Although a better fit to the Monte Carlo distributions is obtained by using the sum of a Gaussian and an exponential (i.e., the data suggest exponential rather than Gaussian tails ), for signal extraction using Monte Carlo signal pdfs we need only the Gaussian, since we are just trying to characterize differences between Monte Carlo distributions and calibration data distributions. As already described, in signal extraction we use these differences to evaluate the systematic uncertainties on the fitted event rates by convolving the Monte Carlo–generated pdfs with smearing functions designed to broaden and shift the Monte Carlo-simulated position distributions so that they look like those we have obtained with the data. In other words, we fit for the function F for both Monte Carlo simulation and calibration data, and then find the Gaussian that smears the Monte Carlo–derived F to yield the F we measure for the data. This “smearing” Gaussian is then convolved with the Monte Carlo–generated signal position pdfs (the second row of Fig. 2) and the signal-extraction procedure is repeated. The resultant change in the fiducial volume and the number of extracted neutrino events yields the uncertainty on the neutrinofluxes.
separation angle). A stacking method (fixing both the neutrino and the UHECT directions) has been also used to maximize the likelihood varying the fraction of correlating events. Plausible assumptions about angular dispersion are required to account for direction tolerances. First reports pointed to inter- esting correlations  that have nevertheless become weaker in a recent update of the analysis . Searches for anisotropies of UHECR are revealing precious information about their production sites but more data are needed. The Auger Observatory is e ff ective to constrain models searching for di ff use neutrinofluxes and for point sources as part of a multi-messenger approach. As data from the Observatory continue to be analyzed and combined with other experiments we will get closer to deciphering the elusive origin of the most energetic particles in the Universe.
As shown in the left panel of figure 4 the experimental results are compatible with the predictions for both the low Z and high Z models; this means that it is not possible to definitely solve this ambiguity only by looking at 7 Be and 8 B fluxes. A breakthrough would come with the measurement of the CNO neutrinofluxes, as shown in the right panel of figure 4. This graph also indicates that a parallel improvement in the determination of one of the two fluxes, measurable with the JUNO detector, would bring a complementary piece of information, essential to discriminate the ambiguity between high Z models and models, predicting low Z metallicity with modified opacity.
work includes events with any particles beyond the sin- gle π 0 and muon, the MiniBooNE and ANL measure- ments excluded events with additional charged-mesons. The published neutrinofluxes [14, 43] as implemented in Ref.  have been used to derive flux averaged cross sec- tion prediction and the results from deuterium, carbon, and argon are shown together in Fig. 4. Each experiment integrates their unique flux across different energy ranges, which complicates the ability to directly scale between nuclear targets. The model comparisons in Fig. 4 employ the same flux integrations as used to treat the data. The ANL and MiniBooNE measurements agree with both of the GENIE predictions, whereas a slight deficit (1.2σ) relative to these models is seen for argon. The measured cross sections on deuterium and argon are in agreement with the NuWro predictions, while the measurement on carbon sits 1.2σ high. This indicates that the scalings implemented in these models are applicable, within the uncertainties, for neutrino-argon scattering.
To predict neutrinofluxes and energy spectra, a neutrino beam Monte Carlo simulation, called JNUBEAM , was developed based on the GEANT3 framework . We compute the neutrino beam fluxes starting from models (FLUKA [15, 16] and GCALOR ) and tuning them to experimental data (NA61/SHINE  and Eichten et al. ). Energy spectra at the center and end of the horizontal modules are shown in Fig. 10. Because each module covers a different off-axis angle, the neutrino energy spectrum at each module location is different. The difference in the average neutrino energy between the center module and the end module is about 0.2 GeV. Energy spectra at 10 m upstream from INGRID are predicted with the same procedure in order to simulate the background events from neutrino interactions in the wall of the experimental hall.
