This work presents a Bayesian inference study for relativistic heavy-ion collisions in the Beam Energy Scan program at the Relativistic Heavy-Ion Collider. The theoretical model simulates event-by-event (3+1)D collision dynamics using hydrodynamics and hadronic transport theory. We analyze the model's 20-dimensional posterior distributions obtained using three model emulators with different accuracy and demonstrate the essential role of training an accurate model emulator in the Bayesian analysis. Our analysis provides robust constraints on the Quark-Gluon Plasma's transport properties and various aspects of (3+1)D relativistic nuclear dynamics. By running full model simulations with 100 parameter sets sampled from the posterior distribution, we make predictions for $p_{\rm T}$-differential observables and estimate their systematic theory uncertainty. A sensitivity analysis is performed to elucidate how individual experimental observables respond to different model parameters, providing useful physics insights into the phenomenological model for heavy-ion collisions.
We investigate the collision energy dependence of $η/s$ in a transport + viscous hydrodynamics hybrid model. A Bayesian analysis is performed on RHIC beam energy scan data for $Au+Au$ collisions at $\sqrt{s_{NN}}=19.6,39,$ and $62.4$ GeV. The resulting posterior probability distributions for the model parameters show a preference for a larger value of $η/s$ at $19.6$ GeV compared to $62.4$ GeV, indicating dependence on baryon chemical potential $μ_B$.
Polarization of $Λ$ hyperons and their antiparticles is calculated in a 3+1 dimensional viscous hydrodynamic model with initial state from UrQMD hadron/string cascade. We find that, along with recent results from STAR, the mean polarization at fixed centrality decreases as a function of collision energy from 1.5% at $\sqrt{s_{\rm NN}}=7.7$ GeV to 0.2% at $\sqrt{s_{\rm NN}}=200$ GeV. We explore the effects which lead to such collision energy dependence, feed-down corrections and a difference between $Λ$ and $\barΛ$.
A state-of-the-art 3+1 dimensional cascade + viscous hydro + cascade model vHLLE+UrQMD has been applied to heavy ion collisions in RHIC Beam Energy Scan range $\sqrt{s_{\rm NN}}=7.7\dots 200$ GeV. Based on comparison to available experimental data it was estimated that an effective value of shear viscosity over entropy density ratio $η/s$ in hydrodynamic stage has to decrease from $η/s=0.2$ to $0.08$ as collision energy increases from $\sqrt{s_{\rm NN}} = 7.7$ to $39$ GeV, and to stay at $η/s=0.08$ for $39\le\sqrt{s_{\rm NN}}\le200$ GeV. In this work we show how an equation of state with first…
The centrality dependence of spectra of identified particles in collisions between ultrarelativistic heavy ions with a center of mass energy ($\sqrt{s}$) of 39 and 11.5 $AGeV$ is analyzed in the core - corona model. We show that at these energies the spectra can be well understood assuming that they are composed of two components whose relative fraction depends on the centrality of the interaction: The core component which describes an equilibrated quark gluon plasma and the corona component which is caused by nucleons close to the surface of the interaction zone which scatter only once and wh…
We systematically compare an event-by-event transport+viscous hydrodynamics hybrid model to data from the RHIC beam energy scan using a general Bayesian method. We demonstrate how the inclusion of multistrange hadron observables affects the outcome of the Bayesian analysis and conduct an in depth analysis of the viability of $ϕ$ and $Ω$ as probes of the transition region between a deconfined quark-gluon plasma and hadronic phase in heavy ion collisions at higher-end RHIC collision energies. Utilizing UrQMD to model the final hadronic interactions, we examine the collision rates of $ϕ$ and $Ω$ …
We present the first results using the STAR detector from the Beam Energy Scan (BES) program at the Relativistic Heavy-Ion Collider (RHIC). In this program, Au ion collisions at center of mass energies (\sqrt{s_{NN}}) of 7.7, 11.5 and 39 GeV allowed RHIC to extend the study of the QCD phase diagram from baryonic chemical potential values of 20 MeV to about 400 MeV. For the high net-baryon density matter at midrapidity, formed in these collisions, we report several interesting measurements. These include the observation of difference between anti-particle and particle elliptic flow, disappearan…
