Gary S. Varner, Hawai’i The Belle-II Experiment at SuperKEKB

Gary S. Varner University of Hawai’i at Manoa

Boston (Cambridge), July 26, 2011 Luminosity at the B Factories Gary S. Varner, Hawai’i

Fantastic performance much beyond design values!  Need O(100x) more data Next generation B-factories Gary S. Varner, Hawai’i SuperKEKB  + SuperB

40 times higher luminosity KEKB

PEP-II

 Asymmetric B factories Gary S. Varner, Hawai’i

√s=10.58 GeV + - B e e z ~ c Υ(4s) B Υ(4s) B ~ 200m BaBar p(e-)=9 GeV p(e+)=3.1 GeV =0.56 Belle p(e-)=8 GeV p(e+)=3.5 GeV =0.42

Belle II p(e-)=7 GeV p(e+)=4 GeV =0.28  Full Reconstruction Method Gary S. Varner, Hawai’i • Fully reconstruct one of the B’s to – Tag B flavor/charge – Determine B momentum – Exclude decay products of one B from further analysis

Decays of interest B BXu l , BK  e e+(3.5GeV) (8GeV) BD,  Υ(4S)  B full reconstruction BD etc. (~0.5%)

 Offline B meson beam! Powerful tool for B decays with neutrinos

 “Super” B Factory motivation Gary S. Varner, Hawai’i

For details on physics opportunities: See Kay Kinoshita talk 17:20 B factories  is SM with CKM right? Thursday, July 28 – Section 5I

Super B factories  How is the SM wrong?

 Need much more data (two orders!) because the SM worked so well until now  Super B factory

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 to LHCb and BESIII

Recent update of the physics reach with 50 ab-1 (75 ab-1): Physics at Super B Factory (Belle II authors + guests) hep-ex > arXiv:1002 .5012 SuperB Progress Reports: Physics (SuperB authors + guests) hep-ex > arXiv:1008.1541

 TSUKUBA Area (Belle) High Energy Ring (HER) for Electron

HER LER How to do it? Interaction Region

Low Energy Ring (LER) for Positron Gary S. Varner, Hawai’i F R RF ER RF  upgrade KEKB and Belle RF NIKKO Area OHO Area WIGGLER RF RF WIGGLER

(TRISTAN Accumulation Ring)

e HER + /e - LER Electron Positron

Linac RF RF FUJI Area

7 Strategies for increasing luminosity Gary S. Varner, Hawai’i

-

- (1) Smaller * y “Nano-Beam” scheme (2) Increase beam currents

(3) Increase y Collision with very small spot-size beams

Invented by Pantaleo Raimondi for SuperB 8 KEKB to SuperKEKB

Gary S. Varner, Hawai’i Belle II Collidi ng b unch es

New IR e- 2.6 A

New superconducting New beam pipe /permanent final focusing & bellows e+ 36A3.6 A quads near the IP

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 & New positron target / LER to squeeze the emittance capture section Support Nano-beams

TiN-coated beam pipe Low emittance gun with antechambers Low emittance electrons to inject 9 To get x40 higher luminosity Machine design parameters Gary S. Varner, Hawai’i KEKB SuperKEKB parameters units LER HER LER HER

Beam energy Eb 353.5 8 4 7 GVGeV Half crossing angle φ 11 41.5 mrad

Horizontal emittance εx 18 24 323.2 434.3-464.6 nm Emittance ratio κ 0.88 0.66 0.27 0.25 % * * Beta functions at IP βx /βy 1200/5.9 32/0.27 25/0.31 mm

Beam currents Ib 1.64 1.19 3.60 2.60 A beam-beam parameter ξy 0.129 0.090 0.0886 0.0830 Luminosity L 212.1 x 1034 8108 x 1035 cm-2s-1

• Small beam size & high current to increase luminosity • Large crossing angle • Change beam energies to solve the problem of LER short lifetime

 SuperKEKB luminosity profile Gary S. Varner, Hawai’i

We are here SuperKEKB luminosity profile Goals of Belle II/SuperKEKBII/SuperKEKB

minosity minosity minosity --11 uuuu We will reach 50 ab in 2021 )) 1 --1 Integrated lIntegrated l (ab(ab 9 months/year 20 days/month Commissioning starts y y tttt in late 2014. Shutdown

