Super KEKB project WIN03 Oct 9 th, 2003 Nobu Katayama KEK

Octl 9th, 2003Nobu Katayama2 Outline § Belle/KEKB status § Super KEKB plan –Physics –Detector study –Accelerator study

Octl 9th, 2003Nobu Katayama3 KEKB status 1999/10  2003/7/1 > 50 fb  1 in years 2002, 2003 LER~1.55A HER~1.1A With SRF  cm -2 s fb -1

Octl 9th, 2003Nobu Katayama4 Best day (May 12 th, 2003) pb -1 /day recorded

Octl 9th, 2003Nobu Katayama5 SVD 1  SVD = 54 ladders = 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

Octl 9th, 2003Nobu Katayama6 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) 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?

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

Octl 9th, 2003Nobu Katayama8 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)

Octl 9th, 2003Nobu Katayama9 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 

Octl 9th, 2003Nobu Katayama10 CPV in penguin decays Belle (August 2003) A CP (  K S )=  0.96±0.50 A CP (  ’K S )=  0.43±0.27 A CP (J/  K S )=  0.731±0.057 Prove 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 5  discovery KSK+K-KS’KSKSK+K-KS’KS  A CP

Octl 9th, 2003Nobu Katayama11 Atmospheric Neutrinos Can Make Beauty Strange? § 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 ) § Ref. R. Harnik, D. Larson, H. Murayama and A. Pierce (hep-ph/ ), D. Chang, A. Masiero and H. Murayama (hep-ph/ ) § Many other GUT inspired models are coming up!

Octl 9th, 2003Nobu Katayama12 Dominant Right-Right Mixing case

Octl 9th, 2003Nobu Katayama13 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

Octl 9th, 2003Nobu Katayama14 Rare decays of 

Octl 9th, 2003Nobu Katayama15 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

Octl 9th, 2003Nobu Katayama16 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… But together with LHC measurements, we can determine tan  !

Octl 9th, 2003Nobu Katayama17 What can we do? Compilation at the 5 th High Luminosity WS

Octl 9th, 2003Nobu Katayama18 KEKB upgrade strategy Present KEKB L= 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!!

Octl 9th, 2003Nobu Katayama19 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”

Octl 9th, 2003Nobu Katayama20  / 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

Octl 9th, 2003Nobu Katayama21 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 luminosity, two layers of pixel + silicon (~15cm R) + CDC survives § With luminosity, Pixel + Silicon a la super BaBar design? Radius = 15cm Cathode Inner Main

Octl 9th, 2003Nobu Katayama22 Does CDC work with L>10 35 ? § § Smaller cell § § Faster gas § § Larger starting diameter Yes !!

Octl 9th, 2003Nobu Katayama23 Small Cell Chamber (with SVD2) ~20cm

Octl 9th, 2003Nobu Katayama24 XT curve for small cell measured Small cell Normal cell

Octl 9th, 2003Nobu Katayama25 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

Octl 9th, 2003Nobu Katayama26 Time of propagation (TOP) counter 20mm time & X sensitive PMTs Fused silica(n=1.47) Reflection mirror 200mm A few meters photon hits

Octl 9th, 2003Nobu Katayama27 Aerogel RICH for endcap § Single event display § Hit distribution

Super KEKB Accelerator upgrades

Octl 9th, 2003Nobu Katayama29 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 140 fb  1 of data and continue to accumulate Thanks to tremendous efforts by and ingenuity of the commissioning and operation groups

Octl 9th, 2003Nobu Katayama30 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

Octl 9th, 2003Nobu Katayama31 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 ) –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

Octl 9th, 2003Nobu Katayama32 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

Octl 9th, 2003Nobu Katayama33 Accelerator Upgrades for Super KEKB K. Izu 2003 § Crab cavities § More RF sources § More cavities § Super Belle § New IR § New beam pipe & bellows § Damping ring § Positron source § Charge switch by C-band

Octl 9th, 2003Nobu Katayama34 Machine parameters  x = 20 cm  x = 15 cm

Octl 9th, 2003Nobu Katayama35 Crab cavity developments crossing angle 22 mrad Head-on(crab) ◊ ◊ ◊ ◊ ◊ yy (Strong-weak simulation) (Strong-strong simulation) l Crab crossing may boost the beam-beam parameter up to 0.2! l Superconducting crab cavities are under development, will be installed in KEKB in K. Ohmi K. Hosoyama, et al

Octl 9th, 2003Nobu Katayama36 (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

Octl 9th, 2003Nobu Katayama37 Energy exchange (HER : e + /LER : e  ) § Advantages : –Effect of photoelectron cloud can be reduced. ■ Positron energy increases. –Injection time can be reduced. ■ Intensity of injector : e - > e + ■ Beam current : e - > e + § Unknowns : –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

Octl 9th, 2003Nobu Katayama38 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 Achieved  40 MW (0.5ms, 50pps),  > 40 MV/m (1m structure) Goal: 40 MW 40 MV/m

Octl 9th, 2003Nobu Katayama39 Summary § Belle and KEKB have achieved 1.06×10 34 cm  2 s  1 and 158 fb  1 § We have installed SVD2, two more RF cavities and come back online in 2 wks § We are hoping to upgrade KEKB and Belle to reach luminosity and to accumulate 3000fb  1 before 2010 when LHC starts producing results –Simulation tells us that we may reach 5  with head-on collision with crossing angles using the crab cavities