Nuclear Commons^™

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 …

Two- And Three-Nucleon Contact Interactions And Ground-State Energies Of Light- And Medium-Mass Nuclei, R. Schiavilla, L. Girlanda, A. Gnech, A. Kievsky, A. Lovato, L. E. Marcucci, M. Piarulli, M. Viviani

Physics Faculty Publications

Classes of two-nucleon (2N) contact interactions are developed in configuration space at leading order (LO), next-to-leading order (NLO), and next-to-next-to-next-to-leading order (N3LO) by fitting the experimental singlet np scattering length and deuteron binding energy at LO, and np and pp scattering data in the laboratory-energy ranges 0–15 MeV at NLO and 0–25 MeV at N3LO. These interactions are regularized by including two Gaussian cutoffs, one for T=0 and the other for T=1 channels. The cutoffs are taken to vary in the ranges R₀=(1.5–2.3) fm and R₁=(1.5–3.0) fm. The 780 (1100) data points up to …

Observation Of Beam Spin Asymmetries In The Process Ep → E'Π⁺Π⁻ X With Clas 12, T. B. Hayward, C. Dilks, A. Vossen, Dilini Bulumulla, Mohammad Hattawy, Florian Hauenstein, Mariana Khachatryan, Sebastian E. Kuhn, Yelena Prok, B. Yale, N. Zachariou, J. Zhang, Et Al., Clas Collaboration

Physics Faculty Publications

The observation of beam spin asymmetries in two-pion production in semi-inclusive deep inelastic scattering off an unpolarized proton target is reported. The data presented here were taken in the fall of 2018 with the CLAS12 spectrometer using a 10.6 GeV longitudinally spin-polarized electron beam delivered by CEBAF at JLab. The measured asymmetries provide the first opportunity to extract the parton distribution function e(x), which provides information about the interaction between gluons and quarks, in a collinear framework that offers cleaner access than previous measurements. The asymmetries also constitute the first ever signal sensitive to the helicity-dependent two-pion fragmentation function …

Solving Relativistic Three-Body Integral Equations In The Presence Of Bound States, Andrew W. Jackura, Raúl A. Briceño, Sebastian M. Dawid, Md. Habib E. Islam, Connor Mccarty

Physics Faculty Publications

We present a simple scheme for solving relativistic integral equations for the partial-wave projected three-body amplitudes. Our techniques are used to solve a problem of three scalar particles with a formation of a S-wave two-body bound state. We rewrite the problem in a form suitable for numerical solution and then explore three solving strategies. In particular, we discuss different ways of incorporating the bound-state pole contribution in the integral equations. All of them lead to agreement with previous results obtained using finite-volume spectra of the same theory, providing further evidence of the validity of the existing finite- and infinite-volume formalism …

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 …

Constraining 1 + 𝒥 → 2 Coupled-Channel Amplitudes In A Finite Volume, Raúl A. Briceño, Jozef J. Dudek, Luka Leskovec

Physics Faculty Publications

Whether one is interested in accessing the excited spectrum of hadrons or testing the standard model of particle physics, electroweak transition processes involving multihadron channels in the final state play an important role in a variety of experiments. Presently the primary theoretical tool with which one can study such reactions is lattice QCD, which is defined in a finite spacetime volume. In this work, we investigate the feasibility of implementing existing finite-volume formalism in realistic lattice QCD calculation of reactions in which a stable hadron can transition to one of several two-hadron channels under the action of an external current. …

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 …

P-Wave Nucleon-Pion Scattering Amplitude In The Δ(1232) Channel From Lattice Qcd, Giorgio Silvi, Srijit Paul, Constantia Alexandrou, Stefan Krieg, Luka Leskovec, Stefan Meinel, John Negele, Marcus Petschlies, Andrew Pochinsky, Gumaro Rendon, Sergey Syritsyn, Antonio Todaro

