Davide Franco for the Borexino Collaboration Milano University & INFN

Slides:



Advertisements
Similar presentations
The SNO+ Experiment: Overview and Status
Advertisements

Riunione Settembre 2007 Gruppo 2 Inizio presa dati 2007: Auger, Borexino, Agile, Pamela Rivelatore on 2008: Gerda, Icarus, Opera,Warp, Glast, Antares,
1 Calor02 Pasadena (USA) March 2002Lino Miramonti - University and INFN Milano Borexino: A Real Time Liquid Scintillator Detector for Low Energy.
First real time 7 Be solar detection in Borexino Davide D’Angelo INFN Sez. Milano On behalf of the Borexino Collaboration.
Neutrino emission =0.27 MeV E=0.39,0.86 MeV =6.74 MeV ppI loss: ~2% ppII loss: 4% note: /Q= 0.27/26.73 = 1% ppIII loss: 28% Total loss: 2.3%
G. Sullivan - Princeton - Mar 2002 What Have We Learned from Super-K? –Before Super-K –SK-I ( ) Atmospheric Solar –SNO & SK-I Active solar –SK.
Search for spontaneous muon emission from lead nuclei with OPERA bricks M. Giorgini, V. Popa Bologna Group OPERA Collaboration Meeting, LNGS, 19-22/05/2003.
suekane 05 Erice School1 KamLAND F.Suekane Research Center for Neutrino Science Tohoku University Erice School
Prospects for 7 Be Solar Neutrino Detection with KamLAND Stanford University Department of Physics Kazumi Ishii.
Experimental Status of Geo-reactor Search with KamLAND Detector
Results and Future of the KamLAND Experiment
Neutrino emission =0.27 MeV E=0.39,0.86 MeV =6.74 MeV ppI loss: ~2% ppII loss: 4% note: /Q= 0.27/26.73 = 1% ppIII loss: 28% Total loss: 2.3%
Neutron background and possibility for shallow experiments Tadao Mitsui Research Center for Neutrino Science, Tohoku University December, 2005 Neutrino.
Atmospheric Neutrino Oscillations in Soudan 2
1 The Daya Bay Reactor Electron Anti-neutrino Oscillation Experiment Jianglai Liu (for the Daya Bay Collaboration) California Institute of Technology APS.
Solar Neutrinos Perspectives and Objectives Mark Chen Queen’s University and Canadian Institute for Advanced Research (CIFAR)
Solar neutrino measurement at Super Kamiokande ICHEP'04 ICRR K.Ishihara for SK collaboration Super Kamiokande detector Result from SK-I Status of SK-II.
Emanuela Meroni Univ. & INFN Milano NO-VE April 15-18, 2008 Borexino and Solar Neutrinos Emanuela Meroni Università di Milano & INFN On behalf of the Borexino.
Methods and problems in low energy neutrino experiments (solar, reactors, geo-) I G. Ranucci ISAPP 2011 International School on Astroparticle physics THE.
KamLAND : Studying Neutrinos from Reactor Atsuto Suzuki KamLAND Collaboration KEK : High Energy Accelerator Research Organization.
SNS2 Workshop August 28-29, 2003 Richard Talaga, Argonne1 Calibration of the OMNIS-LPC Supernova Neutrino Detector Outline –OMNIS Experiment and Detectors.
Yasuhiro Kishimoto for KamLAND collaboration RCNS, Tohoku Univ. September 12, 2007 TAUP 2007 in Sendai.
Present and future detectors for Geo-neutrinos: Borexino and LENA Applied Antineutrino Physics Workshop APC, Paris, Dec L. Oberauer, TU München.
LSc development for Solar und Supernova Neutrino detection 17 th Lomonosov conference, Moscow, August 2015 L. Oberauer, TUM.
G. Testera (INFN Genoa- Italy ) on behalf of the Borexino collaboration Low energy solar neutrino signals in Borexino Kurchatov Inst. (Russia) Dubna JINR.
M. Misiaszek (Institute of Physics, Jagellonian U., Krakow) on behalf of the Borexino Collaboration Results from the Borexino experiment Kurchatov Inst.
SNO and the new SNOLAB SNO: Heavy Water Phase Complete Status of SNOLAB Future experiments at SNOLAB: (Dark Matter, Double beta, Solar, geo-, supernova.
LoNu Workshop R. B. Vogelaar October 14, 2006 Extraordinary Neutrino Beam Free of Charge For NEUTRINO PHYSICS: WELL DEFINED HIGHEST FLUX (~10 11 cm -2.
