1 / 21

Study of b - n correlations with LPCTrap

Laboratoire de Physique Corpusculaire - Caen. Study of b - n correlations with LPCTrap. Dominique Durand LPC Caen, ENSICAEN, Université de Caen, CNRS/IN2P3, Caen, France On behalf of the LPCTrap collaboration. EXON 2012. Outline. Motivation Physics case and m easurement principle

cooper
Download Presentation

Study of b - n correlations with LPCTrap

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. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Laboratoire de Physique Corpusculaire - Caen Study of b-ncorrelations with LPCTrap Dominique Durand LPC Caen, ENSICAEN, Université de Caen, CNRS/IN2P3, Caen, France On behalf of the LPCTrap collaboration

  2. EXON 2012 Outline • Motivation • Physics case and measurement principle • Experiments and results • Summary

  3. STANDARD MODEL of Particle Physics is a very powerful and predictive model (recent Higgs probable discovery) but it is probably not complete • Questions: nmass hierarchy, strong CP problem, matter/anti-matter, dark energy/matter • Test at low energy: • high precision measurements • search for very small deviations from SM predictions • EDM’s, correlations (A, a, b, B, D, R, ….), g-2… • search for very rare (presumably forbidden) processes • neutrinoless double bdecay, proton decay, … • High precision and high energy experiments are complementary

  4. bdecay and the weak interaction 2+ Measurement of the beta neutrino angular correlation parameter abn + • observables linked to  are sensitive to abn • Recoil Ion (RI) momentum spectrum b- b decay rate: E: energy and velocity of the beta particle Wo(E): phase space distribution as given by the Fermi theory of beta decay : angle between the antineutrino and beta particle

  5. bdecay, Vector -Axial, abn • SM Test  pure vector axial interaction theory study through b decay • abn is a function of the coupling constants • Gamow-Teller  Axial / Tensor • Fermi  Vector / Scalar CL : 95.5% • Exotic currents (beyond SM) tensor/scalar abn(CV, CS, CA, CT, MF, MGT) : b-nangularcorrelationparameter Pure F : aF (CV, CS) = +1 (SM, CS = 0) Pure GT : aGT (CA, CT) = -1/3 (SM, CT = 0) Goal: new physics or Improve constraints on couplings - angular correlation coefficient measurement a with relative statistical uncertainty less than 0.5% deviation from abn=-1/3 or 1 (SM) might reveal existence ofnew particles: leptoquark bosons …

  6. CKM matrix and abn For mirror transitions : r=GT/F & abn(r) = (1-r ²/3)/(1+r ²) Proceedings of CKM2010, the 6th International Workshop on the CKM Unitarity Triangle. T Sparado , A. Young • Mirror transitions : • Analysis of available data (5 nuclei) • competitivewithneutron/pion decay • Valuablealternative to 0+->0+ transitions • Several parameters to be measured: T1/2, BR, Q, r • and to be computed (corrections) O. NaviliatCuncic et al., PRL102 (2009)

  7. How to measure abn • observables linked to  are sensitive to abn • Recoil Ion (RI) momentum spectrum • Ion trapping techniques are universal (several nuclei) • - LPCTrap:abndeduced from RI ToF measurement • - ions almost at rest and well localized • - open configuration, few dead zones • Precision measurement Dabn/ abn <1%: • very difficult experiment: • systematic effects such as the • RF field  ToF spectrum deformation • «shake-off»ionization probability required Transparent Paul Trap

  8. Nuclei of interest V-A 6He+ pure GT transition, tensorcoupling abn=-1/3 High Q value, RI (6Li) up to 1.4 keV T1/2 high rate and efficient transmission to the trap Vud and V-A 35Ar+, Mirror 35Cln+ scalarcoupling, mixed transition corrections abn=0.904 High Q value but heavier ion RI (35Cl) up to 450 eV T1/2 high rate and efficient transmission to the trap Other candidates: 19Ne, 37K, 39Ca

  9. LIRAT LIRAT Production target ECR source LPCtrap@GANIL/SPIRAL1 • Beam characteristics : • 10-30 keV, 80 p mm mrad • rate : ~ 108 ions/s LPCTrap Paul trap Effective potential 1-2 V Beam-handling SPIRAL 6He beam 10 keV DE ~ 20eV

  10. Beam line preparation 1meter Beam6He+ • RFQCB: • High-voltage platform • Buffer-gas cooling technique: H2 or He • Ion bunches • Continuous voltage: longitudinal confinement • RF field: radial confinement • Cycle period: 200ms (accumulation) ~5 1046He+/s trapped ions • Total efficiency: ~2.5 10-4 ~2 1086He+/s • Ions bunches • Cycle period: 200ms • (accumulation)

