Nuclear Commons^™

Searching For Heavy Photons With Detached Vertices In The Heavy Photon Search Experiment, Holly Szumila-Vance

Physics Theses & Dissertations

The Jefferson Lab Heavy Photon Search (HPS) experiment is searching for a hypothetical massive particle called the heavy photon which could mediate a dark electromagnetic-type force. If heavy photons kinetically mix with Standard Model photons, they may be radiated by electrons scattering from a heavy nucleus and then decay to e+e- pairs. HPS uniquely searches for heavy photons that either decay at the target or a measurable distance after. The experiment utilizes a silicon vertex tracker (SVT) for momentum and vertex reconstruction, together with an electromagnetic calorimeter for measuring particle energies and triggering events. The HPS experiment took its first …

R&D Of A High-Performance Dirc Detector For A Future Electron-Ion Collider, Stacey Lee Allison

Physics Theses & Dissertations

An Electron-Ion Collider (EIC) is proposed as the next big scientific facility to be built in the United States, costing over $1 billion in design and construction. Each detector concept for the electron/ion beam interaction point is integrated into a large solenoidal magnet. The necessity for excellent hadronic particle identification (pion/kaon/proton) in the barrel region of the solenoid has pushed research and development (R&D) towards a new, high-performance Detection of Internally Reflected Cherenkov light (DIRC) detector design. The passage of a high energy charged particle through a fused silica bar of the DIRC generates optical Cherenkov radiation. A large fraction …

Lifetime Measurements Of Low-Spin Negative-Parity Levels In 160Gd, S. R. Lesher, C. Casarella, L. M. Robledo, Benjamin P. Crider, R. Ikeyama, I. R. Marsh, Marcus T. Mcellistrem, Erin E. Peters, Francisco M. Prados-Estévez, M. K. Smith, Z. R. Tully, J. R. Vanhoy, Steven W. Yates

Physics and Astronomy Faculty Publications

¹⁶⁰Gd(n,n′γ) experiments were performed with accelerator-produced monoenergetic neutrons. Excitation functions at neutron energies from 1.5 to 2.8 MeV aided in the placement of γ rays in the level scheme and angular distributions at three neutron energies resulted in the determination of 28 excited-level lifetimes or limits in ¹⁶⁰Gd, including the lifetimes of several negative-parity levels attributed to octupole vibrations.

Neutron Scattering Cross Section Measurements For 56Fe, Anthony Paul D. Ramirez, J. Vanhoy, S. F. Hicks, Marcus T. Mcellistrem, Erin E. Peters, Sharmistha Mukhopadhyay, T. D. Harrison, T. J. Howard, D. T. Jackson, P. D. Lenzen, T. D. Nguyen, R. L. Pecha, B. G. Rice, B. K. Thompson, Steven W. Yates

Chemistry Faculty Publications

Elastic and inelastic differential cross sections for neutron scattering from ⁵⁶Fe have been measured for several incident energies from 1.30 to 7.96 MeV at the University of Kentucky Accelerator Laboratory. Scattered neutrons were detected using a C₆D₆ liquid scintillation detector using pulse-shape discrimination and time-of-flight techniques. The deduced cross sections have been compared with previously reported data, predictions from evaluation databases ENDF, JENDL, and JEFF, and theoretical calculations performed using different optical model potentials using the TALYS and EMPIRE nuclear reaction codes. The coupled-channel calculations based on the vibrational and soft-rotor models are found to describe …

Measurement Of Two-Photon Exchange Effect By Comparing Elastic E±P Cross Sections, P. Rimal, D. Adikaram, B. A. Raue, L. B. Weinstein, J. Arrington, W. K. Brooks, M. Ungaro, K. P. Adhikari, A. V. Afanasev, Z. Akbar, S. Anefalos Pereira, R. A. Badui, J. Ball, N. A. Baltzell, M. Battaglieri, V. Batourine, I. Bedlinskiy, A. S. Biselli, S. Boiarinov, W. J. Briscoe, S. Bültmann, V. D. Burkert, D. S. Carman, A. Celentano, T. Chetry, G. Ciullo, L. Clark, L. Colaneri, P. L. Cole, N. Compton, Wesley P. Gohn

Physics and Astronomy Faculty Publications

Background: The electromagnetic form factors of the proton measured by unpolarized and polarized electron scattering experiments show a significant disagreement that grows with the squared four-momentum transfer (Q²). Calculations have shown that the two measurements can be largely reconciled by accounting for the contributions of two-photon exchange (TPE). TPE effects are not typically included in the standard set of radiative corrections since theoretical calculations of the TPE effects are highly model dependent, and, until recently, no direct evidence of significant TPE effects has been observed.

