Dilepton production from moaton quasiparticles

TL;DR

This paper explores how a moat regime in the QCD phase diagram, characterized by moatons with minimal energy at nonzero momentum, can lead to enhanced dilepton production, serving as an experimental signature.

Contribution

It identifies a specific operator at dimension six that enhances dilepton production near the moat threshold, linking theoretical QCD features to observable signals.

Findings

Enhanced dilepton production near moat threshold due to scalar-photon coupling

Identification of a unique gauge-invariant operator contributing to dilepton signals

Proposal of dilepton enhancement as an experimental signature of moatons in QCD

Abstract

The phase diagram of QCD may contain a moat regime in a large region of temperature $T$ and chemical potential $\mu\neq0$. A moat regime is characterized by quasiparticle moatons (pions) whose energy is minimal at nonzero spatial momentum. At $\mu\neq 0$, higher mass dimension operators play a critical role in a moat regime. At dimension six, there are nine possible gauge invariant couplings between scalars and photons. For back-to-back dilepton production, only one operator contributes, which significantly enhances production near a moat threshold. This enhancement is an experimental signature of moatons.