Final NOMAD results on νμ→ντ and νe→ντ oscillations including a new search for ντ appearance using hadronic τ decays

Astier, P.; Autiero, D.; Baldisseri, A.; Baldo‐Ceolin, M.; Banner, M.; Bassompierre, G.; Benslama, K.; Besson, N.; Bird, I.; Blumenfeld, B.; Bobisut, F.; Bouchez, J.; Boyd, S.; Bueno, A.; Bunyatov, S.A.; Camilleri, L.; Cardini, A.; Cattaneo, P. W.; Cavasinni, V.; Cervera-Villanueva, A.; Chukanov, A.; Collazuol, G.; Conforto, G.; Conta, C.; Contalbrigo, M.; Cousins, R.; Daniels, D.; Degaudenzi, H.; Prete, T. Del; Santo, A. De; Dignan, T.; Lella, L. Di; Silva, E do Couto e; Dumarchez, J.; Ellis, M.; Feldman, G. J.; Ferrari, R.; Ferrère, D.; Flaminio, V.; Fraternali, M.; Gaillard, J.M.; Gangler, É.; Geiser, A.; Geppert, D.; Gibin, D.; Gninenko, S.; Godley, A.; Gómez-Cadenas, J. J.; Gösset, J.; Gößling, C.; Gouanère, M.; Grant, A.; Graziani, G.; Guglielmi, A.; Hagner, C.; Hernando, J. A.; Hubbard, D.; Hurst, P.; Hyett, Nicole; Iacopini, E.; Joseph, C.; Juget, F.; Kirsanov, M.; Klimov, O.; Kokkonen, J.; Kovzelev, A.; Krasnoperov, A.; Kustov, D.; Кузнецов, В. Е.; Lacaprara, S.; Lachaud, C.; Lakić, B.; Lanza, A.; Rotonda, L. La; Laveder, M.; Letessier‐Selvon, A.; Lévy, J. M.; Linssen, L.; Ljubič, A.; Long, J.; Lupi, A.; Marchionni, A.; Martelli, F.; Méchain, X.; Mendiburu, J. P.; Meyer, J.; Mezzetto, M.; Mishra, S. R.; Moorhead, G. F.; Naumov, D.; Nédélec, P.; Nefedov, Y.; Nguyen-Mau, C.; Orestano, D.; Pastore, F.; Peak, L. S.; Pennacchio, E.; Pessard, H.; Petti, R.; Placci, A.; Polesello, G.; Pollmann, D.; Polyarush, A. Yu.; Popov, Б.; Poulsen, C.; Rico, J.; Riemann, P.; Roda, C.; Rubbia, A.; Salvatore, F.; Schahmanèche, K.; Schmidt, B.; Schmidt, T.; Sconza, A.; Sevior, M. E.; Sillou, D.; Soler, F. J. P.; Sozzi, G.; Steele, D.; Stiegler, U.; Stipč, M; Stolarczyk, Th.; Tareb-Reyes, M.; Taylor, G. N.; Терещенко, В.; Toropin, A.; Touchard, A. M.; Tovey, S. N.; Trân, M. T.; Tsesmelis, E.; Ulrichs, J.; Vacavant, L.; Valdata‐Nappi, M.; Valuev, V.; Vannucci, F.; Varvell, K. E.; Veltri, M.; Vercesi, V.; Vidal–Sitjes, G.; Vieira, J.-M.; Vinogradova, T.; Weber, F. V.; Weisse, Thomas; Wilson, F. F.; Winton, L.J.; Yabsley, B.; Zaccone, H.; Zuber, Κ.; Zuccon, P.

doi:10.1016/s0550-3213(01)00339-x

Cited by 140 publications

(115 citation statements)

References 35 publications

Supporting

Mentioning

114

Contrasting

Order By: Relevance

“…(5.6)-(5.7). as KARMEN [60] and NOMAD [61] ) also sets constraints on the mixing elements [23]. Stronger constraints follow nevertheless in that region, mainly from "peak" and "decay" search experiments.…”

