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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 865 records · Page 48
All sourcesNASA NTRSDOE OSTI
DOE OSTI2011

Diffractive heavy quark production in AA collisions at the LHC at NLO

The single and double diffractive cross sections for heavy quarks production are evaluated at NLO accuracy for hadronic and heavy ion collisions at the LHC. Diffractive charm and bottom production is the main subject of this work, providing predictions for CaCa, PbPb and pPb collisions. The hard diffraction formalism is considered using the Ingelman-Schlein model where a recent parametrization for the Pomeron structure function (DPDF) is applied. Absorptive corrections are taken into account as well. The diffractive ratios are estimated and theoretical uncertainties are discussed. Comparison with competing production channels is also presented.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Gamow-Teller Transitions Starting from T{sub z} = +3/2 Nucleus {sup 47}Ti

Gamow-Teller (GT) transitions are mediated by the {sigma}{tau} operator. Owing to its simplicity and also its spin-isospin nature, GT transitions play key roles in the studies of nuclear structure as well as astro-nuclear processes. In violent neutrino-induced reactions at the core-collapse stage of type II supernovae, Gamow-Teller (GT) transitions starting from stable as well as unstable pf-shell nuclei play important roles. We study GT transitions starting from {sup 47}Ti in a high-resolution ({sup 3}He,t) charge-exchange reactions at 0 deg. and at an intermediate incident energy of 140 MeV/nucleon at Research Center for Nuclear Physics (RCNP), Osaka. Individual GT transitions up to high excitations were observed. Assuming the isospin symmetry for the strengths of T{sub z} = {+-}3/2{yields}{+-}1/2 analogous GT transitions, we can deduce the detailed strength distribution starting from mirror unstable nucleus {sup 47}Mn.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2011

Suppression of alpha formation probability around the N = 126 shell closure

{alpha} formation amplitudes extracted from experimental data are presented and an abrupt change around the N = 126 shell closure is noted. It is explained as a sudden hindrance of the clustering of nucleons. The clustering induced by the pairing mode acting upon the four nucleons is inhibited if the configuration space does not allow a proper manifestation of the pairing collectivity.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2011

Gamow-Teller Transitions Starting from T{sub z} = +3/2 Nucleus {sup 45}Sc

Owing to its simplicity and also its nature of spin-isospin ({sigma}{tau}) excitation, Gamow-Teller (GT) transitions play key roles in the studies of nuclear structure as well as astro-nuclear processes. We studied GT transitions starting from {sup 45}Sc in a high-resolution ({sup 3}He,t) charge-exchange reactions at 0 deg. and at an intermediate incoming energy of 140 MeV/nucleon. Individual GT transitions were observed up to high excitation energy of 10 MeV and a concentration of GT strength, a resonance-like structure, was observed at 6.5 MeV.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2011

Statistical approach of parton distributions: a closer look at the high-xregion

We recall the physical features of the parton distributions in the quantum statistical approach of the nucleon, which allows to describe simultaneously, unpolarized and polarized Deep Inelastic Scattering data. Some predictionsfrom a next-to-leading order QCD analysis are compared to recent experimental results and we stress the importance of some tests in the high-x region, to confirm the validity of this approach.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Analyses of {pi}{sup {+-}-40}Ca Elastic Scattering Data in the Delta Resonance Region using Inverse Scattering Theory and the Klein-Gordon Equation

The elastic scattering cross sections for {pi}{sup +} by {sup 40}Ca have been analyzed, for the first time, using the Klein-Gordon (KG) equation that incorporates the Coulomb interaction between the charged pions and targets explicitly for the incident energies of 163.3 and 180 MeV. The nuclear part of the potentials is determined using an inverse scattering theory as a guide. Our results are then compared to those where the Coulomb potential has not been explicitly included in the KG equation but its effect is studied by modifying the incident kinetic energy following the prescription of Stricker. Our calculations that include the Coulomb potential in the KG equation reproduce the results using the Stricker prescription for {pi}{sup +}. The Stricker method is then used to calculate {pi}{sup -} scattering. In all cases, the data have been well accounted for.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Coherent {pi}{sup 0}-photoproduction on the deuteron including polarization observables

Coherent {pi}{sup 0}-photoproduction on the deuteron including polarization effects in the energy region from {pi}-threshold up to 1 GeV is studied using an enhanced elementary pion photo-production operator on the free nucleon and a realistic NN potential model for the deuteron wave function. Results for double polarization observables are predicted for which the sensitivity to various models for the elementary pion photoproduction amplitude is investigated. We find considerable dependence of the results on the elementary amplitude. In addition, results for differential cross section are predicted and compared with the experimental data from TAPS and a satisfactory agreement was found.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

An Overview on Muon Physics

A summary of the present status of the charged lepton flavor violation search with muons is presented. The relevant measurements (g-2){sub {mu}}, the {mu} {sup +}{yields} e{sup +} {gamma} decay and the direct muon-to-electron conversion projects are briefly reviewed.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Physics Potential of a 2540 Km Baseline Superbeam Experiment

