Al-Bataineh, H.
PBAR P --> X
Integrated Cross Section
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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
Table 1

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

Table 2

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


Real to Imaginary Ratio of the $\bar{p} p$ Forward Elastic Scattering Amplitude in the Momentum Range Between 180-{MeV}/$c$ and 590-{MeV}/$c$

Bruckner, W. ; Dobbeling, H. ; Guttner, F. ; et al.
Phys.Lett.B 158 (1985) 180-185, 1985.
Inspire Record 213992 DOI 10.17182/hepdata.30392

The real-to-imaginary ratio of the p p forward elastic scattering amplitude has been measured at the LEAR facility of CERN by the Coulomb-nuclear interference method at seven beam momenta between 181 and 590 MeV/ c . The ratio is positive at 590 MeV/ c , becomes negative below 500 MeV/ c , reaches a minimum at 260 MeV/ c and then crosses zero again at about 230 MeV/ c .

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.


SEARCH FOR NARROW STRUCTURES IN ANTI-P P TOTAL CROSS-SECTION FROM 395-MEV/C TO 740-MEV/C

Nakamura, K. ; Aihara, H. ; Chiba, J. ; et al.
Phys.Rev.D 29 (1984) 349-362, 1984.
Inspire Record 202201 DOI 10.17182/hepdata.23686

We report the final results of a search for narrow structures in the p¯p total cross section between 395 and 740 MeV/c with a rms mass resolution of 1.5 MeV around the S-resonance region. A reanalysis of the data significantly improved the statistical accuracy. No evidence is found for narrow structures and a 90%-confidence-level upper limit of 24 mb MeV is set at around 500 MeV/c for the integrated cross section of a Breit-Wigner-type resonance of width ≲4 MeV.

1 data table
Table 1

No description provided.


SEARCH FOR THE S MESON

Hamilton, R.P. ; Pun, T.P. ; Tripp, R.D. ; et al.
Phys.Rev.Lett. 44 (1980) 1182-1185, 1980.
Inspire Record 157724 DOI 10.17182/hepdata.20738

Total and annihilation cross sections for p¯p and p¯d have been measured over the momentum range 355-1066 MeV/c at closely spaced momenta and with good energy resolution. No evidence is seen for the narrow structure reported by other experiments in the vicinity of 500 MeV/c. The present measurements indicate a broader enhancement in this region, which, if interpreted as a resonance, would have a height of ∼ 3 mb and a width of ∼ 20 MeV. This structure appears only in the p¯p data.

2 data tables
Table 1

No description provided.

Table 2

No description provided.


EVIDENCE AGAINST THE NARROW S (1936) IN A MEASUREMENT OF ANTI-P P TOTAL CROSS-SECTION

Kamae, T. ; Aihara, H. ; Chiba, J. ; et al.
Phys.Rev.Lett. 44 (1980) 1439-1442, 1980.
Inspire Record 157934 DOI 10.17182/hepdata.20724

The total p¯p cross section has been measured in the S region by the transmission method with use of a beam-monitoring spectrometer. The result is inconsistent with the existence of the narrow resonance S(1936) with cross sections reported by previous experiments.

1 data table
Table 1

No description provided.


The Real Part of anti-p p Forward Elastic Scattering Amplitude at 0.7-GeV/c

Kaseno, H. ; Hamatsu, R. ; Kawano, K. ; et al.
Phys.Lett.B 61 (1976) 203-206, 1976.
Inspire Record 3400 DOI 10.17182/hepdata.27693

The differential cross sections of p p elastic scattering at 0.7 GeV/ c were obtained in the range 0.0018<| t |⩽0.0320 GeV 2 . From the interference between the Coulomb and the nuclear amplitude, the ratio of real to imaginary part of the forward nuclear amplitude was found to be +0.33±0.04.

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

FIT FOR FORWARD NUCLEAR AMPLITUDE IN COULOMB INTERFERENCE REGION.


Measurement of the Total and Partial anti-p p Cross-Section Between 1901-MeV and 1950-MeV

The CERN-Liverpool-Mons-Padua-Rome-Trieste collaboration Chaloupka, V. ; Drevermann, H. ; Marzano, F. ; et al.
Phys.Lett.B 61 (1976) 487-492, 1976.
Inspire Record 108895 DOI 10.17182/hepdata.27669

The presence of a structure in the p̄p total cross section at 1930–1940 MeV, with a narrow width of 9 MeV is confirmed. The interpretation of the effect as a single, non interfering, resonance is made difficult by the comparison of the elastic scattering with the charge exchange cross sections.

1 data table
Table 1

'INELASTIC' IS 0+2+4+6 PRONGS MINUS ELASTIC.


Anti-p p elastic and charge exchange scattering at 230 mev

Kohno, H. ; Kaneko, S. ; Murata, Y. ; et al.
Nucl.Phys.B 41 (1972) 485-492, 1972.
Inspire Record 75157 DOI 10.17182/hepdata.6879

Reactions p p → p p and p p → n n were studied at the kinetic energy 230 MeV of incident p by using bubble chamber films. Total cross sections for both of the reactions were found to be 51.2 ± 1.6 mb and 9.1 ± 0.6 mb, respectively. Differential cross sections are well explained by the phenomenological theory given by Bryan and Phillips.

5 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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