)) Y. Ohnishi 1

--1 for upgrade ss 2 --2 ak luminosiak luminosi mmmm PePe (c (c Year  Requirements for the Belle II detector

Gary S. Varner, Hawai’i BELLE Critical issues at L= 8 x 1035/cm2/sec

 Higgg(her background ( 10-20) - radiation damage and occupancy - fake hits and pile-up noise in the EM Calorimeter  Higher event rate ( 10) - higher rate trigger, DAQ and 10 cm computing BELLE  Special features required -low p  identification  s recon. eff. - hermeticity   “reconstruction”

Resulflt: significant upgrad e

 10 cm Belle II detector upgrade Gary S. Varner, Hawai’i CsI(Tl) EM calorimeter: 7.4 m RPC m & KL counter: waveform sampling scintillator + Si-PM electronics, pure CsI for end-caps for end-caps

4 layers DS Si Vertex Detector → 2 layers PXD (DEPFET) , 505.0 m 4 layers DSSD

Time-of-Flight, Aerogel Cherenkov Counter → CtlDiftChbCentral Drift Chamber: Time-of-PiPropagation counter smaller cell size, (barrel), long lever arm prox. focusing Aerogel RICH (forward)  Belle II Collaboration Gary S. Varner, Hawai’i 15 countries, ~60 institutions ~400 collaborators

Belle II web page: TDR http://b2comp.kek.jp/~twiki/pub/Organization/B2TDR/B2TDR.pdf  Belle II in comparison with Belle

Gary S. Varner, Hawai’i

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 Parameters are preliminary KLM: RPC  Scintillator +SiPM (end‐caps)  Interaction Region Design Gary S. Varner, Hawai’i

16 Detector Performance Improvements

Gary S. Varner, Hawai’i

• Many sub-detector upgrades targeted to handling higher trigger, event and background rates

• DEPFET Pixel sensors (PXD) for the two innermost silicon vertexing layers (L1+L2)

• Advanced particle identification detectors

• Waveform sampling, multi-event buffering, upgraded data acquisition: data rates to disk comparable to LHC experiments  DEPFET pixels for Belle II

Gary S. Varner, Hawai’i

radius pixel thickness Layer 1 r = 14mm 50x50m2 75m(0.18%X0) Layer 2 r = 22mm 50x75m2 75m

total of 8 M pixels

Mechanical mockup

Power consumption in sensitive area: 0.1W/cm² => air-cooling sufficient  Expected vertexing improvement Gary S. Varner, Hawai’i

b   a  p sin 

Pixel detector closer

] ] to the beam pipe Less Coulomb m m

 scattering  [ [ Belle   Belle II’ Belle II

3/2 p [GeV/c] 5/2 0 1.0 2.0 sin( 0 1.0 2.0 psin( [GeV/c] ) ) Closest approach Z-resolution

19 Particle Endcap PID: Aerogel RICH (ARICH) 200mm Identification Gary S. Varner, Hawai’i Barrel PID: Time of Propagation Counter (TOP)

Quartz radiator Aerogel radiator FiFocusing m irror n~1.05 Small expansion block Hamamatsu HAPD Hamamatsu MCP-PMT (measure t, x and y) + new ASIC

Aerogel ra diat or HHAPDdHamamatsu HAPD + readout

200

 Expected PID improvement Gary S. Varner, Hawai’i ficiency ff

K e • 2 GeV/c • 3 GeV/c • 4 GeV/c

• 2 GeV/c • 3 GeV/c • 4 GeV/c ke rate aa f 

Belle PID iTOP only (no dE/dx) 21 Expected Performance

(Luminosity gain) Gary S. Varner, Hawai’i

No upgrade Upgrade BAD GOOD

FWD ACC dE/dx As good as A- BRL only only Belle RICH

TOF, Completely No upgrade No –74% –69% –68% –62% BAD dE/dx NA different game TOF NA –41% –35% –32% –22% with excellent

As good PID detectors as Belle –10% –4% 0% (definition) +12% Upgra GOO D d e iTOP +45% +51% +60% +83%

