Future B Physics Program at KEK December 2007 Masa Yamauchi KEK

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

KEKB and Belle

 / K L detector Central drift chamber He(50%)+C 2 H 6 (50%) EM calorimeter (CsI(Tl)) Cherenkov detector n=1.015~1.030 Si vertex detector TOF counter SC solenoid 1.5T Belle Detector 8GeV e  3.5GeV e 

                  Belle Collaboration       BINP Chiba U. Hanyang U. U. of Cincinnati Ewha Women’s U. Fu-Jen U. Giessen U. Gyeongsang Nat’l U. U. of Hawaii Hiroshima Tech. HEPHY, Vienna IHEP, Protovino IHEP, Beijing INFN, Torino ITEP Kanagawa U. KEK Korea U. Krakow Inst. of Nucl. Phys. Kyoto U. Kyungpook National U. U. of Lausanne Jozef Stefan Inst. U. of Melbourne Nagoya U. Nara Women’s U. National Central U. National United U. National Taiwan U. Nihon Dental College Niigata U. Nova Gorica U. Osaka U. Osaka City U. Panjab U. Peking U. Princeton U. Illinois U. - Riken Saga U. USTC Seoul National U. Shinshu U. Sungkyunkwan U. U. of Sydney Tata Institute Toho U. Tohoku U. Tohuku Gakuin U. U. of Tokyo Tokyo Inst. of Tech. Tokyo Metropolitan U. Tokyo U. of A and T. Toyama Nat’l College U. of Tsukuba VPI Yonsei U. 

Scientific Achievements of B Factories (1) Observation of CPV in the B meson system A CP (t) =  (B  f CP ;t)  (B  f CP ;t)  (B  f CP ;t)  (B  f CP ;t) = A f cos  mt  S f sin  mt A f ~ 0 S f = 0.652±0.039±0.020  Consistent with BaBar’s meas. B 0  J/  K S Belle, July 05

Achievements of the B Factories Quantitative confirmation of the KM model A f ~ 0 S f = 0.652±0.039±0.020 Violation of CP symmetry ! B 0  J/  K S Belle, July 05 Discovery of CP violation in BB system

Other highlights SM Belle, 2005 D 0 -D 0 mixing A FB in B  K*l  l  X(3872) Many new resonances b  d  transition Evidence for B   and more… Z(4430) BD*BD*

Another important achievement Success of KEKB and PEP-II enabled us to design a new e  e  B factory with much higher L peak. Asymmetric e  e  collider with L > 10 34

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/  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.

KEKB upgrade Asymmetric energy e  e  collider at E CM =m(  (4S)) to be realized by upgrading the existing KEKB collider. Super-high luminosity  2  /cm 2 /sec  2  10 9 BB per yr.  2  10 9     per yr. Higher beam current, more RF, smaller  y * and crab crossing  L = 2  /cm 2 /sec Belle with improved rate immunity

Physics at upgraded KEKB New source of CP violation New source of flavor mixing LFV  decays SUSY breaking mechanism Precision test of KM scheme Super-high statistics measurements:  S, sin 2  W, etc. Charm physics New resonances, New resonances, D 0 D 0 mixing… D 0 D 0 mixing…

Precision test of KM scheme M.Pierini CKM2006

Quark flavor changing processes Lepton flavor violation LHC/ILC SUSY mass spectrum Diagonal Off-diagonal SUSY flavour physics: mass matrix of squark and slepton will be determined by their direct production at the energy frontier and flavour physics measurements. Y.Okada, Nov. 2007

Present upper limits Measurements at upgraded KEKB （ ab -1 ） Reach of present B factories Reach of upgraded KEKB Deviation from SM Relevant to baryogenesis? Relevant to baryogenesis? New source of CP violation New source of CP violation CP asymmetries of penguin dominated B decays Searches for new sources of quark mixing and CP violation

Search for new CP phases In general, new physics contains new sources of flavor mixing and CP violation.  In SUSY models, for example, SUSY particles contribute to the b  s transition, and their CP phases change CPV observed in B  K,  ’ K etc. SMSUSY contribution In general, if SUSY is present, the s-quark mixing matrix contains complex phases just as in the Kobayashi-Maskawa matrix. U-KEKB T.Goto et al., 2007

A possible hint for NP: b→sqq Smaller than b  ccs in all of 9 modes Smaller than b  ccs in all of 9 modes Theory : tends to positive shifts Naïve average of all b  s modes sin2  eff = 0.52 ±  deviation from SM Naïve average of all b  s modes sin2  eff = 0.52 ±  deviation from SM

Search for new flavor mixing ? b quarks quark l  l  : Probe the flavor changing process with the “EW probe”. Theoretical predictions for l  l  forward-backward charge asymmetry for SM and SUSY model with various parameter sets. , Z 0 The F/B asymmetry is a consequence of  - Z 0 interference. This measurement is especially sensitive to new physics such as SUSY, heavy Higgs and extra dim.  Ratio of branching fractions  Branching fraction  CP asymmetry  q 2 distribution  Isospin asymmetry  Triple product correlation  Forward backward asymmetry  Forward backward CP asymmetry Possible observables:

Precise measurements of  decays LF violating  decay? Integ. Lum. （ ab -1 ） Reach of B factories Upgraded KEKB Upper limits   ->e   >e  T.Goto et al., 2007

B decays with more than one 10ab -1 B   decays H/WH/W  B Search region with B   decays Provides a unique method to measure b-H ± -u and b-H ± -c coupling strength. Provides a unique method to measure b-H ± -u and b-H ± -c coupling strength. Interactions of H ± Belle, fb -1 Υ ee ee B B  full reconstruction 0.2~0.3% for B + D

B decays into invisible particles? B  K (*)  or  _ Light dark matter can be searched for in the upgraded KEKB. Light dark matter can be searched for in the upgraded KEKB. Heavy dark matter is being searched for in direct detection experiments. Heavy dark matter is being searched for in direct detection experiments. Model prediction Light dark matter?

