The centrality dependence of transverse momentum spectra for identified hadrons at midrapidity in Au+Au collisions at $\sqrt{s_{NN}}= 200$ GeV is systematically studied in a quark combination model. The $\mathrm{{p}_{T}}$ spectra of $π^{\pm}$, $K^{\pm}$, $p(\bar{p})$ and $Λ(\barΛ)$ in different centrality bins and the nuclear modification factors ($R_{CP}$) for these hadrons are calculated. The centrality dependence of the average collective transverse velocity $<β(r)>$ for the hot and dense quark matter is obtained in Au+Au collisions, and it is applied to a relative smaller Cu+Cu collision system. The centrality dependence of $\mathrm{{p}_{T}}$ spectra and the $R_{CP}$ for $π^{0}$, $K_{s}^{0}$ and $Λ$ in Cu+Cu collisions at $\sqrt{s_{NN}}= 200$ GeV are well described. The results show that $<β(r)>$ is only a function of the number of participants $N_{part}$ and it is independent of the collision system.
We analyse the centrality dependence of thermal parameters deduced from hadron m ultiplicities in Au + Au collisions at $\sqrt{s_{NN}} = 130 GeV$. While the chemical freeze-out temperature and chemical potentials are found to be roughly centrality-independent, the strangeness saturation factor $γ_S$ increases with participant number towards unity, supporting the assumption of equilibrium freeze-out conditions in central collisions.
Slow nucleons emitted during a hadron-nucleus interaction can give information on the centrality, impact parameter of the collision. The aim of this note is to provide the reader with the important characteristics of the slow nucleons, focusing on their spectra, correlations. This study tries to build on evidences, hence more weight is put on experimental results than on models.
In hadron interactions at the LHC energies, the reflective scattering mode starts to play a role which is expected to be even a more significant beyond the energies of the LHC. This new but still arguable phenomenon implies a peripheral dependence of the inelastic probability distribution in the impact parameter space and asymptotically evolving to the black ring. As a consequence, the straightforward extension to hadrons of the centrality definition adopted for nuclei needs to be modified.
We analyze the centrality dependence of thermal parameters describing hadron multiplicities, hadron spectra and dilepton spectra in heavy-ion collisions at SPS and RHIC energies.
The centrality dependence of thermal parameters describing hadron multiplicities and intermediate-mass dilepton spectra in heavy-ion collisions at SPS and RHIC is analyzed. From experimental hadron multiplicities we deduce evidence for strangeness saturation at high energy and maximum centrality. The observed dilepton spectra can be parameterized by a centrality independent temperature.
We apply an equal-velocity quark combination model to systematically study the transverse momentum (p_{T}) spectra of strange hadrons K_{S}^{0}, ϕ, Λ, Ξ^{-}, Ω^{-}, \barΛ, \barΞ^{+} and \barΩ^{+} at mid-rapidity in Au+Au collisions at \sqrt{s_{NN}}= 7.7, 11.5, 19.6, 27, 39, 54.4 GeV. Relative deviation between the model calculation and experimental data of these eight hadrons is generally about 2-3% at \sqrt{s_{NN}}= 27, 39, 54.4 GeV and in central collisions at 7.7, 11.5, 19.6 GeV. The deviation slightly increases up to about 4% in the semi-central and peripheral collision at \sqrt{s_{NN}}= 7…
The reflective scattering mode is supposed to play a significant role in hadron interactions at the LHC energy region and beyond. We discuss connection of this mode to the color conducting medium formation in hadron collisions and its role in centrality determination. The issues of centrality in view of the measurements at the LHC are relevant for enlightening the asymptotic dynamics.
