Two-step contribution to the spin-longitudinal and spin-transverse cross sections of the quasielastic (p,n) reactions

The two-step contribution to the spin-longitudinal and the spin-transverse cross sections of ^{12}C,^{40}Ca(p,n) reactions at 494 MeV and 346 MeV is calculated. We use a plane-wave approximation and evaluate the relative contributions from the one-step and the two-step processes. We found that the ratios of the two-step to the one-step processes are larger in the spin-transverse cross sections than in the spin-longitudinal ones. Combining these results with the distorted-wave impulse approximation (DWIA) results we obtained considerable two-step contributions to the spin-longitudinal and the spin-transverse cross sections. The two-step processes are important in accounting for the underestimation of the DWIA results for the spin-longitudinal and the spin-transverse cross sections.Comment: LaTeX 11 pages, 10 figure

Complete Set of Polarization Transfer Observables for the 12C(p,n)^{12}{\rm C}(p,n) Reaction at 296 MeV and 0∘^{\circ}

A complete set of polarization transfer observables has been measured for the $^{12}{\rm C}(p,n)$ reaction at $T_p=296 {\rm MeV}$ and $\theta_{\rm lab}=0^{\circ}$. The total spin transfer $\Sigma(0^{\circ})$ and the observable $f_1$ deduced from the measured polarization transfer observables indicate that the spin--dipole resonance at $E_x \simeq 7 {\rm MeV}$ has greater $2^-$ strength than $1^-$ strength, which is consistent with recent experimental and theoretical studies. The results also indicate a predominance of the spin-flip and unnatural-parity transition strength in the continuum. The exchange tensor interaction at a large momentum transfer of $Q \simeq 3.6 {\rm fm}^{-1}$ is discussed.Comment: 4 pages, 4 figure

Quadrupole deformation of deuterons and final state interaction in 2H⃗(e,e′p)^2 \vec H (e,e'p) scattering on tensor polarized deuterons at CEBAF energies

The strength of final state interaction (FSI) between struck proton and spectator neutron in $^2\vec{H}(e,e'p)$ scattering depends on the alignment of the deuteron. We study the resulting FSI effects in the tensor analyzing power in detail and find substantial FSI effects starting at still low missing momentum p_m \gsim 0.9 fm^{-1}. At larger p_m \gsim 1.5 fm^{-1}, FSI completely dominates both missing momentum distribution and tensor analyzing power. We find that to a large extent FSI masks the sensitivity of the tensor analyzing power to models of the deuteron wave function. For the transversely polarized deuterons the FSI induced forward-backward asymmetry of the missing momentum distribution is shown to have a node at precisely the same value of $p_m$ as the PWIA missing momentum distribution. The position of this node is not affected by FSI and can be a tool to distinguish experimentally between different models for the deuteron wave function.Comment: 24 pages, figures available from the authors on reques

Deuteron-Proton Elastic Scattering at Intermediate Energies

The deuteron-proton elastic scattering has been studied in the multiple scattering expansion formalism. The essential attention has been given to such relativistic problem as a deuteron wave function in a moving frame and transformation of spin states due to Wigner rotation. Parameterization of the nucleon-nucleon $t$-matrix has been used to take the off-energy shell effects into account. The vector, $A_y,$ and tensor, $A_{yy}$, analyzing powers of the deuteron have been calculated at two deuteron kinetic energies: 395 MeV and 1200 MeV. The obtained results are compared with the experimental data

Sensitivity of nucleon-nucleus scattering to the off-shell behavior of on-shell equivalent NN potentials

The sensitivity of nucleon-nucleus elastic scattering to the off-shell behavior of realistic nucleon-nucleon interactions is investigated when on-shell equivalent nucleon-nucleon potentials are used. The study is based on applications of the full-folding optical model potential for an explicit treatment of the off-shell behavior of the nucleon-nucleon effective interaction. Applications were made at beam energies between 40 and 500 MeV for proton scattering from 40Ca and 208Pb. We use the momentum-dependent Paris potential and its local on-shell equivalent as obtained with the Gelfand-Levitan and Marchenko inversion formalism for the two nucleon Schroedinger equation. Full-folding calculations for nucleon-nucleus scattering show small fluctuations in the corresponding observables. This implies that off-shell features of the NN interaction cannot be unambiguously identified with these processes. Inversion potentials were also constructed directly from NN phase-shift data (SM94) in the 0-1.3 GeV energy range. Their use in proton-nucleus scattering above 200 MeV provide a superior description of the observables relative to those obtained from current realistic NN potentials. Limitations and scope of our findings are presented and discussed.Comment: 17 pages tightened REVTeX, 8 .ps figures, submitted to Phys. Rev.

