Experimental Study of the Reactions pˉpππ+\bar{p} p \to \pi^- \pi^+ and KK+K^- K^+ Between 360-{MeV}/cc and 760-{MeV}/cc

Oct, 1989
72 pages
Published in:
  • Phys.Rev.D 41 (1990) 744
Report number:
  • KEK-PREPRINT-89-140
Experiments:

Citations per year

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Abstract: (APS)
The folded differential cross sections dσdΩ(θ*)+dσdΩ(π−θ*), where θ* is the center-of-mass angle of the negatively charged outgoing particle, have been measured for the reactions p¯p→π−π+ and K−K+ at 15 incident beam momenta between 360 and 760 MeV/c with much better statistics than previous experiments. The total cross sections for these reactions, σπ−π+ and σκ−κ+, have also been obtained by integrating the folded differential cross sections. The folded differential cross sections of both reactions show a similar behavior at all measured beam momenta, characterized by a prominent peak at |cosθ*|=1. The cross section σπ−π+ shows a smooth but rapidly decreasing behavior as the beam momentum increases up to 550 MeV/c, whereas σκ−κ+ shows a smooth and flat momentum dependence. These results are compared with some theoretical calculations based on nonrelativistic quark models. Although the shape of the folded differential cross section of the p¯p→π−π+ reaction is rather well reproduced by these models, that of the p¯p→K−K+ reaction, and, in particular, the prominent peak at |cosθ*|=1 cannot be explained at all. The information from other experiments indicates that this discrepancy is most pronounced at the backward angles. Moreover, the momentum dependence of both σπ−π+ and σκ−κ+ is not satisfactorily reproduced by these models.
  • anti-p p: annihilation
  • annihilation: anti-p p
  • anti-p p: exclusive reaction
  • meson: hadroproduction
  • hadroproduction: meson
  • pi: pair production
  • pair production: pi
  • K: pair production
  • pair production: K
  • differential cross section: angular dependence
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