Recent Update
pin Belle
S. Nishida
KEK
KEKB Review
Dec. 3, 2007
S.Nishida (KEK)
Dec. 3, 2007

Recent Update in Belle

KEKB Review

1

Contents
Introduction
B0 → D*–τ+ν (another missing energy decays)
Discovery of more New Particles
Particles.
Results from ϒ(5S) data.
D0-D0 mixing
Summary
There are many other new results in mixing induced CP
violations, rare decays, charm and τ physics …,
which cannot be covered in this talk.

S.Nishida (KEK)
Dec. 3, 2007

Recent Update in Belle

KEKB Review

2Belle Collaboration
BINP
Chiba U.
U off CiU.
Cincinnatiiti
Ewha Womans U.
Fu-Jen Catholic U.
U. of Giessen
Gyeongsang Nat’l U.
Hanyang U.
U. of Hawaii
Hiroshima Tech.
Tech
IHEP, Beijing
IHEP, Moscow

IHEP, Vienna
ITEPK
Kanagawa
U
U.
KEK
Korea U.
Krakow Inst. of Nucl. Phys.
Kyoto U.
Kyungpook Nat’l U.
EPF LausanneJozef Stefan Inst.
Inst / U.
U ofLjubljana / U. of Maribor
U. of Melbourne

Nagoya U.
Nara Women’s U.
National Central U.
National Taiwan U.
National United U.
Nihon Dental CollegeNii t U.
Niigata
UNova Gorica
Osaka U.
Osaka City U.
Panjab U.
Peking U.
Princeton U.
Riken
Saga U.
USTC

Seoul National U.
Shinshu U.
Sungkyunkwan
g yU.
U. of Sydney
Tata InstituteToho U.
Tohoku U.
UTohuku Gakuin U.
U. of Tokyo
Tokyo Inst. of Tech.
Tokyo Metropolitan U.
Tokyo U. of Agri. and Tech.
INFN Torino
Toyama Nat’l
Nat l College
VPI
Yonsei U.

14 countries
countries, 55 institutes
institutes, ~400 collaborators

S.Nishida (KEK)
Dec. 3, 2007

Recent Update in Belle

KEKB Review3Belle Detector
Particle
IdentificationenergyParticle
Identification
momentumParticle
Identification

vertexKL ,  detection

General purpose detectors for various B, charm, τ physics.
S.Nishida (KEK)
Dec. 3, 2007

Recent Update in Belle

KEKB Review

4B0 → D*–τ+ν
Decay of B meson to τ lepton.
Interaction of quark and lepton in 3rdgeneration
9 Test of the Standard ModelModel.
9 Sensitive to the New Physics.
z Last year,year Belle founds the evidence ofB– → τ–ν decays.
zHowever, this kind of measurement is experimentally very
challenging
B+ → τ+ντ
τ+ → e+νeντ→ π+ντS.Nishida (KEK)
Dec. 3, 2007

Always more than 1 neutrinos
i theinth fifinall statet t

Recent Update in Belle

KEKB Review5

B0 → D*–τ+νFull reconstruction technique(th example(thel bbelowl
iis bbasedd on B → τν))
π+e+
K-

B+

8GeV e-reconstruct the
opposite side

S.Nishida (KEK)
Dec. 3, 2007

ντ3.5GeV e-

B-π-πντIn usual analyses,
we only look at
the signal side.
HHowever,iin ththemode with >1neutrinos,ti
we alsolreconstruct theopposite site BB.

π+νeRecent Update in Belle

KEKB Review

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B0 → D*–τ+νKDππτ
BY(4S)( )Beνννπreconstruct the other sidein hadronic mode

decay mode in interest

Thiss method
et od iss posspossible
beoonlyy in B factory
acto y eexperiments.
pe e tsz The drawback of this method is very low efficiency (~ O(0.1%)) ofthe B reconstruction.
z However, still possible thanks to excellent luminosity of KEKB!!
zS.Nishida (KEK)
Dec. 3, 2007

Recent Update in Belle

KEKB Review

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B0 → D*–τ+νB0 → D*–τ+ν

Sensitive to charged Higgs.
z New Physics at Tree level.
z Some sensitive observables (e.g. τ polarization)z Expected branching fraction : 1.2% ~ 1.6%zAnalysis strategy

Slightly different approachcompared to B– → τ–ν
S.Nishida (KEK)
Dec. 3, 2007

Recent Update in Belle

KEKB Review

8B0 → D*–τ+ν
Background suppression using visible energy / missing massb f
beforecutt

after
ft cutt

ResultFirst observation !
[PRL 99, 191807 (2007)]
S.Nishida (KEK)
Dec. 3, 2007

Recent Update in BelleKEKB Review

9X(3872)
B Factories have been found new particle (resonances).
z X(3872) was first observed by Belle in 2003
2003, and was confirmed byBaBar, CLEO and CDF.
00 0 0z Decays to ππJ/ψ, πππ J/ψ, γJ/ψ, D D π are known.
z X(3872) is naively considered to be made of cc.
z However,, there seems to be no corresponding
pgq
quarkonium stateaccording to the theoretical calculation.
z Possible explanation:
pz DD* meson molecular statez 4-quark stateX(3872)z hybrid (ccg), glue ball (gg)S.Nishida (KEK)
Dec. 3, 2007

