Showing papers by "Hermann Kolanoski published in 2020"
Book•
23 Feb 2020
TL;DR: The ATLAS detector as installed in its experimental cavern at point 1 at CERN is described in this paper, where a brief overview of the expected performance of the detector when the Large Hadron Collider begins operation is also presented.
Abstract: The ATLAS detector as installed in its experimental cavern at point 1 at CERN is described in this paper. A brief overview of the expected performance of the detector when the Large Hadron Collider begins operation is also presented.
3,111 citations
TL;DR: The results, all based on searches for a cumulative neutrino signal integrated over the 10 years of available data, motivate further study of these and similar sources, including time-dependent analyses, multimessenger correlations, and the possibility of stronger evidence with coming upgrades to the detector.
Abstract: This Letter presents the results from pointlike neutrino source searches using ten years of IceCube data collected between April 6, 2008 and July 10, 2018. We evaluate the significance of an astrophysical signal from a pointlike source looking for an excess of clustered neutrino events with energies typically above ∼1 TeV among the background of atmospheric muons and neutrinos. We perform a full-sky scan, a search within a selected source catalog, a catalog population study, and three stacked Galactic catalog searches. The most significant point in the northern hemisphere from scanning the sky is coincident with the Seyfert II galaxy NGC 1068, which was included in the source catalog search. The excess at the coordinates of NGC 1068 is inconsistent with background expectations at the level of 2.9σ after accounting for statistical trials from the entire catalog. The combination of this result along with excesses observed at the coordinates of three other sources, including TXS 0506+056, suggests that, collectively, correlations with sources in the northern catalog are inconsistent with background at 3.3σ significance. The southern catalog is consistent with background. These results, all based on searches for a cumulative neutrino signal integrated over the 10 years of available data, motivate further study of these and similar sources, including time-dependent analyses, multimessenger correlations, and the possibility of stronger evidence with coming upgrades to the detector.
222 citations
TL;DR: In this paper, the authors present an overview of a next-generation instrument, IceCube-Gen2, which will sharpen our understanding of the processes and environments that govern the universe at the highest energies.
Abstract: The observation of electromagnetic radiation from radio to $\gamma$-ray wavelengths has provided a wealth of information about the universe. However, at PeV (10$^{15}$ eV) energies and above, most of the universe is impenetrable to photons. New messengers, namely cosmic neutrinos, are needed to explore the most extreme environments of the universe where black holes, neutron stars, and stellar explosions transform gravitational energy into non-thermal cosmic rays. The discovery of cosmic neutrinos with IceCube has opened this new window on the universe. In this white paper, we present an overview of a next-generation instrument, IceCube-Gen2, which will sharpen our understanding of the processes and environments that govern the universe at the highest energies. IceCube-Gen2 is designed to: 1) Resolve the high-energy neutrino sky from TeV to EeV energies; 2) Investigate cosmic particle acceleration through multi-messenger observations; 3) Reveal the sources and propagation of the highest energy particles in the universe; 4) Probe fundamental physics with high-energy neutrinos. IceCube-Gen2 will increase the annual rate of observed cosmic neutrinos by a factor of ten compared to IceCube, and will be able to detect sources five times fainter than its predecessor. Furthermore, through the addition of a radio array, IceCube-Gen2 will extend the energy range by several orders of magnitude compared to IceCube. Construction will take 8 years and cost about \$350M. The goal is to have IceCube-Gen2 fully operational by 2033. IceCube-Gen2 will play an essential role in shaping the new era of multi-messenger astronomy, fundamentally advancing our knowledge of the high-energy universe. This challenging mission can be fully addressed only in concert with the new survey instruments across the electromagnetic spectrum and gravitational wave detectors which will be available in the coming years.
210 citations
TL;DR: This analysis provides the most detailed characterization of the neutrino flux at energies below ∼100 TeV compared to previous IceCube results, and suggests the existence of astrophysical neutrinos sources characterized by dense environments which are opaque to gamma rays.
