Derives the full two-loop ADM for four-fermion operators in LEFT in NDR scheme including O(α_s²), O(α_s α) and O(α²) terms, with results for 5/4/3 active flavors implemented in DsixTools.
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Weak Decays Beyond Leading Logarithms
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abstract
We review the present status of QCD corrections to weak decays beyond the leading logarithmic approximation including particle-antiparticle mixing and rare and CP violating decays. After presenting the basic formalism for these calculations we discuss in detail the effective hamiltonians for all decays for which the next-to-leading corrections are known. Subsequently, we present the phenomenological implications of these calculations. In particular we update the values of various parameters and we incorporate new information on m_t in view of the recent top quark discovery. One of the central issues in our review are the theoretical uncertainties related to renormalization scale ambiguities which are substantially reduced by including next-to-leading order corrections. The impact of this theoretical improvement on the determination of the Cabibbo-Kobayashi-Maskawa matrix is then illustrated in various cases.
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representative citing papers
Spin-flavor entanglement in Lambda_b to Lambda D decays supplies a method to extract the CKM weak phase gamma with uncertainty scaling as 1 over the Wootters concurrence.
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 symmetry-guided phenomenological model organizes leading current-current operators for charged-current decays of heavy-light mesons and reproduces heavy-quark scaling relations for decay constants and form factors.
A quark-lepton unified Pati-Salam model with Z2 symmetry realizes a leptoquark gauge boson as light as 4.3 TeV, compatible with LHC and flavor constraints, and predicts testable lepton flavor violation plus new vector-like quarks.
Computes branching ratios of order 10^{-10} for Bs and 10^{-11} for Bd decays after NLO vertex corrections in QCD factorization, plus dimuon distributions and J/psi polarization.
Doubly charmed baryon decays provide symmetry-protected null tests for nonfactorizable QCD and lepton-universality ratios sensitive to new physics at multi-TeV scales.
A reweighting method creates model-agnostic likelihoods from histogram analyses, applied to Belle II B+ to K+ nu nubar data for WET constraints and light new physics searches.
Including resonant contributions from LHCb muon data enhances standard model predictions for B to K(*) tau tau decays and makes short-distance new physics comparable to or larger than resonant effects over the full q2 range.
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.
Computes pQCD form factors for B_c to D(*) transitions via lattice inputs and heavy quark symmetry, then predicts branching fractions and angular observables for semileptonic and rare dilepton decays.
Updated predictions within the heavy quark expansion confirm the lifetime hierarchy τ(Ξ_cc^+) < τ(Ω_cc^+) < τ(Ξ_cc^++) with τ(Ξ_cc^++) = 0.32 ± 0.05 +0.08/-0.07 ps matching LHCb data and provide ratios for the other states.
Updated lifetime predictions for doubly heavy baryons and B_c meson with NNLO and NLO corrections in MS-bar, kinetic, and Upsilon mass schemes, including new hierarchies for bc states.
In minimal benchmarks with a vector-like down quark D and singlet scalar, the new-physics contribution to B to X_s gamma is only 0.4 percent of the Standard Model value at TeV scales, while B_s mixing imposes stronger limits on the complex-scalar case.
The CP-violating decay-rate asymmetry in Σ⁺→pℓ⁺ℓ⁻ is allowed to reach tens of percent and is testable at LHCb.
A data-driven SU(3)-breaking analysis of B to PP decays yields QCD-factorization amplitudes that resemble dynamical predictions and require no enhanced annihilation terms.
Lifetimes of Xi_cc++, Xi_cc+, Omega_cc+ are (2.67 ± 0.94, 0.47 ± 0.08, 1.79 ± 0.62) × 10^{-13} s and for Xi_bb0, Xi_bb-, Omega_bb- are (0.75 ± 0.11, 0.92 ± 0.15, 0.93 ± 0.15) × 10^{-12} s, with W-exchange driving large splittings in the charmed sector.
Rescattering enhances the anti-D0 Lambda branching fraction by two orders of magnitude and produces large direct CP asymmetries (0.28 and -0.14) in Lambda_b to Lambda D channels.
The LRIS model explains the B→Kμμ anomaly with ΔC9 ≈ -1 and ΔC10 ≈ 0 through a non-decoupling box diagram while suppressing Bs mixing via GIM-like phases and satisfying constraints.
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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CP asymmetries for B+ to pi+ pi0, D+ to pi+ pi0, and K+ to pi+ pi0 are estimated in the Standard Model at roughly 3 times 10 to the -3, 10 to the -5, and 10 to the -6 using a unified formalism for isospin violation.
The Left-Right Inverse Seesaw model generates a non-decoupling scalar operator that enhances the differential forward-backward CP asymmetry A_CP^FB(s) near K* and K0* resonances in τ → Kπν_τ while leaving the integrated asymmetry too small to explain the BaBar result.
citing papers explorer
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Null Tests and Lepton Universality in $\Xi_{cc}$ Baryon Decays
Doubly charmed baryon decays provide symmetry-protected null tests for nonfactorizable QCD and lepton-universality ratios sensitive to new physics at multi-TeV scales.
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CP violation in $\Sigma^+\to p\ell^+\ell^-$ within the standard model and beyond
The CP-violating decay-rate asymmetry in Σ⁺→pℓ⁺ℓ⁻ is allowed to reach tens of percent and is testable at LHCb.
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Study of doubly heavy baryon lifetimes
Lifetimes of Xi_cc++, Xi_cc+, Omega_cc+ are (2.67 ± 0.94, 0.47 ± 0.08, 1.79 ± 0.62) × 10^{-13} s and for Xi_bb0, Xi_bb-, Omega_bb- are (0.75 ± 0.11, 0.92 ± 0.15, 0.93 ± 0.15) × 10^{-12} s, with W-exchange driving large splittings in the charmed sector.