Observation of the rare Bs0 →µ+µ− decay from the combined analysis of CMS and LHCb data

and CMFV models, we demonstrate that these tensions can be removed in 331 models based on the gauge group SU(3) C × SU(3) L × U(1) X both for M Z in the LHC reach and well beyond it. But the implied new physics (NP) patterns in ∆F = 1 observables depend sensitively on the value of |V cb |. Concentrating the analysis on three 331 models that have been selected by us previously on the basis of their performance in electroweak precision tests and ε /ε we illustrate this for |V cb | = 0.042 and |V cb | = 0.040. We find that these new lattice data still allow for positive shifts in ε /ε up to 6 × 10 −4 for M Z = 3 TeV and |V ub | = 0.0036 for both values of |V cb | but for M Z = 10 TeV only for |V cb | = 0.040 such shifts can be obtained. For |V ub | = 0.0042 maximal shifts in ε /ε increase to 7×10 −4 . NP effects in B s → µ + µ − and in the Wilson coefficient C 9 are significantly larger in all three models for the case of |V cb | = 0.040. In particular in two models the rate for B s → µ + µ − can be reduced by NP by 20% for M Z = 3 TeV resulting in values in the ballpark of central values from CMS and LHCb. In the third model a shift in C 9 up to C NP 9 = −0.5 is possible. For |V cb | = 0.042, NP effects in B s → µ + µ − and in C 9 are by at least a factor of two smaller. For M Z = 10 TeV NP effects in B s → µ + µ − and C 9 , independently of |V cb |, are at most at the level of a few percent. We also consider the simplest 331 model, analyzed recently in the literature, in which X = Y , the usual hypercharge. We find that JHEP08 (2016)115 in this model NP effects in flavour observables are much smaller than in the three models with X = Y , in particular NP contributions to the ratio ε /ε are very strongly suppressed. Our analysis exhibits the important role of lattice QCD and of precise values of CKM parameters, in particular |V cb |, for quark flavour phenomenology beyond the SM. It also demonstrates exceptional role of ∆F = 2 observables and of ε /ε in testing high energy scales beyond the LHC.

Section: Jhep08(2016)115supporting

confidence: 55%

331 Models Facing the Tensions in ΔF = 2 Processes with the Impact on ε ′ /ε, B s → μ + μ − and B →K ∗ μ + μ −

Buras

Fazio

2016

“…[58]. Since then the ATLAS Collaboration also measured this same decay mode and reported B(Bs → µ + µ − ) exp = (0.9 [59].…”

Section: Which Leptoquark Model?mentioning

confidence: 99%

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

Bečirević

Košnik

Sumensari

et al. 2016

175

121

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 ).

“…The rare flavor-changing neutral current decay B s → µ + µ − has been recently observed by the LHCb collaboration with a branching fraction [64] …”

Section: Jhep07(2017)102mentioning

confidence: 99%

Lepton-flavor universality violation in R K and R D ∗ $$ {R}_{D^{{}_{\left(\ast \right)}}} $$ from warped space

Megías

Quirós

Salas

2017

Some anomalies in the processes b → s ( = µ, e) and b → c ν ( = τ, µ, e), in particular in the observables R K and R D ( * ) , have been found by the BaBar, LHCb and Belle collaborations, leading to a possible lepton flavor universality violation. If these anomalies were confirmed they would inevitably lead to physics beyond the Standard Model. In this paper we try to accommodate the present anomalies in an extra dimensional theory, solving the naturalness problem of the Standard Model by means of a warped metric with a strong conformality violation near the infra-red brane. The R K anomaly can be accommodated provided that the left-handed bottom quark and muon lepton have some degree of compositeness in the dual theory. The theory is consistent with all electroweak and flavor observables, and with all direct searches of Kaluza-Klein electroweak gauge bosons and gluons. The fermion spectrum, and fermion mixing angles, can be reproduced by mostly elementary right-handed bottom quarks, and tau and muon leptons. Moreover the R D ( * ) anomaly requires a strong degree of compositeness for the left-handed tau leptons, which turns out to be in tension with experimental data on the g Z τ L coupling, possibly unless some degree of fine-tuning is introduced in the fixing of the CKM matrix.