Abstract: We report on the first measurement of the astrophysical neutrino flux using particle showers (cascades) in IceCube data from 2010-2015. Assuming standard oscillations, the astrophysical neutrinos in this dedicated cascade sample are dominated (∼90%) by electron and tau flavors. The flux, observed in the sensitive energy range from 16 TeV to 2.6 PeV, is consistent with a single power-law model as expected from Fermi-type acceleration of high energy particles at astrophysical sources. We find the flux spectral index to be γ=2.53±0.07 and a flux normalization for each neutrino flavor of ϕ_{astro}=1.66_{-0.27}^{+0.25} at E_{0}=100 TeV, in agreement with IceCube's complementary muon neutrino results and with all-neutrino flavor fit results. In the measured energy range we reject spectral indices γ≤2.28 at ≥3σ significance level. Because of high neutrino energy resolution and low atmospheric neutrino backgrounds, this analysis provides the most detailed characterization of the neutrino flux at energies below ∼100 TeV compared to previous IceCube results. Results from fits assuming more complex neutrino flux models suggest a flux softening at high energies and a flux hardening at low energies (p value ≥0.06). The sizable and smooth flux measured below ∼100 TeV remains a puzzle. In order to not violate the isotropic diffuse gamma-ray background as measured by the Fermi Large Area Telescope, it suggests the existence of astrophysical neutrino sources characterized by dense environments which are opaque to gamma rays.
163 citations
TL;DR: The results of a 3+1 sterile neutrino search using eight years of data from the IceCube Neutrino Observatory are presented and the best-fit point is found to be at sin-2(2θ_{24})=0.10 and Δm_{41}^{2}=4.5 eV^{2), which is consistent with the no sterile neutRino hypothesis.
Abstract: The results of a 3 + 1 sterile neutrino search using eight years of data from the IceCube Neutrino Observatory are presented. A total of 305 735 muon neutrino events are analyzed in reconstructed e ...
73 citations
TL;DR: In this paper, searches for eV-scale sterile neutrinos, in the context of a 3 + 1 model, using eight years of data from the IceCube Neutrino Telescope, were reported.
Abstract: We report in detail on searches for eV-scale sterile neutrinos, in the context of a 3 + 1 model, using eight years of data from the IceCube Neutrino Telescope. By analyzing the reconstructed energi ...
59 citations
TL;DR: In this article, the authors search for high-energy neutrino emission coincident with compact binary mergers observed by the LIGO and Virgo gravitational wave (GW) detectors during their first and second observing runs.
Abstract: Using the IceCube Neutrino Observatory, we search for high-energy neutrino emission coincident with compact binary mergers observed by the LIGO and Virgo gravitational wave (GW) detectors during their first and second observing runs. We present results from two searches targeting emission coincident with the sky localization of each gravitational wave event within a 1000 second time window centered around the reported merger time. One search uses a model-independent unbinned maximum likelihood analysis, which uses neutrino data from IceCube to search for point-like neutrino sources consistent with the sky localization of GW events. The other uses the Low-Latency Algorithm for Multi-messenger Astrophysics, which incorporates astrophysical priors through a Bayesian framework and includes LIGO-Virgo detector characteristics to determine the association between the GW source and the neutrinos. No significant neutrino coincidence is seen by either search during the first two observing runs of the LIGO-Virgo detectors. We set upper limits on the time-integrated neutrino emission within the 1000 second window for each of the 11 GW events. These limits range from 0.02-0.7 $\mathrm{GeV~cm^{-2}}$. We also set limits on the total isotropic equivalent energy, $E_{\mathrm{iso}}$, emitted in high-energy neutrinos by each GW event. These limits range from 1.7 $\times$ 10$^{51}$ - 1.8 $\times$ 10$^{55}$ erg. We conclude with an outlook for LIGO-Virgo observing run O3, during which both analyses are running in real time.
31 citations
TL;DR: In this paper, the authors test the hypothesis that these events are astrophysical in origin, possibly caused by a point source in the reconstructed direction, and show that an astrophysical explanation of these anomalous events under standard model assumptions is severely constrained regardless of source spectrum.
Abstract: During the first three flights of the Antarctic Impulsive Transient Antenna (ANITA) experiment, the collaboration detected several neutrino candidates. Two of these candidate events were consistent with an ultra-high-energy up-going air shower and compatible with a tau neutrino interpretation. A third neutrino candidate event was detected in a search for Askaryan radiation in the Antarctic ice, although it is also consistent with the background expectation. The inferred emergence angle of the first two events is in tension with IceCube and ANITA limits on isotropic cosmogenic neutrino fluxes. Here, we test the hypothesis that these events are astrophysical in origin, possibly caused by a point source in the reconstructed direction. Given that any ultra-high-energy tau neutrino flux traversing the Earth should be accompanied by a secondary flux in the TeV-PeV range, we search for these secondary counterparts in seven years of IceCube data using three complementary approaches. In the absence of any significant detection, we set upper limits on the neutrino flux from potential point sources. We compare these limits to ANITA's sensitivity in the same direction and show that an astrophysical explanation of these anomalous events under standard model assumptions is severely constrained regardless of source spectrum.
