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Related papers: Nucleon form factors and structure functions

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The calculation of the nucleon strangeness form factors from N_f=2+1 clover fermion lattice QCD is presented. Disconnected insertions are evaluated using the Z(4) stochastic method, along with unbiased subtractions from the hopping…

High Energy Physics - Lattice · Physics 2015-05-20 Takumi Doi , Mridupawan Deka , Shao-Jing Dong , Terrence Draper , Keh-Fei Liu , Devdatta Mankame , Nilmani Mathur , Thomas Streuer

We present results on the nucleon tensor form factors and first moment of the transversity distribution using maximally twisted mass fermions. We analyze two Nf=2+1+1 ensembles having pion masses of 213 MeV and 373 MeV with lattice spacing…

High Energy Physics - Lattice · Physics 2013-11-20 Constantia Alexandrou , Martha Constantinou , Karl Jansen , Giannis Koutsou , Haralambos Panagopoulos

Results on the electromagnetic form factors of the nucleon using twisted mass fermion configurations are presented. These include a gauge field ensemble simulated with two degenerate light quarks yielding a pion mass of around 130 MeV, as…

The QCDSF/UKQCD collaboration has an ongoing program to calculate nucleon matrix elements with two flavours of dynamical O(a) improved Wilson fermions. Here we present recent results on the electromagnetic form factors, the quark momentum…

High Energy Physics - Lattice · Physics 2008-11-26 M. Göckeler , Ph. Hägler , R. Horsley , Y. Nakamura , D. Pleiter , P. E. L. Rakow , A. Schäfer , G. Schierholz , W. Schroers , H. Stüben , J. M. Zanotti

We present preliminary results on the electromagnetic form factors and axial charge of the nucleon from ensembles generated by the CLS effort with $N_\mathrm{f}=2+1$ flavours of non-perturbatively $\mathrm{O}(a)$-improved Wilson fermions…

High Energy Physics - Lattice · Physics 2015-11-25 Dalibor Djukanovic , Tim Harris , Georg von Hippel , Parikshit Junnarkar , Harvey B. Meyer , Hartmut Wittig

We present an update of our analysis of statistical and systematic errors in the calculation of iso-vector scalar, axial and tensor charges of the nucleon. The calculations are done using $N_f=2+1+1$ flavor HISQ ensembles generated by the…

High Energy Physics - Lattice · Physics 2016-01-11 Rajan Gupta , Tanmoy Bhattacharya , Vincenzo Cirigliano , Huey-Wen Lin , Boram Yoon

The electromagnetic form factors have attracted lot of theoretical and experimental attention recently as they encode extensive information on the internal structure of the hadron. An understanding of the form factors is necessary to…

High Energy Physics - Phenomenology · Physics 2011-08-02 Harleen Dahiya , Neetika Sharma

It is imperative that lattice QCD serve to develop our understanding of hadron structure and, where possible, to guide the interpretation of experimental data. There is now a great deal of effort directed at the calculation of the…

High Energy Physics - Lattice · Physics 2010-02-17 J. D. Ashley , D. B. Leinweber , A. W. Thomas , R. D. Young

We report on our on-going study of the lower moments of iso-vector polarised and unpolarised structure functions, $g_A$ and $\langle x\rangle_{u-d}$, respectively, and the iso-vector scalar and tensor charge, for $N_f=2$ non-perturbatively…

High Energy Physics - Lattice · Physics 2013-11-28 G. S. Bali , S. Collins , B. Gläßle , M. Göckeler , J. Najjar , R. Rödl , A. Schäfer , R. Schiel , A. Sternbeck , W. Söldner

We determine generalized form factors of the nucleon from lattice simulations with $N_f = 2$ mass-degenerate non-perturbatively improved Wilson-Sheikholeslami-Wohlert fermions down to a pion mass of 150 MeV. We also present the resulting…

High Energy Physics - Lattice · Physics 2016-01-20 Gunnar Bali , Sara Collins , Meinulf Göckeler , Rudolf Rödl , Andreas Schäfer , Andre Sternbeck

We analyze the electromagnetic form factors of the nucleon to fourth order in relativistic baryon chiral perturbation theory. We employ the recently proposed infrared regularization scheme and show that the convergence of the chiral…

High Energy Physics - Phenomenology · Physics 2009-10-31 Bastian Kubis , Ulf-G. Meißner

We present the nucleon axial and electromagnetic form factors using \Nf{2}{1}{1} ensembles of twisted mass fermions with clover improvement and with masses tuned to their physical values. Excited state effects are studied using several…

We apply the perturbative chiral quark model at one loop to calculate the strange form factors of the nucleon. A detailed numerical analysis of the strange magnetic moments and radii of the nucleon, and also the momentum dependence of the…

High Energy Physics - Phenomenology · Physics 2009-11-07 V. E. Lyubovitskij , P. Wang , Th. Gutsche , Amand Faessler

The electromagnetic and axial form factors of the nucleon are evaluated in twisted mass QCD with two degenerate flavors of light, dynamical quarks. The axial charge g_A, magnetic moment and the Dirac and Pauli radii are determined for pion…

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

The RBC and UKQCD collaborations have been investigating hadron physics in numerical lattice quantum chromodynamics (QCD) with (2+1) flavors of dynamical domain wall fermions (DWF) quarks that preserves continuum-like chiral and flavor…

High Energy Physics - Lattice · Physics 2019-08-15 Shigemi Ohta

We report isovector form factors and low moments of structure functions of nucleon in numerical lattice quantum chromodynamics (QCD) from the on-going calculations by the RIKEN-BNL-Columbia (RBC) and UKQCD Collaborations with (2+1)…

High Energy Physics - Lattice · Physics 2012-08-27 UKQCD Collaboration , Takeshi Yamazaki , Shigemi Ohta

We present results for the nucleon electromagnetic and axial form factors using an N$_f$=2 twisted mass fermion ensemble with pion mass of about 131 MeV. We use multiple sink-source separations to identify excited state contamination.…

Moments of unpolarized, helicity, and transversity distributions, electromagnetic form factors, and generalized form factors of the nucleon are presented from a preliminary analysis of lattice results using pion masses down to 359 MeV. The…

High Energy Physics - Lattice · Physics 2014-11-17 R. G. Edwards , G. Fleming , Ph. Hagler , J. W. Negele , K. Orginos , A. V. Pochinsky , D. B. Renner , D. G. Richards , W. Schroers

We compute the nucleon axial and induced pseudoscalar form factors using three ensembles of gauge configurations, generated with dynamical light quarks with mass tuned to approximately their physical value. One of the ensembles also…