D. Frekers. Charge-exchange reactions GT-transitions, bb-decay b b. and things beyond. n n 13 N 15 O 17F. 7Be. pep. hep

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1 1 AU [cm-1 s-1 MeV-1)] for lines [cm -1 s-1 ] D. Frekers n n Charge-exchange reactions GT-transitions, bb-decay b b and things beyond pp 13 N 15 O 17F 7Be pep neutrino energy [MeV] 8B hep

2 Chargex-reactions ( 3 He,t) & (d, He) highlights & features of nbb nuclear matrix elements (NME) 76 Ge, 8 Se, 96 Zr, 100 Mo, 136 Xe fragmentation smallest/largest NME the 0nbb decay nuclear matrix elements 1 st forbidden NME s and - states n solar SNU rates and ( 3 He,t) reaction 71 Ga( 3 He,t), 8 Se( 3 He,t) the A=96 system Outline the 96 Zr (b-) 96 Nb Q-value and a direct test of 0nbb NME

3 b - b - decay T (even-even) (Z,N) neutron-rich y 0 + nb - b - decay: 0nb - b - decay: T y EC never 0 + (Z+1,N-1) (odd-odd) b - b - b - ph-spc ( ) 5-body 3-body NME allowed 0 + (Z+,N-) any degree i 1 (even-even) 3 ( ph-spc ) mueimi NME en

4 - i - i U V e e diag( 1,, 1) -i Ve1 Ve Ve3 c1c13 c13s1 s13e -i -i V i V 1 V V 3 -c3s1 - c1s13s3e c1c3 - s1s13s3e c13s3 V i i 1 V V s1s3 - c13c3s13e -c1s3 - c3s1s13e c13c3 known quantities: recall: neutrino mass problem 3 i 1 ei NME U m atm ev (0.05eV) m m - m -5 sol ev (0.009eV) m m - m i extra Majorana-Phases

5 neutrino-mass-scenarios: 1) degenerate: m n m 1 m m 3 ) normal hierarchy: m n m 3 m m 1 3) inverted hierarchy: m n m m 1 m 3 m n e 0.eV 3m m m e e n e 1 - i( - 1) - i( - 1) sol ( 0.5) msol e i( 1) atm 3 m m e - - n the best of all cases = ZERO!! for: 3m ( - 1) 1 m sol if inverted hierarchy could be established (LHC, SN-n, precision-oscillation) THEN: mn matm e or neutrino is a Dirac-particle

6 Nucl.MatrixElements nb - b - decay q-transfer like in ordinary β-decay (q ~ 0.01 fm -1 ~ MeV/c) i.e. only allowed transitions possible

7 4 C GF ga ( ) ( ) 7 C DGT ( ) 8 G (Q,Z)!! cos( ) M f( Q ) M ( ) DGT Q 11 Z exp 10-3 MeV extracted from half-life - favorable: 1. high Q-value. large Z unfavorable (but cannot be changed): 1. large neutron excess (Pauli-blocking) p n p n

8 M ( ) DGT (f) (i) 0g.s k k k m m k k k g.s. 1 (f) m Q (0 g.s.) E(1 m ) E0 m m + - m M GT M GT E m to remember: 1. sequential & allowed b - -decays of Gamow-Teller type. 1,, 3,... forbidden decays negligible 3. Fermi transitions do no contribute (because of different isospin-multiplets) Can be determined via chargeexchange reactions in the (n,p) and (p,n) direction ( e.g. (d, He) or ( 3 He,t) )

9 Nucl.MatrixElements 0nb - b - decay neutrino is a virtual particle q~0.5fm -1 (~ 100 MeV/c) (due to Heisenberg q x~ 1 ) degree of forbiddeness is lifted

10 !! (Q,Z) ( ) A ( 0 ) gv ( 0 ) DGT DF ga G g M M m e Q 5 Z 4 10!! to remember: 1. higher-fold forbidden transitions possible. Fermi transitions important 3. Pauli-blocking largely lifted 4. large Q-value, high Z important NOT (easily) accessible via charge-exchange reactions theory largely independent of (A,Z) (except near magic nuclei) mass of Majorana-n!

11 Charge-exchange reactions E/E ~ 5 x10-5 ~ 5 kev at 40 MeV ( 3 He)

12 Q: what is the connection between weak s operator and the hadronic reaction - A: dominance of the Vs effective interaction at medium energies (n,p), q 0!!

13 dσ/dω (GT,q~0) ~j 0 (qr) ~(1- q R )

14 76 Ge N-Z=10 Resolution is the key!!!

15 almost 70!! resolved single states up to 5 MeV identified as GT 1+ transitions!!!

16 ~ 70!! single states up to 5 MeV!!!???? anti-correlation???? is the anti-correlation a property of deformation?? 76Ge moderately oblate/ prolate (b ~ 0.1) 76Se oblate (b ~ -0.)