Example mode:



22 Construction Schedule of SuperKEKB/Belle II

Gary S. Varner, Hawai’i FY2009 FY2010 FY2011 FY2012 FY2013 FY2014 Linac e+ new matching & L-band acc. R&D Construction e+ beam commissioning RF-gun &l& laser syst em A1 gallery extension move Design study to A1 Commissioning at test stand e- beam commissioning

Damping Ring Facilities Tunnel construction Building DR Components R&D, Design construction commissioning Mass Fabrication Installation

Main Ring Facilities Building construction

Components R&D, Design MR Mass Fabrication commissioning Installation

BEAST II Belle II Detector Ad-hoc detector for MR commissioning

R&D Mass Production Construction Ready to Roll-in Itllti(KLM)Installation (KLM) Itllti(EInstallation (E-cap) Belle roll-out Installation (Barrel) in Dec. 2010 Cosmic Ray Test 23 Deconstructing to start Belle II upgrade

Gary S. Varner, Hawai’i

Early November 2010: extracted the SVD2 – vertex detector

Belle Detector Roll-out: Dec. 9, 2010 EdEnd-caps, CDC, B-ACC, TOF extract ion: by en d o f Jan. 2011 Ready for new construction to start…  The Earthquake Gary S. Varner, Hawai’i

M22 bolts!! As is well known, Japan suffered a terrible earthquake and tsunami on March 11, which has caused tremendous damage, especially in the Tohoku area. Fortunately, all KEK personnel and users were safe. The injection linac did suffer significant but manageable damage, and repairs are underway. The damage to the KEKB main rings appears to be less serious, though non -negligible. No serious damage has been reported so far at Belle. Further investigation is necessary. We would like to convey our deep appreciation to everyone for your generous expressions of concern and encouragement.  KEKB/Belle status Gary S. Varner, Hawai’i Fortunately enough: • KEKB stopped operation in July 2010, and the low energy ring was to a large extent disassembled • Belle was rolled out its parked position

The 1400 tons of Belle moved by ~6cm (most probably by 20cm in one direction, and 14cm back)...

We are checking the functionality of the Belle spectrometer (in particular the CsI calorimeter), so far checks out OK in LED and cosmic ray tests

The lab (Tsukuba campus) has to a large extent recovered from the earthqq,uake, back to normal op eration – veryyp little impact on the upg rade schedule

 Summary Gary S. Varner, Hawai’i • B factories have proven to be an excellent tool for flavor physics, with reliable long term operation, consistent improvement of the performance, achieving and surpassing design performance  Super B Factories look to extend to Beyond Standard Model • Major upgrade of the Belle detector at KEK in 2010-14  Interesting and novel new subdetectors, construction started • Expect a new, exciting era of discoveries, complementary to the LHC

 Back-up slides Gary S. Varner, Hawai’i

 B-factory Detectors –

a huge success! Gary S. Varner, Hawai’i

• Measurements of CKM matrix elements and angles of the unitarity triangle • Observation of direct CP violation in B decays • Measurements of rare decays (e.g., B, D) • bs transitions: probe for new sources of CPV and constraints from the bsbranching fraction

• FdForward-bkbackward asymmetry (AFB)i) in bsll hbhas become a powerfull tool to search for physics beyond SM. _B0 tag B0 tag • Observation of D mixing • Searches for rare decays • Observa tion of new hadrons

 Physics at a Super B Factory Gary S. Varner, Hawai’i • There is a good chance to see new phenomena; – CPV in B decays from the new physics (non KM). – Lepton flavor violations in  decays. • They will help to diagnose (if found) or constrain (if not found) new physics models. •B, D can probe the charged Higgs in large tan region. • Physics motivation is independent of LHC. – If LHC finds NP, precision flavour physics is compulsory . – If LHC finds no NP, high statistics B/ 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, …

Recent update of the physics reach with 50 ab-1 (75 ab-1): Physics at Super B Factory (Belle II authors + guests) hep-ex > arXiv:1002.5012 SuperB Progress Reports: Physics (SuperB authors + guests) hep-ex > arXiv:1008.1541