Search

Double differential cross sections and analyzing powers over the quasielastic region have been measured using the ({ital {rvec p}},{ital n}) reaction on {sup 12}C and {sup nat}Pb. The data were obtained at proton energies of 495 and 795 MeV and cover momentum transfers from 1.0--2.1 fm{sup {minus}1} at 495 MeV data and from 0.0--3.5 fm{sup {minus}1} at 795 MeV. The cross section data are compared to results from a nonrelativistic reaction model that includes contributions from two-step scattering. The analyzing power measurements are compared to a recent relativistic plane-waves model.

Complete sets of polarization transfer coefficients have been measured for quasifree ([ital [rvec p]],[ital [rvec n]]) scattering from [sup 2]H, [sup 12]C, and [sup 40]Ca at 494 MeV and scattering angles of 12.5[degree], 18[degree], and 27[degree] ([ital q]=1.2,1.7,2.5 fm[sup [minus]1]). These measurements yield separated transverse ([sigma] [times]/I[ital q]) and longitudinal ([sigma] [center dot]/I[ital q]) isovector spin responses. Comparison of the separated responses to calculations and to electron-scattering responses reveals a strong enhancement in the spin transverse channel. This excess transverse strength masks the effect of pionic correlations in the response ratio.

Differential cross sections and analyzing powers have been measured for inelastic proton excitation of states in $^{12}\mathrm{C}$ up to an excitation energy of 20 MeV. Angular distributions are reported for incoming proton energies of 200, 318, 398, 597, 698, and 800 MeV, typically over the momentum transfer range from 0.5 to 2 ${\mathrm{fm}}^{\mathrm{\ensuremath{-}}1}$; some of these data have been published previously. Reaction calculations in the distorted-wave impulse approximation have been carried out for most of the data. Agreement between theory and experiment for both the magnitudes and shapes of the cross-section data is generally good; the analyzing-power distributions are less well described.

The polarization transfer observable [ital D][sub [ital L][ital L]](0[degree]) has been measured for [sup 2]H([ital [rvec p]],[ital [rvec n]])2[ital p], [sup 12]C([ital [rvec p]],[ital [rvec n]])[sup 12]N, and [sup 14]C([ital [rvec p]],[ital [rvec n]])[sup 14]N reactions with beam energies of 318 and 494 MeV. The deuterium results are in close agreement with free [ital NN] scattering constrained to the [Delta][ital J][sup [pi]]=1[sup +] channel. The results for the carbon targets, however, are systematically more negative than those for deuterium, which suggests a difference between the free and effective nucleon-nucleon interactions. Such a medium modification of the spin-dependent interaction may have important implications for intepretation of other intermediate-energy scattering experiments.

A complete set of polarization-transfer observables has been measured for quasifree (p\ensuremath{\rightarrow},n\ensuremath{\rightarrow}) reactions on $^{2}\mathrm{H}$, $^{12}\mathrm{C}$, and $^{40}\mathrm{Ca}$ at a bombarding energy of 495 MeV and a laboratory scattering angle of 18\ifmmode^\circ\else\textdegree\fi{}. The data span an energy-loss range from 0 to 160 MeV, with a corresponding momentum transfer range of ${\mathit{q}}_{\mathrm{c}.\mathrm{m}.}$=1.7--1.9 ${\mathrm{fm}}^{\mathrm{\ensuremath{-}}1}$. The laboratory observables are used to construct partial cross sections proportional to the nonspin response and three orthogonal spin responses. These results are compared to the transverse spin response measured in deep inelastic electron scattering and to nuclear responses based on the random phase approximation. The polarization observables for all three targets are remarkably similar and reveal no evidence for an enhancement of the spin-longitudinal nuclear response relative to the spin-transverse response. These results suggest the need for substantial modifications to the standard form assumed for the residual particle-hole interaction.

π + and π − production cross sections for 800-MeV protons on C and Cu have been measured at laboratory angles of 0°, 3°, 5°, 7°, 10°, 15°, and 20°. Pions were analyzed using the High Resolution Proton Spectrometer (HRS) facility for momenta from 364 to 675 MeV/ c . Particle identification was made utilizing a time-of-flight method. We estimate the total systematic and statistical error to be ±15% for measurements at 0° and 3° and ±10% at other angles. These data have been used to determine the optimum energy and pion production angle for injection into a proposed superconducting accelerator for pions. Protons are the main source of contamination for a π + beam. Proton-to-pion ratios are given for laboratory angles of 5° and larger.

