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As a direct source of information on chiral symmetry breaking within QCD, the sigma commutator is of considerable importance. Since hadron structure is a non-perturbative problem, numerical calculations on a space-time lattice are currently…

Nuclear Theory · Physics 2010-02-17 Stewart V. Wright , Derek B. Leinweber , Anthony W. Thomas

We investigate f_0-sigma mixing in the framework of light cone QCD sum rules and by employing the experimental results about the decay widths and the masses of these scalar mesons we estimate the scalar mixing angle by using sigma meson…

High Energy Physics - Phenomenology · Physics 2009-11-10 A. Gokalp , Y. Sarac , O. Yilmaz

We investigate the electromagnetic mass splittings in the pseudoscalar meson and nucleon systems by combining 2+1 flavor domain wall fermion gauge configurations, generated by the RBC and UKQCD collaborations, and quenched, non-compact,…

High Energy Physics - Lattice · Physics 2010-01-21 Ran Zhou , Thomas Blum , Takumi Doi , Masashi Hayakawa , Taku Izubuchi , Norikazu Yamada

Puzzles in the determination of the hadronic-vacuum-polarization contribution currently impede a conclusive interpretation of the precision measurement of the anomalous magnetic moment of the muon at the Fermilab experiment. One such puzzle…

A method for computing electromagnetic properties of hadrons in lattice QCD is described and preliminary numerical results are presented. The electromagnetic field is introduced dynamically, using a noncompact formulation. Employing…

High Energy Physics - Lattice · Physics 2009-10-28 A. Duncan , E. Eichten , H. Thacker

The remarkable recent progress in the precision of Lattice QCD computations for a number of physical quantities relevant for flavour physics has motivated the introduction of isospin-breaking effects, including in particular electromagnetic…

High Energy Physics - Lattice · Physics 2021-04-21 C. T. Sachrajda

We simulate Lattice QED in a constant external magnetic field using the RHMC algorithm. We seek evidence for chiral symmetry breaking predicted by truncated Schwinger-Dyson methods. Since the predicted values of the dynamical electron mass…

High Energy Physics - Lattice · Physics 2022-10-21 D. K. Sinclair , J. B. Kogut

We study QED in external electromagnetic fields using methods developed for simulating lattice QCD. Our first project is to simulate QED in a constant (in space and time) external magnetic field on a euclidean space-time lattice using the…

High Energy Physics - Lattice · Physics 2021-11-04 D. K. Sinclair , J. B. Kogut

We analyse the two purely isospin-violating decays $\Lambda_b\rightarrow \Sigma^0 \phi$ and $\Lambda_b\rightarrow \Sigma^0 J/\psi$, proceed merely via the exchange topologies, in the framework of perturbative QCD approach. Assuming…

High Energy Physics - Phenomenology · Physics 2023-08-28 Zhou Rui , Jia-Ming Li , Chao-Qi Zhang

The topology of the ground state of QCD manifests itself through the dependence of its potential energy density on the CP-violating angle $\Theta$. This is computed in the present note within a three-flavor linear meson model. It is shown…

High Energy Physics - Phenomenology · Physics 2026-02-27 András Patkós

Using the Coulomb gauge formulation of QED we present a lattice QCD procedure to calculate the $\pi^+\pi^+$ scattering phase shift including the effects of the Coulomb potential which appears in this formulation. The approach described here…

High Energy Physics - Lattice · Physics 2022-08-31 Norman Christ , Xu Feng , Joseph Karpie , Tuan Nguyen

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 $\approx…

A lattice QCD computation of the coupled channel $\pi\Sigma-\bar{K}N$ scattering amplitudes in the $\Lambda(1405)$ region is detailed. Results are obtained using a single ensemble of gauge field configurations with $N_{\rm f} = 2+1$…

At the precision reached in current lattice QCD calculations, electromagnetic effects are becoming numerically relevant. Here, electromagnetic effects are included by superimposing $\mathrm{U}(1)$ degrees of freedom on $N_f = 2+1$ QCD…

The \Sigma^0-\Lambda mixing angle in isospin-asymmetric nuclear medium is investigated by using QCD sum rules. From the general consideration of the in-medium baryonic correlations, in-medium baryon mixings are shown to have several Lorentz…

High Energy Physics - Phenomenology · Physics 2009-11-07 N. Yagisawa , T. Hatsuda , A. Hayashigaki

The mass splittings in the pseudoscalar mesons are studied by combining 2+1 flavor domain wall fermion gauge configurations, generated by the RBC/UKQCD collaborations, and quenched, non-compact, lattice QED configurations. We extract the…

High Energy Physics - Lattice · Physics 2010-11-05 Ran Zhou , Shunpei Uno

We report on the physical-point RBC/UKQCD calculation of the leading isospin-breaking corrections to light-meson leptonic decays. This is highly relevant for future precision tests in the flavour physics sector, in particular the first-row…

In this work, we perform a QCD sum rules analysis on the $\Xi_{Q}-\Xi_{Q}^{\prime}$ mixing. Contributions from up to dimension-6 four-quark operators are considered. However, it turns out that, only dimension-4 and dimension-5 operators…

High Energy Physics - Phenomenology · Physics 2023-12-05 Xiao-Yu Sun , Fu-Wei Zhang , Yu-Ji Shi , Zhen-Xing Zhao

Recent experimental results for the reaction \gamma + p \to K^+ + \Sigma + \pi\ from CLAS at Jefferson Lab are discussed. It was found that the mass distributions or "line shapes" of the three charge combinations \Sigma^+ \pi^-, \Sigma^0…

Nuclear Experiment · Physics 2015-06-15 Reinhard A. Schumacher , Kei Moriya

We report on a calculation of the effects of isospin breaking in Lattice QCD+QED. This involves using Chiral Perturbation Theory with Electromagnetic corrections to find the renormalized, non-degenerate, light quark masses. The calculations…

High Energy Physics - Lattice · Physics 2013-12-03 Shane Drury , Thomas Blum , Masashi Hayakawa , Taku Izubuchi , Chris Sachrajda , Ran Zhou