26 citations
TL;DR: Aartsen et al. as mentioned in this paper used a model-independent unbinned maximum-likelihood analysis to search for high-energy neutrino emission coincident with compact binary mergers observed by the LIGO and Virgo gravitational-wave (GW) detectors.
Abstract: Author(s): Aartsen, MG; Ackermann, M; Adams, J; Aguilar, JA; Ahlers, M; Ahrens, M; Alispach, C; Andeen, K; Anderson, T; Ansseau, I; Anton, G; Arguelles, C; Auffenberg, J; Axani, S; Bagherpour, H; Bai, X; Balagopal, AV; Barbano, A; Bartos, I; Barwick, SW; Bastian, B; Baum, V; Baur, S; Bay, R; Beatty, JJ; Becker, KH; Tjus, JB; Benzvi, S; Berley, D; Bernardini, E; Besson, DZ; Binder, G; Bindig, D; Blaufuss, E; Blot, S; Bohm, C; Boser, S; Botner, O; Bottcher, J; Bourbeau, E; Bourbeau, J; Bradascio, F; Braun, J; Bron, S; Brostean-Kaiser, J; Burgman, A; Buscher, J; Busse, RS; Carver, T; Chen, C; Cheung, E; Chirkin, D; Choi, S; Clark, BA; Clark, K; Classen, L; Coleman, A; Collin, GH; Conrad, JM; Coppin, P; Corley, KR; Correa, P; Countryman, S; Cowen, DF; Cross, R; Dave, P; De Clercq, C; Delaunay, JJ; Dembinski, H; Deoskar, K; De Ridder, S; Desiati, P; De Vries, KD; De Wasseige, G; De With, M; Deyoung, T; Diaz, A; Diaz-Velez, JC; Dujmovic, H; Dunkman, M; Dvorak, E; Eberhardt, B; Ehrhardt, T; Eller, P; Engel, R | Abstract: Using the IceCube Neutrino Observatory, we search for high-energy neutrino emission coincident with compact binary mergers observed by the LIGO and Virgo gravitational-wave (GW) detectors during their first and second observing runs. We present results from two searches targeting emission coincident with the sky localization of each GW event within a 1000 s time window centered around the reported merger time. One search uses a model-independent unbinned maximum-likelihood analysis, which uses neutrino data from IceCube to search for pointlike neutrino sources consistent with the sky localization of GW events. The other uses the Low-Latency Algorithm for Multi-messenger Astrophysics, which incorporates astrophysical priors through a Bayesian framework and includes LIGO-Virgo detector characteristics to determine the association between the GW source and the neutrinos. No significant neutrino coincidence is seen by either search during the first two observing runs of the LIGO-Virgo detectors. We set upper limits on the time-integrated neutrino emission within the 1000 s window for each of the 11 GW events. These limits range from 0.02 to 0.7 GeV cm-2. We also set limits on the total isotropic equivalent energy, E iso, emitted in high-energy neutrinos by each GW event. These limits range from 1.7 × 1051 to 1.8 × 1055 erg. We conclude with an outlook for LIGO-Virgo observing run O3, during which both analyses are running in real time.
26 citations
TL;DR: In this paper, the authors used 9.5 years of all-sky IceCube data to search for neutrino emission from 35 PWNe that are high-energy gamma-ray emitters.
Abstract: Pulsar wind nebulae (PWNe) are the main gamma-ray emitters in the Galactic plane. They are diffuse nebulae that emit nonthermal radiation. Pulsar winds, relativistic magnetized outflows from the central star, shocked in the ambient medium produce a multiwavelength emission from the radio through gamma-rays. Although the leptonic scenario is able to explain most PWNe emission, a hadronic contribution cannot be excluded. A possible hadronic contribution to the high-energy gamma-ray emission inevitably leads to the production of neutrinos. Using 9.5 yr of all-sky IceCube data, we report results from a stacking analysis to search for neutrino emission from 35 PWNe that are high-energy gamma-ray emitters. In the absence of any significant correlation, we set upper limits on the total neutrino emission from those PWNe and constraints on hadronic spectral components.
