Tau Physics Flavor Physics and CP Violation May

Tau Physics Flavor Physics and CP Violation May 5 -9, 2008, National Taiwan University, Taiwan Hisaki Hayashii Nara Women’s University May 5 -9, 2008 National Taiwan University, Taipei, Taiwan 1

Contents Lepton Flavor Violation in t decays Tau decays to strange particles 2 p decay and muon anomalous magnetic moment May 5 -9, 2008 National Taiwan University, Taipei, Taiwan 2

Lepton Flavor Violation (LFV) Standard Model (SM) exactly forbids LFV. Extended SM including neutrino mixing term includes LFV. l Charged Lepton Flavor Violation can occur through loop diagram. But, extremely tiny branching ratio below experimental sensitivity l (Marciano and Sanda, Phys. Lett. B 67 (1977), Pham, EPJ C 8(1999)513) Many NP models include LFV vertex naturally. Observation of charged LFV l Clear signal of new physics! Tau lepton has many possible LFV decay modes. l Wide window to probe New Physics May 5 -9, 2008 National Taiwan University, Taipei, Taiwan effects. 3

LFV tau decays Predicted by many new physics models l Normal NP models enhance t mg. l For some NP parameters, other modes may be enhanced instead. Reference t mg t mmm SM+ n mixing EPJ C 8(1999)513 10 -49 -52 10 -14 SM + heavy Maj n. R PRD 66(2002)034008 10 -9 10 -10 Non-universal Z’ PLB 547(2002)252 10 -9 10 -8 SUSY SO(10) PRD 68(2003)033012 10 -8 10 -10 m. SUGRA+seesaw PRD 66(2002)115013 10 -7 10 -9 SUSY Higgs PLB 566(2003)517 10 -10 10 -7 May 5 -9, 2008 National Taiwan University, Taipei, Taiwan 4

Status of LFV search at spring 2007 Belle Ba. Bar UL 90 (10 -7) Lum (fb-1) mg 0. 5 535 0. 7 232 eg 1. 2 535 1. 1 mh 0. 7 401 mh’ 1. 3 mp 0 Belle Ba. Bar UL 90 (10 -7) Lum (fb-1) ep 0 0. 8 401 1. 3 339 232 3 l 2 -4 87 1 -3 92 1. 5 339 lhh 2 -16 158 1 -5 221 401 1. 3 339 m. V 0 2. 8 -7. 7 158 1. 2 401 1. 5 339 e. V 0 3. 0 -7. 3 158 eh 0. 9 401 1. 6 339 m. Ks 0. 5 281 eh’ 1. 6 401 2. 4 339 e. Ks 0. 6 281 Current accumulated luminosity; >700 fb-1 at Belle and >500 fb-1 at Ba. Bar. Searches for 3 l, lhh modes should be updated. May 5 -9, 2008 National Taiwan University, Taipei, Taiwan V 0=r, w, f, K* 5

LFV analysis Signal extraction l Calc. Minv and DE DE=Erec-Ebeam l Blinded signal region l Event selection study l Estimate background using sideband data l Open blind and estimate signal yield l Estimate upper limits by Likelihood fit or number of events in signal region l Signal region Signal MC BG reduction is important to improve the sensitivity. l Find effective ways to use all information May 5 -9, 2008 National Taiwan University, Taipei, Taiwan Background 6 Minv

t 3 leptons; BG reduction BG events Bhabha(mm) eemm(eeee) Signal topology - g conversion veto (e-e+e- and m-e+e-) - Electron-veto on the tag-side (e-e+e- and e-m+m-) Optimized event selection for each mode separately because the BG processes are different. May 5 -9, 2008 National Taiwan University, Taipei, Taiwan 7

t lll search; Belle data Data; 535 fb-1 Efficiency; (6. 0 -12. 5)% NBG; 0. 0 -0. 4 events Nobs; 0 events for all modes Br<(2. 0 -4. 1)× 10 -8 at 90%C. L. signal t-ge-e+e- signal region (Y. Miyazaki et. al. , PLB 660 (2008) 154) t-gm-m+m- May 5 -9, 2008 National Taiwan University, Taipei, Taiwan 8

t lll search; Ba. Bar Data; 376 fb-1 Efficiency; (5. 5 -12. 4)% NBG; 0. 3 -1. 3 events l Total BG; 4. 2± 0. 8 Nobs; 6 events in total Br<(3. 7 -8. 0)× 10 -8 at 90%C. L. (B. Aubert et. al. , PRL 99 (2007) 251803) May 5 -9, 2008 National Taiwan University, Taipei, Taiwan =Minv-Mt 9

t l. V 0 search data signal Belle; 543 fb-1 data Ten modes are investigated, l=e, m and V 0=r, K*0, f, w Main BG: SM t decay; t pwn, t pppn Signal Efficiency; 2. 5 - 4. 9 % Expected NBG; 0. 0 - 1. 0 events Observed number of events; 1 event for t mf, ew, e. K*0 0 events for others Br<(5. 9 -18)× 10 -8 (Y. Nishio et. al. , ar. Xiv: 0801. 2475) Ba. Bar; 384 fb-1 data l Searched for mw, ew Br<(10 -11)× 10 -8 (B. Aubert et. al. , PRL 100; 071802 2008) May 5 -9, 2008 National Taiwan University, Taipei, Taiwan 10

t lf 0(980) search ● data signal MC mf 0 Br(t→mf 0): Br(t→mmm): Br (t→mh) = 1. 3 : 0. 54 : 1 (C. H. Chen et. al, PRD 74: 035010, 2006 ) Scalar Higgs mediation l No search yet. Belle; 671 fb-1 l Use f 0(980) p+p- (4 s) m f 0(980) e f 0(980) m efficiency 6. 0% 5. 8% NBG 0. 11± 0. 08 0. 10± 0. 07 No event is observed. Preliminary result Br(t→l f 0(980) )x. Br(f 0(980)→p+p-) f 0(980) : <3. 3 X 10 -8, e f 0(980) : May 5 -9, 2008 ef 0 <3. 4 X 10 -8 National Taiwan University, Taipei, Taiwan 11

Current status of LFV search Belle Ba. Bar UL 90 (10 -7) Lum (fb-1) mg 0. 5 535 0. 7 232 eg 1. 2 535 1. 1 mh 0. 7 401 mh’ 1. 3 401 mp 0 1. 2 401 Belle Ba. Bar UL 90 (10 -7) Lum (fb-1) ep 0 0. 8 401 1. 3 339 232 3 l 2 -4 0. 2 -0. 4 87 535 1 -3 0. 4 -0. 8 92 376 1. 5 339 lhh 2 -16 158 1 -5 221 1. 3 339 m. V 0 2. 8 -7. 7 0. 6 -1. 3 158 543 1. 0(mw) 384 3. 0 -7. 3 0. 6 -1. 8 158 543 1. 1(ew) 384 1. 5 339 e. V 0 eh 0. 9 401 1. 6 339 mf 0 0. 33 671 eh’ 1. 6 401 2. 4 339 ef 0 0. 34 671 V 0=r, w, f, K* Sensitivity is improved by factors of 3 -10. It comes from the luminosity increase and successful BG reduction. t 3 leptons sets most stringent upper limit. May 5 -9, 2008 National Taiwan University, Taipei, Taiwan 12

LFV Searches Prospects B-factories improved LFV tau Br limit by factor 10 -100 Limits can be improved by factor 2 -4 analyzing all planned B-factories yield. Super B-factories expected to improve search region again by factor 10 -100 dep. on bkg. l t lg; scale as ~1/ L e+e- t+t-g is irreducible BG. l ~10 -8 level at super B-factory l t lll, l. X 0; scale as ~1/L l BG can be reduced by lepton-ID or mass requirement for X 0 l O(10 -9) level at super B-factory l May 5 -9, 2008 National Taiwan University, Taipei, Taiwan 13

Tau decays to strange particles B-factory detectors have a good p/K separation, useful to discriminate Cabibbo-suppressed t s decays Inclusive t s can potentially achieve most precise/clean Vus measurement (0. 7%): by Pich l In t s decays the uncertainty on Vus is dominated by experimental uncertainties. l For 3 -body K decays, the uncertainty on Vus is limited by theory determination of the form-factor : f(0)+ (1%->0. 5%? ). functions. National are. Taiwan also measured, Vus and ms can be May. If 5 -9, spectral 2008 University, Taipei, Taiwan 14 determined by a simultaneous fit.

Approaches to Vus Inclusive measurement by summing up all decay modes. May 5 -9, 2008 National Taiwan University, Taipei, Taiwan 15

Before B factories: Br(t s ) Precision: May 5 -9, 2008 National Taiwan University, Taipei, Taiwan 4 -10% 16

Before B factories: Vus and ms Hadronic Width: Flavour SU(3) Breaking: where Vus Ｍａｌｔｍａｎ， ｈｅｐ-ph/061１ 1８０ May 5 -9, 2008 National Taiwan University, Taipei, Taiwan 17 Ms (Ge. V)

Strength at B-factories Good K-p Separation High Statistics Well separated in space May 5 -9, 2008 National Taiwan University, Taipei, Taiwan 18

Br(t- Kpnt) t- K-p 0 nt ü 230 fb-1 data ü 78 K e/m tagged events PRD 76 (2007) 051104(R) t- Ksp-nt ü 351 fb-1 data ü 53 K e/m tagged events PL B 654 (2007) 65 May 5 -9, 2008 National Taiwan University, Taipei, Taiwan 19

Exclusive Br(t- h-h+h-nt) PRL 100 (2008) 011801 May 5 -9, 2008 National Taiwan University, Taipei, Taiwan 20

Update on Vus using B Factor Results [1] By Pich [2] Updated Results [2] Babar: lt- K-p 0 nt 3. 3 s hep-ex/0707. 3058 PRD 76 (2007) 051104(R) lt- K-p+p-nt PRL 100 (2008) 011801 Belle: lt - [1] M. Palutan, Kaon’ 07 [2] M. Jamin, Moriond EW ‘ 07 S. Banerjee, ar. Xiv: 0707. 3054 v 4 May 5 -9, 2008 K sp - n t PLB 654 (2007) 65 Theory prediction assuming m-t universality - K -n ) l Br(t t National Taiwan University, Taipei, Taiwan from Br(K- m-21 nt )

t- p-p 0 nt and am t- p-p 0 nt l has the largest Br l CVC relation with e+e-→p+ pl Plays an important role for the h. v. p. term in the muon anomalous magnetic moment. am=(gm-2)/2 +CVC hadron May 5 -9, 2008 National Taiwan University, Taipei, Taiwan 22

Status of am Recent data indicate that there is a systematic difference between the 2 p system in e+e－ reaction and t-decays, even after applying known isospin violation correction. Main difference btw and is from 2 p mode. ICHEP-2006(M. Davier et al. ): am(exp)-am(th) is not yet published preliminary A hint to New Physics beyond the SM!? May 5 -9, 2008 National Taiwan University, Taipei, Taiwan How about t ? 23

Pion Form Factor |Fπ|2 From 23 M t+t- pairs, Belle selects 5. 4 M t- Fp p-p 0 nt events! 2 | F π | 2 n. Unfolded by Singular Value Decomposition Method. Error bars include both statistical and systematic Fit with BW May 5 -9, 2008 Nationalr”: Taiwan University, Taiwan Interference between r’ and r” Taipei, signal significance 6. 5 s 24

Br(t- p-p 0 nt ) Normalized to the number of t-pairs Belle 25. 12 0. 04 0. 38 Tau-pair selection acceptance : 32. 6 0. 05% : 1. 112 0. 003 background : 7. 4 0. 03% pp 0 selection Acceptance: 41. 0 0. 1 % Background feed down: 7. 02 0. 08 % qq-conti. : 2. 22 0. 05 % Br= (25. 12 0. 04（stat) 0. 38(sys))% Preliminary May 5 -9, 2008 National Taiwan University, Taipei, Taiwan 25

Systematic on Br Measurement Source Tracking efficiency p 0 efficiency Background in t-pair Feed down background Continuum background g veto Trigger MC statistics Total Systematic is dominated by the uncertainty of l l l 0. 47 1. 4 0. 36 0. 16 0. 20 0. 32 0. 08 1. 6 the p 0 efficiency Calibrated by h signals ( ). Checked by using electron tracks. (gg →p 0 p 0 can use to improve p 0 efficiency in near future. ) May 5 -9, 2008 National Taiwan University, Taipei, Taiwan 26

Systematic on the Mass Spectrum/Form Factor M 2 pp threshold r region r’ region r” region ( %) Unfolding (MC) 0. 79 0. 31 1. 50 Unfolding (cond) 0. 53 0. 09 0. 58 9. 19 BKG (continuum) 0. 09 0. 01 0. 52 5. 76 BKG (feed-down ) 0. 65 0. 10 --- 0. 50 BKG(non-p 0) 4. 80 --- --- Acceptance 1. 44 0. 03 0. 15 0. 40 Energy scale 1. 08 0. 59 0. 05 0. 50 Total 5. 3 0. 7 1. 8 11. 4 Systematic 0. 7 -1. 8% 5% May 5 -9, 2008 10% Region Dominant Factor r, r’ Energy scale/Unfolding threshold Background (p 0, feed down) National Taiwan University, Taipei, Taiwan r’’ Continuum BG/Unfolding Check by known MC distribution 27

Comparison with previous exp. Fit: Fit to Belle Data Belle-CLEO consistent, ALEPH is higher at (Mpp)2 > 0. 8 Ge. V 2 May 5 -9, 2008 Effect on am 2 p ? i National Taiwan University, Taipei, Taiwan 28

Results range (Ge. V 2) am （２ p） Belle ALEPH 0. 08 -0. 20 39. 57 38. 23 0. 20 -0. 35 70. 65 66. 89 0. 35 -0. 50 123. 30 119. 20 0. 50 -0. 65 196. 90 194. 20 0. 65 -0. 80 62. 37 62. 39 0. 80 -0. 95 15. 64 16. 41 0. 95 -1. 10 5. 74 6. 50 1. 10 -1. 25 2. 86 3. 27 1. 25 -1. 40 1. 65 1. 89 1. 40 -3. 20 May 5 -9, 2008 2. 43 0. 08 -3. 20 521. 1 X 10 -10 Belle> ALEPH Belle<ALEPH No iso-spin violation correction is applied 2. 77 National Taiwan University, Taipei, Taiwan 511. 5 29 Total

Isospin Violation Correction Ref. V. Cirigliano et al. , J. High Energy Phys. 08, 002(2002) A. Flores-Tlalpa et al. , Phys. Rev. D 74, 071301 (2006) Source Correction Short distance rad. Cor (SEW) Long distance rad. Cor. (GEM) mpmp 0 (in phase space) r-w interference mpmp 0 (in decay width) Electromagnetic decays mr 0 mr – -12. 0 -1. 0 -7. 0 +3. 5 +4. 2 -1. 4 - Total -13. 7 May 5 -9, 2008 X 10 -10 Uncertainty National Taiwan University, Taipei, Taiwan 0. 2 0. 6 1. 4 2. 0 30

am （２ p）: comparison t and e+e. Integrated region: After applying the known iso-spin violation correction. Belle(t) ALEPH, CLEO, OPAL (t) CMD 2, SND (e+e-) Ref. Eur. Phys. J. C 27, 497 (2003) Ref. Nucl. Phys. Proc. Suppl. 169, 288 (2007) t results are higher than those from e+ e-. May 5 -9, 2008 National Taiwan University, Taipei, Taiwan 31

Conclusions/Summary LFV Searches l Good experimental coverage l New searches for 3 -prong final state t 3 l, l. V 0, lf 0 using 400~700 fb-1 of data l Better sensitivity than previous analysis l LFV sensitivities are Br~O(10 -8) Ø LFV are Super B-factory Golden channels Sensitivity will reach Br~O(10 -9). Vus from t s inclusive l Results on several Br, Vus are updated. l 3. 3 s discrepancy w. r. t Kaons and unitarity l l Spectrum measurement: cross check + determine Vus and ms, simultaneously. High statistics study on t- p-p 0 nt l Br and mass spectrum are updated. l In addition to r(700), r’(1400), the production of r’’(1700) is unambiguously identified and its parameters are determined. l Belle results for agree with the previous t based results but are May 5 -9, 2008 National+ 32 higher than those from e Taiwan e-. University, Taipei, Taiwan

r-w-f int. based on the Hidden Local Symmetry can explain the difference of 2 p spec. between e+e- and t (M. Benayoun et al. arxiv: 0711. 4482) May 5 -9, 2008 National Taiwan University, Taipei, Taiwan 33

Backup Slide May 5 -9, 2008 National Taiwan University, Taipei, Taiwan 34

External parameters Item Value 1. 0233± 0. 0006 ± 0. 32 0. 9734± 0. 0008 ± 0. 42 (17. 84± 0. 06)% ± 1. 82 (25. 42± 0. 11)% ± 2. 30 ±３．０ Total World average is calculated combining our new result and the preceding measurements of other experiments. May 5 -9, 2008 National Taiwan University, Taipei, Taiwan 35

Davier et al. Mod. Phys. 78, 1043 (2007) May 5 -9, 2008 National Taiwan University, Taipei, Taiwan 36

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