1. Beach04 Chicago Peter Kluit Excited B states at LEP Peter Kluit (NIKHEF) DELPHI/LEP Introduction & history Theory Experimental overview Excited B u,d results Search for B s ** and  b ( * ) Summary

2. Beach04 Chicago Peter Kluit Introduction History Boom of B physics at LEP around 1994 vertex detectors exclusive reconstruction Discovery B s meson at LEP B baryons Precision lifetimes B d oscillations Event B s →  `  → KK

3. Beach04 Chicago Peter Kluit Inclusive B reconstruction New technique (~1994) High rapidity particles Secondary vertex Energy-momentum constraint Estimate B four-momentum Physics result : precision mass B * → B Production V/(V+P)=0.75  →e + e -

4. Beach04 Chicago Peter Kluit Discovery of excited B states Reconstruct B ** → B  Inclusive B fragmentation  OPAL 1995 Prel. 1997 B s **  b ( * ) OPAL 1995 1995

5. Beach04 Chicago Peter Kluit Theory HQET ljqjq JPJP stateDecay 0 ½ 0-1-0-1- B B* BB 1 ½ 0+1+0+1+ B* 0 B* 1 B B* 1 3/ 2 1+2+1+2+ B 1 B* 2 B*B(*)B*B(*) Heavy Q, light quark q s q q l → j q ; s Q q j q → J Charm system measured: Broad Narrow Expect B system m doublet ~m c m c /m b ~13 MeV  Broad y 300 MeV Similar for B s **, decay to B s * Isospin forbidden Dominant decay B s ** → B ( * ) K, if above threshold

6. Beach04 Chicago Peter Kluit B production at LEP production fractions adjusted to world average

7. Beach04 Chicago Peter Kluit Experimental overview B ud ** Experimentmethod m(B**) MeV (B**)/(b) OPAL 95Incl 5712 ± 11 0.22 ± 0.05 DELPHI 95Incl 5732 ± 5 ± 20 0.27 ± 0.02 ± 0.06 ALEPH 96Incl 5734 ± 3 ± 16 0.14 ± 0.01 ± 0.03 L3 99Incl B* 2 : 5768 ± 5 ± 6 0.32 ± 0.03 ± 0.06 CDF 01 Semi-excl B 1 : 5710 ± 20 0.22 ± 0.05 ± 0.02 ALEPH 98Excl B* 2 :5739 ± 11 ± 6 0.24 ± 0.07 ± 0.05 Some numbers recomputed using common inputs OPAL 01 Br(B **→ B* X)=0.85±0.26±0.12 Narrow states

8. Beach04 Chicago Peter Kluit Experimental issues Crucial treatment of background Taken from MC, except ALEPH exclusive analysis Induces high production rate, shifted mass peaks, instabilities ALEPH exclusive

9. Beach04 Chicago Peter Kluit New DELPHI B** analyses Focus on the background using control sample: High efficiency Reduction by neural networks: High purity Full LEP I statistics, reprocessed data, improved analysis techniques, inclusive B reconstruction b and anti b tagging B charge

10. Beach04 Chicago Peter Kluit Analyses steps Reconstruct weakly decaying B and combine with  from primary vertex Signal Background wrong sign B d ** → B +   B+B+ B u ** + → B 0   B0B0 Samples separated b/b tag q B vertex charge High Efficiency: soft cuts, signal/wrong sign similar shape High Purity: tight cuts, neural network

11. Beach04 Chicago Peter Kluit High efficiency Analysis Simultanous fit to signal and background B** signal Narrow: B* 2 mass and m(B* 2 -B 1 ) free Br(B * 2 → B *  /B    ±0.3 Broad : extrapol from Charm m(B* 1 )=m(B 1 ),m(B 1 -B 0 )=45 MeV =300(330) MeV Enhancement at Q~500 MeV, ~300 MeV (~2 s.d.) DELPHI

12. Beach04 Chicago Peter Kluit High purity analysis Fit background MC times polynome Signal resolution free parameter Largest Systematics Background parametrisation Energy scale Cuts NN rapidity Modeling: With/without 500-state Spin/state counting Fits not sensitive to Broad states and to spin/state counting (< 2 s.d.) Significant deviations MC at low and high Q values B0B0 B+B+

13. Beach04 Chicago Peter Kluit Summary of B** results Total rate (B** ud )/(b) (broad+narrow) MethTotal rateNarrow rate Q( B* 2 ) MeV m(B* 2 -B 1 ) MeV HEff 0.160 ± 0.012 ± 0.020 ± 0.025 0.091 ± 0.007 ± 0.013 ± 0.011 316 ± 9 ± 12 ± 9 -2 ± 15 ± 9 ± 11 HPur 0.153 ± 0.017 ± 0.038 ± 0.017 0.088 ± 0.009 ± 0.022 ± 0.011 323 ± 7 ± 13 ± 9 15 ± 13 ± 10 ± 6 Comb 0.157 ± 0.011 ± 0.022 ± 0.019 0.090 ± 0.007 ± 0.013 ± 0.011 319 ± 6 ± 9 6 ± 11 ± 7 ± 6 (stat) (sys) (model) m(B* 2 )=5738 ± 14 MeV and m(B 1 )=5732 ± 20 MeV DELPHI preliminary

14. Beach04 Chicago Peter Kluit Comparison of LEP Results Rate  (B** ud )/  b) (narrow)~factor 1.5-2 lower Due to background treatment, inclusive analyses at LEP overestimate the rate Compatible with ALEPH exclusive analysis m(B* 2 )=5739 ± 10 MeV DELPHI:5738 ± 14 MeV Total rate=0.24 ± 0.07 ± 0.05 DELPHI:0.157 ± 0.011 ± 0.029 Compare to (D** narrow )/(c) = 0.17 ±0.05 FUTURE recommend exclusive analyses extracting the background from data

15. Beach04 Chicago Peter Kluit DELPHI B** s search Channel B s ** → B ( * )+ K - Using neural networks for identification of kaon and B vertex charge Fit signal (Gaussian), free background Total Significance 3.8 systematics included Background shape Identification K/ NN Energy scale

16. Beach04 Chicago Peter Kluit Interpretation & discussion Most likely B s2 * → B K - (B*K reduced by factor 10) B s1 Puzzle: Large m? Enhanced B s1 → B s *? Results m(B s2 * )=5852 ± 5 MeV OPAL: 5800-5900 MeV Rate (B s2 * )/(b)= 0.0093±0.0020±0.0013 OPAL: 0.020 ±0.006 Where is B s1 → B*K? m 13 MeV DELPHI preliminary

17. Beach04 Chicago Peter Kluit DELPHI  b ( * ) search Channel  b ± ( * ) →  b  ± Using neural networks for identification B baryon Fit signal, free background S qq J bb 0 ½ bb 1 ½ b*b* 1 3/23/2 Upper limit 95% CL  ( b ( * ) )/ (b) < 0.012 Preliminary Old prel. DELPHI result not confirmed

18. Beach04 Chicago Peter Kluit Summary New DELPHI measurements for B** ud Total production rate: (B** ud )/(b)=0.157±0.011±0.029 m(B* 2 )=5738 ± 14 MeV and m(B 1 )=5732 ± 20 MeV New results ~factor 1.5-2 lower than previous due to background Compatible with ALEPH exclusive, and charm production Search for B** s Signal at 3.8  with m(B s2 * )=5852 ± 5 MeV; B s1 Puzzle Production rate: (B s2 * )/(b)= 0.0093±0.0020±0.0013 Search for  b ( * ) Limit production rate:  ( b ( * ) )/(b) < 0.012 at 95% CL Preliminary