Nuclear Commons^™

Single-Neutron States In Titanium Isotopes, Jessica Nebel-Crosson

Physics and Astronomy Summer Fellows

Current theory regarding the collective behavior of exotic nuclei systematically over-predicts the probabilities of exciting those collective states. The theory lacks any adjustable parameters, however, the model inputs are characteristics of single particle states which we are attempting to verify through neutron transfer into a ⁵⁰Ti target.

Measurement Of Two-Particle Correlations With Respect To Second- And Third-Order Event Planes In Au + Au Collisions At √Snn=200 Gev, A. Adare, John C. Hill, Nels J. Hotvedt, Todd Kempel, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, H. Pei, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Alexey Yu. Semenov, M. Shimomura, Carla Vale, Feng Wei, Et Al.

Craig Ogilvie

We present measurements of azimuthal correlations of charged hadron pairs in root s(NN) = 200 GeV Au + Au collisions for the trigger and associated particle transverse-momentum ranges of 1 < p(T)(t) < 10 GeV/c and 0.5 < p(T)(a) < 10 GeV/c. After subtraction of an underlying event using a model that includes higher-order azimuthal anisotropy v(2), v(3,) and v(4), the away-side yield of the highest trigger-p(T)(p(T)(t) > 4 GeV/c) correlations is suppressed compared with that of correlations measured in p + p collisions. At the lowest associated particle p(T)(0.5 < p(T)(a) < 1 GeV/c), the away-side shape and yield are modified relative to those in p + p collisions. These observations are consistent with the scenario of radiative-jet energy loss. For the low-p(T) trigger correlations (2 < p(T)(t) < 4 GeV/c), a finite away-side yield exists and we explore the dependence of the shape of the away-side within the context of an underlying-event model. Correlations are also studied differentially versus event-plane angle Psi(2) and Psi(3). The angular correlations show an asymmetry when selecting the sign of the difference between the trigger-particle azimuthal angle and the Psi(2) event plane. This asymmetry and the measured suppression of the pair yield out-of-plane is consistent with a path-length-dependent energy loss. No Psi(3) dependence can be resolved within experimental uncertainties.

Nonperturbative-Transverse-Momentum Broadening In Dihadron Angular Correlations In √Snn = 200 Gev Proton-Nucleus Collisions, C. Aidala, Nicole J. Apadula, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Et Al.

Craig Ogilvie

The PHENIX collaboration has measured high-pT dihadron correlations in p+p, p+Al, and p+Au collisions at √sNN=200 GeV. The correlations arise from inter- and intrajet correlations and thus have sensitivity to nonperturbative effects in both the initial and final states. The distributions of pout, the transverse-momentum component of the associated hadron perpendicular to the trigger hadron, are sensitive to initial- and final-state transverse momenta. These distributions are measured multidifferentially as a function of xE, the longitudinal momentum fraction of the associated hadron with respect to the trigger hadron. The near-side pout widths, sensitive to fragmentation transverse momentum ...

Production Of Π0 And Η Mesons In Cu + Au Collisions At √Snn = 200 Gev, C. Aidala, Nicole J. Apadula, Sarah C. Campbell, Lei Ding, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, Alex Shaver, M. Shimomura, Arbin Timilsina, Shawn Whitaker, Et Al.

Craig Ogilvie

Production of π0 and η mesons has been measured at midrapidity in Cu+Au collisions at √sNN=200 GeV. Measurements were performed in π0(η)→γγ decay channel in the 1(2)−20 GeV/c transverse momentum range. A strong suppression is observed for π0 and η meson production at high transverse momentum in central Cu+Au collisions relative to the p+p results scaled by the number of nucleon-nucleon collisions. In central collisions the suppression is similar to Au+Au with comparable nuclear overlap. The η/π0 ratio measured as a function of transverse momentum is consistent with mT-scaling ...

Measurements Of Multiparticle Correlations In D + Au Collisions At 200, 62.4, 39, And 19.6 Gev And P + Au Collisions At 200 Gev And Implications For Collective Behavior, C. Aidala, Nicole J. Apadula, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Et Al.

