N. Altekamp

Publication List Details

Period

1995 - 2008

Number

300

Co-Authors

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...

(Submitted to European Physical Journal, C) The OPAL Collaboration (2007)

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

Bose-Einstein Correlations (BEC) of three identical charged pions were studied in 4 × 10 6 hadronic Z 0 decays recorded with the OPAL detector at LEP. The genuine three-pion correlations, corrected...

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...

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...

A study of $B^{0}_{s}$ meson oscillation using hadronic $Z^{0}$ decays containing leptons (1999)

Abbiendi, G, Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, ...

A sample of Z decays containing b-flavoured hadrons is tagged using leptons, and events having precise proper time measurements are selected. These events are used to study Bs oscillations. using the...

Search for Higgs Bosons and Other Massive States decaying into two Photons in $e^{+}e^{-}$ Collisions at 189 GeV (1999)

Abbiendi, G, Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, ...

A search is described for the generic process e+e- to X Y, where X is a neutral heavy scalar boson decaying into a pair of photons, and Y is a neutral heavy boson (scalar or vector) decaying into a...

A Study of Spin Alignment of $\rho(770)^{\pm}$ and $\omega(782)$ Mesons in Hadronic $Z^{0}$ Decays (1999)

Abbiendi, G, Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, ...

The helicity density matrix elements rho[00] of rho(770)+- and omega(782) mesons produced in Z decays have been measured using the OPAL detector at LEP. Over the measured meson energy range, the...

Measurements of inclusive semileptonic branching fractions of b hadrons in $Z^{0}$ decays (1999)

Abbiendi, G, Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, ...

A measurement of inclusive semileptonic branching fractions of b hadrons produced in Z decays is presented. An enriched Z -> bbbar sample is obtained with a lifetime flavour-tagging technique. The...

Total Hadronic Cross-Section of Photon-Photon Interactions at LEP (1999)

Abbiendi, G, Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, ...

The total hadronic cross-section sigma_gg(W) for the interaction of real photons, gg->hadrons, is measured for gg centre-of-mass energies 10 e+e- hardrons, using a luminosity function for the photon...

Search for R-Parity Violating Decays of Scalar Fermions at LEP (1999)

Abbiendi, G, Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, ...

A search for pair produced scalar fermions with couplings that violate R-parity has been performed using a data sample corresponding to an integrated luminosity of 56 pb-1 at a centre-of-mass energy...

Test of the Flavour Independence of $\alpha_{s}$ using Next-to-Leading Order Calculations for Heavy Quarks (1999)

Abbiendi, G, Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, ...

We present a test of the flavour independence of the strong coupling constant for charm and bottom quarks with respect to light (uds) quarks, based on a hadronic event sample obtained with the OPAL...

Search for Scalar Top and Scalar Bottom Quarks at $\sqrt{s}$ = 189 GeV at LEP (1999)

Abbiendi, G, Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, ...

Searches for a scalar top quark and a scalar bottom quark have been performed using a data sample of 182 pb-1 at a centre-of-mass energy of 189 GeV collected with the OPAL detector at LEP. No...

Experimental properties of gluon and quark jets from a point source (1999)

Abbiendi, G, Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, ...

Gluon jets are identified in hadronic Z0 decays as all the particles in a hemisphere opposite to a hemisphere containing two tagged quark jets. Gluon jets defined in this manner are equivalent to...

Intermittency and correlations in hadronic $Z^0$ decays (1999)

Abbiendi, G, Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, ...

A multidimensional study of local multiplicity fluctuations and multiparticle correlations of hadrons produced in Z decays is performed. The study is based on the data sample of more than 4 million...

Measurements of the QED Structure of the Photon (1999)

Abbiendi, G, Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, ...

The structure of both quasi-real and highly virtual photons is investigated using the reaction e+e- -> e+e-mu+mu-, proceeding via the exchange of two photons. The results are based on the complete...

Searches for R-Parity Violating Decays of Gauginos at 183 GeV at LEP (1999)

Abbiendi, G, Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, ...

