato, M. Sené, R. Sené, W. Snoeys, F. Soramel, M. Spyropoulou-Stassinaki, P. Staroba, T.A. Toulina, R. Turrisi, T.S. Tveter, J. Urbán, F.F. Valiev, A. van den Brink, P. van de Ven, P. Vande Vyvre, N. van Eijndhoven, J. van Hunen, A. Vascotto, T. Vik, O. Villalobos, L. Vinogradov, T. Virgili, M.F. Votruba, J. Vrláková, P. Závada
vol. 35, p. 197 (6 pages)
•abstract
Recent results on strange baryon and antibaryon production in Pb–Pb collisions at 160 GeV per nucleon from the NA57 experiment are reported. Strangeness enhancements and the transverse mass spectra properties are described.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/197/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/197
cite as
Acta Phys. Pol. B 35, 197 (2004)
vol. 35, p. 203 (4 pages)
•abstract
We discuss the \(\pi ^+ \pi ^-\) invariant-mass correlations and the resonance production in a thermal model with single freeze-out. The predictions are confronted with the recent data from the STAR Collaboration.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/203/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/203
cite as
Acta Phys. Pol. B 35, 203 (2004)
vol. 35, p. 207 (5 pages)
•abstract
We present a Monte Carlo calculation of the microcanonical ensemble of the of the ideal hadron-resonance gas including all known states up to a mass of 1.8 GeV, taking into account quantum statistics. The computing method is a development of a previous one based on a Metropolis Monte Carlo algorithm, with a the grand-canonical limit of the multi-species multiplicity distribution as proposal matrix. The microcanonical average multiplicities of the various hadron species are found to converge to the canonical ones for moderately low values of the total energy. This algorithm opens the way for event generators based for the statistical hadronization model.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/207/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/207
cite as
Acta Phys. Pol. B 35, 207 (2004)
vol. 35, p. 213 (9 pages)
•abstract
The idea of saturation of parton densities in small \(x\) physics is briefly introduced. Some aspects of saturation are described, mainly focusing on the status of our knowledge on the non-linear equations describing the high parton density regime. Implications of saturation ideas on the description of nuclear collisions at the Relativistic Heavy Ion Collider are discussed.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/213/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/213
cite as
Acta Phys. Pol. B 35, 213 (2004)
vol. 35, p. 223 (6 pages)
•abstract
Recent results on \(F_2\) and \(F_{\rm L}\) proton structure functions measurements in \(e^+p\) deep inelastic scattering (DIS) at low \(Q^2\) at HERA are presented.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/223/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/223
cite as
Acta Phys. Pol. B 35, 223 (2004)
vol. 35, p. 229 (6 pages)
•abstract
It is possible to study the low \(x\) behavior of the proton structure at HERA for \(x\) values as low as \(\sim 10^{-5}\). One of the most interesting aspects of low \(x\) proton structure is the study of QCD dynamics — the evolution of partons between kinematic regimes. In \(ep\) DIS, this can be studied inclusively by measuring the proton structure functions — \(F_2\), \(F_{\rm L}\), etc., or exclusively by studying processes in the target region of the proton — forward going jets and particles. In this paper, various measurements made at HERA by the H1 and ZEUS experiments are presented and compared to MC models and fixed-order QCD calculations. While DGLAP-based evolution is able to describe the inclusive, i.e. \(F_2\), data over the whole HERA kinematic region, a consistent picture of deviations from DGLAP models and fixed-order calculations in exclusive measurements is emerging. MC models and calculations based on BFKL or BFKL-like \(x\)-dependent parton evolution are able to describe most of the exclusive results.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/229/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/229
cite as
Acta Phys. Pol. B 35, 229 (2004)
vol. 35, p. 235 (5 pages)
•abstract
We review the basic phenomenological predictions of parton saturation models and evaluate their relevance in light of the data from Au + Au collisions at RHIC.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/235/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/235
cite as
Acta Phys. Pol. B 35, 235 (2004)
vol. 35, p. 241 (6 pages)
•abstract
The progress in the measurements of the photon and electron structure functions at LEP is discussed. The short introduction to the kinematics and theoretical framework of the structure functions measurements is given first. Then follow presentations of the recent measurements of the hadronic structure function of the photon, and in particular the charm structure function, which have been updated by using the full LEP2 statistics. The first measurement of the electron structure function is also presented.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/241/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/241
cite as
Acta Phys. Pol. B 35, 241 (2004)