Craig Ogilvie

Recently, multiparticle-correlation measurements of relativistic p/d(3)He + Au, p + Pb, and even p + p collisions show surprising collective signatures. Here, we present beam-energy-scan measurements of two, four-, and six-particle angular correlations in d + Au collisions at root s(NN) = 200, 62.4, 39, and 19.6 GeV. We also present measurements of two-and four-particle angular correlations in p + Au collisions at root s(NN) = 200 GeV. We find the four-particle cumulant to be real valued for d + Au collisions at all four energies. We also find that the four-particle cumulant in p + Au has the opposite sign as ...

Measurements Of Mass-Dependent Azimuthal Anisotropy In Central P + Au, D + Au, And 3he + Au Collisions At √Snn = 200 Gev, A. Adare, Nicole J. Apadula, Sarah C. Campbell, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Et Al.

Craig Ogilvie

We present measurements of the transverse-momentum dependence of elliptic flow upsilon(2) for identified pions and (anti)protons at midrapidity (vertical bar eta vertical bar < 0.35), in 0%-5% central p + Au and He-3 + Au collisions at ,root s(NN) = 200 GeV. When taken together with previously published measurements in d + Au collisions at root s(NN) = 200 GeV, the results cover a broad range of small-collision-system multiplicities and intrinsic initial geometries. We observe a clear mass-dependent splitting of upsilon(2) (p(T)) in d + Au and He-3 + Au collisions, just as in large nucleus-nucleus (A + A) collisions, and a smaller splitting in p + Au collisions. Both hydrodynamic and transport model calculations successfully describe the data at low p(T) (<1.5 GeV/c), but fail to describe various features at higher p(T). In all systems, the upsilon(2) values follow an approximate quark-number scaling as a function of the hadron transverse kinetic energy per constituent quark (KET/n(q)), which was also seen previously in A + A collisions.

Measurements Of E+E− Pairs From Open Heavy Flavor In P + P And D + A Collisions At √ Snn = 200 Gev, A. Adare, Nicole Apadula, John C. Hill, Nels J. Hotvedt, Todd Kempel, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, Milap R. Patel, H. Pei, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Alexey Yu. Semenov, Abhisek Sen, M. Shimomura, Arbin Timilsina, Carla Vale, Feng Wei, Et. Al

Craig Ogilvie

We report a measurement of e+e− pairs from semileptonic heavy-flavor decays in p+p collisions at √sNN=200 GeV. The e+e− pair yield from b¯b and c¯c is separated by exploiting a double differential fit done simultaneously in dielectron invariant mass and pT. We used three different event generators, pythia, mc@nlo, and powheg, to simulate the e+e− spectra from c¯c and b¯b production. The data can be well described by all three generators within the detector acceptance. However, when using the generators to extrapolate to 4π, significant differences are observed for the ...

Nuclear Dependence Of The Transverse-Single-Spin Asymmetry For Forward Neutron Production In Polarized P+A Collisions At √Snn=200 Gev, C. Aidala, Nicole J. Apadula, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Et Al.

Craig Ogilvie

During 2015, the Relativistic Heavy Ion Collider (RHIC) provided collisions of transversely polarized protons with Au and Al nuclei for the first time, enabling the exploration of transverse-single-spin asymmetries with heavy nuclei. Large single-spin asymmetries in very forward neutron production have been previously observed in transversely polarized p+p collisions at RHIC, and the existing theoretical framework that was successful in describing the single-spin asymmetry in p+p collisions predicts only a moderate atomic-mass-number (A) dependence. In contrast, the asymmetries observed at RHIC in p+A collisions showed a surprisingly strong A dependence in inclusive forward neutron production. The observed ...

Measurements Of Azimuthal Anisotropy And Charged-Particle Multiplicity In D + Au Collisions At √Snn = 200, 62.4, 39, And 19.6 Gev, C. Aidala, Nicole J. Apadula, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Et Al.

