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We apply Euclidean time methods to phenomenological Dyson-Schwinger models of hadrons. By performing a Fourier transform of the momentum space correlation function to Euclidean time and by taking the large Euclidean time limit, we project…

High Energy Physics - Phenomenology · Physics 2016-09-06 M. Burkardt , M. R. Frank , K. L. Mitchell

In this work we discuss in detail the non-perturbative determination of the momentum dependence of the form factors entering in semileptonic decays using unitarity and analyticity constraints. The method contains several new elements with…

High Energy Physics - Lattice · Physics 2021-09-15 M. Di Carlo , G. Martinelli , M. Naviglio , F. Sanfilippo , S. Simula , L. Vittorio

Heavy-meson semileptonic decays calculations on the lattice are reviewed. The focus is upon obtaining reliable matrix elements. Errors that depend upon the lattice spacing, $a$, are an important source of systematic error. Full $O(a)$…

High Energy Physics - Lattice · Physics 2009-10-28 James Simone

We examine the relation of moments of parton distribution functions to matrix elements of non-local operators computed in lattice quantum chromodynamics. We argue that after the continuum limit is taken, these non-local matrix elements give…

High Energy Physics - Lattice · Physics 2018-12-26 Joseph Karpie , Kostas Orginos , Savvas Zafeiropoulos

We apply the gradient flow on a color-electric two-point function that encodes the heavy quark momentum diffusion coefficient. The simulations are done on fine isotropic lattices in the quenched approximation at $1.5\,T_c$. The continuum…

High Energy Physics - Lattice · Physics 2021-02-02 Luis Altenkort , Alexander M. Eller , Olaf Kaczmarek , Lukas Mazur , Guy D. Moore , Hai-Tao Shu

We present a simultaneous extraction of the moments of $F_2$ and $F_L$ structure functions of the proton for a range of photon virtuality, $Q^2$. This is achieved by computing the forward Compton amplitude on the lattice utilizing the…

We investigate the connection of lattice calculations of moments of isovector parton distributions to the physical regime through extrapolations in the quark mass. We consider the one pion loop renormalisation of the nucleon matrix elements…

High Energy Physics - Lattice · Physics 2009-11-07 W. Detmold , W. Melnitchouk , A. W. Thomas

We calculate the kaon semileptonic form factors using the two sets of the PACS10 configuration, whose physical volumes are more than (10 fm)$^4$ at the physical point. The lattice spacings are 0.063 and 0.085 fm. The configurations were…

We perform a nonperturbative lattice calculation of the complex phase and modulus of the pion form factor in the timelike momentum region using the finite-volume technique. We use two ensembles of 2+1-flavor overlap fermion at pion masses…

High Energy Physics - Lattice · Physics 2015-03-18 Xu Feng , Sinya Aoki , Shoji Hashimoto , Takashi Kaneko

In this work, we report a novel technique in lattice QCD for studying the high momentum-transfer region of nucleon form factors. These calculations could give important theoretical input to experiments, such as those of JLab's 12-GeV…

High Energy Physics - Lattice · Physics 2010-05-06 Huey-Wen Lin , Saul D. Cohen , Robert G. Edwards , Kostas Orginos , David G. Richards

We present a new method to determine the momentum dependence of the N to Delta transition form factors and demonstrate its effectiveness in the quenched theory at $\beta=6.0$ on a $32^3 \times 64$ lattice. We address a number of technical…

High Energy Physics - Lattice · Physics 2008-11-26 C. Alexandrou , Ph. de Forcrand , H. Neff , J. W. Negele , W. Schroers , A. Tsapalis

The two-body decay rate of a weakly decaying particle (such as the kaon) is shown to be proportional to the square of a well-defined transition matrix element in finite volume. Contrary to the physical amplitude, the latter can be extracted…

High Energy Physics - Lattice · Physics 2009-10-31 Laurent Lellouch , Martin Lüscher

We calculate the transition form factor between vector and pseudoscalar quarkonia in both the timelike and the spacelike region using light-front dynamics. We investigate the frame dependence of the form factors for heavy quarkonia with…

Nuclear Theory · Physics 2019-08-19 Meijian Li , Yang Li , Pieter Maris , James P. Vary

We discuss the recently proposed multiboson domain-decomposed factorization of the gauge-field dependence of the fermion determinant in lattice QCD. In particular, we focus on the case of a lattice divided in an arbitrary number of thick…

High Energy Physics - Lattice · Physics 2022-11-22 Marco Cè , Leonardo Giusti , Stefan Schaefer

We discuss the determination of deep-inelastic hadron structure in lattice QCD. By using a fictitious heavy quark, direct calculations of the Compton scattering tensor can be performed in Euclidean space that allow the extraction of the…

High Energy Physics - Lattice · Physics 2008-11-26 William Detmold , C. -J. David Lin

In this work, we present a lattice QCD calculation of the Mellin moments of the twist-2 axial-vector generalized parton distribution (GPD), $\widetilde{H}(x,\xi,t)$, at zero skewness, $\xi$, with multiple values of the momentum transfer,…

We demonstrate how to make rigorous predictions for electroweak matrix elements in nuclear systems directly from QCD. More precisely, we show how to determine the short-distance contributions to low-momentum transfer electroweak matrix…

High Energy Physics - Lattice · Physics 2009-11-10 William Detmold , Martin J. Savage

We show that hadronic matrix elements can be extracted from lattice simulations with background fields that arise from operator exponentiation. Importantly, flavour-singlet matrix elements can be evaluated without requiring the computation…

High Energy Physics - Lattice · Physics 2008-11-26 W. Detmold

We provide an analysis of the x-dependence of the bare unpolarized, helicity and transversity iso-vector parton distribution functions (PDFs) from lattice calculations employing (maximally) twisted mass fermions. The x-dependence of the…

We propose a new approach to compute correlators of quantum fields in de Sitter space. It is based on nonequilibrium field theory techniques, and exploits de Sitter symmetries so as to partially reduce the number of independent variables of…

High Energy Physics - Theory · Physics 2015-06-12 R. Parentani , J. Serreau