Dielectron Azimuthal Anisotrophy At Mid-Rapidity In Au+Au Collisions At √ˢᶰᶰ = 200 Gev,
2014
Old Dominion University
Dielectron Azimuthal Anisotrophy At Mid-Rapidity In Au+Au Collisions At √ˢᶰᶰ = 200 Gev, L. Adamczyk, J. K. Adkins, G. Agakishiev, S. Bültmann, I Koralt, Star Collaboration
Physics Faculty Publications
We report on the first measurement of the azimuthal anisotropy v2 of dielectrons (e+e- pairs) at mid-rapidity from √ˢᶰᶰ = 200 GeV Au + Au collisions with the STAR detector at the Relativistic Heavy Ion Collider (RHIC), presented as a function of transverse momentum pT for different invariant-mass regions. In the mass region Mee < 1.1 GeV/c2 the dielectron v2measurements are found to be consistent with expectations from π0, η, ω, and Φ decay contributions. In the mass region 1.1 < Mee < 2.9 GeV/c2, the measured dielectron v2is consistent, within experimental …
Data Analysis Techniques, Differential Cross Sections, And Spin Density Matrix Elements For The Reaction ᵞp → Φp,
2014
Old Dominion University
Data Analysis Techniques, Differential Cross Sections, And Spin Density Matrix Elements For The Reaction ᵞp → Φp, K.P. Adhikari, D. Adikaram, M.J. Amaryan, A. Klein, S. Koirala, Clas Collaboration
Physics Faculty Publications
High-statistics measurements of differential cross sections and spin density matrix elements for the reaction ᵞp → ϕp have been made using the CLAS detector at Jefferson Lab. We cover center-of-mass energies (√s) from 1.97 to 2.84 GeV, with an extensive coverage in the ϕ production angle. The high statistics of the data sample made it necessary to carefully account for the interplay between the ϕ natural lineshape and effects of the detector resolution, that are found to be comparable in magnitude. We study both the charged-(ϕ → K+ K-) and neutral( ϕ → (KOSK …
Exclusive Πᵒ Electroproduction At W > 2 Gev With Clas,
2014
Old Dominion University
Exclusive Πᵒ Electroproduction At W > 2 Gev With Clas, I. Bedlinskiy, K. P. Adhikari, L. El Fassi, A. Klein, S. E. Kuhn, Clas Collaboration
Physics Faculty Publications
Exclusive neutral-pion electroproduction (ep → e'p'π0 was measured at Jefferson Lab with a 5.75-GeV electron beam and the CLAS detector. Differential cross sections d4σ/dtdQ2dxBdΦπ and structure functions σT+ ϵσL, σTT, and σLT as functions of t were obtained over a wide range of Q2 and xB. The data are compared with Regge and handbag theoretical calculations. Analyses in both frameworks find that a large dominance of transverse processes is necessary to explain the experimental results. For the Regge analysis it is found …
Event Plane Dependent Dihadron Correlations With Harmonic Vⁿ Subtraction In Au + Au Collisions At √ˢᴺᴺ = 200 Gev,
2014
Old Dominion University
Event Plane Dependent Dihadron Correlations With Harmonic Vⁿ Subtraction In Au + Au Collisions At √ˢᴺᴺ = 200 Gev, H. Agakishiev, M. M. Aggarwal, Z. Ahammed, S. Bueltmann, D. Plyku, Star Collaboration
Physics Faculty Publications
STAR measurements of dihadron azimuthal correlations (ΔΦ) are reported in midcentral (20-60%) Au + Au collisions at √ˢᴺᴺ = 200 GeV as a function of the trigger particle's azimuthal angle relative to the event plane, Φs = | Φt- ΨEP|. The elliptic (v2), triangular (v3), and quadratic (v4) flow harmonic backgrounds are subtracted using the zero yield at minimum (ZYAM) method. It is found that a finite near-side (|ΔΦ| < π/2) long-range pseudorapidity correlation (ridge) is present in the in-plane direction (Φs ~ 0). The away-side (|ΔΦ| > π/2) correlation shows a modification from d+ Au data, varying with Φs. …
Measurement Of "Pretzelosity" Asymmetry Of Charged Pion Production In Semi-Inclusive Deep Inelastic Scattering On A Polarized ³He Target,
2014
Old Dominion University
Measurement Of "Pretzelosity" Asymmetry Of Charged Pion Production In Semi-Inclusive Deep Inelastic Scattering On A Polarized ³He Target, Y. Zhang, X. Qian, K. Allada, C. Dutta, M. Canan, Jefferson Lab Hall A Collaboration
