Measurement of Abb̄FB in hadronic Z decays using a jet charge technique

The bb̄ forward-backward asymmetry has been determined from the average charge flow measured in a sample of 3,500,000 hadronic Z decays collected with the DELPHI detector in 1992 - 1995. The measurement is performed in an enriched bb̄ sample selected using an impact parameter tag and results in the following values for the bb̄ forward-backward asymmetry: Abb̄FB (89.55 GeV) = 0.068 ± 0.018 (stat.) ± 0.0013(syst.) Abb̄FB (91.26 GeV) = 0.0982 ± 0.0047(stat.) ± 0.0016(syst.) Abb̄FB (92.94 GeV) = 0.123 ± 0.016 (stat.) ± 0.0027(syst.) The bb̄ charge separation required for this analysis is directly measured in the b tagged sample, while the other charge separations are obtained from a fragmentation model precisely calibrated to data. The effective weak mixing angle is deduced from the measurement to be: sin2θ1eff = 0.23186 ± 0.00083.0SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Measurement of A(FB)(b(b)over-bar) in hadronic Z decays using a jet charge technique

The bb̄ forward-backward asymmetry has been determined from the average charge flow measured in a sample of 3,500,000 hadronic Z decays collected with the DELPHI detector in 1992 - 1995. The measurement is performed in an enriched bb̄ sample selected using an impact parameter tag and results in the following values for the bb̄ forward-backward asymmetry: Abb̄FB (89.55 GeV) = 0.068 ± 0.018 (stat.) ± 0.0013(syst.) Abb̄FB (91.26 GeV) = 0.0982 ± 0.0047(stat.) ± 0.0016(syst.) Abb̄FB (92.94 GeV) = 0.123 ± 0.016 (stat.) ± 0.0027(syst.) The bb̄ charge separation required for this analysis is directly measured in the b tagged sample, while the other charge separations are obtained from a fragmentation model precisely calibrated to data. The effective weak mixing angle is deduced from the measurement to be: sin2θ1eff = 0.23186 ± 0.00083

Search for charginos, neutralinos and gravitinos in e+e- interactions at √s = 183 GeV

An update of the searches for charginos and neutralinos is presented, based on a data sample corresponding to the 53.9 pb-1 recorded by the DELPHI detector in 1997, at a centre-of-mass energy of 183 GeV. No evidence for a signal was found. The lower mass limits are 4-5 GeV/c2 higher than those obtained at a centre-of-mass energy of 172 GeV. The (μ,M2) domain excluded by combining the neutralino and chargino searches implies a limit on the mass of the lightest neutralino which, for a heavy sneutrino, is constrained to be above 29.1 GeV/c2 for tan β ≥ 1. © 1999 Elsevier Science B.V. All rights reserved.0SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Measurement of A(FB)(b(b)over-bar) in hadronic Z decays using a jet charge technique

The bb̄ forward-backward asymmetry has been determined from the average charge flow measured in a sample of 3,500,000 hadronic Z decays collected with the DELPHI detector in 1992 - 1995. The measurement is performed in an enriched bb̄ sample selected using an impact parameter tag and results in the following values for the bb̄ forward-backward asymmetry: Abb̄FB (89.55 GeV) = 0.068 ± 0.018 (stat.) ± 0.0013(syst.) Abb̄FB (91.26 GeV) = 0.0982 ± 0.0047(stat.) ± 0.0016(syst.) Abb̄FB (92.94 GeV) = 0.123 ± 0.016 (stat.) ± 0.0027(syst.) The bb̄ charge separation required for this analysis is directly measured in the b tagged sample, while the other charge separations are obtained from a fragmentation model precisely calibrated to data. The effective weak mixing angle is deduced from the measurement to be: sin2θ1eff = 0.23186 ± 0.00083

Search for leptoquarks and FCNC in e+e- annihilations at √s = 183 GeV

A search for events with one jet and at most one isolated lepton used data taken at LEP-2 by the DELPHI detector. These data were accumulated at a center-of-mass energy of 183 GeV and correspond to an integrated luminosity of 47.7 pb-1. Production of single scalar and vector leptoquarks was searched for. Limits at 95% confidence leva were derived on the masses (ranging from 134 GeV/c2 to 171 GeV/c2 for electromagnetic type couplings) and couplings of the leptoquark states. A search for top-charm flavour changing neutral currents (e+e-→t̄c or charge conjugate) used the semileptonic decay channel. A limit on the flavour changing cross-section via neutral currents was set at 0.55pb (95% confidence level). © 1999 Elsevier Science B.V. All rights reserved.0SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Measurement of A(FB)(b anti-b) in hadronic Z decays using a jet charge technique

The \BB forward-backward asymmetry %, \AFBbb, has been determined from the average charge flow %, $\langle Q_{FB}\rangle$, measured in a sample of 3,500,000 hadronic Z decays collected with the DELPHI detector in 1992 - 1995. The measurement is performed in an enriched \BB sample selected using an impact parameter tag and results in the following values for the \BB forward-backward asymmetry: \begin {center} \begin{tabular}{ccl} \AFBbb (89.55 GeV) & = & 0.068\,\ \pm0.018\,\ (\mbox{stat.})\pm0.0013 (\mbox{syst.}) \\ \AFBbb (91.26 GeV) & = & 0.0982\pm0.0047(\mbox{stat.})\pm0.0016(\mbox{syst.}) \\ \AFBbb (92.94 GeV) & = & 0.123\,\ \pm0.016\,\ (\mbox{stat.})\pm0.0027(\mbox{ syst.}) \\ \end{tabular} \end{center} %at an average center of mass energy of 91.251\, GeV . % The \BB charge separation %, \db, required for this analysis is directly measured in the b tagged sample, while the other charge separations %, \ddusc, are obtained from a fragmentation model precisely calibrated to data. % The effective weak mixing angle %, \sweff, is deduced from the measurement to be: \begin {center} \begin{tabular}{ccl} \sweff & =& $0.23186\pm0.00083$ \end{tabular} \end{center

Search for charginos, neutralinos and gravitinos in e+ e- interactions at S**(1/2) = 183-GeV

An update of the searches for charginos and neutralinos is presented, basedon a data sample corresponding to the 53.9 pb$^{-1}$ recorded by the DELPHIdetector in 1997, at a centre-of-mass energy of 183 GeV. No evidence for asignal was found. The lower mass limits are 4-5 GeV/$c^2$ higher than thoseobtained at a centre-of-mass energy of 172 GeV.The ($\mu$,M$_2$) domain excludedby combining the neutralino and chargino searches implies a limit on the mass ofthe lightest neutralino which, for a heavy sneutrino, is constrained to beabove 29.1 GeV/$c^2$ for $\tan{\beta}\geq$ 1