Peter Križan. University of Ljubljana and J. Stefan Institute. ECFA Plenary Meeting, CERN, Nov 25-26, University of Ljubljana

Transcription

1 Status t of SuperKEKB and Belle-II Peter Križan University of Ljubljana and J. Stefan Institute ECFA Plenary Meeting, CERN, Nov 25-26, 2010 University of Ljubljana Jožef Stefan Institute

2 Contents Physics case for a Super B factory SuperKEKB/Belle-II@KEK Accellerator Detector Status and prospects of the project

3 B factories: CP violation in the B system CP violation in B system: from the discovery (2001) to a precision measurement (2006) sin2φ 1 /sin2β from b ccs _B 0 tag B 0 tag World average 2008: sin2φ 1 = ±0.025 _ 535 M BB pairs _ Constraints from measurements of angles and sides of the unitarity triangle Remarkable agreement

4 B factories: a success story Measurements of CKM matrix elements and angles of the unitarity triangle Observation of direct CP violation in B decays Measurements of rare decay modes (e.g., B τν, Dτν) b s transitions: probe for new sources of CPV and constraints from the b sγ γ branching fraction Forward-backward asymmetry (A FB ) in b sl + l - has become a powerfull tool to search for physics beyond SM. Observation of D mixing Searches for rare τ decays Observation of new hadrons

5 Fantastic performance much beyond design values!

6 The KEKB Collider & Belle Detector SCC RF(HER) ARES(LER) Belle detector Ares RF cavity - e - (8 GeV) on e + (3.5 GeV) s m Υ(4S) Lorentz boost: βγ= mrad crossing angle - Operating since 1999 Peak luminosity (WR!) : 2. 1 x cm cm - 2 s -1 =2x design value e + source First physics run on June 2, 1999 Last physics run on June 30, 2010 L peak = 2.1x10 34 /cm 2 /s L > 1ab -1

7 D 0 D 0 oscillation (fb 1 ) Data size b dγ transition CP violation in B Kπ decay X(3872) Z(4430) + Anomalous CP violation in B Kπ decay CP violation in neutral B system B τν decay CP violation in penguin decays Last beam abort ceremony on June 30, 2010

8 What next? B factories is SM with CKM right? Next generation: Super B factories in which way is the SM wrong? Need much more data (two orders!) because the SM worked so well until now Super B factory However: it will be a different world in four years, there will be serious competition from LHCb and BESIII Still, e + e - machines running at (or near) Y(4s) will have considerable advantages in several classes of measurements, and will be complementary in many more

9 Power of e + e -, example: Full Reconstruction Method Fully reconstruct one of the B s to Tag B flavor/charge Determine B momentum Exclude decay products of one B from further analysis e (8GeV) Υ(4S) Decays of interest B B X u l ν, B K ν ν e+(3.5gev) B Dτν, τν π B full reconstruction B Dπ etc. (0.1~0.3%) Offline B meson beam! Powerful tool for B decays with neutrinos

10 Event candidate B - τ ν τ

11 Charged Higgs limits from B - τ ν τ b u W/H ± τ ν τ r H BF( B τν ) m tan 2 BF( B τν ) SM mh 2 2 B = = 1 tan β 2 limit on charged Higgs mass vs. tanβ ~0.5 05ab ab -1

12 b B D (*) τν Semileptonic decay sensitive to charged Higgs W/H ± c τ ντ Ratio of τ to μ,e could be reduced/enhanced significantly Compared to B τν 1.Smaller theoretical uncertainty of R(D) For B τν, There is O(10%) fb uncertainty from lattice QCD T.Miki, T.Mimuta and M.Tanaka:hep-ph Large expected Br (Ulrich Nierste arxiv: ) 3. Differential distributions can be used to discriminate W + and H + 4. Sensitive to different vertex B τν: H-b-u, B Dτν: H-b-c (LHC experiments sensitive to H-b-t)

13 B Dτν Exclusion plots for tanβ and H + mass for 5ab -1 and 50ab -1

14 B D * τν similar constraints on H + [PRL 99, (2007)] 535M BB Tag side B mass combinatorial background peaking background (D *- eν)

15 B Kνν, B ~ B K*νν, B ~ SM: penguin+box Look for departure from the expected value information on couplings C ν R and C ν L compared to (C ν L) SM B K (*) νν Theory arxiv: adopted from W. Altmannshofer et al., JHEP 0904, 022 (2009) present exclusion limits Again: fully reconstruct one of the B mesons, look for signal (+nothing else) in the rest of the event. 50 ab -1 arxiv: not LHCb

16 CP violation in B K S π 0 γ CP violation in B K S π 0 γ decays: Search for right-handed currents B K*γ, B ~ δs ~0.2 2(present) 5 ab -1 ~a few % at 50 ab ab -1 adopted from HFAG not LHCb

