Muonic atoms at RHIC

TL;DR

This paper reports the search for muonic atoms at RHIC using the STAR experiment, identifying potential signatures through invariant mass peaks and correlation functions, and analyzing muon origins.

Contribution

It presents the first experimental search for muonic atoms at RHIC, utilizing correlation functions to identify possible atom ionization signatures and measure direct muon fractions.

Findings

Peaks at expected muonic atom masses in invariant mass distributions

Correlation functions suggest simultaneous emission of hadrons and muons

Fraction of direct muons quantified from pion-muon correlations

Abstract

We report the search results of muonic atoms from the STAR experiment at RHIC. The invariant mass distributions of hadron-muon pairs show peaks at the expected atom masses. Two particle correlation functions indicate the hadrons and muons that are close in phase space are emitted at the same space time point, which is a possible signature of muonic atom ionization at the beam pipe. The pion-muon correlation functions are further decomposed into two contributions, and the fraction of direct muons is obtained.