Polarisation effects in inclusive reactions

Various possible polarisation measurements are distinguished, and their theoretical significance is discussed. (i) It has previously been noticed that simple Regge pole models forbid polarisation effects for the non-fragmenting particle. We propose an absorptive mechanism which can give rise to polarisation asymmetry in this limit and detail the distinctive predictions of this model. We comment on the implications of duality in the missing mass for these polarisation effects. (ii) There are no dynamical reasons for polarisation effects to be forbidden for the fragmenting particle or its fragment. We propose the use of polarisation effects in this kinematic region as a sensitive test of factorisation. (iii) We suggest a number of experiments, with and without polarised targets.     

Exotic reactions in inclusive experiments

The exoticity condition on the energy dependence of inclusive reactions: a + b → c + X is examined in the framework of the “dual-resonance theory”. It is found that abc̄ being exotic is sufficient to guarantee weak energy dependence of the cross-section to leading order. The additional condition also suggested of ab being exotic, concerns only terms of higher orders usually neglected in dual phenomenology and is, in any case. insufficient to guarantee the absence of Regge dependence to such orders.     

Triple Regge behaviour in inclusive reactions

Prominent features associated with a triple Reggeon formula are found to meet the low momentum transfer domain of the K⁺p(K^o) inclusive reaction.     

Polarization in heavy-ion reactions

A series of experiments is described in which beta-ray asymmetry has been used to determine polarization of heavy-ion reaction products¹²B and the present status of the studies of polarization phenomena in heavy-ion reactions is reviewed. A large amount of angular momentum sustained by the two colliding nuclei gives rise to polarization phenomena of reaction products. Coupling between the degrees of freedom accompanying the intrinsic and the relative motions is investigated from the systematic behaviour of polarization of reaction products disclosed by the experiments.     

Diffraction slope and inclusive reactions

The slope of the inelastic overlap function in the 30–1500 GeV p-p scattering is evaluated in a multi-Regge model for inclusive reactions of pp→π^±X and pX. The slope is found larger than the experimental, particularly at high energies. Cluster production and an increase with energy of the averaged pion multiplicity per cluster are inferred.     

Regge phenomenology of inclusive reactions

This project is devoted to updating the Regge phenomenology of inclusive reaction and correlation, with the help of the low p_T data acquired over the last 5 years or so. The analyses over the fragmentation region are largely based on the Mueller-Regge formalism. For the central cross-section and correlation data, however, the Mueller-Regge formalism is seen to be inadequate; and the analyses are largely based on the multiperipheral cluster model and the Gribov calculus. The effort has been to make the individual sections self-contained, at the cost of some duplication. The important gaps remaining in the data, as also in the theoretical interpretation of the available data, are brought out at the end of the relevant sections.     

Polarization phenomena in hadronic reactions

Predictions are made in the framework of the effective color field (ECF) model for polarization observables in $p + A \to \bar \Lambda X$ , A + A → ΛX and p + Pb → pX reactions. The predictions can be checked in the polarization experiments at IHEP (SPASCHARM), JINR (NICA) and BNL (RHIC). Estimates of quark masses and anamolous chromomagnetic quark moments are given.     

High-energy hadron production and inclusive reactions

Recent data on multiparticle production at high energies are reviewed. The major topics include exclusive analyses, multiplicity distributions, single-particle inclusive spectra, and correlations. An effort is made to explore the physical significance of these results.     

Analyzing power of inclusive nuclear reactions

The analyzing power in the inclusive reaction ${}^{12}\text{C(}\text{p}\text{,}\text{p}\text{′)}\text{X}$ was measured at backward angles for E_p=316 and 516 MeV. The results obtained are very small and generally consistent with zero which suggests an indirect or multistep mechanism for emission of protons in the backward hemisphere.     

Operator approach to semi-hadronic inclusive reactions

It is shown how operator product expansions determine the asymptotic behavior of inclusive functions in scaling variables. Such behavior is thus given in scale invariant theories by dimensional analysis. This provides a handle on the (minimal) dimensions of hadronic sources.     

Limiting fragment distributions of inclusive reactions

Using the hypothesis of limiting fragmentation we relate the longitudinal momentum dependence of inclusive reactions at fixed s to the energy dependence of quasi-two-body inelastic cross-sections. The essential features of the longitudinal distributions are shown to be simple consequences of the familier rise near threshold and subsequent fall off at high energies of a quasi-two-body cross section.     

Energy dependence of inclusive distributions in pion-induced reactions

We present data on the inclusive distributions π⁺p → π^± + anything and π⁻p → π⁻ + anything at momenta from 3.7 to 18.5 GeV/c. Distributions are presented in the laboratory, center-of-mass and projectile systems, and the approach to scaling is discussed.     

ϱ dominance and Regge coupling in inclusive reactions

The ? Regge pole residues are calculated under the assumption of ? dominance of the isovector, even G parity component of inclusive reactions. The calculated residues compare well with total cross section data and allow successful predictions of the charge dependence of pion production in the central region. Serious difficulties are encountered with the assumption of P + f dominance of the isoscalar even G parity component.     

Polarization transfer in deuteron stripping reactions

Polarization phenomena involving the spins of a and b in the A(a, b)B reaction are discussed using a complete set of irreducible tensors carrying definite spin transfer. The linear model independent equations relating the cross section and the polarization observables with these tensors are shown to be particularly appropriate for the study of spin dependent interactions, preferentially associated with particular values of spin transfer. The DWBA theory of polarization transfer in deuteron stripping reactions is thoroughly discussed and among the 17 polarization observables we distinguish those likely to be more sensitive to spin dependent distortion, to have stronger deuteron D-state effects, to exhibit the sign-rule j-dependence and other forms of j-dependence. For certain deuteron polarizations, when the spin transfer is pure $\text{s =}\text{1}\text{2}$, it is shown that deuteron stripping reactions are transparent to vector polarization transfer and the outgoing nucléon polarization independent of scattering angle and deuteron energy. DWBA calculations including contributions from spin transfer $\text{3}\text{2}$ through the deuteron D-state and spin-orbit distortion show that polarization transfer in such deuteron polarizations can be explored as a method of producing fast polarized neutrons with known polarization.     

Quark model for multiparticle and inclusive reactions

The relative multiplicity of different hadrons produced in high-energy collisions is found in the framework of the quark model. Appart from the usual hypothesis about the quark structure of hadrons, two extra assumptions are made. Firstly, produced particles are supposed to be mainly the members of the meson 36-plet and baryon (antibaryon) 56-plet. Secondly, production of strange quarks is assumed to be suppressed relative to non-strange quarks roughly by a factor of three, as taken from experiment. In the small-x region the agreement with experimental data is satisfactory. In the fragmentation region it is necessary to take into account the kinematics of the resonant state's decay. The influence of such decay on the x and p_T² distributions of hadrons is discussed.