vol. 35, p. 247 (9 pages)
•abstract
Recent developments of the small \(x\) CCFM evolution are described, including improvements of the splitting function. The resulting unintegrated gluon densities are used for predictions of hadronic final state measurements like jet production at HERA and heavy quark production at the Tevatron.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/247/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/247
cite as
Acta Phys. Pol. B 35, 247 (2004)
vol. 35, p. 257 (4 pages)
•abstract
The LDC formalism for DIS can describe HERA structure functions, and also agrees well with CTEQ and MRST gluon distributions. It is also suitable for hadronic collisions, and provides a strong connection between \(ep\) and \(pp\) reactions. Some preliminary results are presented.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/257/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/257
cite as
Acta Phys. Pol. B 35, 257 (2004)
vol. 35, p. 261 (4 pages)
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/261/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/261
cite as
Acta Phys. Pol. B 35, 261 (2004)
vol. 35, p. 265 (7 pages)
•abstract
At low \(x\) a transition from a dilute parton gas to a dense parton liquid takes place. We derive geometrical scaling for the structure function in deep inelastic scattering at low \(x\) from a diverging correlation length \(\xi (x)\) of Wilson lines near the light cone. QCD (SU(3)) in \(2+1\) space–time dimensions near the light cone becomes a critical theory in the limit of \(x \rightarrow 0\) with a diverging correlation length \(\xi (x) \propto x^{-{1/2 \lambda _2}}\) where the exponent \(\lambda _2=2.52\) is obtained from the center group Z(3) of SU(3).
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/265/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/265
cite as
Acta Phys. Pol. B 35, 265 (2004)
vol. 35, p. 273 (9 pages)
•abstract
An overview of the physics of event by event fluctuations in heavy ion collisions is provided. Several observables are discussed.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/273/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/273
cite as
Acta Phys. Pol. B 35, 273 (2004)
vol. 35, p. 283 (6 pages)
•abstract
To describe large momentum distributions of charged hadrons observed at RHIC, a diffusion equation in the three dimensional hyperbolic space is introduced.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/283/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/283
cite as
Acta Phys. Pol. B 35, 283 (2004)
vol. 35, p. 289 (6 pages)
•abstract
It reports on charge fluctuations in \(\pi ^{+}p\) and \(K^{+}p\) collisions at 250 GeV/\(c\). The dependence of these fluctuations on the size of rapidity window and on the multiplicity are presented systematically. The results are compared with those obtained from current theoretical expectations for a hadronic gas, a QGP phase, a stochastic model and a PYTHIA simulation.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/289/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/289
cite as
Acta Phys. Pol. B 35, 289 (2004)
vol. 35, p. 295 (8 pages)
•abstract
Collective behavior of secondary particles in \(pp\)-interactions at 70 GeV/\(c\) is studied. A Two Stage Gluon Model is offered to describe processes with very high multiplicity. An active role of gluons is shown in multiparticle dynamics. The analysis of multiplicity distributions has revealed a possibility of a thermodynamic interpretation of these interactions. A mechanism of the soft photon production as a signature of the quark–gluon system is proposed.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/295/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/295
cite as
Acta Phys. Pol. B 35, 295 (2004)
vol. 35, p. 303 (5 pages)
•abstract
The dual parton model event generator Dpmjet-III is compared to some selected data from the RHIC collider. The aim is to find out, which features of the two-component dual parton model have to be modified in such collisions.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/303/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/303
cite as
Acta Phys. Pol. B 35, 303 (2004)
vol. 35, p. 309 (6 pages)
•abstract
The properties of a new possible class of events, characterised by large hadronic densities and very few clans, in proton-proton collisions at LHC energy are explored within the mechanism of the weighted superposition of different substructures. The most surprising feature is the appearance of an “elbow structure” in the high multiplicity tail, leading to very large expected multiplicity fluctuations.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/309/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/309
cite as
Acta Phys. Pol. B 35, 309 (2004)
vol. 35, p. 315 (6 pages)
•abstract
We argue that data coming from the Japanese–American cooperative emulsion experiment (JACEE) on the Si + AgBr event at 4 TeV/nucleon reveal a remarkable regularity (without adjusting any free parameter) which is in accord with the quantum statistical expectation.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/315/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/315
