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Belle Upgrade Plan - An Overview -

Belle Upgrade Plan - An Overview -. M.Yamauchi KEK January 2004 Super B Factory Workshop University of Hawaii, Honolulu. Outline. Introduction: motivation of the SuperKEKB project Can we continue to use DC with L>10 35 ? Belle upgrade plan Summary and conclusion.

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Belle Upgrade Plan - An Overview -

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  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 L>1035? • Belle upgrade plan • Summary and conclusion

  3. Grand scenario of B physics Identification of SUSY breaking mechanism Anomalous CPV in bgsss if NP=SUSY 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 ACP’s In SM, ACP(fKS, h’KS) = ACP(J/yKS) New phase in penguin loop may change this relation. Belle (July 2003) ACP(fKS)=-0.96±0.50 ACP(h’KS)=+0.43±0.27 ACP(J/yKS)=+0.731±0.057 KEKB PEPII Next B factory

  6. Y.Okada Pattern of the deviation from the SM prediction Unitarity triangle Rare decay

  7. KEKB upgrade strategy L~5x1035 Constraint: 48GeV x 3.5GeV 4wall plug pwr.<100MW 4crossing angle<30mrad ILER=9.4A ILER=9.4A Increase RF L=2x1035 One year shutdown to: 4install ante chamber 4increase RF 4modify IR ILER=1.5A L=2x1034 Present KEKB L=1034 Crab crossing ILER=1.5A ∫Ldt =350fb-1 2002 03 04 05 06 07 08 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 pm identification f smm reconstruction eff. • hermeticity fn “reconstruction”

  9. Expected background • SR and HOM • Particle background • Soft photons • Neutrons and muons Vertex meas. Tracking and PID devices EM calorimeter KLm detector 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 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

  11. Does CDC work with L>1035 ? Charge-up of the gas Exp 27 Run 206 HER 1.1A LER 1.5A L=9.6x1033cm-1s-1 Hit rate/wire(kHz) Cathode Inner Main Layer r = 15cm

  12. 2000 Layer 49 Layer 1 Layer 3 Layer 49 Layer 1 2002 Layer 3 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 (Bgp+p-) Low pT (BgD*-(gDps)p+) 100 80 60 Reconstruction eff. (%) 40 20 0 0 5 10 15 20 0 5 10 15 20 Background factor Background factor will be improved by replacing the inner part by Si.

  14. Tentative conclusion • Drift chamber can be used in L>1035 at r>15cm. • The detector is designed as an upgrade of Belle detector.

  15. Vertex detector upgrade Issues: ● Occupancy < ~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 L=46cm, R=8.8cm Beampipe rad.=15mm 17º<q<150º (=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 < 3cm Pipeline for R < 10cm

  18. 1cm 13mm 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 (SVD+CDC) • 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 ● >3spK separation up to 4GeV ● Thinner device, volume and X0

  25. PID detector Requirements: - Thin detector with high rate immunity. - >3s p/K separation up to 4GeV/c. - low pp/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 Ring image can be reconstructed with X and TOP Beam Test Result TOP Quart bar Prototype Multianode PMT R5900-L16 Quartz bar (20×100×2 cm3)

  27. 1p.e 2p.e 3p.e MCP-PMT(R3809U-50) TTS ~50psec @1.5T Preliminary result. Appears at JPS Spring. • Gain~ 3 x 106 @1.5T

  28. Separability with TTS=50ps, photo cathode = bi-alkali @ r=1130mm. 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 @ 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 • Shaper&QT module + FB TDC • SuperKEKB • Barrel (*) • CsI(Tl) + PD + Preamp t~1000ns • Shaper&ADC +CoPPER • Endcap • Pure CsI + tetrode t~30ns ( 1/30 of CsI(Tl) ) • Shaper&ADC + CoPPER snoise : better 1/sqrt(30)~6 (*) If PID system becomes thiner, g det. eff. will be improved.

  33. KLm upgrade Issue: • High rate immunity

  34. KLm Detector - scintillator strip geometry -

  35. KLm Detector - scintillatior tile geometry - Light collection uniformity Geiger mode photodiode

  36. 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. RPC+Fe g 2 pixel lyrs. + 3 lyr. DSSD g tile scintillator

  37. Summary • SuperKEKB with L~1035 -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

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