# Effects of enhanced bulk viscosity near the QCD critical point

## TL;DR

This paper explores how enhanced bulk viscosity near the QCD critical point affects particle distributions and dilepton spectra in heavy-ion collisions, providing potential experimental signatures of critical phenomena.

## Contribution

It introduces a relativistic hydrodynamic model incorporating bulk viscosity effects near the QCD critical point, highlighting observable modifications in collision outcomes.

## Key findings

- Rapidity distributions of charged particles are visibly altered near the critical point.
- Net baryon number distributions show significant changes.
- Dilepton invariant mass spectra may carry imprints of critical modifications.

## Abstract

Search for the conjectured QCD critical point is one of the major scientific goals for the Beam Energy Scan program at RHIC. The growth of the correlation length is a universal feature for systems near criticality, and bulk viscosity exhibits the strongest dependence on the correlation length. We investigate its effects using a relativistic hydrodynamic model to find that rapidity distributions of charged particles and net baryon number are visibly modified if the fireball passes through the vicinity of the QCD critical point on the phase diagram. We also discuss how critical modification of dilepton emission rate may leave imprints on invariant mass spectra.