CONSTRUCTION AND TEST OF MODULES OF THE CHORUS CALORIMETER

The CHORUS Collaboration is presently building a new detector for the search of nu(mu)-nu(tau) oscillations in the CERN neutrino beam, the experiment being sensitive to a mixing angle an order of magnitude smaller than the present limit. The basic components of the CHORUS ''hybrid'' detector are an active target made of nuclear emulsions, an air core spectrometer with scintillating fiber tracking, a high resolution calorimeter and a muon spectrometer. An account is given here of the design of the 110-tons compensating calorimeter, made of 1 mm diameter scintillating fibers embedded in a lead matrix, and of the test results from the first modules produced

Construction and Test of Modules of the Chorus Calorimeter

The CHORUS Collaboration is presently building a new detector for the search of nu(mu)-nu(tau) oscillations in the CERN neutrino beam, the experiment being sensitive to a mixing angle an order of magnitude smaller than the present limit. The basic components of the CHORUS ''hybrid'' detector are an active target made of nuclear emulsions, an air core spectrometer with scintillating fiber tracking, a high resolution calorimeter and a muon spectrometer. An account is given here of the design of the 110-tons compensating calorimeter, made of 1 mm diameter scintillating fibers embedded in a lead matrix, and of the test results from the first modules produced

Response to electrons and pions of the calorimeter for the CHORUS experiment

We built and tested on charged particle beams the high energy-resolution calorimeter for the CHORUS experiment, which searches for nu(mu)-nu(tau) oscillations in the CERN Wide Band Neutrino Beam. This calorimeter is longitudinally divided into three sectors: one electromagnetic and two hadronic. The first two upstream sectors are made of lead and plastic scintillating fibers in the volume ratio of 4/1, and they represent the first large scale application of this technique for combined electromagnetic and hadronic calorimetry. The third sector is made of a sandwich of lead plates and scintillator strips and complements the measurement of the hadronic energy flow. In this paper, we briefly describe the calorimeter design and we show results on its response to electrons and pions, obtained from tests performed at the CERN SPS and PS. An energy resolution of sigma(E)/E=(32.3+/-2.4)%/root E(GeV)+(1.4+/-0.7)% was achieved for pions, and sigma(E)/E=(13.8+/-0.9)%/root V(GeV)+(-0.2+/-0.4)% for electrons

CONSTRUCTION AND TEST OF CALORIMETER MODULES FOR THE CHORUS EXPERIMENT

The construction of modules and the assembly of the calorimeter for CHORUS, an experiment that searches for nu(mu) nu(tau) oscillation, have been completed. Within the experiment, the calorimeter is required to measure the energy of hadronic showers produced in neutrino interactions with a resolution of similar to 30%/root E(GeV). To achieve this performance, the technique, developed in recent years, of embedding scintillating fibers of 1 mm diameter into a lead matrix has been adopted for the most upstream part of the calorimeter. A more conventional system, of alternating layers of lead and scintillator strips, was used for the rest. Details of module construction as well as results obtained when modules were exposed to electron and muon beams are presented

Performance of the CHORUS lead-scintillating fiber calorimeter

We report on the design and performance of the lead-scintillating fiber calorimeter of the CHORUS experiment, which searches for νμ-ντ oscillations in the CERN Wide Band Neutrino beam. Two of the three sectors in which the calorimeter is divided are made of lead and plastic scintillating fibers, and they represent the first large scale application of this technique for combined electromagnetic and hadronic calorimetry. The third sector is built using the sandwich technique with lead plates and scintillator strips and acts as a tail catcher for the hadronic energy flow. From tests performed at the CERN SPS and PS an energy resolution of σ(E)/E=(32.3±2.4)%/E(GeV)+(1.4±0.7)% was measured for pions, and σ(E)/E=(13.8±0.9)%/E(GeV)+(−0.2±0.4)% for electrons

FLAVOR UNIVERSALITY OF NEUTRINO COUPLINGS WITH THE Z

We are reporting the first experimental result of the coupling of the muon neutrino with the Z. This result is in good agreement with the average value of the coupling of the three neutrino families as derived from the invisible decay width of the Z. We also determined g(v tau) assuming N-v = 3

CONSTRAINTS ON ADDITIONAL Z-BOSONS DERIVED FROM NEUTRINO-ELECTRON SCATTERING MEASUREMENTS

We report new constraints on the existence of additional Z bosons derived from neutrino-electron scattering data. The analysis is based on data taken by the CHARM II Collaboration during five years of exposure of the detector to the wide band neutrino beam at CERN. The limits on the mass of these new particles are evaluated in the framework of E6 superstring-inspired theories and Left-Right symmetric models. Limits on the so-called Z1 are also reported