A complete set of polarization transfer observables for quasifree scattering in the ({rvec p}, {rvec n}) reaction at 495 MeV is reported. Measurements were carried out on CD{sub 2}, natural carbon, and calcium targets at a momentum transfer of 1.72 fm{sup {minus}1} using the new Neutron Time-of-Flight facility at LAMPF. The spin-longitudinal and spin-transverse responses are extracted from the data. The ratio of these responses are compared to DWIA-RPA calculations in which the particle-hole interaction is taken to be of the form g{prime}+{pi}+{rho}. No evidence for these RPA correlations is seen in the data at this momentum transfer. 8 refs., 2 figs.

Complete spin-transfer observables for the two lowest ${1}^{+}$ levels in $^{12}\mathrm{C}$ have been studied with incident protons of 500 MeV. Outgoing protons were detected with an energy resolution of 120 keV at laboratory angles of 3.5\ifmmode^\circ\else\textdegree\fi{}, 5.0\ifmmode^\circ\else\textdegree\fi{}, 7.5\ifmmode^\circ\else\textdegree\fi{}, 9.5\ifmmode^\circ\else\textdegree\fi{}, and 12.5\ifmmode^\circ\else\textdegree\fi{}. Angular distributions of differential cross sections, analyzing powers, and the individual spin observables for each ${1}^{+}$ state are recombined into three transverse and one longitudinal partial differential cross section as well as the spin-sum and spin-difference functions. Results are compared with model calculations and electron-scattering data. Information about experimental quantities not accessible in electron scattering is also discussed.

Analyzing powers (Ay) and spin-rotation-depolarization parameters (DSS, DSL, DLS, DLL, DNN) were determined for 500 MeV p + 2 H and p + 12 C inclusive quasielastic scattering at 10°, 15°, and 20° laboratory scattering angles. The p + 2 H data are consistent with the isospin-average of the proton-proton and proton-neutron scattering observables; the p + 12 C data are not. A relativistic plane wave impulse approximation calculation leads to better agreement with the p + 12 C spin-observables.

Cross sections and analyzing powers have been measured for 12C(p, n) at 494 MeV and 795 MeV and for Pb(p, n) at 795 MeV. The data span an energy loss range of at least 200 MeV, vhich is sufficient to clearly reveal the large peak associated with quasifree neutron knockout. The kinematics, cross section and analyzing power for this peak are compared to the corresponding observables for free nucleon-nucleon scattering and to the observables calculated with a relativistic Fermi-gas model.

Differential cross sections and analyzing powers have been measured for the excitation by 318 MeV protons of states of $^{40}\mathrm{Ca}$ below 7.2 MeV. The data for those normal-parity excitations for which transition densities are available from electroexcitation measurements are analyzed in terms of medium modifications to the nucleon-nucleon interaction. We find that the empirical effective interaction previously fitted to $^{16}\mathrm{O}$(p,p') data at the same energy predicts $^{40}\mathrm{Ca}$(p,p') very well. Density-dependent modifications of the effective interaction fitted to data for $^{40}\mathrm{Ca}$ or $^{16}\mathrm{O}$, either independently or simultaneously, are virtually identical. The density dependence of the empirical interaction is considerably stronger than that of interactions based upon nonrelativistic nuclear matter theory and persists to lower density. The most significant differences are that the empirical interaction has a stronger repulsive core and that absorption is enhanced at high density, contrary to expectations based upon Pauli blocking. We also find substantial suppression of the spin-orbit interaction at low density and enhancement at high density. Nevertheless, the independence of the effective interaction from the target supports the concept of local nuclear matter density. We also find that optical potentials based upon the empirical effective interaction are very similar to Schr\"odinger-equivalent potentials based upon a relativistic impulse approximation model, suggesting that the empirical density dependence is similar to the equivalent density dependence that arises from elimination of lower components from Dirac wave functions. Finally, the results are compared with global optical potentials from Dirac phenomenology.

