Abstract
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 ηc(2984) and its subsequent decay into proton-antiproton the upper limit Γ(ηc→γγ)·B(η c→pp)
| Original language | English (US) |
|---|---|
| Pages (from-to) | 449-453 |
| Number of pages | 5 |
| Journal | Physics Letters B |
| Volume | 130 |
| Issue number | 6 |
| DOIs | |
| State | Published - Nov 3 1983 |
| Externally published | Yes |
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics
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Differential cross sections for γγ→p-p in the CM energy range from 2.0 to 3.1 GeV. / Althoff, M.; Braunschweig, W.; Gather, K.; Kirschfink, F. J.; Lübelsmeyer, K.; Martyn, H. U.; Peise, G.; Rimkus, J.; Rosskamp, P.; Sander, H. G.; Schmitz, D.; Siebke, H.; Wallraff, W.; Fischer, H. M.; Hartmann, H.; Hillen, W.; Jocksch, A.; Knop, G.; Köpke, L.; Kolanoski, H.; Kück, H.; Wedemeyer, R.; Wermes, N.; Wollstadt, M.; Cooper, S.; Eisenberg, Y.; Hultschig, H.; Joos, P.; Koch, W.; Kötz, U.; Kowalski, H.; Ladage, A.; Löhr, B.; Lüke, D.; Mättig, P.; Mess, K. H.; Notz, D.; Pyrlik, J.; Quarrie, D. R.; Rushton, M.; Schütte, W.; Trines, D.; Wolf, G.; Xiao, Ch; Fohrmann, R.; Hilger, E.; Kracht, T.; Krasemann, H. L.; Leu, P.; Lohrmann, E.; Pandoulas, D.; Poelz, G.; Wiik, B. H.; Al-Agil, I.; Beuselinck, R.; Binnie, D. M.; Campbell, A. J.; Dornan, P. J.; Foster, B.; Garbutt, D. A.; Jones, T. D.; Jones, W. G.; McCardle, J.; Sedgbeer, J. K.; Bell, K. W.; Bowler, M. G.; Brock, I. C.; Cashmore, R. J.; Clarke, P. E.L.; Devenish, R.; Grossmann, P.; Lloyd, S. L.; Salmon, G. L.; Thomas, J.; Wyatt, T. R.; Youngman, C.; Hart, J. C.; Harvey, J.; Proudfoot, J.; Saxon, D. H.; Woodworth, P. L.; Barreiro, F.; Dittmar, M.; Heyland, D.; Holder, M.; Neumann, B.; Duchovni, E.; Karshon, U.; Mikenberg, G.; Mir, R.; Revel, D.; Ronat, E.; Shapira, A.; Yekutieli, G.; Barklow, T.; Caldwell, A.; Cherney, M.; Izen, J. M.; Mermikides, M.; Rudolph, G.; Strom, D.; Venkataramania, H.; Wicklund, E.; Wu, Sau Lan; Zobernig, G.
In: Physics Letters B, Vol. 130, No. 6, 03.11.1983, p. 449-453.Research output: Contribution to journal › Article › peer-review
}
TY - JOUR
T1 - Differential cross sections for γγ→p-p in the CM energy range from 2.0 to 3.1 GeV
AU - Althoff, M.
AU - Braunschweig, W.
AU - Gather, K.
AU - Kirschfink, F. J.
AU - Lübelsmeyer, K.
AU - Martyn, H. U.
AU - Peise, G.
AU - Rimkus, J.
AU - Rosskamp, P.
AU - Sander, H. G.
AU - Schmitz, D.
AU - Siebke, H.
AU - Wallraff, W.
AU - Fischer, H. M.
AU - Hartmann, H.
AU - Hillen, W.
AU - Jocksch, A.
AU - Knop, G.
AU - Köpke, L.
AU - Kolanoski, H.
AU - Kück, H.
AU - Wedemeyer, R.
AU - Wermes, N.
AU - Wollstadt, M.
AU - Cooper, S.
AU - Eisenberg, Y.
AU - Hultschig, H.
AU - Joos, P.
AU - Koch, W.
AU - Kötz, U.
AU - Kowalski, H.
AU - Ladage, A.
AU - Löhr, B.
AU - Lüke, D.
AU - Mättig, P.
AU - Mess, K. H.
AU - Notz, D.
AU - Pyrlik, J.
AU - Quarrie, D. R.
AU - Rushton, M.
AU - Schütte, W.
AU - Trines, D.
AU - Wolf, G.
AU - Xiao, Ch
AU - Fohrmann, R.
AU - Hilger, E.
AU - Kracht, T.
AU - Krasemann, H. L.
AU - Leu, P.
AU - Lohrmann, E.
AU - Pandoulas, D.
AU - Poelz, G.
AU - Wiik, B. H.
AU - Al-Agil, I.
AU - Beuselinck, R.
AU - Binnie, D. M.
