Future SK- -Experiments Experiments Future SK US-Japan Seminar ‘ ββ Decay and ν Mass’ Michael Smy Kapalua, Maui, September 2005 UC Irvine
Solar Neutrinos Solar Neutrinos Michael Smy, UC Irvine
Solar MSW- -Vacuum Transition Vacuum Transition Solar MSW SSM spectrum pp 0.8 Vacuum osc. 0.8 P( ν e � ν e ) dominant 7 Be 0.6 0.6 Expected P( ν e � ν e ) pep 0.4 0.4 8 B 0.2 0.2 matter osc. dominant Courtesy of M. Nakahata, ICRR
Expected low energy upturn ( 8 B) SK ( ν e scattering) SNO CC ∆ m 2 =8.3x10 -5 eV 2 ∆ m 2 =8.3x10 -5 eV 2 sin 2 ( θ ) 0.22 Arbitrary unit 0.28 0.35 sin 2 ( θ )=0.28 sin 2 ( θ )=0.28 ∆ m 2 (eV 2 ) 9.1 x 10 -5 current threshold current threshold Arbitrary unit 8.3 x 10 -5 7.4 x 10 -5 Total energy ~20% in SNO and ~10% in SK distortion is expected from 4 MeV to 15 MeV Courtesy of M. Nakahata, ICRR
Atmospheric Neutrinos Atmospheric Neutrinos • L/E Oscillation Analysis • Three Flavor Oscillations • Appearance of τ leptons Michael Smy, UC Irvine
Similar plot with this selected subset: (~2700 events) Preliminary decoherence decay best-fit osc (favored by >3 σ ) "the dip" Seems to be really wiggling! Courtesy of K. Scholberg, Duke University
L/E Analysis L/E Analysis SK I Analysis SK II Analysis Preliminary Courtesy of K. Scholberg, Duke University
θ 13 Zero θ Look for Non- -Zero in Look for Non 13 in ν e Enhancement of ν for some Angles/Energies Enhancement of e for some Angles/Energies Normal hierarchy: resonance for neutrinos 2 , sin 2 2 2 m 0.003 eV 0.5,sin 0.026 23 13 matter co s 0.6 P( ν µ → ν e ) enhancement P( ν e → ν µ ) P( ν e → ν e ) P( ν µ → ν µ ) GeV P( ν µ → ν e ) Courtesy of K. Scholberg, Duke University
Enhancement of Upgoing Upgoing Multi Multi- -GeV GeV Single Single Enhancement of Ring Electrons Ring Electrons Single-ring electrons (2.5<P<5.0GeV) ∆ m 2 = 0.002 eV 2 SK 20 years sin 2 θ 23 = 0.5 sin 2 θ 13 = 0.05 Positive ∆ m 2 Negative ∆ m 2 Null oscillation cos θ Courtesy of K. Scholberg, Duke University
Accelerator Accelerator Neutrinos Neutrinos KAMIOKA JAERI KEK TOKYO NARITA J-PARC Courtesy of T. Kobayashi, KEK
T2K: Search for ν ν µ ν e � ν µ � Appearance T2K: Search for e Appearance Main Main CP-odd Solar Matter Matter ν µ → ν δ � −δ , a � -a for Matter eff.: e ρ E = × − ⋅ ⋅ 5 2 a 7 . 56 10 [eV ] 3 [ g cm ] [ GeV ] − ∆ θ 2 sin 2 P P m L ≡ ≈ ⋅ ⋅ δ 12 12 sin A CP + θ sin P P E 13 θ 13 . from θ # of signal ∝ sin 2 θ 13 (Stat err ∝ sin θ 13 ), Sensitivity indep indep. from Sensitivity 13 CP-odd term ∝ sin θ 13 (if no BG & no syst syst. err) . err) (if no BG & no Courtesy of T. Kobayashi, KEK
T2K T2K J-PARC (Tokai-mura) Kamioka • (0.75MW � )4MW 50GeV PS @ J-PARC • Off-axis (OA) 2~3 0 : E ν peak =0.5 ~0.8GeV • L=295km Courtesy of T. Kobayashi, KEK
Off- -Axis: High Intensity Narrow Band Beam Axis: High Intensity Narrow Band Beam Off Far Det. (ref.: BNL-E889 Proposal) ν µ flux Target HornsDecay Pipe θ Decay Kinematics E ν (GeV) OAB2.0deg OAB2.5deg OAB3.0deg 1 5 E π (GeV) 1 / γ π ~ θ � Increase statistics @ osc. max. � Decrease background from HE tail Courtesy of T. Kobayashi, KEK
θ 13 Sensitivity for θ Sensitivity for 13 sin 2 2 θ 13 ~0.018 (3 σ ) sin 2 2 θ 13 ~0.006 (90%) 0.5xsin 2 2 θ 13 3 can be searched if θ 13 2 θ 2 2 -3 sin 2 < 10 - can be searched if syst syst err ~ few % err ~ few % sin 13 < 10 Courtesy of T. Kobayashi, KEK
