Search for a new gauge boson in electron-nucleus fixed-target scattering by the APEX experiment

S. Abrahamyan*, Z. Ahmed, K. Allada, D. Anez, T. Averett, A. Barbieri, K. Bartlett, J. Beacham, J. Bono, J. R. Boyce, P. Brindza, A. Camsonne, K. Cranmer, M. M. Dalton, C. W. De Jager, J. Donaghy, R. Essig, C. Field, E. Folts, A. GasparianN. Goeckner-Wald, J. Gomez, M. Graham, J. O. Hansen, D. W. Higinbotham, T. Holmstrom, J. Huang, S. Iqbal, J. Jaros, E. Jensen, A. Kelleher, M. Khandaker, J. J. Lerose, R. Lindgren, N. Liyanage, E. Long, J. Mammei, P. Markowitz, T. Maruyama, V. Maxwell, S. Mayilyan, J. McDonald, R. Michaels, K. Moffeit, V. Nelyubin, A. Odian, M. Oriunno, R. Partridge, M. Paolone, E. Piasetzky, I. Pomerantz, Y. Qiang, S. Riordan, Y. Roblin, B. Sawatzky, P. Schuster, J. Segal, L. Selvy, A. Shahinyan, R. Subedi, V. Sulkosky, S. Stepanyan, N. Toro, D. Walz, B. Wojtsekhowski, J. Zhang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


We present a search at the Jefferson Laboratory for new forces mediated by sub-GeV vector bosons with weak coupling α to electrons. Such a particle A can be produced in electron-nucleus fixed-target scattering and then decay to an e+e- pair, producing a narrow resonance in the QED trident spectrum. Using APEX test run data, we searched in the mass range 175-250 MeV, found no evidence for an A →e+e- reaction, and set an upper limit of α/αA10-6. Our findings demonstrate that fixed-target searches can explore a new, wide, and important range of masses and couplings for sub-GeV forces.

Original languageEnglish
Article number191804
JournalPhysical Review Letters
Issue number19
StatePublished - 4 Nov 2011


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