Searching a dark photon with HADES

0428220 - ÚJF 2015 RIV NL eng J - Článek v odborném periodiku
Agakishiev, G. - Balanda, A. - Belver, D. - Belyaev, A. - Berger-Chen, J. C. - Blanco, A. - Böhmer, M. - Boyard, J. L. - Cabanelas, P. - Chernenko, S. - Dybczak, A. - Epple, E. - Fabbietti, L. - Fateev, O. - Krása, Antonín - Křížek, Filip - Kugler, Andrej - Sobolev, Yuri, G. - Tlustý, Pavel - Wagner, Vladimír … celkem 100 autorů
Searching a dark photon with HADES.
Physics Letters. B. Roč. 731, APR (2014), s. 265-271. ISSN 0370-2693. E-ISSN 1873-2445
Grant CEP: GA ČR GA13-06759S; GA MŠMT LG14004
Institucionální podpora: RVO:61389005
Klíčová slova: HADES * dark photon * hidden sector * dark matter * rare eta decays
Kód oboru RIV: BG - Jaderná, atomová a mol. fyzika, urychlovače
Impakt faktor: 6.131, rok: 2014

We present a search for the e(+)e(-) decay of a hypothetical dark photon, also named U vector boson, in inclusive dielectron spectra measured by HADES in the p(3.5 GeV) + p, Nb reactions, as well as the Ar (1.756 GeV/u) KCl reaction. An upper limit on the kinetic mixing parameter squared epsilon(2) at 90% CL has been obtained for the mass range M-U = 0.02-0.55 GeV/c(2) and is compared with the present world data set. For masses 0.03-0.1 GeV/c(2), the limit has been lowered with respect to previous results, allowing now to exclude a large part of the parameter region favored by the muon g - 2 anomaly. Furthermore, an improved upper limit on the branching ratio of 2.3 x 10(-6) has been set on the helicity-suppressed direct decay of the eta meson, eta --> e(+)e(-), at 90% CL.
Trvalý link: http://hdl.handle.net/11104/0233614