Palatable leptoquark scenarios for lepton flavor violation in exclusive b → sℓ 1 ℓ 2 modes

Abstract

We examine various scenarios that involve a light O(1 TeV) leptoquark state and select those which are compatible with the current experimental values for B(B s → µµ), B(B → Kµµ) large−q 2 , R K = B (B → Kµµ)/B (B → Kee), and which lead to predictions consistent with other experimental data. We show that two such scenarios are phenomenologically plausible, namely the one with a doublet of scalar leptoquarks of hypercharge 1/6, and the one with a triplet of vector leptoquarks of hypercharge 2/3. We also argue that a model with a singlet scalar leptoquark of hypercharge 1/3 is not viable. Using the present experimental data as constraints, it is shown that the exclusive lepton flavor violating decays, B(B s → µτ ), B(B → Kµτ ) and B(B → K * µτ ), can be as large as O(10 −5 ).

A leptoquark model to accommodate R K exp < R K SM and R K ∗ exp < R K ∗

“…That induced problems elsewhere in phenomenology, ultimately making that particular model phenomenologically unviable, see discussion in ref. [30]. In our model, the dominant top quark contribution provides C µµ 9 < 0, as needed, without inducing phenomenological problems elsewhere.…”

“…[30,33], and for three separate intervals in q 2 . To make the comparison with experiment easier we consider three intervals:…”

LHCb anomalies from a natural perspective

“…Alternative explanations of these b → s anomalies already present in the literature include the presence of new spin-1 resonances (Z ) [30][31][32][33][34][35][36][37][38][39][40][41][42][43][44], or models including leptoquarks [45][46][47][48][49][50][51]. Most of these scenarios need to assume the presence of extra states with the only purpose of accommodating anomalous b → s measurements.…”

Direct determination of Wilson coefficients using B0 → K∗0μ+μ− decays

“…Nuisance parameters that can impact the significance of the deviation are the hadronic form factor parameters and uncertainties on subleading Λ QCD /m b suppressed corrections of QCD factorisation. The deviations in the angular observables can be interpreted as signs of NP, most notably new heavy Z gauge bosons [32][33][34][35][36][37][38][39][40][41][42][43][44][45][46] or leptoquarks [47][48][49][50][51][52][53][54][55][56][57][58][59][60][61]. However, the B 0 → K * 0 µ + µ − angular observables can also be affected by contributions from SM cc-loop processes [62][63][64][65], which are part of the Λ QCD /m b corrections.…”