ft VALUE OF O$sup 14$ AND THE UNIVERSALITY OF THE FERMI INTERACTION

Journal Article · Sun Jul 15 00:00:00 EDT 1962 · Physical Review (U.S.) Superseded in part by Phys.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.127.583· OSTI ID:4812435

Bardin, R K; Barnes, C A; Fowler, W A; Seeger, P A

The conserved-vector-current theory of the strangenessconserving weak decays predicts that G/sub V/, the vector coupling constant in nuclear beta decay, should be equal to G/sub mu /, the coupling constant in the muon decay. To make possible a more precise comparison of G/sub V/ and G/sub mu /, the ft value of O/sup 14/ has been remeasured. The end-point energy of the positron decay has been determined by measuring the Q values of the reactions C/sup 12/(He/ sup 3/,n)O/sup 14/ and C/sup 12/(He/sup 3/, p)N/sup 14*/ (2.311-Mev state), using the same techniques and equipment where possible in order to minimize the uncertainty in the difference of the Q values. The results of these measurements are Q/sub n/=-1148.8 plus or minus 0.6 kev and Q/sub p/ = 2468.4 plus or minus 1.0 kev, which yield E/sub max/ ( BETA /sup +/) = 1812.6 plus or minus l.4kev, all energies relative to the Li/sup 7/(p,n)Be/sup 7/ threshold assumed as 1880.7 plus or minus 0.4 kev. The half life of O/sup 14/ has also been remeasured as 71.00 plus or minus 0.13 sec, which implies a partial half life of 71.43 plus or minus 0.15 sec for the transition to the 2.311-Mev state of N/sup 14/. Averaged with the recent half life measurement of Hendrie and Gerhart, a ft value of 3075 plus or minus 10 sec is obtained for the O/sup 14/ decay, after correcting for nuclear form factors, electron screening, and K-capture competition. With the radiative corrections of Kinoshita and Sirlin, the value obtained for G/sub V/ is (1.4025 plus or minus 0.0022) x 10/sup -49/ ergcm/sup 3/, where the quoted error is experimental in origin. This is to be compared with the value computed from recent muon decay measurements, G/sub mu / = (1.4312 plus or minus 0.0011) x 10/sup -49/ erg-cm/sup 3/, which is (2.0 plus or minus 0.2)% larger. As there appear to be several possible theoretical explanations for this small discrepancy, the present results are consistent with the conserved-vector-current hypothesis. (auth)

• Research Organization: California Inst. of Tech., Pasadena
• NSA Number: NSA-16-028151
• OSTI ID: 4812435
• Journal Information: Physical Review (U.S.) Superseded in part by Phys.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: 127; ISSN PHRVA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

BETA DECAY
CARBON 12
COUPLING CONSTANTS
CVC THEORY
DECAY
ENERGY
ERRORS
EXCITATION
FERMI INTERACTION
FIELD THEORY
HALF-LIFE
HELIUM 3
INTERACTIONS
MEASURED VALUES
MUONS
NEUTRONS
NITROGEN 14
NUCLEAR REACTIONS
OXYGEN 14
PHYSICS
POSITRONS
PROTONS
Q-VALUE
VECTORS