Search

The Radio Neutrino Observatory – Greenland (RNO-G) seeks discovery of ultra-high energy neutrinos from the cosmos through their interactions in ice. The science program extends beyond particle astrophysics to include radioglaciology and, as we show herein, solar observations, as well. Currently seven of 35 planned radio-receiver stations (24 antennas/station) are operational. These stations are sensitive to impulsive radio signals with frequencies between 80 and 700 MHz and feature a neutrino trigger threshold for recording data close to the thermal floor. RNO-G can also trigger on elevated signals from the Sun, resulting in nanosecond resolution time-domain flare data; such temporal resolution is significantly shorter than from most dedicated solar observatories. In addition to possible RNO-G solar flare polarization measurements, the Sun also represents an extremely useful above-surface calibration source. Using RNO-G data recorded during the summers of 2022 and 2023, we find signal excesses during solar flares reported by the solar-observing Callisto network and also in coincidence with ∼ 2/3 of the brightest excesses recorded by the SWAVES satellite. These observed flares are characterized by significant time-domain impulsivity. Using the known position of the Sun, the flare sample is used to calibrate the RNO-G absolute pointing on the radio signal arrival direction to sub-degree resolution. We thus establish the Sun as a regularly observed astronomical calibration source to provide the accurate absolute pointing required for neutrino astronomy. [ABSTRACT FROM AUTHOR]

The primary goal of the novel photosensor technology called ABALONE™ (U.S. Pat. 9,064,678) has been to enable the next-generation of astroparticle physics experiments to open new windows on the universe with large-area detectors of unprecedented performance, including radio-purity, robustness, and integration flexibility. This foundational technology provides the means for modern, scalable and cost-effective production. The wide range of possible application-specific detector configurations can also make a difference in homeland security and medical imaging. Thus far, we have reduced to practice two such detector configurations: (i) the composite sandwich Panel assembly that hosts matrices of closely packed ABALONE units (U.S. Pat. 10,823,861), and, quite differently, the Tandem Detector Modules that host two back-to-back oriented ABALONE photosensors. This article for the first time presents the latter configuration, specifically designed to provide 2 × 2 π angular acceptance for neutrino astronomy and other large-area radiation detectors. [ABSTRACT FROM AUTHOR]

The recent hint of correlated γ -ray and neutrino emission from the blazar TXS 0506+056 has renewed interest in blazars as the source of high-energy neutrinos, in which the possible neutrino emission involved hadronic acceleration in the jet of blazars. In this review, we summarize the recent advances in the multi-wavelength and neutrino observations of blazars. We focus on the discussion of the current understanding of blazar emission processes in the leptonic and hadronic model. The future multi-messenger observations combining electromagnetic and neutrino measurements will help us to constrain blazar emission models and understand the origins of the high-energy γ -rays and neutrinos. [ABSTRACT FROM AUTHOR]

A novel method to analyse the spatial distribution of neutrino candidates recorded with the ANTARES neutrino telescope is introduced, searching for an excess of neutrinos in a region of arbitrary size and shape from any direction in the sky. Techniques originating from the domains of machine learning, pattern recognition and image processing are used to purify the sample of neutrino candidates and for the analysis of the obtained skymap. In contrast to a dedicated search for a specific neutrino emission model, this approach is sensitive to a wide range of possible morphologies of potential sources of high-energy neutrino emission. The application of these methods to ANTARES data yields a large-scale excess with a post-trial significance of 2.5 σ. Applied to public data from IceCube in its IC40 configuration, an excess consistent with the results from ANTARES is observed with a post-trial significance of 2.1 σ. [ABSTRACT FROM AUTHOR]

The successes of the ANTARES detector have demonstrated the feasibility and value of deep sea neutrino telescopes, as well as their versatility through Earth and Sea sciences. KM3NeT is a distributed undersea research infrastructure in the Mediterranean Sea that will host a network of next-generation neutrino telescopes. With the ORCA telescope at the KM3NeT-Fr site, the main objective is to determine the neutrinos mass hierarchy by studying atmospheric neutrino oscillations. The ARCA telescope at the KM3NeT-It site will allow for high energy neutrino astronomy. The telescopes consist of a regular 3D array of Digital Optical Modules, each composed of 31 photomultipliers, equally spaced along flexible lines anchored on the seabed. This multi-photomultipliers concept yields a factor three increase in photocathode area, compared to a design with a single 10 inch photomultiplier, leading to a significant cost reduction. Moreover, this concept allows for an accurate measurement of the light intensity and offers directional information with an almost isotropic field of view. A detailed overview of the detectors, their construction status and their physics program will be presented. The calibration techniques will be discussed, with an emphasis on time calibration, water properties and positioning measurements. [ABSTRACT FROM AUTHOR]

Abstract After the first measurement of the coherent elastic neutrino nucleus scattering (CENNS) by the COHERENT Collaboration, it is expected that new experiments will confirm the observation. Such measurements will allow to put stronger constraints or discover new physics as well as to probe the Standard Model by measuring its parameters. This is the case of the weak mixing angle at low energies, which could be measured with an increased precision in future results of CENNS experiments using, for example, reactor antineutrinos. In this work we analyze the physics potential of different proposals for the improvement of our current knowledge of this observable and show that they are very promising. [ABSTRACT FROM AUTHOR]

