Possible differences between free and bound protons may be observed in the ratio of polarizationtransfer components, P x /P z . We report the measurement of P x /P z , in the 2 H( e, e p)n reaction at low and high missing momenta. Observed increasing deviation of P x /P z from that of a free proton as a function of the virtuality, similar to that observed in 4 He, indicates that the effect in nuclei is due to the virtuality of the knock-out proton and not due to the average nuclear density. The measured differences from calculations assuming free-proton form factors (∼ 10%), may indicate in-medium modifications.
We report the first measurements of the transverse (P x and P y ) and longitudinal (P z ) components of the polarization transfer to a bound proton in the deuteron via the 2 H( e, e' p) reaction, over a wide range of missing momentum. A precise determination of the electron beam polarization reduces the systematic uncertainties on the individual components to a level that enables a detailed comparison to a state-of-the-art calculation of the deuteron using free-proton electromagnetic form factors. We observe very good agreement between the measured and the calculated P x /P z ratios, but deviations of the individual components. Our results cannot be explained by medium modified electromagnetic form factors. They point to an incomplete description of the nuclear reaction mechanism in the calculation.Measurements of the polarization transfer P = (P x , P y , P z ) from a polarized electron to a bound nucleon by the A( e, e' p) reaction and their comparison to those of a free proton were suggested as a powerful tool to observe modifications in the bound proton structure [1]. These require detailed calculations incorporating nuclear effects. However, it still might be conceptually difficult to separate such effects from internal nucleon structure changes.
Recently, the use of He particles in cancer radiotherapy has been reconsidered as they potentially represent a good compromise between protons andC ions. The first step to achieve this goal is the development of a dedicated treatment planning system, for which basic physics information such as the characterization of the beam lateral scattering and fragmentation cross sections are required. In the present work, the attenuation of He primary particles and the build-up of secondary charged fragments at various depths in water and polymethyl methacrylate were investigated experimentally for 120 and 200 MeV u beams delivered by the synchrotron at the Heidelberg Ion-Beam Therapy Center, Heidelberg. Species and isotope identification was accomplished combining energy loss and time-of-flight measurements. Differential yields and energy spectra of all fragments types were recorded between 0° and 20° with respect to the primary beam direction.
In the SMART-AF trial, CF stability with sufficient CF was most predictive of optimal 12-month success. (Thermocool Smarttouch Catheter for the Treatment of Symptomatic Paroxysmal Atrial Fibrillation [SMART-AF]; NCT01385202).
We measured the ratio P x /P z of the transverse to longitudinal components of polarization transferred from electrons to bound protons in 12 C by the 12 C( e, e p) process at the Mainz Microtron (MAMI). We observed consistent deviations from unity of this ratio normalized to the free-proton ratio, (P x /P z )12 C /(P x /P z )1 H , for both s-and p-shell knocked out protons, even though they are embedded in averaged local densities that differ by about a factor of two. The dependence of the double ratio on proton virtuality is similar to the one for knocked out protons from 2 H and 4 He, suggesting a universal behavior. It further implies no dependence on average local nuclear density.
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