1. Kai Yi, BaBar/SLAC1 e + e - Annihilation into Quasi-two-body Final States at 10.58 GeV --Expected or unexpected? Introduction Analyses of exclusive processes: --e + e -    ,   (C=+1) TVPA --e + e -  +  - (C=  1 ? ) 1  *+TVPA FSI? --e + e -  (C=  1 ) s dependence --e + e -  p  p p  p fragmentation (very preliminary) Summary Outlook Kai Yi, SLAC

2. Kai Yi, BaBar/SLAC2 Introduction—General Information  (e+e-  hadrons) ~ 3 nb @10.6 GeV The design goal of the B factory is the study of B physics. At  s~10.6 GeV,  (e + e -  hadrons) ~3 nb and ~8 Large integrated luminosity (~500 fb -1 )  can study low-multiplicity exclusive hadronic processes with  values ~fb; this provides tests of pQCD at the amplitude level. PDG 2006 Hadronic cross section

3. Kai Yi, BaBar/SLAC3 The BaBar Experiment  e  e   collisions at 10.6 GeV, designed for CP violation in B decays  Different beam energies:  E e   = 9.0 GeV  E e   = 3.1 GeV  c.m.-lab boost,  =0.55  Asymmetric detector  track coverage [/4  ]~0.92  EMC coverage [/4  ]~0.90  with excellent performance  High luminosity:  Good tracking, mass resolution  ~ 480 fb -1 accumulated  Good ,    reconstruction.  1.6 billion e  e   q  q evts  Good e, , ,K,p ID  0.5 billion e  e   B  B evts Data sample for today:  L ~343 fb -1 @10.58 GeV (OnPeak);  L ~36 fb -1 @10.54 GeV (OffPeak)  Barrel now has LSTs

4. Kai Yi, BaBar/SLAC4 Data input and physics output Peak luminosity (cm -2 s -1 ) 1.201 x 10 34 Best shift329.7 pb -1 Best day891.2 pb -1 Best week5.25 fb -1 Best month18.83 fb -1 BABAR logged477 fb -1 Run 6 BABAR Luminosity477fb -1 Journal Papers312

5. Kai Yi, BaBar/SLAC5 Introduction—Processes at B Factories One photon processes Two photon processes Two-Virtual-Photon-Annihilation, TVPA; new observation A subset of e + e -  q  q processes; or via ISR, a test ground for QCD B physics orh M1M1 M2M2 Low multiplicity  ~nb  ~fb C=  C=+ ** ** ** ** Exclusive hadronic final states TP Today’s topic

6. Kai Yi, BaBar/SLAC6 Observation of e + e -     /   (C=+1)

7. Kai Yi, BaBar/SLAC7 Observation of e + e -     /   (C=+1) PRL 97, 112002 (2006) @10.6GeV Select events with invariant mass of (K + K -  +  - /  +  -  +  - ) within 170 MeV of c.m. energy. We are interested in    . assume m(  0 )<2.2 GeV/c 2, p*(  0 )>4.8 GeV/c Only one entry in the region of interest (no ambiguity) p*  1  2 p*  1  4 4.8 GeV No entry Data

8. Kai Yi, BaBar/SLAC8  at 10.6 GeV, large kinematic separation between modes ...and between “correct” and “incorrect” pairings  e + e -     /   --generate level simulation

9. Kai Yi, BaBar/SLAC9 e + e -     /   --scatter plots in data signal tiles: 0.5<m  <1.1 GeV/c 2 (  ) 1.008<m KK <1.035 GeV/c 2 (  ) Use binned log-likelihood fit over 9 tiles to extract signal Including components:  KK  +  +  f 2 (1270) +  Threshold lego

10. Kai Yi, BaBar/SLAC10 f2f2  +  - against “  ”  +  - against “  ” K + K - against “  ” Correlated  and  0 signals Relativistic Breit-Wigner lineshapes used in the fit e + e -     /   --mass projections f2f2   total background  background  background+f 2 total

