1. Status of Belle Super KEKB plan SLAC seminar March 21 st, 2003 Nobu Katayama KEK

2. March 21st, 2003Nobu Katayama2 Outline § Belle/KEKB status –General –Beam pipe accident –SVD2 § Recent physics results § Super KEKB plan –Physics –Detector study –Accelerator study

3. March 21st, 2003Nobu Katayama3 KEKB status 1999/10  2003/3/18 > 50 fb  1 in a year 2002 >50 fb  1 in 2002 LER>1.55A HER>1A with SRF IP leak: Longest unscheduled shutdown Oct.30~Dec 2002

4. March 21st, 2003Nobu Katayama4 Best day (03/17/2003) 462pb  1 /day recorded NK on shift!

5. March 21st, 2003Nobu Katayama5 Beam pipe accident § 6AM, Oct. 29, 2003:New record:8.26  10 33 § Oct. 30:A vacuum problem happened § Oct. 31:A serious problem happened –After an abort, HER beam could not be injected –Leak check showed no leak –Resumed running (vacuum scrubbing) –But too much background to the detector –Beam aperture check: something inside? § Nov. 1: Opened the vacuum and inspected –No problem found § Nov. 5: Closed the vacuum to resume operation § Nov. 7: A serious leak occurred and identified –Leak is from the He cooling line of IR Be beam pipe Oct. 29, 2002-Nov. 8, 2002

6. March 21st, 2003Nobu Katayama6 Structure of IP beam pipe for SVD1.4 10  m gold by vacuum sputtering 10~30  m gold by chemical plating 200~230  m gold by chemical plating Inner Surface He Beryllium part is cooled by Helium gas. Aluminum part is cooled by water. :to reduce SR BG to reduce particle background

7. March 21st, 2003Nobu Katayama7 Pictures using optical fiber scope

8. March 21st, 2003Nobu Katayama8 Locating the leak § After dismounting the beam pipe, a leak check was performed to locate the leak point –Leak was confirmed with a bubbling test –Bubbles were seen on the inner gold sputtered surface of Beryllium beam pipe –Leak is not at the joint of Be and Al Leak

9. March 21st, 2003Nobu Katayama9 Cutting Al part of the beam pipe

10. March 21st, 2003Nobu Katayama10 Inner Beryllium beam pipe Direction of Helium gas position of leak

11. March 21st, 2003Nobu Katayama11 Location of the leak

12. March 21st, 2003Nobu Katayama12 Observations § A large amount of a white powder was found on the outer surface of the inner Beryllium cylinder and on those of Al rings –It looks like its following the flow of He gas § We found two types of powders –Color of one powder is clearly white –The other one looks slightly yellow § Thickness of the inner Beryllium cylinder was measured –No significant loss of Beryllium § The beam pipe was used for three months in 1999 –The powder was there then although the amount was much less

13. March 21st, 2003Nobu Katayama13 Photo before re-assembly (1999)

14. March 21st, 2003Nobu Katayama14 Preliminary results of element analysis § White powder –Main components are Be and O –Probably, it is BeO § Yellow powder –Main components are Al and O –Probably, it is Al 2 O 3 and/or Al(OH) 3 § Commonly found are –Carbon –Small amounts of P, K, Ca, S, Cl, Si, Mn, Fe, and Cu were found. § S and Cl are dangerous elements for corrosion of Beryllium § Si, Mn, Fe and Cu are components of Aluminum alloy § But, expert for element analysis says the amounts of S and Cl are small and are consistent with normal metal § No conclusion, yet

15. March 21st, 2003Nobu Katayama15 Cause of corrosion § Corrosion can occur on the Al and Be surfaces –What caused the corrosion is not known yet § Water, Cl or S? § Radiation? § Analysis of circulation gas is in progress § Before the accident, we had not paid attention to corrosion –Dew point had not been monitored in gas circulating system –We have never analyzed impurity of the circulating gas § Currently, to avoid corrosion –Dew point is monitored(~  20  C) –An additional filter has been installed –Fresh Helium gas is added more frequently, to avoid accumulation of impurities (  Most effective)

16. March 21st, 2003Nobu Katayama16 Possible causes of Helium leak § Corrosion is most suspicious § Heat stress caused by the temperature difference between two walls –Resonant HOM heating during machine study –Helium circulation system troubles § Recycled Be pipe from BP#1 –Large stress at machining process (?) § Very high temperature (~300  C) –When gold was spattered and the Be pipe was welded with Aluminum sections § Defect of material (?) § Still being actively investigated

17. March 21st, 2003Nobu Katayama17 SEM photos of Be surface Beryllium is made by sintering, from a powder of 5~40  m Be particles. Some of them are missing

