LHCb reports the first upper limits on B0 → K+π−τ+τ− and Bs0 → K+K−τ+τ− branching fractions, with recast limits of 2.8×10−4 on B0 → K*(892)0 τ+τ− at 95% CL that improve prior bounds by an order of magnitude.
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$B\to V\ell^+\ell^-$ in the Standard Model from Light-Cone Sum Rules
14 Pith papers cite this work. Polarity classification is still indexing.
abstract
We present $B_q\to\rho$, $B_q\to\omega$, $B_q\to K^*$, $B_s\to K^*$ and $B_s\to \phi$ form factors from light-cone sum rules (LCSR) at $\mathcal{O}(\alpha_s)$ for twist-2 and 3 and $\mathcal{O}(\alpha_s^0)$ for twist-4 with updated hadronic input parameters. Three asymptotic light-cone distribution amplitudes of twist-$4$ (and $5$) are determined, necessary for the form factors to obey the equations of motion. It is argued that the latter constrain the uncertainty of tensor-to-vector form factor ratios thereby improving the prediction of zeros of helicity amplitudes of major importance for $B\to K^*\ell\ell$ angular observables. We provide easy-to-use fits to the LCSR results, including the full error correlation matrix, in all modes at low $q^2$ as well as combined fits to LCSR and lattice results covering the entire kinematic range for $B_q\to K^*$, $B_s\to K^*$ and $B_s\to \phi$. The error correlation matrix avoids the problem of overestimating the uncertainty in phenomenological applications. Using the new form factors and recent computations of non-factorisable contributions we provide Standard Model predictions for $B\to K^*\gamma$ as well as $B\to K^*\ell^+\ell^-$ and $B_s\to\phi\mu^+\mu^-$ at low dilepton invariant mass. Employing our $B \to (\rho,\omega) $ form factor results we extract the CKM element $|V_\mathrm{ub}|$ from the semileptonic decays $B\to(\rho,\omega) \ell\nu$ and find good agreement with other exclusive determinations.
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Ratios of exclusive to inclusive b to s lepton lepton observables discriminate between new physics and constant hadronic effects, with current data favoring new physics.
A single nearly degenerate dark matter multiplet in the MFV framework can accommodate either the K+ to pi+ nu nubar or B+ to K+ nu nubar excess but not both simultaneously.
Perturbative QCD calculations find that branching fractions for Ξ_b to Ξ lepton-pair decays lie within LHCb reach and that angular observables plus a specific ratio can constrain Wilson coefficients and extract |V_td/V_ts| independently of mesonic modes.
Belle II data on the rare B decay constrains the non-minimal UED model to require the inverse compactification radius to be at least ~900 GeV, while the minimal version yields no bound.
Scalar and vector dark-matter mediator scenarios in B decays are distinguishable via differential distributions, with data imposing M_V ≲ 3 GeV for vectors but no mass bound for scalars.
SMEFT global fit to b→s anomalies with complex Wilson coefficients shows left-handed four-fermion operators preferred and demonstrates that U(3)^5 or U(2)^5 flavor symmetry restores consistency with kaon data.
Final-state rescattering predicts branching fractions for B0 and Bs0 to Lambda_c+ anti-Lambda_c- that match LHCb data, with near-zero CP asymmetries and sizable longitudinal polarization in the B0 channel.
Predictions for Br(Λ_b → Λ^{(*)} ν ν̄) are 2.07 times the SM value with new physics scale constrained to 2.04–11.76 TeV at 1σ, plus a sum rule linking baryonic and mesonic modes.
Belle-II excess in B to K/K* + missing energy is explained by dark matter fermion pair production via scalar or vector mediator, with discrimination possible through decay rate inspections.
Perturbative symmetry-breaking corrections shift the branching ratio and normal lepton polarization asymmetry by ~3% in B → K0*(1430) μ+μ−, so larger experimental deviations would indicate new physics.
LHCb reports updated FCNC decay measurements including a legacy analysis of B0 to K*0 mu+ mu- using 8.4 fb-1 of Run 1 and 2 data, noting persistent tensions with SM expectations in b to s mu mu channels.
Updated type-I seesaw analysis shows semileptonic tau decays like tau to lepton rho can dominate cLFV signals and some branching ratios may reach next-generation experiment sensitivity.
