The trigger system of the NOMAD experiment

Altegoer, J.; Andrle, J.; Boyd, S.; Cardini, A.; Farthouat, P.; Ferrari, R.; Geppert, D.; Gößling, C.; Huta, W.; Hyett, Nicole; Koch, N; Lanza, A.; Long, J.; Moorhead, G. F.; Pollmann, D.; Poulsen, C.; Rubbia, A.; Schmidt, B.; Soler, F. J. P.; Steele, D.; Varvell, K. E.; Weisse, Thomas; Winton, L.J.; Yabsley, B.; Voullieme, A.

doi:10.1016/s0168-9002(99)00176-x

Cited by 20 publications

(18 citation statements)

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“…This cut serves as an HCAL veto and is confirmed by random trigger events and Monte Carlo (MC) studies [13]; • the total energy of the pair must be greater than 4 GeV and its invariant mass m e + e − < 95 MeV to remove background from pairs of particles other than e + e − .…”

Section: Data Analysis and Selection Criteriamentioning

confidence: 90%

Search for heavy neutrinos mixing with tau neutrinos

et al. 2001

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We report on a search for heavy neutrinos (ν 4 ) produced in the decay D s → τ ν 4 at the SPS proton target followed by the decay ν 4 → ν τ e + e − in the NOMAD detector. Both decays are expected to occur if ν 4 is a component of ν τ . From the analysis of the data collected during the 1996-1998 runs with 4.1 × 10 19 protons on target, a single candidate event consistent with background expectations was found. This allows to derive an upper limit on the mixing strength between the heavy neutrino and the tau neutrino in the ν 4 mass range from 10 to 190 MeV. Windows between the SN1987a and Big Bang Nucleosynthesis lower limits and our result are still open for future experimental searches. The results obtained are used to constrain an interpretation of the time anomaly observed in the KARMEN1 detector.Key words: neutrino mixing, neutrino decay IntroductionIn the Standard Model all fundamental fermions have a right-handed component that transforms as an isosinglet under the SU(2) L gauge group except neutrinos, which are observed only in left-handed form. However, heavy neutrinos which are decoupled from W and Z bosons and hence are mostly isosinglet (sterile) arise in many models that attempt to unify the presently known interactions into a single gauge scheme, such as Grand Unified Theories or Superstrings inspired models [1]. They are also predicted in models trying to solve the problem of baryo-or leptogenesis in the Universe, in many extended electroweak models, such as left-right symmetric and see-saw models [1]. Their masses are predicted to be within the GeV − TeV range. The existence of a light ( eV or ≪ eV) sterile neutrino is expected in schemes that attempt to solve the presently observed indication from atmospheric, solar and LSND experiments that neutrinos are massive, see e.g. [2] and references therein. More generally one can also look for an isosinglet neutrino with intermediate mass such as in the keV − MeV range. For instance, such neutrinos with masses in the range 1 -40 keV were recently considered as a candidate for warm dark matter [3].If heavy neutrinos exist, many crucial questions arise. For example, for massive neutrinos the flavour eigenstates (ν e , ν µ , ν τ , ...) need not coincide with the mass eigenstates (ν 1 , ν 2 , ν 3 , ν 4 ...), but would, in general, be related through a unitary transformation. Such a generalised mixing:could result in neutrino oscillations when the mass differences are small, and in decays of heavy neutrinos when the mass differences are large. The motivation and purpose of this work is to search for a neutral heavy lepton ν 4 which is dominantly associated with the third generation of light neutrinos, ν τ , via the mixing term |U τ 4 | 2 . If such a particle exists it might be produced in the decay D s → τ ν 4 at the SPS proton target followed by the decay ν 4 → ν τ e + e − in the NOMAD detector as is illustrated in Figure 1 (see also Section 3). The experimental signature of these events is clean and they can be selected with small background due t...

