talk - International Workshop on Double Beta Decay and Neutrino
talk - International Workshop on Double Beta Decay and Neutrino
talk - International Workshop on Double Beta Decay and Neutrino
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Latest results from Borexino<br />
DBD11 <str<strong>on</strong>g>Workshop</str<strong>on</strong>g><br />
Osaka, Japan<br />
14-17 November, 2011<br />
Andrea Pocar<br />
University of Massachusetts, Amherst<br />
(<strong>on</strong> behalf of the Borexino Collaborati<strong>on</strong>)<br />
Indiana University Cyclotr<strong>on</strong> Facility - March 4, 2011<br />
Andrea Pocar - DBD11 - November 15, 2011 1
outline<br />
• solar neutrinos<br />
• Borexino<br />
• calibrati<strong>on</strong> campaign<br />
• recent results<br />
• outlook<br />
the full Borexino detector full, May 15 2007<br />
Andrea Pocar - DBD11 - November 15, 2011 2
Solar Fusi<strong>on</strong> Reacti<strong>on</strong>s<br />
p-p Solar Fusi<strong>on</strong> Chain<br />
CNO Solar Fusi<strong>on</strong> Cycle<br />
p + p → 2 H + e + + ν e<br />
p + e − + p → 2 H + ν e<br />
12<br />
C + p → 13 N + γ<br />
2H + p → 3 He + γ<br />
13<br />
N → 13 C + e + + ν e<br />
3He + 3 He → 4 He + 2 p<br />
3He + p → 4 He + e + + ν e<br />
13<br />
C + p → 14 N + γ<br />
14<br />
N + p → 15 O + γ<br />
3He + 4 He → 7 Be + γ<br />
15<br />
O → 15 N + e + + ν e<br />
7Be + e − → 7 Li + γ + ν e<br />
7Be + p → 8 B + γ<br />
15<br />
N + p → 12 C + 4 He<br />
7Li + p → α + α<br />
8B → 2 α + e + + ν e<br />
4p → He 4 +2e + +2ν e + 26.7MeV<br />
Andrea Pocar - DBD11 - November 15, 2011<br />
Image: bbc.co.uk
solar neutrino spectrum<br />
Flux (cm -2 sec -1 MeV -1 )<br />
13<br />
N<br />
15<br />
O<br />
pp<br />
BOREXINO<br />
7<br />
Be<br />
(Bahcall-Pena-Garay-Serenelli 2008)<br />
• Precise measurement < 5%<br />
uncertainties (10% in previous)<br />
• Day/Night asymmetry<br />
pep<br />
CNO<br />
17<br />
F<br />
8<br />
B<br />
7<br />
Be<br />
hep<br />
<strong>Neutrino</strong> energy (MeV)<br />
BPS08: (Bahcall) Pena‐Garay, C., & Serenelli, A. 2008, arXiv:0811.2424<br />
Lower preferred heavy metal c<strong>on</strong>tent (metallicity) decreased 7 Be by ~10%.<br />
See also A. Serenelli, S. Basu, J. Fergus<strong>on</strong>, M. Asplund, arXiv:0909.26668v2<br />
Andrea Pocar - DBD11 - November 15, 2011
neutrino oscillati<strong>on</strong>s<br />
solar, atmospheric, reactor, beam<br />
neutrinos give a nice picture of the<br />
oscillati<strong>on</strong> of three active flavors<br />
δm 2 12 ∼ 7.6 × 10 −5 eV 2<br />
sin 2 θ 12 ∼ 0.3<br />
δm 2 23 ∼ 2.4 × 10 −3 eV 2<br />
sin 2 θ 23 ∼ 0.4<br />
sin 2 θ 13 ∼ small<br />
neutrino oscillati<strong>on</strong>s are now a firmly<br />
established experimental fact<br />
the MSW-LMA soluti<strong>on</strong> for solar<br />
neutrinos predicts an energy-dependent<br />
survival probability for electr<strong>on</strong> neutrinos<br />
P ee<br />
1.0<br />
0.8<br />
0.6<br />
0.4<br />
0.2<br />
Bahcall &<br />
Peña-Garay<br />
Andrea Pocar - DBD11 - November 15, 2011 5<br />
0.0<br />
β≈cos(2θ 12<br />
)<br />
E
Borexino science<br />
Vacuum<br />
oscillati<strong>on</strong>s<br />
Matter<br />
enhancement<br />
Physics of neutrino oscillati<strong>on</strong><br />
Precisi<strong>on</strong> measurements of solar neutrino<br />
fluxes can help map out the transiti<strong>on</strong><br />
