English
Related papers

Related papers: Pion form factor with twisted mass QCD

200 papers

We report on the lowest moment of parton distribution functions and generalized form factors for the pion at several values of the momentum transfer. Calculations are performed for N_f=2 flavors of O(a) improved Wilson fermions with pion…

High Energy Physics - Lattice · Physics 2013-12-02 G. Bali , S. Collins , B. Glässle , M. Göckeler , N. Javadi-Motaghi , J. Najjar , W. Söldner , A. Sternbeck

The holographic QCD prediction for the pion distribution amplitude (DA) $\phi_{hol}(u)$ is used to compute the pion spacelike electromagnetic form factor $F_{\pi}(Q^2)$ within the QCD light-cone sum rule method. In calculations the pion's…

High Energy Physics - Phenomenology · Physics 2008-11-26 S. S. Agaev , M. A. Gomshi Nobary

The electromagnetic pion form factor, $F_\pi(q^2)$, is calculated for spacelike-$q^2$ in impulse approximation using a confining quark propagator, $S$, and a dressed quark-photon vertex, $\Gamma_\mu$, obtained from realistic,…

High Energy Physics - Phenomenology · Physics 2010-03-04 Craig D. Roberts

Moments of generalised parton distributions can be related to off-forward matrix elements of local operators. We calculate a few of the leading twist matrix elements for the pion on the lattice. The simulations are performed using two…

High Energy Physics - Lattice · Physics 2008-11-26 D. Brömmel , M. Diehl , M. Göckeler , Ph. Hägler , R. Horsley , D. Pleiter , P. E. L. Rakow , A. Schäfer , G. Schierholz , J. M. Zanotti

We calculate the scalar form factor of the pion using two dynamical flavors of non-perturbatively $\mathcal{O}(a)$-improved Wilson fermions, including both the connected and the disconnected contribution to the relevant correlation…

High Energy Physics - Lattice · Physics 2014-05-14 Vera Gülpers , Georg von Hippel , Hartmut Wittig

We present a status report of our calculation of the electromagnetic form factor of the pion on the PACS-CS gauge field configurations generated using Iwasaki gauge action and Wilson-clover quark action for 2 + 1 flavors of light dynamical…

High Energy Physics - Lattice · Physics 2011-02-01 CS Collaboration

We point out a caveat in the proof for automatic O(a) improvement in twisted mass lattice QCD at maximal twist angle. With the definition for the twist angle previously given by Frezzotti and Rossi, automatic O(a) improvement can fail…

High Energy Physics - Lattice · Physics 2009-11-10 Sinya Aoki , Oliver Baer

We present a quantitative analysis of the electromagnetic pion form factor in the light-cone sum rule approach, including radiative corrections and higher-twist effects. The comparison to the existing data favors the asymptotic profile of…

High Energy Physics - Phenomenology · Physics 2011-05-05 V. M. Braun , A. Khodjamirian , M. Maul

In this work, we employ a dispersion relation that allows to recover the electromagnetic form factor of the pion from its modulus along the unitarity cut. Unlike the standard dispersive approach, this method extends in a straightforward…

High Energy Physics - Phenomenology · Physics 2024-10-24 Pablo Sanchez-Puertas , Enrique Ruiz Arriola

We calculate the s-wave pion-pion scattering length in the isospin I=2 channel in lattice QCD for pion masses ranging from 270 Mev to 485 Mev using two flavors of maximally twisted mass fermions at a lattice spacing of 0.086 fm.…

High Energy Physics - Lattice · Physics 2010-11-26 Xu Feng , Karl Jansen , Dru B. Renner

We present results of a calculation of the electromagnetic pion form factor within the framework of QCD Sum Rules with nonlocal condensates, using a perturbative spectral density which includes $O(\alpha_s)$ contributions.

High Energy Physics - Phenomenology · Physics 2014-11-18 Alexander P. Bakulev , A. V. Pimikov , N. G. Stefanis

We calculate the QCD moments of the pion structure function using Drell-Yan data on the quark distributions in the pion and a phenomenological model for the resonance region. The extracted higher twist corrections are found to be larger…

High Energy Physics - Phenomenology · Physics 2014-11-17 W. Melnitchouk

We present the current status of our lattice calculation of the electromagnetic form factor of the pion with two flavours of non-perturbatively O(a)-improved Wilson fermions. Using twisted boundary conditions and stochastic sources we…

High Energy Physics - Lattice · Physics 2013-01-17 Bastian B. Brandt , Andreas Juttner , Hartmut Wittig

In the framework of Wilson Chiral Perturbation Theory, we study the effect induced by a twisted Wilson term, as it appears in Twisted Mass QCD (with 2 degenerate quarks). In particular we consider the vacuum orientation and the pion masses.…

High Energy Physics - Lattice · Physics 2009-11-10 Luigi Scorzato

We propose a simple method to calculate the pion form factor at not very large momentum transfers, which combines the technique of the QCD sum rules with the description of the pion in terms of the set of wave functions of increasing twist.…

High Energy Physics - Phenomenology · Physics 2009-10-28 V. M. Braun , I. Halperin

We report on our computation of the pion transition form factor ${\cal F}_{P\rightarrow \gamma^*\gamma^*}$ from twisted mass lattice QCD in order to determine the numerically dominant light pseudoscalar pole contribution in the hadronic…

Based on the light-cone (LC) framework and the $k_T$ factorization formalism, the transverse momentum effects and the different helicity components' contributions to the pion form factor $F_{\pi}(Q^2)$ are recalculated. In particular, the…

High Energy Physics - Phenomenology · Physics 2009-11-11 Xing-Gang Wu , Tao Huang

We calculate the electromagnetic pion form factor at intermediate space-like momentum transfer from the QCD sum rule for the correlation function of two {\it pseudoscalar } interpolating fields and the electromagnetic current. This…

High Energy Physics - Phenomenology · Physics 2009-10-28 Hilmar Forkel , Marina Nielsen

We compute the pion electromagnetic form factor in a hybrid calculation with domain wall valence quarks and improved staggered (asqtad) sea quarks. This method can easily be extended to rho-to-gamma-pi transition form factors.

High Energy Physics - Lattice · Physics 2014-11-17 LHP Collaboration , George T. Fleming , Frederic D. R. Bonnet , Robert G. Edwards , Randy Lewis , David G. Richards

We present a first scaling test of twisted mass QCD with pure Wilson quarks for a twisting angle of pi/2. We have computed the vector meson mass and the pseudoscalar decay constant for different values of beta at fixed value of r_0 m_PS.…

High Energy Physics - Lattice · Physics 2009-11-10 Karl Jansen , Andrea Shindler , Carsten Urbach , Ines Wetzorke