Nuclear Commons^™

High-Energy Η(′)Π Photoproduction And The Nature Of Exotic Waves, Glòria Montaña, Vincent Mathieu, Vanamali Shastry, Łukasz Bibrzycki, César Fernández-Ramírez, Nadine Hammoud, Robert J. Perry, Alessandro Pilloni, Arkaitz Rodas, Wyatt A. Smith, Adam P. Szczepaniak, Daniel Winney

Physics Faculty Publications

The observation of hybrid mesons in photoproduction experiments can provide essential insight into the inner workings of quantum chromodynamics in the strong coupling regime. In particular, the study of final η^(′)π states is of great interest due to the presence of the lowest lying hybrid candidate with manifestly exotic quantum numbers, the π₁ (1600). In this work, a double-vector exchange model with Reggeized ρ and ω trajectories is developed to describe the photoproduction of η^(′)π in the high-mass region. Results are presented for the differential cross sections and forward-backward asymmetries in the energy region of interest …

Reply To "Comment On "Qcd Factorization With Multihadron Fragmentation Functions"", T. C. Rogers, T. Rainaldi, M. Radici, A. Courtoy

Physics Faculty Publications

We respond to comments [D. Pitonyak, C. Cocuzza, A. Metz, A. Prokudin, and N. Sato, preceding Comment, Phys. Rev. D 113, 038901 (2026)] about our article, [Phys. Rev. D 111, 056001 (2025)]. We stand by our conclusions and defend them against the criticisms.

Small-𝑥 Asmptomatics Of The Leading-Twist Flavor Singlet Quark Tmds, Daniel Adamiak, M. Gabriel Santiago, Yossathorn Tawabutr

Physics Faculty Publications

In this paper, we investigate the small-𝑥 behavior of the flavor-singlet, leading-twist quark transverse-momentum-dependent parton distribution functions (TMDs) using the light-cone operator treatment. This formalism allows us to express TMD operators at small 𝑥 in terms of polarized dipole amplitudes, enabling a systematic approach to their small-𝑥 evolution. We derive the evolution equations for these TMDs and solve them within the large-𝑁𝑐 approximation under the linearized, double-logarithmic approximation, where 𝑁𝑐 represents the number of quark colors. Expanding on previous work on unpolarized and helicity TMDs, we present the small-𝑥 asymptotics for a comprehensive set of TMDs, including the Sivers function, …

Unpolarized Gpds At Small X And Non-Zero Skewness, Yuri V. Kovchegov, M. Gabriel Santiago, Huachen Sun

Physics Faculty Publications

We study the small-x asymptotics of unpolarized generalized parton distributions (GPDs) and generalized transverse momentum distributions (GTMDs). Unlike the previous works in the literature, we consider the case of non-zero (but small) skewness while allowing for non-linear contributions to the evolution equations. We first show that unpolarized GPDs and GTMDs at small x are related to the eikonal dipole amplitude N, whose small-x evolution is given by the BK/JIMWLK evolution equations, and to the odderon amplitude 𝒪, whose evolution is also known in the literature. We then show that the effect of non-zero skewness ξ ≠ 0 is to modify …