Section: Minimum Seesaw Scales That Future Experiments Could Probementioning

confidence: 99%

Muon conversion to electron in nuclei in type-I seesaw models

Alonso

Dhen

Gavela

et al. 2013

J. High Energ. Phys.

171

175

View full text Add to dashboard Cite

We compute the µ → e conversion in the type-I seesaw model, as a function of the right-handed neutrino mixings and masses. The results are compared with previous computations in the literature. We determine the definite predictions resulting for the ratios between the µ → e conversion rate for a given nucleus and the rate of two other processes which also involve a µ − e flavour transition: µ → eγ and µ → eee. For a quasi-degenerate mass spectrum of right-handed neutrino masses -which is the most natural scenario leading to observable rates-those ratios depend only on the seesaw mass scale, offering a quite interesting testing ground. In the case of sterile neutrinos heavier than the electroweak scale, these ratios vanish typically for a mass scale of order a few TeV. Furthermore, the analysis performed here is also valid down to very light masses. It turns out that planned µ → e conversion experiments would be sensitive to masses as low as 2 MeV. Taking into account other experimental constraints, we show that future µ → e conversion experiments will be fully relevant to detect or constrain sterile neutrino scenarios in the 2 GeV−1000 TeV mass range.

show abstract

Section: Minimum Seesaw Scales That Future Experiments Could Probementioning

confidence: 99%

Muon conversion to electron in nuclei in type-I seesaw models

Alonso

Dhen

Gavela

et al. 2013

J. High Energ. Phys.

171

175

View full text Add to dashboard Cite

show abstract

“…OPERA 90% CL exclusion limits in the ∆m 2 41 vs sin 2 2θ µτ parameter space for the normal (NH, dashed red) and inverted (IH, solid blue) hierarchy of the three standard neutrino masses. The exclusion plots by NOMAD [14] and CHORUS [15] are also shown. Bands are drawn to indicate the excluded regions.…”

Section: % CLmentioning

confidence: 99%

“…The most stringent limits on ν µ → ν τ oscillations were set by the NOMAD [14] and CHORUS [15] experiments, with high sensitivity for ∆m 2 values larger than 10 eV 2 .…”

Section: Introductionmentioning

confidence: 99%

Limits on muon-neutrino to tau-neutrino oscillations induced by a sterile neutrino state obtained by OPERA at the CNGS beam

Agafonova¹,

Aleksandrov²,

Anokhina³

et al. 2015

J. High Energ. Phys.

View full text Add to dashboard Cite

Limits on muon-neutrino to tau-neutrino oscillations induced by a sterile neutrino state obtained by OPERA at the CNGS beamThe OPERA collaboration E-mail: alessandro.paoloni@lnf.infn.it, alessandra.pastore@ba.infn.it Abstract: The OPERA experiment, exposed to the CERN to Gran Sasso ν µ beam, collected data from 2008 to 2012. Four oscillated ν τ Charged Current interaction candidates have been detected in appearance mode, which are consistent with ν µ → ν τ oscillations at the atmospheric ∆m 2 within the "standard" three-neutrino framework. In this paper, the OPERA ν τ appearance results are used to derive limits on the mixing parameters of a massive sterile neutrino. The OPERA collaboration 11 IntroductionThe OPERA experiment [1] operated in the CERN Neutrinos to Gran Sasso (CNGS) beam produced at CERN and directed towards the Gran Sasso Underground Laboratory of INFN (LNGS), 730 km away, where the detector is located. The experiment is unique in its capability to observe ν τ appearance on an event-by-event basis. Nuclear emulsion films instrumenting the target allow the detection of the short-lived τ lepton decay, and hence the identification of ν τ Charged Current (CC) interactions. The standard three-neutrino oscillation framework predicts ν µ → ν τ oscillations with close-to-maximal mixing at the so-called atmospheric scale, ∆m 2 32 ∼ 2.4 × 10 −3 eV 2 [2], i.e. in the oscillation parameters region discovered by detecting atmospheric neutrinos [3]. OPERA has observed four ν τ CC interaction candidate events [4][5][6][7], consistent with the expectation of the standard oscillation framework at this scale. This result represents the first direct evidence of ν µ → ν τ oscillation in appearance mode.In the present paper, limits are derived on the existence of a massive sterile neutrino. The excess of ν e (ν e ) observed by the LSND [8] and MiniBooNE [9] collaborations and the so-called reactor [10] and Gallium [11,12] neutrino anomalies are also interpreted as due to the existence of a fourth sterile neutrino with mass at the eV scale. In relation to this issue, it is worth mentioning that the effective number of neutrino-like species decoupled from the primeval plasma measured by the Planck collaboration is 3.15 ± 0.23 at 95% Confidence Level (CL) [13].Neutrino oscillations at large ∆m 2 have been searched for by several short baseline experiments. The most stringent limits on ν µ → ν τ oscillations were set by the NOMAD [14] and CHORUS [15] experiments, with high sensitivity for ∆m 2 values larger than 10 eV 2 .In the following, a short description of the OPERA experimental setup and of the procedure used to detect ν τ interactions is given, the data analysis is described and exclusion regions in the parameter space are derived.

