arXiv subjects

D. Guderian

Publications and source records attributed to D. Guderian.

9 recordsLinked to original sources

arXiv2021

Implementation and first results of the KM3NeT real-time core-collapse supernova neutrino search

The KM3NeT research infrastructure is under construction in the Mediterranean Sea. KM3NeT will study atmospheric and astrophysical neutrinos with two multi-purpose neutrino detectors, ARCA and ORCA, primarily aimed at GeV-PeV neutrinos. Thanks to the multi-photomultiplier tube design of the digital optical modules, KM3NeT is capable of detecting the neutrino burst from a Galactic or near-Galactic core-collapse supernova. This potential is already exploitable with the first detection units deployed in the sea. This paper describes the real-time implementation of the supernova neutrino search, operating on the two KM3NeT detectors since the first months of 2019. A quasi-online astronomy analysis is introduced to study the time profile of the detected neutrinos for especially significant events. The mechanism of generation and distribution of alerts, as well as the integration into the SNEWS and SNEWS 2.0 global alert systems are described. The approach for the follow-up of external alerts with a search for a neutrino excess in the archival data is defined. Finally, an overview of the current detector capabilities and a report after the first two years of operation are given.

astro-ph.HE↗

arXiv2021

Determining the Neutrino Mass Ordering and Oscillation Parameters with KM3NeT/ORCA

The next generation of water Cherenkov neutrino telescopes in the Mediterranean Sea are under construction offshore France (KM3NeT/ORCA) and Sicily (KM3NeT/ARCA). The KM3NeT/ORCA detector features an energy detection threshold which allows to collect atmospheric neutrinos to study flavour oscillation. This paper reports the KM3NeT/ORCA sensitivity to this phenomenon. The event reconstruction, selection and classification are described. The sensitivity to determine the neutrino mass ordering was evaluated and found to be 4.4 $σ$ if the true ordering is normal and 2.3 $σ$ if inverted, after three years of data taking. The precision to measure $Δm^2_{32}$ and $θ_{23}$ were also estimated and found to be $85\cdot10^{-6}$ eV$^2$ and $(^{+1.9}_{-3.1})^{\circ}$ for normal neutrino mass ordering and, $75\cdot10^{-6}$ eV$^2$ and $(^{+2.0}_{-7.0})^{\circ}$ for inverted ordering. Finally, a unitarity test of the leptonic mixing matrix by measuring the rate of tau neutrinos is described. Three years of data taking were found to be sufficient to exclude $ν_τ$ and $\barν_τ$ event rate variations larger than 20% at $3σ$ level.

hep-ex↗

arXiv2021

Sensitivity to light sterile neutrino mixing parameters with KM3NeT/ORCA

KM3NeT/ORCA is a next-generation neutrino telescope optimised for atmospheric neutrino oscillations studies. In this paper, the sensitivity of ORCA to the presence of a light sterile neutrino in a 3+1 model is presented. After three years of data taking, ORCA will be able to probe the active-sterile mixing angles $θ_{14}$, $θ_{24}$, $θ_{34}$ and the effective angle $θ_{μe}$, over a broad range of mass squared difference $Δm^2_{41} \sim [10^{-5}, 10]$ $\rm{eV}^2$, allowing to test the eV-mass sterile neutrino hypothesis as the origin of short baseline anomalies, as well as probing the hypothesis of a very light sterile neutrino, not yet constrained by cosmology. ORCA will be able to explore a relevant fraction of the parameter space not yet reached by present measurements.

hep-ex↗

arXiv2021

Nanobeacon: A time calibration device for the KM3NeT neutrino telescope

The KM3NeT Collaboration is currently constructing a multi-site high-energy neutrino telescope in the Mediterranean Sea consisting of matrices of pressure-resistant glass spheres, each holding a set of 31 small-area photomultipliers. The main goals of the telescope are the observation of neutrino sources in the Universe and the measurement of the neutrino oscillation parameters with atmospheric neutrinos. Both extraterrestrial and atmospheric neutrinos are detected through the Cherenkov light induced in seawater by charged particles produced in neutrino interactions in the surrounding medium. A relative time synchronization between photomultipliers of the order of 1 ns is needed to guarantee the required angular resolution of the detector. Due to the large detector volumes to be instrumented by KM3NeT, a cost reduction of the different systems is a priority. To this end, the inexpensive Nanobeacon has been designed and developed by the KM3NeT Collaboration to be used for detector time-calibration studies. At present, more than 600 Nanobeacons have been already produced. The characterization of the optical pulse and the wavelength emission profile of the devices are critical for the time calibration. In this paper, the main features of the Nanobeacon design, production and operation, together with the main properties of the light pulse generated are described.