We study the physics potential of a neutrino superbeam experiment with a 2540 km baseline. We assume a neutrino beam similar to the NuMI beam in the medium energy configuration. We consider a 100 kton totally active scintillator detector at a 7 mr off-axis location. We find that such a configuration has an outstanding hierarchy discriminating capability. In conjunction with the data from the present reactor neutrino experiments, it can determine the neutrino mass hierarchy at the 3{sigma} level in less than 5 years, if sin{sup 2}2{theta}{sub 13}{>=}0.01, running in the neutrino mode alone. As a stand alone experiment, with a 5 year neutrino run and a 5 year anti-neutrino run, it can determine non-zero {theta}{sub 13} at the 3{sigma} level if sin{sup 2} 2{theta}{sub 13}{>=}7x10{sup -3} and hierarchy at the 3{sigma} level if sin{sup 2}2{theta}{sub 13}{>=}8x10{sup -3}. This data can also distinguish {delta}{sub CP} = {pi}/2 from the CP conserving values of 0 and {pi}, for sin{sup 2}2{theta}{sub 13}{>=}0.02.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Monte Carlo Event Generators

Every neutrino experiment requires a Monte Carlo event generator for various purposes. Historically, each series of experiments developed their own code which tuned to their needs. Modern experiments would benefit from a universal code (e.g. PYTHIA) which would allow more direct comparison between experiments. GENIE attempts to be that code. This paper compares most commonly used codes and provides some details of GENIE.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

The MINERvA Experiment

The MINERvA experiment is a dedicated cross-section experiment whose aim is to measure neutrino cross sections for inclusive and exclusive final states on several nuclei. The detector is fully commissioned and began running in March 2010. As a dedicated cross-section experiment, MINERvA has a particular need to know the incident neutrino flux: both the absolute level and the energy dependence. In these proceedings we describe the MINERvA detector, give an update on the experimental status, and discuss the means to determine the neutrino flux.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2011

Recent Results from the WASA-at-COSY Experiment

Studies of light meson decays are the key experiments for the WASA detector at COSY-Juelich. One of the world largest data samples of the {eta} meson decays have been recently collected in the pd {yields}{sup 3}He{eta} and in the pp {yields} pp{eta} reactions. The status of the analysis of various decay channels and the further plans for the light meson decay program are presented.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

The Quark-Meson Coupling model as a description of dense matter

Quantum Hadrodynamics provides a useful framework for investigating dense matter, yet it breaks down easily when strangeness carrying baryons are introduced into the calculations, as the baryon effective masses become negative due to large meson field potentials. The Quark-Meson Coupling model overcomes this issue by incorporating the quark structure of the nucleon, thus allowing for a feedback between the the nuclei and the interaction with the meson fields. With the inclusion of this feature, QMC provides a successful description of finite nuclei and nuclear matter. We present the latest parameterization of QMC and discuss the predictions for dense nuclear matter and 'neutron' stars.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Recent results on SIDIS from pion production at CLAS

Novel view on QCD dynamics inside hadrons is offered by the transverse momentum dependent parton distributions and fragmentation functions. They can be accessed in Semi-Inclusive Deep Inelastic Scattering (SIDIS) experiments. Recent results on SIDI S from pion production at CLAS is presented in this talk.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2011

A measurement of double spin asymmetry A{sub LT} in semi-inclusive pion electroproduction on a transversely polarized {sup 3}He target

The double spin asymmetry A{sub LT} for {sup 3}He was measured for the first time at Jefferson Lab Hall A in the semi-inclusive {sup 3}He{up_arrow}({sup {yields}e},{pi}{sup +/-}X reactions, using a 6 GeV polarized electron beam on a transversely polarized {sup 3}He target. The produced charged pions were detected in coincidence with the scattered electrons by the high-resolution spectrometer and the BigBite spectrometer, respectively. The kinematic coverage was focused on the valence quark region, x {approx} 0.13-0.41, Q{sup 2}{approx} 1.31-3.10 (GeV/c){sup 2}. When combined with the world data, this new data will provide constraints on the g{sub 1T}{sup q} distribution functions, which describe the longitudinal polarization of quarks in a transversely polarized nucleon. The status of the current analysis and the preliminary results are presented.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

The Charmonium-molecule hybrid structure of the X(3872)

We propose that the X(3872) has the charmonium and the DD*-bar hadronic molecule hybrid structure. We study the structure of the X(3872) using the schematic model with the separable interaction. The strengths of the couplings between the charmonium state and the hadronic molecule states are determined so as to reproduce the observed mass of the the X(3872). The isospin symmetry breaking is introduced by the mass differences of the neutral and charged D mesons. The obtained structure of the X(3872) is about 9% of cc-bar charmonium, 75% of the isoscalar DD*-bar molecule and 16percent; of the isovector DD*-bar molecule which explains observed properties of the X(3872) well.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