Craig Ogilvie

We present measurements of the elliptic flow (v(2)) as a function of transverse momentum (p(T)), pseudorapidity (eta), and centrality in d + Au collisions at root s(NN) = 200, 62.4, 39, and 19.6 GeV. The beam-energy scan of d + Au collisions provides a testing ground for the onset of flow signatures in small collision systems. We measure a nonzero v(2) signal at all four collision energies, which, at midrapidity and low p(T), is consistent with predictions from viscous hydrodynamic models. Comparisons with calculations from parton transport models (based on the AMPT Monte Carlo generator) show ...

Measurement Of Emission-Angle Anisotropy Via Long-Range Angular Correlations With High-Pt Hadrons In D + Au And P + P Collisions At √Snn = 200 Gev, A. Adare, Nicole J. Apadula, Alan Dion, John C. Hill, Nels J. Hotvedt, Todd Kempel, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, H. Pei, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, C. L. Silva, Arbin Timilsina, Feng Wei, Et Al.

Craig Ogilvie

We present measurements of two-particle angular correlations between high-transverse-momentum (2 < pT < 11 GeV/c) pi(0) observed at midrapidity (|eta| < 0.35) and particles produced either at forward (3.1 < eta < 3.9) or backward (-3.7 < eta < -3.1) rapidity in d + Au and p + p collisions at root s(NN) = 200 GeV. The azimuthal angle correlations for particle pairs with this large rapidity gap in the Au-going direction exhibit a characteristic structure that persists up to pT approximate to 6 GeV/c and which strongly depends on collision centrality, which is a similar characteristic to the hydrodynamical particle flow in A + A collisions. The structure is absent in the d-going direction as well as in p + p collisions, in the transverse-momentum range studied. The results indicate that the structure is shifted in the Au-going direction toward more central collisions, similar to the charged-particle pseudorapidity distributions.

B-Meson Production At Forward And Backward Rapidity In P+P And Cu+Au Collisions At √Snn=200 Gev, C. Aidala, Nicole J. Apadula, John C. Hill, Nels J. Hotvedt, Todd Kempel, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, Alex Shaver, M. Shimomura, Arbin Timilsina, Shawn Whitaker, Et Al.

Craig Ogilvie

The fraction of J/psi mesons which come from B-meson decay, F-B -> J/psi is measured for J/psi rapidity 1.2 < |y| < 2.2 and p(T) > 0 in p + p and Cu+Au collisions at root s(NN) = 200 GeV with the PHENIX detector. The extracted fraction is F-B -> J/psi = 0.025 +/- 0.006 (stat) +/- 0.010(syst) for p + p collisions. For Cu+Au collisions, F-B -> J/psi is 0.094 +/- 0.028(stat) +/- 0.037(syst) in the Au-going direction (-2.2 < y < -1.2) and 0.089 +/- 0.026(stat) +/- 0.040(syst) in the Cu-going direction (1.2 < y < 2.2). The nuclear modification factor, R-CuAu,of B mesons in Cu+Au collisions is consistent with binary scaling of measured yields in p + p at both forward and backward rapidity.

Creation Of Quark–Gluon Plasma Droplets With Three Distinct Geometries, C. Aidala, Nicole J. Apadula, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, Joshua Perry, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, Arbin Timilsina, Et Al.

Craig Ogilvie

Experimental studies of the collisions of heavy nuclei at relativistic energies have established the properties of the quark–gluon plasma (QGP), a state of hot, dense nuclear matter in which quarks and gluons are not bound into hadrons 1–4 . In this state, matter behaves as a nearly inviscid fluid 5 that efficiently translates initial spatial anisotropies into correlated momentum anisotropies among the particles produced, creating a common velocity field pattern known as collective flow. In recent years, comparable momentum anisotropies have been measured in small-system proton–proton (p+p) and proton–nucleus (p+A) collisions, despite expectations that the ...

