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Title: Searching for the QCD critical point via the rapidity dependence of cumulants

Abstract

The search for a possible critical point in the QCD phase diagram is ongoing in heavy ion colli-sion 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 of the kurtosis (of the event-by-event distribution of the number of protons) on rapidity near mid-rapidity will change qualitatively if a critical point is passed in the scan. Furthermore, measuring the rapidity dependence of cumulant observables can enhance the prospect of discovering a critical point, in particular if it lies between two energies in the beam energy scan.

Authors:
 [1];  [2];  [1];  [1]
  1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
  2. Brookhaven National Lab. (BNL), Upton, NY (United States)
Publication Date:
Research Org.:
Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)
OSTI Identifier:
1485740
Alternate Identifier(s):
OSTI ID: 1489356
Report Number(s):
BNL-210834-2018-JAAM
Journal ID: ISSN 2469-9985; PRVCAN
Grant/Contract Number:  
SC0012704; SC0011090
Resource Type:
Published Article
Journal Name:
Physical Review C
Additional Journal Information:
Journal Volume: 98; Journal Issue: 6; Journal ID: ISSN 2469-9985
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS

Citation Formats

Brewer, Jasmine, Mukherjee, Swagato, Rajagopal, Krishna, and Yin, Yi. Searching for the QCD critical point via the rapidity dependence of cumulants. United States: N. p., 2018. Web. doi:10.1103/PhysRevC.98.061901.
Brewer, Jasmine, Mukherjee, Swagato, Rajagopal, Krishna, & Yin, Yi. Searching for the QCD critical point via the rapidity dependence of cumulants. United States. doi:10.1103/PhysRevC.98.061901.
Brewer, Jasmine, Mukherjee, Swagato, Rajagopal, Krishna, and Yin, Yi. Thu . "Searching for the QCD critical point via the rapidity dependence of cumulants". United States. doi:10.1103/PhysRevC.98.061901.
@article{osti_1485740,
title = {Searching for the QCD critical point via the rapidity dependence of cumulants},
author = {Brewer, Jasmine and Mukherjee, Swagato and Rajagopal, Krishna and Yin, Yi},
abstractNote = {The search for a possible critical point in the QCD phase diagram is ongoing in heavy ion colli-sion 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 of the kurtosis (of the event-by-event distribution of the number of protons) on rapidity near mid-rapidity will change qualitatively if a critical point is passed in the scan. Furthermore, measuring the rapidity dependence of cumulant observables can enhance the prospect of discovering a critical point, in particular if it lies between two energies in the beam energy scan.},
doi = {10.1103/PhysRevC.98.061901},
journal = {Physical Review C},
number = 6,
volume = 98,
place = {United States},
year = {2018},
month = {12}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record
DOI: 10.1103/PhysRevC.98.061901

Citation Metrics:
Cited by: 7 works
Citation information provided by
Web of Science

Figures / Tables:

FIG. 1 FIG. 1: In the left column we see that we have assumed the existence of a critical point (red dot) at (µ$c\atop{B}$ , T ) = (260, 160) MeV whose critical region, bounded by the contour where ξ = 1 fm, is colored red and blue. The colors denote themore » sign of ω4,σ, with ω4,σ > 0 in blue and ω4,σ < 0 in red. Different rows correspond to different assumptions for where on the phase diagram a heavy ion collision freezes out, cf. collisions with varying beam energy. The black circles show where freezeout occurs at mid-rapidity, from top to bottom with µB,0 = 200, 230, 240, 240 MeV. The black dashed curves show how the freezeout conditions change with increasing spacetime rapidity, with the circle, square, and triangle indicating freezeout at $ys$ = 0, 0.6, and 1.2, respectively. In the top three rows, we have chosen α = 50 MeV (see eq. 1) while for the bottom row we have chosen α = −50 MeV. The middle column shows how ω4,σ computed for a rapidity acceptance |y| < ymax depends on ymax. The right column shows how ω4,σ computed in a pair of bins with width ∆y = 0.4 centered at ±yc depends on yc. The results in the middle column sum over a wide range of rapidities (with |y| between 0 and ymax) which freezeout with a range of µB , meaning that features from the left column are more directly visible in the right column than in the middle. In both the center and right columns, the black dotted lines show ω4,σ with α = 0, i.e. what would have been obtained if µB = µB,0, denoted by the black circles in the left column, everywhere. The results shown in the right and middle column should not be taken as quantitative predictions since they depend on the many assumptions that we made for illustrative purposes; they are illustrative of qualitative features to be expected in the rapidity-dependence of cumulants if steps in beam energy take us past a critical point.« less