Analyzing power {ital A}{sub {ital y}} and spin-transfer observables {ital D}{sub {ital i}{ital j}} have been measured for 500-MeV proton inelastic scattering from {sup 28}Si. Measured values of the {ital D}{sub {ital i}{ital j}} for the 9.70-MeV 5{sup {minus}}, {ital T}=0, the 11.58-MeV 6{sup {minus}}, {ital T}=0, and the 14.35-MeV 6{sup {minus}}, {ital T}=1 states are reported at 17{degree} and 22{degree}; values of {ital A}{sub {ital y}} cover the range from about 10{degree} to 26{degree}. Nonrelativistic (NRIA) and relativistic (RIA) impulse-approximation calculations are compared with the data. The differences between the two types of calculations are generally small. The RIA yields excellent agreement with the {ital D}{sub {ital i}{ital j}} data for the 5{sup {minus}} state, and both RIA and NRIA do well for {ital D}{sub {ital i}{ital j}} data for the 6{sup {minus}}, {ital T}=0 state but poorly for the 6{sup {minus}}, {ital T}=1 state. For the {ital A}{sub {ital y}} data, both types of calculation give fairly good predictions for the 5{sup {minus}} and 6{sup {minus}}, {ital T}=1 states, but not for the 6{sup {minus}}, {ital T}=0 state. Comparison between theory and experiment for the combinations of observables {ital D}{sub {ital K}}, which are sensitive to individual termsmore » in the nucleon-nucleon interaction, indicates a possible need for medium corrections in the {ital T}=1 tensor and spin-orbit forces.« less

Analyzing powers have been measured for elastic and inelastic scattering of 500-MeV protons from $^{28}\mathrm{Si}$. These data for the first ${0}^{+}$, ${2}^{+}$, and ${4}^{+}$ states and the corresponding cross-section data have been analyzed with both Schr\"odinger and Dirac equation phenomenological coupled-channels methods. Good, qualitatively similar, results are achieved with the two methods.

Zero-degree cross sections have been measured for the {sup 11}B({ital p},{ital n}){sup 11}C reaction at bombarding energies of {ital E}{sub {ital p}}=160, 200, 494, 644, and 795 MeV. In addition, spectra have been obtained at laboratory scattering angles of 3{degree} and 5{degree} at 494 MeV, and the transverse spin-flip probability at zero degrees has been measured for {ital E}{sub {ital p}}=160 MeV. These data are used to obtain estimates of the Gamow-Teller transition strength to final states in {sup 11}C up to an excitation energy of {ital E}{sub {ital x}}{approx equal}14 MeV. The uncertainty (1 standard deviation) in the extracted transition strengths is estimated to be in the range (2--8)%. Measured cross sections for the first four excited states in {sup 11}C have been compared to distorted-wave impulse approximation calculations. In this comparison, no evidence is found in the cross-section data for certain effects associated with knock-on exchange and noncentral interactions.

Cross sections at 0{degree} for the pure Fermi (0{sup +}, 2.31, MeV) and Gamow-Teller (1{sup +}, 3.95 MeV) states in the {sup 14}C({ital p},{ital n}){sup 14}N reaction have been measured at {ital E}{sub {ital p}}=494, 644, and 795 MeV using the LAMPF neutron time-of-flight facility with a new 617-m neutron flight path. The measured cross sections per unit transition strength, {cflx {sigma}}, provide a measure of the isovector spin-flip and non-spin-flip central components of the effective nucleon-nucleon interaction. Cross sections and the ratio {ital R}{sup 2}={cflx {sigma}}{sub GT}/{cflx {sigma}}{sub F} are compared to lower-energy measurements and to calculations using a free {ital NN} {ital t} matrix.

Differential-cross-section distributions for the {sup 7}Li({ital p},{ital n}){sup 7}Be(g.s.+0.43-MeV) reaction have been measured for {ital E}{sub {ital p}}=80, 120, 160, 200, 494, 644, and 795 MeV. These distributions have been integrated and normalized to independent values for the total cross section obtained from parametrizations of {sup 7}Li({ital p},{ital n}) activation measurements. Zero-degree cross sections obtained from this normalization are reported.

