Systematics of Isospin Mixing in Proton Elastic Scattering from Light Nuclei

Abstract

The effects of isospin mixing observed by isospin-forbidden resonant proton scattering from the stable, self-conjugate, even-even nuclei exhibit a simple dependence on target mass number A. Furthermore, for A =8?z + 4, n integral, the mixing is systematically a factor of 5 larger than for A =8w. The relation between this behavior and the trends of other relevant nuclear properties is discussed, -^^^^ J ; 164.6° J H J J

β -decay spectroscopy of S27

“…We extract the ratio of Γ γ /Γ p = 0.019(3) from the I γ and I p values. Combining our Γ γ /Γ p ratio with the literature Γ p value [81][82][83] yields a Γ γ = 2.1(5) eV. We have determined an ωγ = 1.0(4) eV by taking into account the I p0 /I ptot = 0.17 (5), deduced from the intensities of proton emission from the IAS (See Table III).…”

“…The USDC and USDI shell-model calculations estimate the Γ γ to be 2.98 and 2.45 eV, respectively, in agreement with the Γ γ = 2.1(5) eV derived from our Γ γ /Γ p ratio and the Γ p from Refs. [81][82][83]. The shell model also indicates that Γ p of the IAS depends on the mixing with a predicted nearby 5/2 + , T = 1/2 state that has a Γ p of 50 keV.…”

“…I. 25 Al T = 3/2 IAS at 7902 keV The proton partial width of the lowest T = 3/2 IAS in 25 Al was determined to be Γ p = 155(50) eV [81,82] and 105 (18) eV [83], respectively, in two proton scattering measurements with polarized-proton beams. These two results agree, and a weighted average Γ p is deduced to be 111 (17) eV.…”

Coulomb corrections to Fermi beta decay in nuclei

“…The value of V 1 is smaller than in the splitting of the IVM and it about 50 MeV (see reference [12] and experimental data quoted in this reference). The coupling between the analog and anti-analog successfully explained [6,13] isospin forbidden decays in light nuclei [14,15]. As one goes to heavy nuclei along the stability line the number of excess neutrons increases which leads to reductions in the matrix element (18) and the increase in the energy splitting (19), causing the mixing of T − 1 impurities to diminish.…”

Nuclear Physics with Polarized Beams

“…Since these are generally widely known, I prefer to concentrate here on the sensitivity of polarized beams to interference and thus to reaction mechanisms. Topics worthy of discussion in this context but omitted here fo r reasons of space include the observation of systematic A dependence in the widths of isospin-forbidden resonances (Ikossi et al 1976), and the interpretation of threshold anomalies in (d, p) reactions (Graw & Hategan 1971). Other technical aspects of IAR have been fr uitfully investigated with polarized beams as well.…”