Dual baseline search for muon antineutrino disappearance at0.1  eV2<Δm2<100  eV2

Abstract

The MiniBooNE and SciBooNE collaborations report the results of a joint search for short base-43 line disappearance ofνµ at Fermilab's Booster Neutrino Beamline. The MiniBooNE Cherenkov 44 detector and the SciBooNE tracking detector observe antineutrinos from the same beam, therefore 45 the combined analysis of their datasets serves to partially constrain some of the flux and cross sec-46 tion uncertainties. Uncertainties in the νµ background were constrained by neutrino flux and cross 47 section measurements performed in both detectors. A likelihood ratio method was used to set a 48 90% confidence level upper limit onνµ disappearance that dramatically improves upon prior limits 49 in the ∆m 2 =0.1-100 eV 2 region.Recently there has been increasing evidence in sup-2 port of neutrino oscillations in the ∆m 2 ≈ 1 eV 2 re-3 gion. The LSND [1] experiment observed an excess of 4ν e -like events in aν µ beam. MiniBooNE [2-4] has ob-5 served an excess of ν e -like andν e -like events, in a ν µ 6 beam andν µ beam, respectively. Additional evidence for 7 short-baseline anomalies with L/E ≈ 1, where L is the 8 neutrino path length in km and E the neutrino energy 9 in GeV, includes the deficit of events observed in reac-10 tor antineutrino experiments [5] and radioactive source 11 neutrino measurements [6]. If these anomalies are due 12 to neutrino oscillations in the ∆m 2 ≈ 1 eV 2 range, then 13 they could imply the existence of one or more new ster-14 ile neutrino species that do not participate in standard 15 weak interactions but mix with the known neutrino fla-16 vors through additional mass eigenstates. Observation 17 of ν µ (ν µ ) disappearance in conjunction with ν e (ν e ) ap-18 pearance in this ∆m 2 range would be a smoking-gun for 19 the presence of these sterile neutrinos. Alternatively, con-20 straining ν µ (ν µ ) disappearance can, along with global ν e 21 (ν e ) disappearance data, constrain the oscillation inter-22 pretation of the ν e (ν e ) appearance signals in LSND and 23 MiniBooNE [7]. 24 Searches for ν µ andν µ disappearance in MiniBooNE 25 were performed in 2009 [8]. No evidence for disappear-26 ance was found. The search for ν µ disappearance was 27 recently repeated in MiniBooNE with the inclusion of 28 data from the SciBooNE detector in a joint analysis [9]. 29 Once again, the results were consistent with no ν µ dis-30 appearance. The analysis presented here is an improved 31 search forν µ disappearance using data from MiniBooNE 32 12 mented scintillator tracker (SciBar), an electromagnetic 13 calorimeter (EC), and a muon range detector (MRD).14 The SciBar subdetector [13] consists of 14336 extruded 15 polystyrene (C 8 H 8 ) strips arranged vertically and hor-16 izontally to construct a 3 × 3 × 1.7m 3 volume. Each 17 scintillator strip is read out by a wavelength shifting 18 fiber attached to a 64-channel multianode PMT (MA-19 PMT). The 15 ton SciBar subdetector (10.6 ton fiducial 20 FIG. 3. Schematic view of the MiniBooNE detector. volume) provides the primary interaction target. The 1 EC subde...

Relativistic description of final-state interactions in neutral-current neutrino and antineutrino cross sections

“…The results on neutrino oscillations published by different collaborations [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] have raised a large debate over the properties of neutrinos that could lead to a more complete understanding of neutrino physics. Because of the interest in oscillation measurements, various experimental neutrinonucleus differential cross sections have been presented [16][17][18][19][20][21] and are planned in the near future [22][23][24].…”

Search for a Light Sterile Neutrino at Daya Bay

“…The LSND [15] and MiniBooNE [16,17] experiments observed excesses of electron (anti-)neutrino events in their muon (anti-)neutrino beams, which could be interpreted as sterile neutrino oscillation with jΔm 2 j ∼ 1 eV 2 . However, these results are in tension [18][19][20][21] with the limits derived from other appearance [22][23][24][25] or disappearance searches [26][27][28][29][30][31][32][33][34][35][36]. Moreover, a reanalysis of the measured vs predicted electron antineutrino events from previous reactor experiments has revealed a deficit of about 6% [37,38].…”

Searches for sterile neutrinos with IceCube

“…The difference between the effective matter potentials for sterile and active neutrinos and the mantle-core-mantle profile of the Earth result in a resonant enhancement of the (Right) The 90% C.L. exclusion limits (red solid line) obtained in the IceCube high energy sterile neutrino search and compared to the limits from previous experiments [18,19,20,21]. Green and yellow shaded areas represent 68% and 95% variations of the expected 90% C.L.…”