The Belle II Project

B. Golob, Belle II 1/23Epiphany Conference, Cracow, Jan 2012

Boštjan GolobUniversity of Ljubljana/Jožef Stefan

Institute & Belle/Belle II Collaboration

The Belle II Project

University of Ljubljana

“Jožef Stefan” Institute

Epiphany Conference, Cracow, January 2012

Introduction PID

Accelerator Calorimeter

Vertex General

Introduction

Accelerator

Detector Vertex physics example PID physics example Calorimeter physics example

General requirements


Introduction

Quest for NP...

....consists of energy frontier direct observation of new particles & processes using highest achievable energies

intensity frontier indirect observation of NP effects on (rare) known processes

(cosmic frontier)

Introduction PIDAccelerator Calorimeter

Vertex General

bližina otoka Veli Drvenik, sept. 2011

Intensity frontier

Energy frontier


Introduction

Quest for NP LHC at the energy frontier

V. Sharma, LP11 conference

95% C.L. exclusion limits in mass SUSY plane

H. Bachacou, LP11 conference

95% C.L. exclusion limits on MSSM A0

1 TeV

SUSY in the simplest formsseems to be excluded

gq ~~


Vertex General


Introduction

Quest for NP B factories, LHCb, ... at the intensity frontier

B mesons sector D mesons sector

indCP

dirCPCPCP a

taAKKA

)()(

b =

CKM Fitter, Summer 2011 HFAG, December 2011

Hints of deviations from SM at few s level


Vertex General

direct measurement

indirect determination


Introduction

Quest for NP Intensity frontier requirements for future facilities (quark sector)

• s1/N O(102) higher luminosity

• complementarity to other intensity frontiers experiments (LHCb, BES III, ....);

• accurate theoretical predictions to compare to

NP flavor violating couplings( 1 in MFV)

NP

reac

h in

term

s of

mas

s

Terra Incognita

Illustrative reach of NP searches


Vertex General


Introduction

Accelerator “B-Factory”, KEKB @ KEK

KEKB:

e- (HER): 8.0 GeVe+ (LER): 3.5 GeV

crossing angle: 22 mrad

ECMS=M(U(4S))c2

dNf/dt = s(e+e-→f) L

Tokyo (40 mins by Tsukuba Exps)

Belle

HER

LER

Ldt = 1020 fb-12010

1999

acceleratorinstitute

e-

e+

(1.02 ab-1)


Vertex General


Introduction

s(e+e- → c c) 1.3 nb (~1.3x109 XcYc pairs)

”continuum” production

“on resonance” productione+e- → U(4S) → Bd

0Bd0, B+B-

s(e+e- → BB) 1.1 nb (~109 BB pairs)

Belle Ldt 1020 fb-1

Accelerator “B-Factory”, KEKB @, KEK

s(e+ e

- →ha

dron

i) [n

b]

b

bu,d

b

b

u,d

U(4S)

Bd0, B+

Bd0, B-

energ. thresholdfor BB production

g* c

c

e-

e+

hadrons

hadrons


Vertex General

running at Y(nS), e.g. Y(5S) (BsBs)


Accelerator

SuperKEKB sx~100mm,sy~2mmsx~10mm,sy~60nm

e-

e+

Nano beams design(P. Raimondi)

yRR

βξI

erL L

*y

y

x

y

e ssg

*

*

12

small by*large y (by*/ey) small ey

hourglass effect small bx*

increase I

b*: beta-function (trajectories envelope) at IPy: beam-beam parameter

L[s-1cm-2]

∫L dt[ab-1]

design L=8·1035 s-1cm-2

current B factories∫L dt=10 ab-1 (2018)

∫L dt=50 ab-1 (2022)


Vertex General

KEKBSuperKEKB


Accelerator

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)

Super KEKBe+

e-


Vertex General


Detector

CsI(Tl) EM calorimeter: waveform sampling electronics, pure CsI for end-caps

4 layers DSSD → 2 layers PXD (DEPFET) + 4 layers DSSD

Central Drift Chamber: smaller cell size, long lever arm

7.4 m

7.1 m

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

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

1.5 m

3.3 m

Belle II


Vertex General


Vertex detector

00

10

1+23

456

[cm] layers

[cm]

20

-10-20-30 10 20 30 40

PXD+SVD Belle IIr [cm] SVD Belle

z [cm]sBelle Design Group, KEK Report 2008-7

DSSD’s

pixels

z [cm]

DEPFET matrix

DCDBR/O chip

Switcher control

chip

prototype DEPFET sensor

DEPFET mockup

Si Vertex Det.

Belle

Belle II

10 mm

20 mm

z impact parameter resolution

pb*sin5/2(q) [GeV/c]


Vertex General


t-dependent CPV

B → K* (→KS0)g t-dependent CPV

SM: SCP

K*g -(2ms/mb)sin2f1 -0.04

Left-Right Symmetric Models: SCP

K*g 0.67 cos2f1 0.5

SCPKs0g = -0.15 ±0.20

ACPKs0g = -0.07 ±0.12 HFAG, Summer’11

(~SM prediction)

D. Atwood et al., PRL79, 185 (1997)B. Grinstein et al., PRD71, 011504 (2005)

s(SCPKs0g)= 0.09 @ 5 ab-1

0.03 @ 50 ab-1

)]cos(

)sin(1[4

);(/||

0

tmA

tmSetfBP

fCP

fCP

t

t-dependent decays rate of B → fCP; S and A: CP violating parameters

5 ab-1

50 ab-1


Vertex General


Proximity focusing Aerogel RICH(endcap)