Currently the RHIC Beam Energy Scan is exploring a new region of the Quantum Chromodynamic phase diagram at large baryon densities that approaches nuclear astrophysics regimes. This provides an opportunity to study relativistic hydrodynamics in a regime where the net conserved charges of baryon number, strangeness, and electric charge play a role, which will significantly change the theoretical approach to simulating the baryon-dense Quark-Gluon Plasma. Here we detail many of the important changes needed to adapt both initial conditions and the medium to baryon-rich matter. Then, we make basel…
We study the transverse momentum spectra of light nuclei (deuteron, anti-deuteron and triton) produced in Gold-Gold (Au-Au) collisions in different centrality bins by the blast wave model with Tsallis statistics. The model results are in agreement with the experimental data measured by STAR Collaboration in special transverse momentum ranges. We extracted the kinetic freezeout temperature, transverse flow velocity and kinetic freezeout volume. It is observed that kinetic freezeout temperature and transverse flow velocity increases initially, and then saturates from 14.5-39 GeV, while the kinet…
Extension of the integrated hydrokinetic model to nuclear collision energies relevant for the RHIC Beam-Energy Scan program and the research program at GSI-FAIR
With the kinetic freeze-out nucleons and antinucleons obtained from the quark combination model, we study the production of light nuclei and antinuclei in the (anti-)nucleon coalescence mechanism in relativistic heavy ion collisions. We derive analytic formulas of the momentum distributions of different light nuclei and apply them to compute transverse momentum ($p_T$) spectra of (anti-)deuterons ($d$, $\bar d$) and (anti-)tritons ($t$, $\bar t$) in Au-Au collisions at $\sqrt{s_{NN}}=$7.7, 11.5, 19.6, 27, 39, 54.4 GeV. We find that the experimental data available for these $p_T$ spectra can be…
The parton and hadron cascade model PACIAE is used to investigate strange particle production in Au + Au collisions at GeV in different centralities and at 39, 11.5 and 7.7 GeV in the most central collision, respectively. It is shown that the transverse momentum distributions of strange particles by the PACIAE model fit the RHIC Beam Energy Scan experimental results well.
We study the directed flow of identified particles in Au+Au collisions at $\sqrt{s_\text{NN}}=7.7$ to 62.4 GeV. The Glauber model is extended to include both a tilted deformation of the QGP fireball with respect to the longitudinal direction and a non-zero longitudinal flow velocity gradient in the initial state. By combining this improved initial condition with a (3+1)-dimensional viscous hydrodynamic model calculation, we obtain a satisfactory description of the transverse momentum spectra and the rapidity dependent directed flow coefficient of different hadron species. Our calculation indic…
In terms of the hadron-string-dynamics (HSD) approach we investigate the correlation function in the azimuthal angle $ψ$ of charged hadrons that is expected to be sensitive to a signal of local strong parity violation. Our analysis of Au+Au collisions is based on the recent STAR data within the RHIC Beam-Energy-Scan (BES) program. The HSD model reasonably reproduces STAR data for $\sqrt{s_{NN}}=$7.7 GeV, while there are some deviations from the experiment at the collision energy of 11.5 GeV and an increase of deviations between theory and experiment at $\sqrt{s_{NN}}=$39 GeV. For reference, th…
Based on the data-driven analysis, the mid-rapidity transverse momentum spectra of charged hadrons produced in central and peripheral gold-gold (Au-Au) collisions from the Beam Energy Scan (BES) program at the relativistic Heavy Ion Collider (RHIC) are fitted by the blast-wave model with Boltzmann-Gibbs statistics. The model result are in agreement with the experimental data measured by the STAR Collaboration at the RHIC-BES energies. We observe that the kinetic freeze-out temperature, transverse flow velocity, mean transverse momentum, and initial temperature increase with the collision energ…
