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Physics Faculty Publications

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Articles 121 - 150 of 1942

Full-Text Articles in Physical Sciences and Mathematics

New Results At Jlab Describing Operating Lifetime Of Gaas Photo-Guns, M. Bruker, J. Grames, C. Hernández-García, M. Poelker, S. Zhang, V. Lizárraga-Rubio, C. Valerio-Lizárraga, Joshua T. Yoskowitz Jan 2022

New Results At Jlab Describing Operating Lifetime Of Gaas Photo-Guns, M. Bruker, J. Grames, C. Hernández-García, M. Poelker, S. Zhang, V. Lizárraga-Rubio, C. Valerio-Lizárraga, Joshua T. Yoskowitz

Physics Faculty Publications

Polarized electrons from GaAs photocathodes have been key to some of the highest-impact results of the Jefferson Lab science program over the past 30 years. During this time, various studies have given insight into improving the operational lifetime of these photocathodes in DC high-voltage photo-guns while using lasers with spatial Gaussian profiles of typically 0.5 mm to 1 mm FWHM, cathode voltages of 100 kV to 130 kV, and a wide range of beam currents up to multiple mA. In this contribution, we show recent experimental data from a 100 kV to 180 kV setup and describe our progress at …

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197 Mhz Waveguide Loaded Crabbing Cavity Design For The Electron-Ion Collider, Subashini De Silva, Jean Delayen, J. Guo, R. A. Rimmer, Z. Li, B. P. Xiao Jan 2022

197 Mhz Waveguide Loaded Crabbing Cavity Design For The Electron-Ion Collider, Subashini De Silva, Jean Delayen, J. Guo, R. A. Rimmer, Z. Li, B. P. Xiao

Physics Faculty Publications

The Elec­tron-Ion Col­lider will re­quire crab­bing sys­tems at both hadron and elec­tron stor­age rings in order to reach the de­sired lu­mi­nos­ity goal. The 197 MHz crab cav­ity sys­tem is one of the crit­i­cal rf sys­tems of the collider. The crab cav­ity, based on the rf-di­pole de­sign, explores the op­tion of wave­guide load damp­ing to sup­press the higher order modes and meet the tight im­ped­ance spec­i­fi­ca­tions. The cav­ity is de­signed with com­pact dog-bone wave­guides with tran­si­tions to rec­tan­gu­lar wave-guides and wave­guide loads. This paper pre­sents the com­pact 197 MHz crab cav­ity de­sign with wave­guide damp­ing and other an­cil­lar­ies.

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Question 1: Snow Volume; Question 2: Longbow Arrow Velocity, Larry Weinstein Jan 2022

Question 1: Snow Volume; Question 2: Longbow Arrow Velocity, Larry Weinstein

Physics Faculty Publications

No abstract provided.

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X17 Boson And The ³H(P, E⁺E⁻) ⁴He And ³He(N,E⁺E⁻) ⁴He Processes: A Theoretical Analysis, M. Viviani, E. Filandri, C. Gustavino, A. Kievsky, L. E. Marcucci, Rocco Schiavilla Jan 2022

X17 Boson And The ³H(P, E⁺E⁻) ⁴He And ³He(N,E⁺E⁻) ⁴He Processes: A Theoretical Analysis, M. Viviani, E. Filandri, C. Gustavino, A. Kievsky, L. E. Marcucci, Rocco Schiavilla

Physics Faculty Publications

The present work deals with e+−e− pair production in the four-nucleon system. We first analyze the process as a purely electromagnetic one in the context of a state-of-the-art approach to nuclear strong-interaction dynamics and nuclear electromagnetic currents, derived from chiral effective field theory (χEFT). Next, we examine how the exchange of a hypothetical low-mass boson would impact the cross section for such a process. We consider several possibilities, that this boson is either a scalar, pseudoscalar, vector, or axial particle. The ab initio calculations use exact hyperspherical-harmonics methods to describe the bound state and low-energy spectrum of …