Recent Update in Belle

KEKB Review

10X(3872)
What Belle can do is to measure properties of this exotic state.
e.g) X(3872) is likely to have JPC = 1++, because
X decays to γJ/ψ, and hence C=+1
P = 1+z Angular distribution favors Jz

X(3872) in B decays:
In some models,, the mass of X(3872)() is different between B0 and
B+ decays, if X is a 4-quark state.
( B+) – m(X( B0) = ((8 ± 3)) MeVΔm ≡ m(X0z The decay from B is suppressed if it's a D*D molecular state.
R ≡ B(B0 → K0X)/B(B+ → K+X) < 0.1zS.Nishida (KEK)
Dec. 3, 2007

Recent Update in Belle

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X(3872)
New Belle result with 657M BB
data sample
X(3872) is reconstructed via J/ψπ+π–00
z First observation of B → K X(3872)
z No mass splittingΔm ≡ m(XB+) – m(XB0)= (0.22 ± 0.90 ± 0.27) MeV
z Neutral mode is not suppressed
R ≡ B(B0 → K0X)/B(B+ → K+X)
=00.949 ±00.24 ± 00.100z'M
S.Nishida (KEK)
Dec. 3, 2007

Recent Update in Bellem(X) – m(J/ψ)
KEKB Review

12Friends of Y(4260)
New resonances are also
searched for by using ISR+ −e e → γ ISRY
process.
Y(4260) discovered byY (4008)

548fb −1e

γ ISR

−

γe++ −
Y→ππ ψ (2S )Y (4360)
673fb −1

Y (4660)

Y → π π J /ψ+−[PRL 99, 182004 (2007)]
S.Nishida (KEK)
Dec. 3, 2007

Y

[arXiv:0707.3699]

Recent Update in Belle

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Z(4430)
New resonances are also searched in many other decays of B meson,
and is found in the ψ
ψ'π+K– final state:

M2(ψψ'π) [GeeV2]

23K*(892)
K?*(1430)

20

B0 → ψ'π–K+?

17140S.Nishida (KEK)
Dec. 3, 2007

12M2(Kπ) [GeV2]

3Some structure (?) is seen inthe Dalitz plot of
B0 → ψ'π–K+ decays

Recent Update in Belle

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Z(4430)
Clear signature of a resonanceat 4430 MeV!!
→ named as Z(4430)
Npeak = 124 ± 30 eventsz M = 4433 ± 4 ± 1 MeV+17 +30z Γ = 44–13 –11 MeVzZ(4430) is a charged particle!!
Not cc (because of charge)z Likely to be 4-quark state!
zS.Nishida (KEK)
Dec. 3, 2007

Recent Update in Belle

KEKB Review15

Physics at ϒ(5S)
Belle accumulated ~23 fb-1 ϒ(5S) data.
e+e- → ϒ(4S) → BB(B=B+, Bd0)

ϒ(4S)
ϒ(5S)

e+e- → ϒ(5S) → BB, B*B, B*B*, BBπ,BBππ, BsBs, Bs*Bs, Bs*Bs*(B*→Bγ, Bs*→Bsγ)
Opened a new window to Bs physics.
NNew
result:lt fifirstt observation
bti off radiativedi ti B
Bs ddecays!!
!!
+1.2–5B(Bs → φγ) = (5.7 +1.8)
×10–1.5 –1.7(5.5σ)

Signal yield 18 ± 6.

S.Nishida (KEK)
Dec. 3, 2007

Recent Update in Belle

KEKB Review16ϒ(5S) →ϒ(1S,2S)π+π−ϒ(5S) decay can also be studied.

B(ϒ(4S) → ϒ(1S,2S) π+π− ) ~ 1 ×10–4
So, the expectation isB(ϒ(5S) → ϒ(1S,2S) π+π− ) ~ 2 ×10–5

However,, we are seeingg theϒ(5S) signal in data!!
If the signal comes from ϒ(5S)
B(ϒ(5S) → ϒ(1S)π+π− )= (0.53(± 0.03 ± 0.05)%)%B(ϒ(5S) → ϒ(2S)π+π− )= (0.78 ± 0.06 ± 0.11)%
Maybe, bottom version of“Y” resonance (Yb) ??
Need scan!
S.Nishida (KEK)
Dec. 3, 2007

Recent Update in Belle

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D0 Mixing
Mixing of neutral mesons wasobserved in K0, Bd0, Bs0, but
not in D0 meson.

