Jet heating via nuclear collisions may be the main mechanism for gamma-ray burst (GRB) emission. Besides producing the observed gamma-rays, collisional heating must generate 10-100 GeV neutrinos, implying a close relation between the neutrino and gamma-ray luminosities. We exploit this theoretical relation to make predictions for possible GRB detections by IceCube+DeepCore. To estimate the expected neutrino signal, we use the largest sample of bursts observed by BATSE in 1991-2000. A GRB neutrino could have been detected if IceCube+DeepCore operated at that time. Detection of 10-100 GeV neutrinos would have significant implications, shedding light on the composition of GRB jets and their Lorentz factors. This could be an important target in designing future upgrades of the IceCube+DeepCore observatory.
The IceCube DeepCore is a dense infill array of the IceCube Neutrino Observatory at the South Pole. While IceCube is best suited for detecting neutrinos with energies of several 100 GeV and above, DeepCore allows to probe neutrinos with lower energies. We focus on a sample of neutrinos with energies above approximately 10 GeV, which was originally optimised for oscillation experiments. Recently, it has been adapted to enable searches for transient sources of astrophysical neutrinos in the sky. In particular, this low-energy dataset can be used to conduct follow-up searches of gravitational wav…
DeepCore, as a densely instrumented sub-detector of IceCube, extends IceCube's energy reach down to about 10 GeV, enabling the search for astrophysical transient sources, e.g., choked gamma-ray bursts. While many other past and on-going studies focus on triggered time-dependent analyses, we aim to utilize a newly developed event selection and dataset for an untriggered all-sky time-dependent search for transients. In this work, all-flavor neutrinos are used, where neutrino types are determined based on the topology of the events. We extend the previous DeepCore transient half-sky search to an …
The IceCube Neutrino Observatory is the world's largest high energy neutrino telescope, using the Antarctic ice cap as a Cherenkov detector medium. DeepCore, the low energy extension to IceCube, is an infill array with a fiducial volume of around 30 MTon in the deepest, clearest ice, aiming for an energy threshold as low as 10 GeV and extending IceCube's sensitivity to indirect dark matter searches and atmospheric neutrino oscillation physics. We will discuss the analysis of the first year of DeepCore data, as well as ideas for a further extension of the particle physics program in the ice wit…
New physics in neutrino sector can reveal itself via non-standard neutrino interactions which can result in modification of the standard picture of neutrino propagation in matter. Experiments with atmospheric neutrinos has been used to probe this scenario. Using publicly available three-year low energy data in IceCube DeepCore we place bounds on the parameters $ε_{αβ}$ of non-standard neutrino interactions in propagation. We obtain restrictive constraints not only for $μτ$ sector but also for flavor changing interactions involving electron neutrinos.
Dark matter decaying or annihilating into mu+mu- or tau+tau- has been proposed as an explanation for the e+e- anomalies reported by PAMELA and Fermi. Recent analyses show that IceCube, supplemented by DeepCore, will be able to significantly constrain the parameter space of decays to mu+mu-, and rule out decays to tau+tau- and annihilations to mu+mu- in less than five years of running. These analyses rely on measuring track-like events in IceCube+DeepCore from down-going nu_mu. In this paper we show that by instead measuring cascade events, which are induced by all neutrino flavors, IceCube+Dee…
IceCube-DeepCore is a compact Cherenkov detector located in the clear ice of the bottom center of the IceCube Neutrino Telescope. Its purpose is to enhance the sensitivity of IceCube for low neutrino energies (< 1 TeV) and to lower the detection threshold of IceCube by about an order of magnitude to below 10 GeV. The detector is formed by 6 additional strings of 360 high quantum efficiency phototubes together with the 7 central IceCube strings. The improved sensitivity will provide an enhanced sensitivity to probe a range of parameters of dark matter models not covered by direct experiments. I…
