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Tests of symmetries with nuclei (in nuclear  decay) Oscar Naviliat-Cuncic LPC-Caen, (ENSI–CNRS/IN2P3) and Université de Caen Basse-Normandie Caen, France.

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Presentation on theme: "Tests of symmetries with nuclei (in nuclear  decay) Oscar Naviliat-Cuncic LPC-Caen, (ENSI–CNRS/IN2P3) and Université de Caen Basse-Normandie Caen, France."— Presentation transcript:

1 Tests of symmetries with nuclei (in nuclear  decay) Oscar Naviliat-Cuncic LPC-Caen, (ENSI–CNRS/IN2P3) and Université de Caen Basse-Normandie Caen, France

2 2MESON 2010, Cracow, June 10-16, 2010 O. Naviliat-Cuncic Goal and Outline 1. General context 2. Tests of Maximal parity violation 3. Tests of Time Reversal Invariance 4. Searches for other exotic interactions 5. Summary Review achievements of precision measurements in nuclear beta decay aiming to test fundamental symmetries. Present (selected) ongoing projects. (Biased choice)

3 3MESON 2010, Cracow, June 10-16, 2010 O. Naviliat-Cuncic Context and motivations evidence for “new physics” is expected to manifest itself either at the high energy frontier (direct production of new particles) or at the high precision frontier (search for tiny effects). effects have to be looked for everywhere where improvements in experimental sensitivities are possible (atoms, nuclei, particles) (unless strong theoretical counter arguments) consider here experiments in nuclear beta decay (including neutron)

4 4MESON 2010, Cracow, June 10-16, 2010 O. Naviliat-Cuncic Beta decay correlations What we imagine to occur (at the quark-lepton level) ee pepe PpPp JnJn p What we have access to (experimentalist toolbox) 1. Integrate over all vectors: decay rates or lifetimes 2. Integrate/average over all spin vectors: angular correlation 4. Integrate (less) spins and momenta: triple correlations 3. Integrate some spins and momenta: pseudo-scalar correlations a, A, G, D, R contain the dynamics and probe the symmetries

5 5MESON 2010, Cracow, June 10-16, 2010 O. Naviliat-Cuncic 1. Parity violation axial vector J → J (invariant) polar vector p → -p (changes sign) P is assumed to be maximally violated in the SM Searching for deviations probe new physics (like RHC) Look at pseudo-scalar quantities ( J · p ) "decay asymmetry"  · p ) "longitudinal polarization" P space inversion r → -r Terms in the decay rate distribution that change sign under parity …Enhanced sensitivity if one combines both of them

6 6MESON 2010, Cracow, June 10-16, 2010 O. Naviliat-Cuncic Polarization-Asymmetry correlation …and look for deviations from SM Perform relative measurement at different emission angles H.A. Tolhoek and S.R. DeGroot Physica 17 (1951) 1 Absolute  longitudinal polarization from polarized nuclei “Beta particles from polarized nuclei should be polarized” (within V-A) A asymmetry parameter J degree of nuclear polarization  angle between J and p e J beta polarimeter  nuclear spin 

7 7MESON 2010, Cracow, June 10-16, 2010 O. Naviliat-Cuncic Measurement in 12 N decay (LLN, ETH-Zurich, Wisconsin, Leuven) production: Stack Target reaction chamber 10 cm TDC  start stop spectrometer polarimeter  B MgO powder Decay(R-1)x10 4 Lab. 107 In740±410LLN '93 12 N6±34PSI '01 Results [E. Thomas et al., NP 694 (2001) 559] Can be considered as the most precise tests of maximal parity violation in nuclear beta decay (in terms of constraints on RHC) polarization analysis: time resolved spectroscopy of hf Ps decay

8 8MESON 2010, Cracow, June 10-16, 2010 O. Naviliat-Cuncic (Slow) progress on constraints: global fits Severijns, Beck, Naviliat-Cuncic, 2006 RMP 78 (2006) 991 Boothroyd, Markey, Vogel, 1984 PRC 29 (1984) 603 Maximal parity violation implies C’ V = C V = 96 data values 96-(61+13)+34 = 56 data values

9 9MESON 2010, Cracow, June 10-16, 2010 O. Naviliat-Cuncic Neutrino asymmetry: K MOT at TRIUMF B =  0.755(24) [D.Melconian et al., PLB 649 (2007) 370] Pioneering work on 38m K atom trapping Measured the  angular correlation in 38m K Extended setup to polarize 37 K Detect recoiling ions in coïncidence Top view Side view Not competitive yet with present constraints. Setup has been upgraded: new beta detectors, larger chamber,… New data expected soon. J pvpv D.Melconian, J.Behr & Co