The fit also included seven nuisance parameters to ac- count for uncertainties in the neutrinofluxes, plus one for the DOM efficiency. These were the normalizations for the conventional and prompt atmospheric fluxes and the astrophysical flux, the cosmic-ray spectral index, and the K/π and ν/ν ratio for conventional neutrinos, and the as- trophysical flux spectral index. An additional nuisance pa- rameter accounts for uncertainties in the overall DOM op- tical sensitivity.
entry and exit points and the triggering of the outward looking tubes (OWLs). Since we want to be able to see the neutrons produced at the interaction point and measure the lepton energy, I look for only fully contained events. These are events where the neutrino interacts within the instrumented volume, and the produced lepton deposits all of its energy without leaving the detector. Although the OWL tubes can no longer be used to select the event, an event sample with very few backgrounds can still be selected using the high energy of the events of interest. The mean neutrino energy in atmospheric neutrino interactions is 1.4 GeV, making these events much more energetic on average than almost every other physics event. I select only events with at least 200 PMT hits, or “N hit .” It was found that 66.9%
Even though our analysis is independent of the normalization of the atmos- pheric neutrino flux, in order to produce spectra based on numbers of events, as in the following subsection, some normalization of the total flux is neces- sary. For standard oscillations without quantum decoherence, bins with high E/ cos ϑ can be used to normalize the flux as standard oscillations are negli- gible at sufficiently high E/L (as can be seen in figure 1). This method can also be applied for quantum decoherence models in which the decoherence parameters are inversely proportional to the neutrino energy, so that decoher- ence also becomes negligible at high energy. However, when the decoherence parameters are proportional to the neutrino energy squared, decoherence is significant at high energies but negligible at low E/L. Therefore, in this latter case, we may use the low E/ cos ϑ bins to normalize the flux.
Neutrino telescopes (NT) are gigantic open 3D arrays of photomultiplier tubes (PMTs) enclosed in pressure resistant glass spheres, referred to as optical modules (OMs). Rela- tivistic particles are detected collecting the Cherenkov light induced by these particles in a transparent medium such as water or ice. In the search for neutrino interactions, atmospheric muons produced by the interaction of cosmic rays in the atmosphere are therefore the most abundant source of background. In order to mitigate it, the detectors are buried deep under the surface, and neutrinos are searched for as upgoing particles. Hence, NT are most e ffi ciently monitoring one half of the sky in the TeV-PeV range. This restriction can be overpassed re- quiring a containment condition at the expense of a narrower energy range, focusing on the most energetic particles only. The interacting neutrinos produce two classes of events: tracks and cascades (also called showers). Track-like events are those where a long-ranged muon is observed, and allow for the precise measurement of its detection. This is the golden channel for astronomy. Most of these events are produced by charged-current interaction of muon neutrinos.
The high-level criteria used to classify events were introduced in Section 220.127.116.11. While in previous work these parameters have been used largely to cut low-energy backgrounds due to radioactive decays (see e.g. References  and ), here they are used to reduce the atmospheric neutrino background to the single-electron signal. Therefore we must reconsider which high-level parameters are useful, and certainly re-optimize the cut values. Happily, due to the higher energies involved, this generally means tightening the bounds. The cuts represent several orthogonal ways to ask whether an event is compatible with the hypothesis of a single electron. Atmospheric neutrino interactions that produce, for example, multiple Cherenkov rings, short-lived decays that pile up in the same event window, or muons break this hypothesis and these events tend to reconstruct poorly and fail these event quality cuts; Figure 8.1 shows a few examples of such background event classes. Clearly an approach able to interpret multi-ring events would be an improvement, but these na¨ıve cuts are effective for reducing the atmospheric background to a fraction of an event in the 1/3 non-blinded dataset.
Abstract. In September 22, 2017, IceCube released a public alert announcing the detection of a 290 TeV neutrino track event with an angular uncertainty of one square degree (90% containment). A multi-messenger follow-up campaign was initiated resulting in the detection of a GeV gamma-ray flare by the Fermi Large Area Telescope positionally consistent with the location of the known Bl Lac object, TXS 0506+056 , located only 0.1 degrees from the best-fit neutrino position. The probability of finding a GeV gamma-ray flare in coincidence with a high-energy neutrino event assuming a correlation of the neutrino flux with the gamma-ray energy flux in the energy band between 1 and 100 GeV was calculated to be 3σ (after trials correction). Following the detection of the flaring blazar the imaging air Cherenkov telescope MAGIC detected the source for the first time in the > 100 GeV gamma-ray band. The activity of the source was confirmed in X-ray, optical and radio wavelength. Several groups have developed lepto-hadronic models which succeed to explain the multi-messenger spectral energy distribution.
