future solar neutrino projects
DESCRIPTION
Neutrino Champagne, Oct.19, 2009. M.Nakahata. Kamioka observatory, ICRR, Univ. of Tokyo. Future solar neutrino projects. Value for neutrino oscillations Value for astrophysics Current status of future solar neutrino projects Conclusions. - PowerPoint PPT PresentationTRANSCRIPT
Future solar neutrino projects
Value for neutrino oscillations Value for astrophysics Current status of future solar neutrino projects Conclusions
Neutrino Champagne, Oct.19, 2009
M.NakahataKamioka observatory, ICRR, Univ. of Tokyo
Thanks to M.Chen, D.McKinsey, G.Ranucci, R.Raghavan, G.Ranucci, T.Lasserre, K.Inoue, H.Ejiri, S.Petcov, A.Kopylov, R.E.Lanou, M.Smy, Y.Takeuchi, B.Yang, M.Ikeda, Y.Koshio for information and discussion
Solar global and KamLAND reactor
Solar global
KamLAND
Do we fully understand solar neutrino oscillation?What future solar neutrino experiments can improve (or find something new) in solar neutrino oscillation?
SNO collaboration: arXiv:0910.2984
Energy dependence of the survival probability
P(
e
e)
Vacuum osc. dominant
matter osc.
(MeV)SSM spectrumpp
7Bepep
8B
P=1 - 0.5 ・ sin22
P=sin2
13N15O
17F
Current status of 8B spectrum measurement
m2=6.3x10-5eV2, tan2=0.55m2=7.2x10-5eV2, tan2=0.38
systematic errorSK-I
SNO CC (LETA)
4.5 9.5Ekin(MeV)
unoscillated MC
Oscillated MC
246 days100tons
Borexino
Dat
a/S
SM
2=21.52/15d.o.f. for flat = 22.56/15d.o.f. for LMA
Nonstandard models to predict flat spectrum
Holanda and Smirnov, Phys.Rev.D69(2004)113002.(hep-ph/0307266)
Barger, Huber and Marfatia, Phys.Rev.Lett.95:211802,2005(hep-ph/0502196)
Miranda, Tortola and Valle, JHEP 0610:008,2006.(hep-ph/0406280)
Friedland, Lunardini, Pena-GarayPLB594(2004)347(hep-ph/0402266)
Gonzalez-Garcia,Holanda,Zukanovich ,Funchal, JCAP 0806:019,2008. (hep-ph/0803.1180)
Sterile neutrino
Non standard Interaction
MaVaN
Unparticle
8B day/night asymmetry
Summary of ADN(D-N) / 0.5(D+N)
ES CC
Solar global(95%CL)
Solar+KamLAND
This is for Electron Scattering (ES). Expected Day/Night of CC is about 1.5 x ES
Day/night asymmetry is 1~5% level for the solar global solution.
~1.5% for the solar+KamLAND solution.
Current statusExpected D/N asymmetry
Sensitivity of Megaton Water Cherenkov detector8B spectrum distortion
Hep neutrino measurementEe (MeV)
Dat
a/SS
M
5 Mton·years
Correlated sys. error of SK
(energy scale error : 0.64%)
5 Mton·years
Integral spectrum
1/2 of SK
Day/Night Asymmetry
ADN= -1.5% ±0.3%(stat.) ± ??(sys.) with 5 Mton·years (sin2=0.31, m2 =7.6×10-5 eV2)
Assuming ±0.4%(sys.), error of m2 is ±~17%(1).
sin2=0.28, m2 =8.3×10-5 eV2
Estimated based on SK signal/noise ratio
Expected energy spectrum of -e scattering
With oscillation
Event rate: (/5years/10tonXe, 8.3tonNe, 7.2ton liq. Scint.)
pp: 11646 7Be: 6257 pep: 352 CNO: 651 8B: 66 (assuming 50keV threshold, BPS08(GS), tan2=0.467, m2 =7.59×10-5 eV2)
(Above 7Be energy: pep: 158 CNO: 119 )
Sensitivity of mixing angle by pp experiments
Value of13 is needed for precise determination of 12.
