Studies of Heavy Flavor Jets Using D0-Hadron Correlations in Azimuth and Pseudorapidity in Au Au Collisons at 200 GeV at the STAR Experiment

Alexander Jentsch

doi:10.3390/proceedings2019010034

Abstract

Heavy flavor (HF) quarks (charm, bottom) are important probes of the medium produced in relativistic heavy-ion collisions because they are formed in the early stage and propagate throughout the lifetime of the system. HF-meson spectra and azimuthal anisotropy ( v 2 ) measurements have been reported by experiments at RHIC and the LHC, and they suggest strong interactions of HF quarks with the medium. D 0 -hadron correlations on relative pseudorapidity and azimuth ( Δ η , Δ ϕ ) provide a method for disentangling correlation structures on ( Δ η , Δ ϕ )—allowing for separation of structures related to jets and bulk phenomena directly, with the D 0 serving as a proxy for a charm jet. In these proceedings, we present 2D D 0 -hadron angular correlations as a function of centrality in Au + Au collisions at s N N = 200 GeV. These data reveal a jet-like, peaked structure at ( Δ η , Δ ϕ ) = (0, 0) (near-side), and a Δ η -independent azimuthal harmonic modulation. Here, we focus on the evolution of the near-side peak’s yield and widths on ( Δ η , Δ ϕ ) as a function of centrality and compare them to results from light flavor correlations.

Highlights

Heavy flavor (HF) quarks are formed in the early stage of the collision between ultra-relativistic heavy ions
The analysis presented in these proceedings was carried out using around 900 million minimum-bias events collected by the STAR detector [5] at the Relativistic Heavy-Ion Collider (RHIC)
These proceedings present the first measurement of D0 -hadron correlations on (∆η, ∆φ) in heavy-ion collisions as a function of centrality

Summary

Introduction

Heavy flavor (HF) quarks are formed in the early stage of the collision between ultra-relativistic heavy ions. Measurements of the nuclear modification factor, R AA , by the STAR and ALICE collaborations show significant differences between light flavor (LF) mesons and HF mesons at low transverse momentum for mid- to very-central heavy-ion collisions [1,2,3]. The STAR collaboration has measured the D0 meson azimuthal anisotropy, v2 , and seen that it is consistent with the v2 of LF mesons as a function of transverse kinetic energy (m T − m0 ) at 10–40% centrality [4]. Proceedings 2019, 10, 34 evolution of the jet-like peak, as well as v2 , using a multi-parameter fit In these proceedings, we focus on correlations at small ∆φ (| ∆φ | < π/2; near-side or NS) and ∆η, which provide access to the charm jet interactions with the medium

D0 -Hadron Correlations

Results

Discussion and Conclusions