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Works referenced in this record:

Correlated stopping, proton clusters and higher order proton cumulants
journal, May 2017


Universal Off-Equilibrium Scaling of Critical Cumulants in the QCD Phase Diagram
journal, November 2016


Using higher moments of fluctuations and their ratios in the search for the QCD critical point
journal, October 2010

  • Athanasiou, Christiana; Rajagopal, Krishna; Stephanov, Misha
  • Physical Review D, Vol. 82, Issue 7
  • DOI: 10.1103/PhysRevD.82.074008

QCD Phase Diagram and the Critical Point
journal, January 2004


(3+1)-dimensional hydrodynamic expansion with a critical point from realistic initial conditions
journal, March 2008


Slowing out of equilibrium near the QCD critical point
journal, April 2000


Challenges in QCD matter physics --The scientific programme of the Compressed Baryonic Matter experiment at FAIR
journal, March 2017


STAR upgrade program and future physics
journal, September 2014


Proton-Number Fluctuation as a Signal of the QCD Critical End Point
journal, September 2003


Lattice results on QCD thermodynamics
journal, February 2002


Sign of Kurtosis near the QCD Critical Point
journal, July 2011


Color superconductivity and chiral symmetry restoration at non-zero baryon density and temperature
journal, January 1999


Exploring the QCD Phase Structure with Beam Energy Scan in Heavy-ion Collisions
journal, December 2016


Nuclear Stopping in A u + A u Collisions at s N N = 200 G e V
journal, August 2004


Event-by-event fluctuations in heavy ion collisions and the QCD critical point
journal, November 1999


QCD critical point and event-by-event fluctuations
journal, November 2011


Equation of state in ( 2 + 1 )-flavor QCD
journal, November 2014


Static and dynamic critical phenomena at a second order QCD phase transition
journal, July 1993


Dynamical evolution of critical fluctuations and its observation in heavy ion collisions
journal, June 2017


Heavy Ion Collisions: The Big Picture and the Big Questions
journal, October 2018


The Nuclotron-based Ion Collider Facility Project. The Physics Programme for the Multi-Purpose Detector
journal, May 2018


Thermodynamics of strong-interaction matter from lattice QCD
journal, October 2015

  • Ding, Heng-Tong; Karsch, Frithjof; Mukherjee, Swagato
  • International Journal of Modern Physics E, Vol. 24, Issue 10
  • DOI: 10.1142/S0218301315300076

Dynamical initial-state model for relativistic heavy-ion collisions
journal, February 2018


Comparison of chemical freeze-out criteria in heavy-ion collisions
journal, March 2006


Energy Dependence of Moments of Net-Proton Multiplicity Distributions at RHIC
journal, January 2014


Acceptance dependence of fluctuation measures near the QCD critical point
journal, March 2016


Rapidity dependence of proton cumulants and correlation functions
journal, November 2017


Cumulants and correlation functions versus the QCD phase diagram
journal, May 2017


Mapping the QCD phase diagram
journal, December 1999


Non-Gaussian Fluctuations near the QCD Critical Point
journal, January 2009


Real-time evolution of non-Gaussian cumulants in the QCD critical regime
journal, September 2015


Full result for the QCD equation of state with <mml:math altimg="si1.gif" overflow="scroll" xmlns:xocs="http://www.elsevier.com/xml/xocs/dtd" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.elsevier.com/xml/ja/dtd" xmlns:ja="http://www.elsevier.com/xml/ja/dtd" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:tb="http://www.elsevier.com/xml/common/table/dtd" xmlns:sb="http://www.elsevier.com/xml/common/struct-bib/dtd" xmlns:ce="http://www.elsevier.com/xml/common/dtd" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:cals="http://www.elsevier.com/xml/common/cals/dtd" xmlns:sa="http://www.elsevier.com/xml/common/struct-aff/dtd"><mml:mn>2</mml:mn><mml:mo>+</mml:mo><mml:mn>1</mml:mn></mml:math> flavors
journal, March 2014


QCD Phase Transition with Chiral Quarks and Physical Quark Masses
journal, August 2014


Phase diagram of QCD
journal, September 1998


The order of the quantum chromodynamics transition predicted by the standard model of particle physics
journal, October 2006


Signatures of the Tricritical Point in QCD
journal, November 1998


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