Search For The Y(2175) In The Photoproduction Cross Section Measurement Of 𝛾p → 𝜙𝜋⁺𝜋⁻P At Gluex, F. Afzal, M. Albrecht, M. Amaryan, S. Arrigo, V. Arroyave, A. Asaturyan, A. Austregesilo, Z. Baldwin, F. Barbosa, J. Barlow, E. Barriga, R. Barsotti, D. Barton, V. Baturin, V. V. Berdnikov, A. Berger, W. Boeglin, M. Boer, W. J. Briscoe, T. Britton, R. Brunner, S. Cao, C. Chen, E. Chudakov, G. Chung, P. L. Cole, O. Cortes, V. Crede, M. M. Dalton, D. Darulis, A. Deur, S. Dobbs, A. Dolgolenko, M. Dugger, R. Dzhygadlo, D. Ebersole, M. Edo, H. Egiyan, P. Eugenio, A. Fabrizi, C. Fanelli, S. Fang, M. Fritsch, S. Furletov, L. Gan, H. Gao, A. Gardner, A. Gasparian, D. I. Glazier, C. Gleason, K. Goetzen, B. Grube, J. Guo, A. Hamdi, J. Hernandez, K. Hernandez, N. D. Hoffman, D. Hornidge, G. M. Huber, P. Hurck, W. Imoehl, D. G. Ireland, M. M. Ito, I. Jaegle, N. S. Jarvis, T. Jeske, M. Jing, R. T. Jones, V. Mateev, M. Mccaughan, M. Mccracken, C. A. Meyer, R. Miskimen, R. E. Mitchell, P. Moran, F. Nerling, L. Ng, E. Nissen, S. Orešić, A. I. Ostrovidov, Z. Papandeou, L. Pentchev, K. J. Peters, L. Puthiya Veetil, S. Rakshit, J. Reinhold, A. Remington, J. Ritman, G. Rodriguez, K. Saldana, S. Schadmand, A. M. Schertz, K. Scheuer, A. Schmidt, R. A. Schumacher, J. Schwiening, M. Scott, N. Septian, P. Sharp, V. J. Shen, X. Shen, M. R. Shepherd, J. Sikes, H. Singh, A. Smith, E. S. Smith, A. Somov, J. R. Stevens, I. I. Strakovsky, B. Sumner, K. Suresh, V. V. Tarasov, S. Taylor, Y. Teymurazyan, A. Thiel, M. Thomson, T. Viducic, T. Whitlatch, Y. Wunderlich, B. Yu, J. Zarling, Z. Zhang, X. Zhou, B. Zihlmann, The Glue X Collaboration

Physics Faculty Publications

Based on 334 pb-¹ of photoproduction data collected with the GlueX detector at Jefferson Lab, we have measured for the first time the cross section of the exclusive reaction 𝛾 + p → φ(1020)π⁺π⁻p by reconstructing the final state K⁺K⁻π⁺π⁻p produced with a photon beam of energies between 8.0 and 11.6 GeV. Based on the measured differential cross section, we have performed a search for the strangeoniumlike exotic candidate Y(2175), recently renamed to φ(2170). This state has been reported by different e⁺e⁻ annihilation experiments and it is addressed here for the first time in a photoproduction experiment. We do not …

Nonlocal Nucleon Matrix Elements In The Rest Frame, Joe Karpie, Christopher Monahan, Anatoly Radyushkin

Physics Faculty Publications

Extracting parton structure from lattice quantum chromodynamics (QCD) calculations requires studying the coordinate scale 𝑧3 dependence of the matrix elements of bilocal operators. The most significant contribution comes from the 𝑧3 dependence induced by ultraviolet (UV) renormalization of the Wilson line. We demonstrate that the next-to-leading order perturbative calculations of the renormalization factor can describe, to a few percent accuracy, the logarithm of the lattice QCD rest frame matrix elements with separations up to distances of 0.6 fm on multiple lattice spacings. The residual discrepancies can be modeled by a leading effect from the structure of the nucleon.

Small-X Gluon Gpd Constrained From Deeply Virtual J/Ψ Production And Gluon Pdf Through Universal-Moment Parametrization, Yuxun Guo, Xiangdong Ji, M. Gabriel Santiago, Jinghong Yang, Hao-Cheng Zhang

Physics Faculty Publications

We phenomenologically constrain the small-x and small-𝜉 gluon generalized parton distributions (GPDs) with the deeply virtual J/ψ production (DVJ/ψP) in the framework of GPDs through universal moment parameterization (GUMP). We use a hybrid cross-section formula combining collinear factorization to the next-to-leading order (NLO) accuracy of the strong coupling 𝛼_s, with corrections from nonrelativistic QCD to account for the power corrections due to the heavy J/ψ mass. We reach reasonable fit to the measured differential cross sections of DVJ/ψP by H1 at the Hadron-Electron Ring Accelerator as well as forward gluon parton distribution functions (PDFs) from JAM22 global analysis. …

