B-Factories: Physics Reach
-
Upload
hilda-wilkins -
Category
Documents
-
view
34 -
download
0
description
Transcript of B-Factories: Physics Reach
B-Factories: Physics Reach
Luminosity
CPV and CKM
Rare B decays
Conclusions
Livio Lanceri – Univ. and INFN TriesteINFN-CSNI – LNF, February 4, 2003
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 2
Discovery potential at the B factories• CKM and Unitarity Triangle
– SM predicts a pattern of CPV, from phase in the CKM matrix– B factories can measure both angles and sides of the
Unitarity Triangle– New phases from New Physics may reshape the UT
• Rare B Decays– CKM suppressed (tree b u), Radiative Penguins (QCD, EM,
EW), leptonic B decays– Common feature (Penguins, leptonic): New Physics
signatures from rates and asymmetries (new virtual particles in the loops)
• Charm, tau– Examples: D mixing and lepton number violating decays– Very small in SM windows for New Physics
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 3
Asymmetric B factories optimized for measurements of time-dependent CP violating asymmetries
OK also for other measurements (rare B decays, …)Open trigger! No B physics losses at trigger levelHigh efficiencies, small bkgdUnique tool at B factories: exclusive B tagging with fully rec. B (“single B
beam”)Luminosity is a key factor
Experimental ingredients
z(CP)z(tag)
Inclusive tag (lepton, K, …): tag(1-2w)2 28%
00)4( BBsee
c
tagzCPzt
)()(
rec 1540%
(Exclusive tag: tag 0.10.2%)
28.0;nb1 had
bbbb
< z > 260 mz (RMS) 190 m
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 4
B-Factories: experiments and luminosityBABAR/PEP-II• Record peak luminosity:
– 4.6 x 1033cm-2s-1 (~5 BB/s)
• max lumi/24h: 303 pb-1
• total recorded lumi to date: ~0.1 ab-1 (~10% off-peak)
• Restarted end Nov.2002 after 4 months shutdown (Forward IFR upgrade)
Belle/KEK-B• Record peak luminosity:
– 8.2 x 1033cm-2s-1 (~8 BB/s)
• max lumi/24h: 433 pb-1
• total recorded lumi to date: ~0.1 ab-1 (~10% off-peak)
• Restarted in January 2003 after vacuum loss forced stop in December
c.f. integrated luminosity for
•Argus (1983-1987): ~100 pb-
1
•CLEO (1981-2000): ~16 fb-1
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 5
0
200
400
600
800
1000
1200
Year
Inte
gra
ted
Lu
min
osi
ty (
fb-1
)
0
5
10
15
20
25
30
Pe
ak L
um
ino
sity
[1
0**3
3]
Yearly Integrated Luminosity [fb-1]
Cumulative Integrated Luminosity [fb-1]
Peak Luminosity [10**33]
Yearly Integrated Luminosity [fb-1] 3 23 41 39 62.6 66.1 120.1 151 160.1 217 216
Cumulative Integrated Luminosity [fb-1] 3 26 67 106 168.6 234.7 354.8 505.8 665.9 882.9 1098.9
Peak Luminosity [10**33] 1 2 4.4 5 7.5 10 13 16 20 22 25
1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
PEP-II without upgrades
0.5 ab-1
2006
1.6 x 1034
integrated
peak
2009
1.1 ab-1
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 6
PEP-II upgrade scenariosFrom J.Seeman/SLAC
New IR, present rings New IR, New LER, Constant LER injection
New IR, New rings, Constant injection
# bunches 1700 3400 3400 Beam currents HER: 2A, LER: 4.5A HER: 2A, LER: 24.5A HER: 8.5A, LER:24.5A IP functions x: 18cm, y:0.45/0.5cm x: 15/23cm, y: 0.4cm x: 15cm, y: 0.15cm Beam-beam 0.075 0.075 0.112 Luminosity (cm-2 s-1) 4 1034 1 1035 1 1036
NO
(Super-KEKB?)
