P. Scharff-Hansen

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The Data Acquisition (DAQ) of the CMS Experiment [1] is composed by O(10000) network objects spread in O(1000) nodes, most of them based on commodity PCs, connected to a very efficient Local Area Network. The DAQ complex (both hardware and software) must be controlled in order to synchronize all the objects to perform in the proper sequence the needed(More)
QCD coherence effects are studied based on measurements of correlations of particles with either restricted transverse momenta, pT < p cut T , where pT is defined with respect to the thrust axis, or restricted absolute momenta, p ≡ |p| < p , using about four million hadronic Z decays recorded at LEP with the OPAL detector. The correlations are analyzed in(More)
Searches for a scalar top quark and a scalar bottom quark have been performed using a data sample of 438 pb at centre-of-mass energies of √ s =192 – 209 GeV collected with the OPAL detector at LEP. No evidence for a signal was found. The 95% confidence level lower limit on the scalar top quark mass is 97.6 GeV if the mixing angle between the supersymmetric(More)
Bose-Einstein Correlations (BEC) of three identical charged pions were studied in 4× 106 hadronic Z0 decays recorded with the OPAL detector at LEP. The genuine three-pion correlations, corrected for the Coulomb effect, were separated from the known two-pion correlations by a new subtraction procedure. A significant genuine three-pion BEC enhancement near(More)
G. Abbiendi, C. Ainsley, P. F. Åkesson, G. Alexander, J. Allison, P. Amaral, G. Anagnostou, K. J. Anderson, S. Asai, D. Axen, G. Azuelos, I. Bailey, E. Barberio, T. Barillari, R. J. Barlow, R. J. Batley, P. Bechtle, T. Behnke, K. W. Bell, P. J. Bell, G. Bella, A. Bellerive, G. Benelli, S. Bethke, O. Biebel, O. Boeriu, P. Bock, M. Boutemeur, S. Braibant, L.(More)
The process ee → eeZ/γ is studied with the OPAL detector at LEP at a centre of mass energy of √ s = 189 GeV. The cross-section times the branching ratio of the Z/γ 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(More)
Bose-Einstein Correlations (BEC) of three identical charged pions were studied in 4× 106 hadronic Z0 decays recorded with the OPAL detector at LEP. The genuine three-pion correlations, corrected for the Coulomb effect, were separated from the known two-pion correlations by a new subtraction procedure. A significant genuine three-pion BEC enhancement near(More)
A search is made for charged Higgs bosons predicted by Two-Higgs-Doublet extensions of the Standard Model (2HDM) using electron-positron collision data collected by the OPAL experiment at √ s = 189–209 GeV, corresponding to an integrated luminosity of approximately 600 pb−1. Charged Higgs bosons are assumed to be pairproduced and to decay into qq̄, τντ or(More)
G. Abbiendi, C. Ainsley, P. F. Åkesson, G. Alexander, J. Allison, P. Amaral, G. Anagnostou, K. J. Anderson, S. Arcelli, S. Asai, D. Axen, G. Azuelos, I. Bailey, E. Barberio, T. Barillari, R. J. Barlow, R. J. Batley, P. Bechtle, T. Behnke, K.W. Bell, P.J. Bell, G. Bella, A. Bellerive, G. Benelli, S. Bethke, O. Biebel, O. Boeriu, P. Bock, M. Boutemeur, S.(More)
Hadronic events produced in e+e− collisions by the LEP collider and recorded by the OPAL detector were used to form distributions based on the number of reconstructed jets. The data were collected between 1995 and 2000 and correspond to energies of 91 GeV, 130-136 GeV and 161-209 GeV. The jet rates were determined using four different jet-finding algorithms(More)