We show that study of the atmospheric neutrinos in the 10--100 GeV energy range by DeepCore sub-array of the IceCube Neutrino Observatory can substantially constrain the mixing of sterile neutrinos of mass $\sim 1$ eV with active neutrinos. In the scheme with one sterile neutrino we calculate $ν_μ-$ and $\barν_μ-$ oscillation probabilities as well as zenith angle distributions of $ν_μ^{CC}$ events in different energy intervals in DeepCore. The distributions depend on the mass hierarchy of active neutrinos. Therefore, in principle, the hierarchy can be identified, if $ν_s$ exists. After a few y…
The IceCube Neutrino Detector observes tens of thousands of atmospheric neutrinos every year with its low energy extension DeepCore, covering the neutrino energy range from GeV to TeV. These neutrinos can be used to study particle interactions in conditions that are inaccessible to current accelerator-based experiments. Here, we present constraints concerning the production of light and strange mesons in atmospheric particle cascades using a dedicated analysis based on the shape of the neutrino spectrum in zenith and energy. We report the first measurement of the atmospheric K/Pi-ratio in a co…
The deployment of DeepCore array significantly lowers IceCube's energy threshold to about 10 GeV and enhances the sensitivity of detecting neutrinos from annihilations and decays of light dark matter. To match this experimental development, we calculate the track event rate in DeepCore array due to neutrino flux produced by annihilations and decays of galactic dark matter. We also calculate the background event rate due to atmospheric neutrino flux for evaluating the sensitivity of DeepCore array to galactic dark matter signatures. Unlike previous approaches, which set the energy threshold for…
An unfolding measurement of the atmospheric neutrino flux at the South Pole is performed using the IceCube/DeepCore detector. The main results presented is the true neutrino interaction rate by unit volume of ice, as a function of energy or zenith angle. The method used is the D'Agostini iterative unfolding. While the detector response estimate is based on Monte Carlo simulation, the iterative approach will compensate for this inherent bias and draw the unfolded result closer to the unbiased estimator, as the number of iterations is optimized. This is done using an ensemble test with a blind r…
We investigate the prospects for indirect detection of fermion WIMPless dark matter at the neutrino telescopes IceCube and DeepCore. The dark matter annihilating in the Sun is a hidden sector Majorana fermion that couples through Yukawa couplings to a connector particle and a visible sector particle, and it exhibits only spin-dependent scattering with nuclei via couplings to first generation quarks. We consider cases where the annihilation products are taus, staus, or sneutrinos of the three generations. To evaluate the muon fluxes incident at the detector, we propagate the neutrino spectra th…
With the augmentation of IceCube by DeepCore, the prospect for detecting dark matter annihilation in the Sun is much improved. To complement this experimental development, we provide a thorough template analysis of the particle physics issues that are necessary to precisely interpret the data. Our study is about nitty-gritty and is intended as a framework for detailed work on a variety of dark matter candidates. To accurately predict the source neutrino spectrum, we account for spin correlations of the final state particles and the helicity-dependence of their decays, and absorption effects at…
Neutrinos with energies ranging from GeV to sub-TeV are expected to be produced in Gamma-Ray Bursts (GRBs) as a result of the dissipation of the jet kinetic energy through nuclear collisions occurring around or below the photosphere, where the jet is still optically thick to high-energy radiation. So far, the neutrino emission from the inelastic collisional model in GRBs has been poorly investigated from the experimental point of view. In the present work, we discuss prospects for identifying neutrinos produced in such collisionally heated GRBs with the large volume neutrino telescopes KM3NeT …
Cosmological and astrophysical observations provide increasing evidence of the existence of dark matter in our Universe. Dark matter particles with a mass above a few GeV can be captured by the Sun, accumulate in the core, annihilate, and produce high energy neutrinos either directly or by subsequent decays of Standard Model particles. We investigate the prospects for indirect dark matter detection in the IceCube/DeepCore neutrino telescope and its capabilities to determine the dark matter mass.
Atmospheric neutrino oscillations with DeepCore; Supernova detection with IceCube and beyond; Study of South Pole ice transparency with IceCube flashers; Submitted papers to the 32nd International Cosmic Ray Conference, Beijing 2011.
