J. L. Pinfold

Publication List Details

Period

1990 - 2009

Number

210

Co-Authors

Proceedings of the workshop: HERA and the LHC workshop series on the implications of HERA for LHC physics (2009)

Jung, H., De Roeck, A., Ajaltouni, Z. J., Albino, S., Altarelli, G., Ambroglini, F., ...

2nd workshop on the implications of HERA for LHC physics. Working groups: Parton Density Functions Multi-jet final states and energy flows Heavy quarks (charm and beauty) Diffraction Cosmic Rays...

Measurement of $\alpha_{s}$ with Radiative Hadronic Events (2009)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Anagnostou, G, Anderson, K J, ...

Hadronic final states with a hard isolated photon are studied using data taken at centre-of-mass energies around the mass of the Z0 boson with the OPAL detector at LEP. The strong coupling alpha S is...

Expected Performance of the ATLAS Experiment - Detector, Trigger and Physics (2008)

Abat, E., Abbott, B., Abdallah, J., Abdelalim, A. A., Abdesselam, A., ...

A detailed study is presented of the expected performance of the ATLAS detector. The reconstruction of tracks, leptons, photons, missing energy and jets is investigated, together with the performance...

Search for Charged Higgs Bosos in $e^{+}e^{-}$ Collisions at $\sqrt{s}$ = 189-209 GeV (2008)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Anagnostou, G, Anderson, K J, ...

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...

Search for Charged Higgs Bosos in e+e- Collisions at sqrts(s) = 189-209 GeV (2008)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Anagnostou, G, Anderson, K J, ...

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...

Measurement of the quark to photon fragmentation function through the inclusive production of prompt photons in hadronic $Z^0$ decays (2008)

Ackerstaff, K, Alexander, G, Allison, J, Altekamp, N, Anderson, K J, Anderson, S, ...

The inclusive production of prompt photons with energy above 10 GeV is measured using the OPAL detector in hadronic Z^0 decays at LEP. In contrast to previous measurements, the prompt photons were...

Measurement of f(c -> D^*+ X), f(b -> D^*+ X) and Gamma_cc(bar)/Gamma_had using D^*+/- Mesons (2008)

Al, K Ackerstaff Et, Ackerstaff, K, Alexander, G, Allison, J, Altekamp, N, Anderson, K J, ...

The production rates of D^*+/- mesons in charm and bottom events at centre-of-mass energies of about 91 GeV and the partial width of primary cc(bar) pairs in hadronic Z^0 decays have been measured at...

A Measurement of the B_s^0 Lifetime using Reconstructed D_s^- Mesons (2008)

Al, K Ackerstaff Et, Ackerstaff, K, Alexander, G, Allison, J, Altekamp, N, Anderson, K J, ...

We report a measurement of the B^0_s meson lifetime from B_s^0 -> D^-_s X decays, where D_s^- mesons are reconstructed in the D_s^- -> phi pi^- and D_s^- -> K^{*0} K^- decay channels. From...

Tests of the Standard Model and Constraints on New Physics from Measurements of Fermion-pair Production at 130-172 GeV at LEP (2008)

Al, K Ackerstaff Et, Alexander, G, Allison, J, Altekamp, N, Anderson, K J, Anderson, S, ...

Production of events with hadronic and leptonic final states has been measured in e^+e^- collisions at centre-of-mass energies of 130-172 GeV, using the OPAL detector at LEP. Cross-sections and...

THE ATLAS HIGH LEVEL TRIGGER GROUP ∗ (2008)

S. Armstrong, J. T. Baines, C. P. Bee, M. Biglietti, A. Bogaerts, V. Boisvert, ...

Given the extremely high bunch crossing rate foreseen at the Large Hadron Collider (LHC) and the general-purpose nature of the ATLAS particle physics experiment, after the hardware-based first level...

Measurement of the $e^+ e^- \to W^+ W^-$ cross section and W decay branching fractions at LEP (2007)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Anagnostou, G, Anderson, K J, ...

From a total data sample of 701.1 pb^-1 recorded with e+e- centre-of-mass energies of sqrt = 161-209 GeV with the OPAL detector at LEP, 11693 W-pair candidate events are selected. These data are used...

Bose-Einstein study of position-momentum correlations of charged pions in hadronic Z0 decays (2007)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Anagnostou, G, Anderson, K J, ...

A study of Bose-Einstein correlations in pairs of identically charged pions produced in e+e- annihilations at the Z0 peak has been performed for the first time assuming a non-static emitting source....

Search for invisibly decaying Higgs bosons in $e+e- \to Zoho$ production at $\sqrt{s}$ = 183 - 209 GeV (2007)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Anagnostou, G, Anderson, K J, ...

