Searches for New Physics at BaBar Haleh Hadavand UC San Diego July 18, 2005 SUSY 2005 Conference

Searches for New Physics at BaBarH. Hadavand SUSY 052 This Talk will Cover  CP violation  The BaBar experiment  Gluonic Penguins  Radiative Penguins  Leptonic decays  Lepton Flavor Violation in  decays

Searches for New Physics at BaBarH. Hadavand SUSY 053 The Quark Mixing Matrix The only Standard-Model source of CP violation in the quark sector The Cabibbo-Kobayashi-Maskawa matrix relates the flavor ( q ′) and the mass ( q ) quark eigenstates: α γβ V td V tb * V cd V cb * V ud V ub * B 0 → π + π − B 0 → ρ + ρ − b → ulν b → clν B → ψK S B → φK S B 0 → D * π B + → D 0 CP K + B 0 B 0 mixing The “unitarity triangle” W+W+ q i = u,c,t q j ' = d',s',b' gV ij

Searches for New Physics at BaBarH. Hadavand SUSY 054 Time evolution of the B 0 meson The time-dependent rate for B 0 (  + ) or B 0 (  − ) decays to a final state f (neglecting the lifetime difference between the mass eigenstates B H and B L ): where,,, If f is a CP eigenstate, f CP, we have CP violation if λ f ≠ ±1: |q/p | ≠ 1 (CP violation in mixing, negligible in SM) |A f /A f | ≠ 1 (direct CP violation, small in b→ccs) Im(λ f ) ≠ 0 (interference between mixing and decay)

Searches for New Physics at BaBarH. Hadavand SUSY 055 PEP-II accelerator schematic and tunnel view The PEP-II Asymmetric B-meson Factory Most results presented are from: Run 1-2 = 88 M BB events Run 1-4 = 227 M BB events  (4S)  Peak luminosity: 9.21 x cm –1 s –2 (design: 3 x cm –1 s –2 ) Best 24 hours: 711 pb –1 (design: 135 pb -1 /day) Peak luminosity: 9.21 x cm –1 s –2 (design: 3 x cm –1 s –2 ) Best 24 hours: 711 pb –1 (design: 135 pb -1 /day) Run1-2 Run1-4 9 GeV 3.1 Gev

Searches for New Physics at BaBarH. Hadavand SUSY 056 The BaBar Detector 1.5 T solenoid Electromagnetic Calorimeter Lepton, photon,and  0 id Drift Chamber 40 layers (24 stereo) e + (3.1 GeV) e - (9 GeV) 9 meters Silicon Vertex Tracker Find B vertex 5 layer double sided strip detectors (z-  ) Cerenkov Detector (DIRC) kaon/pion id Instrumented Flux Return Muon id K L id z axis

Searches for New Physics at BaBarH. Hadavand SUSY 057 Time-dependent CP analysis at a B-meson factory B-flavor tagging Exclusive B-meson reconstruction Y (4S) produces a coherent pair of neutral B mesons ~260 μm Δ z (BaBar)

Searches for New Physics at BaBarH. Hadavand SUSY 058 Kinematic Variables m ES resolution dominated by beam energy spread 2.5 MeV/c 2  E resolution depends on detector energy resolution and final particles in decay In CM of Y(4s) Energy substituted mass Energy Difference

Searches for New Physics at BaBarH. Hadavand SUSY 059 Results for B  J/  K 0 (cc) K S modes (CP =  1) background “Golden Mode” 4370 CP = −1 tagged events, signal purity ≈ 90% 7730 total tagged events, signal purity ≈ 76% Phys. Rev. Lett. 94, (2005) sin(2β) ccs = ± ± 0.023

Gluonic Penguins

Searches for New Physics at BaBarH. Hadavand SUSY 0511 Gluonic Penguin Decays B0  η′K 0,K + K − K 0,π 0 π 0 K s, K s K s K s B 0  η′K 0,K + K − K 0,π 0 π 0 K s, K s K s K s, ωK, f 0 KKπ 0,φK 0, ωK S, f 0 K s, K s π 0,φK 0  Gluonic penguins good way to probe new physics  New particles in the loop can cause deviations from SM diagrams  Dominated by top quark in loop Expect same time-dependent CP violation as in b  ccs decays Small direct CP asymmetry  Some modes more theoretically clean than others as we will see Estimates from QCDF and SU(3) Standard Model SUSY

