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Related papers: Nucleon form factors with light Wilson quarks

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We investigate the imaginary parts of the nucleon electromagnetic and axial form factors close to threshold in the framework of heavy baryon chiral perturbation theory. For the isovector electromagnetic form factors, we recover the well…

High Energy Physics - Phenomenology · Physics 2009-10-28 V. Bernard , N. Kaiser , Ulf-G. Meißner

The firm understanding of standard quark-antiquark states (including excited states) is necessary to search for non-conventional mesons with the same quantum numbers. In this work, we study the phenomenology of two nonets of excited vector…

High Energy Physics - Phenomenology · Physics 2018-08-29 Milena Piotrowska , Francesco Giacosa

Precise proton and neutron form factor measurements at Jefferson Lab, using spin observables, have recently made a significant contribution to the unraveling of the internal structure of the nucleon. Accurate experimental measurements of…

Nuclear Experiment · Physics 2015-06-02 V. Punjabi , C. F. Perdrisat , M. K. Jones , E. J. Brash , C. E. Carlson

We present an update on our lattice calculations of the Mellin moments of PDFs and GPDs for the pion and kaon, using momentum-boosted meson states. In particular, we focus on the calculation of the scalar and tensor local operators, and the…

High Energy Physics - Lattice · Physics 2024-01-09 Joseph Delmar , Constantia Alexandrou , Simone Bacchio , Ian Cloët , Martha Constantinou , Giannis Koutsou

We present a short summary for the calculations of the nucleon $\textit{isovector}$ form factors, which are relevant to improving the accuracy of the current neutrino oscillation experiments. The calculations are carried out with two of…

We present preliminary results from the first calculation of the pion electromagnetic form factor at physical light quark masses. This form factor parameterises the deviations from the behaviour of a point-like particle when a photon hits…

High Energy Physics - Lattice · Physics 2013-11-15 Jonna Koponen , Francis Bursa , Christine Davies , Gordon Donald , Rachel Dowdall

We present results on the nucleon scalar, axial and tensor charges as well as on the momentum fraction, and the helicity and transversity moments. The pion momentum fraction is also presented. The computation of these key observables is…

We present results for the moments of nucleon isovector vector and axial generalised parton distribution functions computed within lattice QCD. Three ensembles of maximally twisted mass clover-improved fermions simulated with a physical…

We present results on the nucleon axial vector form factors $G_A(q^2)$ and $G_p(q^2)$ in the quenched theory and using two degenerate flavors of dynamical Wilson fermions for momentum transfer squared from about 0.1 to about 2 GeV^2 and for…

High Energy Physics - Lattice · Physics 2008-11-26 C. Alexandrou , G. Koutsou , Th. Leontiou , J. W. Negele , A. Tsapalis

The unitarity relations for isovector nucleon form factors in the two-pion approximation for the intermediate states are analytically extended in a model independent way from the real half-axis t > 4 $\mu^2$ ($\mu$ is the pion mass) to the…

Nuclear Theory · Physics 2007-05-23 M. I. Krivoruchenko

We present the isovector axial, induced pseudoscalar, and pseudoscalar form factors of the nucleon using three twisted-mass fermion ensembles with degenerate up- and down-, strange-, and charm-quarks with masses tuned to their physical…

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…

We present the first calculation of the pion electromagnetic form factor at physical light quark masses. This form factor parameterises the deviations from the behaviour of a point-like particle when a photon hits the pion. These deviations…

High Energy Physics - Lattice · Physics 2017-10-23 Jonna Koponen , Francis Bursa , Christine T. H. Davies , Rachel J. Dowdall , G. Peter Lepage

We continue our investigation of the stress within a strongly coupled scalar nucleon, and now dissect the gravitational form factors into contributions from its constituents, the (mock) nucleon and the (mock) pion. The computation is based…

High Energy Physics - Phenomenology · Physics 2025-03-12 Xianghui Cao , Yang Li , James P. Vary

We present new N_f=2 data for the nucleon generalized form factors, varying volume, lattice spacing and pion mass, down to 150 MeV. We also give an update of our direct calculation of the nucleon sigma term for a range of pion mass values…

High Energy Physics - Lattice · Physics 2013-12-04 G. S. Bali , S. Collins , B. Gläßle , M. Göckeler , J. Najjar , R. Rödl , A. Schäfer , R. Schiel , W. Söldner , A. Sternbeck , P. Wein

We determine the generalized form factors, which correspond to the second Mellin moment (i.e., the first $x$-moment) of the generalized parton distributions of the nucleon at leading twist. The results are obtained using lattice QCD with…

High Energy Physics - Lattice · Physics 2019-07-30 Gunnar S. Bali , Sara Collins , Meinulf Göckeler , Rudolf Rödl , Andreas Schäfer , André Sternbeck

We present a comprehensive study of the electromagnetic form factor, the decay constant and the mass of the pion computed in lattice QCD with two degenerate O(a)-improved Wilson quarks at three different lattice spacings in the range…

High Energy Physics - Lattice · Physics 2015-06-16 Bastian B. Brandt , Andreas Juttner , Hartmut Wittig

We present an update of our analysis [1] which includes additional ensembles at different quark masses, lattice spacings and volumes, all with high statistics. We use $N_f=2$ mass-degenerate quark flavours, employing the non-perturbatively…

Proton and neutron electric and magnetic form factors are the primary characteristics of their spatial structure and have been studied extensively over the past half-century. At large values of the momentum transfer $Q^2$ they should reveal…

High Energy Physics - Lattice · Physics 2025-02-25 S. Syritsyn , M. Engelhardt , S. Krieg , J. Negele , A. Pochinsky

We study a model-independent parameterization of the vector pion form factor that arises from the constraints of analyticity and unitarity. Our description should be suitable up to s^(1/2) ~ 1.2 GeV and allows a model-independent…

High Energy Physics - Phenomenology · Physics 2009-11-07 A. Pich , J. Portoles
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