A search is performed for Higgs bosons decaying into invisible final states, produced in association with a Zo boson in e+e- collisions at energies between 183 and 209 GeV. The search is based on...

Search for Dirac Magnetic Monopoles in $e^{+}e^{-}$ Collisions with the OPAL Detector at LEP2 (2007)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Anagnostou, G, Anderson, K J, ...

This letter describes a direct search for pair produced magnetic monopoles in e+e- collisions. The analysis is based on 62.7 pb^-1 of data collected with the OPAL detector at an average...

Inclusive Jet Production in Photon-Photon Collisions at $\sqrt{^{s}ee}$ from 189 to 209 GeV (2007)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Anagnostou, G, Anderson, K J, ...

Inclusive jet production (e+e- -> e+e- +jet+X) is studied in collisions of quasi-real photons radiated by the LEP beams at e+e- centre-of-mass energies sqrt see from 189 to 209 GeV. Jets are...

Construction, assembly and testing of the ATLAS hadronic end-cap calorimeter (2007)

Gingrich, D M, Lachat, G, Pinfold, J L, Soukup, J, Axen, D, Cojocaru, C, ...

The construction and assembly of the four wheels of the ATLAS hadronic end-cap calorimeter and their insertion into the two end-cap cryostats are described. The results of the qualification tests...

Inclusive Production of Charged Hadrons in Photon-Photon Collisions (2006)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Anagnostou, G, Anderson, K, ...

The inclusive production of charged hadrons in the collisions of quasi-real photons e+e- -> e+e- +X has been measured using the OPAL detector at LEP. The data were taken at e+e- centre-of-mass...

Search for Invisibly Decaying Higgs Bosons with Large Decay Width Using the OPAL Detector at LEP (2006)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Anagnostou, G, Anderson, K J, ...

This paper describes a topological search for an invisibly decaying Higgs boson,H, produced via the Bjorken process (e+e- -> HZ). The analysis is based on data recorded using the OPAL detector at LEP...

Implementation and performance of a tau lepton selection within the ATLAS trigger system at the LHC (2006)

Casado, M P, Dos Anjos, A, Armstrong, S, Baines, J T M, Bee, C P, Biglietti, M, ...

The ATLAS experiment at the Large Hadron Collider (LHC) has an interaction rate of up to $10^9$ Hz. The trigger must efficiently select interesting events while rejecting the large amount of...

Neutral Scalar Higgs searches using Vector Boson Fusion at ATLAS (2006)

De Jong, J K, Pinfold, J L

The Higgs boson is the last undiscovered particle predicted by the Standard Model. Its discovery is key to our understanding of the electroweak symmetry breaking process and the origin of mass. The...

Luminosity Measurement at the Large Hadron Collider (2006)

Caron, B L, Pinfold, J L

Two novel methods of measuring the luminosity delivered to the ATLAS Experiment at the CERN Large Hadron Collider experiments are presented. The production of $\mu^{+}\mu^{-}$ pair via two photon...

QCD coherence and correlations of particles with restricted momenta in hadronic Z decays (2006)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Anagnostou, G, Anderson, K J, ...

QCD coherence effects are studied based on measurements of correlations of particles with either restricted transverse momenta, pT

Precision Electroweak Measurements on the Z Resonance (2006)

Schael, S, Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Allison, J, ...

We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron-positron colliders SLC and LEP. The data consist of 17...

Search for Neutral MSSM Higgs Bosons at LEP (2006)

Schael, S, Achard, P, Adriani, O, Aguilar-Benítez, M, Alcaraz, J, Alemanni, G, ...

The four LEP collaborations, ALEPH, DELPHI, L3 and OPAL, have searched for the neutral Higgs bosons which are predicted by the Minimal Supersymmetric Standard Model (MSSM). The data of the four...

Measurement of the strong coupling $\alpha^{s}$ from four-jet observables in $e^{+}e^{-}$ annihilation (2006)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Anagnostou, G, Anderson, K J, ...

Data from e+e- annihilation into hadrons at centre-of-mass energies between 91 GeV and 209 GeV collected with the OPAL detector at LEP, are used to study the four-jet rate as a function of the Durham...

Hadronic calibration of the ATLAS liquid argon end-cap calorimeter in the pseudorapidity region 1.6 (2005)

Cojocaru, C, Pinfold, J L, Soukup, J, Vincter, M G, Datskov, V I, Fedorov, A, ...

A full azimuthal phi-wedge of the ATLAS liquid argon end-cap calorimeter has been exposed to beams of electrons, muons and pions in the energy range 6 GeV

Colour reconnection in $e^{+}e^{-}\to W^{+}W^{-}$ at $\sqrt{s}$ = 189 - 209 GeV$ (2005)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Allison, J, Amaral, P, ...