Searches for New Physics at BaBarH. Hadavand SUSY 0512 B0 K +K−K0B 0 K +K −K0B0 K +K−K0B 0 K +K −K0 Phys. Rev. D 71, (R) (2005) hep-ex Phys. Rev. D 71, (R) (2005) hep-ex KKK L : Nsig=777  80 Combined KKK L and KKK S NSig=1229 events CP content in KKK L sample: f(P-wave) = 0.92  0.07  0.06 BABAR KKK 0 QCDF SU(3) bound Cheng,Chua,Soni, hep-ph/ Grossman,Ligeti,N ir,Quinn, PRD M BB

Searches for New Physics at BaBarH. Hadavand SUSY 0513 B0  η′K0B 0  η′K0B0  η′K0B 0  η′K0 Phys. Rev. Lett. 94, (2005)  ’K L : Nsig=440 Combined  ’K L and  ’K s : Nsig=1245  67 BABAR  ’K 0 QCDF SU(3) bound 2.8  away from BaBar value of sin 2  =0.722  0.04 Beneke, hep-ph/ Grossman,Ligeti,Nir,Quinn, PRD M BB

Searches for New Physics at BaBarH. Hadavand SUSY 0514 B0  KSKSKSB 0  KS KS KSB0  KSKSKSB 0  KS KS KS The B CP production point is constrained to the beamspot in ( x, y ) e-e- ++ B tag - Standard Method e+e+ y z K0sK0s Ks0Ks0 -- ++ ++ -- -- K0sK0s  tag  z ~ 180 m Beam size 4  m in y and and 200  m in x Error on  t still dominated by tag side B About ~ 100% of events vertexed in 3K s (  +  - ) About ~97% of events vertexed in 2K s (  +  - )K s (      3K s (  +  - )2K s      K s      all events sPlot * sPlot [Pivk, Diberder, physics/ ]

Searches for New Physics at BaBarH. Hadavand SUSY 0515 B0  KSKSKSB0  KSKSKSB0  KSKSKSB0  KSKSKS N sig = 41± 9 Preliminary N sig = 88 ± 10 PRL (2005). Combined result Preliminary QCDF SU(3) bound Main Systematic uncertainty PDF parametriza tion Englehard, Nir, Raz hep-ph/ Cheng,Chua,Soni, hep-ph/ M BB

Searches for New Physics at BaBarH. Hadavand SUSY 0516 BKSBKS 70% of events with good Vertex Use NN to reduce continumm background Nsig=117  27 Preliminary Dominant syst. errors: - pdf shapes - Bkg composition and CP -  t resolution - fit bias 227 M BB

Searches for New Physics at BaBarH. Hadavand SUSY 0517 Summary of B A B AR Results No evidence for direct CP in these samples Intriguing difference from sin2b[cc] remains: naïve average 0.44  0.09 (~2.7  ) (BABAR Only)

Searches for New Physics at BaBarH. Hadavand SUSY 0518 New Combined sin2  Values Most theoretical calculations have positive deviations Avoid averaging all modes since effected by different errors  ’K s and  K s modes with smallest uncertainty Errors from QCD factorization [Beneke, hep-ph/ ] [Cheng,Chua,Soni, hep-ph/ ]

Radiative Penguins (*)(*)

Searches for New Physics at BaBarH. Hadavand SUSY 0520 New particle in loop can change both the rate and phase SM: Photon approx left handed Other: Theories more L-R symmetric Radiative Penguins B → K* , , , Kll B 0 →  0 , , D* 0 , … B + →  + , … Nucl. Phys B 631, 219 (2002)) Good agreement for inclusive modes Exclusive decays have more theoretical uncertainties, form factors needed BaBar Preliminary

Searches for New Physics at BaBarH. Hadavand SUSY 0521 B  K*  Direct CP asymm: A CP =   No isospin breaking from the dominant penguin diagram In the K *  mode:    ~ 5 – 10 % (*): Errors stat.+syst.+uncertainty on B + /B 0 production ratio * B(B 0 →K *0  ) = (38.7  2.8  2.6) x B(B + →K *+  ) = (39.2  2.0  2.4) x PRD 70, (2004) Can bound |V td /V ts | from ratio below:  R is different in dynamics such as W annihilation  0.1 form factor ratio  R is different in dynamics such as W annihilation  0.1 form factor ratio Ali and Parkhomenko, Eur.Phys.JC 23,89 (2002) Ali et al, PLB 595,323 (2004)

Searches for New Physics at BaBarH. Hadavand SUSY 0522 Search for B →  Simplest and most “common” b  d  exclusive decays 22 Simultaneous fit to all three samples with the constraint: PRL 92, (2004)  =50%  =46%  =42% B0 → 0B0 → 0 B+ → +B+ → + B0 → B0 →  A total of 211M BB Simultaneous fit to all 3 modes

