Physics Commons^™

Momentum Distributions For 2H (E, E' P), William P. Ford, Sabine Jeschonnek, J. W. Van Orden

Faculty Publications

Background: A primary goal of deuteron electrodisintegration is the possibility of extracting the deuteron momentum distribution. This extraction is inherently fraught with difficulty, as the momentum distribution is not an observable and the extraction relies on theoretical models dependent on other models as input.

Purpose: We present a new method for extracting the momentum distribution which takes into account a wide variety of model inputs thus providing a theoretical uncertainty due to the various model constituents. To test the extraction, pseudodata were generated, and the extracted “experimental” distribution, which has theoretical uncertainty accounted by this extraction method, can be compared …

Nuclear Structure Aspects Of Neutrinoless Double Beta Decay, B. Alex Brown, Mihai Horoi, Roman A. Sen′Kov

Publications and Research

We decompose the neutrinoless double-beta decay matrix elements into sums of products over the intermediate nucleus with two less nucleons. We find that the sum is dominated by the J^pi=0^+ ground state of this intermediate nucleus for both the light and heavy neutrino decay processes. This provides a new theoretical tool for comparing and improving nuclear structure models. It also provides the connection to two-nucleon transfer experiments.

Iranian Nuclear Proliferation And Sanctions, Bailey Nicole Burlingame

Student Scholar Symposium Abstracts and Posters

This project will involve the current problem of nuclear development in the nation of Iran. The question involved in the election studies was, “Should we try to stop Iranian Nuclear Development by increasing sanctions, yes or no?” According to the US Department of State website, they are attempting to increase these sanctions against individuals or cooperations who can be proven to have provided aid, information, or mechanical aspects to assist the goal of Iranian nuclear proliferation. The website provides identifying information for the individuals involved. The answer to this question I believe will be determined the amount of news information …

Elastic Differential Cross Sections For Space Radiation Applications, Charles M. Werneth, Khin M. Maung, William P. Ford, John W. Norbury, Michael D. Vera

Faculty Publications

The eikonal, partial wave (PW) Lippmann-Schwinger, and three-dimensional Lippmann-Schwinger (LS3D) methods are compared for nuclear reactions that are relevant for space radiation applications. Numerical convergence of the eikonal method is readily achieved when exact formulas of the optical potential are used for light nuclei (>A≤>16), and the momentum-space representation of the optical potential is used for heavier nuclei. The PW solution method is known to be numerically unstable for systems that require a large number of partial waves, and, as a result, the LS3D method is employed. The effect of relativistic kinematics is studied with the PW and …

Epa's Proposed Greenhouse Gas Regulation For Power Plants: How Does It Work And What Will It Mean For Nevada?, Adele C. Morris

Brookings Scholar Lecture Series

In June, the Environmental Protection Agency proposed important new limits on carbon dioxide emissions from existing U.S. power plants. The new regulation is the centerpiece of the Obama Administration’s climate policy. If the controversial rule is finalized as planned next year, it will cover about a third of U.S. greenhouse gas emissions. This lecture will explain the legal, environmental, and economic issues posed by the rule and highlight the important role for states in implementing it. The lecture will also review the implications and options for achieving the emissions target the EPA set for Nevada.

Mcdaniel, Paul William, 1916-2004 (Mss 515), Manuscripts & Folklife Archives

MSS Finding Aids

Finding aid only for Manuscripts Collection 515. Writings and awards of Paul William McDaniel, nuclear physicist and graduate of Western Kentucky University. Includes typescripts of lectures delivered at Queensland University, a journal he kept while serving in World War II, and a copy of his Arthur F. Fleming Award. Also includes many letters of congratulations to him and a copy of the Atomic Energy Act of 1946.

Proton Form Factor Puzzle And The Cebaf Large Acceptance Spectrometer(Clas) Two-Photon Exchange Experiment, Dipak Rimal

FIU Electronic Theses and Dissertations

The electromagnetic form factors are the most fundamental observables that encode information about the internal structure of the nucleon. The electric ($G_{E}$) and the magnetic ($G_{M}$) form factors contain information about the spatial distribution of the charge and magnetization inside the nucleon. A significant discrepancy exists between the Rosenbluth and the polarization transfer measurements of the electromagnetic form factors of the proton. One possible explanation for the discrepancy is the contributions of two-photon exchange (TPE) effects. Theoretical calculations estimating the magnitude of the TPE effect are highly model dependent, and limited experimental evidence for such effects exists. Experimentally, the TPE …

Understanding Thermometry At Low Temperature, Zain Abbas

Student Research Projects

Cryogenics play a vital role in building a Dynamic Nuclear Polarization (DNP) target for electron scattering experiments. The target material temperature was monitored using thermometry in order to evaluate their stability for use in the low temperature cryogenic bath of a DNP target. In this project, I investigated there solutions and accuracies of carbon ceramic, Cernox, Allen-Bradley, and thermocouple sensors at five known temperatures.