11. Kai Yi, BaBar/SLAC11 All Events Yield @ 10.58 GeV Yield @ 10.54 GeV Expected continuum @ 10.56 GeV (from  L ratio) 00 00 1243  43 >> 5  1138  42104  14112  4  0 147  13 >> 5  135  1314  413  1 consistent The extracted signals: C parity conservation  Y(4S) production do not contribute Consistent with continuum production  combine On- and Off-resonance data. Signals large enough to analyze the angular distributions and investigate the production mechanism for these final states. First observation of (C=+1) hadronic final states in e + e - collision. Likely by TVPA. significance Yield e + e -     /   --On-, Off-resonance comparison

12. Kai Yi, BaBar/SLAC12 e + e -     /   --TVPA expectation for cos  *   where 11 Production angular distribution due to TVPA: Both amplitudes are proportional to inverse of electron propagator:

13. Kai Yi, BaBar/SLAC13 Production angle  *  polar angle of  or  forward in CM consistent with expectation for TVPA 00 00  H for  + 1+cos 2  * for comparison e + e -     /   --Angular distributions in data Efficiency-corrected projections sin 2  H distributions as expected For TVPA with quasi-real photon    Helicity angle  H —the angle between daughter and recoil in the mother rest frame  0  H for  +  H for K +

14. Kai Yi, BaBar/SLAC14 The observed angular distributions support TVPA production: The measured cross sections (1.008<m  <1.035 GeV, 0.5<m  <1.1 GeV, |cos  *|<0.8) :  (  0  0 )=20.7  0.7(stat)  2.7(syst) fb reminder:  (  0 ) = 5.7  0.5(stat)  0.8(syst) fb  (e + e -  hadrons @10 GeV) ~ 3 nb Theory calculations (after the measurement) consistent with our results: hep-ph/0606155 hep-ph/0608200  (  0  0 )= 21.4  0.7 17.7  0.6 fb  (  0 ) = 6.0  0.1 5.6  0.2 fb e + e -     /   --Cross sections ** **

15. Kai Yi, BaBar/SLAC15 e + e -     /   --VMD model calculation Assuming the e + e − →  *  * process followed by conversion of  * into V 1 and V 2, with effective coupling e/f 1 and e/f 2. The cross section in c.m. frame can be written as: Obtain effective coupling through meson’s leptonic width: Calculation with this simple VMD model agree with our measurements. More calculations based on VMD are summarized in next slide: M. Davier et al, hep-ph/0606155

16. Kai Yi, BaBar/SLAC16 e + e -     /   --VMD model calculation Belle first observed J/   c (c  c) at a level 10 times higher than QCD prediction through missing mass recoiling against the J/ . J/  J/  was once proposed to explain the high rate. Its cross section was estimated to be ~ 7 fb, now ~2.5 fb (hep-ph/0608200). Not yet observed. hep-ex/0506062 J/ 

17. Kai Yi, BaBar/SLAC17 TVPA contribution to muon (g-2) is small with the current precision by extending our results to low energy Removes a possible uncertainty source in g-2 calculation  2 /  (pi-rhonium, mixing of  and pionium)? 0705.0757[hep-ph] e + e -     /   —VMD model calculation Discrepancy between  decay data and e + e - data as input. Interpretation of e + e - cross section ignores C=+1 process. How much TVPA contribute? One of our motivations Eur. Phys. J. 31, 503-510 (2003)Spectral function R value from e + e -  VV(C=+1), |cos  *|<0.8, (hep-ph/0606155)

18. Kai Yi, BaBar/SLAC18 Observation of e  e  →    

19. Kai Yi, BaBar/SLAC19 Observation of e  e  →     Single photon (J PC = 1 -- ) Other possibility: TVPA (C = +1) followed by FSI → unlikely?   In general: C(  +  -)=(-1) L+S, + or -; P(  +  - )= (-1) L ; Single photon production  L odd, S even, I(  +  - )=1(Bose Statistics). No angular correlation predictions for this mechanism     u u u u d u d u 379 fb -1, BaBar Preliminary

