Energy dependence of polarized γγ → e⁺e⁻ in peripheral Au+Au collisions at RHIC
- We report the differential yields at mid-rapidity of the Breit-Wheeler process (γγ→e+e−) in peripheral Au+Au collisions at sNN−−−√= 54.4 GeV and 200 GeV with the STAR experiment at RHIC, as a function of energy sNN−−−√, e+e− transverse momentum pT, p2T, invariant mass Mee and azimuthal angle. In the invariant mass range of 0.4 < Mee < 2.6 GeV/c2 at low transverse momentum (pT <0.15 GeV/c), the yields increase while the pair ⟨p2T⟩−−−−√ decreases with increasing sNN−−−√, a feature is correctly predicted by the QED calculation. The energy dependencies of the measured quantities are sensitive to the nuclear form factor, infrared divergence and photon polarization. The data are compiled and used to extract the charge radius of the Au nucleus.
| URN: | urn:nbn:de:hebis:30:3-864710 |
|---|---|
| URL: | https://arxiv.org/abs/2407.14821v1 |
| DOI: | https://doi.org/10.48550/arXiv.2407.14821 |
| ArXiv Id: | http://arxiv.org/abs/2407.14821v1 |
| Parent Title (English): | arXiv |
| Publisher: | arXiv |
| Document Type: | Preprint |
| Language: | English |
| Date of Publication (online): | 2024/07/20 |
| Date of first Publication: | 2024/07/20 |
| Publishing Institution: | Universitätsbibliothek Johann Christian Senckenberg |
| Creating Corporation: | STAR Collaboration |
| Release Date: | 2024/08/12 |
| Issue: | 2407.14821v1 |
| Edition: | Version 1 |
| Page Number: | 23 |
| Institutes: | Wissenschaftliche Zentren und koordinierte Programme / Frankfurt Institute for Advanced Studies (FIAS) |
| Dewey Decimal Classification: | 5 Naturwissenschaften und Mathematik / 53 Physik / 530 Physik |
| Sammlungen: | Universitätspublikationen |
| Licence (German): |  Creative Commons - CC BY-NC-ND - Namensnennung - Nicht kommerziell - Keine Bearbeitungen 4.0 International |