SuperPEP/SuperBaBar
Year 20...?New collider,(and new detector…)Snowmass: 370M$
Minimal upgrade
Feasible from 2005Shut-down 3 months0.40.5 ab-1/yearLimited cost
2ab-1
in 2009
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 7
Path to higher PEP-II luminosity
Luminosity 4.6E331E34 2E34 4E34 UnitsI+ 1800 2700 3600 4500 mAI- 950 1400 1760 2000 mABeta y* 11.5 9 7 4.5 mmBeta x* 50 50 50 50 cmBunch Length 1.3 1.0 0.8 0.5 cm# bunches 792 1300 1500 1600Vert. Emitt. 2.5 1.4 1.1 0.7 nmHoriz. Emittance40/50 30/45 32/47 40/48 nm (+/-)Crossing angle 0 0 0 ~+/-8 mradTune shifts (x/y) 7.5/4.58.0/5.78.2/6.08.4/6.3x100Number RF stations 7 10 13 15Date hardware ready Jan 02 Dec 02Dec 04Nov 05Date for luminosity Jun 02 July 03 Dec 05Dec 06
(J.Seeman, BaBar Collaboration meeting, Sept.2002)
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 8
For the 4x1034 PEP-II upgrade:We studied the physics reach in some channels for:
0.5 ab-1 (2006), 2.0 ab-1 (end of the decade)
And: Interest/need of an accompanying BaBar detector upgrade ?
(Conclusion: only Barrel IFR)
Most extrapolations reported here come from the preliminary report of the TF
BaBar Long Term Planning TF
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 9
EoI (January 2002): Super KEK-B, L = 1035cm-2s-1
- LER: e- , I = 10A; HER: e+, I = 3A Linac upgrade (e- e+)
- Vacuum system (ante chambers); RF system (52 cavities, 12SC)
- 15 mrad crossing, final focussing
Total cost (KEK-B + Belle): 400 M$
EoI preliminary plan:
Present plans: … ??Workshop at KEK, Feb.2003
What about KEK-B/Belle upgrades ?
year activity By mid 2006 500 fb-1 mid 2002 - mid 2006 Construction mid 2006 - 2007 Installation 2008 Commissioning > 2008 1 ab-1 / year
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 11
CPV in mixing-decay interference direct CPV
dN exp(–|t|/B) ( 1 ± D (S sin(mt) - C cos(mt)) ) R
CP asymmetry: Time Dependence
2
2
21
1
1
2
CS
Amplitude ratio B0fcp/B0fcp
CP eigenvalueMi
tdtb
tdtb eVV
VV
p
q 2
*
*
B mixing
Measured from data (Flavour sample)!D mis-tag dilutionR time resolution
Flavour tag
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 12
BaBar, sin2results
1
1
CP
CP
sccb
sin2 = 0.741 0.067 0.034sin2 = 0.741 0.067 0.034
sin2 = 0.755 0.074
sin2 = 0.723 0.158
12609.025.098.013.043.031.0
20303.022.010.003.034.002.0
4009.041.038.016.049.005.0
5109.019.02sin
**
0
0
52.050.0
0
DD
CSK
CSJ
K
S
S
030.0051.0948.0
2sin
Charmonium modes
Modes with Penguins Yield
2sinS in Standard Model
on-peak: 81.9 fb-1
off-peak: 9.6 fb-1
89 M BB pairs
tagged CP sample: 2631flavor sample: 25375
(pure Penguin!)
