Open Charm Measurements at CERN SPS Energies with the New Vertex Detector of the NA61/SHINE Experiment: Status and Plans

Anastasia Merzlaya

doi:10.3390/universe5010014

Abstract

The study of open charm meson production provides an efficient tool for detailed investigations of the properties of hot and dense matter formed in nucleus-nucleus collisions. The interpretation of the existing data from the CERN Super Proton Synchrotron (SPS) suffers from a lack of knowledge about the total charm production rate. To overcome this limitation, the heavy-ion program of the NA61/SHINE experiment at the CERN SPS has been upgraded to allow for precise measurements of particles with a short lifetime. A new vertex detector (Small Acceptance version of the Vertex Detector (SAVD)) was constructed to meet the challenges of open charm measurements in nucleus-nucleus collisions. The first exploratory data taking of Pb + Pb collisions at 150A GeV/c with the SAVD was performed in 2016, and a D 0 signal was extracted in its D 0 → π + + K − decay channel. This was the first, direct observation of open charm in nucleus-nucleus collisions at the SPS energies. Furthermore, the future plans of open charm measurements in the NA61/SHINE experiment related to the upgraded version of the Vertex Detector are discussed.

Highlights

One of the important issues related to relativistic heavy-ion collisions is the mechanism of charm production
A good estimate of hcci can be obtained by measuring production yields of D0, D +, and their antiparticles because these mesons carry about 85% of the total produced charm (this value is predicted by the Parton Hadron String Dynamics (PHSD) model [3])
The Small Acceptance version of the Vertex Detector (SAVD) was installed in the NA61/SHINE experiment in 2016 to allow open charm measurements

Summary

Introduction

One of the important issues related to relativistic heavy-ion collisions is the mechanism of charm production. At very high energy collisions, the multiplicities of ccpairs are high, which may lead to the secondary formation of J/ψ mesons, complicating the study of the in-medium effect on J/ψ meson production; The RHIC Beam Energy Scan (BES) collider program ( sNN = 7.7 − 39 GeV): measurement is not considered in the current program; this may likely be due to difficulties related to collider geometry and kinematics, as well as the low charm production cross-section [17,18]; The RHIC BES fixed-target program ( sNN = 3 − 7.7 GeV): not considered in the current program [19]; The Nuclotron-based Ion Collider fAcility (NICA) ( sNN < 11 GeV): measurements during. The SPS Heavy Ion and Neutrino Experiment (NA61/SHINE) [23] at CERN was designed for studies of the properties of the onset of deconfinement and the search for the critical point of strongly-interacting matter These goals are being pursued by investigating p + p, p + A, and A + A collisions at different beam momenta from 13A–158A GeV/c for ions and up to 400 GeV/c for protons.

Data Reconstruction in the Vertex Detector

Open Charm Measurements with the SAVD

Proposed Open Charm Measurements after CERN Long Shutdown 2

Findings

Summary