abstract

Properties of pp and pn multiplicity distributions are analysed within the momentum range 100–400 GeV/\(c\). The pp and pn distributions at 400 GeV/\(c\) were extracted through an empirical model from the pd interaction data at 400 GeV/\(c\). The different significant parameters are derived and consequences discussed.

abstract

Characteristics of the high-energy component of particles produced in inelastic hadron–hadron collisions at energies of 5–5\(\times \)10\(^3\) GeV are analysed on the basis of the phenomenological approximation of known experimental data and Monte-Carlo modelling of individual acts of collision. Qualitative distinctions from the average characteristics of the particles produced become apparent at kinetic energies \(\tau \geq 0.2 \tau _{\rm MAX}\), where \(\tau _{\rm MAX}= \sqrt {s}/2-M\) is the highest possible energy of these particles. A number of methods for separating the “leading” particles are considered. Most of these particles are nucleons, even in the case of \(\pi \)–N collisions. The “leading” particles are produced mainly at the periphery of the interaction region. At \(\tau \gt 0.5 \tau _{\rm MAX}\) the “leading” particle is the fastest one in every act of interaction.

abstract

A new relativistic two-body wave equation is proposed for one spin-1/2 and one spin-0 or spin-1 particle which, if isolated from each other, are described by the Dirac and the Duffin–Kemmer equation, respectively. For a static mutual interaction this equation splits into two equations: a two-body wave equation for one Dirac and one Klein–Gordon particle (which was introduced by the author previously) and a new two-body wave equation for one Dirac and one Proca particle. The proposed equation may be applied in particular to the quark–diquark system. In Appendix, however, an alternative approach is sketched, where the diquark is described as the point limit of a very close Breit system rather than a Duffin–Kemmer particle.

abstract

The Breit equation for a system of two Dirac particles is represented in the scalar\(\otimes \)vector\(\otimes \)tensor form. Then, in the case of equal masses, the internal motion satisfies a generalized Klein–Gordon equation for spin \(s = 0\) (parafermionium) and generalized Proca equations for spin \(s = 1\) (orthofermionium). If the potential is central, one gets for orthofermionium radial wave functions being analogues of electric and magnetic multipole radial fields (but with \(m \not = 0\) and \(V\not \equiv 0\)).

abstract

The levels of \(^{57}\)Co were excited via \(^{56}\)Fe(\(\rho ,\gamma )\) reaction. The DSA technique was employed to deduce the lifetimes of nuclear states. The lifetimes of the levels at 2744 keV, 3109 keV and, 3178 keV were measured for the first time and found to be 68\(^{+30}_{-18}\) fs and 220\(^{+50}_{-30}\) fs respectively.

abstract

The two-body dissipation mechanism in the heavy-ion reaction is investigated in the framework of the time-dependent Hartree–Fock–Bogolyubov theory with a Skyrme II force and a constant gap monopole pairing interaction. The numerical calculations for the central collision of 160 ions show that the two-body dissipation amounts to as much as 40% of the total dissipation of the kinetic energy of colliding ions. This leads to a significant increase of the limiting energy for nonfusion events in central collisions (\(E_{\rm CM}/A \gt 1.75\) MeV) when short range nucleon–nucleon correlations are included. Consequently, the low-\(L\) fusion window is predicted at much higher energies than expected on a basis of time-dependent Hartree–Fock calculations.

abstract

Three infinite sequences of local conservation laws are found for the Kadomtsev- -Petviashvili and 2+1 dimensional Korteweg–de Vries equations by a new method. These laws are then reobtained by an extension of the Noether theorem and appropriate symmetries are found. The new method should simplify general Lie and Lie–Bäcklund calculations by abolishing the need to include explicit \(x\), \(t\) dependence in the generating functions.