The Belle Experiment at KEKChristoph Schwanda

Institute of High Energy Physics (HEPHY)Austrian Academy of Sciences

Symposium Wissenschaftliche Kooperation Österreich-JapanAustrian Academy of Sciences, November 28, 2014

2© CERN

3

4

© NASA/WMAP

Extensions to the Standard Model

Supersymm

etry

Technicolor

Large Extra Dimensions

Little Higgs

Grand Unification

5

Physics beyond the

Standard Model

Energy Frontier

Precision Frontier

Cosmological Frontier

6

KEK Tsukuba site (Japan)

Linac

KEKB rings (HER+LER)

e+e- ® Y(4S) ® BBe+e- ® t+t-

Belle detector

KEKB/Belle operation (1999-2010):772 million BB events930 million t+t- events

m / KL detection 14/15 lyr. RPC+Fe

CsI(Tl) 16X0

Si vtx. det. 3(4) lyr. DSSD

SC solenoid 1.5T

8 GeV e-

3.5 GeV e+

Aerogel Cherenkov cnt. n=1.015~1.030

Central Drift Chamber small cell +He/C2H5

TOF counter

The Belle detector

7

B factories: a success story

B0→J/ψK0_B0→J/ψK0

Discovery of CP violationin the B meson system (2001)

Confirmation of CKM mechanism

Rate of the decay B0 (B0)

→J/ψK0 as a function of the decay time difference of the two Bs in Y(4S) → BB events

8

9

“… As late as 2001, the two particle detectors BaBar at Stanford, USA and Belle at Tsukuba, Japan, both detected broken symmetries independently of each other. The results were exactly as Kobayashi and Maskawa had predicted almost three decades earlier.”

Past achievements: Vienna key contributions to Belle• Detector contribution– Readout system for the silicon tracker– 110,592 analog readout channels– Worked flawlessly for 7 years

10

• Physics research– Leading the Belle CKM physics group• CKM elements |Vcb| and |Vub|• search for the charged Higgs boson

– Awards• Victor Hess prize of APS (2010)• Best paper award of AAS (2011)

Belle collaboration papers with a Vienna first author:

[PRD 88, 114006 (2013)]PRD 82, 112007 (2010)][PRL 100, 241801 (2008)][PRD 78, 032016 (2008)][PRD 75, 032005 (2007)][PRL 97, 061804 (2006)][PRL 93, 131803 (2004)]

Grants No. P22742, P26794

11

e- 2.6 A

e+ 3.6 A

To get x40 higher luminosity

Colliding bunches

Damping ring

Low emittance gun

Positron source

New beam pipe& bellows

Belle II

New IR

TiN-coated beam pipe with antechambers

Redesign the lattices of HER & LER to squeeze the emittance

Add / modify RF systems for higher beam current

New positron target / capture section

New superconducting /permanent final focusing quads near the IP

Low emittance electrons to inject

Low emittance positrons to inject

Replace short dipoles with longer ones (LER)

KEKB to SuperKEKB

12

The Belle II detector

13

CsI(Tl) EM calorimeter: waveform sampling electronics, pureCsI for endcaps

RPC μ & KL counter: scintillator + Si-PM for end-caps

Time-of-Flight, Aerogel Cherenkov Counter → Time-of-Propagation (barrel), prox. focusing Aerogel RICH (forward)

4 layers DS Si vertex detector → 2 layers PXD (DEPFET) + 4 layers DSSD

Central Drift Chamber: smaller cell size, long lever arm

HEPHY leading design & construction of the SVD• Novel silicon tracking device matched to the

challenging Belle II environment• 1.2 m2 of double-sided silicon detectors• 4 layers covering the radii between

3.8 cm and 14 cm around the interaction region

14

• World’s lowest mass collider detector• Track reconstruction down

to 50 MeV in pt

• Readout electronics for 243k analog channels• Hits measured with O(10 mm) resolution in

space and 3 ns resolution in time• Trigger rates up to 30 kHz

15

Nov. 2014: MoU Austria-KEKon scientific cooperation for Belle II

The Belle II Collaboration

23 countries/regions, 99 institutions 621 collaborators,207 from Europe

• Detector construction• Physics research

16

17

Nov 18, 2011: SuperKEKB groundbreaking

18

19

SuperKEKB/Belle II ScheduleNov. 3, 2014

JFY2018

20182014

JFY2014

2015 2016 2017

JFY2015 JFY2016 JFY2017now

Power restriction in summer

phase 1 phase 2 phase 3Start-up QCS, Belle II install VXD installw/o QCS

w/o Belle IIw/ QCSw/ Belle II (no VXD)

w/ full Belle II

phase 1 phase 2 phase 3Start-up QCS, Belle II install VXD installw/o QCS

w/o Belle IIw/ QCSw/ Belle II (no VXD)

w/ full Belle II

phase 1 phase 2 phase 3SuperKEKB Construction

Start-up QCS, Belle II install VXD installw/o QCSw/o Belle II

w/ QCSw/ Belle II(no VXD)

w/ full Belle II

phase 1 phase 2Start-up QCS, Belle II install

VXD installw/o QCSw/o Belle II

w/ QCSw/ Belle II (no VXD)

JFY2014 Operation budget cut by 12 Oku-Yen

JFY2015 Operation budget under discussion

SuperKEKB Construction

SuperKEKB Construction

SuperKEKB Construction

Power restriction in summer

Power restriction in summer

phase 3

w/ full Belle II

20

Summary

• The Institute of High Energy Physics (HEPHY) of the Austrian Academy of Sciences has a long-standing scientific cooperation with Japan in the field of particle physics

• HEPHY was deeply involved in the Belle experiment (data taking: 1999-2010) and contributed to both to the detector hardware and to the experiments scientific results

• We are now also heavily involved in the Belle II upgrade, assuming the overall responsibility for the Silicon Vertex Detector

• Looking forward to the first Belle II data in 2017!

21

Backup

22

Cabibbo-Kobayashi-Maskawa quark mixing

• W couples to the weakeigenstates

• Charged current processes can change quark flavour

• CKM matrix elements appears at the quark-W vertex

April 9, 2014

23

The CKM unitarity triangle

B ® Xln

CPV in B ® pp, rr, rp

CPV in B ® J/yKsB-/+ ® D(*)K(*)-/+

April 9, 2014