B-decay anomalies in Pati–Salam SU(4)

Barbieri, Riccardo; Tesi, Andrea

doi:10.1140/epjc/s10052-018-5680-9

Cited by 136 publications

(117 citation statements)

References 83 publications

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“…As pointed out in [19], the presence of (at least) these additional states is a general feature of any UV completion of a flavor non-universal U 1 . These states are indeed present also in UV completions based on new strongly interacting dynamics [20,21].…”

Section: Introductionmentioning

confidence: 71%

Vector leptoquarks beyond tree level

et al. 2020

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Models with massive vector leptoquarks, resulting from an SU (4) gauge symmetry spontaneously broken at the TeV scale, are of great phenomenological interest given the current "anomalies" in semileptonic B decays. We analyze the relations between low-and high-energy observables in such class of models to next-to-leading order accuracy in the SU (4) gauge coupling g4. For large values of g4, motivated by recent B-physics data, one-loop corrections are sizeable. The main effect is an enhanced contribution at low-energy, at fixed on-shell couplings. This result has important implications for current and future high-energy searches of vector leptoquark models.

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Section: Introductionmentioning

confidence: 71%

Vector leptoquarks beyond tree level

et al. 2020

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“…As an illustration of the method, we consider in detail the minimally extended MFV scenario that accounts for the present flavour anomalies. Since one of the most promising setups to fit the anomalies is a U 1 leptoquark model [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40], one simply needs to consider the spurions which are associated with the fermion currents that the U 1 leptoquark is coupling to (see below). These spurions will be referred to as ∆ QL and ∆ DE in the following.…”

Section: Introductionmentioning

confidence: 99%

Effective theory approach to new physics with flavour: general framework and a leptoquark example

Bordone

Catà

Feldmann

2020

J. High Energ. Phys.

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Extending the Standard Model with higher-dimensional operators in an effective-fieldtheory (EFT) approach provides a systematic framework to study new-physics (NP) effects from a bottom-up perspective, as long as the NP scale is sufficiently large compared to the energies probed in the experimental observables. However, when taking into account the different quark and lepton flavours, the number of free parameters increases dramatically, which makes generic studies of the NP flavour structure infeasible. In this paper, we address this issue in view of the recently observed "flavour anomalies" in B-meson decays, which we take as a motivation to develop a general framework that allows us to systematically reduce the number of flavour parameters in the EFT. This framework can be easily used in global fits to flavour observables at Belle II and LHCb as well as in analyses of flavour-dependent collider signatures at the LHC. Our formalism represents an extension of the well-known minimal-flavour-violation approach, and uses Froggatt-Nielsen charges to define the flavour power-counting. As a relevant illustration of the formalism, we apply it to the flavour structures which could be induced by a U 1 vector leptoquark, which represents one of the possible explanations for the recent hints of flavour non-universality in semileptonic B-decays. We study the phenomenological viability of this specific framework performing a fit to low-energy flavour observables.

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“…Furthermore, also RðJ=ΨÞ points towards the violation of LFU in b → cτν processes [10]. This suggests a possible connection between these two classes of decays and motivates the investigation of simultaneous explanations [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30].…”

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confidence: 99%

“…This allows for large flavor violating effects and the bounds from direct searches [32], and electroweak (EW) precision data [33,34] can be avoided [24,27]. Interestingly, this LQ appears in the theoretically very appealing Pati-Salam (PS) [35] model, and several attempts have been made in the literature to construct a model addressing the flavor anomalies based on the corresponding gauge symmetry [28][29][30]36].…”

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confidence: 99%

B Meson Anomalies in a Pati-Salam Model within the Randall-Sundrum Background

2018

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Lepton number as a fourth color is the intriguing theoretical idea of the famous Pati-Salam (PS) model. While in conventional PS models, the symmetry breaking scale and the mass of the resulting vector leptoquark are stringently constrained by K L → μe and K → πμe, the scale can be lowered to a few TeV by adding vectorlike fermions. Furthermore, in this case, the intriguing hints for lepton flavor universality violation in b → sμ þ μ − and b → cτν processes can be addressed. Such a setup is naturally achieved by implementing the PS gauge group in the five-dimensional Randall-Sundrum background. The PS symmetry is broken by boundary conditions on the fifth dimension, and the resulting massive vector leptoquark automatically has the same mass scale as the vectorlike fermions and all other resonances. We consider the phenomenology of this model in the context of the hints for lepton flavor universality violation in semileptonic B decays. Assuming flavor alignment in the down sector, we find that in b → sl þ l − transitions, the observed deviations from the standard model predictions [including RðKÞ and RðK Ã Þ can be explained with natural values for the free parameters of the model. Even though we find sizable effects in RðDÞ, RðD Ã Þ, and RðJ=ΨÞ, one cannot account for the current central values in the constrained setup of our minimal model due to the stringent constraints from D −D mixing and τ → 3μ.

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B-decay anomalies in Pati–Salam SU(4)

Cited by 136 publications

References 83 publications

Vector leptoquarks beyond tree level

Vector leptoquarks beyond tree level

Effective theory approach to new physics with flavour: general framework and a leptoquark example

B Meson Anomalies in a Pati-Salam Model within the Randall-Sundrum Background

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