We describe the transverse momentum spectra of $π^\pm$, $K^\pm$, $p$, and $\bar{p}$ produced in different centralities gold-gold (Au-Au) collisions at different collision energies range from 7.7 to 62.4 GeV by a two-component Erlang distribution. The fitting results are consistent with the experimental data, and the centrality- and energy-dependent yield ratios of negative to positive particles are obtained from the normalization constants. Based on the yield ratios, the energy- and centrality-dependent chemical potentials of light hadrons and quarks are extracted. The study shows that the dep…
Transverse momentum distributions of deuterons and anti-deuterons in Au+Au collisions at $\sqrt{S_{NN}}$=14.5, 62.4 and 200 GeV with different centrality are studied in the framework of the multisource thermal model. Transverse momentum spectra are conformably and approximately described by the Tsallis distribution. The dependence of parameters (average transverse momenta, effective temperature and entropy index) on event centrality are obtained. It is found that the parameters increase with increase of the average number of particles involved in collisions, which reveals the nuclear stopping …
Centrality-dependent measurements of hadron and jet cross section attenuation in deep inelastic scattering on nuclei can shed new light on the physics of final-state interactions in the nuclear matter, including the path-length dependence of the in-medium parton shower formation and evolution. Recent simulation studies have demonstrated the feasibility of experimental centrality determination in $e$A reactions at the electron-ion collider via neutron detection in the zero-degree calorimeter. Motivated by these results, we present the first theoretical calculation of the production rate modific…
We attempt to describe the rapidity distribution of P, P-bar, K+ and K- for the most central Au+Au collisions at root(sNN) of 62.4 GeV,130 GeV and 200 GeV. The transverse momentum spectra of strange as well as non-strange hadrons e.g. P, P-bar, K+, K-, Lambda, Lambda-bar, Cascade,Cascade-bar and (Omega + Omega-bar) are studied for the whole centrality classes at all the three RHIC energies. The experimental data of the transverse momentum spectra and the rapidity distributions are well reproduced. This is done by using a statistical thermal freeze-out model which incorporates the rapidity (col…
In Israel-Stewart's theory of dissipative hydrodynamics, we have analyzed the recent ALICE data for the centrality dependence of charged particle multiplicity, centrality dependence of integrated elliptic flow and 0-5% charged particles $p_T$ spectra in $\sqrt{s}_{NN}$=2.76 TeV Pb+Pb collisions and determined the initial or the thermalisation time. Analysis indicate that the ALICE data disfavor very early thermalsiation $τ_i$=0.2 fm, or very late thermalsation $τ_i$= 4fm. Data are best explained for thermalisation time $τ_i=0.88^{-0.14}_{+0.68}$ fm.
We present an analysis of hadronic multiplicities measured in Pb-Pb collisions at \sqrt s_{NN} = 2.76 TeV as a function of the collision centrality within the statistical hadronization model. Evidence is found of a dependence of the chemical freeze-out temperature as a function of centrality, with a slow rise from central to peripheral collisions, which we interpret as an effect of post-hadronization inelastic scatterings. Using correction factors calculated by means of a simulation based on the UrQMD model, we are able to obtain a significant improvement in the statitical model fit quality an…
A two-component analysis of spectra to $p_t = 12$ GeV/c for identified pions and protons from 200 GeV Au-Au collisions is presented. The method is similar to an analysis of the $n_{ch}$ dependence of $p_t$ spectra from p-p collisions at 200 GeV, but applied to Au-Au centrality dependence. The soft-component reference is a Lévy distribution on transverse mass $m_t$. The hard-component reference is a Gaussian on $y_t$ with exponential ($p_t$ power-law) tail. Deviations of data from the reference are described by hard-component ratio $r_{AA}$ which generalizes nuclear modification factor $R_{AA}$…
