scholarly journals Nucleon structure from 2+1 flavor lattice QCD near the physical point

2018 ◽  
Vol 175 ◽  
pp. 06007 ◽  
Author(s):  
Natsuki Tsukamoto ◽  
Ken-Ichi Ishikawa ◽  
Yoshinobu Kuramashi ◽  
Shoichi Sasaki ◽  
Takeshi Yamazaki
Keyword(s):  
Lattice Spacing ◽  
Pion Mass ◽  
Axial Vector ◽  
Form Factors ◽  
Nucleon Structure ◽  
Matrix Elements ◽  
Physical Point ◽  
Nucleon Form Factors ◽  
Pseudo Scalar ◽  
Simulation Point

We present an update on our results of nucleon form factors measured on a large-volume lattice (8:1fm)4 at almost the physical point in 2+1 flavor QCD. The configurations are generated with the stout-smeared O(a) improved Wilson quark action and Iwasaki gauge action at β = 1:82, which corresponds to the lattice spacing of 0.085 fm. The pion mass at the simulation point is about 145 MeV. We determine the isovector electric radius and magnetic moment from nucleon electric (GE) and magnetic (GM) form factors. We also report on preliminary results of the axial-vector (FA), induced pseudo-scalar (FP) and pseudo-scalar (GP) form factors in order to verify the axial Ward-Takahashi identity in terms of the nucleon matrix elements, which may be called as the generalized Goldberger-Treiman relation.

scholarly journals Nucleon structure from 2+1-flavor domain-wall QCD

2018 ◽  
Vol 175 ◽  
pp. 06012 ◽  
Author(s):  
Shigemi Ohta
Keyword(s):  
Domain Wall ◽  
Lattice Spacing ◽  
Pion Mass ◽  
Form Factors ◽  
Nucleon Structure ◽  
Current Form ◽  
Gauge Action ◽  
Domain Wall Fermions ◽  
Quark Momentum ◽  
Structure Calculations

Nucleon-structure calculations of isovector vector-and axialvector-current form factors, transversity and scalar charge, and quark momentum and helicity fractions are reported from two recent 2+1-flavor dynamical domain-wall fermions lattice-QCD ensembles generated jointly by the RIKEN-BNL-Columbia and UKQCD Collaborations with Iwasaki × dislocation-suppressing-determinatn-ratio gauge action at inverse lattice spacing of 1.378(7) GeV and pion mass values of 249.4(3) and 172.3(3) MeV.

scholarly journals Erratum: Nucleon form factors and root-mean-square radii on a (10.8  fm)4 lattice at the physical point [Phys. Rev. D 99 , 014510 (2019)]

2020 ◽  
Vol 102 (1) ◽  
Author(s):  
Eigo Shintani ◽  
Ken-Ichi Ishikawa ◽  
Yoshinobu Kuramashi ◽  
Shoichi Sasaki ◽  
Takeshi Yamazaki ◽  
...  
Keyword(s):  
Root Mean Square ◽  
Form Factors ◽  
Mean Square ◽  
Physical Point ◽  
Nucleon Form Factors

scholarly journals Computation of parton distributions from the quasi-PDF approach at the physical point

2018 ◽  
Vol 175 ◽  
pp. 14008 ◽  
Author(s):  
Constantia Alexandrou ◽  
Simone Bacchio ◽  
Krzysztof Cichy ◽  
Martha Constantinou ◽  
Kyriakos Hadjiyiannakou ◽  
...  
Keyword(s):  
Pion Mass ◽  
Distribution Functions ◽  
Matrix Elements ◽  
Parton Distribution Functions ◽  
Physical Point ◽  
Parton Distributions ◽  
The Matrix ◽  
First Results ◽  
Perturbative Renormalization ◽  
Vector Combination

We show the first results for parton distribution functions within the proton at the physical pion mass, employing the method of quasi-distributions. In particular, we present the matrix elements for the iso-vector combination of the unpolarized, helicity and transversity quasi-distributions, obtained with Nf = 2 twisted mass cloverimproved fermions and a proton boosted with momentum [see formula in PDF] = 0.83 GeV. The momentum smearing technique has been applied to improve the overlap with the proton boosted state. Moreover, we present the renormalized helicity matrix elements in the RI’ scheme, following the non-perturbative renormalization prescription recently developed by our group.

scholarly journals D → π and D → K semileptonic form factors with Nf = 2 + 1 + 1 twisted mass fermions

2018 ◽  
Vol 175 ◽  
pp. 13026
Author(s):  
Vittorio Lubicz ◽  
Lorenzo Riggio ◽  
Giorgio Salerno ◽  
Silvano Simula ◽  
Cecilia Tarantino
Keyword(s):  
Pion Mass ◽  
Form Factors ◽  
Kinematical Region ◽  
Matrix Elements ◽  
Scalar Form ◽  
Mass Collaboration ◽  
Twisted Mass ◽  
The Matrix ◽  
Additional Form

