Nuclear Commons^™

Beam Spin Asymmetry In Semi-Inclusive Electroproduction Of Hadron Pairs, M. J. Amaryan, M. Hattawy, S. E. Kuhn, Y. Prok, J. Zhang, Z. W. Zhao, Et Al., Clas Collaboration

Physics Faculty Publications

A first measurement of the longitudinal beam spin asymmetry A_LU in the semi-inclusive electroproduction of pairs of charged pions is reported. A_LU is a higher-twist observable and offers the cleanest access to the nucleon twist-3 parton distribution function e(x). Data have been collected in the Hall-B at Jefferson Lab by impinging a 5.498-GeV electron beam on a liquid-hydrogen target, and reconstructing the scattered electron and the pion pair with the CLAS detector. One-dimensional projections of the A^sin_LU^ϕR moments are extracted for the kinematic variables of interest in the valence quark region. The …

Ruling Out Color Transparency In Quasielastic ¹²C(E,E'P) Up To Q² Of 14.2 (Gev/C)², D. Bhetuwal, J. Matter, H. Szumila-Vance, F. Hauenstein, C. Yero, J. Zhang, Et Al., Hall C. Collaboration

Physics Faculty Publications

Quasielastic ¹²C(e,e'p) scattering was measured at spacelike 4-momentum transfer squared Q² = 8, 9.4, 11.4, and 14.2 (GeV/c)², the highest ever achieved to date. Nuclear transparency for this reaction was extracted by comparing the measured yield to that expected from a plane-wave impulse approximation calculation without any final state interactions. The measured transparency was consistent with no Q² dependence, up to proton momenta of 8.5 GeV/c, ruling out the quantum chromodynamics effect of color transparency at the measured Q² scales in exclusive (e, e'p) reactions. These results impose strict constraints on models of color …

Photoproduction Of The F₂(1270) Meson Using The Clas Detector, Krishna P. Adhikari, Moskov J. Amaryan, Dilini Bulumulla, Mohammad Hattawy, G. Gavalian, Charles E. Hyde, Yelena Prok, J. Zhang, Et Al., Clas Collaboration

Physics Faculty Publications

The quark structure of the f₂(1270) meson has, for many years, been assumed to be a pure quark-antiquark (qq⁻) resonance with quantum numbers J^PC = 2⁺⁺. Recently, it was proposed that the f₂(1270) is a molecular state made from the attractive interaction of two 𝜌 mesons. Such a state would be expected to decay strongly to final states with charged pions due to the dominant decay 𝜌 → π⁺π^-, whereas decay to two neutral pions would likely be suppressed. Here, we measure for the first time the reaction 𝛾p …

Differential Cross Sections For Λ (1520) Using Photoproduction At Clas, K. P. Adhikari, M.J. Amaryan, G. Gavalian, M. Hattawy, Y. Prok, Et. Al., The Clas Collaboration

Physics Faculty Publications

The reaction 𝛾p → K+Λ (1520) using photoproduction data from the CLAS g12 experiment at Jefferson Lab is studied. The decay of Λ(1520) into two exclusive channels, Σπ⁺π^- and Σ^-π⁺, is studied from the detected K⁺, π⁺, and π^- particles. A good agreement is established for the Λ(1520) differential cross sections with the previous CLAS measurements. The differential cross sections as a function of center-of-mass angle are extended to higher photon energies. Newly added are the differential cross sections as a function of invariant four-momentum transfer t, …

Experimental Tests Of Qcd Scaling Laws At Large Momentum Transfer In Exclusive Light-Meson Photoproduction, Moskov J. Amaryan, William J. Briscoe, Michael G. Ryskin, Igor I. Strakovsky

Physics Faculty Publications

We evaluated CLAS Collaboration measurements for the 90^◦ meson photoproduction off the nucleon using a tagged photon beam spanning the energy interval s = 3–11 GeV². The results are compared with the “quark counting rules” predictions.