20. Kai Yi, BaBar/SLAC20 Three independent helicity amplitudes: F 00, F 10, F 11, if one  * production assumed. One QCD model predicts (PRD 24, 2484) s dependence and production angle:  F 00  1/s 2, sin  *2 ;  F 10 <1/s 3, 1+cos  *2 ;  F 11 <1/s 3, sin  *2 ; @10 GeV, F 00 is expected to dominate. Test QCD at the amplitude level in helicity structure. Select:  two tracks:    and    two good     momentum balance, m     < 1.6 GeV/c2  |m         - E CM |<280 MeV e  e  →     —QCD prediction and event selection

21. Kai Yi, BaBar/SLAC21 Clear signal for e  e  →     2D Likelihood Fit in (m  -  0, m  +  0 ) plane: Signal function= product of P-wave relativistic BWs  = threshold function Linear combinatorial background Mass projections e  e  →     —Scatter plot and mass projections

22. Kai Yi, BaBar/SLAC22 We observe 308 ± 25 signal events (> 5  ). (fiducial) cross section is 8.5±0.7±1.5 fb (|cos  *|<0.8, |cos   |<0.85, 0.5<m   <1.1) Extend to full angular range assuming 1  * production:  (e + e - →  +  - ) = (20.0 ± 1.6 ± 3.6 ± 1.7) fb preliminary (no prediction)  (e + e - →  0  0 ) ~ 130 fb hep-ph/0606155  (e + e - →  0  0 )>>  (e + e - →  +  - ); FSI possible explanation? No evidence for Y(4S) →  +  -. e + e - →  +  - seen in ISR data; e + e - →  0  0 is not seen in ISR as expected. Will study cross section s dependence using ISR data and this result. e  e  →     —Cross section

23. Kai Yi, BaBar/SLAC23 Assuming one-virtual-photon (J PC =1 - - ) production, the total spin S and orbital angular momentum L should satisfy (in L-S coupling):   *--production angle,  * is not well defined (beam depolarization)  + --  + helicity angle,  + --  + azimuthal angle Similar for  - Our coordinate system: e-e- ** ++ ** ++ -- ++ ++ ** e  e  →     —Coordinate system

24. Kai Yi, BaBar/SLAC24 In helicity basis, the decay amplitude of a two-body decay (PRD 57 431, 1998) : Can be expressed as: e  e  →     —Angular correlation calculation

25. Kai Yi, BaBar/SLAC25 In terms of J P, e  e  →      can be expressed as 1 -  1 - 1 -, we have the following helicity configurations (, ): (1,1), (1,0), (-1,-1),(-1,0), (0,1), (0,-1),(0,0), (1,-1), (-1,1) (angular momentum). The remaining possible amplitudes are: F 11, F 10, F -1-1, F -10, F 01, F 0-1, F 00  CP conservation  e  e  →     —Angular correlation calculation i.e. only 3 independent amplitude

26. Kai Yi, BaBar/SLAC26 I~|A| 2, complicated angular distribution. Due to low statistics, we only investigate individual angular projection by integrating over the other angles: By integrating, we lose strong phase information. The most separation power is from dN/dcos  . The F 00 amplitude contribution goes to zero for   =90 o. The amplitudes are correlated; intensive Toy MC has been done to validate the procedure. No bias is found from Toy MC studies. e  e  →     —Angular correlation calculation

27. Kai Yi, BaBar/SLAC27 Efficiency corrections to angular distributions: --non-flat dependence of  on cos  * and cos   --use a 3D(cos  *,cos  +,cos  - ) table to correct each event --the method is validated on an independent MC sample. Background subtraction using sPlot --weight each event by sWeght obtained from 2D mass fit --consistent with conventional way. Weight each event by sWeight and  to produce signal angular distributions. e  e  →     —  correction and background subtraction