The STAR detector at RHIC, due to its large uniform acceptance and excellent particle identification capabilities, has measured a variety of hadron species ($π^{\pm}$, $K^{\pm}$, $p$, $\bar{p}$, $K^{0}_{S}$, $Λ$, $\barΛ$, $Ξ^{-}$, $\barΞ^{+}$) produced in Au+Au collisions at $\sqrt {s_{NN}}= 7.7$, 11.5, 27 and 39 GeV. These data are part of the Beam Energy Scan (BES) program at RHIC and provide an opportunity to measure the yields and transverse momentum spectra ($p_{T}$) of the particles produced in the collisions. The corresponding measurements allow to study the freeze-out properties and dy…
Following the experimental program at BNL RHIC, we perform a similar "energy scan" using 3+1D viscous hydrodynamics coupled to the UrQMD hadron cascade, and study the collision energy dependence of pion and kaon rapidity distributions and $m_T$-spectra, as well as charged hadron elliptic flow. To this aim the equation of state for finite baryon density from a Chiral model coupled to the Polyakov loop is employed for hydrodynamic stage. 3D initial conditions from UrQMD are used to study gradual deviation from boost-invariant scaling flow. We find that the inclusion of shear viscosity in the hyd…
We report results of $v_1(y)$ and $dv_1/dy$ near mid-rapidity for $π^{\pm}$, $K^{\pm}$, $K_s^0$, $p$, $\overline{p}$, $Λ$, $\overlineΛ$ and $ϕ$ from Beam Energy Scan Au+Au collisions at $\sqrt{s_{NN}} = $ 7.7 - 200 GeV using the STAR detector at RHIC. The $dv_{1}/dy$ of $π^{\pm}$, $K^{\pm}$ and $K_s^0$ mesons remains negative over all beam energies. The $dv_1/dy$ of $p$ and $Λ$ baryons shows a sign change around 10 - 15 GeV, while net baryons (net p and net $Λ$) indicate a double sign change. The $dv_1/dy$ of $\overline{p}$, $\overlineΛ$ and $ϕ$ show a similar trend for $\sqrt{s_{NN}}>$ 14.5 G…
In this paper, we investigate the kinetic freeze-out properties in relativistic heavy ion collisions at different collision energies. We present a study of standard Boltzmann-Gibbs Blast-Wave (BGBW) fits and Tsallis Blast-Wave (TBW) fits performed on the transverse momentum spectra of identified hadrons produced in Au + Au collisions at collision energies of $\sqrt{s_{\rm{NN}}}=$ 7.7 - 200 GeV at the Relativistic Heavy Ion Collider (RHIC), and in Pb + Pb collisions at collision energies of $\sqrt{s_{\rm{NN}}}=$ 2.76 and 5.02 TeV at the Large Hadron Collider (LHC). The behavior of strange and m…
We present a fully three-dimensional initial state model for relativistic heavy-ion collisions at RHIC Beam Energy Scan (BES) collision energies. The initial energy and net baryon density profiles are produced based on a classical string deceleration model. The baryon stopping and fluctuations during this early stage of the collision are investigated by studying the net baryon rapidity distribution and longitudinal decorrelation of the transverse geometry.
The elliptic flow splitting between particles and their antiparticles has recently been observed by the STAR Collaboration in the beam-energy scan program at the Relativistic Heavy Ion Collider. In studies based on transport models, we have found that this splitting can be explained by the different mean-field potentials acting on particles and their antiparticles in the produced baryon-rich matter. In particular, we have shown that the experimentally measured relative elliptic flow difference can help constrain the vector coupling constant in the Nambu-Jona-Lasinio model used in describing th…
We calculate the mean-over-variance ratio of the net-kaon fluctuations in the Hadron Resonance Gas (HRG) Model for the five highest energies of the RHIC Beam Energy Scan (BES) for different particle data lists. We compare these results with the latest experimental data from the STAR collaboration in order to extract sets of chemical freeze-out parameters for each list. We focused on the PDG2012 and PDG2016+ particle lists, which differ largely in the number of resonant states. Our analysis determines the effect of the amount of resonances included in the HRG on the freeze-out conditions.
