recent results from belle and status of superkekb/belle ii
DESCRIPTION
Recent results from Belle and Status of SuperKEKB/Belle II. Chengping Shen Univ. of Hawaii, Belle collaboration. Outline. David A twood, Isard D unietz, and Amarjit S oni [ PRL 78, 3257 (1997), PRD 63, 036005 (2001)]. First evidence of ADS B → DK. CKM and color suppressed. - PowerPoint PPT PresentationTRANSCRIPT
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Recent results from Belle and Recent results from Belle and Status of Status of SuperKEKB/Belle IISuperKEKB/Belle II
Chengping ShenUniv. of Hawaii, Belle collaboration
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OutliOutlinene
David Atwood, Isard Dunietz, and Amarjit Soni [PRL 78, 3257 (1997), PRD 63, 036005 (2001)]
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First evidence of ADS B → DK
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ɸɸ33/ɣ/ɣ is the least well measured of the unitarity angles. is the least well measured of the unitarity angles.
One of methods uses D→KOne of methods uses D→K++ππ--, ADS(, ADS(David Atwood, Isard Dunietz, and Am
arjit Soni ) mode [) mode [PRL 78, 3257 (1997), , PRD 63, 036005 (2001)], ], for which the effect of CP violation can be enhanced by the comparablfor which the effect of CP violation can be enhanced by the comparabl
e magnitudes of interfering amplitudes.e magnitudes of interfering amplitudes.
CKM and color suppressed
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9RDK measurement is an important
Input value for the ɸ3 angle determination
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Bs →J/Ψ(η, η', f0), Ds(*)+Ds
(*)-
(CP-eigenstates)
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17Difference in widths between two Bs-Bs mass eigenstates (time-independent)
18PRL105,201802(2010) 23.6fb-1
19PRL105,201802(2010) 23.6fb-1
20PRL105,201802(2010) 23.6fb-1
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(indirect measurement)
direct measurements
CDF and D0 measured Delta Gamma using the time distributions of Bs decays. This has no model dependence.
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X(3915)&& X(4350)in J/and J/ (first o
bserved at Belle)
X
X: JPC=0++,0-+,2++,2-+,…
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New peak in J/
X
M: 3914 3 2 MeV,
: 23 10 +2 MeV, Nres = 55 14 +2 MeV
Signif. = 7.7, Background only fit
ee++ee-- undetected undetected pptt balance required balance required
XX(39(391515))→J/→J/ψωψω in in γγγγ fusion? fusion?
PRL 104, 092001 (2010)
-8
-14
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Could it be the Z(3930) ( ) ?
M: 3914 3 2 MeV,
: 23 10 +2 MeV,
Nres = 55 14 +2 evts
M = 3929±5±2 MeV tot = 29±10±2 MeV Nsig = 64 ± 18 evts
DD
J/
PRL 96, 082003 (2006)
c2’
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-14
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X(3915) partial width
B(J/) = 69 16 +7 eV (JP=0+)
B(J/) = 21 4 +2 eV (JP=2+)
For comparison:: B(DD) = 180 50±30 eV
If X(3915) = Z(3930) = c2’ 0.08B(c2’J/)
B(c2’DD)
Huge for above-open-charm-threshold charmonium
-18
-5
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Could it be the Y(3930)?BKJ/PRL94, 182002
M≈3943 ± 17 MeV≈ 87 ± 34 MeV
B+
B0
M≈3915 ± 5 MeV≈ 33 ± 13 MeV
Good overlap withBaBar Y(3930) values
X(3915):
M: 3914 3 2 MeV,
: MeV,
PRL101, 082001PRD82, 011101
B+
B0
M≈3919 ± 5 MeV≈ 31 ± 12 MeV
281023
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K. Yi ICHEP 2010
m = MeV/c2
a 2nd one at
m=4275 MeV?
B(Y4140J/) 10%
(Y4140J/) 1.2 MeV
If B(B+K+ Y4140) B(B+K+J/)
B+ K+ J/
The CDF Y(4140)J/
D*D*ssDD**ss molecule? molecule? [cs[cscscs] tetraquark?] tetraquark?