We consider the ratio of the spectra measured in the DANSS neutrino experiment at 12.7 and 10.7 m from a nuclear reactor. These data give a new model-independent indication in favor of short-baseline ν ¯ e oscillations which reinforce the model-independent indication found in the late 2016 in the NEOS experiment. The combined analysis of the NEOS and DANSS spectral ratios in the framework of 3+1 active–sterile neutrino mixing favor short-baseline ν ¯ e oscillations with a statistical significance of 3.7 σ . The two mixing parameters sin 2 ⁡ 2 ϑ e e and Δ m 41 2 are constrained at 2 σ in a narrow- Δ m 41 2 island at Δ m 41 2 ≃ 1.3 eV 2 , with sin 2 ⁡ 2 ϑ e e = 0.049 ± 0.023 (2 σ ). We discuss the implications of the model-independent NEOS+DANSS analysis for the reactor and Gallium anomalies. The NEOS+DANSS model-independent determination of short-baseline ν ¯ e oscillations allows us to analyze the reactor rates without assumptions on the values of the main reactor antineutrino fluxes and the data of the Gallium source experiments with free detector efficiencies. The corrections to the reactor neutrino fluxes and the Gallium detector efficiencies are obtained from the fit of the data. In particular, we confirm the indication in favor of the need for a recalculation of the U 235 reactor antineutrino flux found in previous studies assuming the absence of neutrino oscillations. [ABSTRACT FROM AUTHOR]

We propose a local U ( 1 ) L μ − L τ model to explain b → s μ + μ − anomaly observed at the LHCb and Belle experiments. The model also has a natural dark matter candidate N . We introduce S U ( 2 ) L -doublet colored scalar q ˜ to mediate b → s transition at one-loop level. The U ( 1 ) L μ − L τ gauge symmetry is broken spontaneously by the scalar S . All the new particles are charged under U ( 1 ) L μ − L τ . We can obtain C 9 μ , NP ∼ − 1 to solve the b → s μ + μ − anomaly and can explain the correct dark matter relic density of the universe, Ω DM h 2 ≈ 0.12 , simultaneously, while evading constraints from electroweak precision tests, neutrino trident experiments and other quark flavor-changing loop processes such as b → s γ and B s − B ‾ s mixing. Our model can be tested by searching for Z ′ and new colored scalar at the LHC and B → K ⁎ ν ν ‾ process at Belle-II. [ABSTRACT FROM AUTHOR]

We propose a grand unified SU ( 5 ) × U ( 1 ) X model, where the standard SU(5) grand unified theory is supplemented by minimal seesaw and a right-handed neutrino dark matter with an introduction of a global Z 2 -parity. In the presence of three right-handed neutrinos (RHNs), the model is free from all gauge and mixed-gravitational anomalies. The SU(5) symmetry is broken into the Standard Model (SM) gauge group at M GUT ≃ 4 × 10 16 GeV in the standard manner, while the U(1) X symmetry breaking occurs at the TeV scale, which generates the TeV-scale mass of the U(1) X gauge boson ( Z ′ boson) and the three Majorana RHNs. A unique Z 2 -odd RHN is stable and serves as the dark matter (DM) in the present Universe, while the remaining two RHNs work to generate the SM neutrino masses through the minimal seesaw. We investigate the Z ′ -portal RHN DM scenario in this model context. We find that the constraints from the DM relic abundance, and the Z ′ boson search at the Large Hadron Collider (LHC), and the perturbativity bound on the U(1) X gauge coupling are complementary to narrow down the allowed parameter region in the range of 3.0 ≤ m Z ′ [ TeV ] ≤ 9.2 for the Z ′ boson mass. The allowed region for m Z ′ ≤ 5 TeV will be fully covered by the future LHC experiments. We also briefly discuss the successful implementation of Baryogenesis and cosmological inflation scenarios in the present model. [ABSTRACT FROM AUTHOR]

We investigate the generation of small neutrino masses in a clockwork framework which includes Dirac mass terms as well as Majorana mass terms for the new fermions. We derive analytic formulas for the masses of the new particles and for their Yukawa couplings to the lepton doublets, in the scenario where the clockwork parameters are universal. When the universal Majorana mass vanishes, the zero mode of the clockwork sector forms a Dirac pair with the active neutrino, with a mass which is in agreement with oscillations experiments for a sufficiently large number of clockwork gears. On the other hand, when it does not vanish, neutrino masses are generated via the seesaw mechanism. In this case, and due to the fact that the effective Yukawa couplings of the higher modes can be sizable, neutrino masses can only be suppressed by postulating a large Majorana mass scale. Finally, we discuss the constraints on the mass scale of the clockwork fermions from the non-observation of the rare leptonic decay μ → e γ . [ABSTRACT FROM AUTHOR]

The Sun is a main source of high energy neutrinos. These neutrinos appear as secondary particles after the Sun absorbs high-energy cosmic rays, that find there a low-density environment (much thinner than our atmosphere) where most secondary pions, kaons and muons can decay before they lose energy. The main uncertainty in a calculation of the solar neutrino flux is due to the effects of the magnetic fields on the absorption rate of charged cosmic rays. We use recent data from HAWC on the cosmic-ray shadow of the Sun to estimate this rate. We evaluate the solar neutrino flux and show that at 1 TeV it is over ten times larger than the atmospheric one at zenith θ z = 30 ∘ / 150 ∘ . The flux that we obtain has a distinct spectrum and flavor composition: it is harder and richer in antineutrinos and tau/electron neutrinos than the atmospheric background. This solar flux could be detected in current and upcoming neutrino telescopes. KM3NeT, in particular, looks very promising: it will see the Sun high in the sky (the atmospheric flux is lower there than near the horizon) and expects a very good angular resolution (the Sun’s radius is just 0.27°). [ABSTRACT FROM AUTHOR]