24 citations
Posted Content•
TL;DR: In this article, the results of a search for astrophysical tau neutrinos in 7.5 years of IceCube's high-energy starting event data were presented, and the first detection of two such events, with probabilities of approximately 76% and 98% of being produced by astrophysical TUs were reported.
Abstract: We present the results of a search for astrophysical tau neutrinos in 7.5 years of IceCube's high-energy starting event data. At high energies, two energy depositions stemming from the tau neutrino charged-current interaction and subsequent tau lepton decay may be resolved. We report the first detection of two such events, with probabilities of $\sim 76\%$ and $\sim 98\%$ of being produced by astrophysical tau neutrinos. The resultant astrophysical neutrino flavor measurement is consistent with expectations, disfavoring a no-astrophysical tau neutrino flux scenario with 2.8$\sigma$ significance.
TL;DR: In this paper, the authors test the hypothesis that these events are astrophysical in origin, possibly caused by a point source in the reconstructed direction, and show that an astrophysical explanation of these anomalous events under standard model assumptions is severely constrained regardless of source spectrum.
Abstract: During the first three flights of the Antarctic Impulsive Transient Antenna (ANITA) experiment, the collaboration detected several neutrino candidates. Two of these candidate events were consistent with an ultra-high-energy upgoing air shower and compatible with a tau neutrino interpretation. A third neutrino candidate event was detected in a search for Askaryan radiation in the Antarctic ice, although it is also consistent with the background expectation. The inferred emergence angle of the first two events is in tension with IceCube and ANITA limits on isotropic cosmogenic neutrino fluxes. Here we test the hypothesis that these events are astrophysical in origin, possibly caused by a point source in the reconstructed direction. Given that any ultra-high-energy tau neutrino flux traversing the Earth should be accompanied by a secondary flux in the TeV-PeV range, we search for these secondary counterparts in 7 yr of IceCube data using three complementary approaches. In the absence of any significant detection, we set upper limits on the neutrino flux from potential point sources. We compare these limits to ANITA's sensitivity in the same direction and show that an astrophysical explanation of these anomalous events under standard model assumptions is severely constrained regardless of source spectrum.
TL;DR: In this article, an extension of the measurement of the all-particle cosmic-ray spectrum with IceTop to lower energy was reported, which gave full coverage of the knee region of the spectrum and reduced the gap in energy between previous IceTop and direct measurements.
Abstract: We report here an extension of the measurement of the all-particle cosmic-ray
spectrum with IceTop to lower energy. The new measurement gives full coverage
of the knee region of the spectrum and reduces the gap in energy between
previous IceTop and direct measurements. With a new trigger that selects events
in closely spaced detectors in the center of the array, the IceTop energy
threshold is lowered by almost an order of magnitude below its previous
threshold of 2 PeV. In this paper, we explain how the new trigger is
implemented, and we describe the new machine-learning method developed to deal
with events with very few detectors hit. We compare the results with previous
measurements by IceTop and others that overlap at higher energy and with HAWC
and Tibet in the 100 TeV range.
TL;DR: In this article, a search for point-like and extended sources of cosmic neutrinos using data collected by the ANTARES and IceCube neutrino telescopes is presented.
Abstract: A search for point-like and extended sources of cosmic neutrinos using data collected by the ANTARES and IceCube neutrino telescopes is presented. The data set consists of all the track-like and shower-like events pointing in the direction of the Southern Sky included in the nine-year ANTARES point-source analysis, combined with the through-going track-like events used in the seven-year IceCube point-source search. The advantageous field of view of ANTARES and the large size of IceCube are exploited to improve the sensitivity in the Southern Sky by a factor $\sim$2 compared to both individual analyses. In this work, the Southern Sky is scanned for possible excesses of spatial clustering, and the positions of preselected candidate sources are investigated. In addition, special focus is given to the region around the Galactic Centre, whereby a dedicated search at the location of SgrA* is performed, and to the location of the supernova remnant RXJ 1713.7-3946. No significant evidence for cosmic neutrino sources is found and upper limits on the flux from the various searches are presented.
TL;DR: In this paper, the authors presented two searches for IceCube neutrino events coincident with 28 fast radio bursts (FRBs) and 1 repeating FRB and no significant correlation is found in either search; therefore, they set upper limits on the time-integrated neutrinos flux emitted by FRBs for a range of emission timescales less than one day.