cite as
Acta Phys. Pol. B 35, 315 (2004)
vol. 35, p. 321 (10 pages)
•abstract
Cosmic ray showers offer a mean to study flux, particle type and arrival direction of primary cosmic rays at high energy. Such showers are formed by successive and competing particle interaction and decay processes. Detailed understanding of hadronic and electromagnetic particle production processes is needed to link the observed shower characteristics to properties of the primary particle. In this contribution we discuss some aspects of hadronic interaction models used in extensive air shower simulation and the importance and complementary nature of accelerator and cosmic ray measurements for improving these models.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/321/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/321
cite as
Acta Phys. Pol. B 35, 321 (2004)
all authors
A. Haungs, T. Antoni, W.D. Apel, F. Badea, K. Bekk, A. Bercuci, H. Blümer, H. Bozdog, I.M. Brancus, C. Büttner, A. Chilingarian, K. Daumiller, P. Doll, R. Engel, J. Engler, F. Feßler, H.J. Gils, R. Glasstetter, D. Heck, J.R. Hörandel, K.-H. Kampert, H.O. Klages, G. Maier, H.J. Mathes, H.J. Mayer, J. Milke, M. Müller, R. Obenland, J. Oehlschläger, S. Ostapchenko, M. Petcu, S. Plewnia, H. Rebel, A. Risse, M. Risse, M. Roth, G. Schatz, H. Schieler, J. Scholz, T. Thouw, H. Ulrich, J. van Buren, A. Vardanyan, A. Weindl, J. Wochele, J. Zabierowski, S. Zagromski
vol. 35, p. 331 (9 pages)
•abstract
A brief review is given on the astrophysics of cosmic rays in the PeV primary energy range, i.e. the region of the knee.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/331/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/331
cite as
Acta Phys. Pol. B 35, 331 (2004)
all authors
J. Milke, T. Antoni, W.D. Apel, A.F. Badea, K. Bekk, A. Bercuci, H. Blümer, H. Bozdog, I.M. Brancus, C. Büttner, A. Chilingarian, K. Daumiller, P. Doll, R. Engel, J. Engler, F. Feßler, H.J. Gils, R. Glasstetter, A. Haungs, D. Heck, J.R. Hörandel, K.-H. Kampert, H.O. Klages, G. Maier, H.J. Mathes, H.J. Mayer, M. Müller, R. Obenland, J. Oehlschläger, S. Ostapchenko, M. Petcu, S. Plewnia, H. Rebel, A. Risse, M. Risse, M. Roth, G. Schatz, H. Schieler, J. Scholz, T. Thouw, H. Ulrich, J. van Buren, A. Vardanyan, A. Weindl, J. Wochele, J. Zabierowski, S. Zagromski
vol. 35, p. 341 (9 pages)
•abstract
The interpretation of extensive air shower (EAS) measurements depends on the comparison with EAS simulations. These calculations rely on hadronic interaction models which have to extrapolate into kinematical and energy regions not covered by present-day collider experiments. Therefore, it is necessary to check the reliability of the interaction models used. For the EAS simulations the program CORSIKA is used with several hadronic event generators embedded. Different observables, measured with the KASCADE experiment simultaneously for each air shower event, are investigated as well as their correlations. The consistency of the models applied is checked by comparison of experimental and simulated results.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/341/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/341
cite as
Acta Phys. Pol. B 35, 341 (2004)
vol. 35, p. 351 (14 pages)
•abstract
Observations of cosmic rays with energies above \(\sim 4\times 10^{10}\) GeV have inspired several speculative suggestions concerning their origin. The crucial question is whether or not the spectrum exhibits the expected ‘GZK cutoff’ at this energy — concerning which there are presently contradictory results. If there is indeed a cutoff, then the sources are cosmologically distant and rather exotic in nature. If there is no cutoff then new physics is required.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/351/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/351
cite as
Acta Phys. Pol. B 35, 351 (2004)
vol. 35, p. 365 (11 pages)
•abstract
I present some recent experimental results in jet physics. The general themes are color reconnection, rapidity gaps, particle multiplicities in jets, and differences between gluon and quark jets. Data from \(e^+e^-\), \( p\overline { p}\) and \(ep\) collisions are presented.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/365/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/365
cite as
Acta Phys. Pol. B 35, 365 (2004)
vol. 35, p. 377 (10 pages)
•abstract
Some of the most recent results on jet production at HERA are reviewed. The measurements are confronted with predictions from next-to-leading order Quantum Chromodynamics. In regions where uncertainties are small, the strong coupling, \(\alpha _{\rm s}\), has been extracted. Other topics of current interest are also highlighted.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/377/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/377
cite as
Acta Phys. Pol. B 35, 377 (2004)
vol. 35, p. 387 (6 pages)
•abstract
Several preliminary QCD results from \(e^+e^-\) interactions at LEP are reported. These include studies of event shape variables, which are used to determine \(\alpha _{\mathrm s}\) and for studies of the validity of power corrections. Further, a study of color reconnection effects in 3-jet \(Z\) decays is reported.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/387/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/387