A recent study of 5 TeV $p$-Pb centrality combined a Glauber model of $p$-Pb collision geometry with an assumption of linear scaling between $n_{ch}$ (charge) integrated within some $η$ acceptance and the number of nucleon participants $N_{part}$. The study concluded that $N_{part}$ increases to nearly 16 in central collisions, and the high-$p_t$ region of $p$-Pb $p_t$ spectra rescaled by the Glauber-estimated number of $p$-N binary collisions remains consistent with a $p$-$p$ spectrum for the same energy, independent of $p$-Pb centrality. However, the relation between $N_{part}$ and $n_{ch}$ …
In this paper we have shown theoretical model comparisons with ALICE results for average D mesons (D$^0$, D$^+$, D$^{*+}$ and $D^+_s$) in $p$+Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV for various centralities. Transport calculations of AMPT and calculations from heavy quark pQCD model, NLO(MNR) have been used for the study of $p_T$ dependent nuclear modification factors in terms of collision centrality ($\displaystyle{Q_{pPb}}$) and the central-to-peripheral ratios ($\displaystyle{Q_{cp}}$) of D mesons. It is found that NLO model with its parametrized $\displaystyle{k_T}$ broadening scheme p…
We investigate the centrality-dependent validity of the limiting-fragmentation hypothesis in relativistic heavy-ion collisions at energies reached at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC). A phenomenological analysis of Au-Au and Pb-Pb collisions within a three-source relativistic diffusion model (RDM) is performed at sqrt(s_NN) = 19.6, 62.4, 130, 200, 2760 and 5023 GeV using four centrality cuts at each energy. Linear and nonlinear expressions for the rapidity drift function are tested and their physical relevance is discussed. Our results are compatib…
The transverse momentum (pt) dependence, the centrality dependence and the rapidity dependence of the elliptic flow of thermal photons in Au+Au collisions at $\sqrt{s_{NN}}=200$ GeV are predicted, based on a three-dimensional ideal hydrodynamic description of the hot and dense matter. The elliptic flow parameter $v_{2}$, i.e. the second Fourier coefficient of azimuthal distribution, of thermal photons, first increases with $\pt$ and then decreases for $\pt>$ 2 GeV/$c$, due to the weak transverse flow at the early stage. The $\pt$-integrated $v_{2}$ first increases with centrality, reaches a ma…
The centrality dependence of charged-hadron production in relativistic heavy-ion collisions at LHC energies is investigated in a nonequilibrium-statistical relativistic diffusion model (RDM) with three sources. Theoretical pseudorapidity distributions are compared with preliminary PbPb ALICE data at LHC energy of sqrt(s_NN) = 2.76 TeV for seven centralities, and a previous RDM prediction for this energy is confronted with the data. Refined predictions for 5.52 TeV PbPb based on RDM parameter extrapolations are presented.
We show that the QCD color transparency of higher-twist contributions to inclusive hadroproduction cross sections, where baryons are produced directly in a short-distance subprocess, can explain several remarkable features of high-$p_T$ baryon production in heavy ion collisions which have recently been observed at RHIC: (a) the anomalous increase of the proton-to-pion ratio with centrality (b): the increased power-law fall-off at fixed $x_T=2p_T/ \sqrt s$ of the charged particle production cross section in high centrality nuclear collisions, and (c): the anomalous decrease of the number of sam…
We explore the centrality dependence of properties of the dense hadronic matter created in \sqrt{s_{NN}}=200 GeV Au--Au collisions at RHIC. Using the statistical hadronization model we fit particle yields known for 11 centrality bins. We present the resulting model parameters, rapidity yields of physical quantities and the physical properties of bulk matter at hadronization as function of centrality. We discuss the production of strangeness and entropy.
