HEPData Search

Showing 10 of 44 results

$\bar{p} p$ 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 (?////).

A Luminosity Independent Measurement of the $\bar{p} p$ Total Cross-section at $\sqrt{s}=1$.8-tev

The E-710 collaboration Amos, Norman A. ; Avila, C. ; Baker, W.F. ; et al.

Phys.Lett.B 243 (1990) 158-164, 1990.

Inspire Record 27474 DOI 10.17182/hepdata.29696

We report a measurement of the p p total cross section at √ s =1.8 TeV using a luminosity-independent method. Our result is σ T =72.1±3.3 mb ; we also derive the total elastic cross section σ el =16.6±1.6 mb. A value is obtained for the total single diffraction cross section of 11.7±2.3 mb.

4 data tables

Table 1

No description provided.

Table 2

Assuming RHO = 0.145.

Table 3

No description provided.

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A MEASUREMENT OF THE ANTI-P P DIFFERENTIAL ELASTIC CROSS-SECTION AND OF THE COULOMB - NUCLEAR INTERFERENCE BETWEEN 353-MEV/C AND 578-MEV/C

Cresti, M. ; Peruzzo, L. ; Sartori, G. ;

Phys.Lett.B 132 (1983) 209-213, 1983.

Inspire Record 200209 DOI 10.17182/hepdata.30632

We have measured the p p differential elastic cross section at 8 momenta from 353 to 578 MeV/ c , determining, for each momentum, the ratio ρ of the real to imaginary parts of the elastic forward amplitude, the slope b of the elastic cross section and the total p p cross section σ. Our results are compared with previous experimental results and with theoretical predictions.

3 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

Numerical values supplied by M. Cresti.

Analysis of the Highest Transverse Energy Events Seen in the UA1 Detector at the S $p \bar{p}$ S Collider

The UA1 collaboration Albajar, C. ; Albrow, M.G. ; Allkofer, O.C. ; et al.

Z.Phys.C 36 (1987) 33, 1987.

Inspire Record 248074 DOI 10.17182/hepdata.15751

This is the first full solid angle analysis of large transverse energy events in$p\bar p$ collisions at the CERN collider. Events with transverse energies in excess of 200 GeV at$\sqrt s= 630 GeV$ are studied for any non-standard physics and quantitatively compared with expectations from perturbative QCD Monte Carlo models. A corrected differential cross section is presented. A detailed examination is made of jet profiles, event jet multiplicities and the fraction of the transverse energy carried by the two jets with the highest transverse jet energies. There is good agreement with standard theory for events with transverse energies up to the largest observed values$( \approx \sqrt {s/2} )$ and the analysis shows no evidence for any non-QCD mechanism to account for the event characteristics.

1 data table

Table 1

No description provided.

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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Anti-proton - proton elastic scattering at s**(1/2) = 1020-GeV

The E710 collaboration Amos, Norman A. ; Avila, C. ; Baker, W.F. ; et al.

Nuovo Cim.A 106 (1993) 123-132, 1993.

Inspire Record 338043 DOI 10.17182/hepdata.42674

The antiproton-proton small-angle elastic-scattering distribution was measured at$\sqrt s $ GeV at the Fermilab Tevatron Collider. A fit to the nuclear-scattering distribution in the range 0.065≤|t|≤0.21 (GeV/c)2 givesb=(16.2±0.5±0.5) (GeV/c)−2 for the logarithmic slope parameter. Using the optical theorem and the luminosity from Collider parameters, we obtain σtoto(1+ρ2)1/2 =(61.7±3.7±4.4)mb.

3 data tables

Table 1

No description provided.

Table 2

Cross sections derived assuming RE(AMP)/IM(AMP) = 0.140, see Phys. Lett. B188, 143 (1987).

Table 3

Slope was derived in the t range -0.065 < t < -0.21 (GeV/c)**2.

Antiproton-proton elastic scattering at 4 GeV/c and derivation of diffraction slope at infinite energy

Czyzewski, O. ; Escoubes, B. ; Goldscmidt-Clermont, Y. ; et al.

Phys.Lett. 15 (1965) 188-191, 1965.

Inspire Record 1392865 DOI 10.17182/hepdata.837

None

4 data tables

Table 1

'1'. '2'.

Table 2

'1'.

Table 3

No description provided.

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Antiproton-proton total cross-sections between 0.575 and 5.35 GeV/c

Amaldi, U. ; Fazzini, T. ; Legros, M. ; et al.

Nuovo Cim. 34 (1964) 825-853, 1964.

Inspire Record 1185176 DOI 10.17182/hepdata.37642

Total p−p cross-section measurements have been made at 28 momenta, in the range (0.575÷5.35) GeV/c. The cross-section decreases monotonically with increasing momentum. No important irregularity has been found.

1 data table

Table 1

No description provided.