Purpose: We measured the ratio of positron-proton to electron-proton elastic-scattering cross sections …

Working With Cuore In Search For The Neutrinoless-Double Beta Decay, Kevin H. Phung

Physics

The neutrino, if found to be its own anti-particle, will reshape the Standard Model of physics. This paper will give some background information regarding CUORE’s experiment to discover the radioactive process known as neutrinoless double-beta decay, how their experiment works, and my own involvement in their research during the installation phase of the project in the summer of 2017.

Rosenbluth Separation Of The Π0 Electroproduction Cross Section Off The Neutron, M. Mazouz, Z. Ahmed, H. Albataineh, K. Allada, K. A. Aniol, V. Bellini, M. Benali, W. Boeglin, P. Bertin, M. Canan, C. E. Hyde, S. Koirala, M. N. H. Rashad

Physics Faculty Publications

We report the first longitudinal-transverse separation of the deeply virtual exclusive π⁰ electroproduction cross section off the neutron and coherent deuteron. The corresponding four structure functions dσ_L/dt, dσ_T/dt, dσ_LT/dt, and dσ_TT/dt are extracted as a function of the momentum transfer to the recoil system at Q² = 1.75 GeV² and x_B = 0.36. The ed -> edπ⁰ cross sections are found compatible with the small values expected from theoretical models. The en -> enπ⁰ cross sections show a dominance from the response to transversely polarized …

Measurement Of D0 Azimuthal Anisotropy At Midrapidity In Au + Au Collisions At √SNn = 200 Gev, L. Adamczyk, James K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, N. N. Ajitanand, I. Alekseev, D. M. Anderson, R. Aoyama, A. Aparin, D. Arkhipkin, E. C. Aschenauer, M. U. Ashraf, A. Attri, G. S. Averichev, X. Bai, V. Bairathi, A. Behera, R. Bellwied, A. Bhasin, A. K. Bhati, P. Bhattarai, J. Bielcik, J. Bielcikova, L. C. Bland, I. G. Bordyuzhin, J. Bouchet, J. D. Brandenburg, A. V. Brandin, D. Brown, Renee H. Fatemi, Suvarna Ramachandran

Physics and Astronomy Faculty Publications

We report the first measurement of the elliptic anisotropy (v²) of the charm meson D0 at midrapidity (|y| < 1) in Au+Au collisions at √s_NN = 200  GeV. The measurement was conducted by the STAR experiment at RHIC utilizing a new high-resolution silicon tracker. The measured D⁰ v₂ in 0%–80% centrality Au + Au collisions can be described by a viscous hydrodynamic calculation for a transverse momentum (p_T) of less than 4  GeV/c. The D⁰ v₂ as a function of transverse kinetic energy (m_T − m₀, where m …

The Chiral Magnetic Effect In Heavy Ion Collisions From Hydrodynamic Simulations, Elias Lilleskov

Macalester Journal of Physics and Astronomy

The quark-gluon plasma created in heavy ion collisions is an exotic state of matter in which many unusual phenomena are manifested. One such phenomenon is the "Chiral-Magnetic Effect" (CME), wherein the powerful magnetic fields generated by colliding ions spin-polarize chiral quarks, causing a net transport effect in the direction of the fields. The CME predicts specific charge-dependent correlation observables, for which experimental evidence was reported, although the evidence is subject to background contamination. Isobaric collision experiments have been planned for 2018 at RHIC, which will study this effect by comparing 96Ru-96Ru and 96Zr-96Zr collisions. The two colliding systems are expected …