Searches for pair-produced charginos and neutralinos with R-parity violating decays have been performed using a data sample corresponding to an integrated luminosity of 56 pb-1 collected with the...

Measurement of the W Mass and Width in $e^{+}e^{-}$ Collisions at 183 GeV (1999)

Abbiendi, G, Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, ...

Using a data sample of 57 pb-1 recorded at a centre-of-mass energy of 183 GeV with the Opal detector at LEP, 282 W+W- -> qqqq and 300 W+W- -> qqlnu candidate events are used to obtain a measurement...

Colour reconnection studies in $e^{+}e^{-} \to W^{+}W^{-}$ at $\sqrt{s}$=183 GeV (1999)

Abbiendi, G, Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, ...

The predicted effects of final state interactions such as colour reconnection are investigated by measuring properties of hadronic decays of W bosons, recorded at a centre-of-mass energy of...

Measurement of the $B^{+}$ and $B^{0}$ lifetimes and search for CP(T) violation using reconstructed secondary vertices (1999)

Abbiendi, G, Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, ...

The lifetimes of the B+ and B0 mesons, and their ratio, have been measured in the OPAL experiment using 2.4 million hadronic Z0 decays recorded at LEP. Z0 -> b bbar decays were tagged using displaced...

Search for Baryon and Lepton Number Violating $Z^0$ Decays (1999)

Abbiendi, G, Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, ...

Using data collected with the OPAL detector at LEP, we have searched for the processes e+e- -> Z0 -> p e-, p mu- and the charge conjugate final-states. These would violate the conservation of the...

A Measurement of the Product Branching Ratio $f(b \to \Lambda_{b}).BR (\Lambda_{b} \to \Lambda X)$ in $Z^{0}$ Decays (1998)

Abbiendi, G, Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, ...

The product branching ratio, f(b->Lambda_b).BR(Lambda_b->Lambda X), where Lambda_b denotes any weakly-decaying b-baryon, has been measured using the OPAL detector at LEP. Lambda_b are selected by the...

A measurement of the $\tau^{-} \to e^{-} \overline{\nu}_{e}\nu_{\tau}$ branching ratio (1998)

Abbiendi, G, Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, ...

The branching ratio for the decay tau->e nue nutau has been measured using Z0 decay data collected by the OPAL experiment at LEP. In total 33073 tau->e nue nutau candidates were identified from a...

$W^{+}W^{-}$ production and triple gauge boson couplings at LEP energies up to 183 GeV (1998)

Abbiendi, G, Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, ...

A study of W-pair production in e+e- annihilations at Lep2 is presented, based on 877 W+W- candidates corresponding to an integrated luminosity of 57 pb-1 at sqrt(s) = 183 GeV. Assuming that the...

Search for Higgs Bosons in $e^{+} e^{-}$ Collisions at 183 GeV (1998)

Abbiendi, G, Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, ...

The data collected by the OPAL experiment at sqrts=183 GeV were used to search for Higgs bosons which are predicted by the Standard Model and various extensions, such as general models with two Higgs...

Bose-Einstein Correlations in $e^{+} e^{-} \to W^{+}W^{-}$ at 172 and 183 GeV (1998)

Abbiendi, G, Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, ...

Bose-Einstein correlations between like-charge pions are studied in hadronic final states produced by e+e- annihilations at center-of-mass energies of 172 and 183 GeV. Three event samples are...

A Measurement of $R_{b}$ using a Double Tagging Method (1998)

Abbiendi, G, Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, ...

The fraction of Z to bbbar events in hadronic Z decays has been measured by the OPAL experiment using the data collected at LEP between 1992 and 1995. The Z to bbbar decays were tagged using...

Search for Anomalous Photonic Events with Missing Energy in $e^{+} e^{-}$ Collisions at $\sqrt{s}$ = 130, 136 and 183 GeV (1998)

Abbiendi, G, Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, ...

Photonic events with large missing energy have been observed in e+e- collisions at centre-of-mass energies of 130, 136 and 183 GeV collected in 1997 using the OPAL detector at LEP. Results are...

