the belle ii project
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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
B. Golob, Belle II 2/23Epiphany Conference, Cracow, Jan 2012
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
B. Golob, Belle II 3/23Epiphany Conference, Cracow, Jan 2012
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 ~~
Introduction PIDAccelerator Calorimeter
Vertex General
B. Golob, Belle II 4/23Epiphany Conference, Cracow, Jan 2012
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
Introduction PIDAccelerator Calorimeter
Vertex General
direct measurement
indirect determination
B. Golob, Belle II 5/23Epiphany Conference, Cracow, Jan 2012
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
Introduction PIDAccelerator Calorimeter
Vertex General
B. Golob, Belle II 6/23Epiphany Conference, Cracow, Jan 2012
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)
Introduction PIDAccelerator Calorimeter
Vertex General
B. Golob, Belle II 7/23Epiphany Conference, Cracow, Jan 2012
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
Introduction PIDAccelerator Calorimeter
Vertex General
running at Y(nS), e.g. Y(5S) (BsBs)
B. Golob, Belle II 8/23Epiphany Conference, Cracow, Jan 2012
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)
Introduction PIDAccelerator Calorimeter
Vertex General
KEKBSuperKEKB
B. Golob, Belle II 9/23Epiphany Conference, Cracow, Jan 2012
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-
Introduction PIDAccelerator Calorimeter
Vertex General
B. Golob, Belle II 10/23Epiphany Conference, Cracow, Jan 2012
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
Introduction PIDAccelerator Calorimeter
Vertex General
B. Golob, Belle II 11/23Epiphany Conference, Cracow, Jan 2012
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]
Introduction PIDAccelerator Calorimeter
Vertex General
B. Golob, Belle II 12/23Epiphany Conference, Cracow, Jan 2012
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
Introduction PIDAccelerator Calorimeter
Vertex General
B. Golob, Belle II 13/23Epiphany Conference, Cracow, Jan 2012
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
Introduction PIDAccelerator Calorimeter
Vertex General
xy
B. Golob, Belle II 14/23Epiphany Conference, Cracow, Jan 2012
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+
Introduction PIDAccelerator Calorimeter
Vertex General
P. Chang, EPS’11
B. Golob, Belle II 15/23Epiphany Conference, Cracow, Jan 2012
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.
Introduction PIDAccelerator Calorimeter
Vertex General
trigger trigger
off-timebkg. signal
B. Golob, Belle II 16/23Epiphany Conference, Cracow, Jan 2012
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
Introduction PIDAccelerator Calorimeter
Vertex General
B(B0 →K*0 nn) < 3.4 ·10-4 @ 90% C.L.
B. Golob, Belle II 17/23Epiphany Conference, Cracow, Jan 2012
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
Introduction PIDAccelerator Calorimeter
Vertex General
B. Golob, Belle II 18/23Epiphany Conference, Cracow, Jan 2012
SuperKEKB requirements
• O(102) higher luminosity SuperKEKB will deliver 50 ab-1
• complementarity to other intensity frontiers experiments (LHCb, BES III, ....);
• accurate theoretical predictions to compare to
∫L dt[ab-1]
current B factories
∫L dt=50 ab-1 (2022)
2010 2012 2014 2016 2018 2020 2022
Introduction PIDAccelerator Calorimeter
Vertex General
B. Golob, Belle II 19/23Epiphany Conference, Cracow, Jan 2012
SuperKEKB requirements
• O(102) higher luminosity
• complementarity to other intensity frontiers experiments (LHCb, BES III, ....);
• accurate theoretical predictions to compare to
G. Isidori et al., Ann.Rev.Nucl.Part.Sci. 60, 355 (2010)Super B factory
LHCb
K experiments
Introduction PIDAccelerator Calorimeter
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
B. Golob, Belle II 20/23Epiphany Conference, Cracow, Jan 2012
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
B. Golob, Belle II 21/23Epiphany Conference, Cracow, Jan 2012
SuperKEKB requirements
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
Introduction PIDAccelerator Calorimeter
Vertex General
B. Golob, Belle II 22/23Epiphany Conference, Cracow, Jan 2012
SuperKEKB requirements
• O(102) higher luminosity
• complementarity to other intensity frontiers experiments (LHCb, BES III, ....);
• accurate theoretical predictions to compare to
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
Introduction PIDAccelerator Calorimeter
Vertex General
B. Golob, Belle II 23/23Epiphany Conference, Cracow, Jan 2012
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
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