Physics Faculty Publications

We determine the Δ(1232) resonance parameters using lattice QCD and the Lüscher method. The resonance occurs in elastic pion-nucleon scattering with J^P = 3/2⁺ in the isospin I=3/2, P-wave channel. Our calculation is performed with N_f = 2+1 flavors of clover fermions on a lattice with L ≈ 2.8 fm. The pion and nucleon masses are m_π = 255.4 (1.6) MeV and mN = 1073(5) MeV, respectively, and the strong decay channel Δ → _πN is found to be above the threshold. To thoroughly map out the energy dependence of the nucleon-pion …

Improved Λp Elastic Scattering Cross Sections Between 0.9 And 2.0 Gev/C As A Main Ingredient Of The Neutron Star Equation Of State, J. Rowley, N. Compton, C. Djalali, Krishna P. Adhikari, Dilini L. Bulumulla, Mohammad Hattawy, Sebastian E. Kuhn, Pushpa Pandey, Yelena Prok, M. Yurov, J. Zhang, Z. W. Zhao, Et Al., Clas Collaboration

Physics Faculty Publications

Strange matter is believed to exist in the cores of neutron stars based on simple kinematics. If this is true, then hyperon-nucleon interactions will play a significant part in the neutron star equation of state. Yet, compared to other elastic scattering processes, there is very little data on Λ-N scattering. This experiment utilized the CEBAF Large Acceptance Spectrometer (CLAS) detector to study the Λp→Λp elastic scattering cross section in the incident Λ momentum range 0.9-2.0  GeV/c. These are the first data on this reaction since the 1970s. The new cross sections have significantly better accuracy and precision than the existing …

Analyzing The Effect Of Second-Class Currents On Neutron Beta Decay Observables And The Effect Of Thomas Rotation On The Relativistic Transformations Of Electromagnetic Fields, Lakshya Malhotra

Theses and Dissertations--Physics and Astronomy

The next generation of neutron beta decay measurements will attempt to analyze various beta decay observables of up to O(10^-4) precision. At this level of experimental precision, the effects of second-class currents will contribute theoretical uncertainties to the interpretation of these measurements. Therefore, it is important to investigate the effects of these second-class currents on decay parameters, such as the Fierz interference term b which is linear in beyond standard model couplings. A maximum likelihood statistical framework and Rfit techniques are employed to study these second-class currents effects. Inputs to the Rfit technique are obtained through …

Effective Field Theory Applications: From Dark Matter To Neutrino Nucleon Scattering, Qing Chen

Theses and Dissertations--Physics and Astronomy

Weakly-interacting-massive-particles (WIMPs) are a large class of viable dark matter candidates. We compute cross sections for electroweak-doublet WIMPs scattering on atomic nuclei, at leading and subleading order using heavy WIMP effective field theory. Neutrino-nucleon charged current elastic scattering is an important process in the detectors of long baseline accelerator neutrino oscillation experiments. We compute QED radiative corrections to this process employing soft-collinear effective field theory.

Equations Of State For Warm Dense Carbon From Quantum Espresso, Derek J. Schauss

Theses and Dissertations

Warm dense plasma is the matter that exists, roughly, in the range of 10,000 to 10,000,000 Kelvin and has solid-like densities, typically between 0.1 and 10 grams per centimeter. Warm dense fluids like hydrogen, helium, and carbon are believed to make up the interiors of many planets, white dwarfs, and other stars in our universe. The existence of warm dense matter (WDM) on Earth, however, is very rare, as it can only be created with high-energy sources like a nuclear explosion. In such an event, theoretical and computational models that accurately predict the response of certain materials are thus very …

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.

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 …

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 …

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 …

A Study Of 26al(P, Γ)27si With The Silicon Array For Branching Ratio Experiments (Sabre), Erin Courtney Good

LSU Doctoral Dissertations

The observation of the radioisotope ²⁶Al is an indicator of ongoing nucleosynthesis in the Galaxy due to its short lifetime (t_1/2 = 7.2 × 10⁵ yr) on Galactic timescales. It is thought to be synthesized in several different environments in our Galaxy, one of which is in classical novae. Classical novae are stellar explosions that occur on the surface of a white dwarf in a binary system with a main sequence star. The isotopic production resulting from the nucleosynthesis that drives these explosions can be modeled with the input of nuclear reaction rates. In recent years, many …

