Beta Neutrino Correlation and T-Violation. Experiment in Nuclear Beta Decay Rikkyo Univ. Jiro Murata

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1 Beta Neutino Coelation and T-Violation Expeiment in Nuclea Beta Decay Rikkyo Univ. Jio Muata Beta Neutino Coelation using Recoil Measuement fom fee slow adioactive nuclei at RIKEN-RIBF RIBF (RIAB / SlowRI) Beta Tansvese Polaization Measuement fom stopped polaized adioactive nuclei at KEK-TRIAC / RIKEN-RIBF RIBF Collaboation Rikkyo Univ. / RIKEN Asahi ANL / Titech Asahi Lab./KEK J. Muata, H. Kawamua, K. Naita, T. Suehio, T. Shimoyama,, T. Toyoda K. Asahi, D. Kameda, H. Ueno, A. Yoshimi M. Uchida, D. Nagae,, K. Shimada N. Imai, K. Hiayama 1

2 Unique Slow / Stopped RI Facilities at RIBF SLOWRI Facility fo Atomic Physics RIAB fo Magnetic Moment Study using Atomic Beam Method RI Beam Gas Catche + Gas Jet Poduction System Noble Gas Stoppe Supesonic Gas Jet Cold RI Atomic Beam ~ 400 m/sec Wada (RIKEN) et. al. Beta Decay in Vacuum RI Beam ~ 100MeV/u NO EM Field Yoshimi (RIKEN), this conf. Recoil Measuement 2

3 Expeimental Setup fo Beta Neutino Coelation measuement w/o using Ion Taps Electon Tacking Chambe Electon Momentum Measuement + Vetex Detemination Recoil Ion Detecto Static Electic Field Acceleation 2d Position Sensitive MCP R&D of Slow RI Poduction 2008 ~??? 3

4 Beta Decay de dω dω dω = 1 2 p E ( E0 E ) 5 ( 2π ) Measuement using Slow RI p p 1+ a E E + σ p G E m p p p p + b + J + + I A B D E E E E E p p p p p p + H + K + L E E + m E E E E + NJ I p + Q J E + m I p E + RJ I p E Recoil Measuement a p E p E Pecoilecoil Test of V-A V A inteaction a=1 (Femi), -1/3 (GT)? Scale / Tenso Int. exists? Pbetabeta Pneutino Angula Distibution pecision ~ 10 ^ -3 Cs/Cv Cv <8% (Femi) CT/C /CA <13% (GT) Electon Measuement p RJ JE σ Pecoilecoil T-Violating TRANSVERSE polaization R=0 o NOT? PSI 03 8Li exp. PSI 05 muon exp. ( 0. 9 ± 2. 2) 10 Pbetabeta Tansvese Polaization 3 M LQ > 2 560GeV/ c 3 ( 3. 7 ± 7. 7 ± 3. 4) 10 PSI 4 PSI ntrv exp.?

5 Stopped RI Facility at KEK-TRIAC Unpol 8Li Beam (178keV/u) ~ % polaization up to 10%? 2005 Hiayama et. al. (KEK) Tilted Foil : 10ug/cm^2 Cabon x 70deg. 5 Polaized Low Enegy 8Li beam is available!

6 R-Coelation Measuement Tansvese pol.. of electon fom pol.. Nuclei Mott Scatteing RJ p σ Pol. Exists Systematic Eo ~ 10mg/cm2 ( ~micon) ~ 50% max. max. at 110deg. Backwad scatt. ~ 10^-3 3 ~ -4 6

7 Expeimental Setup fo R-MeasuementR Polaized RI in Solid Stoppe like beta-nmr Dift Chambe : as Polaimete Pojectile RIPS Tilted TRIAC, KEK-JAERI Angula Resolution < 1 deg. Full Backwad Solid Angle Maximum Mott Sensitivity 7