The effects of the final state interaction phenomenon known as colour reconnection are investigated at centre-of-mass energies in the range $\sqrt{s}~ 189-209 GeV using the OPAL detector at LEP....

Measurement of the mass and width of the W boson (2005)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Allison, J, Amaral, P, ...

The mass and width of the W boson are measured using e+e- -> W+W- events from the data sample collected by the OPAL experiment at LEP at centre-of-mass energies between 170 GeV and 209 GeV. The mass...

Searches for Gauge-Mediated Supersymmetry Breaking Topologies in $e^{+}e^{-}$ collisions at LEP2 (2005)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Allison, J, Amaral, P, ...

Searches were performed for topologies predicted by gauge-mediated Supersymmetry breaking models (GMSB). All possible lifetimes of the next-to-lightest SUSY particle (NLSP), either the lightest...

Determination of $\alpha_{s}$ using Jet Rates at LEP with the OPAL detector (2005)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Anagnostou, G, Anderson, K J, ...

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...

Overview of the High-Level Trigger Electron and Photon Selection for the ATLAS Experiment at the LHC (2005)

Gesualdi-Mello, A, Anjos, A, Armstrong, S, Baines, J T M, Bee, C P, Biglietti, M, ...

The ATLAS experiment at the Large Hadron Collider (LHC) will face the challenge of efficiently selecting interesting candidate events in pp collisions at 14 TeV center-of-mass energy, whilst...

Measurement of the running of the QED coupling in small-angle Bhabha scattering at LEP (2005)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Anagnostou, G, Anderson, K J, ...

Using the OPAL detector at LEP, the running of the effective QED coupling alpha(t) is measured for space-like momentum transfer through its effect on the angular spectrum of small-angle Bhabha...

Implementation and Performance of the High Level Trigger Electron and Photon Selection for the ATLAS Experiment at the LHC (2005)

Schiavi, C, Armstrong, S, Dos Anjos, A, Baines, J T M, Bee, C P, Biglietti, M, ...

The ATLAS experiment at the Large Hadron Collider (LHC) will face the challenge of efficiently selecting interesting candidate events in pp collisions at 14 TeV center of mass energy, while rejecting...

A Level-2 trigger algorithm for the identification of muons in the ATLAS Muon Spectrometer (2005)

Di Mattia, A, Armstrong, S, Dos Anjos, A, Baines, J T M, Bee, C P, Biglietti, M, ...

The ATLAS Level-2 trigger provides a software-based event selection after the initial Level-1 hardware trigger. For the muon events, the selection is decomposed in a number of broad steps: first, the...

Study of Z Pair Production and Anomalous Couplings in $e^+ e^-$ Collisions at $\sqrt{s}$ between 190 GeV and 209 GeV (2005)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Allison, J, Amaral, P, ...

A study of Z-boson pair production in e+e- annihilation at center-of-mass energies between 190 GeV and 209 GeV is reported. Final states containing only leptons, (l+l-l+l- and l+l-nn), quark and...

Measurement of event shape distributions and moments in $e^{+}e^{-} \to$ hadrons at 91-209 GeV and a determination of $\alpha_{s}$ (2004)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Allison, J, Amaral, P, ...

We have studied hadronic events from e+e- annihilation data at centre-of-mass energies from 91 to 209 GeV. We present distributions of event shape observables and their moments at each energy and...

Measurement of $R_b$ in $e^+ e^-$ Collisions at 182 - 209 GeV (2004)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Allison, J, Amaral, P, ...

Measurements of Rb, the ratio of the bbbar cross-section to the qqbar cross- section in e+e- collisions, are presented. The data were collected by the OPAL experiment at LEP at centre-of-mass...

Search for Radions at LEP2 (2004)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Allison, J, Amaral, P, ...

A new scalar resonance, called the radion, with couplings to fermions and bosons similar to those of the Higgs boson, is predicted in the framework of Randall-Sundrum models, proposed solutions to...

Portable Gathering System for Monitoring and Online Calibration at ATLAS (2004)

Conde-Muíño, P, Armstrong, S, Dos Anjos, A, Baines, J T M, Bee, C P, Biglietti, M, ...

During the runtime of any experiment, a central monitoring system that detects problems as soon as they appear has an essential role. In a large experiment, like ATLAS, the online data acquisition...

Determination of the LEP Beam Energy using Radiative Fermion-pair Events, 2004 (2004)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Allison, J, Amaral, P, ...

We present a determination of the LEP beam energy using "radiative return" fermion-pair events recorded at centre-of-mass energies from 183 GeV to 209 GeV. We find no evidence of a disagreement...