Differential cross sections and analyzing powers have been measured for the 14C(p↘,n)14N*(IAS) reaction at a proton energy of 495 MeV. The data were obtained at the LAMPF Neutron Time‐of‐Flight Facility (NTOF) using a flight path of 400 meters over an angular distribution of θlab=0° to 10° (q=0.0 to 0.956fm−1). Previous Ay results for targets with mixed Fermi (ΔJπ=0+) and Gamow‐Teller (ΔJπ=1+) transitions are not reproduced with either DWIA or RIA calculations. The 14C target offers the best opportunity to study a pure Fermi transition (2.31 MeV) resolved from the nearest Gamow‐Teller (GT) strength (3.95 MeV). The results compare favorably with DWIA and RIA calculations. Thus the discrepancies for mixed Fermi and GT states most likely arise from either failure to understand nuclear structure effects or the nuclear distortion factors.

Complete sets of polarization transfer observables in the quasifree (p↘,n↘) reactions have been measured for the first time. Experiments were performed using the newly calibrated neutron polarimeter and newly developed Neutron Time‐of‐Flight Facility (NTOF) at LAMPF. Measurements were made at 18° and over a broad excitation energy range. The resulting energy‐loss spectra of the spin‐longitudinal and spin‐transverse response functions are presented and discussed for Ca, C, and 2H at 500 MeV, and for a momentum transfer of 350 MeV/c.

We report new cross-section and analyzing-power data for the excitation by 498-MeV protons of all narrow normal-parity states of {sup 16}O below 12.1-MeV excitation. In addition, spin-rotation measurements for elastic scattering and depolarization measurements for the 1{sub 1}{sup {minus}}, 2{sub 1}{sup +}, and 3{sub 1}{sup {minus}} states of {sup 16}O have been performed. These data are used in conjunction with existing data for {sup 40}Ca to study medium corrections to the effective interaction for nucleon-nucleus scattering at 500 MeV. Systematic differences between the data and nonrelativistic impulse approximation calculations based upon either the free {ital t} matrix or a recent density-dependent effective interaction are interpreted within the framework of the local-density approximation. An empirical effective interaction has been constructed which parametrizes the density dependence of the medium modifications in a simple form amenable to phenomenological analysis of data.

A beam of 2 × 1010 protons/s was focused onto a small area on the high-field iris of a superconducting cavity operating at the resonance frequency. The input, reflected, and stored power were monitored. The cavity remained in steady state during this test. We conclude that such superconducting cavities will remain viable in the high-proton-flux environments proposed in the design of a superconducting accelerator for pions (PILAC).

Values of deformation parameters have been extracted from macroscopic coupled-channels analyses of inelastic proton scattering to the first 2 , 3 , and 4 states of SC over the energy range from 200 to 700 MeV. The apparent deformations are almost unchanged over this energy interval; they agree also with nucleon scattering data at much lower energies and at 800 MeV and 1 GeV.

