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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Comparison of 20 exclusive reactions at large t

White, C. ; Appel, R. ; Barton, D.S. ; et al.
Phys.Rev.D 49 (1994) 58-78, 1994.
Inspire Record 377535 DOI 10.17182/hepdata.50306

We report a study of 20 exclusive reactions measured at the AGS at 5.9 GeV/c incident momentum, 90° center of mass. This experiment confirms the strong quark flow dependence of two-body hadron-hadron scattering at large angle. At 9.9 GeV/c an upper limit had been set for the ratio of cross sections for (p¯p→p¯p)(pp→pp) at 90° c.m., with the ratio less than 4%. The present experiment was performed at lower energy to gain sensitivity, but was still within the fixed angle scaling region. A ratio R(p¯ppp)≈140 was measured at 5.9 GeV/c, 90° c.m. in comparison to a ratio near 1.7 for small angle scattering. In addition, many other reactions were measured, often for the first time at 90° c.m. in the scaling region, using beams of π±, K±, p, and p¯ on a hydrogen target. There are similar large differences in cross sections for other reactions: R(K−p→π+Σ−K−p→π−Σ+)≈112, for example. The relative magnitudes of the different cross sections are consistent with the dominance of quark interchange in these 90° reactions, and indicate that pure gluon exchange and quark-antiquark annihilation diagrams are much less important. The angular dependence of several elastic cross sections and the energy dependence at a fixed angle of many of the reactions are also presented.

21 data tables

Cross sections at 90 degrees in the centre-of-mass.

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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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>A Measurement of the $\bar{p} p \to \pi^+ \pi^-$ Reaction for 158-{MeV}/$c \le p(\bar{p}) \le$ 275-{MeV}/$c$

Bardin, G. ; Burgun, G. ; Calabrese, R. ; et al.
Phys.Lett.B 192 (1987) 471-474, 1987.
Inspire Record 246571 DOI 10.17182/hepdata.30155

A measurement of the total cross section for the reaction p p → π + π − has been performed for seven values of the incident momentum between 158 and 275 MeV/ c . The values obtained, if compared with previous results at higher momenta, agree with a 1/ß dependence. The differential cross section sssumed over the whole incident momentum range has also been measured and the result of a fit by Legendre polynomials is given.

3 data tables

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4*PI*LEG(L=0,P=4) = 1.07 +- 0.13 mb.


BACKWARD SCATTERING IN pi- p ---> p pi-, anti-p p ---> pi+ pi-, K- p ---> p K- AND anti-p p ---> p anti-p AT 8-GeV/c AND 12-GeV/c

The CERN-Lisbon-Moscow-Neuchatel-College de France-Paris collaboration Armstrong, T.A. ; Baubillier, M. ; Brient, J.C. ; et al.
Nucl.Phys.B 284 (1987) 643, 1987.
Inspire Record 230626 DOI 10.17182/hepdata.33525

Data on the reactions π − p → p π − , p p → π + π − , K − p → pK and p p → p p at 8 and 12 GeV/ c are presented. Our results agree with line reversal symmetry (between π − p → p π − and p p → π + π − ), Regge pole behaviour for non-exotic reactions ( π − p → p π − , p p → π + π − ), and universal behaviour for exotic reactions ( p p → p p , K − p → pK − ) with d σ /d u | u =0 ∼ s −10 excluding the existence of a “glory” mechanism in p p elastic backward scattering in our energy range.

4 data tables

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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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Anti-p p annihilation into pi+ pi- and k+ k- at 5 gev/c

Chabaud, V. ; Eide, A. ; Lehmann, P. ; et al.
Phys.Lett.B 41 (1972) 209-212, 1972.
Inspire Record 75628 DOI 10.17182/hepdata.5626

The differential cross-sections for the annihilation processes p p→π − π + and p p→K − K + have been measured at an incident laboratory momentum at 5 GeV/ c . Strong backward and forward peaks are observed in the π + π − differential cross-sections while the K + K − cross-section is shown to have a peak only for K − going forward. The annihilation cross-sections are compared with the cross-sections for the crossed channel backward processes π ± p→p π ± and K ± p→pK ± .

2 data tables

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Elastic scattering and two-body annihilations at 5 gev/c

Eide, A. ; Lehmann, P. ; Lundby, A. ; et al.
Nucl.Phys.B 60 (1973) 173-220, 1973.
Inspire Record 83926 DOI 10.17182/hepdata.7885

We present results of measurements of K ± p and p p elastic scattering and of the annihilation reactions p p →π + π − and p p → K + K − at an incident laboratory momentum of 5 GeV/ c . Nearly complete angular distributions were obtained. Results are also presented for π -meson proton elastic scattering in the momentum transfer ranges 2 < − t < 8 (GeV/ c ) 2 (for π + ) and 0.16 < − t < 7 (GeV/ c ) 2 (for π − ). All measurements were done in one experimental geometry. The measured differential cross sections range from 10 to 10 −5 mb/(GeV/ c ) 2 .

14 data tables

-U = T + 8.486 GEV**2.

THE DATA FOR -T = 7.31 TO 8.45 GEV**2 WERE NORMALIZED TO OTHER EXPERIMENTS.

-U = T + 8.304 GEV**2.

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