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Related papers: Pion quark structure in QCD

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The nonperturbative, Dyson-Schwinger equation approach to solving QCD provides a straightforward, microscopic description of dynamical chiral symmetry breaking and confinement. It is an ideal tool for the study of pion observables. This is…

High Energy Physics - Phenomenology · Physics 2009-10-28 Craig D. Roberts

We compare two approaches to the description of pion Compton scattering at moderate momentum transfer, one being based on local duality QCD sum rules for the invariant amplitudes of the process, which have been derived recently, and the…

High Energy Physics - Phenomenology · Physics 2010-11-01 Claudio Coriano' , Hsiang-nan Li

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

In this lattice QCD study we evaluate the nucleon spin decomposition to quarks and gluons contributions. We employ one gauge ensemble of maximally twisted mass fermions with two degenerate light quarks tuned to approximately reproduce the…

In this article we address the physical basis of the deviation of hadron shapes from spherical symmetry (non-spherical amplitudes) with focus on the nucleon and $\Delta$. An overview of both the experimental methods and results and the…

High Energy Physics - Phenomenology · Physics 2009-01-06 A. M. Bernstein , C. N. Papanicolas

We extract pion parton distribution functions (PDFs) in a Monte Carlo global QCD analysis of experimental data together with reduced Ioffe time pseudo-distributions and matrix elements of current-current correlators generated from lattice…

High Energy Physics - Phenomenology · Physics 2022-07-13 P. C. Barry , C. Egerer , J. Karpie , W. Melnitchouk , C. Monahan , K. Orginos , Jian-Wei Qiu , D. Richards , N. Sato , R. S. Sufian , S. Zafeiropoulos

We recalculated pion virtual Compton scattering in perturbative QCD in this paper. Our calculation avoids some deficiencies in existing literatures, and treats real Compton scattering as a limit case in which the mass of the virtual photon…

High Energy Physics - Phenomenology · Physics 2015-06-25 Ding-fang Zeng , Bo-qiang Ma

We present a lattice QCD determination of the distribution amplitude (DA) of the pion and the first few Mellin moments from an analysis of the quasi-DA matrix element within the leading-twist framework. We perform our study on a HISQ…

High Energy Physics - Lattice · Physics 2022-10-21 Xiang Gao , Andrew D. Hanlon , Nikhil Karthik , Swagato Mukherjee , Peter Petreczky , Philipp Scior , Sergey Syritsyn , Yong Zhao

The structure of the 1/Nc expansion for the baryon distribution amplitude in QCD is tested using quark models. Earlier conjectures about this structure based on the evolution equation and on the soft-pion theorem are confirmed by the model…

High Energy Physics - Phenomenology · Physics 2007-05-23 P. V. Pobylitsa

We use a chiral model for pion interactions, in the inverse amplitude formalism, to perform a simultaneous analysis of lattice QCD results for pion-pion scattering in all three isospin channels. The input is the finite-volume two-pion…

High Energy Physics - Lattice · Physics 2020-01-01 Maxim Mai , Chris Culver , Andrei Alexandru , Michael Döring , Frank X. Lee

We discuss the pion and kaon distribution amplitudes up to twist-3 in the context of the random instanton vacuum (RIV). We construct explicitly the pertinent quasi-pion and quasi-kaon distributions in the RIV, and analyze them in leading…

High Energy Physics - Phenomenology · Physics 2022-01-12 Arthur Kock , Ismail Zahed

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

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 here an extension of our model for the pion, which we used previously to calculate its diagonal structure function, to the off-forward case. The imaginary part of the off-forward gamma^* pi -> gamma^* pi scattering amplitude is…

High Energy Physics - Phenomenology · Physics 2007-05-23 J. P. Lansberg , F. Bissey , J. R. Cudell , J. Cugnon , P. Stassart

We evaluate the pion_0 into two gammas decay amplitude by an effective action derived from QCD in the quark composites approach, getting the standard value. We also verify that our effective action correctly reproduces the chiral anomaly.

High Energy Physics - Lattice · Physics 2007-05-23 Sergio Caracciolo , Fabrizio Palumbo

We consider the pion-photon transition form factor at low to intermediate spacelike momenta within the theoretical framework of light-cone sum rules. We derive predictions which take into account all currently known contributions stemming…

High Energy Physics - Phenomenology · Physics 2017-03-24 S. V. Mikhailov , A. V. Pimikov , N. G. Stefanis

In this work, we investigate the gluon distribution functions for the pion and kaon, in addition to the improved result of the valence-quark ones, in the gauge-invariant nonlocal chiral-quark model (NL$\chi$QM), in which the momentum…

High Energy Physics - Phenomenology · Physics 2023-02-14 Parada T. P. Hutauruk , Seung-il Nam

We present preliminary study of parton distribution inside the pion using mixed action approach with HYP smeared valence clover quarks on HISQ sea within the framework of Large Momentum Effective Theory. We use 2+1 flavor $48^3 \times 64$…

The I=2 pipi scattering length is calculated in fully-dynamical lattice QCD with domain-wall valence quarks on the asqtad-improved coarse MILC configurations (with fourth-rooted staggered sea quarks) at four light-quark masses. Two- and…

High Energy Physics - Lattice · Physics 2008-11-26 Silas R. Beane , Thomas C. Luu , Kostas Orginos , Assumpta Parreno , Martin J. Savage , Aaron Torok , Andre Walker-Loud

We present the results on the relativistic six-pion scattering amplitude at low energy, calculated at $\mathcal{O}(p^4)$ within the framework of the massive $\text{O}(N)$ nonlinear sigma model extended to the next-to-leading order in the…

High Energy Physics - Phenomenology · Physics 2022-04-04 Tomáš Husek
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