English
Related papers

Related papers: Efficiently unquenching QCD+QED at O($\alpha$)

200 papers

Electromagnetic effects play an important role in many phenomena such as isospin-symmetry breaking in the hadron spectrum and the hadronic contributions to g-2. We have generalized the MILC QCD code to include the electromagnetic field. In…

High Energy Physics - Lattice · Physics 2014-11-18 Ran Zhou , Steven Gottlieb

We show that maximally twisted mass fermions can be employed to regularize on the lattice the fully unquenched QCD+QED theory with vanishing $\theta$-term. We discuss how the critical mass of the up and down quarks can be conveniently…

High Energy Physics - Lattice · Physics 2016-12-08 Roberto Frezzotti , Giancarlo Rossi , Nazario Tantalo

We present results for the QED and strong isospin breaking corrections to the hadronic vacuum polarization using $N_f=2+1$ Domain Wall fermions. QED is included in an electro-quenched setup using two different methods, a stochastic and a…

High Energy Physics - Lattice · Physics 2018-04-18 Peter Boyle , Vera Gülpers , James Harrison , Andreas Jüttner , Christoph Lehner , Antonin Portelli , Christopher Sachrajda

The effect of sea quark electromagnetic charge on meson masses is investigated, and first results for full QED+QCD low-energy constants are presented. The electromagnetic charge for sea quarks is incorporated in quenched QED+full QCD…

High Energy Physics - Lattice · Physics 2012-08-21 Tomomi Ishikawa , Thomas Blum , Masashi Hayakawa , Taku Izubuchi , Chulwoo Jung , Ran Zhou

We present an exploratory study of leading isospin breaking effects in mesonic masses using $O(a)$ improved Wilson fermions with open boundaries. Isospin symmetry is explicitly broken by distinct masses and electric charges of the up and…

High Energy Physics - Lattice · Physics 2018-11-05 Andreas Risch , Hartmut Wittig

We report a new analysis of the isospin splittings within the decuplet baryon spectrum. Our numerical results are based upon five ensembles of dynamical QCD+QED lattices. The analysis is carried out within a flavour-breaking expansion which…

High Energy Physics - Lattice · Physics 2019-09-05 R. Horsley , Z. Koumi , Y. Nakamura , H. Perlt , D. Pleiter , P. E. L. Rakow , G. Schierholz , A. Schiller , H. Stüben , R. D. Young , J. M. Zanotti

We present an exploratory study of leading isospin breaking effects in mesonic masses using $O(a)$ improved Wilson fermions. Isospin symmetry is explicitly broken by distinct masses and electric charges of the up and down quarks. In order…

High Energy Physics - Lattice · Physics 2018-04-18 Andreas Risch , Hartmut Wittig

The inclusion of electromagnetic effects in unquenched QCD can be accomplished using ensembles generated in dynamical simulations with pure QCD provided the change in the quark determinant induced by a weak electromagnetic field can be…

High Energy Physics - Lattice · Physics 2009-11-10 A. Duncan , E. Eichten , R. Sedgewick

The light hadron spectrum as computed in nonperturbative QCD is reviewed and compared to lattice data and experiment. The mixing of mesons, hybrids and glueballs is calculated in the Field Correlator Method. The strong decay mechanisms are…

High Energy Physics - Phenomenology · Physics 2009-11-10 Yu. A. Simonov

Full QCD+QED simulations allow to evaluate isospin breaking corrections to hadron masses. With the openQxD code, we are able to perform these simulations employing C-periodic boundary conditions, implemented through a doubling of the…

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

In the RC$^\star$ collaboration, we simulate lattice QCD+QED using $C-$periodic spatial boundary conditions to ensure that locality, gauge invariance, and translational invariance are preserved throughout the calculation. We present our…

Lattice QCD simulations are now reaching a precision where electromagnetic corrections from QED become important. In investigating the effects of SU(3) breaking due to quark mass differences within QCD, a group-theoretical analysis of the…

High Energy Physics - Lattice · Physics 2014-06-19 R. Horsley , Y. Nakamura , D. Pleiter , P. E. L. Rakow , G. Schierholz , H. Stüben , R. D. Young , J. M. Zanotti

We present our initial study of the electromagnetic splittings of charged and neutral mesons, and the violation of Dashen's theorem. Hadron masses are calculated on MILC N_f=2+1 QCD ensembles at lattice spacing \approx 0.15fm, together with…

High Energy Physics - Lattice · Physics 2010-01-21 S. Basak , A. Bazavov , C. Bernard , C. DeTar , W. Freeman , Steven Gottlieb , U. M. Heller , J. E. Hetrick , J. Laiho , L. Levkova , J. Osborn , R. Sugar , D. Toussaint

In this contribution, we briefly analyze the formalism of the unquenched quark model (UQM) and its application to the calculation of hadron spectra with self-energy corrections, due to the coupling to the meson-meson continuum. In the UQM,…

High Energy Physics - Phenomenology · Physics 2018-01-03 E. Santopinto , R. Bijker , H. García-Tecocoatzi , J. Ferretti

We discuss some applications of the unquenched quark model which is an extension of the CQM that includes the effects of sea quarks via a 3P0 quark-antiquark pair-creation mechanism. Particular attention is paid to the electromagnetic…

Nuclear Theory · Physics 2017-12-12 Roelof Bijker , Gustavo Guerrero-Navarro , Emmanuel Ortiz-Pacheco

In order to understand QCD at the energies relevant to hadronic physics one requires analytical methods for dealing with relativistic gauge field theories at large couplings. Strongly coupled quenched QED provides an ideal laboratory for…

High Energy Physics - Theory · Physics 2009-10-31 A. W. Schreiber , R. Rosenfelder , C. Alexandrou

We discuss the properties of hadronic fluctuations, i.e. fluctuations of net quark and isospin numbers as well as electric charge, in the vicinity of the QCD transition in isospin-symmetric matter at vanishing quark chemical potential. We…

High Energy Physics - Phenomenology · Physics 2009-11-11 S. Ejiri , F. Karsch , K. Redlich

We discuss a mixed-action approach in which sea quarks are regularised using non-perturbatively ${\rm O}(a)$ improved Wilson fermions, while a fully-twisted tmQCD action is used for valence quarks. In this setup, automatic ${\rm O}(a)$…

High Energy Physics - Lattice · Physics 2018-04-18 Gregorio Herdoíza , Carlos Pena , David Preti , José Ángel Romero , Javier Ugarrio

We have made significant progress on extending lattice QCD calculation of the polarizability of the neutron and other hadrons to include the effects of charged dynamical quarks. This is done by perturbatively reweighting the charges of the…

High Energy Physics - Lattice · Physics 2014-10-20 Walter Freeman , Andrei Alexandru , Mike Lujan , Frank X. Lee
‹ Prev 1 2 3 10 Next ›