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Section: Data Analysis and Selection Criteriamentioning

confidence: 90%

Search for heavy neutrinos mixing with tau neutrinos

et al. 2001

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“…A transition radiation detector (TRD) [38,39] placed at the end of the active target was used for particle identification. Two scintillation counter trigger planes [40] were used to trigger on neutrino interactions in the NOMAD active target. A lead-glass electromagnetic calorimeter [41,42] located downstream of the tracking region provided an energy resolution of 3.2%/ √ E[GeV] ⊕ 1% for electromagnetic showers and was crucial to measure the total energy flow in neutrino interactions.…”

Section: The Nomad Detectormentioning

confidence: 99%

A study of quasi-elastic muon neutrino and antineutrino scattering in the NOMAD experiment

Lyubushkin¹,

Popov²,

Kim³

et al. 2009

Eur. Phys. J. C

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We have studied the muon neutrino and antineutrino quasi-elastic (QEL) scattering reactions (ν μ n → μ − p andν μ p → μ + n) using a set of experimental data collected by the NOMAD Collaboration. We have performed measurements of the cross-section of these processes on a nuclear target (mainly carbon) normalizing it to the total ν μ (ν μ ) charged-current cross section. The results for the flux-averaged QEL cross sections in the (anti)neutrino energy interval 3-100 GeV are σ qel ν μ = (0.92 ± 0.02(stat) ± 0.06(syst)) × 10 −38 cm 2 and σ qel ν μ = (0.81 ± 0.05(stat) ± 0.09(syst)) × 10 −38 cm 2 for neutrino and antineutrino, respectively. The axial mass parameter M A was extracted from the measured quasi-elastic neutrino cross section. The corresponding result is M A = 1.05±0.02(stat)±0.06(syst) GeV. It is consistent with the axial mass values recalculated from the antineutrino cross section and extracted from the pure Q 2 shape analysis of the high purity sample of ν μ quasielastic 2-track events, but has smaller systematic error and should be quoted as the main result of this work. Our measured M A is found to be in good agreement with the world average value obtained in previous deuterium filled bubble chamber experiments. The NOMAD measurement of M A is lower than those recently published by K2K and MiniBooNE Collaborations. However, within the large errors quoted by these experiments on M A , these results are compatible with the more precise NOMAD value.PACS 13.15.+g · 25.30.Pt

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“…The TRD yielded a pion rejection factor of 1000 for an electron efficiency of 90% in the momentum range 1 to 50 GeV/c. Two scintillation counter trigger planes [23], T 1 and T 2 , bracketed the TRD.…”

Section: Detectormentioning

confidence: 99%

Prediction of neutrino fluxes in the NOMAD experiment

Astier¹,

Autiero²,

Baldisseri³

et al. 2003

Nuclear Instruments and Methods in Physics Research Section A:

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2The method developed for the calculation of the flux and composition of the West Area Neutrino Beam used by NOMAD in its search for neutrino oscillations is described. The calculation is based on particle production rates computed using a recent version of FLUKA and modified to take into account the cross sections measured by the SPY and NA20 experiments. These particles are propagated through the beam line taking into account the material and magnetic fields they traverse. The neutrinos produced through their decays are tracked to the NOMAD detector. The fluxes of the four neutrino flavours at NOMAD are predicted with an uncertainty of about 8% for ν µ and ν e , 10% forν µ , and 12% forν e . The energy-dependent uncertainty achieved on the ν e /ν µ prediction needed for a ν µ → ν e oscillation search ranges from 4% to 7%, whereas the overall normalization uncertainty on this ratio is 4.2%.

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The trigger system of the NOMAD experiment

Cited by 20 publications

References 20 publications

Search for heavy neutrinos mixing with tau neutrinos

Search for heavy neutrinos mixing with tau neutrinos

A study of quasi-elastic muon neutrino and antineutrino scattering in the NOMAD experiment

Prediction of neutrino fluxes in the NOMAD experiment

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