Model-independent calculation of differential branching ratio, forward-backward asymmetry, polarization, and angular coefficients in Bs → K* μ+μ- with 1D and 2D new physics scenarios in C7^NP, C9^(prime)NP, and C10^(prime)NP showing deviations from SM.
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Searches for $B^0\to K^+\pi^-\tau^+\tau^-$ and $B_s^0\to K^+K^-\tau^+\tau^-$ decays
LHCb reports the first upper limits on B0 → K+π−τ+τ− and Bs0 → K+K−τ+τ− branching fractions, with recast limits of 2.8×10−4 on B0 → K*(892)0 τ+τ− at 95% CL that improve prior bounds by an order of magnitude.
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Probing unknown nonperturbative effects in $b \to s \ell\ell$ with inclusive and exclusive observables
Ratios of exclusive to inclusive b to s lepton lepton observables discriminate between new physics and constant hadronic effects, with current data favoring new physics.
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A single nearly degenerate dark matter multiplet in the MFV framework can accommodate either the K+ to pi+ nu nubar or B+ to K+ nu nubar excess but not both simultaneously.
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Semileptonic neutral current decays of $\Xi_b$ with dileptons or dineutrinos in the final state
Perturbative QCD calculations find that branching fractions for Ξ_b to Ξ lepton-pair decays lie within LHCb reach and that angular observables plus a specific ratio can constrain Wilson coefficients and extract |V_td/V_ts| independently of mesonic modes.
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Belle II Constraints on the Non-Minimal Universal Extra Dimensional Model
Belle II data on the rare B decay constrains the non-minimal UED model to require the inverse compactification radius to be at least ~900 GeV, while the minimal version yields no bound.
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Probing vector- vs scalar-mediator dark-matter scenarios in $B\to (K,K^*) M_X$ decays
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Correlated $b \to s$ and $s \to d$ Rare Semileptonic Transitions in the Standard Model Effective Field Theory
SMEFT global fit to b→s anomalies with complex Wilson coefficients shows left-handed four-fermion operators preferred and demonstrates that U(3)^5 or U(2)^5 flavor symmetry restores consistency with kaon data.
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Final-state rescattering in $\bar{B}^{0}_{(s)}\to \Lambda^{+}_{c}\bar{\Lambda}^{-}_{c}$ decays
Final-state rescattering predicts branching fractions for B0 and Bs0 to Lambda_c+ anti-Lambda_c- that match LHCb data, with near-zero CP asymmetries and sizable longitudinal polarization in the B0 channel.
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$\Lambda_b\to\Lambda^{(*)}\nu{\bar\nu}$ and $b\to s$ $B$ decays
Predictions for Br(Λ_b → Λ^{(*)} ν ν̄) are 2.07 times the SM value with new physics scale constrained to 2.04–11.76 TeV at 1σ, plus a sum rule linking baryonic and mesonic modes.
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Analysis of $B\to KM_X$ and $B\to K^* M_X$ decays in scalar- and vector-mediator dark-matter scenarios
Belle-II excess in B to K/K* + missing energy is explained by dark matter fermion pair production via scalar or vector mediator, with discrimination possible through decay rate inspections.
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Symmetry-Breaking Effects on Form Factors and Observables in $B \to K_0^*(1430)\mu^+\mu^-$ Decay
Perturbative symmetry-breaking corrections shift the branching ratio and normal lepton polarization asymmetry by ~3% in B → K0*(1430) μ+μ−, so larger experimental deviations would indicate new physics.
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Flavour Changing Neutral Current decays at LHCb
LHCb reports updated FCNC decay measurements including a legacy analysis of B0 to K*0 mu+ mu- using 8.4 fb-1 of Run 1 and 2 data, noting persistent tensions with SM expectations in b to s mu mu channels.
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Revisiting lepton flavor violation: $\tau$ and meson decays
Updated type-I seesaw analysis shows semileptonic tau decays like tau to lepton rho can dominate cLFV signals and some branching ratios may reach next-generation experiment sensitivity.
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Investigating New Physics through the Observables of Semileptonic $B_{s}\to K^{\ast}(\to K \pi)\mu^{+}\mu^{-}$ Decay
Model-independent calculation of differential branching ratio, forward-backward asymmetry, polarization, and angular coefficients in Bs → K* μ+μ- with 1D and 2D new physics scenarios in C7^NP, C9^(prime)NP, and C10^(prime)NP showing deviations from SM.