Supernova/Reactor Neutrinos Supernova/Reactor Neutrinos • Rests on Identification of Antineutrinos • Beacom/Vagins: Neutrons from inverse β reaction capture on dissolved Gadolinium and produce detectable γ cascade (i.e. enough Č -light for SK) • Needs very low threshold • Feasibility study: detector corrosion, water purification, water transparency • MC simulation of reactor neutrino interactions Michael Smy, UC Irvine
Neutron Detection in SK: 0.1% GdCl 3 Neutron Detection in SK: 0.1% GdCl 3 γ ’s with Σ E=8MeV Gd ” could collect could collect “Super Super- -KamLAND KamLAND” “ this much data in two weeks this much data in two weeks ν e Antineutrino Spectrum 10 3 -1 SK with GdCl 3 dN/dE e [(22.5 kton) yr MeV] 10 2 Reactors From Beacom/Vagins PRL 93 171101,2004 10 1 Supernovae Atmospheric ( µ) (e) 10 0 10 -1 10 -2 0 5 10 15 20 25 30 35 40 Michael Smy, UC Irvine Measured E e [MeV]
Choubey and Petcov consider the reactor signal of SK-Gd Courtesy of M. Vagins, UCI
Gd MC: Input Spectrum MC: Input Spectrum Gd γ line Percentage for each γ line Percentage for each MeV MeV Michael Smy, UC Irvine
Event Reconstruction Event Reconstruction Gd ν e MC ( 3 MeV e + ) reconstr. reconstr. Gd vertex e + vertex distance true e + distance in cm vertex in cm true Gd vertex keep reconstr. e + vertex distance reconstr. in cm Gd n capture Michael Smy, UC Irvine
Shape of Gd Gd Events Events Shape of “Patlik” variable to remove residual βγ • Reconstructed Cherenkov Angle • spallation events from solar ν sample • Disadvantage: already used as a • Disadvantage: needs direction from “guideline” for the vertex low energy direction fit, which assumes reconstruction (of only e + ) i.e. a single e-like Cherenkov Ring distribution uses prior knowledge e + events e + events Gd events Gd events Michael Smy, UC Irvine
Shape of Gd Gd Events Events Shape of “Patlik” variable to remove residual βγ • Reconstructed Cherenkov Angle • spallation events from solar ν sample • Disadvantage: already used as a • Disadvantage: needs direction from “guideline” for the vertex low energy direction fit, which assumes reconstruction (of only e + ) i.e. a single e-like Cherenkov Ring distribution uses prior knowledge e + events e + events Gd events e + events Gd events Gd events Michael Smy, UC Irvine
New Super- -K K- -Water Purification System Water Purification System New Super remove 99.9% of Gd remove 80% of U in single pass No Gd No U/Th Gd 0.1% Gd 0.1% Gd SK Tank Final Polish RO Pretreatment (Gd Trapping Components) (Gd Passing Components) Courtesy of M. Vagins, UCI
October 2005: Test using K2K’ ’s Near Detector s Near Detector October 2005: Test using K2K K2K’s 1 kiloton tank is available for large-scale studies of • Gd Water Filtering – UCI built and maintains this water system • Gd Light Attenuation – using real 20” PMTs • Gd Materials Effects – many similar detector elements as in SK Courtes y of M. Va gins, UCI
Correlated Correlated (Background- -) ) (Background Events in SK- -I I Events in SK Michael Smy, UC Irvine
all after prompt E cut after timing cut all after vertex cut after vertex cut All cuts all after prompt E cut all after prompt E, after ∆ t cut vertex cut after delayed All E cut cuts Michael Smy, UC Irvine
Conclusion Conclusion • Hope to see distortion of solar ν recoil e - spectrum in SK-III • Gain more statistics for atmospheric L/E analysis • Search for ν e appearance with intense beam • Plan to add neutron detection to SK-III for reactor ν ’s, SN relic ν ’s Michael Smy, UC Irvine
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