Transverse Spherocity is an event structure variable which provide an effective way to disentangle the data into hard and soft components of the processes corresponding to events with small and large numbers of multi-parton interactions (MPI), respectively. Recent experimental results in small systems from the LHC suggest the importacnce of transverse spherocity variable in the classification of the events. In this contribution, we have studied the dynamics of identified particle production in Xe-Xe collisions at $\sqrt{s_{NN}}$ = 5.44 TeV using A Multi-Phase Transport Model (AMPT) and the rec…
This is the second part of a two-part article on precision modeling of identified-hadron (PID) $p_t$ spectra from 5 TeV $p$-Pb collisions. In Part I a revised two-component (soft + hard) model (TCM) of PID spectra was introduced, an apparent detection inefficiency for protons was corrected and jet-related spectrum hard components isolated via an improved method were compared to a fixed TCM serving as reference. In the present article (Part II) the TCM is further elaborated to describe centrality variation of spectrum hard components (and therefore entire spectra) within data statistical uncert…
In this study, we systematically investigate deformed Xe-Xe collisions at 5.44 TeV center of mass energy. We exploit the Monte Carlo HYDJET++ model to compute transverse momentum ($p_{T}$) distribution, nuclear modification factor $R_{AA}$ and relative suppression in terms of $R_{CP}$ as a function of transverse momentum and centrality of collision of charged hadrons in body-body and tip-tip geometrical configurations, respectively. We have compared HYDJET++ model results to those from ALICE experimental data and AMPT model (String-Melting version) results. Minimum bias Xe-Xe collisions show a…
Kinetic Freeze-Out Properties from Transverse Momentum Spectra of kaon, Pion, and (anti-)proton production in U+U collisions at $\sqrt{s_{NN}}$ = 193 GeV
To reduce the effect of the fluctuations of initial geometrical shape, elliptic flow are studied at fixed centrality in Au+Au collision at $\sqrt{s_{\rm NN}}$=200GeV. It is observed with the participant increasing, elliptic flow has an increase and a decrease at different fixed impact parameter, but not a trivial fluctuation. It is analyzed that the initial space anisotropy dominates the participant dependence of elliptic flow in near-central collisions(b=5fm) and mid-central collisions(b=8fm), while the interaction between particles can mainly answer for the behavior of elliptic flow in perip…
Deconfined QCD matter in heavy-ion collisions has been a topic of paramount interest for many years. Quarkonia suppression in heavy-ion collisions at the Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) experiments indicate the quark-gluon plasma (QGP) formation in such collisions. Recent experiments at LHC has given some indications of hot matter effect in asymmetric p$-$Pb nuclear collisions. Here, we employ a theoretical model to investigate the bottomonium suppression in Pb$-$Pb at $\sqrt{s_{NN}}=2.76$, $5.02$ TeV, and in p$-$Pb at $\sqrt{s_{NN}}=5.02$ TeV center-of-m…
Utilizing the three-fireball picture within the quark combination model, we study systematically the charged particle pseudorapidity distributions in both Au+Au and Cu+Cu collision systems as a function of collision centrality and energy, $\sqrt{s_{NN}}=$ 19.6, 62.4, 130 and 200 GeV, in full pseudorapidity range. We find that: (i)the contribution from leading particles to $dN_{ch}/dη$ distributions increases with the decrease of the collision centrality and energy respectively; (ii)the number of the leading particles is almost independent of the collision energy, but it does depend on the nucl…
The transverse momentum spectra of seven identified hadrons produced in Pb+Pb collisions at $\sqrt{s_{NN}}=2.76$ and 5.02 TeV at the CERN Large Hadron Collider (LHC) have been investigated in the framework of the recombination model (RM). Soft, semihard and hard partons all play important roles in our model and are uniformly treated for all hadrons produced.The investigation has been extended to non-central collisions and the parameters controlling the momentum degradation of semihard partons have been tuned. Our study shows good agreement between theoretical results and experimental data. To …
We have carried out a wide study of shadowing and antishadowing effects on \jpsi\ production in \dAu\ collisions at $\sqrt{s_{NN}}=200$ GeV. We have studied the effects of three different gluon nPDF sets, using the exact kinematics for a $2\to 2$ process, namely $g+g\to J/ψ+g$ as expected from LO pQCD. We have computed the rapidity dependence of \RCP\ and $R_{d\rm Au}$ for the different centrality classes of the PHENIX data. For mid rapidities, we have also computed the transverse-momentum dependence of the nuclear modification factor, which cannot be predicted with the usual $2\to 1$ simplifi…
