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A massless up quark is an intriguing solution to the strong CP problem. We discuss how lattice computations can be used in conjunction with chiral perturbation theory to address the consistency of $m_u=0$ with the observed hadron spectrum…

High Energy Physics - Lattice · Physics 2010-02-03 Andrew G. Cohen , David B. Kaplan , Ann E. Nelson

We perform hybrid Monte Carlo simulation of (2+1+1)-flavors lattice QCD with the optimal domain-wall fermion (which has the effective 4D Dirac operator exactly equal to the Zolotarev optimal rational approximation of the overlap Dirac…

High Energy Physics - Lattice · Physics 2017-02-09 Yu-Chih Chen , Ting-Wai Chiu

A method for computing all-point quark propagators is applied to a variety of processes of physical interest in lattice QCD. The method allows, for example, efficient calculation of disconnected parts and full momentum-space 2 and 3 point…

High Energy Physics - Lattice · Physics 2015-06-25 A. Duncan , E. Eichten , J. Yoo

We study the valence approximation in lattice QCD of hadrons where the cloud quarks and antiquarks are deleted by truncating the backward time propagation (Z graphs) in the connected insertions. Whereas, the sea quarks are eliminated via…

High Energy Physics - Lattice · Physics 2009-09-25 Keh-Fei Liu , Shao-Jing Dong

Quantum error correction (QEC) is required for large-scale computation, but incurs a significant resource overhead. Recent advances have shown that by jointly decoding logical qubits in algorithms composed of transversal gates, the number…

We show how to compute electromagnetic polarizabilities of charged hadrons using four-point functions in lattice QCD. The low-energy behavior of Compton scattering amplitude is matched to matrix elements of current-current correlation…

High Energy Physics - Lattice · Physics 2022-01-03 Walter Wilcox , Frank X. Lee

Although QUDA allows for an efficient computation of many QCD quantities, it is surprinsingly lacking tools to evaluate disconnected diagrams, for which GPUs are specially well suited. We aim to fill this gap by creating our own branch of…

High Energy Physics - Lattice · Physics 2014-02-03 Constantia Alexandrou , Kyriacos Hadjiyiannakou , Giannis Koutsou , Alexei Strelchenko , Alejandro Vaquero

In order to develop fast inversion algorithms we have used overlap solvers in two dimensions. Lattice QED theory with U(1) group symmetry in two dimensional space-times dimensions has always been a testing ground for algorithms. By the…

High Energy Physics - Lattice · Physics 2014-06-25 Dafina Xhako , Artan Boriçi

The distributions of the quark number and chiral condensate over the gauge fields are computed for QCD in Euclidean space at nonzero quark chemical potential. As both operators are non-hermitian the distributions are in the complex plane.…

High Energy Physics - Lattice · Physics 2014-11-20 M. P. Lombardo , K. Splittorff , J. J. M. Verbaarschot

Perturbative expansions of several small Wilson loops are computed through next-to-next-to-leading order in unquenched lattice QCD, from Monte Carlo simulations at weak couplings. This approach provides a much simpler alternative to…

High Energy Physics - Lattice · Physics 2009-11-11 Kit Yan Wong , Howard D. Trottier , R. M. Woloshyn

In this talk we discuss the color decomposition of tree-level and one-loop QCD amplitudes with arbitrary numbers of quarks and gluons. We present a method for the decomposition of partial amplitudes into primitive amplitudes, which is based…

High Energy Physics - Phenomenology · Physics 2014-07-03 Christian Reuschle , Stefan Weinzierl

We present high-statistics estimates of the isovector charges of the nucleon from four 2+1-flavor ensembles generated using Wilson-clover fermions with stout smearing and tree-level tadpole improved Symanzik gauge action at lattice spacings…

Recent developments in lattice QCD calculation of flavor singlet nucleon matrix elements are reviewed. Substantial sea quark contributions are found in the $\pi$-$N\ \sigma$ term and the quark spin content of the nucleon such that the total…

High Energy Physics - Lattice · Physics 2009-10-28 Masanori Okawa

The computational requirements and dynamics of Monte Carlo simulations of unquenched QCD incorporating the infrared quark eigenmodes (up to $\approx \Lambda_{QCD}$) exactly and UV modes via a loop representation are discussed. The accuracy…

High Energy Physics - Lattice · Physics 2015-06-25 A. Duncan , E. Eichten , H. Thacker

We study the density of states method to explore the phase diagram of the chiral transition on the tempeature and quark chemical potential plane. Four quark flavours are used in the analysis. Though the method is quite expensive small…

High Energy Physics - Lattice · Physics 2009-09-29 Christian Schmidt , Zoltan Fodor , Sandor Katz

We present results on the quark unpolarized, helicity and transversity parton distributions functions of the nucleon. We use the quasi-parton distribution approach within the lattice QCD framework and perform the computation using an…

High Energy Physics - Lattice · Physics 2021-09-22 Constantia Alexandrou , Martha Constantinou , Kyriakos Hadjiyiannakou , Karl Jansen , Floriano Manigrasso

The low-lying eigenvalue spectrum of the QCD Dirac operator in the epsilon-regime is expected to match with that of chiral Random Matrix Theory (ChRMT). We study this correspondence for the case including sea quarks by performing two-flavor…

High Energy Physics - Lattice · Physics 2012-08-27 JLQCD , TWQCD collaboration , : , H. Fukaya , S. Aoki , T. W. Chiu , S. Hashimoto , T. Kaneko , H. Matsufuru , J. Noaki , K. Ogawa , T. Onogi , N. Yamada

The K+K+ scattering length is calculated in fully-dynamical lattice QCD with domain-wall valence quarks on the MILC asqtad-improved gauge configurations with rooted staggered sea quarks. Three-flavor mixed-action chiral perturbation theory…

High Energy Physics - Lattice · Physics 2008-11-26 Silas Beane , Thomas Luu , Kostas Orginos , Assumpta Parreno , Martin Savage , Aaron Torok , Andre Walker-Loud

The possibility of treating colour in one-loop amplitude calculations alike the other quantum numbers is briefly discussed for semi-numerical algorithms based on generalized unitarity and parametric integration techniques. Numerical results…

High Energy Physics - Phenomenology · Physics 2015-03-17 Jan Winter

We present the complete 1-loop perturbative computation of the renormalization constants and mixing coefficients of the operators that measure the first moment of deep inelastic scattering structure functions, employing the nearest neighbor…

High Energy Physics - Lattice · Physics 2009-10-22 Stefano Capitani , Giancarlo Rossi