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T.Ohshima Beijing 2004 / LFV at B-Factories1 Lepton Flavor Violation Search at B Factories T. Ohshima (Nagoya U.) ’s LFV and New Physics ’s at B-Factory New Data from B-Factory / e , ( /e) + ( 0 / / ’), 3 leptons, p / p 0, , and Ks / eKs Summary
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T.Ohshima Beijing 2004 / LFV at B-Factories2 CLEO made extensive study on ’s LFV with about 10/fb(10M ’s). Sensitivities on Br O(10 -6 ) Now, B-factory gets about 300 M ’s with luminosity 10 34 /cm 2 s ever achieved. If no-BG w/ 10%, Br O(10 -8 ) Tau at B-Factory ( Belle & BaBar )
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T.Ohshima Beijing 2004 / LFV at B-Factories3 Experiment : (e + e - ) = 0.9 nb; (e + e - BB) = 1.0 nb at (4S) (1) Properties : produced in pair; >0 ’s; ISR(initial rad.) (2) Sensitivity : For BG 0, sensitivity cannot be improved linearly with 1/ L 1/ L (3) Method for detection : BG Suppression Tau at B-Factory ( Belle & BaBar ) 1.look for decays in exclusive mode ( low multiplicity ) 2.Separation into 2-hemisphers signal-side: 1 or 3 prong ( l , l 0, l , p , p 0 / l / ’, 3 l, ) tag-side: 1-prong (Br = 80%) 3.BG (higher-order radiative Bhabha and , qq, with wrong PID) 4.Sample selection 5.Signal should have M inv =M and E=0 (E signal CM -E beam CM ) 6.Blind analysis over signal-region 7.Expect BG evaluation in signal-region 8.Blind opened and candidates obserced 9.Calculation of an upper limit by Bayesian/ Feldman-Cousins or Maximum likelihood method
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T.Ohshima Beijing 2004 / LFV at B-Factories4 New Data from Belle & BaBar 1. & e Data history Normal ordering case for tan >1 Br tan 2 / M SUSY 4 Br( ee) / Br( ) 1/94 Br( )/ Br( ) 1/440 Br( eee) / Br( e ) 1/94 Br( e )/ Br( e ) 1/440 MSSM +Seesaw ee J.Ellis, J.Hisano, M.Raidal and Y.Shimizu, PR D66 (2002) 115013 Br( ) (6x10 -7 ) ( ) 2 ( ) 4 tan 60 1 TeV M SUSY Photonic diagram
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T.Ohshima Beijing 2004 / LFV at B-Factories5 1 (1) Belle (86.3/fb) K. Abe et al, PRL 92 (2004) 171802-1 BG: & Selection on missing quantities p missing vs M 2 missing M inv - E 1-1 prong 98% of removed, 76% of signal survive.s Standard employed at Belle for most of analyses.
