Multijets in photoproduction at HERA

The ZEUS collaboration Gwenlan, C. ;
Acta Phys.Polon.B 33 (2002) 3123-3128, 2002.
Inspire Record 602140 DOI 10.17182/hepdata.51400

Cross-sections for the photoproduction of events containing four high-$E_{\rm T}$ jets have been measured with the ZEUS detector using an integrated luminosity of 38.7 pb$^{-1}$. At low invariant mass of the four-jet system, $m_{\rm 4J}$, the observed event distributions are sensitive to the underlying event model. The inclusion of multi-parton interactions in Monte Carlo simulations lead to a significantly better description of the data. For $m_{\rm 4J} > 50 $ GeV the data is adequately described by models with no simulation of an underlying event, suggesting that this is a kinematic region suitable for comparison with perturbative QCD calculations.

7 data tables

The measured normalised costheta3 distributions.

The measured normalised psi3 distributions.

The measured normalised X3 distributions.

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Study of double-tagged gamma gamma events at LEP II.

The DELPHI collaboration Abdallah, J. ; Abreu, P. ; Adam, W. ; et al.
Eur.Phys.J.C 46 (2006) 559-568, 2006.
Inspire Record 704268 DOI 10.17182/hepdata.48974

Double-tagged interactions of photons with virtualities Q^2 between 10 GeV^2 and 200 GeV^2 are studied with the data collected by DELPHI at LEPII from 1998 to 2000, corresponding to an integrated luminosity of 550 pb^{-1}. The gam* gam* -> mu+mu- data agree with QED predictions. The cross-section of the reaction gam* gam* -> hadrons is measured and compared to the LO and NLO BFKL calculations.

4 data tables

Measured cross section for the process E+ E- --> E+ E- HADRONS.

Measured cross section for the process GAMMA* GAMMA* --> HADRONS.

Differential cross section for GAMMA* GAMMA* --> MU+ MU-.

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Study of hadronic final states from double tagged gamma gamma events at LEP.

The ALEPH collaboration Heister, A. ; Schael, S. ; Barate, R. ; et al.
CERN-EP-2003-025, 2003.
Inspire Record 619958 DOI 10.17182/hepdata.49702

The interaction of virtual photons is investigated using double tagged gammagamma events with hadronic final states recorded by the ALEPH experiment at e^+e^- centre-of-mass energies between 188 and 209 GeV. The measured cross section is compared to Monte Carlo models, and to next-to-leading-order QCD and BFKL calculations.

10 data tables

Differential cross section as a function of the relative energy of the scattered electrons.

Differential cross section as a function of the polar angle THETA of the scattered electrons.

Differential cross section as a function of the virtuality Q**2 of the photons.

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Kaon Production at 200-{GeV} and 900-{GeV} Center-of-mass Energy

The UA5 collaboration Ansorge, R.E. ; Asman, B. ; Booth, C.N. ; et al.
Phys.Lett.B 199 (1987) 311-316, 1987.
Inspire Record 254608 DOI 10.17182/hepdata.30057

Results on inclusive kaon production at 200 and 900 GeV centre of mass (CM) energy obtained with the UA5 detector at the pulsed CERN SPS antiproton-proton Collider are presented and compared with our earlier data at 546 GeV. The average transverse momentum 〈 p t 〉 of kaons has been estimated to be (0.50±0.04) GeV/ c at 200 GeV and (0.63±0.03) GeV/ c at 900 GeV in the central region and shows an increase with CM energy that is smore rapid than that expected from previous ISR data. The yield of kaons per inelastic p p event is found to be (0.72±0.12) at 200 GeV and (1.31±0.14) at 900 GeV. Finally, the K/π ratio has been found to exhibit a very slow increase with CM energy.

1 data table

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