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

Measurement of Rlt and Atl in the 4He(e,e'p)3H Reaction at pmiss of 130-300 MeV/c

We have measured the 4He(e,e'p)3H reaction at missing momenta of 130-300 MeV/c using the three-spectrometer facility at the Mainz microtron MAMI. Data were taken in perpendicular kinematics to allow us to determine the response function Rlt and the asymmetry term Atl. The data are compared to both relativistic and non-relativistic calculations.Comment: To be published in the European Physical Journal

High-precision Studies of the 3^{\bf{3}}He(e,e′^{\bf{\prime}}p) Reaction at the Quasielastic Peak

Precision studies of the reaction $^{3}$He(e,e$^\prime$p) using the three-spectrometer facility at the Mainz microtron MAMI are presented. All data are for quasielastic kinematics at $|\vec{q} | =685$ MeV/c. Absolute cross sections were measured at three electron kinematics. For the measured missing momenta range from 10 to 165 MeV/c, no strength is observed for missing energies higher than 20 MeV. Distorted momentum distributions were extracted for the two-body breakup and the continuum. The longitudinal and transverse behavior was studied by measuring the cross section for three photon polarizations. The longitudinal and transverse nature of the cross sections is well described by a currently accepted and widely used prescription of the off-shell electron-nucleon cross-section. The results are compared to modern three-body calculations and to previous data.Comment: 4 pages, 3 figures. Submitted for publication in Phys. Rev. Let

What factors influence training opportunities for older workers? Three factorial surveys exploring the attitudes of HR professionals

The core research questions addressed in this paper are: what factors influence HR professionals in deciding whether to approve training proposals for older workers? What kind of training are they more likely to recommend for older employees and in which organizational contexts? We administered three factorial surveys to 66 HR professionals in Italy. Participants made specific training decisions based on profiles of hypothetical older workers. Multilevel analyses indicated that access to training decreases strongly with age, while highly-skilled older employees with low absenteeism rates are more likely to enjoy training opportunities. In addition, older workers displaying positive performance are more likely to receive training than older workers who perform poorly, suggesting that training late in working life may serve as a reward for good performance rather than as a means of enhancing productivity. The older the HR professional evaluating training proposals, the higher the probability that older workers will be recommended for training. keywords: training; older workers; HR professionals; factorial survey; multilevel model

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

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.

Consistent alpha-cluster description of the 12C (0^+_2) resonance

The near-threshold 12C (0^+_2) resonance provides unique possibility for fast helium burning in stars, as predicted by Hoyle to explain the observed abundance of elements in the Universe. Properties of this resonance are calculated within the framework of the alpha-cluster model whose two-body and three-body effective potentials are tuned to describe the alpha - alpha scattering data, the energies of the 0^+_1 and 0^+_2 states, and the 0^+_1-state root-mean-square radius. The extremely small width of the 0^+_2 state, the 0_2^+ to 0_1^+ monopole transition matrix element, and transition radius are found in remarkable agreement with the experimental data. The 0^+_2-state structure is described as a system of three alpha-particles oscillating between the ground-state-like configuration and the elongated chain configuration whose probability exceeds 0.9

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

The ratio of proton's electric to magnetic form factors measured by polarization transfer

The ratio of the proton's elastic electromagnetic form factors was obtained by measuring the transverse and longitudinal polarizations of recoiling protons from the elastic scattering of polarized electrons with unpolarized protons. The ratio of the electric to magnetic form factor is proportional to the ratio of the transverse to longitudinal recoil polarizations. The ratio was measured over a range of four-momentum transfer squared between 0.5 and 3.5 GeV-squared. Simultaneous measurement of transverse and longitudinal polarizations in a polarimeter provides good control of the systematic uncertainty. The results for the ratio of the proton's electric to magnetic form factors show a systematic decrease with increasing four momentum squared, indicating for the first time a marked difference in the spatial distribution of charge and magnetization currents in the proton.Comment: 5 pages, 2 figures, version of paper after corrections due to referees comments and shortened by removing one figure for Physical Review Letter

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