regi<strong>on</strong>, sensitive to new physics.<br />
Solar physics<br />
A spectroscopic measurement of the<br />
different solar neutrino rates can verify<br />
the St<strong>and</strong>ard Solar Model predicti<strong>on</strong>s,<br />
rule out accreti<strong>on</strong> scenarios <strong>and</strong> help<br />
determine the core C+N abundance.<br />
Andrea Pocar - DBD11 - November 15, 2011 6
Gran Sasso<br />
Perugia<br />
Heidelberg<br />
Hamburg<br />
Budapest<br />
Milano<br />
Genova<br />
München<br />
Kraków<br />
Kurchatov<br />
Moscow<br />
the Borexino Collaborati<strong>on</strong><br />
JINR Dubna<br />
Princet<strong>on</strong><br />
Virginia Tech<br />
UMass<br />
Amherst<br />
Paris<br />
St. Petersburg<br />
Andrea Pocar - DBD11 - November 15, 2011 7
Borexino<br />
(<strong>on</strong>line since May 16, 2007)<br />
Real time measurement of 7 Be ν flux<br />
• Detecti<strong>on</strong> reacti<strong>on</strong>: elastic scattering<br />
ν + e - → ν + e - in liquid scintillator<br />
Cross secti<strong>on</strong> for νe is ~5 times larger than νμ,τ<br />
• 7 Be ν rate in 100t fiducial mass: 74/d (SSM), 48/d MSW-LMA c<strong>on</strong>versi<strong>on</strong> νe → νμ,τ<br />
• No directi<strong>on</strong>ality, but vertex rec<strong>on</strong>structi<strong>on</strong> from phot<strong>on</strong> arrival time<br />
• Real time enables observati<strong>on</strong> of possible periodic variati<strong>on</strong>s (seas<strong>on</strong>al, day-night)<br />
Energy spectroscopy (resoluti<strong>on</strong>: ~ 5% @ 1 MeV)<br />
• Software threshold set by 14 C at 200 keV (hardware threshold: ~60 keV)<br />
• <strong>Neutrino</strong> signature: shape of the energy spectrum<br />
Key point: suppressi<strong>on</strong> of background sources<br />
Andrea Pocar - DBD11 - November 15, 2011<br />
8
Borexino<br />
L’AQUILA<br />
Tunnel of 10.4 km<br />
Scintillator:<br />
270 t PC+PPO (1.5g/l)<br />
in a 150µm thick<br />
Inner nyl<strong>on</strong> vessel (R=4.25m)<br />
Buffer regi<strong>on</strong>:<br />
PC+DMP quencher (5g/l)<br />
4.25m
ackground reducti<strong>on</strong>: graded shielding design<br />
internal radioactivity<br />
traces of radioisotopes in the<br />
scintillator (U,Th, 40 K)<br />
Rn<br />
external γ rays<br />
from fluid buffer, steel sphere,<br />
PMT glass <strong>and</strong> light<br />
c<strong>on</strong>centrators ( 40 K, 208 Tl, 214 Bi)<br />
rad<strong>on</strong> emanati<strong>on</strong><br />
from the PMTs <strong>and</strong> steel<br />
sphere<br />
cosmic mu<strong>on</strong>s<br />
<strong>and</strong> their sec<strong>on</strong>daries<br />
cosmogenics<br />
neutr<strong>on</strong>s <strong>and</strong> radi<strong>on</strong>uclides<br />
from µ spallati<strong>on</strong> <strong>and</strong> hadr<strong>on</strong>ic<br />
showers<br />
fast neutr<strong>on</strong>s<br />
from external mu<strong>on</strong>s<br />
Andrea Pocar - DBD11 - November 15, 2011 10
measurement of the 7 Be solar neutrino flux<br />
192 live days of data - Phys. Rev. Lett. 101, 091302 (2008)<br />
210 Po<br />
α’s<br />
7 Be ν’s<br />
11 C<br />
85 Kr<br />
210 Bi + CNO ν’s<br />
Rate( 7 Be) = 47 ± 3(stat) ± 4(sys) cpd/100 t<strong>on</strong>s<br />
Φ( 7 Be) = (5.18 ± 0.51) × 10 9 cm −2 s −1<br />
Rate( osc) / = 74 ± 4 cpd/100 t<strong>on</strong>s (high Z)<br />
