Linking RK(.) anomalies to Hubble tension via a single right-handed neutrino

作者：Duan, Wen-Feng; Li, Shao-Ping; Li, Xin-Qiang^*; Yang, Ya-Dong

来源：Chinese Physics C, 2023, 47(3).

DOI：10.1088/1674-1137/aca888

• rare B-meson decays
• new physics beyond the SM
• Hubble tension
• right-handed neutrino

Updated measurements from the LHCb and SH0ES collaborations have respectively strengthened the de-viations of the ratio in rare semi-leptonic-meson decays and the present-day Hubble parameter in the Uni-RK B H-0 verse, implying tantalizing hints of new physics beyond the standard model. In this paper, we consider a simple flavor-specific two-Higgs-doublet model, where long-standing anomalies can be addressed by a one-flavor right-R-K(*) handed neutrino. An intriguing prediction resulting from the parameter space for the R(K(*) )resolution under flavor-and collider-physics constraints points toward a shift in the effective neutrino ?N(eff )number, =N-eff - N-SM (eff) ,as afavored way to ease the tension. Depending on whether the neutrino is of the Dirac or Majorana type, we show H0 that the resulting shift?N-eff is ?1.0 for the former case?and N-eff? 0.5 for the latter case. While the Dirac case is disfavored by the CMB polarization measurements, the Majorana solution is consistent with recent studies using a combined dataset from various sources. Consequently, such a simple flavor-specific two-Higgs-doublet model provides a link between anomalies and tension, which in turn can be readily verified or disproved by up-R-K(*) H-0 coming measurements.

• 单位
  北京大学