the exo 200 double beta decay experiment and plans for the future n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
The EXO-200 Double Beta Decay Experiment and Plans for the Future PowerPoint Presentation
Download Presentation
The EXO-200 Double Beta Decay Experiment and Plans for the Future

Loading in 2 Seconds...

play fullscreen
1 / 59

The EXO-200 Double Beta Decay Experiment and Plans for the Future - PowerPoint PPT Presentation


  • 102 Views
  • Uploaded on

The EXO-200 Double Beta Decay Experiment and Plans for the Future. David Sinclair Valday 2014. The EXO Collaboration. University of Alabama, Tuscaloosa AL, USA - D. Auty, T. Didberidze, M. Hughes, A. Piepke, R. Tsang

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'The EXO-200 Double Beta Decay Experiment and Plans for the Future' - baylee


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide2

The EXO

Collaboration

University of Alabama, Tuscaloosa AL, USA - D. Auty, T. Didberidze, M. Hughes, A. Piepke, R. Tsang

University of Bern, Switzerland - S. Delaquis, G. Giroux, R. Gornea, T. Tolba, J-L. Vuilleumier

California Institute of Technology, Pasadena CA, USA - P. Vogel

Carleton University, Ottawa ON, Canada - V. Basque, M. Dunford, K. Graham, C. Hargrove, R. Killick, T. Koffas, F. Leonard, C. Licciardi, M.P. Rozo, D. Sinclair

Colorado State University, Fort Collins CO, USA - C. Benitez-Medina, C. Chambers, A. Craycraft, W. Fairbank, Jr., T. Walton

Drexel University, Philadelphia PA, USA - M.J. Dolinski, M.J. Jewell, Y.H. Lin, E. Smith

Duke University, Durham NC, USA – P.S. Barbeau

IHEP Beijing, People’s Republic of China - G. Cao, X. Jiang, L. Wen, Y. Zhao

University of Illinois, Urbana-Champaign IL, USA - D. Beck, M. Coon, J. Ling, M. Tarka, J. Walton, L. Yang

Indiana University, Bloomington IN, USA - J. Albert, S. Daugherty, T. Johnson, L.J. Kaufman

University of California, Irvine, Irvine CA, USA - M. Moe

ITEP Moscow, Russia - D. Akimov, I. Alexandrov, V. Belov, A. Burenkov, M. Danilov, A. Dolgolenko, A. Karelin, A. Kovalenko, A. Kuchenkov, V. Stekhanov, O. Zeldovich

Laurentian University, Sudbury ON, Canada - B. Cleveland, J. Farine, B. Mong, U. Wichoski

University of Maryland, College Park MD, USA - C. Davis, A. Dobi, C. Hall, S. Slutsky, Y-R. Yen

University of Massachusetts, Amherst MA, USA - T. Daniels, S. Johnston, K. Kumar, A. Pocar, D. Shy, J.D. Wright

University of Seoul, South Korea - D.S. Leonard

SLAC National Accelerator Laboratory, Menlo Park CA, USA - M. Breidenbach, R. Conley, A. Dragone, K. Fouts, R. Herbst, S. Herrin, A. Johnson, R. MacLellan, K. Nishimura, A. Odian, C.Y. Prescott, P.C. Rowson, J.J. Russell, K. Skarpaas, M. Swift, A. Waite, M. Wittgen

Stanford University, Stanford CA, USA - J. Bonatt, T. Brunner, J. Chaves, J. Davis, R. DeVoe, D. Fudenberg, G. Gratta, S.Kravitz, D. Moore, I. Ostrovskiy, A. Rivas, A. Schubert, D. Tosi, K. Twelker, M. Weber

Technical University of Munich, Garching, Germany - W. Feldmeier, P. Fierlinger, M. Marino

TRIUMF, Vancouver BC, Canada – J. Dilling, R. Krucken, F. Retière, V. Strickland

outline of talk
Outline of talk
  • Some thoughts on double beta physics
  • Description of the EXO-200 Detector
  • Detection of 2nbb decay in 136Xe
  • Limits on 0nbb decay in 136Xe
  • Plans for the future
2 neutrino double beta decay
2 Neutrino Double Beta Decay
  • Nemo has done a great job of measuring most of the 2 neutrino double beta decay rates
  • 136Xe is an exception because NEMO cannot use a gas source
  • Earlier work suggested limits on the 136Xe rate which would make it exceptionally slow
physics of double beta decay
Physics of double beta decay
  • Understanding Neutrinoless DBD is closely coupled to understanding neutrino masses and mixing
  • We therefore make a diversion to look at what we know
assuming 3 families
Assuming 3 families

(Cosmology favours about 4 but evidence is weakening)

Pontecorvo Maki Nakagawa Sakata Matrix

LBNE

Atmospheric

Minos

T2K

Reactor

T2K

Minos

Solar

Solar

KAMLAND

bb 0n

what do we know about mixing angles
What do we know about mixing angles
  • With good accuracy
  • F12 = 33.8ofrom solar, kamland
  • F23 = 45o from SuperK, Minos…
  • F13= 9o from reactors
  • d CP phase not known
  • a1, a2 Majorana phases not known
slide12

