Analyzing powers in low-energy neutron scattering from 12C are calculated in an algebraic momentum-space coupled-channel formalism (MCAS). The results are compared with recently obtained experimental data. The channel-coupling potentials have been defined previously to reproduce the total cross section and sub-threshold bound states of the compound system. Without further adjustment, good agreement with data for the analyzing powers is obtained.
A multi-channel algebraic scattering theory, to find solutions of coupled-channel scattering problems with interactions determined by collective models, has been structured to ensure that the Pauli principle is not violated. Positive (scattering) and negative (sub-threshold) solutions can be found to predict both the compound nucleus sub-threshold spectrum and all resonances due to coupled channel effects that occur on a smooth energy varying background.
We report on a first measurement of tensor analyzing powers in quasi-elastic electron-deuteron scattering at an average three-momentum transfer of 1.7 fm$^{-1}$. Data sensitive to the spin-dependent nucleon density in the deuteron were obtained for missing momenta up to 150 MeV/$c$ with a tensor polarized $^2$H target internal to an electron storage ring. The data are well described by a calculation that includes the effects of final-state interaction, meson-exchange and isobar currents, and leading-order relativistic contributions.
The charge form factor of the neutron has been determined from asymmetries measured in quasi--elastic pol.3He(pol e,en) at a momentum transfer of 0.67(GeV/c)^2. In addition, the target analyzing power, A_y^o, has been measured to study effects of final state interactions and meson exchange currents.
The effects of components in an assumed model interaction potential, as well as of the order to which its deformation is taken, upon resonances in the low-energy cross sections and upon sub-threshold bound states of the compound nucleus (${}^{13}$C) are discussed.
A complete high precision set of deuteron analyzing powers for elastic deuteron-proton ($dp$) scattering at 250 MeV/nucleon (MeV/N) has been measured. The new data are presented together with data from previous measurements at 70, 100, 135 and 200 MeV/N. They are compared with the results of three-nucleon (3N) Faddeev calculations based on modern nucleon-nucleon (NN) potentials alone or combined with two models of three nucleon forces (3NFs): the Tucson-Melbourne 99 (TM99) and Urbana IX. At 250 MeV/N large discrepancies between pure NN models and data, which are not resolved by including 3NFs, were found at c.m. backward angles of $theta_{rm c.m.}gtrsim 120^circ$ for almost all the deuteron analyzing powers. These discrepancies are quite similar to those found for the cross section at the same energy. We found small relativistic effects that cannot resolve the discrepancies with the data indicating that other, short-ranged 3NFs are required to obtain a proper description of the data.
J. P. Svenne
,K. Amos
,S. Karataglidis
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(2005)
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"Low-energy neutron-12C analyzing powers: Results from a multichannel algebraic scattering theory"
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Luciano Canton
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