SuperKEKB May 16, 2006 Flavour Physics at the Era of the LHC @CERN Masa Yamauchi KEK
Outline • Introduction • Achievements of the B factories and the next step • SuperKEKB: physics • SuperKEKB: detector and schedule • Situation at KEK and internationalization of the project • Summary
_ r: +0.026 -0.030 0.197 _ h: +0.019 -0.018 0.339 Achievements of the B Factories Quantitative confirmation of the KM theory 475°< f2 < 113° 4|Vub| =(4.35±0.52) 10-3 Vtd f2 4Dmd=0.511ps-1 4|Vtd/Vts|= 0.200±0.046 Vub KM unitarity triangle f3 f1 Vcb 422°<f3<113° 4sin2f1= 0.728±0.061 4|Vcb|=(4.08±0.27)10-2 (Belle, 2005)
Daily integ. luminosity 1fb-1/day Another important achievement • Success of KEKB and PEP-II enabled us to design a new e+e-B factory with much higher Lpeak. Asymmetric e+e- collider with L > 1034
What is next with B physics? • If new physics at O(1)TeV… • It is natural to assume that the effects are seen in B/D/t decays. • Flavour structure of new physics? • CP violation in new physics? • These studies will be useful to identify mechanism of SUSY breaking, if NP=SUSY. • Otherwise… • Search for deviations from SM in flavor physics will be one of the best ways to find new physics.
New physics effect in B decays G.Hiller Likelihood for the effects of new physics to be seen in B decays.
Physics at SuperKEKB New source of CP violation New source of flavor mixing Precision test of KM scheme LFV t decays SUSY breaking mechanism Charm physics Super-high statistics measurements: aS, sin2qW, etc.
Precision test of KM scheme 50 ab-1 If tree-level and bgd mixing processes give inconsistent results, Result with 0.3fb-1 or …indicates something new in
Search for new CP phases In general, new physics contains new sources of flavor mixing and CP violation. 4In SUSY models, for example, SUSY particles contribute to the bs transition, and their CP phases change CPV observed in BfK, h’K etc. SM only 0.2 0.4 ASUSY ASM | | 0.6 0.8 SM SUSY contribution In general, if SUSY is present, the s-quark mixing matrix contains complex phases just as in the Kobayashi-Maskawa matrix. Effect of SUSY phase qSUSY on CPV in BfK decay
A possible hint for NP: b→sqq (Cf= -Af) Naïve average sin2f1eff=0.5 0.09 (2.6s from sin2f1)
Sensitivity to new CP phases Estimated error in the measurement of time dependent CP violation Discovery region with 50 ab-1 |ASUSY/ASM|2 qnew physics
Search for new flavor mixing l + l - : Probe the flavor changing process with the “EW probe”. g, Z0 b quark s quark This measurement is especially sensitive to new physics such as SUSY, heavy Higgs and extra dim. ? Theoretical predictions for l +l - forward-backward charge asymmetry for SM and SUSY model with various parameter sets. Possible observables: • 4Ratio of branching fractions • 4Branching fraction • 4CP asymmetry • 4q 2 distribution • 4Isospin asymmetry • 4Triple product correlation • 4Forward backward asymmetry • 4Forward backward CP asymmetry The F/B asymmetry is a consequence of g-Z0 interference.
Sensitivity to new flavor mixing Experimental result with 0.35 ab-1 Belle, 2005 Sensitivity at Super KEKB Standard model MC, 50 ab-1 4Zero-crossing q2 for AFB will be determined with 5% error with 50ab-1. These patterns were excluded by recent data from Belle.
H+/W+ t+ “B meson beam” technique 95.5%C.L. exclusion boundaries B Belle, 2006 e- e+ Υ B p D full reconstruction 0.2~0.3% for B+ Application H±search in Bgtn 5ab-1 assumed
Charm physics at B factories D0D0 mixing may be observed at B factories with higher L. Belle, 2005, 400fb-1 (0,0) CL 96.1%
~ ~ m(e) ~ c 0 % t BR(tgmg) ~10-6 tan2b ~ 1 TeV (mL2)32 mL2 ( ) 4 mSUSY ~ Search for flavor-violating t decay • SUSY + Seesaw • Flavor violation by n-Yukawa coupling. • Large LFV Br(tmg)=O(10-7~9) t m(e) Expected sensitivity at SuperKEKB Present Belle Super-KEKB Gaugino mass = 200GeV SuperKEKB 10ab-1
Comparison with LHCb LHCb is advantageous in… e+e-is advantageous in… CPV inB→fKS, h’KS,… CPV inB→J/yKS CPV inB→KSp0g Most of B decays not including n or g B→Knn, tn, D(*)tn Time dependent measurements of BS Inclusive b→smm, see t→mg and other LFV B(S,d)→mm D0D0mixing BCand bottomed baryons These are complementary to each other !!
