Belle Upgrade Plan

1
Belle Upgrade Plan - An Overview -
M.Yamauchi KEK January 2004 Super B Factory
Workshop University of Hawaii, Honolulu
2
Outline

• Introduction motivation of the SuperKEKB project
• Can we continue to use DC with Lgt1035?
• Belle upgrade plan
• Summary and conclusion

3
Grand scenario of B physics
Identification of SUSY breaking mechanism
Anomalous CPV in bgsss
if NPSUSY
sin2f1, CPV in Bgpp, f3, Vub, Vcb, bgsg, bgsll,
new states etc.
Study of NP effect in B and t decays
time or integrated luminosity
Precise test of SM and search for NP
Yes!!
NP discovered at LHC (2010?)
Discovery of CPV in B decays
Now 150 fb-1
4
Penguin CPV - A Smoking Gun
Anomaly?
5
CPV in penguin decays
Expected errors in ACPs
In SM,
ACP(fKS, hKS) ACP(J/yKS)
New phase in penguin loop may change this
relation.
Belle (July 2003)
ACP(fKS)-0.960.50 ACP(hKS)0.430.27
ACP(J/yKS)0.7310.057
KEKB PEPII
Next B factory
6
Y.Okada
Pattern of the deviation from the SM prediction
Unitarity triangle
Rare decay
Bd- unitarity e D m(Bs) B-gtfKs B-gtMsg indirect CP b-gtsg direct CP
mSUGRA closed small small small small small
SU(5)SUSY GUT nR (degenerate) closed large small small small small
SU(5)SUSY GUT nR (non-degenerate) closed small large large large small
U(2) Flavor symmetry large large large large large sizable
7
KEKB upgrade strategy
L5x1035
Constraint 48GeV x 3.5GeV 4wall plug
pwr.lt100MW 4crossing anglelt30mrad
ILER9.4A
ILER9.4A
Increase RF
L2x1035
One year shutdown to 4install ante
chamber 4increase RF 4modify IR
ILER1.5A
L2x1034
Present KEKB L1034
Crab crossing
ILER1.5A
?Ldt 350fb-1
2002
03
04
05
08
07
06
09
10
11
8
Detector upgrade
Higher luminosity collider will lead to
4 Higher background 4 Higher event rate 4
Require special features to the detector.

• radiation damage and occupancy in the detectors
• fake hits and pile-up noise in the EM calorimeter

- higher rate trigger, DAQ and computing

• low p m identification f smm reconstruction
  eff.
• hermeticity f n reconstruction

9
Expected background
Vertex meas. Tracking and PID devices EM
calorimeter KLm detector

• SR and HOM
• Particle background
• Soft photons
• Neutrons and muons

SR and HOM g Simulation works ok. Particle bkgnd.
and soft g vac. pressure at IR ? beam current

Increase by a factor of 20 is assumed.
10
Q1 Does DC work with Lgt1035?

• If NO,
• Need Si tracker.
• EM cal, solenoid and iron structure have to be
  rebuilt!!
• If YES,
• Upgrade the present Belle detector.

New detector
11
Does CDC work with Lgt1035 ?
Charge-up of the gas
Exp 27 Run 206
HER 1.1A LER 1.5A L9.6x1033cm-1s-1
Hit rate/wire(kHz)
Cathode
Inner
Main
Layer
r 15cm
12
Radiation damage to the present CDC
Gain drift
Efficiency for Bhabha tracks
Bhabha ev.
Number of hits
Layer
No rad. damage has been observed after 0.2C/cm
irradiation.
13
Track Reconstruction under High Background
MC real background at Belle
High pT (Bgpp-)
Low pT (BgD-(gDps)p)
100
80
60
Reconstruction eff. ()
40
20
0
5
10
15
20
0
5
10
15
20
0
Background factor
Background factor
will be improved by replacing the inner part by
Si.
14
Tentative conclusion

• Drift chamber can be used in Lgt1035 at rgt15cm.
• The detector is designed as an upgrade of Belle
  detector.