astro-ph.IM↗

arXiv2021

Graph Neural Networks for reconstruction and classification in KM3NeT

KM3NeT, a neutrino telescope currently under construction in the Mediterranean Sea, consists of a network of large-volume Cherenkov detectors. Its two different sites, ORCA and ARCA, are optimised for few GeV and TeV-PeV neutrino energies, respectively. This allows for studying a wide range of physics topics spanning from the determination of the neutrino mass hierarchy to the detection of neutrinos from astrophysical sources. Deep Learning techniques provide promising methods to analyse the signatures induced by charged particles traversing the detector. This document will cover a Deep Learning based approach using Graph Convolutional Networks to classify and reconstruct events in both the ORCA and ARCA detector. Performance studies on simulations as well as applications to real data will be presented, together with comparisons to classical approaches.

astro-ph.IM↗

arXiv2021

Combined sensitivity of JUNO and KM3NeT/ORCA to the neutrino mass ordering

This article presents the potential of a combined analysis of the JUNO and KM3NeT/ORCA experiments to determine the neutrino mass ordering. This combination is particularly interesting as it significantly boosts the potential of either detector, beyond simply adding their neutrino mass ordering sensitivities, by removing a degeneracy in the determination of $Δm_{31}^2$ between the two experiments when assuming the wrong ordering. The study is based on the latest projected performances for JUNO, and on simulation tools using a full Monte Carlo approach to the KM3NeT/ORCA response with a careful assessment of its energy systematics. From this analysis, a $5σ$ determination of the neutrino mass ordering is expected after 6 years of joint data taking for any value of the oscillation parameters. This sensitivity would be achieved after only 2 years of joint data taking assuming the current global best-fit values for those parameters for normal ordering.

hep-ex↗

arXiv2021

The KM3NeT potential for the next core-collapse supernova observation with neutrinos

The KM3NeT research infrastructure is under construction in the Mediterranean Sea. It consists of two water Cherenkov neutrino detectors, ARCA and ORCA, aimed at neutrino astrophysics and oscillation research, respectively. Instrumenting a large volume of sea water with $\sim$ 6,200 optical modules comprising a total of $\sim$ 200,000 photomultiplier tubes, KM3NeT will achieve sensitivity to $\sim$ 10 MeV neutrinos from Galactic and near-Galactic core-collapse supernovae through the observation of coincident hits in photomultipliers above the background. In this paper, the sensitivity of KM3NeT to a supernova explosion is estimated from detailed analyses of background data from the first KM3NeT detection units and simulations of the neutrino signal. The KM3NeT observational horizon (for a $5\,σ$ discovery) covers essentially the Milky-Way and for the most optimistic model, extends to the Small Magellanic Cloud ($\sim$ 60 kpc). Detailed studies of the time profile of the neutrino signal allow assessment of the KM3NeT capability to determine the arrival time of the neutrino burst with a few milliseconds precision for sources up to 5$-$8 kpc away, and detecting the peculiar signature of the standing accretion shock instability if the core-collapse supernova explosion happens closer than 3$-$5 kpc, depending on the progenitor mass. KM3NeT's capability to measure the neutrino flux spectral parameters is also presented.

astro-ph.HE↗

arXiv2019

The Control Unit of the KM3NeT Data Acquisition System

The KM3NeT Collaboration runs a multi-site neutrino observatory in the Mediterranean Sea. Water Cherenkov particle detectors, deep in the sea and far off the coasts of France and Italy, are already taking data while incremental construction progresses. Data Acquisition Control software is operating off-shore detectors as well as testing and qualification stations for their components. The software, named Control Unit, is highly modular. It can undergo upgrades and reconfiguration with the acquisition running. Interplay with the central database of the Collaboration is obtained in a way that allows for data taking even if Internet links fail. In order to simplify the management of computing resources in the long term, and to cope with possible hardware failures of one or more computers, the KM3NeT Control Unit software features a custom dynamic resource provisioning and failover technology, which is especially important for ensuring continuity in case of rare transient events in multi-messenger astronomy. The software architecture relies on ubiquitous tools and broadly adopted technologies and has been successfully tested on several operating systems.

astro-ph.IM↗

arXiv2019

KM3NeT front-end and readout electronics system: hardware, firmware and software

The KM3NeT research infrastructure being built at the bottom of the Mediterranean Sea will host water-Cherenkov telescopes for the detection of cosmic neutrinos. The neutrino telescopes will consist of large volume three-dimensional grids of optical modules to detect the Cherenkov light from charged particles produced by neutrino-induced interactions. Each optical module houses 31 3-inch photomultiplier tubes, instrumentation for calibration of the photomultiplier signal and positioning of the optical module and all associated electronics boards. By design, the total electrical power consumption of an optical module has been capped at seven watts. This paper presents an overview of the front-end and readout electronics system inside the optical module, which has been designed for a 1~ns synchronization between the clocks of all optical modules in the grid during a life time of at least 20 years.

astro-ph.IM↗