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 13
BaBar, sin2systematics decays with charmonium:
0.034Total
0.003md
0.004B lifetime
0.010Fit bias correction
0.012Signal Dilutions
0.017t meas. and RF
0.015Klong BG
0.017
0.008
CP and Mix BG
DCS decays, tag side
sin2Source
0.004
0.008
0.003
0.010
0.010
0.003
0.003
0.003
0.018
Asymptotic
Using onlylepton tags:
0.01
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 14
sin2: projected errors (BaBar)• Extrapolated statistical and systematic
uncertainties
Statistical uncertaintyFor “golden” modes only
Param. Channel (stat)/(syst) 0.08 ab-1
(stat)/(syst) 0.5 ab-1
(stat)/(syst) 2.0 ab-1
sin2 Im(+) S S S
J/KS Golden D*D* J/0 KS ’ KS
0.08 / 0.03 0.07 / 0.03 0.43 / 0.13 0.49 / 0.16 0.50 / 0.09 0.34 / 0.03
0.037 / 0.018 0.031 / 0.018 0.16 / 0.07 0.20 / 0.20 / 0.14 /
0.018 / 0.018 0.015 / 0.018 0.08 / 0.03 0.10 / 0.10 / 0.07 /
21 L1
syststat ab2at L
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 15
sin2eff from B0+-
b
d d
ud
u
+
-
B0
Mixing + T:
b
d d
d
u
u -
+
t
B0
P:
2 1 /
1 /
2effsin(
sin(
)1 2
)
i i
i i
P T e e
P T e e
ie
C
C
S
Observables in +-CP asymmetry (time-dependent) Extra weak phase –
strong phase , and |P/T|, modify by
eff 22 : from isospin analysis
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 16
BaBar and Belle: S and C
With incomplete information
(no isospin analysis):• Measure S and Cfrom both
sinmt and cosmt terms .
• Compare with predicted S and Cvalues for given , , |P/T|, and . Assume for instance:
22
3021
28.0/
26
)97(
TP
cf. Gronau and Rosner, Phys. Rev. D65, 093012 (2002)
BABAR
Belle 1
Belle 2
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 17
Results (0.08 ab-1)
Param. Channel (stat)/(syst) 0.08 ab-1
(stat)/(syst) 0.5 ab-1
(stat)/(syst) 2.0 ab-1
S C
+-
0.34 / 0.05 0.25 / 0.04
0.12 / 0.03 0.10 / 0.03
0.06 / 0.05 /
Results and extrapolations for
sin2eff
Extrapolated errors (BaBar)
Param. BaBar Belle S C
0.02 0.34 0.05 -0.30 0.25 0.04
-1.23 0.41 (+ 0.05-0.07) -0.77 0.27 0.08
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 18
sin2: isospin analysis (Gronau & London)
Mode Yield BR (10-6) A
B→
B →
2321125 10
1.00.95.5 0.6
0.180.170.03 0.02
eff 22
10923
)%90(6.3 CL6.03.0
7.06.06.1
Need flavor tagged rates for
+-, 0, 00
BaBar:
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 19
Upper bounds on = 2eff-2
0
0002
BF
BFsin
B
B
Grossman-Quinn bound: BaBar, present data:051
BaBar, extrapolations:vs BF(00), at fixed Luminosity
Small gainwith lumi
Most powerful at small BF
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 20
Isospin analysis: projections - 1• Sensitivity to : toy MC with BaBar detector
• Assumptions (example):
L = 0.5 ab-1 L = 2.0 ab-1
BR(B) = 4.1x10-6
BR(B0) = BR(B0) = 4.7x10-6
NB: 4-fold ambiguity !