Low-Momentum Direct-Photon Measurement In Cu + Cu Collisions At √Snn = 200 Gev, A. Adare, Nathan C. Grau, John C. Hill, Nels J. Hotvedt, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, H. Pei, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, M. Shimomura, S. Skutnik, Carla Vale, Feng Wei, Et Al.

Craig Ogilvie

We measured direct photons for pT<5GeV/c in minimum bias and 0%–40% most-central events at midrapidity for Cu+Cu collisions at √sNN=200 GeV. The e+e− contribution from quasireal direct virtual photons has been determined as an excess over the known hadronic contributions in the e+e−mass distribution. A clear enhancement of photons over the binary scaled p+p fit is observed for pT<4 GeV/c in Cu+Cu data. The pT spectra are consistent with the Au+Au data covering a similar number of participants. The inverse slopes of the exponential fits to the excess after subtraction of the p+p baseline are 285±53(stat)±57(syst)MeV/c and 333±72(stat)±45(syst)MeV/c for minimum bias and 0%–40% most-central events, respectively. The rapidity density, dN/dy, of photons demonstrates the same power law as a function of dNch/dη observed in Au+Au at the same collision energy.

Lévy-Stable Two-Pion Bose-Einstein Correlations In √Snn = 200 Gev Au + Au Collisions, A. Adare, Nicole J. Apadula, Lei Ding, Alan Dion, John C. Hill, Nels J. Hotvedt, Todd Kempel, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, H. Pei, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Abhisek Sen, M. Shimomura, C. L. Silva, Arbin Timilsina, Feng Wei, Et Al.

Craig Ogilvie

We present a detailed measurement of charged two-pion correlation functions in 0-30% centrality root= 200 GeV Au+Au collisions by the PHENIX experiment at the Relativistic Heavy Ion Collider. The data are well described by Bose-Einstein correlation functions stemming from Levy-stable source distributions. Using a fine transverse momentum binning, we extract the correlation strength parameter lambda, the Levy index of stability alpha, and the Levy length scale parameter R as a function of average transverse mass of the parr m(T). We find that the positively and the negatively charged pion pairs yield consistent results, and their correlation functions are ...

Electromagnetic Sum Rules And Response Functions From The Symmetry-Adapted No-Core Shell Model, Robert Byron Baker

LSU Doctoral Dissertations

Recent developments in ab initio nuclear structure have provided us with a variety of many-body methods capable of describing nuclei into the medium-mass region of the chart of nuclides. One of these, the symmetry-adapted no-core shell model (SA-NCSM), capitalizes on inherent symmetries of the nucleus and is uniquely suited to examine the underlying physics of dynamical quantities, such as the response function.

We examine the applicability of the SA-NCSM to calculations of these quantities and assess the quality of its inputs by calculating electromagnetic sum rules and response functions with the Lanczos sum rule method and Lanczos response function method ...

Finding And Analyzing U235 And U238 Ternary Fission Events In The Niffte Fissiontpc, Gabriel A. Oman

Physics

In this analysis, the differences between ternary and binary fission were explored using data from the NIFFTE Collaboration’s fission time projection chamber (TPC). The ratio of binary-to-ternary events for U-235 and U-238 as a function of neutron kinetic energy in the range of 1-30 MeV is presented. The typical value of the ratio is approximately 105 binary fissions per ternary fission, in agreement with previously published measurements. Future work will involve distinguishing the fissions of the two isotopes to provide more insight into this rare process.

Thermodynamic Stabilities Of Perfect And Vacancy-Defected Li2 Tio3 (001) Surfaces From First-Principles Analyses, Yan Jiang, Yanli Shi, Xiaogang Xiang, Jianqi Qi, Yong Han, Zhijun Liao, Tiecheng Lu

Ames Laboratory Accepted Manuscripts

Lithium titanate (Li2TiO3) is an attractive ceramic material for various industrial applications, particularly as one of the most promising breeder blanket materials in future nuclear-fusion reactors. Previously reported studies mainly focus on sintered polycrystalline samples of Li2TiO3. Surface structure of the single-crystal form is rarely reported, although the information of surface structures and stabilities can be critical for further understanding the surface-associated processes. In this work, we perform extensive first-principles density-functional-theory (DFT) calculations to obtain the surface energies of Li2TiO3 (001) with different surface terminations. For four perfect (defect-free) Li-, O-, or LiTi-terminated (001) surfaces, Li- or O-terminated (001) surfaces ...

