Future SK- -Experiments Experiments Future SK US-Japan Seminar - - PowerPoint PPT Presentation

US-Japan Seminar ‘ββ Decay and ν Mass’ Kapalua, Maui, September 2005 Michael Smy UC Irvine

Future SK Future SK-

• Experiments

Experiments

Solar Neutrinos Solar Neutrinos

Michael Smy, UC Irvine

SSM spectrum

pp

7Be

pep

8B

Solar MSW Solar MSW-

• Vacuum Transition

Vacuum Transition

P(νe νe)

Vacuum osc. dominant matter osc. dominant Expected P(νe νe)

0.2 0.4 0.8 0.6

Courtesy of M. Nakahata, ICRR

0.2 0.4 0.8 0.6

Expected low energy upturn (8B)

SK (νe scattering) SNO CC

sin2(θ) 0.22 0.28 0.35

∆m2=8.3x10-5eV2

∆m2 (eV2) 9.1 x 10-5 8.3 x 10-5 7.4 x 10-5

∆m2=8.3x10-5eV2

sin2(θ)=0.28 sin2(θ)=0.28

Total energy

Arbitrary unit Arbitrary unit

current threshold current threshold

~20% in SNO and ~10% in SK distortion is expected from 4 MeV to 15 MeV

Courtesy of M. Nakahata, ICRR

• L/E Oscillation Analysis
• Three Flavor Oscillations
• Appearance of τ leptons

Michael Smy, UC Irvine

Atmospheric Neutrinos Atmospheric Neutrinos

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

SK II Analysis Preliminary

L/E Analysis L/E Analysis

SK I Analysis

Courtesy of K. Scholberg, Duke University

Look for Non Look for Non-

• Zero

Zero θ θ13

13 in

in Enhancement of Enhancement of ν νe

e for some Angles/Energies

for some Angles/Energies

Normal hierarchy: resonance for neutrinos

P(νµ→ νe)

m

2

0.003eV

2 ,sin 2 23

0.5,sin

2 13

0.026

matter enhancement

P(νµ→ νe) P(νe→ νµ) P(νµ→ νµ) P(νe→ νe)

GeV

co s 0.6

Courtesy of K. Scholberg, Duke University

Positive ∆m2 Negative ∆m2 Null oscillation ∆m2= 0.002 eV2 sin2θ23 = 0.5 sin2θ13 = 0.05

SK 20 years

Single-ring electrons (2.5<P<5.0GeV)

cosθ

Courtesy of K. Scholberg, Duke University

Enhancement of Enhancement of Upgoing Upgoing Multi Multi-

• GeV

GeV Single Single Ring Electrons Ring Electrons

TOKYO

KEK JAERI

NARITA KAMIOKA

J-PARC

Courtesy of T. Kobayashi, KEK

Accelerator Accelerator Neutrinos Neutrinos

T2K: Search for T2K: Search for ν νµ

µ

ν νe

e Appearance

Appearance

CP-odd Solar

Main Main Matter Matter

        ⋅         ⋅ × =

−

] GeV [ ] cm g [ ] [eV 10 56 . 7

3 2 5

E a ρ

Matter eff.:

δ−δ, a-a for

e

ν ν µ →

δ θ θ sin sin 2 sin

13 12 2 12

⋅ ⋅ ∆ ≈ + − ≡ E L m P P P P ACP

Sensitivity Sensitivity indep

• indep. from

. from θ

θ13

13

(if no BG & no (if no BG & no syst

• syst. err)

# of signal ∝ sin2θ13 (Stat err∝sinθ13), CP-odd term ∝ sinθ13

. err)

Courtesy of T. Kobayashi, KEK

Kamioka J-PARC (Tokai-mura)

T2K T2K

• (0.75MW)4MW 50GeV PS @ J-PARC
• Off-axis (OA) 2~30: Eνpeak=0.5~0.8GeV
• L=295km

