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The Heavy Photon Search Group at SLAC is collaborating with physicists at Jefferson Lab, Fermilab, UCSC, Italy, and UCSC France&nbsp;in twoan experimentsexperiment aimed at discovering a hidden-sector, heavy photon. Such a particle would have mass in the range 0.02 to 1.0 GeV, couple weakly to electrons, and decay to {html}e<sup>e<SUP>+</sup>e<sup>&ndash;</sup>SUP>e<SUP>–</SUP>{html}. It would be produced by electron bremstrahlung on a heavy target, and be identified as a narrow {html}e<sup>e<SUP>+</sup>e<sup>&ndash;</sup>SUP>e<SUP>–</SUP>{html} resonance. The very Weakweak couplings of thisthe heavy photon to electrons account for its having not yet been discovered and can give rise to separated vertices in its decay, providing a spectacular signature. Heavy photons have become a hot topic recently&nbsp; because they may explain high energy electrons and positrons in cosmic rays and be intimately linked to dark matter annihilation.

 and the existence of hidden sectors.&nbsp;Our primary effort at SLAC is the Heavy Photon Search experiment (HPS). During the2011 pastand year2012, we built, installed, commissioned, and ran the HPS Test Run Experiment at JLab during Spring 2012. The experiment used LHC style readout of silicon microstrip detectors for tracking and vertex reconstruction of {html}e<sup>e<SUP>+</sup>e<sup>&ndash;</sup>SUP>e<SUP>–</SUP>{html} pairs and a PbWO{~}4~ crystal calorimeter to deal with the extremely high trigger rates expected. The run successfully demonstrated thethat technicalbackgrounds feasibilityare ofmanageable the experiment, soand that the JLABapparatus programworked committeeas rewardeddesigned. us with a 6 week data takingFollowing the run atand the endsubmission of 2014. An extended run in 2015 is likely as well. Both these runs will use a new apparatusproposal, DOE has justapproved nowand infunded the designexperiment phase,and butJLAB basedhas onfully theapproved technologiesHPS and techniquesscheduled wetimrunning demonstratedtime in the2014 Test Run. and 2015&nbsp;

HPS offers many opportunities for rotation students. Experimental design and simulationSimulation studies are needed, tracking pattern recognition and vertexing code is being improved, the data acquisition system for the experiment is being refined and upgraded, a new silicon tracker/vertexer mustis bebeing designed and built, detector monitoring software is being coded,&nbsp;and the physics analysis is being developed. This experiment is very small by modern standards, but exploits cutting edge detection and readout 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. Rotation SomeProjects ofare theavailable previousfor HPSthe rotation2013-2014 projectsacademic areyear, listedoutlined below. New projects will be added.&nbsp;

Our SLAC group is also involved in the APEX experiment, which has already completed a test run in 2010 and published results of its initial search, excluding a new region of heavy photon parameter space. The experiment makes use of two existing spectrometers in Jlab's experimental Hall A. The experiment hopes to take more data during the 2013-2014 JLab cycle and we hope to contribute. [John Jaros|mailto:john@slac.stanford.edu].

h2.


h2. Fall/WinterPossible 2011 ProjectsProjects for&nbsp;2013-2014

|| *Project Title* || *Contact Person* || Student ||
| [Silicon Tracker Module and DAQ Development|Project Description - Silicon Tracker Module and DAQ Development] Tracker Module Construction and Test | [Tim Nelson|mailto:tkelson@slac.stanford.edu] | |
| [HPS Trigger Simulation Beamline|hpsg:HPS trigger simulation] Protection Studies | [Takashi Maruyama|mailto:tvm@slac.stanford.edu] | |
| [Optimizing|hpsg:Simulating HPS performance in a photon beam] |hpsg:Simulatingthe HPS performance in a photon beam]Design | [Takashi MaruyamaMatt|mailto:tvm@slac.stanford.edu] Graham | |
| [Hybrid|hpsg:Magnetic Field Map for Track Reconstruction] and Readout Construction and Test | [Matt GrahamPer|mailto:mgraham@slac.stanford.edu] Hansson | |
| [HPS|hpsg:Tracker Alignment Procedures] Trigger Studies | [Matt GrahamSho|mailto:mgraham@slac.stanford.edu] Uemura | |
| [New|hpsg:Optimizing HPS Design] |Beam [Matt Graham|mailto:mgraham@slac.stanford.edu] | |


h2. Spring/Summer 2012 Projects

|| *Project Title* || *Contact Person* || Student ||
| Test Run Occupancy Studies | [Tim Nelson|mailto:tknelson@slac.stanford.edu] | |
| Determine Test Run Tracker Alignment | [Matt Graham|mailto:Dump Experiment | T[akashi|mailto:mgraham@slac.stanford.edu] | |
| Test Run Trigger Studies | [Takashi Maruyama|mailto:tvm@slac.stanford.edu] | |