Status of SuperKEKB May 11, 2007 SuperB Workshop Masa Yamauchi KEK

Conditions for SuperKEKB Physics case Detector design Machine design SuperKEKB Support from domestic/int’l community Funding

Milestones toward approval Japanese HEP community Academy of Science CSTP LoI June 2004 KEK’s decision MEXT MOF Support from the int’l HEP community Review panel Review committee

Consensus in J-HEP community Japanese HEP community reached the following agreement in October 2006 after a long discussion. First priority is to realize ILC, and its R&D should be boosted. On the other hand, flavour physics programs (SuperKEKB, and K and n program at J-PARC) should be carried out as physics programs before ILC (i.e., 2010’s).

Recommendation by Belle-PAC The committee provided strong endorsement to SuperKEKB in the meeting in 2007. This is also an important support from the int’l community.

J-PARC n, n construction 2006 2008 2010 2012 2014 2016 2018 2020 J-PARC n, n construction J-PARC R&D J-PARC n, K experiment J-PARC n, m experiment upgrade Budget transfer PF upgrade PF Budget transfer ERL prototype ERL construction experiment KEKB ILC R&D ILC construction experiment Budget transfer Option 1 KEKB ILC R&D ILC construction experiment KEKB upgrade Budget transfer Option 1’

J-PARC = Japan Proton Accelerator Research Complex J - PARC ( Tokai ) J-PARC = Japan Proton Accelerator Research Complex Hadron Beam Facility Materials and Life Science Experimental Facility 50 GeV Synchrotron (0.75 MW) Neutrino to Super-Kamiokande 3 GeV Synchrotron (25 Hz, 1MW) Linac (330m) Joint Project between KEK and JAEA

Joint effort with European SuperB Common assumption: there will be at most one Super B Factory built in the world. It is implicitly assumed that Western and Eastern SuperB’s will be merged into a single project in some future. We now have four options: (high current or low beta) x (KEK or Rome) None of the options should be thrown away at this point. Close communication is going on. Frequent visits and telephone meetings to exchange status report and ideas Joint meeting in Paris (i.e., this meeting), where support letter will be signed. Third joint workshop to be scheduled sometime in fall 2007(?). Joint detector R&D program will be arranged.

Detector issue: background x20 Bkg KEKB SuperB Luminosity (1034cm-2sec-1) 1.7 80 HER curr. (A) LER curr. (A) vacuum (10-7Pa) 1.2 1.6 ~1.5 4.1 9.4 5 Bkg increase - x 20 TRG rate (kHz) phys. origin Bkg origin 0.4 0.2 14 10 4 x10 Bkg KEKB Bkg SVD CDC PID / ECL KLM Shynchrotoron radiation Beam-gas scattering (inc. intra-beam scattering) Radiative Bhabha

Super Belle Faster calorimeter with Wave sampling and pure CsI crystal Particle identifier with precise Cherenkov device KL/m detection with scintillator and new generation photon sensors Background tolerant super small cell tracking detector New Dead time free readout and high speed computing systems Si vertex detector with high background tolerance

Summary 2008 will be a critical timing for KEKB/SuperKEKB. J-PARC construction will be completed. Belle accumulates 1000/fb. PEP-II/BaBar will be shutdown. It is likely that KEK takes some decision soon. Machine: KEK + contributions from the world Detector: perfectly open to the new collaboration Hope to strengthen collaboration with Western SuperB.