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The two-pion contribution from low energies to the muon magnetic moment anomaly, although small, has a large relative uncertainty since in this region the experimental data on the cross sections are neither sufficient nor precise enough. It…

High Energy Physics - Phenomenology · Physics 2014-02-24 B. Ananthanarayan , Irinel Caprini , Diganta Das , I. Sentitemsu Imsong

We discuss the nonleading, ``soft" contribution to the pion form factor at intermediate momentum transfer within operator product expansion approach. We argue, that the corresponding contribution can temporarily {\bf simulate} the leading…

High Energy Physics - Phenomenology · Physics 2009-09-25 A. Zhitnitsky

Motivated by the discrepancies noted recently between the theoretical calculations of the electromagnetic $\omega\pi$ form factor and certain experimental data, we investigate this form factor using analyticity and unitarity in a framework…

High Energy Physics - Phenomenology · Physics 2014-12-19 B. Ananthanarayan , I. Caprini , B. Kubis

We present an investigation of the electromagnetic pion form factor, $F_\pi(Q^2)$, at small values of the four-momentum transfer $Q^2$ ($\lesssim 0.25$ GeV$^2$), based on the gauge configurations generated by European Twisted Mass…

We present a lattice calculation of the vector form factor of the pion for two flavours of non-perturbatively O(a) improved Wilson fermions. For the measurements we utilise the CLS ensembles which include various lattice spacings and pion…

High Energy Physics - Lattice · Physics 2011-09-02 Bastian B. Brandt , Andreas Juttner , Hartmut Wittig

The pion electromagnetic form factor is calculated within the QCD light-cone sum rule method and using a renormalon model for the higher twist distribution amplitudes (DAs). The theoretical predictions are compared with the experimental…

High Energy Physics - Phenomenology · Physics 2009-11-11 S. S. Agaev

A continuum approach to the kaon and pion bound-state problems is used to reveal their electromagnetic structure. For both systems, when used with parton distribution amplitudes appropriate to the scale of the experiment, Standard Model…

Nuclear Theory · Physics 2017-09-06 Fei Gao , Lei Chang , Yu-Xin Liu , Craig D. Roberts , Peter C. Tandy

We comment on the results of a complete leading-twist next-to-leading order QCD analysis of the spacelike pion electromagnetic form factor at large-momentum transfer Q. For the asymptotic distribution amplitude, we have examined the…

High Energy Physics - Phenomenology · Physics 2009-08-25 B. Melic , B. Nizic , K. Passek

We present a formula that allows one to calculate the pion form factor in the timelike region 2mpi <= sqrt{s} <= 4mpi in lattice QCD. The form factor quantifies the contribution of two-pion states to the vacuum polarization. It must be…

High Energy Physics - Lattice · Physics 2012-04-04 Harvey B. Meyer

A novel method is employed to compute the pion electromagnetic form factor, F_\pi(Q^2), on the entire domain of spacelike momentum transfer using the Dyson-Schwinger equation (DSE) framework in quantum chromodynamics (QCD). The DSE…

Nuclear Theory · Physics 2015-06-16 L. Chang , I. C. Cloet , C. D. Roberts , S. M. Schmidt , P. C. Tandy

We suggest to probe the pion light-cone distribution amplitude, applying a dispersion relation for the pion electromagnetic form factor. Instead of the standard dispersion relation, we use the equation between the spacelike form factor…

High Energy Physics - Phenomenology · Physics 2020-11-04 Shan Cheng , Alexander Khodjamirian , Aleksey V. Rusov

We perform a stability analysis of a recently proposed sum rule for pion Compton scattering at fixed angle and moderate Mandelstam invariants. The sum rule is found to be sensitive to the parameter $\lambda^2$, the contour radius of a…

High Energy Physics - Phenomenology · Physics 2009-10-22 Claudio Coriano' , Hsiang-nan Li

We present a determination of the pion charge radius from high precision data on the pion vector form factor from both timelike and spacelike regions, using a novel formalism based on analyticity and unitarity. At low energies, instead of…

High Energy Physics - Phenomenology · Physics 2017-10-04 B. Ananthanarayan , Irinel Caprini , Diganta Das

We extend recently developed methods used for determining the electromagnetic charge radius and $a_\mu^{\pi\pi}$ to obtain a determination of the electromagnetic form factor of the pion, $F_\pi^V(t)$, in several significant kinematical…

High Energy Physics - Phenomenology · Physics 2019-01-02 B. Ananthanarayan , Irinel Caprini , Diganta Das

In this work, we investigate the time-like pion form factor from lattice QCD in the isosymmetric limit, a quantity that plays an important role in understanding hadron physics with substantial phenomenological applications. This observable…

High Energy Physics - Lattice · Physics 2026-03-05 Gabriele Morandi , Mattia Bruno , Francesca Argia Bresciani , Christoph Lehner , Julian Parrino

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

The pion electromagnetic form factor with leading and next-to-leading twist corrections are studied in the framework of pQCD approach. We find that, at small momentum transfer regions, Sudakov effects cannot provide a strong enough…

High Energy Physics - Phenomenology · Physics 2007-05-23 Zheng-Tao Wei , Mao-Zhi Yang

We present a calculation of the electromagnetic form factor of the pion in $N_f=2+1$ flavor lattice QCD. Calculations are made on the PACS-CS gauge field configurations generated using Iwasaki gauge action and Wilson-clover quark action on…

High Energy Physics - Lattice · Physics 2011-05-09 Oanh Hoang Nguyen , Ken-Ichi Ishikawa , Akira Ukawa , Naoya Ukita

We employ a dispersion relation that allows to recover the phase of the electromagnetic form factor of the pion from its absolute value above threshold. Compared to alternative approaches building on the phase, this approach builds on…

High Energy Physics - Phenomenology · Physics 2024-07-29 Enrique Ruiz Arriola , Pablo Sanchez-Puertas

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