We report the measurement of beam-target double-spin asymmetries (\(A_\text{LT}\)) in the inclusive production of identified hadrons, \(\vec{e}~\)+\(~^3\text{He}^{\uparrow}\rightarrow h+X\), using a ...longitudinally polarized 5.9 GeV electron beam and a transversely polarized \(^3\rm{He}\) target. Hadrons (\(\pi^{\pm}\), \(K^{\pm}\) and proton) were detected at 16\(^{\circ}\) with an average momentum $<$$P_h$$>\(=2.35 GeV/c and a transverse momentum (\)p_{T}\() coverage from 0.60 to 0.68 GeV/c. Asymmetries from the \)^3\text{He}\( target were observed to be non-zero for \)\pi^{\pm}\( production when the target was polarized transversely in the horizontal plane. The \)\pi^{+}\( and \)\pi^{-}\( asymmetries have opposite signs, analogous to the behavior of \)A_\text{LT}$ in semi-inclusive deep-inelastic scattering.
Light and ultrastructural findings in a mixed mesodermal tumor of the urinary bladder are reported. The mesenchymal component of the tumor contained undifferentiated mesenchymal cells and cells with ...chondroblastic differentiation. The neoplastic chondrocytes displayed an abundance of cytoplasmic microfilaments and had a scalloped cell surface.
We report the first measurement of target single spin asymmetries of charged kaons produced in semi-inclusive deep inelastic scattering of electrons off a transversely polarized \(^3{\rm{He}}\) ...target. Both the Collins and Sivers moments, which are related to the nucleon transversity and Sivers distributions, respectively, are extracted over the kinematic range of 0.1$<$$x_{bj}$$<\(0.4 for \)K^{+}\( and \)K^{-}\( production. While the Collins and Sivers moments for \)K^{+}\( are consistent with zero within the experimental uncertainties, both moments for \)K^{-}\( favor negative values. The Sivers moments are compared to the theoretical prediction from a phenomenological fit to the world data. While the \)K^{+}\( Sivers moments are consistent with the prediction, the \)K^{-}$ results differ from the prediction at the 2-sigma level.
We report the first measurement of target single-spin asymmetries (A\(_N\)) in the inclusive hadron production reaction, \(e~\)+\(~^3\text{He}^{\uparrow}\rightarrow h+X\), using a transversely ...polarized \(^3\)He target. The experiment was conducted at Jefferson Lab in Hall A using a 5.9-GeV electron beam. Three types of hadrons (\(\pi^{\pm}\), \(\text{K}^{\pm}\) and proton) were detected in the transverse hadron momentum range 0.54 \(<p_T<\) 0.74 GeV/c. The range of \(x_F\) for pions was -0.29 \(<x_F<\) -0.23 and for kaons -0.25 \(<x_F<\)-0.18. The observed asymmetry strongly depends on the type of hadron. A positive asymmetry is observed for \(\pi^+\) and \(\text{K}^+\). A negative asymmetry is observed for \(\pi^{-}\). The magnitudes of the asymmetries follow \(|A^{\pi^-}| < |A^{\pi^+}| < |A^{K^+}|\). The K\(^{-}\) and proton asymmetries are consistent with zero within the experimental uncertainties. The \(\pi^{+}\) and \(\pi^{-}\) asymmetries measured for the \(^3\)He target and extracted for neutrons are opposite in sign with a small increase observed as a function of \(p_T\).
We present an updated extraction of the proton electromagnetic form factor
ratio, mu_p G_E/G_M, at low Q^2. The form factors are sensitive to the spatial
distribution of the proton, and precise ...measurements can be used to constrain
models of the proton. An improved selection of the elastic events and reduced
background contributions yielded a small systematic reduction in the ratio mu_p
G_E/G_M compared to the original analysis.
High precision measurements of induced and transferred recoil proton polarization in d(polarized gamma, polarized p})n have been performed for photon energies of 277--357 MeV and theta_cm = 20 ...degrees -- 120 degrees. The measurements were motivated by a longstanding discrepancy between meson-baryon model calculations and data at higher energies. At the low energies of this experiment, theory continues to fail to reproduce the data, indicating that either something is missing in the calculations and/or there is a problem with the accuracy of the nucleon-nucleon potential being used.
We have measured the nuclear transparency of the fundamental process gamman-->pi(-)p in He-4. These measurements were performed at Jefferson Lab in the photon energy range of 1.6-4.5 GeV and at ...theta(cm)(pi)=70degrees and 90degrees. These measurements are the first of their kind in the study of nuclear transparency in photoreactions. They also provide a benchmark test of Glauber calculations based on traditional models of nuclear physics. The transparency results suggest deviations from the traditional nuclear physics picture. The momentum transfer dependence of the measured nuclear transparency is consistent with Glauber calculations that include the quantum chromodynamics phenomenon of color transparency.
PDF