AU - Campbell, A. J.
AU - Dornan, P. J.
AU - Foster, B.
AU - Garbutt, D. A.
AU - Jones, T. D.
AU - Jones, W. G.
AU - McCardle, J.
AU - Sedgbeer, J. K.
AU - Bell, K. W.
AU - Bowler, M. G.
AU - Brock, I. C.
AU - Cashmore, R. J.
AU - Clarke, P. E.L.
AU - Devenish, R.
AU - Grossmann, P.
AU - Lloyd, S. L.
AU - Salmon, G. L.
AU - Thomas, J.
AU - Wyatt, T. R.
AU - Youngman, C.
AU - Hart, J. C.
AU - Harvey, J.
AU - Proudfoot, J.
AU - Saxon, D. H.
AU - Woodworth, P. L.
AU - Barreiro, F.
AU - Dittmar, M.
AU - Heyland, D.
AU - Holder, M.
AU - Neumann, B.
AU - Duchovni, E.
AU - Karshon, U.
AU - Mikenberg, G.
AU - Mir, R.
AU - Revel, D.
AU - Ronat, E.
AU - Shapira, A.
AU - Yekutieli, G.
AU - Barklow, T.
AU - Caldwell, A.
AU - Cherney, M.
AU - Izen, J. M.
AU - Mermikides, M.
AU - Rudolph, G.
AU - Strom, D.
AU - Venkataramania, H.
AU - Wicklund, E.
AU - Wu, Sau Lan
AU - Zobernig, G.
N1 - Funding Information: We gratefully acknowledge the support by the DESY directorate and the PETRA machine group. We wish to thank the technical service groups at DESY and all the engineers and technicians at the collaborating institutions for their invaluable help. A large fraction of the data reduction has been done with our 168-emulators. We want to express our sincere gratitude to P. Kunz, SLAC, for his advice and assistance in this matter and for building one of the emulators. We are grateful to H. Brafman, A. Jacob and R. Yaari of the Weizmann Institute for their invaluable help in the construction, installation and testing of the 168-emulators. We are grateful to Drs. P.H. Damgaard and W. Pfeil for useful discussions. One of us (Y.E.) wishes to thank the Minna-James-Heineman Stiftung of Hannover for partial support. Those of us from outside DESY wish to thank the DESY directorate for the hospitality extended to us while working at DESY. Funding Information: First results on proton-antiproton pair production by two photon collisions via the reaction e+e e+e - p~ were presented by us in ref. \[1 \]. In this paper we present a measurement of the angular dependence and the energy behaviour of the cross section for ~'3' -~ PP obtained with an increase in statistics by a factor of 10. The results are compared with predictions of QCD \[2\]. The experiment was performed with the TASSO detector at the DESY storage ring PETRA. A description of the detector can be found elsewhere \[3\].T he data sample corresponds to an integrated luminosity of 74 pb -1 at beam energies mainly around 17 GeV taken with one of the following triggers \[4\]: (1) any two coplanar charged particles having associated signals in the inner time-of-flight counters separated by more than 154 ° in azimuth, or (2) two or more charged particles originating from the interaction region within + 15 cm along the beamline. The charged particle tracks are found in the central chambers by a hardware processor, whose track finding efficiency depends on the component IPzl of the momentum transverse to the beam direction. For the majority of the data the track finding efficiency was about 50% for tracks with transverse momenta of 0.17 GeV/c rising to 95% above 0.29 GeV/c. The trigger did not require the detection of the scattered electrons. Candidates for two-photon produced two-prong events were selected requiring two oppositely charged 1 Supported by the Deutsches Bundesministerium fiir For-schung und Technologie. 2 Now at Philips, Aachen, Germany. 3 Now at SLAC, Stanford, CA, USA. 4 On leave from Weizmann Institute, Rehovot, Israel. s Now at FNAL, Batavia, IL, USA. 6 Supported by the UK Science and Engineering Research Council. 7 Now at Carnegie-Mellon University, Pittsburg, USA. s Supported by the Minerva Gesellschaft fiir Forschung mbH. 9 Supported by the US Department of Energy contract WY-7642-02-0881.
PY - 1983/11/3
Y1 - 1983/11/3
N2 - 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 ηc(2984) and its subsequent decay into proton-antiproton the upper limit Γ(ηc→γγ)·B(η c→pp)
AB - 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 ηc(2984) and its subsequent decay into proton-antiproton the upper limit Γ(ηc→γγ)·B(η c→pp)
UR - http://www.scopus.com/inward/record.url?scp=0038152410&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0038152410&partnerID=8YFLogxK
U2 - 10.1016/0370-2693(83)91541-1
DO - 10.1016/0370-2693(83)91541-1
M3 - Article
AN - SCOPUS:0038152410
VL - 130
SP - 449
EP - 453
JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
SN - 0370-2693
IS - 6
ER -