Smallest drop of QGP: Thermodynamic properties in p-Pb collisions

The extreme conditions of temperature and density produced in ultrarelativistic collisions of heavy nuclei facilitate the formation of the most fundamental fluid in the universe, the deconfined phase of Quantum Chromodynamics called quark-gluon plasma. Despite the extensive experimental evidence collected over the past decade of its production in colliding systems such as Au-Au and Pb-Pb, establishing quark-gluon plasma formation in the collision of smaller systems, such as p-Pb, remains an open question. In this study, we describe the evolution of matter formed in p-Pb collisions at 5.02 TeV using a state-of-the-art hybrid model based on viscous relativistic hydrodynamics. We investigate the thermodynamic properties of the medium and final state observables. Our findings are compared with experimental data and first-principles calculations derived from lattice quantum chromodynamics. The results support the formation of a collective phase of strongly interacting matter in high-multiplicity p-Pb collisions.

[1]  Samir R Das,et al.  Multiplicity dependence of charged-particle production in pp, p–Pb, Xe–Xe and Pb–Pb collisions at the LHC , 2022, Physics Letters B.

[2]  A. Soloviev.  Hydrodynamic attractors in heavy ion collisions: a review , 2021, The European Physical Journal C.

[3]  G. Giacalone.  A matter of shape: seeing the deformation of atomic nuclei at high-energy colliders , 2021, 2101.00168.

[4]  R. Snellings,et al.  Bayesian analysis of heavy ion collisions with the heavy ion computational framework Trajectum , 2020, Physical Review C.

[5]  M. Luzum,et al.  Thermodynamics of hot strong-interaction matter from ultrarelativistic nuclear collisions , 2020 .

[6]  S. Bass,et al.  Bayesian calibration of a hybrid nuclear collision model using p−Pb and Pb-Pb data at energies available at the CERN Large Hadron Collider , 2020 .

[7]  M. Luzum,et al.  Effects of initial state fluctuations on the mean transverse momentum , 2020, 2002.07008.

[8]  K. Reygers,et al.  Entropy production in pp and Pb-Pb collisions at energies available at the CERN Large Hadron Collider , 2019, Physical Review C.

[9]  A. Bazavov,et al.  Chiral crossover in QCD at zero and non-zero chemical potentials , 2018, Physics Letters B.

[10]  Jr.,et al.  Creation of quark–gluon plasma droplets with three distinct geometries , 2018, Nature Physics.

[11]  J. Nagle,et al.  Small System Collectivity in Relativistic Hadronic and Nuclear Collisions , 2018, Annual Review of Nuclear and Particle Science.

[12]  M. Spiropulu,et al.  Charged-particle nuclear modification factors in PbPb and pPb collisions at √(s_N N) = 5.02 TeV , 2017 .

[13]  P. Romatschke,et al.  One fluid to rule them all: Viscous hydrodynamic description of event-by-event central p+p, p+Pb and Pb+Pb collisions at s = 5.02 TeV , 2017, 1701.07145.

[14]  M. Janik,et al.  An overview of experimental results from ultra-relativistic heavy-ion collisions at the CERN LHC: Bulk properties and dynamical evolution , 2016, 1702.07233.

[15]  P. Romatschke.  Do nuclear collisions create a locally equilibrated quark–gluon plasma? , 2016, 1609.02820.

[16]  S. M. Etesami,et al.  Evidence for collectivity in pp collisions at the LHC , 2016, Physics Letters B.

[17]  J. Thäder,et al.  Multiplicity and transverse momentum evolution of charge-dependent correlations in pp, p–Pb, and Pb–Pb collisions at the LHC , 2015, The European Physical Journal. C, Particles and Fields.

[18]  U. Heinz,et al.  Pre-equilibrium evolution effects on heavy-ion collision observables , 2015, 1504.02160.

[19]  P. Romatschke.  Light-heavy-ion collisions: a window into pre-equilibrium QCD dynamics? , 2015, 1502.04745.

