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Related papers: $R_K$ and future $b \to s \ell \ell$ BSM opportuni…

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The latest measurements of rare $b\to s$ decays in the LHCb experiment have led to results in tension with the predictions of the standard model (SM), including a tentative indication of the violation of lepton flavor universality. Assuming…

High Energy Physics - Phenomenology · Physics 2015-08-31 Chao-Jung Lee , Jusak Tandean

Motivated by the recent LHCb announcement of a $3.1\sigma$ violation of lepton-flavor universality in the ratio $R_K=\Gamma(B\to K\mu^+\mu^-)/\Gamma(B\to K e^+ e^-)$, we present an updated, comprehensive analysis of the flavor anomalies…

High Energy Physics - Phenomenology · Physics 2021-09-28 Claudia Cornella , Darius A. Faroughy , Javier Fuentes-Martin , Gino Isidori , Matthias Neubert

Measurements of the ratio of $B \to K^* \mu \mu $ to $B \to K^* e e $ branching fractions, $R_{K^*}$, by the LHCb collaboration strengthen the hints from previous studies with pseudoscalar kaons, $R_K$, for the breakdown of lepton…

High Energy Physics - Phenomenology · Physics 2018-02-12 Gudrun Hiller , Ivan Nisandzic

The measurement of lepton universality parameters $R_{K^{(*)}}$ was updated by LHCb in December 2022, which indicated that the well-known anomalies in flavor-changing neutral current (FCNC) processes of B meson decays have faded away.…

High Energy Physics - Phenomenology · Physics 2023-10-31 Qiaoyi Wen , Fanrong Xu

Flavor symmetries successfully explain lepton and quark masses and mixings yet it is usually hard to distinguish different models that predict the same mixing angles. Further experimental input could be available, if the agents of flavor…

High Energy Physics - Phenomenology · Physics 2015-09-03 Ivo de Medeiros Varzielas , Gudrun Hiller

The flavor-changing neutral current semileptonic decays of $B$ mesons provide an excellent platform for indirectly probing New Physics (NP) beyond the Standard Model (SM). Recent measurements of lepton flavor universality (LFU) ratios such…

High Energy Physics - Phenomenology · Physics 2026-01-08 Md Isha Ali , Utpal Chattopadhyay , Dilip Kumar Ghosh , N Rajeev

Even though the LHC searches did not unveil the new physics particles so far, LHCb hints towards deviations from lepton flavor universality in exclusive decays based on the transition $b\to s\ell\ell$. In this proceeding, we present a new…

High Energy Physics - Phenomenology · Physics 2017-10-25 Olcyr Sumensari

Ratios of branching fractions of semileptonic B decays, $(B \to H \mu \mu)$ over $(B \to H ee)$ with $H=K, K^*,X_s, K_0(1430), \phi, \ldots$ are sensitive probes of lepton universality. In the Standard Model, the underlying flavor changing…

High Energy Physics - Phenomenology · Physics 2015-06-23 Gudrun Hiller , Martin Schmaltz

The ratio of the measured $\bar B\to D^{(*)}\ell\bar{\nu}$ decay rates for $\ell = \tau$ vs. $e,\mu$ deviate from the Standard Model (SM) by about $4\sigma$. We show that the data are in tension with the SM, independent of form factor…

High Energy Physics - Phenomenology · Physics 2017-10-17 Marat Freytsis , Zoltan Ligeti , Joshua T. Ruderman

Flavour Changing Neutral Current (FCNC) decays are forbidden at lowest perturbative order in the Standard Model (SM) and only allowed via quantum loops. These transitions are therefore heavily suppressed in the SM, and New Physics (NP) can…

High Energy Physics - Experiment · Physics 2026-05-19 Christoph Langenbruch

One of the fundamental predictions of the Standard Model is Lepton Flavour Universality. Any deviation from this prediction would indicate the existence of physics beyond the Standard Model. Recent LHCb measurements present a pattern of…

High Energy Physics - Phenomenology · Physics 2018-08-21 Yoav Afik , Jonathan Cohen , Eitan Gozani , Enrique Kajomovitz , Yoram Rozen

Tension between the Standard Model (SM) and data concerning $b \rightarrow s$ processes has become apparent. Most notoriously, concerning the $R_K$ ratio, which probes lepton non-universality in $b$ decays, and measurements involving the…

High Energy Physics - Phenomenology · Physics 2017-03-30 Isabel Garcia Garcia

Present measurements of b->c tau nu and b->u tau nu transitions differ from the standard model predictions of lepton flavor universality by almost 4sigma. We examine new physics interpretations of this anomaly. An effective field theory…

High Energy Physics - Phenomenology · Physics 2013-01-04 Svjetlana Fajfer , Jernej F. Kamenik , Ivan Nisandzic , Jure Zupan

The long persistent discrepancies in $b\,\to\,s\, \ell\, \ell$ quark level transitions continue to be the ideal platform for an indirect search of new physics that lies beyond the SM. The measurements of $R_K$, $R_{K^*}$, $P_5^{\prime}$,…

High Energy Physics - Phenomenology · Physics 2023-09-07 N Rajeev , Rupak Dutta

At present, there are several hints of lepton flavor non-universality. The LHCb Collaboration has measured $R_K\equiv{\cal B}(B^+ \to K^+ \mu^+ \mu^-)/{\cal B}(B^+ \to K^+ e^+ e^-)$, and the BaBar Collaboration has measured $R(D^{(*)})…

High Energy Physics - Phenomenology · Physics 2015-02-17 Bhubanjyoti Bhattacharya , Alakabha Datta , David London , Shanmuka Shivashankara

The $B$-physics experiments at LHCb, BaBar and Belle hint towards deviations from Lepton Flavor Universality in both the tree-level and loop-induced $B$ meson semileptonic decays. We propose a leptoquark model with light right-handed…

High Energy Physics - Phenomenology · Physics 2017-05-23 Olcyr Sumensari

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 LHCb measurements of certain ratios of decay modes testing lepton flavour non-universality might open an exciting world of new physics beyond the standard model. The latest LHCb measurements of R_K* offer some new insight beyond the…

High Energy Physics - Phenomenology · Physics 2017-11-29 T. Hurth , F. Mahmoudi , D. Martinez Santos , S. Neshatpour

Considering the recent experimental results on exclusive semileptonic $B$ meson decays showing sizable departure from their Standard Model prediction of lepton flavor universality and keeping ongoing and proposed non-standard Higgs searches…

High Energy Physics - Phenomenology · Physics 2019-07-25 Aritra Biswas , Dilip Kumar Ghosh , Sunando Kumar Patra , Avirup Shaw

Recently, the LHCb collaboration announced a preliminary result of the test of lepton flavor universality (LFU) in $B\to D^{(\ast)}$ semi-leptonic decays: $R_{D}^{\rm LHCb2022} = 0.441 \pm 0.089$ and $R_{D^{\ast}}^{\rm LHCb2022} = 0.281 \pm…

High Energy Physics - Phenomenology · Physics 2024-05-30 Syuhei Iguro , Teppei Kitahara , Ryoutaro Watanabe
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