B Physics Results from the Tevatron S. Burdin on behalf of CDF and DØ collaborations Aspen Particle Physics Conference 17-23 Jan 2010 Aspen, Colorado.
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B Physics Results from the Tevatron S. Burdin on behalf of CDF and DØ collaborations Aspen Particle Physics Conference 17-23 Jan 2010 Aspen, Colorado Outline • B physics at the Tevatron • CP violation in BS system – S (φS) measurements – ASL measurements • FCNC decays – B0K*μμ and Bsφμμ – Bsμμ – Bsφφ 19 Jan 2010 B Physics @ Tevatron / S.Burdin 2 B Physics at Tevatron • b production in pp collisions q b q b g b b b g Flavor Creation q b g Flavor Excitation q Gluon Splitting g • Fragmentation to all sorts of b-hadrons • Challenge: – Trigger – Reconstruction – Total inelastic cross section is ~1000 larger than b cross section 19 Jan 2010 B Physics @ Tevatron / S.Burdin 3 Triggering • Single-muon triggers (DØ) semileptonic • Dimuon triggers (CDF & DØ) Υ,J/ψX, μμX, semileptonic+tagging . • Displaced track triggers (CDF) 19 Jan 2010 o +lepton semileptonic o x2 fully hadronic B Physics @ Tevatron / S.Burdin 4 CP violation • CP violation (CPV) – violation of symmetry of physics laws in combined Charge-conjugate and Parity transformation P M.C.Escher rehcsE.C.M C CP M.C.Escher 19 Jan 2010 rehcsE.C.M B Physics @ Tevatron / S.Burdin 5 CP violation • CP violation (CPV) – violation of symmetry of physics laws in combined Charge-conjugate and Parity transformation P M.C.Escher rehcsE.C.M C CP M.C.Escher 19 Jan 2010 rehcsE.C.M B Physics @ Tevatron / S.Burdin 6 Bs0 Bs0 Mixing& CP parameters Flavor eigenstates propagate according to the Schrödinger Eq. d i dt | | Γ M i Bs (t) 2 = * 0 Γ * Bs (t) M i 12 12 2 0 1 Mass | BL = H eigenstates p2 q 2 M12 i Γ12 | Bs0 (t) 2 Γ | B 0 (t) M i s 2 p | B q | B 0 s 0 s If q/p=1 No CP violation Bs 0 Δms = MH ML 2 M12 ΔΓs = ΓL ΓH 2Γ12 cosφs Phase φ SM s New Physics effects: β SM s 19 Jan 2010 φs φsSM φsΔ Bs0 or M12 ~ 0.004 = arg Γ 12 2βs 2βsSM φsΔ VtsVtb* 2 4 arg ηλ O λ 0.02 * VcsVcb B Physics @ Tevatron / S.Burdin 7 BsJ/ψ + Ф analysis • J/ψ + Φ is an admixture of CP(even) and CP(odd) states • Angular analysis is used to separate the CP components and measure the lifetimes of each component and phase φs J/ψ rest frame • The angular distributions for CP-even and CP-odd states have distinctive differences 19 Jan 2010 φ rest frame B Physics @ Tevatron / S.Burdin 8 BsJ/ψ + Ф analysis Bs0 t 0 19 Jan 2010 B Physics @ Tevatron / S.Burdin Bs0 t 0 9 J/ψ+Φ data samples • Analyzed: 2.8fb-1 per experiment • Signal events: – DØ: ~2000 – CDF: ~3200 19 Jan 2010 B Physics @ Tevatron / S.Burdin 10 βs and ΔΓs Results DØ note 5928 CDF note 9787 Assuming the standard model predictions of βs and ΔΓs, the probability of a deviation as large as the level of the observed data is 3.4%, corresponding to 2.12 Gaussian standard deviations 19 Jan 2010 One of the possible explanations for large βS can be existence of the 4th generation (W.-S. Hou, et al., PRD 76 (2007) 016004 ) B Physics @ Tevatron / S.Burdin 11 Semileptonic Bs asymmetry Γ Bs (t ) f Γ Bs (t ) f a Γ Bs (t ) f Γ Bs (t ) f s sl • asfs=assl=ΔΓs/Δms tan(φs) • New Physics parameterization (A.Lenz&U.Nierste) M12 M12 s SM ,s Δs Δs e Δs iφsΔ Δms ΔmsSM Δs 19.30 6.74ps 1 Δs sin φ 4.97 0.94 10 ΔΓs 2 Γ12s cos φsSM φsΔ 0.096 0.039ps 1 cos φsSM φsΔ a s fs s Γ12 SM,s M12 SM s Δs φsΔ 3 sin φsSM φsΔ Δs Δs 1 and φsΔ 0 SM: • assl is very small in the SM: +2·10-5 • Estimate from ΔΓs, ΔMs and φs: assl=-(8.4+5.2-6.7)·10-3 19 Jan 2010 B Physics @ Tevatron / S.Burdin 12 Semileptonic Bs asymmetry • Semileptonic samples at D0 – BsμφπX: 81 394±865 (5fb-1) – BsμK*K: 33 557±1200 (5fb-1) arXiv:0904.3907 (submitted to PRL) 2 t Direct : Bs0 (t ) X N f Af e st cosh s cosM s t 2 2 2 t Mixed : Bs0 (t ) X N f Af 1 asls e st cosh s cosM s t 2 2 1 2d 1 d 1 d B (t ) f B (t ) f 2 2 1 2d P Bs0 (t ) f