Searches for New Physics at BaBarH. Hadavand SUSY 0523 B →  :CKM Constraints Theoretical limits : Must be close to discovery of decays Ratio of exclusive b  s  and b  d  modes provides useful CKM limits With theory error Without theory error

Searches for New Physics at BaBarH. Hadavand SUSY 0524 Measurement of B  K (*) l + l - EW penguin SM diagramsSUSY diagram New Physics can change enhance R K/K* value direct CP violation forward-backward di-lepton asymmetry See for instance Ali et al, Phys. Rev. D 66, (2002) See for instance Ali et al, Phys. Rev. D 66, (2002) W + W – box  SM predictions Suppressed decays (BF  ), negligible direct CP asymmetry R K  BF(B  K      ) / BF(B  K  e + e  )  1 R K*  BF(B  K *      ) / BF(B  K *  e + e  )  0.75 Ratio of branching fractions predictions Contribution from a pole in EM penguin for the e + e  final state at q 2  0

Searches for New Physics at BaBarH. Hadavand SUSY 0525 B  K (*) l + l - Preliminary Results B  K*l+lB  K*l+l B  Kl+lB  Kl+l BF( B  K  l + l  ) = ( 0.34  0.07  0.03)  10  6 BF( B  K *  l + l  ) = ( 0.78  0.12)  10  6 BF( B  K  l + l  ) = ( 0.34  0.07  0.03)  10  6 BF( B  K *  l + l  ) = ( 0.78  0.12)  10  6 Preliminary  0.17 R K = 1.06  0.48  0.05 R K* = 0.93  0.46  0.06 R K = 1.06  0.48  0.05 R K* = 0.93  0.46  0.06 Preliminary A CP ( B +  K +  l + l  ) =  0.08  0.22  0.11 (*) A CP ( B  K *  l + l  ) = 0.03  0.23  0.12 (*) A CP ( B +  K +  l + l  ) =  0.08  0.22  0.11 (*) A CP ( B  K *  l + l  ) = 0.03  0.23  0.12 (*) Preliminary Crossfeed from B  Kl + l - events Tested that no bias is induced (*): Main systematics due to a conservative estimate of the peaking background asymmetry Consistent with SM hep-ex/ M BB

Searches for New Physics at BaBarH. Hadavand SUSY 0526 B  K   Up to m s /m b corrections, we expect in the SM:  A different polarization is a marker of new physics  It can be probed in Need 2 interfering amplitudes related by isospin: (K        K      M ES Gronau et al Phys. Rev. D66 (2002) hep-ex/ , preliminary

Searches for New Physics at BaBarH. Hadavand SUSY 0527 Time Dep-CP B 0  K*(K 0 s  0 )  Same vertexing technique as B 0  K 0 s K 0 s K 0 s Standard Model Expectations: B0B0 B0B0 K*  L K*  R In the SM, mixed decay to K*  requires wrong photon helicity Helicity Flip suppressed by ~m s /m b Mixing 156 +/- 16 events 59 +/- 13events hep-ex/ , submitted to PRD-RC

Leptonic Decays

Searches for New Physics at BaBarH. Hadavand SUSY 0529 BB New physics in B   Charged Higgs boson as propagator: SUSY, two- Higgs doublet models Enhancement of the B up to 5 times Measurement of f B Assuming |V ub | known from semileptonic decays Measurement of |V ub | 2 / |V td | 2 From B (B   m Constraints CKM matrix Experimentally challenging in final state

Searches for New Physics at BaBarH. Hadavand SUSY 0530 BB Exclusive reconstruction with a semileptonic B “tag” Search for a B   signal in the rest of the event   e                 E extra : Residual energy in Calorimeter Peaks at 0 for signal events Signal MC on-res Data – Background MC  +  e +  +   +  +   + misiden. lepton  +     +  

Searches for New Physics at BaBarH. Hadavand SUSY 0531 BB Preliminary, combined with hadronic tags B (B     )  2.6  10  90% C.L. f B  % C.L. Expected background  9.3 Observed events 150  12 Preliminary, semileptonic tag B(B     )  2.8  10  90% C.L. tan  m H  < 0.34 (GeV/c 2 )  Preliminary constraint on new physics tan  ratio of the vacuum expectation values for two-Higgs doublets Total of 232 M BB events used

Lepton Flavor Violation in  decays

Searches for New Physics at BaBarH. Hadavand SUSY 0533    /e   BaBar is also a  factory  In SM B(   e    from mixing and mass inclusion  However LFV is present in other theories at the order of GeV e GeV e +    Current most stringent experimental limits of that order J.R Ellis et al Phys. Rev. D 66, (2002). E. Ma, Nucl. Phys. Proc. Suppl. 123, 125 (2003).