Physics Faculty Publications
An experiment to measure single-spin asymmetries of semi-inclusive production of charged pions in deep-inelastic scattering on a transversely polarized 3He target was performed at Jefferson Laboratory in the kinematic region of 0.16 < x < 0.35 and 1.4 < Q2 < 2.7 GeV2. Pretzelosity asymmetries on 3He, which are expressed as the convolution of the h┴1T transverse-momentum-dependent distribution functions and the Collins fragmentation functions in the leading order, were measured for the first time. Under the effective polarization approximation, we extracted the corresponding neutron asymmetries from the measured 3He asymmetries and cross-section ratios between the proton and 3He. Our results show that …
J/Ψ Production At Low Pᵀ In Au + Au And Cu + Cu Collisions At √ˢᴺᴺ = 200 Gev With The Star Detector,
2014
Old Dominion University
J/Ψ Production At Low Pᵀ In Au + Au And Cu + Cu Collisions At √ˢᴺᴺ = 200 Gev With The Star Detector, L. Adamczyk, J. K. Adkins, G. Agakishiev, S. Bültmann, I. Koralt, Star Collaboration
Physics Faculty Publications
The J/ψ pT spectrum and nuclear modification factor (RAA) are reported for pT < 5 GeV/c and |y| < 1 from 0% to 60% central Au + Au and Cu + Cu collisions at √ˢᴺᴺ = 200 GeV at STAR. A significant suppression of pT - integrated J/ψ production is observed in central Au + Au events. The Cu + Cu data are consistent with no suppression, although the precision is limited by the available statistics. RAA in Au + Au collisions exhibits a strong suppression at low transverse momentum and gradually increases with pT. The data are compared to high-pT STAR results and previously published BNL Relativistic Heavy Ion Collider results. Comparing with model calculations, it is found that the invariant yields …
Single Spin Asymmetries In Charged Kaon Production From Semi-Inclusive Deep Inelastic Scattering On A Transversely Polarized He-3 Target,
2014
Old Dominion University
Single Spin Asymmetries In Charged Kaon Production From Semi-Inclusive Deep Inelastic Scattering On A Transversely Polarized He-3 Target, Y. X. Zhao, Y. Wang, K. Allada, K. Aniol, J. R. M. Annand, T. Averett, F. Benmokhtar, W. Bertozzi, P. C. Bradshaw, M. Canan
Physics Faculty Publications
We report the first measurement of target single spin asymmetries of charged kaons produced in semi-inclusive deep inelastic scattering of electrons off a transversely polarized 3He target. Both the Collins and Sivers moments, which are related to the nucleon transversity and Sivers distributions, respectively, are extracted over the kinematic range of0.1 < xbj < 0.4for K+ and K− production. While the Collins and Sivers moments for K+ are consistent with zero within the experimental uncertainties, both moments for K− favor negative values. The Sivers moments are compared to the theoretical prediction from a phenomenological fit to the world data. While …
Precision Measurement Of The Neutron Twist-3 Matrix Element D(2)(N): Probing Color Forces,
2014
Old Dominion University
Precision Measurement Of The Neutron Twist-3 Matrix Element D(2)(N): Probing Color Forces, M. Posik, D. Flay, D. S. Parrno, K. Allada, W. Armstrong, F. Benmokhtar, M. Canan, L. El Fassi, S. Golge, C. Hyde
Physics Faculty Publications
Double-spin asymmetries and absolute cross sections were measured at large Bjorken x (0.25 ≤ x ≤ 0.90), in both the deep-inelastic and resonance regions, by scattering longitudinally polarized electrons at beam energies of 4.7 and 5.9 GeV from a transversely and longitudinally polarized 3He target. In this dedicated experiment, the spin structure function g(2)(3He) was determined with precision at large x, and the neutron twist-3 matrix element d(2)(n) was measured at < Q2> of 3.21 and 4.32 GeV2/c2, with an absolute precision of about 10-5. Our results are found to be in agreement …
