Speaker
Description
One of the greatest unsolved mysteries of modern physics is the observation of invisible yet gravitationally attractive dark matter. The dark photon $A^\prime$ is a proposed new U(1) gauge boson that offers a unique vector portal between the Standard Model and the dark sector.
This poster presents a new, ongoing search at BESIII for the creation and visible decay of a massive dark photon via the initial state radiation process $e^+e^- \to A^\prime \gamma_{ISR} \to l^+l^- \gamma_{ISR}, (l=e,\mu)$. This analysis uses the newly acquired BESIII data on the $\psi(3770)$ resonance with a luminosity of $(20.275 \pm 0.077) \,\rm fb^{-1}$, currently the world’s largest data set at $\sqrt{s}= 3.773 \,\rm GeV$. The final state $l^+l^-$ invariant mass spectra are scanned to search for a narrow dark photon resonance atop the irreducible QED background.
| Collaboration | BESIII |
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