Courtesy of T. Kobayashi, KEK

Off Off-

• Axis: High Intensity Narrow Band Beam

Axis: High Intensity Narrow Band Beam

(ref.: BNL-E889 Proposal)

θ

Target HornsDecay Pipe

Decay Kinematics

1/γπ~θ Eπ(GeV) Eν(GeV) 5 1

OAB2.0deg OAB2.5deg OAB3.0deg

Increase statistics @ osc. max. Decrease background from HE tail

Courtesy of T. Kobayashi, KEK

Far Det. νµ flux

Sensitivity for Sensitivity for θ θ13

13

sin22θ13~0.006 (90%) 0.5xsin22θ13 sin22θ13~0.018 (3σ) sin sin2

22

2θ θ13

13 < 10

< 10-

• 3

3 can be searched if

can be searched if syst syst err ~ few % err ~ few %

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

SK with GdCl3

“ “Super Super-

• KamLAND

KamLAND” ” could collect

could collect this much data in two weeks this much data in two weeks

νe

Neutron Detection in SK: 0.1% GdCl Neutron Detection in SK: 0.1% GdCl3

3

5 10 15 20 25 30 35 40 Measured Ee [MeV] 10-2 10-1 100 101 102 103 dN/dEe [(22.5 kton) yr MeV]

• 1

Reactors Supernovae (µ) (e) Atmospheric

Antineutrino Spectrum

Michael Smy, UC Irvine

Gd γ’s with

ΣE=8MeV

From Beacom/Vagins PRL 93 171101,2004

Choubey and Petcov consider the reactor signal of SK-Gd

Courtesy of M. Vagins, UCI

Michael Smy, UC Irvine

MeV MeV Percentage for each Percentage for each γ γ line line

Gd Gd MC: Input Spectrum MC: Input Spectrum

Event Reconstruction Event Reconstruction

keep reconstr. Gd n capture reconstr. e+ vertex

distance in cm

Gd νe MC (3 MeV e+) true e+ vertex reconstr. e+ vertex

distance in cm

true Gd vertex reconstr. Gd vertex

distance in cm

Michael Smy, UC Irvine

Shape of Shape of Gd Gd Events Events

• “Patlik” variable to remove residual βγ

spallation events from solar ν sample

• Disadvantage: needs direction from

low energy direction fit, which assumes a single e-like Cherenkov Ring

Gd events e+ events Gd events e+ events

• Reconstructed Cherenkov Angle
• Disadvantage: already used as a

“guideline” for the vertex reconstruction (of only e+) i.e. distribution uses prior knowledge

Michael Smy, UC Irvine

Shape of Shape of Gd Gd Events Events

• “Patlik” variable to remove residual βγ

spallation events from solar ν sample

• Disadvantage: needs direction from

low energy direction fit, which assumes a single e-like Cherenkov Ring

Gd events e+ events Gd events e+ events

• Reconstructed Cherenkov Angle
• Disadvantage: already used as a

“guideline” for the vertex reconstruction (of only e+) i.e. distribution uses prior knowledge

Gd events e+ events

Michael Smy, UC Irvine

New Super New Super-

• K

K-

• Water Purification System

Water Purification System

No Gd No U/Th

SK Tank

Gd

0.1% Gd

0.1% Gd

remove 99.9% of Gd remove 80% of U in single pass

Final Polish RO Pretreatment (Gd Trapping Components) (Gd Passing Components)

Courtesy of M. Vagins, UCI

October 2005: Test using K2K October 2005: Test using K2K’ ’s Near Detector s Near Detector

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

y of M. Va Courtes gins, UCI

Correlated Correlated (Background (Background-

• )

) Events in SK Events in SK-

• I

I

Michael Smy, UC Irvine

all after timing cut all after prompt E cut all all after prompt E cut after prompt E, vertex cut after vertex cut after vertex cut after ∆t cut after delayed E cut

All cuts All 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 νe appearance with intense beam
• Plan to add neutron detection to SK-III for

reactor ν’s, SN relic ν’s

Michael Smy, UC Irvine