scholarly journals Nucleon axial form factors using Nf=2 twisted mass fermions with a physical value of the pion mass

2017 ◽  
Vol 96 (5) ◽  
Author(s):  
C. Alexandrou ◽  
M. Constantinou ◽  
K. Hadjiyiannakou ◽  
K. Jansen ◽  
C. Kallidonis ◽  
...  
Keyword(s):  
Pion Mass ◽  
Form Factors ◽  
Twisted Mass ◽  
Axial Form

scholarly journals Connected and disconnected contributions to nucleon axial form factors using Nf = 2 twisted mass fermions at the physical point

2018 ◽  
Vol 175 ◽  
pp. 06003 ◽  
Author(s):  
Constantia Alexandrou ◽  
Martha Constantinou ◽  
Kyriakos Hadjiyiannakou ◽  
Karl Jansen ◽  
Christos Kallidonis ◽  
...  
Keyword(s):  
Ground State ◽  
Pion Mass ◽  
Charm Quark ◽  
Form Factors ◽  
Physical Point ◽  
Twisted Mass ◽  
Axial Form ◽  
Wilson Fermions ◽  
Quark Loops

We present results on the isovector and isoscalar nucleon axial form factors including disconnected contributions, using an ensemble of Nf = 2 twisted mass cloverimproved Wilson fermions simulated with approximately the physical value of the pion mass. The light disconnected quark loops are computed using exact deflation, while the strange and the charm quark loops are evaluated using the truncated solver method. Techniques such as the summation and the two-state fits have been employed to access ground-state dominance.

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.

Nucleon electromagnetic and axial form factors with N$_\textrm{f}=2$ twisted mass fermions at the physical point

2016 ◽  
Author(s):  
Giannis Koutsou ◽  
Constantia Alexandrou ◽  
Martha Constantinou ◽  
Kyriakos Hadjiyiannakou ◽  
Karl Jansen ◽  
...  
Keyword(s):  
Form Factors ◽  
Physical Point ◽  
Twisted Mass ◽  
Axial Form

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 THE NUCLEON'S MIRROR IMAGE: REVEALING THE STRANGE AND UNEXPECTED

2003 ◽  
Vol 18 (02n06) ◽  
pp. 75-84 ◽  
Author(s):  
R. D. MCKEOWN
Keyword(s):  
Form Factor ◽  
Electron Scattering ◽  
Strange Quark ◽  
Form Factors ◽  
Mirror Image ◽  
Vector Form ◽  
Electromagnetic Structure ◽  
Extensive Program ◽  
Axial Form ◽  
Insight Into

An extensive program of parity-violating electron scattering experiments is providing new insight into the structure of the nucleon. Measurement of the vector form factors enables a definitive study of potential strange quark-antiquark contributions to the nucleon's electromagnetic structure, including the magnetic moment and charge distribution. Recent experimental results have already indicated that effects of strangeness are much smaller than theoretically expected. In addition, the neutral axial form factor appears to display substantial corrections as one might expect from an anapole effect.

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