Results from MiniBooNE and SciBooNE
Users Meeting 2010 Joseph Walding College of William and Mary
2nd June 2010 Outline Joseph Walding Fermilab Users Meeting 2nd June 2010
● MiniBooNE and SciBooNE Refresher Course ● Physics Results From The Last Year... – Neutrino Cross-sections – Neutrino Oscillations ● Summary
2 MiniBooNE Collaboration Joseph Walding Fermilab Users Meeting 2nd June 2010
● University of Alabama ● Saint Mary's University of Minnesota
● Bucknell University ● Virginia Tech.
● University of Cincinnati ● Western Illinois University
● University of Colorado, Boulder ● Yale University
● Columbia University
● Embry-Riddle Aeronautical University
● Fermi National Accelerator Laboratory
● University of Florida
● University of Illinois
● Indiana University
● Los Alamos National Laboratory
● Louisiana State University
● MIT
● University of Michigan 3 ● Princeton University SciBooNE Collaboration Users Meeting 2010
● Universitat Autonoma de Barcelona ● Purdue University Calumet
● University of Cincinnati ● Universita degli Studi di Roma "La Sapienza" & INFN ● University of Colorado, Boulder ● Saint Mary's University of Minnesota ● Columbia University ● Tokyo Institute of Technology ● Fermi National Accelerator Laboratory ● Unversitat de Valencia ● High Energy Accelerator Research Organization (KEK)
● Imperial College London A selection of SciBooNE collaborators at the ● Indiana University London Collaboration Meeting. March 2008
● Institute for Cosmic Ray Research (ICRR)
● Kyoto University
● Los Alamos National Laboratory
● Louisiana State University
● MIT 4 Outline Joseph Walding Fermilab Users Meeting 2nd June 2010
● MiniBooNE and SciBooNE Refresher Course ● Physics Results From The Last Year... – Neutrino Cross-sections – Neutrino Oscillations ● Summary
5 The Booster Experiments Joseph Walding Fermilab Users Meeting 2nd June 2010
50 m 440 m
SciBooNE MiniBooNE
● Booster Proton accelerator: 8 GeV protons sent to target
● Target Hall: Beryllium target. 174kA magnetic horn with reversible horn polarity
● 50m decay volume: Mesons decay to & . Short decay pipe minimises e decay 6 ● SciBooNE: 100m baseline; MiniBooNE: 540m baseline Neutrino Beam Joseph Walding Fermilab Users Meeting 2nd June 2010
● Use HARP experiment pBeproduction data to predict our neutrino flux –
● Kaon production: Primary source of e's
● Reversible horn polarity used to sign select mesons – Run in neutrino or anti-neutrino mode
MiniBooNE Neutrino-Mode Flux MiniBooNE Antineutrino-Mode Flux ν ν µ ν µ µ
ν µ ν ν e e ν e ν e
7 Wrong sign flux: ~6% Wrong sign flux: ~18%
Intrinsic e flux: ~0.5% Intrinsic e flux: ~0.5% SciBooNE Joseph Walding Fermilab Users Meeting 2nd June 2010
SciBar Electron-Catcher (EC) 14,336 Scintillator bars 'Spaghetti' Calorimeter 15 tons (10 tons F.V.) 2 planes (x&y) 11X p/ separation using dE/dx 0 0 identify & e
Muon Range Detector (MRD) 12 2” iron planes 362 scintillator panels stop 's with p < 1.2 GeV/c
beam
All detectors have X&Y views SciBar & EC used at K2K 4m MRD 'new' detector built at FNAL 2008 DOE P2* Environmental Award 2m 8 MiniBooNE Joseph Walding Fermilab Users Meeting 2nd June 2010
Cherenkov Detector Specification
Events identified using: 12 m diameter tank Ring topology 900 tons mineral oil (CH2) -decay Michel signal 1280 inner PMTs (signal region) Scintillation light 240 outer PMTs (veto region)
Able to distinguish from e
Physics Goals:
Principally a neutrino oscillation experiment. Also able to measure neutrino cross-sections 9 Huge data-set in neutrino and antineutrino mode Data Sets Joseph Walding Fermilab Users Meeting 2nd June 2010
MiniBooNE SciBooNE