Multidimensional Measurements Of Beam Single-Spin Asymmetries In Semi-Inclusive Deep-Inelastic Charged-Kaon Electroproduction Off Protons In The Valence Region, Clas Collaboration, A. Kripko, S. Diehl, K. Joo, P. Achenbach, J. S. Alvarado, M. Amaryan, W. R. Armstrong, H. Atac, H. Avakian, L. Baashen, N. A. Baltzell, L. Barion, L. Bashkanov, F. Benmokhtar, A. Bianconi, A. S. Biselli, M. Bondi, F. Bossù, S. Boiarinov, K. -T. Brinkmann, W. J. Briscoe, W. K. Brooks, T. Cao, R. Capobianco, D. S. Carman, J. C. Carvajal, A. Celentano, P. Chatagnon, G. Ciullo, P. L. Cole, M. Contalbrigo, V. Crede, A. D'Angelo, N. Dashyan, R. De Vita, M. Defurne, A. Deur, C. Dilks, C. Djalali, R. Dupre, H. Egiyan, A. El Alaoui, L. El Fassi, L. Elouadrhiri, S. Fegan, I. P. Fernando, A. Filippi, G. Gavalian, G. P. Gilfoyle, D. I. Glazier, R. W. Gothe, Y. Gotra, K. Hafidi, H. Hakobyan, M. Hattawy, F. Hauenstein, T. B. Hayward, D. Heddle, A. Hobart, M. Holtrop, Y. Ilieva, D. G. Ireland, E. L. Isupov, H. Jiang, H. S. Jo, T. Kageya, A. Kim, W. Kim, V. Klimenko, V. Kubarovsky, S. E. Kuhn, L. Lanza, P. Lenisa, X. Li, Z. Lu, I. J. D. Macgregor, D. Marchand, D. Martiryan, V. Mascagna, D. Matamoros, M. Maynes, B. Mckinnon, R. G. Milner, T. Mineeva, M. Mirazita, V. Mokeev, C. Munoz Camacho, P. Nadel-Turonski, T. Nagorna, K. Neupane, D. Nguyen, S. Niccolai, G. Niculescu, M. Osipenko, M. Ouillon, P. Pandey, L. L. Pappalardo, R. Paremuzyan, E. Pasyuk, S. J. Paul, N. Pilleux, S. Polcher Rafael, J. Poudel, J. W. Price, Y. Prok, T. Reed, M. Ripani, J. Ritman, C. D. Roberts, P. Rossi, A. A. Rusova, S. Schadmand, A. Schmidt, Y. G. Sharabian, E. V. Shirokov, S. Shrestha, U. Shrestha, D. Sokhan, N. Sparveris, M. Spreafico, I. I. Strakovsky, S. Strauch, R. Tyson, M. Ungaro, S. Vallarino, L. Venturelli, T. Vittorini, H. Voskanyan, A. Vossen, E. Voutier, Y. Wang, D. P. Watts, U. Weerasinghe, X. Wei, M. H. Wood, L. Xu, S. -S. Xu, N. Zachariou, V. Ziegler, M. Zurek

Physics Faculty Publications

Measurements of beam single-spin asymmetries in semi-inclusive deep-inelastic electron scattering (SIDIS) with positively charged kaons off protons have been performed with 10.6 and 10.2 GeV incident electron beams using the CLAS12 spectrometer at Jefferson Lab. We report an analysis of the electroproduction of positively charged kaons over a large kinematic range of fractional energy, Bjorken x, transverse momentum, and photon virtualities Q² ranging from 1 GeV² up to 6 GeV². This is the first published multidimensionally binned CLAS12 measurement of a kaon SIDIS single-spin asymmetry in the valence quark regime. The data provide constraints on the structure function ratio …

Development Of One And Two Current Transition Amplitudes With Two Body Final States, Keegan H. Sherman

