Neutrinos In Coincidence Research Articles

SEARCH FOR NEUTRINOS IN SUPER-KAMIOKANDE ASSOCIATED WITH GRAVITATIONAL-WAVE EVENTS GW150914 AND GW151226

ABSTRACT We report the results from a search in Super-Kamiokande for neutrino signals coincident with the first detected gravitational-wave events, GW150914 and GW151226, as well as LVT151012, using a neutrino energy range from 3.5 MeV to 100 PeV. We searched for coincident neutrino events within a time window of ±500 s around the gravitational-wave detection time. Four neutrino candidates are found for GW150914, and no candidates are found for GW151226. The remaining neutrino candidates are consistent with the expected background events. We calculated the 90% confidence level upper limits on the combined neutrino fluence for both gravitational-wave events, which depends on event energy and topologies. Considering the upward-going muon data set (1.6 GeV–100 PeV), the neutrino fluence limit for each gravitational-wave event is 14–37 (19–50) cm−2 for muon neutrinos (muon antineutrinos), depending on the zenith angle of the event. In the other data sets, the combined fluence limits for both gravitational-wave events range from 2.4 × 104 to 7.0 × 109 cm−2.

Search for UHE neutrinos in coincidence with LIGO GW150914 event with the Pierre Auger Observatory

AbstractThe first gravitational wave transient GW150914 was observed by Advanced LIGO on September 14th, 2015 at 09:50:45 Universal Time. In addition to follow-up electromagnetic observations, the detection of neutrinos will probe deeply and more on the nature of astrophysical sources, especially in the ultra-high energy regime. Neutrinos in the EeV energy range were searched in data collected at the surface detector of the Pierre Auger Observatory within ± 500 s and 1 day after the GW150914 event. No neutrino candidates were found. Based on this non-observation, we derive the first and only neutrino fluence upper limit at EeV energies for this event at 90% CL, and report constraints on existence of accretion disk around mergers.

High-energy neutrino follow-up search of gravitational wave event GW150914 with ANTARES and IceCube

We present the high-energy-neutrino follow-up observations of the first gravitational wave transient GW150914 observed by the Advanced LIGO detectors on Sept. 14th, 2015. We search for coincident neutrino candidates within the data recorded by the IceCube and ANTARES neutrino detectors. A possible joint detection could be used in targeted electromagnetic follow-up observations, given the significantly better angular resolution of neutrino events compared to gravitational waves. We find no neutrino candidates in both temporal and spatial coincidence with the gravitational wave event. Within 500 s of the gravitational wave event, the number of neutrino candidates detected by IceCube and ANTARES were three and zero, respectively. This is consistent with the expected atmospheric background, and none of the neutrino candidates were directionally coincident with GW150914. We use this non-detection to constrain neutrino emission from the gravitational-wave event.

PROPAGATION AND NEUTRINO OSCILLATIONS IN THE BASE OF A HIGHLY MAGNETIZED GAMMA-RAY BURST FIREBALL FLOW

Neutrons play an important role in the dynamics of gamma-ray bursts. The presence of neutrons in the baryon-loaded fireball is expected. If the neutrons abundance is comparable to that of protons, important features may be observed such as quasi-thermal multi-GeV neutrinos in coincidence with a subphotospheric $\gamma$-ray emission, nucleosynthesis at later times and rebrightening of the afterglow emission. Additionally, thermal MeV neutrinos are created by electron-positron annihilation, electron (positron) capture on protons (neutrons) and nucleonic bremsstrahlung. Although MeV neutrinos are difficult to detect, quasi-thermal GeV neutrinos are expected in km$^3$ detectors and/or DeepCore+IceCube. In this paper, we show that neutrino oscillations have outstanding implications for the dynamics of the fireball evolution and also that they can be detected through their flavor ratio on Earth. For that we derive the resonance and charged-neutrality conditions as well as the neutrino self-energy and effective potential up to order $m_W^{-4}$ at strong, moderate and weak magnetic field approximation to constrain the dynamics of the fireball. We found important implications: i) resonant oscillations are suppressed for high baryon densities as well as neutrons abundance larger than that of protons and ii) the effect of magnetic field is to decrease the proton-to-neutron ratio aside from the number of multi-GeV neutrinos expected in DeepCore detector. Also we estimate the GeV neutrino flavor ratios along the jet and on Earth.

