Minimal Unified Resolution to RK(*) and R(D(<

Abstract

It is a challenging task to explain, in terms of a simple and compelling new physics scenario, the intriguing discrepancies between the standard model expectations and the data for the neutralcurrent observables RK and RK * , as well as the charged-current observables R(D) and R(D * ). We show that this can be achieved in an effective theory with only two unknown parameters. In addition, this class of models predicts some interesting signatures in the context of both B decays as well as high-energy collisions.Introduction and the data -Several recent hints of discrepancies in a few charged-as well as neutral-current semileptonic decays of B-mesons have intrigued the community. Unlike the case for fully hadronic decay modes that suffer from large (and, in some cases, not-so-well understood) strong interaction corrections, the theoretical uncertainties in semileptonic decays are much better controlled. Even these uncertainties are removed to a great extent in ratios of similar observables. While, individually, none of the observables, militate against the standard model (SM), viewed together, they strongly suggest that some new physics (NP) is lurking around the corner [1,2]. The pattern also argues convincingly for the violation of lepton-flavor universality.With the ratios of partial widths being particularly clean probes of physics beyond the SM, on account of the cancellation of the leading uncertainties, let us focus on R(D) and R(D * ) defined as

Optimal observable analysis for the decay $$b \rightarrow s$$ b → s plus missing energy

“…A typical case of how crucial the invisible channel can be for the explanation of the apparent anoma-lies in the semileptonic decays of the B meson has been exemplified in Ref. [3] As an example of what we have just said, let us note that apart from neutrinos coming from non-SM operators, the FCNC transition b → s can involve light invisible scalars in the final state. If they are singlet under all the SM gauge groups, they can very well be a candidate for cold dark matter (DM).…”

A nonunitary interpretation for a single vector leptoquark combined explanation to the B-decay anomalies

“…It is thus desirable to consider which BSM constructions could be at the origin of these effective operators. Among the most minimal scenarios studied, one has flavour-sensitive Z exchanges [37][38][39][40][41][42][43][44][45][46][47][48][49][50], leptoquark exchanges , R−parity violating supersymmetric models [76][77][78][79][80][81], and various other constructions [82][83][84][85][86][87][88][89][90][91].…”

Search for an opposite sign muon-tau pair and a b -jet at the LHC in the context of flavor anomalies

“…In the present case, instead of attempting a generic study, we consider a particular signature, at the LHC, prompted by the scenarios discussed in Refs. [1,2]. Some such studies have been attempted in the past, but in entirely different contexts, both at the simulation level [53][54][55][56][57][58][59][60], as well as by the ATLAS and CMS collaborations who have searched for flavor violating signatures with dilepton final states [61][62][63][64][65][66].…”

“…Recent studies (Refs. [1,2]) have shown that a class of effective field theory (EFT) models may explain such anomalies in terms of only a few parameters which can be determined phenomenologically. In this literature, we examine such resolutions in the context of the requisite (s b)(τ τ ) operator, and look for its signals at the 13 TeV LHC, with a final state of one b-jet, and an oppositely charged µ-τ pair, with the muon coming from the decay of one of the τ leptons.…”