• Ramesh C Verma

Articles written in Pramana – Journal of Physics

• Parity violating non-leptonic decays of hyperons and of charmed baryons in SU (8)

The parity violating non-leptonic decays of hyperons and of charmed baryons are discussed in the framework of SU (8) symmetry. Several relations in addition to the ones obtained earlier by using SU (4) symmetry and20″-dominance, are obtained. The assumption of20″-dominance at the SU (4) level is no longer required for explaining the non-leptonic decays of 1/2+ baryons.

• Magnetic moments of baryons in higher symmetry schemes including charm

Relations among the magnetic moments of charmed and uncharmed baryons are derived in the framework of SU(4) and SU(8) symmetries. The SU(3) resultμ (Σo)=−μ(Λ) is not present in SU(4), but is obtained in SU(8). Higher order effects are further considered to improve the situation.

• SU (8) mass relations amongJP=1/2+ and 3/2+ baryons

Mass relations among charmed and uncharmed baryons belonging to20 and20′ multiplets of SU(4) are derived in the framework of SU(8) symmetry, Spin singlet mass breaking interaction is found to give unsatisfactory results. Second order effects and spin triplet mass breaking interactions are studied to improve the situation.

• Adjoint representation admixture to weak nonleptonic decays in SU(4) and SU(8)

In order to remove some of the unsatisfactory features of the GIM model, we consider15-admixture in SU(4). ΔC=±ΔS decays remain unaffected. Lee-Sugawara sum-rule is obtained.15-admixture is extended then to63-admixture in SU(8). The most general Hamiltonian (Hw637201232) in SU(8) is found to give Lee-Sugawara relation and Σ++=0 forS-wave decays of uncharmed baryons. Decay amplitude relations for ΔC=−1, ΔS=0 mode are obtained.

• Charm changing weak decays 1/2+ → 3/2+ + 0/γ in SU(4) and SU(8)w

Weak decay modes (1/2+ → 3/2+ + 0/γ) of charmed baryons are studied. Relations among the various decay amplitudes are derived in isospin, SU(3), SU(4) and SU(8)w symmetries. Sextet dominance in SU(3) forbidsB(3) →D(10) +P(3*) decays. 20″ dominance in SU(4) specifies all the decays in terms of Θ decays. Weak decays of Θ*3++ and Θ are also discussed. SU(8)w symmetry predictsα$$(\Omega \bar k) = 0$$, which is consistent with the experimental value.

• Weak nonleptonic decays of 3/2+ isobars in SU(3)

Weak transitions of decuplet isobars are expanded in terms of eigen-amplitudes of the direct channel in the framework of SU(3). Starting with the most general weak Hamiltonian and assuming intermediate states to be non-exotic, we obtain ΔI=1/2 rule for Ω decays. Invoking of the CP invariance forbids all thepv weak processesD(10)→D(10) +P(8). Decays of the charmed multiplets are also discussed in these dynamical considerations. We obtain triplet dominance of charm changing weak Hamiltonian for Ω*++3 decays.

• Magnetic moments of baryons in broken SU(4)

Assuming that the anomalous magnetic moment interaction has the formaT11 +bT22 +cT44 +sTαα in SU(4), which may arise due to symmetry breaking or some other dynamical effects, we have obtained the magnetic moments and the transition moments of the ordinary and charmed baryons.

• Pramana – Journal of Physics

Volume 94, 2020
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