Measurement of the Semileptonic Branching Ratio of Charm Hadrons Produced in $Z^{0} \to c\bar{c}$ Decays (1998)

Abbiendi, G, Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, ...

The inclusive charm hadron semileptonic branching fractions B(c to e) and B(c to mu) in Z to ccbar events have been determined using 4.4 million hadronic Z decays collected with the OPAL detector at...

Search for Chargino and Neutralino Production at $\sqrt{s}$ = 181-184 GeV at LEP (1998)

Abbiendi, G, Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, ...

A search for charginos and neutralinos, predicted by supersymmetric theories, has been performed using a data sample of 57 pb-1 at centre-of-mass energies of 181-184 GeV taken with the OPAL detector...

Measurement of the longitudinal cross-section using the direction of the thrust axis in hadronic events at LEP (1998)

Abbiendi, G, Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, ...

In the process e+e- to hadrons, one of the effects of gluon emission is to modify the 1+cos(theta)**2 form of the angular distribution of the thrust axis, an effect which may be quantified by the...

Search for Acoplanar Lepton Pair Events in $e^{+}e^{-}$ Collisions at $\sqrt{s}$ = 161, 172 and 183 GeV (1998)

Abbiendi, G, Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, ...

A selection of di-lepton events with significant missing transverse momentum has been performed using a total data sample of 77.0 pb-1 at e+e- centre-of-mass energies of 161 GeV, 172 GeV and 183 GeV....

A Study of Parton Fragmentation in Hadronic $Z^{0}$ Decays Using $\Lambda \overline\Lambda$ Correlations (1998)

Abbiendi, G, Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, ...

The correlated production of Lambda and Lambdabar baryons has been studied using 4.3 million multihadronic Zo decays recorded with the OPAL detector at LEP. Di-lambda pairs were investigated in the...

First measurement of $Z/\gamma^{*}$ production in Compton scattering of quasi-real photons (1998)

Abbiendi, G, Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, ...

We report the first observation of Z/gamma* production in Compton scattering of quasi-real photons. This is a subprocess of the reaction e+e- to e+e-Z/gamma*, where one of the final state electrons...

Di-Jet Production in Photon-Photon Collisions at $\sqrt{s}_{ee}$ = 161 and 172 GeV (1998)

Abbiendi, G, Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, ...

Di-jet production is studied in collisions of quasi-real photons radiated by the LEP beams at e+e- centre-of-mass energies 161 and 172 GeV. The jets are reconstructed using a cone jet finding...

Tests of the Standard Model and constraints on new physics from measurements of fermion-pair production at 183 GeV at LEP (1998)

Abbiendi, G, Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, ...

Cross-sections for hadronic, b-bbar and lepton pair final states in e+e- collisions at sqrt(s) = 183 GeV, measured with the OPAL detector at LEP, are presented and compared with the predictions of...

Measurement of the Strong Coupling Constant $\alpha_s$ and the Vector and Axial-Vector Spectral Functions in Hadronic Tau Decays (1998)

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

The spectral functions of the vector current and the axial-vector current have been measured in hadronic tau decays using the OPAL detector at LEP. Within the framework of the Operator Product...

Measurement of the Michel Parameters in Leptonic Tau Decays (1998)

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

The Michel parameters of the leptonic tau decays are measured using the OPAL detector at LEP. The Michel parameters are extracted from the energy spectra of the charged decay leptons and from their...

Search for Higgs bosons and new particles decaying into two photons at $\sqrt{s}$ = 183 GeV (1998)

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 data sample of 57.7 pb-1 collected at an average center-of-mass...

Multi-photon production in $e^{+}e^{-}$ collisions at $\sqrt{s}$= 183 GeV (1998)

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

The process e+e- to gamma gamma (gamma) is studied using data recorded with the OPAL detector at LEP. The data sample corresponds to a total integrated luminosity of 56.2 pb-1 taken at a...