Analyzing Heavy Photon Search Simulations To Determine The Potential For True Muonium Discovery, Chad N. Civello

Student Research Projects

The Heavy Photon Search (HPS) is a new experiment at Jefferson Laboratory to search for heavy photons, a particle predicted by dark matter and dark energy extensions to the Standard Model of particle physics, in the mass range of 20 MeV/c² to 1000 MeV/c² . The experiment also has the potential to discover true muonium, a bound state of a muon and an antimuon that is predicted to exist, but has never been observed. The true muonium atom should be produced by an electron beam incident on a target, such as the tungsten target used in the HPS …

Boosted Top Production: Factorization And Resummation For Single-Particle Inclusive Distributions, Andrea Ferroglia, Simone Marzani, Ben D. Pecjak, Li Lin Yang

Publications and Research

We study single-particle inclusive (1PI) distributions in top-quark pair production at hadron colliders, working in the highly boosted regime where the top-quarkpTis much larger than its mass. In particular, we derive a novel factorization formula validin the small-mass and soft limits of the differential partonic cross section. This providesa framework for the simultaneous resummation of soft gluon corrections and small-mass logarithms, and also an efficient means of obtaining higher-order corrections to the differential cross section in this limit. The result involves five distinct one-scale functions, three of which arise through the subfactorization of soft real radiation in the small-mass limit. …

A Numerical Assessment Of Cosmic-Ray Energy Diffusion Through Turbulent Media, M. Fatuzzo, F. Melia

Faculty Scholarship

No abstract provided.

Effects Of Turbulence On Cosmic Ray Propagation In Protostars And Young Stars, M. Fatuzzo, F. C. Adams

Faculty Scholarship

No abstract provided.

Narrow-Band Emission In Thomson Sources Operating In The High-Field Regime, Balša Terzić, Kirsten Deitrick, Alicia S. Hofler, Geoffrey A. Krafft

Physics Faculty Publications

We present a novel and quite general analysis of the interaction of a high-field chirped laser pulse and a relativistic electron, in which exquisite control of the spectral brilliance of the up-shifted Thomson-scattered photon is shown to be possible. Normally, when Thomson scattering occurs at high field strengths, there is ponderomotive line broadening in the scattered radiation. This effect makes the bandwidth too large for some applications and reduces the spectral brilliance. We show that such broadening can be corrected and eliminated by suitable frequency modulation of the incident laser pulse. Furthermore, we suggest a practical realization of this compensation …

Beam-Energy Dependence Of Charge Separation Along The Magnetic Field In Au + Au Collisions At Rhic, L. Adamczyk, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, C. D. Anson, A. Aparin, D. Arkhipkin, E. C. Aschenauer, G. S. Averichev, A. Banerjee, D. R. Beavis, R. Bellwied, A. Bhasin, A. K. Bhati, P. Bhattarai, H. Bichsel, M. Zyzak, Et Al., Star Collaboration

Physics Faculty Publications

Local parity-odd domains are theorized to form inside a quark-gluon plasma which has been produced in high-energy heavy-ion collisions. The local parity-odd domains manifest themselves as charge separation along the magnetic field axis via the chiral magnetic effect. The experimental observation of charge separation has previously been reported for heavy-ion collisions at the top RHIC energies. In this Letter, we present the results of the beam-energy dependence of the charge correlations in Au+Au collisions at midrapidity for center-of-mass energies of 7.7, 11.5, 19.6, 27, 39, and 62.4 GeV from the STAR experiment. After background subtraction, the signal gradually reduces with …

Virtuality Distributions In Application To Ɣɣ* → Π​0 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 …

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 → (K^O_SK …

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 p_T for different invariant-mass regions. In the mass region M_ee < 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 < M_ee < 2.9 GeV/c², the measured dielectron v₂is consistent, within experimental …

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/dtdQ²dx_BdΦ_π and structure functions σ_T+ ϵσ_L, σ_TT, and σ_LT as functions of t were obtained over a wide range of Q² and x_B. 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 …

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, L. Adamczyk, J. K. Adkins, G. Agakishiev, S. Bültmann, I. Koralt, Star Collaboration

Physics Faculty Publications

The J/ψ p_T spectrum and nuclear modification factor (R_AA) are reported for p_T < 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 p_T - 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. R_AA in Au + Au collisions exhibits a strong suppression at low transverse momentum and gradually increases with p_T. The data are compared to high-p_T STAR results and previously published BNL Relativistic Heavy Ion Collider results. Comparing with model calculations, it is found that the invariant yields …

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 …

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, 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, 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, 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, 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 A^{sin ɸ}_LU corresponding to the polarized electron beam-spin asymmetry in semi-inclusive deep inelastic scattering. A^{sin ɸ}_LU 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 …

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 < x_bj < 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 …

J/Ѱ Polarization In P+P Collisions At √S = 200 Gev In Star, L. Adamczyk, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, C. D. Anson, A. Aparin, D. Arkhipkin, S. Bültmann

Physics Faculty Publications

We report on a polarization measurement of inclusive J/Ѱ mesons in the di-electron decay channel at mid-rapidity at 2 < p_T < 6 GeV/c in p + p collisions at √s = 200 GeV. Data were taken with the STAR detector at RHIC. The J/Ѱ polarization measurement should help to distinguish between different models of the J/Ѱ production mechanism since they predict different p_T dependences of the J/Ѱ polarization. In this analysis, J/Ѱ is studied in the helicity frame. The polarization parameter λ_θ measured at RHIC becomes smaller towards high p_T, indicating more longitudinal J/Ѱ polarization as p_T increases. The result is compared with predictions of presently available models.

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, Φ_s = | Φ_t- Ψ_EP|. 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 (Φ_s ~ 0). The away-side (|ΔΦ| > π/2) correlation shows a modification from d+ Au data, varying with Φ_s. …