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Within the Standard Model, the branching fraction of the rare decay $B_s\to K^0\bar K^0$ is related to other decay rates and CP asymmetries through the approximate $SU(3)$ flavor symmetry of the strong interactions and the heavy-quark…

High Energy Physics - Phenomenology · Physics 2025-06-11 Yuval Grossman , Yosef Nir , Matthias Neubert , Yogev Shpilman , Yehonatan Viernik

The R_K measurement by LHCb suggests non-standard lepton non-universality (LNU) to occur in b -> s l+ l- transitions, with effects in muons rather than electrons. A number of other measurements of b -> s l+ l- transitions by LHCb and…

High Energy Physics - Phenomenology · Physics 2016-10-17 Diego Guadagnoli , Dmitri Melikhov , Meril Reboud

The observed branching ratios for $B\to K \eta'$ decays are much larger than factorization predictions in the Standard Model (SM). Many proposals have been made to reconcile the data and theoretical predictions. In this paper we study these…

High Energy Physics - Phenomenology · Physics 2014-11-17 Han-Kuei Fu , Xiao-Gang He , Yu-Kuo Hsiao

We study the contributions of supersymmetric models with a $U(1)$ horizontal symmetry and only spontaneous CP breaking to various lepton flavor observables, such as $\mu \to e\gamma$ and the electron electric dipole moment. We show that…

High Energy Physics - Phenomenology · Physics 2021-12-16 Daniel Aloni , Pouya Asadi , Yuichiro Nakai , Matthew Reece , Motoo Suzuki

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

Motivated by recent results by the ATLAS and CMS collaborations on the angular distribution of the $B \to K^* \mu^+\mu^-$ decay, we perform a state-of-the-art analysis of rare $B$ meson decays based on the $b \to s \mu \mu$ transition.…

High Energy Physics - Phenomenology · Physics 2017-06-28 Wolfgang Altmannshofer , Christoph Niehoff , Peter Stangl , David M. Straub

The existing anomalies appearing in decays of the form $b\to s \ell^+ \ell^-$ constitute a possible hint for new physics. We point out that modifications to the SM results due to heavy neutrinos could account for the observed deviations…

High Energy Physics - Phenomenology · Physics 2017-06-30 Xiao-Gang He , German Valencia

The recent measurements of $R_{K^+}$, $R_{K_S^0}$, $R_{K^{*+}}$, $B_s\to\mu^+\mu^-$, a set of CP-averaged angular observables for the $B^0\to K^{*0}\mu^+\mu^-$ decay, and its isospin partner $B^+\to K^{*+}\mu^+\mu^-$ by the LHCb…

High Energy Physics - Phenomenology · Physics 2022-06-08 Shuang-Yi Li , Rui-Xiang Shi , Li-Sheng Geng

We study the phenomenology of simplified $Z^\prime$ models with a global $U(2)^3$ flavour symmetry in the quark sector, broken solely by the Standard Model Yukawa couplings. This flavour symmetry, known as less-minimal flavour violation,…

High Energy Physics - Phenomenology · Physics 2020-05-13 Lorenzo Calibbi , Andreas Crivellin , Fiona Kirk , Claudio Andrea Manzari , Leonardo Vernazza

We review the present status of CP violating problem in supersymmetric extensions of the standard model. We analyze the constraints imposed by the experimental limits of the electron, neutron, and mercury electric dipole moments on the…

High Energy Physics - Phenomenology · Physics 2014-11-17 Shaaban Khalil

We review the recent highlights of theoretical flavour physics, based on the theory summary talk given at FPCP2017. Over the past years, a number of intriguing anomalies have emerged in flavour violating $K$ and $B$ meson decays,…

High Energy Physics - Phenomenology · Physics 2017-08-31 Monika Blanke

Recently, several new experimental results of the test of lepton flavor universality (LFU) in $B\to D^{(\ast)}$ semi-leptonic decays were announced: the first result of $R_{D}$ from the LHCb Run 1 data, the first results of $R_{D}$ and…

High Energy Physics - Phenomenology · Physics 2024-10-11 Syuhei Iguro , Teppei Kitahara , Ryoutaro Watanabe

The discrepancies between $b\to s\ell^+\ell^-$ data and the corresponding Standard Model predictions point to the existence of new physics with a significance at the $5\sigma$ level. While previously a lepton flavour universality violating…

High Energy Physics - Phenomenology · Physics 2023-12-06 Andreas Crivellin , Matthew Kirk

We present a measurement of angular observables and a test of lepton flavor universality in the $B\to K^\ast \ell^+\ell^-$ decay, where $\ell$ is either $e$ or $\mu$. The analysis is performed on a data sample corresponding to an integrated…