<BR(B)> = 2.0x10-6
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 21
Isospin analysis: projections - 2• BaBar sensitivity on : summary
– (4-fold ambiguity not included)
• Assumptions: 00 reconstruction efficiency: rec = 0.18– For each B tagging category:
• Tagging performance , D = 1-2w• Bkgd effective cross sect. B (106)
Model BF 106 B 00
BF 106 Bbar 00
() 0.5 ab-1
() 2.0 ab-1
() 10 ab-1
A B C (no bkgd) D
2.5 1.5 2.5 0.6
1.5 0.5 1.5 0.4
0.409 0.452 0.286 0.436
0.177 0.258 0.106 0.316
0.075 0.132 0.045 0.175
Tag
D B
1 0.09 0.93 2.0
2 0.16 0.82 4.0
3 0.20 0.56 5.0
4 0.20 0.41 6.0
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 22
Quasi-2-body B0 analysis
3433413
N
Acp
0.080.080.22 ( ) 0.07( )CPA stat syst
0.080.080.22 ( ) 0.07( )CPA stat syst
0.180.19
0.250.25
0.45 ( ) 0.09( )
0.16 ( ) 0.07( )
C stat syst
S stat syst
0.180.19
0.250.25
0.45 ( ) 0.09( )
0.16 ( ) 0.07( )
C stat syst
S stat syst
hep-ex/0207068
81.9 fb-1
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 23
3-body (+-0) Dalitz analysis for
B0+ – - B00 0 Interference
Region
B0+ – - B0 – + Interference
Region
00
00
, ,
, ,
A A A
A A A
11 parameters (“fundamental”):
remove overall phase & normalization: 9 parameters
00, , , , ,T P T P T
Suffers from mirror solutions
No mirror solutions. Does not depend on particular weak phase decomposition
10 parameters (“amplitudes”):
remove overall phase & normalization: 8 parameters
obtain fundamental parameters from subsequent fit.
…work in progress
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 24
at the B factories• sin(2) from fully/partially reconstructed B
D(*)– Analysis in progress
• Rates and asymmetries in B K, KK– Require theoretical assumptions
• Promising developments: 3-body decays, Dalitz analysis (work in progress)– B D(*)K(*), D(*)Ks, DKs, D(*)K(*), …
• Most advanced analysis in BaBar: B-D0(CP)K-
– Sensitivity extrapolations from preliminary results
0.1.2sin
0.1.2sin
yy
xx
81.2 fb-1 ev.897195
ev.1008058*
D
D
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 25
from B-D0(CP)K-
)(21000 DDD 1||)(
0 ieAKDBA
ii eeAKDBA 2||)( 0
)( *uscbVV
)( *csubVV
(Gronau-London-Wyler)
)cos(2
1
)(
)( 2
0
11
rr
KDB
KDBn
)cos(2
1
)(
)( 2
0
11
rr
KDB
KDBp
)cos(2
1
)(
)( 2
0
22
rr
KDB
KDBn
)cos(2
1
)(
)( 2
0
22
rr
KDB
KDBp
Observables: n1, p1, n2, p2
Theor. parameters: , r,
)1.0(
)(
)(
0
0
O
KDBA
KDBAr
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 26
r=0.2 (2ab-1), sin2fit: sin2
from B-D0(CP)K-: projections
Recent experimental results (BaBar)
Toy MC projections:(Fit unreliable for r = 0.1)
02.029.002.1)(
)(
0
11
KDB
KDBn
)02.026.072.0()(
)(
0
11
KDB
KDBp
r=0.3 (0.5 ab-1), sin2fitsin2
08.023.017.0 CPA
ACP=0.174 0.031
r=0.2 =60o =30o
(2ab-1)
KKD0500
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 28
|Vub| from fully tagged SL decays
Brecoil
BrecoD(*)
Y(4S) l
Xu
Semileptonic decayson the recoil of fully rec. B (~1KB0 /fb-1,~2KBch. /fb-1)
To separate bulMX (< MD)( ~ 60-80%)(or other variables:P*l, q2)
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 29
projected errors for |Vub|
Selection:One B reconstructed in D(*)XLepton momentum and neutrino massKaon veto, charge balanceFit Mx with constraints
MX distribution fit: bul, bcl, background
Errors:Statistical L(ab-1) = 0.08 0.5 2.0 10 stat(%) = 7.0 2.8 1.4 0.6
Experim. Systematic ~5% (now) 2.5% (bcl bkgd)
Theoretical ~ 9% ((mb)=90MeV) 5% (bulabove cut)Mx cut, b quark Fermi motion from b s, Mx binsFurther improvements from lattice QCD, restricted phase space
Mx (GeV)
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 30
Towards Vtd/Vts
10% error due to long range effectsto be compared to 6% for md/ms
From experience gained with present data
6
60600
103.2)(B
102.1)(B,104.1)(B
Br
BrBr
Significant gain if one can reduce the background by factor 2
0.5 ab-1
0.5 ab-1
2 ab-1
2 ab-1
Extrapolation
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 32
Charmless decays: Direct CP violation?Time-integrated CP asymmetries:
No evidence for direct CPV yet
Theoretical expectations:
Tree + Penguin: ACP 10%
Pure Penguin: ACP 1%
Present sensitivity (most channels)
statACP 10% systACP 12%
Charge asym.
