B-decay discrepancies after Moriond 2019

Aebischer, Jason; Altmannshofer, Wolfgang; Guadagnoli, Diego; Reboud, M.; Stangl, Peter; Straub, David M.

doi:10.1140/epjc/s10052-020-7817-x

Cited by 287 publications

(416 citation statements)

References 133 publications

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“…With regards to b → s + − decay processes, we fit the Wilson coefficients for new physics contributions as discussed in Ref. [52]. Only two of the five possible good fit points of this analysis can be fit in our model.…”

Section: Discussionmentioning

confidence: 99%

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Complete vectorlike fourth family with U(1)′ : A global analysis

2020

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In this paper we present an in-depth analysis of a recently proposed Standard Model extension with a complete fourth generation of quarks and leptons, which are vector-like with respect to the Standard Model gauge group and charged under a new spontaneously broken vector-like U(1) gauge symmetry. The model is designed to explain the known muon anomalies, i.e. the observed deviations from Standard Model predictions in the anomalous magnetic moment of the muon, ∆a µ , and in b → s + − processes. We perform a global χ 2 analysis of the data with 65 model parameters and including 98 observables. We find many points with χ 2 per degree of freedom ≤ 1. The vector-like leptons and the new heavy Z are typically much lighter than a TeV and would, thus, be eminently visible at the HL-LHC.

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Section: Discussionmentioning

confidence: 99%

“…We note that BR(B s → µ + µ − ) is included in the analysis of Ref. [52], where due to the tension a larger C µ 10 is favored. Nonetheless, we additionally include BR(B s → µ + µ − ) individually in our χ 2 analysis in order to take into account scalar contributions which were not included in [52].…”

Section: Neutral Meson Mixingmentioning

confidence: 99%

Complete vectorlike fourth family with U(1)′ : A global analysis

2020

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“…The most recent averages from the data of CMS, LHCb and ATLAS [53][54][55][56] have been presented in [23] by about 2σ. This favoures NP scenarios in which the branching ratio for this decay is suppressed relatively to its SM value [23]…”

Section: Results In Scenario B1mentioning

confidence: 99%

“…Recently, some correlations between B-physics anomalies and in particular τ decays through renormalization group effects have been pointed out in various papers but mostly in the context of leptoquark models or in the context of SMEFT analyses of these anomalies. Selected papers can be found in [20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Quark-lepton connections in Z′ mediated FCNC processes: gauge anomaly cancellations at work

Aebischer

Buras

Cerdà-Sevilla

et al. 2020

J. High Energ. Phys.

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We consider scenarios with a heavy Z gauge boson with flavour non-universal quark and lepton couplings with the goal to illustrate how the cancellation of gauge anomalies generated by the presence of an additional U(1) gauge symmetry would imply correlations between FCNC processes within the quark sector, within the lepton sector and most interestingly between quark flavour and lepton flavour violating processes. To this end we present simple scenarios with only left-handed flavour-violating Z couplings and those in which also right-handed flavour-violating couplings are present. The considered scenarios are characterized by a small number of free parameters but in contrast to gauge anomaly cancellation in the Standard Model, in which it takes place separately within each generation, in our scenarios anomaly cancellation involves simultaneously quarks and leptons of all three generations. Our models involve, beyond the ordinary quarks and leptons, three heavy right-handed neutrinos. The models with only left-handed FCNCs of Z involve beyond g Z and M Z two real parameters characterizing the charges of all fermions under the U(1) gauge symmetry and the CKM and PMNS ones in the quark and lepton sectors, respectively. The models with the right-handed FCNCs of Z involve few additional parameters. Imposing constraints from well measured ∆F = 2 observables we identify a number of interesting correlations that involve e.g. ε /ε, B s,d → µ + µ − , B → K(K * ) + − , K + → π + νν, K L → π 0 νν and purely lepton flavour violating decays like µ → eγ, µ → 3e, τ → 3µ and µ − e conversion among others. Also (g − 2) µ,e are considered. The impact of the experimental µ → eγ, µ → 3e and in particular µ − e conversion bounds on rare K and B decays is emphasized.

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“…The SM prediction and the current experimental measurements are [50] BR(B s → µµ) SM = (3.67 ± 0.15) × 10 −9 , For the future experimental sensitivities to B s → µµ, we assume that the central value for the branching ratio stays consistent with the current experimental value, while we take an uncertainty of ±0.16 × 10 −9 [51]. It is important to note that there is some tension (at the 2σ level) between the SM prediction and current experimental value, and assuming that the experimental central value holds there will be very significant discrepancy from future experiments.…”

Section: Constraintsmentioning

confidence: 97%

Flavorful two-Higgs-doublet models with a twist

Altmannshofer

Maddock

2018

Phys. Rev. D

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A two Higgs doublet model with flavorful Yukawa structure, in which the two doublets give mass to the third and the first two generations respectively, is combined with the twin Higgs mechanism to stabilize the Higgs mass against radiative corrections. We consider both a mirror twin and fraternal twin setup. We identify Higgs signal strength measurements and the decay B s → µµ as the most important indirect constraints on the parameter space of the model. We explore the collider phenomenology of the model and find that the heavy Higgs in the visible sector can give a sizable number of displaced decays into b-jets in regions of parameter space where the SM-like Higgs and the twin Higgs do not provide any striking signatures. I. INTRODUCTIONThe absence of clear evidence for new degrees of freedom at the electroweak scale from the Large Hadron Collider (LHC) challenges "traditional" solutions to the hierarchy problem that predict new colored degrees of freedom at the TeV scale. One elegant way to address the hierarchy problem that largely avoids constraints from direct searches at the LHC, is the twin Higgs mechanism [1] and its variations [2,3]. In the twin Higgs model the SM Higgs exists as part of an enlarged, approximately SU (4) symmetric, scalar sector. The symmetry is broken resulting in Higgs doublets both in the visible sector and in an additional "twin" sector. The original twin Higgs model prescribed a mirror symmetry, resulting in an exact copy of the SM in the twin sector (see e.g. also [4,5]). The twin fermions are not charged under the SM gauge symmetries and therefore very hard to search for experimentally. The

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B-decay discrepancies after Moriond 2019

Cited by 287 publications

References 133 publications

Complete vectorlike fourth family with U(1)′ : A global analysis

Complete vectorlike fourth family with U(1)′ : A global analysis

Quark-lepton connections in Z′ mediated FCNC processes: gauge anomaly cancellations at work

Flavorful two-Higgs-doublet models with a twist

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