Lattice computation of the electromagnetic contributions to kaon and pion masses
Lattice computation of the electromagnetic contributions to kaon and pion masses
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DOI：
10.1103/physrevd.99.034503
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发表时间：
2019-02-15
影响因子：
5
通讯作者：
Zhou, R.
中科院分区：
文献类型：
--
作者：
Basak, S.;Bazavov, A.;Zhou, R.
本文用格点方法计算了电磁场对轻赝标介子质量的影响。模拟采用了asqtad QCD夸克和猝灭光子的2 + 1动力学性质。晶格间距从约0.12 fm到约0.045 fm不等。我们计算了K+-K-0 EM质量分裂的Dashen定理修正的参数，以及EM对K-0本身质量的贡献的参数。推广了BMW群引入的非微扰EM重整化方案，将EM效应与同位旋破坏的夸克质量效应分开。我们纠正领先的有限体积效应在我们实现的晶格电动力学手征微扰理论，和剩余的有限体积误差相对较小。虽然电猝灭效应在控制范围内，但它们仅在定性上估计为K 0，并构成该数量的最大不确定性来源之一。我们得到了K 0 = 0.78（1）（stat）（（+8）（-11））（syst）和K 0 = 0.035（3）（stat）（20）（syst）。然后将这些结果应用于2 + 1 + 1味纯QCD高度改进交错夸克系综（HISQ），得到m（u）/m（d）= 0.4529（48）（stat）（（+150）（-67））（syst）.
We present a lattice calculation of the electromagnetic (EM) effects on the masses of light pseudoscalar mesons. The simulations employ 2 + 1 dynamical flavors of asqtad QCD quarks and quenched photons. Lattice spacings vary from approximate to 0.12 fm to approximate to 0.045 fm. We compute the quantity epsilon, which parametrizes the corrections to Dashen's theorem for the K+-K-0 EM mass splitting, as well as epsilon(K0), which parametrizes the EM contribution to the mass of the K-0 itself. An extension of the nonperturbative EM renormalization scheme introduced by the BMW group is used in separating EM effects from isospin-violating quark mass effects. We correct for leading finite-volume effects in our realization of lattice electrodynamics in chiral perturbation theory, and remaining finite-volume errors are relatively small. While electroquenched effects are under control for epsilon, they are estimated only qualitatively for epsilon(K0) and constitute one of the largest sources of uncertainty for that quantity. We find epsilon = 0.78(1)(stat)((+8)(-11))(syst) and epsilon(K0) = 0.035(3)(stat)(20)(syst). We then use these results on 2 + 1 + 1 flavor pure QCD highly improved staggered quark (HISQ) ensembles and find m(u)/m(d) = 0.4529(48)(stat)((+150)(-67))(syst).