Quark-Antiquark Energy Density Function applied to Di-Gauge Boson Production at the LHC (2008)
Alexander, Gideon, Reinherz-Aronis, Erez
In view of the start up of the 14 TeV pp Large Hadron Collider the quark anti-quark reactions leading to the final states W^+W^-, W^+-Z^0 and Z^0Z^0 are studied, in the frame workn of the Standard...
Neutral heavy lepton analysis (2005)
Akrawy, M Z, Alexander, Gideon, Allison, J, Allport, P P, Anderson, K J, Armitage, J C, ...
Bose-Einstein Correlations of $\pi^{0}$ Pairs from Hadronic $Z^{0}$ Decays (2003)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Amaral, P, ...
We observed Bose-Einstein correlation in pi0 pairs produced in Z0 decays using the data sample collected by the OPAL detector at LEP 1 from 1991 to 1995. Using a static Gaussian picture for the pion...
A Measurement of Semileptonic B Decays to Narrow Orbitally-Excited Charm Mesons (2003)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Amaral, P, ...
The decay chain b -> Bbar -> D^{**0} l nu X, D^{**0} -> D^{*+} pi^-, D^{*+} -> D^0 pi^+, D^0 ->(Kpi or K3pi) is identified in a sample of 3.9 million hadronic Z decays collected with the OPAL...
Di-Jet Production in Photon-Photon colisions at $\sqrt{s_{ee}}$ from 189 to 209 GeV (2003)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Amaral, P, ...
Di-jet producion is studied in collisions of quasi-real photons at e+e- centre- of-mass energies sqrt(s)ee from 189 to 209 GeV at LEP. The data were collected with the OPAL detector. Jets are...
A Measurement of the $\tau^{-}\to \mu^{-}\overline{\nu}_{\mu}\nu_{\tau}$ Branching Ratio (2002)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Amaral, P, ...
The tau -> mu nu nu branching ratio has been measured using data collected from 1990 to 1995 by the OPAL detector at the LEP collider. The resulting value of B(tau -> mu nu nu) = 0.1734 +-...
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Amaral, P, ...
We have measured the mean charged particle multiplicities separately for bbbar, ccbar and light quark (uubar, ddbar, ssbar) initiated events produced in e+e- annihilations at LEP. The data were...
Multi-Photon Production in $e^{+}e^{-}$ collisions at $\sqrt{s}$ = 181 - 209 GeV (2002)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Amaral, P, ...
The process e+e- -> gamma gamma (gamma) is studied using data collected by the OPAL detector at LEP between the years 1997 and 2000. The data set corresponds to an integrated luminosity of 672.3pb-1...
Search for Nearly Mass-Degenerate Charginos and Neutralinos at LEP (2002)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Amaral, P, ...
A search was performed for charginos with masses close to the mass of the lightest neutralino in e+e- collisions at centre-of-mass energies of 189-209 GeV recorded by the OPAL detector at LEP. Events...
Search for the Standard Model Higgs Boson with the OPAL Detector at LEP (2002)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Amaral, P, ...
This paper summarises the search for the Standard Model Higgs boson in e+e- collisions at centre-of-mass energies up to 209 GeV performed by the OPAL Collaboration at LEP. The consistency of the data...
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Amaral, P, ...
The b quark forward-backward asymmetry has been measured using hadronic Z0 decays collected by the OPAL experiment at LEP. Z0 -> bbbar decays were selected using a combination of secondary vertex and...
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Amaral, P, ...
The exclusive production of proton-antiproton pairs in the collisions of two quasi-real photons had been studied using data taken at sqrt(s)_ee=183 GeV and 189 GeV with the OPAL detector at LEP....
Charged Particle Momentum Spectra in $e^+ e^-$ annihilation at $\sqrt{s}$ = 192-209 GeV (2002)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Amaral, P, ...
Charged particle momentum distributions are studied in the reaction e+e- -> hadrons, using data collected with the OPAL detector at centre-of-mass energies from 192 GeV to 209 GeV. The data...
Search for scalar top and scalar bottom quarks at LEP (2002)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Amaral, P, ...
Searches for a scalar top quark and a scalar bottom quark have been performed using a data sample of 438 pb-1 at centre-of-mass energies of sqrt(s) = 192 - 209 GeV collected with the OPAL detector at...