ucD0W

uToo small in the SMSM.
0zD mixing has been searched in B factories.
B factories are also charm factories!
zD0WcD0 mixingg is often expressed
pin terms of two p
parameters,, x and yy.

non-zerononzero x or y = mixing
In SM, both x and y is < 1%.
S.Nishida (KEK)
Dec. 3, 2007

Recent Update in Belle

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D0 Mixing
One of the way to measure D0 mixing
is to measure lifetime difference:τ ( D 0 → K −π + )yCP =−10−+τ (D → K K )Decayy time is measured from thepositions of D* vertex and D vertex.
− + is CP even final state.
z K K
0 system, y = yz In case of no CP violation in DCP.
z

τ = 410.1±1.5 fs

Other approach:0(*)ℓν
zD →K
0 K +π −zD →K+0.09 + 0.10+0.08+ 0.06
0+ −x
=0.
80
±0.
29
y=0.
33±0.
24
zD →K π π− 0.07 − 0.14− 0.12 − 0.08 (2.4σ)
S
S.Nishida (KEK)
Dec. 3, 2007

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D0 Mixing
Result:first evidence!!

y CP = (1 .31 ± 0 .32 ± 0 .25 )%((Siginficanceg3.2σ))[PRL 98, 211803 (2007)]If we combine other measurements,mixing is established with ~5σ

S.Nishida (KEK)
Dec. 3, 2007

Recent Update in Belle

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SummaryFirst observation B0 → D*–τ+ν
Evidence of D0-D0 mixing
Precise test of the standard model and pprobe toNew Physics
More new (charmoniuum-like) particles.
g Z(4430)() is a 4-quarkq)
New chargedstate ((?).
New results on Bs decays using Belle’s data at ϒ(5S).
(1S 2S)π+π−
Anomalously large rate to ϒ(1S,2S)
yg g on.
More analyses
are going
Stay tuned with new results!
S.Nishida (KEK)Dec. 3, 2007

Recent Update in Belle

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Backupp

S.Nishida (KEK)
Dec. 3, 2007

Recent Update in Belle

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CP Violation in the SM
Complex phase in the quark mixing matrix Kobayashi-Maskawa
Theory (1973)→ source of CPV in Weak Interactions
Requires 3 (or more) generation of quarks•

only 3 quaks (u, d, s) were known at that time!
• all 6 quarks are discovered.

CKM Matrix

S.Nishida (KEK)
Dec. 3, 2007

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Time Dependent CP Asymmetry
B0qpfCPB0

CP Violation manifests itself inproper-time difference (Δt)
distributions of two B meson
decays.

Γ (B (Δt ) → f CP ) − Γ (B (Δt ) → f CP )AC ≡
Γ (B (Δt ) → f CP ) + Γ (B (Δt ) → f CP )P0d0d0d0d= S ssin(ΔmΔt)(t) + A cos (ΔmΔt)(t)
Mixing induced CPV

S.Nishida (KEK)
Dec. 3, 2007

Direct CPV

Recent Update in Belle

2ImλCPS=
1+ |λCP|2|λCP|2 -1
A=|λCP|2 +1q A(B0→ fCP)
λCP = pA(B0→ fCP)

KEKB Review24Measurement of sin2φ1ACP(Δt) = S sin(ΔmΔt) + A cos(ΔmΔt)

B0 → J/ψ KS/L
B0bcJ/ψ
csKS/KLdWdb→sbt

dS.Nishida (KEK)
Dec. 3, 2007

precise measurement of φ1
In the SM,
S = -ξξ sin(2φ1)

w

B0it t )S = -ξ sin(2φ1) (ξ : CP eigenstate)
A=0gsssdφ, η’KS/KL

However, the value will changewith non-SM contribution to the loop
Search for New Physics

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CPV in penguinb →spenguin
657 MBBpenguinMBB
B 0 → K S0 K S0 N657
sig = 58 ± 11ACP(ΔΔt)

N sig = 307 ± 32ACP(ΔΔt)

B 0 → K S0π 0π 0b →dpreliminary

preliminary

S = +0.43 ± 0.49 ± 0.09
A = −0.17 ± 0.24 ± 0.06

S = −0.38 ± 0.77 ± 0.08
A = −0.38 ± 0.38 ± 0.05

2.0σ difference from the SM

Consistent with the SM

predicton:
S=−sin2φ1؄−0.68
S.Nishida (KEK)
Dec. 3, 2007

arXiv:0708.1845
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sin2φ1 Summary
Tree-penguin
Treepenguin difference
is now 0.1σ

the difference is 2.2σ if
we exclude this result:simple average is toonaïve
ï becausebththe error
is non-gaussian

S.Nishida (KEK)
Dec. 3, 2007

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B → ργ, ωγ

S.Nishida (KEK)
Dec. 3, 2007

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B → ργ, ωγ

S.Nishida (KEK)
Dec. 3, 2007

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