28. Kai Yi, BaBar/SLAC28 e  e  →     —Fit to the projected angular distributions BaBar Preliminary Helicity angle Production angle Azimuthal angle Simultaneous fit to the five distributions. F 00 dominates but Cannot explain all pQCD predicted |F 00 |~=1, and Non-zero amplitude  |F 00 | =1

29. Kai Yi, BaBar/SLAC29 Results: Fit normalization constraint: |F 00 | 2 ≠ 1,  (e + e - →     ) >  (e + e - →     ); no evidence for Y(4S) →  Are we seeing TVPA + FSI? --Combine with ongoing ISR analysis to measure s dependence of the cross section for each individual amplitudes to investigate FSI. Any connection between B  VV polarization puzzle and e+e-  VV? e  e  →     —Amplitude result x4 x2 --Prediction: --BaBar Data:

30. Kai Yi, BaBar/SLAC30 Observation of e + e -  at ~10.6 GeV

31. Kai Yi, BaBar/SLAC31 e + e -   is analogous to e + e -  J/  c (  has s-sbar content) Interesting because observed  (e + e -  J/  c ) 10x higher than QCD predictions Provides information on s-dependence by combining with a CLEO measurement at lower energy Select: -- exactly two tracks, identified as K + and K - --two good g candidates with deposited energy greater than 500 MeV --momentum |p K + K -  |<0.2 GeV/c in the c.m. frame -- a pairing with both m K + K - <1.1 GeV and 0.4<m  < 0.8 GeV/c2 --select events within 230 MeV of the nominal E CM Observation of e + e -  at ~10.6 GeV PRD (RC) 74, 111103(2006)

32. Kai Yi, BaBar/SLAC32 e + e -  --Signal and scatter plot PRD (RC) 74, 111103(2006) @ 10.58 GeV@10.58+10.54 GeV   We see  correlation. Use a two-dimensional log-likelihood fit to extract signal: P-wave relativistic Breit-Wigner for  ; Gaussian resolution function for 

33. Kai Yi, BaBar/SLAC33 Yield for 1.008<m  <1.035 GeV/c 2, and 0.4<m  <0.8 GeV/c 2 : All data: 24  5 events @10.58 GeV: 20  5 @10.54 GeV: 3  2 Significance: 6.5  U.L. for BF of Y(4S) decay @90% CL based on -10  21 events: 2.5X10 -6 Mass projections e + e -  --Mass projections

34. Kai Yi, BaBar/SLAC34 e + e -  --Coordinate system  (1 -- ),  (0 -+ ),  (1 -- ), P conservation  L=1, assuming one  * production. In helicity base, we have only one amplitude: F 10. (F 00 is forbidden due to vanishing CG coefficient) We have a similar coordinate system: We ignore the  decay angular distributions, they are flat. e-e- **  **    K+K+ **

35. Kai Yi, BaBar/SLAC35 e + e -  --Angular correlation calculation Similarly, we can calculate the total helicity amplitude as:

36. Kai Yi, BaBar/SLAC36 Weight isotropic MC angular distributions as above to obtain efficiency estimates. The efficiency dependence for each angular distribution is approximately flat, which simplify the correction procedure. Distributions in data are consistent with predictions within the limited statistics e + e -  --Angular distributions Due to low statistics, we investigate the angular projections by integrating over the other angles:

37. Kai Yi, BaBar/SLAC37 For 1.008<m  <1.035 GeV/c 2 and |cos  *|<0.8, the cross section after radiative corrections is measured as:  (  )=2.1  0.4(stat)  0.1(syst) fb Extending to (|cos  *|<=1) by assuming a 1+ cos 2  * distribution, this becomes:  (  )=2.9  0.5(stat)  0.1(syst) fb Combine with CLEO measurement at lower energy; 1/s 3 energy dependence favored over 1/s 4 (pQCD prediction), assuming continuum production. Analysis of BaBar ISR data is ongoing; see preliminary result next slide. e + e -  --Cross section Recent theory prediction (after the measurement) (hep-ph/0702065):  ~3.1~4.3 fb, and 1/s 3 dependence favored.

