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

Physics Faculty Publications

No abstract provided.

Solutions For Fermi Questions, January 2022: Question 1: Snow Volume; Question 2: Longbow Arrow Velocity, Larry Weinstein

Physics Faculty Publications

No abstract provided.

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 …

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 …

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 …

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 …

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 …

Nonlinear Meissner Effect In Nb3Sn Coplanar Resonators, Junki Makita, C. Sundahl, Gianluigi Ciovati, C. B. Eom, Alex Gurevich

Physics Faculty Publications

We investigated the nonlinear Meissner effect (NLME) in Nb₃Sn thin-film coplanar resonators by measuring the resonance frequency as a function of a parallel magnetic field at different temperatures. We used low rf power probing in films thinner than the London penetration depth λ(B) to significantly increase the field onset of vortex penetration and measure the NLME under equilibrium conditions. Contrary to the conventional quadratic increase of λ(B) with B expected in s-wave superconductors, we observed a nearly linear increase of the penetration depth with B. We concluded that this behavior of λ(B) is due to weak linked grain …

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).

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 G_μα(z)G̃_λβ(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 …

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 F^sinϕ_LU/F_UU has been determined, where F^sinϕ_LU is a twist-3 …

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 …

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 …

Polarized Structure Function ΣLt' From 𝜋⁰P Electroproduction Data In The Resonance Region At 0.2 Gev² < Q² < 1.0 Gev², E. L. Isupov, V. D. Burkert, A. A. Golubenko, K. Joo, N. S. Markov, V. I. Mokeev, L. C. Smith, N. Zachariou, W. R. Armstrong, H. Atac, Et Al

Physics Faculty Publications

The first results on the σ_LT′ structure function in exclusive π⁰p electroproduction at invariant masses of the final state of 1.5GeV < W < 1.8 GeV and in the range of photon virtualities 0.4 GeV² < Q² < 1.0 GeV² were obtained from data on beam spin asymmetries and differential cross sections measured with the CLAS detector at Jefferson Lab. The Legendre moments determined from the σ_LT′ structure function have demonstrated sensitivity to the contributions from the nucleon resonances in the second and third resonance regions. These new data on the beam spin asymmetries in π⁰p electroproduction extend the opportunities for the extraction of the nucleon resonance electro-excitation amplitudes in …

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 E_γ = 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 …

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 …

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. …

Form Factors And Two-Photon Exchange In High-Energy Elastic Electron-Proton Scattering, M. E. Christy, T. Gautam, L. Ou, S.L. Allison, D. Bulumulla, F. Hauenstein, C. Hyde, K. Park, M.N.H. Rashad, J. Zhang, Y. X. Zhao, P. Zhu, Et Al.

Physics Faculty Publications

We present new precision measurements of the elastic electron-proton scattering cross section for momentum transfer (Q²) up to 15.75  (GeV/c)². Combined with existing data, these provide an improved extraction of the proton magnetic form factor at high Q² and double the range over which a longitudinal or transverse separation of the cross section can be performed. The difference between our results and polarization data agrees with that observed at lower Q² and attributed to hard two-photon exchange (TPE) effects, extending to 8 (GeV/c)² the range of Q² for which a discrepancy …

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 (A_n) 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 A_n 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 A_n for ²⁰⁸Pb at two …

Search For Photoproduction Of Axionlike Particles At Gluex, Shankar Adhikari, C.S. Akondi, M. Albrecht, Moskov Amaryan, Tyler P. Viducic, Z. Zhang, Z. Zhao, J. Zhou, The Gluex Collaboration, Et Al.

Physics Faculty Publications

We present a search for axionlike particles, a, produced in photon-proton collisions at a center-of-mass energy of approximately 4 GeV, focusing on the scenario where the a-gluon coupling is dominant. The search uses a → γγ and a → π⁺π⁻π⁰ decays, and a data sample corresponding to an integrated luminosity of 168  pb⁻¹ collected with the GlueX detector. The search for a → γγ decays is performed in the mass range of 180 < m_a <480  MeV, while the search for a → π⁺π⁻π⁰ decays explores the 600 < m_{a …}

Positivity And Renormalization Of Parton Densities, John Collins, Ted C. Rogers, Nobuo Sato

Physics Faculty Publications

There have been recent debates about whether MS parton densities exactly obey positivity bounds (including the Soffer bound) and whether the bounds should be applied as a constraint on global fits to parton densities and on nonperturbative calculations. A recent paper [Candido et al., Can MS parton distributions be negative?, J. High Energy Phys. 11 (2020) 129] appears to provide a proof of positivity in contradiction with earlier work by other authors. We examine their derivation and find that its primary failure is in the apparently uncontroversial statement that bare parton density (or distribution) function (pdfs) are always …

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 …

Emittance In Nonlinear Thomson Scattering, Erik Johnson, Elizabeth Breen, Geoffrey A. Krafft, Balša Terzić

Physics Faculty Publications

Inverse Compton scattering sources are finding increasing use as intense sources of high-energy photons. When operated at high field strength, ponderomotive detuning of the scattered emission can lead to decreased source performance. Up to now, the calculations of spectra for such nonlinear Thomson scattering have been done assuming a perfectly aligned electron interacts with the incident laser beam and several authors have investigated whether pondermotive detuning may be mitigated or cured by suitable incident laser chirping prescriptions. In order to determine if these chirping prescriptions are suitable in real beams with nonzero emittance, it is necessary to include misaligned boundary …

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 …

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 …

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 x_B = 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 p_m ≥ 0.45 GeV/c than are predicted by the theoretical model, and striking fluctuations in the ratio of data to the theoretical model around p_m = 0.3GeV/c are possible signals of initial-state multinucleon …

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. …

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 p_m and E_m with ≈ 4% accuracy, has been fitted using the results of Monte Carlo simulations involving a model spectral function and …

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 …

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.