Energy levels of light nuclei A = 5–10

Energy levels of light nuclei A = 16-17

An evaluation of A = 13–15 was published in Nuclear Physics A152 (1970), p. 1. This version of A = 14 differs from the published version in that we have corrected some errors discovered after the article went to press. Figures and introductory tables have been omitted from this manuscript. Reference key numbers have been changed to the NNDC/TUNL format. (References closed December 31, 1969) The original work of Fay Ajzenberg-Selove was supported by the US Department of Energy [DE-AC02-76-ER02785]. Later modification by the TUNL Data Evaluation group was supported by the US Department of Energy, Office of High Energy and Nuclear Physics, under: Contract No. DEFG05-88-ER40441 (North Carolina State University); Contract No. DEFG05-91-ER40619 (Duke University). Nucl. Phys. A152 (1970) 1 A = 14 Table of

Energy Levels of Light Nuclei A = 14

Charge symmetry, quarks and mesons

Energy levels of light nuclei A = 18–19☆

Transitions to (4/sup -/,T=0) states in /sup 16/0 at 17.79 and 19.80 MeV are found to be strongly asymmetric in ..pi../sup +/vs..pi../sup -/ inelastic scattering; in contrast, the ..pi../sup +/ and ..pi../sup -/ cross sections for the (4/sup -/,T=1) state at 18.99 MeV are equal. Three-state isospin mixing is proposed as an explanation. Off-diagonal charge-dependent mixing matrix elements of -147 +- 25 and -99 +- 17 keV are obtained.

Isospin Mixing of4−Particle-Hole States inO16

Measurements of forward-angle cross sections for double charge exchange on /sup 16/O, /sup 28/Si, and /sup 40/Ca at 164 MeV incident pion energy suggest an A/sup -4/3/ dependence for the cross section. This A dependence is shown to provide evidence for ..delta.. components in the nuclear wave function.

Target mass dependence of isotensor double charge exchange: Evidence for deltas in nuclei

Data are presented for pion double charge exchange on targets of /sup 44/Ca, /sup 56/Fe, /sup 58/Ni, /sup 80/Se, /sup 90/Zr, and /sup 118/Sn. These and earlier data are used to examine the mass dependence of double-isobaric-analog transitions and nonanalog ground-state-to-ground-state transitions in the energy region T/sub ..pi../ = 100 to 300 MeV. The implications of the mass dependence to the interpretations of the underlying reaction mechanisms of double charge exchange are discussed.

Mass dependence of pion double charge exchange

The excitation function for ..pi../sup +/ inelastic scattering to the 0/sup +/, T = 1, 3.563-MeV level of /sup 6/Li has been measured at a constant momentum transfer qapprox. =109 MeV/c for incident pion energies from 100 to 260 MeV. Although the differential cross sections extracted for the natural-parity transitions to the 3/sup +/, T = 0, 2.185-MeV and 2/sup +/, T = 0, 4.25-MeV levels are well reproduced within the framework of the distorted-wave impulse approximation, distorted-wave impulse approximation calculations fail to reproduce the anomalous excitation function observed for the transition to the 3.563-MeV level. The shape of the 3.563-MeV excitation function is similar to that previously observed for ..pi../sup + -/ inelastic scattering to the 1/sup +/, T = 1, 15.11-MeV state of /sup 12/C (C.L. Morris et al., Phys. Lett. 108B, 172 (1982)). The same mechanism may be responsible for the observed excitation functions of both ..delta..S = ..delta..T = 1 transitions. A possible mechanism is the previously proposed direct excitation of ..delta..-particle--nucleon-hole (..delta..-h) components in the wave functions.

Pion inelastic scattering to the low-lying excited states of /sup 6/Li

The /sup 14/Be nucleus has been produced in the reaction /sup 14/C(..pi../sup -/,..pi../sup +/). The cross section for the reaction is roughly that which would be expected from the A/sup -4/3/ mass dependence observed for nonanalog (..pi../sup +/,..pi../sup -/) reactions on self-conjugate nuclei. If it is the ground state that we observe, the mass excess of /sup 14/Be is approx.600 keV smaller (more bound) than expected from systematics.

W. B. Cottingame

Papers

Isospin Mixing of4−Particle-Hole States inO16

Target mass dependence of isotensor double charge exchange: Evidence for deltas in nuclei

Mass dependence of pion double charge exchange

Pion inelastic scattering to the low-lying excited states of /sup 6/Li

/sup 14/Be via pion double charge exchange