  11. Detectors and trap 6He+ bunch MCP with delay line anode • Beta position • Eβ • MCP •  telescope Ion trap Recoils b- Time of flight: Free flight tube Charge state separation: Free flight tube MCPPSD Post-acceleration Silicon + plastic scintillator + PMT • Detection in coincidenceof recoil ion (RI) and b particle • ToF measurement (b detection: START, RI detection: STOP) • Post-acceleration between the two collimators (Installed 2009) • 50 cm free flight tube  charge state separation(identified by ToF)

  12. Recoil ion detector design Focusing electrode Collimator Grounded collimator • Acceleration electrode Grid MCPPSD • Focusing electrode to collect recoil ions with maximal efficiency • Geometry design and bias voltages estimation with “SIMION” software • Successfully tested during four days in November 2010 LPCTrap : simultaneous measurement of abnand the «shake-off»probability

  13. 6He+ :experimental results (2006-2010) 1963 Vise (coincidence) 1963 Pshake-off = 0.02339(35)stat(07)syst PRL (Couratin et al.) 108 (2012) 243201 2010 Result: abn= - 0.3335(73)stat(75)syst SM value = -1/3 PRL (Fléchard et al.) 38 (2011) 055101 6He+ Pure GT Limit on Tensor 105 events • ( Dabn/abn ) stat~2% Improvestatisticsalsoimprovesystematicuncertainties - effect of ion cloudtemperature - effect of b back-scattering

  14. 6He+ : experimental results (2006-2010), shake off Experiment: ~4 days,Intensity ~108 pps, ~1.2 106 «true» coincidences • Complete Monte-Carlo simulation w/all systematic effects: RF fields, ion cloud characteristics, detectors response functions... • Experimental spectrum fit w/ Pshake-off as free parameter assuming abn = -1/3 Li2+ Li3+ Pshake-off = 0.02339(35)stat(07)syst PRL (Couratin et al.) 108 (2012) 243201 “exceptional research” from APS • High precision: DPshake-off=3.6 10-4 • Excellent agreement: theoretical value • of 0.0233 Data analysis still in progress GOAL: abn estimation Preliminary: agreement w/ SM value Relative stat. uncertainty < 0.5%

  15. 35Ar+ : experiments results (2011-2012) 35Cl charge state distribution 3 - 4 10735Ar+/s incoming beam with ~2.5 x 108contaminants/s 2 - 3 x 104 trapped 35Ar+ ions (every 200 ms) • 2011commissioningrun 2 days • 2012 8 daysrun @GANIL/LIRAT • expected final uncertainty Dabn(stat) < 0.002 • full analysis is underway

  16. PREMS: re-submitted to the ANR Implantation tape station Multi Reflection Time Of Flight Mass Spectrometer (MR-TOF-MS needed for new beams) Small RFQ ("rebuncher") Main RFQ taccu ~ 1-10ms taccu ~ 100ms New chamber At least a factor ~ 10 in statistics

  17. Summary & future plans • Precision measurement of the b-decay of exotic nuclei can probe • the weak interaction part of the Standard Model: abn V-A, Vud • LPCTrap is a universal tool that measures accurately abnfor • several nuclei of interest and provide shake-off probabilities • Near future: Ne19 experiment accepted by GANIL PAC • Future: new beams and new apparatus • - PREMS: renewal of the experimental set-up on the LIRAT beam line • - new exotic beams and facilities are needed  S3/DESIR@SPIRAL2

  18. LPC CAEN : Claire Couratin (PhD-2013) Dominique Durand Xavier Fabian (PhD-2015) Xavier Fléchard Etienne Liénard François Mauger Oscar Naviliat-Cuncic Gilles Quéméner Philippe Velten (PhD-2011) GANIL:Pierre Delahaye Bertrand Jacquot Jean-Charles Thomas CIMAP:Alain Méry KUL Leuven: Martin Breitenfeldt Simon Van Gorp TomikaPorobic NathalSeverijns and the LPC technicalstaff alsothanks to the GANIL beamoperators

  19. EXON 2012 WITCH ISOLDE CERN Measureabnwith a precisionbetter than 0,5 % ISOLDE+ REXTRAP (beam handling) Penningtraps Retardation spectrometer Main isotope 35 Ar + Scalarsearches

  20. EXON 2012 WITCH ISOLDE CERN • After solving all kind of problems • Local penning, mechanical… • Data Obtained in 2011 with 35Ar • abn= 1.12 (33)stat • SM value of a =0.9004(16). • Still a lot to measure and simulate • Next run Oct 2012

  21. EXON 2012 We are not alone… From N. Severjins, KUL

More Related