On Branching Ratios of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"><mml:msub><mml:mrow><mml:mi>B</mml:mi></mml:mrow><mml:mrow><mml:mi>s</mml:mi></mml:mrow></mml:msub></mml:math> Decays and the Search for New Physics in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.gif" overflow="scroll"><mml:msubsup><mml:mrow><mml:mi>B</mml:mi></mml:mrow><mml:mrow><mml:mi>s</mml:mi></mml:mrow><mml:mrow><mml:mn>0</mml:mn></mml:mrow></mml:msubsup><mml:mo>

Abstract:We investigate how the 331 models, based on the gauge group SU(3) C × SU(3) L ×U(1) X face new data on B s,d → µ + µ − and B d → K * (K)µ + µ − taking into account present constraints from ∆F = 2 observables, low energy precision measurements, LEP-II and the LHC data. In these models new sources of flavour and CP violation originate dominantly through flavour violating interactions of ordinary quarks and leptons with a new heavy Z gauge boson. The strength of the relevant couplings is governed by four new parameters in the quark sector and the parameter β which in these models determines the charges of new heavy fermions and gauge bosons. We study the implications of these models for β = ±n/ √ 3 with n = 1, 2, 3. The case β = − √ 3 leading to Landau singularities for M Z ≈ 4 T eV can be ruled out when the present constraints on Z couplings, in particular from LEP-II, are taken into account. For n = 1, 2 interesting results are found for M Z < 4 T eV with largest NP effects for β < 0 in B d → K * µ + µ − and the ones in B s,d → µ + µ − for β > 0. As Re(C NP 9 ) can reach the values −0.8 and −0.4 for n = 2 and n = 1, respectively the B d → K * µ + µ − anomalies can be softened with the size depending on ∆M s /(∆M s ) SM and the CP-asymmetry S ψφ . A correlation between Re(C NP 9 ) and B(B s → µ + µ − ), identified for β < 0, implies for negative Re(C NP 9 ) uniquely suppression of B(B s → µ + µ − ) relative to its SM value which is favoured by the data. In turn also S ψφ < S SM ψφ is favoured with S ψφ having dominantly opposite sign to S SM ψφ and closer to its central experimental value. Another triple correlation is the one between Re(C NP 9 ), B(B s → µ + µ − ) and B(B d → Kµ + µ − ). NP effects in b → sνν transitions, K + → π + νν and K L → π 0 νν turn out to be small. We find that the absence of B d → K * µ + µ − anomalies in the future data and confirmation of the suppression of B(B s → µ + µ − ) relative to its SM value would favour β = 1/ √ 3 and M Z ≈ 3 T eV . Assuming lepton universality, we find an upper bound |C NP 9 | ≤ 1.1(1.4) from LEP-II data for all Z models with only left-handed flavour violating couplings to quarks when NP contributions to ∆M s at the level of 10%(15%) are allowed.

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331 models facing new b → sμ + μ − data

Buras

Fazio

Girrbach

2014

J. High Energ. Phys.

224

243

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$ B_{s,d}^0 $ → ℓ + ℓ − decays in the aligned two-Higgs-doublet model

Pich

2014

J. High Energ. Phys.

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Abstract:The rare decays B 0 s,d → + − are analyzed within the general framework of the aligned two-Higgs doublet model. We present a complete one-loop calculation of the relevant short-distance Wilson coefficients, giving a detailed technical summary of our results and comparing them with previous calculations performed in particular limits or approximations. We investigate the impact of various model parameters on the branching ratios and study the phenomenological constraints imposed by present data.

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Left-handed Z′ and Z FCNC quark couplings facing new b → sμ + μ − data

Buras

Girrbach

2013

J. High Energ. Phys.

170

122

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In view of the recent improved data on B s,d → µ + µ − and B d → K * µ + µ − we revisit two simple New Physics (NP) scenarios analyzed by us last year in which new FCNC currents in b → sµ + µ − transitions are mediated either entirely by a neutral heavy gauge boson Z with purely left-handed complex couplings ∆ qb L (Z ) (q = d, s) and real couplings to muons ∆ µμ A (Z ) and ∆ µμ V (Z ) or the SM Z boson with left-handed complex couplings ∆ qb L (Z). We demonstrate how the reduced couplings, the couplings in question divided by M Z or M Z , can be determined by future ∆F = 2 and b → sµ + µ − observables up to sign ambiguities. The latter do not affect the correlations between various observables that can test these NP scenarios. We present the results as functions of C Bq = ∆M q /(∆M q ) SM , S ψφ and S ψK S which should be precisely determined in this decade. We calculate the violation of the CMFV relation between B(B s,d → µ + µ − ) and ∆M s,d in these scenarios. We find that the data on B s,d → µ + µ − from CMS and LHCb can be reproduced in both scenarios but in the case of Z, ∆M s and S ψφ have to be very close to their SM values. As far as B d → K * µ + µ − anomalies are concerned the Z scenario can significantly soften these anomalies while the Z boson fails badly because of the small vector coupling to muons. We also point out that recent proposals of explaining these anomalies with the help of a real Wilson coefficient C NP 9 implies uniquely an enhancement of ∆M s with respect to its SM value, while a complex C NP 9 allows for both enhancement and suppression of ∆M s and simultaneously novel CPviolating effects. Correlations between b → sµ + µ − and b → sνν observables in these scenarios are emphasized. We also discuss briefly scenarios in which the Z boson has right-handed FCNC couplings. In this context we point out a number of correlations between angular observables measured in B d → K * µ + µ − that arise in the absence of new CP-violating phases in scenarios with only left-handed or right-handed couplings or scenarios in which left-handed and right-handed couplings are equal to each other or differ by sign.

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On Branching Ratios of Bs Decays and the Search for New Physics in Bs0

Cited by 38 publications

References 36 publications

331 models facing new b → sμ + μ − data

331 models facing new b → sμ + μ − data

$ B_{s,d}^0 $ → ℓ + ℓ − decays in the aligned two-Higgs-doublet model

Left-handed Z′ and Z FCNC quark couplings facing new b → sμ + μ − data

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