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A Laser Frequency Transverse Modulation Might Compensate For The Spectral Broadening Due To Large Electron Energy Spread In Thomson Sources, Vittoria Petrillo, Illya Drebot, Geoffrey Krafft, Cesare Maroli, Andrea R. Rossi, Marcello Rossetti Conti, Marcel Ruijter, Balša Terzić Jan 2022

A Laser Frequency Transverse Modulation Might Compensate For The Spectral Broadening Due To Large Electron Energy Spread In Thomson Sources, Vittoria Petrillo, Illya Drebot, Geoffrey Krafft, Cesare Maroli, Andrea R. Rossi, Marcello Rossetti Conti, Marcel Ruijter, Balša Terzić

Physics Faculty Publications

Compact laser plasma accelerators generate high-energy electron beams with increasing quality. When used in inverse Compton backscattering, however, the relatively large electron energy spread jeopardizes potential applications requiring small bandwidths. We present here a novel interaction scheme that allows us to compensate for the negative effects of the electron energy spread on the spectrum, by introducing a transverse spatial frequency modulation in the laser pulse. Such a laser chirp, together with a properly dispersed electron beam, can substantially reduce the broadening of the Compton bandwidth due to the electron energy spread. We show theoretical analysis and numerical simulations for hard …

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Experimental Study Of The Behavior Of The Bjorken Sum At Very Low Q², A. Deur, J. P. Chen, S. E. Kuhn, C. Peng, M. Ripani, V. Sulkosky, K. Adhikari, M. Battaglieri, V. D. Burkert, G. D. Cates, R. De Vita, G.E. Dodge, L. El Fassi, F. Garibaldi, H. Kang, M. Osipenko, J. T. Singh, K. Slifer, J. Zhang, X. Zheng Jan 2022

Experimental Study Of The Behavior Of The Bjorken Sum At Very Low Q², A. Deur, J. P. Chen, S. E. Kuhn, C. Peng, M. Ripani, V. Sulkosky, K. Adhikari, M. Battaglieri, V. D. Burkert, G. D. Cates, R. De Vita, G.E. Dodge, L. El Fassi, F. Garibaldi, H. Kang, M. Osipenko, J. T. Singh, K. Slifer, J. Zhang, X. Zheng

Physics Faculty Publications

We present new data on the Bjorken sum -Γ p-n1 (Q2) at 4-momentum transfer 0.021 ≤ Q2 ≤ 0.496 GeV2. The data were obtained in two experiments performed at Jefferson Lab: EG4 on polarized protons and deuterons, and E97110 on polarized 3He from which neutron data were extracted. The data cover the domain where chiral effective field theory (χEFT), the leading effective theory of the Strong Force at large distances, is expected to be applicable. We find that our data and the predictions from χEFT are only in marginal …

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Short-Distance Structure Of Unpolarized Gluon Pseudodistributions, Ian Balitsky, Wayne Morris, Anatoly Radyushkin Jan 2022

Short-Distance Structure Of Unpolarized Gluon Pseudodistributions, Ian Balitsky, Wayne Morris, Anatoly Radyushkin

Physics Faculty Publications

We present the results that form the basis for calculations of the unpolarized gluon parton distributions (PDFs) using the pseudo-PDF approach. We give the results for the most complicated box diagram both for gluon bilocal operators with arbitrary indices and for combinations of indices corresponding to three matrix elements that are most convenient to extract the twist-2 invariant amplitude. We also present detailed results for the gluon-quark transition diagram. The additional results for the box diagram and the gluon-quark contribution may be used for extractions of the gluon PDF from different matrix elements, with a possible cross-check of the results …

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Transversity Parton Distribution Function Of The Nucleon Using The Pseudodistribution Approach, Colin Egerer, Christos Kallidonis, Joseph Karpie, Nikhil Karthik, Christopher J. Monahan, Wayne Morris, Kostas Orginos, Anatoly Radyushkin, Eloy Romero, Raza Sabbir Sufian, Savvas Zafeiropoulos, On Behalf Of The Hadstruc Collaboration Jan 2022

