Speaker
Description
Ultraperipheral (UPC) lead-lead collisions produce very large photon fluxes, allowing for the study of fundamental quantum-mechanical processes and serving as a very good probe for physics beyond the standard model (BSM). In this talk, measurements of the light-by-light scattering (LbL, $\gamma\gamma\to\gamma\gamma$) and the Breit--Wheeler (B--W, $\gamma\gamma\to\mathrm{e}^+\mathrm{e}^-$) processes are reported in UPC at 5.02 TeV using the 2018 CMS lead-lead data sample of $1.65~\mathrm{nb}^{-1}$. Limits on the production of axion-like particles coupling to photons are set over the mass range $m_\mathrm{a} = 5$--100 GeV, including the most stringent limits in 5--10 GeV. We will also report the latest measurements of the anomalous magnetic moment of the $\tau$ lepton using UPC PbPb collisions recorded by the CMS experiment.
| Track type | Collider and BSM Physics |
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