77 research outputs found
The f_LT Response Function of D(e,e'p)n at Q^2=0.33(GeV/c)^2
The interference response function f_LT (R_LT) of the D(e,e'p)n reaction has
been determined at squared four-momentum transfer Q^2 = 0.33 (GeV/c)^2 and for
missing momenta up to p_miss= 0.29 (GeV/c). The results have been compared to
calculations that reproduce f_LT quite well but overestimate the cross sections
by 10 - 20% for missing momenta between 0.1 (GeV/c) and 0.2 (GeV/c) .Comment: 12 Pages, 10 figure
SARS-CoV-2 virus outbreak and the emergency public health measures in Bosnia and Herzegovina: January – july 2020
Between March 5th and July 25th, 2020, the total number of SARS-CoV-2 confirmed cases in Bosnia and Herzegovina (BH) was 10,090, corresponding to a cumulative incidence rate of 285.7/100,000 population. Demographic and clinical information on all the cases along with exposure and contact information were collected using a standardized case report form. In suspected SARS-CoV-2 cases, respiratory specimens were collected and tested by real-time reverse-transcriptase polymerase chain reaction assay. The dynamic of the outbreak was summarized using epidemiolog
Virtual Compton Scattering and the Generalized Polarizabilities of the Proton at Q^2=0.92 and 1.76 GeV^2
Virtual Compton Scattering (VCS) on the proton has been studied at Jefferson
Lab using the exclusive photon electroproduction reaction (e p --> e p gamma).
This paper gives a detailed account of the analysis which has led to the
determination of the structure functions P_LL-P_TT/epsilon and P_LT, and the
electric and magnetic generalized polarizabilities (GPs) alpha_E(Q^2) and
beta_M(Q^2) at values of the four-momentum transfer squared Q^2= 0.92 and 1.76
GeV^2. These data, together with the results of VCS experiments at lower
momenta, help building a coherent picture of the electric and magnetic GPs of
the proton over the full measured Q^2-range, and point to their non-trivial
behavior.Comment: version 2: modified according to PRC Editor's and Referee's
recommendations. Archival paper for the E93-050 experiment at JLab Hall A. 28
pages, 23 figures, 5 cross-section tables. To be submitted to Phys.Rev.
The reaction dynamics of the 16O(e,e'p) cross section at high missing energies
We measured the cross section and response functions (R_L, R_T, and R_LT) for
the 16O(e,e'p) reaction in quasielastic kinematics for missing energies 25 <=
E_miss <= 120 MeV at various missing momenta P_miss <= 340 MeV/c. For 25 <
E_miss < 50 MeV and P_miss \approx 60 MeV/c, the reaction is dominated by
single-nucleon knockout from the 1s1/2-state. At larger P_miss, the
single-particle aspects are increasingly masked by more complicated processes.
For E_miss > 60 MeV and P_miss > 200 MeV/c, the cross section is relatively
constant. Calculations which include contributions from pion exchange currents,
isobar currents and short-range correlations account for the shape and the
transversity but only for half of the magnitude of the measured cross section.Comment: 6 pages, 4 figures, submitted to Phys Rev Lett, formatting error
fixe
Backward electroproduction of pi0 mesons on protons in the region of nucleon resonances at four momentum transfer squared Q**2 = 1.0 GeV**2
Exclusive electroproduction of pi0 mesons on protons in the backward
hemisphere has been studied at Q**2 = 1.0 GeV**2 by detecting protons in the
forward direction in coincidence with scattered electrons from the 4 GeV
electron beam in Jefferson Lab's Hall A. The data span the range of the total
(gamma* p) center-of-mass energy W from the pion production threshold to W =
2.0 GeV. The differential cross sections sigma_T+epsilon*sigma_L, sigma_TL, and
sigma_TT were separated from the azimuthal distribution and are presented
together with the MAID and SAID parametrizations.Comment: 17 pages, 11 figures, information can be found at
http://hallaweb.jlab.org/experiment/E93-050/vcs.html updated content about
SAID analysis updated MAID results following new reference nucl-th/0310041
updated figure
Large Momentum Transfer Measurements of the Deuteron Elastic Structure Function A(Q^2) at Jefferson Laboratory
The deuteron elastic structure function A(Q^2) has been extracted in the Q^2
range 0.7 to 6.0 (GeV/c)^2 from cross section measurements of elastic
