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Hunt-Smith N, Accardi A, Melnitchouk W, Sato N, Thomas A, White M. Determination of uncertainties in parton densities. Int J Clin Exp Med 2022. [DOI: 10.1103/physrevd.106.036003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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2
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Karthik N, Narayanan R. Parton physics of the large-
Nc
mesons. Int J Clin Exp Med 2022. [DOI: 10.1103/physrevd.106.014503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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3
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Chávez JMM, Bertone V, De Soto Borrero F, Defurne M, Mezrag C, Moutarde H, Rodríguez-Quintero J, Segovia J. Accessing the Pion 3D Structure at US and China Electron-Ion Colliders. PHYSICAL REVIEW LETTERS 2022; 128:202501. [PMID: 35657889 DOI: 10.1103/physrevlett.128.202501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 12/22/2021] [Accepted: 03/03/2022] [Indexed: 06/15/2023]
Abstract
We present the first systematic feasibility study of accessing generalized parton distributions of the pion at an electron-ion collider through deeply virtual Compton scattering. Relying on state-of-the-art models for pion GPDs, we show that quarks and gluons interfere destructively, modulating the expected event rate and maximizing it when parton content is generated via radiation from valence dressed quarks. Moreover, gluons are found to induce a sign inversion for the beam-spin asymmetry in every model studied, being a clear signal for pinning down the regime of gluon superiority.
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Affiliation(s)
- José Manuel Morgado Chávez
- Department of Integrated Sciences and Center for Advanced Studies in Physics, Mathematics and Computation, University of Huelva, E-21071 Huelva, Spain
| | - Valerio Bertone
- Irfu, CEA, Université Paris-Saclay, 91191 Gif-sur-Yvette, France
| | - Feliciano De Soto Borrero
- Departamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide, E-41013 Sevilla, Spain
| | - Maxime Defurne
- Irfu, CEA, Université Paris-Saclay, 91191 Gif-sur-Yvette, France
| | - Cédric Mezrag
- Irfu, CEA, Université Paris-Saclay, 91191 Gif-sur-Yvette, France
| | - Hervé Moutarde
- Irfu, CEA, Université Paris-Saclay, 91191 Gif-sur-Yvette, France
| | - José Rodríguez-Quintero
- Department of Integrated Sciences and Center for Advanced Studies in Physics, Mathematics and Computation, University of Huelva, E-21071 Huelva, Spain
| | - Jorge Segovia
- Departamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide, E-41013 Sevilla, Spain
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4
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Cichy K. Overview of lattice calculations of the x-dependence of PDFs, GPDs and TMDs. EPJ WEB OF CONFERENCES 2022. [DOI: 10.1051/epjconf/202225801005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
For a long time, lattice QCD was unable to address the x-dependence of partonic distributions, direct access to which is impossible in Euclidean spacetime. Recent years have brought a breakthrough for such calculations when it was realized that partonic light-cone correlations can be accessed through spatial correlations computable on the lattice. Appropriately devised observables can be factorized into physical PDFs via a perturbative procedure called matching, analogous to the standard factorization of experimental cross sections. In this short review, aimed at a broader high-energy and nuclear physics community, we discuss the recent highlights of this research program. Key concepts are outlined, followed by a case study illustrating the typical stage of current lattice extractions and by a brief review of the most recent explorations. We finalize with a number of messages for the prospects of lattice determinations of partonic structure.
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5
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Gao X, Karthik N, Mukherjee S, Petreczky P, Syritsyn S, Zhao Y. Pion form factor and charge radius from lattice QCD at the physical point. Int J Clin Exp Med 2021. [DOI: 10.1103/physrevd.104.114515] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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6
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Alexandrou C, Bacchio S, Bergner G, Finkenrath J, Gasbarro A, Hadjiyiannakou K, Jansen K, Kostrzewa B, Ottnad K, Petschlies M, Pittler F, Steffens F, Urbach C, Wenger U. Quark and Gluon Momentum Fractions in the Pion from N_{f}=2+1+1 Lattice QCD. PHYSICAL REVIEW LETTERS 2021; 127:252001. [PMID: 35029455 DOI: 10.1103/physrevlett.127.252001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 11/03/2021] [Indexed: 06/14/2023]
Abstract
We perform the first full decomposition of the pion momentum into its gluon and quark contributions. We employ an ensemble generated by the Extended Twisted Mass Collaboration with N_{f}=2+1+1 Wilson twisted mass clover fermions at maximal twist tuned to reproduce the physical pion mass. We present our results in the MS[over ¯] scheme at 2 GeV. We find ⟨x⟩_{u+d}=0.601(28), ⟨x⟩_{s}=0.059(13), ⟨x⟩_{c}=0.019(05), and ⟨x⟩_{g}=0.52(11) for the separate contributions, respectively, whose sum saturates the momentum sum rule.
