A5026253367- Nuclear physics research studies
- Nuclear Physics and Applications
- High-Energy Particle Collisions Research
- Nuclear reactor physics and engineering
- Astronomical and nuclear sciences
- Atomic and Molecular Physics
- Quantum Chromodynamics and Particle Interactions
- X-ray Spectroscopy and Fluorescence Analysis
- Advanced Chemical Physics Studies
- Radiation Detection and Scintillator Technologies
- Particle physics theoretical and experimental studies
- Ion-surface interactions and analysis
- Astro and Planetary Science
- Nuclear Materials and Properties
- Quantum, superfluid, helium dynamics
- Particle Detector Development and Performance
- Gamma-ray bursts and supernovae
- Radiopharmaceutical Chemistry and Applications
- Particle accelerators and beam dynamics
- High-pressure geophysics and materials
- Mass Spectrometry Techniques and Applications
- Statistical Mechanics and Entropy
- Electron and X-Ray Spectroscopy Techniques
- Atomic and Subatomic Physics Research
- X-ray Diffraction in Crystallography
Texas A&M University
2016-2025
Mitchell Institute
2003-2025
Indiana University Bloomington
1990-2022
Kyoto University
2021
College Station Medical Center
2020
Los Alamos National Laboratory
2009
Institute of Chemistry of the Slovak Academy of Sciences
2009
Slovak Academy of Sciences
2009
Welch Foundation
2007
Michigan State University
1991-2001
The symmetry energy contribution to the nuclear equation of state impacts various phenomena in astrophysics, structure, and reactions. Its determination is a key objective contemporary physics, with consequences for understanding dense matter within neutron stars. We examine results laboratory experiments that have provided initial constraints on its density dependence at somewhat below normal density. Even though some these been derived from properties nuclei while others response...
Directed and elliptic flows of neutrons light charged particles were measured for the reaction 197Au+197Au at 400 MeV/nucleon incident energy within ASY-EOS experimental campaign GSI laboratory. The detection system consisted Large Area Neutron Detector LAND, combined with parts CHIMERA multidetector, ALADIN Time-of-flight Wall, Washington-University Microball detector. latter three arrays used event characterization reaction-plane reconstruction. In addition, an array triple telescopes,...
Many neutron star properties, such as the proton fraction, reflect symmetry energy contributions to equation of state that dominate when and densities differ strongly. To constrain these at suprasaturation densities, we measure spectra charged pions produced by colliding rare isotope tin (Sn) beams with isotopically enriched Sn targets. Using ratios pion measured high transverse momenta, deduce slope be $42<L<117\text{ }\text{ }\mathrm{MeV}$. This value is slightly lower but consistent $L$...
The density dependence of the symmetry energy in equation state isospin asymmetric nuclear matter is significant importance for studying structure systems as diverse neutron-rich nuclei and neutron stars. A number reactions using dynamical statistical models multifragmentation, experimental isoscaling observable, are studied to extract information on energy. It observed that model calculations give consistent results assuming sequential decay effect be small. comparison with several other...
The disappearance of collective flow in nucleus-nucleus collisions occurs at an incident energy (${\mathit{E}}_{\mathrm{bal}}$) where the attractive scattering dominant low energies balances repulsive high energies. We have performed first systematic study entrance-channel mass dependence and hence ${\mathit{E}}_{\mathrm{bal}}$. new data presented for C+C, Ne+Al, Ar+Sc, Kr+Nb systems show that ${\mathit{E}}_{\mathrm{bal}}$ scales as ${\mathit{A}}^{\mathrm{\ensuremath{-}}1/3}$ A is combined...
The thermal component of the 8 GeV/c pi+ Au data ISiS Collaboration is shown to follow scaling predicted by Fisher's model when Coulomb energy taken into account. Critical exponents tau and sigma, critical point (p(c),rho(c),T(c)), surface coefficient c(0), enthalpy evaporation DeltaH, compressibility factor C(F)(c) are determined. For first time, experimental phase diagrams, (p,T) (T,rho), describing liquid vapor coexistence finite neutral nuclear matter have been constructed.
In the past two decades, pions created in high density regions of heavy ion collisions have been predicted to be sensitive at densities symmetry energy term nuclear equation state, a property that is key our understanding neutron stars. new experiment designed study energy, multiplicities negatively and positively charged measured with accuracy for central 132Sn+124Sn, 112Sn+124Sn, 108Sn+112Sn E/A=270 MeV SπRIT Time Projection Chamber. While individual pion are 4% accuracy, those...
Within the framework of an isospin-dependent Boltzmann-Uehling-Uhlenbeck model using initial proton and neutron densities calculated from nonlinear relativistic mean-field theory, we compare strength transverse collective flow in reactions ${}^{48}\mathrm{Ca}{+}^{58}\mathrm{Fe}$ ${}^{48}\mathrm{Cr}{+}^{58}\mathrm{Ni}$, which have same mass number but different neutron/proton ratios. The neutron-rich system ( ${}^{48}\mathrm{Ca}{+}^{58}\mathrm{Fe}$) is found to show significantly stronger...
Collective transverse flow of nuclear matter was measured as a function the ratio neutrons to protons ( $N/Z$) interacting system for first time. The collisions three isotopically pure beams $A\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}58\mathrm{nuclei}$ with two $A\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}58\mathrm{targets}$ were studied at 55 MeV/nucleon. results variables demonstrate sensitivity transport models elementary aspects nucleon-nucleon collisions.