Transversity Parton Distribution Function Of The Nucleon Using The Pseudodistribution Approach, Colin Egerer, Christos Kallidonis, Joseph Karpie, Nikhil Karthik, Christopher J. Monahan, Wayne Morris, Kostas Orginos, Anatoly Radyushkin, Eloy Romero, Raza Sabbir Sufian, Savvas Zafeiropoulos, On Behalf Of The Hadstruc Collaboration

Physics Faculty Publications

We present a determination of the nonsinglet transversity parton distribution function (PDF) of the nucleon, normalized with respect to the tensor charge at μ2 ¼ 2 GeV2 from lattice quantum chromodynamics. We apply the pseudodistribution approach, using a gauge ensemble with a lattice spacing of 0.094 fm and the light quark mass tuned to a pion mass of 358 MeV. We extract the transversity PDF from the analysis of the short-distance behavior of the Ioffe-time pseudodistribution using the leading-twist nextto-leading order (NLO) matching coefficients calculated for transversity. We reconstruct the x-dependence of the transversity PDF through an expansion in a …

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Parton Distribution Function For Topological Charge At One Loop, Anatoly Radyushkin, Shuai Zhao Jan 2022

Parton Distribution Function For Topological Charge At One Loop, Anatoly Radyushkin, Shuai Zhao

Physics Faculty Publications

We present results for the gg-part of the one-loop corrections to the recently introduced “topological charge” GPD ~F(x, q2). In particular, we give expression for its evolution kernel. To enforce strict compliance with the gauge invariance requirements, we have used on-shell states for external gluons, and have obtained identical results both in Feynman and light-cone gauges. No “zero mode” δ(x) terms were found for the twist-4 gluon GPD ~F(x, q2).

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Polarized Gluon Pseudodistributions At Short Distances, Ian Balitsky, Wayne Morris, Anatoly Radyushkin Jan 2022

Polarized Gluon Pseudodistributions At Short Distances, Ian Balitsky, Wayne Morris, Anatoly Radyushkin

Physics Faculty Publications

We formulate the basic points of the pseudo-PDF approach to the lattice calculation of polarized gluon PDFs. We present the results of our calculations of the one-loop corrections for the bilocal Gμα(z)G̃λβ(0) correlator of gluonic fields. Expressions are given for a general situation when all four indices are arbitrary, and also for specific combinations of indices corresponding to three matrix elements that contain the twist-2 invariant amplitude related to the polarized PDF. We study the evolution properties of these matrix elements, and derive matching relations between Euclidean and light-cone Ioffe-time distributions. These relations are necessary for …

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Multidimensional, High Precision Measurements Of Beam Single Spin Asymmetries In Semi-Inclusive 𝜋⁺ Electroproduction Off Protons In The Valence Region, S. Diehl, A. Kim, G. Angelini, K. Joo, S. Adhikari, M. J. Amaryan, M. Arratia, H. Atac, H. Avakian, C. Ayerbe Gayoso, N. A. Baltzell, L. Barion, S. Bastami, M. Battaglieri, I. Bedlinskiy, F. Benmokhtar, A. Bianconi, A. S. Biselli, M. Bondi, F. Bossù, Et Al. Jan 2022

Multidimensional, High Precision Measurements Of Beam Single Spin Asymmetries In Semi-Inclusive 𝜋⁺ Electroproduction Off Protons In The Valence Region, S. Diehl, A. Kim, G. Angelini, K. Joo, S. Adhikari, M. J. Amaryan, M. Arratia, H. Atac, H. Avakian, C. Ayerbe Gayoso, N. A. Baltzell, L. Barion, S. Bastami, M. Battaglieri, I. Bedlinskiy, F. Benmokhtar, A. Bianconi, A. S. Biselli, M. Bondi, F. Bossù, Et Al.