We present the results of an analysis of data collected by IceCube/DeepCore in 2010-2011 resulting in the first significant detection of neutrino oscillations in a high-energy neutrino telescope. A low-energy muon neutrino sample (20-100 GeV) containing the oscillation signal was extracted from data collected by DeepCore. A high-energy muon neutrino sample (100 GeV -10 TeV) was extracted from IceCube data in order to constrain the systematic uncertainties. The non-oscillation hypothesis was rejected with more than $5σ$. We fitted the oscillation parameters $Δm^2_{23}$ and $\sin^22 θ_{23}$ to t…
The IceCube Neutrino Observatory, completed in December 2010 and located at the geographic South Pole, is the largest neutrino telescope in the world. IceCube includes the more densely instrumented DeepCore subarray, which increases IceCube's sensitivity at neutrino energies down to 10 GeV. DeepCore has recently demonstrated sensitivity to muon neutrino disappearance from atmospheric neutrino oscillation. A further extension is under consideration, the Precision IceCube Next Generation Upgrade (PINGU) which would lower the energy threshold below about 10 GeV. In particular, PINGU would be sens…
We present the first statistically significant detection of neutrino oscillations in the high-energy regime ($>$ 20 GeV) from an analysis of IceCube Neutrino Observatory data collected in 2010-2011. This measurement is made possible by the low energy threshold of the DeepCore detector ($\sim 20$ GeV) and benefits from the use of the IceCube detector as a veto against cosmic ray-induced muon background. The oscillation signal was detected within a low-energy muon neutrino sample (20 -- 100 GeV) extracted from data collected by DeepCore. A high-energy muon neutrino sample (100 GeV -- 10 TeV) was…
Recent observations of GeV gamma-rays from novae have led to a paradigm shift in the understanding of these objects. While it is now believed that shocks contribute significantly to the energy budget of novae, it is still unknown if the emission is hadronic or leptonic in origin. Neutrinos could hold the key to definitively differentiating between these two scenarios, though the energies of such particles would be much lower than are typically targeted with neutrino telescopes. IceCube's densely instrumented DeepCore sub-array provides the ability to reduce the threshold for observation from 1…
Neutrino production and oscillation physics can be studied by utilizing the very high flux of atmospheric neutrinos observed with IceCube. In a Cherenkov medium such as ice, atmospheric muon neutrino interactions create tracks while cascades (showers) are produced by atmospheric electron neutrinos and by neutral current interactions of all flavors. We present the first detection of atmospheric neutrino-induced cascades at energies between 30 GeV and 10 TeV using the DeepCore array of the IceCube detector. Using 281 days of data, 1029 events are observed with 59% predicted to be cascades.
The atmospheric neutrino data collected by the IceCube experiment and its low-energy extension DeepCore provide a unique opportunity to probe the neutrino sector of the Standard Model. In the low energy range the experiment have observed neutrino oscillations, and the high energy data are especially sensitive to signatures of new physics in the neutrino sector. In this context, we previously demonstrated the unmatched potential of the experiment to reveal the existence of light sterile neutrinos. The studies are routinely performed in the simplest 3+1 model concentrating on disappearance of mu…
Since the end of the eighties and in response to a reported increase in the total neutrino flux in the Homestake experiment in coincidence with a solar flare, solar neutrino detectors have searched for solar flare signals. Neutrinos from the decay of mesons, which are themselves produced in collisions of accelerated protons with the solar atmosphere, would provide a novel window on the underlying physics of the acceleration process. For our studies we focus on the IceCube Neutrino Observatory, a cubic kilometer neutrino detector located at the geographical South Pole. Due to its Supernova data…
Understanding cosmic acceleration mechanisms, such as jet formation in black holes, star collapses or binary mergers, and the propagation of accelerated particles in the universe is still a `work in progress' and requires a multi-messenger approach, exploiting the complementarities across all possible probes: ultra-high energy cosmic rays (UHECR), gamma-rays and neutrinos. In this report I will summarize some of the IceCube results concerning searches for astrophysical neutrino point sources and diffuse fluxes from populations of sources widely distributed in the sky or from the interactions o…
The IceCube detector, located at the South Pole, is discussed as a detector for core collapse supernovae. The large flux of $\barν_{e}$ from a Galactic supernova gives rise to Cherenkov light from positrons and electrons created in neutrino interactions which increase the overall count rate of the photomultipliers significantly. We will give an overview of the standard, count rate based, method for supernova detection and present the development of a novel technique. This technique uses coincident hits to extract additional information such as the average energy and spectral features. The pote…