Physics Theses & Dissertations

One of the biggest challenges facing modern day nuclear physics is understanding the structure of states within the hadronic spectrum of Quantum Chromodynamics (QCD). We have shown this spectrum to be quite rich with hundreds of allowed states; however, if we wish to better grasp the dynamics of QCD, then it is necessary that we start investigating the internal structure of these states. This may be done by probing these states with external currents, but this requires a description of the intersection of QCD with the electroweak sector. This work acts as a stepping stone in this direction. Working to …

Diffusion Model Approach To Simulating Electron-Proton Scattering Events, Peter Devlin, Jian-Wei Qiu, Felix Ringer, Nobuo Sato

Physics Faculty Publications

Generative artificial intelligence is a fast-growing area of research offering various avenues for exploration in high-energy nuclear physics. In this work, we explore the use of generative models for simulating electron-proton collisions relevant to experiments like the Continuous Electron Beam Accelerator Facility and the future Electron-Ion Collider (EIC). These experiments play a critical role in advancing our understanding of nucleons and nuclei in terms of quark and gluon degrees of freedom. The use of generative models for simulating collider events faces several challenges such as the sparsity of the data, the presence of global or eventwide constraints, and steeply falling …

Basics Of Factorization In A Scalar Yukawa Field Theory, F. Aslan, L. Gamberg, J.O. Gonzalez-Hernandez, T. Rainaldi, T. C. Rogers

Physics Faculty Publications

The factorization theorems of QCD apply equally well to most simple quantum field theories that require renormalization but where direct calculations are much more straightforward. Working with these simpler theories is convenient for stress testing the limits of the factorization program and for examining general properties of the parton density functions or other correlation functions that might be necessary for a factorized description of a process. With this view in mind, we review the steps of factorization in a real scalar Yukawa field theory for both deep inelastic scattering and semi-inclusive deep inelastic scattering cross sections. In the case of …

Deeply Virtual Compton Scattering Using A Positron Beam In Hall C, V. Berdnikov, A. Camsonne, M. Carmignotto, R. Ent, J. Grames, D. Higinbotham, C. Keppel, M. Mccaughan, P. Paremuzyan, B. Sawatzky, A. Somov, B. Wojtsekhowski, S. Wood, C. Zorn, R. Dupré, M. Ehrhart, M. Guidal, S. Habet, A. Hobart, D. Marchand, C. Muñoz Camacho, S. Niccolai, E. Voutier, M. Mazouz, T. Horn, G. Kalicy, M. Muhoza, I. Pegg, R. Trotta, A. Asaturyan, A. Mkrtchyan, H. Mkrtchyan, V. Tadevosyan, H. Voskanyan, S. Zhamkochyan, M. Amaryan, C. Hyde, M. Kerver, J. Murphy, J. Roche, P. Markowitz, A. Afanasev, W. J. Briscoe, I. Strakovsky, M. Boer, T. Forest, J.R.M. Annand, D. J. Hamilton, B. Mckinnon, D. Day, M. A. I. Fernando, D. Keller, R. Rondon, J. Zhang, K. Brinkmann, S. Diehl, R. Novotny, P. Gueye, V. Bellini, D. Dutta, E. Kinney, P. Nadel-Turonski, G. Niculescu, S. Sirca, I. Albayrak, M. Defurne, Z. Huang, Z. Ye

Physics Faculty Publications

We propose to use the High Momentum Spectrometer of Hall C combined with Neutral Particle Spectrometer (NPS) to perform high precision measurement of the deeply virtual compton scattering (DVCS) cross section using a beam of positrons. The combination of measurements with oppositely charged incident beams is the only unambiguous way to disentange the contribution of the DVCS² term in the photon electroproduction cross section from its interference with the Bethe-Heitler amplitude. This provies a stronger way to constrain the Generalized Parton Distributions of the nucleon. A range of kinematics accessible with an 11 GeV beam off an unpolarized proton target …

Collinear Factorization At Subasymptotic Kinematics And Validation In A Diquark Spectator Model, Juan V. Guerrero, Alberto Accardi