Developing Nucleon Self-Energies To Generate The Ingredients For The Description Of Nuclear Reactions, Mack Charles Atkinson

Arts & Sciences Electronic Theses and Dissertations

The nucleon self-energies of 40Ca, 48Ca, and 208Pb are determined using a

nonlocal dispersive optical model (DOM). By enforcing the dispersion relation

connecting the real and imaginary part of the self-energy, both experimental

scattering data and nuclear structure data are used to constrain these

self-energies. The ability to calculate both bound and scattering states

simultaneously puts these self-energies in a unique position to consistently

describe exclusive knockout reactions such as (e,e'p). Using the

well-constrained self-energy describing 40Ca, the distorted-wave impulse

approximation (DWIA) description of the (e,e'p) reaction is shown to be valid

for outgoing proton kinetic ...

Isotopically-Resolved Neutron Cross Sections As Probe Of The Nuclear Optical Potential, Cole Davis Pruitt

Arts & Sciences Electronic Theses and Dissertations

Neutron scattering experiments provide direct access to the forces experienced by nucleons in the nuclear environment. Due to the experimental difficulty of cross section measurements with neutrons, isotopically-resolved neutron scattering cross sections are sorely needed as inputs for many nuclear models. This dissertation presents the results from a campaign of isotope-specific neutron total cross section measurements on 16,18O, 58,64Ni, 112,124Sn, and 103Rh from 3-450 MeV and elastic scattering differential cross section measurements on 112,nat,124Sn at 11 and 17 MeV. Equipped with these new data and with computational improvements to the Dispersive Optical Model (DOM), we ...

Measurement Of Two-Particle Correlations With Respect To Second- And Third-Order Event Planes In Au + Au Collisions At √Snn=200 Gev, A. Adare, John C. Hill, Nels J. Hotvedt, Todd Kempel, John G. Lajoie, Alexandre Lebedev, S. H. Lee, Craig Ogilvie, Milap R. Patel, H. Pei, Timothy T. Rinn, Marzia Rosati, Jonathan C. Runchey, Alexey Yu. Semenov, M. Shimomura, Carla Vale, Feng Wei, Et Al., Phenix Collaboration

Physics and Astronomy Publications

We present measurements of azimuthal correlations of charged hadron pairs in root s(NN) = 200 GeV Au + Au collisions for the trigger and associated particle transverse-momentum ranges of 1 < p(T)(t) < 10 GeV/c and 0.5 < p(T)(a) < 10 GeV/c. After subtraction of an underlying event using a model that includes higher-order azimuthal anisotropy v(2), v(3,) and v(4), the away-side yield of the highest trigger-p(T)(p(T)(t) > 4 GeV/c) correlations is suppressed compared with that of correlations measured in p + p collisions. At the lowest associated particle p(T)(0.5 < p(T)(a) < 1 GeV/c), the away-side shape and yield are modified relative to those in p + p collisions. These observations are consistent with the scenario of radiative-jet energy loss. For the low-p(T) trigger correlations (2 < p(T)(t) < 4 GeV/c), a finite away-side yield exists and we explore the dependence of the shape of the away-side within the context of an underlying-event model. Correlations are also studied differentially versus event-plane angle Psi(2) and Psi(3). The angular correlations show an asymmetry when selecting the sign of the difference between the trigger-particle azimuthal angle and the Psi(2) event plane. This asymmetry and the measured suppression of the pair yield out-of-plane is consistent with a path-length-dependent energy loss. No Psi(3) dependence can be resolved within experimental uncertainties.