10 10MESON 2010, Cracow, June 10-16, 2010 O. Naviliat-Cuncic 2. Time reversal invarianceT Time reversal t → -t axial vector J → -J (changes sign) polar vector p → -p (changes sign) T violation = CP violation In processes involving the lightest quarks, the CKM CP violating effect is strongly suppressed (out of experimental reach) Large window for new physics (provided FSI effects are accounted for) P-even, T-odd correlation: P-odd, T-odd correlation: Do not probe the same physics (mixed) (GT and mixed)

11 11MESON 2010, Cracow, June 10-16, 2010 O. Naviliat-Cuncic R in a mixed transition : neutron at PSI MWPC scintillator Pb-foil 50 cm (Cracow, PSI, Caen, Leuven, Katowice) lead by Prof. K.Bodek & Co Tracking of electrons in low-mass, low-Z MWPC Identification of Mott events by vertex Frequent neutron spin flipping and foil IN/OUT Maximum sensitivity for mutually perpendicular vectors Polarized cold neutrons Transverse polarization analysis by Mott scattering on Pb-foil

12 12MESON 2010, Cracow, June 10-16, 2010 O. Naviliat-Cuncic R in a mixed transition : neutron at PSI Pb-foil Vertex identification [A. Kozela at al., PRL 102 (2009) ] Analysis in terms of geometric form factors averaged over the setup geometry Example of data sample R exp = 0.008(16) N exp = 0.056(12) R SM = (2) N SM = 0.068(1) Determines also the N coefficient (electron polarization along neutron spin) to check polarimetry Already obsolete (additionally analyzed data will improve precision by a factor 2)

13 13MESON 2010, Cracow, June 10-16, 2010 O. Naviliat-Cuncic R in a GT : 8 Li at TRIUMF 8 Li source ~10 7 pps – 80% 30keV Implanted in annealed Pt at room temp.; B=500G Goal: improve by a factor 20 the best measurement so far in a GT transition [R. Huber et al., PRL 90 (2003) ] (reach the FSI level). Apparatus installed at TRIMF Test beam run planned in Nov.2010 (Rikkyo, KEK, TRIUMF), J.Murata & Co.

14 14MESON 2010, Cracow, June 10-16, 2010 O. Naviliat-Cuncic 3. Exotic couplings within the SM x : Fermi fraction;  : GT/F mixing ratio beyond the SM  contains quadratic S and T contributions  angular correlation (even under P and T transformations) …detect the recoiling ion to deduce neutrino momentum

15 15MESON 2010, Cracow, June 10-16, 2010 O. Naviliat-Cuncic a in GT : 6 He Paul GANIL RFQ cooler buncher First transparent prototype U RF ring hat “ideal” 3D Paul trapFully transparent trap (rings)

16 16MESON 2010, Cracow, June 10-16, 2010 O. Naviliat-Cuncic LPCTrap results (2008): collected 4×10 6 (for stat) and 2×10 6 (for sys studies) events. Statistical precision reached; data analysis under way. GOAL: Measure the  angular correlation in 6 He decay with (  a / a ) stat < 0.5% First data taking run in 2006 [X. Fléchard et al., PRL101 (2008) ] All position sensitive detectors; complete kinematics neutrino mass TOF

17 17MESON 2010, Cracow, June 10-16, 2010 O. Naviliat-Cuncic a in Fermi : WITCH Penning ISOLDE (K.U.Leuven, Uni. Munster, ISOLDE, GSI, NPI Rez-Prague) N.Severijns et al. First recoil ion spectrum Retardation potential (V) 124 Sn recoils Goal: measure  correlation in 35 Ar with (  a/a) stat  0.5 % Detect recoiling ions in singles Select ion energies sequentially: retardation potential [V.Yu. Kozlov et al., NIM B 266 (2008) 4515] Too low 35 Ar production/transport so far System being upgraded

18 18MESON 2010, Cracow, June 10-16, 2010 O. Naviliat-Cuncic Summary Precision measurements in nuclear beta decay have made significant progress over the past decade. (progress is slow) Dozens of new projects using radioactive nuclei, cold neutron beams and UCNs are under way (patience needed) New results are expected soon, in particular from experiments with atom and ion traps. Thanks to: K.Bodek, D.Melconian, J.Murata, N.Severijns, for inputs

19 19MESON 2010, Cracow, June 10-16, 2010 O. Naviliat-Cuncic Constraints on Scalar couplings [J.C. Hardy and I.S. Towner, PRC 79 (2009) ]

20 20MESON 2010, Cracow, June 10-16, 2010 O. Naviliat-Cuncic Constraints on Tensor couplings A in 114 In

21 21MESON 2010, Cracow, June 10-16, 2010 O. Naviliat-Cuncic Constraints on sums of exotic couplings


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