Physics Faculty Publications

High precision measurements of the polarized electron beam-spin asymmetry in semi-inclusive deep inelastic scattering (SIDIS) from the proton have been performed using a 10.6 GeV incident electron beam and the CLAS12 spectrometer at Jefferson Lab. We report here a high precision multidimensional study of single π+ SIDIS data over a large kinematic range in Bjorken x, fractional energy, and transverse momentum of the hadron as well as photon virtualities Q2 ranging from 1–7  GeV2. In particular, the structure function ratio FsinϕLU/FUU has been determined, where FsinϕLU is a twist-3 …

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Beam-Spin Asymmetry Σ For Σ⁻ Hyperon Photoproduction Off The Neutron, N. Zachariou, E. Munevar, B. L. Berman, P. Bydžovský, A. Cieplý, G. Feldman, Y. Ilieva, P. Nadel-Turonski, D. Skoupil, A. V. Sarantsev, D. P. Watts B, M. J. Amaryan, G. Angelini, W. R. Armstrong, H. Atac, H. Avakian, L. Barion, M. Bashkanov, M. Battaglieri, I. Bedlinskiy, Et Al. Jan 2022

Beam-Spin Asymmetry Σ For Σ⁻ Hyperon Photoproduction Off The Neutron, N. Zachariou, E. Munevar, B. L. Berman, P. Bydžovský, A. Cieplý, G. Feldman, Y. Ilieva, P. Nadel-Turonski, D. Skoupil, A. V. Sarantsev, D. P. Watts B, M. J. Amaryan, G. Angelini, W. R. Armstrong, H. Atac, H. Avakian, L. Barion, M. Bashkanov, M. Battaglieri, I. Bedlinskiy, Et Al.

Physics Faculty Publications

We report a new measurement of the beam-spin asymmetry, Σ, for the →𝛾n → K+Σ− reaction using quasi-free neutrons in a liquid-deuterium target. The new dataset includes data at previously unmeasured photon energy and angular ranges, thereby providing new constraints on partial wave analyses used to extract properties of the excited nucleon states. The experimental data were obtained using the CEBAF Large Acceptance Spectrometer (CLAS), housed in Hall B of the Thomas Jefferson National Accelerator Facility (JLab). The CLAS detector measured reaction products from a liquid-deuterium target produced by an energy-tagged, linearly polarised photon beam with …

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The Cross-Section Measurement For The 3H (E, E', K+) Nnλ Reaction, K. N. Suzuki, T. Gogami, B. Pandey, Florian Hauenstein, Charles E. Hyde, Z. Ye, J. Zhang, X. Zheng, Et Al. Jan 2022

The Cross-Section Measurement For The 3H (E, E', K+) Nnλ Reaction, K. N. Suzuki, T. Gogami, B. Pandey, Florian Hauenstein, Charles E. Hyde, Z. Ye, J. Zhang, X. Zheng, Et Al.

Physics Faculty Publications

The small binding energy of the hypertriton leads to predictions of the non-existence of bound hypernuclei for isotriplet three-body systems such as nnΛ. However, invariant mass spectroscopy at GSI has reported events that may be interpreted as the bound nnΛ state. The nnΛ state was sought by missing-mass spectroscopy via the (e, e′K+) reaction at Jefferson Lab’s experimental Hall A. The present experiment has higher sensitivity to the nnΛ-state investigation in terms of better precision by a factor of about three. The analysis shown in this article focuses on the derivation of the reaction cross-section for …

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Measurement Of Spin Density Matrix Elements In Λ(1520) Photoproduction At 8.2-8.8 Gev, Shankar Adhikari, C. S. Akondi, M. Albrecht, Moskov Amaryan, Tyler Viducic, B. Zihlmann, Et Al., Gluex Collaboration, D. I. Glazier, V. Mathieu Jan 2022

Measurement Of Spin Density Matrix Elements In Λ(1520) Photoproduction At 8.2-8.8 Gev, Shankar Adhikari, C. S. Akondi, M. Albrecht, Moskov Amaryan, Tyler Viducic, B. Zihlmann, Et Al., Gluex Collaboration, D. I. Glazier, V. Mathieu

