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Related papers: Pion form factor with chirally improved fermions

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We have calculated the 3-point correlation function for the electromagnetic interaction of the pion in an ensembles of instantons and anti-instantons, modelling the QCD vacuum. The results are well described by a pion pole and the pion…

High Energy Physics - Phenomenology · Physics 2014-11-17 Andree Blotz , Edward Shuryak

The electromagnetic form factors provide important hints for the internal structure of the nucleon and continue to be of major interest for experimentalists. For an intermediate range of momentum transfers the form factors can be calculated…

We present new lattice results of the K -> pion semileptonic form factors obtained from simulations with two flavors of dynamical twisted-mass fermions, using pion masses as light as 260 MeV. Our main result is f+(0) = 0.9560 (84), which,…

High Energy Physics - Lattice · Physics 2019-08-13 V. Lubicz , F. Mescia , S. Simula , C. Tarantino

We present a calculation of pion electromagnetic and scalar form factors in two-flavor QCD with the non-perturbatively O(a)-improved Wilson fermion. Chiral extrapolation of the corresponding charge radius is discussed based on the chiral…

The renormalizable Abelian quantum field theory model of Kroll, Lee, and Zumino is used to compute the one-loop vertex corrections to the tree-level, Vector Meson Dominance (VMD) pion form factor. These corrections, together with the known…

High Energy Physics - Phenomenology · Physics 2008-11-26 Cesareo A. Dominguez , Juan I. Jottar , Marcelo Loewe , Bernard Willers

Based on the field-theory-inspired approach, a new expression for the pion form factor F_pi is proposed. It takes into account the pseudoscalar meson loops $\pi^+\pi^-$ and $K\bar K$ and the mixing of $\rho(770)$ with heavier $\rho(1450)$…

High Energy Physics - Phenomenology · Physics 2015-06-11 N. N. Achasov , A. A. Kozhevnikov

We calculate the electromagnetic form factor of the pion in lattice gauge theory. The non-perturbatively improved Sheikoleslami-Wohlert lattice action is used together with the O(a) improved current. The form factor is compared to results…

High Energy Physics - Lattice · Physics 2009-11-10 J. van der Heide , J. H. Koch , E. Laermann , M. Lutterot

We evaluate the vector and scalar form factor of the pion in the presence of virtual photons at next-to-leading order in two-flavor chiral perturbation theory. We also consider the scalar and tensor pion form factors of the energy-momentum…

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

The pion electromagnetic form factor has been calculated for the first time from the solutions of the Bethe-Salpeter equation, obtained directly in Minkowski space by using the Nakanishi integral representation of the Bethe-Salpeter…

High Energy Physics - Phenomenology · Physics 2021-08-18 Emanuel Ydrefors , Wayne de Paula , Jorge H Alvarenga Nogueira , Tobias Frederico , Giovanni Salmé

We study isospin-1 P-wave $\pi\pi$ scattering in lattice QCD with two flavours of O($a$) improved Wilson fermions. For pion masses ranging from $m_\pi=265$ MeV to $m_\pi=437$ MeV, we determine the energy spectrum in the centre-of-mass frame…

High Energy Physics - Lattice · Physics 2020-03-17 Felix Erben , Jeremy R. Green , Daniel Mohler , Hartmut Wittig

Lattice QCD can provide a direct determination of meson electromagnetic form factors, making predictions for upcoming experiments at Jefferson Lab. The form factors are a reflection of the bound-state nature of the meson and so these…

High Energy Physics - Lattice · Physics 2019-02-12 C. T. H. Davies , J. Koponen , G. P. Lepage , A. T. Lytle , A. C. Zimermmane-Santos

We present new high-statistics results for nucleon form factors at pion masses of approximately 290, 350, 500, and 600 MeV using a mixed action of domain wall valence quarks on an improved staggered sea. We perform chiral fits to both…

Form factors for pions interactions with constituent quarks are investigated as the leading effective couplings obtained from a one loop background field method applied to a global color model. Two pion field definitions are considered and…

High Energy Physics - Phenomenology · Physics 2023-03-27 Fabio L. Braghin

We present a systematic lattice calculation of the vector and axial vector form factors $V$ and $A_i~(i=0,1,2)$ for the $D_s \to \phi \ell \nu_\ell$ semileptonic decay using (2+1)-flavor Wilson-clover fermion configurations generated by the…

High Energy Physics - Lattice · Physics 2026-01-27 Gaofeng Fan , Yu Meng , Chuan Liu , Zhaofeng Liu , Tinghong Shen , Ting-Xiao Wang , Ke-Long Zhang , Lei Zhang

The gravitational form factor of the pion is evaluated in two chiral quark models and confronted to the recent full-QCD lattice data. We find good agreement for the case of the Spectral Quark Model, which builds in the vector-meson…

High Energy Physics - Phenomenology · Physics 2008-12-18 Wojciech Broniowski , Enrique Ruiz Arriola

The suggestion of momentum dependence in the amplitude for rho-omega mixing has generated concern over related implications for vector meson dominance and the photon-rho coupling. We discuss two established representations of vector meson…

High Energy Physics - Phenomenology · Physics 2008-11-26 H. B. O'Connell , B. C. Pearce , A. W. Thomas , A. G. Williams

The pion form factor is computed using quenched twisted mass QCD and the GMRES-DR matrix inverter. The momentum averaging procedure of Frezzotti and Rossi is used to remove leading lattice spacing artifacts, and numerical results for the…

High Energy Physics - Lattice · Physics 2009-11-10 Abdou M. Abdel-Rehim , Randy Lewis

The extrapolation of nucleon magnetic form factors calculated within lattice QCD is investigated within a framework based upon heavy baryon chiral effective-field theory. All one-loop graphs are considered at arbitrary momentum transfer and…

High Energy Physics - Phenomenology · Physics 2008-11-26 P. Wang , D. B. Leinweber , A. W. Thomas , R. D. Young

We calculate pion mass, pion decay constant, PCAC quark mass and nucleon mass in two flavour lattice QCD with unimproved Wilson fermion and gauge actions. Simulations are performed using DD-HMC algorithm at two lattice spacings and two…

High Energy Physics - Lattice · Physics 2015-06-12 Abhishek Chowdhury , Asit K. De , Sangita De Sarkar , A. Harindranath , Jyotirmoy Maiti , Santanu Mondal , Anwesa Sarkar

Separated longitudinal and transverse structure functions for the reaction 1H(e,eprime pi+)n were measured in the momentum transfer region Q2=0.6-1.6 (GeV/c)**2 at a value of the invariant mass W=1.95 GeV. New values for the pion charge…

Nuclear Experiment · Physics 2009-04-15 J. Volmer