) 30 T O
P mode 6 1 E 4 /
( mode 20 _ e t
a _ r t mode n e mode v E 10 mode mode
0 J un J ul Oct Nov Dec J an Feb Mar Apr May J un J ul Aug '07 '08 Date 0 1 ● 20 2: 0.99x10 POT _ ● : 1.53x1020 POT ● : 6.5x1020 POT _ ● 95% POT efficiency ● : 5.8x1020 POT _ Thank you to the Beams Division! ● Currently running in mode 10 – Approved for 1x1021 POT Outline Joseph Walding Fermilab Users Meeting 2nd June 2010
● MiniBooNE and SciBooNE Refresher Course ● Physics Results From The Last Year... – Neutrino Cross-sections – Neutrino Oscillations ● Summary
11 Neutrino Cross-Sections Joseph Walding Fermilab Users Meeting 2nd June 2010 _ ● Previous measurements from ● No measurements of sub-GeV 1970's-1980's cross-sections
● Mostly H2 & D2 targets ● Important for CP studies _ ● Small sample sizes (100's of events) ● and Different oscillation probabilities _ CC cross-section G. Zeller CC cross-section G. Zeller
T2K NOvA T2K NOvA 12 LBNE LBNE Neutrino Cross-Sections Joseph Walding Fermilab Users Meeting 2nd June 2010 Good understanding of high E cross-sections (DIS) Low E is different regime: Quasi-elastic (QE) and single pion (1) events dominate Important for future neutrino oscillation experiments _ CC cross-section G. Zeller CC cross-section G. Zeller
T2K NOvA T2K NOvA 13 LBNE LBNE Neutrino Cross-Sections Joseph Walding Fermilab Users Meeting 2nd June 2010
Expected statistic error (T2K) K. Hiraide 5% systematic 20% systematic
Wish to know T2K cross-sections better than 10%
CC cross-section G. Zeller
quasi-elastic (QE) signal
NC π 0 (background to ν e appearance) CC π + T2K NOvA (background to 14 ν disappearance) LBNE µ Quasi-Elastic Scattering Joseph Walding Fermilab Users Meeting 2nd June 2010
'Typical' muon ring in MiniBooNE
CCQE W+
n p
● MiniBooNE uses muonkinematics to describe event
● Identify muons from decay signature
● Measuring total and differential cross- sections – Not ratios with respect to Charged 15 Current inclusive events Quasi-Elastic Scattering Joseph Walding Fermilab Users Meeting 2nd June 2010
eff 2 MA = 1.35 ± 0.17 GeV/c
cf. K2K: MA = 1.20 ± 0.12 (SciFi)
MA = 1.14 ± 0.11 (SciBar) ● Very different from light target experiments and for higher energy interactions
● First double differential CCQE cross-section – Model Independent 146,070 events: 77.0% purity, 26.6% efficiency J. Phys. Phys. J. G28 , R1, (2002)
16
T. Katori: arXiv:1002.2680, accepted by PRD Quasi-Elastic Scattering Joseph Walding Fermilab Users Meeting 2nd June 2010
'Typical' 2-track CCQE event in SciBooNE
CCQE W+
n p p
● SciBooNE uses muon and proton kinematics to describe event
● Identify muons using MRD or from decay signature
17 Quasi-Elastic Scattering Joseph Walding Fermilab Users Meeting 2nd June 2010
● Extraction of CCQE absolute cross-section J. Alcaraz – MRD-matched sample
MRD-Matched Sample: 13,585 1-track events: 66.2% purity, 10.8% efficiency 2,915 2-track events: 68.5% purity, 2.3% efficiency
Preliminary
SciBar-Contained SciBar-Contained 1-track sample 2-track sample
● SciBar-contained 1-track () sample: Excess in backwards muon tracks
● Not seen in 2-track (+p) sample
18 J. Walding: Thesis Quasi-Elastic Scattering Joseph Walding Fermilab Users Meeting 2nd June 2010
● SciBooNE and MiniBooNE data in good agreement ● Low to high energy discrepancy – Minerva to fill in the gaps... Minerva, MINOS
Preliminary
19 NC-Elastic Scattering Joseph Walding Fermilab Users Meeting 2nd June 2010
● Neutral Current – NCE Z0 SciBooNE: Proton track – MiniBooNE: Scintillation light
● Proton typically below n,p n,p Cherenkov threshold
● SciBooNE: – NC/CCQE ratio calculation in progress – watch this space!