Accurate Determination Of The Neutron Skin Thickness Of 208Pb, D. Adhikari, H. Albataineh, D. Androic, F. Hauenstein, M.N.H. Rashad, W. Zhang, J. Zhang, X. Zheng

Physics Faculty Publications

We report a precision measurement of the parity-violating asymmetry A_pv in the elastic scattering of longitudinally polarized electrons from ²⁰⁸Pb. We measure A_pv = 550 ± 16(stat) ± 8(syst) parts per billion, leading to an extraction of the neutral weak form factor F_w (Q² = 0.00616 GeV²) = 0.368 ± 0.013. Combined with our previous measurement, the extracted neutron skin thickness is R_n - R_p = 0.283 ± 0.071 fm. The result also yields the first significant direct measurement of the interior weak density of ²⁰⁸Pb: ρ⁰_w = …

Consistency Checks For Two-Body Finite-Volume Matrix Elements: Conserved Currents And Bound States, Raúl A. Briceño, Christopher J. Monahan

Physics Faculty Publications

We present a model-independent framework to determine finite-volume corrections of matrix elements of spatially separated current-current operators. We define these matrix elements in terms of Compton-like amplitudes, i.e., amplitudes coupling single-particle states via two current insertions. We show that the infrared behavior of these matrix elements is dominated by the single-particle pole, which is approximated by the elastic form factors of the lowest-lying hadron. Therefore, given lattice data on the relevant elastic form factors, the finite-volume effects can be estimated nonperturbatively and without recourse to effective field theories. For illustration purposes, we investigate the implications of the proposed formalism for …

Measurement Of Deeply Virtual Compton Scattering Off 4He With The Cebaf Large Acceptance Spectrometer At Jefferson Lab, Clas Collaboration, R. Dupré, Mohammad Hattawy, N. A. Batzell, Stephen Bültmann, Bayram Torayev, Moskov Amaryan, Dilini L. Bulumulla, M. Mayer, David C. Payette, Yelena Prok, Jiwan Poudel, Lawrence B. Weinstein, B. Yale, N. Zachariou, J. Zhang, Et Al.

Physics Faculty Publications

We report on the measurement of the beam spin asymmetry in the deeply virtual Compton scattering off ⁴He using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab using a 6 GeV longitudinally polarized electron beam incident on a pressurized ⁴He gaseous target. We detail the method used to ensure the exclusivity of the measured reactions, in particular the upgrade of CLAS with a radial time projection chamber to detect the low-energy recoiling ⁴He nuclei and an inner calorimeter to extend the photon detection acceptance at forward angles. Our results confirm the theoretically predicted enhancement of the …

Towards High-Precision Parton Distributions From Lattice Qcd Via Distillation, Colin Egerer, Robert G. Edwards, Christos Kallidonis, Kostas Orginos, Anatoly V. Radyushkin, David G. Richards, Eloy Romero, Savvas Zafeiropoulos, On Behalf Of The Hadstruc Collaboration

Physics Faculty Publications

We apply the Distillation spatial smearing program to the extraction of the unpolarized isovector valence PDF of the nucleon. The improved volume sampling and control of excited-states afforded by distillation leads to a dramatically improved determination of the requisite Ioffe-time Pseudo-distribution (pITD). The impact of higher-twist effects is subsequently explored by extending the Wilson line length present in our non-local operators to one half the spatial extent of the lattice ensemble considered. The valence PDF is extracted by analyzing both the matched Ioffe-time Distribution (ITD), as well as a direct matching of the pITD to the PDF. Through development of …

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

Physics Faculty Publications

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

¹² C(E,E'Pn) Measurements Of Short Range Correlations In The Tensor-To-Scalar Interaction Transition Region, I. Korover, J. R. Pybus, A. Schmidt, F. Hauenstein, M. Duer, L. B. Weinstein, M. J. Amaryan, D. Bullumulla, M. Hattawy, X. Zheng, Et Al., The Clas Collaboration

Physics Faculty Publications

High-momentum configurations of nucleon pairs at short-distance are probed using measurements of the ¹²C(e,'p) and ¹²C (e,e'pN) reactions (where N is either n or p), at high Q² and 𝒙_B > 1.1. The data span a missing-momentum range of 300-1000 MeV/c and are predominantly sensitive to the transition region of the strong nuclear interaction from a tensor to scalar interaction. The data are well reproduced by theoretical calculations using the generalized contact formalism with both chiral and phenomenological nucleon-nucleon (NN) interaction models. This agreement suggests that the measured high missing-momentum protons up to 1000 MeV/c predominantly …

