http://arxiv.org/abs/1902.05075
A massive $U(1)^{\prime}$ gauge boson, “dark photon” or $A^{\prime}$, has long been proposed as a potential explanation of the muon $g-2$ anomaly ($g_{\mu} – 2$). However, recent experimental results have excluded this possibility for a dark photon exhibiting exclusively visible or invisible decays. In this work we consider an inelastic dark matter (iDM) model where $A^{\prime}$ couples directly to dark matter and an excited dark sector state, leading to a more exotic decay topology, which we refer to as a semi-visible decay. For large mass splittings between the dark sector states this decay mode is enhanced, weakening the invisibly decaying dark photon bounds. As a consequence, $A^{\prime}$ can account for the discrepancy between the $g_{\mu} – 2$ theory calculation and experimental measurement, in a region of parameter space the thermal dark matter component of the Universe is readily explained. Interestingly, it is possible that the semi-visible events we discuss may have been vetoed by experiments searching for invisible dark photon decays. A re-analysis of the data and future searches may be crucial in uncovering this exotic decay mode or closing the window on the dark photon explanation of the $g_{\mu} – 2$ anomaly.
G. Mohlabeng
Fri, 15 Feb 19
6/48
Comments: 5 pages + references, 3 figures
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