Search for right handed interaction CP violation in B  K S  0  Precision of the measurement Present exp. precision Reach of upgradedKEKB SM Sizable CP asymmetry is expected in B 0  Xs  decay, if right-handed interaction exists in new physics. Sizable CP asymmetry is expected in B 0  Xs  decay, if right-handed interaction exists in new physics. Left-right summetry in new physics? U-KEKB T.Goto et al., 2007

Identification of SUSY breaking scenario Bd- unitarity    m(Bs)B->  KsB->Ms  indirect CP b->s  direct CP mSUGRA SU(5)SUSY GUT + R (degenerate) SU(5)SUSY GUT + R (non- degenerate) U(2) Flavor symmetry : Large, +: sizable, -: small Observ- ables SUSY models Pattern of deviations from the Standard Model Y.Okada

Strong competitors

Comparison with LHCb e  e  is advantageous in… LHCb is advantageous in… CPV in B→  K S,  ’K S,… CPV in B→K S  0  B→K, , D (*)  Inclusive b→s , see  →  and other LFV D 0 D 0 mixing CPV in B→J  K S Time dependent measurements of B S B c and bottomed baryons Most of B decays not including or  B (s,d) →  These are complementary to each other !!

Roadmap -HEP- 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 Energy Frontier ILC R&D Construction Experiment LHC Flavor Physics at Luminosity/Intensity Frontier, K, ,... at J-PARC b, c, ,... with upgraded- KEKB/Belle

KEK Roadmap KEKB experiment upgrade experiment Compact ERL R&D construction experiment R&D PF experiment Detector R&D J-PARC construction experiment + upgrade ERL R&D construction experiment ILC R&D construction Preliminary

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

Requirements to the detector - low p  identification  s  recon. eff. - hermeticity  “reconstruction” - radiation damage and occupancy - fake hits and pile-up noise in the EM - higher rate trigger, DAQ and computing Issues  Higher background (  20)  Higher event rate (  10)  Require special features Possible solution:  Replace inner layers of the vertex detector with a silicon striplet detector.  Replace inner part of the central tracker with a silicon strip detector.  Better particle identification device  Replace endcap calorimeter by pure CsI.  Faster readout electronics and computing system. Possible solution:  Replace inner layers of the vertex detector with a silicon striplet detector.  Replace inner part of the central tracker with a silicon strip detector.  Better particle identification device  Replace endcap calorimeter by pure CsI.  Faster readout electronics and computing system.

MCP-PMT (TOP)

New experimental group It will be practical to build a new detector by upgrading the existing Belle. However, the experimental group will be a new group, not an extension of the present Belle collaboration. Name of the new group will not be Belle or SuperBelle. 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.

Experiment at KEKB KEKB/Belle upgrade Detector Study Report (March 08) Final detector design (April 09) Pre kick-off meeting (March 08) Detector proposalsInternal review TDR BNM (January 08) One-day general meeting and an IB meeting at every BGM Meeting plan Actions to invite new collaborators Kick-off meeting (July 08)

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~ will be very useful to study the new sources of flavor mixing and CP violation. –Search for new CPV in b  s transition –Very precise test of CKM scheme –Search for lepton flavor violating  decays –Studies of H ± interactions with fermions –Very precise measurements of  S sin 2  W KEK Roadmap includes KEKB upgrade. KEKB machine upgrade plan  Oide’s talk Detector upgrade necessary to improve BKG/rate immunity. New collaboration to be formed soon.

Barrel PID (TOP) Quartz: 255cm L x 40cm W x 2cm T –Focus mirror at 47.8deg. angle( )  y( ); correct chromatic dispersion t( ) Multi-anode (GaAsP) MCP-PMT –Linear array (5mm pitch), Good time resolution (<~40ps) MCP-PMT lifetime to be checked re-polishing going on

New resonances  c ’ & e + e -  cccc D 0 * 0 & D 1 * 0 X(3872)  c * baryon triplet X(3940), Y(3940)  c2 ’ Y(4660) Y(4008) D sJ (2700)  cx (3090) Z(4430) D sJ (2317/2460) D sJ (2860) Y(4260) Y(4320) New resonances found at Belle Among them X （ 3872 ） and Z （ 4430 ） are considered to be “exotic” states. Among them X （ 3872 ） and Z （ 4430 ） are considered to be “exotic” states. More and more exotic states will be Observed by the upgraded KEKB. More and more exotic states will be Observed by the upgraded KEKB. More than 10 new resonances have been found at Belle More than 10 new resonances have been found at Belle

Bkg & TRG rate in future KEKBSuperB Luminosity (10 34 cm -2 sec -1 ) ~1.7~50 HER curr. (A) LER curr. (A) vacuum (10 -7 Pa) ~ Bkg increase-x 20 TRG rate (kHz) phys. origin Bkg origin Shynchrotoron radiation Beam-gas scattering (inc. intra-beam scattering) Radiative Bhabha SVDCDCPID / ECLKLM KEKB Bkg x10 Bkg x20 Bkg

Endcap PID (A-RICH) N pe = 9.1,  (track) = 4.2 mrad achieved ~5.5  separation for 4 GeV/c K/  “ Focusing ” Aerogel radiator Photon Sensors –Sensitive to single photon High QE >~ 20 % High gain –Position detection accuracy: ~5x5 mm 2 –Large effective area: >~ 70 % –Operational with 1.5 Tesla magnetic field Hybrid (Avalanche) Photon Detector MCP (Micro Channel Plate) PMT Si-PM/MPPC