- th / 9 70 20 06 v 1 2 F eb 1 99 7 Combined analysis of the reactions pp → pp , πd → πd , and πd → pp

Precision measurements of the pp → π + pn and pp → π + d reactions : importance of long - range and tensor force effects

Inclusive measurements of pion production in proton–proton collisions in the forward direction were undertaken at 400 and 600 MeV at COSY using the Big Karl spectrograph. The high resolution in the π momentum ensured that there was an unambiguous separation of the pp → πd/πpn channels. Using these and earlier data, the ratio of the production cross sections could be followed through the ∆ regio...

Computing Simplicial Representatives of Homotopy Group Elements

A central problem of algebraic topology is to understand the homotopy groups πd(X) of a topological space X. For the computational version of the problem, it is well known that there is no algorithm to decide whether the fundamental group π1(X) of a given finite simplicial complex X is trivial. On the other hand, there are several algorithms that, given a finite simplicial complex X that is sim...

Unitarity constraint for threshold coherent pion photoproduction on the deuteron and chiral perturbation theory

The contribution of the two-step process γd → pn → π0d to the imaginary part of the amplitude for coherent pion production on the deuteron is calculated exploiting unitarity constraints. The result shows that this absorptive process is not negligible and has to be considered in an extraction of the elementary neutron production amplitude from the γd → π0d cross section at threshold. In addition...

ar X iv : n uc l - th / 9 31 10 21 v 1 2 3 N ov 1 99 3 Rates for the reactions pp → πφ and γφ

We study pp annihilation at rest into πφ and γφ. and ρ + ρ − for pp → πφ states is sizable, of order (0.90 to 2.6) × 10 −4 in the branching ratio, but smaller than experiment. For pp → γφ the rescattering contributions are negligible, but the γφ channel is well explained by a ρφ intermediate state combined with vector meson dominance.

- th / 9 71 10 28 v 2 3 1 D ec 1 99 7 A clue to the mechanism of Λ K + production in pp - reactions ∗