The KM3NeT collaboration is building a km 3 -scale neutrino telescope in the Mediterranean Sea. The current phase of construction comprises the deep-sea and onshore infrastructures at two installation sites and the installation of the first detection units for the “ARCA” (Astroparticle Research with Cosmics in the Abyss) and “ORCA” (Oscillation Research with Cosmics in the Abyss) detector. At the KM3NeT-It site, 80 km offshore Capo Passero, Italy, the first 32 detection units for the ARCA detector are being installed and at the KM3Net-Fr site, 40 km offshore Toulon, France, 7 detection units for the ORCA detector will be deployed. The second phase of KM3NeT foresees the completion of ARCA for neutrino astronomy at energies above TeV and ORCA for neutrino mass hierarchy studies at energies in the GeV range. The basic element of the KM3NeT detector is the detection unit. In the ARCA geometry, the detection unit is a 700 m long vertical structure hosting 18 optical modules. Each optical module comprises 31 3 in photomultiplier tubes, instruments to monitor environmental parameters, and the electronic boards for the digitisation of the PMT signals and the management of data acquisition. In their final configuration, both ARCA and ORCA will be composed of about 200 detection units. The first detection unit was installed at the KM3NeT-It site in December 2015. It is active and taking data since its connection to the subsea network. The time of arrival and the duration of photon hits on each of the photomultipliers is measured with a time resolution of 1 ns and transferred onshore where the measurements are processed, triggered and stored on disk. A time calibration procedure, based on data recorded with flashing LED beacons during dedicated periods, allows for time synchronisation of the signals from the optical modules at the nanosecond level. In May 2016, an additional detection unit was installed at the KM3NeT-It site. The first results with two active detection units are presented. An update of the detector status and construction is given. [ABSTRACT FROM AUTHOR]

The IceCube Neutrino Observatory is a cubic-kilometer neutrino telescope located at the geographic South Pole. Buried deep under the Antarctic ice sheet, an array of 5160 Digital Optical Modules (DOMs) is used to capture the Cherenkov light emitted by relativistic particles generated from neutrino interactions. The main goal of IceCube is the detection of astrophysical neutrinos. In 2013 the IceCube neutrino telescope discovered a high-energy diffuse flux of neutrino events with energy ranging from tens of TeV up to few PeV of cosmic origin. Meanwhile, different analyses confirm the discovery and search for possible correlations with astrophysical sources. However, the source of these neutrinos remains a mystery, since no counterparts have been identified yet. In this contribution we give an overview of the detection principles of IceCube, the most recent results, and the plans for a next-generation neutrino detector, dubbed IceCube-Gen2. [ABSTRACT FROM AUTHOR]

Neutrino-dominated accretion flows (NDAFs) around rotating stellar-mass black holes (BHs) are plausible candidates for the central engines of gamma-ray bursts (GRBs). NDAFs are hyperaccretion disks with accretion rates in the range of around 0.001–10 M ⊙ s − 1 , which have high density and temperature and therefore are extremely optically thick and geometrically slim or even thick. We review the theoretical progresses in studying the properties of NDAFs as well as their applications to the GRB phenomenology. The topics include: the steady radial and vertical structure of NDAFs and the implications for calculating neutrino luminosity and annihilation luminosity, jet power due to neutrino-antineutrino annihilation and Blandford–Znajek mechanism and their dependences on parameters such as BH mass, spin, and accretion rate, time evolution of NDAFs, effect of magnetic fields, applications of NDAF theories to the GRB phenomenology such as lightcurve variability, extended emission, X-ray flares, kilonovae, etc., as well as probing NDAFs using multi-messenger signals such as MeV neutrinos and gravitational waves. [ABSTRACT FROM AUTHOR]

We present calculations showing how electron rest mass influences entropy flow, neutrino decoupling, and Big Bang Nucleosynthesis (BBN) in the early universe. To elucidate this physics and especially the sensitivity of BBN and related epochs to electron mass, we consider a parameter space of rest mass values larger and smaller than the accepted vacuum value. Electromagnetic equilibrium, coupled with the high entropy of the early universe, guarantees that significant numbers of electron–positron pairs are present, and dominate over the number of ionization electrons to temperatures much lower than the vacuum electron rest mass. Scattering between the electrons–positrons and the neutrinos largely controls the flow of entropy from the plasma into the neutrino seas. Moreover, the number density of electron–positron-pair targets can be exponentially sensitive to the effective in-medium electron mass. This entropy flow influences the phasing of scale factor and temperature, the charged current weak-interaction-determined neutron-to-proton ratio, and the spectral distortions in the relic neutrino energy spectra. Our calculations show the sensitivity of the physics of this epoch to three separate effects: finite electron mass, finite-temperature quantum electrodynamic (QED) effects on the plasma equation of state, and Boltzmann neutrino energy transport. The ratio of neutrino to plasma–component energy scales manifests in Cosmic Microwave Background (CMB) observables, namely the baryon density and the radiation energy density, along with the primordial helium and deuterium abundances. Our results demonstrate how the treatment of in-medium electron mass (i.e., QED effects) could translate into an important source of uncertainty in extracting neutrino and beyond-standard-model physics limits from future high-precision CMB data. [ABSTRACT FROM AUTHOR]

We discuss a novel alternative method of determining the neutrino mass ordering in medium baseline experiments with reactor antineutrinos. Results on the potential sensitivity of the new method are also presented. [ABSTRACT FROM AUTHOR]

