- Neutrino Astro-Physicistedit
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Considering four-neutrino schemes of type 3+1, we identify four small regions of the neutrino mixing parameter space compatible with all data. Assuming a small mixing between the sterile neutrino and the isolated mass eigenstate we show... more
Considering four-neutrino schemes of type 3+1, we identify four small regions of the neutrino mixing parameter space compatible with all data. Assuming a small mixing between the sterile neutrino and the isolated mass eigenstate we show that large νμ → ντ and νe → ντ transitions are predicted in short-baseline experiments and could be observed in the near future in dedicated experiments. We discuss also implications for solar, atmospheric and long-baseline neutrino experiments and we present a formalism that allows to describe in 3+1 schemes atmospheric neutrino oscillations, long-baseline νμ disappearance and νμ → ντ transitions in matter. PACS numbers: 14.60.St Typeset using REVTEX
The theory and phenomenology of light sterile neutrinos at the eV mass scale is reviewed. The reactor, Gallium and LSND anomalies are briefly described and interpreted as indications of the existence of short-baseline oscillations which... more
The theory and phenomenology of light sterile neutrinos at the eV mass scale is reviewed. The reactor, Gallium and LSND anomalies are briefly described and interpreted as indications of the existence of short-baseline oscillations which require the existence of light sterile neutrinos. The global fits of short-baseline oscillation data in 3+1 and 3+2 schemes are discussed, together with the implications for β-decay and neutrinoless double-β decay. The cosmological effects of light sterile neutrinos are briefly reviewed and the implications of existing cosmological data are discussed. The review concludes with a summary of future perspectives. PACS numbers: 14.60.Pq, 14.60.Lm, 14.60.St, 98.80.-k
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We suggest the possibility that the anomalies observed in the LSND experiment and the Gallium radioactive source experiments may be due to neutrino oscillations generated by a large squared-mass difference of about 20–30 eV2. We consider... more
We suggest the possibility that the anomalies observed in the LSND experiment and the Gallium radioactive source experiments may be due to neutrino oscillations generated by a large squared-mass difference of about 20–30 eV2. We consider the simplest 3+1 four-neutrino scheme that can accommodate also the observed solar and atmospheric neutrino oscillations. We show that, in this framework, the disappearance of [Formula: see text] and [Formula: see text] in short-baseline neutrino oscillation experiments is mainly due to active-sterile transitions. The implications of the first MiniBooNE results, appeared after the completion of this paper, are discussed in an addendum.
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... [9] S. Galli, M. Martinelli, A. Melchiorri, L. Pagano, BD Sherwin, DN Spergel, Phys. Rev. D82 (2010) 123504. ... [12] S. Das, TA Marriage, PAR Ade, P. Aguirre, M. Amir, JW Appel, LF Barrientos, ES Battistelli et al., Astrophys. J. 729... more
... [9] S. Galli, M. Martinelli, A. Melchiorri, L. Pagano, BD Sherwin, DN Spergel, Phys. Rev. D82 (2010) 123504. ... [12] S. Das, TA Marriage, PAR Ade, P. Aguirre, M. Amir, JW Appel, LF Barrientos, ES Battistelli et al., Astrophys. J. 729 (2011) 62; JW Fowler et al. ...
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The accurate prediction of the neutrino beam produced in muon decays and the absence of opposite helicity contamination for a particular neutrino flavor make a future neutrino factory the ideal place to look for the lepton flavor... more
The accurate prediction of the neutrino beam produced in muon decays and the absence of opposite helicity contamination for a particular neutrino flavor make a future neutrino factory the ideal place to look for the lepton flavor violating (LFV) decays of the kind µ + → e + ¯ ν e ν µ and lepton number violating (LNV) processes like µ − → e − ν e ν µ. Excellent sensitivities can be achieved using a detector capable of muon and/or electron identification with charge discrimination. This would allow to set experimental limits that improve current ones by more than two orders of magnitude and test the hypothesis that the LSND excess is due to such anomalous decays, rather than neutrino flavor oscillations in vacuum.