Measurement of Neutral-Current Four-Fermion Production at LEP2 (2002)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Amaral, P, ...
Four-fermion final states qqbar e+e- and qqbar mu+mu- from neutral-current interactions in e+e- collisions are studied in the OPAL detector at LEP at centre-of-mass energies from 183 GeV to 209 GeV....
Inclusive Analysis of the b Quark Fragmentation Function in Z Decays at LEP (2002)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Amaral, P, ...
A study of b quark hadronisation is presented using inclusively reconstructed B hadrons in about four million hadronic Z decays recorded in 1992-2000 with the OPAL detector at LEP. The data are...
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Amaral, P, ...
A search is performed for production of short-lived particles in e+e- -> XY, with X -> gamma gamma and Y -> ffbar, for scalar X and scalar or vector Y. Model-independent limits in the range of 25-60...
Search for Charged Excited Leptons in $e^+ e^-$ Collisions at $\sqrt{s}$ = 183-209 GeV (2002)
Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Amaral, P, Anagnostou, G, ...
A search for charged excited leptons decaying into a lepton and photon has been performed using approximately 680 pb-1 of e+e- collision data collected by the OPAL detector at LEP at centre-of-mass...
Decay-mode independent searches for new scalar bosons with the OPAL detector at LEP (2002)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Amaral, P, ...
This paper describes topological searches for neutral scalar bosons S0 produced in association with a Z0 boson via the Bjorken process e+e- -> S0Z0 at centre-of-mass energies of 91 GeV and 183-209...
Measurement of the Charm structure Function $F_{2}^{\gamma},c$ of the Photon at LEP (2002)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Amaral, P, ...
The production of charm quarks is studied in deep-inelastic electron-photon scattering using data recorded by the OPAL detector at LEP at normal e+e- centre-of-mass energies from 183 to 209 GeV. The...
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Anagnostou, G, ...
A novel method of determining the mass of the W boson in the W+W- -> lnu lnu channel is presented and applied to 667pb^-1 of data recorded at the center-of- mass energies in the range 183-207 GeV...
Measurement of the Hadronic Photon Structure Function $F_{2}^{\gamma}$ at LEP2 (2002)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Anagnostou, G, ...
The hadronic structure of the photon F2gamma is measured as a function of Bjorken x and of the photon virtuality Q2 using deep-inelastic scattering data taken by the OPAL detector at LEP at e+e-...
Search for Leptoquarks in Electron-Photon Scattering at $\sqrt{s_{ee}}$ up to 209 GeV at LEP (2001)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Anagnostou, G, ...
Searches for first generation scalar and vector leptoquarks, and for squarks in R-parity violating SUSY models with the direct decay of the squark into Standard Model particles, have been performed...
Search for Doubly Charged Higgs Bosons with the OPAL detector at LEP (2001)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Anagnostou, G, ...
A search for pair-produced doubly charged Higgs bosons has been performed using data samples corresponding to an integrated luminosity of about 614 pb-1 collected with the OPAL detector at LEP at...
Particle multiplicity of unbiased gluon jets from $e^+ e^-$ three-jet events (2001)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Anagnostou, G, ...
The charged particle multiplicities of two- and three-jet events from the reaction e+e- -> Z0 -> hadrons are measured for Z0 decays to light quark (uds) flavors. Using recent theoretical expressions...
Search for Yukawa Production of a Light Neutral Higgs Boson at LEP (2001)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Anagnostou, G, ...
Within a Two-Higgs-Doublet Model (2HDM) a search for a light Higgs boson in the mass range of 4-12 GeV has been performed in the Yukawa process e+e- -> b bbar A/h -> b bbar tau+tau-, using the data...
Genuine Correlations of Like-Sign Particles in Hadronic $Z^0$ Decays (2001)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Anagnostou, G, ...
Correlations among hadrons with the same electric charge produced in Z0 decays are studied using the high statistics data collected from 1991 through 1995 with the OPAL detector at LEP. Normalized...
Search for Single Top Quark Production at LEP2 (2001)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Anagnostou, G, ...
A search for single top quark production via flavour changing neutral currents (FCNC) was performed with data collected by the OPAL detector at the e+e- collider LEP. Approximately 600 pb-1 of data...