Why∫L dt = 50ab-1 is a goal? • Most of the interesting measurements will be limited by unavoidable systematics when we reach 50ab-1. Obs. dstat with 50ab-1 dsyst with 50ab-1 Theory err. sin2f1 0.004 0.014 ~0.01 f2 1.2º a few º f3 1.2º O(1) º |Vub| 1% ~1% ~5 % SfKs 0.023 0.020 AfKs 0.016 0.018 Sh’Ks 0.013 0.020 Ah’Ks 0.009 0.017 DCPV in b→sg 0.003 0.002 0.003
∫L dt = 50ab-1 • Takes 250 years with present KEKB • 8.3 years with Lpeak=4×1035 :baseline design of SuperKEKB • 3.3 years with Lpeak=1×1036 Great efforts are being made by the machine physicists at KEK.
KEKB Mt. Tsukuba Tsukuba exp. hall KEKB ring Injection Linac
SuperKEKB • Asymmetric energy e+e- collider at ECM=m((4S)) to berealized by upgrading the existing KEKB collider. • Super-high luminosity 41035/cm2/sec 510 9 BB per yr. 410 9t +t - per yr. Belle with improved rate immunity Higher beam current, more RF, smaller by* and crab crossing L = 41035/cm2/sec http://belle.kek.jp/superb/loi
Proposed schedule 10 SuperKEKB ~4×1035 Lpeak~1.5×1034 1.5 - 3×1034 8 6 5BBB and t+t- every year Integrated luminosity (ab-1) 2 yr shutdown for upgrade 4 Crab cavity installation Belle is here. 0.58ab-1 2 0 2000 2002 2004 2006 2008 2010 2012 2014 Calendar year
Super Belle Faster calorimeter with Wave sampling and pure CsI crystal Super 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
Situation at KEK • Next three slides are from the report of “Future vision committee” lead by the previous KEK director, Yoji Totsuka, given to the new director, Atsuto Suzuki, WITHOUT giving any constraint to the new management.
PF upgrade PF Budget transfer ERL prototype ERL construction experiment 2006 2008 2010 2012 2014 2016 2018 2020 KEKB ILC R&D Budget transfer Budget transfer ILC construction experiment J-PARC n, n construction J-PARC n, K experiment J-PARC n, m experiment Budget transfer J-PARC R&D upgrade Scenario Version 1 By previous KEK management
PF upgrade PF Budget transfer ERL prototype ERL construction experiment 2006 2008 2010 2012 2014 2016 2018 2020 KEKB KEKB upgrade experiment ILC R&D Budget transfer ILC construction experiment J-PARC n, n construction J-PARC n, K experiment J-PARC n, m experiment Budget transfer upgrade experiment J-PARC R&D Scenario Version 2 By previous KEK management
PF upgrade PF Budget transfer ERL prototype ERL construction experiment 2006 2008 2010 2012 2014 2016 2018 2020 KEKB KEKB upgrade experiment ILC R&D ILC construction experiment J-PARC n, n construction J-PARC n, K experiment J-PARC n, m experiment Budget transfer J-PARC R&D upgrade experiment Scenario Version 3 By previous KEK management
LCPAC recommendation • LCPAC is a KEK’s advisory panel that gives recommendation on the e+e- collider program at KEK. • 2005 report says; The main objective of SuperBelle is to elucidate the flavor structure of anticipated new physics at or beyond the TeV scale. We find the presented scientific goal exciting. The Committee recommends to continue the accelerator and the detector R&D so that SuperKEKB can be proposed for construction when the time is ripe.
Internationalization • “KEK + in-kind contribution from others” is a favorable scenario. • KEK cannot afford to pay for all, because it will also support J-PARC and ILC R&D. • Better chance to get early approval by the Japanese Government. • We are open to any proposal. • A possible way: form an international steering group of Super B factory without having a specific site or technology selected. • Have both SuperKEKB and Linear Super B (and others, if any) in the scope. • Make Super B factory more popular in the world-wide HEP community. • Submit joint proposals to the possible host labs.
Summary • KEKB/Belle has been running very successfully, and brought important scientific achievements together with BaBar. • Next generation e+e-B factory with L>>1035 will be very useful to study the new sources of flavor mixing and CP violation. • SuperKEKB upgrade has been proposed • Internationalization will be necessary for any Super B Factory to be realized. • Why? – Search for new sources of flavor mixing and CP violation • How? – Increase NB, decrease by*, and crab crossing: L=41035/cm2/s • What? – New beam pipe, crab cavity, new injector with damping ring. Belle will also be upgraded assuming DC is usable. • Who? – KEKB/Belle is ready to serve as a core of the project, but it is open. • Where? – Upgrade existing KEKB. • When? – JFY2009 and 2010 • How much? – up to US$400M, depending on what to be upgraded.