Andrea Pocar - DBD11 - November 15, 2011 11
calibrati<strong>on</strong> sources<br />
spiked water vial<br />
spiked<br />
scintillator<br />
vial<br />
AmBe<br />
source vial<br />
AmBe source<br />
inserti<strong>on</strong> system<br />
Andrea Pocar - DBD11 - November 15, 2011 12
detector calibrati<strong>on</strong>s<br />
4 campaigns in ʼ09<br />
35 days, 295 positi<strong>on</strong>s<br />
• positi<strong>on</strong> known with ~2 cm accuracy with 7<br />
CCD cameras mounted <strong>on</strong> the steel sphere<br />
• external γ source deployed in water tank (’10)<br />
Andrea Pocar - DBD11 - November 15, 2011 13
positi<strong>on</strong> <strong>and</strong> energy calibrati<strong>on</strong><br />
57<br />
Co<br />
139<br />
Ce<br />
203<br />
Hg<br />
85<br />
Sr 54<br />
Mn 65<br />
Zn 40<br />
K n + H 60<br />
Co<br />
Study light yield, quenching,<br />
positi<strong>on</strong> variati<strong>on</strong>.<br />
Data-‐MC mean light yields <br />
agree to 1% in F.V. <br />
Measure positi<strong>on</strong><br />
resoluti<strong>on</strong>: 10 – 12 cm<br />
Fiducial Volume:<br />
1.0 +0.005<br />
-‐0.013<br />
Z rec – Z ccd (m)<br />
R rec – R ccd (m)<br />
energy<br />
radial<br />
C<strong>on</strong>firm energy/radial<br />
PDF for external bg<br />
with high intensity<br />
Th-228 source<br />
(arXiv 1110.1217)<br />
Andrea Pocar - DBD11 - November 15, 2011
data reducti<strong>on</strong> <strong>and</strong> signal extracti<strong>on</strong><br />
14<br />
C<br />
210<br />
Po<br />
750 days of data with<br />
100t<strong>on</strong> norm.<br />
MC; signal + intrinsic BG<br />
FV cut<br />
soft α/β cut<br />
mu<strong>on</strong> <strong>and</strong> daughter<br />
11<br />
C<br />
No cut<br />
7<br />
Be+ 85 Kr<br />
ext.bkg<br />
• A spectral fit is applied including the following signal + all intrinsic<br />
background comp<strong>on</strong>ents.<br />
– 7 Be, 85 Kr, 14 C, 11 C<br />
– 210 Bi (very similar to CNO in this limited energy regi<strong>on</strong>)<br />
– pp, pep, 8 B, <strong>and</strong> CNO neutrinos fixed at SSM-LMA value<br />
• Fit with <strong>and</strong> without statistical subtracti<strong>on</strong> of 210 Po events, based <strong>on</strong> α/β<br />
pulse shape discriminati<strong>on</strong>.<br />
• Two independent methods (MC based <strong>and</strong> analytical) were applied.<br />
Andrea Pocar - DBD11 - November 15, 2011<br />
15
7 Be solar neutrino flux in Borexino<br />
First measurement: 192 days [PRL 101 091302 (2008)]<br />
Rate 7Be = 49 ± 3(stat) ± 4 (sys) events/day/100 t<strong>on</strong><br />
New results [PRL 107 141302 (2011)]<br />
Rate 7Be = 46 ± 1.5 (stat) +1.5 -1.6 (sys) events/ day / 100 t<strong>on</strong><br />
➡ Increased statistics (about x4 times)<br />
➡ Lower systematic errors (calibrati<strong>on</strong> campaign)<br />
➡
spectral fits<br />
• Different fits:<br />
- with <strong>and</strong> without alpha subtracti<strong>on</strong><br />
- M<strong>on</strong>te Carlo vs analytical<br />
- energy scale <strong>and</strong> resoluti<strong>on</strong><br />
• removed mu<strong>on</strong>s, Rad<strong>on</strong> delayed coincidences<br />
• 210 Bi, 85 Kr, 11 C are free parameters<br />
• pp, pep, CNO rates fixed<br />
7<br />
Be ν 46.0 ± 1.5 (stat) +1.5 -1.6 (sys)<br />
85<br />
Kr 31.2 ± 1.7 (stat) ± 4.7 (sys)<br />
210<br />
Bi 41.0 ± 1.5 (stat) ± 2.3 (sys)<br />