A Study Of Anti-Muon-Neutrino Induced Resonance Production In Nomad Three-Track Topology, Edward Dunton

Senior Theses

In this study we are attempting to measure the sensitivity of our methods to anti-muon neutrino induced resonance interactions in the 3-track topology of the NOMAD experiment. We will use a set of Monte Carlo data meant to resemble the NOMAD outputs but with true event type known and then proceed by using a system of single-variable cuts and multivariable analysis through a multilayer perception neural network to distinguish events from these interactions and events from other neutrino or non-neutrino interactions. We will then produce a measurement of the sensitivity to these interactions and determine whether or not proceeding with …

Resonances Of 25,26f Atomic Nuclei, Matthew Tuttle-Timm

Celebration of Learning

The structure of very unstable atomic nuclides are still not completely understood. The unstable atomic nuclides in this study emit a neutron, which requires determining the energy of decay to better understand the structure. The energy of decay may be calculated from the energy and momentum of the remaining charged fragment and neutron. From the calculated decay energy, information about an isotope’s nuclear structure can be found. At the National Superconducting Cyclotron Laboratory experiment, a ²⁷Ne ion beam hit a liquid deuterium target that resulted in many produced atomic nuclides. One of the isotopes produced was unstable ²⁶F, …

What Are The Low-Q And Large-X Boundaries Of Collinear Qcd Factorization Theorems?, E. Moffat, W. Melnitchouk, T. C. Rogers, N. Sato

Physics Faculty Publications

Familiar factorized descriptions of classic QCD processes such as deeply inelastic scattering (DIS) apply in the limit of very large hard scales, much larger than nonperturbative mass scales and other nonperturbative physical properties like intrinsic transverse momentum. Since many interesting DIS studies occur at kinematic regions where the hard scale, Q ∼ 1-2 GeV, is not very much greater than the hadron masses involved, and the Bjorken scaling variable x_bj is large, x_bj ≳ 0.5, it is important to examine the boundaries of the most basic factorization assumptions and assess whether improved starting points are needed. Using an …

Target And Double Spin Asymmetries Of Deeply Virtual Π0 Production With A Longitudinally Polarized Proton Target And Clas, A. Kim, H. Avakian, V. Burkert, K. Joo, W. Kim, K. P. Adhikari, Z. Akbar, S. Anefalos Pereira, R. A. Badui, M. Battaglieri, S. Bültmann, A. Klein, S E. Kuhn, Y. Prok, B. Torayev, L. B. Weinstein, J. Zhang

Physics Faculty Publications

The target and double spin asymmetries of the exclusive pseudoscalar channel e→p→→epπ⁰ were measured for the first time in the deep-inelastic regime using a longitudinally polarized 5.9 GeV electron beam and a longitudinally polarized proton target at Jefferson Lab with the CEBAF Large Acceptance Spectrometer (CLAS). The data were collected over a large kinematic phase space and divided into 110 four-dimensional bins of Q^2, x_B, −t and ϕ. Large values of asymmetry moments clearly indicate a substantial contribution to the polarized structure functions from transverse virtual photon amplitudes. The interpretation of experimental data in terms of …

Fast Neutron Detection In Nuclear Material Photofission Assay Using A 15 Mev Linear Electron Accelerator, Matthew Steven Hodges

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this research was to use a 15 MeV (K15 model by Varian) linear electron accelerator (linac) for the photon assay of special nuclear materials (SNM). First, the properties of the photon radiation probe were determined. The stochastic radiation transport code, MCNP5, was used to develop computational models for the linac. The spectral distribution of photons as well as dose rate contour maps of the UNLV accelerator facility were computed for several linac operating configurations. These computational models were validated through comparison with experimental measurements of dose rates.

