HEPData Search

A search for SU(3) manifestly exotic Q2Q¯ 2 baryonium states in antiproton-deuterium interactions was carried out at the SLAC 40-in. hybrid bubble-chamber facility. The I=(3/2, S=1 channel, X−, produced in conjunction with a forward produced neutral antikaon was studied. Such X− states would decay into an antihyperon and a baryon. The fast forward K¯ 0 was detected in a three-view segmented calorimeter placed downstream of the bubble chamber and used as part of the trigger. Upper limits of 0.50–1.63 μb are reported for the X−→Λ¯nπ−, Σ¯ n−, Λ¯pπ−π−, Σ¯ π−−, Σ¯ π∓±π− exclusive channels based upon ≤13 events per channel.

1 data table

Table 1

95 pct confidence level upper limits.

Anti-proton - Neon Annihilation at Rest and at 607-{MeV}/$c$

Balestra, F. ; Bossolasco, S. ; Bussa, M.P. ; et al.

Nucl.Phys.A 491 (1989) 541-571, 1989.

Inspire Record 263202 DOI 10.17182/hepdata.37004

The analysis is based upon p̄Ne annihilation events at rest and at 607 MeV/c detected with a self-shunted streamer chamber exposed to the LEAR beams. The main measured quantities are the following: charged-prong multiplicity, negative pion multiplicity; momentum, angular and rapidity distributions. General distributions are given as well as distributions as functions of charged prong multiplicity. A correlation is found between high multiplicity and depth of the annihilation point. The data are compared with recent theoretical analyses.

4 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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anti-p He-3 REACTION CROSS-SECTION AT 200-MeV/c

Balestra, F. ; Bossolasco, S. ; Bussa, M.P. ; et al.

Phys.Lett.B 215 (1988) 247-250, 1988.

Inspire Record 264048 DOI 10.17182/hepdata.29876

Inelastic p - 3 He events at 192.8 MeV/ c are detected with a self-shunted streamer chamber. The measured reaction cross section is 392±23.8mb. This result is briefly discussed and compared with other reaction cross sections for low-energy p with light nuclei.

2 data tables

Table 1

Charged prong multiplicity distribution in annihilation events.

Table 2

Measured inelastic cross section.

Evidence of Isospin Effects in Anti-proton - Nucleus Annihilation

Balestra, F. ; Bossolasco, S. ; Bussa, M.P. ; et al.

Nucl.Phys.A 491 (1989) 572-586, 1989.

Inspire Record 264049 DOI 10.17182/hepdata.37013

Antiproton- 3 He annihilation events at rest have been detected using a self-shunted streamer chamber. The ratio of the cross section for annihilation on neutrons and on protons has been measured (0.467 ± 0.035). It is compared with other results from annihilation on free nucleons, deuterium, 3 He and 4 He. The low value of the ratio seems to indicate a strong isospin dependence of the antinucleon-nucleon P-wave amplitude.

6 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Polarization of cumulative protons in the reaction gamma A --> p X.

Avakian, R.O. ; Avetisian, A.E. ; Arestakesian, G.A. ; et al.

Sov.J.Nucl.Phys. 49 (1989) 292-294, 1989.

Inspire Record 284675 DOI 10.17182/hepdata.17336

None

2 data tables

Table 1

No description provided.

Table 2

No description provided.

Anti-proton - Helium Annihilation Around 44-{MeV}/$c$

Balestra, F. ; Bossolasco, S. ; Bussa, M.P. ; et al.

Phys.Lett.B 230 (1989) 36-40, 1989.

Inspire Record 276657 DOI 10.17182/hepdata.49625

The p¯4He annihilation cross section averaged over the interval 40–50 MeV/ c has been measured using a streamer chamber in a magnetic field. The measured value is 1342±250 mb. It agrees with a behaviour like 1/ p of the annihilation cross section. Our result has been obtained at the lowest momentum achieved till now in measurements of antiproton annihilation in flight.

1 data table

Table 1

No description provided.

Studies of Jet Production Rates in $e^+ e^-$ Annihilation at $e$({CM}) = 29-{GeV}

Bethke, S. ; Abrams, G. ; Adolphsen, C.E. ; et al.

Z.Phys.C 43 (1989) 325, 1989.

Inspire Record 277772 DOI 10.17182/hepdata.15472

Production rates of multijet hadronic final states are studied ine+e− annihilation at 29 GeV center of mass energy. QCD shower model calculations with exact first order matrix element weighting at the first gluon vertex are capable of reproducing the observed multijet event rates over a large range of jet pair masses. The method used to reconstruct jets is well suited for directly comparing experimental jet rates with parton rates calculated in perturbative QCD. Evidence for the energy dependene of αs is obtained by comparing the observed production rates of 3-jet events with results of similar studies performed at higher center of mass energies.

2 data tables

Table 1

Observed production rates relative to the total hadronic cross section.

Table 2

Production rates corrected for fragmentation, initial state radiation and detector effects.