Download presentation
Presentation is loading. Please wait.
1
B physics: new states, rare decays and branching ratios in CDF Vyacheslav Krutelyov Texas A&M University For CDF Collaboration July 1, 2004 BEACH04 Chicago, IL
2
7/1/04 S. Krutelyov B physics: new and rare BEACH04 2 Outlines CDF Run2 Detector Triggers Searches B s(d) D 0 Measurements (successful searches) X(3872) B + J/ B s and pentaquarks See talks by S.D’Auria and D.Litvintsev
3
7/1/04 S. Krutelyov B physics: new and rare BEACH04 3 Tevatron performance As you know the Tevatron is working very well this year Record initial luminosity = 84 10 30 cm -2 s -1 (92 10 30 cm -2 s -1 to CDF) Detector efficiency ~85-90% ~450pb -1 on tape 100-200+ pb -1 used for analysis so far
4
7/1/04 S. Krutelyov B physics: new and rare BEACH04 4 CDF Run2. s=1.96TeV σ(Inelastic)~60mb. ℒ ~7 10 31 cm -2 s -1 (~400pb -1 good recorded) Plan: ~8 10 31 cm -2 s -1 (Run2a); ~2 10 32 cm -2 s -1 (4-8/fb Run 2) 1.7MHz collision 20kHz L1 trigger 350Hz L2 60Hz L3/logging rate. ~80% L1 (~1/3 at L3) of the trigger (bandwidth) are B physics Better silicon coverage ( 2), muon detection, improved tracking. Better triggers: lower track p T, higher efficiency. Run2 vs Run1 SVX II (5layer) silicon strip det svx+IP ~40 m COT tracker drift chamber p T /p T 2 ~0.1% p T /p T 2 ~1.5%(L1/XFT) CMU muon det (drift cham) p T >1.5GeV | CMP muon det (drift cham + scint) p T >2.5GeV | 2 ft steel CMX muon det (drift cham + scint) p T >2GeV 0.6<|
5
7/1/04 S. Krutelyov B physics: new and rare BEACH04 5 Triggers used Dimuon trigger p T >1.5GeV, p T >2GeV, 0.6< 1 p T, , muon ID used to cut on tracks Used for X) Two Track Trigger p T >2GeV, p T, , d 0 info used to cut on 2 tracks Used for: B,D hadrons ; D All are input to the various Level-3 triggers That use the offline quality information primary vertex secondary vertex impact parameter ~ 1 mm b, c decays Semileptonic trigger p T, , d 0, muon ID used to cut on tracks Used for ,D, X) no results presented in this talk
6
7/1/04 S. Krutelyov B physics: new and rare BEACH04 6 Triggers used Dimuon trigger p T >1.5GeV, p T >2GeV, 0.6< 1 p T, , muon ID used to cut on tracks Used for X)
7
7/1/04 S. Krutelyov B physics: new and rare BEACH04 7 Triggers used Two Track Trigger p T >2GeV, p T, , d 0 info used to cut on 2 tracks @L2 Used for: B,D hadrons ; D primary vertex secondary vertex impact parameter ~ 1 mm b, c decays
8
7/1/04 S. Krutelyov B physics: new and rare BEACH04 8 B(D) : Theoretical motivations. Current limits. Flavor Changing Neutral Current. Loop contribution only in SM. Br SM (B s μ + μ - )=(3.4±0.5) 10 -9 Br SM (B d μ + μ - )=(1.00±0.14) 10 -10 (hep-ph/0303060) Br SM (D 0 μ + μ - )~3*10 -13 (GIM suppressed) Only upper experimental limit exists: Br exp (B s μ + μ - )<2.0 10 -6 90% C.L. CDF RunI @100/pb. Br exp (B d μ + μ - )<1.6 10 -7 90% C.L. Belle ‘03 @78/fb. Br exp (D 0 μ + μ - )<4.1(4.2)*10 -6 90% C.L. BEATRICE(E771) Limits are far away from the SM value: can test for a possible new physics. MSSM: Br( B μ + μ - ) enhanced by tanβ>10 terms ~tan 6 β. Up to 100 over the SM prediction. R-parity violating models give tree level contributions. Not heavily constrained by other observables. Can be seen in Run2 (esp. B s ) Other models enhance less. E.g., universal extra dimensions. Up to +70% for B s μ + μ - ’ i23 i22 b s RPV mSUGRA,SO(10)
9
7/1/04 S. Krutelyov B physics: new and rare BEACH04 9 D 0 search 1.012 1.43·10 -3 Use D *± D 0 π ± tagged events Use D 0 as a normalization mode. Blind from ID in 1.840<m <1.882 GeV Cuts: |d 0 (μ,π)|>120μm, |d xy (D 0 )|<150μm Δφ(μμ)>0.085 Background: combinatorial (from right sideband) – expect 1.5±0.7 misidentification (punch-through/decay) – expect N(D 0 ) P(misID) 2 0.3±0.1
10
7/1/04 S. Krutelyov B physics: new and rare BEACH04 10 D 0 search B(D 0 )<2.4 10 -6 @ 90% C.L. B(D 0 )<3.1 10 -6 @ 95% C.L. This result improves on the previous limits by ~ 2 (4.1 10 -6 from BEATRICE, and 4.2 10 -6 from E771 at 90% C.L.) 69pb -1
11
