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The QED hadronic vacuum polarization function plays an important role in the determination of precision electroweak observables and of the anomalous magnetic moment of the muon. These contributions have been computed from data, by means of…

High Energy Physics - Phenomenology · Physics 2023-11-14 Nina M. Coyle , Carlos E. M. Wagner

We study matrix elements of the "chromomagnetic" operator on the lattice. This operator is contained in the strangeness-changing effective Hamiltonian which describes electroweak effects in the Standard Model and beyond. Having dimension 5,…

High Energy Physics - Lattice · Physics 2014-10-06 M. Constantinou , M. Costa , R. Frezzotti , V. Lubicz , G. Martinelli , D. Meloni , H. Panagopoulos , S. Simula

We investigate a class of models for new physics which could produce a large difference in sin 2 beta between B0-> J/\psi K(S) and the ``pure penguin'' mode B0-> phi K(S). In such models, the dominant effect is through a Z-penguin and…

High Energy Physics - Phenomenology · Physics 2007-05-23 David Atwood , Gudrun Hiller

The leading-order electromagnetic and strong isospin-breaking corrections to the ratio of $K_{\mu 2}$ and $\pi_{\mu 2}$ decay rates are evaluated for the first time on the lattice, following a method recently proposed. The lattice results…

High Energy Physics - Lattice · Physics 2018-02-21 D. Giusti , V. Lubicz , G. Martinelli , C. T. Sachrajda , F. Sanfilippo , S. Simula , N. Tantalo , C. Tarantino

We perform a study of matrix elements relevant for the Delta I=1/2 rule and the direct CP-violation parameter epsilon-prime from first principles by computer simulation in Lattice QCD. We use staggered (Kogut-Susskind) fermions, and employ…

High Energy Physics - Lattice · Physics 2008-11-26 D. Pekurovsky , G. Kilcup

We make an attempt to clarify the role of the annihilation or "penguin" mode in the description of the $K\rightarrow\pi\pi$ decay within the Standard Model. The attention is concentrated on new operators in the effective $\Delta S=1$…

High Energy Physics - Phenomenology · Physics 2015-06-25 A. A. Penin , A. A. Pivovarov

Lattice QCD should allow a derivation of the $\Delta I=1/2$ rule from first principles, but numerical calculations to date have been plagued by a variety of problems. After a brief review of these problems, we present several new methods…

High Energy Physics - Lattice · Physics 2009-10-09 C. Dawson , G. Martinelli , G. C. Rossi , C. T. Sachrajda , S. Sharpe , M. Talevi , M. Testa

We discuss G-parity lattice boundary conditions as a means to impose momentum on the pion ground state without breaking isospin symmetry. This technique is expected to be critical for the precision measurement of…

High Energy Physics - Lattice · Physics 2020-01-29 Norman Christ , Christopher Kelly , Daiqian Zhang

The anomalous magnetic moment of muon, $g-2$, is a very precisely measured quantity. However, the current measurement disagrees with standard model by about 3 standard deviations. Hadronic vacuum polarization and hadronic light by light are…

High Energy Physics - Lattice · Physics 2015-09-29 Luchang Jin , Thomas Blum , Norman Christ , Masashi Hayakawa , Taku Izubuchi , Christoph Lehner

We present results for the leading hadronic contribution to the muon anomalous magnetic moment due to strange quark-connected vacuum polarisation effects. Simulations were performed using RBC--UKQCD's $N_f=2+1$ domain wall fermion ensembles…

We analyse in detail the role of additional hadron-hadron interactions in elastic photon-initiated (PI) production at the LHC, both in $pp$ and heavy ion collisions. We first demonstrate that the source of difference between our predictions…

High Energy Physics - Phenomenology · Physics 2021-09-27 L. A. Harland-Lang , V. A. Khoze , M. G. Ryskin

We present an updated theoretical prediction of $\epse$, using the next-to-leading $\DSone$ effective hamiltonian and lattice QCD matrix elements. The CP violating phase is costrained by using both the experimental values of $\ep$ and…

High Energy Physics - Phenomenology · Physics 2009-09-25 M. Ciuchini

We describe our recent lattice study of SU(4) gauge theory with fermions in the fundamental and sextet representations. In this theory, a new type of baryon consists of quarks in both representations. The spectrum of these "chimera baryons"…

High Energy Physics - Lattice · Physics 2016-10-21 Thomas A. DeGrand , Daniel Hackett , William I. Jay , Ethan T. Neil , Yigal Shamir , Benjamin Svetitsky

We present a GUT-model-independent calculation of hadron matrix elements for all dimension-six operators associated with baryon number violating processes using lattice QCD. Our results cover all the matrix elements required to estimate the…

High Energy Physics - Phenomenology · Physics 2016-11-23 Yoshinobu Kuramashi

The persistent discrepancy of about 3.5 standard deviations between the experimental measurement and the Standard Model prediction for the muon anomalous magnetic moment, $a_\mu$, is one of the most promising hints for the possible…

High Energy Physics - Lattice · Physics 2020-05-20 H. Wittig , A. Gérardin , Marco Cè , G. von Hippel , B. Hörz , H. B. Meyer , K. Miura , D. Mohler , K. Ottnad , A. Risch , T. San José , J. Wilhelm

We report on recent advances on the computation of the matrix elements of the electroweak penguins Q_7 and Q_8 which are relevant for the Delta I=3/2 contribution to epsilon'_K in the chiral limit. The matching of scale and scheme…

High Energy Physics - Phenomenology · Physics 2015-06-25 Elvira Gamiz , Joaquim Prades , Johan Bijnens

We discuss a possibility of large electroweak(EW) penguin contribution in B-->K pi and pi pi. The recent experimental data may be still suggesting that there are some discrepancies between the data and theoretical estimations. In B --> K pi…

High Energy Physics - Phenomenology · Physics 2007-05-23 Satoshi Mishima , Tadashi Yoshikawa

Results for response functions for kaon electroproduction on the proton are presented. A tree-level hadrodynamical model is adopted and it is shown that some of the electroproduction response functions are particularly powerful with the eye…

Nuclear Theory · Physics 2009-11-10 S. Janssen , J. Ryckebusch , T. Van Cauteren

We report on an ongoing calculation of hadronic matrix elements needed to parameterize K-Kbar mixing in generic BSM scenarios, using domain wall fermions (DWF) at two lattice spacings. Recent work by the SWME collaboration shows a…

High Energy Physics - Lattice · Physics 2013-11-05 A. T. Lytle , P. A. Boyle , N. Garron , R. J. Hudspith , C. T. Sachrajda

Moments of generalised parton distributions can be related to off-forward matrix elements of local operators. We calculate a few of the leading twist matrix elements for the pion on the lattice. The simulations are performed using two…

High Energy Physics - Lattice · Physics 2008-11-26 D. Brömmel , M. Diehl , M. Göckeler , Ph. Hägler , R. Horsley , D. Pleiter , P. E. L. Rakow , A. Schäfer , G. Schierholz , J. M. Zanotti