Measurement of Z / gamma* production in Compton scattering of quasi-real photons.

The OPAL collaboration Abbiendi, G. ; Ainsley, C. ; Akesson, P.F. ; et al.
Eur.Phys.J.C 24 (2002) 1-15, 2002.
Inspire Record 560307 DOI 10.17182/hepdata.49750

The process e+ e- -> e+ e- Z/gamma* is studied with the OPAL detector at LEP at a centre of mass energy of sqrt(s) = 189 GeV. The cross-section times the branching ratio of the Z/gamma* decaying into hadrons is measured within Lorentz invariant kinematic limits to be (1.2 +/- 0.3 +/- 0.1) pb for invariant masses of the hadronic system between 5 GeV and 60 GeV and (0.7 +/- 0.2 +/- 0.1) pb for hadronic masses above 60 GeV. The differential cross-sections of the Mandelstam variables s-hat, t-hat, and u-hat are measured and compared with the predictions from the Monte Carlo generators grc4f and PYTHIA. From this, based on a factorisation ansatz, the total and differential cross-sections for the subprocess e gamma -> e Z/gamma* are derived.

9 data tables

Measured values of the cross section times the branching ratio for the (Z0/GAMMA*) decay into hadrons within the restricted kinematic limits.

Differential cross-section dsig_ee/dm_qq.

Differential cross-section dsigma_ee/dsqrt(shat).

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A Study of the Reactions $K^- p \to \Lambda \pi^0$, $\Lambda \eta$, $\Lambda \eta^\prime$ at 8.25-{GeV}/$c$ Incident $K^-$ Momentum

The Birmingham-CERN-Glasgow-Michigan State-Paris collaboration Al-Harran, S. ; Baubillier, M. ; Bloodworth, I.J. ; et al.
Nucl.Phys.B 183 (1981) 269-294, 1981.
Inspire Record 155276 DOI 10.17182/hepdata.34295

Differential cross sections and polarizations are presented for the reactions K − p → Λπ 0 , Λη , Λη ′ at 8.25 GeV/ c incident K − momentum. The data, which come from a high statistics experiment in the CERN 2 m bubble chamber, are compared with previous experimental results on the same reactions and with current theoretical ideas.

11 data tables

No description provided.

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Measurement of the Baryon Exchange Reactions $K^- p \to \Lambda \eta$, $K^- p \to \Lambda \pi^0$ at 6-{GeV}/$c$ and the Value of the $\eta N N$ Coupling Constant

Becker, H. ; Blanar, G. ; Blum, W. ; et al.
Nucl.Phys.B 167 (1980) 292-306, 1980.
Inspire Record 143463 DOI 10.17182/hepdata.43413

In order to determine the ηNN coupling constant we have measured the two reactions K − p→ Λη and K − p→ Λπ 0 with a magnetic wire chamber spectrometer which contained a gamma counter for the γγ decays of π 0 and η. The Λ polarization and the differential cross sections are given. The latter have quite different u dependences. Their ratio is interpreted, in terms of a nucleon-Regge exchange model, as the effect of a small ηNN coupling constant for which we obtain G η NN 2 = G π NN 2 · (0.26 ± 0.10) as allowed by SU(3). The large value given by Heisenberg's non-linear field theory, G η NN 2 = G π NN 2 · 0.9, is excluded by this measurement if the characteristic u dependence of the Λπ 0 channel is attributed to N α Regge exchange.

4 data tables

Axis error includes +- 10/10 contribution.

No description provided.

Axis error includes +- 10/10 contribution.

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