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Old Dominion University

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Articles 121 - 150 of 434

Full-Text Articles in Elementary Particles and Fields and String Theory

Drell-Yan Angular Lepton Distributions At Small X From Tmd Factorization, Ian Balitsky Jan 2021

Drell-Yan Angular Lepton Distributions At Small X From Tmd Factorization, Ian Balitsky

Physics Faculty Publications

The Drell-Yan process is studied in the framework of TMD factorization in the Sudakov region s » Q2 » q2⊥ corresponding to recent LHC experiments with Q2 of order of mass of Z-boson and transverse momentum of DY pair ∼ few tens GeV. The DY hadronic tensors are expressed in terms of quark and quark-gluon TMDs with 1Q2 and 1Nc2 accuracy. It is demonstrated that in the leading order in Nc the higher-twist quark-quark-gluon TMDs reduce to leading-twist TMDs due to QCD equation of motion. The resulting hadronic tensors depend on …

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Intense Monochromatic Photons Above 100 Kev From An Inverse Compton Source, Kirsten Deitrick, Georg H. Hoffstaetter, Carl Franck, Bruno D. Muratori, Peter H. Williams, Geoffrey A, Krafft, Balša Terzić, Joe Crone, Hywel Owen Jan 2021

Intense Monochromatic Photons Above 100 Kev From An Inverse Compton Source, Kirsten Deitrick, Georg H. Hoffstaetter, Carl Franck, Bruno D. Muratori, Peter H. Williams, Geoffrey A, Krafft, Balša Terzić, Joe Crone, Hywel Owen

Physics Faculty Publications

Quasimonochromatic x rays are difficult to produce above 100 keV, but have a number of uses in x-ray and nuclear science, particularly in the analysis of transuranic species. Inverse Compton scattering (ICS) is capable of fulfilling this need, producing photon beams with properties and energies well beyond the limits of typical synchrotron radiation facilities. We present the design and predicted output of such an ICS source at CBETA, a multiturn energy-recovery linac with a top energy of 150 MeV, which we anticipate producing x rays with energies above 400 keV and a collimated flux greater than 108 photons per second …

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One-Loop Structure Of Parton Distribution For The Gluon Condensate And "Zero Modes", Anatoly Radyushkin, Shuai Zhao Jan 2021

One-Loop Structure Of Parton Distribution For The Gluon Condensate And "Zero Modes", Anatoly Radyushkin, Shuai Zhao

Physics Faculty Publications

We present results for one-loop corrections to the recently introduced “gluon condensate” PDF F(x). In particular, we give expression for the gg-part of 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 PDF F(x). However a q2δ(x) term was found for the ξ = 0 GPD F(x, q2) at nonzero momentum transfer q. Overall, our results do not agree with the original attempt …

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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 Jan 2021

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 …

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Constraining 1 + 𝒥 → 2 Coupled-Channel Amplitudes In A Finite Volume, Raúl A. Briceño, Jozef J. Dudek, Luka Leskovec Jan 2021

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. …

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Laser Chirping In Inverse Compton Sources At High Electron Beam Energies And High Laser Intensities, Balŝa Terzić, Jeffrey Mckaig, Erik Johnson, Tabin Dharanikota, Geoffrey A. Krafft Jan 2021

Laser Chirping In Inverse Compton Sources At High Electron Beam Energies And High Laser Intensities, Balŝa Terzić, Jeffrey Mckaig, Erik Johnson, Tabin Dharanikota, Geoffrey A. Krafft

Physics Faculty Publications

The onset of nonlinear effects, such as ponderomotive broadening, increases the radiation bandwidth and thereby places a stringent limitation on the laser intensity used in inverse Compton sources. Recently, we have shown that a judicious longitudinal laser frequency modulation ("chirping") can perfectly compensate for this ponderomotive broadening and restore the narrow band property of scattered radiation in the Thomson regime, when electron recoil during the collision with the laser can be neglected. Consequently, using QED, the laser chirping has been extended to the Compton regime, where electron recoil is properly accounted for. Here we present a new, semiclassical model for …