Decaying dark matter has previously been proposed as a possible explanation for the excess high energy cosmic ray electrons and positrons seen by PAMELA and the Fermi Gamma-Ray Space Telescope (FGST). To accommodate these signals however, the decays must be predominantly leptonic, to muons or taus, and therefore produce neutrinos, potentially detectable with the IceCube neutrino observatory. We find that, with five years of data, IceCube (supplemented by DeepCore) will be able to significantly constrain the relevant parameter space of decaying dark matter, and may even be capable of discoverin…
It has been proposed that the gamma ray burst - supernova connection may manifest itself in a significant fraction of core collapse supernovae possessing mildly relativistic jets that do not break out of the stellar envelope. Neutrinos would provide proof of the existence of these jets. In the present letter we calculate the event rate of ~100 GeV neutrino-induced cascades in km^3 detectors. We also calculate the event rate for ~10 GeV neutrinos of all flavors with the DeepCore low energy extension of IceCube. The added event rate significantly improves the ability of km^3 detectors to search …
The IceCube Neutrino Observatory observes neutrinos interacting deep within the South Pole ice. It consists of 5,160 digital optical modules embedded within a cubic kilometer of ice, over depths of 1,450 m to 2,450 m. At the lower center of the array is the DeepCore subdetector. Its denser sensor configuration lowers the observable energy threshold to the GeV-scale, facilitating the study of atmospheric neutrino oscillations. The precise reconstruction of neutrino direction is critical in the measurements of oscillation parameters. This work presents a method to reconstruct the zenith angle of…
Archival Search for IceCube Sub-TeV Neutrino Counterparts to Sub-Threshold Gravitational Wave Events from the Third Observing Run of the LIGO-Virgo-KAGRA
Weakly Interacting Massive Particles (WIMPs) are well-motivated candidates for Dark Matter (DM). WIMP models often include self-annihilation into Standard Model particles such as neutrinos which could potentially be detected by the IceCube Neutrino Observatory. Various searches for a dark matter induced signal have been performed with the existing IceCube detector. However, since there is so far no evidence for WIMPs at TeV scales, more attention is brought to DM candidates at GeV masses, for which the IceCube detector is not sensitive due to its energy threshold. The IceCube collaboration is …
We present the results of a search for astrophysical sources of brief transient neutrino emission using IceCube and DeepCore data acquired between May 15th 2012 and April 30th 2013. While the search methods employed in this analysis are similar to those used in previous IceCube point source searches, the data set being examined consists of a sample of predominantly sub-TeV muon neu- trinos from the Northern Sky (-5$^{\circ}$ < δ < 90$^{\circ}$ ) obtained through a novel event selection method. This search represents a first attempt by IceCube to identify astrophysical neutrino sources in this …
Measurements of neutrinos at and below 10 GeV provide unique constraints of neutrino oscillation parameters as well as probes of potential Non-Standard Interactions (NSI). The IceCube Neutrino Observatory's DeepCore array is designed to detect neutrinos down to GeV energies. IceCube has built the world's largest data set of neutrinos >10 GeV, making searches for NSI a computational challenge. This work describes the use of convolutional neural networks (CNNs) to improve the energy reconstruction resolution and speed of reconstructing O(10 GeV) neutrino events in IceCube. Compared to current li…
The IceCube Neutrino Observatory, located under 1.4 km of Antarctic ice, instruments a cubic kilometer of ice with 5,160 optical modules that detect Cherenkov radiation originating from neutrino interactions. The more densely instrumented center, DeepCore, aims to detect atmospheric neutrinos at 10-GeV scales to improve important measurements of fundamental neutrino properties such as the oscillation parameters and to search for non-standard interactions. Sensitivity to oscillation parameters, dependent on the distance traveled over the neutrino energy (L/E), is limited in IceCube by the resol…
We present the first IceCube search for a signal of dark matter annihilations in the Milky Way using all-flavour neutrino-induced particle cascades. The analysis focuses on the DeepCore sub-detector of IceCube, and uses the surrounding IceCube strings as a veto region in order to select starting events in the DeepCore volume. We use 329 live-days of data from IceCube operating in its 86-string configuration during 2011-2012. No neutrino excess is found, the final result being compatible with the background-only hypothesis. From this null result, we derive upper limits on the velocity-averaged …
