B-Factories: Physics Reach Luminosity
CPV and CKM
Rare B decays
ConclusionsLivio Lanceri – Univ. and INFN Trieste
INFN-CSNI – LNF, February 4, 2003
B-Factories: Physics Reach Luminosity
CPV and CKM
Rare B decays
Conclusions
Livio Lanceri – Univ. and INFN Trieste
INFN-CSNI – LNF, February 4, 2003
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
Experimental ingredients
z(CP) z(tag) Inclusive tag (lepton, K, …): tag(1-2w)2 28% rec 1540% (Exclusive tag: tag 0.10.2%) < z > 260 m
z (RMS) 190 m 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 level
High efficiencies, small bkgd
Unique tool at B factories: exclusive B tagging with fully rec. B (“single B beam”)
Luminosity is a key factor
B-Factories: experiments and luminosity
c.f. integrated luminosity for
Argus (1983-1987): ~100 pb-1
CLEO (1981-2000): ~16 fb-1 BABAR/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
NO (Super-KEKB?) SuperPEP/SuperBaBar
Year 20...?
New collider,
(and new detector…)
Snowmass: 370M$ Minimal upgrade
Feasible from 2005
Shut-down 3 months
0.40.5 ab-1/year
Limited cost 2ab-1
in 2009 From J.Seeman/SLAC
Path to higher PEP-II luminosity
Luminosity 4.6E33 1E34 2E34 4E34 Units
I+ 1800 2700 3600 4500 mA
I- 950 1400 1760 2000 mA
Beta y* 11.5 9 7 4.5 mm
Beta x* 50 50 50 50 cm
Bunch Length 1.3 1.0 0.8 0.5 cm
# bunches 792 1300 1500 1600
Vert. Emitt. 2.5 1.4 1.1 0.7 nm
Horiz. Emittance 40/50 30/45 32/47 40/48 nm (+/-)
Crossing angle 0 0 0 ~+/-8 mrad
Tune shifts (x/y) 7.5/4.5 8.0/5.7 8.2/6.0 8.4/6.3 x100
Number RF stations 7 10 13 15
Date hardware ready Jan 02 Dec 02 Dec 04 Nov 05
Date for luminosity Jun 02 July 03 Dec 05 Dec 06
(J.Seeman, BaBar Collaboration meeting, Sept.2002)
BaBar Long Term Planning TF
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
What about KEK-B/Belle upgrades ?
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
CPV and CKM: phases sin2
sin2
CPV in mixing-decay interference direct CPV
dN exp(–|Dt|/tB) ( 1 ± D (S sin(DmDt) - C cos(DmDt)) ) R
CP asymmetry: Time Dependence Amplitude ratio B0fcp/B0fcp CP eigenvalue B mixing Measured from data (Flavour sample)! D mis-tag dilution
R time resolution Flavour tag
BaBar, sin2b: results
sin2b = 0.741 0.067 0.034 sin2b = 0.755 0.074 sin2b = 0.723 0.158 Charmonium modes Modes with Penguins Yield in Standard Model on-peak: 81.9 fb-1
off-peak: 9.6 fb-1
89 M BB pairs tagged CP sample: 2631
flavor sample: 25375 (pure Penguin!)
BaBar, sin2b: systematics
0.034 Total 0.003 Dmd 0.004 B lifetime 0.010 Fit bias correction 0.012 Signal Dilutions 0.017 Dt meas. and RF 0.015 Klong BG 0.017
0.008 CP and Mix BG
DCS decays, tag side dsin2b Source 0.004
0.008
0.003
0.010
0.010
0.003
0.003
0.003
0.018 Asymptotic Using only
lepton tags:
0.01 decays with charmonium:
sin2b: projected errors (BaBar)
Extrapolated statistical and systematic uncertainties
Statistical uncertainty
For “golden” modes only
sin2eff from B0+- b d d u d u p+ p- B0 Mixing + T: b+g b d d d u u p- p+ t B0 P: -b,d Observables in +-
CP asymmetry (time-dependent) Extra weak phase –b, strong phase d, and |P/T|, modify a by k : from isospin analysis
BaBar and Belle: Spp and Cpp
With incomplete information
(no isospin analysis):
Measure Spp and Cpp from both sinDmDt and cosDmDt terms .
Compare with predicted Spp and Cpp values for given a, b, |P/T|, and d. Assume for instance: cf. Gronau and Rosner, Phys. Rev. D65, 093012 (2002) BABAR Belle 1 Belle 2
Results and extrapolations for sin2eff
Extrapolated errors (BaBar) Results (0.08 ab-1)
sin2: isospin analysis (Gronau & London)
BR (10-6) B0 → p+p0
B0 → p0p0
A Yield Mode Need flavor tagged rates for
+-, 0, 00 BaBar:
Upper bounds on = 2eff-2
Grossman-Quinn bound: BaBar, present data: BaBar, extrapolations: vs BF(00),
at fixed Luminosity Small gain
with lumi Most powerful
at small BF
Isospin analysis: projections - 1
L = 0.5 ab-1 L = 2.0 ab-1 BR(B`gp` p0) = 4.1x10-6
BR(B0gp+ p-) = BR(B0gp+ p-) = 4.7x10-6 NB: 4-fold ambiguity ! = 2.0x10-6 Sensitivity to : toy MC with BaBar detector
Assumptions (example):
Comments