Abstract: Author(s): Beatty, JJ; Aartsen, MG; Ackermann, M; Adams, J; Aguilar, JA; Ahlers, M; Ahrens, M; Alispach, C; Andeen, K; Anderson, T; Ansseau, I; Anton, G; Arguelles, C; Auffenberg, J; Axani, S; Backes, P; Bagherpour, H; Bai, X; V., AB; Barbano, A; Barwick, SW; Bastian, B; Baum, V; Baur, S; Bay, R; Beatty, JJ; Becker, KH; Becker Tjus, J; Benzvi, S; Berley, D; Bernardini, E; Besson, DZ; Binder, G; Bindig, D; Blaufuss, E; Blot, S; Bohm, C; Borner, M; Boser, S; Botner, O; Bottcher, J; Bourbeau, E; Bourbeau, J; Bradascio, F; Braun, J; Bron, S; Brostean-Kaiser, J; Burgman, A; Buscher, J; Busse, RS; Carver, T; Chen, C; Cheung, E; Chirkin, D; Choi, S; Clark, K; Classen, L; Coleman, A; Collin, GH; Conrad, JM; Coppin, P; Correa, P; Cowen, DF; Cross, R; Dave, P; Clercq, CD; Delaunay, JJ; Dembinski, H; Deoskar, K; Ridder, SD; Desiati, P; Vries, KDD; Wasseige, GD; With, MD; Deyoung, T; Diaz, A; Diaz-Velez, JC; Dujmovic, H; Dunkman, M; Dvorak, E; Eberhardt, B; Ehrhardt, T; Eller, P; Engel, R; Evenson, PA | Abstract: We present two searches for IceCube neutrino events coincident with 28 fast radio bursts (FRBs) and 1 repeating FRB. The first improves on a previous IceCube analysis - searching for spatial and temporal correlation of events with FRBs at energies greater than roughly 50 GeV - by increasing the effective area by an order of magnitude. The second is a search for temporal correlation of MeV neutrino events with FRBs. No significant correlation is found in either search; therefore, we set upper limits on the time-integrated neutrino flux emitted by FRBs for a range of emission timescales less than one day. These are the first limits on FRB neutrino emission at the MeV scale, and the limits set at higher energies are an order-of-magnitude improvement over those set by any neutrino telescope.
TL;DR: In this article, the authors used 9.5 years of all-sky IceCube data to search for neutrino emission from 35 PWNe that are high-energy gamma-ray emitters.
Abstract: Pulsar wind nebulae (PWNe) are the main gamma-ray emitters in the Galactic plane. They are diffuse nebulae that emit nonthermal radiation. Pulsar winds, relativistic magnetized outflows from the central star, shocked in the ambient medium produce a multiwavelength emission from the radio through gamma rays. Although the leptonic scenario is able to explain most PWNe emission, a hadronic contribution cannot be excluded. A possible hadronic contribution to the high-energy gamma-ray emission inevitably leads to the production of neutrinos. Using 9.5 yr of all-sky IceCube data, we report results from a stacking analysis to search for neutrino emission from 35 PWNe that are high-energy gamma-ray emitters. In the absence of any significant correlation, we set upper limits on the total neutrino emission from those PWNe and constraints on hadronic spectral components.
TL;DR: In this paper, an improved in-situ calibration of the single-photoelectron charge distributions for each of the in-ice Hamamatsu Photonics R7081-02[MOD] photomultiplier tubes in the IceCube Neutrino Observatory is described.
Abstract: We describe an improved in-situ calibration of the single-photoelectron charge distributions for each of the in-ice Hamamatsu Photonics R7081-02[MOD] photomultiplier tubes in the IceCube Neutrino Observatory. The characterization of the individual PMT charge distributions is important for PMT calibration, data and Monte Carlo simulation agreement, and understanding the effect of hardware differences within the detector. We discuss the single photoelectron identification procedure and how we extract the single-photoelectron charge distribution using a deconvolution of the multiple-photoelectron charge distribution.
TL;DR: In this article, the presence of a population of point sources in a data set modifies the underlying neutrino-count statistics from the Poisson distribution, and the deviation can be exactly quantified using the non-Poissonian template fitting technique, and in this work we present the first application of this approach to the IceCube high-energy neutrinos data set.
