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Update of gSeaGen simulation software

23 November 2024 – In a new paper with the title ‘gSeaGen code by KM3NeT: an efficient tool to propagate muons simulated with CORSIKA’ we describe an open source solution for efficient simulation of cosmic-ray induced muons in neutrino telescopes.

For this, we adapted the gSeaGen code, which generates high statistic samples of simulated neutrino-induced events, detectable by neutrino telescopes.

Updated gSeaGen can now also process muons from cosmic-ray induced particle showers in the atmosphere, which are generated by the Monte Carlo simulation code CORSIKA.

The tracking of muons towards the simulated detector offers efficient re-use of the particle shower when a muon misses the detector. We added several other new functionalities for computational efficiency and user control.

We updated gSeaGen with KM3NeT in mind, but other under-ground, under-water, or under-ice experiments may profit from it as well.

The paper is submitted to Computer Physics Communications
A preprint is available at: https://arxiv.org/abs/2410.24115

In the image:
Sketch of the projection of the side area of the detector (the ‘can’) onto the sea surface.

KM3NeT gathered online for its fall collaboration meeting

13 November 2024 – Last week , the KM3NeT Collaboration has met online for its fall meeting.

During the meeting, we reviewed the current status of data taking for both ARCA and ORCA detectors, discussed the advancements in their construction, the progresses in MC simulation and detector calibration, and outlined the plans for the ongoing data analyses.

It was also the occasion to celebrate our two last sea campaigns and thus the expanded configurations of the detectors, ARCA 33 and ORCA24. The deployment of new instrumentation on the ORCA site will allow for a precise monitoring of the detector position and water properties.

During the meeting Antoine Kouchner started his mandate as chairperson of the Institute Board, taking over from Uli Katz: with many thanks to Uli for all the work done in the past years, and good luck to Antoine for his new duty.

Also during the meeting, the process to elect the new Management Team of the Collaboration was started.

Finally, KM3NeT gave a heartfelt greeting to its new members. Juan Antonio Aguilar Sánchez of the Université Libre de Bruxelles, Belgium, and Elisa Bernardini of Padova University, Italy, joined as Observers, while the team led by Arthur Ukleja from the University of Krakow, Poland, was endorsed as Full Member.

A warm welcome to everyone!

It was great to see the advancements in the physics analyses as well as the simulation and calibration works, to discuss recent scientific advancements and to see the Collaboration continue to grow.

The next Collaboration Meeting is scheduled for January, in Belgium, at Louvain-la-Neuve.

Quantum decoherence with ORCA6

30 October 2024 – Search for quantum decoherence in neutrino oscillations with six detection units of KM3NeT/ORCA

(KM3NeT paper, submitted to JCAP, arXiv: 2410.01388)

In a new paper we search for quantum decoherence in neutrino oscillations by looking for deviations of the standard neutrino oscillation pattern. We report upper limits on the decoherence parameters using data from ORCA6.

Usually, neutrino oscillations are studied in the framework of quantum mechanics assuming that the neutrino system is isolated. In this paper we study neutrino oscillations in the framework of open quantum systems, where the neutrino is coupled to a larger environment.

Several theories of quantum gravity postulate fluctuations in spacetime as a stochastic environment. A neutrino that propagates in such an environment will experience changes to its quantum phase. This will lead to a loss of coherence of the neutrino mass eigenstates during propagation. The phenomenon is referred to as decoherence in neutrino oscillations.

The search for decoherence in neutrino oscillations provides a rare opportunity to investigate quantum gravitational effects which are usually beyond the reach of current experiments.

The ORCA detector of KM3NeT is particularly designed to detect neutrinos generated in collision of cosmic ray particles with the Earth’s atmosphere. The atmospheric neutrinos are good probes to study oscillations and hence to search for quantum decoherence effects.

We used the neutrino data collected by the ORCA6 detector – an early detector configuration with six detection units – in the period January 2020 to November 2021. In the analysis we focused on atmospheric neutrinos with energies of a few GeV to 100 GeV. We measured the parameters Γ₂₁and Γ₃₁, that describe decoherence, assuming a power-law dependency on the neutrino energy Γ_ij ∝ (E/E₀)ⁿand explored two cases: with n = -2 and with n = -1.

Results

No significant deviation with respect to the standard oscillation hypothesis is observed. Therefore, 90% CL upper limits for the two cases are estimated as

The decoherence sensitivity of ORCA depends on the neutrino mass ordering. Therefore, we report upper limits for both normal and inverted ordering.

