Search for an anomalous excess of charged-current $ν_e$ interactions without pions in the final state with the MicroBooNE experiment

Abstract

This article presents a measurement of νe interactions without pions in the final state using the MicroBooNE experiment and an investigation into the excess of low-energy electromagnetic events observed by the MiniBooNE collaboration. The measurement is performed in exclusive channels with (1eNp0π) and without (1e0p0π) visible final-state protons using 6.86×10 20 protons on target of data collected from the Booster Neutrino Beam at Fermilab. Events are reconstructed with the Pandora pattern recognition toolkit and selected using additional topological information from the MicroBooNE liquid argon time projection chamber. Using a goodness-of-fit test the data are found to be consistent with the predicted number of events with nominal flux and interaction models with a p-value of 0.098 in the two channels combined. A model based on the low-energy excess observed in MiniBooNE is introduced to quantify the strength of a possible νe excess. The analysis suggests that if an excess is present, it is not consistent with a simple scaling of the νe contribution to the flux. Combined, the 1eNp0π and 1e0p0π channels do not give a conclusive indication about the tested model, but separately they both disfavor the low-energy excess model at >90% CL. The observation in the most sensitive 1eNp0π channel is below the prediction and consistent with no excess. In the less sensitive 1e0p0π channel the observation at low energy is above the prediction, while overall there is agreement over the full energy spectrum.

New CC0π GENIE Model Tune for MicroBooNE

“…Further data-driven model constraints will often be essential for achieving sufficient precision. However, based on the overall improvement seen in the description of MicroBooNE data across many event selections and observables, the collaboration has adopted the "MicroBooNE Tune" described herein as the base neutrino interaction model for all current analyses, including those investigating the MiniBooNE LEE [10][11][12][13]40] and neutrino-argon cross sections [41,42].…”

“…In this article, we present a tune of the GENIE [5] v3.0.6 G18 10a 02 11a CCQE and CC2p2h models to T2K CC0π cross-section data [9]. The main purpose of this work is to provide an important input to the ν efocused MicroBooNE LEE analyses [10][11][12][13]. One of the primary goals there is to use the ν µ data to constrain the ν e model with robust uncertainties and covariances.…”

Hot New Early Dark Energy: Towards a Unified Dark Sector of Neutrinos, Dark Energy and Dark Matter

“…This then allows for the presence of a fourth eV mass eigenstate ν 4 mainly composed of sterile neutrinos. It has been claimed [56][57][58] that the presence of ν 4 can resolve different anomalies seen in accelerator [68,69], reactor [70] and gallium experiments [71,72], although the role of steriles in resolving these discrepancies is currently debated [73][74][75]. However, if ν 4 equilibrates with the active neutrinos in the early universe, this proposal runs into problems with cosmological bounds on N eff .…”

Investigating Leggett-Garg inequality in neutrino oscillations -- role of decoherence and decay

“…In addition, we should also mention that there are some unresolved anomalies of high statistical significance, notably the event excesses seen in LSND (3.8σ excess of ν e events) [4], Mini-BooNE (4.7σ excess of ν e events and 2.7σ excess of νe events) [5,6], along with the so-called reactor antineutrino anomaly (6% flux deficit) [7] which point towards existence of eV scale sterile neutrinos. The source of the excess of events seen in MiniBooNE has been further investigated by MicroBooNE [8][9][10] which reports no such excess.…”