Physics Faculty Publications

We revisit the derivation of collinear factorization for Deep Inelastic Scattering at subasymptotic values of the four-momentum transfer squared, where the masses of the particles participating in the interaction cannot be neglected. By using an inclusive jet function to describe the scattered quark final state, we can restrict the needed parton kinematic approximations just to the four-momentum conservation of the hard scattering process, and explicitly expand the rest of the diagram in powers of the unobserved parton transverse momenta rather than neglecting those. This procedure provides one with more flexibility in fixing the virtuality of the scattered and recoiling partons …

Measurement Of Charged-Pion Production In Deep-Inelastic Scattering Off Nuclei With The Clas Detector, Clas Collaboration, S. Morán, R. Dupre, H. Hakobyan, Moskov J. Amaryan, Dilini Bulumulla, Mohammad Hattawy, Florian Hauenstein, Sebastian Kuhn, Pushpa Pandey, Jiwan Poudel, Yelena Prok, Lawrence B. Weinstein, N. Zachariou, J. Zhang, Z. W. Zhao, Et Al.

Physics Faculty Publications

Background: Energetic quarks in nuclear deep-inelastic scattering propagate through the nuclear medium. Processes that are believed to occur inside nuclei include quark energy loss through medium-stimulated gluon bremsstrahlung and intranuclear interactions of forming hadrons. More data are required to gain a more complete understanding of these effects.

Purpose: To test the theoretical models of parton transport and hadron formation, we compared their predictions for the nuclear and kinematic dependence of pion production in nuclei.

Methods: We have measured charged-pion production in semi-inclusive deep-inelastic scattering off D, C, Fe, and Pb using the CLAS detector and the CEBAF 5.014-GeV electron beam. …

Measurement Of The Nucleon FN₂/FP₂ Structure Function Ratio By The Jefferson Lab Marathon Tritium/Helium-3 Deep Inelastic Scattering Experiment, D. Abrams, H. Albataineh, B. S. Aljawrneh, S. Alsalmi, D. Androic, K. Aniol, W. Armstrong, J. Arrington, H. Atac, T. Averett, C. Ayerbe Gayoso, X. Bai, J. Bane, J. Barcus, A. Beck, V. Bellini, H. Bhatt, D. Bhetuwal, D. Biswas, D. Blyth, W. Boeglin, D. Bulumulla, Et Al.

Physics Faculty Publications

The ratio of the nucleon F₂ structure functions, Fⁿ₂/F^p₂, is determined by the MARATHON experiment from measurements of deep inelastic scattering of electrons from ³H and ³He nuclei. The experiment was performed in the Hall A Facility of Jefferson Lab using two high-resolution spectrometers for electron detection, and a cryogenic target system which included a low-activity tritium cell. The data analysis used a novel technique exploiting the mirror symmetry of the two nuclei, which essentially eliminates many theoretical uncertainties in the extraction of the ratio. The results, which cover the Bjorken …

Deeply Virtual Compton Scattering Cross Section At High Bjorken 𝓍B, F. Georges, M.N.H. Rashad, A. Stefanko, J. Zhang, Y. Zhao, P. Zhu, Et Al.

Physics Faculty Publications

We report high-precision measurements of the deeply virtual Compton scattering (DVCS) cross section at high values of the Bjorken variable 𝓍_B. DVCS is sensitive to the generalized parton distributions of the nucleon, which provide a three-dimensional description of its internal constituents. Using the exact analytic expression of the DVCS cross section for all possible polarization states of the initial and final electron and nucleon, and final state photon, we present the first experimental extraction of all four helicity-conserving Compton form factors (CFFs) of the nucleon as a function of 𝓍_B, while systematically including helicity flip amplitudes. …

Unpolarized Gluon Distribution In The Nucleon From Lattice Quantum Chromodynamics, Tanjib Khan, Raza Sabbir Sufian, Joseph Karpie, Christopher J. Monahan, Colin Egerer, Bálint Joó, Wayne Morris, Kostas Orginos, Anatoly Radyushkin, David G. Richards, Eloy Romero, Savvas Zafeiropoulos, On Behalf Of The Hadstruc Collaboration

