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 theory of Higgs flavor violation and 
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Altmannshofer, Wolfgang; Carena, Marcela; Crivellin, Andreas

doi:10.1103/physrevd.94.095026

Cited by 97 publications

(64 citation statements)

References 102 publications

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“…An explanation of the anomalies via loop effects, on the other hand, typically leads to correlated imprints on other observables like the anomalous magnetic moment of the muon (a µ ). It is thus appealing to investigate the possibility of a simultaneous solution of the flavor anomalies and the long-standing tension in (g − 2) µ at the loop level, for example by light Z bosons [39][40][41][42][43][44][45][46][47][48], leptoquarks [38,49,50] or new fermions and scalars [51][52][53][54][55][56][57][58][59][60][61] (see ref. [62] for a review on the situation in SUSY).…”

Section: Jhep04(2017)043mentioning

confidence: 99%

Loop effects of heavy new scalars and fermions in b → sμ + μ −

Arnan

Crivellin

Hofer

et al. 2017

J. High Energ. Phys.

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127

190

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Recent measurements of b → sµ + µ − processes at LHCb and BELLE have revealed tensions at the 2 − 3 σ level between the Standard Model (SM) prediction and the experimental results in the channels B → K * µ + µ − and B s → φµ + µ − , as well as in the lepton-flavor universality violating observable R K = Br(B → Kµ + µ − )/Br(B → Ke + e − ). Combined global fits to the available b → sµ + µ − data suggest that these tensions might have their common origin in New Physics (NP) beyond the SM because some NP scenarios turn out to be preferred over the SM by 4 − 5 σ. The fact that all these anomalies are related to muons further suggests a connection (and a common NP explanation) with the long-standing anomaly in the anomalous magnetic moment of the muon, a µ . In this article, we study the impact of a generic class of NP models featuring new heavy scalars and fermions that couple to the SM fermions via Yukawa-like interactions. We consider two different scenarios, introducing either one additional fermion and two scalars or two additional fermions and one scalar, and examine all possible representations of the new particles under the SM gauge group with dimension up to the adjoint one. The models induce one-loop contributions to b → sµ + µ − and a µ which are capable of solving the respective anomalies at the 2σ level, albeit a relatively large coupling of the new particles to muons is required. In the case of b → sµ + µ − , stringent constraints from B s − B s mixing arise which can be relaxed if the new fermion is a Majorana particle.

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Section: Jhep04(2017)043mentioning

confidence: 99%

Loop effects of heavy new scalars and fermions in b → sμ + μ −

Arnan

Crivellin

Hofer

et al. 2017

J. High Energ. Phys.

Self Cite

127

190

View full text Add to dashboard Cite

show abstract

“…Therefore, it is well motivated to search for a simultaneous explanation of these two anomalies [8][9][10][11][12][13][14][15][16][17][18][19][20]. Furthermore, since a e agrees with the SM prediction, also a µ can be considered as a LFUV quantity and one can address it together with R(D ( * ) ) and/or b → sµ + µ − [13,[21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Simultaneous explanation of R(D (∗)) and b→sμ + μ −: the last scalar leptoquarks standing

Crivellin

Müller

Ota

2017

J. High Energ. Phys.

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324

254

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Over the past years, experiments accumulated intriguing hints for new physics (NP) in flavor observables, namely in the anomalous magnetic moment of the muon (a µ ), in R(D ( * ) ) = Br(B → D ( * ) τ ν)/Br(B → D ( * ) ν) and in b → sµ + µ − transitions, which are all at the 3 − 4 σ level. In this article we point out that one can explain the R(D ( * ) ) anomaly using two scalar leptoquarks (LQs) with the same mass and coupling to fermions related via a discrete symmetry: an SU(2) L singlet and an SU(2) L triplet, both with hypercharge Y = −2/3. In this way, potentially dangerous contributions to b → sνν are avoided and non-CKM suppressed effects in R(D ( * ) ) can be generated. This allows for smaller overall couplings to fermions weakening the direct LHC bounds. In our model, R(D ( * ) ) is directly correlated to b → sτ + τ − transitions where an enhancement by orders of magnitude compared to the standard model (SM) is predicted, such that these decay modes are in the reach of LHCb and BELLE II. Furthermore, one can also naturally explain the b → sµ + µ − anomalies (including R(K)) by a C 9 = −C 10 like contribution without spoiling µ − e universality in charged current decays. In this case sizable effects in b → sτ µ transitions are predicted which are again well within the experimental reach. One can even address the longstanding anomaly in a µ , generating a sizable decay rate for τ → µγ. However, we find that out of the three anomalies R(D ( * ) ), b → sµ + µ − and a µ only two (but any two) can be explained simultaneously. We point out that a very similar phenomenology can be achieved using a vector leptoquark SU(2) L singlet with hypercharge 2/3. In this case, no tuning between couplings is necessary, but the model is non-renormalizable.

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“…For other recent studies on gauged U(1) L μ −L τ models, see Refs. [23][24][25][26][27][28][29][30][31][32][33][34][35].…”

Section: Introductionmentioning

confidence: 99%

Predictions for the neutrino parameters in the minimal gauged $$\hbox {U}(1)_{L_\mu -L_\tau }$$ U ( 1 ) L μ - L τ model

2017

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We study the structure of the neutrino-mass matrix in the minimal gauged U(1) L μ −L τ model, where three right-handed neutrinos are added to the Standard Model in order to obtain non-zero masses for the active neutrinos. Because of the U(1) L μ −L τ gauge symmetry, the structure of both Dirac and Majorana mass terms of neutrinos is tightly restricted. In particular, the inverse of the neutrinomass matrix has zeros in the (μ, μ) and (τ, τ ) components, namely, this model offers a symmetric realization of the socalled two-zero-minor structure in the neutrino-mass matrix. Due to these constraints, all the CP phases -the Dirac CP phase δ and the Majorana CP phases α 2 and α 3 -as well as the mass eigenvalues of the light neutrinos m i are uniquely determined as functions of the neutrino mixing angles θ 12 , θ 23 , and θ 13 , and the squared mass differences m 2 21 and m 2 31 . We find that this model predicts the Dirac CP phase δ to be δ 1.59π -1.70π (1.54π -1.78π ), the sum of the neutrino masses to be i m i 0.14-0.22 eV (0.12-0.40 eV), and the effective mass for the neutrinoless double-beta decay to be m ββ 0.024-0.055 eV (0.017-0.12 eV) at 1σ (2σ ) level, which are totally consistent with the current experimental limits. These predictions can soon be tested in future neutrino experiments. Implications for leptogenesis are also discussed.

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Lμ−Lτ theory of Higgs flavor violation and (g−2)μ

Cited by 97 publications

References 102 publications

Loop effects of heavy new scalars and fermions in b → sμ + μ −

Loop effects of heavy new scalars and fermions in b → sμ + μ −

Simultaneous explanation of R(D (∗)) and b→sμ + μ −: the last scalar leptoquarks standing

Predictions for the neutrino parameters in the minimal gauged $$\hbox {U}(1)_{L_\mu -L_\tau }$$ U ( 1 ) L μ - L τ model

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