Tensor Ayy and vector Ay analyzing powers in the H(d,d')X and ^{12}C(d,d')X reactons at initial deuteron momenta of 9 GeV/c in the region of baryonic resonances excitation

The angular dependence of the tensor Ayy and vector Ay analyzing powers in the inelastic scattering of deuterons with a momentum of 9.0 GeV/c on hydrogen and carbon have been measured. The range of measurements corresponds to the baryonic resonance excitation with masses 2.2--2.6 GeV/c^2. The Ayy data being in good agreement with the previous results demonstrate an approximate $t$ scaling up to -1.5 (GeV/c)^2. The large values of A_y show a significant role of the spin-dependent part of the elementary amplitude of the NN->NN* reaction. The results of the experiment are compared with model predictions of the plane-wave impulse approximation.Comment: 7 pages, 7 figures. submitted to Yad.Fi

Distorted wave impulse approximation analysis for spin observables in nucleon quasi-elastic scattering and enhancement of the spin-longitudinal response

We present a formalism of distorted wave impulse approximation (DWIA) for analyzing spin observables in nucleon inelastic and charge exchange reactions leading to the continuum. It utilizes response functions calculated by the continuum random phase approximation (RPA), which include the effective mass, the spreading widths and the \Delta degrees of freedom. The Fermi motion is treated by the optimal factorization, and the non-locality of the nucleon-nucleon t-matrix by an averaged reaction plane approximation. By using the formalism we calculated the spin-longitudinal and the spin-transverse cross sections, ID_q and ID_p, of 12C, 40Ca (\vec{p},\vec{n}) at 494 and 346 MeV. The calculation reasonably reproduced the observed ID_q, which is consistent with the predicted enhancement of the spin-longitudinal response function R_L. However, the observed ID_p is much larger than the calculated one, which was consistent with neither the predicted quenching nor the spin-transverse response function R_T obtained by the (e,e') scattering. The Landau-Migdal parameter g'_N\Delta for the N\Delta transition interaction and the effective mass at the nuclear center m^*(r=0) are treated as adjustable parameters. The present analysis indicates that the smaller g'_{N\Delta}(\approx 0.3) and m^*(0) \approx 0.7 m are preferable. We also investigate the validity of the plane wave impulse approximation (PWIA) with the effective nucleon number approximation for the absorption, by means of which R_L and R_T have conventionally been extracted.Comment: RevTex 3, 29 pages, 2 tables, 8 figure

CEREBROSIDE GALACTOSIDASE: A METHOD FOR DETERMINATION AND A COMPARISON WITH OTHER LYSOSOMAL ENZYMES IN DEVELOPING RAT BRAIN 1

(1) A method is described for assaying brain for cerebroside galactosidase activity. The enzyme was liberated by sonication and addition of sodium taurocholate, then by digestion with pancreatic enzymes. It was further purified by precipitation at pH 3. The enzyme was then incubated with an emulsion of galactose-labelled cerebroside in taurocholate and oleate at pH 4·5, and the liberated galactose was determined by scintillation counting. (2) The content of cerebroside galactosidase in rat brain at various ages has been determined. The enzyme was present before cerebroside appears in noticeable amounts (4 days) and the amount rose considerably during the period of active cerebroside deposition and myelination. The amount then remained at a high concentration even in the adult. (3) Comparison with other lysosomal brain enzymes was made in the age study. Nitrophenyl galactoside hydrolase also increased during myelination but levelled off earlier; its activity paralleled the amount of ganglioside. Nitrophenyl glucoside hydrolase started at a lower level and decreased with age. Sulphatase activity rose during myelination, then decreased somewhat after 15 days. Ceramidase followed a pattern similar to that of nitrophenyl galactoside hydrolase; it is suggested that both of these enzymes reflect ganglioside metabolism. (4) The relative amounts of brain enzymes in different states were determined as a function of age in the case of cerebrosidase, nitrophenyl galactoside hydrolase and sulphatase. The proportion found in the high speed supernatant fraction was low but increased after myelination. The proportion that could be ‘solubilized’ by sonication decreased after myelination but the values differed greatly for the three enzymes. This treatment solubilized one-seventh of the cerebrosidase, half the nitrophenyl galactosidase and three-quarters of the sulphatase.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66425/1/j.1471-4159.1969.tb06849.x.pd

Management of intra-abdominal infections : recommendations by the WSES 2016 consensus conference

This paper reports on the consensus conference on the management of intra-abdominal infections (IAIs) which was held on July 23, 2016, in Dublin, Ireland, as a part of the annual World Society of Emergency Surgery (WSES) meeting. This document covers all aspects of the management of IAIs. The Grading of Recommendations Assessment, Development and Evaluation recommendation is used, and this document represents the executive summary of the consensus conference findings.Peer reviewe