Search for Structures in the $\bar{p} p \to \pi^+ \pi^-$ and $\bar{p} p \to K^+ K^-$ Cross-sections Between 360-{MeV}/$c$ and 760-{MeV}/$c$

Sugimoto, Y. ; Sudou, M. ; Fujii, T. ; et al.
Phys.Rev.D 37 (1988) 583, 1988.
Inspire Record 252971 DOI 10.17182/hepdata.38415

Cross sections 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 significantly better statistics than previous experiments in this momentum region. No significant structure has been found in either channel. The values of 90%-confidence-level upper limits for the possible resonance cross sections are given.

31 data tables
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Differential cross-sections and analyzing powers for anti-p p ---> pi- pi+ and K- K+ from 360-MeV/c to 1550-MeV/c

Hasan, A. ; Bugg, D.V. ; Hall, J.R. ; et al.
Nucl.Phys.B 378 (1992) 3-51, 1992.
Inspire Record 339576 DOI 10.17182/hepdata.6880

Analysing powers and differential cross sections for p p → π − π + and p p → K − K + have been measured over the full angular range using a polarised target at LEAR at 20 beam momenta from 360 to 1550 MeV/ c . Discrepancies in the normalisation of earlier d σ/ d Ω data at low momenta are clarified. Above 1000 MeV/ c , A 0N results confirm values close to +1 over most of the angular range for both reactions, in excellent agreement with earlier data of lower statistics. Below 1000 MeV/ c , where the analysing power is measured for the first time, large variations of A 0N with energy and angle are present.

84 data tables

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

Tanimori, T. ; Ishimoto, S. ; Nakamura, K. ; et al.
Phys.Rev.D 41 (1990) 744, 1990.
Inspire Record 283782 DOI 10.17182/hepdata.22921

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.

33 data tables

Folded differential cross sections.

Folded differential cross sections.

Folded differential cross sections.

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OBSERVATION OF AN ENHANCEMENT IN ANTI-P P ---> PI+ PI- AND ANTI-P P ---> K+ K- CROSS-SECTIONS AT ANTI-P MOMENTUM OF APPROXIMATELY 500-MEV/C

Tanimori, T. ; Fujii, T. ; Kageyama, T. ; et al.
Phys.Rev.Lett. 55 (1985) 1835-1838, 1985.
Inspire Record 221965 DOI 10.17182/hepdata.20293

The reactions p¯p→π+π− and K+K− have been studied at 390, 490, 590, 690, and 780 MeV/c. An enhancement of about 150 μb has been observed in the cross sections of both reactions at the same beam momentum of 490 MeV/c. If this structure is interpreted as a meson resonance, it has a mass of 1940 ± 20 MeV and a width of less than 40 MeV.

11 data tables

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