Probing The Repulsive Core Of The Nucleon-Nucleon Interaction Via The 4he( E, E′ Pn) Triple-Coincidence Reaction,
2014
Old Dominion University
Probing The Repulsive Core Of The Nucleon-Nucleon Interaction Via The 4he( E, E′ Pn) Triple-Coincidence Reaction, I. Korover, N. Muangma, O. Hen, R. Shneor, V. Sulkosky, A. Kelleher, S. Gilad, D. W. Higinbotham, H. Albataineh, L. B. Weinstein
Physics Faculty Publications
We studied simultaneously the 4He(e,e′p), 4He (e,e′pp), and 4He( e,e′pn) reactions at Q2 = 2(GeV/c)2 and xB > 1,for an (e,e′p) missing-momentum range of 400 to 830 MeV/c. The knocked-out proton was detected in coincidence with a proton or neutron recoiling almost back to back to the missing momentum, leaving the residual A = 2 system at low excitation energy. These data were used to identify two-nucleon short-range correlated pairs and to deduce their isospin structure as a function of missing momentum, in a region where the nucleon-nucleon (NN) …
Separated Response Function Ratios In Exclusive, Forward Π± Electroproduction,
2014
Old Dominion University
Separated Response Function Ratios In Exclusive, Forward Π± Electroproduction, G. M. Huber, H. P. Blok, C. Butuceanu, D. Gaskell, T. Horn, D. J. Mack, D. Abbott, A. Klein, L. M. Qin, K. Vansyoc
Physics Faculty Publications
The study of exclusive π± electroproduction on the nucleon, including separation of the various structure functions, is of interest for a number of reasons. The ratio R-L=sigma(pi-)(L) / sigma(pi+)(L) is sensitive to isoscalar contamination to the dominant isovector pion exchange amplitude, which is the basis for the determination of the charged pion form factor from electroproduction data. A change in the value of R-T=sigma(pi-)(L) / sigma(pi+)(L) from unity at small -t, to 1/4 at large -t, would suggest a transition from coupling to a (virtual) pion to coupling to individual quarks. Furthermore, the mentioned ratios may show an earlier …
Induced Polarization Of Λ1116 In Kaon Electroproduction,
2014
Old Dominion University
Induced Polarization Of Λ1116 In Kaon Electroproduction, Clas Collaboration, D. Adikaram, M. J. Amaryan, L. El Fassi, S. Koirala, S. E. Kuhn, M. Mayer
Physics Faculty Publications
We have measured. the induced polarization of the Λ (1116) in the reaction ep →e′K+Λ , detecting the scattered e′ and K+ in the final state along with the proton from the decay Λ → pπ− . The present study used the CEBAF Large Acceptance Spectrometer (CLAS), which allowed for a large kinematic acceptance in invariant energy W (1.6≤ W ≤ 2.7 GeV) and covered the full range of the kaon production angle at an average momentum transfer Q2 = 1.90GeV2 . In this experiment a 5.50-GeV electron beam was incident upon …
Beam-Spin Asymmetries From Semi-Inclusive Pion Electroproduction,
2014
Old Dominion University
Beam-Spin Asymmetries From Semi-Inclusive Pion Electroproduction, K. P. Adhikari, M. J. Amaryan, C. Hyde, S. Koirala, S. E. Kuhn, L. B. Weinstein, Et Al., The Clas Collaboration
Physics Faculty Publications
We have measured the moment Asin ɸLU corresponding to the polarized electron beam-spin asymmetry in semi-inclusive deep inelastic scattering. Asin ɸLU is a twist-3 quantity providing information about quark-gluon correlations. Data were taken with the CLAS Spectrometer at Jefferson Lab using a 5.498 GeV longitudinally polarized electron beam and an unpolarized liquid hydrogen target. All three pion channels (π+,π0 and π-) were measured simultaneously over a large range of kinematics within the virtuality range Q2 ≈ 1.0- 4.5 GeV2. The observable was measured with better than 1% statistical …
The Emc Effect In Spin Structure Functions,
2014
Universidad Téchnica Federico Santa María