Using a liquid deuterium target, 800 MeV quasielastic $\stackrel{\ensuremath{\rightarrow}}{p}+n$ and $\stackrel{\ensuremath{\rightarrow}}{p}+p$ analyzing powers were measured over the center-of-momentum angular range 14\ifmmode^\circ\else\textdegree\fi{}-75\ifmmode^\circ\else\textdegree\fi{}. Elastic $\stackrel{\ensuremath{\rightarrow}}{p}+p$ analyzing powers were measured over the center-of-momentum angular range 10\ifmmode^\circ\else\textdegree\fi{}-47\ifmmode^\circ\else\textdegree\fi{} using a liquid hydrogen target, and elastic $p+p$ differential cross sections were obtained over the angular range 6\ifmmode^\circ\else\textdegree\fi{}-90\ifmmode^\circ\else\textdegree\fi{} using CH and C${\mathrm{H}}_{2}$ targets. The quasielastic $\stackrel{\ensuremath{\rightarrow}}{p}+p$ data are in good agreement with existing elastic $\stackrel{\ensuremath{\rightarrow}}{p}+p$ data, suggesting that the effects of final state interactions and Fermi motion averaging are small at this energy for the range of momentum transfer covered by these data. Results of phase shift analyses are reported, and the amplitudes important to microscopic analysis of 800 MeV $\stackrel{\ensuremath{\rightarrow}}{p}$+nucleus elastic differential cross section and analyzing power data are discussed. Use of these amplitudes to generate the microscopic Kerman-McManus-Thaler optical potential for 800 MeV $\stackrel{\ensuremath{\rightarrow}}{p}$+$^{40}\mathrm{Ca}$ elastic scattering does not resolve the problems encountered previously concerning nuclear size information and poor fits to the analyzing power data.NUCLEAR REACTIONS $^{2}\mathrm{H}(\stackrel{\ensuremath{\rightarrow}}{p}, pn)p$, $^{2}\mathrm{H}(\stackrel{\ensuremath{\rightarrow}}{p}, pp)n$, $^{1}\mathrm{H}(\stackrel{\ensuremath{\rightarrow}}{p}, p)$, $^{1}\mathrm{H}(p, p)$; ${E}_{p,\mathrm{inc}}=800$ MeV; measured $p+p$ elastic $\frac{d\ensuremath{\sigma}}{d\ensuremath{\Omega}}$ for $6\ifmmode^\circ\else\textdegree\fi{}\ensuremath{\le}{\ensuremath{\theta}}_{\mathrm{c}.\mathrm{m}.}\ensuremath{\le}90\ifmmode^\circ\else\textdegree\fi{}$; measured $\stackrel{\ensuremath{\rightarrow}}{p}+p$ elastic ${A}_{y}(\ensuremath{\theta})$ for $10\ifmmode^\circ\else\textdegree\fi{}\ensuremath{\le}{\ensuremath{\theta}}_{\mathrm{c}.\mathrm{m}}\ensuremath{\le}47\ifmmode^\circ\else\textdegree\fi{}$; measured $\stackrel{\ensuremath{\rightarrow}}{p}+p$ and $\stackrel{\ensuremath{\rightarrow}}{p}+n$ quasielastic ${A}_{y}(\ensuremath{\theta})$ for $14\ifmmode^\circ\else\textdegree\fi{}\ensuremath{\le}{\ensuremath{\theta}}_{\mathrm{c}.\mathrm{m}.}\ensuremath{\le}75\ifmmode^\circ\else\textdegree\fi{}$; CH, C${\mathrm{H}}_{2}$, liquid hydrogen and liquid deuterium targets; two arm coincidence for quasielastic; phase shift analyses; microscopic (KMT) optical model calculations for 800 MeV $\stackrel{\ensuremath{\rightarrow}}{p}$+$^{40}\mathrm{Ca}$.

Measurements for the elastic and inelastic scattering of 500 MeV protons from 40 Ca and 208 Pb at small momentum transfers are reported. The induced proton polarization P and the spin rotation parameter Q were measured for the elastic scattering. The spin rotation parameters D SS ′ , D SL ′ , D LL ′ , d LS ′ and the induced polarization P were measured for transitions to the 3 − (3.37 MeV) and 5 − (4.48 MeV) states in 40 Ca and the 3 − (2.61 MeV) state in 208 Pb. Comparisons of the data with the theoretical calculations were carried out in the framework of nonrelativistic and relativistic approaches. We extracted the spin-up and spin-down channels for the elastic scattering cross sections and found that predictions of the relativistic and nonrelativistic approaches agree well with the spin-up channel data and differ considerably in the spin-down channel.

A set of proton spin observables has been measured for the inelastic transitions to the ${3}^{\ensuremath{-}}$ (3.73 MeV) and ${5}^{\ensuremath{-}}$ (4.48 MeV) states in the $^{40}\mathrm{Ca}(p, {p}^{\ensuremath{'}})^{40}\mathrm{Ca}$ reaction and for the ${3}^{\ensuremath{-}}$ (2.61 MeV) state in the $^{208}\mathrm{Pb}(p, {p}^{\ensuremath{'}})^{208}\mathrm{Pb}$ reaction at 497 MeV. The interval of laboratory scattering angles was 6 to 20\ifmmode^\circ\else\textdegree\fi{} for $^{40}\mathrm{Ca}$ and 2.5 to 14\ifmmode^\circ\else\textdegree\fi{} for $^{208}\mathrm{Pb}$. Comparison of these observables reveals that they satisfy relations analogous to those valid in the elastic scattering of spin \textonehalf{} and spin 0 objects. The origin of these observed relations is explained.NUCLEAR REACTIONS Relations between spin observables in $^{40}\mathrm{Ca}(p, {p}^{\ensuremath{'}})^{40}\mathrm{Ca}$ and $^{208}\mathrm{Pb}(p, {p}^{\ensuremath{'}})^{208}\mathrm{Pb}$ at 500 MeV.

