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Status of Belle Super KEKB plan

Status of Belle Super KEKB plan

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Status of Belle Super KEKB plan

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

  2. Outline • Belle/KEKB status • General • Beam pipe accident • SVD2 • Recent physics results • Super KEKB plan • Physics • Detector study • Accelerator study Nobu Katayama

  3. KEKB status1999/10-2003/3/18 IP leak: Longest unscheduled shutdown Oct.30~Dec 2002 > 50 fb-1 in a year 2002 LER>1.55A HER>1A with SRF >50 fb-1 in 2002 Nobu Katayama

  4. Best day (03/17/2003)462pb-1/day recorded NK on shift! Nobu Katayama

  5. Beam pipe accident Oct. 29, 2002-Nov. 8, 2002 • 6AM, Oct. 29, 2003:New record:8.261033 • 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 Nobu Katayama

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

  7. Pictures using optical fiber scope Nobu Katayama

  8. 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 Nobu Katayama

  9. Cutting Al part of the beam pipe Nobu Katayama

  10. Inner Beryllium beam pipe Direction of Helium gas position of leak Nobu Katayama

  11. Location of the leak Nobu Katayama

  12. 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 Nobu Katayama

  13. Photo before re-assembly (1999) Nobu Katayama

  14. 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 Al2O3 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 Nobu Katayama

  15. 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) Nobu Katayama

  16. 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 Nobu Katayama

  17. SEM photos of Be surface Beryllium is made by sintering, from a powder of 5~40mm Be particles. Some of them are missing Nobu Katayama

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

  19. Much better BP4! Nobu Katayama

  20. Daily Luminosity2002/9-2003/3/8 Current limit 2.4A Current limit 2.2A Old beam pipe re-installed Nobu Katayama

  21. 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 Nobu Katayama

  22. SVD 1  SVD 2 RBP 1.5 cm RBP 2.0cm RL1 2.0cm RL1 3.0cm Rout 8.8cm Rout 6.0cm 8+10+14= 32 ladders 6+12+18+18= 54 ladders SVD1 SVD2 Nobu Katayama

  23. How much improved? Nobu Katayama

  24. Beam pipe for SVD2 Smaller radius (1.5cm) Better cooling with liquid Heavier masks Better mechanical structures Nobu Katayama

  25. Ladder construction Backward Forward L#1 L#2 L#3 L#4 hybrid flex DSSD DSSD DSSD Nobu Katayama

  26. Ladder mount completed on 13-Feb. 2003. The last of the 54 ladders! Nobu Katayama

  27. Track reconstructed! Shibata Nobu Katayama

  28. Recent physics results Vub BffK BffK*, fK Just flashing…

  29. Fully reconstructed B mesons Nobu Katayama

  30. Vcb measurement with tag Nobu Katayama

  31. Vub measurements Nobu Katayama

  32. Separating two B’s Nobu Katayama

  33. Two inclusive Vub measurements • Two new tagging methods • Simulated annealing • D*ln reconstruction • Can measure Mx distribution Nobu Katayama

  34. First observation of BffK • Br(BffK)=(2.6+1.1-0.90.3)10-6 • Mff < 2.85 GeV/c2 to exclude hc • Only penguin (b  sssss) can contribute • Asymmetry in this decay mode is sensitive to NP due to interference with BhcK, hc ff Nobu Katayama

  35. BfK* angular analysis Nobu Katayama

  36. Projected angular distributions Nobu Katayama

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

  38. Mission of Super B Factory(ies) Bread’nd butter for B factories Mission 1: 300 fb-1 Precision test of KM unitarity See quantum effect in penguin and box loop Mission 2: 3,000 fb-1 Search for new physics in B and t decays Mission 3: 30,000 fb-1 Identify SUSY breaking mechanism Very important if New physics = SUSY Nobu Katayama

  39. In which processes can we find New Physics? • Rare decays • B  Xsg ,rg • B  K*mm • CP violations • B fKSandh’KS • B  Xsg 、rg • b c emitting charged Higgs • Forbidden decays by SM • Forbidden/rare decays of t Nobu Katayama

  40. 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 2002) ACP(fKS)=-0.73±0.64 ACP(h’KS)=+0.76±0.36 KEKB PEP-II Next B factory ACP(J/yKS)=+0.719±0.074 Nobu Katayama

  41. 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 nt and nm results in large mixing of RH super-b and super-s, giving O(1) effects on bs transitions such as • Asymmetry in B fKs (effect is in first order) • Bs mixing • b  sg (effect is of the order of |Cg(NP)|2) Nobu Katayama

  42. Dominant Right-Right Mixing case Nobu Katayama

  43. SUSY effect in BK*mm F/B asymmetry m(mm)2 distribution A.Ali SUSY models with various parameters set SM • 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 Nobu Katayama

  44. Rare decays of t Nobu Katayama

  45. Charged Higgs in tree decay • Large branching fraction: ~1% • Uncertainty in form factor cancels • in the ratio G(BgDtn)/G(BgDmn). • t polarization is more sensitive to H±. BD(*)tn vs. D(*)mn M.Tanaka +/- Nobu Katayama

  46. Comparison with an LHC experiment G(BDtn)/G(BDmn) 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… Nobu Katayama

  47. KEKB upgrade strategy larger beam current smaller by* long bunch option crab crossing L~1036 ILER=20A Constraint: 8GeV x 3.5GeV wall plug pwr.<100MW crossing angle<30mrad dt =3000fb-1 L=1035 before LHC!! ILER=9.4A One year shutdown to: replace vacuum chambers double RF power upgrade inj. linac g C-band Present KEKB L=1034 ILER=1.5A2.6A dt =500fb-1 2002 03 04 05 06 07 08 09 10 11 Nobu Katayama

  48. 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 KLm detector • Higher event rate • higher rate trigger, DAQ and computing • Require special features to the detector • low pm identification for smm reconstruction eff. • hermeticity for n “reconstruction” Nobu Katayama

  49. Detector upgrade: an example Aerogel Cherenkov counter + TOF counter SC solenoid1.5T “TOP” + RICH 3.5GeV e+ CsI(Tl) 16X0  pure CsI (endcap) 8GeV e- Tracking + dE/dx small cell + He/C2H5  remove inner lyrs. New readout and computing systems Si vtx. det. 3 lyr. DSSD m / KL detection 14/15 lyr. RPC+Fe  2 pixel lyrs. + 3 lyr. DSSD  tile scintillator Nobu Katayama

  50. 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 1035 luminosity, two layers of pixel + silicon (~15cm R) + CDC survives • With 1036 luminosity, Pixel + Silicon a la super BaBar design? Cathode Inner Main Radius = 15cm Nobu Katayama