Rotation Projects in Heavy Photon Search

The Heavy Photon Search Group at SLAC is collaborating with physicists at Jefferson Lab (http://www.jlab.org/), Fermilab, UCSC, and U Oregon in two experiments aimed at discovering a hidden sector, or heavy, photon. Such a particle would have mass in the range 0.1 to 1.0 GeV, couple weakly to electrons, and decay to e+e-. It would be produced by electron bremstrahlung on a heavy target, and be identified as a narrow e+e- resonance. Its weak couplings to electrons account for its not yet being discovered, and can give rise to separated vertices in its decay, providing a spectacular signature.

Heavy photons have become a hot topic recently because they may explain high energy electrons and positrons in the cosmic rays, and be intimately linked to dark matter annihilation.

The first experiment is the APEX experiment, which has been conditionally approved at Jlab, and which is scheduled for a test run in June, 2010. The experiment makes use of two large spectrometers in Jlab's experimental Hall B to search for the heavy photon. If successful, several more data taking runs will be scheduled in 2010-2012. The experiment provides many opportunities for rotation students, and could provide data for a very topical particle physics thesis. SLAC has responsibilities for constructing the target for the experiment, and work on the target could commence immediately. Developing the physics analysis of the experimental data is another possibility.

The second experiment is the Heavy Photon Search Experiment (HPSE), which is in the design and proposal stage. Our SLAC group, in collaboration with other institutions, is currently designing the experiment, and will be submitting a proposal to Jlab by May, 2010. The experiment will use LHC style readout of silicon microstrip detectors and a PbWO4 crystal calorimeter to deal with the extremely high trigger rates expected. Rotation students could help with the design simulations, work on pattern recognition and vertexing, help develop the data acquisition system for the experiment, or work on the silicon tracking and vertexing hardware. This experiment is very small by modern standards, but exploits the latest high tech detection technologies to address a very fascinating piece of physics. It provides a perfect opportunity for a thesis student, offering all aspects of experimental work, from design to hardware implementation to data analysis.

Contact Person: John Jaros