Elementary Particles and Fields and String Theory Commons^™

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 …

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 …

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 …

Cebaf Injector Model For KL Beam Conditions, Sunil Pokharel, Geoffrey A. Krafft, A. S. Hofler, R. Kazimi, M. Bruker, J. Grames, S. Zhang, Frank Zimmerman (Ed.), Hitoshi Tanaka (Ed.), Porntip Sudmuang (Ed.), Prapawan Sunwong (Ed.), Thakonwat Chanwattana (Ed.), Christine Petit-Jean-Genaz (Ed.), Volker R.W. Schaa (Ed.)

Physics Faculty Publications

The Jefferson Lab KL experiment will run at the Continuous Electron Beam Accelerator Facility with a much lower bunch repetition rate (7.80 or 15.59 MHz) than nominally used (249.5 or 499 MHz). While the proposed average current of 2.5 - 5.0 µA is relatively low compared to the maximum CEBAF current of approximately 180 µA, the corresponding bunch charge is atypically high for CEBAF injector operation. In this work, we investigated the evolution and transmission of low-rep-rate, high-bunch-charge (0.32 to 0.64 pC) beams through the CEBAF injector. Using the commercial software General Particle Tracer, we have simulated and analyzed the …

Inverse Moment Of The B Meson Quasidistribution Amplitude, Ji Xu, Xi-Ruo Zhang, Shuai Zhao

Physics Faculty Publications

We perform a study on the structure of the inverse moment (IM) of quasidistributions, by taking B-meson quasidistribution amplitude (quasi-DA) as an example. Based on a one-loop calculation, we derive the renormalization group equation and velocity evolution equation for the first IM of quasi-DA. We find that, in the large velocity limit, the first IM of B-meson quasi-DA can be factorized into IM as well as logarithmic moments of light-cone distribution amplitude (LCDA), accompanied by short distance coefficients. Our results can be useful either in understanding the patterns of perturbative matching in large momentum effective theory or evaluating inverse …

Beam-Recoil Transferred Polarization In K+Y Electroproduction In The Nucleon Resonance Region With Clas12, D. S. Carman, A. D'Angelo, L. Lanza, V. I. Mokeev, K. P. Adhikari, M. J. Amaryan, W. R. Armstrong, H. Atac, H. Avakian, C. Ayerbe Gayoso, N. A. Baltzell, L. Barion, M. Battaglieri, I. Bedlinskiy, B. Benkel, A. Bianconi, A. S. Biselli, M. Bondi, S. Boiarinov, V. Ziegler

Physics Faculty Publications

Beam-recoil transferred polarizations for the exclusive electroproduction of K + Λ and K + Σ⁰ final states from an unpolarized proton target have been measured using the CLAS12 spectrometer at Jefferson Laboratory. The measurements at beam energies of 6.535 and 7.546 GeV span the range of four-momentum transfer Q² from 0.3 to 4.5 GeV² and invariant energy W from 1.6 to 2.4 GeV, while covering the full center-of-mass angular range of the K⁺. These new data extend the existing hyperon polarization data from CLAS in a similar kinematic range but from a significantly larger dataset. …

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 …

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 …

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 …

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 …

Study Of The Λ/Σ⁰ Electroproduction In The Low-Q² Region At Jlab, K. Okuyama, K. Itabashi, S. Nagao, S. N. Nakamura, K. N. Suzuki, T. Gogami, B. Pandey, L. Tang, D. Abrams, T. Akiyama, D. Androic, K. Aniol, C. Ayerbe Gayoso, J. Bane, S. Barcus, J. Barrow, V. Bellini, H. Bhatt, D. Bhetuwal, D. Biswas, A. Camsonne, J. Castellanos, J.- P. Chen, J. Chen, S. Covrig, D. Chrisman, R. Cruz-Torres, R. Das, E. Fuchey, K. Gnanvo, F. Garibaldi, T. Gautam, J. Gomez, P. Gueye, T. J. Hague, O. Hansen, W. Henry, Florian Hauenstein, D. W. Higinbotham, Charles E. Hyde, M. Kaneta, C. Keppel, T. Kutz, N. Lashley-Colthirst, S. Li, H. Liu, J. Mammei, P. Markowitz, R. E. Mcclellan, F. Meddi, D. Meekins, R. Michaels, M. Mihovilovic, A. Moyer, D. Nguyen, M. Nycz, V. Owen, C. Palatchi, S. Park, T. Petkovic, S. Premathilake, P. E. Reimer, J. Reinhold, S. Riordan, V. Rodriguez, C. Samanta, S. N. Santiesteban, B. Sawatzky, S. Širca, K. Slifer, T. Su, Y. Tian, Y. Toyama, K. Uehara, G. M. Urciuoli, D. Votaw, J. Williamson, B. Wojtsekhowski, S. A. Wood, B. Yale, Z. Ye, J. Zhang, X. Zheng

Physics Faculty Publications

We performed an experiment using tritium and hydrogen cryogenic gas targets at Thomas Jefferson National Accelerator Facility (JLab) in 2018 (E12-17-003)[1, 2]. In this article, we discuss the Λ/Σ⁰ hyperon electroproduction from hydrogen target. Elementary Λ/Σ⁰ hyperon production processes are important not only for an absolute mass scale calibration in our experiment, but also for the study of the electroproduction mechanisms themselves. In this article, we reported the results of the differential cross section for the p(e, e’K⁺)Λ/Σ⁰ reaction at Q² ∼ 0.5 (GeV/c)².

Magnetic Structure Of Few-Nucleon Systems At High Momentum Transfers In A Chiral Effective Field Theory Approach, A. Gnech, R. Schiavilla

Physics Faculty Publications

The five low-energy constants (LECs) in the electromagnetic current derived in chiral effective field theory (χEFT) up to one loop are determined by a simultaneous fit to the A=2−3 nuclei magnetic moments and to the deuteron magnetic form factor and threshold electrodisintegration at backward angles over a wide range of momentum transfers. The resulting parametrization then yields predictions for the ³He/³H magnetic form factors in excellent accord with the experimental values for momentum transfers ranging up to ≈0.8 GeV/c, beyond the expected regime of validity of the χEFT approach. The calculations are based on last-generation two-nucleon interactions …

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 …

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 …

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. …

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 …

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, Frank Zimmerman (Ed.), Porntip Sudmuang (Ed.), Prapong Klysubun (Ed.), Prapaiwan Sunwong (Ed.), Thakonwat Chanwattana (Ed.), Christine Petit-Jean-Genaz (Ed.), Volker R.W. Schaa (Ed.)

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 …

Existence And Non-Existence Of Doubly Heavy Tetraquark Bound States, M. Pflaumer, Luka Leskovec, S. Meinel, M. Wagner

Physics Faculty Publications

In this work we investigate the existence of bound states for doubly heavy tetraquark systems Q¯Q¯′qq′ in a full lattice-QCD computation, where heavy bottom quarks are treated in the framework of non-relativistic QCD. We focus on three systems with quark content b¯b¯ud, b¯b¯us and b¯c¯ud. We show evidence for the existence of b¯b¯ud and b¯b¯us bound states, while no binding appears to be present for b¯c¯ud. For the bound four-quark states we also discuss the importance of various creation operators and give an estimate of the meson-meson and diquark-antidiquark percentages.