neutrinoless double beta decay

18 Feb. 2005, E.J.Chun, KIAS18 Feb. 2005, E.J.Chun, KIAS Workshop for Underground Experiment and AstrWorkshop for Underground Experiment and Astroparticle Physics, Muju, 2005. 2. 16-19oparticle Physics, Muju, 2005. 2. 16-19

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Neutrinoless Double BetNeutrinoless Double Beta Decaya Decay

Eung Jin ChunEung Jin ChunKorea Institute for Advanced StudyKorea Institute for Advanced Study

APS neutrino study: physics/0411216APS neutrino study: physics/0411216 hep-ph/0412300hep-ph/0412300 Bilenky, et.al., hep-ph/0402250Bilenky, et.al., hep-ph/0402250

18 Feb. 2005, E.J.Chun, KIAS Workshop for Underground Experiment and Astroparticle Physics, Muju, 2005. 2. 16-19

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Key questions by theoristsKey questions by theorists APS neutrino study: physics/0411216APS neutrino study: physics/0411216

►Are neutrinos their own anti-particles?Are neutrinos their own anti-particles?►What is the pattern of neutrino masses?What is the pattern of neutrino masses?► Is there CP violation in the leptonic sector? Is there CP violation in the leptonic sector?

-- -- Possibly the origin of the matter-antimatter asymmetry of the universPossibly the origin of the matter-antimatter asymmetry of the universe?e?

►Are there additional neutrino species as may Are there additional neutrino species as may be hinted by the LSND experiment?be hinted by the LSND experiment?


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Majorana(Majorana( = = cc) or Dirac() or Dirac( cc)?)?L L 0 or 0 or L= 0 L= 0

► Neutrinoless double beNeutrinoless double beta decay (0ta decay (0))

► Beta decayBeta decay

ppnn

nn pp

ppnn

nn pp

e-e-

e-e-

e-e-

mm

e-e-


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Neutrino mass patternsNeutrino mass patterns

mm = 0.1-0.5 eV = 0.1-0.5 eV : : QQuasi-uasi-DDegenerate egenerate cosmologiccosmological massal mass – – 200 kg200 kg of isotope of isotope

mm = 0.02-0.05 eV = 0.02-0.05 eV : : IInverted-nverted-HHierarchy ierarchy oror QD with QD with NNormal-ormal-HHierarchy ierarchy atmospheric neutrino massatmospheric neutrino mass – – 1 ton1 ton

mm = 2-5 meV = 2-5 meV : QD, IH, NH : QD, IH, NH solar neutrino masssolar neutrino mass – – 100 tons100 tons


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Tritium beta decay Tritium beta decay mmee

< 2.2 eV < 2.2 eV at Mainz & Troitsk at Mainz & Troitsk


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Cosmolgy Cosmolgy

► Neutrino dark matter (hot)Neutrino dark matter (hot) hh22 = = ii m mii/92.5 eV/92.5 eV► Power spectrum of small scale structure Power spectrum of small scale structure ddFS FS (Gpc) (Gpc) »» 1/m 1/m (eV) (eV)

* current bound : * current bound : ii m mii < 0.2-0.6 eV < 0.2-0.6 eV

* future sensitivity : 0.14 eV (Planck)* future sensitivity : 0.14 eV (Planck)


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( Astrophysics )( Astrophysics ) physics/0411216physics/0411216

► Detection of the GZK neutrinosDetection of the GZK neutrinos (E(E > 10 > 101515 eV), produced from the interactio eV), produced from the interactio

ns of UHECR protons with CMBRns of UHECR protons with CMBR► $10 million to enhance radio-based technol$10 million to enhance radio-based technol

ogies or develop new technologies reaching ogies or develop new technologies reaching 10 x sensitivity.10 x sensitivity.


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( An astrophysical neutrino flux model )( An astrophysical neutrino flux model )


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Neutrino mases and mixingNeutrino mases and mixingll = = I I U Uli li eeiii/2i/2 ii

l = e, l = e, , , and i = 1, 2, 3 and i = 1, 2, 3 three angles: three angles: ijij; three phases: ; three phases: 1,21,2, , ; ;

three masses: three masses: mmii


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00 & & decay and oscillations decay and oscillations

APS 0APS 0 study : hep-ph/0412300 study : hep-ph/0412300

► P(P(ll -> -> kk) = ) =

sinsin2222 sin sin22[1.27[1.27mm22ijij(eV(eV22)L(km)/E(GeV)])L(km)/E(GeV)]

► decay : decay : mmee = [ = [ ii |U |Ueiei||22mmii

22]]11/2/2

►decay : decay : mm = | = |ii U Ueiei22 m mii e eiiii | |


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Oscillation parametersOscillation parameters SK,K2K,SNO,KamLAND,CHOOZSK,K2K,SNO,KamLAND,CHOOZ

► mm222121 = 8.2 = 8.2 ££ 10 10-5-5 eV eV22

1212 = 32.3 = 32.3oo

► || m m223232| = 2.0 | = 2.0 ££ 10 10-3-3 eV eV22

sinsin22222323 > 0.94 > 0.94► sinsin22221313 < 0.11 < 0.11

QD: m0 ¼ m3,2,1NH: NH: mm22

3232 > 0 (m > 0 (m33 > m > m22 > > mm11) ) IH: IH: mm22

3232 < 0 (m < 0 (m22 > m > m11 > > mm33))

+0.6-0.5

+0.6-0.4

+2.7-2.4


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Ranges of mRanges of m

►NH: mNH: m = |[ = |[ m m22SS]]1/21/2 s s1212

22 c c232322

+[+[ m m22AA ] ]1/21/2 s s1313

22 e e-i-i22||

► IH: mIH: m = [ = [ m m22AA]]1/21/2 c c1313

2 2

££[1-4s[1-4s121222cc1212

2 2 sinsin22((22--11)/2])/2]1/2 1/2

►QD: mQD: m=m=m00 |(c |(c121222eeii11+s+s1212

22eeii22)c)c13132 2

+s+s131322||


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Ranges of mRanges of m


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00 and nuclear structure and nuclear structure

► Decay rate of (A, Z) -> (A, Z+2) e+ e+ : 1/TDecay rate of (A, Z) -> (A, Z+2) e+ e+ : 1/T00

1/21/2(A,Z) = (A,Z) =

GG00(E(E00,Z) | M,Z) | M00GTGT – (g – (gVV

22/g/gAA22) M) M00

FF | |22 m m22

► Heidelberg-Moscow Heidelberg-Moscow 7676Ge experiment : Ge experiment : TT00

1/21/2 > 1.9 10 > 1.9 102525 yrs yrs !! mm < 0.55 eV < 0.55 eV


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Nuclear structure issuesNuclear structure issues

► QQuasiparticle uasiparticle RRandom andom PPhase hase AApproximation (10%?)pproximation (10%?)► Shell ModelShell Model► Constraining with other observablesConstraining with other observables► Reducing the uncertainty (factor 2-3 presently) :Reducing the uncertainty (factor 2-3 presently) :


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Future prospectsFuture prospects Bilenky et.al., hep-ph/0402250Bilenky et.al., hep-ph/0402250


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(note) Beta decay : m(note) Beta decay : mee < 0.2 eV at KATRIN < 0.2 eV at KATRIN


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ConclusionsConclusions hep-ph/0412300hep-ph/0412300

neutrinoless double beta decay

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