Atmospheric neutrino studies at ESSnuSB far detector

NAISS 2023/22-934


NAISS Small Compute

Principal Investigator:

Sampsa Vihonen


Kungliga Tekniska högskolan

Start Date:


End Date:


Primary Classification:

10301: Subatomic Physics



The European Spallation Source neutrino Super Beam (ESSnuSB) is a future neutrino oscillation experiment that has been proposed to study neutrino oscillations in Sweden. The primary goal of the experiment is to search for leptonic CP violation and measure its size by using the accelerator facilities at the European Spallation Source (ESS) in Lund. The experiment setup consists of the neutrino source and several neutrino detector facilities, the largest of which proposed to be located at the Zinkruvan mine about 360 km from Lund. We request computing resources to investigate non-beam physics program at the far detector facility of the ESSnuSB. The far detector is planned to be a megaton-scale Water Cherenkov detector where large volumes of ultrapure water will be used as target for the beam neutrinos. The detector design does not only have very good capabilities to detect accelerator neutrinos from the ESS facility, but it is also capable of probing neutrinos of astrophysical origin including cosmic rays, supernovae and other natural sources. In this project, we investigate the detector's prospects to detect atmospheric neutrinos, which are neutrinos that are born in the atmosphere due to interactions with cosmic rays. Atmospheric neutrinos are born all around the atmosphere and they often traverse very long distances inside the Earth before reaching neutrino detector. Owing to the relatively strong exposure to matter effects, atmospheric neutrinos have good prospects at shedding light on the question of neutrino mass ordering and improving constraints on the standard neutrino oscillation parameters. Atmospheric neutrinos can furthermore be used to seek hints of non-standard interactions, which also benefit from strong matter effects. In this work, we will use the Monte Carlo event generator GENIE to simulate the atmospheric neutrino interactions inside the ESSnuSB far detector. GENIE is a universal neutrino event generator that is widely used to simulate neutrino interactions in next-generation neutrino experiments. Using our own analysis software, we will analyze the neutrino event data generated by GENIE and estimate the sensitivities to relevant physics questions at the ESSnuSB far detector facility. The initial goal of our work is to study the detector's prospects in the determination of the neutrino mass hierarchy, which is strongly dependent on neutrinos' exposure to matter effects. We will also calculate the impact of the atmospheric neutrino data on the precision of the standard neutrino oscillation parameters and evaluate its prospects to search non-standard neutrino interactions. This work is carried out as part of the ESSnuSB+ project, which is co-funded by the European Union and involves researchers from 20 institutions from 11 countries. We request access for a total of 12 months.