Simulation And Development Of The Radial Time Projection Chamber For The Bonus12 Experiment In Clas12, Nathan M. Dzbenski

Physics Theses & Dissertations

Knowledge of the structure of nucleons (i:e: protons and neutrons) is a central topic of interest to nuclear/particle physicists. Much more is known about the structure of the proton than the neutron due to the lack of high-density free neutron targets. The Barely Off-shell Nucleon Structure experiment (BONuS12) at Jefferson Lab (JLab) is a second generation experiment upgraded/optimized to advance our knowledge of the neutron's structure using the deep-inelastic scattering of electrons off deuterium. Typically, since deuterium is a nuclear target, corrections for off-shell and nuclear binding effects must be taken into account in order to extract results on the …

Single-Neutron Transfer To 50ti, Jessica Nebel-Crosson

Physics and Astronomy Summer Fellows

This is a continuation of the data analysis of a neutron-transfer reaction with ⁵⁰Ti, in which the data was collected in 2019 and this analysis focuses on automating the calibration and peak fits for the generated spectra. Future work will continue with producing angular distributions for the rest of the excitation states and further analyzation in order to draw conclusions about single-neutron state structures.

Eusectra: European Nuclear Security Training Centre Providing Hands-On Training And Education In Nuclear Security And Safeguards, Willem Janssens, Veronique Berthou, Abbas Kamel, Jean Galy, Klaus Luetzenkirchen, Klaus Mayer, Stefan Nonneman

International Journal of Nuclear Security

The European Nuclear Security Training Centre (EUSECTRA) inaugurated under this global name about 10 years ago and operated by the European Commission Joint Research Centre (JRC), located both on the Karlsruhe (Germany) and Ispra (Italy) sites, includes a large variety of capacity building and professional development activities which span from the hands-on training for nuclear security and safeguards actors (e.g. respectively border guards or customs and nuclear inspectors) to educational efforts in both nuclear security and safeguards. Whereas the first ones, which gave rise to the new name, focus mainly on detection, on-site assistance, crime-scene management, technical reach-back and nuclear …

Physical Protection System, Corrective Actions, And Weaknesses Identification Based On Nuclear Security Series: The Hypothetical Atomic Research Institute (Hari) Case, Ouadie Kabach

International Journal of Nuclear Security

The paper is an attempt, based on the IAEA’s Nuclear Security Series (NSS), to identify any unacceptable dysfunction of Physical Protection System (PPS) of the Material Test Reactor (MTR) facility in a Hypothetical Atomic Research Institute (HARI). The evaluation of an existing or a proposed PPS requires a methodical approach whereby the ability of the security system to meet defined protection goals as the safeguard against possibility of sabotage and theft should be measured. Without such kind of careful assessment, the PPS might waste valuable resources on unnecessary protection or, worse yet, fail to provide adequate protection at critical points …

Investigation Of Finite Temperature And Continuum Effects On Nuclear Excitations, Herlik Wibowo

Dissertations

The low-energy nuclear response at finite-temperature significantly affects the radiative neutron capture reaction rates of the r-process nucleosynthesis. In order to address this topic, the first part of this study focuses on the response of compound nuclei or nuclei at finite temperature. The thermal nuclear response satisfies the Bethe-Salpeter equation (BSE) with the static and dynamical kernels of different origins. While the origin of the static kernel is the nearly instantaneous nucleon-meson interaction, the dynamical kernel is induced by the coupling between nucleons and phonons. The presence of singularities in the dynamical kernel makes the BSE unsolvable, however, a time …

Small-X Qcd Calculations With A Biased Ensemble, Gary Kapilevich

Dissertations, Theses, and Capstone Projects

In this dissertation, I will argue that we can study functional fluctuations in unintegrated gluon distributions, in the MV model as well as JIMWLK, using reweighting techniques, which will allow me to calculate QCD observables with "biased ensembles". This technique will enable me to study rare functional configurations of the gluon distributions, that might have been selected for in, for example, the centrality criteria used by the ATLAS and ALICE collaborations. After a review of these techniques, as well as a review of QCD physics at high energy in general, I will use biased ensembles to compute observables in two …