Proton cross sections for $^{208}\mathrm{Pb}$ have been measured for elastic and inelastic scattering to the ${12}^{+}$, 6.10 MeV, ${12}_{1}^{\mathrm{\ensuremath{-}}}$, 6.43 MeV, ${12}_{2}^{\mathrm{\ensuremath{-}}}$, 7.06 MeV, and ${14}^{\mathrm{\ensuremath{-}}}$, 6.74 MeV states at ${E}_{\mathrm{p}=318}$ MeV. We analyze the inelastic transitions in the distorted wave impulse approximation and use the previously published electron scattering results to constrain the wave functions in the unnatural parity calculations. A ${13}^{\mathrm{\ensuremath{-}}}$ state is discussed as an unresolved ``contaminant'' to the ${12}_{1}^{\mathrm{\ensuremath{-}}}$, 6.43 MeV state. Mixing between the ${12}^{\mathrm{\ensuremath{-}}}$ neutron and proton particle-hole configurations is found to reduce substantially the differences reported previously in observed proton and electron quenching factors. This results in greater quenching for the ${12}_{2}^{\mathrm{\ensuremath{-}}}$, 7.06 MeV state, and less quenching for the ${12}_{1}^{\mathrm{\ensuremath{-}}}$, 6.43 MeV state than was previously reported in (e,e') analyses.

Differential cross sections sigma(theta) and analyzing powers A(theta) for pp elastic scattering have been measured in the Coulomb-nuclear interference region at 800 MeV. The measurements, which extend down to 0.5 deg in the laboratory, have been analyzed to deduce the zero-degree pp scattering amplitudes. The ratio rho of the real to imaginary parts of the spin-independent amplitude was found to be -0.04 +- 0.04; the contribution of the double-spin-flip amplitudes to sigma(0) was found to be 0.16 +- 0.03 times that of the spin-independent amplitude; while the ratios of the imaginary and real parts of the single spin-flip amplitude to sintheta were found to be 0.74 +- 0.04 and -0.03 +- 0.08 fm, respectively. Except for the last, these experimental values agree with the predictions of forward dispersion relations and phase shift analyses.

We have used a polarized proton beam to measure the analyzing power for pd backward elastic scattering at incident kinetic energies of 0.68, 1.03, and 1.53 GeV and for the reaction p + p ..-->.. d + ..pi.. at 1.03 GeV. The data indicate that several mechanisms dominate pd backward elastic scattering over this energy range.

Differential cross sections for the inelastic excitation of /sup 12/C by protons have been measured at 0.8 GeV; the range of the angular distribution corresponds to momentum transfers of 0.7--2.4 fm/sup -1/ (1--3.3 m/sub ..pi../). Data for the 1/sup +/(T = 0), 1/sup +/(T = 1), 2/sup +/(T = 1), and the 2/sup -/(T = 1) states at 12.71, 15.11, 16.11, and 16.58 MeV, respectively, have been obtained. These states, as well as the 2/sup +/(T = 0) state at 4.44 MeV, provide a sensitive test of different parts of the effective N-N interaction at 0.8 GeV. We conclude that the differential cross sections for the /sup 12/C excitations can be adequately described in the distorted-wave impulse approximation using a recently published t-matrix interaction.

Results are presented for π+NN → Np yields in 3,4He relative to πd → pp from (π, p) measurements at energies between 50 and 295 MeV and estimates are given for total cross sections. These yields are nearly proportional to the number of target NN pairs, which is not true for 6Li and heavier nuclei. This is believed to indicate that πNN → Np is sensitive to the NN short-range behavior which is deuteron-like for 3,4He but not always so for NN pairs in other nuclei.

A complete measurement of the polarization transfer observables has been made for the first time in the (p, p') reaction at Intermediate energies. Measurements are reported for the 12 C(p, p1') 12 C reaction to the 1 + , T = 0(12.71 MeV) and l + , T = 1(15.11 MeV) states at 500 MeV at laboratory scattering angles of 3.5°, 5.5°, 7.5°, and 12.0°. Linear combinations of these observables are shown to exhibit a very selective dependence on the isoscalar and isovector spin-dependent components of the nucleon-nucleon interaction. To the extent of the validity of the single collision approximation, these amplitudes are compared directly to the free nucleon-nucleon amplitudes at small momentum transfers ( −1 ).

