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In order to determine the ratio of CKM matrix elements |V_{ub}/V_{cb}| (and |V_{ub}|), we propose a new model-independent method based on the heavy quark effective theory, which is theoretically described by the phase space factor and the…

High Energy Physics - Phenomenology · Physics 2014-11-17 C. S. Kim

The Wolfenstein parametrization of the $3\times 3$ Kobayashi-Maskawa (KM) matrix $V$ is modified by keeping its unitarity up to the accuracy of $O(\lambda^{6})$. This modification can self-consistently lead to the off-diagonal asymmetry of…

High Energy Physics - Phenomenology · Physics 2010-11-01 Zhi-zhong Xing

A search for direct CP violation in the non-leptonic decays of hyperons has been performed. In comparing the product of the decay parameters, $\alpha_{\Xi}\alpha_{\Lambda}$, in terms of an asymmetry parameter, $A_{\Xi\Lambda}$, between…

High Energy Physics - Experiment · Physics 2008-11-26 K. B. Luk , H. T. Diehl , J. Duryea , G. Guglielmo , K. Heller , P. M. Ho , C. James , K. Johns , M. J. Longo , R. Rameika , S. Teige , G. B. Thomson

We calculate the leading-order matrix element for the decay $B \to K^* \gamma$ in the quenched approximation of lattice QCD on a $24^3 \times 48$ lattice at $\beta=6.2$, using an O(a)-improved fermion action. Extrapolating the quark masses…

High Energy Physics - Lattice · Physics 2015-06-25 UKQCD Collaboration

We present the first complete lattice QCD calculation of the four structure-dependent form factors governing the rare charged kaon decay $K^- \to \ell^- \bar{\nu}_\ell \ell'^+ \ell'^-$, with fully controlled statistical and systematic…

High Energy Physics - Lattice · Physics 2026-05-22 R. Di Palma , R. Frezzotti , G. Gagliardi , V. Lubicz , G. Martinelli , C. T. Sachrajda , F. Sanfilippo , S. Simula , N. Tantalo

We present an efficient method for extracting energy levels from lattice QCD correlation functions by computing the eigenvalues of the transfer matrix associated with the lattice QCD Hamiltonian. While mathematically and numerically…

High Energy Physics - Lattice · Physics 2025-06-25 Debsubhra Chakraborty , Dhruv Sood , Archana Radhakrishnan , Nilmani Mathur

The electromagnetic coupling constant, $\alpha$, is one of the fundamental parameters of the Standard Model (SM). Its value at the Z boson mass, $\alpha(M_Z)$, is of particular interest as it enters electroweak precision tests. When running…

High Energy Physics - Lattice · Physics 2024-01-09 Sophie Mutzel

The quantity $\varepsilon'/\varepsilon$ measures direct CP violation in Kaon decays. Recent SM predictions show a $2.9\sigma$ tension with data, with the theoretical uncertainty dominating. As rapid progress on the lattice is bringing…

High Energy Physics - Phenomenology · Physics 2017-04-05 M Cerdà-Sevilla , M Gorbahn , S Jäger , A Kokulu

We investigate CP violation in the decay process $\bar B_{s} \rightarrow V V \rightarrow K^{+}K^{-}K^{+}K^{-}$ within the framework of perturbative QCD, where V represents vector mesons $\phi$, $\rho$, and $\omega$. We analyze the mixing…

High Energy Physics - Phenomenology · Physics 2025-01-14 Chang-Chang Zhang , Gang Lü

We present preliminary results for the calculation of the Kaon Bag parameter $B_K$ in $N_f=2+1$ lattice QCD, using M\"obius Domain Wall Fermion ensembles generated by the RBC-UKQCD collaboration. This computation is done directly at…

High Energy Physics - Lattice · Physics 2013-12-10 Julien Frison , Peter Boyle , Norman H. Christ , Nicolas Garron , Robert Mawhinney , Chris T. Sachrajda , Hantao Yin

Weak decays of charged kaons with an additional lepton-antilepton pair, $K^- \to \ell^- \bar{\nu}_\ell \ell'^{+} \ell'^{-}$ ($K_{\ell2\ell'}$), are suppressed at order $O(G_{F}^{2}\alpha_{\rm em}^{2})$ in the Standard Model (SM) and provide…

High Energy Physics - Phenomenology · Physics 2026-05-22 R. Di Palma , R. Frezzotti , G. Gagliardi , V. Lubicz , G. Martinelli , C. T. Sachrajda , F. Sanfilippo , S. Simula , N. Tantalo

We study local CP-violation on the lattice by measuring the local correlation between the topological charge density and the electric dipole moment of quarks, induced by a constant external magnetic field. This correlator is found to…

High Energy Physics - Lattice · Physics 2015-06-18 G. S. Bali , F. Bruckmann , G. Endrodi , Z. Fodor , S. D. Katz , A. Schafer

We develop a methodology for the computation of the $K\to \ell\nu_\ell \ell'^+ \ell'^-$ decay width using lattice QCD and present an exploratory study here. We use a scalar function method to account for the momentum dependence of the decay…

High Energy Physics - Lattice · Physics 2022-04-06 Xin-Yu Tuo , Xu Feng , Lu-Chang Jin , Teng Wang

We obtain a new value for the QCD coupling constant by combining lattice QCD simulations with experimental data for hadron masses. Our lattice analysis is the first to: 1) include vacuum polarization effects from all three light-quark…

High Energy Physics - Lattice · Physics 2009-11-11 Q. Mason , H. D. Trottier , C. T. H. Davies , K. Foley , A. Gray , G. P. Lepage , M. Nobes , J. Shigemitsu

We discuss the extraction of the ground state $\langle \mathrm{K} ({\bf p})|V_\mu(0)|\mathrm{B} ({\bf 0})\rangle$ matrix elements from Euclidean lattice correlation functions. The emphasis is on the elimination of excited state…

High Energy Physics - Lattice · Physics 2019-10-23 Felix Bahr , Debasish Banerjee , Fabio Bernardoni , Mateusz Koren , Hubert Simma , Rainer Sommer

We establish a general upper bound for $K$-fold cross-validation ($K$-CV) errors that can be adapted to many $K$-CV-based estimators and learning algorithms. Based on Rademacher complexity of the model and the Orlicz-$\Psi_{\nu}$ norm of…

Machine Learning · Statistics 2020-07-31 Ning Xu , Timothy C. G. Fisher , Jian Hong

We investigate the exclusive rare baryonic $\Lambda_{b}\to\Lambda\ell^{+}\ell^{-}$ in a family non-universal $Z^{\prime}$ model, which is one of the natural extension of standard model. Using transition form factors, calculated in the…

High Energy Physics - Phenomenology · Physics 2015-03-18 M. Ali Paracha , Ishtiaq Ahmed , M. Jamil Aslam

We discuss the interplay between two first-principles calculations of QCD at high density: perturbative results in the weak-coupling regime and the recent lattice-QCD result at finite isospin density. By comparing these two results, we…

High Energy Physics - Phenomenology · Physics 2024-09-09 Yuki Fujimoto

We present the first QCD-based calculation of hadronic matrix elements with penguin topology determining direct CP-violating asymmetries in $D^0\to \pi^-\pi^+$ and $D^0\to K^- K^+$ nonleptonic decays. The method is based on the QCD…

High Energy Physics - Phenomenology · Physics 2017-10-11 Alexander Khodjamirian , Alexey A. Petrov

Heavy meson HQET light-cone distribution amplitudes (LCDAs) are critical for precision predictions of $B$ meson weak decays, but currently are one of dominant theoretical uncertainties that obscure interpretations of $B$ anomalies and…