Experimental results of the transverse momentum distributions of phi mesons and $Ω$ hyperons produced in gold-gold (Au-Au) collisions with different centrality intervals, measured by the STAR Collaboration at different energies (7.7, 11.5, 19.6, 27, and 39 GeV) in the beam energy scan (BES) program at the relativistic heavy ion collider (RHIC), are approximately described by the single Erlang distribution and the two-component Schwinger mechanism. Meanwhile, the STAR experimental transverse momentum distributions of negatively charged particles, produced in Au-Au collisions at RHIC BES energie…
Fluctuations of conserved quantities, such as baryon, electric charge and strangeness number, are sensitive observables in relativistic heavy-ion collisions to probe the QCD phase transition and search for the QCD critical point. In this paper, we review the experimental measurements of the cumulants (up to fourth order) of event-by-event net-proton (proxy for net-baryon), net-charge and net-kaon (proxy for net-strangeness) multiplicity distributions in Au+Au collisions at $\sqrt{s_{NN}}=7.7, 11.5, 14.5, 19.6, 27, 39, 62.4, 200$ GeV from the first phase of beam energy scan program at the Relat…
Using a hybrid (viscous hydrodynamics + hadronic cascade) framework, we model the bulk dynamical evolution of relativistic heavy-ion collisions at Relativistic Heavy Ion Collider (RHIC) Beam Energy Scan (BES) collision energies, including the effects from non-zero net baryon current and its dissipative diffusion. This framework is in full (3+1)D, which allows us to study the non-trivial longitudinal structure and dynamics of the collision systems, for example baryon stopping and transport, as well as longitudinal fluctuations. For the first time, the quantitative effect of net-baryon diffusion…
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…
Recent pT<2~GeV azimuthal correlation data from the Beam Energy Scan (BES) and D+Au runs at RHIC/BNL and, especially, the surprising similarity of azimuthal $v_n\{2m\}(p_T)$ ``transeverse flow'' harmonics in $p+Pb$ and $Pb+Pb$ at LHC have challenged the uniqueness of local equilibrium ``perfect fluid'' interpretations of those data. We report results at QM14 on azimuthal harmonics associated with initial-state non-abelian ``wave interference'' effects predicted by perturbative QCD gluon bremsstrahlung and sourced by Color Scintillation Arrays (CSA) of color antennas. CSA are naturally identifi…
We calculate the polarization of $Λ$ hyperons in Au-Au collisions at RHIC Beam Energy Scan range $\sqrt{s_{\rm NN}}=7.7, \dots, 200$ GeV in a state-of-the-art 3+1 dimensional cascade + viscous hydro model vHLLE+UrQMD. We find that the polarization of $Λ$ in the out-of-plane direction decreases substantially with collision energy. We explore the connection between the polarization signal and thermal vorticity and discuss the feed-down and hadronic rescattering effects on the mean polarization of all produced $Λ$ hyperons.
The search for a possible critical point in the QCD phase diagram is ongoing in heavy ion collision experiments at RHIC which scan the phase diagram by scanning the beam energy; a coming upgrade will increase the luminosity and extend the rapidity acceptance of the STAR detector. In fireballs produced in RHIC collisions, the baryon density depends on rapidity. By employing Ising universality together with a phenomenologically motivated freezeout prescription, we show that the resulting rapidity dependence of cumulant observables sensitive to critical fluctuations is distinctive. The dependence…
Using the moments of the net-kaon distribution calculated within a state of-the-art hadron resonance gas model compared to experimental data from STAR's Beam Energy Scan, we find that the extracted strange freeze-out temperature is incompatible with the light one extracted from net-proton and net-charge fluctuations. Additionally predictions for net-$Lambda$ fluctuations are made that also appear to be consistent with a higher freeze-out temperature for strange particles. This strangeness freeze-out temperature is roughly $10-15$ MeV higher than the corresponding light freeze-out temperature. …
We analyze longitudinal pion spectra from \sqrt{s_{NN}}= 2 GeV to \sqrt {s_{\rm NN}}=20 GeV within Landau's hydrodynamical model and the UrQMD hybrid approach. From the measured data on the widths of the pion rapidity spectra, we extract the sound velocity c_s^2 in the dense stage of the reactions. It is found that the sound velocity has a local minimum (indicating a softest point in the equation of state, EoS) at \sqrt{s_{NN}}= 4-9 GeV, an energy range accessible at the Facility for Antiproton and Ion Research (FAIR) as well as the RHIC-Beam Energy Scan (RHIC-BES). This softening of the EoS i…