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 33
EW Penguins (BaBar): 85M BB pairs
60.110.240.180.20 10)(0.78)lKl(B
B
C.L. 90% @103.0
100.28)(1.68)llK(B6
60.680.58
*
B
Preliminary
Exclusive measurements:
Inclusive (bsl+l-)in progress
Remaining neutral Energy (GeV)
m(D
0 )R
ec-m
(D0 )
PDG (
m(D
0))
SignalBox
Sideband
Theory (SM): B(B+K+) 3.8 x 10-6
56M BB pairs, fully reco. SL tag
B(B+K+) 9.410-5 (90% CL)
2 events observed (2.2 bkgd expected)
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 34
Leptonic decays (BaBar)• Already published, to be updated (Run1+2)
– BF(B ) < 1.7 10-6 (90% CL); int.lumi. 19.4 fb-1
• ICHEP 2002 (Run1+2):– BF(B e+e-) < 3.3 10-7 , BF(B +-) < 2.0 10-7 ,– BF(B +e-) < 2.1 10-7 (90% CL)
• New analyses on B+ + (Run1+2), with:– Lepton tag or Fully reconstructed hadronic tag– Sensitivity competitive with existing exptal limits (LEP: 5.7
10-4)
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 35
Some extrapolated yields (BaBar)• Extrapolated yields for B+ + and B+K+
Channel
sig tagTheor.pred.
Yield(0.1ab-1)
Yield(0.5ab-1)
Yield(2ab-1)
B+ + 0.20.2
1 10-
3
5 10-
3
5 10-5 16
636
24144
B+K+ 0.30.2
1 10-
3
5 10-
3
4 10-6 0.10.4
0.72
39Present analysis: backgrounds:
280 events in 80fb-1K 2 events in 56MBB pairs
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 36
Rare decays - SummaryProjections from Snowmass 2001: reconstructed events
Efficiencies from BaBar/Belle; some numbers should be updated(*) “B exclusive tag” (assuming 0.2%)
Decay mode
BF
Nrec 0.5 ab-1
Nrec 3.0 ab-1
Nrec 10 ab-1
B Xs (3.3 0.3) 10-4 1.7K (*) 10K (*) 34K (*)
B0 K*0 B0
(4.23 0.40 0.22) 10-5 10-6
6K 150
36K 900
120K 3K
B Xs
B Xse
e
B K*
B K*ee
6 10-6
2 10-6
300 (*) 350 (*) 120 150
1.8K (*) 2.1K (*) 720 900
6K (*) 7K (*) 2.4K 3K
B Xs
B K* 4 10-5 5 10-6
8 (*) 1.5 (*)
50 (*) 10 (*)
160 (*) 30 (*)
B
B
B B
10-7 10-9 5 10-5 1.6 10-7
17 (*) 8
100 (*) 50
350 (*) 150
B 10-8 0.4 2.4 8
Asymmetries!