Flavour Independent $h^{0}A^{0}$ Search and Two Higgs Doublet Model Interpretation of Neutral Higgs Boson Searches at LEP (2004)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Allison, J, Amaral, P, ...

Upper limits on the cross-section of the pair-production process e+e- -> h0A0 assuming 100% decays into hadrons, are derived from a new search for the h0A0 -> hadrons topology, independent of the...

Multi-Photon Events with Large Missing Energy in $e^{+}e^{-}$ Collisions at $\sqrt{s}=192-209 GeV$ (2004)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Allison, J, Amaral, P, ...

Events with a final state consisting of two or more photons and large missing transverse energy have been observed in e+e- collisions at centre-of-mass energies in the range 192 - 209 GeV using the...

Search for neutral Higgs bosons in CP-conserving and CP-violating MSSM scenarios (2004)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Allison, J, Amaral, P, ...

This report summarizes the final results from the OPAL collaboration on searches for neutral Higgs bosons predicted by the Minimal Supersymmetric Standard Model (MSSM). CP-conserving and for the...

Scaling violations of quark and gluon jet fragmentation functions in $e^{+}e{-}$ annihilations at $\sqrt{s}$ = 91.2 and 183-209 GeV (2004)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Allison, J, Amaral, P, ...

Flavour inclusive, udsc and b fragmentation functions in unbiased jets, and flavour inclusive, udsc, b and gluon fragmentation functions in biased jets are measured in e+e- annihilations from data...

Measurement of the Strange Spectral Function in Hadronic $\tau$ Decays (2004)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Allison, J, Amaral, P, ...

Tau Lepton decays with open strangeness in the final state are measured with the OPAL detector at LEP to determine the strange hadronic spectral function of the tau lepton. The decays tau- ->...

Study of Bose-Einstein Correlations in $e^{+}e^{-}\to W^{+}W^{-}$ events at LEP (2004)

Abbiendi, G, Ainsley, C, Åkesson, T, Alexander, G, Allison, J, Amaral, P, ...

Bose-Einstein correlation between like-sign charged-particle pairs in e+e- -> W+W- events recorded with the OPAL detector at LEP at centre-of-mass energies between 183 GeV and 209 GeV are studied....

Constraints on Anomalous Quartic Gauge Boson Couplings from $\nu\overline{\nu}\gamma\gamma$ and $q\overline{q}\gamma\gamma$ events at LEP 2 (2004)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Allison, J, Amaral, P, ...

Anomalous quartic couplings between the electroweak gauge bosons may contribute to the vv gamma gamma and qq gamma gamma final states produced in e+e- collisions. This analysis uses the LEP2 OPAL...

Search for Chargino and Neutralino Production at $\sqrt{s}$ = 192-209 GeV at LEP (2004)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Allison, J, Amaral, P, ...

Approximately 438 pb-1 of e+e- data from the OPAL detector, taken with the LEP collider running at centre-of-mass energies of 192-209 Gev, are analyzed to search for evidence of chargino pair...

Implementation and performance of the event filter muon selection for the ATLAS experiment at LHC (2004)

Ventura, A., Armstrong, S., Assamagan, A., Baines, J.T.M., Bee, C.P., Bellomo, M., ...

The ATLAS trigger system is composed of three levels: an initial hardware trigger level (LVL1) followed by two software-based stages (LVL2 trigger and event filter) included in the high level trigger...

Implementation and performance of the high level trigger electron and photon selection for the ATLAS experiment at the LHC (2004)

Armstrong, S., Anjos, A.D., Baines, J.T.M., Bee, C.P., Biglietti, M., Bogaerts, J.A., ...

The ATLAS experiment at the Large Hadron Collider (LHC) will face the challenge of efficiently selecting interesting candidate events in pp collisions at 14 TeV center of mass energy, while rejecting...

Implementation and performance of the high level trigger electron and photon selection for the ATLAS experiment at the LHC (2004)

Armstrong, S., Anjos, A.D., Baines, J.T.M., Bee, C.P., Biglietti, M., Bogaerts, J.A., ...

The ATLAS experiment at the Large Hadron Collider (LHC) will face the challenge of efficiently selecting interesting candidate events in pp collisions at 14 TeV center of mass energy, while rejecting...

Implementation and performance of the event filter muon selection for the ATLAS experiment at LHC (2004)

Ventura, A., Armstrong, S., Assamagan, A., Baines, J.T.M., Bee, C.P., Bellomo, M., ...

The ATLAS trigger system is composed of three levels: an initial hardware trigger level (LVL1) followed by two software-based stages (LVL2 trigger and event filter) included in the high level trigger...