Beam energy scan programs in heavy-ion collisions aim to explore the QCD phase structure at high baryon density. Sensitive observables are applied to probe the signatures of the QCD phase transition and critical point in heavy-ion collisions at RHIC and SPS. Intriguing structures, such as dip, peak and oscillation, have been observed in the energy dependence of various observables. In this paper, an overview is given and corresponding physics implications will be discussed for the experimental highlights from the beam energy scan programs at the STAR, PHENIX and NA61/SHINE experiments. Further…
In hydrodynamic approach to relativistic heavy ion collisions, hadrons with nonzero spin, produced out of the hydrodynamic medium, can acquire polarization via spin-vorticity thermodynamic coupling mechanism. The hydrodynamical quantity steering the polarization is the thermal vorticity, that is minus the antisymmetric part of the gradient of four-temperature field. Based on this mechanism there have been several calculations in hydrodynamic and non-hydrodynamic models for non-central heavy ion collisions in the RHIC Beam Energy Scan energy range, showing that the amount of polarization of pro…
STAR collaboration at RHIC has recently measured the polarization of $Λ$ hyperons in non-central heavy ion collisions in the RHIC Beam Energy Scan (BES) program. The magnitude of the polarization was found to decrease from few percents at the lowest BES energies to $\approx0.2$% at the top RHIC energy. The polarization signal has been reproduced in different hydrodynamic calculations assuming a thermodynamic spin-vorticity coupling mechanism at the Cooper-Frye hypersurface. In this work an extension of our existing calculations of the $Λ$ polarization in the RHIC BES program to the top RHIC an…
We present calculations of dilepton and photon spectra for the energy range $E_{\text{lab}}=2-35$ $A$GeV which will be available for the Compressed Baryonic Matter (CBM) experiment at the future Facility for Anti-Proton and Ion Research (FAIR). The same energy regime will also be covered by phase II of the Beam Energy Scan at the Relativistic Heavy-Ion Collider (RHIC-BES). Coarse-grained dynamics from microscopic transport calculations of the Ultra-relativistic Quantum Molecular Dynamics (UrQMD) model is used to determine temperature and chemical potentials, which allows for the use of dilepto…
The energy dependence of the local ${\cal P}$ and ${\cal CP}$ violation in Au+Au and Cu+Cu collisions in a large energy range is estimated within a simple phenomenological model. It is expected that at LHC the chiral magnetic effect will be about 20 times weaker than at RHIC. At lower energy range, covered by the low-energy scan at RHIC and future NICA/FAIR facilities, the created magnetic field strength and energy density of deconfined matter are rather high providing necessary conditions for the chiral magnetic effect. However, the particular model for the chiral magnetic effect predicts tha…
The recent net-proton fluctuation results of the STAR (Solenoidal Tracker At RHIC) experiment from beam energy scan (BES) program at the BNL Relativistic Heavy Ion Collider (RHIC) have drawn much attention to exploring the QCD critical point and the nature of deconfinement phase transition. There has been much speculation that the non-monotonic behavior of $κσ^{2}$ of the produced protons around $\sqrt{s_{\rm NN}}$ = 19.6 GeV in the STAR results may be due to the existence of QCD critical point. However, the experimentally measured proton distributions contain protons from heavy resonance deca…
Longitudinal Dynamics of Large and Small Systems from a 3D Bayesian Calibration of RHIC Top-energy Collision Data
Vanderbilt University（范德堡大学）；Wayne State University（韦恩州立大学）；RIKEN BNL Research Center, Brookhaven National Laboratory（理化学研究所布鲁克海文研究中心，布鲁克海文国家实验室）；Universidade de São Paulo（圣保罗大学）；Duke University（杜克大学）；McGill University（麦吉尔大学）；University of California, Berkeley（加州大学伯克利分校）；Lawrence Berkeley National Laboratory（劳伦斯伯克利国家实验室）；Universidade Federal Fluminense（弗鲁米嫩塞联邦大学）
The freeze-out curve, which describes a vast amount of precise experimental data in heavy ion collisions, provides a relation between the colliding energy and the thermodynamical parameters of the fireball. The variance, skew and kurtosis of the event distribution of baryon number are studied at several energies of interest through Pade resummations of our Lattice QCD results. A smooth behaviour is predicted for three ratios of these quantities at current RHIC and future LHC energies. Any deviations from these at the RHIC energy scan would signal the presence of a nearby critical point. Our la…
The Chiral Magnetic Effect (CME) is predicted for Au-Au collisions at RHIC. However many backgrounds can give signals that make the measurement hard to interpret. The STAR experiment has made measurements at different collisions energy ranging from $\sqrt{s_{NN}}$=7.7 GeV to 62.4 GeV. In the analysis that is presented we show that the CME turns on with energy and is not present in central collisions where the induced magnetic is small.
