B P hysics at CDF R esults and P rospects
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Transcript of B P hysics at CDF R esults and P rospects
B Physics at CDFResults and Prospects
Iván Vila Instituto de Física de Cantabria, Spain
Lake Louise Winter InstituteLake Louise, Canada - 15th -22nd February 2003
Feb 18th 2004 I. Vila Lake Louise Winter Institute 2004 2
In this talk Introduction Cross-section Masses Lifetimes Spectroscopy Rare Decays CP Violation Bs Mixing
DISCLAIMER: 1001 B and Charm physics analysis at CDF
Here not at all exhaustive summary
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B physics at Tevatron Large b production cross-section
(bb) ~ 50b (5kHz @ E32) (bX, |y(b)|≤1) ~ 30b (3000Hz @ E32) compare: (bb) ~ 1nb at (4S) ( 10Hz @ E34)
Many B hadrons states produced: B0, B+, Bs, b, Bc, b
But… HUGE inelastic cross section ~ 100mb A dedicated selective trigger needed vs.
B factories inclusive trigger.
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B Triggers Di-lepton - dilepton sample
pT(/e)>1.5/4.0 GeV/c J/ modes, masses, lifetime, x-section Yield 2x Run I (low Pt threshold, increased acceptance)
lepton + displaced track - semileptonic sample pT(e/)>4 GeV/c 120 m<d0(Trk)<1mm, pT(Trk)>2 GeV/c Semileptonic decays, Lifetimes, flavor tagging. B Yields 3x Run I
Two displaced vertex tracks - hadronic sample pT(Trk)>2 GeV/c, 120 m<d0(Trk)<1mm, S pT>5.5 GeV/c Branching ratios, Bs mixing, …
primary vertexsecondary vertex
impact parameter
~ 1 mmb, c decays
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B production – Cross Section
RunI b cross-section ~ 3x NLO QCD theoretical approaches: new
physics, Next-to-Leading-log resummations, non perturbative fragmentation function from LEP, new factorization schemes…
Only top 10% in Pt of the total x-section measured
New measurements to lower pT(B) : Inclusive J/Psi cross section up to
PT(J/Psi)=0 (first time hadron collider)
Bottom Quark Production cross-section
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B Lifetimes and Masses Test of HQET predictions
Inclusive measurements (J/ X dimuon sample) Still statistical limited ~ 138 pb-1
First measurement of b using a exclusive reconstruc.
Lifetime measurements using the inclusive semileptonic sample are still under progress (expect results soon)
Mass fit using fully reconstructed B J/ X decays
B0, B+ competitive with PDG, and Bs and b the World’s best measurement
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Spectroscopy – Exotic States X(3872) New narrow state observed first by Belle in decay modes
Charmonium state not expected near mass peak.
D* Dbar deuteron-like molecule ?
CDF confirms X in 220pb-1 Preference for M( ) > 500MeV 670±90 candidates, sign.~ 12 Mass scale using (2S) peak
/J
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Rare decays - Bs,Bd BR(Bs ) ~ 10-9 in SM (SUSY physics two orders of
magnitude enhancement) Blind analysis optimized for 300-400 pb-1 (~ 1 0.3
expected bkg)
Limits at 90% C.L.BR(Bs->MuMu) < 5.8 E-7BR(Bd->MuMu) < 1.5 E-7
Bs factor 3 better than best published limit (Run I) Bd slightly better than Belle’s at LP03: 1.6 E-7@90%CL Still room for improvement: Acceptance & bkgs
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CPV - Two body charmless decays B h+h-
1. extracting the signal
Time dependent asymmetry Bd ( angle) and Bs KK ( angle) Direct CP asymmetry of the self tagging modes Bd K and Bs K
Online hadronic selection + B pointing prim. vertex, displaced & isolated
2. Separation of the components dE/dx ~ 1.3 for K/ separation Statistical separation is still possible Unbinned log-likelihood fit defined including
Kinematical variables M() and =(1-p1/p2)q1 dE/dx
Mode Yield (65 pb-1)
B0 K 14817(stat.) 17(syst)
B0 3914(stat.) 17(syst)
Bs KK 9017(stat.) 17(syst)
Bs K 311(stat.) 17(syst)
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CPV - Direct ACP Selftagging Modes - Projections First observation Bs
KK Direct ACP violation ~ 0
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Bs mixing – Signal Reconstruction Bs mixing unique to CDF requires
Event yield Clean signals (S/B) Vertexing resolution Tagging effectiveness: D2
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Fully reconstructed decays boost resolution
%5.0)()(
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CDF Golden Channel Bs Ds fst 67
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Bs Mixing - Flavor tagging Flavor taggers optimized on
high statistics semileptonic sample
Unbiased performance in high purity inclusive sample
CDF Results:Same-side (B+) D2(2.10.7)%Muon tagging D2 (0.70.1)%JQT, SET almost thereOSKT NEW! RunII on progress
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Bs Mixing – Improvements Idealistic “Yellow Book” projections
Detector acceptance and trigger efficiency very improved 2x Bs selection
Under current conditions (BsDs ) S = 1600 events/fb-1 S/B = 2/1 D2 = 4 % (SLT+SST+JQT) t=67 fs
Modest improvements Adding Ds K*K,KsK y Bs Ds3
S = 1600 events/fb-1 2000 events/fb-1
L00 innermost silicon layer, event by event beam-line reconstruction
D2 = 5 %
t=67 fs t=50 fs
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Bs Mixing – Projections Short term 500 pb-1 (no improvement up to 2005)
2(for ms = 15 ps-1) Reach the current indirect limit. Cover the Standard Model favored range
Beyond the SM favored range (conservative improvements up to 2008): 5 if ms = 18 ps-1 with 1.8 fb-1 5 if m = 24 ps-1 with 3.2 fb-1
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Summary and Conclusions After 2003 fall shutdown the Tevatron is performing very well. CDF Run II accumulated over 290pb-1 of data (~ 2.5 larger than
Run I). The new displaced track trigger has been a great success CDF is back in the game of producing world class results.
(Unique Bs,b physics, competitive Bd, Bu physics in same cases) Benchmark lifetime and mass analysis probe excellent detector
performance World best limits Bs and Bd First observation of Bs KK modes CPV in B hh, CDF major player in this arena. Bs mixing:
Reach current indirect limit with 500pb-1 (end 2004) 5sensitivity over SM preferred range (up to 24 ps-1) in 3fb-1(end
2008)