Status and Perspectives of Short Baseline Studies Mark Dierckxsens University of Chicago TAUP 2009 July 1-5, 2009
Neutrino Oscillations Pontecorvo-Maki- = U 3 3 Nakagawa-Sakata Matrix: e 1 U e 1 U e 2 U e 3 U 1 U 2 U 3 2 3 mixing angles ⇨ 1 CP phase U 1 U 2 (2 CP Majorana phases) 1 cos 13 U = cos 23 − i cos 13 sin 13 e cos 12 sin 12 1 0 0 0 0 cos 23 sin 23 − sin 12 cos 12 0 1 0 0 0 i − sin 13 e − sin 23 0 0 0 0 solar atmospheric o o 23 ≈ 45 12 ≈ 34 θ 13 < 11 o 2 ∣ ≈ 2.4 10 2 ≈ 7.7 10 ∣ m 31 − 3 eV 2 − 5 eV 2 m 21 (90%CL) Many experiments (almost) all show consistent picture TAUP 2009, July 1-5 2009 2 Mark Dierckxsens
Neutrino Oscillations sin 2 θ 13 : e in 3 ● Unknowns of neutrino oscillations: ● θ 13 ? 2 0 m 31 2 0 m 31 ● δ cp ? ● mass hierarchy? 2 m 21 combination of all neutrino data Fogli et al arXiv:0905.3549 ● First hints of non-zero θ 13 ? ● Reactor neutrino experiments under construction will be probing well into this region See talk A. Palazzo sin 2 2θ 13 = 0.08 TAUP 2009, July 1-5 2009 3 Mark Dierckxsens
Measuring θ 13 at reactors ● Measure survival probability of e from nuclear reactor: 2 2 2 1.27 L m 31 2 1.27 L m 21 2 2 13 sin 4 13 sin 2 2 12 sin P e e ≈ 1 − sin − cos E E L in m, E in MeV Δm 2 in eV 2 ● for E ν = 4 MeV: 1 st maximum at ~2km (@ Δm 31 2 =2.5 10 -3 eV 2 ) subdominant ● Clean measurement of θ 13 : θ 13 oscillation ● weak dependance on solar parameters at low L/E dominant θ 12 oscillation ● no CP effects ● negligible matter effects TAUP 2009, July 1-5 2009 4 Mark Dierckxsens
Previous Experiments ● Many reactor experiments at various distances KamLAND PL B466:415-430 (1999) PRL 90, 021802(2003) Δm 2 (eV 2 ) CHOOZ e x Experiment sin 2 2θ 13 < 0.16 (90% CL) PRD 64:112001(2001) sin 2 2θ TAUP 2009, July 1-5 2009 5 Mark Dierckxsens
Improving CHOOZ Statistical Error on R=obs/exp Systematic 2.8% CHOOZ 2.7% increase reduce statistics systematics ● Identical detector close to reactor: ● Larger detector ● ratio measurement eliminates ● Longer running time cross section, neutrino flux & ● More powerful some detector uncertainties reactors ● Improved detector design: ● lower threshold, better efficiencies, detailed calibration program ● Lower background: ● better veto, shielding, overburden & radio-purity TAUP 2009, July 1-5 2009 6 Mark Dierckxsens
Experiments Under Construction Power Distance Target Experiment (GWth) N/F (m) N/F (t) Double 8.6/8.6 8.6 400/1050 Chooz RENO 17.3 290/1380 16/16 11.6 360(500)/ Daya Bay 1990(2620) 2x40/80 (17.4) TAUP 2009, July 1-5 2009 7 Mark Dierckxsens
Neutrinos from Reactors K. Schreckenbach et al., PL B 160 (1985) 325 ; ● ν e produced through beta A.A. Hahn et al., PL B 218 (1989) 365. decays of fission products 3.6 GW th ν e spectrum from measured β spectrum ● β spectrum from 235 U, 239/241 Pu measured to 1.8% ● Conversion results in error of 2.5-4% ● Improved conversion calculations ● I sotropic & pure source and planned measurement of 238 U of ~2 10 20 ν e /GW th /s will improve uncertainty TAUP 2009, July 1-5 2009 8 Mark Dierckxsens
Detection Technique ● Inverse beta decay: n e p e E th = 1.8 MeV <E ν > ~ 4 MeV γ γ γ e + ν e γ p Gd/H n γ ● Gd doped liquid scintillator: ● Prompt e + annihilation: E vis ≃ E – 0.8 MeV ● Delayed γ s from n capture by: Gd:Δt ~ 30μs, E ~ 8 MeV σ = 49000b H: Δt ~ 200μs, E ~ 2.2 MeV σ = 0.3b ● Liquid scintillator: capture escaping γ s ● Non-scintillating buffer region contains PMTs TAUP 2009, July 1-5 2009 9 Mark Dierckxsens
Backgrounds Accidental background + neutron like signal e like signal AND n generated by cosmic μ, radioactivity from PMTs, γ mimicking n signal materials, rock Correlated background Fast neutrons: produced by cosmic μ recoil p + Gd capture OR Long lived isotopes 9Li (8He, 11Li): β-n decay τ ~ 100ms TAUP 2009 , July 2009 5 - 1 10 Mark Dierckxsens
Double Chooz Experiment Near 8.6t Far 8.6t overbdn 45m overbdn 110m 1050m 400m Chooz-B Power Plant ● 2 cores, 8.6 GW th TAUP 2009, July 1-5 2009 11 Mark Dierckxsens
Status of Double Chooz Far hall ● Far detector under construction ● Buffer PMTs installed last month, acrylic vessels integration started ● Phase I: data taking with far detector only from spring 2010 ● Near lab will be available at end of 2010 ● Phase II: data taking with both detectors in 2011 See talk J. Maricic Far PMTs TAUP 2009, July 1-5 2009 12 Mark Dierckxsens
