751 research outputs found
Inclusive quasielastic scattering of polarized electrons from polarized nuclei
The inclusive quasielastic response functions that appear in the scattering
of polarized electrons from polarized nuclei are computed and analyzed for
several closed-shell-minus-one nuclei with special attention paid to 39K.
Results are presented using two models for the ejected nucleon --- when
described by a distorted wave in the continuum shell model or by a plane wave
in PWIA with on- and off-shell nucleons. Relativistic effects in kinematics and
in the electromagnetic current have been incorporated throughout. Specifically,
the recently obtained expansion of the electromagnetic current in powers only
of the struck nucleon's momentum is employed for the on-shell current and the
effects of the first-order terms (spin-orbit and convection) are compared with
the zeroth-order (charge and magnetization) contributions. The use of polarized
inclusive quasielastic electron scattering as a tool for determining
near-valence nucleon momentum distributions is discussed.Comment: 51 LaTeX pages, 14 Postscript figure
Current Distribution in the Three-Dimensional Random Resistor Network at the Percolation Threshold
We study the multifractal properties of the current distribution of the
three-dimensional random resistor network at the percolation threshold. For
lattices ranging in size from to we measure the second, fourth and
sixth moments of the current distribution, finding {\it e.g.\/} that
where is the conductivity exponent and is the
correlation length exponent.Comment: 10 pages, latex, 8 figures in separate uuencoded fil
Remodeling the B-model
We propose a complete, new formalism to compute unambiguously B-model open
and closed amplitudes in local Calabi-Yau geometries, including the mirrors of
toric manifolds. The formalism is based on the recursive solution of matrix
models recently proposed by Eynard and Orantin. The resulting amplitudes are
non-perturbative in both the closed and the open moduli. The formalism can then
be used to study stringy phase transitions in the open/closed moduli space. At
large radius, this formalism may be seen as a mirror formalism to the
topological vertex, but it is also valid in other phases in the moduli space.
We develop the formalism in general and provide an extensive number of checks,
including a test at the orbifold point of A_p fibrations, where the amplitudes
compute the 't Hooft expansion of Wilson loops in lens spaces. We also use our
formalism to predict the disk amplitude for the orbifold C^3/Z_3.Comment: 83 pages, 9 figure
Nuclear Skins and Halos in the Mean-Field Theory
Nuclei with large neutron-to-proton ratios have neutron skins, which manifest
themselves in an excess of neutrons at distances greater than the radius of the
proton distribution. In addition, some drip-line nuclei develop very extended
halo structures. The neutron halo is a threshold effect; it appears when the
valence neutrons occupy weakly bound orbits. In this study, nuclear skins and
halos are analyzed within the self-consistent Skyrme-Hartree-Fock-Bogoliubov
and relativistic Hartree-Bogoliubov theories for spherical shapes. It is
demonstrated that skins, halos, and surface thickness can be analyzed in a
model-independent way in terms of nucleonic density form factors. Such an
analysis allows for defining a quantitative measure of the halo size. The
systematic behavior of skins, halos, and surface thickness in even-even nuclei
is discussed.Comment: 22 RevTeX pages, 22 EPS figures included, submitted to Physical
Review
Electron Energy-Loss Spectroscopy and Energy-Filtered TEM Imaging for the in situ Assessment of Reduction-Oxidation Reactions in Ni-Based Solid Oxide Fuel Cells
Time-Independent Gravitational Fields
This article reviews, from a global point of view, rigorous results on time
independent spacetimes. Throughout attention is confined to isolated bodies at
rest or in uniform rotation in an otherwise empty universe. The discussion
starts from first principles and is, as much as possible, self-contained.Comment: 47 pages, LaTeX, uses Springer cl2emult styl
Planck 2015 results. XXVII. The Second Planck Catalogue of Sunyaev-Zeldovich Sources
We present the all-sky Planck catalogue of Sunyaev-Zeldovich (SZ) sources detected from the 29 month full-mission data. The catalogue (PSZ2) is the largest SZ-selected sample of galaxy clusters yet produced and the deepest all-sky catalogue of galaxy clusters. It contains 1653 detections, of which 1203 are confirmed clusters with identified counterparts in external data-sets, and is the first SZ-selected cluster survey containing > confirmed clusters. We present a detailed analysis of the survey selection function in terms of its completeness and statistical reliability, placing a lower limit of 83% on the purity. Using simulations, we find that the Y5R500 estimates are robust to pressure-profile variation and beam systematics, but accurate conversion to Y500 requires. the use of prior information on the cluster extent. We describe the multi-wavelength search for counterparts in ancillary data, which makes use of radio, microwave, infra-red, optical and X-ray data-sets, and which places emphasis on the robustness of the counterpart match. We discuss the physical properties of the new sample and identify a population of low-redshift X-ray under- luminous clusters revealed by SZ selection. These objects appear in optical and SZ surveys with consistent properties for their mass, but are almost absent from ROSAT X-ray selected samples
Apolipoprotein E epsilon 4 (APOE-ε4) genotype is associated with decreased 6-month verbal memory performance after mild traumatic brain injury
Introduction: The apolipoprotein E (APOE) ε4 allele associates with memory impairment in neurodegenerative diseases. Its association with memory after mild traumatic brain injury (mTBI) is unclear. Methods: mTBI patients (Glasgow Coma Scale score 13–15, no neurosurgical intervention, extracranial Abbreviated Injury Scale score ≤1) aged ≥18 years with APOE genotyping results were extracted from the Transforming Research and Clinical Knowledge in Traumatic Brain Injury Pilot (TRACK-TBI Pilot) study. Cohorts determined by APOE-ε4(+/−) were assessed for associations with 6-month verbal memory, measured by California Verbal Learning Test, Second Edition (CVLT-II) subscales: Immediate Recall Trials 1–5 (IRT), Short-Delay Free Recall (SDFR), Short-Delay Cued Recall (SDCR), Long-Delay F
Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment
This paper describes an analysis of the angular distribution of W->enu and
W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with
the ATLAS detector at the LHC in 2010, corresponding to an integrated
luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and
the missing transverse energy, the W decay angular distribution projected onto
the transverse plane is obtained and analysed in terms of helicity fractions
f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV
and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw
> 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour,
are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017
+/- 0.030, where the first uncertainties are statistical, and the second
include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables,
revised author list, matches European Journal of Physics C versio
Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS
The chi_b(nP) quarkonium states are produced in proton-proton collisions at
the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS
detector. Using a data sample corresponding to an integrated luminosity of 4.4
fb^-1, these states are reconstructed through their radiative decays to
Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks
corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new
structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is
also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes.
This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table,
corrected author list, matches final version in Physical Review Letter
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