Ofer

Lahav

neutrino mass in the standard model
Neutrino mass in the Standard Model
  • In the standard model neutrino masses are 0
  • Because we only observe left handed neutrinos we cannot form a Dirac mass term this way
  • Possible to form a Majorana mass term
seesaw model
Seesaw Model
  • Neutrino masses are very small because of mR in denominator. mRis at the gut scale
  • If mL is not zero it can dominate and give degenerate neutrino masses
neutrinos and leptogenesis
Neutrinos and Leptogenesis
  • The only neutrinos which can impact the baryon asymmetry are the very heavy right handed neutrinos
  • We would like to understand CP violation in this sector
  • This is far beyond the reach of experimental physics
  • May be related to CP violation in light sector
    • See e.g. Pascoli, Petcov and Riotto, CERN-PH-TH/2006-213
  • This can come from either Dirac CP term d or from the Majorana phases a or both
what would we like to learn about neutrinos
What would we like to learn about neutrinos
  • Determine the mass hierarchy critical
  • Determine d
  • Are neutrinos Majorana
  • Determine the a parameters
  • Show violation of total lepton number
neutrino less double beta decay
Neutrino-less double beta decay
  • Observation of neutrino-less double beta decay would
    • Demonstrate that neutrinos are Majorana particles
    • Demonstrate DL=2 total lepton number violating process
    • Set mass scale for the neutrino
  • Rate is given by
double beta cont
Double Beta (cont.)
  • G is known, scales with E5
  • M is a nuclear matrix element. Calculations are converging (factor of 2)
  • m2bbcontains neutrino mixing information
slide19

Nucl. Phys. B659 359

Dark areas

Show variation due to phases only

Light colours include experimental errors

Assumed q13 =0

slide20

Klapdor-Kleingrothaus Results for Ge

double beta decay

57 kg years of 76Ge data

Apply single site criterion

exo 200
EXO 200
  • Tracking Liquid TPC
  • 200 kg enriched 136Xe
  • Ionization + scintilation
  • No gain in ionization channel – demanding on electronics
  • Lead shield + HFE (heat transfer fluid)
why xenon
Why Xenon
  • Favourable Q value
  • Easy to make very pure
  • Easiest (least expensive!) isotope to produce
  • Possibility of background control through tagging of daughter
what form to use
What form to use?
  • Gas (eg NEXT, Gotthard)
    • Excellent energy resolution
    • Good tracking
    • Detector is large so shielding is more challenging
  • Liquid Scintillator
    • Refer to Kozlov’s talk
  • Liquid Xenon
    • Compact, reasonable resolution, event reconstruction
slide37

EXO-200 has achieved

Very long lifetimes

Supports plans for larger

Detector

new analysis out this week
New Analysis out this week
  • After a lot of work to fully understand the detector response a more precise value has been obtained.
  • T1/2 = 2.172 +-0.017 (stat) +-0.060 (syst)x1021 y
  • Most precisely measured 2 neutrino double beta decay rate to date
  • Possible because of the homogeneous detector design
  • URL: http://link.aps.org/doi/10.1103/PhysRevC.89.015502
  • DOI: 10.1103/PhysRevC.89.015502
slide41

Current state of source

Reproduction

There are no free

Parameters except overall

normalization

exo future
EXO Future
  • Next step will be nEXO
  • 5 T liquid xenon enriched in 136Xe
  • Location likely to be SNOLAB
  • 5T is chosen as the mass required to cover the inverted hierarchy
  • Replace lead with large water shield
slide48

nEXO at SNOLAB

Water

Cryostat

Detector

some changes from exo 200
Some changes from EXO-200
  • Need internal electronics to cut noise
  • Have to deal with heat
  • Go to single ended TPC design to give maximum self-shielded fiducial mass
the big challenge
The Big Challenge
  • The biggest challenge for the project will be securing 5 T of enriched 136Xe
  • Russia is the only country that has the capability of producing such an enormous amount of isotopically separated material
  • We need to look at this project as a global endeavor
tpc or scintillator
TPC or Scintillator?
  • Scintillator can proceed with minor changes to existing detector
  • Good self shielding from clean scintillator
  • Great detector for exclusion limit
  • TPC has better energy resolution (we aim for 1%)
  • TPC gives more handles to discriminate against backgrounds
  • Probably better ability to make discovery
can we reach the normal hierarchy
Can we reach the normal hierarchy?
  • Need to control even better the backgrounds
  • We may be able to tag events with the production of 136Ba
  • Process involves extraction of the Ba ion from xenon, trapping it, and identification by laser spectroscopy
barium tagging
Barium tagging

Requires Ba+ ion

Double beta decay produces Ba++

2P1/2

650nm

493nm

4D3/2

metastable 80s

2S1/2

extraction of ions from gas
Extraction of Ions from gas
  • Test process using atmospheric pressure electrospray source and a quadrupole mass spec
conversion from ba to ba
Conversion from Ba++ to Ba+
  • Pass ions through low pressure TEA
  • TEA has low IP and can give up an electron to Ba++ but not to Ba+
  • Use triple quadrupole system. First quad selects Ba++, second contains the TEA, third analyses the products
  • Conversion efficiency looks very high and no evidence for molecular formation
timescale for next phase
Timescale for Next Phase
  • EXO is taking 0 neutrino search data now
  • Will probably reach background limit in couple of years
  • DOE has indicated it wants to make a decision on next generation detector in ~ 2 years
  • We need to have a developed proposal on this timescale