Physics Faculty Publications

We report on the measurement of spin density matrix elements of the Λ(1520) in the photoproduction reaction γp→Λ(1520)K+, via its subsequent decay to K−p. The measurement was performed as part of the GlueX experimental program in Hall D at Jefferson Laboratory using a linearly polarized photon beam with Eγ = 8.2 GeV–8.8 GeV. These are the first such measurements in this photon energy range. Results are presented in bins of momentum transfer squared, − (t − t0). We compare the results with a Reggeon exchange model and determine that natural exchange amplitudes are …

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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. Jan 2022

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/Fp2, 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 …

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Neutrino Energy Reconstruction From Semi-Inclusive Samples, R. González-Jiménez, M. B. Barbaro, J. A. Caballero, T. W. Donnelly, N. Jachowicz, G.D. Megias, K. Niewczas, A. Nikolakopoulos, J.W. Van Orden, J. M. Udías Jan 2022

Neutrino Energy Reconstruction From Semi-Inclusive Samples, R. González-Jiménez, M. B. Barbaro, J. A. Caballero, T. W. Donnelly, N. Jachowicz, G.D. Megias, K. Niewczas, A. Nikolakopoulos, J.W. Van Orden, J. M. Udías

Physics Faculty Publications

We study neutrino-nucleus charged-current reactions on finite nuclei for the situation in which an outgoing muon and a proton are detected in coincidence; i.e., we focus on semi-inclusive cross sections. We limit our attention to one-body current interactions (quasielastic scattering) and assess the impact of different nuclear effects in the determination of the neutrino energy. We identify the regions in phase space where the neutrino energy can be reconstructed relatively well and study whether the cross section in those regions is significant. Our results indicate that it is possible to filter more than 50% of all events according to the …

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New Measurements Of The Beam-Normal Single Spin Asymmetry In Elastic Electron Scattering Over A Range Of Spin-0 Nuclei, Prex And Crex Collaborations, D. Adhikari, H. Albataineh, D. Androic, F. Hauenstein, M.N.H. Rashad, W. Zhang, J. Zhang, X. Zheng, Et Al. Jan 2022

New Measurements Of The Beam-Normal Single Spin Asymmetry In Elastic Electron Scattering Over A Range Of Spin-0 Nuclei, Prex And Crex Collaborations, D. Adhikari, H. Albataineh, D. Androic, F. Hauenstein, M.N.H. Rashad, W. Zhang, J. Zhang, X. Zheng, Et Al.

Physics Faculty Publications

We report precision determinations of the beam-normal single spin asymmetries (An) in the elastic scattering of 0.95 and 2.18 GeV electrons off 12C, 40Ca, 48Ca, and 208Pb at very forward angles where the most detailed theoretical calculations have been performed. The first measurements of An for 40Ca and 48Ca are found to be similar to that of 12C, consistent with expectations and thus demonstrating the validity of theoretical calculations for nuclei with Z ≤ 20. We also report An for 208Pb at two …

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Measuring Recoiling Nucleons From The Nucleus With The Future Electron Ion Collider, Florian Hauenstein, A. Jentsch, J. R. Pybus, A. Kiral, M. D. Baker, Y. Furletova, O. Hen, D. W. Higinbotham, Charles Hyde, V. Morozov, D. Romanov, Lawrence B. Weinstein Jan 2022

Measuring Recoiling Nucleons From The Nucleus With The Future Electron Ion Collider, Florian Hauenstein, A. Jentsch, J. R. Pybus, A. Kiral, M. D. Baker, Y. Furletova, O. Hen, D. W. Higinbotham, Charles Hyde, V. Morozov, D. Romanov, Lawrence B. Weinstein

Physics Faculty Publications

Short range correlated nucleon-nucleon (NN) pairs are an important part of the nuclear ground state. They are typically studied by scattering an electron from one nucleon in the pair and detecting its spectator correlated partner (“spectator-nucleon tagging”). The Electron Ion Collider (EIC) should be able to detect these nucleons, since they are boosted to high momentum in the laboratory frame by the momentum of the ion beam. To determine the feasibility of these studies with the planned EIC detector configuration, we have simulated quasielastic scattering for two electron and ion beam energy configurations: 5 GeV e− and 41 …