The centrality dependence of the $p/π$ ratio measured by the ALICE Collaboration in 5.02 TeV Pb-Pb collisions indicates a statistically significant suppression with the increase of the charged particle multiplicity once the centrality-correlated part of the systematic uncertainty is eliminated from the data. We argue that this behavior can be attributed to baryon annihilation in the hadronic phase. By implementing the $B\bar{B} \leftrightarrow 5π$ reaction within a generalized partial chemical equilibrium framework, we estimate the annihilation freeze-out temperature at different centralities,…
The $p$-Pb collision system occupies a unique position regarding physical interpretation of high-energy particle data. More-peripheral $p$-Pb is indistinguishable from $p$-$p$ collision while more-central $p$-Pb overlaps an interval of Pb-Pb centrality wherein it has been claimed that quark-gluon plasma (QGP) formation is achieved. One basis for such claims is certain features and centrality trends of identified-hadron (PID) $p_t$ spectra, including similarities between $p$-Pb and Pb-Pb spectra. In order to verify or falsify such claims it is essential that PID spectra for $p$-Pb collisions (a…
The centrality dependence of pseudorapidity density of charged particles and transverse energy is studied for a wide range of collision energies for heavy-ion collisions at midrapidity from 7.7 GeV to 5.02 TeV. A two-component model approach has been adopted to quantify the soft and hard components of particle production, coming from nucleon participants and binary nucleon-nucleon collisions, respectively. Within experimental uncertainties, the hard component contributing to the particle production has been found not to show any clear collision energy dependence from RHIC to LHC. The effect of…
In this paper, we study and predict the charged-particle pseudorapidity multiplicity density ($\frac{dN_{ch}}{dη}$), transverse momentum spectra of identified particles and their ratios in relativistic heavy ion collisions at the Large Hadron Collider (LHC), using the string-melting version of a multi-phase transport (AMPT) model with improved quark coalescence method. Results of the charged-particle pseudorapidity multiplicity density from AMPT model calculations for Pb+Pb collisions at $\sqrt{s_{NN}}=5.02$ TeV are compared with the experimental data. Good agreements are generally found betwe…
Anomalous centrality evolution of two-particle angular correlations observed in Au-Au collisions at $\sqrt{s_{NN}} = 62$ and 200 GeV and the onset of ridge structures are considered in the model of interacting quark-gluon strings. We assume that at the given energy of nucleus-nucleus collisions the critical energy density may be reached at the specific centrality. In a string percolation model this might be treated equivalently to a formation of a large cluster of strings characterized by the critical string density, with a size comparable to the whole area of interaction of two nuclei. This h…
We report on our studies of the neutron-skin effects in high-$p_{\mathrm{T}}$ observables at the LHC. We study the impact of the neutron-skin effect on the centrality dependence of inclusive direct photon, high-$p_{\mathrm{T}}$ hadron and $W^{\pm}$ production in nuclear collisions at the LHC. The neutron-skin effect refers to the observation that in spherical heavy nuclei, the tail of the neutron distribution extends farther than the distribution of protons, which can affect observables sensitive to electroweak phenomena in very peripheral collisions. We quantify this effect for direct photons…
The centrality dependence of thermal parameters, characterizing the hadron multiplicities, is determined phenomenologically for lead-on-lead collisions at CERN-SPS for a beam energy of 158 AGeV. The strangeness equilibration factor shows a clear, approximately linear, increase with increasing centrality, while the freeze-out temperature and chemical potential remain constant.
We obtain strangeness production as function of centrality in a statistical hadronization model analysis of all experimental hadron production data in Au--Au collisions at $\sqrt{s_{NN}}=62.4\GeV$. Our analysis describes successfully the yield of strange and multi-strange hadrons recently published. We explore condition of hadronization as a function of centrality and find universality for the case of chemical non-equilibrium in the hadron phase space corresponding to quark--gluon plasma (QGP) in chemical equilibrium.
