U. Gensch

Inclusive single-particle distributions in π±p reactions at 8 and 16 GeV/c

Abstract Invariant single-particle cross sections for pion and proton production in π ± p interactions at 8 and 16 GeV/ c are presented in terms of integrated distributions as functions of x , reduced rapidity ζ and p ⊥ 2 , and also in terms of double differential cross sections E d 2 σ /(d x d p ⊥ 2 ) and d ζ d p ⊥ 2 ). A comparison of π ± and π − induced reactions is made and the energy dependence is discussed. It is shown that the single-particle structure function cannot be factorized in its dependece on transverse and longitudinal momentum. For the beam-unlike pion, there is an indication for factorizability in terms of rapidity and transverse momentum in a small central region.

A comparison of πππ, Kππ, πKKKK system produced in the reactions meson +p→3 mesons + p

Abstract A comparison is made of the low-mass three-meson systems (πππ), (Kππ), (π K K ) and ( K K K ) diffractively produced in the reaction meson + proton → three mesons + proton. Several striking similarities and a few important differences are observed: (i) the reactions are consistent with the assumption that the three mesons decay entirely into a 0− meson and a 0+, 1− or 2+ resonance; (ii) the three-meson mass spectra have a peak ≈ 250 MeV above the effective threshold Meff of the dominant decay mode and then fall off approximately as (mass)−3;(iii) the average spin 〈J〉 = 0.55 + 1.1 Qeff, where Qeff = M - Meff; (iv) the average orbital angular momentum 〈l〉 increases according to 〈l〉 = 0.75 Qeff; (v) the three-meson states are produced dominantly in unnatural spin-parity states and no evidence for their being resonant is found; (vi) the only natural spin-parity states found are the well-established 2+ resonances A2 and K∗ (1420); they have similar properties to the non-resonant unnatural parity states except for a dip at t = 0 in the dσ/dt distributions; (vii) both the unnatural and natural spin-parity states are produced mostly by an exchange of natural parity; (viii) there is evidence for two types of production mechanism with different polarization properties, one approximately conserving helicity in the t-channel and the other in the s-channel.

Multiplicity cross sections for 100 GeV/c π−p interactions

Abstract Charged particle multiplicity cross sections for 100 GeV/ c π − p inelastic interactions are presented and compared with results at other energies. The results for multiplicities n ⪖ 4 show a consistent trend in their energy dependence. The two-prong cross section curve differs as it tends to flatten off at the higher energies. The zero-prong cross section values decrease steeply as p lab −1.1 . The results for n ⩾ 2 for π − p and pp reactions appear to lie on a “universal” curve if nσ n / σ inel is plotted against 〈 n 〉/ n . This “scaling” rule is equivalent to KNO scaling, but the plot suggested here is more useful in studying low multiplicities. An interpretation in terms of a two-component model and a possible extrapolation to higher energies are proposed.

Forward-backward multiplicities in π+p interactions between 8 and 23 GeV/c

Abstract We study the multiplicity distributions and the correlations of charged particles produced forward and backward in the centre-of-mass system. The correlations are small but significant. This type of analysis shows clearly the presence of the diffractive component of the inelastic cross section, amounting to about 15% of it. It is also apparent that KNO multiplicity scaling is not satisfied.

Diffractive proteon fragmentation in 16, 32, and 110 GeV/cK−p interactions and the diffractive production of heavy quarks\((s\bar s,c\bar c)\)

AbstractThe inclusive proton diffraction dissociation cross sections in 16, 32, and 110 GeV/cK−p interactions are determined from the spike nearx=1 in the inclusive negative particle spectra and are compared to those obtained inK−p interactions using other selection methods at various energies. The same procedure is applied to events containing aV0 in order to obtain the cross section for diffractive

Study of the forward peak in π+p reactions at 8, 16 and 23 GeV/c and comparison with ISR results

s\bar s

Neutral strange particle production in high transverse momentum π− nucleus interactions at ∼40 GeV/c

production. While the total cross section for proton diffraction is found to be approximately constant in the energy range studied here, proton diffraction yielding an