electron-deuteron scattering in coincidence using the Hall A Facility of
Jefferson Laboratory. The data are compared to theoretical models based on the
impulse approximation with inclusion of meson-exchange currents, and to
predictions of quark dimensional scaling and perturbative quantum
chromodynamicsComment: Submitted to Physical Review Letter
Display of probability densities for data from a continuous distribution
Based on cumulative distribution functions, Fourier series expansion and
Kolmogorov tests, we present a simple method to display probability densities
for data drawn from a continuous distribution. It is often more efficient than
using histograms.Comment: 5 pages, 4 figures, presented at Computer Simulation Studies XXIV,
Athens, GA, 201
Virtual Compton Scattering and Neutral Pion Electroproduction in the Resonance Region up to the Deep Inelastic Region at Backward Angles
We have made the first measurements of the virtual Compton scattering (VCS)
process via the H exclusive reaction in the nucleon resonance
region, at backward angles. Results are presented for the -dependence at
fixed GeV, and for the -dependence at fixed near 1.5 GeV.
The VCS data show resonant structures in the first and second resonance
regions. The observed -dependence is smooth. The measured ratio of
H to H cross sections emphasizes the different
sensitivity of these two reactions to the various nucleon resonances. Finally,
when compared to Real Compton Scattering (RCS) at high energy and large angles,
our VCS data at the highest (1.8-1.9 GeV) show a striking -
independence, which may suggest a transition to a perturbative scattering
mechanism at the quark level.Comment: 20 pages, 8 figures. To appear in Phys.Rev.
Polygenic Risk Scores for Developmental Disorders, Neuromotor Functioning During Infancy, and Autistic Traits in Childhood
Background: Impaired neuromotor development is often one of the earliest observations in children with autism spectrum disorder (ASD). We investigated whether a genetic predisposition to developmental disorders was associated with nonoptimal neuromotor development during infancy and examined the genetic correlation between nonoptimal neuromotor development and autistic traits in the general population. Methods: In a population-based cohort in The Netherlands (2002–2006), we calculated polygenic risk scores (PRSs) for ASD and attention-deficit/hyperactivity disorder (ADHD) using genome-wide association study summary statistics. In 1921 children with genetic data, parents rated autistic traits at 6 years of age. Among them, 1174 children (61.1%) underwent neuromotor examinations (tone, responses, senses, and other observations) during infancy (9–20 weeks of age). We used linear regressions to examine associations of PRSs with neuromotor scores and autistic traits. We performed a bivariate genome-based restricted maximum likelihood analysis to explore whether genetic susceptibility underlies the association between neuromotor development and autistic traits. Results: Higher PRSs for ASD were associated with less optimal overall infant neuromotor development, in particular low muscle tone. Higher PRSs for ADHD were associated with less optimal senses. PRSs for ASD and those for ADHD both were associated with autistic traits. The single nucleotide polymorphism–based heritability of overall motor development was 20% (SE = .21) and of autistic traits was 68% (SE = .26). The genetic correlation between overall motor development and autistic traits was .35 (SE = .21, p < .001). Conclusions: We found that genetic liabilities for ASD and ADHD covary with neuromotor development during infancy. Shared genetic liability might partly explain the association between nonoptimal neuromotor development during infancy and autistic traits in childhood
Dynamics of the O(e,e'p) cross section at high missing energies
We measured the cross section and response functions (R_L, R_T, and R_LT) for the 16O(e,e'p) reaction in quasielastic kinematics for missing energies 25 60 MeV and P_miss > 200 MeV/c, the cross section is relatively constant. Calculations which include contributions from pion exchange currents, isobar currents and short-range correlations account for the shape and the transversity but only for half of the magnitude of the measured cross section
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