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Reply To "Comment On 'Quasielastic Lepton Scattering And B=Back-To-Back Nucleons In The Short-Time Approximation' ", S. Pastore, J. Carlson, Rocco Schiavilla, J. L. Barrow, S. Gandolfi, R. B. Wiringa Jan 2022

Reply To "Comment On 'Quasielastic Lepton Scattering And B=Back-To-Back Nucleons In The Short-Time Approximation' ", S. Pastore, J. Carlson, Rocco Schiavilla, J. L. Barrow, S. Gandolfi, R. B. Wiringa

Physics Faculty Publications

We briefly review the concept of scaling and how it occurs in quasielastic electron and neutrino scattering from nuclei, and then the particular approach to scaling in the short-time approximation. We show that, whereas two-nucleon currents do significantly enhance the transverse electromagnetic response, they do not spoil scaling, but, in fact, enhance it. We provide scaling results obtained in the short-time approximation that verify this claim. The enhanced scaling, although obtained empirically, is not “accidental”—as claimed in [O. Benhar, Phys. Rev. C 105, 049801 (2022)]—but rather reflects quasielastic kinematics and the dominant role played by pion-exchange interactions and currents …

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Spectroscopic Study Of A Possible Λ𝑛𝑛 Resonance And A Pair Of (E, E'K⁺) Reaction With A Tritium Target, Hall A Collaboration, B. Pandey, L. Tang, T. Gogami, Florian Hauenstein, Charles Hyde, Z. Ye, J. Zhang, X. Zheng, Et Al. Jan 2022

Spectroscopic Study Of A Possible Λ𝑛𝑛 Resonance And A Pair Of (E, E'K⁺) Reaction With A Tritium Target, Hall A Collaboration, B. Pandey, L. Tang, T. Gogami, Florian Hauenstein, Charles Hyde, Z. Ye, J. Zhang, X. Zheng, Et Al.

Physics Faculty Publications

A mass spectroscopy experiment with a pair of nearly identical high-resolution spectrometers and a tritium target was performed in Hall A at Jefferson Lab. Utilizing the (e,e′K+) reaction, enhancements, which may correspond to a possible Λnn resonance and a pair of ΣNN states, were observed with an energy resolution of about 1.21 MeV (σ), although greater statistics are needed to make definitive identifications. An experimentally measured Λnn state may provide a unique constraint in determining the Λn interaction, for which no scattering data exist. In addition, although bound A = 3 and 4 Σ hypernuclei have …

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Probing For High-Momentum Protons In ⁴He Via The ⁴He (E, E'P) X Reactions, Jefferson Lab Hall A Collaboration, S. Iqbal, F. Benmokhtar, M. Ivanov, L. B. Weinstein, X. Zheng, P. Zhu, R. Zielinski, Et Al Jan 2022

Probing For High-Momentum Protons In ⁴He Via The ⁴He (E, E'P) X Reactions, Jefferson Lab Hall A Collaboration, S. Iqbal, F. Benmokhtar, M. Ivanov, L. B. Weinstein, X. Zheng, P. Zhu, R. Zielinski, Et Al

Physics Faculty Publications

Experimental cross sections for the 4He(e,e′p) X reactions in the missing energy range from 0.017 to 0.022 GeV and up to a missing momentum of 0.632 GeV/c at xB = 1.24 and Q2 = 2 (GeV/c)2 are reported. The data are compared to relativistic distorted-wave impulse approximation calculations for the 4He(e,e′p)3H channel. Significantly more events are observed for pm ≥ 0.45 GeV/c than are predicted by the theoretical model, and striking fluctuations in the ratio of data to the theoretical model around pm = 0.3GeV/c are possible signals of initial-state multinucleon …

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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. Jan 2022

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 𝓍B. 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 𝓍B, while systematically including helicity flip amplitudes. …

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Determination Of The Argon Spectral Function From (E, E'P) Data, Jefferson Lab Hall A Collaboration, L. Jiang, A.M. Ankowski, D. Abrams, Florian Hauenstein, Charles Hyde, S. Wood, Z. Ye, J. Zhang, Et Al. Jan 2022

Determination Of The Argon Spectral Function From (E, E'P) Data, Jefferson Lab Hall A Collaboration, L. Jiang, A.M. Ankowski, D. Abrams, Florian Hauenstein, Charles Hyde, S. Wood, Z. Ye, J. Zhang, Et Al.