10 ton (Xe) detector
e scattering experiment
5 years data
Statistical error(~1%) + SSM flux error (1%)
Current error size (68% C.L.)From the SNO LETA paper
68% CL
95% CL
68% CL
95% CL
Future: with reactor 13 experiments
1 error (assuming m
23=2.3x10-3 eV2)
Double CHOOZ value from T.Lasserre
Sensitivity of mixing angle by pp experiments
Value of future solar neutrino experiments for astrophysics
Solar neutrino spectrum from standard solar model
Spectroscopic measurement byKamiokande, Super-K, SNO, Borexino
Measured by Borexino
8B is only 0.01% of all solar neutrinos.Be is 8% of all solar neutrinos.Majority of solar neutrinos, especially pp , are not measured yet.Measurement of various neutrinos, especially CNO , is important for astrophysics.
Why do solar neutrino experiments below 1-MeV?J.N.BahcallProceedings of LOWNU 2000, 172-176, e-Print: hep-ex/0106086
C. Pena-Garay and A.M.Serenelli, arXiv:0811.2424
Difference
+1.2%
+2.8%
+4.1%
-10%
-21%
-34%
-31%
-44%
In units of 1010(pp), 109(7Be), 108(pep, 13N, 15O), 106(8B, 17F), 103 hep cm-2s-1
Two solar abundances: GS98 vs AGS05Z/X = 0.0229 0.0165 Especially, C,N,O,Ne,Mg are 30~50% reduced in AGS05
BPS08: Neutrino fluxes and uncertainties
A problem in standard solar model
AGS05:Inconsistent with helioseismology…
Surface helium mass fraction
Sound speed Density
Boundary of convection zone
R/Rsun R/Rsun
c/c
Revised Solar modelAGSS09
6.03
1.44
8.18
4.64
4.85
2.07
1.47
3.48
AGSS09vs. GS98
+1.0%
+2.1%
+3.5%
-8.5%
-18%
-28%
-32%
-40%
AGSS09
0.724
0.231
Sound speed
Density
R/Rsun
c/c
AGS05
AGSS09
GS98
AGS05
AGSS09
GS98
(Serenelli et al.,astro-ph/0909.2668 ) Released on Oct.7, 2009
AGSS09 slightly improved the disagreement.But, still it does not yet reproduce heliosismology, RCZ and YS.
What is Standard Solar model• Solve evolution from zero age along the main sequence
– Using equations of hydrostatic equilibrium, mass continuity, energy
conservation, energy transformation (either by convection or radiation), and equation of state
– Input parameters of nuclear fusion cross section (S factor) and etc.
• Boundary conditions– Current mass, radius, luminosity, age of the sun
• Assumptions– Sun was chemically homogeneous at Time=0.– Initial abundances of heavy element s (i.e. other than H and He) are
same as current surface abundance or meteorite.Are the assumptions correct?For example, Haxton proposed that metal depletion during planet formation. It might have lowered metal content in the solar photosphere, but keeping higher metal content in the core.(arXiv:0809.3342 [astro-ph] )
It is important to look at solar core using solar neutrinos.
8B – 7Be flux correlation
8B flux
7B
e flu
x
C.Pena-Garay, PHYSSUN workshop at Gran Sasso Oct.16-17, 2008
GS98 abundance
AGS05 abundance
With SNO LETA
M. Chen, SNOLAB workshop, Aug.2009
Preliminary
Measure CNO flux (to ±10%) and compare with solar models to differentiate high-Z / low-Z core metallicity
N13 flux vs. 8B (made by M.Chen et al.)
