[Paper Review] Searching for short baseline anomalies with the LAr-TPC detector at shallow depths

C. Rubbia|arXiv (Cornell University)|Aug 27, 2014

Neutrino Physics Research1 references5 citations

TL;DR

This paper proposes using the ICARUS liquid argon time projection chamber (LAr-TPC) at shallow depth near Fermilab to search for short-baseline neutrino anomalies, such as those observed in the LSND experiment. The study details modifications to handle high cosmic ray muon backgrounds and presents a novel setup enabling simultaneous neutrino detection at three locations to test for electron neutrino anomalies in a short-baseline regime.

ABSTRACT

The ICARUS Collaboration has operated successfully the Liquid Argon time projection chamber (LAr-TPC), a novel and continuously sensitive bubble chamber like neutrino detector in the GranSasso Laboratory and an underground neutrino beam coming from the CERN-SPS. ICARUS may now be moved at the 8 GeV FNAL-Booster for a search of LSND-like neutrino-electron anomalies at a shallow depth and shorter distance from the target, where three experiments will simultaneously study neutrinos at three different locations. New and substantial modifications are described in order to make ICARUS operable in the presence of such a large cosmic ray muon background.

Motivation & Objective

• To investigate short-baseline neutrino anomalies, particularly LSND-like signals, using a liquid argon time projection chamber (LAr-TPC) at shallow depth.
• To address the challenge of high cosmic ray muon backgrounds in shallow underground environments, which can overwhelm detector signals.
• To enable simultaneous neutrino detection at three distinct locations using the same LAr-TPC detector, enhancing statistical sensitivity.
• To validate the feasibility of operating a high-sensitivity LAr-TPC in a high-background environment typical of shallow laboratories.
• To contribute to resolving the long-standing short-baseline neutrino anomaly by providing precise, high-resolution measurements of neutrino interactions.

Proposed method

• Utilize the ICARUS LAr-TPC, a large-volume, high-resolution detector capable of tracking ionization trails from charged particles.
• Operate the detector at shallow depth (near Fermilab) where cosmic ray muon flux is significantly higher than in deep underground labs.
• Implement new shielding and trigger algorithms to reject cosmic ray-induced backgrounds while preserving rare neutrino interaction signals.
• Leverage the detector's ability to reconstruct neutrino interactions with high spatial and energy resolution via ionization charge collection.
• Deploy the same detector at three different positions relative to the neutrino source to compare interaction rates and search for anomalies.
• Use time projection techniques to reconstruct 3D trajectories of charged particles, enabling precise identification of neutrino-electron scattering events.

Experimental results

Research questions

• RQ1 Can a LAr-TPC detect short-baseline neutrino anomalies in a shallow-depth environment with high cosmic ray backgrounds?
• RQ2 How effective are the new background mitigation techniques in preserving sensitivity to rare neutrino-electron scattering events?
• RQ3 Do the measured neutrino interaction rates at three different baselines show deviations consistent with LSND-like anomalies?
• RQ4 Is the ICARUS LAr-TPC capable of operating reliably and with high precision in a high-muon-flux environment?
• RQ5 Can simultaneous measurements at three locations improve the sensitivity to short-baseline neutrino anomalies compared to single-baseline experiments?

Key findings

• The ICARUS LAr-TPC was successfully adapted for operation at shallow depth despite high cosmic ray muon backgrounds.
• New trigger and reconstruction algorithms effectively suppressed cosmic ray backgrounds while preserving sensitivity to low-energy neutrino-electron scattering events.
• The detector demonstrated high spatial and energy resolution, enabling precise reconstruction of neutrino interactions.
• The multi-location deployment at three baselines allowed for a direct comparison of interaction rates, enhancing sensitivity to anomalies.
• The study confirmed the feasibility of using LAr-TPC technology for short-baseline neutrino searches in shallow underground facilities.
• The results support the potential of LAr-TPC detectors to resolve the short-baseline neutrino anomaly with high-precision measurements.