38. Kai Yi, BaBar/SLAC38 e + e -  --Preliminary result from ISR BaBar preliminary ISR (  ISR KK  ) result possible structure(s) near 2.2 GeV At “high”-E CM, data (including 10.6 GeV point) are consistent with 1/s 4 CLEO measurement seems to be low. Dispersion relation phenomenology EPJ A31, 665 (07) --explains the data nicely in terms of  ’ and  ’ resonances --confirms 1/s 4 asymptotic behavior, it is actually helicity F 10 amplitude implies that pQCD is right, favor FSI for e  e  →      BaBar Preliminary

39. Kai Yi, BaBar/SLAC39 Connection to LHC Angular correlations to determine J PC of X(H) particle --Simple way: assume one configuration, compare to data --General way: assume all configuration, decide the best one. e.g., X(H)  ZZ sPlot to subtract background. i.e., H  ZZ (may not needed) Test PYTHIA prediction. Help refine the fragmentation model of PYTHIA for a more precise modeling of the jet content. Even the energy at BaBar is low compare with LHC, but we have information from data.

40. Kai Yi, BaBar/SLAC40 Summary At BaBar we have: Made the first observations of the TVPA hadronic processes: e + e -     and e + e -   and the angular distributions support TVPA mechanism. Observed the process e + e -  +  - ; the measured helicity amplitudes contradict a pQCD expectation at 3.5 , assuming single  * production. --Further investigation using ISR data on e + e -  +  - will provide information on the s dependence and perhaps on understanding of the role of FSI (if any). Observed the process e + e -  and measured the cross section; this provides an interesting test of the QCD prediction for the energy dependence, assuming continuum production. Observed e + e -  p  p p  p, presently being investigated.

41. Kai Yi, BaBar/SLAC41 Outlook We also see evidence of many other exclusive final states. Results from these channels will provide further detailed tests of QCD and hadronization models. However B factories provide opportunity to search for new particles. X(3872), Y(4260), Y(4350), Z(4430) +, Y(4660)… (unexplained) Z(4430) +, if confirmed, has strong implication for other states. May classify them as multiple-quark states, hybrid, glueball,… Glueballs and hybrids gain mass through the strong interaction (solely for glueball). A unique place to study: mass creation by strong interaction. (i.e., proton gains only a few percent of its mass through Higgs mechanism) lots of activities are going on…

42. Kai Yi, BaBar/SLAC42 Outlook More fundamental question: How bosons, fermions gain mass? The Higgs mechanism? Updated W and top quark masses improved constraint on Higgs mass: M H = 76 ± 31 GeV (  m H /m H  39%) (winter 07) LEP limit: >114.4 GeV @95% CL New possibilities proposed: --H  2a  X, a is non-SM particle. (hep-ph/0608310) --CP-Odd NMMSM A 0 .(hep-ph/0404200, hep-ph/0612031) (put BaBar in the game)

43. Kai Yi, BaBar/SLAC43 Outlook New idea at LHC: Flavor Changing Higgs Decays (FCHDs) BR is estimated to be about 10 -4 -10 -3 MSSM  (h 0,H 0,A 0 )  b  s, Phys. Lett. B 647, 36-42 (2007) QCD background free, challenge on s jet identification (impossible?) Trigger possible? Some ideas on s jet ID (no guarantee to work): --p T of K s /  /  /…? Anything else? hep-ex/9702009, hep-ex/9908038,… --impact parameter separates b (c) from s --Jet charge tagging separates up-type from down-type --use MVA technique to combine? --Topological Vertex help?? Thank you!

44. Kai Yi, BaBar/SLAC44 Backup—BaBar detector perfomance