2021/08/12 by Alok, Ashutosh Kumar, Dighe, Amol, Gangal, Shireen +1
#FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High Energy Physics - Phenomenology (hep-ph)
paper · doi:10.48550/arxiv.2108.05614
The measurements of the Cabibbo--Kobayashi--Maskawa (CKM) elements can be contaminated by new-physics effects. We point out that purely leptonic operators at the high scale can influence semileptonic K decays and nuclear beta decay through renormalization group (RG) running, and hence can influence the measurements of Vus. Interestingly, through this mechanism, a single six-dimensional effective operator Oℓℓ at the high scale can alleviate the tension due to the Cabibbo angle anomaly, by generating the desired operators at the low scale through RG running. When generated as a result of a Z' model, the non-universal leptonic couplings of this operator can also contribute to the lepton flavor universality violating ratios such as RK(*), which would act as stringent constraints on such scenarios. By performing a global fit of the Z' model, we find that it is essential to have non-universal couplings of such a Z' boson to all three generations of leptons.