3/13/2005Sergey Burdin Moriond QCD1 Sergey Burdin (Fermilab) XXXXth Moriond QCD 3/13/05 Bs Mixing, Lifetime Difference and Rare Decays at Tevatron

3/13/2005Sergey Burdin Moriond QCD2 Tevatron Detectors DØ Excellent Coverage Muon System: |η|<2 Tracking System: |η|<3 Good Muon Triggers High Yields for Events with Muons Large B samples CDF Excellent Tracking Good impact parameter and mass resolution Hadronic Triggers Particle ID by dE/dx and TOF

3/13/2005Sergey Burdin Moriond QCD3 1E+32 Collider Run II Peak Luminosity Tevatron and Detectors Performance Delivered ~800pb -1 Recorded ~600pb -1 per experiment 10x increase in statistics before 2009 High Data Taking Efficiency 90%

3/13/2005Sergey Burdin Moriond QCD4 - SM: 1) 2) In SM B-mixing is explained by box diagrams Constrains V td and V ts elements of CKM matrix New physics → new particles in the box Mixing frequency  m d has been measured with high precision at B factories (0.502  ps -1 )  m s /  m d is free from many theoretical uncertainties Oscillations in Bs system haven’t been observed yet B / B mixing Flavour of B d and B s mesons can change – phenomenon called mixing 1987 : ARGUS (DESY) – large mixing for B d First indication that top quark was very heavy

3/13/2005Sergey Burdin Moriond QCD5 B s Mixing DØ Complex measurement with many components Goal was to develop necessary tools and have a baseline result to build on in the future Use semileptonic data sample μD s One decay mode D s  Φπ, Φ  K + K - 13,300 candidates in 460pb -1 Charge of the muon provides Final State Tag Initial State Tagging using the Opposite-Side B hadron Always require muon Improve tagging using additional information (P T, P T rel, Secondary Vertices) Combine tagging variables into probability discriminator Binned Asymmetry Asymmetry=(N nomix -N mix )/(N nomix +N mix ) Visible Proper Decay Length Use first 0.06cm of VPDL where resolution is not strongly affected by neutrino

3/13/2005Sergey Burdin Moriond QCD6 μD s sample and DØ 376±31 tagged μD s candidates in VPDL range [-0.01 ÷ 0.06] cm Understanding of resolution is crucial for Δm s measurement Measured and tuned tracking errors in data and MC Track momentum and angles Silicon detector hit configuration and cluster width one configuration is shown below Data before tuning Data after tuning Track IP errors IP resolution ln(σ 2 IP ) -ln(p 2 sin 3 θ) DØ Run II Preliminary D±sD±s D±D± ln(σ 2 IP )

3/13/2005Sergey Burdin Moriond QCD7 Assume that Mistag Rate is the same for Bu, Bd and Bs mesons Use asymmetries in μD 0 (dominated by Bu) and μD *± (dominated by Bd) samples to determine and cross- check the Mistag Rate Mistag Rate for B u Wrong Tag Fraction = 26.6±1.5% Dilution = 46.8±3.0% Mistag Rate for B d Wrong Tag Fraction = 27.6±2.1% Dilution = 44.8±4.2% Sample composition B s  D s (*) μ νX  Signal contamination c  μX, c  DsX Suppressed by requirement of muon from other side B s  D s (*) D s (*) X B u,d  DD s X μD0μD0 Asymmetry Fit Input DØ μD *±

3/13/2005Sergey Burdin Moriond QCD8 B s Mixing Result from DØ Asymmetry in μD s ± sample shows no evident oscillations Use Amplitude method to set limit 95% CL limit: Δm s <5.0ps -1 Sensitivity: 4.6ps -1 Contributions to systematic error from uncertainties in Mistag Rate Sample Composition Resolution Lifetime Efficiency Mass Fitting Procedure Momentum Non-zero ΔΓ s μD±sμD±s

3/13/2005Sergey Burdin Moriond QCD9 ΔΓ s /Γ s Angular Analysis B s  J/ψ Φ is mixture of CP =+1 & CP = -1 states Three-angle distribution for B s decay are muon and kaon angles in J/ψ and Φ rest frames Integration over leads to one-angle distribution In Standard Model: ΔΓ S /Γ S =0.12±0.06 ΔΓ S /Δm S = x10 -3

3/13/2005Sergey Burdin Moriond QCD10 Result on ΔΓ s /Γ s from CDF Three-angle analysis 203±15 B s →J/ψ Φ candidates Unconstrained Fit τ L = ±0.02ps τ H = ±0.03ps ΔΓ s = ±0.01ps -1 ΔΓ s /Γ s = ±0.01 Constrained Fit: = Γ d τ L = ±0.02ps τ H = ±0.03ps ΔΓ s =0.46±0.18±0.01ps -1 ΔΓ s /Γ s = ±0.01

3/13/2005Sergey Burdin Moriond QCD11 Result on ΔΓ s /Γ s from DØ B s  J/  (        (      From 483±32 B s  J/  (        (      candidates With constraint from the world average c  s from B s semileptonic decays Allowing for a free CP violating angle ΔΓ s /Γ s =(ΔΓ s /Γ s  SM cos 2 (  ) using SM constraint (ΔΓ s /Γ s  SM =0.12 ± 0.06: DØ Run II Preliminary

3/13/2005Sergey Burdin Moriond QCD12 B s →μD s1 DØ D s spectroscopy expects two narrow states with orbital momentum L=1 above D * K threshold: D s1 and D s2 D s1  D * K s (~50%) Use large μD *± sample (53k candidates in 483pb -1 ) Combine with K S See 18.5±5.5 B s  XμD s1 (→D *± K S ) candidates First observation of this B s decay mode BaBar

3/13/2005Sergey Burdin Moriond QCD13 B s CDF b  sss decays in B s mesons Standard model BR(B s   ) =( )x10 -5 First observation of B s   12 events in signal region with 2 background events expected Normalized to B d  J/ψ K 0* BR(B s  ) = (1.4±0.6 stat. ±0.2 syst. ± 0.5 BR )x10 -5

3/13/2005Sergey Burdin Moriond QCD14 Search for B s DØ Rare decay induced by electroweak penguin and box diagrams Use B s →J/ψ Φ for normalization (74±11 ev.) Expected =1.2·10 -5 Limit is BR(B s →μμΦ) < 6.7·10 -5 (CDF Run I ) B s →J/ψ Φ

3/13/2005Sergey Burdin Moriond QCD15 Search for B s CDF & DØ Standard Model BR ~ 4x10 -9 BR could be 100x larger in some SUSY models Tevatron results CDF: BR(B s →μμ)<7.5x10 -7 (95%CL) [PRL (2004)] (171pb -1 ) DØ: BR(B s →μμ)<5.0x10 -7 (95%CL) [PRL (2005)] (240pb -1 ) DØ Update BR(B s →μμ)<3.7x10 -7 (95%CL) (300pb -1 )

3/13/2005Sergey Burdin Moriond QCD16 FCNC Charm Decays Large cross section for beauty AND charm BR(D 0  μμ)≤2.4x10 (CDF Run II, 69pb -1 ) Search for D→  DØ, 530pb -1 First search for resonances:  →  >7σ observation of D s D + < 3.1 x 10  →   → 

3/13/2005Sergey Burdin Moriond QCD17 Summary Large B work CDF & DØ presented for the first time key measurements of the B physics program at Tevatron: B s mixing ΔΓ s Exploring unknown territory in rare beauty and charm decays More data is coming Double statistics every year next few years 10x increase statistics by 2009 Stay tuned!