11<br />
C 28.5 ± 0.2 (stat) ± 0.7 (sys)<br />
Andrea Pocar - DBD11 - November 15, 2011 17
Borexino systematics<br />
First measurement: 192 days<br />
[PRL 101 (2008) 091302]<br />
Source Uncertainty (%)<br />
Total scintillator mass 0.2<br />
Fiducial mass ratio 6.0<br />
Live Time 0.1<br />
Detector resp<strong>on</strong>se functi<strong>on</strong> 6.0<br />
Cuts efficiency 0.3<br />
Total Systematic Error 8.5<br />
New results<br />
[PRL 107 141302 (2011)]<br />
Source Uncertainty (%)<br />
Scintillator density 0.05<br />
Fiducial volume +0.5 -1.3<br />
Live Time 0.04<br />
Optical resp<strong>on</strong>se 2.7<br />
Cuts efficiency 0.1<br />
Fit methods 2.0<br />
Trigger efficiency, stability
Implicati<strong>on</strong> <strong>on</strong> solar physics<br />
• Metallicity c<strong>on</strong>troversy<br />
Fit to the available all solar<br />
neutrino data leaving free f Be<br />
<strong>and</strong> f B<br />
( f = Φ/Φ(SSM) )<br />
Hard to discriminate<br />
• Other solar neutrino sources<br />
Each solar neutrino flux can be calculated<br />
with solar luminosity c<strong>on</strong>straint.<br />
+0.02<br />
M.C.G<strong>on</strong>zalez-Garcia, M.Mart<strong>on</strong>i, J.Salvado<br />
JHEP 05(2010)072 / 0910.4584<br />
Φ pp = (6.06 - 0.06 )x10 10 cm -2 s -1 (f pp = 1.013)<br />
Φ CNO < 1.3x10 9 cm -2 s -1 (f CNO < 2.5) at 95%C.L.<br />
Andrea Pocar - DBD11 - November 15, 2011<br />
19
Pee survival probability (862 keV)<br />
P ee =0.51 ± 0.07<br />
Experimental<br />
uncertainty<br />
Experimental+SSM<br />
uncertainty<br />
MSW-LMA with 1σ range<br />
of mixing parameters<br />
un-oscillated 862 keV νe flux: (2.78 ± 0.13) x 10 9 cm −2 s −1 [(3.10 ± 0.15) x 10 9 cm −2 s −1 total]<br />
with the MSW-LMA soluti<strong>on</strong>, the absolute 7 Be νe flux is: (4.84 ± 0.24) x 10 9 cm −2 s −1<br />
Ratio of the Borexino measurement to the SSM predicti<strong>on</strong> is fBe = 0.97 ± 0.09<br />
Andrea Pocar - DBD11 - November 15, 2011 20
no day/night effect<br />
matter effects of neutrinos crossing the<br />
earth could enhance the night rate by<br />
regenerati<strong>on</strong> of electr<strong>on</strong> neutrinos<br />
depends <strong>on</strong>:<br />
oscillati<strong>on</strong> parameters <strong>and</strong> neutrino energy<br />
Source<br />
Adn error<br />
Live-time < 5 x 10 -4<br />
7<br />
Be = 0.04 ± 0.57 events/day/100t<br />
210<br />
Po = -21.8 ± 0.9 events/day/100t<br />
7<br />
Be spectrum (arbitrary units)<br />
Night - Day spectrum<br />
Cut efficiency 0.001<br />
210<br />
Bi time variati<strong>on</strong> ± 0.005<br />
Fit procedure ± 0.005<br />
Sys error 0.007<br />
A dn =0.001 ± 0.012 (stat) ± 0.007 (syst)<br />
Andrea Pocar - DBD11 - November 15, 2011 21
effect <strong>on</strong> neutrino oscillati<strong>on</strong>s<br />
MSW<br />
Adn<br />
LMA ~ 0%<br />
LOW 23 ± 11%<br />
Best fit:<br />
Δm 2 = 5.3x10 -5 eV 2<br />
tan 2 θ=0.46<br />
Excluded by<br />
Day/Night<br />
99.73% CL<br />
Without Borexino<br />
LMA<br />
LOW<br />
With Borexino<br />
( 7 Be flux <strong>and</strong> day/night)<br />
LMA<br />
LOW is excluded<br />
at > 8.5 σ<br />
Andrea Pocar - DBD11 - November 15, 2011 22
8 B solar neutrinos at low threshold<br />
R( 8 B)=0.22 ± 0.04 (stat) ± 0.01 (syst) cpd/100 t<br />
First measurement of Pee in vacuum ( 7 Be ν)<br />
<strong>and</strong> matter-enhanced regime ( 8 B ν) in the<br />