In the Next-to-Minimal-Supersymmetric-Standard-Model (NMSSM) the lightest supersymmetric particle (LSP) is a candidate for the dark matter (DM) in the universe. It is a mixture from the various gauginos and Higgsinos and can be bino-, Higgsino- or singlino-dominated. Singlino-dominated LSPs can have very low cross sections below the neutrino background from coherent neutrino scattering which is limiting the sensitivity of future direct DM search experiments. However, previous studies suggested that the combination of both, the spin-dependent (SD) and spin-independent (SI) searches are sensitive in complementary regions of parameter space, so considering both searches will allow to explore practically the whole parameter space of the NMSSM. In this letter, the different scenarios are investigated with a new scanning technique, which reveals that significant regions of the NMSSM parameter space cannot be explored, even if one considers both, SI and SD, searches. [ABSTRACT FROM AUTHOR]

Recent results in the field of high energy active galactic nuclei (AGN) astrophysics, benefiting from improvements to gamma-ray instruments and observational strategies, have revealed a surprising wealth of unexpected phenomena. These developments have been brought about both through observational efforts to discover new very high energy gamma-ray emitters, as well as from further in-depth observations of previously detected and well studied objects. I here focus specifically on the discovery of repeated temporal structures observed in AGN lightcurves, and new hard spectral components within the spectral energy distributions of other AGN systems. The challenges that these new features place on the modeling of the sources are highlighted, along with some reflections on what these results tell us about the underlying nature of the emission processes at play. [ABSTRACT FROM AUTHOR]

We propose a three-loop neutrino mass model with a few leptoquark scalars in S U ( 2 ) L -triplet form, through which we can explain the anomaly of B → K ( ⁎ ) μ + μ − , a sizable muon g − 2 and a bosonic dark matter candidate, and at the same time satisfying all the constraints from lepton flavor violations. We perform global numerical analyses and show the allowed regions, in which we find somewhat restricted parameter space, such as the mass of dark matter candidate and various components of the Yukawa couplings in the model. [ABSTRACT FROM AUTHOR]

Testable Higgs partners may be sought within the extensions of the SM Higgs sector aimed at generating neutrino masses at the loop level. We study a viability of extended Higgs sectors for two selected models of radiative neutrino masses: a one-loop mass model, providing the Higgs partner within a real triplet scalar representation, and a three-loop mass model, providing it within its two-Higgs-doublet sector. The Higgs sector in the one-loop model may remain stable and perturbative up to the Planck scale, whereas the three-loop model calls for a UV completion around 10 6 GeV . Additional vector-like lepton and exotic scalar fields, which are required to close one- and three-loop neutrino-mass diagrams, play a decisive role for the testability of the respective models. We constrain the parameter space of these models using LHC bounds on diboson resonances. [ABSTRACT FROM AUTHOR]

The ARIANNA hexagonal radio array (HRA) is an experiment in its pilot phase designed to detect cosmogenic neutrinos of energies above 10 16 eV. The most neutrino-like background stems from the radio emission of air showers. This article reports on dedicated efforts of simulating and detecting the signals of cosmic rays. A description of the fully radio self-triggered data-set, the properties of the detected air shower signals in the frequency range of 100–500 MHz and the consequences for neutrino detection are given. 38 air shower signals are identified by their distinct waveform characteristics, are in good agreement with simulations and their signals provide evidence that neutrino-induced radio signals will be distinguishable with high efficiency in ARIANNA. The cosmic ray flux at a mean energy of 6 . 5 − 1.0 + 1.2 × 10 17 eV is measured to be 1 . 1 − 0.7 + 1.0 × 10 − 16 eV − 1 km − 2 sr − 1 yr − 1 and one five-fold coincident event is used to illustrate the capabilities of the ARIANNA detector to reconstruct arrival direction and energy of air showers. [ABSTRACT FROM AUTHOR]

Evidence is presented in support of an unconventional 3 + 3 model of the neutrino mass eigenstates with specific m 2 > 0 and m 2 < 0 masses. The two large m 2 > 0 masses of the model were originally suggested based on a SN 1987A analysis, and they were further supported by several dark matter fits. The new evidence for one of the m 2 > 0 mass values comes from an analysis of published data from the three most precise tritium β − decay experiments. The KATRIN experiment by virtue of a unique 3-part signature should either confirm or reject the model in its entirety. [ABSTRACT FROM AUTHOR]

The CYGNO project aims at realizing a one cubic meter gaseous Time Projection Chamber (TPC) equipped with Scientific CMOS (sCMOS) commercial cameras to optically readout Gas Electron Multiplier (GEM) to be operated at the underground of Gran Sasso National Laboratory (LNGS). The purpose of the project is to study the technology needed for a large size gaseous TPC (30–100 m 3) operated at atmospheric pressure for the directional search of low mass O(GeV) dark matter and low energy (eg solar) neutrinos astronomy. The roadmap of the project foresees the underground operation of a 50 litres TPC prototype, called LIME, the largest TPC realized with this technology, fully equipped with copper and water shielding. LIME is equivalent to about a 1/20 of the CYGNO demonstrator and aims to validate: The construction materials, the Monte Carlo simulations, the data reconstruction and the particle identification performances at low energy threshold. LIME is under installation at the LNGS and it is supposed to start data taking at the beginning of 2022. The detector description and installation will be presented, as well as the overground performance and limitations that require underground characterization. [ABSTRACT FROM AUTHOR]