Neutrino astrophysics with IceCube

IceCube is a neutrino observatory in operation at the geographical South Pole. The main objective of IceCube is to conduct very-high-energy neutrino astronomy, including the search for the sources of cosmic rays. IceCube operates by measuring Cherenkov light from particles produced in neutrino–matter interactions. IceCube has made multiple observations including atmospheric neutrinos and cosmic ray anisotropy. For the first time, IceCube is reporting the observation of 28 events consistent with an astrophysical origin. The events have energies that range from ≈30TeV to ≈1.2PeV. The atmospheric origin of the events is excluded at the 4.1σlevel. In these proceedings we summarize the study of these 28 events. We also present the results of the search for neutrinos in coincidence with GRB 130427A.

Search for muon neutrinos from gamma-ray bursts with the ANTARES neutrino telescope using 2008 to 2011 data

A search for muon neutrinos in coincidence with gamma-ray bursts with the ANTARES neutrino detector using data from the end of 2007 to 2011 is performed. Expected neutrino fluxes are calculated for each burst individually. The most recent numerical calculations of the spectra using the NeuCosmA code are employed, which include Monte Carlo simulations of the full underlying photohadronic interaction processes. The discovery probability for a selection of 296 gamma-ray bursts in the given period is optimised using an extended maximum-likelihood strategy. No significant excess over background is found in the data, and 90% confidence level upper limits are placed on the total expected flux according to the model.

SEARCHES FOR HIGH-ENERGY NEUTRINO EMISSION IN THE GALAXY WITH THE COMBINED ICECUBE-AMANDA DETECTOR

We report on searches for neutrino sources at energies above 200 GeV in the Northern sky of the galactic plane, using the data collected by the South Pole neutrino telescopes IceCube and AMANDA. The galactic region considered here includes the Local Arm towards the Cygnus region and our closest approach to the Perseus Arm. The data have been collected between 2007 and 2009 when AMANDA was an integrated part of IceCube, which was still under construction and operated with 22-strings (2007-8) and 40-strings (2008-9) of optical modules deployed in the ice. By combining the larger IceCube detector with the lower energy threshold of the more compact AMANDA detector, we obtain an improved sensitivity at energies below $\sim$10 TeV with respect to previous searches. The analyses presented here are: a scan for point sources within the galactic plane; a search optimized for multiple and extended sources in the Cygnus region, which might be below the sensitivity of the point source scan; and studies of seven pre-selected neutrino source candidates. For one of them, Cygnus X-3, a time-dependent search for neutrinos in coincidence with observed radio and X-ray flares has been performed. No evidence of a signal is found, and upper limits are reported for each of the searches. We investigate neutrino spectra proportional to E$^{-2}$ and E$^{-3}$ to cover the entire range of possible spectra. The soft E$^{-3}$ spectrum results in an energy distribution similar to a source with cut-off below $\sim$50 TeV. For the considered region of the galactic plane, the 90% confidence level muon neutrino flux upper limits are in the range E$^3$dN/dE$\sim 5.4 - 19.5 \times 10^{-11} \rm{TeV^{2} cm^{-2} s^{-1}}$ for point-like neutrino sources in the energy region [180.0 GeV - 20.5 TeV]. These represent the most stringent upper limits for soft-spectra neutrino sources within the Galaxy reported to date.

