1. LENS—Overview R. S. Raghavan Virginia Tech LONU-LENS Mini Workshop Oct 14, 2006

2. SSM Prediction Directly measured so far Directly measured Neutrino beams from SUN Very Low Energy Pure Favor ( e ) Largest Fluxes Longest Base Line Largest Intervening Mass Highest Magnetic Fields Unique Machine for Exploration of Neutrino Phenomenology in Vacuum, Matter & Magnetic Fields STATUS: From High Energy Nus ( 8 B & Atmos) Non-zero Neutrino Mass  Neutrino Flavor Conversion NEXT…Door open to Explore New Physics & Astrophysics New Quest: Discoveries beyond Oscillations- New Paradigm: Precision Data, solar model independence New Frontier: < 2 MeV  Central Objectives of LENS The New Frontier Solar Neutrinos-Past & Future

3. Tagged ν –capture reaction in Indium  LENS is the only developed CC real time detector for solar neutrinos Unique: Specifies ν Energy E ν = E e + Q  Complete LE nu spectrum Lowest Q known  114 keV  access to 95.5% pp nu’s Target isotopic abundance ~96% Powerful delayed coinc. Tag Can suppress bgd =10 11 x signal Downside: Bgd from 115 In radioactivity to ( pp nu’s only)  rate= 10 11 x signal Tools: 1. Time & Space coinc.  Granularity (10 6 suppression) 2. Energy Resolution In betas <500 keV; ∑ Tag = 613 keV 3. Other analysis cuts signaldelayTag cascade

4. Indium Solar Neutrino Detection—R&D History Hi Granularity(~10 9 ) --Lo precision pp (3σ) Tagged pp reaction in Indium RSR-PRL 1976 Bell Labs (rsr, Pfeiffer, Mills) 1976-79 pp InLS/Plastic Sandwich Indium β-spectrum Bell Labs-MIT (rsr, Deutsch) 1979-84 pp Plastic/Quartz Fiber Scint Oxford (Booth) 1978-90 pp Indium Tunnel Diodes CEA Saclay (Cribier, Spiro) 1979-81 pp Hybrid TPC/Plastic Penn-Coll de France-KEK-BL-TUM 1987-89 Be InLS (KEK- Suzuki, Inoue) Borexino 1989 - Be ν- e-scattering –no tag  Brute force reduction of bgd via invention of new ultrapurity chemistry New tgged pp capture reactions—non radioactive targets –RSR-PRL 1997 LENS R&D LNGS-EU-Russia-USA 1999-01 pp Yb, Gd, Se –YbLS Lo Granularity (10 5 ) —Hi Precision pp (3%) ( SNO result ! ) RSR-hep-ph/010605 LENS R&D LNGS-- 2001-03 pp In InLS LENS-Sol/CAL 2004- Nu Lum InLS (LENS-Sol) Plastic Sandwich (LENS-Cal)

5. Status Fall ‘03* Status Summer ‘05 Design of DetectorLongitudinal Modular Cubic Lattice Chamber CompositionHybrid: InLS+ pure LS Homogeneous: InLS only In content Light attenutation L(1/e) Signal Eff Pe/MeV 5% 1.5m 230 >8% >10m 900 Indium Mass(1900 pp/5y) 30 ton10 ton Total Mass6000 ton125 ton PMT’s200,00013,300 Neutrino detection eff.20%64% S/N (β+γ Bremms. Only (All In decay modes) ~1 ~0.04 ~75 ~3 *MPIK talk at DPG Mtg Berlin 03/04 Major Progress from LENS LNGS  LENS Sol Hi Quality InLS Developed Background Analysis Insights New Detector Design Invented 8.6 m after 8 months Transparency of InLS

6. Expected Result from LENS Background precisely and concurrently measured Well resolved low energy solar nu spectrum –  pp, 7 Be, pep, CNO with 99+% of solar nu flux  Solar luminosity in nu’s  pp spectral shape accessible for first time

7. pp Spectral Shape  New Science Goal  Directly Probe Temperature Profile of Energy Production in the Sun by experimentally measuring the Gamov Energy Shift in pp Fusion (not observed in laboratory so far) Experiments focused so far on fluxes, not (absolute) energies of solar nu’s -- --not possible via electron scattering or radiochemistry  need energy specific CC detection technology -  LENS Energies of neutrinos from Fusion reactions are usually taken from exothermal energy release (Q value i.e. difference of initial and final masses) e.g. p + p  d + e+ + ν e (420 keV max); p + e- + p  d + ν e (1442 keV) This does not include the kinetic (Gamov) energy needed to initiate pp fusion Gamov Energy E 0 (T) is temperature dependent E (T) is added to the pp and pep energy spectra weighted by the fraction of the flux produced at that temperature---E is typically ~5 keV i.e. pp  425 keV and pep  1447 keV Can one observe the Gamov shift by measuring pp and pep energies? If so---we can directly measure the  temperature profile of energy production by pp fusion

8. q (lab) keV +Δ keV +δ keV +ΔE keV + δ E keV pp 420.2 a 3.41 b 1.6 5.2 c 1.7 pep1442.26.65 b 4.54 7 Be861.81.29 b 0.81 aMaximum energy; bShift of mean energy of signal spectrum in the detector, in the case of pp in the energy range keV ; cShift of maximum energy in sun. The  E includes likely systematic errors (see text) σ = 1.63 keV P lab (q,Qs) ~ q 2 p W F(Z,W,Qs) (Z= -1 ) (Z=50) Sn Grieb/RSR hep-ph/0609030 Sun: Target: Fit measured spectrum to P sun leaving q max free Find δE from repeated trials; compare to predicted ΔE

