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Masses and magnetic moments of and resonances are calculated employing the hyperspherical approach. We extend our scheme to obtain the helicity amplitudes and transition magnetic moments of the process. We also compute the radiative decay widths and branching ratios of baryons. A comparison of our results with the predictions obtained in recent theoretical models is also presented. [ABSTRACT FROM AUTHOR]

In this paper, we review the results of studies on the decay channels of the standard Higgs boson: H → f + f̅, H → Z + f + f̅, H → W + f + f̅′, H → γ + γ, H → γ + Z and H → g + g. Here ff̅ or ff̅′are the fundamental fermions pair (leptons, quarks). Within the framework of the Standard Model analytical expressions for the partial widths of the indicated decays were obtained and their dependence on the mass of the Higgs boson was studied. [ABSTRACT FROM AUTHOR]

We express the resonant energies of the delta-shell potential in terms of the Lambert W function, and we calculate their decay widths and decay constants. The ensuing numerical results strengthen the interpretation of such decay widths and constants as a way to quantify the coupling between a resonance and the continuum. We calculate explicitly the decay energy spectrum of the resonances of the delta-shell potential, and we show numerically that the lineshape of such spectrum is not the same as, and can be very different from, the Breit–Wigner (Lorentzian) distribution. We argue that the standard Golden Rule cannot describe the interference of two resonances, and we show how to describe such interference by way of the decay energy spectrum of two resonant states. [ABSTRACT FROM AUTHOR]

Decay half-lives are evaluated in the framework of a Woods-Saxon potential model for various clusters decay. In this model cluster-decay are considered as penetration of the cluster-particle through the potential barrier formed by the nuclear, Coulomb and centrifugal interactions between the cluster - particle and core. The spins and parities of the parent and core nuclei, as well as the quadruple deformations of the core nuclei are taken into account for evaluation of the cluster-decay half-lives. The cluster -decay half-lives for isotopes nuclei 156-162Hf coincide well with the experimental data. [ABSTRACT FROM AUTHOR]

From an inelastic excitation and breakup experiment with a Be beam at 29 MeV/u, a large He+He cluster decay width of 1.1(2) MeV is determined for a state at an excitation energy of 10.3 MeV and with a spin parity of 0+. By using the R-matrix analysis, a cluster spectroscopic factor of 0.53(10) is extracted from the cluster partial width, providing a strong support for the clustering structure in Be. A specially designed zero-degree telescope played an essential role in the present experiment and has been demonstrated to be a promising tool in future studies of the molecular-like resonances near the cluster separation threshold. [ABSTRACT FROM AUTHOR]

Numerical solutions of the equations of quantum field theory describing bound s-states of systems of two particles for single boson exchange potentials depending on the energy of the system have been found. On the basis of these solutions, the transition frequencies of the system from the first excited state to the ground state and the decay widths of the bound state of two particles into two photons have been calculated. The obtained energy spectra and decay widths are compared with the experimentally measured values for positronium. [ABSTRACT FROM AUTHOR]

The slope and curvature of Isgur-Wise function for Bc meson is computed in a QCD potential model in two different approaches of choosing the perturbative term of the Cornell potential. Based on heavy quark effective theory the exclusive semileptonic decay rates of Bc meson into the states are exploited. Spin symmetry breaking effects are ignored up to a particular point and the form factors are connected with Isgur-Wise function for other kinematic point since the recoil momentum of from Bc is small due to its heavy mass. [ABSTRACT FROM AUTHOR]

The mass splitting and the decay width of pentaquark (Θ) at the higher angular momentum states have been investigated in the framework of flux tube model considering the diquark-diquark-antiquark configuration for Θ along with statistical model. A quasi particle model for diquark has been considered. The Regge trajectory of Θ has also been investigated with interesting some observations. [ABSTRACT FROM AUTHOR]

Abstract: Inner-shell ionization of atoms, molecules, and clusters often leads to creation of highly excited ionic states that are embedded into double (or even multiple) ionization continua and decay by electron emission. The most common electronic decay process triggered by core ionization is known as Auger effect. The dynamics of the Auger decay is usually assumed to be exponential, and the process is characterized by a decay rate. The advent of the high-intensity x-ray free-electron lasers and their envisaged applications in molecular imaging have made it necessary to consider Auger-type processes in polyatomic systems under conditions of multiple ionization, both in the core and in the valence shells. Here, we review our recent theoretical work on the theory of electronic decay in multiply charged molecules and clusters. Particular attention is given to the effects of the spectator vacancies on the Auger decay rates, trapping of the Auger electron in a multiply charged system, and collective decay of two vacancies. [Copyright &y& Elsevier]

Most of the decaying systems namely α-decay and proton radio activity have extremely narrow widths and hence are termed as quasi-bound states. There are three methods available for the computation of very narrow widths. First, the analytic S-matrix method which treats resonance as a pole in complex energy plane with its real part representing resonance energy and the imaginary part the half width. Another two methods namely (i) direct (D) method and (ii) distorted wave (DW) method are based on the property of the quasi-bound state wave function which is quite similar to a bound state wave function in the interior region and is matched with an outgoing spherical wave representing decaying behavior. We make a comparative study of these methods by applying them to the α-decay systems whose experimental results of Q-value and decay half-lives are known recently. It is observed that all the three methods give practically the same results for widths calculated at the same Q-value and explain the experimental results of Q-values and half-lives in several α-decaying nuclei quite well with a proper Coulomb nuclear interaction potential for the α+daughter nucleus system. [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]

Abstract: The mass and decay width of the with isospin 0 are calculated in a constituent quark model comprising quarks. A correlated basis is used in a non-relativistic five-particle model, and the is identified with a resonance state described as a solution stable against changes in the basis. With the use of a one-gluon exchange quark–quark interaction, the mass is found to be larger than 2 GeV, in a sequence of spin-parity , , , and only the state has a small width to the decay. By shifting the calculated mass to around 100 MeV above the threshold, the level to be identified with the has spin-parity or , though in the latter case it cannot decay to the channel. In addition it is conjectured that other pentaquark states with different spin-parities exist below the . The structure of the pentaquark states is discussed in terms of the densities and two-particle correlation functions of the quarks and in terms of the wave function decompositions into a baryon–meson model and into a diquark-pair model. [Copyright &y& Elsevier]

Based on a relativistic quark model approach, the transition properties of two positive-parity low-lying nucleon resonances Δ(1232) and Roper N(1440)p11 and of Δ*(1600)P33 resonance are investigated. The coupling constants gπNN, gπNΔ, gπNN* and gπNΔ* are also estimated. Two different ways to remove the center-of-mass motion are discussed. Our results of the relativistic approaches with and without the center-of-mass correction are compared to those of the nonrelativistic constituent quark model and to experimental data. Moreover, the effect of the pion cloud on the calculated observables is studied. Better results for the transition properties of the Δ(1232) resonance are obtained by taking the pion cloud into account explicitly. [Copyright &y& Elsevier]