Rare decays at the Tevatron HCP2008 Brendan Casey, FNAL on behalf of CDF and DØ

1. Rare decays at the TevatronHCP2008Brendan Casey, FNALon behalf of CDF and DØ B. Casey, Rare Decays at the Tevatron, HCP2008

2. Motivation • Currently very good agreement between low energy phenomena and no new TeV scale physics • Two ways to address this • Closer look at places where there are disagreements (ns hints) • Look in regions we haven't focused on in the past • Will try and give a few example of each from heavy flavor decay measurements at the Tevatron B. Casey, Rare Decays at the Tevatron, HCP2008

3. Tevatron data sets B→Dp→Kpp Large top samples Huge B samples Enormous charm samples tt → l + jets Bs→Dsmn→fpmn D*→Dp→Kpp D*→Dp→Kmnp B. Casey, Rare Decays at the Tevatron, HCP2008

4. Tevatron experiments • Both have strengths • CDF displaced track trigger, DØ muon system • Both have weaknesses • p0 reconstruction B. Casey, Rare Decays at the Tevatron, HCP2008

5. Motivation • Currently very good agreement between low energy phenomena and no new TeV scale physics • Two ways to address this • Closer look at places where there are disagreements (ns hints) • Look in regions we haven't focused on in the past • Will try and give a few example of each from heavy flavor decay measurements at the Tavatron Charmless two body B decay B. Casey, Rare Decays at the Tevatron, HCP2008

6. Diagram level B→hh Several manifestations of b→s or b→d penguins interfering with b→u tree u b s,d s,d b u u u Simple CKM and SU(2) or SU(3) relates partial rate asymmetries among different modes B. Casey, Rare Decays at the Tevatron, HCP2008

7. Sometimes SU(3) works! Numbers from HFAG Winter 2008: Cross checks between neutral B meson decays seems to work fine B. Casey, Rare Decays at the Tevatron, HCP2008

8. Sometimes it doesn’t? Numbers from HFAG Winter 2008: > 5s difference CPV looks different in charged and neutral B mesons? QCD not ruled out as the culprit Experimentally, need to keep looking B. Casey, Rare Decays at the Tevatron, HCP2008

9. Charmless 2-body Lb decay • Quark level diagrams of Lb→ pK and pp equivalent to Bd→pK and pp • But Lb doesn’t mix • Allows to test if Kp puzzle is due to new physics in mixing • The type that effects all mixing measurements so it doesn’t mess up CKM triangle • Also main motivation for CPV studies in B→DK B. Casey, Rare Decays at the Tevatron, HCP2008

10. Lb signal extraction Tighter requirements optimized for Lb selection 2 displaced track trigger sample ~6.5 k ‘B’→ h+h- pK pp Clear excess in Lb region B. Casey, Rare Decays at the Tevatron, HCP2008

11. p/K/p separation Combination of info from invariant mass, dE/dx, and momentum asymmetries used to separate particle species Momentum asymmetry pK pp B. Casey, Rare Decays at the Tevatron, HCP2008

12. Results Too early to make strong conclusions but should be more interesting with more data B. Casey, Rare Decays at the Tevatron, HCP2008

13. Motivation • Currently very good agreement between low energy phenomena and no new TeV scale physics • Two ways to address this • Closer look at places where there are disagreements (ns hints) • Look in regions we haven't focused on in the past • Will try and give a few example of each from heavy flavor decay measurements at the Tavatron The up quark sector B. Casey, Rare Decays at the Tevatron, HCP2008

14. Down versus up t W c b, b΄ up line q = 2/3 Mass (MeV/c2) down line q = -1/3 s, s΄ d, d΄ u Generation B. Casey, Rare Decays at the Tevatron, HCP2008

15. Down versus up • Different mass hierarchy • Different flavor structure • Up: strong = weak eigenstates • Down: strong ≠ weak eigenstates • m(t)>m(W): • Top doesn’t hadronize • SM FCNC large in B decay • M(b)<<m(W): • FCNC charm tiny, dominated by hadronic effects Bottom line: SM is so different for up and down sector, no reason to believe beyond SM should be the same and is possibly the opposite B. Casey, Rare Decays at the Tevatron, HCP2008

16. Top joins search for anomalous FCNC Search for t→Zq t versus s channel single top production q q Z Z c.u t c.u t B. Casey, Rare Decays at the Tevatron, HCP2008