29.20.3 /6.4143 cMeV
24.10
1.6 /3.15 cMeV
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Searched for Y(4140) in J/• No Y(4140) (efficiency is vNo Y(4140) (efficiency is v
ery low ~0.3%)ery low ~0.3%)
• White histograms are datWhite histograms are data, the shaded are normalia, the shaded are normalized zed and J/ and J/ sidebands sidebands eventsevents
• A few events accumulate A few events accumulate at 4.35 GeV in both J/at 4.35 GeV in both J/eee & e & modes modes
• Our upper limits disfavor Our upper limits disfavor the scenario Y(4140) beinthe scenario Y(4140) beingg
a Ds*a Ds*+ + Ds*Ds*--molecule with molecule with
JJPCPC=0=0++ ++ or 2or 2++++
[PRD80, 054019,2009][PRD80, 054019,2009]
JP=0+: ΓγγBr(Y(4140)) →J/) < 39 eV @ 90% C.L.JP=2+: ΓγγBr(Y(4140)) →J/) < 5.7 eV @ 90% C.L.
825 fb-1
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Fit to J/ invariant mass
1.14.6 1.33.2
7.06.4350 6.41.5
JP=0+: ΓγγBr(X(4350)) →J/) = eV
JP=2+: ΓγγBr(X(4350)) →J/) = eV
S.S.=3.9, const. bkgS.S.=3.2, linear bkg
825 fb-1
PRL 104, 112004 (2010)
• M= MeV/c2
• Γ= MeV/c2
• N (X(4350))=
•Excited P-wave charmonium? •Tetraquark? Fl. Stancu, arXiv: 0906.2485•D*
sD*s0 molecule at 4.34±0.09 GeV?
J.R.Zhang et al., arXiv:0905.4672
2.42.38.8
1.14.6 1.33.2
1.43.13 9.171.9
3.05.1 7.05.0
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e+e– to charm cross sections via ISR
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Use ISR to measure open charm exclusive final states
e-
e+ e+e+
e- s=(Ecm-E)2-p2
c c
ISR at B factories• Quantum numbers of final states are fixed JPC = 1– –
• Continuous ISR spectrum:– access to the whole √s interval
em suppression compensated by huge luminosity
– comparable sensitivity to energy scan (CLEOc, BES)
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DD DD* D*D*
DDπ
DD*π
Λ+c Λ
c
Sum of all exclusive contributions
Here D=D0 or D+ . The same for D*Only small room for unaccounted contributions
• Charm strange final states Limited inclusive data above 4.5 GeV
• Charm baryons final states
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• Full reconstruction of hadronic part
• ISR photon detection is not required
– but used if it is in the detector acceptance
• Translate measured Ds(*)+Ds
(*)- mass spectrum to cross section
• Ds+ are reconstructed using six decay modes: KsK+,K-K+π+, KsK-
π+ π+, η π + and η’ π +
e+e– →Ds(*)+Ds
(*)- via ISR
with full reconstructionγ
reconstructed
not reconstructed
if undetectable
Ds(*)+
s=E2cm-2EγEcm
e+
e–
e+
Ds(*)-
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Exclusive e+e–→Ds(*)+Ds
(*)- cross-sections
• A clear peak is seen at threshold near ψ(4040) mass in Ds+Ds
-
• Two clear peaks are seen at the ψ(4160) and the ψ(4415) masses in Ds
+Ds*-
• With limited statistics no structure are evident in Ds*+Ds*-
• Both the e+e-→ Ds+Ds*- cross section and R ratio exhibit an obvious dip
near the Y(4260) mass, similar to what is seen in e+e-→D*D* and in the total cross section for charm production.
arXiv:1011.4397 (accepted by PRD)
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Status of Status of SuperKEKB/Belle IISuperKEKB/Belle II
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• What is the next experimental step? Precision measurements
• Much larger sample needed for this purpose Super B factory
• Hopefully new phenomena might be seen:
– CPV in B and D decays from the physics outside the CKM scheme.
– Lepton flavour violations in decays.
