Walter Van Doninck

Observation of an Excess of electron-neutrino, anti-electron-neutrino Events in a Beam Dump Experiment at 400-GeV

Abstract A beam dump experiment has been performed at CERN in Gargamelle using the neutrino facility to look for penetrating particles produced either directly in the beam interaction or by prompt decay of new particles. A total of 32 interactions with a visible energy greater than 10 GeV has been found, classified, aftercorrections, into 18 charged current ν μ or ν μ , 5.1 neutral current and 8.9 ν e or ν e charged current events. An excess of ν e events remains after all subtractions from any established sources. Results are presented in terms of the product of the cross section and the leptonic decay branching ratio of the possible source.

High-energy Electronic Neutrino (

Abstract The total cross-sections for v e ( v e ) -nucleon scattering have been measured. A test has been made of the muon number conservation law. A limit of 2.4 GeV is found the mass of the “Georgi-Glashow type” heavy lepton

\nu_e

Abstract We have fully analysed all events with a single electron obtained in an exposure of BEBC to the 350 GeV wide-band neutrino beam at CERN. The data agrees well with expectations based on the calculated ν e flux and assuming μ−e universality. Using both the rate and the kinematic distributions, improved limits are set on ν e → ν X , ν μ → ν e , ν μ → ν τ mixing.

) and Anti-neutrino (

Abstract An event with the decay chain Σ c + → Λ c + + π 0 , Λ c + → K − + p + π + , has been observed in an exposure of BEBC, equipped with a track sensitive target, to the wide band neutrino beam from the SPS at CERN. The event has a unique three constraint kinematic fit to the ΔS = − ΔQ reaction v + p → μ − + p + K − + π + + π + + π 0 with both gammas from the π 0 decay detected. The proton and other final state particles are identified. The masses are M ( Λ c + ) = 2290 ± 3 MeV/ c 2 , M ( Σ c + ) = 2457 ± 4 MeV/ c 2 and M ( Σ c + ) − M ( Λ c + ) = 168 ± 3 MeV/ c 2 . Including other data one obtains M ( Σ c ++ ) − M ( Σ c + ) = 0 ± 4 MeV/ c 2 .

\bar{\nu}_e

In the framework of the High Luminosity LHC upgrade program, the CMS muon group built several different RPC prototypes that are now under test at the new CERN Gamma Irradiation Facility (GIF++). A dedicated Detector Control System (DCS) has been developed using the WinCC-OA tool to control and monitor these prototype detectors and to store the measured parameters data. Preliminary efficiency studies that set the base performance measurements of CMS RPC for starting aging studies are also presented.

) Interactions

A new precise measurement of \V-cb\ and of the branching ratio BR([(Bover bar](0)→ D(+*)l(-)[([nu])over bar](l)) has been performed using a sample of about 5000 semileptonic decays (B) over bar (0) → D(*+)l(-)[([nu])over bar](l), selected by the DELPHI detector at LEP 1 by tagging the soft pion from D*+ → D(0)pi (+). The results are: V-cb = (39.0 +/- 1.5 (stat.)(- 2.6)(+2.5) (syst. exp.) +/- 1.3(ayst. th.)) x 10(-3). BR((B) over bar0 → D(*+)l(-)[([nu])over bar](l)) = (4.70 +/- 0.13(stat.)(-0.31)(+0.36) (syst. exp.))%. The analytic dependencies of the differential cross-section and of the Isgur-Wise form factor as functions of the variable w = v(B)0 . v(D)* have also been obtained by unfolding the experimental resolution.

Limits on neutrino oscillations from a study of νe charged current interactions

AbstractThe spectra of prompt electrons and muons from the semi-leptonic decays of heavy hadrons produced inZ0 decays have been used to measure the coupling of theZ0 tob quarks weighted by theB hadrons mean semi-leptonic branching fraction, giving a value:

Detector control system and efficiency performance for CMS RPC at GIF

BR_{sl}^b *{{\Gamma _{b\bar b} } \mathord{\left/ {\vphantom {{\Gamma _{b\bar b} } {\Gamma _H }}} \right. \kern-\nulldelimiterspace} {\Gamma _H }} = 0.0221 \pm 0.0015