PID

Time Of Propagation counter (barrel)

partial Cerenkov ring reconstruction from x, y and t of propagation

prototype quartz bar

Hamamatsu 16ch MCP-PMT

Aerogel radiator

Hamamatsu HAPD

Cherenkov

photon

200mm

n~1.05

Hamamatsu HAPD

Aerogel


Vertex General

xy


Direct CPV

DCPV puzzle: tree+penguin processes, B+(0) →K+0()

AK= A(K+ -)- A(K+ 0)= -0.127±0.022

model independent sum rule:

A(K0+)=0.009 ±0.025A(K+0)=0.050 ±0.025A(K+-)=-0.098 ±0.012A(K00)=-0.01 ±0.10

M. Gronau, PLB627, 82 (2005); D. Atwood, A. Soni, PRD58, 036005 (1998)

HFAG, Summer’11

Belle II 50 ab-1

A(K00)

A(K0+)

sum rule

dA(K + 0)

measured (HFAG)

expected(sum rule)

Belle, Nature 452, 332 (2008), 480 fb-1

misidentif. bkg.

B0 →K+


Vertex General

P. Chang, EPS’11


EM Calorimeter

ECL (barrel):

new electronics with2MHz wave form sampling

ECL (endcap):

pure CsI crystals;(may be staged)

faster performance and better rad. hardness than Tl doped CsI

t

ECLsignal

t

ECLsignal

amplitude time sampling

2x improveds at 20x bkg.


Vertex General

trigger trigger

off-timebkg. signal


Emiss measurements

B n, hnn, ...

fully (partially) reconstruct Btag;reconstruct h from Bsig→hnn or (→ hn)n;no additional energy in EM calorim.; signal at EECL~0;

Btag full reconstruction:NeuroBayes;TOP detector;ECL, increased background;

Example of B hnn measurement:

Missing E(n)

Bsig → n candidateevent

Bsig

Btag

-- exp. signal (20xBr) exp. bkg. (scaled to sideband)

Belle, PRL99, 221802 (2007), 490 fb-1

hadr. tagsignalregion


Vertex General

B(B0 →K*0 nn) < 3.4 ·10-4 @ 90% C.L.


Emiss measurements

B hnn

BsigBtag (hnn)(Xln) semil. tag (hnn)(X) hadr. tag

B(B+ K(*)+nn) can be measured to ±30% with 50 ab-1;

limits on right-handedcurrents

222

2

)tan1()(

)(

bn

n

H

BSM

mmB

B

W. Altmannshofer et al., arXiv:0902.0160

SM


Vertex General


SuperKEKB requirements

• O(102) higher luminosity SuperKEKB will deliver 50 ab-1



∫L dt[ab-1]

current B factories

∫L dt=50 ab-1 (2022)

2010 2012 2014 2016 2018 2020 2022


Vertex General



• O(102) higher luminosity



G. Isidori et al., Ann.Rev.Nucl.Part.Sci. 60, 355 (2010)Super B factory

LHCb

K experiments


Vertex General

B(B →Xsg) 6% Super-BB(B →Xdg) 20% Super-BS(B →rg) 0.15 Super-BB( →mg) 3 ·10-9 Super-B (90% U.L.)B(B+ →Dn) 3% Super-BB(Bs →gg) 0.25 ·10-6 Super-B (5 ab-1) sin2qW @ U(4S) 3 ·10-4 Super-B


SuperKEKB requirementsIntroduction PIDAccelerator Calorimeter

Vertex General

Methods and processes where Super B factory can provide important insight into NP complementary to other experiments: (shown are expected sensitivities @ 50 ab-1)

Emiss:B(B→ n), B(B → Xcn), B(B → hnn),... ±3% ±3% ±30%

Inclusive: B(B → sg), ACP(B → sg), B(B → sll ), ... ±6% ±5 ·10-3 ±1 ·10-7

Neutrals:S(B → KS0g), S(B → h’ KS), S(B → KSKSKS), B( → mg), B(Bs → gg), ... ±0.03 ±0.02 ±0.03 ±3 ·10-9 ±3 ·10-7 Detailed description of physics program at Super B factories at:A.G. Akeroyd et al., arXiv: 1002.5012 B. O’Leary et al., arXiv: 1008.1541



A.G. Akeroyd et al., arXiv:1002.5012

contours of S(KS0g)

Example of complementarity: MSSM searches

Belle II constraints shown @ 5 ab-1

LHCb: Br(Bs m+m-)~ (4-5)x10-9 (@ 3 fb-1)

S(KS0g) ~ -0.4±0.1S(KS0g) ~ 0.1±0.1

TeVmm gq 1~~

Belle II/LHCb combination:stringent limits on Re(dd

RL)23 , tanbtan b

Re(dd

RL)

23


Vertex General



• O(102) higher luminosity



G. Isidori et al., Ann.Rev.Nucl.Part.Sci. 60, 355 (2010)

theory uncertaintymatches the expectedexp. precision

theory uncertainty willmatch the expectedexp. precision with expected progress in LQCD


Vertex General


SummaryIntroduction PIDAccelerator Calorimeter

Vertex General

• The SuperKEKB and Belle II project approved by the Japanese government

• Truly int. coll. with strong European participation

• Groundbreaking ceremony in November last year

• Both accelerator upgrade and detector re-building are well on track

• SuperKEKB will provide 50 ab-1 by 2022, Belle II detector with equal or better performance than Belle under higher backgrounds

• Next collaboration meeting: March 2012, open to everyone

Documents

The Belle II Project