Abstract: The presence of a population of point sources in a data set modifies the underlying neutrino-count statistics from the Poisson distribution. This deviation can be exactly quantified using the non-Poissonian template fitting technique, and in this work we present the first application of this approach to the IceCube high-energy neutrino data set. Using this method, we search in 7 yr of IceCube data for point-source populations correlated with the disk of the Milky Way, the Fermi bubbles, the Schlegel, Finkbeiner, and Davis dust map, or with the isotropic extragalactic sky. No evidence for such a population is found in the data using this technique, and in the absence of a signal, we establish constraints on population models with source-count distribution functions that can be described by a power law with a single break. The derived limits can be interpreted in the context of many possible source classes. In order to enhance the flexibility of the results, we publish the full posterior from our analysis, which can be used to establish limits on specific population models that would contribute to the observed IceCube neutrino flux.
TL;DR: The AMON system is running continuously, receiving sub-threshold data (i.e., data that is not suited on its own to do astrophysical searches) from HAWC and IceCube, and combining them in real-time as discussed by the authors.
Abstract: The High Altitude Water Cherenkov (HAWC) and IceCube observatories, through the Astrophysical Multimessenger Observatory Network (AMON) framework, have developed a multimessenger joint search for extragalactic astrophysical sources. This analysis looks for sources that emit both cosmic neutrinos and gamma rays that are produced in photo-hadronic or hadronic interactions. The AMON system is running continuously, receiving sub-threshold data (i.e. data that is not suited on its own to do astrophysical searches) from HAWC and IceCube, and combining them in real-time. We present here the analysis algorithm, as well as results from archival data collected between June 2015 and August 2018, with a total live-time of 3.0 years. During this period we found two coincident events that have a false alarm rate (FAR) of $<1$ coincidence per year, consistent with the background expectations. The real-time implementation of the analysis in the AMON system began on November 20th, 2019, and issues alerts to the community through the Gamma-ray Coordinates Network with a FAR threshold of $<4$ coincidences per year.
TL;DR: The most stringent current constraints on their spin-dependent scattering cross-section with nucleons come from the IceCube neutrino observatory and the PICO-60 superheated bubble chamber experiments as discussed by the authors.
Abstract: Adopting the Standard Halo Model (SHM) of an isotropic Maxwellian velocity distribution for dark matter (DM) particles in the Galaxy, the most stringent current constraints on their spin-dependent scattering cross-section with nucleons come from the IceCube neutrino observatory and the PICO-60 $$\hbox {C}_3\hbox {F}_8$$
superheated bubble chamber experiments. The former is sensitive to high energy neutrinos from the self-annihilation of DM particles captured in the Sun, while the latter looks for nuclear recoil events from DM scattering off nucleons. Although slower DM particles are more likely to be captured by the Sun, the faster ones are more likely to be detected by PICO. Recent N-body simulations suggest significant deviations from the SHM for the smooth halo component of the DM, while observations hint at a dominant fraction of the local DM being in substructures. We use the method of Ferrer et al. (JCAP 1509: 052, 2015) to exploit the complementarity between the two approaches and derive conservative constraints on DM-nucleon scattering. Our results constrain $$\sigma _{\mathrm{SD}} \lesssim 3 \times 10^{-39} \mathrm {cm}^2$$
(
$$6 \times 10^{-38} \mathrm {cm}^2$$
) at $$\gtrsim 90\%$$
C.L. for a DM particle of mass 1 TeV annihilating into $$\tau ^+ \tau ^-$$
(
$$b\bar{b}$$
) with a local density of $$\rho _{\mathrm{DM}} = 0.3~\mathrm {GeV/cm}^3$$
. The constraints scale inversely with $$\rho _{\mathrm{DM}}$$
and are independent of the DM velocity distribution.
Journal Article•
TL;DR: In this article, the authors study the combined performance of the two future multi-purpose neutrino oscillation experiments JUNO and the IceCube Upgrade, which employ two distinct and complementary routes towards the neutrinos mass ordering.