We show that mixing transformations for Dirac fields arise as a consequence of the non-trivial interplay between rotations and Bogoliubov transformations at level of ladder operators. Indeed the non-commutativity between the algebraic generators of such transformations turns out to be responsible of the unitary inequivalence of the flavor and mass representations and of the associated vacuum structure. A possible thermodynamic interpretation is also investigated. [ABSTRACT FROM AUTHOR]

We consider the possibility of solar neutrino decay as a sub-leading effect on their propagation between production and detection. Using current oscillation data, we set a new lower bound to the ν 2 neutrino lifetime at τ 2 / m 2 ≥ 7.2 × 10 − 4 s . eV − 1 at 99 % C.L. Also, we show how seasonal variations in the solar neutrino data can give interesting additional information about neutrino lifetime. [ABSTRACT FROM AUTHOR]

The IceCube Neutrino Observatory has discovered a diffuse all-flavor flux of high-energy astrophysical neutrinos. However, the corresponding astrophysical sources have not yet been identified. Neither significant point sources nor significant angular correlations of event directions have been observed by IceCube or other instruments to date. We present a new method to interpret the non-observation of angular correlations in terms of exclusions on the strength and number of point-like neutrino sources in generic astrophysical scenarios. Additionally, we constrain the presence of these sources taking into account the measurement of the diffuse high-energy neutrino flux by IceCube. We apply the method to two types of astrophysically motivated source count distributions: The first type is obtained by considering the cosmological evolution of the co-moving density of active galaxies, while the second type is directly derived from the gamma ray source count distribution observed by Fermi-LAT. As a result, we constrain the possible parameter space for both types of source count distributions. [ABSTRACT FROM AUTHOR]

We study a set of exclusive decay modes of the Standard Model Higgs boson into a vector meson and a dilepton pair: h → V ℓ + ℓ − , with V = ϒ , J / ψ , ϕ , and ℓ = μ , τ , determining the decay rates, the dilepton mass spectra and the V longitudinal helicity fraction distributions. In the same framework, we analyze the exclusive modes into neutrino pairs h → V ν ν ¯ . We also discuss the implications of the recent CMS and ATLAS results for the lepton flavor-changing process h → τ + μ − on the h → V τ + μ − decay modes. [ABSTRACT FROM AUTHOR]

A highly significant excess of high-energy astrophysical neutrinos has been reported by the IceCube Collaboration. Some features of the energy and declination distributions of IceCube events hint at a North/South asymmetry of the neutrino flux. This could be due to the presence of the bulk of our Galaxy in the Southern hemisphere. The ANTARES neutrino telescope, located in the Mediterranean Sea, has been taking data since 2007. It offers the best sensitivity to muon neutrinos produced by galactic cosmic ray interactions in this region of the sky. In this letter a search for an extended neutrino flux from the Galactic Ridge region is presented. Different models of neutrino production by cosmic ray propagation are tested. No excess of events is observed and upper limits for different neutrino flux spectral indices Γ are set. For Γ = 2.4 the 90% confidence level flux upper limit at 100 TeV for one neutrino flavour corresponds to Φ 0 1 f ( 100 TeV ) = 2.0 ⋅ 10 − 17 GeV − 1 cm − 2 s − 1 sr − 1 . Under this assumption, at most two events of the IceCube cosmic candidates can originate from the Galactic Ridge. A simple power-law extrapolation of the Fermi-LAT flux to account for IceCube High Energy Starting Events is excluded at 90% confidence level. [ABSTRACT FROM AUTHOR]

We present a real-time supernova neutrino burst monitor at Super-Kamiokande (SK). Detecting supernova explosions by neutrinos in real time is crucial for giving a clear picture of the explosion mechanism. Since the neutrinos are expected to come earlier than light, a fast broadcasting of the detection may give astronomers a chance to make electromagnetic radiation observations of the explosions right at the onset. The role of the monitor includes a fast announcement of the neutrino burst detection to the world and a determination of the supernova direction. We present the online neutrino burst detection system and studies of the direction determination accuracy based on simulations at SK. [ABSTRACT FROM AUTHOR]

Blazars, a subclass of active galactic nuclei, are prime candidate sources for the high energy neutrinos recently detected by IceCube. Being one of the brightest sources in the extragalactic X-ray and γ -ray sky as well as one of the nearest blazars to Earth, Mrk 421 is an excellent source for testing the scenario of the blazar-neutrino connection, especially during flares where time-dependent neutrino searches may have a higher detection probability. Here, we model the spectral energy distribution of Mrk 421 during a 13-day flare in 2010 with unprecedented multi-wavelength coverage, and calculate the respective neutrino flux. We find a correlation between the >1 PeV neutrino and photon fluxes, in all energy bands. Using typical IceCube through-going muon event samples with good angular resolution and high statistics, wederive the mean event rate above 100 TeV (∼0.57 evt/yr) and show that it is comparable to that expected from a four-month quiescent period in 2009. Due to the short duration of the flare, an accumulation of similar flares over several years would be necessary to produce a meaningful signal for IceCube. To better assess this, we apply the correlation between the neutrino and γ -ray fluxes to the 6.9 yr Fermi -LAT light curve of Mrk 421. We find that the mean event count above 1 PeV for the full IceCube detector livetime is 3.59 ± 0.60 (2.73 ± 0.38) ν μ + ν ¯ μ with (without) major flares included in our analysis. This estimate exceeds, within the uncertainties, the 95% (90%) threshold value for the detection of one or more muon (anti-)neutrinos. Meanwhile, the most conservative scenario, where no correlation of γ -rays and neutrinos is assumed, predicts 1.60 ± 0.16 ν μ + ν ¯ μ events. We conclude that a non-detection of high-energy neutrinos by IceCube would probe the neutrino/ γ -ray flux correlation during major flares or/and the hadronic contribution to the blazar emission. [ABSTRACT FROM AUTHOR]

