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The Columbia neutrino group at Nevis Labs is involved in a number of accelerator-based neutrino experiments, all of which involve the same detection technology, that of a liquid argon time projection chamber (LArTPC).

MicroBooNE is a neutrino experiment at Fermilab that is investigating neutrino properties and interactions using the Fermilab booster neutrino beam. It is a follow-up experiment to the MiniBooNE experiment, which also ran in the Fermilab booster neutrino beam. MiniBooNE observed an enhanced number of low energy events over expectation with characteristics that imply the events have outgoing electrons or photons. Since electron neutrinos produce electrons in their charged current interactions, one interpretation is that these extra events are due to more electron neutrino interactions than expectation. An alternative explanation is that they are due to an unexpected number of neutrino events producing photons in the final state. In either case, the anomalous MiniBooNE signal may be from some type of new physics either within or beyond the current particle physics model.

MicroBooNE will have the capability to distinguish between electrons and photons by using a time projection chamber (TPC) filled with 175 tons of liquid argon. This detector will have excellent spatial and energy resolution and will be able to differentiate between an electron from an electron neutrino interaction and a photon; an electron will produce a track originating at the main interaction vertex, while a photon will travel some distance from the vertex before converting and producing a track. MicroBooNE’s superb pattern recognition capabilities will also allow improved measurements of several neutrino cross sections. MicroBooNE will also be a test setup for future very large (~10-100 kton) liquid argon detectors, such as DUNE, planned for studies of CP violation in neutrino interactions, proton decay and Super Novae detection. It will allow R&D on liquid argon purity, mechanical configurations and electronic readout designs.

The Columbia neutrino group at Nevis Labs were prime members involved in the design and construction of the readout electronics for the MicroBooNE detector. Presently, the group is involved in developing pattern recognition analysis procedures to distinguish between neutrino interactions and background events and between electrons and photons. Part of this involves applying “deep learning” convolutional neural net techniques that use machine learning to train computers to recognize and isolate features in images such as those from the MicroBooNE liquid argon TPC. The group’s prime physics topic is investigating the MiniBooNE low energy excess and neutrino oscillation to sterile neutrinos using MicroBooNE in combination with the other detectors at Fermilab.

MicroBooNE is presently in full data taking mode and has collected almost the full data set needed for its physics goals. This summer will be an intense time for looking at the data, developing neutrino event reconstruction and selection software, and updating the oscillation physics simulations and sensitivity studies, leading to the first ever MicroBooNE physics results. We plan for several REU students to be based at Nevis Labs and be involved in all of these efforts, along with possibly helping with electronics testing for the upcoming SBND experiment, the near detector for the Short-Baseline Neutrino (SBN) program, or simulation studies for the future DUNE experiment.

Contact persons: Georgia Karagiorgi and Mike Shaevitz