Implementation and performance of the high level trigger electron and photon selection for the ATLAS experiment at the LHC (2004)

Armstrong, S., Anjos, A.D., Baines, J.T.M., Bee, C.P., Biglietti, M., Bogaerts, J.A., ...

The ATLAS experiment at the Large Hadron Collider (LHC) will face the challenge of efficiently selecting interesting candidate events in pp collisions at 14 TeV center of mass energy, while rejecting...

Implementation and performance of the event filter muon selection for the ATLAS experiment at LHC (2004)

Ventura, A., Armstrong, S., Assamagan, A., Baines, J.T.M., Bee, C.P., Bellomo, M., ...

The ATLAS trigger system is composed of three levels: an initial hardware trigger level (LVL1) followed by two software-based stages (LVL2 trigger and event filter) included in the high level trigger...

W Boson Polarisation at LEP2 (2003)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Allison, J, Amaral, P, ...

Elements of the spin density matrix for W bosons in e+e- -> W+W- -> qqln events are measured from data recorded by the OPAL detector at LEP. This information is used calculate polarised differential...

Measurement of the partial widths of the Z into up- and down-type quarks (2003)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Allison, J, Amaral, P, ...

Using the entire OPAL LEP1 on-peak Z hadronic decay sample, Z -> qbarq gamma decays were selected by tagging hadronic final states with isolated photon candidates in the electromagnetic calorimeter....

Flavour independent search for Higgs bosons decaying into hadronic final states in e+e- collisions (2003)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Allison, J, Amaral, P, ...

A search for the Higgsstrahlung process e+e- -> hZ is described, where the neutral Higgs boson h is assumed to decay into hadronic final states. In order to be sensitive to a broad range of models,...

An Overview of the ATLAS High Level Trigger Dataflow and Supervision (2003)

Wheeler, S, Armstrong, S, Baines, J T M, Bee, C P, Biglietti, M, Bogaerts, A, ...

The ATLAS High Level Trigger (HLT) system provides software-based event selection after the initial LVL1 hardware trigger. It is composed of two stages, the LVL2 trigger and the Event Filter (EF)....

An Overview of Algorithms for the ATLAS High Level Trigger (2003)

Armstrong, S, Baines, J T M, Bee, C P, Biglietti, M, Bogaerts, A, Boisvert, V, ...

Following rigorous software design and analysis methods, an object-based architecture has been developed to derive the second- and third-level trigger decisions for the future ATLAS detector at the...

Performance of the ATLAS Hadronic End-Cap Calorimeter in Beam Tests (2003)

Dowler, B, Pinfold, J L, Soukup, J, Vincter, M G, Cheplakov, A P, Datskov, V I, ...

Modules of the ATLAS liquid argon Hadronic End-cap calorimeter (HEC) were exposed to beams of electrons, muons and pions in the energy range 6GeV

Studies for a common selection software environment in ATLAS: from the Level-2 Trigger to the offline reconstruction (2003)

Wiedenmann, W, Armstrong, S R, Baines, J T M, Bee, C P, Biglietti, M, Bogaerts, A, ...

The Atlas High Level Trigger's primary function of event selection will be accomplished with a Level-2 trigger farm and an Event Filter farm, both running software components developed in the Atlas...

Search for R-parity violating decays of sfermions at LEP (2003)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Allison, J, Amaral, P, ...

A search for pair-produced scalar fermions under the assumption that R-parity is not conserved has been performed using data collected with the OPAL detector at LEP. The data samples analysed...

Experimental studies of unbiased gluon jets from $e^{+}e^{-}$ annihilations using the jet boost algorithm (2003)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Allison, J, Amaral, P, ...

We present the first experimental results based on the jet boost algorithm, a technique to select unbiased samples of gluon jets in e+e- annihilations, i.e. gluon jets free of biases introduced by...

Tests of the Standard Model and Constraints on New Physics from Measurements of Fermion-Pair Production at 189-209 GeV at LEP (2003)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Allison, J, Amaral, P, ...

Cross-section and angular distributions for hadronic and lepton-pair final states in e+e- collisions at centre-of-mass energies between 189 GeV and 209 GeV, measured with the OPAL detector at LEP,...

A Study of $W^{+}W^{-}\gamma$ Events at LEP (2003)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Allison, J, Amaral, P, ...

A study of W+W- events accomanied by hard photon radiation produced in e+e- collisions at LEP is presented. Events consistent with being two on-shell W bosons and an isolated photon are selected from...

Search for Anomalous Production of Di-lepton Events with Missing Transverse Momentum in $e^{+}e^{-}$ Collisions at $\sqrt{s}$ = 183-209 GeV (2003)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Allison, J, Amaral, P, ...

