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 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

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 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 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

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 HVP contributions to the muon (g−2) including QED corrections with twisted-mass fermions

2018 ◽  
Vol 175 ◽  
pp. 06006
Author(s):  
Davide Giusti ◽  
Vittorio Lubicz ◽  
Guido Martinelli ◽  
Francesco Sanfilippo ◽  
Silvano Simula
Keyword(s):  
Lattice Spacing ◽  
Pion Mass ◽  
Charm Quark ◽  
Leading Order ◽  
Lattice Calculation ◽  
Charm Quarks ◽  
Quark Masses ◽  
Mass Collaboration ◽  
Twisted Mass ◽  
The Continuum

We present a lattice calculation of the Hadronic Vacuum Polarization (HVP) contribution of the strange and charm quarks to the anomalous magnetic moment of the muon including leading-order electromagnetic (e.m.) corrections. We employ the gauge configurations generated by the European Twisted Mass Collaboration (ETMC) with Nf = 2+1 + 1 dynamical quarks at three values of the lattice spacing (a ≃ 0.062,0.082,0.089 fm) with pion masses in the range Mπ ≃ 210 - 450 MeV. The strange and charm quark masses are tuned at their physical values. Neglecting discon-nected diagrams and after the extrapolations to the physical pion mass and to the continuum limit we obtain: [see formula in PDF] and [see formula in PDF] for the strange and charm contributions, respectively.!

scholarly journals Electromagnetic transition form factors of baryons in a relativistic Faddeev approach

2018 ◽  
Vol 181 ◽  
pp. 01013 ◽  
Author(s):  
Reinhard Alkofer ◽  
Christian S. Fischer ◽  
Hèlios Sanchis-Alepuz
Keyword(s):  
Ground State ◽  
Bound States ◽  
Body Wave ◽  
Form Factors ◽  
Wave Functions ◽  
Electromagnetic Form Factors ◽  
Transition Form ◽  
Electromagnetic Transition ◽  
Three Body ◽  
Gluon Interaction

The covariant Faddeev approach which describes baryons as relativistic three-quark bound states and is based on the Dyson-Schwinger and Bethe-Salpeter equations of QCD is briefly reviewed. All elements, including especially the baryons’ three-body-wave-functions, the quark propagators and the dressed quark-photon vertex, are calculated from a well-established approximation for the quark-gluon interaction. Selected previous results of this approach for the spectrum and elastic electromagnetic form factors of ground-state baryons and resonances are reported. The main focus of this talk is a presentation and discussion of results from a recent investigation of the electromagnetic transition form factors between ground-state octet and decuplet baryons as well as the octet-only Σ0 to Λ transition.

scholarly journals Nucleon electromagnetic form factors using lattice simulations at the physical point

2017 ◽  
Vol 96 (3) ◽  
Author(s):  
C. Alexandrou ◽  
M. Constantinou ◽  
K. Hadjiyiannakou ◽  
K. Jansen ◽  
Ch. Kallidonis ◽  
...  
Keyword(s):  
Form Factors ◽  
Electromagnetic Form Factors ◽  
Physical Point
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