ISOTOPIC-SPIN RULE VIOLATION IN THE B$sup 10$(d,/cap alpha/)Be$sup 3$ REACTION

Journal Article · Tue Aug 01 04:00:00 EDT 1961 · Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D

DOI:https://doi.org/10.1103/PhysRev.123.958· OSTI ID:4843927

Erskine, J R; Browne, C P

All previous tests of the isotopic-spin selection rule in (d, alpha ) reactions were obscured by statistical weight factors because in each case the initial and final nuclear states had spin and parity 0/sup +/. The B/sup 10/(d, alpha )Be/sup 8/ reaction provides a test of the isotopic-spin selection rule free from this restriction. The energy levels of Be/sup 8/ near the lowest T = 1 level were studied with the Li/sup 6/(He/sup 3/,p)Be/sup 8/ and Be/sup 9/(He/sup 3/, alpha )Be /sup 8/ reactions as well as with the B/sup 10/(d, alpha )Be/sup 8/ reaction. Energy levels in Be/sup 8/ were found at 16.623 plus or minus 0.010 Mev, 16.921 plus or minus 0.010 Mev, and 17.637 plus or minus 0.006 Mev. The widths are 95 plus or minus 20 kev, 85 plus or minus 20 kev, and <15 kev, respectively. The first of these levels is the lowest T = 1 state, whereas the sec ond is T = 0 and the third probably T = 1. Energy levels at 16.08 Mev and a J = 2 level at 17.7 Mev, reported by other laboratories, were not observed. The ratio of the differential cross sections for formation of the 16.62- and 16.92- Mev levels was measured over a range of angles and bombarding energies. The ratio is about 1.4 and is roughly constant for both the Li/sup 6/(He/sup 3/,p)Be/ sup 8/ and B/sup 10/(d, alpha )Be/sup 8/ re actions. This implies complete violation of the selection rule because the latter reaction should not go to the T = 1 level. Arguments are given which indicate that the T = 0 impurities in the 16.62-Mev T = 1 level are probably quite small. Consequently, the failure of the selection rule probably results from the complete intermixing of T = 0 and T = 1 states in the C/sup 12/ compound nucleus near 28-Mev excitation. Groups from the C/sup 12/(He/sup 3/,p)N/sup 14/ reaction were seen corresponding to levels in N/ sup 14/ at 5.691 plus or minus 0.008, 5.834 plus or minus 0.008, 6.203 plus or minus 0.008, and 6.440 plus or minus 0.008 Mev. (auth)

• Research Organization: Univ. of Notre Dame, Ind.
• NSA Number: NSA-15-026972
• OSTI ID: 4843927
• Journal Information: Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D, Journal Name: Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D Vol. Vol: 123; ISSN PHRVA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ALPHA PARTICLES
ANGULAR DISTRIBUTION
ANGULAR MOMENTUM
BERYLLIUM 8
BERYLLIUM 9
BORON 10
CARBON 12
COMPOUND NUCLEI
CROSS SECTIONS
DEUTERON BEAMS
ENERGY
ENERGY LEVELS
EXCITATION
HELIUM 3
ION BEAMS
ISOSPIN
LITHIUM 6
MEASURED VALUES
MEV RANGE
MOMENTUM
NITROGEN 14
NUCLEAR MODELS
NUCLEAR REACTIONS
PARITY
PHYSICS
PROTONS
QUANTUM MECHANICS
SELECTION RULES
SPIN
TRANSIENTS