SuperKEKB B factory April 12, 2006 Nobu Katayama (KEK)

12/04/2006 N. Katayama2 Outline  Physics cases at Super KEKB  Accelerator parameters and R&D status  Detector R&D status

12/04/2006 N. Katayama3 Super KEKB  Asymmetric energy e  e  collider at E CM =m(  (4S)) to be realized by upgrading the existing KEKB collider.  Super-high luminosity  4  /cm 2 /sec  5  10 9 BB per yr.  4  10 9     per yr.  4  10 9     per yr. Belle with improved rate immunity Higher beam current, more RF, smaller  y * and crab crossing  L = 4  /cm 2 /sec

12/04/2006 N. Katayama4  Are there New Physics phases and new sources of CP violation beyond the SM ?  Compare CPV angles from tree and loops.  Are there new flavor-changing interactions with b, c or  ?  b  s bar, D-Dbar mixing+CPV+rare,   Are there right-handed currents ?  b  s  CPV, B  V V triple-product asymmetries More questions in flavor physics Can we answer such questions at a Super B Factory? _d_d b s _s_s B  _d_d s KsKs

12/04/2006 N. Katayama5 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 SM only A SUSY A SM | Effect of SUSY phase  SUSY on CPV in B  K decay In general, if SUSY is present, the s-quark mixing matrix contains complex phases just as in the Kobayashi-Maskawa matrix.

12/04/2006 N. Katayama6 Sensitivity to new CP phases |A SUSY /A SM | 2  new physics Discovery region with 50 ab -1 Estimated error in the measurement of time dependent CP violation (For a particular set of SUSY model/parameters) We are here

12/04/2006 N. Katayama7 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:

12/04/2006 N. Katayama8 Sensitivity to new flavor mixing MC, 50 ab -1 Experimental result with 0.35 ab -1 Belle, 2005 These patterns were excluded by recent data from Belle. Standard model Sensitivity at Super KEKB  Zero-crossing q 2 for A FB will be determined with 5% error with 50ab -1.

12/04/2006 N. Katayama9 Poor tagsGood tags Belle Update 2005 (386 x 10 6 B pairs): Search for Right-Handed Currents in B  K S  0  In the SM, S should be close to zero (<0.10). Use the K S to determine the vertex. mbmb mbmb msms msms SM: γ is polarized, the final state almost flavor- specific. hep-ex/ (M X <1.8 GeV)

12/04/2006 N. Katayama10 NP and Right-handed currents in b  s   tCPV in B 0  K S  0   m heavy /m b enhancement for right-handed currents in many NP models  LRSM, SUSY, Randall-Sundrum (warped extra dimension) model  LRSM: SU(2) L  SU(2) R  U(1)  Right-handed amplitude   m t /m b :  is W L -W R mixing parameter  for present exp. bounds (  W R mass > 1.4TeV) | S( Ks  0  ~  is allowed.  Here an asymmetry does not require a new CPV phase D.Atwood, M.Gronau, A.Soni (1997) D.Atwood, T.Gershon, M.Hazumi A.Soni (2004) S(B  K*  K*  Ks  0 ) 50ab -1 5ab -1 Present Belle (stat.)

12/04/2006 N. Katayama11 “ B meson beam ” technique Υ ee ee B B  full reconstruction 0.2~0.3% for B + D H ± search in B  D (*)   (Br)/Br = 2.5% at 50 ab -1 Sensitivity of H ± search Application Constraint from B  Xs  BDBD B   (present) LHC 100fb -1

12/04/2006 N. Katayama12 B tagging provides a “ B-meson beam ” MC extrapolation to 50 ab  1 Observation of B ±  K ±  55 (compare to K +   + νν and K L   0 Extra EM calorimeter energy

12/04/2006 N. Katayama13 A Super B Factory is also a powerful  -charm Factory   Rich, broad physics program that covers B,  and charm physics..   Examples:   examination of rare charm modes   D 0 -D 0 bar mixing   searches for  with unprecedented sensitivity.

12/04/2006 N. Katayama14 Search for flavor-violating  decay  SUSY + Seesaw  Flavor violation by -Yukawa coupling.  Large LFV Br(    )=O(10 -7~9 ) Gaugino mass = 200GeV Present Belle Super-KEKB ll   l  ’ 3l3l   l Ks   B  Expected sensitivity at Super KEKB BR(    ) ~  tan 2  (m L 2 ) 32 m L 2 ~ ~ ( ) 4 1 TeV m SUSY  0  ~   (e)(e) (e)(e) ~~ 

12/04/2006 N. Katayama15 Search for New Physics in the Charm Sector c – the only heavy up-like quark experimentally accessible; New Physics Mechanisms may be different for u- and d-like quarks;  Rare Charm Decays, D-Dbar Mixing and CP Violation Exp.Int.lum. # recon. D 0 →K -  + Comments Belle 500 fb x x 10 6 in D* + →D 0  + p*(D*)>2.5 GeV Cleo-c 3 fb ψ(3770) 5.5 x x 10 4 CP-tagged CDF Run II 4.4 fb -1 3 x x 10 6 in D* + →D 0  +, p t >2 GeV BESIII 30 fb x 10 6 Super B Factory 5 ab -1 ~ 50 ab x 10 8 ~ 1.4 x x 10 7 (10 8 ) D* + →D 0  + with p*(D*)>2.5 GeV e.g. D 0 →  ; D 0(±) → H 0(±) l + l - ; D 0 → l + l - ; D 0(±) → V 0(±) 

