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Related papers: Nucleon generalized form factors with twisted mass…

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We present the first lattice calculation of nucleon matrix elements using four dynamical flavors. We use the $N_f=2+1+1$ maximally twisted mass formulation. The renormalization is performed non-perturbatively in the RI$^\prime$-MOM scheme…

High Energy Physics - Lattice · Physics 2015-03-18 Simon Dinter , Constantia Alexandrou , Martha Constantinou , Vincent Drach , Karl Jansen , Dru Renner

We present results on the spin and quark content of the nucleon using $N_f=2$ twisted mass clover-improved fermion simulations with a pion mass close to its physical value. We use recently developed methods to obtain accurate results for…

High Energy Physics - Lattice · Physics 2016-11-29 C. Alexandrou , M. Constantinou , K. Hadjiyiannakou , Ch. Kallidonis , G. Koutsou , K. Jansen , Ch. Wiese , A. Vaquero Avilés-Casco

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 compute the electromagnetic form factors of the proton and neutron using lattice QCD with $N_f = 2 + 1 + 1$ twisted mass clover-improved fermions and quark masses tuned to their physical values. Three ensembles with lattice spacings of…

High Energy Physics - Lattice · Physics 2025-02-18 Constantia Alexandrou , Simone Bacchio , Giannis Koutsou , Bhavna Prasad , Gregoris Spanoudes

We present results on the lower moments of the nucleon generalized parton distri butions within lattice QCD using two dynamical flavors of degenerate twisted mass fermions. Our simulations are performed on lattices with three different…

High Energy Physics - Lattice · Physics 2011-07-05 C. Alexandrou , J. Carbonell , M. Constantinou , P. A. Harraud , P. Guichon , K. Jansen , C. Kallidonis , T. Korzec , M. Papinutto

We compute the nucleon axial and pseudoscalar form factors using three $N_f=$2+1+1 twisted mass fermion ensembles with all quark masses tuned to approximately their physical values. The values of the lattice spacings of these three physical…

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

In this lattice QCD study we evaluate the nucleon spin decomposition to quarks and gluons contributions. We employ one gauge ensemble of maximally twisted mass fermions with two degenerate light quarks tuned to approximately reproduce the…

We present results on the nucleon electromagnetic form factors from Lattice QCD at momentum transfer up to about $12$~GeV$^2$. We analyze two gauge ensembles with the Wilson-clover fermion action, a lattice spacing of $a\approx 0.09$~fm and…

High Energy Physics - Lattice · Physics 2018-10-11 Christos Kallidonis , Sergey Syritsyn , Michael Engelhardt , Jeremy Green , Stefan Meinel , John Negele , Andrew Pochinsky

We investigate scalar matrix elements of the nucleon using $N_f=2+1+1$ flavors of maximally twisted mass fermions at a fixed value of the lattice spacing of $a\approx 0.078{\rm fm}$. We compute disconnected contributions to the relevant…

High Energy Physics - Lattice · Physics 2012-02-17 S. Dinter , V. Drach , K. Jansen

We present results for the nucleon electromagnetic form factors using an ensemble of maximally twisted mass clover-improved fermions with pion mass of about 130 MeV. We use multiple sink-source separations and three analysis methods to…

We present an update on our results of nucleon form factors measured on a large-volume lattice $(8.1\rm{fm})^4$ at almost the physical point in 2+1 flavor QCD. The configurations are generated with the stout-smeared $\mathcal{O}(a)$…

High Energy Physics - Lattice · Physics 2018-04-18 Natsuki Tsukamoto , Ken-Ichi Ishikawa , Yoshinobu Kuramashi , Shoichi Sasaki , Takeshi Yamazaki

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 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 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…

With a special intention of clarifying the underlying spin contents of the nucleon, we investigate the generalized form factors of the nucleon, which are defined as the $n$-th $x$-moments of the generalized parton distribution functions,…

High Energy Physics - Phenomenology · Physics 2008-11-26 M. Wakamatsu , Y. Nakakoji

We report our numerical lattice QCD calculations of the isovector nucleon form factors for the vector and axialvector currents: the vector, induced tensor, axialvector, and induced pseudoscalar form factors. The calculation is carried out…

High Energy Physics - Lattice · Physics 2010-04-28 Takeshi Yamazaki , Yasumichi Aoki , Tom Blum , Huey-Wen Lin , Shigemi Ohta , Shoichi Sasaki , Robert Tweedie , James Zanotti

We present a calculation of the Mellin moments of the nucleon transverse quark spin densities extracted from the unpolarized and transversity generalized form factors. We use three $N_F=2+1+1$ ensembles of twisted mass fermions with quark…

In order to advance lattice calculations of moments of unpolarized, helicity, and transversity distributions, electromagnetic form factors, and generalized form factors of the nucleon to a new level of precision, this work investigates…

Lattice simulations of QCD have produced precise estimates for the masses of the lowest-lying hadrons which show excellent agreement with experiment. By contrast, lattice results for the vector and axial vector form factors of the nucleon…

High Energy Physics - Lattice · Physics 2011-09-23 B. B. Brandt , S. Capitani , M. Della Morte , D. Djukanovic , J. Gegelia , G. von Hippel , A. Juttner , B. Knippschild , H. B. Meyer , H. Wittig