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					Future B Physics Program
         at KEK
   (KEKB upgrade strategy)
       - KEK’s Roadmap -



             BNM 2008 (24-Jan, Atami)
               Y.Sakai, KEK
               based on slides by
                 Masa Yamauchi, KEK
                                        1
Outline


Introduction: KEKB and Belle
Next program of quark flavour physics
KEK’s five year roadmap
KEKB upgrade plan → Onishi’s talk
Detector issues
Organization of new experimental group
Summary

                                          2
KEKB and Belle




                 3
                          Belle Detector
                                         Cherenkov detector
                                         n=1.015~1.030
     SC solenoid
     1.5T
                                             3.5GeV e+
 EM calorimeter
 (CsI(Tl))

TOF counter
 8GeV e-
                                             Central drift chamber
                                             He(50%)+C2H6(50%)




                                        m / KL detector
                   Si vertex detector
                                                               4
              The Belle Collaboration
                                                    Nagoya U.              Seoul National U.
BINP                  IHEP, Vienna
                                                    Nara Women’s U.        Shinshu U.
Chiba U.              ITEP
                                                    National Central U.    Sungkyunkwan U.
U. of Cincinnati      Kanagawa U.
                                                    National Taiwan U.     U. of Sydney
Ewha Womans U.        KEK
                                                    National United U.     Tata Institute
Fu-Jen Catholic U.    Korea U.
                                                    Nihon Dental College   Toho U.
U. of Giessen         Krakow Inst. of Nucl. Phys.
                                                    Niigata U.             Tohoku U.
Gyeongsang Nat’l U.   Kyoto U.
                                                    Nova Gorica            Tohuku Gakuin U.
Hanyang U.            Kyungpook Nat’l U.
                                                    Osaka U.               U. of Tokyo
U. of Hawaii          EPF Lausanne
                                                    Osaka City U.          Tokyo Inst. of Tech.
Hiroshima Tech.       Jozef Stefan Inst. / U. of
                      Ljubljana / U. of Maribor     Panjab U.              Tokyo Metropolitan U.
IHEP, Beijing
                      U. of Melbourne               Peking U.              Tokyo U. of Agri. and Tech.
IHEP, Moscow
                                                    Princeton U.           INFN Torino
                                                    Riken                  Toyama Nat’l College
                                                    Saga U.                VPI
                                                    USTC                   Yonsei U.




                           14 countries, 55 institutes, ~400 collaborators
Scientific Achievements of B Factories (1)

        Observation of CPV in the B meson system
                  G(BfCP;t) - G(BfCP;t)
       ACP(t) =                           = Af cosDmt + Sf sinDmt
                  G(BfCP;t) + G(BfCP;t)
                                                Belle, July 05
                                                                 B0J/yKS

                                                                    B0J/yKS
         




                                                Belle, July 05

  Af ~ 0
  Sf = 0.652±0.039±0.020
  Consistent with BaBar’s meas.

                                                                               6
Achievements of the B Factories

          Quantitative confirmation of the KM model

       Belle, July 05
                        B0J/yKS

                           B0J/yKS




Discovery of CP violation in BB system




    Af ~ 0
    Sf = 0.652±0.039±0.020
       Belle, July 05
   Violation of CP symmetry !

                                                      7
Other highlights
                               Many new resonances
                                                                 Evidence for Bgtn
  AFB in       BgK*l+l-


                                    X(3872)
                                              Z(4430)
 Belle, 2005
                      SM




 D0-D0 mixing              Bgdg transition              BgD*tn




                                                                   and more…    8
Another important achievement

           Asymmetric e+e- collider with L > 1034




 Success of KEKB and PEP-II enabled us to design a new
  e+e- B factory with much higher Lpeak.
                                                          9
What is next with flavour 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.


                                                              10
 KEKB upgrade
  Asymmetric energy e+e- collider at ECM=m((4S)) to be
   realized by upgrading the existing KEKB collider.
  Super-high luminosity  21035/cm2/sec  210 9 BB per yr.
                           (1st stage: >x10)        210 9 t+t- per yr.

                                               Belle with improved rate immunity




Higher beam current,
more RF, smaller by* and
crab crossing
  L = 21035/cm2/sec

  final target ~81035/cm2/sec
   (smooth transition: 50 ab-1)                   http://belle.kek.jp/superb/loi
                                                                             11
Physics at upgraded KEKB

   New source of                     New source of
   CP violation                      flavor mixing


                    Precision test
LFV t decays
                    of KM scheme

                                            SUSY breaking
                                            mechanism
 Charm physics
  New resonances,   Super-high statistics
  D0D0 mixing…        measurements:
                        aS, sin2qW, etc.
                                                        12
  SUSY flavour physics: mass matrix of squark and slepton will be determined
  by their direct production at the energy frontier and flavour physics measurements.

