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Published byBenjamin Keene Modified over 10 years ago
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B physics outlook at Tara Shears
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Outline B physics at CDF –production –triggering B physics outlook (+ some current results) –Mixing –CP violation –Rare decays / new physics Summary
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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 B s sector can be explored before LHCb s (TeV) 0.001 0.01 0.1 1.0 10 10 2 1mb 1 b 1nb 1pb SppS Tevatron LHC (ppX) (-) (bb)
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Heavy flavour triggers Dilepton 2 leptons: several Pt thresholds Lepton + displaced track Pt (lepton)>4 Pt(trk)>2 + 120 m<d 0 <1mm 2 displaced tracks Pt(trk)>2 GeV, Pt >5.5 GeV 120 m<d 0 <1mm SVT B d0d0
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Displaced track trigger (SVT) Level 2 displaced track trigger – (d 0 ) ~ 47 m –15 s operation online primary vertex finding, tracking trigger on displaced tracks (large d 0 ) n.b. cross-sections grow with luminosity….
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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
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Physics Focus on projected CDF B physics highlights – B 0 s mixing, CP violation, rare decays –Taken from yellow book hep-ph/0201071 Show current achievements Translate this into future expectation where possible
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B 0 s mixing goals Needed prior to CP violation measurements Within 2fb -1 CDF should cover SM allowed range Sensitivity originally estimated as function of D 2 (originally 11.3%) Lifetime resolution t(45 fs) Yield (25000 – 75000) S:B (1:2 – 2:1) x s of 70 m s of 45 SM m s < 24.6 ps -1
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Mixing status now 360 pb -1 : 900 B s D s : D 2 = 1.1 ± 0.2% t = 100 fs 7700 B s D s l : D 2 = 1.4 ± 0.1% t larger (missing )
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Mixing outlook Mixing reliant on efficiency, dilution, time resolution Work ongoing to improve tagging, yields, decay time resolution Baseline: D 2 = 1.6% t = 67 fs Stretch: D 2 = 2.6% t = 47 fs (Compared to 250 pb -1 ) SM 4.5 fb -1
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CP violation goals Via A CP of: B 0, K B 0 D 0 K* B 0 s D s K B 0 J/ K 0 s B 0 K 0 s B 0 J/ for New Physics (A CP small in SM) B 0 s mixing V td V tb * R. Fleischer, Phys. Lett. B459 306 (1999)
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CP violation now 180pb -1 analysed: A CP (B + K - ) = -0.04 ± 0.08 ± 0.01 A CP (B K 0 s ) = -0.07 ±0.17 +0.03-0.02 (47 events) hep-ex/0502044 Triggered by SVT: ID via dE/dx or ToF information
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CP violation outlook Yellow book predictions for 2fb -1 : sin2 measured to ±0.13 ±0.076 Assumes D 2 = 3 7.8% measured to 0.1 Error on A CP in B as fn. lumi Much work underway to improve tagging and event yields before these targets can be met. (Time dependent A CP A CP DIR,A CP Mix )
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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
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Rare decays now PRL 93, 032001 2004 B d /B s 171 pb -1 BR(B s ) < 5.8*10 -7 @90%CL Work ongoing in other modes
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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 B 0 K 0
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Summary CDF projected results by 2009: B 0 s mixing measured (for all SM values of m s ) 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 …
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Backup slides
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COT Nucl. Instrum. Meth. A526: 249, 2004 96 layers, radii 0.3-1.4m 4 axial superlayers (12 wires) 4 stereo superlayers (±35 mrad) 200 m hit resolution Dpt/pt = (0.7 0.1pt)% dE/dx for e/ /K/p 1.2 /K if pt>2 GeV
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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
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Trigger system
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(thanks to Rolf Oldeman)
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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) B s mixing
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Mixing systematics
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B s yields
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