Rates…
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 37
Conclusions & Outlook • B factories discovered CP violation in B decays and
are measuring sin2 with increasing accuracy
• Each of the two B factories integrated a luminosity of about 0.1ab-1 and should integrate 0.5ab-1 by 2006; depending on the machine upgrade options, about 2ab-1 per experiment could be within reach by the end of the decade
• Such an increase in integrated luminosity will significantly extend the physics reach of the B factories, both for the Unitarity Triangle, and for rare B decays
• Other topics, including charm and tau physics, are part of the physics program (see backup slides)
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 39
An example: D mixingVery small in the S.M. 2 additional suppression
A window for new physics
Sensitivity estimate (BaBar)1, including statistical and
systematic uncertainties
Charm
limit3
005.0 222
SU
mmm Wds
c
c
u
ud,s d,s
W-
W+
Vcd,cs
V*cd,csV*
ud,us
Vud,us
D0 D0
“long distance” -iy
“short distance” x
D0 D0K-,
K+,+
0.5 ab-1 5.0 ab-1
y 0.003 0.001
(x2+y2)/2
0.0002 0.0001
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 40
Another example: lepton number violation
S.M., extended to include mixing and mass:
BR( O(10 - 34)
BaBar sensitivity, projections:
tau
lepton number is violated inmany extensions of the S.M.(present limits, O(10-6) are closeto some model predictions)
Channel 4 sensitivity 0.1 ab-1
4 sensitivity 1.0 ab-1
4 sensitivity 5 ab-1
(e) 10-6 3 10-7 1.4 10-7
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 41
Expt. Collider Beams Sqrt(s) (GeV)
Year Online
Lumi(1033
cm-2 s-1) (b-bbar) (nb)
bb pairs (107/yr)
c (m)
(b-bbar)/ (q-qbar)
CLEOIII CESR CESR-IV
e+e- 10 10
1999 ?
1.2 30
1 1
1.2 30
30 30
310-1
310-1 BaBar Belle
PEP-II KEK-B
e+e-
asymm 10 10
1999 1999
3-10 3-10
1 1
3-10 3-10
270 200
310-1
310-1 HERA-B HERA pN 40 1999 - 6-12 50-100 9000 110-6 CDF-II D0 BTeV
Tevatron ppbar 1800 2000 2004
0.2-1.0 0.2
100000 20000 500 5000
110-3
LHC-B Atlas CMS
LHC pp 14000 2007 0.15 500000 75000 7000 500
510-3
B physics: acceleratorsHadron colliders:
Higher cross sctions, but: higher bkgd, lower efficiency
B-factories: Luminosity is the critical factor
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 42
DIRC PID)144 quartz bars
11000 PMs
1.5T solenoid
EMC6580 CsI(Tl) crystals
Drift Chamber40 stereo layers
Instrumented Flux Returniron / RPCs (muon / neutral hadrons)
Silicon Vertex Tracker5 layers, double sided strips
e+ (3.1GeV)
e- (9GeV)
BaBar Detector
SVT: B vertex z resolution ~70 micronsTracking: (pT)/pT = 0.13% pT 0.45%
DIRC: K- separation > 3.4 for P < 3.5GeV/c
EMC: E/E = 1.33%E-1/4 2.1%
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 43
• Error on the diluted CP asymmetries (Aobs = DACP)
– Number of events:
– Efficiencies:
– Dilutions:
• B factories– Small cross section:– higher efficiencies and better dilutions D2
CP asymmetries: sensitivity
02 fLdtN bbprod
tagCPdec
bkgdtagmix dddD
.).(501 collhadrbnbbb
prodobs
CPNBRDND
A
11
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 44
BaBar, sin2: “golden” modes, now
on-peak: 81.9 fb-1
off-peak: 9.6 fb-1
89 M BB pairs
J/ Ks (Ks +-)
J/ Ks (Ks 00)
J/ K*0 (K*0 Ks0)
c1 Ks
(2s) Ks
J/ KL
Bflav
Mixing sample
Flavor states: to measure mixing and D,
R
CP states with charmonium: to measure sin2
cp
2641 tagged events
25375 events
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 45
CP violation: sin2
cp
sin2 = 0.741 0.067 (stat) 0.034 (syst)sin2 = 0.741 0.067 (stat) 0.034 (syst)
cp
sin2 = 0.755 0.074 sin2 = 0.723 0.158
PRL 89 (2002) 201802
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 46
sin2 - K0S hep-ex/0207070
..%901056.0
109.05.1
7.17.8
108.00.12.9
pairs B1060
6
600
6*
6
LCBBF
KBBF
KBBF
S
Pure QCD Penguin, sensitive to New Physics contributions
In the SM, time-dependent asymmetry in K0
S measures sin2
B K0S
51 events
0.520.50sin 2 0.19 ( ) 0.09( )
stat systFrom 87 M B pairs:
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 47
sin2 - J/0 hep-ex/0207058
events
0 5( / ) (2.0 0.6 0.2) 10BR B J
0
0
/
/
0.05 0.49( ) 0.16( )
0.38 0.41( ) 0.09( )
J
J
S stat syst
C stat syst
0
0
/
/
0.05 0.49( ) 0.16( )
0.38 0.41( ) 0.09( )
J
J
S stat syst
C stat syst
++ If no penguins: we measure -sin2
3cdcbVV 3
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 48
sin2 - ’K0S
Large Penguin contribution expected !