                                                             Quark flavor changing
                                                             processes



                                            Off-diagonal
            Diagonal

LHC/ILC
SUSY mass spectrum




                                                              Lepton flavor violation




                                                                                  13
                                                                 Y.Okada, Nov. 2007
                                         Searches for new sources of
                                         quark mixing and CP violation

                         CP asymmetries of penguin dominated B decays

                                Present upper                      Deviation from SM
                                limits
Deviation from SM




                                                                   New source of CP
                                                                   violation


                           Measurements
                           at upgraded KEKB                         Relevant to
                                                        ( ab-1 )
                                                                    baryogenesis?
                    Reach of present      Reach of upgraded
                    B factories           KEKB                                         14
A possible hint for NP: b→sqq



                                     Theory :
                                      tends to
                                      positive
                                      shifts




                      Smaller than bgccs
                      in 7 of 9 modes


                                           15
                     Precise measurements of t decays

                                       LFV violating t decay?


                              Upper limits
Branching Fraction




                                                                                                  t->mg




                                                                New Physics predictions
                                                                                                       m->eg


                                                                                          t->eg



                                              Integ. Lum.( ab-1 )                                 T.Goto et al., 2007
                     Reach of B factories                                                                     16
                                            Upgraded KEKB
                 B decays with more than one n
                  Interactions of H±                                          B
                         mb tan b + mu cot b
                                          mt tan b   n    e-          Υ           e+
                         b
Bgtn decays          B
                                                                          B
                         u       H+/W+                                                        p
   Belle, 2006                                       t+
                                                                                     D
   400fb-1
                                                               full reconstruction
                                                                 0.2~0.3% for B+
                                        10ab-1

                                                          Provides a unique method to
                                                          measure b-H±-u and
                                                          b-H±-c coupling strength.
Search region with
Bgtn decays
                                                                                         17
B decays into invisible particles?

          Light dark matter?
            _
B  K(*)nn [or cc]
                               Heavy darm matter is being
                               searched for in direct detection
Model prediction               experiments.




                                Light dark matter can be
                                Searched for in the upgraded
                                KEKB.




                                                          18
                                    Search for right handed interaction

                                             Left-right summetry in new physics?
                               CP violation in B  KSp 0g
Precision of the measurement




                                                                 Sizable CP asymmetry is expected
                                       Present exp. precision
                                                                 in B0Xg decay, if right-handed
                                                                 interaction exists in new physics.




                                                                          U-KEKB

                                  Reach of
                                  upgradedKEKB              SM




                                                                                                      19
                                                                                             T.Goto et al., 2007
                          New resonances
New resonances found at Belle/BaBar

                      Y(4660) Z(4430)          More than 10 new resonances
                      Y(4008)                  have been found at B factories

                    DsJ(2860)
                    DsJ(2700)                  Among them X(3872) and
                    Xcx(3090)
                                               Z(4430) are considered to be
                                    Y(4320)
                                               “exotic” states.
                                       cc2’
       X(3940), Y(3940)
                                 Y(4260)
           Sc* baryon
                triplet
                                X(3872)
  D0*0 & D1*0             DsJ(2317/2460)      More and more exotic states will be
                      hc’ & e+e-cccc         Observed by the upgraded KEKB.

                                                                           20
Identification of SUSY breaking scenario

                     Pattern of deviations from the Standard Model            Y.Okada
           Observ-    Bd-         e       D m(Bs)    B->fKs   B->Msg     b->sg
           ables
  SUSY                unitarity                               indirect CP direct CP
  models

  mSUGRA
                          -           -      -          -         -          +
  SU(5)SUSY
  GUT + nR                -           +      +          -        +           -
  (degenerate)

  SU(5)SUSY
  GUT + nR                -           -      +         ++       ++           +
  (non-
  degenerate)

  U(2) Flavor
  symmetry
                         +            +      +         ++       ++          ++
                                                 ++: Large, +: sizable, -: small
                                                                              21
Strong competitors




                     22
Comparison with LHCb

  e+e- is advantageous in…    LHCb is advantageous in…

 CPV in B→fKS, h’KS,…          CPV in B→J/yKS
 CPV in B→KSp0g                Most of B decays not
  B→Knn, tn, D(*)tn                including n or g

 Inclusive b→smm, see          Time dependent
                                 measurements of BS
  t→mg and other LFV
                               B(s,d)→mm
  D0D0 mixing
                               Bc and bottomed baryons

       These are complementary to each other !!
                                                         23
                                  Roadmap -HEP-
Energy Frontier
ILC R&D                      Construction       Experiment
LHC

Flavor Physics at Luminosity/Intensity Frontier
n, K, m,... at J-PARC
b, c, t,... with upgraded- KEKB/Belle


• According to the JAHEP community’s master plan,
      – Highest priority is given to ILC
      – Before ILC, promote flavor physics at KEKB and J-PARC
• Action before the ILC approval
      – ILC R&D
      – Completion/commissioning of J-PARC
           • Considering the world competition,
             it is urgent to improve neutrino intensity
      – Continuation of KEKB/Belle with upgrade                 24
                KEK Web page

(5 Year Plan)




                               25
26
KEK Roadmap : KEKB
First 3 years: shutdown
   • Replace beam pipe (with ante-chamber)
   • Upgrade interaction region            fundamental
   • Upgrade ground level RF facility      part
   • Improve crab cavities
Last 2 years: operation & improvements
    • Installation of Damping Ring
    • Installation of additional RF
    • Reinforcement of cooling facility     Onishi’s talk