Physics Faculty Publications

The E12-14-012 experiment, performed in Jefferson Lab Hall A, has measured the (e,e′p) cross section in parallel kinematics using a natural argon target. Here, we report the full results of the analysis of the data set corresponding to beam energy 2.222 GeV, and spanning the missing momentum and missing energy range 15 ≲ pm ≲ 300  MeV /c and 12 ≲ Em ≲ 80  MeV. The reduced cross section, determined as a function of pm and Em with ≈ 4% accuracy, has been fitted using the results of Monte Carlo simulations involving a model spectral function and …

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Unpolarized And Polarized Gluon Pseudo-Distributions At Short Distances: Forward Case, Ian Balitsky, Wayne Morris, Anatoly Radyushkin Jan 2022

Unpolarized And Polarized Gluon Pseudo-Distributions At Short Distances: Forward Case, Ian Balitsky, Wayne Morris, Anatoly Radyushkin

Physics Faculty Publications

We present the results that are necessary in the ongoing lattice calculations of the unpolarized and polarized gluon parton distribution functions (PDFs) within the pseudo-PDF approach. We give a classification of possible two-gluon correlator functions and identify those that contain the invariant amplitude determining the gluon PDF in the light-cone z2 → 0 limit. One-loop calculations have been performed in the coordinate representation and in an explicitly gauge-invariant form. We made an effort to separate ultraviolet (UV) and infrared (IR) sources of the ln(−z2)-dependence at short distances z2. The UV terms cancel in the reduced …

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Rapidity Evolution Of Tmds With Running Coupling, Ian Balitsky, Giovanni A. Chirilli Jan 2022

Rapidity Evolution Of Tmds With Running Coupling, Ian Balitsky, Giovanni A. Chirilli

Physics Faculty Publications

The scale of a coupling constant for rapidity-only evolution of transverse-momentum dependent (TMD) operators in the Sudakov kinematic region is calculated using the Brodsky-Lepage-Mackenzie optimal scale setting [S. J. Brodsky et al., Phys. Rev. D 28, 228 (1983).]. The effective argument of a coupling constant is halfway in the logarithmical scale between the transverse momentum and energy of TMD distribution. The resulting rapidity-only evolution equation is solved for quark and gluon TMDs.

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Accessing Scattering Amplitudes Using Quantum Computers, Raúl A. Briceño, Marco A. Carrillo, Juan V. Guerrero, Maxwell T. Hansen, Alexandru M. Sturzu Jan 2022

Accessing Scattering Amplitudes Using Quantum Computers, Raúl A. Briceño, Marco A. Carrillo, Juan V. Guerrero, Maxwell T. Hansen, Alexandru M. Sturzu

Physics Faculty Publications

Future quantum computers may serve as a tool to access non-perturbative real-time correlation functions. In this talk, we discuss the prospects of using these to study Compton scattering for arbitrary kinematics. The restriction to a finite-volume spacetime, unavoidable in foreseeable quantum-computer simulations, must be taken into account in the formalism for extracting scattering observables. One approach is to work with a non-zero iϵ-prescription in the Fourier transform to definite momentum and then to estimate an ordered double limit, in which the spacetime volume is sent to infinity before ϵ is sent to 0. For the amplitudes and parameters considered here, …

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Cooling Performance In A Dual Energy Storage Ring Cooler, B. Dhital, Y. S. Derbenev, D. Douglas, G. A. Krafft, H. Zhang, F. Lin, V. S. Morozov, Y. Zhang Jan 2022