Since the discovery of a flux of high-energy astrophysical neutrinos, searches for their origins have focused primarily at TeV-PeV energies. Compared to sub-TeV searches, high-energy searches benefit from an increase in the neutrino cross section, improved angular resolution on the neutrino direction, and a reduced background from atmospheric neutrinos and muons. However, the focus on high energy does not preclude the existence of sub-TeV neutrino emission where IceCube retains sensitivity. Here we present the first all-flavor search from IceCube for transient emission of low-energy neutrinos,…
In models with one universal extra dimension (UED), the first Kaluza-Klein excitations of the hypercharge gauge boson, B^(1), and the neutral component of isospin gauge boson, W^3(1), are each viable dark matter candidates. In either case, such particles are predicted to accumulate in the core of the Sun, where they annihilate to generate a potentially observable flux of high energy neutrinos. In this article, we calculate the flux of neutrinos produced in this model and determine the constraints that can be placed on the UED parameter space from current IceCube data. For the case of B^(1) dar…
Time-Integrated Searches for Sub-TeV Neutrino Sources with IceCube-DeepCore
Loyola University Chicago（芝加哥洛约拉大学）；Deutsches Elektronen-Synchrotron DESY（德国电子同步加速器）；University of Canterbury（坎特伯雷大学）；Université Libre de Bruxelles（布鲁塞尔自由大学）；Niels Bohr Institute, University of Copenhagen（哥本哈根大学尼尔斯·玻尔研究所）；TU Dortmund University（多特蒙德工业大学）；University of Kansas（堪萨斯大学）；Bartol Research Institute and Dept. of Physics and Astronomy, University of Delaware（特拉华大学巴托尔研究所及物理与天文学系）；Marquette University（马凯特大学）；Harvard Universit（哈佛大学）
We study in detail the ability of the nominal configuration of the IceCube neutrino telescope (with 80 strings) to probe the parameter space of the Constrained MSSM (CMSSM) favoured by current collider and cosmological data. Adopting conservative assumptions about the galactic halo model and the expected experiment performance, we find that IceCube has a probability between 2% and 12% of achieving a 5sigma detection of dark matter annihilation in the Sun, depending on the choice of priors for the scalar and gaugino masses and on the astrophysical assumptions. We identify the most important ann…
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 $γ$-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 diff…
Galaxy clusters are one of the most promising candidate sites for dark matter annihilation. We focus on dark matter with mass in the range 10 GeV - 100 TeV annihilating to muon pairs, neutrino pairs, top pairs, or two neutrino pairs, and forecast the expected sensitivity to the annihilation cross section into these channels by observing galaxy clusters at IceCube/KM3NeT. Optimistically, the presence of dark matter substructures in galaxy clusters is predicted to enhance the signal by 2-3 orders of magnitude over the contribution from the smooth component of the dark matter distribution. Optimi…
Search for GeV-scale Dark Matter from the Galactic Center with IceCube-DeepCore
Loyola University Chicago（洛约拉大学芝加哥分校）；Deutsches Elektronen-Synchrotron DESY（德国电子同步加速器）；University of Canterbury（坎特伯雷大学）；Institute of Physics, Sachivalaya Marg, Sainik School Post, Bhubaneswar（萨奇瓦亚马格物理研究所（圣堂学校后，布巴内斯瓦尔））；Dept. of Physics and Wisconsin IceCube Particle Astrophysics Center, University of Wisconsin—Madison（威斯康星大学麦迪逊分校物理系与威斯康星冰立方粒子天体物理中心）；Université Libre de Bruxelles（布鲁塞尔自由大学）；Niels Bohr Institute, University of Copenhagen（哥本哈根大学尼尔斯玻尔研究所）；TU Dortmund University（多特蒙德工业大学）；University of Kansas（堪萨斯大学）；Bartol Research Institute and Dept. of Physics and Astronomy, University of Delaware（特拉华大学巴托尔研究所及物理与天文系）；Marquette University（马凯特大学）；Department of Physics and Laboratory for Particle Physics and Cosmology, Harvard University（哈佛大学物理系与粒子物理和宇宙学实验室）；University of Utah（犹他大学）
Relativistic outflows with neutrons inevitably lead to inelastic collisions, and resulting subphotospheric gamma rays may explain prompt emission of gamma-ray bursts. In this model, hadronuclear, quasithermal neutrinos in the 10-100 GeV range should be generated, and they may even have a high-energy tail by neutron-proton-converter or shock acceleration mechanisms. We demonstrate the importance of dedicated searches with DeepCore+IceCube, though such analyses have not been performed. Successful detections enable us to discriminate among prompt emission mechanisms, probe the jet composition, an…
We consider both velocity-dependent and velocity-independent contributions to spin-dependent (SD) and spin-independent (SI) nuclear scattering (including one-loop corrections) of WIMPless dark matter, in the case where the dark matter candidate is a Majorana fermion. We find that spin-independent scattering arises only from the mixing of exotic squarks, or from velocity-dependent terms. Nevertheless (and contrary to the case of MSSM neutralino WIMPs), we find a class of models which cannot be detected through SI scattering, but can be detected at IceCube/DeepCore through SD scattering. We stud…