17 LFV and New Physics γ τ lγ χ% 0 τ 3l,lη τ μ h μ() s τ τ% μ% ( e % ) μ () e μ( s ) 2 (m l% ) 23(13) SUSY + Seasaw Neutral Higgs mediated decay. Large LFV Br(τ μγ)=o(10-7~9 ) Important when MSUSY >> EW scale. Br( τ 3 μ) = 2 4 ( m ) L% 32 1TeV 2 6 Br( τ μγ) 10 tn a β ( m ) 7 L% 2 32 tan β 100GeV = m m L% SUSY m 60 m L % A model Br(τ μγ) Br(τ lll ) msugra+seesaw SUSY+SO(10) SM+seesaw Non-Universal Z SUSY+Higgs

18 Rare τ decays LF violating τ decay? Upper limits Theoretical predictions compared to present experimental limits τ μγ μ eγ τ eγ Integ. Lum.( ab -1 ) Reach of B factories Super B factories T.Goto et al., 2007

19 B Y(4S) Charm mixing and CP Charm FCNC τ Physics B s Y(5S) ΛΠ 2009 M. Giorgi, ICHEP2010

20 Physics with 50ab -1 Recent update: Physics at Super B Factory (Belle II authors + guests) hep-ex > arxiv:

21 Accelerator

22 Need O(100x) more data Next generation B-factories SuperKEKB SuperB 40 times higher luminosity KEKB PEP-II

23 How to do it? upgrade KEKB and Belle OHO TSUKUBA Area (Belle) High Energy Ring (HER) for Electron HER LER Interaction Region Low Energy Ring (LER) for Positron NIKKO Area Area WIGGLER RF (TRISTAN Accumulation Ring) e + /e - WIGGLER RF RF RF LER R Electron Positron HER Linac RF RF FUJI Area

24 Strategies for increasing luminosity - - (1) Smaller β * y (2) Increase beam currents Nano-Beam scheme (3) Increase ξ y Collision with very small spot-size size beams Invented by Pantaleo Raimondi Peter Križan, for Ljubljana SuperB

25 Machine design parameters parameters KEKB SuperKEKB LER HER LER HER units Beam energy Eb GeV Half crossing angle φ mrad Horizontal emittance εx nm Emittance ratio κ % Beta functions at IP βx * /βy * 1200/5.9 32/ /0.31 mm Beam currents Ib A beam-beam parameter ξy Luminosity L 2.1 x x cm -2 s -1 Small beam size & high current to increase luminosity Large crossing angle Change beam energies to solve the problem of LER short lifetime

26 KEKB to SuperKEKB Belle II Colliding bunches e- 2.6 A New IR New beam pipe & bellows e+ 3.6 A New superconducting /permanent final focusing quads near the IP Replace short dipoles with longer ones (LER) Redesign the lattices of HER & LER to squeeze the emittance Low emittance positrons to inject Damping ring Add / modify RF systems for higher beam current Positron source New positron target / capture section TiN-coated beam pipe with antechambers Low emittance gun Low emittance electrons to inject To get x40 higher luminosity

27 Detector

28 10 cm Requirements for the Belle II detector Critical issues at L= 8 x /cm 2 /sec Higher background ( 10-20) ) - radiation damage and occupancy - fake hits and pile-up noise in the EM Higher event rate ( 10) - higher rate trigger, DAQ and computing Require special features - low p μ identification sμμ recon. eff. - hermeticity ν reconstruction Solutions: Replace R l inner layers of the vertex detector with a pixel detector. Replace inner part of the central tracker with a silicon strip detector. Better particle identification device Replace endcap calorimeter crystals Faster readout electronics and computing system. BELLE 10 cm BELLE TDR published arxiv: v1 [physics.ins-det] 10 cm

29 Belle II in comparison with Belle SVD: 4 DSSD lyrs 2 DEPFET lyrs + 4 DSSD lyrs CDC: small cell, long lever arm ACC+TOF TOP+A RICH ECL: waveform sampling, pure CsI for end caps KLM: RPC Scintillator +SiPM (end caps) Parameters are preliminary Y. Ushiroda, Peter Križan, ICHEP2010 Ljubljana

30 Vertex Detector DEPFET: Beam Pipe DEPFET DSSD Layer 1 Layer 2 Layer 3 Layer 4 Layer 5 Layer 6 r = 10mm r = 14mm r = 22mm r = 38mm r = 80mm r = 115mm r = 140mm Mechanical mockup of pixel detector Prototype DEPFET pixel sensor and readout A prototype ladder using the first 6 inch DSSD from Hamamatsu has been assembled and tested. 30