Cooling Performance In A Dual Energy Storage Ring Cooler, B. Dhital, Y. S. Derbenev, D. Douglas, G. A. Krafft, H. Zhang, F. Lin, V. S. Morozov, Y. Zhang

Physics Faculty Publications

The longitudinal and transverse emittance growth in hadron beams due to intra-beam scattering (IBS) and other heating sources deteriorate the luminosity in a collider. Hence, a strong hadron beam cooling is required to reduce and preserve the emittance. The cooling of high energy hadron beam is challenging. We propose a dual energy storage ring-based electron cooler that uses an electron beam to extract heat away from hadron beam in the cooler ring while the electron beam is cooled by synchrotron radiation damping in the high energy damping ring. In this paper, we present a design of a dual energy storage …

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Quark Spin-Orbit Correlations In The Proton, M. Engelhardt, J. Green, N. Hasan, T. Izubuchi, C. Kallidonis, S. Krieg, S. Liuti, S. Meinel, J. Negele, A. Pochinsky, A. Rajan, G. Silvi, S. Syritsyn Jan 2022

Quark Spin-Orbit Correlations In The Proton, M. Engelhardt, J. Green, N. Hasan, T. Izubuchi, C. Kallidonis, S. Krieg, S. Liuti, S. Meinel, J. Negele, A. Pochinsky, A. Rajan, G. Silvi, S. Syritsyn

Physics Faculty Publications

Generalized transverse momentum-dependent parton distributions (GTMDs) provide a comprehensive framework for imaging the internal structure of the proton. In particular, by encoding the simultaneous distribution of quark transverse positions and momenta, they allow one to directly access longitudinal quark orbital angular momentum, and, moreover, to correlate it with the quark helicity. The relevant GTMD is evaluated through a lattice calculation of a proton matrix element of a quark bilocal operator (the separation in which is Fourier conjugate to the quark momentum) featuring a momentum transfer (which is Fourier conjugate to the quark position), as well as the Dirac structure appropriate …

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Connecting Matrix Elements To Multi-Hadron Form-Factors, Andrew W. Jackura Jan 2022

Connecting Matrix Elements To Multi-Hadron Form-Factors, Andrew W. Jackura

Physics Faculty Publications

We discuss developments in calculating multi-hadron form-factors and transition processes via lattice QCD. Our primary tools are finite-volume scaling relations, which map spectra and matrix elements to the corresponding multi-hadron infinite-volume amplitudes. We focus on two hadron processes probed by an external current, and provide various checks on the finite-volume formalism in the limiting cases of perturbative interactions and systems forming a bound state. By studying model-independent properties of the infinite-volume amplitudes, we are able to rigorously define form-factors of resonances.

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Improving The Electrostatic Design Of The Jefferson Lab 300 Kv Dc Photogun, S.A.K. Wijethunga, M. A. Mamun, R. Suleiman, C. Hernandez-Garcia, B. Bullard, J. R. Delayen, J. Grames, G. A. Krafft, G. Palacios-Serrano, M. Poelker Jan 2022

Improving The Electrostatic Design Of The Jefferson Lab 300 Kv Dc Photogun, S.A.K. Wijethunga, M. A. Mamun, R. Suleiman, C. Hernandez-Garcia, B. Bullard, J. R. Delayen, J. Grames, G. A. Krafft, G. Palacios-Serrano, M. Poelker

Physics Faculty Publications

The 300 kV DC high voltage photogun at Jefferson Lab was redesigned to deliver electron beams with a much higher bunch charge and improved beam properties. The original design provided only a modest longitudinal electric field (Ez) at the photocathode, which limited the achievable extracted bunch charge. To reach the bunch charge goal of approximately few nC with 75 ps full-width at half-maximum Gaussian laser pulse width, the existing DC high voltage photogun electrodes and anode–cathode gap were modified to increase Ez at the photocathode. In addition, the anode aperture was spatially shifted with respect to the beamline longitudinal axis …

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