abstract

The emission of photons by magnetic Bremsstrahlung of strongly interacting neutron pairs is considered. The emission rate is so high that it causes instabilities in the star’s equilibrium.

abstract

The field equations of some self interacting systems with polynomial interaction Lagrangians possess particular solutions similar to solitary waves of classical field theories. These particular solutions can be interpreted as analogues of the operators \(a^{\dagger }_ke^{+ik \cdot x}\) and \(a_ke^{-ik\cdot x}(k\cdot x = k_0x^0-{\bf k} \cdot {\bf x})\), where \(a_k\) and \(a_k^{\dagger }\) are annihilation and creation operators of free field theories. A solitary wave propagator can be constructed using thc superposition principle of quantum theory rather than the mathematical superposition of solutions of a differential equation. The propagator has poles at integral multiples of the mass of the associated linear theory and has zeros which depend upon the coupling constants.

abstract

In this paper we reexamine the problem of the decay law of unstable quantum systems. We show that purely exponential decay law should be measured in experiments in which it is known that a system stays in its initial state until it disintegrates. Here we call such experiments — first kind experiments. The second kind of experiments consist of those in which a system may undergo quantum transitions to other states before decay. Deviations from the exponential decay can be seen, in principle, in these experiments. Decay laws suitable for both kinds of experiments are explicitly derived. A review of the various approaches to the decay law problem is presented in the Introduction.

abstract

A systematic phase displacement has been observed between (d,p) reaction angular distributions measured and those calculated by the conventional DWBA method. It was found that this disagreement could be eliminated if shell and excitation energy dependent optical parameters were introduced.

abstract

The inertial mass parameter \(B\) for the collective quadrupole oscillations is calculated in the adiabatic approximation. It is assumed that the short range residual forces are of the monopole-plus-quadrupole-pairing type. The dependence of the mass parameter on the strength of the quadrupole-pairing interactions, \(G_2\), is investigated in the pure harmonic oscillator model.

abstract

A simple version of the H–F–B pairing calculation, in which the H–F–B average single particle field is approximated by the phenomenological potential with parameters depending on the energy gap, is discussed. It is shown that the corrections to the standard pairing calculation those obtained are approximately included in the VCP method, proposed by the authors earlier. These corrections are important when the energy gain due to the pairing correlations is calculated. It is also concluded that VCP approximately takes into account the particle number projection effects.

abstract

The spin–isospin symmetry energy of nuclear matter, \(\varepsilon _{\sigma \tau }\) is calculated within the frame of the \(K\) matrix theory, in an approximation in which the \(K\) matrix depends on a single density. Results obtained for \(\varepsilon _{\sigma \tau }\) with the Brueckner–Gammel Thaler and the Reid soft core potential, together with previous results for the isospin and spin symmetry energies, \(\varepsilon _{\tau }\) and \(\varepsilon _{\sigma }\) are presented and discussed. The most reliable result is: \(\varepsilon _{\tau } = 53\) MeV, \(\varepsilon _{\sigma } = 65\) MeV, \(\varepsilon _{\sigma \tau } = 76\) MeV, in a reasonable agreement with that obtained with the “empirical” Landau parameters.

abstract

It is shown that correlations between longitudinal and transverse momentum of partons lead to a modified Drell–Yan–West (DYW) relation. In a particular model where the transverse momentum of the leading parton in the proton is \(\sim 1/(1-x)^{1/4}\) for \(x \to 1\), the modified DYW relation is compatible with both \(\nu W_2 \sim (1-x)^4\) for \(x \to 1\) and \(F(Q)\to Q^{-4}\) for \(Q\to \infty \).