same detector<br />
P ee =0.29 ± 0.10<br />
Agreement<br />
with LMA<br />
High Z<br />
Low Z<br />
Phys Rev D 82, 0330006 (2010)<br />
Andrea Pocar - DBD11 - November 15, 2011 23
1. Scientifically desirable<br />
pep <strong>and</strong> CNO solar neutrinos ?<br />
+ pep rate is closely c<strong>on</strong>nected with pp<br />
rate (low energy, mostly obscured by<br />
14 C), first fusi<strong>on</strong> step in the sun<br />
+ CNO flux has large theoretical<br />
uncertainty (30%) depending <strong>on</strong><br />
unknown factors of the solar chemical<br />
compositi<strong>on</strong> (metallicity of the mantle)<br />
2. Hard to detect<br />
+ the expected pep <strong>and</strong> CNO solar<br />
neutrino rates are 5-10 times smaller than<br />
7 Be, which obscures most of their<br />
spectrum<br />
+ 210 Bi, 40 K <strong>and</strong> 208 Tl ( 232 Th) backgrounds<br />
Counts/(10 keV x day x 100 t<strong>on</strong>s)<br />
5<br />
10<br />
4<br />
10<br />
3<br />
10<br />
2<br />
10<br />
10<br />
1<br />
-1<br />
10<br />
-2<br />
10<br />
-3<br />
10<br />
Tuesday, May 27, 2008<br />
New Results:192 Days<br />
200 400 600 800 1000 1200 1400 1600 1800 2000<br />
Energy [keV]<br />
3. 11 C subtracti<strong>on</strong><br />
Fit: ! 2 /NDF = 185/174<br />
7<br />
Be: 49±3 cpd/100 t<strong>on</strong>s<br />
210<br />
Bi+CNO: 23±2 cpd/100 t<strong>on</strong>s<br />
85<br />
Kr: 25±3 cpd/100 t<strong>on</strong>s<br />
11<br />
C: 25±1 cpd/100 t<strong>on</strong>s<br />
14<br />
C<br />
10<br />
C<br />
CNO, pep<br />
+ when a mu<strong>on</strong> produces a 11 C, simulati<strong>on</strong>s<br />
suggest that a free neutr<strong>on</strong> is also emitted<br />
~95% of the times, allowing for event-byevent<br />
subtracti<strong>on</strong><br />
+ investigating statistical subtracti<strong>on</strong><br />
Andrea Pocar - DBD11 - November 15, 2011 24<br />
25
pep <strong>and</strong> CNO neutrinos<br />
The 125 mu<strong>on</strong>-‐neutr<strong>on</strong> coincidences/day can be vetoed without <br />
excessive loss of live
pep <strong>and</strong> CNO neutrinos<br />
210<br />
Po<br />
7<br />
Be v<br />
85<br />
Kr<br />
11<br />
C<br />
• Cosmogenic, t 1/2 <br />
= 29 min<br />
• Borexino mu<strong>on</strong> rate = 4200/day<br />
Can’t veto aAer every mu<strong>on</strong>! <br />
210<br />
Bi<br />
External <br />
Background<br />
pep v<br />
CNO v<br />
The 125 mu<strong>on</strong>-‐neutr<strong>on</strong> coincidences/day can be vetoed without <br />
excessive loss of live
μ Track<br />
three-fold<br />
coincidence<br />
Andrea Pocar - DBD11 - November 15, 2011
μ Track<br />
three-fold<br />
coincidence<br />
11<br />
C<br />
µ + 12 C → µ + 11 C + n<br />
Andrea Pocar - DBD11 - November 15, 2011
μ Track<br />
three-fold<br />
coincidence<br />
n Capture<br />
11<br />
C<br />
µ + 12 C → µ + 11 C + n<br />
∆t ∼ 250 µs:<br />
n + p → d ∗ → d + γ (2.2 MeV)<br />
Andrea Pocar - DBD11 - November 15, 2011
μ Track<br />
three-fold<br />
coincidence<br />
n Capture<br />
11<br />
C<br />
µ + 12 C → µ + 11 C + n<br />
∆t ∼ 250 µs:<br />
n + p → d ∗ → d + γ (2.2 MeV)<br />
∆t ∼ 30 min:<br />
11 C → 11 B + e + + ν (+ 0.96 MeV)<br />
Andrea Pocar - DBD11 - November 15, 2011
3-fold coincidence results (not <strong>on</strong>ly)<br />
remove 91% of background<br />
sacrificing 51.5% of live time<br />
