 angular correlations LPC-Team : G. Ban, G. Darius, P. Delahaye, D. Durand, X. Flechard, M. Herbane, M. Labalme, E. Liénard, F. Mauger, A. Mery, O. Naviliat, D. Rodriguez

Allowed transitions, unpolarized nuclei a e – angular correlationFiertz interference J.D. Jackson, PR106(1957) & NP4(1957) a SM V – A theory |C i |= |C’ i | real Pure Fermi decay SMS_/T_Interaction a F (C V,C S )+1-1 Pure G-T decay a GT (C A,C T ) -1/3+1/3 New Physics beyond the Standard Model Deviations

Any observable linked to  will be sensitive to a Recoil ion momentum   p r (MeV/c) T e (MeV) 6 He 46 V  = 180°  = 0° a GT = -1/3 a F = +1

pure Fermi or G-T transitions a ~ a SM (1-  ) F : a SM = 1  = (|C S |²+|C S ’|²)/C V ² GT : a SM = -1/3  = (|C T |²+|C T ’|²)/C A ² Most precise measurements  C A M GT /C V M F x = 1/(1 +  ² ) 6 He 32 Ar

Present limits a GT = ± (1  ) C.H. Johnson, PR 132 (1963) 1149 Method : Analysis of the recoil energy spectrum a F = ± (1  ) Method : Analysis of the energy spread of the delayed protons E.G. Adelberger, P.R.L. 83 (1999)  C C A T 08.0  C C V S 6 He 6 Li +  - + e (0 + ) GT (1 + ) 32 Ar 32 Cl* +  + + e (O+) F (O+) 31 S + p (3.35 MeV)

SPIRAL BEAMSSPIRAL BEAMS

Pure GT transition 100% G.S. to G.S. T 1/2 = ms Q  = 3.51 MeV, T max = 1.4 keV High production rate : ions/s Goal : improvement of Johnson 1963 experiment build the kinematics event/event adapted environment : Paul trap  - recoil ion coincidences measurements 6 He

Paul trap no magnetic field ions « at rest » in vacuum ions well localized open geometry : high detection solid angle 12 34

Coincidences measurement back-to-back geometry  CP + Delay line anode Plastic + PSD Si Position and Energy Position and Time of flight Injection T x1 T x2 T y1 T y2  e-e- ion

Production SPIRAL: ions/s Efficiencies  RFQ cooler buncher : 20%  Paul trap : 10%  Efficiency of the detection setup : 2.8 ‰  Cycle efficiency: 3.3 ‰ (100ms – limit of 10 5 ions per cycle into the RFQ cooler buncher)  Radioactive decay: 86% One week of data taking 10 7 coincident events to get  a /a = 5 ‰ First LIRAT accepted by the PAC

8 He Pure GT transition, 84 % E  = keV,  = 8 fs T 1/2 = 119 ms Q  = 9.67 MeV, T max = 6.9 keV Production rate : ions/s Doppler shift of  energy linked to 8 Li recoil motion 18 Ne Pure F transition, 7.7 % E  = keV,  = 1.8 fs T 1/2 = 1672 ms Q  = 2.38 MeV, T max = 0.24 keV a F = 1.06 ± 0.19 (2  ) [ events] V. Egorov, NPA621(1997)745

Doppler shift measurement 2 = 2E  ( / M ion c) (0°,180°) = E  ( / M ion c) (eV) T e (MeV) 18 Ne a F =+1 a F =-1 V. Vorobel, EPJA16(2003)139 z

2 (eV) T e (MeV) a GT =+1/3 a GT =-1/3 18 Ne 8 He 8 He vs 18 Ne Q  = 9.67 MeV T max = 6.9 keV E  = keV  = 8 fs Q  = 2.38 MeV T max = 0.24 keV E  = keV  = 1.8 fs enhanced sensitivity !  = 8 fs = 33 Å  T ~ 400 eV in Carbon Paul trap Injection  e-e-  HPGe

32 Ar Pure F transition, 23 % T 1/2 = 98 ms E p = 3.35 MeV,  = 20 eV Q  = 5.1 MeV, T max = 0.52 keV Production rate : ions/s Goal : improvement of ISOLDE 1999 experiment measurement of p energy shift instead of broadening less sensitive to 32 Ar mass (~ factor 5)  - p coincidences measurements

p kinematic shift feasability tests performed in SIRa experiment accepted in GANIL, identification station (coll.: Argonne, Dubna, Louvain-la-Neuve, Leuven) unfortunately not still scheduled … Ar/s, clean beam - ions implanted in carbon foil - p &  detected by Si telescopes

32 Ar ISOLDE experiment results : some key stages…  performed in 1999 M exp ( 32 Ar) = ± 50 keV : a F ~ 1.00 ± 0.06 (1  ) M IMME ( 32 Ar) = ± 3.2 keV :a F = ± (1  ) E.G. Adelberger, PRL83(1999) welcome new measurement with alternative method !  end 2001 : precise ISOLTRAP of 32 Ar mass M exp ( 32 Ar) = ± 1.8 keV K. Blaum, PRL91(2003) Consistent with M IMME, lower uncertainty …! real new challenge ….  a few 10 5 events in p peak need to get  a = (1  )  clean beam with good emittance is needed  experiment could be LIRAT with RFQ in continuous mode

Connected experiments – spectroscopic information  32 Ar : precise mass measurement  C A M GT /C V M F    (ft) -1 & t = T 1/2 (1 +  EC )/BR a mixed = ± (3.6  from SM) N.D. Scielzo, PhD Thesis, Berkeley (2003)  21 Na : precise branching ratio measurement precise a …. … or precise aspectroscopic information  33 Ar : mixed transition B(GT)/B(F) (Shell-model : 0.055…)a mixed = ± 0.004B(GT)/B(F) = ± A. Garcia, hyp.Int.129(2000) (not more valid …!)

Conclusions   angular correlations measurement : still an up-to-date subject  LIRAT-SPIRAL : place of high exotic beam production & some exotic noble gazes are the present best candidates for  angular correlations measurements constraints on exotic weak couplings could be LIRAT  Experiments sometimes linked to reliable spectroscopic data