Quark Matter 2025

Session

Parallel session 33

9 Apr 2025, 11:10

Goethe University Frankfurt, Campus Westend, Theodor-W.-Adorno-Platz 1, 60629 Frankfurt am Main, Germany

Conveners

Parallel session 33: Electromagnetic probes II

• Alberica Toia (Goethe University Frankfurt (DE))

1120. Direct photon production from small to large collision systems with ALICE

Joshua Leon Konig (Goethe University Frankfurt (DE))

09/04/2025, 11:10

Electromagnetic probes

Oral

Electromagnetic probes are a unique tool for studying the space-time evolution of the hot and dense matter created in ultra-relativistic heavy-ion collisions. Photons and dielectron pairs are emitted during the entire evolution of the medium created in such collisions, providing access to direct-photon production that includes thermal radiation from the early hot stages of the collision. The...

956. Early EM fields in PbPb collisions via their effect on dimuon decays of Z bosons and top quark production with CMS

Jose Francisco Gonzalez (University of California Davis (US))

09/04/2025, 11:30

Electromagnetic probes

Oral

We present a selection of recent measurements of electromagnetic probes conducted by CMS to probe initial-state aspects of the heavy ion collision. The Z boson has a very short lifetime and can decay to dimuon final states that can be precisely measured. These properties make it a valuable tool for studying the initial state of heavy ion collisions. It has been proposed that the momentum of...

918. Thermal dielectron measurements with the STAR experiment

Jiaxuan Luo

09/04/2025, 11:50

Electromagnetic probes

Oral

Thermal dielectrons, which are produced throughout the entire evolution of relativistic heavy-ion collisions and are not involved in strong interactions, are suggested as the ideal probes of the hot and dense medium. By measuring the mass spectra of thermal dielectrons, one can extract the average temperature of the medium in different stages.Since the thermal dielectron emission rate is...

220. Electromagnetic tomography of Quark-Gluon Plasma at finite baryon densities

Xiang-Yu Wu (McGill University)

09/04/2025, 12:10

Electromagnetic probes

Oral

Relativistic heavy-ion collisions at the RHIC Beam Energy Scan program and SPS energies probe the QCD phase diagram at finite baryon densities. Precise photon and dilepton measurements serve as unique tomographic probes for the properties of hot nuclear matter. In this work, we study the electromagnetic radiation from relativistic heavy-ion collisions from 7.7 to 200 GeV. The dynamical...

181. Dilepton polarization as a signature of plasma anisotropy

Maurice Coquet (Centre National de la Recherche Scientifique (FR))

09/04/2025, 12:30

Electromagnetic probes

Oral

We propose the angular distribution of lepton pairs produced in ultrarelativistic heavy-ion collisions as a probe of thermalization of the quark-gluon plasma. We focus on dileptons with invariant masses large enough that they are produced through quark-antiquark annihilation in the early stages of the collision. The angular distribution of the lepton in the rest frame of the pair then reflects...