Beyond Standard Model Searches in the MiniBooNE Experiment

Abstract

The MiniBooNE Experiment has contributed substantially to beyond standard model searches in the neutrino sector. The experiment was originally designed to test the ∆m 2 ∼ 1 eV 2 region of the sterile neutrino hypothesis by observing ν e (ν e ) charged current quasi-elastic signals from a ν µ (ν µ ) beam. MiniBooNE observed excesses of ν e andν e -candidate events in neutrino and anti-neutrino mode, respectively. To date, these excesses have not been explained within the neutrino Standard Model (νSM), the Standard Model extended for three massive neutrinos. Confirmation is required by future experiments such as MicroBooNE. MiniBooNE also provided an opportunity for precision studies of Lorentz violation. The results set strict limits for the first time on several parameters of the Standard Model-Extension, the generic formalism for considering Lorentz violation. Most recently, an extension to MiniBooNE running, with a beam tuned in beam-dump mode, is being performed to search for dark sector particles. This review describes these studies, demonstrating that short baseline neutrino experiments are rich environments in new physics searches. 1 arXiv:1404.7759v1 [hep-ex] 30 Apr 2014Across the particle physics community, the mysterious periodic-table-like nature of the Standard Model (SM) is motivating searches for new particles, new forces and new properties of the particles that are known. The neutrino sector is proving a rich environment for these searches. Having already found one beyond-Standard-Model (BSM) effect-neutrino mass [1]-a series of experiments are pursuing other potential signals. Unlike the case of three-neutrino oscillation measurements within νSM, many of these searches are pursued over short baselines, from a few meters to approximately a kilometer. The Mini Booster Neutrino Experiment (MiniBooNE) at Fermi National Accelerator Laboratory (Fermilab) is an excellent example, having contributed substantially to BSM studies.This review describes the MiniBooNE BSM program. We begin by describing the experiment. This is followed by a discussion of the MiniBooNE cross section studies, which have been essential input to both the BSM searches within this experiment, and also to other experiments, including T2K most recently [2]. We then describe three searches: the sterile neutrino search which motivated the experiment, Lorentz violation searches which set the first limits on five neutrino sector parameters, and the search for dark sector particles which is now being pursued with a re-configured beam. MiniBooNE (running from 2002MiniBooNE (running from -2012 was originally designed to test the LSND signal [3]. In the LSND experiment, low energy (0 to 53 MeV) muon anti-neutrinos were produced by pion decayat-rest (DAR), and were detected by the liquid-scintillator-based LSND detector at 31 m from the target. The observed 3.8σ excess ofν e candidate events could be interpreted as oscillations in the ∆m 2 ∼ 1 eV 2 region within a simple two massive neutrino oscillation hypothesis, where the oscillation proba...

Light sterile neutrinos

“…[111], in which the anomalous MiniBooNE low-energy excess of ν e -like events is neglected. The cause of this excess is going to be investigated in the MicroBooNE experiment at Fermilab [216][217][218].…”

“…The cause of the MiniBooNE low-energy excess of ν e -like events is going to be investigated in the MicroBooNE experiment at Fermilab [216,217], which is a large Liquid Argon Time Projection Chamber (LArTPC) in which electrons and photons can be distinguished 16 (see the review in Ref. [218]). In the following we adopt the "pragmatic approach" advocated in Ref.…”

Weak neutral current axial form factor using $$ \left(\overline{\nu}\right)\nu $$-nucleon scattering and lattice QCD inputs

“…This effect was already included in the NUANCE Monte-Carlo JHEP01(2020)136 simulation and shown to have an impact exactly in the Q 2 0.15 GeV 2 region [83,84]. A further possible reason is nuclear shadowing which is related to the phenomenon that, at low Q 2 , the resolution is not sufficient to resolve a single nucleon wave function and therefore the differential cross section dσ/dQ 2 decreases [85]. We use the average beam energy E ν = 0.80 GeV and E ν = 0.65 GeV in eq.…”

Weak Neutral Current Axial Form Factor Using $(\barν)ν$-Nucleon Scattering and Lattice QCD Inputs

“…This was already included in the NUANCE MC simulation and shown to have impact exactly in the Q 2 0.15 GeV 2 region [67,68]. A further possible reason is nuclear shadowing which is related to the phenomenon that at low Q 2 , the resolution is not sufficient to resolve a single nucleon wave function and therefore dσ/dQ 2 decreases [69]. To demonstrate the importance of a correct determination of G Z A (Q 2 ), we show in Fig.…”