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

Physics Faculty Publications

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

Deeply Virtual Compton Scattering Off Helium Nuclei With Positron Beams, Sara Fucini, Mohammad Hattawy, Matteo Rinaldi, Segio Scopetta

Physics Faculty Publications

Positron initiated deeply virtual Compton scattering (DVCS) off ⁴He and ³He nuclei is described. The way the so-called d-term could be obtained from the real part of the relevant Compton form factor is summarized, and the importance and novelty of this measurement is discussed. The measurements addressed for ³He targets could be very useful even in a standard unpolarized target setup, measuring beam spin and beam charge asymmetries only. The unpolarized beam charge asymmetries for DVCS off ³He and ⁴He are also estimated, at JLab kinematics and, for ⁴He, also at a configuration typical …

Exploring Fundamental Properties Of ³He Through The ³He(E, E'D) Process In Clas12, D. W. Higinbotham, C. Keppel, J. Maxwell, D. Nguyen, A. S. Tadepalli, H. Szumila-Vance, S. Širca, M. Mihovilovič, A. Denniston, O. Hen, J. Kahlbow, R. Milner, J. R. Pybus, E. P. Segarra, C. Fogler, F. Hauenstein, C. Hyde, L. B. Weinstein, G. Johansson, E. Piasetzky, A. Beck, S. Beck, E. O. Cohen, I. Korover, A. Biselli, A. Schmidt

Physics Faculty Publications

Recent double-polarization measurements of (e,e'p) and (e,e'd) quasi-elastic processes on ³He have revealed deficiencies in our understanding of three-body system. With the limited kinematic coverage of these low-acceptance spectrometer experiments, it has been impossible to disentangle which aspects of the theoretical description are problematic. While resolving these uncertainties is interesting from a pure few-body physics point of view, it is also of critical importance to our interpretation of deep-inelastic data from polarized ³He which is often used as an effective polarized neutron target: as precision has improved over time, small effects like the net proton polarization end up being significant …

Semi-Inclusive Deep Inelastic Scattering Measurements Of A = 3 Nuclei With Clas12 In Hall B, S. Li, R. Cruz Torres, J. Rittenhouse West, F. Yuan, A. Denniston, O. Hen, J. Kahlbow, T. Kutz, J. R. Pybus, E. P. Segarra, C. Ayerbe-Gayoso, H. Bhatt, D. Bhetuwal, T. Chetry, B. Devkota, J. Dunne, D. Dutta, L. El Fassi, T. Gaballah, A. Karki, M. Amarian, C. Fogler, F. Hauenstein, C. Hyde, G. Gavalian, L. B. Weinstein, D. Gaskell, D. W. Higinbotham, C. Keith, C. Keppel, J. Maxwell, A. Tadepalli, D. Meekins, D. Nguyen, S. Stepanyan, H. Szumila-Vance, Z. G. Xiao, Y. Wang, Z. H. Ye, Y. P. Zhang, K. Griffioen, P. Bosted, A. Bianconi, G. Costantini, M. Leali, S. Migliorati, L. Venturelli, V. Mascagna, A Boyer, F. Benmokhtar, A. Gadsby, A. Parker, L. Baashen, B. Raue, W. J. Briscoe, S. Ratliff, A. Schmidt, E. Seroka, P. Sharp, P. G. Solazzo, I. I. Strakovsky, K. Adhikari, G. Niculescu, K.-T. Brinkmann, S. Diehl, A. Kripko, Sheren Alsalmi, Tyler J. Hague, A. Beck, S. Beck, E. Cohen, I. Korover, G. Johansson, C. Neuburger, E. Piasetzky, Michael Nycz, R. Capobianco, T. Haywars, F.-X. Girod, K. Joo, A. Kim, V. Klimenko, R. Santos, U. Shrestha, P. Simmerling, J. Richard, N. Trotta, B. Mckinnon, W. Brooks