show abstract

“…exclusion limits in the ∆m 2 41 vs sin 2 2θ µτ parameter space for the normal (NH, red) and inverted (IH, blue) hierarchy of the three standard neutrino masses. The exclusion plots by NOMAD [14] and CHORUS [15] are also shown. Shaded bands are drawn to indicate the excluded regions.…”

Section: Search For Sterile Neutrinosmentioning

confidence: 99%

Results from the OPERA experiment

Crescenzo

2015

Nuclear and Particle Physics Proceedings

View full text Add to dashboard Cite

Abstract. The OPERA neutrino experiment was designed to perform a unique ν τ appearance measurement in the ν µ CNGS beam to confirm the oscillation mechanism in the atmospheric sector ν µ → ν τ . The detection of τ leptons produced in ν τ CC interactions and of their decays is accomplished exploiting the high spatial resolution of nuclear emulsions. Five ν τ candidate events have been detected in the full data sample from 2008-2012 CNGS runs, with an expected background of 0.25 events. The background only hypothesis is rejected with a significance larger than 5 σ. The analysis of the tau neutrino sample in the framework of the 3+1 neutrino model is also presented. Furthermore OPERA good capabilities in detecting electron neutrino interactions allow setting limits on the ν µ → ν e oscillation channel. The OPERA detectorThe aim of the OPERA (Oscillation Project with Emulsion-tRacking Apparatus) experiment [1,2] at the Gran Sasso underground Laboratory (LNGS) was to perform the first direct detection in the appearance mode of ν µ → ν τ oscillations. The direct appearance search was based on the detection of τ leptons produced in charged current interactions (CC) of ν τ . The CERN neutrino beam is an almost pure ν µ beam produced by protons accelerated in the CERN SPS and injected in the CNGS beam line. The OPERA experiment [3,4] was installed in the LNGS Hall C. OPERA was a hybrid apparatus with a modular structure. The detector concept was based on the Emulsion Cloud Chamber (ECC) technique, combined with real-time detection techniques (electronic detectors). The ECC basic unit in OPERA is a brick made of 56 lead plates, providing the required mass, interleaved with 57 nuclear emulsion films, providing the necessary spatial and angular resolution. The electronic detectors were used to trigger the neutrino interactions, to locate the brick in which the interaction took place, to identify muons and measure their momentum and charge. The analysis of nuclear emulsion films is performed in the OPERA scanning laboratories in Europe and Japan by fast automatic scanning systems developed to reconstruct with sub-micrometric accuracy the neutrino interaction events. The detector shown in Fig. 1 is composed of two identical supermodules (SM1 and SM2), each consisting of a target section made of arrays of bricks coupled to a scintillator Target Tracker detector (TT) to trigger the read-out and localize neutrino interactions within the target. Each target section is followed by a muon spectrometer, namely a dipole magnet instrumented with resistive plate chambers a

show abstract

Final NOMAD results on νμ→ντ and νe→ντ oscillations including a new search for ντ appearance using hadronic τ decays

Cited by 140 publications

References 35 publications

Muon conversion to electron in nuclei in type-I seesaw models

Muon conversion to electron in nuclei in type-I seesaw models

Limits on muon-neutrino to tau-neutrino oscillations induced by a sterile neutrino state obtained by OPERA at the CNGS beam

Results from the OPERA experiment

Contact Info

Product

Resources

About