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Excited-state contamination is one of the dominant uncertainties in lattice calculations of the nucleon axial-charge, $g_A$. Recently published results in leading-order chiral perturbation theory (ChPT) predict the excited-state…

High Energy Physics - Lattice · Physics 2018-03-14 Maxwell T. Hansen , Harvey B. Meyer

The nucleon axial charge is calculated as a function of the pion mass in full QCD. Using domain wall valence quarks and improved staggered sea quarks, we present the first calculation with pion masses as light as 354 MeV and volumes as…

Neutrinoless double beta decay, if detected, would prove that neutrinos are Majorana fermions and provide the direct evidence for lepton number violation. If such decay would exist in nature, then $\pi^-\pi^-\to ee$ and $\pi^-\to\pi^+ ee$…

High Energy Physics - Lattice · Physics 2019-12-04 Xin-Yu Tuo , Xu Feng , Lu-Chang Jin

The finite size effects on nucleon masses are calculated in relativistic chiral perturbation theory. Results are compared with two-flavor lattice results.

High Energy Physics - Lattice · Physics 2017-08-23 A. Ali Khan , T. Bakeyev , M. Göckeler , T. R. Hemmert , R. Horsley , A. C. Irving , D. Pleiter , P. E. L. Rakow , G. Schierholz , H. Stüben

An overview of Chiral Perturbation Theory calculations in the mesonic sector at the two Loop level is given. Discussed in some detail are the partially quenched case relevant for lattice QCD, the general fitting procedures and $\pi\pi$,$\pi…

High Energy Physics - Phenomenology · Physics 2009-11-10 Johan Bijnens

The RQCD collaboration proposed a projection method to remove the excited state contamination in lattice OCD calculations of nuclear form factors. The effectiveness of this method in removing the two-particle nucleon-pion-state…

High Energy Physics - Lattice · Physics 2020-02-28 Oliver Bar

We performed a precise calculation of physical quantities related to the axial structure of the nucleon using 2+1 flavor lattice QCD gauge configuration (PACS10 configuration) generated at the physical point with lattice volume larger than…

We calculate pion mass, pion decay constant, PCAC quark mass and nucleon mass in two flavour lattice QCD with unimproved Wilson fermion and gauge actions. Simulations are performed using DD-HMC algorithm at two lattice spacings and two…

High Energy Physics - Lattice · Physics 2015-06-12 Abhishek Chowdhury , Asit K. De , Sangita De Sarkar , A. Harindranath , Jyotirmoy Maiti , Santanu Mondal , Anwesa Sarkar

We present an exploratory lattice QCD calculation of the neutrinoless double beta decay $\pi\pi\to ee$. Under the mechanism of light-neutrino exchange, the decay amplitude involves significant long-distance contributions. The calculation…

High Energy Physics - Lattice · Physics 2019-01-23 Xu Feng , Lu-Chang Jin , Xin-Yu Tuo , Shi-Cheng Xia

I describe how simulations of lattice QCD using the path integral formulation provide the two basic quantum mechanical properties of QCD, its ground state in which correlation functions are calculated, and Fock state wavefunctions between…

High Energy Physics - Lattice · Physics 2023-01-20 Rajan Gupta

Lattice QCD simulations have made significant progress in the calculation of nucleon electromagnetic form factors in the chiral regime in recent years. With simulation results achieving pion masses of order ~180 MeV, there is an apparent…

High Energy Physics - Lattice · Physics 2013-05-30 J. M. M. Hall , D. B. Leinweber , R. D. Young

Contributions of strange quarks to the mass and spin of the nucleon, characterized by the observables f_Ts and Delta s, respectively, are investigated within lattice QCD. The calculation employs a 2+1-flavor mixed-action lattice scheme,…

High Energy Physics - Lattice · Physics 2013-05-30 M. Engelhardt

We calculate long distance contributions to $K\to\pi\nu\bar{\nu}\,,\ \pi\pi\nu\bar{\nu}$, and $\pi\pi\pi\nu\bar{\nu}$ modes within the framework of chiral perturbation theory. We find that these contributions to decay rates of $K\to…

High Energy Physics - Phenomenology · Physics 2009-10-28 C. Q. Geng , I. J. Hsu , Y. C. Lin

We report results on the nucleon structure obtained from the lattice quantum chromodynamics calculation. These include the axial, electromagnetic, $\pi NN$, and scalar form factors. The calculation is carried out at $\beta = 6$ on a $16^3…

High Energy Physics - Lattice · Physics 2009-09-25 Keh-Fei Liu

We report on recent work about the study of quark mass dependence of nucleon magnetic moments and axial-vector coupling constant. We examine the feasibility of chiral effective field theory methods for the extrapolation of lattice QCD data…

High Energy Physics - Lattice · Physics 2009-11-10 Thomas R. Hemmert , Massimiliano Procura , Wolfram Weise

Chiral perturbation theory is the effective field theory of the standard model. In this talk, I discuss some applications of this framework to the pion--nucleon system. These are chiral corrections to the S--wave pion--nucleon scattering…

High Energy Physics - Phenomenology · Physics 2011-04-15 Ulf-G. Meißner

We study pion-pion scattering in partially-quenched twisted-mass lattice QCD using chiral perturbation theory. The specific partially-quenched setup corresponds to that used in numerical lattice QCD calculations of the $I=0$ scattering…

High Energy Physics - Lattice · Physics 2022-03-02 Zachary T. Draper , Stephen R. Sharpe

Within the one-loop approximation of baryon chiral perturbation theory we calculate all one-pion and two-pion exchange contributions to the nucleon-nucleon interaction. In fact we construct the elastic NN-scattering amplitude up to and…

Nuclear Theory · Physics 2009-10-30 N. Kaiser , R. Brockmann , W. Weise

I will review heavy baryon chiral perturbation theory for the nucleon delta degrees of freedom and then examine the recent dynamical lattice calculations of the nucleon mass from the BMW, ETM, JLQCD, LHP, MILC, NPLQCD, PACS-CS, QCDSF/UKQCD…

High Energy Physics - Lattice · Physics 2009-12-04 Andre Walker-Loud

We evaluate the $\pi N$ coupling constant using a QCD sum rule based on the pion-to-vacuum matrix element of the correlator of two interpolating nucleon fields. The part of the correlator with Dirac structure $k\llap/\gamma_5$ is used,…

High Energy Physics - Phenomenology · Physics 2009-10-28 Michael C. Birse , Boris Krippa