Physics Faculty Publications

We propose to measure precision ratios of charged pion electroproduction in Semi-Inclusive Deep Inelastic Scattering from ²D, ³He and ³H targets to test the flavor dependence of the EMC effect in the valence quark region. This trio of targets has been chosen to minimize hadron attenuation effects while maximizing nuclear asymmetry. The standard configuration CLAS12 detector will be used in the experiment to detect scattered electrons and knocked-out pions. A new, dedicated, tritium target that will be developed for the approved quasi-elastic experiment, E12-20-005 [1], will be used. The experiment will measure semi-inclusive production of charged pions over a wide …

Rapid Radiological Analysis Of Building Materials, Askar Safarov, Joseph Sharonov, Ali Mukhamedov, Askarali Azimov, Akmal Safarov, Mukhammad Salimov, B Radzhabboev

Scientific Journal of Samarkand University

Measurements of the dose-forming radionuclide concentrations such as Rа-226, Тh-232 and К-40 were carried out in samples of building materials with different ageing times. The radium equivalent activities of the samples were determined. Possible values of the correcting coefficients to the activity of Ra-226 that take into account the radioactive equilibrium were calculated. This, in turn, allows to perform rapid radiological analysis of building materials.

Parton Distribution Functions From Ioffe Time Pseudodistributions From Lattice Calculations: Approaching The Physical Point, Bálint Joó, Joseph Karpie, Kostas Orginos, Anatoly V. Radyushkin, David G. Richards, Savvas Zafeiropoulos

Physics Faculty Publications

We present results for the unpolarized parton distribution function of the nucleon computed in lattice QCD at the physical pion mass. This is the first study of its kind employing the method of Ioffe time pseudodistributions. Beyond the reconstruction of the Bjorken-x dependence, we also extract the lowest moments of the distribution function using the small Ioffe time expansion of the Ioffe time pseudodistribution. We compare our findings with the pertinent phenomenological determinations.

Measurement Of Pion-Pion Final State Interactions In Η → Π +Π −Γ With Clas At Jefferson Lab, Torri C. Jeske

Physics Theses & Dissertations

Decays of pseudoscalar mesons proceed from the chiral anomaly, which arises from spontaneous chiral symmetry breaking. In the limit of massless quarks (chiral limit), the η → π +π −γ the decay width is determined solely by the box anomaly term in the Wess Zumino Witten Lagrangian. Since the physical quarks are not massless, the decay region of the η meson is far from the chiral limit and thus proper inclusion of the momentum dependence is essential to reproduce the measured decay width. Several theoretical frameworks have been proposed to describe these interactions. We report a new measurement of the …

Deeply Virtual Compton Scattering At Hall A, Jefferson Lab, Mohamed Nuhman Hashir Rashad

Physics Theses & Dissertations

The Standard Model of particle physics defines quarks and leptons as the basic building blocks of all matter. The interaction between them are mediated by force carrying gauge bosons. Quantum ChromoDynamics (QCD), the theory that explains the strong interaction is still not complete enough to derive the physical observables of a Quark-Gluon system from the fundamental degrees of freedom of it’s constituents. Experimentally observable single particle densities provide important insights into our understanding of the quark-gluon system and hence help fill in the gaps of QCD. Generalized Parton Distributions (GPDs) provide simultaneous information of both spacial and longitudinal momentum distributions …

Fast Neutron Assay Of Elemental Content Of Bulk Samples, Calder Emerson Lane

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this research was to analyze the capabilities of fast neutrons in the detection and analysis of various isotopes in bulk samples. The deuterium-tritium (DT) fusion reaction generates highly penetrating, high-energy (14.1-MeV) neutrons which induce nuclear reactions in irradiated targets. Neutrons and gamma rays are generated in these reactions. Emitted gamma rays are characteristic of the emitter; the gamma spectrum enables stoichiometric identification of the assayed samples. Neutron backscattering can also be used for identification of the elemental composition of the sample.

This work had three objectives. The first objective was to develop a computational technique to model …