cite as
Acta Phys. Pol. B 35, 387 (2004)
vol. 35, p. 393 (7 pages)
•abstract
Recent QCD result obtained from the Tevatron Run II data are reported. The CDF and DØ experiments at the Tevatron has used \(p\bar {p}\) collisions at \(\sqrt {s} = 1.96 \textrm { TeV}\) to measure the inclusive jet and dijet mass spectra.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/393/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/393
cite as
Acta Phys. Pol. B 35, 393 (2004)
vol. 35, p. 401 (5 pages)
•abstract
Presented are results from the recent jet fragmentation and underlying event structure studies carried out by the CDF Collaboration. Multiplicities of charged particles in quark and gluon jets are measured and their ratio is compared to pQCD predictions. The results are compared to the earlier measurements obtained at \(e^+ e^-\) colliders. Average charged particle multiplicities and energy flow in the underlying event are compared to PYTHIA Monte Carlo event generator; the necessary tuning of PYTHIA parameters needed to make it match the data is discussed.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/401/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/401
cite as
Acta Phys. Pol. B 35, 401 (2004)
vol. 35, p. 407 (4 pages)
•abstract
We present the first experimental results based on the jet boost algorithm, a technique to define unbiased gluon jet samples in \(e^+e^-\) annihilations, i.e. events free of any bias from event selection or jet finding criteria. The boost algorithm has been tested using the Herwig Monte Carlo event generator and then applied to hadronic \(Z^0\) decays observed with the OPAL detector at the LEP collider. The gluon jet charged particle multiplicity distribution has been measured in seven jet energy bins from 5 to 20 GeV. From these distributions, the mean value and the first two non trivial normalized factorial moments have been extracted. The gluon jet fragmentation function has been measured in two jet energy bins between 14 and 20 GeV. The results have been compared with existing QCD predictions. In general, good agreement has been found between theory data.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/407/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/407
cite as
Acta Phys. Pol. B 35, 407 (2004)
vol. 35, p. 411 (5 pages)
•abstract
We build a computer code that fully automates the resummation of jet-observable distributions at next-to-leading logarithmic accuracy. As an application we present results for a jet shape in hadronic dijet production.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/411/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/411
cite as
Acta Phys. Pol. B 35, 411 (2004)
vol. 35, p. 417 (12 pages)
•abstract
The perturbative quantum chromodynamics (pQCD) has been extremely successful in the prediction and description of main properties of quark and gluon jets. There are, however, some problems of the jet calculus with the higher order corrections of the modified perturbative expansion which should be resolved to get more precise statements. Some of them are discussed here.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/417/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/417
cite as
Acta Phys. Pol. B 35, 417 (2004)
vol. 35, p. 429 (4 pages)
•abstract
Recently, the moments of multiplicity distributions in \(e^+e^-\) annihilation and the ratios \(H_q\) (cumulant over factorial moments \(K_q~/~F_q\)) have been determined both for the hadronic final state and for jets at variable resolution. These ratios show an oscillatory behaviour as function of \(q\) with strong dependence of the amplitude and length of oscillation on the jet resolution parameter \(y_{\rm cut}\). The recent explanation of this phenomenon based on perturbative QCD calculations is discussed.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/429/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/429
cite as
Acta Phys. Pol. B 35, 429 (2004)
vol. 35, p. 433 (9 pages)
•abstract
Minimum bias and underlying event data from the \(Sp\bar {{p}}S\) and the Tevatron have been compared to PYTHIA and PHOJET simulations. The data have been used to tune the PYTHIA multiparton model and good agreement is found. PHOJET also gives good agreement. Predictions are made for the multiplicities in minimum bias and the underlying events at the LHC. PYTHIA predicts increases by factors of order two to three from Tevatron energies, while PHOJET predicts more modest increases by a factor of 1.5. The effect of different levels of underlying event activity on the central jet veto used in Higgs searches in the vector boson fusion channel is investigated.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/433/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/433
cite as
Acta Phys. Pol. B 35, 433 (2004)
vol. 35, p. 443 (4 pages)
•abstract