The solar neutrino problem was not solved until approximately 30 years after the start of the Homestake experiment. Super-Kamiokande, a detector 15 times heavier than its predecessor Kamiokande, started operations in 1996. Super-Kamiokande is a cylindrical stainless steel tank containing 50,000 tons of ultrapure water and surrounded by 11,146 photomultipliers (PMTs) that remains in operation to this day. Neutrinos are identified by the Cherenkov light cones that charged particles originating in neutrino interactions produce while traveling in the water. In 1998, the Super-Kamiokande experiment produced solid evidence for the disappearance of muon-neutrinos produced in the atmosphere . An atmospheric neutrino deficit had been seen previously by other experiments such as IMB , MACRO  and Soudan-2 . It was not until Super-Kamiokande however that the zenith angle dependence of the deficit was clearly established, as shown in Figure 2.4. This meant that atmospheric ν µ ’s were disappearing as a function of the distance traveled from
the depth of the tunnels, which has cost implications. The proposed decay ring is 1 300 m in circumference and accommodates the equally-spaced, 250 ns long, bunch trains with time intervals of at least 120 μs between the neutrino bursts. The production straights for the race-track design are ∼ 470 m long, giving an efficiency per sign of stored muon of 36.15%. The tunnel depth for a ring of this size is around 100 m. To keep the neutrino beams reasonably well focused, the muon-beam rms divergence should not add more than ∼10% to the natural width of the decay cone. This means that the β function, which should be small ( ∼10 m) in the arcs, has to be matched to values of about 80 m at the start of the long production straights which can be achieved by matching sections at the end of each straight. Simulations of the racetrack decay ring have been carried out using the code Zgoubi . Additional simulations showed that, given the predicted energy spread of the muon beams, the bunches in the bunch train will not merge (bunch separation larger 100 ns) before twice the lifetime of the muons and therefore no RF has to be installed in the decay ring. In the future, tracking studies will address the machine’s dynamic aperture including errors. Additionally an efficient collimation system needs to be developed to cope with the muon beam power that the rings have to sustain. More information concerning the decay rings can be found in .
Introduction—The discovery of neutrino oscillations using atmospheric neutrinos was made by Super- Kamiokande in 1998 . Since then, many other exper- iments have confirmed the phenomenon of neutrino os- cillations through various disappearance modes of flavor transformations. However, to date, there has not been an observation of the explicit appearance of a different neu- trino flavor from neutrinos of another flavor through neu- trino oscillations. In 2011, the T2K collaboration pub- lished the first indication of electron neutrino appearance from a muon neutrino beam at 2.5σ significance based on a data set corresponding to 1.43 ×10 20 protons on target
increased cross section, the neutron capture on 35 Cl resulted in a cascade of γ -rays summing to a higher energy of 8.6 MeV, better separating this signal from radioactive backgrounds. Phase III added a neutral current detector (NCD) array inside the active volume for an independent measure of neutron production inside the detector. These NCDs were high-purity nickel tubes containing 3 He gas, and they were instrumented to utilize the 3 He as a propor- tional counter for thermal neutrons . For Phase III only there are two sources of detector data: the PMT array data as in Phase I and Phase II and the NCD array data. As these datasets are treated differently in analyses, the PMT data from Phase III will be referred to simply as Phase III with the NCD data being Phase IIIb. A combined analysis of Phase I and II data led to a low-energy measurement of the electron neutrino survival probability . That analysis was later extended to incorporate Phase III data , and the analysis described in this paper was based on the analysis described in .