 1st goal: 2 x 1035cm-2sec-1
 smooth transition feasible to 8 x 1035cm-2sec-1(50ab-1)

                                                             27
KEK Roadmap: Belle Upgrade
   in 3 years shutdown
Issues
4 Higher background ( 20)
   - radiation damage and occupancy
   - fake hits and pile-up noise in the EM
4 Higher event rate ( 10)
   - higher rate trigger, DAQ and computing
4 Require special features
   - low p m identification f smm recon. eff.
   - hermeticity f n “reconstruction”

Possible solution:
4Replace inner layers of the vertex detector
  with a silicon striplet detector.
4Replace inner part of the central tracker
  with a silicon strip detector.
4Better particle identification device
4Replace endcap calorimeter by pure CsI.
4Faster readout electronics and computing
  system.
                                                28
   Belle detector upgrade
                      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
New Dead time free                                 tracking detector

  readout and
                              Si vertex detector with
   high speed                    high background         New ideas are
computing systems                    tolerance
                                                           welcomed !
New experimental group
 It will be practical to build new detector by upgrading
  existing Belle.

 However, the experimental group will be a new group, not
  an extension of the present Belle collaboration.

 New participants are all welcomed and have equal
  opportunities to work on detector construction and physics.

 It is welcomed to join the new group, but not Belle.

 Interim Steering Committee is being formed. First meeting
  is scheduled March 2008, inviting potential new
  collaborators.
2007                2008                              2009                             2010                           2011                      2012
 10    1        4        7       10       1       4       7       10       1       4       7       10    1        4        7       10       1       4


 Experiment at KEKB                                                             KEKB/Belle upgrade

                                                              TDR

                Detector                                  Final detector
                Study Report                              design
                (March 08)                                (April 09)


      2007                                                             2008                                                                 2009
  10       11       12       1        2       3       4       5        6       7       8       9    10       11       12       1        2       3       4

                                                          Detector proposals                                           Internal review


                        BNM      Pre kick-off                                  Kick-off
                    (January 08) meeting                                       meeting
                                 (19,20 March 08)                              (3,4 July 08)
                                                                                                         Meeting plan

                Actions to invite new collaborators                                                          One-day general meeting and
                                                                                                             an IB meeting at every BGM
                                                                                                                                     31
Summary
 KEKB/Belle and PEP-II/BaBar have been running very
  successfully, and brought important scientific and technical
  achievements.
 Next generation e+e- B factory with L~1036 will be very
  useful to study the new sources of flavor mixing and CP
  violation.
    –   Search for new CPV in bgs transition
    –   Very precise test of CKM scheme
    –   Search for lepton flavor violating t decays
    –   Studies of H± interactions with fermions
    –   Very precise measurements of aS(@10GeV), sin2qW(@10GeV)…
   KEK Roadmap includes KEKB upgrade.
   KEKB machine upgrade plan  Onishi’s talk
   Detector upgrade necessary to improve BKG/rate immunity.
   New collaboration to be formed soon.
                                                                   32
Roadmap: comment
 Our final goal of the integrated luminosity is 50/ab in the new
experiment at the upgraded KEKB.
 However, we did not include the full upgrade of the machine
in the KEK's roadmap, due to the financial constraint in the
lab. We will upgrade the fundamental part of the accelerator
in the first three years, followed by incremental installation of
the RF systems over several years to increase the beam
current and the luminosity. The initial goal, 10/ab, will be
achieved in the five years of operation after resuming the
experiment. It should be noted that the plan up to this point is
included in the KEK's roadmap. Then, considering the results
of this experiment and LHC as well as progress of ILC and
others carefully, we will decide if we propose further
installation of the RF system to achieve the final goal, 50/ab,
in the next five years.
                                                                33
34
Precision test of KM scheme
                              M.Pierini
                              CKM2006




                                  35
Search for new flavor mixing
                    l+
                                 l-   : Probe the flavor changing
                         g, Z0          process with the “EW probe”.
    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
Possible observables:                      various parameter sets.
 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.
                                                                                         36
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 bs
 transition, and their CP phases change CPV observed in BfK, h’K etc.




                                               U-KEKB



      SM             SUSY contribution
In general, if SUSY is present, the s-quark
mixing matrix contains complex phases just
as in the Kobayashi-Maskawa matrix.
                                                             T.Goto et al., 37
                                                                            2007
Background & TRG rate in future

x20 Bkg
                                                                      KEKB SuperB
                                                    Luminosity
                                                                      ~1.7   ~50
                                                    (1034cm-2sec-1)
                                                    HER curr. (A)      1.2   4.1
x10 Bkg
                                                    LER curr. (A)      1.6   9.4
                                                   vacuum (10-7Pa)    ~1.5    5
KEKB                                               Bkg increase         -    x 20
 Bkg                                               TRG rate (kHz)      0.4   14
                                                     phys. origin      0.2    10
     SVD        CDC PID / ECL KLM
                                                      Bkg origin       0.2     4
Shynchrotoron radiation
Beam-gas scattering (inc. intra-beam scattering)
Radiative Bhabha

				
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