Belle II at SuperKEKB Kurtis Nishimura University of Hawaii (on behalf of the Belle II Collaboration) 11th Conference on the Intersections of Nuclear and Particle Physics June 3, 2012 TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AAAAAAA

B Factory Physics Proposals (1994) Primary physics goal of the B factories: Measure CP violation in B mesons, confirm the Kobayashi-Maskawa mechanism of CP violation... CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB

Measuring CPV at Asymmetric B Factories Search for time dependent decay asymmetries: Belle 8.0 GeV e- , 3.5 GeV e+ ¯° = 0.42 BaBar 9.0 GeV e- , 3.1 GeV e+ ¯° = 0.56 e- e+ CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB

Time Dependent CPV – Success! (2001) CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB

Luminosity at B Factories (1999-2010) Performance far exceeding design values! World record peak luminosity (Belle): 2.1 x 1034 cm-2 s-1 CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB

Variety of Successes from B Factories Belle and BaBar have made a wide range of achievements over ~10 year running period: Observation of CP violation in B decays. CKM measurements of: Matrix elements. Unitary triangle angles. CKM verified to ~O(10%) Direct CP violation: B  K ¼ New hadronic states: X,Y,Z mesons Rare probes of new physics: b  s ° b  s B0 tag _ BaBar LOI (1994) CKM Fitter (2012) CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB

Variety of Successes from B Factories Belle and BaBar have made a wide range of achievements over ~10 year running period: Observation of CPV in B decays. CKM measurements of: Matrix elements Unitary triangle angles CKM verified to ~O(10%) Direct CP violation (e.g., B  K ¼). New hadronic states: X(3872),Y,Z,… Rare probes of new physics, e.g., B  ¿ º b  s ° , b  s Rare ¿ decays Observation of D mixing. X(3872) CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB

Nishimura - Belle II @ SuperKEKB What next…? Continue to improve precision on CKM picture, search for deviations: 50ab-1 today Explore current hints of possible new physics that already exist, e.g.,: ~few ¾ tension in current CKM fit between measured/predicted B  ¿ º and sin 2¯ “B  K ¼ puzzle” – difference in K+¼-/K+¼0 direct CP asymmetries. Direct CP violation in D decays. CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB

Nishimura - Belle II @ SuperKEKB CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB

Nishimura - Belle II @ SuperKEKB Upgrade! KEKB  Super KEKB Belle  Belle II KEKB SuperKEKB+ SuperB PEP-II CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB

SuperKEKB x 40 Gain in Luminosity L=8·1035 s-1cm-2 e- 2.3 A Colliding bunches Belle II New IR e- 2.3 A New superconducting /permanent final focusing quads near the IP New beam pipe & bellows e+ 4.0 A Replace short dipoles with longer ones (LER) Add / modify RF systems for higher beam current Low emittance positrons to inject Positron source Damping ring Redesign the lattices of HER & LER to squeeze the emittance New positron target / capture section Low emittance gun TiN-coated beam pipe with antechambers Low emittance electrons to inject L=8·1035 s-1cm-2 x 40 Gain in Luminosity

Luminosity Prospects,Detector Requirements ~50 ab-1 (2022) ~10 ab-1 (2018) Current B factories Design L: 8 x 1035 cm-2 s-1 Increased luminosity: ~10-20x higher backgrounds, rad. damage Increased trigger rates (0.5  200 kHz). Need to maintain excellent performance, hermeticity. Significant detector upgrades! Belle event with increased background overlaid. CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB

Nishimura - Belle II @ SuperKEKB The Belle II Detector RPC m & KL counter: scintillator + Si-PM for end-caps CsI(Tl) EM calorimeter: waveform sampling electronics, pure CsI for end-caps 7.4 m 3.3 m 1.5 m 4 layers DSSD → 2 layers PXD (DEPFET) + 4 layers DSSD 7.1 m Time-of-Flight, Aerogel Cherenkov Counter → Time-of-Propagation counter (barrel), proximity focusing Aerogel RICH (forward) Central Drift Chamber: smaller cell size, long lever arm Belle II Technical Design Report: arXiv:1011.0352 CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB

Nishimura - Belle II @ SuperKEKB Vertex Detector Belle II: Pixels (2 layers) + SVD (4 layers) Belle: SVD (4 layers) DSSD strip layers pixel layers Vertexing improvements: ~25% Improvement in vertex resolution. ~30% higher KS  ¼+¼- efficiency. DEPFET Pixel Mockup Increased sensitivity to b  s ° TCPV: SCP suppressed by ms / mb in SM. Enhanced in LR symmetric models. Currently statistics limited. Silicon Vertex Detector Nonresonant KS ¼0 ° Resonant K*0 ° All KS ¼0 ° CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB

Nishimura - Belle II @ SuperKEKB Central Drift Chamber longer lever arm improve resolution of momentum and dE/dx Vital for “full reconstruction”: Fully reconstruct “tag” B to determine “signal” B flavor, charge, momentum. (7.0 GeV) (4.0 GeV) Allows measurement of modes with missing energy, neutrinos: B  K(*) º º B  ¿ º CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB

Time-of-Propagation (Barrel PID) TOP Concept Example x,t Hit Pattern Compact version of detection of internally reflected Cherenkov (DIRC) technique: Measure internally reflected Cherenkov pattern in x,y,t. Relies strongly on timing of detected photons. Typically separation between K,¼ is of order ~100 ps. 90±, 2 GeV Red - Pion Blue - Kaon t° (ns) CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB

Time-of-Propagation (Barrel PID) K§, ¼§ Focusing Mirror MCP-PMTs Quartz radiator Compact version of detection of internally reflected Cherenkov (DIRC) technique: Measure internally reflected Cherenkov pattern in x,y,t. Significant improvement over Belle threshold aerogel + time-of-flight. Hamamatsu SL-10 16-channel Micro-channel plate PMTs Excellent timing (¾t ~ 40 ps) Compact, integrated GSa/s waveform digitizing readout: TOP performance at 3 GeV/c 90% 128-channel integrated module CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB

Aerogel RICH (Endcap PID) Proximity focusing scheme: Aerogel Hamamatsu HAPD Slightly different indices of aerogel stacked  improve Cherenkov angle resolution. 90%  Excellent PID efficiency over wide momentum range. CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB

Improved PID Performance Significant improvement in K/¼ discrimination: Rare radiative processes: B  ½0 ( ¼+¼-) ° B  K* ( K+¼-) ° Other physics impact: K¼ CPV puzzle. Naively, for K+¼0, K +¼- we expect: ¢A = 0. Current Belle value (EPS 2011): ¢A = +0.112 § 0.028 @ 4¾ …but theoretical uncertainty can be large. Model independent sum rule: Gronau, PLB627, 82 (2005) current CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB

Improved PID Performance Significant improvement in K/¼ discrimination: Rare radiative processes: B  ½0 ( ¼+¼-) ° B  K* ( K+¼-) ° Other physics impact: K¼ CPV puzzle. Naively, for K+¼0, K +¼- we expect: ¢A = 0. Current Belle value (EPS 2011): ¢A = +0.112 § 0.028 @ 4¾ …but theoretical uncertainty can be large. Model independent sum rule: Gronau, PLB627, 82 (2005) current Projected w/ 50 ab-1 CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB

Electromagnetic Calorimeter Crystals: Barrel: reuse existing CsI(Tl). Endcaps: (possibly staged) upgrade to pure CsI.  Better performance & radiation hardness. Readout electronics: Upgrade to 2 MHz waveform sampling. Online signal processing.  Improved energy resolution. CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB

Nishimura - Belle II @ SuperKEKB Missing Energy Modes Belle B  ¿ º [PRD82:071101] Fully reconstruct one B, measure Emiss for signal B. Examples: B  ¿ º Current ~2.8 ¾ CKM fit tension. B  h º º Sets limits on right-handed currents. Bkg only. Sig + bkg Belle B  K*ºº [PRL99:221802] -- exp. signal (20xBr) exp. bkg 50 ab-1 W. Altmannshofer et al., JHEP 0904, 022 (2009). CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB

Nishimura - Belle II @ SuperKEKB KL and ¹ Detector Endcap: RPCs  scintillator to tolerate high BG. 14x(75 x-strips, 75 y-strips) per 90± sector. 16,800 total channels w/ waveform sampling readout. Barrel: Belle RPCs mostly to be reused. Inner two layers  scintillator. Iron plate Aluminium frame x-strip plane y-strip plane Y strip X strip Photon-counting with Hamamatsu MPPCs and waveform sampling readout CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB

Belle II Physics Program Belle II provides many opportunities to search for new physics at intensity frontier: *From Enrico Lunghi’s slides on Wednesday CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB

Belle II Physics Program Very broad physics program within Belle II! “Physics at Super B Factory”, arXiv:1002.5012 CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB

Nishimura - Belle II @ SuperKEKB Summary Super KEKB & Belle II are approved by Japanese government. Accelerator and detector upgrades are underway. Belle II Technical Design Report: arXiv:1011.0352 Planning to collect 50 ab-1 by 2022. Broad physics program. More details: arXiv:1002.5012 ~400 members from over 60 institutes in 19 countries: New members welcome! Visit: http://belle2.kek.jp CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB

Nishimura - Belle II @ SuperKEKB Backup CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB

Increasing Luminosity for SuperKEKB Target luminosity (8 x 1035 cm-2 s-2): ~40x KEKB Beam current I: beam current b*: trajectories envelope at IP xy  (by */ey ) beam-beam parameter e: beam emittance σ*: beam size RL,Rξy: geometrical reduction factors (crossing angle, hourglass effect) Beam-beam parameter Vertical beta function @ IP E (GeV) LER/HER β*y (mm) β*x (cm) εx (nm) φ (mrad) I (A) L (cm-2s-1) KEKB 3.5/8.0 5.9/5.9 120/120 18/24 11 1.6/1.2 2.1 x 1034 SuperKEKB 4.0/7.0 0.27/0.41 3.2/2.5 3.2/1.7 41.5 3.6/2.6 80x1034 Strategies: Reduce vertical beta function at IP: collide very small, focused beams. Nano-beam scheme invented by P. Raimondi. 2. Increase beam currents. sx~100mm, sy~2mm sx~10mm, sy~60nm CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB

Nishimura - Belle II @ SuperKEKB SuperKEKB Parameters CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB

Nishimura - Belle II @ SuperKEKB CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB

Nishimura - Belle II @ SuperKEKB Central Drift Chamber longer lever arm improve resolution of momentum and dE/dx CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB

Missing Energy Modes: B-  ¿ - º Tension between the global CKM fit and : Current world ave. ~2.8 ¾ discrepancy Expectation from CKM fit Better measurement of B(B  ¿ º) may reveal source of the tension. Tag-side information vital when ¸2 º’s in final state! Signal is seen as zero excess EECL. Bkg only. Sig + bkg Example w/ semileptonic tag, 657M BB PRD82:071101 (2010) CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB

Nishimura - Belle II @ SuperKEKB B  ¿ º at Belle II Also sensitive to new physics: In type-II Two-Higgs Doublet Model (THDM), the SM branching fraction of B-  ¿ - º is modified: Belle II discovery region with 5 ab-1 Assumes improvements in theory values: 5% |Vub| error 5% fB error 5 ¾ discovery region current 95% exclusion CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB

Nishimura - Belle II @ SuperKEKB B  ¿ º at Belle II Also sensitive to new physics: In type-II Two-Higgs Doublet Model (THDM), the SM branching fraction of B-  ¿ - º is modified: Belle II discovery region with 50 ab-1 Assumes improvements in theory values: 2.5% |Vub| error 2.5% fB error 5 ¾ discovery region current 95% exclusion *Does not yet account for improvements in full-recon efficiency. Recently work suggests O(2x) improvements. CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB

Nishimura - Belle II @ SuperKEKB B  D* ¿ º CIPANP - June 3, 2012 Nishimura - Belle II @ SuperKEKB