We study non-perturbative evolution of the gluon states during small time. Fluctuations of the gluons are less than those for coherent states that is indication of the gluon squeezed states. We show that the two-mode squeezed and entangled states of the gluon fields can appear as a result of the non-perturbative gluon selfinteraction.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/443/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/443
cite as
Acta Phys. Pol. B 35, 443 (2004)
vol. 35, p. 447 (18 pages)
•abstract
Studies of diffractive events performed by the H1 and ZEUS Collaborations at the HERA \(ep\) collider are presented. The data of vector meson and photon production, inclusive deep inelastic scattering and hadronic final states with open charm and jets are confronted with the predictions of the resolved Pomeron and colour dipole models.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/447/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/447
cite as
Acta Phys. Pol. B 35, 447 (2004)
vol. 35, p. 465 (7 pages)
•abstract
Forward detectors are described together with the first physics results from Run II. Using new data and dedicated diffractive triggers, a measurement of single diffractive dijet production rate, with particular focus on the diffractive structure function of the antiproton, is discussed. Upper limits on the exclusive dijet and \(\chi ^0_c\) production cross sections are also presented.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/465/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/465
cite as
Acta Phys. Pol. B 35, 465 (2004)
vol. 35, p. 473 (9 pages)
•abstract
Dissociation of virtual photons, \({\gamma }^* p \rightarrow Xp\), has been studied in \(ep\) interactions with the ZEUS detector at HERA. The diffractive cross section, \(d\sigma _{\gamma ^*p}~/~dM_X\), is presented as a function of the photon virtuality, \(Q^2\). The \(W\) dependence of the diffractive and the total cross section is compared. The dependence of the diffractive structure function, \(F_2^{D(3)}\), on \(\beta \), the Pomeron momentum fraction probed by photon, is also studied. The data are compared to predictions based on dipole models.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/473/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/473
cite as
Acta Phys. Pol. B 35, 473 (2004)
vol. 35, p. 483 (5 pages)
•abstract
The double diffractive photoproduction of \(J/\psi \) mesons, \(\gamma p \rightarrow J/\psi \) \(Y\), has been studied in \(ep\) collisions with the ZEUS and H1 detectors at HERA. The differential cross section \(d\sigma /dt\), where \(t\) is the four-momentum transfer squared at the proton vertex, has been measured for \(|t|\lt 30\) \({\rm GeV^2}\). The total cross section has been presented as a function of the photon-proton centre-of-mass energy, \(W_{\gamma p}\), in the kinematic range \(50\lt W_{\gamma p}\lt 245\) \({\rm GeV}\). The results are compared with perturbative QCD models based on BFKL and DGLAP evolution.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/483/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/483
cite as
Acta Phys. Pol. B 35, 483 (2004)
vol. 35, p. 489 (7 pages)
•abstract
We present preliminary results on the diffractive charmonium production at the HERA-B experiment. An excess of the events with a large rapidity gap between \(J/\psi \) and the outgoing proton system is observed, while a much smaller excess of that between \(J/\psi \) and the outgoing nucleus system is found. The \(A\)-dependence for the events with the large rapidity gap is measured. The search for the Double Pomeron Exchange charmonium production results in the upper limits on the proton–carbon cross-section times the radiative branching fraction of \(\sigma _{\chi _{c0}}^{\rm DPE} \times {\rm BR\,} \lt 0.5\)nb and \(\sigma _{\chi _{c1,2}}^{\rm DPE} \times {\rm BR\,} \lt 1.1\)nb at 90% C.L. The upper limits cover part of the region of the theoretical expectations.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/489/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/489
cite as
Acta Phys. Pol. B 35, 489 (2004)
vol. 35, p. 497 (6 pages)
•abstract
We review QCD based descriptions of diffractive deep inelastic scattering emphasizing the role of models with parton saturation. These models provide natural explanation of such experimentally observed facts as the constant ratio of \(\sigma ^{\rm diff}/\sigma ^{\rm tot}\) as a function of the Bjorken variable \(x\) and Regge factorization of diffractive parton distributions.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/497/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/497
cite as
Acta Phys. Pol. B 35, 497 (2004)
vol. 35, p. 503 (8 pages)
•abstract
In this summary I briefly discuss some of the many interesting talks presented at this symposium.
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/35/1/503/pdf
link to the articles list
https://www.actaphys.uj.edu.pl/R/35/1/503
cite as
Acta Phys. Pol. B 35, 503 (2004)
▲ top
PL ISSN 0587-4254 • APPB printed version
PL ISSN 1509-5770 • APPB electronic version
PL ISSN 1899-2358 • APPB Proc. Suppl. printed version
PL ISSN 2082-7865 • APPB Proc. Suppl. electronic version
Acta Physica Polonica B
Faculty of Physics, Astronomy and Applied Computer Science
S. Łojasiewicza 11, 30-348 Kraków, Poland
phone: (+48) 12 664 49 68 • (+48) 12 664 46 46
e-mail: acta.phys.pol.b@uj.edu.pl