Abstract: The ordering of the neutrino mass eigenstates is one of the fundamental open questions in neutrino physics. While current-generation neutrino oscillation experiments are able to produce moderate indications on this ordering, upcoming experiments of the next generation aim to provide conclusive evidence. In this paper we study the combined performance of the two future multi-purpose neutrino oscillation experiments JUNO and the IceCube Upgrade, which employ two very distinct and complementary routes towards the neutrino mass ordering. The approach pursued by the $20\\,\\mathrm{kt}$ medium-baseline reactor neutrino experiment JUNO consists of a careful investigation of the energy spectrum of oscillated $\\bar{\
u}_e$ produced by ten nuclear reactor cores. The IceCube Upgrade, on the other hand, which consists of seven additional densely instrumented strings deployed in the center of IceCube DeepCore, will observe large numbers of atmospheric neutrinos that have undergone oscillations affected by Earth matter. In a joint fit with both approaches, tension occurs between their preferred mass-squared differences $ \\Delta m_{31}^{2}=m_{3}^{2}-m_{1}^{2} $ within the wrong mass ordering. In the case of JUNO and the IceCube Upgrade, this allows to exclude the wrong ordering at $>5\\sigma$ on a timescale of 3--7 years --- even under circumstances that are unfavorable to the experiments' individual sensitivities. For PINGU, a 26-string detector array designed as a potential low-energy extension to IceCube, the inverted ordering could be excluded within 1.5 years (3 years for the normal ordering) in a joint analysis.
TL;DR: In this article, a scan of the whole sky, making no prior assumption about source candidates, is performed, looking for a space and time clustering of high-energy neutrinos in data collected by the IceCube Neutrino Observatory between 2012 and 2017.
Abstract: High-energy neutrinos are unique messengers of the high-energy universe, tracing the processes of cosmic-ray acceleration. This paper presents analyses focusing on time-dependent neutrino point-source searches. A scan of the whole sky, making no prior assumption about source candidates, is performed, looking for a space and time clustering of high-energy neutrinos in data collected by the IceCube Neutrino Observatory between 2012 and 2017. No statistically significant evidence for a time-dependent neutrino signal is found with this search during this period since all results are consistent with the background expectation. Within this study period, the blazar 3C 279, showed strong variability, inducing a very prominent gamma-ray flare observed in 2015 June. This event motivated a dedicated study of the blazar, which consists of searching for a time-dependent neutrino signal correlated with the gamma-ray emission. No evidence for a time-dependent signal is found. Hence, an upper limit on the neutrino fluence is derived, allowing us to constrain a hadronic emission model.
TL;DR: In this paper, the Neutrino Mass Ordering (NMO) remains one of the outstanding questions in the field of neutrino physics, and one strategy to measure the NMO is to observe matter effects in the oscillation pattern of the oscillations.
Abstract: The Neutrino Mass Ordering (NMO) remains one of the outstanding questions in the field of neutrino physics. One strategy to measure the NMO is to observe matter effects in the oscillation pattern o ...
TL;DR: In this article, the outer detector regions were used as veto and features of the signal pattern to reduce the background of atmospheric muons to a level which, for the first time, allowed IceCube searching for point-like sources of neutrinos in the southern sky at energies between 100GeV and several TeV in the muon neutrino charged current channel.
11 Oct 2020-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: A staged approach to the generation of binned event distributions is presented by combining multiple integration and smoothing techniques which address limited statistics from simulation and arrives at reliable analysis results using modest computational resources.
Abstract: The current and upcoming generation of Very Large Volume Neutrino Telescopes – collecting unprecedented quantities of neutrino events – can be used to explore subtle effects in oscillation physics, such as (but not restricted to) the neutrino mass ordering. The sensitivity of an experiment to these effects can be estimated from Monte Carlo simulations. With the high number of events that will be collected, there is a trade-off between the computational expense of running such simulations and the inherent statistical uncertainty in the determined values. In such a scenario, it becomes impractical to produce and use adequately-sized sets of simulated events with traditional methods, such as Monte Carlo weighting. In this work we present a staged approach to the generation of expected distributions of observables in order to overcome these challenges. By combining multiple integration and smoothing techniques which address limited statistics from simulation it arrives at reliable analysis results using modest computational resources.
TL;DR: The measurement of diffuse PeV gamma-ray emission from the Galactic plane would provide information about the energy spectrum and propagation of Galactic cosmic rays, and the detection of a point in the sky.
Abstract: The measurement of diffuse PeV gamma-ray emission from the Galactic plane would provide information about the energy spectrum and propagation of Galactic cosmic rays, and the detection of a pointli ...
