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

/ Authors

S. Abrahamyan, Z. Ahmed, K. Allada, D. Anez, T. Averett, A. Barbieri, K. Bartlett, J. Beacham, J. Bono, J. Boyce

and 60 more authors

P. Brindza, A. Camsonne, K. Cranmer, M. Dalton, C. Jager, C. Jager, J. Donaghy, R. Essig, C. Field, E. Folts, A. Gasparian, N. Goeckner-wald, J. Gomez, M. Graham, J. Hansen, D. Higinbotham, T. Holmstrom, J. Huang, S. Iqbal, J. Jaros, E. Jensen, A. Kelleher, M. Khandaker, M. Khandaker, 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, P. Schuster, J. Segal, L. Selvy, A. Shahinyan, R. Subedi, V. Sulkosky, S. Stepanyan, Natalia Toro, Natalia Toro, D. Walz, B. Wojtsekhowski, J. Zhang

/ Abstract

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'/α ~/= 10(-6). Our findings demonstrate that fixed-target searches can explore a new, wide, and important range of masses and couplings for sub-GeV forces.

Journal: Physical review letters

DOI: 10.1103/PhysRevLett.107.191804