Student Research Projects




The Heavy Photon Search (HPS) is a new experiment at Jefferson Laboratory to search for heavy photons, a particle predicted by dark matter and dark energy extensions to the Standard Model of particle physics, in the mass range of 20 MeV/c2 to 1000 MeV/c2 . The experiment also has the potential to discover true muonium, a bound state of a muon and an antimuon that is predicted to exist, but has never been observed. The true muonium atom should be produced by an electron beam incident on a target, such as the tungsten target used in the HPS experiment. Similar to the decay of the heavy photon, a triplet state of true muonium will decay to an electron-positron pair, allowing it to be detected in the same way. Since the mass of the atom will be about twice the mass of a muon, or approximately 211 MeV/c2 , and the decay length is expected to be on the order of centimeters, a precise search window can be specified. Simulations of this experiment were performed and an analysis was carried out to calculate how well we can expect to observe true muonium. Based on this analysis, the Heavy Photon Search will have a reconstruction efficiency of 16-20 %, and will be able to observe and fully reconstruct approximately 35 events after a month of running with a 6.6 MeV electron beam. As a result, the true muonium signal is expected to be statistically significant above the background signal.

Date of Publication or Presentation

Spring 2014

Project Type

Undergraduate Research Project

College or School


First Advisor

Maurik Holtrop

Included in

Nuclear Commons