Neutrinos are abundantly produced in the LHC. Flavour composition and energy reach of the neutrino flux from proton-proton collisions depend on the pseudorapidity . At large , energies can exceed the ...TeV, with a sizeable contribution of the τ flavour. A dedicated detector could intercept this intense neutrino flux in the forward direction, and measure the interaction cross section on nucleons in the unexplored energy range from a few hundred GeV to a few TeV. The high energies of neutrinos result in a larger N interaction cross section, and the detector size can be relatively small. Machine backgrounds vary rapidly while moving along and away from the beam line. Four locations were considered as hosts for a neutrino detector: the CMS quadrupole region (25 m from CMS Interaction Point (IP)), UJ53 and UJ57 (90 and 120 m from CMS IP), RR53 and RR57 (240 m from CMS IP), TI18 (480 m from ATLAS IP). The potential sites are studied on the basis of (a) expectations for neutrino interaction rates, flavour composition and energy spectrum, (b) predicted backgrounds and in situ measurements, performed with a nuclear emulsion detector and radiation monitors. TI18 emerges as the most favourable location. Already with 150 fb−1 expected in LHC Run3, a small detector in TI18 could measure, for the first time and with good precision, the high-energy N cross section for all neutrino flavours.
Results from the OPERA experiment Crescenzo, A. Di
EPJ Web of Conferences,
01/2017, Letnik:
164
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
The OPERA neutrino experiment was designed to perform a unique vτ appearance measurement in the vμ CNGS beam to confirm the oscillation mechanism in the atmospheric sector vμ → vτ. The detection of ...vτ leptons produced in vτ CC interactions and of their decays is accomplished exploiting the high spatial resolution of nuclear emulsions. Five vτ 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 vμ → ve oscillation channel.
The OPERA experiment observed νμ → ντ oscillations in the atmospheric sector. To this purpose the hybrid OPERA detector was exposed to the CERN Neutrinos to Gran Sasso beam from 2008 to 2012, at a ...distance of 730 km from the neutrino source. Charged-current interactions of ντ were searched for through the identification of τ lepton decay topologies. The five observed ντ interactions are consistent with the expected number of events in the standard three neutrino framework. Based on this result, new limits on the mixing parameters of a massive sterile neutrino may be set. Preliminary results of the analysis performed in the 3+1 neutrino framework are here presented.
This paper relates to the upgrading of model biogas mixtures, typically 60/40 CH4/CO2, by clathrate (gas) hydrates, which have recently been considered as a safe alternative to high-pressure or ...liquefied gas storage, and as an economic, chemical-free process for the separation of gas mixtures. Several factors affecting the driving force to hydrate formation are considered, such as the degree of overpressurization and the presence of chemical promoters. Promoters used were several anionic and zwitterionic surfactants which are demonstrated to affect the hydrate-forming ability of water. Some lignin derivatives were also tested. Promoted hydrates were also compared to hydrate-based separation starting from nonpromoted water. Separation experiments were conducted under pressures of 4 and 2.5 MPa at 274 K, under either pressure-dropping or constant pressure conditions. Results show that the separation ability of clathrate hydrates as determined by the separation factor S is highest when no promoters are added to the water phase; the well-known promoter sodium dodecyl sulfate (SDS) shows a value of S which is approximately half the value of that in pure water while higher separations were obtained with some lignin derivatives and a non-surface-active naphthalenesulfonate derivative. We also show that the contribution of CO2 solubility in water to S is a main player in the overall process. Finally, the separation ability of hydrates seems to be inversely proportional to the amount of gas mixture enclathrated, i.e., the occupancy.
Three functional measures of the shape of univariate distributions are proposed which are consistent with respect to the convex transform order. The first two are weighted tail indices that ...characterize location-scale families of distributions, whilst the third is a skewness measure. Properties of the new measures are established for various classes of symmetric and asymmetric distributions, and the generalized Pareto distribution characterized in terms of them. Kernel density based estimation of the measures is also considered, and the use of the estimated functionals is illustrated in the analysis of two real data sets.
A
bstract
Heavy Neutral Leptons (HNLs) are hypothetical particles predicted by many extensions of the Standard Model. These particles can, among other things, explain the origin of neutrino masses, ...generate the observed matter-antimatter asymmetry in the Universe and provide a dark matter candidate.
The SHiP experiment will be able to search for HNLs produced in decays of heavy mesons and travelling distances ranging between
O
(50 m) and tens of kilometers before decaying. We present the sensitivity of the SHiP experiment to a number of HNL’s benchmark models and provide a way to calculate the SHiP’s sensitivity to HNLs for arbitrary patterns of flavour mixings. The corresponding tools and data files are also made publicly available.
Abstract
Nuclear emulsion is a well-known detector type proposed also for the directional detection of dark matter. In this paper, we study one of the most important properties of direction-sensitive ...detectors: the preservation by nuclear recoils of the direction of impinging dark matter particles. For nuclear emulsion detectors, it is the first detailed study where a realistic nuclear recoil energy distribution with all possible recoil atom types is exploited. Moreover, for the first time we study the granularity effect on the emulsion detector directional performance. As well as we compare nuclear emulsion with other directional detectors: in terms of direction preservation nuclear emulsion outperforms the other detectors for WIMP masses above 100 GeV/c
2
.
We report the facile and non-covalent preparation of gold nanoparticles (AuNPs) stabilized by an antiparkinson codrug based on lipoic acid (LA). The obtained AuNPs appear stable in both dimethyl ...sulfoxide and fetal bovine serum and able to load an amount of codrug double the weight of gold. These NPs were demonstrated to be safe and biocompatible towards primary human blood cells and human neuroblastoma cells, one of the most widely used cellular models to study dopaminergic neural cells, therefore are ideal drug carriers for difficult to solubilize molecules. Very interestingly, the codrug-stabilized AuNPs were shown to reduce the accumulation of reactive oxygen species in SH-SY5Y cells treated with LD and did not change total oxidant status levels in cultured human blood cells, thus confirming the antioxidant role of LA although bound to AuNPs. The characterization of AuNPs in terms of loading and stability paves the way for their use in biomedical and pharmacological applications.
Recent developments of the nuclear emulsion technology led to the production of films with nanometric silver halide grains suitable to track low energy nuclear recoils with submicrometric length. ...This improvement opens the way to a directional Dark Matter detection, thus providing an innovative and complementary approach to the on-going WIMP searches. An important background source for these searches is represented by neutron-induced nuclear recoils that can mimic the WIMP signal. In this paper we provide an estimation of the contribution to this background from the intrinsic radioactive contamination of nuclear emulsions. We also report the neutron-induced background as a function of the read-out threshold, by using a GEANT4 simulation of the nuclear emulsion, showing that it amounts to about 0.06 per year per kilogram, fully compatible with the design of a 10 kg × year exposure.
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