The trigger system of the CHORUS experiment

A new apparatus for detection of nu(mu) --> nu(tau) oscillation has been successfully constructed and operated by the CHORUS Collaboration for the CERN-WA95 experiment. The design, implementation and performance of the electronic trigger system is described. A trigger efficiency of 99% was measured for nu(mu) charged-current events and 90% for neutral-current events

Measurement of charm production in antineutrino charged-current interactions

During the years 1994-1997, the emulsion target of the CHORUS detector was exposed to the wide-band neutrino beam of the CERN SPS collecting about 10(6) neutrino interactions. A measurement of (nu) over bar (mu)-induced charm production is performed by using the presence of a 5% (nu) over bar (mu) component in the nu(mu) beam. The measurement takes advantage of the capability to observe the decay topology in the emulsion. The analysis is based on a sample of charged-current interactions with at least one identified muon. About 100 000 were located in the emulsion target and fully reconstructed. By requiring a positive muon charge as determine

Status report on the CHORUS experiment at CERN

The WA95/CHORUS experiment at CERN is a dedicated vμ-vτ oscillation search experiment. Using the wide band neutrino beam of the CERN-SPS accelerator, with an exposure of 2.4 × 1019 protons on the target, this experiment will explore the domain of small mixing angles down to sin22θμτ ≈ 3 × 10-4 for mass differences Δm2 > 1 eV2, more than one order of magnitude better than the current limits. The conceptual design of the CHORUS experiment and data on the detector performances are reported. © 1995.0SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Measurement of fragmentation properties of charmed particle production in charged-current neutrino interactions

During the years 1994-1997, the emulsion target of the CHORUS detector was exposed to the wide-band neutrino beam of the CERN SPS. In total about 100 000 charged-current neutrino interactions were located in the nuclear emulsion target and fully reconstructed. From this sample of events which was based on the data acquired by new automatic scanning systems, 1048 D0 events were selected by a pattern recognition program. They were confirmed as neutral-particle decays through visual inspection. Fragmentation properties of deep-inelastic charm production were measured using these events. Distributions of the D0 momentum, Feynman x (xF), z and tanθout, the transverse angle out of the leptonic plane defined by the muon and the neutrino, are presented. The mean value of z was measured to be 〈z〉=0.63±0.03(stat)±0.01(syst). From fits to the z distribution, values for the Peterson parameter εP=0.108±0.017(stat) ±0.013(syst) and the Collins-Spiller parameter εCS=0.21-0.04+0. 05(stat)±0.04(syst) are found. For the average value of xF we find 〈xF〉=0.38±0.04(stat)±0.03(syst) and for the forward-backward asymmetry A=0.79±0.14(stat)±0.05(syst). The distribution of tanθout was measured with an average value 〈tanθout〉=0.030±0.002. © 2004 Elsevier B.V. All rights reserved.0SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Measurement of D0 production in neutrino charged current interactions

During the years 1994-1997, the emulsion target of the CHORUS detector was exposed to the Wide Band Neutrino Beam from the CERN-SPS. About 170 000 neutrino interactions were successfully located in the emulsion. Improvements in the automatic emulsion scanning systems and application of different criteria allowed the sample of located events to be used for studies of charm production. We present a measurement of the production rate of D 0 mesons based on a sample of 25 693 located v μ charged-current (CC) interactions analysed so far. After reconstruction of the event topology in the vertex region, 283 D 0 decays were observed with an estimated background of 9.2 K 0 and Λ decays. The ratio of cross-section of D 0 production and v μ CC interactions is found to be (1.99 ± 0.13(stat.) ± 0.17(syst.)) × 10 -2 at 27 GeV average v μ energy. © 2002 Elsevier Science B. V. All rights reserved.0SCOPUS: ar.jinfo:eu-repo/semantics/publishe