B ’K0S
203 events
03.022.010.0
03.034.002.0
011.0045.0037.0
100.42.54.55'
104.45.39.76'600
6
C
S
A
KBBF
KBBF
CH
preliminary
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 49
sin2 - D*D* (b ccd)
B0D*+ D* •D*+D*-, is not a CP eigenstate (L=0,2 and L=1)
•CP odd fraction R R
•..Transversity analysis
2
2 2 20 ||
| |
| | | | | |
AR
A A A
2 21 d 3 3(1 )sin cos
d cos 4 2tr trtr
R R
CPCP-odd fraction-odd fractionRR = 0.07 = 0.07 0.06 0.06
0.030.03
CPCP-odd fraction-odd fractionRR = 0.07 = 0.07 0.06 0.06
0.030.03 mostly CP-even !
hep-ex/0207072
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 50
sin2 - D*D*
-sin-sin22 Small ( < 0.1 T) penguin contribution expected
++We measure :
•Im()
•||
From 126 12 signal events
Im(+) = 0.31 0.43 (stat) 0.13 (syst)
-sin2 = -0.741
0.067
|| = 0.98 0.25 (stat) 0.09 (syst)
preliminary
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 51
BaBar, sin2: modes with Penguins, now
K0S
51 events
J/0 events
’K0S
203 events
D*D*++
126 12 events
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 52
BaBar, present sin2eff : S and C
0.02 0.34( ) 0.05( )
0.30 0.25( ) 0.04( )
S stat syst
C stat syst
0.02 0.34( ) 0.05( )
0.30 0.25( ) 0.04( )
S stat syst
C stat syst
B→
2 1 /
1 /
2effsin(
sin(
)1 2
)
i i
i i
P T e e
P T e e
ie
C
C
S
PRL sub., hep-ex/0207055
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 53
Isospin analysis: projections - 2• Sensitivity to : toy MC with BaBar detector
• Assumptions (example):
L = 0.5 ab-1 L = 2.0 ab-1
<BR(B)> = 1.0x10-6
BR(B) = 4.1x10-6
BR(B0) = BR(B0) = 4.7x10-6
4-fold ambiguity !
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 54
The theoretical errorof 10% should be further
reduced at the 5%level using all information
P*l, Q2 and Mx
February 4, 2003 L.Lanceri - B-Factories: Physics Reach - CSNI 55
Exclusive b d, from 78fb-
1:(interesting for |Vtd/Vts|2)
Rare decays: EM Penguins
40.430.23
S
10(theory))0.37(sys)
0.36(stat)(3.88)XBF(
B
047.0*BFBF
102.1BF
103.2BF
..%90104.1BF
60
6
600
KBB
B
B
LCB
SM expectation:
60 101BF B
Present analysis limited byphotons from Continuum bkgd:without improvements:3 sensitivity at 0.8 (0.25) ab-1
if bkgd x 0.5, then: 3 sensitivity at 0.4 (0.1) ab-1
for individual (combined) modes
BF(B )/BF(B K*)
|Vtd/Vts|2
Fully inclusive b s, lepton tag