17 8 Se 0+ b h b- N-Z=14 Qb-b- 99 Qb Q EC Resolution is the key!!! possibly useful for solar neutrino detection

18 10-4 yield/(5 kev msr) 0.36 (3 ) ( - ) ( - ) (1, - ) (1 ) 0.41 (1 ) 1.33 (1 ) (1 ).087 (1 ).136 (1 ).498 (1 ) Se(3He,t)8Br E = 40 MeV E = 38 kev 0.0 < q lab < < q lab < < q lab <.5 IAS Se IAS ~65 J =1 states GTR Ex [MeV] 3 isolated GT transition below MeVfragmentation recedes to GT resonance

19 96 Zr N-Z=16 Remember: B(GT) tot = 3(N-Z) ~ 50! B(F) = (N-Z)

20 ( 3 He,t) (d, He) =0.16 E x (MeV) B(GT - ) = 0.16 T B(GT + ) = 0.3 Fascination: With only 1 state: ( nbb ) (.1 0.4) 10 years calc. 19 1/ T ( nbb (.3 0.) 10 years (NEMO3-result) exp. 19 1/

21 100 Mo N-Z=16 useful as SN neutrino detector (sensitive to n temperature in SN)

22 HERE: almost the entire low-e GT strength is concentrated in the g.s. 100 Mo entire low-energy GT strength is concentrated in a SINGLE STATE and with b - logft known M n (g.s.) M (total) n DGT DGT No need for GT giant resonance

23 64 Zn(ee, eb+) 76 Ge(b - b - ) 8 Se(b - b - ) 96 Zr(b - b - ) 100 Mo(b - b - ) reduced fragmentation of GT strength

24 136 Xe N-Z=8 question: why so stable!!!

25 136Xe

26 What s the size of the NME? T 10 yr ( ) -1 DGT MeV M. all signs positive > B GT 10 B m m GT Bm GT 10!!!! 3

27 A. Poves (simultaneous to our publication): NO CANCELLATION!! there is no B(GT + ) strength, except for lowest 1 + state Recall: 136 Xe is almost doubly magic!! 3x10-3 Shell model provides conclusive explanation for the deemed pathologically long half-life of 136 Xe. Expt l test: 136 Ba(d, He) 136 Cs

28 136 Xe b- b Ba expmt: question: nbb NME is exceptionally small how does the ME scale in the case of 0nbb decay? could it be that: nbb ME is suppressed AND 0nbb ME is enhanced???

29 Experiments towards the 0nbb NMEs Here: - states and occupation vacancy numbers via chargex reactions

30 40.0 Decomposition of M GT Xe g pp = 0.89 g pp = 0.96 g pp = 1.00 g pp = ! 100 Mo Theory: The - strength makes up relative - strength to ~ 5 MeV ~ 0-30% of the 0nbb ME!! Expmt: J. Suhonen, Phys. Lett B607, 87 (005) 136Xe exhibits largest - strength 0nbb ME enhanced?!?!

31 Poves (Poves)

32

33 1 AU [cm-1 s-1 MeV-1)] for lines [cm -1 s-1 ] pp 13 N 15 O 17F 7Be pep 8B hep solar neutrino rates via ( 3 He,t) neutrino energy [MeV] 71 Ga(n,e - ) SNUs from 71 Ga( 3 He,t) 71 Ge charge-ex reaction

34 10 x yield / (5 kev msr) 71 Ga(n,e - ) SNUs from ( 3 He,t) charge-exchange reaction.041 (5/ - ).806 (5/ - ) (1/ -, 3/ - ) g.s., 1/ , 5/ , 3/ , 1/ , 3/ , 3/ , 3/ , 5/ , 5/ , 3/ (5/ - ).35, 5/ x yield / (5 kev msr) IAS Ga(3He,t)71Ge E = 40 MeV DE = 45 kev Qc.m. = Ex[MeV] SNU SNUs from SSM Ex[MeV] 71 Ga(n,e - ) R (stat) 1.1(sys) stat. err. mostly due to CNO n s prev ly:13 ± 18 DF et al, PRC91,015

35 1 AU [cm-1 s-1 MeV-1)] for lines [cm -1 s-1 ] pp 13 N 15 O solar neutrino F 7Be pep 8B rates via ( 3 He,t) 10 hep neutrino energy [MeV] 8 Se(n,e - ) SNUs from 8 Se( 3 He,t) 8 Br charge-ex reaction Advantages: low threshold enhanced sensitivity to pp-neutrinos short life-time against b-decay (35h) pp-n s in real time g-emission, easy to detect

36 8 Se( 3 He,t) spectrum B(GT) SNU Total rate: 58 SNU Population of 1 st 1 + state: 97% pp n fraction: 76%

37 Future perspectives of chargex-reactions bb-decay and nuclear matrix elements Resolution is key issue (RCNP gives the lead!) need 0-30 kev for ( 3 He,t) & (d, He) Need to explore proportionality between chargex x-section and (e.g. - states) in weak interaction (resol n is key) L 0 transitions n-physics and chargex-reactions Hadronic chargex and weak-interaction x-sections are fortuitously connected -- exploit this!! solar neutrinos, SN-neutrinos, element synthesis Need to address quenching issue urgently!! Chargex in inverse kinematics plays a pivotal role (BUT need resolution) EOS and chargex-reaction IAS and GT resonance data needed and useful BUT:theories need to converge on their relevance 71 Ga(n,e - ) R SNU 8 Se(n,e - ) R 58.4 SNU 11