Failure of the gross theory of beta decay in neutron deficient nuclei

Journal Article · Thu May 28 00:00:00 EDT 2015 · EPJ Web of Conferences

DOI:https://doi.org/10.1051/epjconf/20159301023· OSTI ID:1210038

Firestone, R. B. ^[1]; Schwengner, R. ^[1]; Zuber, K. ^[1]

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1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

The neutron deficient isotopes ^117-121Xe, ^117-124Cs, and ^122-124Ba were produced by a beam of ²⁸Si from the LBNL SuperHILAC on a target of ^natMo. The isotopes were mass separated and their beta decay schemes were measured with a Total Absorption Spectrometer (TAS). The beta strengths derived from these data decreased dramatically to levels above ≈1 MeV for the even-even decays; 3–4 MeV for even-Z, odd-N decays; 4–5 MeV for the odd-Z, even-N decays; and 7–8 MeV for the odd-Z, odd-N decays. The decreasing strength to higher excitation energies in the daughters contradicts the predictions of the Gross Theory of Beta Decay. The integrated beta strengths are instead found to be consistent with shell model predictions where the single-particle beta strengths are divided amoung many low-lying levels. The experimental beta strengths determined here have been used calculate the half-lives of 143 neutron deficient nuclei with Z=51–64 to a precision of 20% with respect to the measured values.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC02-05CH11231
• OSTI ID: 1210038
• Journal Information: EPJ Web of Conferences, Journal Name: EPJ Web of Conferences Vol. 93; ISSN 2100-014X
• Publisher: EDP Sciences
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS