A5003809688- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Particle physics theoretical and experimental studies
- Nuclear physics research studies
- Advanced NMR Techniques and Applications
- Atomic and Subatomic Physics Research
- Cold Atom Physics and Bose-Einstein Condensates
- Advanced Chemical Physics Studies
- Physics of Superconductivity and Magnetism
- Pulsars and Gravitational Waves Research
- Atomic and Molecular Physics
- Quantum, superfluid, helium dynamics
- Superconducting Materials and Applications
- Isotope Analysis in Ecology
- Scientific Research and Discoveries
- Rare-earth and actinide compounds
- Molecular spectroscopy and chirality
- Particle accelerators and beam dynamics
- Particle Accelerators and Free-Electron Lasers
- Stochastic processes and statistical mechanics
- Quantum many-body systems
- Magnetic confinement fusion research
- Experimental and Theoretical Physics Studies
- Radiation Detection and Scintillator Technologies
- Superconductivity in MgB2 and Alloys
University of Georgia
2010-2022
Forschungszentrum Jülich
1984-2015
University College London
2014
George Washington University
2011
Kyungpook National University
2011
The University of Tokyo
1994
University of Chile
1992
Michigan State University
1986-1988
National Superconducting Cyclotron Laboratory
1988
Universidade de São Paulo
1981-1983
The recently discovered enhancement of eta photoproduction on the quasi-free neutron at energies around sqrt(s)~1.67 GeV is addressed within a SU(3) coupled channel model. cross sections proton and neutron, sigma_n sigma_p, can be quantitatively explained. In this study, main source for peak in sigma_n/sigma_p effect S-wave that explains dip-bump structure gamma n --> n. particular, photon coupling to intermediate meson-baryon states important. stability result extensively tested consistency...
Using one of the recent Bonn potentials, an energy- and density-dependent interaction for nucleon-nucleus scattering is derived by solving Bethe-Goldstone equation two nucleons interacting in presence infinite nuclear matter at several incident energies below 425 MeV. Some approximations involved construction effective are discussed its dynamical properties examined. Selected present also compared with those a similar G-matrix based on Paris potential as well t-matrix directly...
The charged and neutral pion photoproduction reactions are investigated in a dynamical coupled-channels approach based on the formulation of Haberzettl, Huang, Nakayama [Phys. Rev. C 83, 065502 (2011)]. hadronic final-state interaction is provided by J\"ulich $\ensuremath{\pi}N$ model, which includes channels $\ensuremath{\eta}N$ comprising stable hadrons as well effective $\ensuremath{\pi}\ensuremath{\pi}N$ $\ensuremath{\pi}\ensuremath{\Delta}$, $\ensuremath{\sigma}N$, $\ensuremath{\rho}N$....
The production of ${\ensuremath{\eta}}^{\ensuremath{'}}$ mesons in photon- and hadron-induced reactions has been revisited view the recent additions high-precision data to world base. Based on an effective Lagrangian approach, we performed a combined analysis free quasifree $\ensuremath{\gamma}N\ensuremath{\rightarrow}{\ensuremath{\eta}}^{\ensuremath{'}}N$, $NN\ensuremath{\rightarrow}NN{\ensuremath{\eta}}^{\ensuremath{'}}$,...
High energy photons may be produced in nuclear reactions by several mechanisms, including bremsstrahlung from the potential field or nucleon-nucleon collisions. Using infinite and semi-infinite matter approximations, we obtain simple expressions for rates. Nucleon-nucleon collisions provide more important mechanism both proton-induced heavy-ion induced reactions, except highest photons. The photon cross section calculated with a zero range np interaction agrees well measurements on...
The isovector parts of the effective nucleon-nucleon interaction are studied by examination reaction $^{14}\mathrm{C}$(p,n) at intermediate energies near zero momentum transfer with use recently developed G-matrix and free--t-matrix interactions. spin-independent coupling (${V}_{\ensuremath{\tau}}$) exhibits a strong energy density dependence which, in case G matrix based on Bonn potential, significantly improves agreement between calculated values...
