119949182
Systematic study for grey particles in relativistic nucleus + emulsion (Ag) interactions
The hadronic and string cascade model and the corresponding event generator LUCIAE are used to study systematically the production of the grey particles in (14.6, 60 and 200A GeV)0 + Em, (2004 GeV)Si + Em, (200A GeV)S + Em and (11.6A GeV)Au + Em reactions. The dependences of the mean multiplicity, the multiplicity distributions and the polar angular distributions of the grey particles on the incident energy, the projectile mass and the collision centrality observed in emulsion experiments, respectively, are all reproduced by LUCIAE calculations. In addition the effects of the rescattering on the grey particle production are also investigated.
124686282
A Rigidity Measurement of Pseudo-Rapidity Spectrum of Produced Particles in High Energy Nucleus-Nucleus Collisions
A new concept, rigidity of pseudo-rapidity spectrum, is extended into the study of the multiplicity fluctuations in high energy nucleus-nucleus interactions. In using the novel method to analyze the data of 16O-Em at 14.6, 60, and 200 A GeV, and 32S-Em at 200 A GeV, it is found that the rigidity of pseudo-rapidity spectrum in the central domain of pseudo-rapidity might be a mixture of Poisson type and Wigner one.
122178976
Fluctuations of K/π Ratios in Pb-Pb Collisions at Super Proton Synchrotron Energies
The Monte Carlo generator (LUCIAE) is used to investigate the fluctuations of K/π ratios at super proton synchrotron energies. The distribution of K/π ratios seems to be Gaussian from the simulation and the distribution width, and the relative variances are larger than those from the Poissonian-type pure-statistical fluctuations. This discrepancy might be attributed to the dynamical fluctuations involved in the LUCIAE model.
18595526
Enhancement of singly and multiply strangeness in p-Pb and Pb-Pb collisions at 158A GeV/c
The idea that the reduction of the strange quark suppression in string fragmentation leads to the enhancement of strange particle yield in nucleus-nucleus collisions is applied to study the singly and multiply strange particle production in p-Pb and Pb-Pb collisions at 158A GeV/c. In this mechanism the strange quark suppression factor is related to the effective string tension, which increases in turn with the increase of the energy, of the centrality and of the mass of colliding system. The WA97 observation that the strange particle enhancement increases with the increasing of centrality and of strange quark content in multiply strange particles in Pb-Pb collisions with respect to p-Pb collisions was accounted reasonably.
120471376
QGP phase transition and multiplicity fluctuations
The scaled factorial moments in QGP phase transitions are studied analytically by the extended Ginzburg-Landau model. The dependence of lnFq on phase space interval is different for the first- and second-order QGP phase transitions. When lnFq, are fitted to polynomials ofX≡δ1/3, the relative sign between the fitted coefficients ofX andbq,1 calculated theoretically can be used to judge the order of phase transitions. Two sets of experimental data are reanalysed and the phase transitions are the first order for one set of data but the second order for another.
119042314
CHARM PRODUCTION AT LARGE RAPIDITIES IN p+p AND d+Au COLLISIONS AT PHENIX AT RHIC
We study charm production through dimuon and single muon measurements at forward and backward rapidities in p+p and d+Au collisions with the PHENIX muon detectors. We also compare open charm to $J/\psi$ yields in the forward and backward rapidities in d+Au collisions and study the origin of the large forward and backward asymmetry in open charm production observed by the PHENIX experiment.
121472375
Mini-jets and multiplicity fluctuation in small rapidity intervals
Abstract The multiplicity fluctuation of particles in small rapidity intervals from mini-jets in high-energy hadron-hadron collisions are considered and a power-law behavior is found. An increase of the observed factorial moments with P T of the jets is expected. However, the fluctuation becomes smaller for larger total multiplicity due to the contributions from multiple mini-jets production.
124411042
Baryon Transport Dynamics: From P — P to PB — PB Collisions
Significant baryon stopping and strange hyperon production in heavy nuclear interactions has been recently observed at the CERN SPS [1,2,3,4,5]. The data is significantly under-predicted by models which use diquark-quark (qq − q) hadronic strings for their primary baryon number transport mechanism [6,7] and has thus generated much interest. We therefore study new baryon number transport mechanisms in order to differentiate non-equilibrium multi-particle production dynamics from any new sought after physics. We begin this study by reviewing two new mechanisms as implemented in the VENUS [8] and in a modified version of the dual parton model (DPM) [9] event generators. We then study a third new [10] mechanism, where the baryon number is specifically transferred via gluonic junctions. This mechanism has been implemented in the Monte Carlo event generator, HIJING/B[11], a new version of the HIJING model[12]. W e show that this gluonic mechanism can account for the observed large mid-rapidity valence baryon distribution at the SPS and predicts high baryon densities at RHIC. The highly enhanced hyperon yield and transverse momentum flow observed in PbPb collisions at the SPS can, however, only be partially reproduced by this model.
76655214
Hadron production in p+p, p+Pb, and Pb+Pb collisions with the HIJING 2.0 model at energies available at the CERN Large Hadron Collider
The Heavy-Ion Jet Interaction Generator (hijing) Monte Carlo model is updated with the latest parton distributions functions and a new set of the parameters in the two-component minijet model that controls the total p+p cross section and the central pseudorapity density. We study hadron spectra and multiplicity distributions using the hijing2.0 model and compare to recent experimental data from p+p collisions at the Large Hadron Collider (LHC) energies. We also give predictions of hadron production in p+p, p+Pb, and Pb+Pb collisions at the full LHC energy.
120386318
Gamma-jet tomography of high-energy nuclear collisions in NLO pQCD
Within the NLO pQCD partem model study, suppression of away‐side hadron spectra associated with a high pT photon due to parton energy loss is shown to provide more complete tomographic picture of the dense matter formed in high‐energy heavy‐ion collisions. Hadron spectra at large ZT = PTh/pTλ≳ 1 are more susceptible to parton energy loss and therefore are dominated by surface emission of λ‐correlated jets, whereas small ZT hadrons mainly come from fragmentation of jets with reduced energy which is controlled by the volume emission. These lead to different centrality dependence of the hadron suppression in different region of ZT.
119216214
Pair production of Higgs bosons associated with Z boson in the left–right twin Higgs model at the ILC
Abstract The left–right twin Higgs (LRTH) model predicts the existence of three additional Higgs bosons: one neutral Higgs ϕ 0 and a pair of charged Higgs bosons ϕ ± . In this paper, we studied the production of a pair of charged and neutral Higgs bosons associated with standard model gauge boson Z at the ILC, i.e., e + e − → Z ϕ + ϕ − and e + e − → Z ϕ 0 ϕ 0 . We calculate the production rate and present the distributions of the various observables, such as, the distributions of the energy and the transverse momenta of final Z-boson and charged Higgs boson ϕ − , the differential cross section of the invariant mass of charged Higgs bosons pair, the distribution of the angle between charged Higgs bosons pair and the production angle distributions of Z-boson and charged Higgs boson ϕ − . Our numerical results show that, for the process e + e − → Z ϕ + ϕ − , the production rates are at the level of 10 − 1 fb with reasonable parameter values. For the process of e + e − → Z ϕ 0 ϕ 0 , we find that the production cross section are smaller than 6 × 10 − 3 fb in most of parameter space. However, the resonance production cross section can be significantly enhanced.