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The HyperCP experiment reported the observation of three events for the $\Sigma^+ \rightarrow p \mu^+\mu^-$ decay. The dimuon masses of the observed events are clustered within the detector resolution of 1 MeV/$c^2$. These decays might be…

High Energy Physics - Experiment · Physics 2010-06-14 HyoJung Hyun

We present an analysis of the rare exclusive $B$ decays $B\to K\nu\bar\nu$ and $B\to K^{*}\nu\bar\nu$ within the Standard Model (SM), in a model-independent manner, and in a number of new physics (NP) models. Combining new form factor…

High Energy Physics - Phenomenology · Physics 2014-12-17 Andrzej J. Buras , Jennifer Girrbach-Noe , Christoph Niehoff , David M. Straub

With updated experimental data and improved theoretical calculations, several significant deviations are being observed between the Standard Model predictions and the experimental measurements of the branching ratios of $\bar{B}_{(s)}^0\to…

High Energy Physics - Phenomenology · Physics 2021-11-17 Fang-Min Cai , Wei-Jun Deng , Xin-Qiang Li , Ya-Dong Yang

The localized excess of $B\rightarrow K + \textit{invisible}$ events reported by Belle-II is commonly interpreted as a signal for $B\to Ka$, where $a$ is an axion-like particle (ALP). In these proceedings, we summarize two theoretical…

High Energy Physics - Phenomenology · Physics 2025-12-01 Xiyuan Gao

We present a detailed discussion of the current theoretical and experimental situation of the anomaly in the angular distribution of $B \to K^*(\to K\pi)\mu^+\mu^-$, observed at LHCb in the $1~\text{fb}^{-1}$ dataset and recently confirmed…

High Energy Physics - Phenomenology · Physics 2016-07-20 Sébastien Descotes-Genon , Lars Hofer , Joaquim Matias , Javier Virto

We study lepton polarization asymmetries in the (Lambda_b -> Lambda l^+ l^-) decay using the most general model independent effective Hamiltonian. The dependence of the lepton polarizations and their combinations on the new Wilson…

High Energy Physics - Phenomenology · Physics 2011-03-23 T. M. Aliev , A. Ozpineci , M. Savci

The rare decay B --> K* mu+ mu- is considered to be a golden channel for LHCb, as the polarization of the K* allows a precise angular reconstruction resulting in many observables that offer new important tests of the Standard Model and its…

High Energy Physics - Phenomenology · Physics 2009-05-11 Aoife Bharucha

Recently, the Belle II collaboration announced the first measurement of $\mathcal B(B^+\to K^+\nu\bar\nu)$, which is found to be about $2.7\sigma$ higher than the SM prediction. We decipher the data with two new physics scenarios: the…

High Energy Physics - Phenomenology · Physics 2024-03-15 Biao-Feng Hou , Xin-Qiang Li , Meng Shen , Ya-Dong Yang , Xing-Bo Yuan

The increasing number of flavour anomalies motivates the investigation of new processes where tensions similar to the observed ones may emerge. It is necessary to identify observables sensitive to physics beyond the Standard Model. The…

High Energy Physics - Phenomenology · Physics 2022-09-20 Francesco Loparco

We analyze the $5\sigma$ difference between the CP asymmetries of the $B^0 \to K^+ \pi^-$ and $B^+ \to K^+ \pi^0$ decays within the Soft Collinear Effective Theory. We find that in the Standard Model, such a big difference cannot be…

High Energy Physics - Phenomenology · Physics 2010-05-25 K. Huitu , S. Khalil

The rare decay $B^0_s \to \mu^+\mu^-$ plays a key role for the testing of the Standard Model. It is pointed out that the sizable decay width difference $\Delta\Gamma_s$ of the $B_s$-meson system affects this channel in a subtle way. As a…

High Energy Physics - Phenomenology · Physics 2014-08-26 Robert Fleischer

The recent measurements on $R_D$, $R_{D^*}$ and $R_{J/\psi}$ by three pioneering experiments, BaBar, Belle and LHCb, indicate that the notion of lepton flavour universality is violated in the weak charged-current processes, mediated through…

High Energy Physics - Phenomenology · Physics 2021-08-06 Aishwarya Bhatta , Atasi Ray , Rukmani Mohanta

Indirect signs of new physics beyond the Standard Model may be appearing in $B \to K^{(*)}\mu^+\mu^-$ decays. If confirmed, the title question will be of paramount importance in determining the strategy for future colliders. We answer it by…

High Energy Physics - Phenomenology · Physics 2018-05-14 Tevong You

Using the most general model independent form of the effective Hamiltonian, the rare B_s --> \gamma \ell^+ \ell^- decays are studied by taking into account the polarization of the photon. The total and the differential branching ratios for…

High Energy Physics - Phenomenology · Physics 2011-09-13 U. O. Yilmaz , B. B. Sirvanli , G. Turan

We revisit the decay $\Lambda_b^0\to \Lambda_c^+ \ell^-\bar\nu$ ($\ell = e,\mu,\tau$) with a subsequent two-body decay $\Lambda_c^+ \to \Lambda^0 \pi^+$ in the Standard Model and in generic New Physics models. The decay's joint…

High Energy Physics - Phenomenology · Physics 2022-08-01 Philipp Böer , Ahmet Kokulu , Jan-Niklas Toelstede , Danny van Dyk

Color-suppressed decays of $B$ mesons to final states with $\psi(2S)$ mesons have been observed with the CLEO detector. The branching fractions for the decays $B^+ \to \psi(2S) K^+$, $B^+ \to \psi(2S) K^*(892)^+$, $B^0 \to \psi(2S) K^0$,…

High Energy Physics - Experiment · Physics 2010-04-08 S. Richichi , CLEO Collaboration

The confirmation of excess in $R_{D^*}$ at the LHCb is an indication of lepton flavor non-universality. Various different new physics operators and their coupling strengths, which provide a good fit to $R_D$, $R_{D^*}$ and $q^2$ spectra,…

High Energy Physics - Phenomenology · Physics 2017-07-31 Ashutosh Kumar Alok , Dinesh Kumar , Suman Kumbhakar , S Uma Sankar

The rare decay B -> K* (-> K pi) mu+ mu- is regarded as one of the crucial channels for B physics as the polarization of the K* allows a precise angular reconstruction resulting in many observables that offer new important tests of the…

High Energy Physics - Phenomenology · Physics 2011-05-23 Wolfgang Altmannshofer , Patricia Ball , Aoife Bharucha , Andrzej J. Buras , David M. Straub , Michael Wick

In this talk I give an introduction to methods used to give a model independent description of QCD effects in B-decays. I discuss three useful expansions: mb/mW << 1 for the electroweak Hamiltonian, LambdaQCD/mb << 1 for Heavy Quark…

High Energy Physics - Phenomenology · Physics 2007-05-23 Iain W. Stewart

We examine the new physics sensitivity of the rare decay $\Lambda_b \to \Lambda \nu\bar\nu$ which can be accessible at future $Z$-pole machines like FCC-ee and CEPC. We find that the longitudinal polarization of $\Lambda_b$ baryons produced…

High Energy Physics - Phenomenology · Physics 2025-03-11 Wolfgang Altmannshofer , Sri Aditya Gadam , Kevin Toner