17. Also competitive charm results Radiative decay Charm mixing m c u Z m Z u c u c B. Casey, Rare Decays at the Tevatron, HCP2008

18. D0→mm GIM suppressed SM • Good mode to search for anomalous cuZ couplings or RPV • Excess would need to be disentangled from long distance effects • But we can worry about that when we have an excess • One of the first Tevatron RunII results based on 70 pb-1, now updated to 360 pb-1 • All about background reduction, particularly in this mode c m Beyond SM u m rescattering B. Casey, Rare Decays at the Tevatron, HCP2008

19. p/K fake rates Large peaking backgrounds from D0→hh decays. Can be determined precisely using D*’s 1% q = +1 K fakes m q = -1 D*→Dp+, D→K-p+ 1% p fakes m B. Casey, Rare Decays at the Tevatron, HCP2008

20. bb→mmX SV PV signal Remaining background is muons from semileptonic b decay. Can be removed with vertex quality and lifetime cuts PV background SV B. Casey, Rare Decays at the Tevatron, HCP2008

21. D0→mm results Analysis performed in 3 muon eta regions forward+forward central+forward central+central Expect 2.7±1.0 Observe 0 Expect 1.0±0.5 Observe 1 Expect 4.9±1.3 Observe 3 BF(D0→mm)<4.3 x10-7 @90% CL Best limit but still far away from SM B. Casey, Rare Decays at the Tevatron, HCP2008

22. Motivation • Currently very good agreement between low energy phenomena and no new TeV scale physics • Two ways to address this • Closer look at places where there are disagreements (ns hints) • Look in regions we haven't focused on in the past • Will try and give a few example of each from heavy flavor decay measurements at the Tavatron CPV in Bs mixing B. Casey, Rare Decays at the Tevatron, HCP2008

23. CKM & CPV CPV in J/yf Bd height ≈ 1 BS height ≈ 1/20 Im CKM axis Real CKM axis CPV in J/y Ks • The problem is: • CDF and DØ both see large CPV • CDF and DØ both have large errors CKM this is ≈ this UTFit claim > 3s using Tevatron J/yf, Asl, lifetimes, Bd info from B factories… B. Casey, Rare Decays at the Tevatron, HCP2008

24. CPV and Bs→Ds(*)Ds(*) Partial width difference between CP even and CP odd Bs decays ≈ saturated by the Bs→Ds(*)Ds(*) branching fraction No CPV Also traces out contour in DG/fs plane with CPV Projection from J/yf Projection from Ds(*)Ds(*) Not used in constraints b/c theory error uncontrolled Odd fraction of Ds(*)Ds B. Casey, Rare Decays at the Tevatron, HCP2008

25. Bs→Ds(*)Ds(*) Extracted using one semileptonic Ds decay and normalized to Bs→Dsmn Signal extracted from 2-D fit to m(Ds)-m(f) plane p m(KKp) g K Bs K DsDs K K g m n m(KK) B. Casey, Rare Decays at the Tevatron, HCP2008

26. Bs→Ds(*)Ds(*) ~10% Residual backgrounds from Bu,d and Bs semileptonic decay subtracted by looking in 2-D m(fm)-m(Dsfm) plane B→DsDsKX Bs→Dsfmn B. Casey, Rare Decays at the Tevatron, HCP2008

27. Bs→Ds(*)Ds(*) DØ RunII Preliminary Experimental error dominated by large difference in muon spectrum between Ds and Bs semileptonic decay Data simulation Dsm yield versus m pT pT(m) DØ RunII Preliminary DsDs/Dsm versus m pT pT(m) 5 GeV pT(m) B. Casey, Rare Decays at the Tevatron, HCP2008

28. Bs→Ds(*)Ds(*) results Stats at 2.8 fb-1 Accelerator division will reduce this Sys dominated by input Bs and Ds BFs Need help from CLEO-c and Belle ϒ(5S) Theory error not quantified Need help from theory, Belle ϒ(5S), and possibly our own data to limit odd fraction B. Casey, Rare Decays at the Tevatron, HCP2008

29. Conclusions • Tevatron experiments very active in decay studies of all heavy quarks • Adding information on existing puzzles • Kp puzzle with Lb, Bs two body decay • fs withDs(*)Ds(*) • Looking in uncharted regions only accessible at the Tevatron • Rare top and ultra rare charm B. Casey, Rare Decays at the Tevatron, HCP2008