The results are comparable to bounds reported for IceCube/DeepCore and display the same dependency on the mass ordering.

In the figure below the 90% confidence level contours for Γ₂₁ and Γ₃₁ are shown for a decoherence model fitting both normal (NO) and inverted (IO) neutrino mass orderings.

KM3NeT on display at the “Des abysses au cosmos” exhibition

From the 15th of September to the 8th of October, KM3NeT is represented at the exhibition “Des abysses au cosmos” (From the abyss to the cosmos), at the Fort Napoléon cultural centre in La Seyne-sur-Mer, France, operating quarters of the ANTARES and KM3NeT experiments.

The exhibition presents 20 years of underwater exploration of the cosmos, as well as the scientific and technological challenges and innovations involved in studying neutrinos and the deep marine environment. Organised by the CPPM and the City Hall of la Seyne-sur-Mer, this exhibition is aimed at the general public as well as primary and secondary school students.

Posters, photos, miniatures, objects and mini-interviews about KM3NeT are displayed, showing the scientific and technological efforts done by the Collaboration since the beginnings of the experiment to the present day. The KM3NeT-INFRADEV2 project is also represented to highlight the Collaboration’s commitment towards the full implementation of a reliable and sustainable KM3NeT international Research Infrastructure. A section is also dedicated to women in science, presenting the involvement of women scientists, engineers and technicians in KM3NeT.

An exhibition that will take its visitors to a depth of more than 2400 metres and behind the scenes of international research!

Some of the objects presented at the exhibit (by Chiara Lastoria)

Some pictures of the exhibition opening, on the 14^th of September (by Victoria Ciarlet)

More information on the exhibition: https://cppm.in2p3.fr/abysses-cosmos

KM3NeT presented at conferences worldwide

15 September 2023 – This summer, KM3NeT members participated in conferences all over the world to present the latest results and developments of our Collaboration.

Besides TAUP in Vienna, EPS-HEP in Hamburg, and TeVPA in Naples, KM3NeT-ers have massively attended the 38th International Cosmic Ray Conference (ICRC), in Nagoya, Japan. Since the ICRC is among the largest conferences in the field of astroparticle physics, it was an ideal opportunity for reporting the progress of the collaboration in neutrino astronomy, neutrino physics, multi-messenger astronomy, cosmic rays, and dark matter searches.

In total, KM3NeT presented 10 talks and 28 posters at the ICRC, in addition to a plenary talk given by prof. Antoine Kouchner, the spokesperson of the ANTARES Collaboration, on catching neutrinos in the Mediterranean Sea.

Interested?

The full proceedings of ICRC2023 can be found here. For your convenience, the contributions of KM3NeT to the proceedings are available here and are also on arXiv: https://arxiv.org/abs/2309.05016.

Antoine Kouchner, spokesperson of the ANTARES Collaboration, presenting at the ICRC2023 an overview of recent work achieved by ANTARES and KM3NeT.

Some of the talks given by KM3NeT members at the ICRC2023.

Some of the posters presented by KM3NeT members at the ICRC2023.

Three more detection units for KM3NeT/ORCA

1 May 2023 – During a two days sea operation, 27-28 April 2023, three detection units were successfully connected to the ORCA detector of KM3NeT in a record time of just over 24 hours. In addition, an acoustic beacon was recovered for battery replacement. The total number of deployed ORCA units is now 18, as visible in the sonar scan above.

As usual, the operation was performed with two ships: the Castor of Foselev, for deployment of the detection units, and the Janus II of SAAS (formerly Comex), equipped with a deep-sea remotely operated vehicle, for submarine operations.

Many thanks to the crews offshore as well as to the team who performed the functional tests of the new detection units from the shore station!

The KM3NeT-INFRADEV2 project is launched

27 March 2023 – The kick-off Meeting of the KM3NeT-INFRADEV2 project, funded by the European Union, marked the official start of a new step toward the full implementation of the KM3NeT Research Infrastructure.

Involving institutes, laboratories and universities from France, Italy, Germany, Greece, The Netherlands, and Spain, this three-year European project aims to support the creation of a KM3NeT legal entity, accelerates the implementation of the detectors, develops the data management and open science practices of the collaboration as well as ensures a sustainable future for the infrastructure.

During the online meeting, each work package was presented to all partners involved and to Ioannis Andredakis, the Project Officer for the INFRADEV2 project from the European Research Executive Agency.