To solve the problem of the origin of homochirality of living systems and life itself, it is necessary to rethink the conceptual foundations of physics dialectically. The review shows how this can be done within the framework of the paradigm of energoforms, which sets the principles of construction and mathematical formalization of the Heraclitus primary element of matter. The algorithm for modeling energoforms and structures of elementary particles was created based on the laws of dialectics, electromagnetic induction and the rules of quantum physics. The algorithm allowed to calculate the parameters of chiral structures of neutron, proton, electron, neutrino and photon in the ground and excited states, as well as the parameters of more than one hundred nuclei. As an adequate solution to the problems of neutrino physics and the nature of the universal chiral factor, we hypothesized the instability of the low-energy solar neutrino and the biogenicity of its decay products – chiral energoforms. The hypothesis was based on correlations of seasonal and daily variations of solar neutrino flux, optical activity of aqueous solutions of sugars and metabolism of plants and animals. In humans, chiral morphofunctional features that limit homeostasis and the rhythm of energy-informational connections of the brain with the external environment were revealed. It was shown that the mechanism of sensitivity of living matter to the action of chiral factor is based on the ability to self-organization of its cooperative water- containing systems consisting of spin homogeneous chiral elements.
demonstrated by the ANTARES neutrino telescope which is operational in the Mediterranean Sea since 2007 . Building on this experience the KM3NeT research infrastructure  has been planned and is currently under construction. It will host two neutrino telescope installations: ARCA (Astroparticle Research with Cosmics in the Abyss) at an Italian site located about 100 km from Capo Passero (Sicily, Italy) at a depth of 3500 m, focussed on the measurement of high energetic astrophysical neutrinos and ORCA (Oscillations Research with Cosmics in the Abyss) at a French site located about 40 km from Toulon (France) at a depth of 2475 m, focussed on low energetic atmospheric neutrinos. The same technology will be used at both sites but different detector densities will be implemented optimized for the different addressed energy ranges.
In this paper, OPERA results have been used to derive limits on the oscillations induced by a sterile neutrino, obtaining 90% C.L. exclusion regions for three diﬀerent parameter spaces. The eﬀective mixing parameter of the 3 + 1 neutrino model, for Δm 2 41 > 1 eV 2 , is constrained at 90% C.L. at sin 2 2θ μτ < 0.119. Based on this upper limit, constraints on |U τ4 | 2 and |U μ4 | 2 have also been set.
The J-PARC neutrino beamline has two complementary subsystems. These are: the primary and secondary beamlines. The main aim of the primary beamline is to tune proton beam coming from J-PARC accelerator, bent it towards the direction of Kamioka, and focus the beam onto the target. In the secondary beamline we can distinguish three sections: the target station, decay volume and beam dump. The target station is equipped with three magnetic horns and the graphite target, 90 cm in length, which is inserted inside the first one. When proton beam is impinging on the graphite target many hadrons are produced, amongst of which charged pions and kaons are crucial as neutrino parents. At the beginning of the T2K data taking horns were working at 250 kA current pulse in order to focus positively charged hadrons to produce a muon neutrino enhanced beam ν µ . An anti-neutrino
The first project which we will discuss uses the scale of neutrino mass to place model-independent constraints on the coefficients of the chirality-changing terms in the muon decay Lagrangian. We list all of the dimension-six effective operators which contribute to muon decay and Dirac mass for the neutrino. We then calculate the one-loop contributions that each of these operators makes to neutrino mass. Taking a generic element of the neutrino mass matrix to be of order ∼ 1 eV, we derive limits on the contributions of these operators to the muon Michel parameters which are approximately four orders of magnitude more stringent than the current experimental results, and well below near-future experimental sensitivity. We also find two chirality- changing operators, which, due to their flavor structure, are unconstrained by neutrino mass yet contribute to muon decay. However, as these two operators differ from those constrained by neutrino mass only by their flavor indices, we naively expect their contributions to also be small; if their effects instead turn out to be observable, this may be an indication of beyond-the-Standard-Model physics with an interesting flavor structure.