Currentexperiment reaction detector
SAGE e71Ga→e- 71Ge 50 ton gallium radiochemical (pp, 7Be)
Super-K e-→e- 32,000 ton water Cherenkov (8B)
BOREXINO e-→e- 100 ton Liquid scintillator (7Be, 8B, CNO)
KAMLAND e-→e- 1000 ton Liquid scintillator (7Be, 8B, CNO)
SNO+ e-→e- 1000 ton Liquid scintillator (pep, CNO)
XMASS e-→e- 10 ton Liquid Xe (pp, 7Be)
CLEAN e-→e- 50 ton Liquid Ne (pp, 7Be)
LENS e115In→e-
115Sn,e,10 ton In loaded scintillator
HERON e-→e- 10 ton super-fluid He (pp, 7Be)
MOON e100Mo→e-
100Tc()3.3 ton 100Mo foil + plastic scintillator
Lithium e7Li→e- 7Be Radiochemical, 10 ton lithium
Future/Proposed solar experiments
800kg detector(FV 100kg)
Dark matter
~20 ton detector(FV 10ton)pp, 7Be solar neutrinosDark matterDouble beta decay
Prototype detector (FV 3kg) R&D
~2.5m~1m~30cm
Confirmation of feasibility of the ~1ton detector
Under construction
finished
XMASS
神岡坑内
Water tank for cosmic ray veto,Shield gamma and neutrons 20m
15m
XMASS 800kg detector
Hall C at Kamioka
800 kg liquid XeViewed by 640 2-inch PMTs
10mx10mh water tankDistillation tower(remove Kr with 6kgXe/hour)
700L liquid Xe reservoir
Gas Xe reservoir
Hall C at Kamioka
Hmamatsu/XMASS product
Low background PMT U : ~1.4mBq/PMT Th : ~1.9mBq/PMTMass production of all PMTs was finished.
PMT support structure under construction. (ready by middle of November)
Preparation for XMASS 800kg detector
Construction by the end of 2009.Data taking will start early next year.
CLEAN
Schedule:
2010-2012: engineering of CLEAN2012-2015: Detector construction2015-2019: Liquid argon operation2020-2024: Liquid neon operation
Science:WIMP dark matterpp solar neutrinosSupernova neutrinos (coherent)
R&D progress:
Charcoal work well to remove impurities in neon
Neon light yield is ~30,000 ptohons/MeV (comparable to other noble liquids. ~6 p.e./keV in the full size CLEAN)
Compton edge of 511 keV gamma(measured by 3.14 liter MicroCLEAN)from D.McKinsey
from D.McKinsey
SNO+
Schedule:
2009-2010: Construction of hold-down net2009-2010: Scintillator process and purification install.Early 2011: Ready for filling liquid scintillator.2011: Commissioning and data taking
Science:
Double beta decay using Ndpep and CNO solar neutrinosGeo neutrinosReactor neutrinosSupernova neutrinosSupernova neutrinos (coherent)
Information from M.Chen
SNO+ Budget approved in June 2009.
1000 ton liquid scintillator at 6000 m.w.e. underground
SNO+ pep and CNO Solar Neutrino Signals
3600 pep events/(kton·year), for electron recoils >0.8 MeV
CNO extracted with±6% uncertainty (assuming target background levels 210Bi and 210Po, U, Th, 40K achieved) in three years
from M.Chenpep neutrino measurement uncertainty ~ 4.5%
Cylindrical cut Around muon-track
Spherical cut around 2.2 gamma to reject 11C event
Neutron production
Muon track
+12C-->11C+n+
11B+e++e
n capture (2.2 MeV)
Borexino Coll.:Phys.Rev.C74,045805(2006)
Best estimate for cosmogenic 11C is 25 cpd/100 tons (1.1 m-2h-1, <E>325 GeV) CNO:≈ 5 cpd/100 tons pep:≈ 2 cpd/100 tons Expected from SSM with oscil.
Borexino for CNO and pep
Necessity of both ES and CC experiments
Charged Current(CC) experiment: e flux measuremente scattering(ES) experiment: e + flux measurement
=0.30 for pp neutrino=0.21 for 7Be neutrino
SSM prediction
e
e
CC exp.
e
ES exp.
Total flux (exp.)
e
compare
Both of ES and CC experiments are necessary, if we want to measure total flux without relying on oscillation parameters obtained by other experiments.
