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 @1.5T@1.5T

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