abstract

It is shown that taking into account the transverse momenta of clusters, one obtains for the short range correlations formulae, which are about as simple as those well-known for the \(p_{\rm T} = 0\) case, but agree much better with experiment.

abstract

The quaternion algebra over the field of complex numbers is used for the realization of transformations from the de Sitter groups \(SO(4,1)\) and \(SO(3,2)\) by the two-row matrices. Within this approach a technique of the so-called horospherical shifts is developed, which are of great importance in quantum field theory with the fundamental length. The spinor representations of both the groups are also constructed. But the virtue of the quaternion lies not so much as yet in solving hard questions, as in enabling us to see the meaning of the question and of its solution. J.C. Maxwell

abstract

The complete spin density matrix of \({\mit \Sigma }^+\)(1385) has been determined by means of the statistical tensor method in the quasi two-body reactions \(\pi ^+\)p \(\to K^+\)+(1385), \({\mit \Sigma }^+\)(1385), \(K^-\)p \(\to \pi ^-{\mit \Sigma }^+\)(1385) and in the inclusive reactions \(\pi ^+\)p \(\to {\mit \Sigma }^+\)(l385)\(+X\), \(K^-\)p \(\to {\mit \Sigma }^+\)(1385)\(+X\), all at 16 GeV/\(c\). It has been found that the experimental results are in good agreement with the predictions of the additive quark model (Q.M.) in the case of the inclusive reactions. In the two-body reactions the statistics is too small to make stronger quantitative statements, the results, however, are not inconsistent with Q.M.

abstract

Production of charmed mesons \(D\) and \(D^*\) in e\(^+\)e\(^-\) annihilation is analyzed. Experimental tests are proposed for the extraction of form factor information from the cross section ratios.

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We critically discuss the applicability of the statistical bootstrap model (SBM) to \(\overline {\rm N}\)N annihilation reactions where statistical properties are much pronounced compared to typical inelastic collisions. To this end we mainly consider multiplicity distributions, single particle spectra and the neutral excess. The available data show that for annihilations in flight (\(p_{\rm lab} \gt 2\) GeV/\(c\)) the dynamics inherent in the SBM is not sufficient for a consistent understanding of the experimentally observed behaviour.

abstract

A model of inelastic proton-proton collisions is discussed in which only \(\varrho \)-mesons are produced, subsequently decaying into pions in the usual way.

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A model of the \(\varrho \) Regge trajectory with correct threshold behaviour and square-root asymptotics is developed. All the data available on charge-exchange \(\pi \)N cross-sections and on difference of the \(\pi ^+\)p and \(\pi ^-\)p total cross-sections at \(p_1 \geq 5\) GeV/\(c\) are analyzed to determine the positions of the leading singularities. Light thresholds with mass up to 1–1.5 GeV are shown to play an appreciable role in the \(\varrho \)-trajectory linearization. The conclusion is drawn from the data on cross-sections that the leading thresholds of the \(\varrho \)-trajectory are not too heavy and they are disposed in the region from 2 to 3 GeV.

abstract

We discuss the Geometrical Scaling (GS) real part effects in the pp elastic differential cross-section, in particular around the dip and at large \(|t|\). The forward ratio \(\varrho ={\rm Re}F/{\rm Im}F\) is accurately predicted from the shape of \(d\sigma /dt\) in the dip region. The real part is shown to tend to flatten and to weaken the energy dependence of the large \(|t|\) differential cross-section. Im\(F(s,t)\) and Re\(F(s,t)\) were constructed numerically in the measured \(t\) region from the GS differential equation relating \(d\sigma /dt\) to the amplitude. We claim, based on our constructed amplitude and on forward dispersion calculations, that the dip must disappear at higher energies, of the order \(\sqrt {s} \simeq \) 300 GeV.

abstract

Compound nucleus contribution to the elastic and inelastic scattering of alpha particles on \(^{28}\)Si nuclei is estimated. The analysis is based on the Hauser–Feshbach theory of compound reactions. For two selected alpha particle energies the experimental energy averaged angular distributions are compared with those calculated as an incoherent sum of direct and compound nucleus (for ground and 1.78 MeV states) or pure compound nucleus (for 4.61 MeV state) cross-sections.

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The generalization of the SU(3) Schwinger mass formula to the SU(4) is given.