1 Superb prospects: Belle & KEKB upgrades Kay Kinoshita University of Cincinnati Belle Collaboration July 26-31, 2009 motivationplanstatus (CP Violation III)

2 Superb prospects: Belle & KEKB upgrades Kay Kinoshita University of Cincinnati Belle Collaboration July 26-31, 2009 motivationplanstatus (Detectors II)

3 Experiments (-2009) CP asymmetry manifested in diverse processes in B decay -> many measurements, (over)constrain CKM B-factories ( ) Primary goal: establish unitarity & complex phase of CKM matrix Kobayashi & Maskawa (1973) proposed 3 rd generation of particles Explain CP violation in K, predict for B found consistent with unitarity 2008 Nobel

4 B-factories ( ) … + many other successes + more measurements, on B, charm, tau, 2-photon, ϒ (4S), ϒ (10860), B s, ϒ (3S), ϒ (1S),... Addressing CP, CKM, QCD, HQ spectroscopy, LFV, NP, Dark Matter,... Headliners new charmonia, charmonium-like states, ISR, D sJ, new charmonia, charmonium-like states, ISR, D sJ, many B decays many B decays D 0 mixing D 0 mixing limits on/hints of New Physics limits on/hints of New Physics

5 B pairs world sample KEKB/Belle KEKB + PEP-II ~946/fb (6/09) ~553/fb design luminosity of KEKB L max = 2.1 x /cm 2 /sec (design=1.0) PEP-II/BaBar ~ 1.5 billion BB pairs

6 Why collect more? With 1.5G Bpairs (+similar #’s of c, tau) at Belle+Babar many best measurements: testing CKM unitarity, exploring SM-suppressed/forbidden regions φ 1, φ 2, φ 3  β, α, γ ρ 0 ρ 0 ( φ 2 ), Dalitz ( φ 3 ), b->d γ SM- suppressed B & D processes Lepton universality B-> τν, B->D (*) τν LFV τ->µγ many of these measurements/limits are statistically limited

7 furthermore... to account for baryon asymmetry of universe... NEED other source(s) of CP violation Why collect more?

8 complementary to LHC: γ, K L detection; hermeticity -> neutrinos With x10 2 luminosity, in a facility designed for CP studies, a significant new window b->s penguin( φ 1 ) b->s γ, b->d γ, B-> sl + l - RH currents in B->{s} γ CP in D mixing Lepton universality SM-forbidden lepton processes ρ 0 ρ 0 ( φ 2 ), Dalitz ( φ 3 ), b->d γ Higgs in B-> τν, B->D (*) τν LFV τ->µγ

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10 V tb *2 V td 2 V cb V cs *  V tb *2 V td 2 V cb V cs * mixing+tree SM: “golden” vs “other” sin2 φ 1 (sin2 β) V cb * V cs  V cb * V cs tree (real V ij ) “golden” B -> J/ ψ K s => relative phase = 2 φ 1, CP asymmetry ~ sin 2 φ 1 identical hadronic processes -> same |Amplitude| V cb * V cs V cb * V cs real => zero phase difference well-measured rate mixing V tb *2 V td 2 phase = arg(V tb *2 V td 2 )=2 φ 1

11 “other” sin2 φ 1 b -> ss ̅ s: identical reasoning “New Physics” w complex phase φ new ---> CP asymmetry ≠ sin (2 φ 1 ) V tb *2 V td 2 V tb V ts *  V tb *2 V td 2 V tb V ts * mixing+penguin V tb * V ts  V tb * V ts penguin (real V ij ) V tb * V ts V tb * V ts real => zero phase difference => relative phase = 2 φ 1, CP asymmetry ~ sin 2 φ 1

12 Standard Model: “other” sin2 φ 1 caveat: (small) theory correction -> mostly >0 V tb * V ts  V tb * V ts penguin (real V ij ) b -> ss ̅ s: identical reasoning