Physics Faculty Publications

In this study, we present a determination of the unpolarized gluon Ioffe-time distribution in the nucleon from a first principles lattice quantum chromodynamics calculation. We carry out the lattice calculation on a 32³ × 64 ensemble with a pion mass of 358 MeV and lattice spacing of 0.094 fm. We construct the nucleon interpolating fields using the distillation technique, flow the gauge fields using the gradient flow, and solve the summed generalized eigenvalue problem to determine the gluonic matrix elements. Combining these techniques allows us to provide a statistically well-controlled Ioffe-time distribution and unpolarized gluon parton distribution function. We …

First Measurement Of Timeline Compton Scattering, P. Chatagnon, S. Niccolai, S. Stepanyan, M. J. Amaryan, C. E. Hyde, S. E. Kuhn, P. Pandey, Jiwan Poudel, Y. Prok, N. Zachariou, J. Zhang, Z. W. Zhao, Et Al., Clas Collaboration

Physics Faculty Publications

We present the first measurement of the timelike Compton scattering process, 𝛾p →p′𝛾^∗(𝛾^∗→e⁺e⁻), obtained with the CLAS12 detector at Jefferson Lab. The photon beam polarization and the decay lepton angular asymmetries are reported in the range of timelike photon virtualities 2.25 < Q² < 9  GeV², squared momentum transferred 0.1 < −t < 0.8  GeV², and average total center-of-mass energy squared s = 14.5  GeV² . The photon beam polarization asymmetry, similar to the beam-spin asymmetry in deep virtual Compton scattering, is sensitive to the imaginary part of the Compton form factors and provides a …

P-Wave Nucleon-Pion Scattering Amplitude In The Δ(1232) Channel From Lattice Qcd, Giorgio Silvi, Srijit Paul, Constantia Alexandrou, Stefan Krieg, Luka Leskovec, Stefan Meinel, John Negele, Marcus Petschlies, Andrew Pochinsky, Gumaro Rendon, Sergey Syritsyn, Antonio Todaro

Physics Faculty Publications

We determine the Δ(1232) resonance parameters using lattice QCD and the Lüscher method. The resonance occurs in elastic pion-nucleon scattering with J^P = 3/2⁺ in the isospin I=3/2, P-wave channel. Our calculation is performed with N_f = 2+1 flavors of clover fermions on a lattice with L ≈ 2.8 fm. The pion and nucleon masses are m_π = 255.4 (1.6) MeV and mN = 1073(5) MeV, respectively, and the strong decay channel Δ → _πN is found to be above the threshold. To thoroughly map out the energy dependence of the nucleon-pion …

Origin Of Single Transverse-Spin Asymmetries In High-Energy Collisions, Justin Cammarota, Leonard Gamberg, Zhong-Bo Kang, Joshua A. Miller, Daniel Pitonyak, Alexei Prokudin, Ted C. Rogers, Nobuo Sato

Physics Faculty Publications

In this paper, we perform the first simultaneous QCD global analysis of data from semi-inclusive deep inelastic scattering, Drell-Yan, 𝑒⁺⁢𝑒⁻ annihilation into hadron pairs, and proton-proton collisions. Consequently, we are able to extract a universal set of nonperturbative functions that describes the observed asymmetries in these reactions. The outcome of our analysis indicates single transverse-spin asymmetries in high-energy collisions have a common origin. Furthermore, we achieve the first phenomenological agreement with lattice QCD on the up and down quark tensor charges.

