Data collected with the DELPHI detector from 1993 to 1995 combined with previous DELPHI results for data from 1991 and 1992 yield the branching fractions \(B({\tau \rightarrow \mbox{\rm e} \nu ...\bar{\nu}}) = (17.877 \pm 0.109_{stat} \pm 0.110_{sys} )\% \) and \(B({\tau \rightarrow \mu \nu \bar{\nu}}) = (17.325 \pm 0.095_{stat} \pm 0.077_{sys} )\% \).
Data taken by DELPHI during the 1995 and 1996 LEP runs have been used to search for the supersymmetric partners of electron, muon and tau leptons and of top and bottom quarks. The observations are in ...agreement with standard model predictions. Limits are s
Measurement of the lifetime of b-baryons Abreu et al, P.
The European physical journal. C, Particles and fields,
09/1999, Letnik:
10, Številka:
2
Journal Article
Recenzirano
Odprti dostop
The average lifetime of weakly decaying b-baryons was studied using 3.6 million \(Z^0\) hadronic decays collected by the DELPHI detector at LEP. The measurement of the proper decay time distribution ...of secondary vertices was used on three complementary samples. The first sample consisted of events with a fully reconstructed \(\Lambda_c^+\) and an opposite charge lepton, or an oppositely charged lepton pair accompanied by a \(\Lambda^0\). The other two samples were more inclusive, where b-baryon semileptonic decays were recognized by the presence of either a proton identified by the RICH detector or a \(\Lambda^0\) and a lepton of charge opposite to that of the proton. The combined result was:
A search for charginos with masses close to the mass of the lightest neutralino is reported, based on the data collected with the DELPHI detector at LEP from 1995 to 1997 at centre-of-mass energies ...between 130 and 183 GeV. The signature of a photon at high transverse momentum radiated from the initial state reduces the two-photon background to acceptable rates, thus making the mass differences between a few hundred MeV/c\(^2\) and 3 GeV/c\(^2\) detectable. In very nearly degenerate scenarios, the lifetime of the chargino can be large enough to produce either visible secondary vertices or decays outside the detector; therefore, quasi-stable heavy charged particles and displaced decay vertices were also searched for. No excess of events with respect to the Standard Model expectations was observed, and limits in the plane of chargino-neutralino mass difference versus chargino mass are given.
The cross sections for the production of single charged and neutral intermediate vector bosons were measured using integrated luminosities of 52 pb–1 and 154 pb–1 collected by the experiment at ...centre-of-mass energies of 182.6 GeV and 188.6 GeV, respectively. The cross sections for the reactions were determined in limited kinematic regions. The results found are in agreement with the Standard Model predictions for these channels.
A High Spectral Resolution Lidar (HSRL) is designed in order to achieve high accuracy measuring the aerosol to molecular scattering coefficients ratio. This type of Lidar consists of a Continuous ...Wave Single Longitudinal Mode laser beam at 532 nm, a receiver with a parabolic mirror and analyzes spectrally the scattered light in a Fabry-Perot Cavity. The great wavelength sensitivity of this system allows the separation of the aerosol and molecular component due to their different levels of Doppler effects on the scattered laser light. We present a study of the effects of the various levels of CCD cooling on the sensitivity of this. Firstly we discuss preliminary experimental results based on a Fabry-Perot etalon with free spectral range (FSR)
0.1
cm
−
1
, the expected performance of a etalon with FSR of
0.05
cm
−
1
, under construction, and with finally an aerosol parameter analysis in Simulation Codes for EAS.
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