Revisiting the Dark Photon Explanation of the Muon g-2 Anomaly. (arXiv:1902.05075v1 [hep-ph])
<a href="http://arxiv.org/find/hep-ph/1/au:+Mohlabeng_G/0/1/0/all/0/1">Gopolang Mohlabeng</a>
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.
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.
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