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Study of new physics effects in B¯s→D(∗)sτ−ν¯τ semileptonic decays using lattice QCD form factors and heavy quark effective theory

Study of new physics effects in B¯s→D(∗)sτ−ν¯τ semileptonic decays using lattice QCD form factors and heavy quark effective theory
Study of new physics effects in B¯s→D(∗)sτ−ν¯τ semileptonic decays using lattice QCD form factors and heavy quark effective theory
We benefit from the lattice QCD determination of the Standard Model (SM) form factors for the B¯s→D∗s and B¯s→Ds semileptonic decays carried out by the HPQCD collaboration in Refs. Phys. Rev. D 105, 094506 (2022) and Phys. Rev. D 101, 074513 (2020), and the heavy quark effective theory (HQET) relations for the analogous B→D(∗) decays obtained by F.U. Bernlochner et al. in Phys. Rev. D 95, 115008 (2017), to extract the leading and sub-leading Isgur-Wise functions for the B¯s→D(∗)s decays. Further use of the HQET relations allows us to evaluate the corresponding scalar, pseudoscalar and tensor form factors needed for a phenomenological study of new physics (NP) effects on the B¯s→D(∗)s semileptonic decay. At present, the experimental values for the ratios RD(∗)=Γ[B¯→D(∗)τ−ν¯τ]/Γ[B¯→D(∗)e−(μ−)ν¯e(μ)] are the best signal in favor of lepton flavor universality violation (LFUV) seen in charged current (CC) b→c decays. In this work we conduct a study of NP effects on the B¯s→D(∗)sτ−ν¯τ semileptonic decays by comparing tau spin, angular and spin-angular asymmetry distributions obtained within the SM and three different NP scenarios. As expected from SU(3) light-flavor symmetry, we get results close to the ones found in a similar analysis of the B¯→D(∗) case. The measurement of the B¯s→D(∗)sℓν¯ℓ semileptonic decays, which is within reach of present experiments, could then be of relevance in helping to establish or rule out LFUV in CC b→c transitions.
hep-ph, hep-lat
1126-6708
Penalva, Neus
ae357205-4699-4ca7-b35f-b796201b7f80
Flynn, Jonathan M.
d8e90963-ba56-415c-bbd4-496b7d91d343
Hernández, Eliecer
c39107fe-f5d6-437b-89c5-aee9460a7f5f
Nieves, Juan
7d5cbd0b-f25d-44f0-be50-fdecb2e54bfe
Penalva, Neus
ae357205-4699-4ca7-b35f-b796201b7f80
Flynn, Jonathan M.
d8e90963-ba56-415c-bbd4-496b7d91d343
Hernández, Eliecer
c39107fe-f5d6-437b-89c5-aee9460a7f5f
Nieves, Juan
7d5cbd0b-f25d-44f0-be50-fdecb2e54bfe

Penalva, Neus, Flynn, Jonathan M., Hernández, Eliecer and Nieves, Juan (2024) Study of new physics effects in B¯s→D(∗)sτ−ν¯τ semileptonic decays using lattice QCD form factors and heavy quark effective theory. Journal of High Energy Physics, 2024 (163), [163]. (doi:10.48550/arXiv.2304.00250).

Record type: Article

Abstract

We benefit from the lattice QCD determination of the Standard Model (SM) form factors for the B¯s→D∗s and B¯s→Ds semileptonic decays carried out by the HPQCD collaboration in Refs. Phys. Rev. D 105, 094506 (2022) and Phys. Rev. D 101, 074513 (2020), and the heavy quark effective theory (HQET) relations for the analogous B→D(∗) decays obtained by F.U. Bernlochner et al. in Phys. Rev. D 95, 115008 (2017), to extract the leading and sub-leading Isgur-Wise functions for the B¯s→D(∗)s decays. Further use of the HQET relations allows us to evaluate the corresponding scalar, pseudoscalar and tensor form factors needed for a phenomenological study of new physics (NP) effects on the B¯s→D(∗)s semileptonic decay. At present, the experimental values for the ratios RD(∗)=Γ[B¯→D(∗)τ−ν¯τ]/Γ[B¯→D(∗)e−(μ−)ν¯e(μ)] are the best signal in favor of lepton flavor universality violation (LFUV) seen in charged current (CC) b→c decays. In this work we conduct a study of NP effects on the B¯s→D(∗)sτ−ν¯τ semileptonic decays by comparing tau spin, angular and spin-angular asymmetry distributions obtained within the SM and three different NP scenarios. As expected from SU(3) light-flavor symmetry, we get results close to the ones found in a similar analysis of the B¯→D(∗) case. The measurement of the B¯s→D(∗)sℓν¯ℓ semileptonic decays, which is within reach of present experiments, could then be of relevance in helping to establish or rule out LFUV in CC b→c transitions.

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2304.00250v1 - Author's Original
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JHEP01(2024)163 - Version of Record
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More information

Submitted date: 1 April 2023
Accepted/In Press date: 15 January 2024
e-pub ahead of print date: 25 January 2024
Keywords: hep-ph, hep-lat

Identifiers

Local EPrints ID: 478167
URI: http://eprints.soton.ac.uk/id/eprint/478167
ISSN: 1126-6708
PURE UUID: d6dc3cc1-dc32-42f3-b630-3b9e63fc46aa
ORCID for Jonathan M. Flynn: ORCID iD orcid.org/0000-0002-6280-1677

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Date deposited: 23 Jun 2023 16:38
Last modified: 17 May 2024 01:33

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Contributors

Author: Neus Penalva
Author: Eliecer Hernández
Author: Juan Nieves

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