The leaders of the working groups and their team members also had the opportunity to further discuss their work together, giving a very positive start to the project.

For the next three years and thanks to the European funding, the consortium will continue firmly with the development and successful operation of the KM3NeT neutrino observatory.

Major upgrade of ARCA’s seafloor network

22 November 2022 – After 4 years of activities carried out by the Italian funding agency INFN and Alcatel Submarine Networks, part of Nokia, the new subsea network for KM3NeT ARCA, funded under the Idmar regional project in Italy, is now complete.

The new system comprises a 100 km long electro-optical cable, equipped with 48 optical fibres for detector control and data communication and two electrical conductors for power distribution, connected to the shore station control and power feeding equipment, that can deliver up to 80 kW offshore. The cable is bifurcated in order to serve the two building blocks foreseen in ARCA.

During a 10 days long sea operation, which ended on November 17^th, a cable termination frame (CTF) was installed on the northern branch of the cable. To this purpose the end of the cable, which was deployed already in 2020, was recovered from the sea floor and connected to the CTF onboard the deployment ship – the Ile d’Ouessant of Alcatel Submarine Networks. Then the CTF was carefully deployed to the target position on the sea floor. Extensive tests were done before and after the deployment to ensure its nominal behaviour.

The CTF is a large-size, 12-ton component which is equipped with four medium voltage converters and a total of 16 electrical and optical subsea connectors for connecting a set of submarine junction boxes to which the detection units will be in turn connected.

With this installation the connectivity and power transmission capabilities of the network have been increased by a factor four compared to the first part of the network, used to run the set of junction boxes and the first 30 detection units of ARCA Phase 1. This will allow for the completion of the construction of the first building block of ARCA and prepares the field for the installation of a second CTF on the other branch of the cable for the second building block.

Sea campaign for ARCA concluded: welcome, KM3NeT/ARCA19!

14 June 2022 – The sea campaign for enlarging the KM3NeT/ARCA submarine telescope has been completed with full success!

During the last few days, all detection units loaded on Handin Tide for the second phase of the operation were carefully installed on the sea bottom. This was achieved at a record-breaking speed, with 7 detection units installed, connected and unfurled in less than 48 hours!

As a result of the campaign, the size of ARCA has more than doubled. It now comprises 19 detection units in operation, equipped with more than 10,000 photomultipliers,

We thank the teams which worked tirelessly offshore and onshore to reach this remarkable success. And we can’t forget that this was made possible by the hard work ongoing in the almost 30 integration sites of the Collaboration.

The activities at sea went around the clock during the campaign.

The shore station during the campaign – more than 30 people were involved in the onshore team for this campaign.

Welcome KM3NeT/ARCA19

14 June 2022 – The sea campaign for enlarging the KM3NeT/ARCA submarine telescope which was started on June 2, has been completed today with a full success. As a result, data taking with ARCA has been resumed with 19 detection units in operation!

This represents a major step forward for the collaboration, as this was the first time that a 2-weeks campaign was performed. The scope of the operation in fact was twofold: to upgrade the submarine network, by installing 2 new junction boxes in replacement of the junction box that we had been operating so far, and to install 11 new detection units (DUs). The operation therefore took place in two steps: after the first round of activities for installation of the junction boxes and the first 4 DUs, the ship went back to shore to pick up the remaining set of 7 DUs.

The campaign was performed with Handin Tide, of the FUGRO company, which had already performed the previous sea campaign for KM3NeT/ARCA last year, sailing off from Malta.

All planned activities were performed with full success, including ancillary operations such as the replacement of one autonomous acoustic beacon on the sea floor. A speed record was also established, with 7 detection units installed, connected and unfurled in less than 48 hours!

As a result of the campaign, the size of ARCA has more than doubled: It now comprises 19 detection units in operation, equipped with more than 10,000 photomultipliers,

The KM3NeT collaboration wishes to thank the Handin Tide crew for their top-level performance, the KM3NeT teams which worked tirelessly offshore and onshore to reach this remarkable success, as well as all teams which work so hard at the almost 30 integration sites of the collaboration to produce the DUs for building the apparatus.

Below is a gallery of pictures from the campaign. A log of the activities while the operation was ongoing is available on our blog.

Detection units in the port of Malta awaiting deployment.

Loading of a detection unit onto Handin Tide.

Handin Tide leaving Malta for the first phase of the campaign.

Deployment of one of the junction boxes installed in the campaign.