8 Advantages of the New Points Counte Foil Activation U/D atio Foil Slits Off Foil Scatt. Fake Events A(q) ) Changing U/D Acceptance Changing Tacking No Slits Tacking Lage Acceptance Select Scatteing Events Independent on Decay Asymmety Changing Scatt.. Angle Measuement Foil 8

9 Backgound Rate in Counte Expeiment Test RIKEN-RIPS RIPS Beam Line Polaized Seconday Beam : 31Al 95MeV/u Foil ON/OFF ON Qbeta- = 8.0MeV No Accidental stoppe electon stat stop 9um Gold Foil veto OFF TDC (stat stop) Signal / Backgound ~ 10% Tacking Device -> > Reject Ghost Events 9

10 DC Polaimete XX UU VV Plane DC 104 Anode Sense 20um Au-W 50g x 104 Field 100um 150g x 110 Cathode 100um 150g x 413 Total 627 Wies Sense - Field Pitch = 10mm Sense - Cathode Gap = 10mm XX (1/2cell off) x 40 UU (15.9deg.) x 32 VV (-15.9deg.) x 32 Cathode(90deg.) Point Souce Tacks ~ 200 um es. 64ch ASD peamp x 2 + VME AMU-TDC x 2 10

11 Tack Reconstuction fo Scatteed Events Lead Foil DC Souce stat 90S/Y beta souce (Qb( Qb=2.283MeV) Reconstucted V-Tacks V (eal data) 11

12 Configuation Dependence on Acceptance Pesent Design Plastic Polaimete PSI 8Li Exp. type 10MeV 0.9uA 7Li(d,p)8Li 99.9% 7Li taget, GBq B = 7mT, Pol = Relaxation time > 20sec Lead foil analyze 35mg/cm2 Dift Chambe Polaimete : Limited Solid Angle, not suitable fo High Rate GOAL : Cylindical MWPC Polaimete : Lage Solid Angle, good fo High Rate 12

13 Monte-Calo Estimation of the Acceptance Dift Chambe Polaimete Plastic Polaimete Ove 90deg ~ 10micon Gold Foil on foil 0.84% Aound peak FOM 9.6% Total Abs. Acc. 7.5 x 10^-5 (75cps fom 1MBq) 13

14 Expected Sensitivity asymmety angle (deg.) Fitting Simulated Asymmety PSI 03: 700MBq, pol 10% TRIAC: 1-10MBq. 1 10MBq. pol 10% RIBF : 1-10GBq. pol??? 14

15 Final State Inteaction Rξ = M + δ J ' J M F GT M 2 λ GT J ' J ± 2Im J J αzm ( C C ' + C ' C ) 2Re( C C ' C ' C ) T 2 Im + αzm 1 m p A T ( C + ) ( ) SCA' CS ' CA CV CT ' CV ' CT 2Re CSCT ' + CS ' CT CV CA' CV ' CA e Expeimental Sensitivity eaching Electomagnetic Final State Inteaction Possible way is.. A p e T T A A Contibution fom pue V-AV R = (0.9 ± R FSI 2.2) 10 = FSI is BG, fo T-Violation T Physics AND/OR 2. Study of FSI Physics Systematic Evaluation of the FSI 1. Nuclea dep. 2. Beta enegy dep. Extact Tue T-ViolationT Suitable fo RI Beam Factoy Heavy Isotope Measuement Nuclea Size, Stuctue effect, etc. FSI αzm p 15

16 Summay Status 1. Dift Chambe Polaimete has been built. 2. Polaized 8Li is now available at TRIAC. 3. Study of physics sensitivity is completed. 4. Stoppe R&D is undegoing. 5. Fist test expeiment using DC- polaimete & polaized beam will be pefomed in ealy 2007 Plan 1. Pefom 1 st step expeiment at TRIAC. 2. Upgade. Beam Intensity: 10^5 to 10^7 design value Polaization: 5% to 10% using tilted foil 10% to 20% o moe using optical pumping? 3. Utilize 10^10 RIBF Optical Pumping in Solid Cylindical Popotional Counte Polaimete 16