The energy at which collective transverse flow in the reaction plane disappears, balance ${E}_{\mathrm{bal}}$, is found to depend on isospin of system using reactions ${}^{58}\mathrm{Fe}{+}^{58}\mathrm{Fe}$ and ${}^{58}\mathrm{Ni}{+}^{58}\mathrm{Ni}$. more neutron-rich exhibits higher energies for all measured impact parameters, agreement with predictions a transport model incorporates an dependent mean field in-medium nucleon-nucleon cross sections.
The density dependence of the symmetry energy in equation state isospin asymmetric nuclear matter is studied using isoscaling fragment yields and antisymmetrized molecular dynamic calculation. It observed that experimental data at low densities are consistent with form energy, ${\mathrm{E}}_{\mathrm{sym}}\ensuremath{\approx}31.6(\ensuremath{\rho}/{\ensuremath{\rho}}_{○}){}^{0.69}$, close agreement those predicted by results variational many-body A comparison present result reported recently...
An extensive experimental survey of the features disassembly a small quasiprojectile system with $A~36$, produced in reactions 47 MeV/nucleon $^{40}\mathrm{Ar}\phantom{\rule{0.3em}{0ex}}+\phantom{\rule{0.3em}{0ex}}^{27}\mathrm{Al}$, $^{48}\mathrm{Ti}$, and $^{58}\mathrm{Ni}$, has been carried out. Nuclei excitation energy range 1--9 have investigated employing new method to reconstruct source. At an \ensuremath{\sim}5.6 many observables indicate presence maximal fluctuations deexcitation...
Excitation-energy-gated two-fragment correlation functions have been studied between 2 to 9A MeV of excitation energy for equilibrium-like sources formed in $\pi^-$ and p + $^{197}$Au reactions at beam momenta 8,9.2 10.2 GeV/c. Comparison the data an N-body Coulomb-trajectory code shows a decrease one order magnitude fragment emission time interval 2-5A MeV, followed by nearly constant breakup higher energy. The observed is shown be strongly correlated with increase probability, onset...
Momentum spectra have been measured for the reaction $^{11}\mathrm{B}$${(}^{7}$Li${,}^{8}$B${)}^{10}$Li at 130 MeV and laboratory angles of 5\ifmmode^\circ\else\textdegree\fi{} 3.5\ifmmode^\circ\else\textdegree\fi{}. There is strong evidence existence a broad state in unstable nucleus $^{10}\mathrm{Li}$, corresponding to single p-wave neutron resonance unbound decay by 538\ifmmode\pm\else\textpm\fi{}62 keV with wdith...
The quasielastic scattering of the exotic ``halo'' nucleus $^{11}\mathrm{Li}$ on $^{12}\mathrm{C}$ has been studied at an energy 60 MeV/nucleon and compared with that A=11 isobar $^{11}\mathrm{C}$. prediction enhanced refraction in former system is confirmed, as need for very long-range absorption. No evidence found Airy minimum far-side scattering.
We have measured two-fragment reduced-velocity correlation functions of the intermediate mass fragments (IMF: 3\ensuremath{\le}Z\ensuremath{\le}7) produced in multifragment final states for Kr+Nb system (E/A=35, 45, 55, 65, and 75 MeV). From we extract mean IMF emission lifetimes (\ensuremath{\tau}) which are observed to decrease from \ensuremath{\tau}\ensuremath{\approxeq}400 fm/c at E/A=35 MeV \ensuremath{\tau}\ensuremath{\approxeq}125 E/A=55 MeV. For beam energies excess MeV, no further...
The reaction systems, $^{64}\mathrm{Zn}+^{58}\mathrm{Ni}$, $^{64}\mathrm{Zn}+^{92}\mathrm{Mo}$, $^{64}\mathrm{Zn}+^{197}\mathrm{Au}$, at 26, 35, and $47\phantom{\rule{0.2em}{0ex}}A\phantom{\rule{0.3em}{0ex}}\text{MeV}$, have been studied both in experiments with a $4\ensuremath{\pi}$ detector array, NIMROD, antisymmetrized molecular dynamics model calculations employing effective interactions corresponding to soft stiff equation of state (EOS). Direct experimental observables, such as...
The transverse flow and relative midrapidity yield of isotopically identified light charged particles (LCPs) has been examined for the 35 MeV/nucleon ${}^{70}\mathrm{Zn}+{}^{70}\mathrm{Zn}$, ${}^{64}\mathrm{Zn}+{}^{64}\mathrm{Zn}$, ${}^{64}\mathrm{Ni}+{}^{64}\mathrm{Ni}$ systems. A large enhancement LCPs was observed to near projectile rapidity. In particular, this increased more neutron-rich demonstrating a preference production fragments in region. Additionally, extracted, which provides...
We study neutron-proton equilibration in dynamically deformed atomic nuclei created nuclear collisions. The two ends of the elongated nucleus are initially dissimilar composition and equilibrate on a subzeptosecond time scale following first-order kinetics. use angular momentum to relate breakup orientation breakup. extracted rate constant is 3 zs^{-1}, which corresponds mean 0.3 zs. This technique enables new insight into equation state that governs many astrophysical phenomena leading...