7/1/04 S. Krutelyov B physics: new and rare BEACH04 11 Br(B s(d) μ+μ-) measurement. Expect to detect at most few events that might only look like B s(d) μ+μ– SM predicts 0 events really a “search” Don’t look at the data signal region (blind search) Signal inside 5.169<M GeV/c 2 ( 3 window demonstrate understanding of background events accurately estimate (acceptance) and (efficiency) intelligently optimize cuts CL=90% upper limit on for n obs and n bg 171pb-1 or 10 trillion collisions only Run1 Bs =0.9 b for p T s >6 GeV/c, |y|<1 (use this as a baseline selection) 3% (CMU&CMP Run1) 25% Run1 Dimuon trigger and p T >6GeV baseline sample: 2940 events
12
7/1/04 S. Krutelyov B physics: new and rare BEACH04 12 Signal & Background Need to select discriminating variables that leave most of the signal and remove most of the background. P T PTPT x y B s R < 1 ( < 57 o ) PTPT P T vtx Most Promising Discriminating Variables – Invariant mass – c : 2D lifetime c – : (p T B ) – (vtx) – Isolation: Largest expected background: gluon splitting g bb
13
7/1/04 S. Krutelyov B physics: new and rare BEACH04 13 Optimization Results Optimize on (M , c , , Iso) to get the best expected limit (c , ,Iso) = (>200 mm, 0.65) and mass window 80 MeV around world avg Bs(d): 5.369 GeV (5.279 GeV) Bs(d): total = (2.0 0.2)% ( 6.6%, total 30%) Accepted bgd = (6 2) fb Expected bacground in 171pb -1 = 1.1 0.3 events Poisson prob
14
7/1/04 S. Krutelyov B physics: new and rare BEACH04 14 Observed limits BR(B s μ + μ ) < 5.8x10 7 90% C.L. (7.5x10 7 95% C.L.) 3 times better than Run I (previous world best) BR(B d μ + μ ) < 1.5x10 7 90% C.L. (1.9x10 7 95% C.L.) slightly better than (1.6x10 7 90% C.L., just published) B-factory/Belle result
15
7/1/04 S. Krutelyov B physics: new and rare BEACH04 15 for SUperSYmmetry (@95% C.L.) 7.5 10 -7 R. Arnowitt et al., PLB 538 (2002) 121, new plot by B.Dutta R-parity violating R. Dermisek et al., hep-ph/0304101 SO(10) significant New limit excludes significant amounts of the previously allowed SUSY models parameters (more to go) Dark matter allowed region new exclusions @95% CL
16
7/1/04 S. Krutelyov B physics: new and rare BEACH04 16 Spectroscopy – Exotic States X(3872) New narrow state observed first by Belle in decay modes J/ 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
17
7/1/04 S. Krutelyov B physics: new and rare BEACH04 17 X(3872): Long-lived fraction Long-lived fraction: F X(3872) =16.1 4.9 2.0 % cf F (2S) = 28.3 1.0 0.7 % CDF II
18
7/1/04 S. Krutelyov B physics: new and rare BEACH04 18 B J/ Cabibbo-suppressed decay B + J/ Br Expected to be 5% relative to Br(B + J/ K + ) Br(B + J/ + )/Br(B + J/ K + )=4.2 0.7% PDG02 Signal selection p T (B + )>6.5GeV, p T (K + )>2GeV, L xy >200 m
19
7/1/04 S. Krutelyov B physics: new and rare BEACH04 19 Summary Great physics results are coming in from CDF Br(B s )<5.8 x 10 -7 at 90% C.L. Br(B d )<1.5 x 10 -7 at 90% C.L. Br(D )<2.4 x 10 -6 at 90% C.L. X(3872) confirmation Long-lived fraction F X(3872) =16.1 4.9 2.0 % . accepted/published by PRL
20
7/1/04 S. Krutelyov B physics: new and rare BEACH04 20
21
7/1/04 S. Krutelyov B physics: new and rare BEACH04 21 BACKUP SLIDES
22
7/1/04 S. Krutelyov B physics: new and rare BEACH04 22 Data Samples —OS+ : opposite-sign muon pairs, ctau > 0 our signal sample – not used for xchecks — OS- : opposite-sign muon pairs, ctau < 0 — SS+ : same-sign muon pairs, ctau > 0 — SS- : same-sign muon pairs, ctau < 0
23
7/1/04 S. Krutelyov B physics: new and rare BEACH04 23 R. Arnowitt et al., hep-ph/0203069, PLB 538 (2002) 121 mHmH Overlap with measured δa μ (BNL) in mSUGRA parameter space. Overlap with dark matter=LSP allowed region. Eliminate large parameter space (~ all for tanβ>40), with Br(B s μ + μ - )~10 -8 in Run2 (15/fb) Motivations: B s μ + μ - (mSUGRA)
24
7/1/04 S. Krutelyov B physics: new and rare BEACH04 24 _ ’ i23 i22 b s c b l s l R. Arnowitt et al., hep-ph/0203069, PLB 538 (2002) 121 15 fb 1 2 fb 1 e.g., W TRPV = ijk L i L j E k ’ ijk L i Q j D k ’’ ijk U i D j D k R P Violation: Br vs. m 1/2
25
7/1/04 S. Krutelyov B physics: new and rare BEACH04 25 B hh PR plot now ~1K events with 180/pb
26
7/1/04 S. Krutelyov B physics: new and rare BEACH04 26 M [GeV/c 2 ] CDF, PRD 57, 3811 (1998) Ldt = 98 pb 1 (~5 x 10 12 collisions) B d : 5.205-5.355 GeV/c 2 B s : 5.300-5.450 GeV/c 2 N obs = 1 with 5.344 GeV/c 2 (consistent with an expectation from the Standard Model backgrounds) Br(B d ) < 8.6 x 10 7 (95% C.L.) Br(B s ) < 2.6 x 10 6 (95% C.L.) B d(s) : Run I Results
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.