Belle Upgrade Plan - An Overview - M.Yamauchi KEK January 2004 Super B Factory Workshop University of Hawaii, Honolulu
Belle Upgrade Plan - An Overview -
M.YamauchiKEK
January 2004Super B Factory Workshop
University of Hawaii, Honolulu
OutlineOutline
Introduction: motivation of the Introduction: motivation of the SuperKEKSuperKEKBB project project
Can we continue to use DC with L>10Can we continue to use DC with L>103535?? Belle upgrade planBelle upgrade plan Summary and conclusion Summary and conclusion
Discovery of CPV in B decays
Precise test of SMand search for NP
Study of NP effect in B and decays
Identification of SUSY breaking mechanism
time or
integrated luminosity
Yes!!
sin21, CPV in B,3, Vub, Vcb, bs,bsll, new states etc.
AnomalousCPV in bsss
NP discoveredat LHC (2010?)
Now150 fb-1
Grand scenario of B physics
if NP=SUSY
Penguin CPV - A Smoking Gun
Anomaly?
CPV in penguin decays
Belle (July 2003)
ACP(KS)=0.96±0.50
ACP(’KS)=0.43±0.27
ACP(J/KS)=0.731±0.057
Expected errors in ACP’s
ACP(KS, ’KS) = ACP(J/KS)
In SM,
New phase in penguin loop may change this relation.
KEKB
PEPII
Next B factory
Bd- unitarity
m(Bs) B->Ks B->Ms indirectCP
b->s direct CP
mSUGRA closed small small small small small
SU(5)SUSY GUT + R
(degenerate)
closed large small small small small
SU(5)SUSY GUT + R
(non-degenerate)
closed small large large large small
U(2) Flavor symmetry
large large large large large sizable
Unitarity triangle Rare decay
Pattern of the deviation from the SM predictionY.Okada
KEKB upgrade strategy
Present KEKB L=1034
2002 03 04 05 080706 09 10 11
L=2x1035
L~5x1035
∫Ldt =350fb-1ILER=1.5A
ILER=9.4A
ILER=9.4AConstraint: 8GeV x 3.5GeV wall plug pwr.<100MW crossing angle<30mrad
L=2x1034
ILER=1.5A
Crab crossing
One year shutdown to:install ante chamberincrease RFmodify IR
Increase RF
Higher luminosity collider will lead to:
Higher background
Higher event rate
Require special features to the detector.
- low p identification s reconstruction eff.
- hermeticity “reconstruction”
Detector uDetector upgpgraderade
- radiation damage and occupancy in the detectors
- fake hits and pile-up noise in the EM calorimeter
- higher rate trigger, DAQ and computing
Expected background
• SR and HOM• Particle background• Soft photons• Neutrons and muons
Vertex meas.
Tracking and PID devices
EM calorimeter
KL detector
SR and HOM Simulation works ok.Particle bkgnd. and soft ~ vac. pressure at IR beam current Increase by a factor of 20 is assumed.
Q1: Does DC work with L>1035?
• If NO,– Need Si tracker.– EM cal, solenoid and iron structure have to be
rebuilt!!
• If YES,– Upgrade the present Belle detector.
New detector
Does CDC work with L>1035 ?
r = 15cm
Layer
Hit
rat
e/w
ire (
k Hz)
Exp 27 Run 206
HER 1.1ALER 1.5AL=9.6x1033cm-1s-1
MainInner
Cathode
Charge-up of the gas
Layer
Num
ber
of h
its
Bhabha ev.
2000
2002
Layer 49
Layer 49
Layer 1
Layer 1
Layer 3
Layer 3
Radiation damage to the present CDC
Efficiency for Bhabha tracks
Gain drift
No rad. damage has been observedafter 0.2C/cm irradiation.
Track Reconstruction under High Background
5 10 15 200
Background factor
5 10 15 200
Background factor
0
20
40
60
80
100
Rec
onst
ruct
ion
eff.
(%
)
High pT (B) Low pT (BD(Ds))
will be improved by replacingthe inner part by Si.
MC + real background at Belle
Tentative conclusion
• Drift chamber can be used in L>1035 at r>15cm.
• The detector is designed as an upgrade of Belle detector.
Vertex detector upgrade
Issues: ● Occupancy < ~5% ● Better vertex resolution with wider coverage ● Low pT tracking
Pixel or striplet DSSD at the inner layers + 4-5 layers of conventional DSSD
L=46cm, R=8.8cmBeampipe rad.=15mm17º<<150º (=CDC)
SVD2
Present Belle SVD2Installed in October, 2003
Occupancy vs. R Occupancy vs. DSSD radius
1
10
100
1000
0 2 4 6 8
radius (cm)
occupancy (%)
VA1(Tp=1us)
VATA(Tp=0.5us)
Pipeline(150nswindow)
Pixel for R < 3cmPipeline for R < 10cm
Based on 7.3MRad annual dose(estimation by Karim) for 1cm BPx ~27 at the same radius
DSSD w/ analog pipeline readout (~4 layers)to cope with high occupancy.APV25 for CMS as the best candidates
CDC
Possible configuration of the inner detector
1cm
13mm
beampipe and2-layer pixel sensors
striplet as an alternative option
15cm
Fast z trigger from APV253cm
Drift chamber upgrade
• To reduce the occupancy,– Smaller cell chamber
– New gas with faster drift velocity CH4
• To improve the 3D tracking efficiency,– Charge division method using normal Au-plated W
wire
Lorentz angle?