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The recent discovery of B-modes in the polarization pattern of the Cosmic Microwave Background by the BICEP2 experiment has important implications for neutrino physics. We revisit cosmological bounds on light sterile neutrinos and show... more
The recent discovery of B-modes in the polarization pattern of the Cosmic Microwave Background by the BICEP2 experiment has important implications for neutrino physics. We revisit cosmological bounds on light sterile neutrinos and show that they are compatible with all current cosmological data provided that the mass is relatively low. Using CMB data, including BICEP-2, we find an upper bound of m s < 0.85 eV (2σ Confidence Level). This bound is strengthened to 0.48 eV when HST measurements of H 0 are included. However, the inclusion of SZ cluster data from the Planck mission and weak gravi-tational measurements from the CFHTLenS project favours a non-zero sterile neutrino mass of 0.44 +0.11 −0.16 eV. Short baseline neutrino oscillations, on the other hand, indicate a new mass state around 1.2 eV. This mass is highly incompatible with cosmological data if the sterile neutrino is fully thermalised (∆χ 2 > 10). However, if the sterile neutrino only partly thermalises it can be compatible with all current data, both cosmological and terrestrial.
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We present a complete update of the analysis of e and " e disappearance experiments in terms of neutrino oscillations in the framework of 3 þ 1 neutrino mixing, taking into account the Gallium anomaly, the reactor anomaly, solar neutrino... more
We present a complete update of the analysis of e and " e disappearance experiments in terms of neutrino oscillations in the framework of 3 þ 1 neutrino mixing, taking into account the Gallium anomaly, the reactor anomaly, solar neutrino data, and e C scattering data. We discuss the implications of a recent 71 Gað 3 He; 3 HÞ 71 Ge measurement which give information on the neutrino cross section in Gallium experiments. We discuss the solar bound on active-sterile mixing and present our numerical results. We discuss the connection between the results of the fit of neutrino oscillation data and the heavy neutrino mass effects in-decay experiments (considering new Mainz data) and neutrinoless double-decay experiments (considering the recent EXO results).
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The recent discovery of B-modes in the polarization pattern of the Cosmic Microwave Background by the BICEP2 experiment has important implications for neutrino physics. We revisit cosmological bounds on light sterile neutrinos and show... more
The recent discovery of B-modes in the polarization pattern of the Cosmic Microwave Background by the BICEP2 experiment has important implications for neutrino physics. We revisit cosmological bounds on light sterile neutrinos and show that they are compatible with all current cosmological data provided that the mass is relatively low. Using CMB data, including BICEP-2, we find an upper bound of m s < 0.85 eV (2σ Confidence Level). This bound is strengthened to 0.48 eV when HST measurements of H 0 are included. However, the inclusion of SZ cluster data from the Planck mission and weak gravi-tational measurements from the CFHTLenS project favours a non-zero sterile neutrino mass of 0.44 +0.11 −0.16 eV. Short baseline neutrino oscillations, on the other hand, indicate a new mass state around 1.2 eV. This mass is highly incompatible with cosmological data if the sterile neutrino is fully thermalised (∆χ 2 > 10). However, if the sterile neutrino only partly thermalises it can be compatible with all current data, both cosmological and terrestrial.
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Scintirad is an interdisciplinary research program that studies novel translational radio- pharmaceuticals for cancer diagnosis and therapy. Scintirad employs methods of the Nuclear Medicine applied to small animals and develops new... more
Scintirad is an interdisciplinary research program that studies novel translational radio- pharmaceuticals for cancer diagnosis and therapy. Scintirad employs methods of the Nuclear Medicine applied to small animals and develops new instrumentation for high resolution imaging. The first part of this report describes research programs, results and future plans, While the second part, entitled “Who We are”, offers an overview of the role of involved teams and facilities.
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ABSTRACT ePrint (Misc)
We present the results of a search for nu_mu → nu_e oscillations in the NOMAD experiment at Cern. The experiment looked for the appearance of nu_e in a predominantly nu_mu wide-band neutrino beam at the CERN SPS. No evidence for... more
We present the results of a search for nu_mu → nu_e oscillations in the NOMAD experiment at Cern. The experiment looked for the appearance of nu_e in a predominantly nu_mu wide-band neutrino beam at the CERN SPS. No evidence for oscillations was found. The 90% confidence limits obtained are Delta m^2 < 0.4 eV^2 for maximal mixing and sin^2(2theta) < 1.4 X 10^-3 for large Delta m^2. This result excludes the LSND allowed region of oscillation parameters with Delta m^2 >~ 10 eV^2.