The Emc Effect In Spin Structure Functions, W. K. Brooks, H. Hakobyan, B. Kopeliovich, S. Kuleshov, S. Mancilla, R. Mendez, K. Adhikari, G. Dodge, L. El Fassi, S. Kuhn, L. Weinstein, H. Avakian, A. Deur, D. Higinbotham, C. Keith, W. Melnitchouk, J. Pierce, D. Crabb, D. Keller, S. Tkachenko, J. Zhang, P. E. Bosted, K. Griffioen, K. Hicks, R. Dupré, T. Badman, S. Li, E. Long, K. Slifer, P. Solvignon, R. Zielinski, N. Kalantarians, F. J. Klein, A. W. Thomas, W. Bentz, I. Cloet, R. B. Wiringa, C. Ciofi Degli Atti, H. Fanchiotti, C. A. Garcia Canal, T. Tarutina, V. Vento
Physics Faculty Publications
We propose to perform the first measurements of the spin-dependent EMC effect utilizing CLAS12 in Hall B with 11 GeV polarized electrons and polarized nuclear targets. Our target of choice is ⁷Li (in the form of dynamically polarized ⁷LiD) in which a highly polarized proton is embedded in the nuclear medium. Simultaneously, we will also measure the double spin asymmetry on the proton with a ⁶LiH target, to minimize systematic uncertainties. The experiment will obtain the double spin asymmetry A ⁷IILi ≈ g⁷₁Li from the measurement on ⁷LiD, after correcting for the small contribution from other polarized …
Measurement Of Charge Multiplicity Asymmetry Correlations In High-Energy Nucleus-Nucleus Collisions At √ˢᶰᶰ = 200 Gev,
2014
Old Dominion University
Measurement Of Charge Multiplicity Asymmetry Correlations In High-Energy Nucleus-Nucleus Collisions At √ˢᶰᶰ = 200 Gev, L. Adamczyk, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, S. Bültmann, Star Collaboration
Physics Faculty Publications
A study is reported of the same-and opposite-sign charge-dependent azimuthal correlations with respect to the event plane in Au+ Au collisions at √ˢᶰᶰ = 200 GeV. The charge multiplicity asymmetries between the up/down and left/right hemispheres relative to the event plane are utilized. The contributions from statistical fluctuations and detector effects were subtracted from the (co-) variance of the observed charge multiplicity asymmetries. In the mid-to most-central collisions, the same- (opposite-) sign pairs are preferentially emitted in back-to-back (aligned on the same-side) directions. The charge separation across the event plane, measured by the difference, Δ, between the like-and unlike-sign up/down-left/right …
Virtuality Distributions In Application To Ɣɣ* → Π0 Transition Form Factor At Handbag Level,
2014
Old Dominion University
Virtuality Distributions In Application To Ɣɣ* → Π0 Transition Form Factor At Handbag Level, Anatoly V. Radyushkin
Physics Faculty Publications
We outline basics of a new approach to transverse momentum dependence in hard processes. As an illustration, we consider hard exclusive transition process ɣ*ɣ -> π0 at the handbag level. Our starting point is coordinate representation for matrix elements of operators (in the simplest case, bilocal O(0, z)) describing a hadron with momentum p. Treated as functions of (pz) and z2, they are parametrized through virtuality distribution amplitudes (VDA) Φ(x, σ), with x being Fourier-conjugate to (pz) and σ Laplace-conjugate to z2. For intervals with z+ = 0, we introduce the transverse momentum distribution …
The Dijet Cross Section Measurement In Proton-Proton Collisions At A Center Of Mass Energy Of 500 Gev At Star,
2014
University of Kentucky
The Dijet Cross Section Measurement In Proton-Proton Collisions At A Center Of Mass Energy Of 500 Gev At Star, Grant D. Webb
Theses and Dissertations--Physics and Astronomy
Polarized deep inelastic scattering experiments play a vital role in the exploration of the spin structure of the proton. The polarized proton-proton collider at RHIC provides direct access to the gluon spin distribution through longitudinal double spin asymmetry measurements of inclusive jets, pions, and dijets. This thesis presents the measurement of the dijet double differential cross-section in proton-proton collisions at center of mass energies of √s = 500 GeV. The data represent an integrated luminosity of 8.7 pb-1 recorded by the STAR detector during the 2009 RHIC run. A comprehensive jet analysis was performed to determine the ideal …
