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We compute the neutral pion mass dependence on a magnetic field in the weak field approximation at one-loop order. The calculation is carried out within the linear sigma model coupled to quarks and using Schwinger's proper-time…

High Energy Physics - Phenomenology · Physics 2018-12-19 Alejandro Ayala , Ricardo L. S. Farias , S. Hernandez-Ortiz , Luis A. Hernandez , D. Manreza Paret , R. Zamora

We present and test a new method to compute the hadronic vacuum polarization function in lattice simulations. This can then be used, e.g., to determine the leading hadronic contribution to the anomalous magnetic moment of the muon. The…

High Energy Physics - Lattice · Physics 2015-09-30 Gunnar Bali , Gergely Endrodi

The covariant propagator of a fermion with intrinsic magnetic moment interacting with a uniform external magnetic field is presented for finite temperature and baryonic density. The case of a scalar boson is also considered. The final…

Nuclear Theory · Physics 2017-05-04 R. Aguirre

The value of the pion polarizability is predicted with high precision by Chiral Perturbation Theory. However, the existing experimental values are at tension with this prediction as well as among themselves. The COMPASS experiment at the…

High Energy Physics - Experiment · Physics 2014-02-13 Stefan Huber

By simulating a uniform electric field on a lattice and measuring the change in the rest mass, we calculate the electric polarizability of neutral mesons and baryons using the methods of quenched lattice QCD. Specifically, we measure the…

High Energy Physics - Lattice · Physics 2008-11-26 Joe Christensen , Walter Wilcox , Frank X. Lee , Leming Zhou

The effective masses of the neutral mesons in a hadronic medium and under an external magnetic field are evaluated as functions of the baryonic density and the field intensity. For this purpose the meson polarization is evaluated in the one…

Nuclear Theory · Physics 2017-11-27 R. M. Aguirre

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

The electric alpha and magnetic beta pion Compton polarizabilities characterize the pion's deformation in the electromagnetic field of the gamma during gamma-pi Compton scattering. The chi_PT effective Lagrangian, using data from radiative…

High Energy Physics - Experiment · Physics 2007-05-23 Murray Moinester

We present a lattice QCD calculation of the nucleon electric polarizabilities at the physical pion mass. Our findings reveal the substantial contributions of the $N\pi$ states to these polarizabilities. Without considering these…

High Energy Physics - Lattice · Physics 2024-09-02 Xuan-He Wang , Zhao-Long Zhang , Xiong-Hui Cao , Cong-Ling Fan , Xu Feng , Yu-Sheng Gao , Lu-Chang Jin , Chuan Liu

Direct evaluation of charged particle polarizabilities on the lattice is quite difficult. However, a short cut for charged pion polarizability - the Das, Mathur, Okubo Sum Rule - can readily be calculated using lattice techniques. A…

High Energy Physics - Lattice · Physics 2009-10-28 Walter Wilcox

We calculate the neutral pion mass in the presence of an external magnetic field of arbitrary strength in the framework of the linear sigma model coupled to quarks at zero temperature. We find nonmonotonic behavior of the pion mass as a…

High Energy Physics - Phenomenology · Physics 2020-04-29 Aritra Das , Najmul Haque

We present a valence calculation of the electric polarizability of the neutron, neutral pion, and neutral kaon on two dynamically generated nHYP-clover ensembles. The pion masses for these ensembles are 227(2) MeV and 306(1) MeV, which are…

High Energy Physics - Lattice · Physics 2014-04-18 Michael Lujan , Andrei Alexandru , Walter Freeman , Frank Lee

Recent attempts to determine the pion polarizability by dispersion relations yield values that disagree with the predictions of chiral perturbation theory. These dispersion relations are based on specific forms for the absorptive part of…

High Energy Physics - Phenomenology · Physics 2014-11-20 B. Pasquini , D. Drechsel , S. Scherer

The extrapolation of nucleon magnetic form factors calculated within lattice QCD is investigated within a framework based upon heavy baryon chiral effective-field theory. All one-loop graphs are considered at arbitrary momentum transfer and…

High Energy Physics - Phenomenology · Physics 2008-11-26 P. Wang , D. B. Leinweber , A. W. Thomas , R. D. Young

We use the linear sigma model with quarks to find the magnetic field-induced modifications to the neutral pion mass at one-loop level. The magnetic field effects are introduced by using charged particle propagators in the presence of a…

High Energy Physics - Phenomenology · Physics 2021-03-31 Alejandro Ayala , José Luis Hernández , L. A. Hernández , Ricardo L. S. Farias , R. Zamora

Formulas are developed for use in lattice studies of charged hadron polarizabilities. In particular, the valence quark different-flavor component of the charged pion polarizability is examined on a $16^{3}\times 24$ lattice at $\beta=6.0$…

High Energy Physics - Lattice · Physics 2009-10-28 Walter Wilcox

The application of a uniform background magnetic field makes standard quark operators utilising gauge-covariant Gaussian smearing inefficient at isolating the ground state nucleon at nontrivial field strengths. In the absence of QCD…

High Energy Physics - Lattice · Physics 2018-09-03 Ryan Bignell , Jonathan Hall , Waseem Kamleh , Derek Leinweber , Matthias Burkardt

We present results for the charged and neutral pion polarizabilities, obtained through a dispersive analysis of photon-fusion reactions with two pions in the final state. This analysis is motivated by current and future measurements at…

High Energy Physics - Phenomenology · Physics 2024-08-01 Viktoriia Ermolina , Igor Danilkin , Marc Vanderhaeghen

The quark-connected part of the hadronic light-by-light scattering contribution to the muon's anomalous magnetic moment is computed using lattice QCD with chiral fermions. We report several significant algorithmic improvements and…

High Energy Physics - Lattice · Physics 2016-01-20 Thomas Blum , Norman Christ , Masashi Hayakawa , Taku Izubuchi , Luchang Jin , Christoph Lehner

Background field methods provide an important nonperturbative formalism for the determination of hadronic properties which are complementary to matrix-element calculations. However, new challenges are encountered when utilising a fermion…

High Energy Physics - Lattice · Physics 2020-05-20 Ryan Bignell , Waseem Kamleh , Derek Leinweber