In total 1317 di-lepton events with significant missing transverse momentum were identified in a total data sample of 680 pb-1 collected at e+e- centre-of-mass energies ranging from 183 GeV to 209...

Search for the Single Production of Doubly-Charged Higgs Bosons and Constraints on their Couplings from Bhabha Scattering (2003)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Allison, J, Amaral, P, ...

A search for single production of doubly-charged Higgs bosons has been performed using 600.7 pb^-1 of e+e- collision data with sqrt(s)=189--209GeV collected by the OPAL detector at LEP. No evidence...

A study of charm production in beauty decays with the OPAL detector at LEP (2003)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Allison, J, Amaral, P, ...

Using an inclusive method, BR(b -> D\bar{D}X) has been measured in hadronic Z^0 decays with the OPAL detector at LEP. The impact parameter significance of tracks opposite tagged b-jets is used to...

Measurement of charged current triple gauge boson couplings using W pairs at LEP (2003)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Allison, J, Amaral, P, ...

Triple gauge boson couplings are measured from W-pair and single photon events recorded by the OPAL detector at LEP at center-of-mass energies between 183 - 209 GeV with a total integrated luminosity...

Measurement of Heavy Quark Forward-Backward Asymmetries and Average B Mixing Using Leptons in Hadronic Z Decays (2003)

Abbiendi, G, Carter, A, De Wolf, E, McPherson, R A, Neal, H, Thomson, M, ...

Hadronic Z0 decays with identified electrons or muons have been used to measure the forward-backward asymmetries of e^+e^- --> Z0 --> bbbar and e^+e^- --> Z0 --> ccbar events. The asymmetries at...

Architecture of the ATLAS High Level Trigger Event Selection Software (2003)

Grothe, M, Armstrong, S, Baines, J T M, Bee, C P, Biglietti, M, Bogaerts, A, ...

The ATLAS High Level Trigger (HLT) consists of two selection steps: the second level trigger and the event filter. Both will be implemented in software, running on mostly commodity hardware. Both...

Tests of models of color reconnection and a search for glueballs using gluon jets with a rapidity gap (2003)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Allison, J, Amaral, P, ...

Gluon jets with a mean energy of 22 GeV and purity of 95% are selected from hadronic Z0 decay events produced in e+e- annihilations. A subsample of these jets is identified which exhibits a large gap...

The Algorithm Steering and Trigger Decision mechanism of the ATLAS High Level Trigger (2003)

Comune, G, Armstrong, S, Baines, J T M, Bee, C P, Biglietti, M, Bogaerts, A, ...

Given the extremely high output rate foreseen at LHC and the general-purpose nature of ATLAS experiment, an efficient and flexible way to select events in the High Level Trigger is needed. An...

Supervision of the ATLAS High Level Trigger System (2003)

Wheeler, S, Armstrong, S, Baines, J T M, Bee, C P, Biglietti, M, Bogaerts, A, ...

The ATLAS High Level Trigger (HLT) system provides software-based event selection after the initial LVL1 hardware trigger. It is composed of two stages, the LVL2 trigger and the Event Filter. The HLT...

Measurement of Isolated Prompt Photon Production in Photon-Photon Collisions at $\sqrt{s_{ee}}$=183-209 GeV (2003)

Abbiendi, G, Ainsley, C, Alexander, G, Åkesson, P F, Allison, J, Amaral, P, ...

For the first time at LEP the production of prompt photons is studied in the collisions of quasi-real photons using the OPAL data taken at e+e- centre-of-mass energies between 183 GeV and 209 GeV....

Search for pair-produced leptoquarks in $e^{+}e^{-}$ interactions at $\sqrt{s}\simeq$ 189 -209 GeV (2003)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Allison, J, Amaral, P, ...

A search for pair-produced leptoquarks is performed using e+e- collision events collected by the OPAL detector at LEP at centre-of-mass energies between 189 and 209 GeV. The data sample corresponds...

Search for a low mass CP-odd Higgs boson in $e^{+}e^{-}$ collisions with the OPAL detector at LEP2 (2002)

Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, G, Allison, J, Amaral, P, ...

We have analysed the data collected by OPAL at centre-of-mass energies between 189 and 209 GeV searching for Higgs boson candidates from the process e/sup +/e/sup -/ to h/sup 0/Z/sup 0/ followed by...

An upper limit on the anomalous magnetic moment of the $\tau$ lepton (1998)

Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, Anderson, S, ...

Using radiative Z^0 -> \tau^+ \tau^- \gamma events collected with the OPAL detector at LEP at \sqrt{s}=M_Z during 1990-95, a direct study of the electromagnetic current at the \tau\gamma vertex has...