From Raghavan
LENS Signal [SSM(low CNO) + LMAxDetection Efficiency
pp: =64%;7Be ^others: >85% Rate: pp 40 /y /t In 2000 pp ev. / 5y ±2.5% Design Goal: S/N ≥ 3
Access to pp spectral Shape for the first time
Signal electron energy (= Eν – Q) (MeV)
Coincidence delay time μs
Tag Delayed coincidenceTime Spectrum
Signal area
BgdS/N = 1
S/N = 3
Fitted Solar Nu Spectrum(Signal+Bgd) /5 yr/10 t In
Indium Bgd
S/N=3pp
7Be
pepCNO
7Be*;;;
115In ( 95.7%) = 6.4x1014 y
115Sn
B(GT) = 0.17; Q=114
e1
(e/)2 115.6 (e/ = 0.96)
3 497.3
115 In(p,n)100.8 (e/ =5.7)
= 4.76 s
max = 498.8
= 16 ps
= 231s
9/2+
1/2+
3/2+
7/2+
11/2-
0
497.3
612.8
713.6
7/2+ 1857
B(GT) ~0.01; Q =1362
e
115In ( 95.7%) = 6.4x1014 y
115Sn
B(GT) = 0.17; Q=114
e1
(e/)2 115.6 (e/ = 0.96)
3 497.3
115 In(p,n)100.8 (e/ =5.7)
= 4.76 s
max = 498.8
= 16 ps
= 231s
9/2+
1/2+
3/2+
7/2+
11/2-
0
497.3
612.8
713.6
7/2+ 1857
B(GT) ~0.01; Q =1362
e
The Indium Low Energy Neutrino Tag
115In ( 95.7%) = 6.4x1014 y
115Sn
B(GT) = 0.17; Q=114
e1
(e/)2 115.6 (e/ = 0.96)
3 497.3
115 In(p,n)100.8 (e/ =5.7)
= 4.76 s
max = 498.8
= 16 ps
= 231s
9/2+
1/2+
3/2+
7/2+
11/2-
0
497.3
612.8
713.6
7/2+ 1857
B(GT) ~0.01; Q =1362
e
115In ( 95.7%) = 6.4x1014 y
115Sn
B(GT) = 0.17; Q=114
e1
(e/)2 115.6 (e/ = 0.96)
3 497.3
115 In(p,n)100.8 (e/ =5.7)
= 4.76 s
max = 498.8
= 16 ps
= 231s
9/2+
1/2+
3/2+
7/2+
11/2-
0
497.3
612.8
713.6
7/2+ 1857
B(GT) ~0.01; Q =1362
e
The Indium Low Energy Neutrino Tag
LENS
3D Digital Localizability of Hit within one cube ~75mm precision vs. 600 mm (±2σ) by TOF in longitudinal modules x8 less vertex vol. x8 less random coinc. Big effect on Background Hit localizability independent of event energy
Test of double foilmirror in liq. @~2bar
New Detector Technology –hi event position localization
The Scintillation Lattice Chamber
Light channeling in 3-d totally Internally reflecting cubic Lattice GEANT4 sim. of concept.
Demonstration Acrylic Model
From R.Raghavan
MINILENSFinal Test detectorfor LENS-Under Construction in KURF
Goals for MINILENS 8kg In; 400 liter InLS-9x9x9 cellIn scintillation lattice
• Test detector technology Medium Scale InLS production Design and construction
• Test background suppression of In radiations by 10-11
Expect ~ 5 kHz In -decay singles rate; adequate to test trigger design, DAQ, and background suppression schemes
• Demonstrate In solar signal detection in the presence of high background (via “proxy”)
Direct blueprint for full scale LENS
Conclusions• We should make more efforts to improve our understanding
of solar neutrino oscillations, especially, matter effect.• So far, spectroscopic measurement was done only for 8B and
7Be neutrinos. Measurement of other solar neutrinos(especially, pp ) are important for astrophysics.
• SSM with improved metal abundance does not agree with helioseismology.
• Neutrino flux measurements of CNO, 7Be and 8B are important to investigate metal abundance in the core.
• Status and R&D of the future solar neutrino experiments were presented.