18. March 21st, 2003Nobu Katayama18 History of Beam Pipe and SVD 1999 2000 2001 2002 2003 BP 1 + SVD 1 BP 2 + SVD 1.2 BP 3 + SVD 1.4 BP 2 + SVD 1.6 Summer 2003 BP 4 + SVD 2! BP3 reused BP1 Be pipe SVD 1.4 electronics can survive up to 2M rad SVD 1 damaged by back scattered synchrotron Rad Dead wafers replaced

19. March 21st, 2003Nobu Katayama19 BP#3(1)BP#2BP#4 cooling for BeHe Paraffin Au on Be 10  m inside20  m outside10  m inside fwd/bwdAluminum Tantalum Au in fwd 200  m inside20  m inside no Au in bwd 20  m inside no Res. HOM5 buckets No? Saw toothbwdnobwd Material (IP)0.6% X 0 0.9% X 0 0.7% X 0 Particle maskstandardtolerable?better Much better BP4!

20. March 21st, 2003Nobu Katayama20 Daily Luminosity 2002/9  2003/3/8 Current limit 2.4A Old beam pipe re-installed Current limit 2.2A

21. March 21st, 2003Nobu Katayama21 Short term plan § 3/24~26: Belle general meeting –Will discuss beam current limit. –LER+HER<2.6A till May? –HER 1A + LER 1.55 A is the max. in last Oct. § Keep running till end of June –Hope to get >150 fb  1 in total –Increase LER current to 2A, then 2.6A and see what happens § This summer –Install SVD2 –Add last two ARES RF cavities so that HER current can reach 1.2A § Operation will start from mid October

22. March 21st, 2003Nobu Katayama22 SVD 1  SVD 2 6+12+18+18= 54 ladders 8+10+14= 32 ladders SVD1SVD2 R BP 1.5 cm R BP 2.0cm R L1 3.0cm R L1 2.0cm R out 6.0cm R out 8.8cm

23. March 21st, 2003Nobu Katayama23 SVD 1.6SVD2.0 R BP / R L1 / R out 20/30/60 mm15/20/90 mm Acceptance 23º<  <139º17º<  <150º # of layer/# of ladders3 / 324 / 54 Max. length (mm)220460 Orthogonal readoutBuilt in double metal layer Flexible printed circuit Isolation of detector bias Integrated capacitor on DSSD Optical isolator in a buffer circuit Fast triggerNoYes Shaping time ~1  s~0.5  s  z (90deg.,p=2GeV/c) ~35  m~25  m Measured Signal to Noise ratio ~2025(lyr4)~36(lyr1) Radiation tolerance~2Mrad~20Mrad How much improved?

24. March 21st, 2003Nobu Katayama24 Beam pipe for SVD2 Smaller radius (1.5cm) Better cooling with liquid Heavier masks Better mechanical structures

25. March 21st, 2003Nobu Katayama25 Forward Backward L#1 L#3 L#4 L#2 DSSD hybridflex DSSDDSSD Ladder construction

26. March 21st, 2003Nobu Katayama26 Ladder mount completed on 13-Feb. 2003. The last of the 54 ladders!

27. March 21st, 2003Nobu Katayama27 Track reconstructed!Shibata

28. Recent physics results Just flashing… Vub B  K B  K*,  K

29. March 21st, 2003Nobu Katayama29 Fully reconstructed B mesons

30. March 21st, 2003Nobu Katayama30 V cb measurement with tag

31. March 21st, 2003Nobu Katayama31 V ub measurements

32. March 21st, 2003Nobu Katayama32 Separating two B’s

33. March 21st, 2003Nobu Katayama33 Two inclusive V ub measurements § § Two new tagging methods –Simulated annealing –D*l reconstruction § § Can measure M x distribution

34. March 21st, 2003Nobu Katayama34 First observation of  § § Br(  )=(2.6+1.1  0.90.3)10  6 –M  < 2.85 GeV/c2 to exclude  c § § Only penguin (b  sssss) can contribute § § Asymmetry in this decay mode is sensitive to NP due to interference with   c K,  c 

35. March 21st, 2003Nobu Katayama35 B  K* angular analysis

36. March 21st, 2003Nobu Katayama36 Projected angular distributions

37. We have just started! More and more Bs  Super KEKB

38. March 21st, 2003Nobu Katayama38 Mission 1: 300 fb  1 Precision test of KM unitarity Search for new physics in B and  decays Identify SUSY breaking mechanism Bread’nd butter for B factories See quantum effect in penguin and box loop Very important if New physics = SUSY Mission 2: 3,000 fb  1 Mission 3: 30,000 fb  1 Mission of Super B Factory(ies)

39. March 21st, 2003Nobu Katayama39 In which processes can we find New Physics? § Rare decays –B  X s ,  –B  K*  § CP violations –B   K S and  ’K S –B  X s  、  § b  c emitting charged Higgs § Forbidden decays by SM § Forbidden/rare decays of 