Measurement of the Hadronic Cross-Section for the Scattering of Two Virtual Photons at LEP (2001)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Anagnostou, G, ...
The interaction of virtual photons is investigated using the reaction e+e- -> e+e- hadrons based on data taken by the OPAL experiment at e+e- centre-of-mass energies sqrt(s_ee)=189-209 GeV, for W>5...
Measurement of $Z/\gamma^{*}$ production in Compton scattering of quasi-real photons (2001)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Anagnostou, G, ...
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...
Determination of the b Quark Mass at the Z Mass Scale (2001)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Anagnostou, G, ...
In hadronic decays of Z bosons recorded with the OPAL detector at LEP, events containing b quarks were selected using the long lifetime of b flavoured hadrons. Comparing the 3-jet rate in b events...
Search for Lepton Flavour Violation in $e^+e^-$ Collisions at $\sqrt{s}$ = 189 - 209 GeV (2001)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Anagnostou, G, ...
We search for lepton flavour violating events (e mu, e tau and mu tau) that could be directly produced in e+e- annihilations, using the full available data sample collected with the OPAL detector at...
Measurement of the Branching Ratio for the Process $b \to \tau^{-}\overline{\nu}_{\tau}X$ (2001)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Anagnostou, G, ...
The inclusive branching ratio for the process b -> tau nu X has been measured using hadronic Z decays collected by the OPAL experiment at LEP in the years 1992-2000. The result is: BR(b -> tau nu X)...
Angular Analysis of the Muon Pair Asymmetry at LEP 1 (2001)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Anagnostou, G, ...
Data on muon pair production obtained by the OPAL collaboration at centre of mass energies near the Z peak are analysed. Small angular mismatches between the directions of the two muons are used to...
Measurement of |$V_{ub}$| using b hadron semileptonic decays (2001)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Anagnostou, G, ...
The magnitude of the CKM matrix element Vub is determined by measuring the inclusive charmless semileptonic branching fraction of beauty hadrons at OPAL based on b -> Xu l nu event topology and...
Abbiendi, G, Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, ...
A search for first generation scalar and vector leptoquarks (LQ) as well as for squarks in R-parity violating SUSY models has been performed using e+e- collisions collected with the OPAL detector at...
Precision Neutral Current Asymmetry Parameter Measurements from the Tau Polarization at LEP (2001)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Anagnostou, G, ...
Measurements of the tau lepton polarization and forward-backward polarization asymmetry near the Z resonance using the OPAL detector are described. The measurements are based on analyses of tau -> e...
Measurement of the Branching Ratio for $D_{s} \to \tau\nu_{\tau}$ Decays (2001)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Anagnostou, G, ...
Using about 3.9 million hadronic Z decays from e+e- collisions recorded by the OPAL detector at LEP at centre-of-mass energies near MZ the branching ratio for the decay D_s -> tau nu_tau has been...
Mass and Transverse Mass Effects on the Hadron Emitter Size (2001)
We investigate the dependence of the longitudinal emitter dimension of identical bosons, produced in the hadronic Z$^0$ decays, on their transverse mass obtained from 2-dimensional Bose-Einstein...
A Simultaneous Measurement of the QCD Colour Factors and the Strong Coupling (2001)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Anagnostou, G, ...
Using data from e+e- annihilation into hadrons, taken with the OPAL detector at LEP at the Z pole between 1991 and 1995, we performed a simultaneous measurement of the colour factors of the...
A Search for a Narrow Radial Excitation of the $D^{*\pm}$ Meson (2001)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Anagnostou, G, ...
A sample of 3.73 million hadronic Z decays, recorded with the OPAL detector at LEP in the years 1991-95, has been used to search for a narrow resonance corresponding to the decay of the D*'+/-(2629)...
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Anagnostou, G, ...
A search for the Standard Model Higgs boson has been performed with the OPAL detector at LEP based on the full data sample collected at sqrt(s) = 192-209 GeV in 1999 and 2000, corresponding to an...
Precise Determination of the Z Resonance Parameters at LEP: Zedometry (2000)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Anagnostou, G, ...
This final analysis of hadronic and leptonic cross-sections and of leptonic forward-backward asymmetries in e+e- collisions with the OPAL detector makes use of the full LEP1 data sample comprising...