KM3NeT: An underwater multi-km3 neutrino detector

The KM3NeT consortium is studying the main technological options for the construction of a research infrastructure in the Mediterranean Sea, hosting a neutrino telescope with an instrumented volume of several km3 and an integrated platform for earth and deep sea sciences. The telescope location will allow the survey of a large part of the Galactic plane, including the Galactic Centre, thus complementing the sky coverage of the IceCube telescope located at the South Pole. A telescope deployed in deep sea water is expected to have a very good angular resolution (of the order of 0.1° for neutrinos with 100TeV energy), providing high sensitivity to point-like sources. The realization of this project will provide the scientific community with a powerful instrument to study and constrain the acceleration mechanisms of some astrophysical objects, including supernova remnants, active galactic nuclei, gamma-ray bursters. Neutrino telescopes can also investigate some of the most fundamental questions on HE physics beyond the standard model, including: the nature of dark matter through the indirect search for WIMPs, the study of subdominant effects on neutrino oscillations, including those possibly induced by the violation of the Lorentz invariance; the study of relic particles (magnetic monopoles, nuclearites) in cosmic radiation, the coincident neutrino emission with gravitational waves.This challenging project will require the installation of thousands of photon detectors with their related electronics and calibration systems several kilometers below sea level. This contribution presents an outline of the technological aspects of the project and a discussion of its main physics goals and expected performances, with a proposed preliminary timeline towards the completion of this instrument.

The neutrino velocity anomaly as an explanation of the missing observation of neutrinos in coincidence with GRB

The search for neutrinos emitted in coincidence with Gamma-Bay Burst has been so far unsuccessfully. In this paper we show that the recent result reported by the OPERA Collaboration on an early arrival time of muon neutrinos with respect to the one computed assuming the speed of light in vacuum could explain the null search for neutrinos in coincidence with Gamma-Ray Burst. Conversely, the detection of neutrino would falsify (or severely constraint) the interpretation of the OPERA anomaly in terms of super-luminal neutrinos.

The NESTOR underwater neutrino telescope project

The NESTOR collaboration is continuing its efforts towards deploying an underwater neutrino telescope. Further site studies (e.g. water light transmission measurements, sedimentation rates, etc.) are being carried out within the context of characterizing a site that may host the proposed KM3NeT infrastructure. In addition, following the successful deployment of a single floor of a NESTOR tower in 2003, five floors are now in the final stages of preparation. The use of these five floors in a form of a truncated tower together with four autonomous strings to be located some 300 m away from the tower is being contemplated. This arrangement, named NuBE (for Neutrino Burst Experiment), that may allow the detection neutrinos in coincidence with Gamma Ray Bursts, will be described.

Searches for Neutrinos from Gamma Ray Bursts with AMANDA-II and IceCube

The hadronic fireball model predicts a neutrino flux in the TeV to several PeV range simultaneous with the prompt photon emission of GRBs. The discovery of high energy neutrinos in coincidence with a gamma ray burst would help confirm the role of GRBs as accelerators of high energy cosmic rays. We summarize the methods employed by the AMANDA experiment in the search for neutrinos from GRBs and present results from several analyses.

High energy neutrinos from gamma-ray bursts

Observations suggest that γ-ray bursts (GRBs) are produced by the dissipation of the kinetic energy of a relativistic fireball. In this talk, recent work on the production of high energy neutrinos by GRB fireballs is reviewed. A significant fraction of GRB energy is expected to be converted to an accompanying burst of high energy neutrinos. Photomeson interactions produce a burst of ∼ 100 TeV neutrinos in coincidence with the GRB, and a burst of ∼ 10 18 eV neutrinos following the GRB on a time scale of 10 s. Inelastic p− n nuclear collisions result in the production of a burst of ∼ 10 GeV neutrinos in coincidence with the GRB. Planned 1 km 3 neutrino telescopes are expected to detect tens of 100 TeV neutrino events, and several 10 18 eV events, correlated with GRBs per year. A suitably densely spaced detector may allow the detection of several 10 GeV events per year. The detection of high-energy neutrino events correlated with GRBs will allow to constrain GRB progenitor models and to test the suggestion that GRBs accelerate protons to ∼ 10 20 eV. Moreover, such detection will allow to test for neutrino properties, e.g. flavor oscillations (for which upward moving τ's would be a unique signature) and coupling to gravity, with an accuracy many orders of magnitude better than is currently possible.