The linac model was used to simulate the photon interrogation …

Synthesis, Characterization And Biological Studies Of Technetium-99m And Rhenium-188 Peptides, Vanessa Anne Sanders

UNLV Theses, Dissertations, Professional Papers, and Capstones

Radiopharmaceuticals are very powerful diagnostic tools for evaluation of a host of medical conditions. These drugs are labeled with radioactive isotopes, which are utilized to create pictures of areas of interest through absorption of the drug. They are currently in high demand due to their ability to image areas that traditional imaging devices cannot. The radioisotope 99mTc, with a half-life of 6.01 hours and a 140 keV gamma emission, is central to many radiopharmaceutical compounds. This isotope is easily obtained from a 99Mo-99mTc generator, through beta decay and column chromatography separations. Very little technetium, less than 6 ng, is needed …

Measurement Of The Cross Section And Longitudinal Double-Spin Asymmetry For Dijet Production In Polarized Pp Collisions At √S = 200 Gev, L. Adamczyk, James K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, N. N. Ajitanand, I. Alekseev, D. M. Anderson, R. Aoyama, A. Aparin, D. Arkhipkin, E. C. Aschenauer, M. U. Ashraf, A. Attri, G. S. Averichev, X. Bai, V. Bairathi, K. Barish, A. Behera, R. Bellwied, A. Bhasin, A. K. Bhati, P. Bhattarai, J. Bielcik, J. Bielcikova, L. C. Bland, I. G. Bordyuzhin, J. Bouchet, J. D. Brandenburg, A. V. Brandin, Renee H. Fatemi, Suvarna Ramachandran

Physics and Astronomy Faculty Publications

We report the first measurement of the longitudinal double-spin asymmetry A_LL for midrapidity dijet production in polarized pp collisions at a center-of-mass energy of √s = 200  GeV. The dijet cross section was measured and is shown to be consistent with next-to-leading order (NLO) perturbative QCD predictions. A_LL results are presented for two distinct topologies, defined by the jet pseudorapidities, and are compared to predictions from several recent NLO global analyses. The measured asymmetries, the first such correlation measurements, support those analyses that find positive gluon polarization at the level of roughly 0.2 over the region of …

Neutron-Unbound Excited States Of 23n, M. Jones, T. Baumann, J. Brett, J. Bullaro, P. A. Deyoung, J.E. Finck, N. Frank, K. Hammerton, J. Hinnefeld, Z. Kohley, A. N. Kuchera, J. Pereira, A. Rabeh, J. K. Smith, A. Spyrou, Sharon L. Stephenson, K. Stiefel, M. Tuttle-Timm, R. G.T. Zegers, M. Thoennessen

Physics and Astronomy Faculty Publications

Neutron unbound states in 23N were populated via proton knockout from an 83.4 MeV/nucleon 24O beam on a liquid deuterium target. The two-body decay energy displays two peaks at E1∼100keV and E2∼1MeV with respect to the neutron separation energy. The data are consistent with shell model calculations predicting resonances at excitation energies of ∼3.6MeV and ∼4.5MeV. The selectivity of the reaction implies that these states correspond to the first and second 3/2− states. The energy of the first state is about 1.3 MeV lower than the first excited 2+ in 24O. This decrease is largely due to coupling with the …

Factorization Breaking Of Adt For Polarized Deuteron Targets In A Relativistic Framework, Sabine Jeschonnek, J. W. Van Orden

Physics Faculty Publications

We discuss the possible factorization of the tensor asymmetry AdT measured for polarized deuteron targets within a relativistic framework. We define a reduced asymmetry and find that factorization holds only in plane wave impulse approximation and if p waves are neglected. Our numerical results show a strong factorization breaking once final state interactions are included. We also compare the d-wave content of the wave functions with the size of the factored, reduced asymmetry and find that there is no systematic relationship of this quantity to the d-wave probability of the various wave functions.

Lorentz-Symmetry Test At Planck-Scale Suppression With Nucleons In A Spin-Polarized 133 Cs Cold Atom Clock, H. Pihan-Le Bars, C. Guerlin, R.-D. Lasseri, J.-P. Ebran, Q. G. Bailey, S. Bize, E. Khan, P. Wolf

Publications

The authors introduce an improved model that links the frequency of the 133 Cs hyperfine Zeeman transitions.

