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Soft photon corrections in B → K(∗)+- and Λb → Λ(∗)+- decays

2023/07/14 by Debajyoti Choudhury, Choudhury, Debajyoti, Diganta Das +3
Computer Science · Physics and Astronomy · #Computational Physics and Python Applications #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions

paper · pdf · doi:10.48550/arxiv.2307.07578

openalex publication_date 2023/07/14 · openalex created_date 2023/07/19 · openalex updated_date 2026/07/28

Abstract

We calculate QED corrections to the semileptonic decays H1 → H2+- where ℓ=e, μ and H1,2 are hadrons. The soft and/or collinear divergences are regulated in a gauge-invariant manner and demonstrably cancel, leaving behind a finite residue that depends on the (infrared) momentum cutoff below which a photon is considered to be indistinguishable. On resuming, the said sensitivity reduces drastically, i.e., for the NLL result as compared to the NLO one. The overall correction is negative and its magnitude is larger for a lighter lepton. For B → K(*) decays, the corrections improve the agreement for the differential distributions, while the behavior is more complicated for Λb → Λ(*) decays. Rather intriguingly, the corrections serve to regenerate the tension for the lepton flavor universality observables RK and RK^*.

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