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Providing strong magnetic holding fields while at the same time guaranteeing shielding from unwanted external fields is a key requirement for the accumulation, preservation, and transport of nuclear-polarized materials: it is a crucial achievement for its exploitation in fusion test facilities and particle physics. High-temperature bulk superconducting materials represent an innovative and promising solution, as they are easily machinable and can be cooled by a coldhead. This work considers a bulk MgB2 superconducting hollow cylinder, and the successful preliminary studies, performed by measuring trapped fields in the order of 1 T in its center, encouraged us to upgrade the prototype apparatus for deep insight and knowledge. The new system allows working at a lower temperature of 8 K, exchanging cylinders and returning to working conditions in 1 day, and mapping the transverse fields along the radial coordinate (in 11 mm) and along the symmetry axis (in 48 mm). Then, it allows us to find the proper geometry and the production procedure for its use in a fusion test facility. The commissioning of the upgraded system provides results already useful for polarized fusion fuel, for instance, as a holding field for recombined hyper-polarized molecules from the recombination of atomic polarized beams, and it also gives the possibility of investigating the use of MgB2 in polarized nuclear targets. [ABSTRACT FROM AUTHOR]

The unpolarized and polarized Beam Charge Asymmetries (BCAs) of the e → ± p → e ± p γ process off unpolarized hydrogen are discussed. The measurement of BCAs with the CLAS12 spectrometer at the Thomas Jefferson National Accelerator Facility, using polarized positron and electron beams at 10.6 GeV is investigated. This experimental configuration allows to measure azimuthal and t-dependences of the unpolarized and polarized BCAs over a large (x B , Q 2) phase space, providing a direct access to the real part of the Compton Form Factor (CFF) H . Additionally, these measurements confront the Bethe-Heitler dominance hypothesis and eventual effects beyond leading twist. The impact of potential positron beam data on the determination of CFFs is also investigated within a local fitting approach of experimental observables. Positron data are shown to strongly reduce correlations between CFFs and consequently improve significantly the determination of R e [ H ] . [ABSTRACT FROM AUTHOR]

A comprehensive set of azimuthal single-spin and double-spin asymmetries in semi-inclusive leptoproduction of pions, charged kaons, protons, and antiprotons from transversely polarized protons is presented. These asymmetries include the previously published HERMES results on Collins and Sivers asymmetries, the analysis of which has been extended to include protons and antiprotons and also to an extraction in a three-dimensional kinematic binning and enlarged phase space. They are complemented by corresponding results for the remaining four single-spin and four double-spin asymmetries allowed in the one-photon-exchange approximation of the semi-inclusive deep-inelastic scattering process for target-polarization orientation perpendicular to the direction of the incoming lepton beam. Among those results, significant non-vanishing cos (ϕ−ϕS) modulations provide evidence for a sizable worm-gear (II) distribution, g 1 T q x p T 2 . Most of the other modulations are found to be consistent with zero with the notable exception of large sin (ϕS) modulations for charged pions and K+. [ABSTRACT FROM AUTHOR]

Summary: Nuclear astrophysics, the union of nuclear physics and astronomy, went through an impressive expansion during the last twenty years. This could be achieved thanks to milestone improvements in astronomical observations, cross section measurements, powerful computer simulations and much refined stellar models. Italian groups are giving quite important contributions to every domain of nuclear astrophysics, sometimes being the leaders of worldwide unique experiments. In this paper we will discuss the astrophysical scenarios where nuclear astrophysics plays a key role and we will provide detailed descriptions of the present and future of the experiments on nuclear astrophysics which belong to the scientific programme of INFN (the Italian National Institute for Nuclear Physics). [ABSTRACT FROM AUTHOR]

Exclusive $$\rho ^0$$ -meson electroproduction is studied by the HERMES experiment, using the 27.6 GeV longitudinally polarized electron/positron beam of HERA and a transversely polarized hydrogen target, in the kinematic region 1.0 GeV $$^2

Exclusive ρ-meson electroproduction is studied in the HERMES experiment, using a 27.6 GeV longitudinally polarized electron/positron beam and unpolarized hydrogen and deuterium targets in the kinematic region 0.5 GeV< Q<7.0 GeV, 3.0 GeV < W<6.3 GeV, and − t′<0.4 GeV. Real and imaginary parts of the ratios of the natural-parity-exchange helicity amplitudes T ( $\gamma^{*}_{T} \rightarrow\rho_{T}$), T ( $\gamma^{*}_{T} \rightarrow \rho_{L}$), T ( $\gamma^{*}_{L} \rightarrow\rho_{T}$), and T ( $\gamma^{*}_{-T} \rightarrow\rho_{T}$) to T ( $\gamma^{*}_{L}\rightarrow\rho_{L}$) are extracted from the data. For the unnatural-parity-exchange amplitude U, the ratio | U/ T| is obtained. The Q and t′ dependences of these ratios are presented and compared with perturbative QCD predictions. [ABSTRACT FROM AUTHOR]

The R&D activities performed in Ferrara regarding a test bench for low temperature field measurement are presented. The system will be built and tested in Ferrara. [ABSTRACT FROM AUTHOR]

A low-energy spin-physics program is being developed at the COSY storage ring. To support the planned experimental activities, several experimental tools for polarized beams and targets have been developed. The paper presents the physics case and the readiness of the setup for its realization. [ABSTRACT FROM AUTHOR]