20 NC-Elastic Scattering Joseph Walding Fermilab Users Meeting 2nd June 2010 d ● Extracted dQ2
● MiniBooNE CCQE value for MA better description of data than world average
● Isolating a Cherenkov proton sample – Ratio: p p / N N Preliminary – Strange spin component of the nucleon, s
● s= 0.08±0.26, systematics limited D. Perevalov: arXiv D. 0909.4617Perevalov:
Preliminary
Preliminary 21 NC Production Joseph Walding Fermilab Users Meeting 2nd June 2010
Z0
n,p n,p
● SciBooNE: Two measurements – Inclusive NC 0 – Coherent NC 0
22 Inclusive NC Production Joseph Walding Fermilab Users Meeting 2nd June 2010
● Charged current events rejected by looking for muon decay signature
● Vertex reconstruction used to reject external neutrino events (dirt events) from sample
● Able to reconstruct the 0 mass
● Extract_ model independent cross-section
ratio (E= 0.8 GeV): 657 events selected, 240 expected background events
0 0 0 NC NC NC N obs −N bck CC = CC CC CC − 0 N obs N bck NC Y. Kurimoto: Phys. Rev. D81, 033004 Kurimoto: Phys. Rev. Y. =7.7±0.5stat±0.5sys×10−2
cf. MC prediction = 6.8x10-2 23 Error < 10% Coherent NC Production Joseph Walding Fermilab Users Meeting 2nd June 2010 ν Without vertex activity µ ν µ π0
● Neutrino interacts coherently with whole nucleus – No nucleon recoil, forward tracks only – SciBar sensitive to proton recoil
● Not possible in MiniBooNE With vertex activity ● Define region around reconstructed vertex to look for proton recoil activity
● Extract model-dependent coherent fraction
● Fraction of NC π0 events from coherent channel: 17.9% (cf. MiniBooNE: 19.5%) – Agrees with Rein-Sehgal (RS) prediction – CC (K2K, SciBooNE): No evidence of coherent 24
production - disagrees with RS prediction by PRD accepted Kurimoto: arXiv 1005.0059, Y. MB: NC Production Joseph Walding Fermilab Users Meeting 2nd June 2010
Z0
n,p n,p
● Cross-section extraction in neutrino and antineutrino mode
25 MB: NC Production Joseph Walding Fermilab Users Meeting 2nd June 2010
● More model-independent measurements _ ● Flux averaged differential cross-sections (and mode) – Already being used by T2K!
26 C. Anderson: Phys. Rev. D81, 013005 CC Production Joseph Walding Fermilab Users Meeting 2nd June 2010
● + CC- : Background to disappearance – If pion not identified event looks W+ CCQE-like – Mis-reconstruction of neutrino energy n,p n,p ● For T2K need to know CC-+ cross- section to <10%
● CC-0: Not an oscillation background – Completes production picture
27 MB: CC Production Joseph Walding Fermilab Users Meeting 2nd June 2010
● Ability to separate pion and muon tracks Kink point – Hadronic interactions kinked tracks
● Absolute and multiple differential cross-sections calculated:
Model ∂ ∂ ∂ ∂ ∂2 ∂2 Independent , , , , , ∂KE ∂cos ∂KE ∂ cos ∂ KE ∂cos ∂KE∂cos
Model ∂ E , dependent ∂Q2
Preliminary Preliminary M. Wilking M. Wilking 28 MB: CC Production Joseph Walding Fermilab Users Meeting 2nd June 2010
R. Nelson ● 3-ring fitting required – Overlapping, difficult to distinguish Preliminary ● Identify muon ring
● Reconstruct pion mass from photon rings
● Construct and cut on CC0 vs. R. Nelson generic 3-track fit likelihood difference
Preliminary
29 Plots: Absolute normalisation MB: CC Production Joseph Walding Fermilab Users Meeting 2nd June 2010
● Absolute and several differential cross- sections extracted
● MC not in agreement with measurement Preliminary
R. Nelson
Preliminary Preliminary R. Nelson
R. Nelson 30 SB: CC Production Joseph Walding Fermilab Users Meeting 2nd June 2010
● Analysis currently in progress – Successfully reconstructed pion mass ● Goal: Calculate absolute cross-section
Preliminary
J. Catala
31 Plot: MRD-Matched Normalisation Outline Joseph Walding Fermilab Users Meeting 2nd June 2010
● MiniBooNE and SciBooNE Refresher Course ● Physics Results From The Last Year... – Neutrino Cross-sections – Neutrino Oscillations ● Summary