A Study of $B_{s}$ Meson Oscillation Using $D_{s}^{-}$-Lepton Correlations (2000)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Anagnostou, G, ...
From data collected around the Z resonance by the OPAL detector at LEP a sample of Bs decays was obtained using Ds^-l^+ combinations, where the Ds^- was fully reconstructed in the phi pi-, K*0K- and...
Charged Multiplicities in Z Decays into u, d, and s Quarks (2000)
Abbiendi, G, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, Anagnostou, G, ...
About 4.4 million hadronic decays of Z bosons, recorded by the OPAL detector at LEP at a centre-of-mass energy of around sqrt(s) = 91.2 GeV, are used to determine the mean charged particle...
Abbiendi, G, Ackerstaff, K, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, ...
The rates are measured per hadronic Z decay for gluon splitting to bb(bar) quark pairs, g_bb, and of events containing two bb(bar) quark pairs, g_4b, using a sample of four-jet events selected from...
Abbiendi, G, Abbiendi, G, Ackerstaff, K, Ainsley, C, Alexander, Gideon, Allison, J, ...
From about 4 million hadronic Z decays recorded by the OPAL detector on and near to the Z resonance, we select a sample of more than 570000 inclusively reconstructed B mesons. Orbitally-excited...
Abbiendi, G, Ackerstaff, K, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, ...
The lifetime and oscillation frequency of the B0 meson has been measured using B0->D*+l-v decays recorded on the Z0 peak with the OPAL detector at LEP. The D*+ -> D0pi+ decays were reconstructed...
Abbiendi, G, Ackerstaff, K, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, ...
A measurement of triple gauge boson couplings is presented, based on W-pair data recorded by the OPAL detector at LEP during 1998 at a centre-of-mass energy of 189 GeV with an integrated luminosity...
Abbiendi, G, Ackerstaff, K, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, ...
From a data sample of 183 pb^-1 recorded at a center-of-mass energy of roots = 189 GeV with the OPAL detector at LEP, 3068 W-pair candidate events are selected. Assuming Standard Model W boson decay...
A Measurement of the Rate of Charm Production in W Decays (2000)
Abbiendi, G, Ackerstaff, K, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, ...
Using data recorded at centre-of-mass energies around 183 GeV and 189 GeV with the OPAL detector at LEP, the fundamental coupling of the charm quark to the W boson has been studied. The ratio Rc^W =...
Abbiendi, G, Ackerstaff, K, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, ...
Measurements are presented of the polarisation of W+W- boson pairs produced in e+e- collisions, and of CP-violating WWZ and WWGamma trilinear gauge couplings. The data were recorded by the OPAL...
A Study of One-Prong Tau Decays with a Charged Kaon (2000)
Abbiendi, G, Ackerstaff, K, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, ...
From an analysis of the ionisation energy loss of charged particles selected from 110326 e+e- -> tau+tau- candidates recorded by the OPAL detector at e+e- centre-of-mass energies near the Z0...
Measurement of the Mass and Width of the W Boson in $e^{+}e^{-}$ Collisions at 189 GeV (2000)
Abbiendi, G, Ackerstaff, K, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, ...
The mass and width of the W boson are determined in e+e- collisions at LEP using 183 pb^-1 of data recorded at a centre-of-mass energy roots=189 GeV with the OPAL detector. The invariant mass...
The many sources effect on the genuine multihadron correlations (2000)
Alexander, Gideon, Sarkisyan-Grinbaum, E
Here we report on a study aimed to explore the dependence of the genuine multiparticle correlations on the number of sources while the influence of other possible factors affecting the multihadron...
Two Higgs Doublet Model and Model Independent Interpretation of Neutral Higgs Boson Searches (2000)
Abbiendi, G, Ackerstaff, K, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, ...
Searches for the neutral Higgs bosons h0 and A0, are used to obtain limits on the Type II Two Higgs Doublet Model (2HDM(II)) with no CP-violation in the Higgs sector and no additional particles...
Abbiendi, G, Ackerstaff, K, Ainsley, C, Åkesson, P F, Alexander, Gideon, Allison, J, ...
The inclusive production rate of phi mesons from the decay of b hadrons produced in Z0 decays was measured to be Br(b->phi+X) = 0.0282+-0.0013(stat.)+-0.0019(syst.), using data collected by the OPAL...