12/04/2006 N. Katayama16 Clean environment  measurements that no other experiment can perform. Examples: CPV in B   K 0, B   ’K 0 for new phases, B  K S  0  for right- handed currents. “B-meson beam” technique  access to new decay modes. Example: discover B  K Measure new types of asymmetries Example: forward-backward asymmetry in b  s , s ee Rich, broad physics program including B,  and charm physics Examples: searches for    and D-D mixing with unprecedented sensitivity. Comparisons with LHCb

Super KEKB accelerator

12/04/2006 N. Katayama18 Bunch length (  s ) 7 ~ 9 mm -> 3 mm How to achieve the super-high luminosity Crab cavity

12/04/2006 N. Katayama19 Accelerator R&D  Vacuum components for higher current  Antechambers, coating, bellows, collimetors,,  Superconducting quadrupoles  High power RF components  Bunch-by-bunch feedback system  C-band linac  Beam diagnostics  Crab cavities

12/04/2006 N. Katayama20 Interaction Region Crab crossing  =30mrad.  y *=3mm New QCS Components to be upgraded Linac upgrade More RF power Damping ring New Beam pipe

12/04/2006 N. Katayama21 Crab cavity: a new idea for higher luminosity  Head-on collisions with finite crossing angle !  avoid parasitic collisions  collisions with highest symmetry  large beam- beam parameter

12/04/2006 N. Katayama22  First performance report expected in fall 2006  Factor ~2 gain in L peak may be expected within ~2 yrs  ~3  cm  2 s  1 within our reach  First performance report expected in fall 2006  Factor ~2 gain in L peak may be expected within ~2 yrs  ~3  cm  2 s  1 within our reach fall We are here

12/04/2006 N. Katayama23 Super KEKB components Antechamber Bellows MO-flange C-band RF cavity

12/04/2006 N. Katayama24

12/04/2006 N. Katayama25 Super KEKB: Proposed schedule Crab cavity 1.5x fb -1 5x ab -1 4x ab -1 L peak ( cm -2 s -1 ) L int 5x10 9 BB/yr. & also  +  -

Detector requirements and R&D status

12/04/2006 N. Katayama27 Requirements for 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.

12/04/2006 N. Katayama28 Super Belle 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

12/04/2006 N. Katayama29 Si vertex det. & Tracker 2-layer sensors at inner layer for robust vertexing R = 1 cm Self tracking of low momentum tracks. Dead time less readout at the luminosity of 5x10 35 / cm 2 /sec. Rejection of beam background that is 30 times severer than that in KEKB. Smaller cell size Lower hit rate for each wire. Shorter maximum drift time. Faster drift velocity Shorter maximum drift time SVD CDC 6 or more Layers Large area Si tracker

12/04/2006 N. Katayama30 Monolithic Active Pixel Sensor (MAPS) and Silicon striplet MAPS 10  m Key Features Thermal charge collection (no HV) Thin - reduced multiple-scattering,  conversion, background  target NO bump bonding – fine pitch possible (8000x geometrical reduction) Standard CMOS process - “System on Chip” possible X and Y (long) strip configuration U and V short strip configuration

12/04/2006 N. Katayama31 CAP3 – full-sized! 928 x 128 pixels = 118,784 ~4.5M transistors ! 21 mm Active area mm >93% active without active edge processing

12/04/2006 N. Katayama32 CAP3: Full-size Detector e-e+ # of Detector / layer ~ 32 End view 128 x 928 pixels, 22.5  m 2 ~120 Kpixels / CAP  m process CAP3 5-layer flex PIXRO1 chip Pixel Readout Board (PROBE) Side view Half ladder scheme Double layer, offset structure r~8mm Length: 2x21mm ~ 4cm 17 o 30 o r~8mm

12/04/2006 N. Katayama33 TOP counter  Cherenkov ring imaging using timing information Difference of path length  Difference of time of propagation (TOP) (+ TOF from IP) With precise time resolution (  ~40ps)

12/04/2006 N. Katayama34 MCP-PMT with GaAsP  GaAsP photo-cathode  Higher Q.E.  at longer wavelength → less chromatic error   3.5s K/p at 4GeV/c, q=70 ﾟ (1s improvement)  Square-shape MCP-PMT with GaAsP photo-cathode is developing with Hamamatsu Photonics Light propagation velocity inside quartz Photon sensitivity at longer wave length shows the smaller velocity fluctuation.

12/04/2006 N. Katayama35 GaAsP MCP-PMT performance  Wave form, ADC and TDC distributions  Enough gain to detect single photo-electron  Good time resolution (TTS=42ps) for single p.e.  Slightly worse than single anode MCP-PMT (TTS=32ps)  Next  Check the performance in detail  Develop with the target structure Single p.e. 0.5ns/div 20mV/div adc 1bin/0.25pc count pedestal single photon peak Gain ～ 0.96×10 6 1bin/25ps -10 tdc count TTS ～ 42ps

12/04/2006 N. Katayama36 Summary of Super KEKB upgrade  Why? – Search for new sources of flavor mixing and CP violation  How? – Increase N B, decrease  y *, and crab crossing: L =4  /cm 2 /s  New beam pipe, crab cavity, new injector with damping ring  Belle will also be upgraded  Ideas for even higher luminosity and better detector are desperately needed  Please join and help!