Andrea Pocar - DBD11 - November 15, 2011 27
3-fold coincidence results (not <strong>on</strong>ly)<br />
remove 91% of background<br />
sacrificing 51.5% of live time<br />
50% of β + decays produce<br />
ortho-positr<strong>on</strong>ium (t1/2=3 ns):<br />
- time shift<br />
- multi-site (gammas)<br />
- i<strong>on</strong>izati<strong>on</strong> density profile<br />
Andrea Pocar - DBD11 - November 15, 2011 27
electr<strong>on</strong>/positr<strong>on</strong> pulse shape discriminati<strong>on</strong><br />
use boosted decisi<strong>on</strong> tree (BDT)<br />
to optimize discriminati<strong>on</strong><br />
- train, test, build PDF with events<br />
selected by TFC<br />
- include BDT variable in signal<br />
extracti<strong>on</strong><br />
- binned likelihood fits in energy, radius<br />
<strong>and</strong> BDT<br />
- 2D energy/radius <strong>and</strong> energy/BDT pdf’s<br />
- simultaneous fits to TCF-accepted <strong>and</strong><br />
rejected events (double bg statistics)<br />
Andrea Pocar - DBD11 - November 15, 2011 28
pep <strong>and</strong> CNO results<br />
Best fit (‘+’): (0, 3.13)<br />
+<br />
*<br />
SSM + LMA predicW<strong>on</strong> (‘*’): (5.3, 2.8)<br />
Andrea Pocar - DBD11 - November 15, 2011 29
pep <strong>and</strong> CNO results<br />
Borexino pep counWng rate: 3.1 ± 0.6 stat <br />
± 0.3 sys <br />
/(d 100T)<br />
P ee<br />
(1.44 MeV) = 0.62 ± 0.17 <br />
Φ pep<br />
= 0 disfavoured at 98% C.L.<br />
Borexino CNO counWng rate: < 7.9 (
outlook<br />
Scintillator purificati<strong>on</strong><br />
Operati<strong>on</strong>s to further purify the scintillator <strong>on</strong>going since July 2010<br />
- no sign of 85 Kr since January 2011<br />
- moderate reducti<strong>on</strong> in 210 Bi<br />
- operati<strong>on</strong>s c<strong>on</strong>tinue targeting 210 Bi (<strong>and</strong> maybe 210 Po)<br />
Physics<br />
Borexino will operate for 3 or more years<br />
- neutrino “snapshot” of entire solar neutrino spectrum<br />
- CNO, pp?<br />
- better statistics for 8 B, pep, geo-neutrinos<br />
- supernovae neutrinos<br />
- exotica<br />
Andrea Pocar - DBD11 - November 15, 2011 31
Andrea Pocar Pocar - DBD11 - SiLAFAE - November 201015, - 2011 Dec. 8, 2010<br />
32<br />
summary<br />
• Borexino has achieved its<br />
original design goal<br />
• precisi<strong>on</strong> 7Be measurements<br />
improves experimental<br />
c<strong>on</strong>straint at low energy<br />
• day/night improves solar <strong>on</strong>ly<br />
c<strong>on</strong>straint <strong>on</strong> mixing<br />
parameters<br />
• first evidence of pep flux<br />
• attempt at measuring CNO,<br />
pep fluxes<br />
• supernovae, geo-neutrinos,<br />
superluminal neutrinos, other<br />
exotic physics
Andrea Pocar Pocar - DBD11 - SiLAFAE - November 201015, - 2011 Dec. 8, 2010<br />
32<br />
summary<br />
• Borexino has achieved its<br />
original design goal<br />
• precisi<strong>on</strong> 7Be measurements<br />
improves experimental<br />
c<strong>on</strong>straint at low energy<br />
• day/night improves solar <strong>on</strong>ly<br />
c<strong>on</strong>straint <strong>on</strong> mixing<br />
parameters<br />
• first evidence of pep flux<br />
• attempt at measuring CNO,<br />
pep fluxes<br />
• supernovae, geo-neutrinos,<br />
superluminal neutrinos, other<br />
exotic physics<br />
thank you!