The trigger system of the OPAL experiment at LEP

Arignon, M.; Ball, A. H.; Bell, K. W.; Bramhall, M.; Braun, Annette F.; Carter, A.A.; Carter, J.R.; Charlton, D. G.; Dittmar, M.; Farthouat, P.; Feyt, J.; Gao, Haixiang; Gary, J. W.; Gillies, J. D.; Greiner, Carolin; Hammarstroem, R.; Hart, J.C.; Heuer, R. D.; Hill, J. C.; Hillier, S. J.; Hilse, T.; Humbert, R.; Jaroslawski, S.; Joos, D.; Jovanović, P.; Kimura, Takashi; Kellogg, R. G.; Kobayashi, T.; Dû, P. Le; Levinson, L. J.; Loebinger, F. K.; Macbeth, A. A.; Mikenberg, G.; Milborrow, R.; Pawley, S. J.; Penton, A.; Pritchard, T. W.; Quast, G.; Ricth, G.; Roach, C. M.; Runge, K.; Schaile, O.; Scherer, Dominik; Schuler, G.; Schwarz, J.; Springer, R. W.; Takeda, Hiroshi; Virtue, C. J.; Wagner, A.; Ward, D. R.; Watkins, P. M.; Webel, M.; Weber, C.; Weymann, M.; Wilson, G. W.; Wilson, J. A.

doi:10.1016/0168-9002(92)90087-k

Cited by 44 publications

(14 citation statements)

References 22 publications

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“…This will replace the current simple algorithm which ignores multiple scattering and assumes a constant magnetic field everywhere. Initial work is described in the D-Zero notes below [4,6]. A program for muon momentum measurement is now working for all regions of the LAMUS detector, and is in process of integration into the D-Zero reconstruction package.…”

Section: Softwarementioning

confidence: 99%

“…The EMC and BCDMS have published high precision measurements on the structure function F2(x,Q ) measured using hydrogen [1,2] and deuterium [3,4] targets.…”

Section: Cernmentioning

confidence: 99%

“…[4] The trigger system, involving singleelement triggers and coincidences in 6 -4 bins between different detector elements, provides triggers for all the main physics processes at close to 100% efficiency, and the large number of redundant triggers makes it possible to evaluate systematics precisely. During the 1990 running, OPAL triggered at an average rate of 2 Hz, of which 0.12 Hz came from multihadron events, 0.2 Hz from forward detector bhabhas, 0.02 Hz from dilepton events, 0.6 Hz from cosmics and noise, and the remainder from a variety of junk sources such as beam-gas, beam-wall, halo muons, synchrotron radiation, and off-momentum particles.…”

Section: Trigger and Readoutmentioning

confidence: 99%

“…The Vax system is an on-going project and it is planned to have this operational in time for the collider run in early 1992. [2], PYTHIA [3] and I-€ERWIG [4].…”

Section: Softwarementioning

confidence: 99%

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Hadron collider physics at UCR

