New light mediators for the R-K and R-K(*) puzzles

作者：Datta Alakabha^*; Kumar Jacky; Liao Jiajun; Marfatia Danny

来源：PHYSICAL REVIEW D, 2018, 97(11): 115038.

DOI：10.1103/PhysRevD.97.115038

The measurements of R-K and R-K* provide hints for the violation of lepton universality. However, it is generally difficult to explain the R-K* measurement in the low q(2) range, 0.045 <= q(2) <= 1.1 GeV2 . Light mediators offer a solution by making the Wilson coefficients q(2) dependent. We check if new lepton nonuniversal interactions mediated by a scalar (S) or vector particle (Z') of mass between 10-200 MeV can reproduce the data. We find that a 25 MeV Z' with a q(2)-dependent b - s coupling and that couples to the electron but not the muon can explain all three anomalies in conjunction with other measurements. A similar 25 MeV S provides a good fit to all relevant data except R-K* in the low q(2) bin. A 25 MeV Z' with a q(2)-dependent b - s coupling and that couples to the muon but not the electron provides a good fit to the combination of the R-K and R-K* data, but does not fit R-K* in the low q(2) bin well.

• 出版日期2018-6-21