31 Expected performance: vertexing σ[μm] ] Less Coulomb scatterings Belle σ[μm m] Belle σ = a + b pββ sin ν θ Pixel detector close to the beam pipe Belle II Belle II pβsin(θ) 3/2 [GeV/c] pβsin(θ) 5/2 [GeV/c] B vertex γ γ Ks track π + π IP profile B decay point reconstruction with K S trajectory γ Larger radial coverage of SVD

32 Particle identification systems s Barrel PID: Time of Propagation Counter (TOP) Endcap PID: Aerogel RICH (ARICH) 200mm Quartz radiator Focusing mirror Small expansion block Hamamatsu MCP-PMT PMT (measure t, x and y) Aerogel radiator n~1.05 Hamamatsu HAPD + new ASIC Aerogel radiator Hamamatsu HAPD + readout 200

33 Barrel PID: Time-of-propagation (TOP) counter Cherenkov ring imaging with precise time measurement. Reconstruct angle from two coordinates and the time of propagation p of the photon Quartz radiator (2cm) Photon detector (MCP-PMT) Good time resolution ~ 40 ps Single photon sensitivity in 1.5 T Wave-form sampling read-out

34 TOP (Barrel PID) Beam spot quartz Quartz radiator 915mm 2.6m L x 45cm W x 2cm T Excellent surface accuracy MCP-PMT Hamamatsu 16ch MCP-PMTPMT Good TTS (<35ps) & enough lifetime Multialkali photo-cathode SBA Beam test in 2009 # of photons consistent Time resolution OK beam data 1 st 2 nd 3 rd Time of arrival Simulation 875mm 1 st 2 nd 3 rd 2 nd 1 st 3 rd # of photons [1count/25ps] [1count/25ps]

35 Aerogel RICH (endcap PID) Aerogel Test Beam setup Clear Cherenkov image observed Hamamatsu HAPD peak Q.E. ~33% ( Super Bialkali ) Cherenkov angle distribution RICH with a novel focusing radiator a two layer radiator Employ multiple layers with different refractive indices Cherenkov images from individual layers overlap on the photon detector. 6.6 σ π/k at 4GeV/c!

36 KLM upgrade in the endcaps Scintillator-based KLM (endcap) Two independent (x and y) layers in one superlayer made of orthogonal strips with WLS read out Photo-detector = avalanche photodiode in Geiger mode (SiPM) ~120 strips in one 90º sector (max L=280cm, w=25mm) y-strip ~30000 read out channels plane Geometrical acceptance > 99% Iron plate x-strip Mirror 3M (above plane groove & at fiber end) Optical glue increase the light yield ~ ) WLS: Kurarai Y mm Aluminium frame GAPD Diffusion reflector (TiO 2 ) Strips: polystyrene with 1.5% PTP & 0.01% POPOP ΝΙΚΗΕΦ 2008/2/28 Toru Iijima, BINP, Novosibirsk 36

37 Status of the project

38 Belle II Collaboration 13 countries/regions, 56 institutions ~350 collaborators, ~110 from Europe

39 European groups of Belle-II Austria: HEPHY (Vienna) Czech Republic: Charles University in Prague Germany: G U. Bonn, U. Giessen, U. Goettingen, U. Heidelberg, KIT Karlsruhe, LMU Munich, MPI Munich, TU Munich Poland: INP Krakow Russia: ITEP (Moscow), BINP (Novosibirsk), IHEP (Protvino) Slovenia: J. Stefan Institute, U. Ljubljana, U. Maribor, U. Nova Gorica Sizeable fraction of the collaboration: in total ~110 collaborators out of ~350!

40 European groups of Belle-II The European groups have major responsibilities s in some essential detector ec systems: Pixel vertex detector (DEPFET) Silicon strip vertex detector Particle identification systems (endcap Aerogel RICH, barrel Time-of- Propagation counter) Electromagnetic calorimeter Muon detector based on scintilator strips They are also contributing substantially to the computing and software, as well as to the set-up of the physics program.

41 Open Collaboration Meeting Series 6 th Open Meeting of the Belle II Collaboration (July 5-7, 2010, KEK, Japan) 5 th Open Meeting of the Belle II Collaboration (March 31 April 2, 2010, KEK, Japan) 4th Open Meeting of the Belle II Collaboration ation (November 18-20, 2009, KEK, Japan) 3rd Open Meeting of the Belle II Collaboration (July 7-9, 2009, KEK, Japan) 2nd Open Meeting of the Belle II Collaboration (March 17-19, 2009, KEK, Japan) 1st Open Meeting of the Belle II Collaboration (December 10-12, 2008, KEK, Japan) 2nd Open Meeting of the SuperKEKB proto-collaboration (July 3-4, 2008, KEK, Japan) 1st Open Meeting of the SuperKEKB proto-collaboration (March 19-20, 2008, KEK, Japan)

42 Big step forward

43 SuperKEKB/Belle II funding Status 5.8 oku yen (~7 MUSD) for Damping Ring (FY2010) 100 oku yen (~110 MUSD) for the machine Very Advanced Research Support Program (FY ) Continue efforts to obtain additional funds to complete construction as scheduled regular Japanese budget. Several non-japanese funding agencies have already allocated sizable funds for the upgrade. construction started!

