TY - JOUR
T1 - The 17 MeV anomaly in beryllium decays and U (1) portal to dark matter
AU - Chen, Chian Shu
AU - Lin, Guey Lin
AU - Lin, Yen Hsun
AU - Xu, Fanrong
N1 - Funding Information:
C.-S Chen is supported by the Ministry of Science and Technology (MOST), Taiwan, R.O.C. under Grant No. 104-2112-M-001-042-MY3; G.-L. Lin and Y.-H. Lin are supported by the Ministry of Science and Technology, Taiwan under Grant No. 104-2112-M-009-021. F. Xu is supported by NSFC under Grant No. 11605076 as well as the Fundamental Research Funds for the Central Universities in China under the Grant No. 21616309. Especially, F. Xu would like to acknowledge the hospitality of the Institute of Physics, Academia Sinica, at which part of the work was done.
Publisher Copyright:
© 2017 World Scientific Publishing Company.
PY - 2017/11/10
Y1 - 2017/11/10
N2 - The experiment of Krasznahorkay et al. observed the transition of a 8Be excited state to its ground state and accompanied by an emission of an e+e- pair with 17 MeV invariant mass. This 6.8σ anomaly can be fitted by a new light gauge boson. We consider the new particle as a U(1) gauge boson, Z′, which plays as a portal linking dark sector and visible sector. In particular, we study the new U(1) gauge symmetry as a hidden or nonhidden group separately. The generic hidden U(1) model, referred to as dark Z model, is excluded by imposing various experimental constraints. On the other hand, a nonhidden Z′ is allowed due to the additional interactions between Z′ and Standard Model fermions. We also study the implication of the dark matter direct search on such a scenario. We found that the search for the DM-nucleon scattering cannot probe the parameter space that is allowed by 8Be-anomaly for the range of DM mass above 500 MeV. However, the DM-electron scattering for DM between 20 MeV and 50 MeV can test the underlying U(1) portal model using the future Si and Ge detectors with the 5e- threshold charges.
AB - The experiment of Krasznahorkay et al. observed the transition of a 8Be excited state to its ground state and accompanied by an emission of an e+e- pair with 17 MeV invariant mass. This 6.8σ anomaly can be fitted by a new light gauge boson. We consider the new particle as a U(1) gauge boson, Z′, which plays as a portal linking dark sector and visible sector. In particular, we study the new U(1) gauge symmetry as a hidden or nonhidden group separately. The generic hidden U(1) model, referred to as dark Z model, is excluded by imposing various experimental constraints. On the other hand, a nonhidden Z′ is allowed due to the additional interactions between Z′ and Standard Model fermions. We also study the implication of the dark matter direct search on such a scenario. We found that the search for the DM-nucleon scattering cannot probe the parameter space that is allowed by 8Be-anomaly for the range of DM mass above 500 MeV. However, the DM-electron scattering for DM between 20 MeV and 50 MeV can test the underlying U(1) portal model using the future Si and Ge detectors with the 5e- threshold charges.
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U2 - 10.1142/S0217751X17501780
DO - 10.1142/S0217751X17501780
M3 - Article
AN - SCOPUS:85033551190
SN - 0217-751X
VL - 32
JO - International Journal of Modern Physics A
JF - International Journal of Modern Physics A
IS - 31
M1 - 1750178
ER -