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Flavor singlet and non-singlet axial Ward identities are investigated using the Wilson formulation of lattice QCD with Clover O(a)-improvement, which breaks explicitly chiral symmetry. The matching at one-loop order of all the relevant…

High Energy Physics - Lattice · Physics 2015-06-25 D. Guadagnoli , S. Simula

We formulate chiral gauge theories non-perturbatively, using two different cuttoffs for the fermions and gauge bosons. We use a lattice with spacing $b$ to regulate the gauge fields in standard fashion, while computing the chiral fermion…

High Energy Physics - Phenomenology · Physics 2009-09-15 Pilar Hernandez , Raman Sundrum

We report new results for a frequently discussed gauge theory with twelve fermion flavors in the fundamental representation of the SU(3) color gauge group. The model, controversial with respect to its conformality, is important in…

High Energy Physics - Lattice · Physics 2015-05-27 Zoltan Fodor , Kieran Holland , Julius Kuti , Daniel Nogradi , Chris Schroeder

A lattice regularization procedure for gauge theories is proposed in which fermions are given a special treatment such that all chiral flavor symmetries that are free of Adler-Bell-Jackiw anomalies are kept intact. There is no doubling of…

High Energy Physics - Theory · Physics 2009-10-28 G. 't Hooft

In these lectures I explain how chiral symmetry of continuum QCD naturally leads to a class of lattice regularisations known as twisted mass QCD (tmQCD). As compared to standard Wilson quarks, its advantages are the absence of unphysical…

High Energy Physics - Lattice · Physics 2017-08-23 Stefan Sint

In the last few years it has been proposed a one-dimensional factorization of the fermion determinant in lattice QCD with Wilson-type fermions that leads to a block-local action of the auxiliary bosonic fields. Here we propose a…

High Energy Physics - Lattice · Physics 2022-04-20 Leonardo Giusti , Matteo Saccardi

We perform perturbative computations in a lattice gauge theory with a conformal measure that is quadratic in a non-compact abelian gauge field and is nonlocal, as inspired by the induced gauge action in massless QED$_3$. In a previous work,…

High Energy Physics - Lattice · Physics 2023-01-11 Nikhil Karthik , Matthew Klein , Rajamani Narayanan

Because the propagators of flavor-singlet states incorporate disconnected diagrams, they are uniquely sensitive to any differences in the actions governing sea and valence fermions on the lattice. As such, they present an important test of…

High Energy Physics - Lattice · Physics 2009-11-11 Eric B. Gregory , Alan Irving , Craig McNeile , Steven Miller , Zbyszek Sroczynski

Gauge theories, through the local symmetry which is in their core, exhibit many local constraints, that must be taken care of and addressed in any calculation. In the Hamiltonian picture this is phrased through the Gauss laws, local…

Quantum Physics · Physics 2019-07-18 Erez Zohar , J. Ignacio Cirac

A few years ago the use of standard functional manipulations was demonstrated to imply an unexpected property satisfied by the fermionic Green's functions of QCD, and called effective locality. This feature of QCD is non-perturbative as it…

High Energy Physics - Theory · Physics 2019-10-17 Thierry Grandou , Peter H. Tsang

The first observation is made of hadronic string breaking due to dynamical fermions in zero temperature lattice QCD. The simulations are done for SU(2) color in three dimensions, with two flavors of staggered fermions. The results have…

High Energy Physics - Lattice · Physics 2009-10-31 H. D. Trottier

We study infrared conformality of the twelve-flavor QCD on the lattice. Utilizing the highly improved staggered quarks (HISQ) type action which is useful to study the continuum physics, we analyze the lattice data of the mass and the decay…

We present preliminary results from exploring the phase diagram of finite temperature QCD with three degenerate flavors and with two light flavors and the mass of the third held approximately at the strange quark mass. We use an order…

High Energy Physics - Lattice · Physics 2008-11-26 C. Bernard , T. Burch , S. Datta , T. A. DeGrand , C. E. DeTar , Steven Gottlieb , U. M. Heller , K. Orginos , R. L. Sugar , D. Toussaint

We present preliminary results from exploring the phase diagram of finite temperature QCD with three degenerate flavors and with two light flavors and the mass of the third held approximately at the strange quark mass. We use an order…

High Energy Physics - Lattice · Physics 2008-11-26 C. Bernard , T. Burch , S. Datta , T. A. DeGrand , C. E. DeTar , Steven Gottlieb , U. M. Heller , K. Orginos , R. L. Sugar , D. Toussaint

In order to model pions of two-flavor QCD we consider a lattice field theory involving two flavors of staggered quarks interacting strongly with U(1) gauge fields. For massless quarks, this theory has an $SU_L(2)\times SU_R(2) \times…

High Energy Physics - Lattice · Physics 2008-11-26 D. J. Cecile , Shailesh Chandrasekharan

We propose a novel approach to the Graphene system using a local field theory of 4 dimensional QED model coupled to 2+1 dimensional Dirac fermions, whose velocity is much smaller than the speed of light. Performing hybrid Monte Carlo…

High Energy Physics - Lattice · Physics 2012-06-11 E. Shintani , T. Onogi

We study various improved staggered quark Dirac operators on quenched gluon backgrounds in lattice QCD. We find a clear separation of the spectrum of eigenvalues into high chirality, would-be zero modes and others, in accordance with the…

High Energy Physics - Lattice · Physics 2015-06-25 E. Follana , A. Hart , C. T. H. Davies

A lattice action for QED is considered, where the derivatives in the Dirac operator are replaced by one-sided lattice differences. A systematic expansion in the lattice spacing of the one-loop contribution to the fermion self energy, vacuum…

High Energy Physics - Lattice · Physics 2016-08-24 Neda Sadooghi , Heinz J. Rothe

We argue that lattice simulations of full QCD with varying quark mass are best conducted at fixed lattice spacing rather than at fixed $\beta$. We present techniques which enable this to be carried out effectively, namely the tuning in bare…

High Energy Physics - Lattice · Physics 2009-10-31 Alan C. Irving , UKQCD Collaboration

The mechanism where flavor symmetry is broken spontaneously is discussed within a scalar QCD model with effective three-meson couplings. For sufficiently large coupling the model is unstable with respect to quantum loops from mesonic vacuum…

High Energy Physics - Phenomenology · Physics 2007-05-23 Nils A. Tornqvist