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Simultaneous Monte Carlo Analysis Of Parton Densities And Fragmentation Functions, Eric Moffat, W. Melnitchouk, Ted C. Rogers, N. Sato, Jefferson Lab Angular Momentum Collaboration Jan 2021

Simultaneous Monte Carlo Analysis Of Parton Densities And Fragmentation Functions, Eric Moffat, W. Melnitchouk, Ted C. Rogers, N. Sato, Jefferson Lab Angular Momentum Collaboration

Physics Faculty Publications

We perform a comprehensive new Monte Carlo analysis of high-energy lepton-lepton, lepton-hadron and hadron-hadron scattering data to simultaneously determine parton distribution functions (PDFs) in the proton and parton to hadron fragmentation functions (FFs). The analysis includes all available semi-inclusive deep-inelastic scattering and single-inclusive e+e− annihilation data for pions, kaons and unidentified charged hadrons, which allows the flavor dependence of the fragmentation functions to be constrained. Employing a new multistep fitting strategy and more flexible parametrizations for both PDFs and FFs, we assess the impact of different datasets on sea quark densities and confirm the previously observed suppression …

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The Continuum And Leading Twist Limits Of Parton Distribution Functions In Lattice Qcd, Joseph Karpie, Kostas Orginos, Anatoly Radyushkin, Savvas Zafeiropoulos, For The Hadstruc Collaboration Jan 2021

The Continuum And Leading Twist Limits Of Parton Distribution Functions In Lattice Qcd, Joseph Karpie, Kostas Orginos, Anatoly Radyushkin, Savvas Zafeiropoulos, For The Hadstruc Collaboration

Physics Faculty Publications

In this study, we present continuum limit results for the unpolarized parton distribution function of the nucleon computed in lattice QCD. This study is the first continuum limit using the pseudo-PDF approach with Short Distance Factorization for factorizing lattice QCD calculable matrix elements. Our findings are also compared with the pertinent phenomenological determinations. Inter alia, we are employing the summation Generalized Eigenvalue Problem (sGEVP) technique in order to optimize our control over the excited state contamination which can be one of the most serious systematic errors in this type of calculations. A crucial novel ingredient of our analysis is the …

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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 Jan 2021

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 …

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Magnetic Field Sensors For Detection Of Trapped Flux In Superconducting Radio Frequency Cavities, Ishwari Prasad Parajuli, Gianluigi Ciovati, Jean R. Delayen Jan 2021

Magnetic Field Sensors For Detection Of Trapped Flux In Superconducting Radio Frequency Cavities, Ishwari Prasad Parajuli, Gianluigi Ciovati, Jean R. Delayen

Physics Faculty Publications

Superconducting radio frequency (SRF) cavities are fundamental building blocks of modern particle accelerators. They operate at liquid helium temperatures (2–4 K) to achieve very high quality factors (1010–1011). Trapping of magnetic flux within the superconductor is a significant contribution to the residual RF losses, which limit the achievable quality factor. Suitable diagnostic tools are in high demand to understand the mechanisms of flux trapping in technical superconductors, and the fundamental components of such diagnostic tools are magnetic field sensors. We have studied the performance of commercially available Hall probes, anisotropic magnetoresistive sensors, and flux-gate magnetometers with …

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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 Jan 2021

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 JP = 3/2+ in the isospin I=3/2, P-wave channel. Our calculation is performed with Nf = 2+1 flavors of clover fermions on a lattice with L ≈ 2.8 fm. The pion and nucleon masses are mπ = 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 …

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Inclusive Electron Scattering And The Genie Neutrino Event Generator, A. Papadopoulou, A. Ashkenazi, S. Gardiner, M. Betancourt, S. Dytman, L. B. Weinstein, E. Piasetzky, F. Hauenstein, M. Khachatryan, S. Dolan, G. D. Megias, O. Hen Jan 2021

