2019/02/28 by Gopolang Mohlabeng · 1 citation
Physics and Astronomy · #hep-ph #astro-ph.CO #hep-ex
paper · pdf · doi:10.1103/physrevd.99.115001
published as Phys. Rev. D 99, 115001 (2019) · 5 pages + references, 3 figures
arxiv created 2019/06/07 · arxiv updated 2019/06/11
A massive U(1)′ gauge boson known as a "dark photon" or A′, has long been proposed as a potential explanation for the discrepancy observed between the experimental measurement and theoretical determination of the anomalous magnetic moment of the muon, (gμ - 2) anomaly. Recently, experimental results have excluded this possibility for a dark photon exhibiting exclusively visible or invisible decays. In this work, we revisit this idea and consider a model where A′ couples inelastically to dark matter and an excited dark sector state, leading to a more exotic decay topology we refer to as a semi-visible decay. We show that for large mass splittings between the dark sector states this decay mode is enhanced, weakening the previous invisibly decaying dark photon bounds. As a consequence, A′ resolves the gμ - 2 anomaly 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 gμ - 2 anomaly.