32 research outputs found
A study of T = 2 states in ¹²B, ¹²C, ²⁰F and ²⁸Al
The lowest T = 2 states have been identified and studied in
the nuclei 12C, 12B, 20F and and 28Al. The first two of these were
produced in the reactions 14C(p,t)12C and 14C (p,3He)12B, at 50.5 and
63.4 MeV incident proton energy respectively, at the Oak Ridge
National Laboratory. The T = 2 states in 20F and 28Al were observed
in (3He,p) reactions at 12-MeV incident energy, with the Caltech
Tandem accelerator.
The results for the four nuclei studied are summarized below:
(1) 12C: the lowest T = 2 state was located at an excitation
energy of 27595 ± 20 keV, and has a width less than 35 keV.
(2) 12B: the lowest T = 2 state was found at an excitation
energy of 12710 ± 20 keV. The width was determined to be less than
54 keV and the spin and parity were confirmed to be 0+. A second
12B state (or doublet) was observed at an excitation energy of
14860 ± 30 keV with a width (if the group corresponds to a single
state) of 226 ± 30 keV.
(3) 20F: the lowest T = 2 state was observed at an excitation
of 6513 ± 5 keV; the spin and parity were confirmed to be 0+. A second
state, tentatively identified as T = 2 from the level spacing, was
located at 8210 ± 6 keV.
(4) 28Al: the lowest T = 2 state was identified at an excitation
of 5997 ± 6 keV; the spin and parity were confirmed to be 0+. A second
state at an excitation energy of 7491 ± 11 keV is tentatively identified
as T = 2, with a corresponding (tentative) spin and parity assignment
Jπ = 2+.
The results of the present work and the other known masses of
T = 2 states and nuclei for 8 ≤ A ≤ 28 are summarized, and massequation
coefficients have been extracted for these multiplets.
These coefficients were compared with those from T = 1 multiplets,
and then used to predict the mass and stability of each of the unobserved
members of the T = 2 multiplets.</p
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