D. Barlow

Identification and measurement of the mass of 26Ne(g.s.) by the 26Mg(π-, π+)26Ne reaction

Abstract The pion double charge exchange reaction 26 Mg(π − , π + ) 26 Ne has been used to make the first observation of 26 Ne(g.s.) and to measure its mass. The reaction 12 C(π − , π + ) 12 B, with known Q 0 = -26.100(15)MeV was used for calibration to obtain 26 Ne(g.s.) mass excess of 0.44(7) MeV.

Polarized proton inelastic scattering from 40Ca and 48Ca at 500 MeV

Abstract Differential cross sections and analyzing powers for inelastic scattering of 500 MeV polarized protons to several low-lying states in 40 Ca and 48 Ca are presented. Phenomenological optical potentials (including density squared terms) have been determined and the data have been analyzed to obtain mass deformation parameters. It is expected that these data will be useful in further testing the recently developed relativistic impulse approximation formalisms and in studying the need for medium modification of the interaction.

Mass of proton-rich 58Zn by pion double charge exchange

Abstract The Tz=−1 nucleus, 58Zn has been identified and its mass measured for the first time. The pion double charge exchange reaction 58 Ni (π + , π − ) 58 Zn was used to produce 58Zn and the mass scale was calibrated by means of the reaction 9 Be (π + , π − ) 9 C , which has very nearly the same Q-value. The atomic mass excess was found to be −42.295±0.050 MeV.

Analyzing power for the p + p → d + π+ reaction at 0.8 GeV and effects of dibaryon admixtures

Abstract A precision measurement of the angular distribution of the analyzing power of the reaction p + p → d + π + has been made at 0.8 GeV. It is shown that none of the existing theoretical calculations, including those which introduce resonant dibaryon amplitudes, reproduce even the qualitative features of the data. It is concluded that our data do not require dibaryon admixtures of the kind proposed for the interpretation of recent data on vector analyzing power, i T 11 (θ), of π− d elastic scattering at the same center of mass energy.

Correlation effects in pion double charge exchange in the f72 shell

Abstract Analog and non-analog transitions have been measured in the reactions 48 Ca(π + , π − ) 48 Ti and 48 Ti(π + , π − ) 48 Cr at pion energies of 130, 180, 235, and 292 MeV, and θ =5°. The ratios of cross sections for the different transitions are discussed in terms of different models of DCX which offer contrasting explanations.

Observation of double analog states in 88Zr and 90Mo and the neutron excess and mass systematics of pion double charge exchange

Abstract The first succesful observation of double analog states in 88 Zr and 90 Mo has been made by means of the ( π + , π − ) pio double charge exchange (DCX) reaction. The systematics of the ( N − Z ) and the A dependence of analog DCX, made possible by these observations, is discussed.

Measurement of the relative sign of neutron and proton transition matrix elements of the 2+ states in 30Si

Abstract Measurement of the inelastic alpha scattering cross sections for the first two 2 + states in 30 Si shows unambigously that the relative sign of the neutron and proton transition matrix elements for both 2 + states are positive. For the first 2 + state, this is consistent with its collective nature. For the second 2 + state, the result is consistent with recent lifetime measurements for the corresponding transition in 30 P but is in contradiction with the prediction of shell-model calculations.

Measurements of Spin-Correlation Parameters all and Asl for P-]P-]-]Pid between 500 and 800 Mev

Measurements of A/sub L/L between 500 and 800 MeV and spin dependent cross sections derived from these measurements are presented for the reaction pp..--> pi..d at c.m. angles theta/sub ..pi../( of 50/sup 0/, 70/sup 0/, and 90/sup 0/. Angular distributions for A/sub S/L are also presented for energies 500, 650, and 800 MeV. These are the first measurements of spin-correlation parameters in this channel above 590 MeV, and are in substantial disagreement with theoretical predictions of the triplet amplitudes above 600 MeV.

A precision test of charge independence

Measurements of pion production from the one‐nucleon transfer reactions p+d to tritium + pi−plus p+d to helium−3 + pi−neutral with polarized protons were taken. Asymmetry results are presented fora test determination of charge independence in hadronic interactions.

Measurements of spin-correlation parametersALLandASLforp→p→→πdbetween 500 and 800 MeV

Measurements of A/sub L/L between 500 and 800 MeV and spin dependent cross sections derived from these measurements are presented for the reaction pp..--> pi..d at c.m. angles theta/sub ..pi../( of 50/sup 0/, 70/sup 0/, and 90/sup 0/. Angular distributions for A/sub S/L are also presented for energies 500, 650, and 800 MeV. These are the first measurements of spin-correlation parameters in this channel above 590 MeV, and are in substantial disagreement with theoretical predictions of the triplet amplitudes above 600 MeV.