9. Science from Neutrino Flux Data Basic Dichotomy in Solar neutrino Research: Measured Fluxes vs Unknown Original Fluxes in sun All science interpretations need ORIGINAL fluxes Usual Practice: Appeal to predictions of Standard Solar Model How to make inferences completely free of models? First Breakthrough: Made by SNO in the case of 8 B flux  Single solar source  8B  SNO, SK  Measured 8B NC “flavor-blind” flux  original flux in sun  SK CC+NC spectrum –flavor survival independent of energy  Kamland data with ANTINEUTRINOS  LMA matter conversion at 8 B neutrino energies (~10 MeV) Major Questions: 1)Conclusion assumes CPT invariance. Is This Correct ?–First opportunity to Test this for NEUTRINOS 2) LMA if true, predicts different type of conversion at LOW ENERGIES Verify this: Beyond LMA  Discovery ! Imperative to test 1) and 2):

10. Major Questions: 1) CPT invariance for NEUTRINOS 2) LMA prediction of different type of conversion at LOW ENERGIES 3) Deviations from LMA predictions  Discovery Imperative tests HOW to attack the problem on a model independent basis?  Model Independent Fluxes at LOW ENERGIES ? Basic Need: Fluxes of single sources  Well identified and resolved Spectroscopic data  Removal of precisely measured background  Requires CC based Low Energy Detection  Developed only in LENS Scattering Spectrum (CLEAN)Absorption Spectrum (LENS) Bgd Est.Bgd measured

11. Solar Luminosity from Low Energy Neutrino Flux data from LENS Use Best Known Neutrino Model (e.g. LMA) to reverse calculate original Fluxes from measured fluxes of INDIVIDUAL sources:  pp, Be, pep & CNO, constitute 99+% of solar neutrino flux  Calculate Energy by weighting fluxes with coefficients of energy released in each solar reaction (Bahcall, Phys. Rev C 65 (2002), 025801)  Solar Luminosity in Neutrinos L(ν inferred) From Solar Constant  Solar Luminosity in Photons L(hν) Energy Match from two probes: L(ν inferred) / L(hν) = 1.00 This tests if the neutrino model used is CORRECT  No SSM used; Inference only via measured quantities Present Status after 40 years of Solar nu research: L(ν inferred) / L(hν) = 1.4 (+0.2-0.3; 1 σ)( +0.7-0.6; 3σ) Bahcall & C. Penya-Garay, JHEP 4, 0311 (2003); R.G.H. Robertson, Prog. Part. Nucl. Phys. 57, 90 (2006) suggests Lν /L (hν) ~1.12±0.2.  Wide Room For Surprises  Neutrinos notorious for Surprises !

12. New Global Analysis using: Data from LENS: Measured v Fluxes of pp, Be, pep, CNO  Solar Luminosity in Neutrinos Temperature of sun via Gamow shift ; Data from SNO 8 B flux (CC and NC) ; SK data on spectrum Match to Measured Photon Luminosity by varying ν parameters (use the temperature shift to test SSM prediction of dependence of of pp flux on T (  (1-0.08(T/TSSM)-1.1) J. N. Bahcall & A. Ulmer, Phys. Rev. D53, 4202 (1996). This global analysis ASSUMES: 1) Nuclear Reactions SOLE source of Sun’s Energy 2) Quasi hydrostatic Equilibrium  Neutrino Luminosity Now = Photon Luminosity Now from Energy created 10 5 years ago

13. Be/pp ~5% pep/pp~9% Be/pp ~18% pep/pp~40% With Precise Model Independent pp, Be,pep fluxes: Energy Dependence of Survival Probabilities: Test LMA, NSI, MVA, Measure θ 12 Precisely e) LMA Precision θ 12 Mass Var. Nu’s NSI Sterile Nu

14. LENS TECHNOLOGY INTRODUCES Recipe for Discovery in Particle Physics --CPT, NSI, MVN, Θ 12, Θ 13 from absolute energy Astrophysics of Sun –CNO,Hidden sources of energy, Past Sun vs Present Sun, Temp of pp fusion (test SSM) A new comprehensive approach for model independence : Measuring the Solar Luminosity in Neutrinos and comparing it directly with the Photon Luminosity Conclusion

15. Russia INR (Moscow): I. Barabanov, L. Bezrukov, V. Gurentsov, V. Kornoukhov, E. Yanovich IPC (Moscow): N. Danilov, G. Kostikova, Y. Krylov INR (Troitsk) I: J. Abdurashitov, V. Gavrin. et al. II: V. Betukhov, A. Kopylov, I. Oriachov, E.Solomontin U. S.: BNL: R. L. Hahn, M. Yeh UNC: A. Champagne ORNL: J. Blackmon, C. Rasco, Qinlin Zeng, A. Galindo-Uribarri Princeton U. : J. Benziger SCSU: Z. Chang Virginia Tech: C. Grieb, J. Link, M. Pitt, R.S. Raghavan, R. B. Vogelaar, LENS-Sol / LENS-Cal Collaboration (Russia-US: 2004-)