The deuteron binding energy is only 2.2 MeV. At the same time, its yield in Pb+Pb collisions at $\sqrt{s_{NN}} = $2.76 TeV corresponds to a thermal yield at the temperature around 155 MeV, which is too hot to keep deuterons bound. This puzzle is not completely resolved yet. In general, the mechanism of light nuclei production in ultra-high energy heavy ion collisions remains under debate. In a previous work [1] we suggest a microscopic explanation of the deuteron production in central ultra-relativistic Pb+Pb collisions, the main mechanism being $πpn \leftrightarrow πd$ reactions in the hadron…
We have estimated centrality variation of chemical freeze-out parameters from yield data at mid-rapidity of $π^\pm$, $K^\pm$ and $p$, $\bar{p}$ for collision energies of RHIC (Relativistic Heavy Ion Collider), Beam Energy Scan (RHIC-BES) program, and LHC (Large Hadron Collider). We have considered a simple hadron resonance gas model and employed a formalism involving conserved charges ($B, Q, S$) of QCD for parameterization. Along with temperature and three chemical potentials ($T,μ_B,μ_Q,μ_S$), a strangeness under-saturation factor ($γ_S$) has been used to incorporate the partial equilibratio…
Using iEBE-VISHNU hybrid model with the AMPT initial conditions, we study the higher order flow harmonics of identified hadrons in 2.76 A TeV Pb+Pb collisions. Comparison with the recent ALICE measurements at 20-30\% centrality shows that our calculations nicely describe the data below 2 GeV, especially for the $v_2$, $v_3$ and $v_4$ mass-orderings among pions, kaons and protons. We also extended the calculations to other centrality bins, which presents similar mass-ordering patterns for these flow harmonics as the ones observed at 20-30\% centrality. In the later part of this article, we expl…
Measurements of the dynamical correlations between neutral and charged kaons in central Pb-Pb collisions at $\sqrt{s_{NN}} = 2.76$ TeV by the ALICE Collaboration display anomalous behavior relative to conventional heavy-ion collision simulators such as AMPT, EPOS, and HIJING. We consider other conventional statistical models, none of which can reproduce the magnitude and centrality dependence of the correlations. The data can be reproduced by coherent emission from domains which grow in number and volume with increasing centrality. We show that the energy released by condensation of strange qu…
We study the production of charmonia and charmed hadrons in nucleus-nucleus collisions at SPS, RHIC, and LHC energies within the framework of the statistical hadronization model. Results from this model are compared to the measured yields and centrality dependence of J/psi production at SPS and RHIC energies. We explore and contrast the centrality dependence of the production of mesons with open and hidden charm at SPS, RHIC, and LHC. The sensitivity of the results to various input parameters is analyzed in detail for RHIC energy.
We estimate chemical freeze-out parameters in HRG and EVHRG model by fitting the experimental information of net-proton and net-charge fluctuations measured in Au + Au collisions by the STAR collaboration at RHIC. We observe that chemical freeze-out parameters obtained from lower and higher order fluctuations are though almost same for $\sqrt{s_{NN}} > 27$ GeV, tend to deviate from each other at lower $\sqrt{s_{NN}}$. Moreover, these separations increase with decrease of $\sqrt{s_{NN}}$ and for a fixed $\sqrt{s_{NN}}$ increase towards central collisions. Furthermore, we observe an approximate …
Charged particles $p_T$ spectra and elliptic flow in 0-60% Au+Au collisions at RHIC are analyzed in a hydrodynamic model with hot, hadronic resonance gas in the initial state. Physically conceivable hadronic resonance gas, thermalized in the time scale $τ_i$=1 fm, at a (central) temperature $T_i$=220 MeV, with viscosity to entropy ratio $η/s$=0.24, reasonably well explains $p_T$ spectra in all the collision centralities. Centrality dependence of elliptic flow however demands continual increase of viscosity to entropy ratio with centrality.