1 水质契仑科夫探测器中的中子识别 张海兵 清华大学 , 南京 First Study of Neutron Tagging with a Water Cherenkov Detector.
New Results from the Salt Phase of SNO Kathryn Miknaitis Center for Experimental Nuclear Physics and Astrophysics, Univ. of Washington For the Sudbury.
Neutrino Physics with Borexino Davide Franco Milano University & INFN APC January 26, 2010 – Paris.
Data Processing for the Sudbury Neutrino Observatory Aksel Hallin Queen’s, October 2006.
Neutrinos from the sun, earth and SN’s: a brief excursion Aldo IFAE 2006 Pavia April 19 th.
VIeme rencontres du Vietnam
The Daya Bay Reactor Neutrino Experiment R. D. McKeown Caltech On Behalf of the Daya Bay Collaboration CIPANP 2009.
Muon and Neutron Backgrounds at Yangyang underground lab Muju Workshop Kwak, Jungwon Seoul National University 1.External Backgrounds 2.Muon.
Karsten Heeger Beijing, January 18, 2003 Design Considerations for a  13 Reactor Neutrino Experiment with Multiple Detectors Karsten M. Heeger Lawrence.
Progress on F  with the KLOE experiment (untagged) Federico Nguyen Università Roma TRE February 27 th 2006.
N eutrino O scillation W orkshop Conca Specchiulla, September 11 th 2006 Michael Smy UC Irvine Low Energy Challenges in SK-III.
Davide Franco – NOW C measurement and the CNO and pep fluxes in Borexino Davide Franco NOW2004 Conca Specchiulla September 2004.
Medium baseline neutrino oscillation searches Andrew Bazarko, Princeton University Les Houches, 20 June 2001 LSND: MeVdecay at rest MeVdecay in flight.
1 Muon Veto System and Expected Backgrounds at Dayabay Hongshan (Kevin) Zhang, BNL DayaBay Collaboration DNP08, Oakland.
A screening facility for next generation low-background experiments Tom Shutt Case Western Reserve University.
Recent Results from RENO NUFACT2014 August. 25 to 30, 2014, Glasgow, Scotland, U.K. Hyunkwan Seo on behalf of the RENO Collaboration Seoul National University.
Solar Neutrino Results from SNO
Results from Borexino Davide Franco CNRS-APC NOW 2012 September 9-16, 2012.
Second Workshop on large TPC for low energy rare event detection, Paris, December 21 st, 2004.
5th June 2003, NuFact03 Kengo Nakamura1 Solar neutrino results, KamLAND & prospects Solar Neutrino History Solar.
1 Work report ( ) Haoqi Lu IHEP Neutrino group
Double Chooz Experiment Status Jelena Maricic, Drexel University (for the Double Chooz Collaboration) September, 27 th, SNAC11.
30th International Cosmic Ray Conference in Merida, Mexico Michael Smy UC Irvine Low Energy Event Reconstruction and Selection in Super-Kamiokande-III.
The XXII International Conference on Neutrino Physics and Astrophysics in Santa Fe, New Mexico, June 13-19, 2006 The T2K 2KM Water Cherenkov Detector M.
IBD Detection Efficiencies and Uncertainties
On behalf of TEXONO collaboration
SoLid: Recent Results and Future Prospects
Simulation for DayaBay Detectors
Outline 1. Introduction & Overview 2. The experiment result 3. Future
M-C simulation of reactor e flux;
Neutron backgrounds in KamLAND
Solar neutrino detection in Borexino
Calibration, Simulations, and “Remaining” Issues
The Braidwood Reactor Neutrino Experiment
Solar Neutrino Problem
Search for sterile neutrinos with SOX: Monte Carlo studies of the experiment sensitivity Davide Basilico 1st year Workshop – 11/10/17 Tutors: Dott. Barbara.
Status of Neutron flux Analysis in KIMS experiment
Daya Bay Neutrino Experiment
2. Solar Neutrinos 2.1 Super-K
(On behalf of the TEXONO Collaboration) Academia Sinica, Taiwan
Intae Yu Sungkyunkwan University (SKKU), Korea KNO 2nd KNU, Nov
DUNE as the Next-Generation Solar Neutrino Experiment
Presentation transcript:

