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We determine chiral loop corrections to the B meson decay amplitudes to positive and negative parity charmed mesons within a framework which combines heavy quark and chiral symmetries. We find that corrections due to states of opposite…

High Energy Physics - Phenomenology · Physics 2008-10-14 Jan O. Eeg , Svjetlana Fajfer , Jernej F. Kamenik

We study the impact of LEP2 constraints on the dimensionless coefficients of the electroweak chiral Lagrangian on the precision observables using the improved renormalization group equations. We find that the current uncertainty in the…

High Energy Physics - Phenomenology · Physics 2007-05-23 Sukanta Dutta , Kaoru Hagiwara , Qi-Shu Yan

We present a calculation of the B -> pi l nu form factors with domain-wall light quarks and relativistic b-quarks on the lattice. We work with the 2+1 flavor domain-wall fermion and Iwasaki gauge-field ensembles generated by the RBC and…

High Energy Physics - Lattice · Physics 2013-11-06 Taichi Kawanai , Ruth S. Van de Water , Oliver Witzel

It has been argued recently that the inclusion of the chiral logarithms in extrapolation of the lattice data can shift the value of the hadronic parameter xi = (fBs sqrt(B_{Bs}))/(fBd sqrt(B_{Bd})), from 1.16(6) to 1.32(10) and even higher.…

High Energy Physics - Phenomenology · Physics 2009-11-07 Damir Becirevic , Svjetlana Fajfer , Sasa Prelovsek , Jure Zupan

We calculate the leptonic decay constants of B_{(s)} and D_{(s)} mesons in lattice QCD using staggered light quarks and Fermilab bottom and charm quarks. We compute the heavy-light meson correlation functions on the MILC asqtad-improved…

We propose to construct a chirally broken model based on the infrared fixed point of a conformal system by raising the mass of some flavors while keeping the others massless. In the infrared limit the massive fermions decouple and the…

High Energy Physics - Phenomenology · Physics 2016-04-29 R. C. Brower , A. Hasenfratz , C. Rebbi , E. Weinberg , O. Witzel

We present the computation of the leading one-loop electroweak radiative corrections to the non-standard top quark decay width Gamma(t->H+ b), using a physically motivated definition of tan(beta). We find that the corrections are large,…

High Energy Physics - Phenomenology · Physics 2007-05-23 J. A. Coarasa , Jaume Guasch , Joan Sola

This talk concerns some theoretical patterns of the helicity amplitudes for t --> W b decay. The patterns involve both the standard model's four decay helicity amplitudes, A_{SM}, and also the amplitudes A_{+} in the case of an additional…

High Energy Physics - Phenomenology · Physics 2007-05-23 Charles A. Nelson

The decay modes of the type $B \to \pi \, D $ are dynamically different. For the case $\bar{B_{d}^0} \to \pi^- D^{+} $ there is a substantial factorized contribution which dominates. In contrast, the decay mode $\bar{B_{d}^0} \to \pi^0…

High Energy Physics - Phenomenology · Physics 2014-11-20 Lars E. Leganger , Jan O. Eeg

We describe two recent theoretical calculations of the $B \to K^* \gamma$ decay. The first method is based on an effective lagrangian incorporating chiral symmetry for the light degrees of freedom and the heavy quark spin-flavor symmetries…

High Energy Physics - Phenomenology · Physics 2007-05-23 G. Nardulli

We report on our re-calculation of electroweak top-quark pair production in Standard Model extensions with extra heavy neutral and charged spin-1 particles at the LHC with substantial improvements. In particular, we allow for…

High Energy Physics - Phenomenology · Physics 2021-01-21 M. M. Altakach , T. Ježo , M. Klasen , J. -N. Lang , I. Schienbein

An interesting extension of the Standard Model is based on the electroweak gauge group SU(3)_L x U(1). It requires three generations to cancel anomalies, treats the third generation differently than the first two, and has a rich…

High Energy Physics - Phenomenology · Physics 2008-11-26 J. -Alexis Rodriguez , Marc Sher

We perform a systematic one-loop renormalization on the electroweak chiral Lagrangian (EWCL) up to $O(p^4)$ operators and construct the renormalization group equations (RGE) for the anomalous couplings. We examine the impact of the triple…

High Energy Physics - Phenomenology · Physics 2009-11-11 Qi-Shu Yan

We update the indirect bounds on anomalous triple gauge couplings coming from the non-universal one-loop contributions to the $Z \to b \bar{b}$ width. These bounds, which are independent of the Higgs boson mass, are in agreement with the…

High Energy Physics - Phenomenology · Physics 2008-11-26 O. J. P. Eboli , M. C. Gonzalez-Garcia , S. F. Novaes

We present recent results of the rare semileptonic decay B -> X_s l+ l-. We particularly focus on higher order electroweak corrections in the Standard Model (SM) as well as O(alpha_s) corrections in Two-Higgs-doublet models (THDM), both of…

High Energy Physics - Phenomenology · Physics 2016-09-06 T. Huber , S. Schilling

We calculate the B-meson decay constants f_B, f_Bs, and their ratio in unquenched lattice QCD using domain-wall light quarks and relativistic b-quarks. We use gauge-field ensembles generated by the RBC and UKQCD collaborations using the…

We determine the chiral corrections to the matrix elements of the Delta B=0 four-quark operators which are relevant to the studies of the ratios of lifetimes of heavy-light mesons as well as to the power corrections to the inclusive…

High Energy Physics - Phenomenology · Physics 2009-01-16 Damir Becirevic , Svjetlana Fajfer , Jernej F. Kamenik

We formulate the electroweak chiral Lagrangian in its mass eigenstates, and study the its one-loop renormalization and provide its renormalization group equations to the same order, so as to complete it as the low energy effective theory of…

High Energy Physics - Phenomenology · Physics 2007-05-23 Q. S. Yan , D. S. Du

We examine the three-body baryonic $\bar B\to {\bf B\bar B'}V$ decays with $V$ vector mesons in the standard model. We can simultaneously explain the recent experimental data on the decays of $B^-\to \Lambda\bar p \,\rho^0$ and $\bar B\to…

High Energy Physics - Phenomenology · Physics 2013-05-30 C. Q. Geng , Y. K. Hsiao

In this talk, using deconstruction, we analyze the form of the corrections to the electroweak interactions in a large class of ``Higgsless'' models of electroweak symmetry breaking, allowing for arbitrary 5-D geometry, position-dependent…

High Energy Physics - Phenomenology · Physics 2007-05-23 Masafumi Kurachi , R. Sekhar Chivukula , Elizabeth H. Simmons , Hong-Jian He , Masaharu Tanabashi