Inclusive Electron Scattering And The Genie Neutrino Event Generator, A. Papadopoulou, A. Ashkenazi, S. Gardiner, M. Betancourt, S. Dytman, L. B. Weinstein, E. Piasetzky, F. Hauenstein, M. Khachatryan, S. Dolan, G. D. Megias, O. Hen

Physics Faculty Publications

The extraction of neutrino mixing parameters from accelerator-based neutrino-oscillation experiments relies on proper modeling of neutrino-nucleus scattering processes using neutrino interaction event generators. Experimental tests of these generators are difficult due to the broad range of neutrino energies produced in accelerator-based beams and the low statistics of current experiments. Here we overcome these difficulties by exploiting the similarity of neutrino and electron interactions with nuclei to test neutrino event generators using high-precision inclusive electron-scattering data. To this end, we revised the electron-scattering mode of the genie event generator (e-GENIE) to include electron-nucleus bremsstrahlung radiation effects and to use, …

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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 Jan 2021

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 …

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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 Jan 2021

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 …

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Evaluation Of Anisotropic Magnetoresistive (Amr) Sensors For A Magnetic Field Scanning System For Srf Cavities, Ishwari P. Parajuli, Gianluigi Ciovati, Jean R. Delayen, Alex V. Gurevich Jan 2021

Evaluation Of Anisotropic Magnetoresistive (Amr) Sensors For A Magnetic Field Scanning System For Srf Cavities, Ishwari P. Parajuli, Gianluigi Ciovati, Jean R. Delayen, Alex V. Gurevich

Physics Faculty Publications

One of the significant causes of residual losses in superconducting radio-frequency (SRF) cavities is trapped magnetic flux. The flux trapping mechanism depends on many factors that include cool-down conditions, surface preparation techniques, and ambient magnetic field orientation. Suitable diagnostic tools are not yet available to quantitatively correlate such factors’ effect on the flux trapping mechanism. A magnetic field scanning system (MFSS) consisting of AMR sensors, fluxgate magnetometers, or Hall probes is recently commissioned to scan the local magnetic field of trapped vortices around 1.3 GHz single-cell SRF cavities. In this contribution, we will present results from sensitivity calibration and the …

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Measurement Of Pion-Pion Final State Interactions In Η → Π +Π −Γ With Clas At Jefferson Lab, Torri C. Jeske Dec 2020

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 …

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Deeply Virtual Compton Scattering At Hall A, Jefferson Lab, Mohamed Nuhman Hashir Rashad Dec 2020

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 …

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Simulation And Development Of The Radial Time Projection Chamber For The Bonus12 Experiment In Clas12, Nathan M. Dzbenski Aug 2020

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 …

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Consistency Checks For Two-Body Finite-Volume Matrix Elements. Ii. Perturbative Systems, Raúl A. Briceño, Maxwell T. Hansen, Andrew W. Jackura May 2020

Consistency Checks For Two-Body Finite-Volume Matrix Elements. Ii. Perturbative Systems, Raúl A. Briceño, Maxwell T. Hansen, Andrew W. Jackura

Physics Faculty Publications

Using the general formalism presented in [Phys. Rev. D 94, 013008 (2016); Phys. Rev. D 100, 034511 (2019)], we study the finite-volume effects for the 2 þ J → 2 matrix element of an external current coupled to a two-particle state of identical scalars with perturbative interactions. Working in a finite cubic volume with periodicity L, we derive a 1=L expansion of the matrix element through O(1=L5) and find that it is governed by two universal current-dependent parameters, the scalar charge and the threshold two particle form factor. We confirm the result through a numerical study of the …

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The Clas12 Software Framework And Event Reconstruction, V. Ziegler, N. A. Baltzell, F. Bossù, D. S. Carman, P. Chatanon, M. Contalbrigo, J. Newton, M. Ungaro Apr 2020

The Clas12 Software Framework And Event Reconstruction, V. Ziegler, N. A. Baltzell, F. Bossù, D. S. Carman, P. Chatanon, M. Contalbrigo, J. Newton, M. Ungaro

Physics Faculty Publications

We describe offline event reconstruction for the CEBAF Large Acceptance Spectrometer at 12 GeV (CLAS12), including an overview of the offline reconstruction framework and software tools, a description of the algorithms developed for the individual detector subsystems, and the overall approach for charged and neutral particle identification. We also present the scheme for data processing and the code management procedures.