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Affiliation(s)
- Constantia Alexandrou
- Department of Physics, University of Cyprus, Nicosia 2109, Cyprus
- Computation-based Science and Technology Research Center, The Cyprus Institute, Nicosia 2121, Cyprus
| | - Simone Bacchio
- Computation-based Science and Technology Research Center, The Cyprus Institute, Nicosia 2121, Cyprus
| | - Georg Bergner
- Institute of Theoretical Physics, Friedrich Schiller University Jena, Jena 07743, Germany
| | - Jacob Finkenrath
- Computation-based Science and Technology Research Center, The Cyprus Institute, Nicosia 2121, Cyprus
| | - Andrew Gasbarro
- Albert Einstein Center, Institute for Theoretical Physics, University of Bern, Bern CH-3012, Switzerland
| | - Kyriakos Hadjiyiannakou
- Department of Physics, University of Cyprus, Nicosia 2109, Cyprus
- Computation-based Science and Technology Research Center, The Cyprus Institute, Nicosia 2121, Cyprus
| | | | - Bartosz Kostrzewa
- High Performance Computing and Analytics Lab, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn 53115, Germany
| | - Konstantin Ottnad
- PRISMA+ Cluster of Excellence and Institut für Kernphysik, Johannes Gutenberg-Universität Mainz, Mainz 55099, Germany
| | - Marcus Petschlies
- Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, Bonn 53115, Germany
- Bethe Center for Theoretical Physics, University of Bonn, Bonn 53115, Germany
| | - Ferenc Pittler
- Computation-based Science and Technology Research Center, The Cyprus Institute, Nicosia 2121, Cyprus
| | - Fernanda Steffens
- Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, Bonn 53115, Germany
- Bethe Center for Theoretical Physics, University of Bonn, Bonn 53115, Germany
| | - Carsten Urbach
- Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, Bonn 53115, Germany
- Bethe Center for Theoretical Physics, University of Bonn, Bonn 53115, Germany
| | - Urs Wenger
- Albert Einstein Center, Institute for Theoretical Physics, University of Bern, Bern CH-3012, Switzerland
- Department of Theoretical Physics, CERN, Geneva CH-1211, Switzerland
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7
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Barry PC, Ji CR, Sato N, Melnitchouk W. Global QCD Analysis of Pion Parton Distributions with Threshold Resummation. PHYSICAL REVIEW LETTERS 2021; 127:232001. [PMID: 34936801 DOI: 10.1103/physrevlett.127.232001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 10/22/2021] [Accepted: 10/26/2021] [Indexed: 06/14/2023]
Abstract
We perform the first global QCD analysis of pion valence, sea quark, and gluon distributions within a Bayesian Monte Carlo framework with threshold resummation on Drell-Yan cross sections at next-to-leading log accuracy. Exploring various treatments of resummation, we find that the large-x asymptotics of the valence quark distribution ∼(1-x)^{β_{v}} can differ significantly, with β_{v} ranging from ≈1 to >2.5 at the input scale. Regardless of the specific implementation, however, the resummation induced redistribution of the momentum between valence quarks and gluons boosts the total momentum carried by gluons to ≈40%, increasing the gluon contribution to the pion mass to ≈40 MeV.
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Affiliation(s)
- P C Barry
- Jefferson Lab, Newport News, Virginia 23606, USA
| | - Chueng-Ryong Ji
- Department of Physics, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - N Sato
- Jefferson Lab, Newport News, Virginia 23606, USA
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8
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Abstract
Examining the evolution of the maximum of valence quark distribution, qV, weighted by Bjorken x, h(x,t)≡xqV(x,t), it is observed that h(x,t) at the peak becomes a one-parameter function; h(xp,t)=Φ(xp(t)), where xp is the position of the peak, t=logQ2, and Q2 is the resolution scale. This observation is used to derive a new model-independent relation which connects the partial derivative of the valence parton distribution functions (PDFs) in xp to the quantum chromodynamics (QCD) evolution equation through the xp derivative of the logarithm of the function Φ(xp(t)). A numerical analysis of this relation using empirical PDFs results in an observation of the exponential form of the Φ(xp(t))=h(xp,t)=CeDxp(t) for leading to next-to-next leading order approximations of PDFs for the range of Q2, covering four orders in magnitude. The exponent, D, of the observed “height-position” correlation function converges with the increase in the order of approximation. This result holds for all the PDF sets considered. A similar relation is observed also for the pion valence quark distribution, indicating that the obtained relation may be universal for any non-singlet partonic distribution. The observed “height-position” correlation is used also to indicate that no finite number of exchanges can describe the analytic behavior of the valence quark distribution at the position of the peak at fixed Q2.
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9
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Karthik N, Sufian RS. Bayesian-Wilson coefficients in lattice QCD computations of valence PDFs and GPDs. Int J Clin Exp Med 2021. [DOI: 10.1103/physrevd.104.074506] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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10
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Constantinou M. The x-dependence of hadronic parton distributions: A review on the progress of lattice QCD. THE EUROPEAN PHYSICAL JOURNAL. A, HADRONS AND NUCLEI 2021; 57:77. [PMID: 33654456 PMCID: PMC7905977 DOI: 10.1140/epja/s10050-021-00353-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 01/13/2021] [Indexed: 06/12/2023]
Abstract
In this article, we review recent lattice calculations on the x-dependence of parton distributions, with the latter providing information on hadron structure. These calculations are based on matrix elements of boosted hadrons coupled to non-local operators and can be related to the standard, light-cone distribution functions via an appropriate factorization formalism. There is significant progress in several directions, including calculations of flavor-singlet parton distribution functions (PDFs), first calculations of generalized parton distributions (GPDs), as well as the implementation of some of the approaches for the transverse-momentum-dependent PDFs (TMD PDFs). This new direction of lattice calculations is particularly interesting for phenomenological fits on experimental data sets, as the lattice results can help improve the constraints on the distribution functions.