The two long-baseline experiments T2K and NO ν A have recently presented new findings. T2K has shown the first ν ¯ e appearance data while NO ν A has released the first ν e appearance results. These data are of particular importance because they allow us to probe for the first time in a direct (or manifest) way the leptonic CP-violation. In fact, it is the first time that a hint of CP-violation arises from the comparison of the observations of neutrinos and antineutrinos. We consider the implications of such new results both for the standard 3-flavor framework and for the non-standard 3 + 1 scheme involving one sterile neutrino species. The 3-flavor analysis shows a consolidation of the previous trends, namely a slight preference for sin ⁡ δ < 0 , disfavoring CP conservation ( δ = 0 , π ) with a statistical significance close to 90 % C.L., and a mild preference (at more than 68% C.L.) for the normal hierarchy. In a 3 + 1 framework, the data constrain two CP-phases ( δ 13 ≡ δ and δ 14 ), which exhibit a slight preference for the common value δ 13 ≃ δ 14 ≃ − π / 2 . Interestingly, in the enlarged four neutrino scheme the preference for the normal hierarchy found within the 3-flavor framework completely disappears. This indicates that light sterile neutrinos may constitute a potential source of fragility in the capability of the two LBL experiments of discriminating the neutrino mass hierarchy. [ABSTRACT FROM AUTHOR]

We show that the Galactic latitude distribution of IceCube astrophysical neutrino events with energies above 100 TeV is inconsistent with the isotropic model of the astrophysical neutrino flux. Namely, the Galactic latitude distribution of the events shows an excess at low latitudes | b | < 10° and a deficit at high Galactic latitude | b | ≳50°. We use Monte–Carlo simulations to show that the inconsistency of the isotropic signal model with the data is at ≳3 σ level, after the account of trial factors related to the choice of the low-energy threshold and Galactic latitude binning in our analysis. [ABSTRACT FROM AUTHOR]

It has recently been shown that the phenomenologically successful pattern of cobimaximal neutrino mixing ( θ 13 ≠ 0 , θ 23 = π / 4 , and δ C P = ± π / 2 ) may be achieved in the context of the non-Abelian discrete symmetry A 4 . In this paper, the same goal is achieved with S 3 × Z 2 . The residual lepton Z 3 triality in the case of A 4 is replaced here by Z 2 × Z 2 . The associated phenomenology of the scalar sector is discussed. [ABSTRACT FROM AUTHOR]

The possibility of measuring neutral-current coherent elastic neutrino–nucleus scattering (CENNS) at the TEXONO experiment has opened high expectations towards probing exotic neutrino properties. Focusing on low threshold Germanium-based targets with kg-scale mass, we find a remarkable efficiency not only for detecting CENNS events due to the weak interaction, but also for probing novel electromagnetic neutrino interactions. Specifically, we demonstrate that such experiments are complementary in performing precision Standard Model tests as well as in shedding light on sub-leading effects due to neutrino magnetic moment and neutrino charge radius. This work employs realistic nuclear structure calculations based on the quasi-particle random phase approximation (QRPA) and takes into consideration the crucial quenching effect corrections. Such a treatment, in conjunction with a simple statistical analysis, shows that the attainable sensitivities are improved by one order of magnitude as compared to previous studies. [ABSTRACT FROM AUTHOR]

The Askaryan Radio Array (ARA) is an ultra-high energy ( > 10 17 eV) cosmic neutrino detector in phased construction near the south pole. ARA searches for radio Cherenkov emission from particle cascades induced by neutrino interactions in the ice using radio frequency antennas ( ∼ 150 - 800 MHz) deployed at a design depth of 200 m in the Antarctic ice. A prototype ARA Testbed station was deployed at ∼ 30 m depth in the 2010–2011 season and the first three full ARA stations were deployed in the 2011–2012 and 2012–2013 seasons. We present the first neutrino search with ARA using data taken in 2011 and 2012 with the ARA Testbed and the resulting constraints on the neutrino flux from 10 17 - 10 21 eV. [ABSTRACT FROM AUTHOR]

In this work, we use models constructed with the Eggleton code for stellar evolution, along with the photometric data of the super-rich globular cluster ω -Centauri (Sollima et al., 2004), to put a constraint on the magnetic dipole moment of neutrinos. We begin with a review of the idea proposed by Raffelt and Dearborn (1988), in which, as a consequence of a non-zero magnetic dipole moment, the tip-RGB luminosity of low mass stars gets increased over its standard value. First, we measure the dependence of the He-core mass and bolometric luminosity, at the tip-RGB, on the existing fits to characterize plasmon decay into neutrinos, namely those from Itoh et al. (1992), Haft et al. (1994), and the more recent results from Kantor and Gushakov (2007). Then, stating our definition of the tip-RGB, we revise multiple theoretical aspects: the consequences of non-standard neutrino emission on the internal structure of stellar models, its impact on the calibration of the Reimers mass-loss rate and later evolutionary phases and the influence of initial Helium abundance, metallicity, convection theory and opacities. Finally, we consider the specific case of ω -Cen. Using our tip-RGB models, and the bolometric correction obtained by the PHOENIX code for stellar atmospheres, to estimate the luminosity for canonical and non-standard evolution, also measuring the impact of the reported chemical spread in ω -Cen on our results. We find that the upper limit μ ν ≤ 2.2 × 10 - 12 μ B is already well constrained by observations. This result compares with the one obtained by Viaux et al. (2013), μ ν ≤ 2.6 × 10 - 12 μ B , from photometric study of the globular cluster M5. [ABSTRACT FROM AUTHOR]