13 Heavy Flavor Averaging Group Average “sin2 φ 1 ” from b->s penguins Naïve World Average sin2 φ 1 (b->sqq ̅ )= 0.62  0.04 Compare to cc ̅ s: sin2 φ 1 (b->cc ̅ s) =  CL = 0.19 (1.3 σ ) difference is < 0

14 “sin2 φ 1 ” sensitivity to New Physics Already exploring “New” region: to improve sensitivity, need better statistics systematics theory corrections (Luminosity Projections) ✪ Babar: PRD79, (2009)

15 Right-handed currents Atwood, Gronau, Soni (PRL 79, 185 (1997)) Atwood, Gershon, Hazumi, Soni (PRD 71, (2005)) large asymmetry right-handed current Currently: consistent with no RH currents (but need more data for good sensitivity...) in SM B 0 → X s CP γ is ~flavor-specific ( γ polarization) -> low CP-asymmetry, O(3%)

16 Right-handed currents CP asymmetry in B → K S π 0 γ precision integrated luminosity

17 B + -> τ + ν τ : constraints on charged Higgs {WS Hou, PRD 48, 2342 (1993)} (extrapolation) 50 ab -1 allowed (Belle) 0.65 ab –1

18 Lepton universality: B   SM: B(B->  ) = 1.6x10 -4 B(B->  ) = 7.1x10 -7 B(B-> e ) = 1.7x B->  B->  deviations from SM sensitive to NP Luminosity (ab -1 ) Significance expect observation with ~4 ab -1 10

19 Lepton universality: B  D (*)  c b  H/WH/W  B(B 0 ->D *-  ) = (2.0±0.4±0.4)% [PRL 99, (2007)] –Ratio (  /  ) is sensitive to charged Higgs (similar to B   ) M.Tanaka universality via semileptonic decays B   X decays probe NP in different ways: B   : H-b-u vertex B  D  : H-b-c vertex

20 D mixing/CP violation For 75 ab –1 x=0.8 y=0.8 ~4 σ significance on 1-|q/p| |q/p|=0.9 >4 σ significance on x >5 σ significance on y

21 of B’s => what we need is

22 Super KEKB Luminosity projection 3 year shutdown for upgrade ~ ab -1 L~8x10 35 cm -2 s -1 50ab -1 by ~2020 x50 present

23 KEKB luminosity upgrade strategy “nano-beam” scheme (proposed by P. Raimondi for Italian Super B factory) 1.8A(LER)/1.45(HER)  3.8A/2.2A 6.5(LER)/5.9(HER)  0.26/0.26

24 KEKB luminosity upgrade strategy LERHER Emittance xx nm Coupling y/xy/x % Horizontal beta at IP x*x* mm Vertical beta at IP y*y* 0.26 mm Horizontal beam size x*x* mm Vertical beam size y*y* mm Bunch length zz 5mm Half crossing angle  30mrad Beam EnergyE Beam CurrentI A Number of bunchesnbnb 2252 Beam-beam parameter yy LuminosityL8x10 35 (8.5x10 35 with CW)cm -2 s -1 New lattice: still under study Tentative machine parameters

25 <100 nanometers Note that KEK Accelerator Test Facility (linear collider damping ring) has achieved 35 nm

26 Detector: Background projections Issues Radiation damage Occupancy Fake hits, pile-up Event rate Belle detector SuperKEKB (hi-current design) normalized to current rates Design upgrade to tolerate ~20X at full luminosity Year

27 Detector: Belle II Upgrade of Belle to operate w 20X background, 50X event rate baseline: current performance + improved PID Design Study Report arXiv: Design Study Report arXiv: Baseline design – not final Satisfies minimum requirements Many alternatives under study: Design to be finalized in 2009 Physics studies Detector simulations based on Geant 3, fast simulator, Geant 4

28 Belle II baseline New dead-time-free pipelined readout and high speed computing systems Faster calorimeter with waveform sampling and pure CsI (endcap) New particle identifier with precise Cherenkov device: (i)TOP or fDIRC. Endcap: Aerogel RICH Si vertex detector with high background tolerance (+2 layers, pixels) Background tolerant super small cell tracking detector KL/  detection with scintillator and next generation photon sensors

