Measurement of the cross-section for the process gamma gamma --> p anti-p at s(ee)**(1/2) = 183-GeV - 189-GeV at LEP.

The OPAL collaboration Abbiendi, G. ; Ainsley, C. ; Akesson, P.F. ; et al.
Eur.Phys.J.C 28 (2003) 45-54, 2003.
Inspire Record 595836 DOI 10.17182/hepdata.48881

The exclusive production of proton-antiproton pairs in the collisions of two quasi-real photons had been studied using data taken at sqrt(s)_ee=183 GeV and 189 GeV with the OPAL detector at LEP. Results are presented for Ppbar invariant masses, W, in the range 2.15 W< <3.95 GeV. The cross-section measurements are compared with previous data and with recent analytic calculations based on the quark-diquark model.

3 data tables

Cross section as a function of the invariant mass of the pbar-p pair.

Cross section for two photon production of the pbar-p pair.

Angular distributions in 3 W ranges.


Measurement of cross-section for gamma gamma ---> p anti-p

The CLEO collaboration Artuso, M. ; He, D. ; Goldberg, M. ; et al.
Phys.Rev.D 50 (1994) 5484-5490, 1994.
Inspire Record 358510 DOI 10.17182/hepdata.47137

A measurement of the cross section for γγ→pp¯ is performed at two-photon center-of-mass energies between 2.00 and 3.25 GeV. These results are obtained using e+e−→e+e−pp¯ events selected from 1.31 fb−1 of data taken with the CLEO II detector. The measured cross section is in reasonable agreement with previous measurements and is in excellent agreement with recent calculations based on a diquark model. However, leading order QCD calculations performed using the Brodsky-Lepage formalism are well below the measured cross section.

3 data tables

Data read from graph.

Data read from graph.

Data read from graph.


Two Photon Production of Final States With a $p \bar{p}$ Pair

The ARGUS collaboration Albrecht, H. ; Bockmann, P. ; Glaser, R. ; et al.
Z.Phys.C 42 (1989) 543, 1989.
Inspire Record 267759 DOI 10.17182/hepdata.15473

Two-photon production of the exclusive final statesp\(\bar p\)+nπ (n=0, 1, 2, and 3) has been investigated using the ARGUS detector at thee+e− storage ring DORIS II at DESY. The reactionsγγ→p\(\bar p\)π andγγ→p\(\bar p\)π+π−π0 have been observed for the first time, as have theΔ++ and\(\overline {\Delta ^{ ++ } } \) baryons in the final statep\(\bar p\)π+π−. No evidence was found forΔ++\(\overline {\Delta ^{ ++ } } \) production. Topological cross sections for two-photon production ofp\(\bar p\),p\(\bar p\)π0,p\(\bar p\)π+π− andp\(\bar p\)π+π−π0, as well as the crosssection forγγ→Δ++\(\bar p\)π+π−+c.c., have been measured. Upper limits are given for the cross section forγγ→Δ0\(\overline {\Delta ^0 } \),γγ→Δ++\(\overline {\Delta ^{ ++ } } \) andγγ→Λ\(\bar \Lambda \).

7 data tables

Data read from graph.. Additional overall systematic error 13% not included.

Data read from graph.. Additional overall systematic error 13% not included.

Data read from graph.. Additional overall systematic error 13% not included.

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EXCLUSIVE PRODUCTION OF PROTON - ANTI-PROTON PAIRS IN TWO PHOTON COLLISIONS AT PEP

The TPC/Two Gamma collaboration Aihara, H. ; Alston-Garnjost, M. ; Avery, R.E. ; et al.
Phys.Rev.D 36 (1987) 3506, 1987.
Inspire Record 246557 DOI 10.17182/hepdata.23356

We report cross sections for the process γγ→pp¯ at center-of-mass energies W from 2.0 to 2.8 GeV. These results have been extracted from measurements of e+e−→e+e−pp¯ at an overall center-of-mass energy of 29 GeV, using the TPC/Two-Gamma facility at the SLAC storage ring PEP. Cross sections for the untagged mode [both photons nearly real] are shown to lie well above QCD predictions. Results are also presented for the single-tagged mode [one photon in the range 0.16<Q2<1.6 (GeV/c)2].

3 data tables

Data read from graph in preprint. Statistical errors only.

Data read from graph. Statistical errors only.

Data read from graph. Statistical errors only.


THE TPC / 2 gamma EXPERIMENT AT PEP

Bauer, Daniel A. ;
Paris Photon-Photon 1986:443, 1986.
Inspire Record 231357 DOI 10.17182/hepdata.76256
11 data tables

Data read off graph.

Data read off graph.

No description provided.

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Differential Cross-sections for $\gamma \gamma \to p \bar{p}$ in the Center-of-mass Energy Range From 2.0-{GeV} to 3.1-{GeV}

The TASSO collaboration Althoff, M. ; Braunschweig, W. ; Gather, K. ; et al.
Phys.Lett.B 130 (1983) 449-453, 1983.
Inspire Record 191417 DOI 10.17182/hepdata.6654

Exclusive production of proton-antiproton pairs by two photon scattering at CM energies between 2.0 GeV and 3.1 GeV has been measured with the TASSO detector at the e + e − storage ring PETRA. The angular distribution is flat within the accepted CM angular range | cos Θ ∗ |⩽0.7 . The integrated cross section (| cos Θ ∗ |⩽0.6) drops from about 4 nb at 2 GeV to less than 0.5 nb above 3 GeV. For the two-photon production of the η c (2984) and its subsequent decay into proton-antiproton the upper limit Γ(η c →γγ)· B (η c → p p )<0.32 keV (95% CL) is found.

5 data tables

No description provided.

No description provided.

UPPER LIMIT FOR THE PRODUCT OF THE ETA/C --> GAMMA GAMMA WIDTH AND THE BRANCHING RATIO OF ETA/C --> P AP IS DETERMINED TO BE 0.32 KEV WITH 90 PCT CL.

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