44 SuperKEKB Main Ring schedule Oct. 20, 2010 FY2010 FY2011 FY2012 FY2013 FY2014 FY2015 KEKB operation Tunnel clear Remove magnets and beam pipes Beam pipes (LER) Design Beam pipes pp (HER) Design Magnets & Power supplies Beam monitors and Control RF system IR hardware QCS prototype Base plates Fabrication Design / Fabrication TiN coating Fabrication Design & Fabrication Field measurement Install Cabling / Check Layout change / Add stations / Cavity improvements Infrastructure QCS fabrication Building construction Install Install Alignment Test Conditioning Install & test Cooling system MR commissioning Physics Run

45 Linac upgrade and DR construction schedule Oct. 20, 2010 FY2010 FY2011 FY2012 FY2013 FY2014 FY2015 Linac upgrade Low emittance e gun Linac commissioning i i R&D Construction e+ new matching & L band acc. R&D Construction PF injection Buildings 3T 3 2T Study (A1 gun) DR jnct. Damping Ring Tunnel & building Base plan Design Tunnel construction Building construction Magnets & Power supplies B&Q mag. Other magnets fabricate Field measurement Beam transport and kickers Power supplies R&D Fabrication Beam pipes Fabrication Monitors, Control Fabrication RF System cavity design cavity fabrication HP test HP test Cooling system Install Alignment Install Alignment Install Install cavity install HP&LLRF install DR commissioning

46 Installation Schedule of Belle II

47 Two weeks ago: taking out the SVD2 vertex detector

48 Luminosity prospect Integ grated Lum minosity (ab -1 ) Milestone of SuperKEKB We will reach 50 ab -1 in 2020~ month/year 20 days/month Peak Lum minosity (cm -2 s -1 ) Commissioning starts in 2 nd half of 2014 Shutdown for upgrade

49 Summary B factories have proven to be an excellent tool for flavour physics, with reliable long term operation, constant improvement of the performance, achieving and surpasing design perfomance Major upgrade at KEK in SuperKEKB+Belle II, L x40, construction ti started t The project has a strong European participation (~1/3!), including major responsibilities in several essential subsystems Physics reach updates available Technical design report published Expect a new, exciting era of discoveries, complementary to the LHC

50 Additional slides

51 Funding agencies Financial Oversight Panel BPAC Belle II collaboration Report Oversight MOU Finance Board Spokesperson Project manager Money transfer Purchase req. KEK Accounting office Purchasing office

52 Belle-II Collaboration : LoI for SuperKEKB : KEK Roadmap identified as high priority project at KEK : New collaboration (Belle-II) officially formed 13 countries/region, 43 institutes, ~300 members Separate group/organization from Belle Executive Board (Chair: H. Aihara) Spokesperson: P. Križan Project manager: M. Yamauchi Institutional Board (Chair: L. Piilonen) Physics coordinator: B. Golob Technical coordinator: Y. Ushiroda Software /computing coordinators: T. Hara / T. Kuhr : 7 th Open Collaboration Meeting

53 Physics at a Super B Factory There is a good chance to see new phenomena; CPV in B decays from the new physics (non KM). Lepton flavor violations in τ decays. They will help to diagnose (if found) or constrain (if not found) new physics models. B τν, Dτν can probe the charged Higgs in large tanβ region. Physics motivation is independent of LHC. If LHC finds NP, precision flavour physics is compulsory. If LHC finds no NP, high statistics B/τ decays would be a unique way to search for the >TeV scale physics (=TeV scale in case of MFV). There are many more topics: CPV in charm, new hadrons,

54 Super B Factory Motivation 2 Lessons from history: the top quark Physics of top quark First estimate of mass: BB mixing ARGUS Direct production, Mass, width etc. CDF/D0 Off-diagonal couplings, phase BaBar/Belle V V V V ud V V us V V ub CKM= cd cs cb td V ts V tb Even before that: prediction of charm quark from the GIM mechanism, and 0 its mass from K 0 mixing Recent update of the physics reach with 50 ab -1 : Physics at Super B Factory (Belle II authors + guests) hep-ex > arxiv: