1. t Results from Belle For the Belle collaboration Hisaki Hayashii
Nara, Japan
BES-Belle-CLEO-Babar
2007 Joint Workshop
IHEP, Beijing, Nov. 2007
I’d like to present the recent results on tau physics from B factory experiments.

2. t- t hadronic decays nt Lepton Flavor Violating rare decaysW-
u-bar
d/s
t hadronic decays
Ideal place to study low mass
hadronic system
as, am, ms, Vus, vacuum condensate
QCD, Lattice and String Theory
No final state interaction
Non-strange and strange final states.
Possible Jp
Vector (1-, 1+) and Scalar (0-, 0+)
Only pn, Kn decays are scalar states observed so far.
Lepton Flavor Violating rare decays
（One of the most） promising processes to look for beyond SM
Nov. 27, 2007
BBCB Workshop

3. Outline　
A few selected topics on t-physics from Belle experiment are presented.
　　　　　　　　　study　
Branching fraction
Mass spectrum (vector & scalar, M and width)　
t → Khn, Kp0hn (K*hn), and pp0hn
Lepton Flavor Violation in t decays
Prospect for Super-B
t- → Ks p- nt
In my talk, I’d like to cover three topics such as
1) check on the Lepton Universality 2) study of the 2pi mode, 3) the search for the Lepton Flavor Violation in tau decays
And the decays with Kaons if the time is allowed.
Nov. 27, 2007
BBCB Workshop

4. 4
1. t- → Ksp-nt study
Largest Br among decays with one K, it makes dominant contribution to the total strange hadronic spectrum function Sensitive to ms, Vus
Scalar resonance ? Necessary condition for CPV in t decay.
1-1 Events selections
Ks + p-, tag-side; lepton
sK---+++ttpppe/mnnn-e+e
( )
351/fb data
Nov. 27, 2007
BBCB Workshop 4

5. Two lepton (e,m) events are used for normalization.5
1-2 Branching fraction B(t → Ksp-nt )
Two lepton (e,m) events are used
for normalization.
B(t → K0p-n) = 2.0xB(t → KS0p-n)
= 0.808±0.004(stat.) ±0.026(syst.) %
Nov. 27, 2007
BBCB Workshop

6. M(K*(892)-) = 895.47±0.20(stat.) ±0.44(syst.) ±0.59(mod.) MeV/c2 6
1-3 Ksp- mass spectrum
K*(892) alone
Best fit is achieved in K*0(800)+K*(892)+K*(1410)/ K*0 (1430) but not K*(892) alone.
M(K*(892)-) = ±0.20(stat.) ±0.44(syst.) ±0.59(mod.) MeV/c2
G(K*(892)-) = 42.2±0.6(stat.) ±1.0(syst.) ±0.7(mod.) MeV
Nov. 27, 2007
BBCB Workshop

7. M(K*(892)-) = 895.47±0.20(stat.) ±0.44(syst.) ±0.59(mod.) MeV/c2
1-4 K*(892)- mass & width
M(K*(892)-) = ±0.20(stat.) ±0.44(syst.) ±0.59(mod.) MeV/c2
G(K*(892)-) = 42.2±0.6(stat.) ±1.0(syst.) ±0.7(mod.) MeV
PDG ±0.26 (896.00±0.25) ±0.9 (50.3±0.6)
K*± (K*0)
Nov. 27, 2007
BBCB Workshop

8. t → Ksp-nt Summary Lusiani talk8
Lusiani talk
Highly precise measurement of B(t→K0p-n) is performed.
Affects to the Vus value. Discussed by S. Banerjee (hep-ex/ )
K*(890)- mass is significantly different from the current world average value.
(Note: Other all measurements are from pure hadronic reactions.)
K*(892) alone is not sufficient to describe Ksp- mass spectrum, needs K0*(800) and
K*(1410) or K*0(1430). => Good news for CPV study in the Ksp system.
Our results
PDG-2007
B(t→K0p-n)
(0.808±0.004±0.026) %
(0.90±0.04) %
M(K(892)*-)
(895.47±0.20±0.44±0.59) MeV
(891.66±0.26) MeV
G(K(892)*-)
(46.2±0.6±1.0±0.7) MeV
(50.8±0.9) MeV
Nov. 27, 2007
BBCB Workshop

9. 2-1 Event selection with h→gg
2. t → Khn, Kp0hn (K*hn), and pp0hn study
Analyze t-decay modes, involving an h,
Because of poor statistics, previous measurements have large uncertainty.
Data used are 485/fb ( 433M t pairs ),　x ～100 larger than previously.
Physics motivations
- CVC hypothesis, 　
- Chiral Lagrangian approach with WZW anomaly,
-- 2nd class current for t-→p- h n study.
- High mass resonance. h g K– e– e+ t+ t-
2-1 Event selection with h→gg
Khn Kp0hn pp0hn
1-trk K p Ng
2g h h & p0
sig-side
tag-side
1-trk, Ng<2,
trk = m/e
　|Vthrust|>0.8; 　
Msig<Mt ; 　Mtag<Mt
(m/e)+
Nov. 27, 2007
BBCB Workshop

10. 2-2 h→gg yield measurement
May 10, 2007
Belle Analysis Meeting 10
2-2 h→gg yield measurement
Fit data with (signal=Crystal Ball function + BG=second-order polynomial function)
t→Khn
c2/dof=0.824
t→Kp0hn
c2/dof=0.988
c2/dof=0.936
t→pp0hn
Khn
Kp0hn
pp0hn
yields
1387 ± 44
270 ± 33
5959 ± 105
mass (MeV/c2)
544.9 ± 0.6
544.4 ± 1.0
544.3 ± 0.4
resolution (MeV/c2)
11.0 ± 0.6
10.7 ± 1.5
11.6 ± 0.3
Nov. 27, 2007
BBCB Workshop 10

11. 2-3 Extract Branching fractions11
2-3 Extract Branching fractions
Consider cross-feed among the decays,
(h-yield)-(qq+others)
Cross-feed rates
Detection efficiencies
detection eff. & cross-feed rates
Selection
Khn
Kp0hn
pp0hn
9.41×10-3
3.71×10-4
1.50×10-5
1.14×10-4
3.46×10-3
7.09×10-5
1.74×10-5
2.32×10-4
4.71×10-3
Efficiencies (e’s) include B(h →gg).
h-yield qq
others
Khn
Kp0hn
pp0hn
1387±43 (ev)
30.6±15.6
1.1±0.2
15.1±3.8
18.0±1.0
270±33
27.0±8.5
1.2±0.4
16.0±0.9
85.3±4.6
5959±105
212±29
71.6±20
2.4±0.1
9.4±2.4
Nov. 27, 2007
p-p0p0hn
BBCB Workshop

12. consistent 2-5 Systematic uncertainties (%) (1.61±0.05±0.09)×10-412
2-5 Systematic uncertainties (%)
Khn
Kp0hn
pp0hn
(h→gg)
(h→ppp)
contaminations of Khn ―
0.6
0.0018
contaminations of Kp0hn
0.3
0.4
0.042
contaminations of pp0hn
0.075
0.1
3.3
contaminations of pp0p0hn
contaminations of qq
1.5
6.0
0.5
K/p ID
2.8
2.2
1.0
lepton ID
2.3
2.6
tracking
1.3
luminosity
1.6
p0 detection
2.0
p0 veto
signal MC
1.7
0.7
B(h→p-p+p0)
1.8
Total
5.6
6.1
8.9
5.0
2-6 Branching fractions
Our results
Khn (h→gg) (h→p-p+p0)
(1.61±0.05±0.09)×10-4
(1.65±0.16±0.10)×10-4
Khn combined
(1.62 ± 0.10) ×10-4
Kp0hn
(4.7 ±1.1 ±0.4 )×10-5
pp0hn
(1.39±0.03±0.07)×10-3
consistent
Nov. 27, 2007
BBCB Workshop

13. B(K*-hn)=(1.10±0.19±0.07) ×10-4 t→Kp0hn decay is dominated by13
2-7 t→K(892)*-hn analysis
Continuum BG
t→Kp0hn decay is　dominated by
t →K(892)*hn
Efficiency (%)
K*- yields
K*-n BG
qq BG
0.115
119±19
2.3±0.9
6.5±2.3
Efficiency (e) include B(K*-→K-p0)=0.333, B(h→gg)=0.394, and B(t→lnn)=0.352.
Systematic
error (%)
peaking BG (tt)
0.94
peaking BG (qq)
2.4
K/p ID
2.2
lepton ID
2.5
tracking
1.3
luminosity
1.6
p0 detection
2.0
p0 veto
2.8
Signal MC
1.7
Total
6.1
B(K*-hn)=(1.10±0.19±0.07)
×10-4
Nov. 27, 2007
BBCB Workshop

14. Summary for decays involving h14
Summary for decays involving h
Precise B(t→K-hn; K-p0hn; K*hn; p-p0hn) measurements largely improve PDG07 data.
B(t→p-p0hn) agrees with a CVC calculation, 1.5x10-3 by Gilman.
Systematic theoretical study is awaited, along with new data.
Preliminary
Our results
PDG-2007
B(t→Khn)
(1.62±0.10) ×10-4
(2.7±0.6) ×10-4
B(t→Kp0hn)
(4.7±1.1±0.4)×10-5
(1.8±0.9)×10-5
B(t→K(892)*-hn)
(1.10±0.19±0.07)×10-4
(2.9±0.9)×10-4
B(t→pp0hn)
(1.39±0.03±0.07)×10-3
(1.77±0.24)×10-3
Nov. 27, 2007
BBCB Workshop

15. 3.Search for Lepton Flavor Violation
Sizeable LFV is expected in many extension of the SM
SUSY + vR, see-saw mechanism
Higgs dominated mechanism
Here We present updated searches based on
～530/fb data (preliminary)
t→m g, e g
t→３ｌ　　（ｌ＝e, m)
t→ l Vector (Vector =r, f, K*, w)
Nov. 27, 2007
BBCB Workshop

16. m g t General event selection  (signal)  LFV
generic t decay e- e+ t m g
signal side
tag side
 (signal)  LFV　
of exclusive decay mode
&  (tag)  single track
with (n g) + missing
Single prong mode occupies >80% of decay.
Simple but strong constraints does not exist due to neutrino missing .
BG’s: tt, continuum, mm, ee, gg, BB
signal evaluation: minv – DE
minv ~mtau & DE=E-Ebeam~0
Blind analysis
Evaluation of upper limit
The event selection is common. We require each LFV exclusive decay for signal side and the existence of the single track in the tag-side.
After requiring some cuts to reduce the background, the final signal evaluation is carried out in the two-dimensional plane of the invariant-mass
versus DE. The analysis is carried out by blinding the signal region when optimizing the signal selection criteria.
If there are no significant candidates, the upper limit is evaluated either by Feldman-Cousins method or by a maximum likelifood fit.
For small numbers of events in signal-region:
event-counting is done with Feldman-Cousins method.
For events >= a few 10’s in signal-region:
maximum likelihood fit is applied and upper-limit is evaluated with toy-MC.
Nov. 27, 2007
BBCB Workshop

17. search for tmg 535/fb remaining events: 71ev./(535/fb)
analysis: same with previous one,
but with tighter requirements
remaining events:
71ev./(535/fb)
signal detection eff: 6.7%
signal region: 2s ellipse
signal extraction: UEML fit:
s=-3.9, b=13.9
(allow negative s and its prob. 25%)
s(90% CL) = 2.0 ev
signal
data
DE (GeV)
blinded region
Mmg (GeV/c2)
projection
First we show the results with full data sample for mu gamma process.After appling the same selection criteria, 94 event is remained in this wide errea. The signal region is defined by the green ellipse which correspond the 2sigma. The projection of the blue band region is given in this figure, where the grey area is the expected signal distribution.
By making a fit with signal and background, the upper limit Br of mu gamma decay is determined to be 4.5 times 10to minus 8 at 90%C.L.
no signal events are found.
Br<4.5x10-8 at 90%C.L.(mg)
Nov. 27, 2007
BBCB Workshop

18. Search for teg 535/fb Remaining events: 55ev in 5s box
Signal detection eff: 3.0%
Signal region: 2s ellipse
Signal extraction: UEML fit:
s=-0.1, b=5.1
s(90% CL) = 3.3 ev
Br < 1.2x at 90% CL (e g)
Nov. 27, 2007
BBCB Workshop

19. Search for t3l 535/fb e-m+m- e-e+e- m-e+m-
Selection criteria is optimized for each modes.
m-m+m-
m-e+e-
m-e+e-
m-m+m-
Negligible BG
Keeping high
efficiency
Preliminary
For other modes such as 3lepton or one-lepton plus resonaces, the background is still negligible level. This is an exmaple for 3-leptons.
mode
e(%)
NBG
Nobs
S90
Br, 10-8
m- e+ m-
10.8
0.02
2.44
<2.3
m-e-e+
9.3
0.04
2.43
<2.7
m-m-m+
7.6
0.07
2.41
<3.2
e-m-m+
6.1
0.05
<4.1
m+e-e-
12.5
0.01
e-e-e+
6.0
0.40
2.10
<3.6
Nov. 27, 2007
BBCB Workshop

20. l + Vector meson (r, f, K* or w) 543/fb
Preliminary
m K*0
m f
m w
m r0
e f
e r0
e w
e K*0
BG is negligible except for mw and m r0 modes. The main BG for those modes is t→pw n for mw mode, and t →3pn+ qq continuum for mr0 mode, where one p is miss-identified as m.
Nov. 27, 2007
BBCB Workshop

21. l + (r, f, K* or w) results 543/fb
Preliminary
l + (r, f, K* or w) results /fb
mode
e(%)
NBG
Nobs
S90
Br, 10-8
m- f
3.1
0.11 1
4.2
<13
e- f
2.34
<7.6
m- w
2.5
0.19
2.27
<9.1
e- w
<0.09
4.34
<18
m- K*0
3.7
0.22
2.24
<6.1
e- K*0
3.0
0.05
2.42
<8.0
4.0
0.10
4.23
<11
3.2
<0.17
2.45
<7.7
m- r0
4.9
1.04
3.34
<6.9
e- r0
3.9
<0.12
2.46
<6.3
Nov. 27, 2007
BBCB Workshop

22. 4. Future prospect for LFV decays
Super-B factory
Background:
Still negligible for
t→３ｌ　　（ｌ＝e, m)
t→ l Vector
sensitivity improves as 1/L
Non negligible for t→m g, e g
but tradable.
Sensitivity
achieves area
Based on MC simulation assuming the current level of efficiency and background.
Nov. 27, 2007
BBCB Workshop

23. Monte Carlo simulation of t→m g signal at a Super-B.
t→m g
Br(t→mg)=10-8 is assumed.
Same level of current BG and efficiency
is assumed.
With 75/ab of data the significance
of such a decay is expected exceed
5 s.
Nov. 27, 2007
BBCB Workshop

24. Correlation: t-→ mg vs m- →eg
The correlation between Br(t →mg) and for Br(m→e g) provide a unique tool to identify the nature of the New Physics models.
MEG sensitivity
hep-ph/
Super-B sensitivity
LFV decay depends on the Physics at GUT scale
Once it is found, a model independent analysis for 3l case
(A.I. Sanda, hep-ph/ )
MnR = 4 x GeV
Nov. 27, 2007
BBCB Workshop

25. 謝謝
Nov. 27, 2007
BBCB Workshop

26. Backup: Vus from t data by Pich [previous value]
Br and spectrum measurements can determine both Vus and ms.
where
hep-ex/
Nov. 27, 2007
BBCB Workshop

27. 2-4 B(t →Khn) with h→p+p-p027
2-4 B(t →Khn) with h→p+p-p0
3-trk & Ng=2
1-trk = K
2g forms p0
sig-side p- p+ g g h K– t- e+ t+ e–
result of fitting
yield
241±21
mass (MeV/c2)
547.4±0.7
resolution(MeV/c2)
　7.5±0.4
(m/e)+
Efficiencies (e’s) include B(h →ppp).
h-yield qq
others
Khn
Kp0hn
pp0hn
e ’s
1.56×10-3
241±21 (ev)
9.1±2.2
<1.18
3.3±0.8
5.8±1.3
Nov. 27, 2007
BBCB Workshop

28. 　　　　LFV related paper
L. Calibbi et al., Phys. Rev. D 74, (2006)[hep-ph/ ] SO(10)
M. Blanke et al., JHEP 0705 (2007) [hep-ph/ ] Little Higgs
V. Cirigliano et al., Nucl. Phys. B763 (2007) 2287, MSSM
B. Grinstein et al., Nucl. Phys. B763 (2007) 35; B728 (2005) 121.
S. Antusch et al., JHEP 0611 (2006) 090.
E. Arganda and M.J. Herrero, Phys. Rev. D73 (2006)
M. Ciuchini et al., JHEP 0705 (2007) 112.
P. Paradisi, JHEP 0602 (2006) 050; 0510 (2005) 006.
Nov. 27, 2007
BBCB Workshop