P 19 Jan 2010 µφ subsample 0 s B Physics @ Tevatron / S.Burdin 0 B s (t ) f 0 s 13 Semileptonic Bs asymmetry results 19 Jan 2010 B Physics @ Tevatron / S.Burdin 14 Flavor Changing Neutral Current processes • FCNC decays are forbidden in the tree level in the SM – Rates are highly suppressed in SM W- b uct s • NP allows tree level processes and enhancement in loops b s l’i23 ν~ b χ- s ~ ~ u c~ t • Dimuons in final state allow efficient trigger • Normalization to well known process with large statistics and similar final state N sig norm f norm BR(sig X ) BR(norm X ) N norm sig f sig 19 Jan 2010 B Physics @ Tevatron / S.Burdin 15 (*) BK μμ and Bsφμμ • 4.4fb-1 • Normalization to J/ψ+h where h=K,K*,φ 19 Jan 2010 B Physics @ Tevatron / S.Burdin 16 Relative BR BR(B+K+µ+µ-)106 CDF BR(B0K*0µ+µ-)106 BR(BSφµ+µ-)106 0.38 0.05(stat) 0.03(syst) 1.06 0.14(stat) 0.09(syst) 1.44 0.33(stat) 0.46(syst) HFAG 0.08 0.520.07 0.15 1.050.13 N/A CDF note 10047 Precision is comparable or better than WA BSφµ+µ- 1st observation! The rarest observed BS decay! Agrees with theoretical expectation: 1.6110-6 (C.Q.Gengand C.C.Liu, J.Phys.G29:1103-1118,2003) Statistics is enough to measure the differential BR, K* polarisation and Forward-Backward asymmetry 19 Jan 2010 B Physics @ Tevatron / S.Burdin 17 B0K*0µµ Forward-Backward asymmetry AFB (q 2 ) (q 2 , cos( ) 0) (q 2 , cos( ) 0) (q 2 , cos( ) 0) (q 2 , cos( ) 0) W.-S. Hou et al., PRD 77, 014016 (2008) 4th generation 19 Jan 2010 B Physics @ Tevatron / S.Burdin 18 B(s)μμ SM: Br(B0s→μ+μ-) = (3.6 ± 0.3)x10-9 Buras, arXiv:0904.4917 Br(B0d→μ+μ-) = (1.1 ± 0.1)x10-10 suppressed by (Vtd/Vts)2 NP: Br could be enhanced up to 100x b l’i23 s 19 Jan 2010 n~ l i22 B Physics @ Tevatron / S.Burdin 19 B(s)μμ analysis • • • • CDF: 3.7fb-1 DØ: 5fb-1 (expected limit) Normalization to B+J/ψK+ Selection optimization: – CDF: Neural Network – DØ: Boosted Decision Tree 19 Jan 2010 B Physics @ Tevatron / S.Burdin 20 B(s)μμ results DØ note 5906 • DØ (expected @5fb-1): – Br(Bsµµ)<4.3(5.3)10-8 90%(95%)C.L. CDF note 9892 • CDF (preliminary @3.7fb-1): – Br(Bsµµ)<3.6(4.3)10-8 90%(95%)C.L. – Br(Bdµµ)<6.0(7.6)10-9 90%(95%)C.L. 19 Jan 2010 B Physics @ Tevatron / S.Burdin 21 History & Projection for Bsµµ 19 Jan 2010 B Physics @ Tevatron / S.Burdin 22 Br(BSφφ) • Displaced tracks trigger • Normalization to BSJ/ψφ • Using 2.9fb-1 CDF observed 295±20 events and measured Br(BSφφ)=(24.0±2.1±2.7±8.2)10-6 (consistent with SM) http://www-cdf.fnal.gov/physics/new/bottom/090618.blessed-Bsphiphi2.9/ 19 Jan 2010 B Physics @ Tevatron / S.Burdin 23 Summary • The CP violation results from the Tevatron show some hints of deviation from the SM • The Tevatron FCNC analyses reached the sensitivity necessary to test the NP contributions to the rare B decays • The data to be collected in 2010-2011 could be golden for the B physics 19 Jan 2010 B Physics @ Tevatron / S.Burdin 24 Backup Slides DZero Detector • Spectrometer : Fiber and Silicon Trackers in 2 T Solenoid • Muons : 3 layer system & absorber in Toroidal field • Hermetic : Excellent coverage of Tracking, Calorimeter and Muon Systems Toroid & solenoid polarity flipped regularly Low background single and dimuon triggers large BμX semileptonic samples Detector asymmetries • Detector asymmetries were taken into account using a technique developed for the dimuon analysis Aμ=(1+qγAfb)(1+γAdet)(1+qβγAro)(1+βγAβγ)(1+qβAqβ) q – muon charge γ – sign of muon η direction β – toroid polarity 8 samples allow to determine all detector asymmetries CDF Detector • • th 4 Generation helps! Explains large CPV in Bs mixing Explains the Kπ puzzle in Bu/Bd: ΔA=AK +π0-AK +π -~15% • Baryon asymmetry due to the new CKM4 matrix could gain ~10+15! Global fits A.Lenz&U.Nierste • The asl contributions are weak B0K*0µµ Forward-Backward asymmetry BaBar, Phys. Rev. D79, 031102 (2009) BELLE, Phys. Rev. Lett. 103, 171801 (2009)