Taking into account the finiteness of the system created in heavy ion collisions, we show sizable results for the modifications of the chiral phase diagram at volume scales typically encountered in current experiments and demonstrate the applicability of finite-size scaling as a tool in the experimental search for the critical endpoint. Using data from RHIC and SPS and assuming finite-size scaling, we find that RHIC data from 200 GeV down to 19.6 GeV is only consistent with a critical point at μ\gtrsim 510 MeV. We also present predictions for the fluctuations at lower energies currently being …
We present a comparison of inclusive photon elliptic flow parameter (v_{2}) measured at RHIC and SPS high energy heavy-ion collision experiments to calculations done using the AMPT and UrQMD models. The new results discussed includes the comparison of the model calculations of photon v_{2} to corresponding measurements at the forward rapidities. We observe that the AMPT model which includes partonic interactions and quark coalescence as a mechanism of hadronization is in good agreement with the measurements even at forward rapidities (2.3 < η< 3.9) at RHIC as was previously observed for measur…
Recent extensive data from the beam energy scan of the STAR collaboration at BNL-RHIC provide the basis for a detailed update for the universal behavior of the strangeness suppression factor gamma_s as function of the initial entropy density, as proposed in our recent paper [1]. [1] P. Castorina, S. Plumari and H. Satz, Int. J. Mod. Phys. E26 (2017) 1750081 (arXiv:1709.02706)
We investigate the measurement of the sixth order cumulant and its ratio to the second order cumulant ($C_6/C_2$) in relativistic heavy-ion collisions. The influence of statistics and different methods of centrality bin width correction on $C_6/C_2$ of net-proton multiplicity distributions is demonstrated. There is no satisfactory method to extract $C_6/C_2$ with the current statistics recorded at lower energies by STAR at RHIC. With statistics comparable to the expected statistics at the planned future RHIC Beam Energy Scan II (BES II), no energy dependence of $C_6/C_2$ is observed in central…
We present various order moments (Variance ($σ^2$), Skewness($S$), Kurtosis($κ$)) of net-proton multiplicity distributions in Au+Au collisions from the first phase of RHIC beam energy scan ({\sNN}=7.7$-$200 GeV). The measurements are carried out by the STAR detector at mid-rapidity ($|y|<0.5$) and within transverse momentum range $0.4<p_{T}<0.8$ {\gevc}. The product of moments ({\SD} and \KV) are predicted to be sensitive to the correlation length and connected to ratios of baryon number susceptibility. We observe deviations below Poisson expectations in the most central collisions for all of …
Collisions of light and heavy nuclei in relativistic heavy-ion collisions have been shown to be sensitive to nuclear structure. With a proposed $^{16}\mathrm{O}^{16}\mathrm{O}$ run at the LHC and RHIC we study the potential for finding $α$ clustering in $^{16}$O. Here we use the state-of-the-art iEBE-VISHNU package with $^{16}$O nucleonic configurations from {\rm ab initio} nuclear lattice simulations. This setup was tuned using a Bayesian analysis on pPb and PbPb systems. We find that the $^{16}\mathrm{O}^{16}\mathrm{O}$ system always begins far from equilibrium and that at LHC and RHIC it ap…
We perform a global QCD analysis of unpolarized parton distributions within a Bayesian Monte Carlo framework, including the new $W$-lepton production data from the STAR Collaboration at RHIC and Drell-Yan di-muon data from the SeaQuest experiment at Fermilab. We assess the impact of these two new measurements on the light antiquark sea in the proton, and the $\bar{d}-\bar{u}$ asymmetry in particular. The SeaQuest data are found to significantly reduce the uncertainty on the $\bar{d}/\bar{u}$ ratio at large parton momentum fractions $x$, strongly favoring an enhanced $\bar{d}$ sea up to $x \app…
Baryon fluctuation signatures of the onset of deconfinement
Jan Kochanowski University（扬·科哈诺夫斯基大学）；Bogolyubov Institute for Theoretical Physics（博戈柳博夫理论物理研究所）；GSI Helmholtzzentrum für Schwerionenforschung（德国重离子研究中心）