The elastic scattering of 800 MeV polarized protons, with longitudinal, normal, and sideways orientations, from deuterons polarized normal to the scattering plane has been measured. The four-momentum transfer interval measured in this experiment is from 0.03 to 0.17 (GeV/c)/sup 2/. Spin-correlation and spin-transfer observables have been extracted from the data. This experiment is one of a series designed to determine a number of observables in excess of the minimum number required to reconstruct the 12 subamplitudes of the proton-deuteron elastic scattering amplitude directly from spin observables. A comparison of the data with theoretical calculations employing three different phase-shift solutions for NN amplitudes reveals that sizable ambiguities exist in the values of NN amplitudes at small momentum transfers.

It has been suggested that bags containing more than three interacting quarks may be formed in high-energy collisions; these states would appear as narrow resonances in the inelastic channels. We have measured the inclusive cross section d+/sup 4/He..-->..p+X at E/sub c.m./=6.25 to 7.91 GeV in steps of 50 to 100 MeV to search for an eighteen-quark bag resonance. No evidence for narrow resonances was found and upper limits on the production cross section are presented.

Inelastic scattering of 800-MeV protons from $^{40}\mathrm{Ca}$, $^{116}\mathrm{Sn}$, and $^{208}\mathrm{Pb}$ shows a broad giant resonance at an excitation energy of $\frac{110}{{A}^{\frac{1}{3}}}$ MeV. The angular distributions are consistent only with scalar-isoscalar $l=3$ transfer. The excitation energy and width of this high-energy octupole giant resonance are in reasonable accord with theory. However, its energy-weighted sum-rule strength (\ensuremath{\sim}20%) is only about one half that predicted by randomphase-approximation calculations.

The differential cross section for elastic pp scattering has been measured at 800 MeV, for laboratory angles ranging between 1.2° and 4.3° (lab). The ratio ϱ of the real to imaginary parts of the forward spin-independent scattering amplitude and the combined magnitudes of the forward double spin-flip amplitudes have been extracted from the data and are compared with the results of recent forward dispersion relation calculations and phase shift analyses.

The spin rotation parameter Q has been measured for p-/sup 40/Ca-elastic scattering at 497 MeV for 0.01< or =-t< or =0.15 (GeV/c)/sup 2/ with use of the new High Resolution Spectrometer focal plane polarimeter. In conjunction with analyzing power and differential cross section, this measurement uniquely determines the elastic scattering amplitudes up to an arbitrary phase. A parameter-free analysis within the Glauber diffractive approximation with use of N-N phase-shift solutions is presented.

Spin-dipole strength in40Ca has been studied by inelastic scattering of 500-MeV protons and the dipole response in40Ca is compared with the spin-dipole data from the40Ca(p, n) reaction and nonspin-dipole data from photonuclear studies.

The differential cross section for the reaction /sup 12/C(p,p')/sup 12/C* (15.11 MeV, 1/sup +/, T=1) has been measured at 800 MeV; the range of the angular distribution corresponds to momentum transfers of 0.7--2.4 fm/sup -1/ ((1-3.3)m/sub ..pi../). The cross section decreases almost exponentially at large angles; no maximum is observed in the region where nuclear critical opalescence might be expected.

The energy spectra of deuterons recoiling from a deuterium gas target bombarded by transversely polarized 796-MeV protons have been measured to obtain the differential cross sections, dsigma/dt, and analyzing powers, A/sub y/(t), for p-d elastic scattering over a range of laboratory angles from 4.53/sup 0/ to 13.02/sup 0/, corresponding to a range of four-momentum transfer squared, Vertical BartVertical Bar, from 0.013 to 0.108 GeV/sup 2//c/sup 2/. Employing several sets of nucleon-nucleon, N-N, amplitudes obtained from N-N phase shift analyses, comparisons are made between the experimental data and the predictions of a multiple scattering theory. In this region of four-momentum transfer, A/sub y/ is shown to depend almost entirely on the spin-independent and spin-orbit N-N amplitudes.

