122934588
Multi-component Erlang distribution of final-state particles produced in high energy collisions
A unified formula on multiplicity distributions of final-state particles is studied in this paper to describe a variety of experimental data including multiplicity, mass, transverse mass, excitation energy, transverse energy, and transverse momentum distributions. It is assumed that the sources of final-state particles are subjected to the multi-source thermal model and the contributions of sources meet the Erlang distribution. Further the validity of the unified formula in descriptions of different distributions is tested. Experimental data of proton-antiproton $$(p\overline{p}),$$ positron–proton (e+p), electron-proton (e−p), and nucleus-nucleus (AA) collisions are analyzed and found that the distributions of mentioned quantities can be described by the multi-component Erlang distribution.
121546377
Dependences of charged particle pseudorapidity distributions on impact parameter and center-of-mass energy in nucleus–nucleus collisions at relativistic energies
The centrality and rapidity dependence of charged particles over a wide range of center-of-mass energy are analyzed. In this framework of participant-spectator model, the interacting system of nucleus–nucleus collisions at relativistic energies is divided into four parts (sources): target spectator, target participant, projectile participant and projectile spectator. Each source is treated by using a revised Landau model. The pseudorapidity distributions calculated by four-component Landau model are found to be in agreement with experimental data of the PHOBOS and ALICE collaborations. The distribution height is mainly determined by effective nucleon number and center-of-mass energy; and the distribution width being measured by the revised width in the Landau model and the sources rapidity shifts. Furthermore, we have found two empirical relations for projectile-participant and projectile-spectator (pseudo)rapidity as functions of the center-of-mass energy.
120288217
Comparing two-Boltzmann distribution and Tsallis statistics of particle transverse momentums in collisions at LHC energies
The transverse momentum distributions of final-state particles produced in collisions at energies available at the Large Hadron Collider (LHC) are studied by using the two-Boltzmann distribution and Tsallis statistics. Experimental distributions described by the two-Boltzmann distribution can be described by the Tsallis statistics. The two-temperature emission described by the two-Boltzmann distribution reflects temperature fluctuation of interacting system. The Tsallis statistics can describe the temperature fluctuation and the degree of non-equilibrium. The results calculated by the two-Boltzmann distribution and the Tsallis statistics are in agreement with the experimental data available at the LHC energies. In some cases, the two-Boltzmann distribution degenerates to (single) Boltzmann distribution.
124273608
Strange Quark Matter and Strangelets in a Strong Magnetic Field
We study the stability properties of magnetized strange quark matter and strangelets under a strong magnetic field in the MIT bag model. The free energy per baryon of strange quark matter feels a great influence from the magnetic held. At the held strength about 1017 G, the magnetized strange quark matter becomes more stable. Considering the finite size effect, the magnetic influence on strangelets becomes complicated. For a given magnetic held, there exists a critical baryon number, below which the magnetized strangelets have lower energy than the non-magnetized strangelets. For the held strength of 5 × 1017 G, the critical baryon number is Ac ~ 100. Generally, the critical baryon number increases with the decreasing external magnetic held. When the held strength is smaller than 1017 G, the critical baryon number goes up to Ac ~ 105. The stable radius, electric charge, and quark flavor fractions of magnetized strangelets are shown.
55102165
On Current Conversion between Particle Rapidity and Pseudorapidity Distributions in High Energy Collisions
In high energy collisions, one usually needs to give a conversion between the particle rapidity and pseudorapidity distributions. Currently, two equivalent conversion formulas are used in experimental and theoretical analyses. An investigation in the present work shows that the two conversions are incomplete. Then, we give a revision on the current conversion between the particle rapidity and pseudorapidity distributions.
122616125
Transverse momentum distribution of particles in high energy collisions and relativistic temperature transformation
Based on kinetic theory of ideal gas, the present work gives an indirect measurement on relativistic temperature transformation by using transverse momentum distribution of particles. Our result shows that Planck–Einstein relation is right. A moving system which has no energy current exchange with external surroundings becomes cool.
121033558
Dependence of shower particle pseudorapidity and pseudorapidity gap distributions on multiplicity in high-energy neutrino-emulsion collisions
The pseudorapidity and pseudorapidity gap distributions of shower particles in different event groups selected by multiplicity in 3\char21{}210 GeV neutrino-emulsion collisions are reported and analyzed by the thermalized cylinder model. It is shown that the pseudorapidity distribution has a slight dependence on the multiplicity and the pseudorapidity gap distribution does not depend on the multiplicity. The calculated results by the thermalized cylinder model are compared and found to be in agreement with the experimental data.
118242080
Multiplicity and Transverse Energy Distributions in Au-Au and Pb-Pb Collisions
The multiplicity and transverse energy distributions in high-energy nucleus-nucleus collisions are described by a geometrical model, namely the participant-spectator model. The calculated results are compared and found to be in agreement with the experimental data on Au-Au collisions at the RHIC energy and Pb-Pb collisions at the SPS energy.
117754834
Emission of Relativistic Light Fragments in Nucleus-Emulsion Collisions at High Energy
The transverse momentum, emission angle and pseudorapidity distributions of relativistic ® fragments produced in nucleus-emulsion collisions have been analysed using a two-temperature emission picture. The two emission sources are the projectile spectator contact layer (hot spectator) with high temperature and the other part (cold spectator) with low temperature. The transverse momentum distributions of relativistic proton fragments produced in nucleus-emulsion collisions at high energy have been analysed by a three-temperature emission picture. The three emission sources are the projectile participant local region that emits the leading protons, the projectile spectator contact layer (hot spectator) and the other part (cold spectator), respectively. The calculated results are in agreement with the experimental data of nucleus-emulsion collisions in the present accelerator energy region. The temperatures of the emission sources can be obtained from one of the transverse momentum, emission angle and pseudorapidity distributions. For a heavy projectile at high energy (for example 208Pb at 160A GeV), the temperatures of the hot spectator and the cold spectator obtained from the pseudorapidity distribution of relativistic ® fragments are 120 and 40 MeV, respectively.
123174567
Conditional moments in nuclear fragmentation and liquid-gas phase transition in hot nuclei
The conditional moments of the charge distributions of the projectile fragments in sulphur fragmentation at 200 GeV/N are obtained using the simple Monte Carlo partition method. Thus, the logarithmic correlations between the conditional moments can be observed. The distributions of conditional moments are investigated. The results of the nuclear diffractive excitation, electromagnetic dissociation, and Monte Carlo methods are compared.
122895317
Dependence of charged particle pseudorapidity distributions on centrality and energy in p(d)A collisions at high energies
The pseudorapidity distributions of charged particles produced in deuteron-gold (d-Au) and proton-emulsion (p-Em) collisions at high energies are studied in the framework of the two-cylinder model. The experimental results of nuclear reactions induced by protons and deuterons [p(d)A collisions] can be simply described by this model. The dependencies of parameter values on centrality for d-Au collisions and on nucleon-nucleon center-of-mass energy for p-Em collisions are obtained. The formula obtained by this model is a unified formula in the description of (pseudo)rapidity distributions of final-state particles produced in different interactions over an energy range from intermediate accelerator energy to ultrahigh cosmic-ray energy.