Inclusive production of charged hadrons and $K_{s}^{0}$ mesons in photon-photon collisions (1998)

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

The production of charged hadrons and K_s mesons in the collisions of quasi-real photons has been measured using the OPAL detector at LEP. The data were taken at e+e- centre-of-mass energies of 161...

Measurement of the average polarization of b baryons in hadronic $Z^0$ decays (1998)

Abbiendi, G, Ackerstaff, K, Alexander, Gideon, Allison, J, Altekamp, N, Anderson, K J, ...

In the Standard Model, b quarks produced in e^+e^- annihilation at the Z^0 peak have a large average longitudinal polarization of -0.94. Some fraction of this polarization is expected to be...

Measurement of Tau Branching Ratios to Five Charged Hadrons (1998)

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

The branching ratios of the decay of the tau lepton to five charged hadrons have been measured with the OPAL detector at LEP using data collected between 1991 and 1995 at e+e- centre-of-mass energies...

Measurements of flavour dependent fragmentation functions in $Z^{0} \to q\overline{q}$ events (1998)

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

Fragmentation functions for charged particles in Z -> qq(bar) events have been measured for bottom (b), charm (c) and light (uds) quarks as well as for all flavours together. The results are based on...

Bose-Einstein correlations of three charged pions in hadronic $Z^{0}$ decays (1998)

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

Bose-Einstein Correlations (BEC) of three identical charged pions were studied in 4 x 10^6 hadronic Z^0 decays recorded with the OPAL detector at LEP. The genuine three-pion correlations, corrected...

An upper limit for the $\tau$-neutrino mass from $\tau \to 5\pi^{\pm} \nu_{\tau}$ decays (1998)

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

An upper limit for the tau-neutrino mass has been determined from the decay tau -> 5pi+- \nu_tau using data collected with the OPAL detector from 1991 to 1995 in e+e- collisions at \sqrt{s} ~ M_Z. A...

Photon and light meson production in hadronic $Z^{0}$ decays (1998)

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

The inclusive production rates and differential cross-sections of photons and mesons with a final state containing photons have been measured with the OPAL detector at LEP. The light mesons covered...

Production of $K^{0}_{S}$ and $\Lambda$ in Quark and Gluon Jets from $Z^{0}$ Decay (1998)

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

The production of K^0_S mesons and Lambda baryons in quark and gluon jets has been investigated using two complementary techniques. In the first approach, which provides high statistical accuracy,...

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...

Measurement of triple gauge boson couplings from $W^+ W^-$ production at $\sqrt{s}$ = 172 GeV (1997)

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

We present measurements of triple gauge boson coupling parameters using data recorded by the OPAL detector at LEP2 at a centre-of-mass energy of 172 GeV. A total of 120 W-pair candidates has been...

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...

Measurement of the photon structure function $F_{2}^{\gamma}$ at low x (1997)

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

Deep inelastic electron-photon scattering is studied using e+e- data collected by the OPAL detector at centre-of-mass energies sqrt{s_ee} ~ M_{Z^0}. The photon structure function F_2^gamma(x,Q^2) is...

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...

Measurement of the branching fractions and forward-backward asymmetries of the $Z^0$ into light quarks (1997)

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

Using approximately 4.3 million hadronic Z^0 decays collected with the OPAL detector at LEP between 1990 and 1995, we measure the branching fractions of the Z^0 into up-type and down-type light...

An updated study of B meson oscillations using dilepton events (1997)

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

This paper reports a study of B meson oscillations using hadronic Z^0 decays with two identified leptons, and updates a previous publication by including data collected in 1994. Decay times are...

An upper limit on the branching ratio for $\tau$ decays into seven charged particles (1997)

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

We have searched for decays of the tau lepton into seven or more charged particles, using data collected with the OPAL detector from 1990 to 1995 in e^+e^- collisions at sqrt(s) ~ M_Z. No candidate...

A study of B meson oscillations using hadronic $Z^0$ decays containing leptons (1997)

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

An event sample enriched in semileptonic decays of b hadrons is selected using an inclusive lepton selection from approximately 3.0 million hadronic Z^0 decays collected with the OPAL detector. This...