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11
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Alexandrou C, Bacchio S, Cloët I, Constantinou M, Hadjiyiannakou K, Koutsou G, Lauer C. Mellin moments
⟨x⟩
and
⟨x2⟩
for the pion and kaon from lattice QCD. Int J Clin Exp Med 2021. [DOI: 10.1103/physrevd.103.014508] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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12
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Cammarota J, Gamberg L, Kang ZB, Miller JA, Pitonyak D, Prokudin A, Rogers TC, Sato N. Origin of single transverse-spin asymmetries in high-energy collisions. Int J Clin Exp Med 2020. [DOI: 10.1103/physrevd.102.054002] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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13
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Abstract
The Lagrangian that defines quantum chromodynamics (QCD), the strong interaction piece of the Standard Model, appears very simple. Nevertheless, it is responsible for an astonishing array of high-level phenomena with enormous apparent complexity, e.g., the existence, number and structure of atomic nuclei. The source of all these things can be traced to emergent mass, which might itself be QCD’s self-stabilising mechanism. A background to this perspective is provided, presenting, inter alia, a discussion of the gluon mass and QCD’s process-independent effective charge and highlighting an array of observable expressions of emergent mass, ranging from its manifestations in pion parton distributions to those in nucleon electromagnetic form factors.
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14
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Ding M, Raya K, Binosi D, Chang L, Roberts CD, Schmidt SM. Symmetry, symmetry breaking, and pion parton distributions. Int J Clin Exp Med 2020. [DOI: 10.1103/physrevd.101.054014] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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15
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Bednar KD, Cloët IC, Tandy PC. Distinguishing Quarks and Gluons in Pion and Kaon Parton Distribution Functions. PHYSICAL REVIEW LETTERS 2020; 124:042002. [PMID: 32058777 DOI: 10.1103/physrevlett.124.042002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Indexed: 06/10/2023]
Abstract
The leading-twist parton distribution functions of the pion and kaon are calculated for the first time using a rainbow-ladder truncation of QCD's Dyson-Schwinger equations (DSEs) that self-consistently sums all planar diagrams. The nonperturbative gluon dressing of the quarks is thereby correctly accounted for, which in practice means solving the inhomogeneous Bethe-Salpeter equation (BSE) for the quark operator that defines the spin-independent quark distribution functions. An immediate consequence of using this dressed vertex is that gluons carry 35% of the pion's and 30% of the kaon's light-cone momentum, with the remaining momentum carried by the quarks. The scale associated with these DSE results is μ_{0}=0.78 GeV. The gluon effects generated by the inhomogeneous BSE are inherently nonperturbative and cannot be mimicked by the perturbative QCD evolution equations. A key consequence of this gluon dressing is that the valence quarks have reduced support at low-to-intermediate x, where the gluons dominate, and increased support at large x. As a result, our DSE calculation of the pion's valence quark distribution is in excellent agreement with the Conway et al. pion-induced Drell-Yan data, but nevertheless exhibits the q_{π}(x)≃(1-x)^{2} behavior as x→1 predicted by perturbative QCD.
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Affiliation(s)
- Kyle D Bednar
- Center for Nuclear Research, Department of Physics, Kent State University, Kent Ohio 44242, USA
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Ian C Cloët
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Peter C Tandy
- Center for Nuclear Research, Department of Physics, Kent State University, Kent Ohio 44242, USA
- CSSM, Department of Physics, University of Adelaide, Adelaide South Australia 5005, Australia
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16
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Lan J, Mondal C, Jia S, Zhao X, Vary JP. Parton Distribution Functions from a Light Front Hamiltonian and QCD Evolution for Light Mesons. PHYSICAL REVIEW LETTERS 2019; 122:172001. [PMID: 31107088 DOI: 10.1103/physrevlett.122.172001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 03/19/2019] [Indexed: 06/09/2023]
Abstract
We obtain the pion and the kaon parton distribution functions from the eigenstates of a light front effective Hamiltonian in the constituent quark-antiquark representation suitable for low-momentum scale applications. By taking these scales as the only free parameters, the valence quark distribution functions of the pion, after QCD evolution, are consistent with the data from the FNAL-E615 experiment. The ratio of the up quark distribution of the kaon to that of the pion also agrees with the CERN-NA3 experiment. Supplemented by known parton distribution functions for the nucleons, we further obtain the cross section consistent with experimental data for the π^{-}nucleus→μ^{+}μ^{-}X Drell-Yan process.
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Affiliation(s)
- Jiangshan Lan
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chandan Mondal
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Shaoyang Jia
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - Xingbo Zhao
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - James P Vary
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
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