Recent work has proposed that the interaction between ordinary matter and a stochastic gravitational background can lead to the decoherence of large aggregates of ordinary matter. In this work we point out that these arguments can be carried over to a stochastic neutrino background but with the Planck scale of the gravitational decoherence replaced by the weak scale. This implies that it might be possible to observe such neutrino induced decoherence on a small, microscopic system rather than a macroscopic system as is the case for gravitationally induced decoherence. In particular we suggest that neutrino decoherence could be linked with observed variations in the decay rates of certain nuclei. Finally we point out that this proposed neutrino induced decoherence can be considered the complement of the Mikheev–Smirnov–Wolfenstein (MSW) effect. [ABSTRACT FROM AUTHOR]

Recently, IceCube found evidence for a diffuse signal of astrophysical neutrinos in an energy range of ∼ 60 TeV to the PeV-scale [1] . The origin of those events, being a key to understanding the origin of cosmic rays, is still an unsolved question. So far, analyses have not succeeded to resolve the diffuse signal into point-like sources. Searches including a maximum-likelihood-ratio test, based on the reconstructed directions and energies of the detected down- and up-going neutrino candidates, were also performed on IceCube data leading to the exclusion of bright point sources. In this paper, we present two methods to search for faint neutrino point sources in three years of IceCube data, taken between 2008 and 2011. The first method is an autocorrelation test, applied separately to the northern and southern sky. The second method is a multipole analysis, which expands the measured data in the northern hemisphere into spherical harmonics and uses the resulting expansion coefficients to separate signal from background. With both methods, the results are consistent with the background expectation with a slightly more sparse spatial distribution, corresponding to an underfluctuation. Depending on the assumed number of sources, the resulting upper limit on the flux per source in the northern hemisphere for an E - 2 energy spectrum ranges from ∼ 1.5 · 10 - 8 GeV/cm 2 s −1 , in the case of one assumed source, to ∼ 4 · 10 - 10 GeV/cm 2 s −1 , in the case of 3500 assumed sources. [ABSTRACT FROM AUTHOR]

Donald Glaser, 1960 Nobel laureate in Physics, recently passed away (2013), as have many of his colleagues who were involved with the early development of bubble chambers at the University of Michigan. In this paper I will review those early years and the subsequent wide-spread application of active-target (AT) bubble chambers that dominated high-energy physics (HEP) research for over thirty years. Some of the related, but more modern nuclear tracking detectors being used in HEP, neutrino astrophysics and dark-matter searches also will be discussed. [ABSTRACT FROM AUTHOR]

In this paper, we present high-energy neutrino spectra from 21 Galactic supernova remnants (SNRs), derived from gamma-ray measurements in the GeV–TeV range. We find that only the strongest sources, i.e. G40.5-0.5 in the north and Vela Junior in the south could be detected as single point sources by IceCube or KM3NeT, respectively. For the first time, it is also possible to derive a diffuse signal by applying the observed correlation between gamma-ray emission and radio signal. Radio data from 234 supernova remnants listed in Green’s catalog are used to show that the total diffuse neutrino flux is approximately a factor of 2.5 higher compared to the sources that are resolved so far. We show that the signal at above 10 TeV energies can actually become comparable to the diffuse neutrino flux component from interactions in the interstellar medium. Recently, the IceCube collaboration announced the detection of a first diffuse signal of astrophysical high-energy neutrinos. Directional information cannot unambiguously reveal the nature of the sources at this point due to low statistics. A number of events come from close to the Galactic center and one of the main questions is whether at least a part of the signal can be of Galactic nature. In this paper, we show that the diffuse flux from well-resolved SNRs is at least a factor of 20 below the observed flux. [ABSTRACT FROM AUTHOR]

On the basis of a previously proposed mechanism of neutrino–antineutrino mass splitting in the Standard Model, which is Lorentz and SU ( 2 ) × U ( 1 ) invariant but non-local to evade the CPT theorem, we discuss the possible implications of neutrino–antineutrino mass splitting on neutrino physics and baryogenesis. It is shown that non-locality within a distance scale of the Planck length, that may not be fatal to unitarity in a generic effective theory, can generate the neutrino–antineutrino mass splitting of the order of the observed neutrino mass differences, which is tested in oscillation experiments, and a non-negligible baryon asymmetry depending on the estimate of sphaleron dynamics. The one-loop order induced electron–positron mass splitting in the Standard Model is shown to be finite and estimated at ∼ 10 − 20 eV , well below the experimental bound < 10 − 2 eV . The induced CPT violation in the K -meson in the Standard Model is expected to be even smaller and well below the experimental bound | m K − m K ¯ | < 0.44 × 10 − 18 GeV . [ABSTRACT FROM AUTHOR]

We describe a simple model that automatically generates the sum over gauge group representations and chiralities of a single generation of fermions in the Standard Model, augmented by a sterile neutrino. The model is a modification of the world-line approach to chiral fermions. [ABSTRACT FROM AUTHOR]