A search for neutral Higgs bosons in the MSSM and models with two scalar field doublets (1998)

Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, Anderson, S, ...

A search is described for the neutral Higgs bosons h^0 and A^0 predicted by models with two scalar field doublets and, in particular, the Minimal Supersymmetric Standard Model (MSSM). The search in...

Search for stable and long-lived massive charged particles in $e^{+} e^{-}$ collisions at $\sqrt{s}$ = 130-183 GeV (1998)

Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, Anderson, S, ...

A search for stable and long-lived massive particles of electric charge |Q/e| = 1 or 2/3, pair-produced in e+e- collisions at centre-of-mass energies from 130 to 183 GeV, is reported by the OPAL...

Search for an excess in the production of four-jet events from $e^+ e^-$ collisions at $\sqrt{s}$ = 130-184 GeV (1998)

Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, Anderson, S, ...

Events with four distinct jets from e^+e^- collisions, collected by the OPAL detector at centre-of-mass energies between 130 and 184 GeV, are analysed for a peak in the sum of dijet masses. This...

Production of $f_{0}(980), f_{2}(1270)$ and $\phi(1020)$ in hadronic $Z^{0}$ decay (1998)

Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, Anderson, S, ...

Inclusive production of the f_0(980), f_2(1270) and \phi(1020) resonances has been studied in a sample of 4.3 million hadronic Z^0 decays from the OPAL experiment at LEP. A coupled channel analysis...

Determination of the Production Rate of $D^{*0}$ Mesons and of the Ratio V/(V+P) in $Z^{0} \to c\overline{c}$ Decays (1998)

Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, Anderson, S, ...

In e^+e^- collisions at centre-of-mass energies around 91 GeV, D^*0 mesons have been reconstructed using data collected with the OPAL detector at LEP. The hadronisation fraction has been measured to...

Measurements of the $B^{0}_s$ and $\Lambda^{0}_b$ lifetimes (1998)

Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, Anderson, S, ...

This paper presents updated measurements of the lifetimes of the B^0_s meson and the \Lambda_b baryon using 4.4 million hadronic Z^0 decays recorded by the OPAL detector at LEP from 1990 to 1995. A...

Search for charged Higgs bosons in $e^+ e^-$ collisions at $\sqrt{s}$ = 130-172 GeV (1998)

Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, Anderson, S, ...

A search is described to detect charged Higgs bosons via the process e^+e^- -> H^+H^-, using data collected by the OPAL detector at center-of-mass energies of 130-172 GeV with a total integrated...

Measurement of the one-prong hadronic $\tau$ branching ratios at LEP (1998)

Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, Anderson, S, ...

The branching ratios of the \tau^- -> h^- \nu_\tau, \tau^- -> h^- \pi^0 1991-1995 data recorded with the OPAL detector at LEP. These branching ratios are measured simultaneously using three selection...

Investigation of CP violation in $B^{0} \to J/\psi K_{s}^{0}$ decays at LEP (1998)

Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, Anderson, S, ...

An investigation of CP violation was performed using a total of 24 candidates for B^0 -> J/psi K^0_S decay, with a purity of about 60%. These events were selected from 4.4 million hadronic Z^0 decays...

Search for anomalous production of photonic events with missing energy in $e^+ e^-$ collisions at $\sqrt{s}$ = 130-172 GeV (1997)

Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, Anderson, S, ...

Photonic events with large missing energy have been observed in e+e- collisions at centre-of-mass energies of 130, 136, 161 and 172 GeV using the OPAL detector at LEP. Results are presented based on...

Search for the $B_c$ meson in hadronic $Z^0$ decays (1997)

Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, Anderson, S, ...

A search for decays of the B_c meson was performed using data collected from 1990-1995 with the OPAL detector on or near the Z peak at LEP. The decay channels B_c^+ -> J/psi pi^+, B_c^+ -> J/psi...

Search for anomalous production of dilepton events with missing transverse momentum in $e^{+} e^{-}$ collisions at $\sqrt{s}$ = 161 and 172 GeV (1997)

Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, Anderson, S, ...

Events containing a pair of charged leptons and significant missing transverse momentum are selected from a data sample corresponding to a total integrated luminosity of 20.6 pb^-1 at centre-of-mass...

Search for Unstable Heavy and Excited Leptons in $e^+ e^-$ Collisions at $\sqrt{s}$ = 170-172 GeV (1997)

Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, Anderson, S, ...

We have searched for unstable neutral and charged heavy leptons, N and L^+/-, and for excited states of neutral and charged leptons, nu*, e*, mu* and tau*, in e^+e^- collisions at centre-of-mass...

Search for a massive diphoton resonance at $\sqrt{s}$ = 91-172 GeV (1997)

Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, Anderson, S, ...