Davide Franco for the Borexino Collaboration Milano University & INFN Measurement of the solar 8B neutrino flux with 246 live days of Borexino …and observation of the MSW vacuum-matter transition! Neutrino Oscillation Workshop September 6-13, 2008 – Conca Specchiulla Davide Franco for the Borexino Collaboration Milano University & INFN

Solar 8B Neutrino Flux - A smooth transition is expected between the two different regimes: NOT YET EXPLORED! MSW-LMA theory: neutrino oscillations are dominated - by resonant matter-enhanced oscillations at higher energies (>5 MeV) - by vacuum oscillations at low energies (<2 MeV) Measured in real time by water Cherenkov experiments (Kamiokande, SuperKamiokande and SNO) Davide Franco – Università di Milano & INFN NOW 2008

8B n Flux Measured in Elastic Scattering Borexino expected rate in 100 tons of liquid scintillator in the entire energy spectrum: 0.49±0.05 c/d/100 tons Above 5 MeV: 0.14±0.01 c/d/100 tons > 5 MeV > 7 MeV > 5.5 MeV > 6 MeV *Threshold is defined at 100% trigger efficiency BS07(GS98) Water Cherenkov 8B solar neutrino flux measurements in elastic scattering MSW-LMA (arXiv:0806.2649): Dm2=7.69×10−5 eV2 tan2=0.45 Davide Franco – Università di Milano & INFN NOW 2008

The lowest threshold: 2.8 MeV Expected 8B n rate in 100 tons of liquid scintillator above 2.8 MeV: 0.26±0.03 c/d/100 tons 2.6 MeV g’s from 208Tl on PMT’s and in the buffer All volume R < 3 m (100 tons) Energy spectrum in Borexino (after m subtraction) > 5s distant from the 2.6 MeV g peak Davide Franco – Università di Milano & INFN NOW 2008

Background in the 2.8-16.3 MeV range Cosmic Muons High energy gamma’s from neutron captures 208Tl and 214Bi from radon emanation from nylon vessel Cosmogenic isotopes 214Bi and 208Tl from 238U and 232Th bulk contamination Raw Spectrum live-time: 246 days Count-rate: 30 c/d/100 ton S/B ratio < 1/100!!! Davide Franco – Università di Milano & INFN NOW 2008

Residual Cosmic Muon Flux (1.16 hr-1 m-2) Muons identified by the muon veto (>99% efficiency) in the 8B energy range m Muon energy spectrum At these energies, detected muons cross the buffer only (not the scintillator!) Reconstructed in the fiducial volume (radius < 3 m, ~100 tons) Davide Franco – Università di Milano & INFN NOW 2008

Muon and neutron cuts Muon cut: Neutron cut: All events detected by the outer detector are rejected Residual muon rate: <10-3 c/d Neutron cut: 2 ms veto after each muon detected by the outer detector, in order to reject induced neutrons (mean capture time ~250 ms) Residual neutron rate: ~10-4 c/d Count-rate: 4.8 c/d/100 ton Davide Franco – Università di Milano & INFN NOW 2008

Fiducial Volume Cut (radius < 3 m, ~100 tons) Surface contamination: 222Rn and 220Rn emanated from the nylon vessel Effective attenuation length: ~5 cm Residual contamination: ~10-4 c/d Count-rate: 2.3 c/d/100 ton Davide Franco – Università di Milano & INFN NOW 2008

Muon induced radioactive nuclides Cosmogenic candidate energy spectrum Entire mass 100 tons Event delay time after a m t = 29±2 ms t = 1.1±0.1 s Random Coincidences c2/ndf = 43.5/45 Davide Franco – Università di Milano & INFN NOW 2008

Cosmogenic cut Cosmogenic cut: Count-rate: 0.4 c/d/100 ton 5 s veto after each m crossing the buffer Rejection efficiency cut: 99.7% Residual short-lived cosmogenic rate: 3x10-3 c/d Dead-time: 23.4% Effective detector live-time: 188 days Count-rate: 0.4 c/d/100 ton Davide Franco – Università di Milano & INFN NOW 2008

