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Usually the simulation of scattering processes in lattice QCD is carried out at unphysically high values of the quark masses. Hence, a method to extrapolate data obtained in lattice calculations to physical masses is needed to allow for…

High Energy Physics - Phenomenology · Physics 2019-02-28 Malwin Niehus , Martin Hoferichter , Bastian Kubis

We propose analytic approximations of chiral SU(3) amplitudes for the extrapolation of lattice data to the physical meson masses. The method allows the determination of NNLO low-energy constants in a controllable fashion. We test the…

High Energy Physics - Phenomenology · Physics 2011-08-05 Gerhard Ecker , Pere Masjuan , Helmut Neufeld

We analyze lattice data for octet baryon masses from the QCDSF collaboration employing manifestly covariant Baryon Chiral Perturbation Theory. It is shown that certain combinations of low-energy constants can be fixed more accurately than…

High Energy Physics - Phenomenology · Physics 2013-03-27 P. C. Bruns , L. Greil , A. Schäfer

Using the pole shifting procedure of the modified quenched approximation (MQA) to cure the exceptional configuration problem, accurate hadron hadron spectrum calculations can be obtained at very light quark mass. Here we use the MQA to…

High Energy Physics - Lattice · Physics 2009-10-31 W. Bardeen , A. Duncan , E. Eichten , H. B. Thacker

Recent $N_f=2+1$ lattice data for meson-meson scattering in $p$-wave and isospin $I=1$ are analyzed using a unitarized model inspired by Chiral Perturbation Theory in the inverse-amplitude formulation for two and three flavors. Chiral…

High Energy Physics - Lattice · Physics 2017-08-30 B. Hu , R. Molina , M. Döring , M. Mai , A. Alexandru

We use chiral perturbation theory to study the extraction of pion electromagnetic polarizabilities from lattice QCD. Chiral extrapolation formulae are derived for partially quenched QCD, and quenched QCD simulations. On a torus, volume…

High Energy Physics - Lattice · Physics 2008-11-26 Jie Hu , Fu-Jiun Jiang , Brian C. Tiburzi

These lectures describe the use of effective field theories to extrapolate results from the parameter region where numerical simulations of lattice QCD are possible to the physical parameters (physical quark masses, infinite volume,…

High Energy Physics - Lattice · Physics 2007-05-23 Stephen. R. Sharpe

Chiral extrapolation of the $X(3872)$ binding energy is investigated using the modified Weinberg formulation of chiral effective field theory for the $D \bar{D}^*$ scattering. Given its explicit renormalisability, this approach is…

High Energy Physics - Phenomenology · Physics 2015-12-16 V. Baru , E. Epelbaum , A. A. Filin , J. Gegelia , A. V. Nefediev

In lattice QCD it is possible, in principle, to determine the parameters in the effective chiral lagrangian (including weak interaction couplings) by performing numerical simulations in the $\epsilon$--regime, i.e. at quark masses where the…

High Energy Physics - Lattice · Physics 2011-07-19 L. Giusti , C. Hoelbling , M. Lüscher , H. Wittig

We perform an analysis of QCD lattice data on masses of charmed meson with J^P = 0^- and J^P =1^- quantum numbers. The quark-mass dependence of the data set is used to gain information on the size of counter terms in the chiral Lagrangian…

High Energy Physics - Lattice · Physics 2019-04-16 Xiao-Yu Guo , Yonggoo Heo , Matthias F. M. Lutz

We extend the usual chiral perturbation theory framework ($\chi$PT) to allow the inclusion of a light dynamical isosinglet scalar. Using lattice QCD results, and a few phenomenological inputs, we explore the parameter space of the effective…

High Energy Physics - Phenomenology · Physics 2015-05-30 J. Soto , P. Talavera , J. Tarrús

Several conceptual points concerning the inclusion of the $\Delta$(1232) resonance in the framework of chiral effective-field theory are discussed, with an emphasis on the problem of power counting in the baryon sector in general. I also…

Nuclear Theory · Physics 2014-11-20 Vladimir Pascalutsa

I describe recent developments in quenched chiral perturbation theory (QChPT) and the status of weak matrix elements involving light quarks. I illustrate how, with improved statistical errors, and with calculations of the masses of baryons…

High Energy Physics - Lattice · Physics 2009-10-28 Stephen R. Sharpe

We consider chiral loop corrections to the effective couplings which describe the strong interactions of two heavy mesons of even or odd parities and a light pseudoscalar meson, within a framework which combines heavy quark effective theory…

High Energy Physics - Phenomenology · Physics 2008-11-26 Svjetlana Fajfer , Jernej Kamenik

Light and heavy-light (b) hadrons are among the most interesting and among the most challenging quantities to calculate in lattice gauge theory. One would like to avoid discretization effects from very heavy quarks and to calculate chiral…

High Energy Physics - Lattice · Physics 2007-05-23 A. Ali Khan

For many years chiral effective theory (ChEFT) has enabled and supported lattice QCD calculations of hadron observables by allowing systematic effects from unphysical lattice parameters to be controlled. In the modern era of precision…

High Energy Physics - Lattice · Physics 2016-11-23 P. E. Shanahan

We present a simple introduction to the techniques of effective field theory (EFT) and their application to QCD. For problems with more than one energy scale, the EFT approach is a useful alternative to more traditional model-building…

Nuclear Theory · Physics 2007-05-23 U. van Kolck , L. J. Abu-Raddad , D. M. Cardamone

We calculate the pion-pion elastic scattering phase shifts for pion masses from the chiral limit to values of interest for lattice studies. At low energies, we use the standard Chiral Perturbation Theory expressions to one and two loops. In…

High Energy Physics - Phenomenology · Physics 2011-10-11 J. Nebreda , J. R. Pelaez , G. Rios

We summarize developments concerning the quark mass dependence of nucleon magnetic moments and the axial-vector coupling constant g_A. The aim is to explore the feasibility of chiral effective field theory methods for the extrapolation of…

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

In this work, we extend and apply effective field theory techniques to systematically understand a subset of lattice artifacts which pollute the lattice correlation functions for a few processes of physical interest. Where possible, we…

High Energy Physics - Lattice · Physics 2007-05-23 Andre Walker-Loud