Nuclear Structure Relevant To Double-Beta Decay: Studies Of ⁷⁶Ge And ⁷⁶Se Using Inelastic Neutron Scattering,
2014
University of Kentucky
Nuclear Structure Relevant To Double-Beta Decay: Studies Of ⁷⁶Ge And ⁷⁶Se Using Inelastic Neutron Scattering, Benjamin P. Crider
Theses and Dissertations--Physics and Astronomy
While neutrino oscillations indicate that neutrino flavors mix and that neutrinos have mass, they do not supply information on the absolute mass scale of the three flavors of neutrinos. Currently, the only viable way to determine this mass scale is through the observation of the theoretically predicted process of neutrinoless double-beta decay (0νββ). This yet-to-be-observed decay process is speculated to occur in a handful of nuclei and has predicted half-lives greater than 10²⁵ years. Observation of 0νββ is the goal of several large-scale, multinational efforts and consists of detecting a sharp peak in the summed β energies at the Q-value …
Photoproduction Of Π0 On Hydrogen With Clas From 1.1 Gev - 5.45 Gev Using E+E –Γ Decay,
2014
Old Dominion University
Photoproduction Of Π0 On Hydrogen With Clas From 1.1 Gev - 5.45 Gev Using E+E –Γ Decay, Michael C. Kunkel
Physics Theses & Dissertations
Photoproduction of the π0 meson was studied using the CLAS detector at the Thomas Jefferson National Accelerator Facility using tagged incident photon energies spanning the range Eγ = 1.1 GeV - 5.45 GeV. The measurement is performed on a liquid hydrogen target in the reaction γp → pe +e–(γ). The final state of the reaction is the sum of two subprocesses for π0 decay, the Dalitz decay mode of π0 → e +e–γ and conversion mode where one photon from π0 → γγ decay is converted into a …
Radiogenic Second Cancer Risk Differences In Female Hodgkin Lymphoma Patients Treated With Proton Versus Photon Radiotherapies,
2013
The University of Texas Graduate School of Biomedical Sciences at Houston
Radiogenic Second Cancer Risk Differences In Female Hodgkin Lymphoma Patients Treated With Proton Versus Photon Radiotherapies, Kenneth L. Homann
Dissertations and Theses (Open Access)
Hodgkin Lymphoma (HL) is the most common cancer diagnosis of young adults in the United States. Advances in curative treatments for HL, including the use of photon radiation therapy (RT) techniques, have increased 10 year survival rates to approximately 90% among young patients. These RT treatments, however, contribute to an increased incidence of radiogenic second cancer (RSC) formation to the healthy tissue surrounding the tumor volume relative to the general population. These RSCs are the leading cause of death among long-term HL survivors. Proton therapy has been shown to reduce the therapeutic dose, and therefore, the risk of developing a …
Criticality And Characteristic Neutronic Analysis Of A Transient-State Shockwave In A Pulsed Spherical Gaseous Uranium-Hexafluoride Reactor,
2013
University of Nevada, Las Vegas
Criticality And Characteristic Neutronic Analysis Of A Transient-State Shockwave In A Pulsed Spherical Gaseous Uranium-Hexafluoride Reactor, Jeremiah Boles
UNLV Theses, Dissertations, Professional Papers, and Capstones
The purpose of this study is to analyze the theoretical criticality of a spherical uranium-hexafluoride reactor with a transient, pulsed shockwave emanating from the center of the sphere in an outward-radial direction. This novel nuclear reactor design, based upon pulsed fission in a spherical enclosure is proposed for possible use in direct energy conversion, where the energy from fission products is captured through the use of electrostatic fields or through induction. An analysis of the dynamic behavior of the shockwave in this reactor is the subject of this thesis. As a shockwave travels through a fluid medium, the characteristics of …