32 MiniBooNE Oscillations Joseph Walding Fermilab Users Meeting 2nd June 2010
ν e Appearance Phys. Rev. Lett. 98, 231801 (2007)
ν µ Disappearance Phys. Rev. Lett. 103, 061802 (2009)
ν e Appearance Phys. Rev. Lett. 103, 111801 (2009)
ν µ Disappearance Phys. Rev. Lett. 103, 061802 (2009)
33 _ _ MB: e Appearance Joseph Walding Fermilab Users Meeting 2nd June 2010
● Direct test of LSND signal
● Analysis based on 3.386x1020POT
● 200-475 MeV: -0.5 ± 11.1 events
● 475-1250 MeV: 3.2 ± 10.0 events – No indication of data-MC excess 34 Result inconclusive with respect to LSND _ _ MB: e Appearance Joseph Walding Fermilab Users Meeting 2nd June 2010
? ? th June and Neutrino 2010
See W&C 14 Updated MiniBooNE anti-neutrino result coming... 35 Kaon Production Joseph Walding Fermilab Users Meeting 2nd June 2010
● Kaon production in beam corresponds to
intrinsic e in neutrino beam
● Major source of uncertainty for the
MiniBooNE e appearance measurement
0 – K e e (BR: 5%)
– + Constrain K flux from high energy events MiniBooNE Collaboration: Phys. Rev. D79, 072002 (2009)
● Data/MC ratio:
– 0.35 2-Track sample: 0.74±0.06(stat.)± 0.26(sys.) (preliminary)
– 0.35 3-Track sample: 0.77±0.08(stat.)± 0.27 (sys.) (preliminary)
36 G. analysis Cheng SB+MB Disappearance Joseph Walding Fermilab Users Meeting 2nd June 2010
Y. Nakajima ● First inter-collaboration measurement!
● Improve disappearance measurement – Use SciBooNE as a near detector – Same nuclear target (Carbon)
● Reduce uncertainties
– Beam flux Preliminary
● Improved from MiniBooNE-only sensitivity especially at low-Δm2 region, where absolute normalisation is important.
Final data fit result will be released soon! 37 MB: Supernova Search Joseph Walding Fermilab Users Meeting 2nd June 2010
● Search for supernova from Dec. 14th 2004 – July 31st 2008 – 98% detector live-time
● No observation of supernova within the Milky Way galaxy is observed to a distance of 13.5kpc – Limit set to 0.69 supernova per year inside 13.5kpc (90% CL)
38 M. Fisher, H. Ray: Phys. Rev. D81, 032001 Papers and Theses Joseph Walding Fermilab Users Meeting 2nd June 2010
● SciBooNE: – Papers
● NC Inclusive 0: Phys. Rev. D81, 033004 ● NC Coherent 0: arXiv:1005.0059 (accepted to Phys. Rev. D) – Theses: Y. Kurimoto, J. Walding ● MiniBooNE: – Papers
● CCQE: arXiv: 1002.2680 (accepted to Phys. Rev. D) ● NC0: Phys. Rev. D81, 013005 ● CC+/QE ratio: Rev. Lett. 103, 081801 ● MiniBooNE Supernova Search: Phys. Rev. D81, 032001
– Theses: D. Perevalov, R. Nelson 39 Summary Joseph Walding Fermilab Users Meeting 2nd June 2010
● A number of new cross-section results from both experiments published or in the pipeline – Many firsts! – Model-independent differential cross-sections – Interesting kinematic distributions ● First joint SB+MB Analysis: Paper in the works
40 Thank you!
41 Backup
42 SciBooNE Event Definition Joseph Walding Fermilab Users Meeting 2nd June 2010
● Three event sub-categories
SciBar-Contained MRD-not-Stopped MRD-Stopped Sample Sample Sample SciBar EC MRD SciBar EC MRD SciBar EC MRD
MRD-Matched Sample 43 Quasi-Elastic Scattering Joseph Walding Fermilab Users Meeting 2nd June 2010
● SB-contained 1-track () sample: Excess in backwards muon tracks
● Not seen in 2-track (+p) sample
● Mis-reconstruction – Short tracks – High angle tracks
● Not the case, looks to be real physics – Under further investigation
● Timing comparison between track ends supports case for physics effect 44 Instrumental effect Inclusive NC Production Joseph Walding Fermilab Users Meeting 2nd June 2010
Nobs 657
NBG 240 ε NCπ0 0.05 CC N obs 21702 CC N BG 2348 ε CC 0.19
45 46 MB: NC Production Joseph Walding Fermilab Users Meeting 2nd June 2010
● Data in agreement with MC including coherent production for _ both and mode – Angular distribution – Total cross-section
● Consistent with SciBooNE result
47