40. March 21st, 2003Nobu Katayama40 CPV in penguin decays Belle (July 2002) A CP (  K S )=  0.73±0.64 A CP (  ’K S )=  0.76±0.36 A CP (J/  K S )=  0.719±0.074 Expected errors in A CP ’s A CP (  K S,  ’K S )=A CP (J/  K S ) In SM, New phase in penguin loop may change this relation KEKB PEP-II Next B factory

41. March 21st, 2003Nobu Katayama41 Atmospheric Neutrinos Can Make Beauty Strange? § R. Harnik, D. Larson, H. Murayama and A. Pierce (hep-ph/0212180), D. Chang, A. Masiero and H. Murayama (hep-ph/0205111) § Leptogenesis models inspired by the naïve SO(10) unification exist where the near-maximal mixture of  and  results in large mixing of RH super-b and super-s, giving O(1) effects on b  s transitions such as –Asymmetry in B   K s (effect is in first order) –B s mixing –b  s  (effect is of the order of |C g (NP)| 2 )

42. March 21st, 2003Nobu Katayama42 Dominant Right-Right Mixing case

43. March 21st, 2003Nobu Katayama43 SUSY effect in B  K*  § § These measurements are excellent probe to search for SUSY § § Inclusive decay, b  sll, is much less model dependent. An e + e  B factory provides a unique opportunity to measure this by pseudo reconstruction technique A.Ali m(  ) 2 distribution F/B asymmetry SM SUSY models with various parameters set

44. March 21st, 2003Nobu Katayama44 Rare decays of 

45. March 21st, 2003Nobu Katayama45 Charged Higgs in tree decay B  D (*)  vs  D    - Large branching fraction: ~1% - Uncertainty in form factor cancels in the ratio  (B g D  )/  (B g D  ). -  polarization is more sensitive to H ±. M.Tanaka

46. March 21st, 2003Nobu Katayama46 Comparison with an LHC experiment  (B  D  )/  (B  D  ) at B factory with 5,000 fb -1 B factories don’t really do tree diagrams of new particles with the exception of charged Higgs…

47. March 21st, 2003Nobu Katayama47 KEKB upgrade strategy Present KEKB L=10 34 2002030405080706091011 L=10 35 L~10 36  dt =500fb  1 One year shutdown to: replace vacuum chambers double RF power upgrade inj. linac g C-band larger beam current smaller  y * long bunch option crab crossing I LER =1.5A  2.6A I LER =9.4A I LER =20A Constraint: 8GeV x 3.5GeV wall plug pwr.<100MW crossing angle<30mrad  dt =3000fb  1 before LHC!!

48. March 21st, 2003Nobu Katayama48 Detector upgrade § Higher luminosity collider will lead to: –Higher background § radiation damage and occupancy in the vtx. detector § fake hits in the EM calorimeter § radiation problem in the tracker and KL  detector –Higher event rate § higher rate trigger, DAQ and computing § Require special features to the detector –low p  identification for s  reconstruction eff. –hermeticity for “reconstruction”

49. March 21st, 2003Nobu Katayama49  / K L detection 14/15 lyr. RPC+Fe Tracking + dE/dx small cell + He/C 2 H 5 CsI(Tl) 16X 0 Aerogel Cherenkov counter + TOF counter Si vtx. det. 3 lyr. DSSD SC solenoid1.5T 8GeV e  3.5GeV e  Detector upgrade: an example  2 pixel lyrs. + 3 lyr. DSSD  tile scintillator  pure CsI (endcap)  remove inner lyrs.  “TOP” + RICH New readout and computing systems

50. March 21st, 2003Nobu Katayama50 SVD occupancy and CDC hit rate § Current most inner layer of SVD’s occupancy is 3~5% § Current most inner layer of CDC’s occupancy is 2~3% § With 10 35 luminosity, two layers of pixel + silicon (~15cm R) + CDC survives § With 10 36 luminosity, Pixel + Silicon a la super BaBar design? Radius = 15cm Cathode Inner Main

51. March 21st, 2003Nobu Katayama51 Does CDC work with L>10 35 ? § § Smaller cell § § Faster gas § § Larger starting diameter Yes !!