RENO Experiment Near 20t 70m overbdn 290m 1380m YeongGwang Power Plant Far 20t 200m overbdn ● 6 cores, 17.3 GW th TAUP 2009, July 1-5 2009 13 Mark Dierckxsens
Status of RENO ● Near & far tunnels completed Tunnel entrance ● Oct 2009: Steel/acrylic vessels & support installation ● Early 2010: both detectors ready for data taking ● Test mock-up detector (1/10) ongoing Mock-up detector Detector pit Provided by Soo-Bong Kim TAUP 2009, July 1-5 2009 14 Mark Dierckxsens
Daya Bay Experiment Far 4x20t overbdn 355m 1615m LA Near 2x20t overbdn 112m 1985m Ling Ao II (2011) DYB Near 2x20t DYB Near 2x20t overburden: 95m overbdn: 95m Ling Ao Daya Bay/Ling Ao Power Plant HONG KONG Daya Bay ● 4 cores, 11.6 Gw th ● 2011: 6 cores, 17.4 GW th TAUP 2009, July 1-5 2009 15 Mark Dierckxsens
Status of Daya Bay Tunnel Assembly building ● March 2009: surface assembly building Acrylic occupancy vessel ● Summer 2009: DB near hall occupancy ● Fall 2009: first detector ready ● Summer 2010: DB near hall ready for data ● Summer 2011: far hall ready for data See talk K. Heeger TAUP 2009, July 1-5 2009 16 Mark Dierckxsens
Expected Sensitivities 31 (x10 -3 ) 90% CL RENO Double Chooz sin 2 2θ 13 Near & Far Δm 2 Far only sin 2 2θ 13 Exposure time (years) 90% CL σ stat σ syst rel. sin 2 2θ 13 > Expt [%] [%] (90% CL) Double 0.5 0.6 0.03 Chooz Daya Bay RENO 0.5 0.02 0.3 Daya Bay 0.4 0.01 0.2 sin 2 2θ 13 TAUP 2009, July 1-5 2009 17 Mark Dierckxsens
LSND Experiment ● E = 20-55 MeV, L = 30m Aguilar et al. PRD64:112007,2001 ● look for e in liquid scintillator detector ● excess over background: 87.9 ± 22.4 ± 6.0 ● 3.8σ evidence for oscillations ● L/E requires Δm 2 very different from solar and atmospheric Δm 2 ● 3 mass differences requires mixing with a 4 th type of neutrino with different mass: evidence for sterile neutrinos? TAUP 2009, July 1-5 2009 18 Mark Dierckxsens
MiniBooNE Experiment ● Same L/E as LSND but different neutrino-mode flux experimental environment GEANT4 sim ● <E > = 700MeV, L = 500m ~ 6% ● 800t mineral oil Čerenkov detector e ~ 0.5% ● protons-on-target collected: ● 6.5 10 20 PoT in neutrino mode ● 5.1 10 20 PoT in anti-neutrino mode; approved for 5 10 20 PoT more target and horn decay region absorber dirt detector e K + + Booster 8.9GeV See talk M. Shaevitz primary beam secondary beam tertiary beam (protons) (mesons) (neutrinos) TAUP 2009, July 1-5 2009 19 Mark Dierckxsens
e A.A. Aguilar-Arevalo et al. ● Full data sample analyzed PRL 98, 231801 (2007); PRL 102, 101802 (2009) (6.5 10 20 PoT) ● Select charged current quasi-elastic e interactions ● No excess of events in LSND signal region (>475 MeV) ● Ruled out 2 oscillations as source of LSND signal (if no CP & CPT violation) TAUP 2009, July 1-5 2009 20 Mark Dierckxsens
e at Low Energies ● Excess of events at low energy: 128.8 ± 20.4 ± 38.3 (3.0σ) ● Shape not consistent with 2 oscillations ● Magnitude consistent with LSND ● Observed with NuMI neutrinos. Results with more data and improved errors underway. P. Adamson et al., PRL 102, 211801 (2009) TAUP 2009, July 1-5 2009 21 Mark Dierckxsens
e ● Direct test of LSND ● First result with 3.4E20 PoT ● No excess above expectations: ● 200-475 MeV: -0.5 ± 11.7 events ● 475-1250 MeV: 3.2 ± 10.0 events ● 3x data sample expected A.A. Aguilar-Arevalo et al., arXiv:0904.1958 [hep-ex] TAUP 2009, July 1-5 2009 22 Mark Dierckxsens
μ and μ disappearance ● Set limits in unexplored parameter space for μ and μ disappearance ● Update incorporating SciBooNE data underway (SciBooNE is a fine-grained tracking detector ~100m from the target which took data from June 2007 until August 2008) A.A. Aguilar-Arevalo et al., arXiv:0903.2465 [hep-ex] TAUP 2009, July 1-5 2009 23 Mark Dierckxsens
MicroBooNE ● LArTPC detector: advance LAr R&D and investigate MiniBooNE low-energy excess (electrons or photons) & cross sections ● 70-ton fiducial volume, near MiniBooNE. ● Received Stage-1 approval at Fermilab and initial funding from DOE and NSF. ● May begin data taking as early as 2011. ● ArgoNeut: 170L LAr, currently taking data in NuMI beam DIS candidate See talk J. Spitz TAUP 2009, July 1-5 2009 24 Mark Dierckxsens
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