10C and 214Bi removal 10C rejection: 214Bi rejection: Only 6% of the 10C spectrum falls in the 8B energy range Three-fold coincidence with the muon parent and the following neutron emission Efficiency 95% (MC) Invisible channel, 12C(p,t)10C, contribution estimated (MC) in 2x10-3 c/d Overall residual rate: 4x10-3 c/d 214Bi rejection: 214Bi-Po delayed coincidence (234 ms) Rejection efficiency: 89% Residual 214Bi rate: 2x10-3 c/d 10C spectrum Count-rate: 0.3 c/d/100 ton Davide Franco – Università di Milano & INFN NOW 2008

208Tl subtraction 208Tl: from 232Th contamination in the scintillator can not be tagged event by event estimated with the branching competitor 212Bi-Po 232Th contamination, assuming secular equilibrium: (6.8±1.5)x10-18 g/g Davide Franco – Università di Milano & INFN NOW 2008

The 8B n spectrum BS07(GS98) + MSW-LMA Neutrino oscillation is confirmed at 4.2 s, including the theoretical uncertainty (10%) on the 8B flux from the Standard Solar Model Davide Franco – Università di Milano & INFN NOW 2008

Summary of the Cuts and Systematic Counts 2.8-16.3 MeV 5.0-16.3 MeV None 20449 14304 Muon cut 3363 1135 Neutron cut 3280 1114 FV cut 567 372 Cosmogenic cut 71 26 10C removal 65 214Bi removal 62 Expected 208Tl 14 + 3 Measured 8B-n 48 + 8 26 + 5 BS07(GS98) 8B-n 50 + 5 25 + 3 BS07(AGS05) 8B-n 40 + 4 20 + 2 Systematic errors: 6% from the determination of the fiducial mass 3% (2%) uncertainty in the 8B rate above 2.8 MeV (5.0 MeV) from the determination of the light yield (1%) *MSW-LMA: Dm2=7.69×10−5 eV2, tan2=0.45 Davide Franco – Università di Milano & INFN NOW 2008

8B equivalent n flux Equivalent unoscillated 8B neutrino flux, as derived from the electron scattering rate 2.8-16.3 MeV 5.0-16.3 MeV Rate [c/d/100 tons] 0.26±0.04±0.02 0.14±0.03± 0.01 FESexp [106 cm−2s−1] 2.65±0.44±0.18 2.75±0.54±0.17 FESexp/FESth 0.96±0.19 1.02±0.23 > 5 MeV > 7 MeV > 5.5 MeV > 6 MeV > 2.8 MeV *Threshold is defined at 100% trigger efficiency Good agreement with the SK-I and SNO D20 measurements (same threshold at 5 MeV) Davide Franco – Università di Milano & INFN NOW 2008

Electron Neutrino Survival Probability R: measured rate En and Te: neutrino and recoiled electron energies T0 = 2.8 MeV: energy threshold E0 = 3.0 MeV: minimum neutrino energy at T0 Ne: number of target electrons sx (x=e,m-t): elastic cross sections Pee is defined such that: Pee(8B) = 0.35±0.10 (8.6 MeV) Pee(7Be) = 0.56±0.10 (0.862 MeV) For the first time, we confirm at 1.8 s, using data from a single detector, the presence of a transition between the low energy vacuum-driven and the high-energy matter-enhanced solar neutrino oscillations, in agreement with the prediction of the MSW-LMA solution for solar neutrinos Davide Franco – Università di Milano & INFN NOW 2008

Conclusion Future: 278 tons analysis Borexino has detected, for the first time, 8B solar neutrinos in liquid scintillator The Borexino energy threshold (2.8 MeV) is the lowest so far among spectral measurements of 8B neutrinos Neutrino oscillation is confirmed at 4.2 s For the first time, a single detector observed both the vacuum and matter-enhanced dominated oscillation regimes, confirming the transition at 1.8 s Future: 278 tons analysis Feasibility of a new analysis on the entire active mass (278 tons) is under study Advantages: systematic from the determination of the fiducial mass eliminated higher statistics Disadvantage: statistical subtraction of the surface contamination Lowering the threshold down to 2 MeV? In 5 years we can observe at 3s C.L. the transition upturn, comparing the BX rate with E < 5 MeV and the SK-I one with E > 5 MeV Davide Franco – Università di Milano & INFN NOW 2008

(submitted to PRL) Davide Franco – Università di Milano & INFN NOW 2008

Spares Davide Franco – Università di Milano & INFN NOW 2008

8B Spectral Distortion ratio Davide Franco – Università di Milano & INFN NOW 2008