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Heavy Quark Expansion For Heavy-Light Light-Cone Operators, Shuai Zhao Apr 2020

Heavy Quark Expansion For Heavy-Light Light-Cone Operators, Shuai Zhao

Physics Faculty Publications

We generalize the celebrated heavy quark expansion to nonlocal QCD operators. By taking nonlocal heavy-light current on the light-cone as an example, we confirm that the collinear singularities are common between QCD operator and the corresponding operator in heavy quark effective theory (HQET), at the leading power of 1/M expansion. Based on a perturbative calculation in operator form at one-loop level, a factorization formula linking QCD and HQET operators is investigated and the matching coefficient is determined. The matching between QCD and HQET light-cone distribution amplitudes (LCDAs) as well as other momentum distributions of hadron can be derived as …

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Measurement Of The Photon Beam Asymmetry In Γp → K+Σ0 At EΓ = 8.5 Gev With Gluex, Nilanga Indrajie Wickramaarachchi Apr 2020

Measurement Of The Photon Beam Asymmetry In Γp → K+Σ0 At EΓ = 8.5 Gev With Gluex, Nilanga Indrajie Wickramaarachchi

Physics Theses & Dissertations

In this work the photon beam asymmetry Σ for the reaction γp K+ Σ0(1193) is measured using the GlueX experiment in Hall D at Jefferson Lab. The analysis used data that were collected using a linearly polarized photon beam in the energy range (8.2 - 8.8) GeV incident on a liquid hydrogen target. The beam asymmetries are measured as a function of the Mandelstam variable t and as a single value for the low u region. These are the first exclusive measurements of the photon beam asymmetry Σ in this reaction at energies above the baryon resonance …

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High-Luminosity Large Hadron Collider (Hl-Lhc): Technical Design Report, O. Aberle, C. Adorisio, A. Adraktas, M. Ady, J. Albertone, L. Alberty, M. Alcaide Leon, A. Alekou, D. Alesini, B. Almeida Ferreira, P. Alvarez-Lopez, G. Ambrosio, P. Andreu Munoz, M. Anerella, D. Angal-Kalinin, F. Antoniou, G. Apollinari, A. Apollonio, R. Appleby, I. Béjar Alonso, Jean Delayen, I. Zurbano Fernandez, Et Al., I. Béjar Alonso (Ed.), O. Brüning (Ed.), P. Fessia (Ed.), M. Lamont (Ed.), L. Rossi (Ed.), L. Tavian (Ed.), M. Zerlauth (Ed.) Jan 2020

High-Luminosity Large Hadron Collider (Hl-Lhc): Technical Design Report, O. Aberle, C. Adorisio, A. Adraktas, M. Ady, J. Albertone, L. Alberty, M. Alcaide Leon, A. Alekou, D. Alesini, B. Almeida Ferreira, P. Alvarez-Lopez, G. Ambrosio, P. Andreu Munoz, M. Anerella, D. Angal-Kalinin, F. Antoniou, G. Apollinari, A. Apollonio, R. Appleby, I. Béjar Alonso, Jean Delayen, I. Zurbano Fernandez, Et Al., I. Béjar Alonso (Ed.), O. Brüning (Ed.), P. Fessia (Ed.), M. Lamont (Ed.), L. Rossi (Ed.), L. Tavian (Ed.), M. Zerlauth (Ed.)