Atmospheric neutrinos are an important background to astrophysical neutrino searches, and are also of considerable interest in their own right. This paper points out that the contribution to conventional atmospheric ν e of the rare semileptonic decay of K S becomes significant at high energy. Although the K S → π e ν branching ratio is very small, the short K S lifetime leads to a high critical energy, so that, for vertical showers, the inclusion of K S semileptonic decay increases the conventional ν e flux by ≈ 30 % at energies above 100 TeV. In this paper, we present calculations of the flux of ν e from K S . At energies above their critical energies, the ν e fluxes from kaon decay may be simply related to the kaon semileptonic widths; this leads to a near-equality between the flux of ν e from K + , K L and K S . [ABSTRACT FROM AUTHOR]

In the process of supernova explosion the leakage of neutrinos is very important. Adopting an one-dimensional spherically symmetrical model, and under the different neutrino leakage modes, the explosion processes of type II supernovae with masses of 12 M ⊙ , 14 M ⊙ , and 15 M ⊙ are simulated numerically. The results indicate that all these different neutrino leakage modes have influences on the supernova collapse, shock propagation, and supernova explosion. The best values of the related parameters which are propitious for the type II supernova explosion are given. In addition, the impacts of the equation of state and the compression modulus on the simulated results are discussed. [ABSTRACT FROM AUTHOR]

This is a report on the status and prospects of the quantification of neutrino properties through the cosmological neutrino background for the Cosmic Frontier of the Division of Particles and Fields Community Summer Study long-term planning exercise. Experiments planned and underway are prepared to study the cosmological neutrino background in detail via its influence on distance-redshift relations and the growth of structure. The program for the next decade described in this document, including upcoming spectroscopic galaxy surveys eBOSS and DESI and a new Stage-IV CMB polarization experiment CMB-S4, will achieve σ ( σ m ν ) = 16 meV and σ ( N eff ) = 0.020. Such a mass measurement will produce a high significance detection of non-zero σ m ν , whose lower bound derived from atmospheric and solar neutrino oscillation data is about 58 meV. If neutrinos have a minimal normal mass hierarchy, this measurement will definitively rule out the inverted neutrino mass hierarchy, shedding light on one of the most puzzling aspects of the Standard Model of particle physics — the origin of mass. This precise a measurement of N eff will allow for high sensitivity to any light and dark degrees of freedom produced in the big bang and a precision test of the standard cosmological model prediction that N eff = 3.046 . [ABSTRACT FROM AUTHOR]

The Antarctic Ross Ice Shelf Antenna Neutrino Array (ARIANNA) is a high-energy neutrino detector designed to record the Askaryan electric field signature of cosmogenic neutrino interactions in ice. To understand the inherent radio-frequency (RF) neutrino signature, the time-domain response of the ARIANNA RF receiver must be measured. ARIANNA uses Create CLP5130-2N log-periodic dipole arrays (LPDAs). The associated effective height operator converts incident electric fields to voltage waveforms at the LDPA terminals. The effective height versus time and incident angle was measured, along with the associated response of the ARIANNA RF amplifier. The results are verified by correlating to field measurements in air and ice, using oscilloscopes. Finally, theoretical models for the Askaryan electric field are combined with the detector response to predict the neutrino signature. [ABSTRACT FROM AUTHOR]

Reactions ν l γ → W + l − ( l = e , μ , τ ) near the threshold s = m W + m l are analyzed. Two independent calculations of the corresponding cross sections (straightforward calculations using the Standard Electroweak Lagrangian and calculations in the framework of the parton model) are compared. It is shown that the Standard Electroweak Theory strongly suggests that these reactions proceed via the Glashow resonances. Accordingly, a hypothesis that the on-shell W bosons in the reactions ν l γ → W + l − are the Glashow resonances is put forward. A role of these reactions for testing T symmetry is discussed. A model with T-violating Glashow resonances for description of the distribution of the TeV–PeV neutrino events recently observed by the IceCube Collaboration is presented. [ABSTRACT FROM AUTHOR]

A search for Supernova Relic Neutrinos ...e's is first conducted via inverse-beta-decay by tagging neutron capture on hydrogen at Super-Kamiokande-IV. The neutron tagging efficiency is determined to be (17.74±0.04stat.±1.05sys.), while the corresponding accidental background probability is (1.06±0.01stat.±0.18sys.). Using 960 days of data, we obtain 13 inverse-beta-decay candidates in the range of ... between 13.3 MeV and 31.3 MeV. All of the observed candidates are attributed to background. Upper limits at 90% C.L. are calculated in the absence of a signal. [ABSTRACT FROM AUTHOR]

The IceCube detector is unique. It uses the Antarctic glacial ice as an interaction and detection medium. An array of optical sensors observes Cherenkov light from secondary charged particles resulting from neutrino interactions. The high transparency of the ice enabled the realization of a 1 km 3 large detection volume in order to detect rarely interacting particles. Neutrinos are ideal probes of the deep universe because they rarely interact with matter and propagate in straight lines. Neutrinos are thought to be produced in hadronic processes at astronomical sources such as active galactic nuclei and gamma-ray bursts. IceCube aims to detect neutrinos from such astronomical sources. IceCube recently found 28 events in an energy range approximately from 50 TeV to 1 PeV. These events are not easily explained by background derived from atmospheric origin, and therefore represent the first evidence for high energy neutrinos from an extraterrestrial origin. IceCube can also perform elementary particle physics by searching for neutrinos from SUSY particles such as neutralinos and measuring atmospheric neutrino oscillations. An overview of the latest IceCube results is provided in this paper including the 28 candidate observations and the corresponding implications. [ABSTRACT FROM AUTHOR]