"Evidence for a Photophobic 5th force?" by Tim Tait (UC Irvine)

Monday, May 23, 2016 - 3:00pm to 4:00pm
TEPAPP Seminars

Theory of Elementary Particles, Astroparticle Physics, and Phenomenology (TEPAPP) Seminar

Physics & Astronomy Building (PAB) Room 4-330
Monday, May 23, 2016

Guest Speaker: Tim Tait (UC Irvine)

Talk Title: "Evidence for a Photophobic 5th force?"


Recently a 6.8σ anomaly has been reported in the opening angle and invariant mass distributions of e+e− pairs produced in 8Be nuclear transitions. The data are explained by a 17 MeV vector gauge boson X that is produced in the decay of an excited state to the ground state, 8Be∗ → 8BeX, and then decays through X→e+e−. The X boson mediates a fifth force with a characteristic range of 12 fm and has milli-charged couplings to up and down quarks and electrons, and a proton coupling that is suppressed relative to neutrons. The photophobic X boson may also alleviate the current 3.6σ discrepancy between the predicted and measured values of the muon's anomalous magnetic moment. I will discuss the experimental results concerning the nuclear transition, the details of a particle physics model which can hope to explain it while satisfying other constraints, and future experiments which can help shed light on the situation.

Event Attachments: 
PAB 4-330