LENS—Overview

R. S. RaghavanVirginia Tech

LONU-LENS Mini WorkshopOct 14, 2006

SSM Prediction

Directly measured so farDirectly 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 ofNeutrino Phenomenology inVacuum, Matter & Magnetic Fields

STATUS:From High Energy Nus ( 8B & Atmos) Non-zero Neutrino MassNeutrino Flavor Conversion NEXT…Door open to ExploreNew 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

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

SnSneIne115*115115 2

Tagged ν –capture reaction in IndiumLENS is the only developed CC real time detector for solar neutrinos

Unique:• Specifies ν Energy

Eν = Ee + 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 =1011 x

signalDownside:• Bgd from 115In radioactivity to ( pp nu’s only) rate= 1011 x

signalTools:1. Time & Space coinc.

Granularity (106suppression)2. Energy Resolution In betas <500 keV; ∑Tag =

613 keV3. Other analysis cuts

signal delay Tag cascade

Indium Solar Neutrino Detection—R&D History

Hi Granularity(~109) --Lo precision pp (3σ)

Tagged pp reaction in Indium RSR-PRL 1976Bell Labs (rsr, Pfeiffer, Mills) 1976-79 pp InLS/Plastic Sandwich Indium β-spectrum Bell Labs-MIT (rsr, Deutsch) 1979-84 pp Plastic/Quartz Fiber ScintOxford (Booth) 1978-90 pp Indium Tunnel DiodesCEA Saclay (Cribier, Spiro) 1979-81 pp Hybrid TPC/PlasticPenn-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 1997LENS R&D LNGS-EU-Russia-USA 1999-01 pp Yb, Gd, Se –YbLS Lo Granularity (105) —Hi Precision pp (3%) (SNO result ! )

RSR-hep-ph/010605LENS R&D LNGS-- 2001-03 pp In InLS LENS-Sol/CAL 2004- Nu Lum InLS (LENS-Sol) Plastic Sandwich (LENS-Cal)

  Status Fall ‘03*

Status Summer ‘05

Design of Detector Longitudinal Modular

Cubic Lattice Chamber

Composition Hybrid: InLS+ pure LS

Homogeneous: InLS only

In contentLight attenutation L(1/e)

Signal Eff Pe/MeV

5% 1.5m

230

>8% >10m900

Indium Mass(1900 pp/5y)

30 ton 10 ton

Total Mass 6000 ton 125 ton

PMT’s 200,000 13,300

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 < Towards Hi Precision pp >• Hi Quality InLS Developed• Background Analysis Insights• New Detector Design Invented

UV/Vis absorbance of zVt45 (pH 6.88) with time

-0.01

0

0.01

0.02

0.03

0.04

0.05

350 390 430 470 510 550 590 630 670l (nm)

Nor

mal

ized

Abs

orb

ance

10/06/05

01/23/06

03/22/06

05/31/06

8.6 m after 8 months

Transparency of InLS

Expected Result from LENS

• Background precisely and concurrently measured

• Well resolved low energy solar nu spectrum –

pp, 7Be, pep, CNO with 99+% of solar nu flux

Solar luminosity in nu’s pp spectral shape

accessible for first time

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+ + νe (420 keV max); p + e- + p d + νe(1442 keV)

This does not include the kinetic (Gamov) energy needed to initiate pp fusion• Gamov Energy E0 (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. pp425 keV and pep1447 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

pp

pep

Eo

pp

pep

Eo

pp

pep

Eo

q (lab)keV

+Δ<E>keV

+δ<E>keV

+ΔEkeV

+ δ E keV

pp 420.2a 3.41b 1.6 5.2c 1.7

pep 1442.2 6.65b 4.54

7Be 861.8 1.29b 0.81

aMaximum energy; bShift of mean energy of signal spectrum in the detector, in the case of pp in the energy range <110-340> keV ; cShift of maximum energy in sun. The E includes likely systematic errors (see text)

σ = 1.63 keV

P lab (q,Qs) ~ q2 p W F(Z,W,Qs) (Z= -1 )

pp

TdTEQqPqP ppslabsun

)())(,()( 0

dqWZWpFqPdEEN sun ),()(~)((Z=50) Sn

Grieb/RSR hep-ph/0609030

Sun:

Target:

Fit measured spectrum to Psun leaving q max freeFind δE from repeated trials; compare to predicted ΔE

Science from Neutrino Flux Data

Basic Dichotomy in Solar neutrino Research: Measured Fluxes vs Unknown Original Fluxes in sun All science interpretations need ORIGINAL fluxesUsual 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 8B fluxSingle solar source 8B SNO, SKMeasured 8B NC “flavor-blind” fluxoriginal flux in sunSK CC+NC spectrum –flavor survival independent of energyKamland data with ANTINEUTRINOS

LMA matter conversion at 8B neutrino energies (~10 MeV)

Major Questions: 1) Conclusion assumes CPT invariance. Is This Correct ?–First opportunity to Test this for NEUTRINOS2) LMA if true, predicts different type of conversion at LOW ENERGIES Verify this: Beyond LMA Discovery !

Imperative to test 1) and 2):

Major Questions: 1) CPT invariance for NEUTRINOS2) LMA prediction of different type of conversion at LOW ENERGIES3) Deviations from LMA predictions DiscoveryImperative 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 DetectionDeveloped only in LENS

Scattering Spectrum (CLEAN) Absorption Spectrum (LENS)

Bgd Est. Bgd measured

Solar Luminosity from Low Energy Neutrino Flux data from LENS

Use Best Known Neutrino Model (e.g. LMA) to reverse calculate originalFluxes from measured fluxes of INDIVIDUAL sources: pp, Be, pep & CNO, constitute 99+% of solar neutrino fluxCalculate 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 ConstantSolar 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 CORRECTNo SSM used; Inference only via measured quantitiesPresent 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 !

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• 8B 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 Energy2) Quasi hydrostatic Equilibrium Neutrino Luminosity Now = Photon Luminosity Now from Energy created 105 years ago

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 θ12 Precisely

e)LMA

Precision θ12

Mass Var. Nu’s

NSI Sterile Nu

LENS TECHNOLOGY INTRODUCES

Recipe for Discovery in

Particle Physics --CPT, NSI, MVN, Θ12 , Θ13 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 andcomparing it directly with the Photon Luminosity

Conclusion

Russia INR (Moscow): I. Barabanov, L. Bezrukov, V. Gurentsov,

V. Kornoukhov, E. YanovichIPC (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. YehUNC: A. ChampagneORNL: J. Blackmon, C. Rasco, Qinlin Zeng, A. Galindo-UribarriPrinceton U. : J. BenzigerSCSU: Z. ChangVirginia Tech: C. Grieb, J. Link, M. Pitt, R.S. Raghavan, R. B. Vogelaar,

LENS-Sol / LENS-Cal Collaboration(Russia-US: 2004-)