High Energy Physics - Experiment · Physics 2016-12-16 Belle Collaboration , S. Wehle , C. Niebuhr , S. Yashchenko , I. Adachi , H. Aihara , S. Al Said , D. M. Asner , V. Aulchenko , T. Aushev , R. Ayad , T. Aziz , V. Babu , A. M. Bakich , V. Bansal , E. Barberio , W. Bartel , P. Behera , B. Bhuyan , J. Biswal , A. Bobrov , A. Bondar , G. Bonvicini , A. Bozek , M. Bračko , T. E. Browder , D. Červenkov , P. Chang , V. Chekelian , A. Chen , B. G. Cheon , K. Chilikin , R. Chistov , K. Cho , Y. Choi , D. Cinabro , N. Dash , J. Dingfelder , Z. Drásal , D. Dutta , S. Eidelman , D. Epifanov , H. Farhat , J. E. Fast , T. Ferber , B. G. Fulsom , V. Gaur , N. Gabyshev , A. Garmash , R. Gillard , P. Goldenzweig , B. Golob , O. Grzymkowska , E. Guido , J. Haba , T. Hara , K. Hayasaka , H. Hayashii , M. T. Hedges , W. -S. Hou , C. -L. Hsu , T. Iijima , K. Inami , G. Inguglia , A. Ishikawa , R. Itoh , Y. Iwasaki , W. W. Jacobs , I. Jaegle , H. B. Jeon , Y. Jin , D. Joffe , K. K. Joo , T. Julius , A. B. Kaliyar , K. H. Kang , G. Karyan , P. Katrenko , T. Kawasaki , H. Kichimi , C. Kiesling , D. Y. Kim , H. J. Kim , J. B. Kim , K. T. Kim , M. J. Kim , S. H. Kim , K. Kinoshita , L. Koch , P. Kodyš , S. Korpar , D. Kotchetkov , P. Križan , P. Krokovny , T. Kuhr , R. Kulasiri , T. Kumita , A. Kuzmin , Y. -J. Kwon , J. S. Lange , C. H. Li , L. Li , Y. Li , L. Li Gioi , J. Libby , M. Lubej , T. Luo , M. Masuda , T. Matsuda , K. Miyabayashi , H. Miyake , R. Mizuk , G. B. Mohanty , T. Mori , R. Mussa , E. Nakano , M. Nakao , T. Nanut , K. J. Nath , Z. Natkaniec , M. Nayak , N. K. Nisar , S. Nishida , S. Ogawa , H. Ono , Y. Onuki , G. Pakhlova , B. Pal , C. -S. Park , C. W. Park , H. Park , S. Paul , L. Pesántez , L. E. Piilonen , C. Pulvermacher , J. Rauch , M. Ritter , A. Rostomyan , Y. Sakai , S. Sandilya , L. Santelj , T. Sanuki , Y. Sato , V. Savinov , T. Schlüter , O. Schneider , G. Schnell , C. Schwanda , A. J. Schwartz , Y. Seino , K. Senyo , O. Seon , I. S. Seong , M. E. Sevior , C. P. Shen , T. -A. Shibata , J. -G. Shiu , B. Shwartz , F. Simon , R. Sinha , E. Solovieva , M. Starič , J. F. Strube , K. Sumisawa , T. Sumiyoshi , M. Takizawa , U. Tamponi , F. Tenchini , T. Tsuboyama , M. Uchida , T. Uglov , Y. Unno , S. Uno , P. Urquijo , Y. Ushiroda , Y. Usov , S. E. Vahsen , C. Van Hulse , G. Varner , K. E. Varvell , V. Vorobyev , A. Vossen , E. Waheed , C. H. Wang , M. -Z. Wang , P. Wang , M. Watanabe , Y. Watanabe , E. Widmann , K. M. Williams , E. Won , H. Yamamoto , Y. Yamashita , H. Ye , Y. Yook , C. Z. Yuan , Y. Yusa , Z. P. Zhang , V. Zhilich , V. Zhukova , V. Zhulanov , M. Ziegler , A. Zupanc

Lepton-flavour violating tau-decays are predicted in many extensions of the Standard Model at a rate observable at future collider experiments. In this article we focus on the decay tau to mu mu antimu, which is a promising channel to…

High Energy Physics - Phenomenology · Physics 2008-11-26 M. Giffels , J. Kallarackal , M. Kramer , B. O'Leary , A. Stahl

The LHCb has measured the ratios of $B\to K^\ast\mu^+\mu^-$ to $B\to K^\ast e^+ e^-$ branching fractions in two dilepton invariant mass squared bins, which deviate from the Standard Model predictions by approximately $2.5\sigma$. These new…

High Energy Physics - Phenomenology · Physics 2017-12-07 Diganta Das , Chandan Hati , Girish Kumar , Namit Mahajan

In view of both the latest LHCb measurement of $R_{K^{(*)}}$ and the new $2.8\sigma$ deviation reported by Belle II on $B^{+}\to K^{+}\nu\bar{\nu}$ decays, we present a fit to the $B$ meson anomalies for various one and two dimensional…

High Energy Physics - Phenomenology · Physics 2024-02-19 Peter Athron , R. Martinez , Cristian Sierra

Very recent experimental information obtained from the Belle experiment, along with that accumulated by the BABAR and LHCb experiments, has shown the existence of anomalies in the ratios $R(D)$ and $R(D^{*})$ associated with the…

High Energy Physics - Phenomenology · Physics 2019-11-22 John D. Gomez , Néstor Quintero , Eduardo Rojas

We analyse the violations of lepton-flavour universality in the ratios B(P -> l nu)/B(P -> l' nu) using a general effective theory approach, discussing various flavour-symmetry breaking patterns of physics beyond the SM. We find that in…

High Energy Physics - Phenomenology · Physics 2009-11-05 Alberto Filipuzzi , Gino Isidori

A search for the lepton flavour violating decays $\tau^- \to l^- K^0_{\scriptscriptstyle S}$ ($l = e$ or $\mu$) has been performed using a data sample corresponding to an integrated luminosity of 469 ${fb}^{-1}$, collected with the…

High Energy Physics - Experiment · Physics 2010-04-12 The BaBar Collaboration , B. Aubert