Status of the global $b\to s\ell^+\ell^-$ fits

Capdevila, Bernat

doi:10.22323/1.445.0010

Cited by 3 publications

(1 citation statement)

References 49 publications

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“…Different global fits of the C 9 Wilson coefficient are shown in the bottom plot in Fig. 2.5, differing in their method and their exact experimental and theoretical inputs [17]. Overall, the C 9 fit shows a 4σ pull from the SM prediction, showing a preference for the presence of new physics.…”

Section: λ 0 B → λ + − Decaysmentioning

confidence: 99%

Decoding beauty

Greeven

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Impact paragraph Acknowledgements 2.4. Λ 0 b → Λ + − decays 2.5. Towards measuring C 9 and C 10These resonant decays are experimentally useful as they are used to validate the analysis procedure, as will be described in Chap. 4. In contrast to mesonic b → s decays, the Λ 0 b → Λ + − decays have a larger decay rate in the high q 2 region compared to the low q 2 region, allowing the search for new physics in a different, unexplored kinematic region. This is caused by the different form factors, the non-perturbative QCD effects that describe the transition between the initial and final state hadrons, of the Λ 0 b → Λ + − decays and by the difference in spin structure. The LHCb experimentThe analyses described in this thesis use data collected by the Large Hadron Collider beauty (LHCb) experiment at CERN. The LHCb experiment is located at interaction point 8 of the Large Hadron Collider (LHC). The LHC accelerates and collides proton beams (pp collisions) to a maximum of 7.5 TeV. This chapter describes the LHC and the LHCb experiment, the different LHCb subdetectors, the used trigger system, and the use of event simulation within the experiment. 3.4. Particle identification 10 MeV, which is used for the signal extraction in the physics analyses.

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Section: λ 0 B → λ + − Decaysmentioning

confidence: 99%

Decoding beauty

Greeven

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SU(2)L deconstruction and flavour (non)-universality

Capdevila,

Crivellin,

Lizana

et al. 2024

J. High Energ. Phys.

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We study two-site deconstructions of the SU(2)L gauge group factor of the SM. Models based on this approach can explain the hierarchies of the quark masses and CKM mixing between third and light families if these fields are localised on different sites by the presence of hierarchical new physics scales. The model leads to an accidental global U(2)q × U(3)u × U(3)d flavour symmetry which prevents dangerously large effects in flavour observables, making a TeV extension of the SM possible. Given the structure of the PMNS matrix in the neutrino sector, we explore different possibilities for the arrangement of the leptons on the two sites, and consider different models with U(2)ℓ or U(3)ℓ flavour symmetries. The phenomenology of the models is mostly governed by a massive vector triplet of SU(2)L. We study the interesting interplay between LHC searches and precision observables. In particular, one of the models can give a sizeable lepton flavour universal effect in the Wilson coefficient C9 while naturally suppressing contributions to C10, as suggested by current b → sℓ+ℓ− data, predicting simultaneously a mild positive shift in the W boson mass.

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Inclusive $$ \overline{B}\to {X}_s{\ell}^{+}{\ell}^{-} $$ at the LHC: theory predictions and new-physics reach

Huber,

Hurth,

Jenkins

et al. 2024

J. High Energ. Phys.

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We present theoretical predictions for observables in inclusive $$ \overline{B}\to {X}_s{\ell}^{+}{\ell}^{-} $$ B ¯ → X s ℓ + ℓ − suitable for measurements at hadron colliders through a sum-over-exclusive approach. At low q2 we calculate the branching ratio and three angular observables. At high q2 we provide the branching ratio and the ratio of the $$ \overline{B}\to {X}_s{\ell}^{+}{\ell}^{-} $$ B ¯ → X s ℓ + ℓ − rate with respect to the inclusive $$ \overline{B}\to {X}_u\ell \overline{\nu} $$ B ¯ → X u ℓ ν ¯ rate with the same phase-space cut. We compare our predictions to the B factory measurements and also to an extraction of the experimental rate through a sum-over-exclusive method using branching ratios of the exclusive $$ \overline{B}\to {K}^{\left(\ast \right)}{\mu}^{+}{\mu}^{-} $$ B ¯ → K ∗ μ + μ − modes measured at LHCb. We find a consistent picture comparing Standard Model theory and experiment. As such, our analysis does not support a recent claim about a deficit in the inclusive branching ratio in the high-q2 region. Finally, we present current model-independent bounds on new physics and emphasize the potential of complementary analyses of $$ \overline{B}\to {X}_s{\ell}^{+}{\ell}^{-} $$ B ¯ → X s ℓ + ℓ − at Belle II and the LHC.

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Status of the global $b\to s\ell^+\ell^-$ fits

Cited by 3 publications

References 49 publications

Decoding beauty

Decoding beauty

SU(2)L deconstruction and flavour (non)-universality

Inclusive $$ \overline{B}\to {X}_s{\ell}^{+}{\ell}^{-} $$ at the LHC: theory predictions and new-physics reach

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