A search for the resonant production of high mass photon pairs associated with a leptonic or hadronic system has been performed using a total data sample of 25.7 pb^-1 taken at centre-of-mass...

Multi-photon final states in $e^+ e^-$ collisions at $\sqrt{s}$ = 130-172 GeV (1997)

Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, Anderson, S, ...

The process e^+e^- -> gamma gamma (gamma) is studied using data recorded with the OPAL detector at LEP. The data sample corresponds to a total integrated luminosity of 25.38 pb^{-1} taken at...

Search for the Standard Model Higgs Boson in $e^+ e^-$ Collisions at $\sqrt{s}$ = 161-172 GeV (1997)

Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, Anderson, S, ...

This paper describes a search for the Standard Model Higgs boson using data from e^+e^- collisions collected at center-of-mass energies of 161, 170 and 172 GeV by the OPAL detector at LEP. The data...

Multiplicity distributions of gluon and quark jets and tests of QCD analytic predictions (1997)

Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, Anderson, S, ...

Gluon jets are identified in e+e- hadronic annihilation events by tagging two quark jets in the same hemisphere of an event. The gluon jet is defined inclusively as all the particles in the opposite...

Polarization and forward-backward asymmetry of $\Lambda$ baryons in hadronic $Z^0$ decays (1997)

Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, Anderson, S, ...

The longitudinal polarization, the transverse polarization, and the forward-backward asymmetry of Lambda baryons have been measured using a sample of 4.34 million hadronic Z^0 decays collected with...

Search for chargino and neutralino production at $\sqrt{s}$ = 170 and 172 GeV at LEP (1997)

Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, Anderson, S, ...

A search for charginos and neutralinos, predicted by supersymmetric theories, has been performed using a data sample of 10.3 pb^-1 at centre-of-mass energies of sqrt(s) = 170 and 172 GeV with the...

Performance of an endcap prototype of the Atlas accordion electromagnetic calorimeter (1997)

Gingrich, D.M., Pinfold, J L., Boos, E., Zhautykov, B O., Aubert, B., Bazan, A., ...

The design and construction of a lead-liquid argon endcap calorimeter prototype using an accordion geometry and conceived as a sector of the inner wheel of the endcap calorimeter of the future ATLAS...

Results from a combined test of an electromagnetic liquid argon calorimeter with a hadronic scintillating-tile calorimeter (1997)

Ajaltouni, Z., Tisserand, V., Jezequel, S., Albiol, F., Alifanov, A., Amaral, P., ...

The first combined test of an electromagnetic liquid argon accordion calorimeter and a hadronic scintillating-tile calorimeter was carried out at the CERN SPS. These devices are prototypes of the...

Results from a combined test of an electromagnetic liquid argon calorimeter with a hadronic scintillating-tile calorimeter (1997)

Ajaltouni, Z., Tisserand, V., Jezequel, S., Albiol, F., Alifanov, A., Amaral, P., ...

The first combined test of an electromagnetic liquid argon accordion calorimeter and a hadronic scintillating-tile calorimeter was carried out at the CERN SPS. These devices are prototypes of the...

Performance of an endcap prototype of the Atlas accordion electromagnetic calorimeter (1997)

Gingrich, D.M., Pinfold, J L., Boos, E., Zhautykov, B O., Aubert, B., Bazan, A., ...

The design and construction of a lead-liquid argon endcap calorimeter prototype using an accordion geometry and conceived as a sector of the inner wheel of the endcap calorimeter of the future ATLAS...

Results from a combined test of an electromagnetic liquid argon calorimeter with a hadronic scintillating-tile calorimeter (1997)

Ajaltouni, Z., Tisserand, V., Jezequel, S., Albiol, F., Alifanov, A., Amaral, P., ...

The first combined test of an electromagnetic liquid argon accordion calorimeter and a hadronic scintillating-tile calorimeter was carried out at the CERN SPS. These devices are prototypes of the...

Performance of an endcap prototype of the Atlas accordion electromagnetic calorimeter (1997)

Gingrich, D.M., Pinfold, J L., Boos, E., Zhautykov, B O., Aubert, B., Bazan, A., ...

The design and construction of a lead-liquid argon endcap calorimeter prototype using an accordion geometry and conceived as a sector of the inner wheel of the endcap calorimeter of the future ATLAS...

Construction and test of a fine-grained liquid argon preshower prototype (1996)

Davis, R, Gingrich, D M, Pinfold, J L, Rodning, N L, Boos, E, Zhautykov, B O, ...

A separate liquid argon preshower detector consisting of two layers featuring a fine granularity of 2.5~10$^{\mathrm{-3}}$ was studied by the RD3 collaboration. A prototype covering approximately 0.8...