29 Baseline design BellesBelle Detector type4-DSSD2-DEPFET pixel + 2- DSSD + 2-DSSD (short strips/angled) chip-on-sensor lyr 5&6 Inner radius15 mm10 mm Outer radius70 mm120 mm DSSD readoutHold 3µs/readout 27µs pipelined Readout time800 ns50 ns Silicon inner tracker improve vertexing -> thin innermost 2 layers, reduce inner radius improve K S acceptance -> increase outer radius background/occupancy -> striplets, pixels, pipelined readout + standalone tracking, dE/dx

30 Baseline design Silicon inner tracker Layers 5 and 6 shorten strips angle to reduce total area

31 Baseline design BelleBelle II (t>0) Inner radius77 mm160 mm Outer radius880 mm1140 mm Inner layer cell size 12 mm8 mm # sense wires Drift chamber improve momentum resolution -> increase outer radius improve dE/dx -> longer radial path background/occupancy -> smaller cells

32 Baseline design BelleBelle II (t>0) BarrelAerogel TOF dE/dx in CDC Cerenkov time-of- propagation (TOP) Endcap(dE/dx)Aerogel RICH Particle ID improve K/ π for b->s vs b->d, etc. add endcap PID reduce material in front of calorimeter

33 Baseline design Particle ID Barrel TOP counter with imaging charged particle quartz radiator Cherenkov photon focusing mirror image expansion region Options 2-pc (double readout) 1-pc, time only 1-pc, with standoff, imaging Photon time-of-propagation due to θ c difference; at 3 GeV, 1m path, Δ t ~ 75 ps π /K time-of-flight; at 3 GeV, 1m path, Δ t ~ 50 ps Photon detection Multi-anode Microchannel plate PMT (MCP-PMT) Δ t<40 ps Readout BLAB3 ASIC “oscillioscope on a chip”

34 Baseline design Particle ID Endcap Proximity focusing Aerogel RICH Multi-index to minimize ring width n = indices TBD Photon detector requirements high QE, >20% high gain 5mm x 5 mm segmentation >70% coverage operate in B=1.5 T Candidates Hybrid APD MCP-PMT (includes TOF)

35 Baseline design BelleBelle II (t>0) BarrelCsI (Tl) +waveform sampling/fitting Endcap Rise time Photodetector CsI(Tl) 1000 ns Si photodiode Pure CsI 30 ns PMT +waveform sampling/fitting Electromagnetic calorimeter reduce background without loss of resolution Alternatives under study Bismuth silicate (BSO) Lead Tungstate (PbWO 4 )

36 Baseline design BelleBelle II (t>0) BarrelGlass RPC, streamer mode Same RPC (avalanche mode?) EndcapGlass RPC, streamer mode Plastic scintillator x-y strips K L /muon detector reduce background in endcap

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38 Placement of KEKB upgrade on Roadmap (Jan. 2008) -> official priority of KEK 3-year upgrade: 2010–2 L ∼ 8 × cm −2 s −1 Funding: 3.2 x 10 9 ¥ (~$32M) for FY 2009 request for construction (2010-): $350M

39 Belle II Collaboration New international collaboration (not extension of present Belle) Belle First meeting December 2008 next meeting Nov. 18-9, 2009 Spokesperson: P. Krizan (Ljubljana) US institutions University of Cincinnati University of Hawaii Virginia Tech Wayne State

40Summary B-factories , >1.4x10 9 B pairs: firmly established CKM as main source of CP asymmetry at low energy placed multiple constraints on CKM unitarity high precision -> probe for New Physics rare processes as windows to New Physics incl. D mixing, tau decays ~10 2 X luminosity will probe >1 TeV mass scale precision CKM, CP, lepton universality, LFV (complementary to LHC) KEKB upgrade for L=8 x included in KEKB Roadmap SuperKEKB/Belle II plans well underway new international collaboration forming