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Publication . Preprint . 2017

Correlating Lepton Flavour (Universality) Violation in $B$ Decays with $\mu\to e\gamma$ using Leptoquarks

Crivellin, Andreas; Mueller, Dario; Signer, Adrian; Ulrich, Yannick;
Open Access   English  
Published: 26 Jun 2017
Motivated by the measurements of $b\to s\ell^+\ell^-$ transitions, including $R(K)$ and $R(K^*)$, we examine lepton flavour (universality) violation in $B$ decays and its connections to $\mu\to e\gamma$ in generic leptoquark models. Considering all 10 representations of scalar and vector leptoquarks under the Standard Model gauge group we compute the tree-level matching for semileptonic $b$-quark operators as well as their loop effects in $\ell\to\ell^\prime\gamma$. In our phenomenological analysis we correlate $R(K)$, $R(K^*)$ and the other $b\to s\mu^+\mu^-$ data to $\mu\to e\gamma$ and $b\to s\mu e$ transitions for the three leptoquark representations that generate left-handed currents in $b\to s\ell^+\ell^-$ transitions and, therefore, provide a good fit to data. We find that while new physics contributions to muons are required by the global fit, also couplings to electrons can be sizeable without violating the stringent bounds from $\mu\to e\gamma$. In fact, if the effect in electrons in $b\to s\ell^+\ell^-$ has opposite sign than the effect in muons the bound from $\mu\to e\gamma$ can always be avoided. However, unavoidable effects in $b\to s\mu e$ transitions (i.e. $B_s\to\mu e$, $B\to K\mu e$, etc.) appear which are within the reach of LHCb and BELLE II.
Comment: 17 pages, 2 figures and 5 tables, version accepted for publication in PRD
Subjects by Vocabulary

arXiv: High Energy Physics::Experiment High Energy Physics::Phenomenology


High Energy Physics - Phenomenology, High Energy Physics - Experiment

50 references, page 1 of 5

[5] B. Capdevila, A. Crivellin, S. Descotes-Genon, J. Matias, and J. Virto (2017), 1704.05340.

[6] Y. Amhis et al. (2016), 1612.07233.

[7] B. Gripaios, M. Nardecchia, and S. Renner, JHEP 1505, 006 (2015), 1412.1791.

[8] S. Fajfer and N. Koˇsnik, Phys. Lett. B755, 270 (2016), 1511.06024.

[9] D. Becirevic, S. Fajfer, and N. Kosnik (2015), 1503.09024.

[10] I. d. M. Varzielas and G. Hiller (2015), 1503.01084.

[11] R. Alonso, B. Grinstein, and J. M. Camalich (2015), 1505.05164.

[12] L. Calibbi, A. Crivellin, and T. Ota, Phys. Rev. Lett. 115, 181801 (2015), 1506.02661.

[13] R. Barbieri, G. Isidori, A. Pattori, and F. Senia, Eur. Phys. J. C76, 67 (2016), 1512.01560.

[14] D. Becirevic, N. Kosnik, O. Sumensari, and R. Zukanovich Funchal, JHEP 11, 035 (2016), 1608.07583.

Funded by
SNSF| Muon Decays
  • Funder: Swiss National Science Foundation (SNSF)
  • Project Code: 200021_163466
  • Funding stream: Project funding | Project funding (Div. I-III)
SNSF| Flavour Physics beyond the Standard Model
  • Funder: Swiss National Science Foundation (SNSF)
  • Project Code: PZ00P2_154834
  • Funding stream: Careers | Ambizione
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