Jeopardy Update On E12-06-106: Rg-D Experiment Study Of Color Transparency In Exclusive Vector Meson Electroproduction Off Nuclei, W. Armstrong, C. Ayerbe, W. Brooks, T. Chetry, R. Dupré, D. Dutta, A. El Alaoui, L. El Fassi, S. Joosten, J. Kim, K. Hafidi, M. Hattawy, M. Holtrop, J. Lopez, Z. -E. Meziani, T. Mineeva, B. Mustapha, C. Peng, L. Weinstein, J. Xie

Physics Faculty Publications

Experiment E12-06-106 (RG-D) aims to study the color transparency (CT) phenomenon in the exclusive diffractive p⁰ electro-production off nuclei, using the CLAS-12 spectrometer in Hall-B. This experiment was endorsed by PAC30 back in 2006 and was reviewed by PAC36 in 2010 [1], at which time it was approved for 60 PAC days and granted the B⁺ rating.

CT is one of the underlying properties of Quantum Chromo Dynamics (QCD) related to the presence of color degrees of freedom in the strongly interacting matter. It refers to the suppression of interactions of the colorless small size configuration in the nuclear …

Neutron Valence Structure From Nuclear Deep Inelastic Scattering, E. P. Segarra, A. Schmidt, T. Kutz, D. W. Higinbotham, E. Piasetzky, M. Strikman, L. B. Weinstein, O. Hen

Physics Faculty Publications

Mechanisms of spin-flavor SU(6) symmetry breaking in quantum chromodynamics (QCD) are studied via an extraction of the free neutron structure function from a global analysis of deep inelastic scattering (DIS) data on the proton and on nuclei from A = 2 (deuterium) to 208 (lead). Modification of the structure function of nucleons bound in atomic nuclei (known as the EMC effect) are consistently accounted for within the framework of a universal modification of nucleons in short-range correlated (SRC) pairs. Our extracted neutron-to-proton structure function ratio Fⁿ₂/F^p₂ becomes constant for x_B ≥ 0.6, equaling 0.47 …

Conformal Invariance Of Transverse-Momentum Dependent Parton Distributions Rapidity Evolution, Ian Balitsky, Giovanni A. Chirilli

Physics Faculty Publications

We discuss conformal properties of TMD operators and present the result of the conformal rapidity evolution of TMD operators in the Sudakov region.

Measurement Of Unpolarized And Polarized Cross Sections For Deeply Virtual Compton Scattering On The Proton At Jefferson Laboratory With Clas, N. Hirlinger Saylor, B. Guegan, V. D. Burkert, L. Elouadrhiri, M. Garçon, F. X. Girod, M. Guidal, H. S. Jo, V. Kubarovsky, S. Niccolai, P. Stoler, K. P. Adhikari, S. Adhikari, Z. Akbar, M. J. Amaryan, S. Anefalos Pereira, J. Ball, I. Balossino, N. A. Baltzell, L. Barion, M. Battaglieri, V. Batourine, I. Bedlinskiy, A. S. Biselli, S. Boiarinov, W. J. Briscoe, W. K. Brooks, S. Bültmann, F. Cao, S. Carman, Wesley P. Gohn

Physics and Astronomy Faculty Publications

This paper reports the measurement of polarized and unpolarized cross sections for the ep → e′ p′ γ reaction, which is composed of deeply virtual Compton scattering (DVCS) and Bethe-Heitler (BH) processes, at an electron beam energy of 5.88 GeV at the Thomas Jefferson National Accelerator Facility using the Large Acceptance Spectrometer CLAS. The unpolarized cross sections and polarized cross section differences have been measured over broad kinematics, 0.10 < x_B < 0.58, 1.0 < Q² < 4.8GeV², and 0.09 < −t < 2.00GeV². The results are found to be consistent with previous CLAS data, and these new data are discussed in …

Resonances From Lattice Qcd, Raúl A. Briceño

Physics Faculty Publications

The spectrum of hadron is mainly composed as shortly-lived states (resonance) that decay onto two or more hadrons. These resonances play an important role in a variety of phenomenologically significant processes. In this talk, I give an overview on the present status of a rigorous program for studying of resonances and their properties using lattice QCD. I explain the formalism needed for extracting resonant amplitudes from the finite-volume spectra. From these one can extract the masses and widths of resonances. I present some recent examples that illustrate the power of these ideas. I then explain similar formalism that allows for …

