The OPERA long-baseline neutrino experiment was exposed to the CNGS νμ beam from 2008 to 2012, collecting 19505 interactions in the target. The evidence for oscillated ντ appearance, based on the ...observation of three ντ candidate events, has been previously reported. A fourth candidate event has been recently found in an extended data sample, corresponding to about 89% of the final statistics. The absence of a signal from νμ → ντ oscillations is currently excluded at 4.2σ. The status of the analysis is described in detail with special emphasis on the procedures applied for the selection of signal candidate events and the assessment of efficiencies and background. The fourth ντ candidate event is presented and the significance of the observation is discussed.
The NESSiE Collaboration has been setup to undertake a conclusive experiment to clarify the
muon-neutrino disappearance
measurements at short baselines in order to put severe constraints to models ...with more than the three-standard neutrinos. To this aim the current FNAL-Booster neutrino beam for a Short-Baseline experiment was carefully evaluated by considering the use of magnetic spectrometers at two sites, near and far ones. The detector locations were studied, together with the achievable performances of two OPERA-like spectrometers. The study was constrained by the availability of existing hardware and a time-schedule compatible with the undergoing project of multi-site Liquid–Argon detectors at FNAL. The settled physics case and the kind of proposed experiment on the Booster neutrino beam would definitively clarify the existing tension between the
ν
μ
disappearance and the
ν
e
appearance/disappearance at the eV mass scale. In the context of neutrino oscillations the measurement of
ν
μ
disappearance is a robust and fast approach to either reject or discover new neutrino states at the eV mass scale. We discuss an experimental program able to extend by more than one order of magnitude (for neutrino disappearance) and by almost one order of magnitude (for antineutrino disappearance) the present range of sensitivity for the mixing angle between standard and sterile neutrinos. These extensions are larger than those achieved in any other proposal presented so far.
We report on the development of an automated scanning system for nuclear emulsions aiming at very precise spatial and angular measurements. An accuracy of
0.06
μ
m
in position was achieved with the ...emulsion films used for the measurement. An accuracy of 0.4
mrad was achieved for tracks penetrating orthogonally the emulsion films while an accuracy of 1
mrad was obtained for tracks inclined by about 300
mrad with respect to the perpendicular direction. This result shows unprecedented position and angular resolutions achieved by automated measurements.
Understanding physical phenomena at the molecular or even atomic level, comprehending exchange processes in the cells, and storing an increasing amount of data in smaller space are all fields of ...research that require technology not on the micrometer but on the nanometer scale. Among these emerging techniques, we will focus on scanning near-field optical microscopy (SNOM). We will explain its principles and its application in research.
Local spectroscopic investigation of liquid–liquid interfaces and their surroundings is experimentally challenging. Highly localized illumination by a near-field optical probe is a possibility, but ...precise positioning of the probe very close to such an interface prior to measurement has been very difficult. Here, we show how this difficulty is overcome with greatly improved instrumentation. Near-field Raman spectroscopy was used to study the water–carbon tetrachloride interface with a spatial resolution of 200
nm. A blue shift of the OH stretching vibration of water was observed when approaching the interface, indicative a weaker H-bond in the vicinity of the apolar CCl
4.
The kinetic behaviour of β-galactosidase from
Kluyveromices marxianus (
Saccharomyces)
lactis, immobilized on different oxides supports, such as alumina, silica, and silicated alumina has been ...studied. We observed a strong dependence of the immobilized enzyme activities on the chemical nature and physical structure of the supports. In particular, when the particle sizes of the supports are increased, the enzymatic activity strongly decreases.
The hydrolysis of lactose, promoted by the mentioned enzyme immobilized on small commercial silica spheres, has been studied in different operative conditions, by changing: feed rate, reagent and products concentration and temperature, while pH has been kept constant (7.0). A depressing effect originated by both the reaction products, has been observed. Therefore, a kinetic model based on the Michaelis–Menten mechanism, in which the depressing effects of both the hydrolysis products (galactose and glucose) are also considered, have been developed and the related parameters determined.
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