Photoproduction And Radiative Decay Of Ηt Meson In Clas At Jlab, Georgie Mbianda Njencheu

Physics Theses & Dissertations

In this work the η/ meson photoproduction cross sections as well as the distribution of the di-pion invariant mass, m(π+π−), in the radiative decay mode η/ → π+π−γ have been measured using the CLAS detector at the Thomas Jefferson National Accelerator Facility using tagged incident photons in the center-of-mass energy range 1.96 GeV - 2.72 GeV. The measurements are performed on a liquid hydrogen target in the reaction γp → pη/(η/ → π+π−γ). The analysis is based on the …

Collective Quadrupole Behavior In 106Pd, Francisco M. Prados-Estévez, Erin E. Peters, A. Chakraborty, M. G. Mynk, D. Bandyopadhyay, N. Boukharouba, S. N. Choudry, Benjamin P. Crider, P. E. Garrett, S. F. Hicks, A. Kumar, S. R. Lesher, C. J. Mckay, Marcus T. Mcellistrem, Sharmistha Mukhopadhyay, J. N. Orce, M. Scheck, J. R. Vanhoy, J. L. Wood, Steven W. Yates

Chemistry Faculty Publications

Excited states in ¹⁰⁶Pd were studied with the (n,n′γ) reaction, and comprehensive information for excitations with spin ≤6ℏ was obtained. The data include level lifetimes in the femtosecond regime, spins and parities, transition multipolarities, and multipole mixing ratios, which allow the determination of reduced transition probabilities. The E2 decay strength to the low-lying states is mapped up to ≈2.4 MeV in excitation energy. The structures associated with quadrupole collectivity are elucidated and organized into bands.

Lifetimes In 124Te: Examining Critical-Point Symmetry In The Te Nuclei, S. F. Hicks, J. R. Vanhoy, P. G. Burkett, B. R. Champine, S. J. Etzkorn, P. E. Garrett, Steven W. Yates, Minfang Yeh

Physics and Astronomy Faculty Publications

The Doppler-shift attenuation method following inelastic neutron scattering was used to determine the lifetimes of nuclear levels to 3.3-MeV excitation in ¹²⁴Te. Level energies and spins, γ-ray energies and branching ratios, and multipole-mixing ratios were deduced from measured γ-ray angular distributions at incident neutron energies of 2.40 and 3.30 MeV, γ-ray excitation functions, and γγ coincidence measurements. The newly obtained reduced transition probabilities and level energies for ¹²⁴Te were compared to critical-point symmetry model predictions. The E(5) and β⁴ potential critical-point symmetries were also investigated in ¹²²Te and ¹²⁶Te.

First Measurement Of Unpolarized Semi-Inclusive Deep-Inelastic Scattering Cross Sections From A 3He Target, X. Yan, K. Allada, K. Aniol, J. R. M. Annand, T. Averett, F. Benmokhtar, W. Bertozzi, P. C. Bradshaw, P. Bosted, A. Camsonne, M. Canan, G. D. Cates, C. Chen, J. -P. Chen, W. Chen, K. Chirapatpimol, E. Chudakov, E. Cisbani, J. C. Cornejo, F. Cusanno, M. M. Dalton, W. Deconinck, C. W. De Jager, R. De Leo, X. Deng, A. Deur, H. Ding, P. A. M. Dolph, C. Dutta, D. Dutta, A. Kolarkar, Wolfgang Korsch

Physics and Astronomy Faculty Publications

The unpolarized semi-inclusive deep-inelastic scattering (SIDIS) differential cross sections in ³He(e,e′π^±)X have been measured for the first time in Jefferson Lab experiment E06-010 with a 5.9 GeV e⁻ beam on a ³He gas target. The experiment focuses on the valence quark region, covering a kinematic range 0.12 < x_bj < 0.45, 1 < Q² < 4 (GeV/c)², 0.45 < z_h < 0.65, and 0.05 < P_t < 0.55 GeV/c. The extracted SIDIS differential cross sections of π^± production are compared with existing phenomenological models while the ³He nucleus approximated as two protons and one …

Characterization Of Neutron And Proton Exposure On The Radiation Resistant Bacterium, Deinococcus Radiodurans, Ronald C. Lenker

