Elementary Particles and Fields and String Theory Commons^™

Cebaf Injector Model For KL Beam Conditions, Sunil Pokharel, Geoffrey A. Krafft, A. S. Hofler, R. Kazimi, M. Bruker, J. Grames, S. Zhang

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 …

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.

Combining Nonperturbative Transverse Momentum Dependence With Tmd Evolution, J.O. Gonzalez-Hernandez, T. C. Rogers, N. Sato

Physics Faculty Publications

Central to understanding the nonperturbative, intrinsic partonic nature of hadron structure are the concepts of transverse momentum dependent (TMD) parton distribution and fragmentation functions. A TMD factorization approach to the phenomenology of semi-inclusive processes that includes evolution, higher orders, and matching to larger transverse momentum is ultimately necessary for reliably connecting with phenomenologically extracted nonperturbative structures, especially when widely different scales are involved. In this paper, we will address some of the difficulties that arise when phenomenological techniques that were originally designed for very high energy applications are extended to studies of hadron structures, and we will solidify the connection …

Perturbative Unitarity And Nec Violation In Genesis Cosmology, Yong Cai, Ji Xu, Shuai Zhao, Siyi Zhou

Physics Faculty Publications

Explorations of the violation of null energy condition (NEC) in cosmology could enrich our understanding of the very early universe and the related gravity theories. Although a fully stable NEC violation can be realized in the “beyond Horndeski” theory, it remains an open question whether a violation of the NEC is allowed by some fundamental properties of UV-complete theories or the consistency requirements of effective field theory (EFT). We investigate the tree-level perturbative unitarity for stable NEC violations in the contexts of both Galileon and “beyond Horndeski” genesis cosmology, in which the universe is asymptotically Minkowskian in the past. We …

Study Of ⋀N Fsi With ⋀ Quasi-Free Productions On The ³H (E, E'K⁺) X Reaction At Jlab, K. Itabashi, K. N. Suzuki, B. Pandey, K. Okuyama, T. Gogami, S. Nagao, S. N. Nakamura, 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, F. Hauenstein, D. W. Higinbotham, C. 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. Milhovilovic, 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

An nnΛ is a neutral baryon system with no charge. The study of the pure Λ-neutron system such as nnΛ gives us information on the Λn interaction. The nnΛ search experiment (E12-17-003) was performed at JLab Hall A in 2018. In this article, the Λn FSI was investigated by a shape analysis of the ³H(e, e′K⁺)X missing mass spectrum, and a preliminary result for the Λn FSI study is given.

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 …

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.

𝒯, 𝒫-Odd Effects In The Luoh⁺ Cation, Daniel E. Maison, Leonid V. Skripnikov, Gleb Penyazkov, Matt Grau, Alexander N. Petrov

Physics Faculty Publications

The LuOH⁺ cation is a promising system to search for manifestations of time reversal and spatial parity violation effects. Such effects in LuOH⁺ induced by the electron electric dipole moment eEDM and the scalar-pseudoscalar interaction of the nucleus with electrons, characterized by k_s constant, in LuOH⁺ are studied. The enhancement factors, polarization in the external electric field, hyperfine interaction, and rovibrational structure are calculated. The study is required for the experiment preparation and extraction of the eEDM and k_s values from experimental data.

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 …

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 …

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 …

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).

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 …

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 …

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 …

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. …

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 …

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 …

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 …