• Physics models can be identified (if new effects are observed) or new ones can be constrained (if nothing is seen).
• Physics motivation is independent of LHC.
– If LHC finds NP, precision flavour physics is compulsory.
– If LHC finds no NP, high statistics B/ decays would be a unique way to search for the physics far beyond the TeV scale.
Further Continuation of Flavour Physics Further Continuation of Flavour Physics possible at a Super B Factorypossible at a Super B Factory
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How to do it? => Upgrade KEKB & BelleHow to do it? => Upgrade KEKB & Belle
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e- 7GeV 2.6 A
e+ 4GeV 3.6 A
Target: L = 8x1035/cm2/s
SuperKEKB
Colliding bunches
Damping ring
Low emittance gun
Positron source
New beam pipe& bellows
Belle II
New IR
TiN-coated beam pipe with antechambers
Redesign the lattices of HER & LER to squeeze the emittance
Add / modify RF systems for higher beam current
New positron target / capture section
New superconducting /permanent final focusing quads near the IP
Low emittance electrons to inject
Low emittance positrons to inject
Replace short dipoles with longer ones (LER)
SuperKEKB colliderSuperKEKB collider
The improvement in luminosity is due to the dramatic reduction of The improvement in luminosity is due to the dramatic reduction of beam size (beam size (σσyy ~1 micron -->50 nanometer) ~1 micron -->50 nanometer)
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21-24 Oct 2010 Charm2010
Plan and Expectation with SuperKEKBPlan and Expectation with SuperKEKB
Milestone of SuperKEKB
We will reach 50 ab-1
in 2020~2021.9 month/year20 days/month
Inte
gra
ted L
um
inosi
ty(a
b-1)
Peak
Lum
inosi
ty(c
m-2s-
1)
Commissioning starts In later half of 2014
Shutdownfor upgrade
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Status: TerminationStatus: Termination of KEKB on June 30, 2010 of KEKB on June 30, 2010 marked the start of SuperKEKB/BelleIImarked the start of SuperKEKB/BelleII
First physics run on June 2, 1999Last physics run on June 30, 2010Lpeak = 2.1x1034/cm2/sL > 1ab-1
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• 5.8 oku yen (M$) for Damping Ring (FY2010)• 100 oku yen (M$) for machine: Very Advanced
Research Support Program approved for FY2010-2012• 2010-2013: construction, installation• 2014(later half): commissioning
Funding and ConstructionFunding and Construction
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New Collaboration (Belle II)New Collaboration (Belle II)Belle II is a new international collaboration 360360 members members - 57 - 57 institutions institutions Regular collaboration meetings TDR (Technical Design Report) has been published
(arXiv:1011.0352arXiv:1011.0352)
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SummarSummaryy
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backup
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All possible two-body decays of ψ(3770), ψ(4040), ψ(4160), ψ(4415) are included
Significant effect of interference : model dependent!
To reduce model dependence
we need to measure exclusive cross sections to ope
n charm final states
Resonance shapes Interference term
Rres=RBW+Rint
Phys.Lett.B660,315(2008) BES fit to the inclusive R spectrum
Parameters of the JPC = 1– – conventional charmonia
ψ(3770), ψ(4040), ψ(4160), ψ(4415)
M, Γtot, Γee remain quite uncertain and model dependent
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How to improve luminosity?
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Zhen-An Liu 21-24 Oct 2010 Charm2010 54
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Belle II:Belle II:Belle Upgrade for the Super KEKBBelle Upgrade for the Super KEKB
SC solenoid1.5T
New readout and computing systems
CsI(Tl) 16X0
pure CsI (endcap)
new electronics (waveform sampling)
Aerogel Cherenkov counter + TOF counter
→ “TOP”
+ Aerogel RICH
Si vtx. det. 4 lyr. DSSD→ 2 DEPFET pixel lyrs. + 4 lyr. DSSD
/ KL detection 14/15 lyr. RPC+Fe
→ tile scint.
TDR: KEK Report 2010-1
CDC: Tracking + dE/dx small cell + He/C2H6
remove inner lyrslarge outer radiusfaster timingsmaller cell
→