Theses and Dissertations

Deinococcus radiodurans is a robust bacterium that is known for its extraordinary resistance to ionizing radiation. In general, many of the investigations of this bacterium's resistance have revolved around low linear energy transfer radiation, such as gamma and electron radiation. This study explored Deinococcus radiodurans's ability to survive high linear energy transfer radiation, specifically proton and neutron radiation. Deinococcus radiodurans was dehydrated to reduce the effects of low linear energy transfer radiation. The bacteria were exposed to both neutron and proton radiation of varying amounts and rehydrated. The resulting colonies were counted and compared to colonies of non-irradiated control samples …

Modeling The White Sands Missile Range Fast Burst Reactor Using A Discrete Ordinates Code, Pentran, Taylor R. Schulmeister

Theses and Dissertations

The goal of this research was to develop and characterize a deterministic model of a fast burst reactor (FBR) using a discrete ordinates neutral particle transport code, PENTRAN. The White Sands Missile Range FBR design was chosen for this research because this FBR is important to the DoD due to its short duration, high energy neutron flux which is representative of the neutron flux output created by a nuclear weapon. One, two, and three dimensional PENTRAN models of the FBR were developed and neutron transport based eigenvalue calculations were performed. These eigenvalue calculations were conducted using two different set of …

Target And Beam-Target Spin Asymmetries In Exclusive Pion Electroproduction For Q2 > 1 Gev2. Ii. Ep → Eπ0P, P. E. Bosted, A. Kim, K. P. Adhikari, D. Adikaram, Z. Akbar, M. J. Amaryan, S. Anefalos Pereira, H. Avakian, R. A. Badui, J. Ball, I. Balossino, M. Battaglieri, I. Bedlinskiy, A. S. Biselli, S. Boiarinov, W. J. Briscoe, W. K. Brooks, S. Bültmann, V. D. Burkert, T. Cao, D. S. Carman, A. Celentano, S. Chandavar, G. Charles, T. Chetry, G. Ciullo, L. Clark, L. Colaneri, P. L. Cole, M. Contalbrigo, Wesley P. Gohn

Physics and Astronomy Faculty Publications

Beam-target double-spin asymmetries and target single-spin asymmetries were measured for the exclusive π⁰ electroproduction reaction γ^∗p → pπ⁰, expanding an analysis of the γ^∗p → nπ⁺ reaction from the same experiment. The results were obtained from scattering of 6-GeV longitudinally polarized electrons off longitudinally polarized protons using the CEBAF Large Acceptance Spectrometer at Jefferson Laboratory. The kinematic ranges covered are 1.1 < W < 3 GeV and 1 < Q² < 6 GeV². Results were obtained for about 5700 bins in W, Q², cos(θ^∗), and ϕ^∗. The beam-target asymmetries were found …

Elliptic Flow Of Electrons From Heavy-Flavor Hadron Decays In Au + Au Collisions At √SNn = 200, 62.4, And 39 Gev, L. Adamczyk, J. Kevin Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, N. N. Ajitanand, I. Alekseev, D. M. Anderson, R. Aoyama, A. Aparin, D. Arkhipkin, E. C. Aschenauer, M. U. Ashraf, A. Attri, G. S. Averichev, X. Bai, V. Bairathi, A. Behera, R. Bellwied, A. Bhasin, A. K. Bhati, P. Bhattarai, J. Bielcik, J. Bielcikova, L. C. Bland, I. G. Bordyuzhin, J. Bouchet, J. D. Brandenburg, A. V. Brandin, D. Brown, Renee H. Fatemi, Suvarna Ramachandran

Physics and Astronomy Faculty Publications

We present measurements of elliptic flow (ν₂) of electrons from the decays of heavy-flavor hadrons (e_HF) by the STAR experiment. For Au+Au collisions at √s_NN = 200 GeV we report v₂, for transverse momentum (p_T) between 0.2 and 7 GeV/c, using three methods: the event plane method (v₂{EP}), two-particle correlations (v₂{2}), and four-particle correlations (v₂{4}). For Au+Au collisions at √s_NN = 62.4 and 39 GeV we report v₂{2} for p_T < 2 GeV/c …