Physics Faculty Publications

The Large Hadron Collider (LHC) is one of the largest scientific instruments ever built. Since opening up a new energy frontier for exploration in 2010, it has gathered a global user community of about 9000 scientists working in fundamental particle physics and the physics of hadronic matter at extreme temperature and density. To sustain and extend its discovery potential, the LHC will need a major upgrade in the 2020s. This will increase its instantaneous luminosity (rate of collisions) by a factor of five beyond the original design value and the integrated luminosity (total number of collisions) by a factor ten. …

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Long-Range Electroweak Amplitudes Of Single Hadrons From Euclidean Finite-Volume Correlation Functions, Raúl A. Briceño, Zohreh Davoudi, Maxwell T. Hansen, Matthias R. Schindler, Alessandro Baroni Jan 2020

Long-Range Electroweak Amplitudes Of Single Hadrons From Euclidean Finite-Volume Correlation Functions, Raúl A. Briceño, Zohreh Davoudi, Maxwell T. Hansen, Matthias R. Schindler, Alessandro Baroni

Physics Faculty Publications

A relation is presented between single-hadron long-range matrix elements defined in a finite Euclidean spacetime and the corresponding infinite-volume Minkowski amplitudes. This relation is valid in the kinematic region where any number of two-hadron states can simultaneously go on shell, so that the effects of strongly coupled intermediate channels are included. These channels can consist of nonidentical particles with arbitrary intrinsic spins. The result accommodates general Lorentz structures as well as nonzero momentum transfer for the two external currents inserted between the single-hadron states. The formalism, therefore, generalizes the work by Christ et al. [Phys. Rev. D 91, 114510 …

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Measurement Of The Single-Spin Asymmetry A⁰ʸ In Quasi-Elastic ³He↑(E,E'N) Scattering At 0.4 < Q2 < 1.0 Gev/C2, E. Long, Y.W. Zhang, M. Mihovilovic, M. Canan, S. Golge, L. Zhu Jan 2020

Measurement Of The Single-Spin Asymmetry A⁰ʸ In Quasi-Elastic ³He↑(E,E'N) Scattering At 0.4 < Q2 < 1.0 Gev/C2, E. Long, Y.W. Zhang, M. Mihovilovic, M. Canan, S. Golge, L. Zhu

Physics Faculty Publications

Due to the lack of free neutron targets, studies of the structure of the neutron are typically made by scattering electrons from either ²H or ³He targets. In order to extract useful neutron information from a ³He target, one must understand how the neutron in a ³He system differs from a free neutron by taking into account nuclear effects such as final state interactions and meson exchange currents. The target single spin asymmetry A⁰ʸ is an ideal probe of such effects, as any deviation from zero indicates effects beyond plane wave impulse approximation. New measurements of the target single spin …

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First Measurement Of Direct Photoproduction Of The A2(1320)⁰ Meson On The Proton, K.P. Adhikari, M. J. Amaryan, D. Bullumulla, F. Hauenstein, M. Khachatryan, Y. Prok, Et Al., Clas Collaboration Jan 2020

First Measurement Of Direct Photoproduction Of The A2(1320)⁰ Meson On The Proton, K.P. Adhikari, M. J. Amaryan, D. Bullumulla, F. Hauenstein, M. Khachatryan, Y. Prok, Et Al., Clas Collaboration

Physics Faculty Publications

We present the first measurement of the reaction 𝛾p -> a₂(1320)⁰ p in the photon energy range 3.5-5.5 GeV and four-momentum transfer squared 0.2 < -t < 2.0 GeV2. Data were collected with the CEBAF Large Acceptance Spectrometer detector at the Thomas Jefferson National Accelerator Facility. The a2resonance was detected by measuring the reaction 𝛾p → π0ηp and reconstructing the π0η invariant mass. The most prominent feature of the differential cross section is a dip at -t ≈ 0.55 GeV2. This can be described in the framework of Regge phenomenology, where the exchange degeneracy hypothesis …

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Probing The Deuteron At Very Large Internal Momenta, C. Yero, D. Abrams, Z Ahmed, F. Hauenstein, S.A. Wood, J. Zhang, Et Al., Hall C. Collaboration Jan 2020