Searches for New Physics at BaBarH. Hadavand SUSY 0534    /e  Preliminary hep-ex/ accepted by PRL Tag side  reconstructed in 6 modes-1-1 or 1- 3 prong topology Use Neural Network to reduce background in each mode after some initial cuts  /e constrained to e + e - collision axis 9.0 GeV e GeV e +  tag  rec  /e  Beam Energy constrained mass:

Searches for New Physics at BaBarH. Hadavand SUSY 0535 Summary Gluonic Penguins: sin 2  measured is less than charmonium; new theoretical bounds to interpret deviations;  ’K s and  K s modes to follow (*)(*) Radiative Penguins: CP asymmetries still statistics limited; b  s , sl + l - becoming precision measurements; B   close to discovery limit Leptonic Decay: B   consistent with SM; limit on f B < 0.41 GeV and tan  /M H <0.34 GeV LFV in  decays: New upper limit on   e  <1.1 x sensitivity at reach of New Physics

Searches for New Physics at BaBarH. Hadavand SUSY 0536 Backup Slides

Searches for New Physics at BaBarH. Hadavand SUSY 0537 Vertexing Constraints y x ~4  m Inflated Beam Beam ~200  m ++ K0sK0s ~30  m ++ -- K0sK0s ++ -- K0sK0s K 0 s have a long lifetime Can decay outside SVT or have few hits Need SVT hits to find Vertex Solution:Constrain in x-y plane to the beam Inflate error to error on beam size Comparable to  z from tag side Beam e-e- Beam-Spot Constrained Vertexing (BSCV) ++ Constrain in x-y to beam-spot B tag - Standard Method e+e+ y z K0sK0s Ks0Ks0 -- ++ ++ -- -- K0sK0s  tag  z ~ 180 m  rec  z ~ 50m For short lived particles

Searches for New Physics at BaBarH. Hadavand SUSY 0538 BsBs New particle in loop can change both the rate and phase SM: Photon approx left handed Other: Theories more L-R symmetric Sum of Exclusive modesInclusive, tagged recoil B Two Experimental Techniques 38 modes Kinematic constraints reduces background Lepton tag reduces bkg Reconstruct photon ( GeV) B+B+ B-B- X K , K s , etc B+B+ B-B- e or   XcXc XsXs

Searches for New Physics at BaBarH. Hadavand SUSY 0539 b  s  Preliminary Results A CP (b  s  +b  d  )  = ( ± ± ) Peak corresponding to K * resonance ( M(X s ) < 1.1 GeV/c 2 ) Semi-exclusive Inclusive tag A CP (b  s  )= ( ± ± ) “simpler” version of the analysis SM expectation A CP (b  s  +b  d  )  ~0 SM expectation: A CP (b  s  )  < 1% SM expectation ( Nucl. Phys B 631, 219 (2002)) : B (b  s   E   1.6 GeV)  = ( 3.57 ±0.30 )·10  PRL (2004) A total of 89M BB events are used B (E    1.6 GeV) = ( 3.38 ± 0.19 )·10  Y(4s) rest frame B rest frame

Searches for New Physics at BaBarH. Hadavand SUSY 0540 Another two penguin-dominated modes: B 0  ωK S, f 0 K S N sig = 153 ± 19 hep-ex/ (conf. paper) B 0  f 0 K S : yes, dominated by b → sss N sig = 92 ± 13 hep-ex/ (conf. paper) B 0  ωK S : dominated by b → sdd The possible tree contamination is relatively large.

Searches for New Physics at BaBarH. Hadavand SUSY 0541 B0  KSKSKS,KSπ0B 0  KS KS KS, KS π 0B0  KSKSKS,KSπ0B 0  KS KS KS, KS π 0 B 0  K S π 0 : tree pollution up to 20% B 0  K S K S K S : theoretically clean, η CP = +1 N sig = 88 ± 10 PRL (2005). N sig = 300 ± 23 hep-ex/ (submitted to PRD-RC) The B CP production point is constrained to the beamspot in ( x, y )

Searches for New Physics at BaBarH. Hadavand SUSY 0542 CP Violation in the B System  CPV through interference of decay amplitudes  CPV through interference between mixing and decay amplitudes

Searches for New Physics at BaBarH. Hadavand SUSY 0543 B 0  D* 0  Weak annihilation important for b  d  understanding: annihilation diagram in addition to rad penguin SM expectation M BB events Expected Background 9.4  1.7 Observed events13 B(B 0  D* 0  ) <2.5 x 10 90% hep-ex/ , submitted to PRL hep-ex/ , submitted to PRL