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Two-proton (2p) radioactivity provides fundamental knowledge on the three-body decay mechanism and the residual nuclear interaction. In this work, we propose decay width formulae in the extended R-matrix framework for different decay mechanisms, including sequential 2p decay, diproton decay, tri-body decay, and sequential two-diproton decay. The diproton and tri-body formulae, combined with information on the two-nucleon transfer amplitude and Wigner single-particle reduced width, can reproduce well experimental 2p radioactivity half-lives. For the case of 67Kr, theoretical predictions for direct 2p decay give much larger half-lives than the recent measurement from RIKEN. A combination of direct and sequential 2p emission is analyzed by considering a small negative one-proton separation energy and a possible enhanced contribution from the p-wave component. The present method predicts that 71Sr and 74Zr may be the most promising candidates for future study on 2p radioactivity. Our model gives an upper limit of 55(4) keV for the decay width of 4p emission in recently found four-proton resonant nuclide, 18Mg, which agrees with the observed width of 115(100) keV.

In this paper, we investigate the charged Higgs boson decay in the context of the type-II two-Higgs-doublet model in the presence of a circularly polarized electromagnetic field of laser radiation. The calculations are performed by adopting the Furry picture approach of non-perturbative interactions with the external electromagnetic field. Using the method of exact solutions for charged particles states in the presence of a circularly polarized electromagnetic wave field and evaluating the S-matrix elements, an exact analytic expression is derived for the decay width of leptonic, hadronic and bosonic decay modes. The branching ratios of different decay modes with multiple photon emission and absorption from the laser beam are analyzed and found to be dramatically modified in the region of superstrong fields. The dependencies of the decay width on the laser field strength and frequency are also examined. The results obtained may be interesting for future experimental and theoretical investigations.

We perform the flavour S U (3) analysis of the recently discovered Ω (2012) hyperon. We find that well known (four star) Δ (1700) resonance with quantum numbers of J P = 3 / 2 − is a good candidate for the decuplet partner of Ω (2012) if the branching for the three-body decays of the latter is not too large ≤70%. That implies that the quantum numbers of Ω (2012) are I (J P) = 0 (3 / 2 −). The predictions for the properties of still missing Σ and Ξ decuplet members are made. We also discuss the implications of the K ‾ Ξ (1530) molecular picture of Ω (2012). In the molecular picture, Ω (2012) state can have quantum numbers of either I (J P) = 0 (3 / 2 −) or I (J P) = 1 (3 / 2 −). Crucial experimental tests to distinguish various pictures of Ω (2012) are suggested. [ABSTRACT FROM AUTHOR]

Abstract: 4He (i.e., α particle) and 6He emissions from possible molecular states in beryllium and carbon isotopes have been investigated using a mean-field-type cluster potential. Calculations can reasonably describe the α-decay widths of studied states in beryllium and carbon isotopes, and also 20Ne, compared with experiments. For the nucleus 10Be, we discussed α-decay widths with different shapes or different decay modes, in order to understand the very different decay widths of two excited states. The widths of 6He decays from 12Be and α decays from 13,14C are predicted, which could be useful for future experiments. [Copyright &y& Elsevier]