arXiv subjects

W. Zha

Publications and source records attributed to W. Zha.

5 recordsLinked to original sources

arXiv2022

Snowmass 2021 Scintillating Bubble Chambers: Liquid-noble Bubble Chambers for Dark Matter and CE$ν$NS Detection

The Scintillating Bubble Chamber (SBC) Collaboration is developing liquid-noble bubble chambers for the quasi-background-free detection of low-mass (GeV-scale) dark matter and coherent scattering of low-energy (MeV-scale) neutrinos (CE$ν$NS). The first physics-scale demonstrator of this technique, a 10-kg liquid argon bubble chamber dubbed SBC-LAr10, is now being commissioned at Fermilab. This device will calibrate the background discrimination power and sensitivity of superheated argon to nuclear recoils at energies down to 100 eV. A second functionally-identical detector with a focus on radiopure construction is being built for SBC's first dark matter search at SNOLAB. The projected spin-independent sensitivity of this search is approximately $10^{-43}$ cm$^2$ at 1 GeV$/c^2$ dark matter particle mass. The scalability and background discrimination power of the liquid-noble bubble chamber make this technique a compelling candidate for future dark matter searches to the solar neutrino fog at 1 GeV$/c^2$ particle mass (requiring a $\sim$ton-year exposure with non-neutrino backgrounds sub-dominant to the solar CE$ν$NS signal) and for high-statistics CE$ν$NS studies at nuclear reactors.

physics.ins-det↗

arXiv2022

Detector Requirements and Simulation Results for the EIC Exclusive, Diffractive and Tagging Physics Program using the ECCE Detector Concept

This article presents a collection of simulation studies using the ECCE detector concept in the context of the EIC's exclusive, diffractive, and tagging physics program, which aims to further explore the rich quark-gluon structure of nucleons and nuclei. To successfully execute the program, ECCE proposed to utilize the detecter system close to the beamline to ensure exclusivity and tag ion beam/fragments for a particular reaction of interest. Preliminary studies confirmed the proposed technology and design satisfy the requirements. The projected physics impact results are based on the projected detector performance from the simulation at 10 or 100 fb^-1 of integrated luminosity. Additionally, a few insights on the potential 2nd Interaction Region can (IR) were also documented which could serve as a guidepost for the future development of a second EIC detector.

physics.ins-det↗

arXiv2018

Coherent lepton pair production in hadronic heavy ion collisions

Recently, significant enhancements of $e^{+} e^{-}$ pair production at very low transverse momentum ($p_{T} < 0.15$ GeV/c) were observed by the STAR collaboration in peripheral hadronic A+A collisions. This excesses can not be described by the QGP thermal radiation and $ρ$ in-medium broadening calculations. This is a sign of coherent photon-photon interactions, which were conventionally studied only in ultra-peripheral collisions. In this article, we present calculations of lepton pair ($e^{+}e^{-}$ and $μ^{+}μ^{-}$) production from coherent photon-photon interactions in hadronic A+A collisions at RHIC and LHC energies within the STAR and ALICE acceptance.

hep-ph↗

arXiv2017

Coherent J/$ψ$ photoproduction in hadronic heavy-ion collisions

A significant excess of J/$ψ$ yield at very low transverse momentum ($p_T < 0.3$ GeV/c) was observed by the ALICE and STAR collaborations in peripheral A+A collisions, which points to evidence of coherent photoproduction of J/$ψ$ in violent hadronic interactions. Theoretically, the photoproduction of J$/ψ$ in hadronic collisions raises questions about how spectator and non-spectator nucleons participate in the coherent reaction. For the first time, we argue that the strong interactions in the overlapping region of incoming nuclei may disturb the coherent production, leaving room for different coupling assumptions. Furthermore, first considerations of the destructive interference between photoproduction on ions moving in opposite directions in hadronic heavy-ion collisions are included. This letter presents calculations of J$/ψ$ production from coherent photon-nucleus ($γ+ A \rightarrow \text{J}/ψ+ A$) interactions in hadronic A+A collisions at RHIC and LHC energies with both nucleus and spectator coupling hypotheses. The coherent J/$ψ$ yield as a function of centrality and differential distributions as a function of transverse momentum, azimuthal angle and rapidity in different centrality bins are shown and found to be significantly different for different coupling scenarios, calling for future experimental measurements.

nucl-th↗

arXiv2016

Muon Identification with Muon Telescope Detector at the STAR Experiment

Muon Telescope Detector (MTD) is a newly installed detector in the STAR experiment. It provides an excellent opportunity to study heavy quarkonium physics using the dimuon channel in heavy ion collisions. In this paper, we report the muon identification performance for the MTD using proton-proton collision at $\sqrt{s}$ = 500 GeV with various methods. The result using the Likelihood Ratio method shows that the muon identification efficiency can reach to $\sim$90% for muons with transverse momentum greater than 3 GeV/c and the significance of J/$ψ$ signal is improved by $\sim$40% compared to using the basic selection.

physics.ins-det↗