b physics outlook at tara shears. outline b physics at cdf –production –triggering b physics...
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B physics outlook at
Tara Shears
Outline
• B physics at CDF– production– triggering
• B physics outlook (+ some current results)– Mixing– CP violation– Rare decays / new physics
• Summary
B production at CDF
Similar production cross-sections to LHC
bb production cross-section high
So is charm
So is inelastic …
All B species produced in same ratio as LHC
Bs sector can be explored before LHCb
√s (TeV)0.001 0.01 0.1 1.0 10 102
1mb
1b
1nb
1pb
SppSTevatron
LHC(pp→X)(-)
(bb)
Heavy flavour triggers
Dilepton
2 leptons: several Pt thresholds
Lepton + displaced track
Pt (lepton)>4
Pt(trk)>2 + 120m<d0<1mm
2 displaced tracks
Pt(trk)>2 GeV, Pt >5.5 GeV
120m<d0<1mm SVTBd0
Displaced track trigger (SVT)
Level 2 displaced track trigger
(d0) ~ 47 m– 15 s operation
• online primary vertex finding, tracking
• trigger on displaced tracks (large d0)
• n.b. cross-sections grow with luminosity….
Data taking outlook
4.4 – 8.5 fb-1 forecast by end 2009
2.5 – 5 fb-1 by mid-2007
600 pb-1 on tape now
Typically 350pb-1 analysed
Physics
• Focus on projected CDF B physics highlights – B0
s mixing, CP violation, rare decays– Taken from “yellow book” hep-ph/0201071
• Show current achievements
• Translate this into future expectation where possible
B0s mixing goals
Needed prior to CP violation measurements
Within 2fb-1 CDF should cover SM allowed range
Sensitivity originally estimated as function of
D2 (originally 11.3%)
Lifetime resolution t(45 fs)
Yield (25000 – 75000)
S:B (1:2 – 2:1) xs of 70 ≡ ms of 45
SM ms < 24.6 ps-1
Mixing status now
360 pb-1:
900 Bs Ds:
D2 = 1.1 ± 0.2%
t = 100 fs
7700 BsDsl:
D2 = 1.4 ± 0.1%
t larger (missing )
Mixing outlook
Mixing reliant on efficiency, dilution, time resolution
Work ongoing to improve tagging, yields, decay time resolution
Baseline:
D2 = 1.6%
t = 67 fs
Stretch:
D2 = 2.6%
t = 47 fs
(Compared to 250 pb-1)
SM
4.5 fb-1
CP violation goals
Via ACP of:
B0 , K
B0 D0K*
B0s DsK
B0 J/ K0s
B0 K0s
B0 J/ for New Physics (ACP small in SM)
B0s mixing
VtdVtb*
R. Fleischer, Phys. Lett. B459 306 (1999)
CP violation now180pb-1 analysed:
ACP(B+ K-) = -0.04 ± 0.08 ± 0.01
ACP (BK0s) = -0.07 ±0.17 +0.03-0.02
(47 events) hep-ex/0502044
Triggered by SVT:
ID via dE/dx or ToF information
CP violation outlook
Yellow book predictions for 2fb-1:
sin2 measured to ±0.13 ±0.076
Assumes D2 = 3 7.8%
measured to 0.1
Error on ACP in B as fn. lumi
Much work underway to improve tagging and event yields before these targets can be met.
(Time dependent ACP ACP
DIR,ACPMix)
Rare decay goals
Aims of run 2:– Observe B X– Observe radiative decays
• Eg. B K*0 (SM BR ~10-7)
– Stringent limits on B (SM br ~ 10-10)
– Deviations from SM could signal New Physics
Rare decays now
PRL 93, 032001 2004
Bd/Bs 171 pb-1
BR(Bs ) < 5.8*10-7
@90%CL
Work ongoing in other modes
Rare decay outlook
In 2fb-1:
B limit outlook
Expected observation of :
B K*0
Yellow book predicts ~60 events (for BR B K*0 =1.5 x10-6)
B X
Yellow book predicts 100-300 B+ K, 400-1100 B0 K0
Summary
CDF projected results by 2009:B0
s mixing measured (for all SM values of ms)
Measurements of and in unitarity triangle to ±0.1
Observation of rare decay modes and indirect test of New Physics production
Note: all forecasts dependent on reaching predicted performance, receiving planned luminosity …
Backup slides
COTNucl. Instrum. Meth. A526: 249, 2004
96 layers, radii 0.3-1.4m
4 axial superlayers (12 wires)
4 stereo superlayers (±35 mrad)
200m hit resolution
Dpt/pt = (0.7 0.1pt)%
dE/dx for e//K/p
1.2 /K if pt>2 GeV
750 000 channels!
Impact parameter resolution 13 + 40/pt m
Layer00: 2cm radius, single sided
SVX: 2.5-10cm radius, 5 layers, double sided
ISL: 20-30cm radius, 1-2 layers, double sided
Silicon
Trigger system
(thanks to Rolf Oldeman)
mttBBNtBBN
tBBNtBBNtA
ssss
ssss
cos
))(())((
))(())(()(
0000
0000
In practice: use amplitude scan method• introduce amplitude to mixing probability formula
• evaluate at each m point• Amplitude=1 if evaluated at correct m • Allows us to set confidence limit when 1.645
H. G. Moser, A. Roussarie, NIM A384 (1997)
Bs mixing
Mixing systematics
Bs yields