15
Vertex detector upgrade
Issues ? Occupancy lt 5 ? Better vertex
resolution with wider coverage ? Low pT
tracking g Pixel or striplet DSSD at the inner
layers 4-5 layers of conventional
DSSD
16
Present Belle SVD2
Installed in October, 2003
SVD2
L46cm, R8.8cm Beampipe rad.15mm 17ºltqlt150º
(CDC)
17
Occupancy vs. R
Based on 7.3MRad annual dose (estimation by
Karim) for 1cm BP x 27 at the same radius
Pixel for R lt 3cm Pipeline for R lt 10cm
18
Possible configuration of the inner detector
DSSD w/ analog pipeline readout (4 layers) to
cope with high occupancy. APV25 for CMS as the
best candidates
CDC
15cm
Fast z trigger from APV25
3cm
beampipe and 2-layer pixel sensors striplet as
an alternative option
19
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?
20
Small Cell Chamber
21
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.

22
dE/dx Resolution

• The pulse heights for electron 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-based
  gas(P-10).

23
Expected performance

• Occupancy
• Hit rate 140kHz ? 7kHz X 20
• Maximum drift time 150nsec ? 300nsec/2
• Occupancy 2 ? 140kHz X 150nsec 0.02
• Momemtum resolution (SVDCDC)
• sPt/Pt 0.11Pt ? 0.30/b ? 0.19(863/1118)2
• Energy loss measurement
• 6.4 ? 6.9(752/869)1/2

24
PID device
Issues ? High background immunity ? gt3s pK
separation up to 4GeV ? Thinner device, volume
and X0
25
PID detector
Requirements - Thin detector with high rate
immunity. - gt3s p/K separation up to 4GeV/c.
- low p p/m separation.
TOP counter for barrel Aerogel
RICH for endcap
Present Belle Aerogel Cherenkov counter both
for barrel and endcap.
or finer segmentation TOF 10ps
26
TOP (Time-of-Propagation) Counter
Concept
Beam Test Result
Ring image can be reconstructed with X and TOP
TOP
Quart bar
Prototype
Multianode PMT R5900-L16
Quartz bar (201002 cm3)
27
MCP-PMT(R3809U-50) TTS 50psec _at_1.5T
Preliminary result. Appears at JPS Spring.

• Gain 3 x 106 _at_1.5T

28
Separability with TTS50ps, photo cathode
bi-alkali _at_ r1130mm.

• readout Forward, Backward and q 45o

29
EM calorimeter upgrade
Issues - Radiation damage of CsI crystals -
Pile-up noise of the counters - Fake g
30
Radiation damage of CsI crystals
10-20 loss of the light output is not critical
for the calorimeter performance.
Barrel
Endcap
Expected dose
31
Pile-up noise _at_ 1035/1036
(Noise per crystal)
Kuzmin(BINP)
Backward Barrel
Forward
Improvement by 1.5 Is obtained from 0.5-1ms
sampling 0.5-1ms shaping time
Green current det./ electronics Red
future det./ electronics
32
Upgrade plan and expected performance

• Now
• CsI(Tl) PD Preamp
• ShaperQT module FB TDC
• SuperKEKB
• Barrel ()
• CsI(Tl) PD Preamp t1000ns
• ShaperADC CoPPER
• Endcap
• Pure CsI tetrode t30ns ( 1/30 of
  CsI(Tl) )
• ShaperADC CoPPER

snoise better 1/sqrt(30)6
() If PID system becomes thiner, g det. eff.
will be improved.
33
(No Transcript)
34
(No Transcript)
35
KLm upgrade

• Issue
• High rate immunity

36
KLm Detector - scintillator strip geometry -
37
KLm Detector - scintillatior tile geometry -
Light collection uniformity
Geiger mode photodiode
38
Detector upgrade baseline design
Aerogel Cherenkov counter TOF counter
SC solenoid 1.5T
g TOP RICH
3.5GeV e
CsI(Tl) 16X0
g pure CsI (endcap)
8GeV e-
Tracking dE/dx small cell He/C2H5
g remove inner lyrs.
New readout and computing systems
Si vtx. det. 3 lyr. DSSD
m / KL detection 14/15 lyr. RPCFe
g 2 pixel lyrs. 3 lyr. DSSD
g tile scintillator
39
Summary

• SuperKEKB with L1035 -1036 is considered.
• - Precision test of KM unitarity
• - Search for new physics in B and t 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