[20]  M. Luzum,et al.  Effects of viscosity on the mapping of initial to final state in heavy ion collisions , 2014, 1411.2574.

[21]  P. Bożek,et al.  Hydrodynamic approach to p–Pb , 2014, 1401.2367.

[22]  J. Carlson,et al.  Exploiting intrinsic triangular geometry in relativistic (3)He+Au collisions to disentangle medium properties. , 2013, Physical review letters.

[23]  Z. Fodor,et al.  Full result for the QCD equation of state with 2+1 flavors , 2013, 1309.5258.

[24]  D. Rischke,et al.  Relative importance of second-order terms in relativistic dissipative fluid dynamics , 2013, 1308.0785.

[25]  Hale,et al.  Multiplicity dependence of the average transverse momentum in pp, p-Pb, and Pb-Pb collisions at the LHC , 2013, 1307.1094.

[26]  Atlas Collaboration.  Measurement with the ATLAS detector of multi-particle azimuthal correlations in p+Pb collisions at sqrt(s_NN)=5.02 TeV , 2013, 1303.2084.

[27]  R. Snellings,et al.  Collective Flow and Viscosity in Relativistic Heavy-Ion Collisions , 2013, 1301.2826.

[28]  D. Rischke,et al.  Derivation of transient relativistic fluid dynamics from the Boltzmann equation , 2012, 1202.4551.

[29]  B. Wyslouch,et al.  First Results from Pb+Pb Collisions at the LHC , 2012, 1202.3233.

[30]  D. Teaney,et al.  Triangularity and Dipole Asymmetry in Heavy Ion Collisions , 2010, 1010.1876.

[31]  S. Jeon,et al.  (3+1)D hydrodynamic simulation of relativistic heavy-ion collisions , 2010, 1004.1408.

[32]  S. Voloshin,et al.  Effect of flow fluctuations and nonflow on elliptic flow methods , 2009, 0906.3463.

[33]  A. Kisiel,et al.  Free-streaming approximation in early dynamics of relativistic heavy-ion collisions , 2008, 0812.3393.

[34]  Marcus Bleicher,et al.  Fully integrated transport approach to heavy ion reactions with an intermediate hydrodynamic stage , 2008, 0806.1695.

[35]  J. Ollitrault,et al.  Relativistic hydrodynamics for heavy-ion collisions , 2007, 0708.2433.

[36]  B. E. al.  The PHOBOS Perspective on Discoveries at RHIC , 2004, nucl-ex/0410022.

[37]  E. al.,et al.  Quark gluon plasma and color glass condensate at RHIC? The Perspective from the BRAHMS experiment , 2004, nucl-ex/0410020.

[38]  E. al.,et al.  Formation of dense partonic matter in relativistic nucleus–nucleus collisions at RHIC: Experimental evaluation by the PHENIX Collaboration , 2004, nucl-ex/0410003.

[39]  S. Bass,et al.  Microscopic models for ultrarelativistic heavy ion collisions , 1998, nucl-th/9803035.

[40]  Werner Israel,et al.  Transient relativistic thermodynamics and kinetic theory , 1979 .

[41]  W. Israel.  Nonstationary irreversible thermodynamics: A Causal relativistic theory , 1976 .

[42]  Giorgio Parisi,et al.  Exponential Hadronic Spectrum and Quark Liberation , 1975 .

[43]  J. Collins,et al.  Superdense Matter: Neutrons Or Asymptotically Free Quarks? , 1975 .

[44]  Fred Cooper,et al.  Single-particle distribution in the hydrodynamic and statistical thermodynamic models of multiparticle production , 1974 .

[45]  H. M. Spinka,et al.  Experimental and Theoretical Challenges in the Search for the Quark Gluon Plasma: The STAR Collaboration’s Critical Assessment of the Evidence from RHIC Collisions , 2005 .