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Investigating the Critical Point in Quantum Chromodynamics
Researchers are actively exploring the potential existence of a critical point within the Quantum Chromodynamics (QCD) phase diagram, which is essential for understanding how the strong force interacts with quarks and antiquarks to create protons, neutrons, and a variety of other particles, collectively known as hadrons.
This critical point is comparable to the phase transition endpoint seen in the transformation of water from liquid to gas. It is characterized by observable changes, particularly in the number of particles generated during collisions in particle accelerators.
To effectively model these observations, an extension to the conventional understanding of liquid and gas behavior is necessary. Researchers have introduced a new algorithm for simulating a critical fluid, as detailed in a recent study published in Physical Review Letters, which outlines their simulation approach.
Detecting critical fluctuations during heavy ion collisions would represent a groundbreaking achievement, marking the first direct evidence of a phase transition between the quark-gluon plasma and hadronic matter, the state in which quarks and gluons are bound within hadrons.
In order to interpret the findings from these experiments, a novel theoretical framework is required. This framework must account for fluid dynamics that incorporate fluctuations—variations in pressure, velocity, and other critical factors that characterize liquids and gases.
This significant effort seeks to establish connections between experimental data and theoretical concepts regarding temperature and pressure within quark-gluon matter. Future developments aim to enhance these methods, facilitating a deeper understanding of phase transitions.
The ongoing Beam Energy Scan (BES) program at the Relativistic Heavy Ion Collider (RHIC), managed by the Department of Energy at Brookhaven National Laboratory, investigates how fluctuations vary with energy in heavy ion collisions.
The primary objective of this research is to identify a possible critical point linked to the transition to quark-gluon plasma. An effective interpretation of BES results necessitates a fluid dynamic framework that fully integrates fluctuations in variables such as baryon density, entropy density, and fluid velocity.
In their latest research, scientists have developed and validated such a framework through simulations of a static fluid near the critical point. The next steps involve connecting their results with the dynamic expansion of the fireball produced in heavy ion collisions. This integration will aid in locating the critical point or further constraining its potential position.
More information: Chandrodoy Chattopadhyay et al., Simulations of Stochastic Fluid Dynamics near a Critical Point in the Phase Diagram, Physical Review Letters (2024). DOI: 10.1103/PhysRevLett.133.032301. On arXiv: DOI: 10.48550/arxiv.2403.10608
Citation: Simulating a critical point in quark gluon fluid (2024, September 24) retrieved from Phys.org.
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phys.org