Probing The Deuteron At Very Large Internal Momenta, C. Yero, D. Abrams, Z Ahmed, F. Hauenstein, S.A. Wood, J. Zhang, Et Al., Hall C. Collaboration

Physics Faculty Publications

We measure 2H(e,e′p)n cross sections at 4-momentum transfers of Q2 = 4.5 ± 0.5   (GeV/c)2 over a range of neutron recoil momenta pr, reaching up to ∼1.0  GeV/c. We obtain data at fixed neutron recoil angles θnq = 35°, 45°, and 75° with respect to the 3-momentum transfer →q. The new data agree well with previous data, which reached pr ∼ 500  MeV/c. At θnq = 35° and 45°, final state interactions, meson exchange currents, and isobar currents are suppressed and the plane wave impulse approximation provides the dominant cross section contribution. …

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Quasielastic Lepton Scattering And Back-To-Back Nucleons In The Short-Time Approximation, S. Pastore, J. Carlson, S. Gandolfi, R. Schiavilla, R. B. Wiringa Jan 2020

Quasielastic Lepton Scattering And Back-To-Back Nucleons In The Short-Time Approximation, S. Pastore, J. Carlson, S. Gandolfi, R. Schiavilla, R. B. Wiringa

Physics Faculty Publications

Understanding quasielastic electron and neutrino scattering from nuclei has taken on new urgency with current and planned neutrino oscillation experiments, and with electron scattering experiments measuring specific final states, such as those involving nucleon pairs in "back-to-back" configurations. Accurate many-body methods are available for calculating the response of light (A <= 12) nuclei to electromagnetic and weak probes, but they are computationally intensive and only applicable to the inclusive response. In the present work we introduce a novel approach, based on realistic models of nuclear interactions and currents, to evaluate the short-time (high-energy) inclusive and exclusive response of nuclei. The approach accounts reliably for crucial two-nucleon dynamics, including correlations and currents, and provides information on back-to-back nucleons observed in electron and neutrino scattering experiments. We demonstrate that in the quasielastic regime and at moderate momentum transfers both initial- and final-state correlations and two-nucleon currents are important for a quantitatively successful description of the inclusive response and final-state nucleons. Finally, the approach can be extended to include relativistic-kinematical and dynamical-effects, at least approximately in the two-nucleon sector, and to describe the response in the resonance-excitation region.

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Gluon Pseudo-Distributions At Short Distances: Forward Case, Ian Balitsky, Wayne Morris, Anatoly Radyushkin Jan 2020

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 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 Ioffe-time distribution (ITD), …

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Developing A High Resolution Zdc For The Eic, J. H. Lee, T. Sako, K. Tanida, M. Murray, Q. Wang, N. Nickel, Y. Yamazaki, Y. Itow, H. Menjo, T. Shibata, C. E. Hyde, V. Baturin, Y. Goto, I. Nakagawa, R. Seidl, K. Kawade, A. Deshpande, B. Schmookler, K. Nakano, T. Chujo, Y. Miyachi Jan 2020

Developing A High Resolution Zdc For The Eic, J. H. Lee, T. Sako, K. Tanida, M. Murray, Q. Wang, N. Nickel, Y. Yamazaki, Y. Itow, H. Menjo, T. Shibata, C. E. Hyde, V. Baturin, Y. Goto, I. Nakagawa, R. Seidl, K. Kawade, A. Deshpande, B. Schmookler, K. Nakano, T. Chujo, Y. Miyachi

Physics Faculty Publications

The Electron Ion Collider offers the opportunity to make un-paralleled multidimen- sional measurements of the spin structure of the proton and nuclei, as well as a study of the onset of partonic saturation at small Bjorken-x [1]. An important requirement of the physics program is the tagging of spectator neutrons and the identification of forward photons. We propose to design and build a Zero Degree Calorimeter, or ZDC, to measure photons and neutrons with excellent energy & position resolution.

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