Initial-State Quantum Fluctuations in the Little Bang

Gelis, François; Schenke, Bjoern

doi:10.1146/annurev-nucl-102115-044651

Cited by 24 publications

(19 citation statements)

References 159 publications

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“…One also has to consider that since the area is small, the modification of the initial geometry should become more relevant that in the case of AA collisions. The importance of the initial state geometry in such systems including the elliptic geometry and its eccentricity have been recently studied in references [30,31].…”

Section: Introductionmentioning

confidence: 99%

String percolation threshold for elliptically bounded systems

Ramírez¹,

Téllez²,

Bautista³

2017

Physica A: Statistical Mechanics and its Applications

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It has been shown that a hot and dense deconfined nuclear matter state produced in ultra-relativistic heavy-ion collisions, can be quantitatively described by the String Percolation phenomenological model. The model address the phase transition in terms of the two-dimensional continuum percolation theory over strings, which are schematic representations of the fundamental interactions among the partons of the colliding nuclei in the initial state. In this work, we present an extension of the critical string density results including the eccentricity dependence on the initial state geometry focus on small string number with different density profile, small deviations from the different profile densities are found. The percolation threshold shows consistency with the thermodynamic limit for the uniform density profile with a large number of strings in the case of circular boundary system. A significant dependence on the eccentricity for a small number of strings compared to high occupancy systems is exhibited, the implications may become relevant in hadron-hadron or hadron-nucleus collision systems.

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Section: Introductionmentioning

confidence: 99%

String percolation threshold for elliptically bounded systems

Ramírez¹,

Téllez²,

Bautista³

2017

Physica A: Statistical Mechanics and its Applications

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“…It was predicted in the super(over) cooling scenario [48,49]. The extra pions at low p T may appear due to fast hadronization of the gluon condensate [50,51], glueballs [52], or Color Glass Condensate [53,54], forming transient Bose-Einstein condensate of pions [55]. The time needed to form such a condensate at the LHC is lower than at RHIC, and is just t ∼ 0.1 − 0.2 fm/c [56,57].…”

Section: Introductionmentioning

confidence: 99%

Fluctuations as a test of chemical nonequilibrium at energies available at the CERN Large Hadron Collider

Begun

2016

Phys. Rev. C

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It is shown that large chemical potential leads to the significant increase of multiplicity fluctuations for bosons, and makes the fluctuations infinite in the case of Bose-Einstein condensation. It allows to distinguish between the models that explain the anomalous proton to pion ratio and the low transverse momentum enhancement of pion spectra in Pb+Pb collisions at the LHC within chemical equilibrium or non-equilibrium models. The effects of resonance decays, finite size of the system, requirements to the event statistics, different momentum cuts, and limited detector acceptance are considered. The obtained results show the possibility to observe a substantial increase of the normalized kurtosis for positively or negatively charged pions in the case of non-equilibrium or partial pion condensation using currently measured data.

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“…The initial gluon distributions [14,15] from the IP-Glasma model are anisotropic in momentum space [8,16,17], thus contain the intrinsic momentum space correlations of the color glass condensate (CGC) picture [18,19]. Final state interactions mediated by perturbative quantum chromo dynamic (pQCD) cross sections are then simulated microscopically in BAMPS.…”

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confidence: 99%

Importance of initial and final state effects for azimuthal correlations in p+Pb collisions

et al. 2017

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We investigate the relative importance of initial and final state effects on azimuthal correlations of gluons in low and high multiplicity p+Pb collisions. To achieve this, we couple Yang-Mills dynamics of pre-equilibrium gluon fields (IP-GLASMA) to a perturbative QCD based parton cascade for the final state evolution (BAMPS) on an event-by-event basis. We find that signatures of both the initial state correlations and final state interactions are seen in azimuthal correlation observables, such as v2 {2P C} (pT ), their strength depending on the event multiplicity and transverse momentum. Initial state correlations dominate v2 {2P C} (pT ) in low multiplicity events for transverse momenta pT > 2 GeV. While final state interactions are dominant in high multiplicity events, initial state correlations affect v2 {2P C} (pT ) for pT > 2 GeV as well as the pT integrated v2 {2P C}.Introduction. The measured azimuthal momentum anisotropies of produced particles in heavy ion collisions are well described in the framework of event-by-event hydrodynamics. In this picture a fluctuating initial geometry, dominated by fluctuating nucleon positions in the incoming nuclei, is converted into anisotropic momentum space distributions by the pressure driven final state evolution. Hydrodynamic simulations agree well with a wide range of experimental observables from the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory and the Large Hadron Collider (LHC) at CERN [1][2][3][4].Measurements in smaller collision systems such as p+p and p+A [5], in particular those of anisotropies in multiparticle correlation functions, have shown very similar features as those in heavy ion collisions. While calculations within the hydrodynamic framework have been quite successful in describing observables in these small collision systems, alternative explanations relying entirely on intrinsic momentum correlations of the produced particles can also reproduce many features of the experimental data. This includes two and more particle azimuthal correlations and their p T dependence [5][6][7] and mass splitting of identified particle v n [8]. Apart from the existence of alternative explanations, the applicability of hydrodynamics becomes increasingly doubtful as the system size decreases and gradients increase. Some recent studies argue that hydrodynamics should be applicable in systems of sizes down to ∼ 0.15 fm [9], but off-equilibrium corrections to particle distribution functions for momenta p T 0.5 GeV can be significant [10], which limits at least the quantitative reliability of the framework.So far all calculations of multi-particle correlations in small collision systems have studied either only intrinsic momentum correlations or purely final state driven ef-

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Initial-State Quantum Fluctuations in the Little Bang

Cited by 24 publications

References 159 publications

String percolation threshold for elliptically bounded systems

String percolation threshold for elliptically bounded systems

Fluctuations as a test of chemical nonequilibrium at energies available at the CERN Large Hadron Collider

Importance of initial and final state effects for azimuthal correlations in p+Pb collisions

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