Abstract: The distribution of galaxies within the local universe is characterized by anisotropic features. Observatories searching for the production sites of astrophysical neutrinos can take advantage of these features to establish directional correlations between a neutrino dataset and overdensities in the galaxy distribution in the sky. The results of two correlation searches between a seven-year time-integrated neutrino dataset from the IceCube Neutrino Observatory, and the 2MASS Redshift Survey (2MRS) catalog are presented here. The first analysis searches for neutrinos produced via interactions between diffuse intergalactic Ultra-High Energy Cosmic Rays (UHECRs) and the matter contained within galaxies. The second analysis searches for low-luminosity sources within the local universe, which would produce subthreshold multiplets in the IceCube dataset that directionally correlate with galaxy distribution. No significant correlations were observed in either analyses. Constraints are presented on the flux of neutrinos originating within the local universe through diffuse intergalactic UHECR interactions, as well as on the density of standard candle sources of neutrinos at low luminosities.
Posted Content•
TL;DR: In this paper, the authors presented the first all-flavor search from IceCube for transient emission of low-energy neutrinos, between 1-100 GeV using three years of data obtained with the IceCube-DeepCore detector.
Abstract: 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, between 1-100 GeV using three years of data obtained with the IceCube-DeepCore detector. We find no evidence of transient neutrino emission in the data, thus leading to a constraint on the volumetric rate of astrophysical transient sources in the range of $\sim 705-2301\, \text{Gpc}^{-3}\, \text{yr}^{-1}$ for sources following a subphotospheric energy spectrum with a mean energy of 100 GeV and a bolometric energy of $10^{52}$ erg.
TL;DR: In this paper, the first results of a 7-pixel imaging air Cherenkov telescope demonstrator are presented, proving the capability of this technology to measure air showers at the South Pole in coincidence with IceTop and the deep IceCube detector.
Abstract: In this paper we describe the first results of IceAct, a compact imaging air-Cherenkov telescope operating in coincidence with the IceCube Neutrino Observatory (IceCube) at the geographic South Pole. An array of IceAct telescopes (referred to as the IceAct project) is under consideration as part of the IceCube-Gen2 extension to IceCube. Surface detectors in general will be a powerful tool in IceCube-Gen2 for distinguishing astrophysical neutrinos from the dominant backgrounds of cosmic-ray induced atmospheric muons and neutrinos: the IceTop array is already in place as part of IceCube, but has a high energy threshold. Although the duty cycle will be lower for the IceAct telescopes than the present IceTop tanks, the IceAct telescopes may prove to be more effective at lowering the detection threshold for air showers. Additionally, small imaging air-Cherenkov telescopes in combination with IceTop, the deep IceCube detector or other future detector systems might improve measurements of the composition of the cosmic ray energy spectrum. In this paper we present measurements of a first 7-pixel imaging air Cherenkov telescope demonstrator, proving the capability of this technology to measure air showers at the South Pole in coincidence with IceTop and the deep IceCube detector.
01 Jan 2020
TL;DR: In this article, the authors describe the fundamentals of particle detectors in their different forms as well as their applications, presenting the abundant material as clearly as possible and as deeply as needed for a thorough understanding.
Abstract: The book describes the fundamentals of particle detectors in their different forms as well as their applications, presenting the abundant material as clearly as possible and as deeply as needed for a thorough understanding. The target group for the book are both, students who want to get an introduction or wish to deepen their knowledge on the subject as well as lecturers and researchers who intend to extent their expertise. The book is also suited as a preparation for instrumental work in nuclear, particle and astroparticle physics and in many other fields (addressed in chapter 2). The detection of elementary particles, nuclei and high-energetic electromagnetic radiation, in this book commonly designated as ‘particles’, proceeds through interactions of the particles with matter. A detector records signals originating from the interactions occurring in or near the detector and (in general) feeds them into an electronic data acquisition system. The book describes the various steps in this process, beginning with the relevant interactions with matter, then proceeding to their exploitation for different detector types like tracking detectors, detectors for particle identification, detectors for energy measurements, detectors in astroparticle experiments, and ending with a discussion of signal processing and data acquisition. Besides the introductory and overview chapters (chapters 1 and 2), the book is divided into five subject areas: – fundamentals (chapters 3 to 5), – detection of tracks of charged particles (chapters 6 to 9), – phenomena and methods mainly applied for particle identification (chapters 10 to 14), – energy measurement (accelerator and non-accelerator experiments) (chapters 15, 16), – electronics and data acquisition (chapters 17 and 18). Comprehensive lists of literature, keywords and abbreviations can be found at the end of the book.