Two meson final states in interactions of 2.7 GeV/c p p

Domingo, V. ; Fisher, G.P. ; Marshall Libby, L. ; et al.
Phys.Lett.B 25 (1967) 486-488, 1967.
Inspire Record 1389628 DOI 10.17182/hepdata.29436

The cross sections for π + π − , K + K − , and K 0 K 0 final states from 2.7 GeV/ c p p interactions are: 28±9 γ b, 3 +6 −3 γb, and < 10 γb respectively. Angular distributions are presented and discussed.

1 data table

Axis error includes +- 0.0/0.0 contribution (?////Due to contamination by other final states).


Measurement of $\bar{p} p$ Annihilation Cross-sections Into Charged Particles in the Momentum Range 374-{MeV}/$c$ - 680-{MeV}/$c$

Sai, F. ; Sakamoto, S. ; Yamamoto, S.S. ;
Nucl.Phys.B 213 (1983) 371-389, 1983.
Inspire Record 11837 DOI 10.17182/hepdata.33967

p p annihilation cross sections into 2-, 4- and 6-prong topologies, and the exclusive annihilation cross sections for the π + π − , K + K − , π + π − π 0 , π + π + π − π − , π + π + π − π − π 0 , π + π + π + π − π − π − , and π + π + π + π − π − π − π 0 channels in the momentum range 374–680 MeV/ c were measured. No prominent structure was observed in the momentum dependence of any of the above cross sections, but a small enhancement in the cross section was observed at 490 MeV/ c corresponding to the S meson mass in the topological, and π + π − π 0 and π + π + π − π − π 0 cross sections. If the extensive of the S meson with a mass and width of 1935.5 and 2.8 MeV/ c 2 is assumed, our measurement gives a total resonant annihilation cross section into charged particles of 10.0±3.0 mb.

8 data tables

FIRST CROSS SECTION IS CHARGED ANNIHILATION CROSS SECTION AND IS THE SUM OF THE 2, 4, AND 6PRONG.

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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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Measurement of the Branching Ratio gamma (anti-p p --> e+ e-) / gamma (anti-p p --> Total) in anti-Proton-Proton Annihilation at Rest

Bassompierre, G. ; Binder, G. ; Dalpiaz, P. ; et al.
Phys.Lett.B 64 (1976) 475-478, 1976.
Inspire Record 109375 DOI 10.17182/hepdata.27616

Analyzing a sample of 220 000 events from an experiment still in progress at the CERN Proton Synchrotron (PS), 60 pairs of electrons with an energy above 700 MeV have been observed. The electrons, produced by annihilation of antiprotons stopped in a liquid-hydrogen target, are detected with optical spark chambers and scintillation counters. Twenty-nine out of these 60 pairs have been found to be collinear; normalizing with respect to the hadronic two-body channels π + π − and K + K − , a braching ratio B ee =Γ( p ̄ p → e + e − )/Γ( p ̄ p → total ) = (3.2 ± 0.9) × 10 −7 has been obtained

1 data table

No description provided.


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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$\bar{p} p$ Annihilation Into $\pi^+ \pi^-$ and $K^+ K^-$ From Atomic $p$ States

The ASTERIX collaboration Doser, M. ; Botlo, M. ; Ahmad, S. ; et al.
Nucl.Phys.A 486 (1988) 493-511, 1988.
Inspire Record 261310 DOI 10.17182/hepdata.37012

We have obtained the branching ratios for p p annihilation at rest into π + π − and K + K − in a pure p p initial angular momentum state L = 1. A gaseous hydrogen target at normal pressure and temperature was used and events associated with transitions of the antiprotonic atom to the 2p level were selected by detecting the Balmer X-ray series. The branching ratios for p p annihilation into π + π − and K + K − from the 2p state are (4.81 ± 0.49) × 10 −3 and (2.87 ± 0.51) × 10 −4 , respect The pion yield is slightly larger than in liquid hydrogen, where L = 0 annihilation dominates, while the kaon yield is suppressed by a factor of four. Using these and previous data, we derive the branching ratios for pp annihilation into all ππ and K K modes from S and P states. A measurement in gaseous hydrogen, without X-ray requirement, yields the branching ratios (4.30 ± 0.14) × 10 −3 and (6.92 ± 0.41) × 10 −4 . With the known branching ratios of (3.33 ± 0.17) × 10 −3 and (1.01 ± 0.05) × 10 −3 in liquid hydrogen, we find that (50.3 ± 6.4)% of all annihilations in gas at NTP occur in the initial angular momentum state L = 1.

2 data tables

Axis error includes +- 0.0/0.0 contribution (?////).

Axis error includes +- 0.0/0.0 contribution (?////).


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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Hard exclusive hadron nucleon scattering and color transparency

Heppelmann, S. ; Wu, J.Y. ; Appel, R. ; et al.
Nucl.Phys.A 527 (1991) 581C-583C, 1991.
Inspire Record 327578 DOI 10.17182/hepdata.36761

We present preliminary results on the measurement of a variety of exclusive hadron interactions at center of mass scattering angles of 90°. Data are also presented which show the relative transparency of nuclei to πp and pp elastic scattering in this kinematic range.

3 data tables

No description provided.

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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 SEARCH FOR THE XI(2.2) IN anti-p p FORMATION

Christenson, J.H. ; Kreiter, G.A. ; Nemethy, P. ; et al.
Berkeley High Energy Phys.1986:706, 1986.
Inspire Record 234624 DOI 10.17182/hepdata.20186

None

1 data table

No description provided.


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

No description provided.

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STRANGE PARTICLE PRODUCTION IN ANTI-P P ANNIHILATIONS AT 8.8-GEV/C

Hill, J.C. ; Ansorge, R.E. ; Carter, J.R. ; et al.
Nucl.Phys.B 227 (1983) 387, 1983.
Inspire Record 196402 DOI 10.17182/hepdata.33929

Results are presented from an experiment at the SLAC 40″ hybrid facility (SHF) using an 8.8 GeV/ c antiproton beam. Using external detectors and an on-line trigger, a sample of events enriched in p p annihilations was obtained. pp interactions taken under the same conditions enabled the annihilations to be identified. Cross sections and distributions for the inclusive production of K s 0 and K ∗± (890), and cross sections for exclusive channels with a pair of strange particles are presented.

3 data tables

No description provided.

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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

No description provided.

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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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