52. March 21st, 2003Nobu Katayama52 Small Cell Chamber (with SVD2) ~20cm

53. March 21st, 2003Nobu Katayama53 XT curve for small cell measured Small cell Normal cell

54. March 21st, 2003Nobu Katayama54 New 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

55. March 21st, 2003Nobu Katayama55 Time of propagation (TOP) counter 20mm time & X sensitive PMTs Fused silica(n=1.47) Reflection mirror 200mm A few meters photon hits

56. March 21st, 2003Nobu Katayama56 Aerogel RICH for endcap § Single event display § Hit distribution

57. Super KEKB Accelerator upgrades

58. March 21st, 2003Nobu Katayama58 What’s impressive about KEKB § KEKB and PEP-II have achieved the highest luminosities in history of particle accelerator/collider § KEK and PEP-II have recorded more than 100 fb  1 of data and continue to accumulate Thanks to tremendous efforts by and ingenuity of the commissioning and operation groups

59. March 21st, 2003Nobu Katayama59 Features of KEKB § Super conducting RF cavities and ARES cavities –Holds more than 1A of beam current with SRF § IR region –3  m  100  m: the smallest beam size among the storage rings –Finite crossing angle § Solenoids for positron ring –Suppress photo-electron clouds § Flexible Optics –Real time monitor and correction system

60. March 21st, 2003Nobu Katayama60 Challenges with Super KEKB § High beam currents (LER 9.4A+HER4.1A) –Heating, breakdown will occur –Ultra high vacuum, beam lifetimes –Power consumption (80~100MW) –Stability of the beam/photo electron clouds –Injection –Noise/Background to detector § Beam-beam effect (tune shift of 0.05 assumed for 10 35 ) –Beam-beam tune shift; unknown –For a double ring machine, more than 50 parameters must be optimized simultaneously –Hard to maintain the optimum beam conditions due to disturbances § Optics with very small focusing depth (3mm) –KEKB vertical beta is <6mm (world record) –Shorter bunch length:=more peak current gives more power dissipation, shorter lifetime

61. March 21st, 2003Nobu Katayama61 Towards Super KEKB § LER 9.4A + HER 4.1A (4~6 times as now) –Rewind solenoids –Double RF systems –Replace vacuum chambers of the both rungs –Cooling system § More focusing and shorter bunch (half as now) –New IR § Charge switch and better/faster injection –8GeV positron injection with a C-band linac –Damping ring –New positron production target § Crab crossing

62. March 21st, 2003Nobu Katayama62 Machine parameters Energy : 3.1/9 GeV Options April 2002 from SBF Luminosity Head-on collision (effective) Need crab cavity S-S, S-W simulation Baseline design of Super KEKB

63. March 21st, 2003Nobu Katayama63 Crab crossing § Recent beam-beam simulation gives  =0.1  0.25 with x ≈ 0.5 Head-on (crab) collision  z=  y=3 mm yielding 0.8~2.0  10 32 luminosity per bunch >>10 35 cm  2 s  1

64. March 21st, 2003Nobu Katayama64 Crab cavity § Crab crossing is powerful scheme to achieve high luminosity § It is hard to develop crab cavity for extremely high beam current § Test of crab crossing at KEKB in 2005~6 –1 crab : 11 mrad/HER  x =200 m –or 2 crabs: for both rinfs Crab cavity Nikko section Magnet reconfiguration

65. March 21st, 2003Nobu Katayama65 (Each building for 4 〜 6 RF units.) D8D7 D4 D10 D11 new D1D2 D5 LER-RF (ARES) HER-RF (ARES) HER-RF (SCC) 5 buildings should be added. 50% more RF cavities Double # of Klystrons #RF/#SRF 30/8  44/12 #Kly/ACPW(MW) 23/45  56/73

66. March 21st, 2003Nobu Katayama66 Energy exchange (HER : e + /LER : e  ) § Advantage : –Effect of photoelectron cloud can be reduced. ■ Positron energy increases. –Injection time can be reduced. ■ Intensity of injector : e - > e + ■ Beam current : e - > e + § Unknown : –Multipactering occurs in e + at HER or not ? ■ Height of vacuum chamber is smaller than LER. –Is fast ion instability safe for e - in LER ? ■ Electron energy decreases. § Major upgrade of injector linac is needed. –Energy upgrade : C-band scheme

67. March 21st, 2003Nobu Katayama67 Linac upgrades for 8 GeV e + 2-Bunches for Simultaneous Injection 1-st bunch -> e- Injection 2-nd bunch -> e+ production S-band accl. units are replaced with C-band units. Accl. Field 21 -> 41 MV/m e+ Damping Ring for lower emittance

68. March 21st, 2003Nobu Katayama68 Summary § Belle and KEKB have resumed operation after the He leak accident –Even with a current limit of less than 2.4A, we have achieved new integrated luminosity records, for example, 462pb  1 /day § We hope to accumulate >150fb  1 by June –Expect to have a lot of physics results § We will install SVD2, two more RF cavities and come back in October § We are hoping to upgrade KEKB and Belle to reach 10 35 luminosity and to accumulate 3000fb  1 before 2010 when LHC starts producing results –Simulation tells us that we may reach 10 36 with head-on collision with crossing angles using the crab cavities