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T.Ohshima Beijing 2004 / LFV at B-Factories6 1 (1) Result E distribution Comparison with CLEO Bayesian method (s 0 w/ 90% CL) =10.8%, N =78.5x10 6 Br( ) < 3.4 x 10 -7 at 90% CL 3 region s=0; b=54; s0(90%CL)=5.1 ev
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T.Ohshima Beijing 2004 / LFV at B-Factories7 1 (2) e Belle (new data, 87.1/fb) K. Abe et al, Conf-contribution paper BG: & ee Selection on p missing vs m 2 missing M_inv- E E distribution Result Br( e ) < 3.8 x 10 -7 at 90% CL s = 3.75 ev (90%CL), b=20 ev = 6.5%, N =79.3x10 6 systematic uncertainty = 6.8% Preliminary
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T.Ohshima Beijing 2004 / LFV at B-Factories8 Br( ) (8x10 -7 ) ( ) 6 ( ) 4 2 ( /e)+( 0/ / ’), 3 l -> and sensitive to Higgs in SUSY Br( 3 l ) / Br( ) 0.2 Br( )/ Br( ) 0.006 Br( ’ )/ Br( ) 0.004 tan 60 100 GeV m A Br( ) : Br( 3 ) : Br( ) = Higgs mediated diagram K.S.Babu and C. Kolda, PRL 89 (2002) 241802 M. Sher, PR D66 (2002) 057301 A. Dedes, J. Ellis and M. Raidal, PL B549 (2002) 159. A. Brignole and A. Rossi, hep-ph/0404211. Enhancement of to 3 (1) a color factor 3, (2) Yukawa-coupling (m s /m ) 2, (3) Phase space 3/2. In total, a factor of 10 tan 2 mAmA 1 ( ) 4
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T.Ohshima Beijing 2004 / LFV at B-Factories9 2 (1) ( /e)+( 0 / / ’ ) Belle (new data,153.8/fb) K. Abe et al, Conf-contribution paper 432 BG: & qq Selection on p missing vs m 2 missing Signal MC and masses for tag side, m tag < 1.777 GeV/c 2 E-Minv 0.0 +0.4 / 0 ev 0.23 0.23 / 0 ev0.15 0.15 / 0 ev0.16 0.16 / 1 ev 2.7 0.7 / 5 ev0.6 0.4 / 0 ev3.1 .0 / 1 ev 1.4 0.6 / 0 ev expected BG / obserbed ev 90% aperturedata -0.0
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T.Ohshima Beijing 2004 / LFV at B-Factories10 List of results First measurements of e ’ and ’ Systematics Preliminary 2 (1) ( /e)+( 0 / / ’ )
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T.Ohshima Beijing 2004 / LFV at B-Factories11 2 (2) 3 l (e - e + e -,e - + -,e + - -, - e - e +, + e - e -, - + - ) Babar Collaboration: B. Aubert et al. PRL 92(2004) 121801 Belle Collaboration: K. Abe et al. PL B589(2004) 103. Babar (91.5/fb) ; Belle (80/fb) BG: & qq lepton identification BaBarBelle Since the signal-region is not dominated by BG yet, sensitivity will be improved still proportional to accumulated luminosity. Therefore, in this year or next year, the sensitivity of 10-8 will be realized.
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T.Ohshima Beijing 2004 / LFV at B-Factories12 3 (1) p p Result For p (154/fb) s ( @90%CL ) = 10.6 ev w/ sys. (s=3.1, b=66.9 ev) =5.8%, N =140x10 6 pp Belle (new data, 154/fb) K. Abe et al, Conf-contribution paper 433 BG: & qq Selection on p missing vs m 2 missing Proton identification Preliminary For p (87/fb) s ( @90%CL ) = 4.5 ev w/ sys. (s=0.16, b=15.9) =9.4%, N =79x10 6 M_inv- E
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T.Ohshima Beijing 2004 / LFV at B-Factories13 3 (2) Belle (new data, 154/fb) K. Abe et al, Conf-contribution paper 433 BG : & qq Selection on p missing vs m 2 missing L-B conserving (p ) & violating (p ) E vs M inv Result Preliminary
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T.Ohshima Beijing 2004 / LFV at B-Factories14 Sensitivities are improved by a factor of ten or more compared to previous ones, based on at most a quarter of billions of tau events or less. Now, B factories give us sensitivity that, for the first time, enable us to seek for new physics in Lepton Flavor Violation in tau-decay. Summary Red: preliminary but contributed to this Conf. Blue: preliminary but reported in elsewhere. Black: published.
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T.Ohshima Beijing 2004 / LFV at B-Factories15 Research results on some physics parameters: m A vs tan plot from M SUSY vs tan plot from m STAU vs Br from e ee Belle and BaBar have now about a half of billions of tau events, 300/fb. Sensitivity on LFV gets soon to be 10 -8 level, and research region for new physics is getting expand. We can expect some interesting results.
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