Kernan¹,

Shen²

1997

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The first run of D-Zero at the Fermilab Tevatron will start in early 1992. The central part of the detector is assembled (transition radiation detector, central tracking chambers, central calorimeters, and central muon chambers) and was commissioned in a cosmic ray run in Spring 1991. The North endcap (calorimeter plus muon spectrometer) will be commissioned in August, the South endcap in December. The current schedule calls for 'roll-in' of the completed detector in February 1992.Our major effort in the coming year will be concentrated on muon detection in DZero. K. Bazizi is leading the effort to implement the muon trigger. A. Klatchko will be responsible for muon momentum analysis. T. Huehn will measure the inclusive do/dp, distribution as his Ph.D. thesis project. This measurement has several objectives: (i) to verify muon detection efficiency, (ii) to measure the b-quark production cross section and (iii) to account for known muon sources as a first step in searching for new phenomena involving leptons, in particular the top quark. R. H a l l will search for strong production of the top quark for his Ph.D. thesis project. The search will be based on the decay E+ W'W-b6 with the two W s decaying into ev and pv respectively.Other D-Zero data analysis activities include continuation of the systematic study of Monte Carlo event generators with p d c u l a r emphasis on the associated production of Ws and jets: this reaction, in addition to its intrinsic interest, constitutes the major background to tt decaying to a single lepton plus jets. A search for W + y events in the D-Zero data will be initiated, with the goal of measuring the W magnetic moment.Planning is well underway for an extensive upgrade of the D-Zero detector. This is necessitated by anticipated increases in luminosity and the associated reduction in beam crossing times from 3.4 ps to 0.4 ps. The major changes involve replacement of the central and forward tracking by a silicon microstrip detector covering the rapidity range q < 2 and surrounded by a scintillating fiber tracker. This tracking system will be enclosed in a 1.5 T 1 magnetic field. The UCR group (Ellison, Joyce, Wimpenny)), in collaboration with LBL and Fermilab, are designing the silicon tracker. In particular UCR will be responsible for surveying the properties of commercially available silicon detectors in order to establish specifications for these elements.We are also doing R&D for the SDC silicon tracker. Studies on radiation damage effects carried out in collaboration with UC Santa Cruz and Lss Alamos, were presented by J. Ellison at the 2nd London Conference on Position Sensilive Detectors, Sept. 1990. Future efforts will be divided between the ongoing radiation damage studies and work on the SDC silicon tracker forward disks. Prototype wedge detectors will be acquired from vendors and we will evaluate their perfurmance at UCR using a variety of signal generation techniques.Work on the phenomenology of the nucleon structure functions is in progress.

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Section: Softwarementioning

confidence: 99%

“…The EMC and BCDMS have published high precision measurements on the structure function F2(x,Q ) measured using hydrogen [1,2] and deuterium [3,4] targets.…”

Section: Cernmentioning

confidence: 99%

Section: Trigger and Readoutmentioning

confidence: 99%

“…The Vax system is an on-going project and it is planned to have this operational in time for the collider run in early 1992. [2], PYTHIA [3] and I-€ERWIG [4].…”

Section: Softwarementioning

confidence: 99%

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Hadron collider physics at UCR

Kernan¹,

Shen²

1997

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“…The OPAL detector, 25 trigger and data acquisition system are fully described elsewhere [4][5][6][7][8]. The data used for the present analysis were collected between 1997 and 2000, at centre-of-mass energies in the range from 183 GeV to 209 GeV.…”

Section: Data and Monte Carlo Samplesmentioning

confidence: 99%

Determination of the LEP beam energy using radiative fermion-pair events

et al. 2004

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We present a determination of the LEP beam energy using "radiative return" fermion-pair events recorded at centre-of-mass energies from 183 to 209 GeV. We find no evidence of a disagreement between the OPAL data and the LEP Energy Working Group's standard calibration. Including the energy-averaged 11 MeV uncertainty in the standard determination, the beam energy we obtain from the OPAL data is higher than that obtained from the LEP calibration by 0 ± 34(stat.) ± 27(syst.) MeV.

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QCD studies using a cone-based jet finding algorithm fore + e ? collisons at LEP

Akers¹,

Alexander²,

Allison³

et al. 1994

Z. Phys. C - Particles and Fields

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We describe a cone-based jet nding algorithm (similar to that used in pp experiments), which we have applied to hadronic events recorded using the OPAL detector at LEP. Comparisons are made between jets de ned with the cone algorithm and jets found by the \JADE" and \Durham" jet nders usually used in e + e experiments. Measured jet rates, as a function of the cone size and as a function of the minimum jet energy, have been compared with O( 2 s ) QCD calculations, from which two complementary measurements of s (M Z 0 ) have been made. The results are s (M Z 0 ) = 0:116 0:008 and s (M Z 0 ) = 0:119 0:008 respectively, where the errors include both experimental and theoretical uncertainties. Measurements are presented of the energy ow inside jets de ned using the cone algorithm, and compared with equivalent data from pp interactions, reported by the CDF collaboration. We nd that the jets in e + e are signi cantly narrower than those observed in pp. The main contribution to this e ect appears to arise from di erences between quark-and gluon-induced jets.

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The trigger system of the OPAL experiment at LEP

Cited by 44 publications

References 22 publications

Hadron collider physics at UCR

Hadron collider physics at UCR

Determination of the LEP beam energy using radiative fermion-pair events

QCD studies using a cone-based jet finding algorithm fore + e ? collisons at LEP

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