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In this presentation, we briefly review recent investigations on pion and kaon structures from the instanton vacuum. Starting from the low-energy QCD partition function, we have computed the Gasser-Leutwyler low-energy constants,…

High Energy Physics - Phenomenology · Physics 2015-05-13 Hyun-Chul Kim , Seung-il Nam , Hyun-Ah Choi

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 present a first Wilson twisted mass fermion calculation of the matrix element between pion states of the twist-2 operator, which is related to the the lowest moment < x > of the valence quark parton distribution function in a pion. Using…

High Energy Physics - Lattice · Physics 2009-11-11 S. Capitani , K. Jansen , M. Papinutto , A. Shindler , C. Urbach , I. Wetzorke

We derive an explicit and model-independent representation for the skewed quark distribution of the pion in the limit of large momentum transfer. Our result is expressed in terms of the conventional pion distribution amplitudes and complies…

High Energy Physics - Phenomenology · Physics 2014-11-17 C. Vogt

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 $48^3 \times 64$…

Pion valence, glue and sea distributions are calculated using a continuum approach to the two valence-body bound-state problem. Since the framework is symmetry preserving, physical features of the distributions are properly expressed. The…

Nuclear Theory · Physics 2020-03-18 Minghui Ding , Khepani Raya , Daniele Binosi , Lei Chang , C. D. Roberts , S. M. Schmidt

Instanton effects can give large contribution to strong interacting processes, especially at the energy scale where perturbative QCD is no longer valid. However instanton contribution to the gluon contribution in constituent quark and…

High Energy Physics - Phenomenology · Physics 2018-08-01 Baiyang Zhang , Nikolai Kochelev , Hee-Jung Lee , Pengming Zhang

It has been suggested that parton distributions in coordinate space, so called Ioffe-time distributions, provide a more natural object for non-perturbative methods compared to the usual momentum distributions. In this paper we argue that…

High Energy Physics - Phenomenology · Physics 2009-10-28 L. Mankiewicz , T. Weigl

We report an exploratory study of the current-current matrix elements that are relevant to the extraction of moments of the pion light-cone distribution amplitude, employing the method of introducing a valence relativistic heavy quark. The…

High Energy Physics - Lattice · Physics 2018-10-30 William Detmold , Issaku Kanamori , C. -J. David Lin , Santanu Mondal , Yong Zhao

We calculate the leading twist valence quark distribution in the pion in the franework of QCD sum rules with nonlocal condensates. Particular attention has been paid to the correct account of the bilocal power corrections.

High Energy Physics - Phenomenology · Physics 2007-05-23 A. V. Belitsky

Generalized parton distributions provide a unified parameterization of hadron structure and allow one to combine information from many different observables. Lattice QCD calculations already provide important input to determine these…

High Energy Physics - Phenomenology · Physics 2010-04-05 M. Diehl , A. Manashov , A. Schafer

The contribution of the quark-quark and quark-gluon interaction induced by instantons to the valence quark and proton spin-dependent structure functions $g_1(x,Q^2)$ is estimated within the instanton liquid model for QCD vacuum. It is…

High Energy Physics - Phenomenology · Physics 2009-10-30 N. I. Kochelev

We investigate the internal structure of the ground ($1S$) and the first two radially excited ($2S,3S$) states of the pion within the light-front quark model. The valence Fock sector is described using pure harmonic-oscillator eigenstates…

High Energy Physics - Phenomenology · Physics 2026-01-13 Ashutosh Dwibedi , Satyajit Puhan , Sabyasachi Ghosh , Harleen Dahiya

In this work, we report a lattice calculation of $x$-dependent valence pion generalized parton distributions (GPDs) at zero skewness with multiple values of the momentum transfer $-t$. The calculations are based on an $N_f=2+1$ gauge…

High Energy Physics - Lattice · Physics 2025-02-14 Heng-Tong Ding , Xiang Gao , Swagato Mukherjee , Peter Petreczky , Qi Shi , Sergey Syritsyn , Yong Zhao

We present a state-of-the-art calculation of the unpolarized pion valence-quark distribution in the framework of large-momentum effective theory (LaMET) with improved handling of systematic errors as well as two-loop perturbative matching.…

High Energy Physics - Lattice · Physics 2024-04-24 Jack Holligan , Huey-Wen Lin

We study the effects of instantons on the charged pion electro-magnetic formfactor at intermediate momenta. In the Single Instanton Approximation (SIA), we predict the pion formfactor in the kinematic region Q^2=2-15 GeV^2. By developing…

High Energy Physics - Phenomenology · Physics 2009-11-07 P. Faccioli , A. Schwenk , E. V. Shuryak

We calculate the two-pion light-cone distribution amplitudes in the effective low-energy theory based on the instanton vacuum. These generalized distribution amplitudes describe the soft (non-perturbative) part of the process…

High Energy Physics - Phenomenology · Physics 2009-12-30 M. V. Polyakov , C. Weiss

We introduce gauge-invariant quark and gluon angular momentum distributions after making a generalization of the angular momentum density operators. From the quark angular momentum distribution, we define the gauge-invariant and…

High Energy Physics - Phenomenology · Physics 2009-10-31 Pervez Hoodbhoy , Xiangdong Ji , Wei Lu

We compute the pion quark Generalised Parton Distribution H and quark Double Distributions in a coupled Bethe-Salpeter and Dyson-Schwinger approach in terms of quark flavors or isospin states. We use analytic expressions inspired by the…

High Energy Physics - Phenomenology · Physics 2015-07-22 C. Mezrag

The pion form factors of the QCD energy-momentum tensor (EMT) are studied in the instanton liquid model (ILM) of the QCD vacuum. In this approach the breaking of conformal symmetry is encoded in the form of stronger-than-Poisson…

High Energy Physics - Phenomenology · Physics 2024-10-16 Wei-Yang Liu , Edward Shuryak , Christian Weiss , Ismail Zahed