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The updated analysis of the LHCb Collaboration on the lepton flavor violation suggests that the new physics should couple to muons and electrons with comparable magnitudes, resulting in the anomalies in both rare decay channels, $b…

High Energy Physics - Phenomenology · Physics 2023-11-13 Sang Quang Dinh , Hieu Minh Tran

The LHCb measurement of the $\mu/e$ ratio $R_{K^*}$ indicates a deficit with respect to the Standard Model prediction, supporting earlier hints of lepton universality violation observed in the $R_K$ ratio. We show that the $R_K$ and…

High Energy Physics - Phenomenology · Physics 2019-03-26 Guido D'Amico , Marco Nardecchia , Paolo Panci , Francesco Sannino , Alessandro Strumia , Riccardo Torre , Alfredo Urbano

The measurements of the lepton flavor universality (LFU) in $\mathcal{B}({\bar{B}} \to D^{(\ast)} l \bar{\nu})$ indicate a significant deviation from the standard model prediction at a 3-4$\sigma$ level, revealing a violation of the LFU…

High Energy Physics - Phenomenology · Physics 2024-10-15 Syuhei Iguro , Teppei Kitahara

We sketch a novel method to search for light di-leptonic resonances by exploiting precision measurements of Drell-Yan production. Motivated by the recent hints of lepton flavour universality violation in $B \to K^{\ast} \ell^+ \ell^-$, we…

High Energy Physics - Phenomenology · Physics 2017-09-13 Fady Bishara , Ulrich Haisch , Pier Francesco Monni

Within the assumption of Left-Handed (LH) New Physics (NP), we review the relations between $\mathcal{B}(B\to K^{(\ast)} \tau^+\tau^-)$ and $\mathcal{B}(B\to K^{(\ast)} \nu\bar \nu)$ for several Beyond the Standard Model (BSM) scenarios,…

High Energy Physics - Phenomenology · Physics 2022-11-11 Arturo de Giorgi , Gioacchino Piazza

We analyze lepton flavour violating transitions, leptonic magnetic dipole moments (MDMs) and electric dipole moments (EDMs) in a class of models characterized by the flavour symmetry A4 x Z3 x U(1)_{FN}, whose choice is motivated by the…

High Energy Physics - Phenomenology · Physics 2008-12-18 Ferruccio Feruglio , Claudia Hagedorn , Yin Lin , Luca Merlo

We study the lepton flavor violation (LFV), the leptonic magnetic moments $(g-2)_{\mu,\,e} $ and the electric dipole moment (EDM) of the electron in the Standard-Model Effective Field Theory with the $\Gamma_N$ modular flavor symmetry. We…

High Energy Physics - Phenomenology · Physics 2022-08-24 Tatsuo Kobayashi , Hajime Otsuka , Morimitsu Tanimoto , Kei Yamamoto

The observable $\mathcal{R} \left( D^{(*)} \right) = \mathcal{B}\left( B^{0}\to D^{(*)-} \tau^{+} \nu_{\tau} \right) / \mathcal{B}\left( B^{0}\to D^{(*)-} \mu^{+} \nu_{\mu} \right)$ is a probe for Lepton Universality violation, so it is…

High Energy Physics - Experiment · Physics 2019-08-14 Federico Betti

We consider an abelian extension of the Standard Model (SM) comprising a new gauge group $U(1)^\prime$, with the neutral gauge boson $Z^\prime$ having flavour violating couplings to quarks and leptons. The fermion content is the same as in…

High Energy Physics - Phenomenology · Physics 2025-11-27 Pietro Colangelo , Fulvia De Fazio , Davide Milillo

The current world averages of the ratios $R_{D^{(*)}}$ are about $4\sigma$ away from their Standard Model prediction. These measurements indicate towards the violation of lepton flavor universality in $b\rightarrow c\,l\,\bar{\nu}$ decay.…

High Energy Physics - Phenomenology · Physics 2020-02-18 Suman Kumbhakar , Ashutosh Kumar Alok , Dinesh Kumar , S Uma Sankar

Flavour physics plays a crucial role in the search for physics beyond the Standard Model (SM). While $B$ physics offers many observables to look for deviations from the SM, the highest new physics sensitivity can be obtained in the rare…

High Energy Physics - Phenomenology · Physics 2014-12-03 Monika Blanke

The LHCb measurements of the $\mu / e$ ratio in $B \to K \ell \ell$ decays $(R_{K^{}})$ indicate a deficit with respect to the Standard Model prediction, supporting earlier hints of lepton universality violation observed in the…

High Energy Physics - Phenomenology · Physics 2022-01-12 Guo-yuan Huang , Sudip Jana , Farinaldo S. Queiroz , Werner Rodejohann

The persistent deviations observed in semileptonic $B$ decays, in particular the lepton flavor universality ratios $\mathcal{R}(D^{(*)})$ and $\mathcal{R}(\Lambda_c)$, provide intriguing hints of physics beyond the Standard Model (SM).…

High Energy Physics - Phenomenology · Physics 2025-10-14 Dris Boubaa , Shaaban Khalil

Experimental hints for lepton-flavor universality violation in the muon's magnetic moment as well as neutral- and charged-current $B$-meson decays require Standard-Model extensions by particles such as leptoquarks that generically lead to…

High Energy Physics - Phenomenology · Physics 2022-05-26 Julian Heeck , Anil Thapa

We discuss a minimal solution to the long-standing $(g-2)_\mu$ anomaly in a simple extension of the Standard Model with an extra $Z'$ vector boson that has only flavor off-diagonal couplings to the second and third generation of leptons,…

High Energy Physics - Phenomenology · Physics 2016-10-21 Wolfgang Altmannshofer , Chien-Yi Chen , P. S. Bhupal Dev , Amarjit Soni

In supersymmetric extensions of the Standard Model, the lepton flavour violation (LFV) is closely related to the structure of slepton masses and mixing. Allowing for the most general flavour structure of the slepton sector, consistent with…

High Energy Physics - Phenomenology · Physics 2007-05-23 Jan Kalinowski

Lepton flavor violation (LFV), observed conclusively in neutrino oscillations, remains a pivotal area of investigation due to its absence in the Standard Model (SM). Beyond the Standard Model (BSM) physics explores charged lepton flavor…

High Energy Physics - Phenomenology · Physics 2024-10-29 Jia Liu , Muyuan Song , Haohao Zhang

The phenomenon of CP violation in the standard model (SM) framework and the decay dynamics have been established from the data obtained from the B factories and so far we have not seen anything new. Nevertheless, there have been instances…

High Energy Physics - Phenomenology · Physics 2017-01-04 A. Giri , R. Mohanta , S. Sahoo

In view of the emerging hints for the violation of lepton flavour universality in several $B$-meson decays, we conduct a model-independent study (effective field theory approach) of several well-motivated new physics scenarios. Taking into…

High Energy Physics - Phenomenology · Physics 2021-04-02 J. Kriewald , C. Hati , J. Orloff , A. M. Teixeira

The discovery of neutrino oscillation, proving that neutrinos do have masses, reveals the misfits of particles in the current Standard Model (SM) theory. In theory, neutrinos having masses could result in lepton flavour not being a symmetry…

High Energy Physics - Phenomenology · Physics 2022-06-14 Reymond Mesuga