We present a lattice determination of the vector and scalar form factors of the D → π(K)lv semileptonic decays, which are relevant for the extraction of the CKM matrix elements |Vcd| and |Vcs| from experimental data. Our analysis is based on the gauge configurations produced by the European Twisted Mass Collaboration with Nf = 2 + 1 +1 flavors of dynamical quarks. We simulated at three different values of the lattice spacing and with pion masses as small as 210 MeV. The matrix elements of both vector and scalar currents are determined for a plenty of kinematical conditions in which parent and child mesons are either moving or at rest. Lorentz symmetry breaking due to hypercubic effects is clearly observed in the data and included in the decomposition of the current matrix elements in terms of additional form factors. After the extrapolations to the physical pion mass and to the continuum limit the vector and scalar form factors are determined in the whole kinematical region from q2 = 0 up to [see formula in PDF] accessible in the experiments, obtaining a good overall agreement with experiments, except in the region at high values of q2 where some deviations are visible.

scholarly journals Nucleon form factors on a large volume lattice near the physical point in 2+1 flavor QCD

2018 ◽  
Vol 98 (7) ◽  
Author(s):  
Ken-Ichi Ishikawa ◽  
Yoshinobu Kuramashi ◽  
Shoichi Sasaki ◽  
Natsuki Tsukamoto ◽  
Akira Ukawa ◽  
...  
Keyword(s):  
Large Volume ◽  
Form Factors ◽  
Physical Point ◽  
Nucleon Form Factors

scholarly journals Nucleon form factors near the physical point in 2+1 flavor QCD

2017 ◽  
Author(s):  
Yoshinobu Kuramashi ◽  
K.-I. Ishikawa ◽  
Shoichi Sasaki ◽  
Takeshi Yamazaki ◽  
N. Tsukamoto ◽  
...  
Keyword(s):  
Form Factors ◽  
Physical Point ◽  
Nucleon Form Factors

scholarly journals Nucleon form factors from Nf=2+1+1 twisted mass fermions at the physical point

2019 ◽  
Author(s):  
Martha Constantinou ◽  
Constantia Alexandrou ◽  
Simone Bacchio ◽  
Kyriakos Hadjiyiannakou ◽  
Giannis Koutsou ◽  
...  
Keyword(s):  
Form Factors ◽  
Physical Point ◽  
Twisted Mass ◽  
Nucleon Form Factors

NUCLEON STRUCTURE AT JEFFERSON LAB: FROM TWO DIMENSIONS TO THREE DIMENSIONS

2009 ◽  
Vol 18 (10) ◽  
pp. 2181-2186
Author(s):  
MICHEL GUIDAL
Keyword(s):  
Phase Space ◽  
Degrees Of Freedom ◽  
Form Factors ◽  
Two Dimensions ◽  
Three Dimensions ◽  
Nucleon Structure ◽  
Parton Distributions ◽  
Jefferson Lab ◽  
Generalized Parton Distributions ◽  
Nucleon Form Factors

We review very briefly a few recent highlight results from Jefferson Lab concerning nucleon Form Factors and Generalized Parton Distributions for which data with unprecedented precision and phase space coverage have be obtained these past few years. Along with new theoretical developements, these data allow to make some nucleon imaging in terms of partonic degrees of freedom in both momentum and space dimensions.

scholarly journals Electromagnetic and axial-vector form factors of the quarks and nucleon

2017 ◽  
Vol 32 (31) ◽  
pp. 1750185 ◽  
Author(s):  
Harleen Dahiya ◽  
Monika Randhawa
Keyword(s):  
Chiral Symmetry Breaking ◽  
Axial Vector ◽  
Dynamical Behavior ◽  
Form Factors ◽  
Constituent Quark Model ◽  
Strong Interactions ◽  
Vector Form ◽  
Static Properties ◽  
Nucleon Form Factors ◽  
Dipole Form

In light of the improved precision of the experimental measurements and enormous theoretical progress, the nucleon form factors have been evaluated with an aim to understand how the static properties and dynamical behavior of nucleons emerge from the theory of strong interactions between quarks. We have analyzed the vector and axial-vector nucleon form factors ([Formula: see text] and [Formula: see text]) using the spin observables in the chiral constituent quark model ([Formula: see text]CQM) which has made a significant contribution to the unraveling of the internal structure of the nucleon in the nonperturbative regime. We have also presented a comprehensive analysis of the flavor decomposition of the form factors ([Formula: see text], [Formula: see text] and [Formula: see text] for [Formula: see text]) within the framework of [Formula: see text]CQM with emphasis on the extraction of the strangeness form factors which are fundamental to determine the spin structure and test the chiral symmetry breaking effects in the nucleon. The [Formula: see text] dependence of the vector and axial-vector form factors of the nucleon has been studied using the conventional dipole form of parametrization. The results are in agreement with the available experimental data.

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