Small Cell Chamber
Drift Velocity
• Two candidate gases were tested.– CH4 and He-CF4
• In case of He-CF4, higher electric field is necessary to get fast drift velocity.
• In case of CH4, faster drift velocity by factor two or more can be obtained, even in rather lower electric field.
dE/dx Resolution• The pulse heights for e
lectron tracks from 90Sr were measured for various gases.
• The resolutions for CH4
and He(50%)-C2H6(50%) are same.
• The resolution for He-CF4 is worse than Ar-b
ased gas(P-10).
Expected performance• Occupancy
– Hit rate : ~140kHz ~7kHz X 20 – Maximum drift time : ~150nsec 300nsec/2– Occupancy : 2% 140kHz X 150nsec = 0.02
• Momemtum resolution (SVD+CDC) Pt/Pt = 0.11Pt 0.30/[%] 0.19*(863/1118)2
• Energy loss measurement – 6.4% 6.9*(752/869)1/2
PID device
Issues: ● High background immunity ● >3 K separation up to 4GeV ● Thinner device, volume and X0
PID detector
Present Belle: Aerogel Cherenkov counter both for barrel and endcap.
TOP counter for barrel &Aerogel RICH for endcap
Requirements: - Thin detector with high rate immunity. - >3/K separation up to 4GeV/c. - low p / separation.
or finer segmentation TOF ~10ps
TOP (Time-of-Propagation) CounterTOP
Quart bar
ConceptConcept
PrototypePrototype
Beam Test ResultBeam Test ResultRing image can bereconstructed with X and TOP
Multianode PMTR5900-L16
Quartz bar(20×100×2 cm3)
MCP-PMT(MCP-PMT(R3809U-50) R3809U-50) TTS ~50psec @1.5TTTS ~50psec @1.5T
• Gain~ 3 x 10Gain~ 3 x 106 6 @[email protected]
Preliminary result.Appears at JPS Spring.
1p.e
2p.e
3p.e
Separability with TTS=50ps, photo cathode = bi-alkali @ r=1130mm.
readout : Forward, Backward and = 45o
EM calorimeter upgrade
Issues: - Radiation damage of CsI crystals - Pile-up noise of the counters - Fake
Radiation damage of CsI crystals
Barrel EndcapExpected dose
10-20% loss of the light outputis not critical for the calorimeterperformance.
Pile-up noise @ 1035/1036
Backward Barrel Forward(Noise per crystal)
Improvement by 1.5Is obtained from 0.5-1s sampling0.5-1s shaping time
Green: current det./ electronicsRed: future det./ electronics
Kuzmin(BINP)
Upgrade plan and expected performance
• Now– CsI(Tl) + PD + Preamp– Shaper&QT module + FB TDC
• SuperKEKB• Barrel (*)
– CsI(Tl) + PD + Preamp ~1000ns– Shaper&ADC +CoPPER
• Endcap– Pure CsI + tetrode ~30ns ( 1/30 of CsI(Tl) )– Shaper&ADC + CoPPER
noise : better 1/sqrt(30)~6
(*) If PID system becomes thiner, det. eff. will be improved.
KL upgrade
Issue:
• High rate immunity
KL Detector - scintillator strip geometry -
KL Detector - scintillatior tile geometry -
Light collection uniformity Geiger mode photodiode
/ KL detection 14/15 lyr. RPC+Fe
Tracking + dE/dx small cell + He/C2H5
CsI(Tl) 16X0
Aerogel Cherenkov counter + TOF counter
Si vtx. det. 3 lyr. DSSD
SC solenoid1.5T
8GeV e
3.5GeV e
Detector upgrade: baseline design
2 pixel lyrs. + 3 lyr. DSSD tile scintillator
pure CsI (endcap)
remove inner lyrs.
“TOP” + RICH
New readout and computing systems
Summary
• SuperKEKB with L~1035 -1036 is considered.- Precision test of KM unitarity- Search for new physics in B and decays
- Study flavor structure of new physics
• Detector design is in progress for all the detector components of Belle, assuming that drift chamber is usable as a central tracking device.– Vertexing detector: “striplet” + APV25 or pixel– Central drift chamber: small cell + faster gas– PID device: TOP(B) + Aerogel RICH(E)– EM calorimeter: Pure CsI + tetrode (E)– Scintillator KLM– Pipelined DAQ and computing system