Measurements Of The Separated Longitudinal Structure Function Fl From Hydrogen And Deuterium Targets At Low Q2, V. Tvaskis, A. Tvaskis, I. Niculescu, D. Abbott, G. S. Adams, A. Afanasev, A. Ahmidouch, T. Angelescu, J. Arrington, A. Klein

Physics Faculty Publications

Structure functions, as measured in lepton-nucleon scattering, have proven to be very useful in studying the partonic dynamics within the nucleon. However, it is experimentally difficult to separately determine the longitudinal and transverse structure functions, and consequently there are substantially less data available in particular for the longitudinal structure function. Here, we present separated structure functions for hydrogen and deuterium at low four-momentum transfer squared, Q² < 1GeV², and compare them with parton distribution parametrization and k_T factorization approaches. While differences are found, the parametrizations generally agree with the data, even at the very low-Q² scale of …

Glue Spin And Helicity In The Proton From Lattice Qcd, Yi-Bo Yang, Raza Sabbir Sufian, Andrei Alexandru, Terrence Draper, Michael J. Glatzmaier, Keh-Fei Liu, Yong Zhao

Physics and Astronomy Faculty Publications

We report the first lattice QCD calculation of the glue spin in the nucleon. The lattice calculation is carried out with valence overlap fermions on 2 + 1 flavor domain-wall fermion gauge configurations on four lattice spacings and four volumes including an ensemble with physical values for the quark masses. The glue spin SG in the Coulomb gauge in the modified minimal subtraction (MS¯) scheme is obtained with one-loop perturbative matching. We find the results fairly insensitive to lattice spacing and quark masses. We also find that the proton momentum dependence of S_G in the range 0 ≤ |p …

Locality And Efficient Evaluation Of Lattice Composite Fields: Overlap-Based Gauge Operators, Andrei Alexandru, Ivan Horváth

Physics and Astronomy Faculty Publications

We propose a novel general approach to locality of lattice composite fields, which in case of QCD involves locality in both quark and gauge degrees of freedom. The method is applied to gauge operators based on the overlap Dirac matrix elements, showing for the first time their local nature on realistic path-integral backgrounds. The framework entails a method for efficient evaluation of such nonultralocal operators, whose computational cost is volume independent at fixed accuracy, and only grows logarithmically as this accuracy approaches zero. This makes computation of useful operators, such as overlap-based topological density, practical. The key notion underlying these …

Polarized Light Ions And Spectator Nucleon Tagging At Eic, V. Guzey, D. Higinbotham, C. Hyde, P. Nadel-Turonski, K. Park, M. Sargsian, M. Strikman, C. Weiss

Physics Faculty Publications

An Electron-Ion Collider (EIC) with suitable forward detection capabilities would enable a unique experimental program of deep-inelastic scattering (DIS) from polarized light nuclei (deuterium ²H, helium ³He) with spectator nucleon tagging. Such measurements promise significant advances in several key areas of nuclear physics and QCD: (a) neutron spin structure, by using polarized deuterium and eliminating nuclear effects through on-shell extrapolation in the spectator proton momentum; (b) quark/gluon structure of the bound nucleon at x > 0.1 and the dynamical mechanisms acting on it, by measuring the spectator momentum dependence of nuclear structure functions; (c) coherent effects in QCD, by exploring shadowing …

Virtuality Distributions In Application To Ɣɣ* → Π​0 Transition Form Factor At Handbag Level, Anatoly V. Radyushkin

Physics Faculty Publications

We outline basics of a new approach to transverse momentum dependence in hard processes. As an illustration, we consider hard exclusive transition process ɣ*ɣ -> π⁰ at the handbag level. Our starting point is coordinate representation for matrix elements of operators (in the simplest case, bilocal O(0, z)) describing a hadron with momentum p. Treated as functions of (pz) and z², they are parametrized through virtuality distribution amplitudes (VDA) Φ(x, σ), with x being Fourier-conjugate to (pz) and σ Laplace-conjugate to z². For intervals with z⁺ = 0, we introduce the transverse momentum distribution …