The EUROnu project has studied three possible options for future, high intensity neutrino oscillation facilities in Europe. The first is a Super Beam, in which the neutrinos come from the decay of pions created by bombarding targets with... more
The EUROnu project has studied three possible options for future, high intensity neutrino oscillation facilities in Europe. The first is a Super Beam, in which the neutrinos come from the decay of pions created by bombarding targets with a 4 MW proton beam from the CERN High Power Superconducting Proton Linac. The far detector for this facility is the 500 kt MEMPHYS water Cherenkov, located in the Fr\'ejus tunnel. The second facility is the Neutrino Factory, in which the neutrinos come from the decay of {\mu}+ and {\mu}- beams in a storage ring. The far detector in this case is a 100 kt Magnetised Iron Neutrino Detector at a baseline of 2000 km. The third option is a Beta Beam, in which the neutrinos come from the decay of beta emitting isotopes, in particular 6He and 18Ne, also stored in a ring. The far detector is also the MEMPHYS detector in the Fr\'ejus tunnel. EUROnu has undertaken conceptual designs of these facilities and studied the performance of the detectors. Base...
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With additional data and improved algorithms, we have enhanced the sensitivity of our appearance search for $\numunutau$ oscillations in the NOMAD detector in the CERN-SPS wide-band neutrino beam. The search uses kinematic criteria to... more
With additional data and improved algorithms, we have enhanced the sensitivity of our appearance search for $\numunutau$ oscillations in the NOMAD detector in the CERN-SPS wide-band neutrino beam. The search uses kinematic criteria to identify $\nutau$ charged current interactions followed by decay of the $\tau^-$ to one of several decay modes. Our ``blind'' analyses of deep-inelastic scattering data taken in 1996 and 1997, combined with consistent reanalyses of previously reported 1995 data, yield no oscillation signal. For the two-family oscillation scenario, we present the contour outlining a 90\% C.L. confidence region in the $\sin^22\theta_{\mu \tau} - \Delta m^2$ plane. At large $\Delta m^2$, the confidence region includes $\sin^22\theta_{\mu\tau}\ <\ 1.2\times10^{-3}$ (a limit 3.5 times more stringent than in our previous publication), while at $\sin^22\theta_{\mu \tau}=1$, the confidence region includes $\Delta m^2 < 1.2$ eV$^2$/$c^4$.
Results from the nu_tau appearance search in a neutrino beam using the full NOMAD data sample are reported. A new analysis unifies all the hadronic tau decays, significantly improving the overall sensitivity of the experiment to... more
Results from the nu_tau appearance search in a neutrino beam using the full NOMAD data sample are reported. A new analysis unifies all the hadronic tau decays, significantly improving the overall sensitivity of the experiment to oscillations. The "blind analysis" of all topologies yields no evidence for an oscillation signal. In the two-family oscillation scenario, this sets a 90% C.L. allowed region in the sin^2(2theta)-Delta m^2 plane which includes sin^2(2theta)<3.3 x 10^{-4} at large Delta m^2 and Delta m^2 < 0.7 eV^2/c^4 at sin^2(2theta)=1. The corresponding contour in the nu_e->nu_tau oscillation hypothesis results in sin^2(2theta)<1.5 x 10^{-2} at large Delta m^2 and Delta m^2 < 5.9 eV^2/c^4 at sin^2(2theta)=1. We also derive limits on effective couplings of the tau lepton to nu_mu or nu_e.
This is a summary of the work done by the Working Package 6 (Physics) of the EU project "EUROnu" during the second year of activity of the project.
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ABSTRACT NOMAD is a neutrino oscillation experiment designed to search for ντ appearance in the CERN-SPS wide band νμ beam. Signal detection relies on the identification of ντ charged current interactions using kinematic criteria. The... more
ABSTRACT NOMAD is a neutrino oscillation experiment designed to search for ντ appearance in the CERN-SPS wide band νμ beam. Signal detection relies on the identification of ντ charged current interactions using kinematic criteria. The analysis of the 1995 data sample yields no oscillation signal. Combining all studied τ decay modes, a limit of is obtained for large Δm2 at the 90% confidence level.