Quasi-free photoproduction of $\eta '$ mesons off nucleons bound in the deuteron has been measured with combined Crystal Barrel - TAPS detector. The experiment was done at a tagged photon beam ELSA electron accelerator Bonn for incident energies from production threshold up to 2.5 GeV. '$-mesons have detected coincidence recoil protons and neutrons. quasi-free proton data are good agreement results free protons, indicating that nuclear effects no significant impact. neutrons provides first...
The high-precision cross-section data for the reaction $\gamma p \to K^{*+}\Lambda$ reported by CLAS Collaboration at Thomas Jefferson National Accelerator Facility have been analyzed based on an effective Lagrangian approach in tree-level approximation. Apart from $t$-channel $K$, $\kappa$, $K^*$ exchanges, $s$-channel nucleon ($N$) exchange, $u$-channel $\Lambda$, $\Sigma$, $\Sigma^*(1385)$ and generalized contact term, contributions near-threshold resonances are also taken into account...
In the light baryon sector resonances can be broad and overlapping are in most cases not directly visible cross section data. Automatized model selection techniques that introduce penalties for used to determine minimally needed set of describe Several possible penalization schemes compared. As an application we perform a blindfold identification hyperon $\overline{K}N\ensuremath{\rightarrow}K\mathrm{\ensuremath{\Xi}}$ reaction based on least absolute shrinkage operator (LASSO) combination...
It is demonstrated that measurements of photon asymmetry in the γn→K−K+n reaction, can most likely determine parity newly discovered Θ+ pentaquark. We predict if positive, significantly positive; negative, negative. If background contribution large, may become very small magnitude, thereby making it difficult to distinguish between positive and negative results. However, even this case, a combined analysis (K+n) invariant mass distribution should allow determination Θ+.
Using a relativistic effective Lagrangian at the hadronic level, near-threshold $\ensuremath{\omega}$- and $\ensuremath{\varphi}$-meson productions in proton-proton $(\mathrm{pp})$ collisions, $p\stackrel{\ensuremath{\rightarrow}}{p}\mathrm{pp}\ensuremath{\omega}/\ensuremath{\varphi},$ are studied within distorted wave Born approximation. Both initial final state $\mathrm{pp}$ interactions included. In addition to total cross section data, both $\ensuremath{\omega}$ $\ensuremath{\varphi}$...
A field-theory-based approach to pion photoproduction off the nucleon is used derive a microscopically consistent formulation of fully dressed electromagnetic current in an effective Lagrangian formalism. It shown how rigorous implementation local gauge invariance at all levels reaction dynamics provides equations that lend themselves practically manageable truncations underlying nonlinearities problem. The requirement consistency also suggests novel way treating Guided by phenomenological...
The most recent high-precision data on spin observables $\mathrm{\ensuremath{\Sigma}}$, $T$, ${P}^{\ensuremath{'}}$, $E$, $F$, and $H$ reported by the CLAS Collaboration together with previous differential cross sections spin-density-matrix elements CLAS, A2, GRAAL, SAPHIR, CBELSA/TAPS Collaborations for reaction $\ensuremath{\gamma}p\ensuremath{\rightarrow}\ensuremath{\omega}p$ are analyzed within an effective Lagrangian approach. amplitude is constructed considering $t$-channel...
The most recent data on beam asymmetries, $\Sigma$, and beam-target $E$, from the CLAS Collaboration, together with previous differential cross sections asymmetries LEPS Collaborations, for $\gamma n \to K^+\Sigma^-$ reaction are studied based an effective Lagrangian approach in tree-level Born approximation. $t$-channel $K$ $K^\ast(892)$ exchanges, $u$-channel $\Sigma$ exchange, interaction current, exchanges of $N$, $\Delta$, their excited states $s$ channel considered constructing...
Measurements of spin-flip probabilities for inelastic scattering 318 MeV protons from $^{40}\mathrm{Ca}$ reveal that much the background underlying giant dipole and quadrupole resonances at small angles is \ensuremath{\Delta}S=1 transitions. This holds promise allowing a better estimate this than has previously been possible; one model-dependent parameter necessary. Subsequent analysis with first presented.