P. Loverre

Measurement of charm production in neutrino charged-current interactions

The nuclear emulsion target of the CHORUS detector was exposed to the wide-band neutrino beam of the CERN SPS of 27 GeV average neutrino energy from 1994 to 1997. In total, about 100 000 charged-current (CC) neutrino interactions with at least one identified muon were located in the emulsion target and fully reconstructed, using newly developed automated scanning systems. Charmed particles were searched for by a program recognizing particle decays. The observation of the decay in nuclear emulsion makes it possible to select a sample with very low background and minimal kinematical bias. In all, 2013 CC interactions with a charmed hadron candidate in the final state were selected and confirmed through visual inspection. The charm production rate induced by neutrinos relative to the CC cross-section is measured to be σ(νμN→μ−CX)/σ(CC)=(5.75 ± 0.32(stat)±0.30(syst))%. The charm production cross-section as a function of neutrino energy is also obtained. The results are in good agreement with previous measurements. The charm-quark hadronization produces the following charmed hadrons with relative fractions (in %): fD0=43.7±4.5, fΛc+=19.2±4.2, fD+=25.3±4.2 and fDs+=11.8±4.7.

Search for Charged Current Coherent Pion Production on Carbon in a Few-GeV Neutrino Beam

The SciBooNE Collaboration has performed a search for charged current coherent pion production from muon neutrinos scattering on carbon, nu{sub {mu}}{sup 12}C- {yields} {mu}{sup 12}Cpi{sup +}, with two distinct data samples. No evidence for coherent pion production is observed. We set 90% confidence level upper limits on the cross section ratio of charged current coherent pion production to the total charged current cross section at 0.67 x 10{sup -2} at mean neutrino energy 1.1 GeV and 1.36 x 10{sup -2} at mean neutrino energy 2.2 GeV.

Construction and test of calorimeter modules for the CHORUS experiment

Abstract The construction of modules and the assembly of the calorimeter for CHORUS, an experiment that searches for ν μ ↔ ν τ 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 /∼30%/√ 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.

Measurement of inclusive charged current interactions on carbon in a few-GeV neutrino beam

The SciBooNE Collaboration reports a measurement of inclusive charged current interactions of muon neutrinos on carbon with an average energy of 0.8 GeV using the Fermilab Booster Neutrino Beam. We compare our measurement with two neutrino interaction simulations: NEUT and NUANCE. The charged current interaction rates (product of flux and cross section) are extracted by fitting the muon kinematics, with a precision of 6-15% for the energy dependent and 3% for the energy integrated analyses. We also extract CC inclusive interaction cross sections from the observed rates, with a precision of 10-30% for the energy dependent and 8% for the energy integrated analyses. This is the first measurement of the CC inclusive cross section on carbon around 1 GeV. These results can be used to convert previous SciBooNE cross section ratio measurements to absolute cross section values.

Search for νμ → ντ oscillation

Abstract The fine granularity of the CHARM-II detector has been exploited to search, in the CERN-SPS wide band neutrino beam, for quasi-elastic ντ interactions followed by the decay τ → πντ. Since the sampling thickness of the target calorimeter corresponds to ∼ 1 9 of an interaction length, these events appear in the detector as a single track followed by a hadronic shower. The study of the “single pion” events is used to set limits on the νμ → ντ oscillation parameters. The maximum sensitivity to the mixing angle θ is reached for Δm2 = 50 eV2 allowing to exclude values of sin22θ greater than 6.4 × 10−3 at 90% CL.

Charm D-meson production in 360 GeV/cπ−p interactions; Evidence for leading quarks

Abstract Charm D-meson production in 360 GeV π−p interactions has been studied using the high-resolution hydrogen bubble chamber LEBC and the European Hybrid Spectrometer. The data show evidence for leading quark effects both in the number of D-meson types and in the Feynman x distributions. The production cross section is of the form d 2 δ d x d p T 2 ∞(1-x) n exp (-ap T 2 ) with n = 2.8±0.8 and a = 1.1±0.3 (GeV/c)−2. The x distribution is, however, compatible with the presence of both central (n = 6) and leading (n = 1) D / D production. The fraction of D-messons in the leading component is estimated to be ≈30%. The rapidity gap between members of reconstructed charm pairs is small compared to the available rapidity range. The inclusive cross section for single D-messons in the forward direction is: δ(D/ D )=(40 8 +15 )μ b ( for x>0) .

Measurement of Inclusive Neutral Current Neutral

We acknowledge the Physics Department at Chonnam National University, Dongshin University, and Seoul National University for the loan of parts used in SciBar and the help in the assembly of SciBar. We wish to thank the Physics Departments at the University of Rochester and Kansas State University for the loan of Hamamatsu PMTs used in the MRD. We gratefully acknowledge support from Fermilab as well as various grants, contracts and fellowships from the MEXT and JSPS (Japan), the INFN (Italy), the Ministry of Science and Innovation and CSIC (Spain), the STFC (UK), and the DOE and NSF (USA). This work was supported by MEXT and JSPS with the Grant-in-Aid for Scientific Research A 19204026, Young Scientists S 20674004, Young Scientists B 18740145, Scientific Research on Priority Areas “New Developments of Flavor Physics”, and the global COE program “The Next Generation of Physics, Spun from Universality and Emergence”. The project was supported by the Japan/U.S. Cooperation Program in the field of High Energy Physics and by JSPS and NSF under the Japan-U.S. Cooperative Science Program.

\pi^0

We built and tested on charged particle beams the high energy-resolution calorimeter for the CHORUS experiment, which searches for νμ-ντ 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 41, 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 σ(E)/E=(32.3±2.4)%/E(GeV) + (1.4±0.7)% was achieved for pions, and σ(E)/E=(13.8±0.9)%/E(GeV) + (−0.2±0.4)% for electrons.

Production on Carbon in a Few-GeV Neutrino Beam

Abstract The CHARM II Collaboration is building a massive, fine-grained and low-density detector for the study of neutrino-electron scattering. Its target calorimeter consists of 441 detector planes with 155 232 plastic streamer tubes with digital readout of the wires and analog readout of external pickup strips. At the time of this report, about 25% of the calorimeter planes were equipped with electronics. Results on the performance of these tubes are presented as obtained with cosmic-rays and with electron and pion beams. We have also investigated the use of water vapour as an additive to the gas to suppress coating of the anode wires. The use of water would be of particular importance when using the tubes in a high-rate environment.

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

Abstract We are reporting on a new determination of sin2ϑw from the ratio of v μ e to v e scattering cross sections. A new detector designed for this purpose was exposed tothe Wide Band Neutrino Beamof the 450 GeV (CERN SPS. An analysis of data taken in 1987 and 1988 is presented based on 762 vμe and 1017 v e events. From the ratio of σ( v μ e ) to σ( v μ e ) we determined sin2ϑw=0.233±0.012 (stat) ± 0.008 (syst) without radiative correction. With radiative correction for mt=mH=100 GeV we find sin2ϑw=0.232±0.012(stat)±0.008(syst).