Hadron multiplicity in the central rapidity region of high-energy heavy-ion collisions is investigated within a two-component mini-jet model which consists of soft and semi-hard particle production. The hard contribution from mini-jets is reevaluated using the latest parameterization of parton distributions and nuclear shadowing. The energy dependence of the experimental data from RHIC requires a strong nuclear shadowing of the gluon distribution in this model. The centrality dependence of the hadron multiplicity at $\sqrt{s}=130$ GeV is reproduced well with the impact-parameter dependent part…
We investigate the properties of light (anti)nuclei and (anti)hypertriton production in Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}=2.76$ TeV, based on the parton and hadron cascade and dynamically constrained phase-space coalescence (PACIAE + DCPC) model. We found that the yields of light (anti)nuclei and (anti)hypertriton strongly depend on the centrality, i.e., their yields decrease rapidly with the increase of centrality bins, but their yield ratios are independent of centrality. The results of theoretical model are well consistent with ALICE data. Furthermore, we found that the integrated yie…
In the Israel-Stewart's theory of second order hydrodynamics, we have simulated $\sqrt{s}$=2.76 TeV Pb+Pb collisions. ALICE data for the centrality dependence of charged particles multiplicity, $p_T$ spectra in 0-5% collisions, centrality dependence of integrated and differential elliptic flow are analysed. Analysis indicate that while ALICE data on charged particles multiplicity or $p_T$ spectra do not demand any viscosity, viscosity is demanded by the elliptic flow data. From a simulataneous fit to all the data sets, viscosity to entropy ratio in $\sqrt{s}_{NN}$=2.76 TeV Pb+Pb collisions is …
Centrality dependence of charged particles multiplicity, transverse momentum spectra, integrated and differential elliptic flow, in $\sqrt{s}_{NN}$=200 GeV Au+Au collisions are analyzed using event by event ideal hydrodynamics. Monte-Carlo Glauber model of initial condition, constrained to reproduce experimental charged particle's multiplicity in 0-10% Au+Au collisions, reasonably well reproduces all the experimental observables, e.g. centrality dependence of charged particles multiplicity, integrated and differential elliptic flow. Model predictions for higher flow harmonics, $v_3$, $v_4$ how…
We study the influence of the centrality definition and detector efficiency on the net-proton kurtosis for minimum bias Au+Au collisions at a beam energy of $\sqrt{s_{\mathrm{NN}}}= 7.7$ GeV by using the UrQMD model. We find that different ways of defining the centrality lead to different cumulant ratios. Moreover, we demonstrate that the kurtosis is suppressed for central collisions when a wider transverse momentum acceptance is used. Finally, the influence of a detector efficiency on the measured cumulant ratios is estimated.
We derive a simple analytical scaling function which embodies the predictions of high density QCD on the energy, centrality, rapidity, and atomic number dependences of hadron multiplicities in nuclear collisions. Both centrality and rapidity dependences of hadron multiplicity in $Au-Au$ collisions as measured at RHIC at $\sqrt{s}= 130 {GeV}$ are well described in this approach. The centrality and rapidity dependences of hadron multiplicity at $\sqrt{s}= 200 \ {GeV}$ run at RHIC are predicted; the variation of these dependences with energy appear different from other approaches, and can be used…
We argue that gluon saturation effects may be visible in Large Hadron Collider (LHC) data. We look at the centrality dependence of the away-side peak of two-particle correlations measured in p-Pb collisions, using both ALICE data at midrapidity, and LHCb data at forward rapidity. Once the collective flow-like signal measured at the near-side peak is removed from the correlation function, the centrality dependence of the away-side peak turns out to be much stronger in the forward region than at midrapidity. We argue that this is a very specific prediction of the saturation framework, and we com…
Centrality-dependent double-differential transverse momentum spectra of charged pions, kaons, and (anti)protons produced in mid-pseudorapidity interval in $\sqrt{s_{NN}}=200$ GeV gold-gold and deuteron-gold collisions with different centralities are analyzed by the blast-wave model with Boltzmann-Gibbs statistics. Meanwhile, the mentioned spectra in mid-rapidity interval in $\sqrt{s_{NN}}=2.76$ TeV lead-lead and $\sqrt{s_{NN}}=5.02$ TeV proton-lead collisions with different centralities are analyzed by the same model. The model results are approximately in agreement with the experimental data …