The elastic differential cross sections of 7.0-GeV/c /sup 4/He scattered from hydrogen (equivalent T/sub p/ = 1.05 GeV) has been measured over a range 0.17 < or = - t < or = 0.85(GeV/c)/sup 2/. The experiment has very low background (< or = 2%), adequate t resolution (< or = 5%), a good absolute normalization (15%), and a statistical accuracy in the interference region of about 3%. The data show a shallow first minimum and a shape very similar to the recent data from Centres d'Etudes Nucleaires de Saclay.

The absolute cross sections for the production of 11 C by 1.59 GeV and 4.19 GeV α-particles incident on natural carbon have been measured to be 46.4 ± 1.3 mb and 42.5 ± 1.1 mb respectively. These results, together with data reported at other energies, indicate that the C(α, X) 11 C cross section becomes approximately constant at a value of about 43 mb for energies above 3 GeV (750 MeV/n). A similar energy dependence is exhibited by the C(p, X) 11 C reaction whose cross section has been measured previously over an extensive energy range. The C(α, X) 11 C cross sections are found to be in good agreement with predictions of a semi-empirical model developed to describe nuclear fragmentation.

A method is described in which 805 MHz acceleration cavities in the LAMPF linac are used to form a nearly isochronous beam of particles for use in high-resolution neutron time-of-flight spectroscopy at energies less than 800 MeV.

Differential cross section measurements have been made for the giantresonance region (13.2--40 MeV) in /sup 40/Ca using 500 MeVprotons with an experimental energy resolution of 70 keV. Fine structure wasobserved in this energy region. After fixing the energy weighted sum ruledepletion for the isovector giant dipole resonance at 70%, energy weighted sumrules of 70+-14 % for the isoscalar giant quadrupole resonanceand 15+-3 % for the isoscalar giant hexadecapole resonance werededuced. All of these energy weighted sum rule depletions agree well withtheoretical predictions and results from other experiments.

Single particle inclusive spectra and the associated multiplicity were obtained with a magnetic spectrometer and an azimuthal array of 30 Cerenkov counters from collisions of 1.8 GeV/nucleon 40 Ar on Be and Cu targets. No change is seen in the shape of the spectra obtained by the spectrometer for various multiplicity requirements.

We have measured the differential cross section d 2 σ/ d Ω d T for the double charge exchange reactions 4He(π+, π−)4p and 3He(π−, π+)3n at 140, 200 and 295 MeV. By fitting this data with a simple phase-space model we have estimated the integrated cross section d σ/ d Ω and the total cross section. The 4He data agree qualitatively with the predictions of a meson exchange calculation and with one version of the successive single charge exchange model. The 3He cross sections are considerably larger than those of 4He and in some cases the missing mass plot shows a strong enhancement, which resembles a broad three-nucleon resonance.

Differential cross sections are reported for ..pi../sup +/+/sup 3,4/He elastic scattering at 260, 295, and 310 MeV and ..pi../sup -/+/sup 3,4/He at 295 MeV. The angular distributions )except for ..pi../sup -/+/sup 3/He) confirm the fixed angle (thetaapprox. =75/sup 0/) minimum seen at lower energies (caused by the (3,3) ..pi..+N resonance dominance) and show a deep minimum at thetaapprox. =110/sup 0/. Comparisons are made to ..pi..+d and the current discussion of pion excitation of intermediate dibaryon and ..delta..N states.

Measurements for spin observables for elastic scattering of 320, 400, 500, 650, and 800 MeV protons from /sup 16/O and /sup 40/Ca are reported. Comparisons of the data with theoretical calculations were carried out in the framework of nonrelativistic and relativistic approaches. The differences between the relativistic and nonrelativistic predictions are found, in agreement with earlier theoretical predictions, to decrease with the increasing energy. The trend can be best seen by examining the data for the spin-down channel differential cross sections. Unlike the spin-up cross sections, they are sensitive to the relativistic corrections. For all targets and energies considered, predictions of the relativistic and nonrelativistic approaches are similar and agree with the spin-up channel data. The predictions differ considerably in the spin-down channel.

Measurements of the tensor and vector spin observables C(0,NN,0,0), C(0,SS,0,0), and C(0,N,0,0), in p-d elastic scattering at 600, 800, and 1000 MeV equivalent proton bombarding energy, are reported. The data were taken in the range 0.1