1 Rare Bottom and Charm Decays at the Tevatron Dmitri Tsybychev (SUNY at Stony Brook) On behalf of CDF and D0 Collaborations Flavor Physics and CP-Violation Taiwan, May 8, 2008

FPCP 2008D. Tsybychev2 Rare Decays Electroweak symmetry breaking determines flavor structure CKM matrix, FCNC, CP-violation Rare decays are instrumental probes CKM matrix Sizeable deviations – sign of New Physics FCNC decays are forbidden at tree level in the SM Rates are highly suppressed in SM NP allows tree level processes, enhancement in loops Look for B 0 (s ) → μ + μ - B ± 0 (s) → h μ + μ - D 0 → μ + μ - D ± → π ± μ + μ -

B Physics at the Tevatron Flavor Creation q b q b Flavor Excitation q q b g b b Gluon Splitting g g g b - Mechanisms for b production in pp collisions at 1.96 TeV Total inelastic cross section at the Tevatron is ~1000 larger than b cross section Plethora of states accessible only at the Tevatron: B s, B c, Λ b, Ξ b, Σ b … Large backgrounds suppressed by triggers that target specific decays  (bb)

FPCP 2008D. Tsybychev4 Analysis Procedures Preselection of dimuon events Trigger Selection optimization Blind analysis Avoid biases Side-band background subtraction Normalization to resonant decays in similar final state Large, well-known BR in SM Efficiency normalization Significant signal – perform measurement Otherwise set limit for relevant process

FPCP 2008D. Tsybychev5 Discriminating Variables Isolation Flight length significance  impact parameter significance

FPCP 2008D. Tsybychev6 B 0 (s) → μ + μ - Br(B 0 s → μ + μ - ) = (3.42 ± 0.54 )x10 -9 Buras, PLB 566, 115 (2003) Br(B 0 d → μ + μ - ) = (1.00 ± 0.14 )x10 -9 suppressed by (V td /V ts ) 2 New Physics contribution: MSSM ~tan 6 (  for large  tan(  SUSY with R-parity violation (RPV) Z’ with off diagonal couplings

FPCP 2008D. Tsybychev7 B 0 (s) → μ + μ - Selection and Optimization Signal: MC Background: data mass sidebands Final selection Likelihood ratio (D0) Neural network (CDF) Check selection with control samples Misidentified muon Same sign muons

FPCP 2008D. Tsybychev8 B 0 (s) → μ + μ - Normalization Combinatorial backgrounds estimated from fit in mass sidebands and propagated to signal region BR normalized to B ± →J/ψK ±

FPCP 2008D. Tsybychev9 B 0 (s) → μ + μ - Results No excess over expected background observed B 0 s → μ + μ - B 0 d → μ + μ - CDF < 4.7x10 -8 < 1.5x10 -8 PRL 100, (2008) D0 < 7.3x10 -8 D0 Note 5344 New HFAG average < 4.7 x10 90% CL Most stringent to date!

FPCP 2008D. Tsybychev10 B 0 s → μ + μ - Prospects

FPCP 2008D. Tsybychev11 B ( ±, 0) (s) →h (±,0) μ + μ - Non resonant decays via box or penguin diagrams BaBar/Belle: B ± u →K  +  - PRD73, (2006) B 0 d →K *  +  - PRL96, (2006) Look for B 0 s →  +  - Prediction: BR( B 0 s →  +  - ) =1.6x10 -6 JPHYS G 29, 1103 (2003) NP Larger BR Modified invariant  mass Modified angular distributions Fourth Generation PRD 77, (2008)

FPCP 2008D. Tsybychev12 B ( ±, 0) (s) →h (±,0) μ + μ - Observations Remove resonant J/ψ,ψ(2S) by cutting on invariant  mass 44.7±  18.5±  7.5± 

FPCP 2008D. Tsybychev13 B ( ±, 0) (s) →h (±,0) μ + μ - Results BR(B 0 s →  +  - 90%CL CDF( hep-ex/ ) < 5.0x10 -6 (includes uncertainty on normalization channel) D0 ( PRD 74, (2006)) < 3.2x10 -6 PRD 74, (2006) B(±,0)(s)→h(±,0)l+l-

FPCP 2008D. Tsybychev14 D0→μ+μ-D0→μ+μ- B 0 s → μ + μ - vs D 0 → μ + μ - down quark sector vs up quark sector Short range contribution BR~ GIM suppressed Long range contribution BR ~ 4 x Burdman et al. hep-ph/ Significant enhancement possible in SUSY with R- parity violation Long range SM SUSY with R-parity violation

FPCP 2008D. Tsybychev15 D 0 → μ + μ - Analysis Events from two-track trigger Normalize to D 0 →  to cancel acceptance and trigger effects Background reduction by D* tag Muon ID efficiency from J/ψ → μμ data Muon mistag rate from D 0 →K  Background estimated from MC Dominant background from B → μμX Reduced by the impact parameter and lifetime significance cuts

FPCP 2008D. Tsybychev16 Results DetectorCMU-CMUCMU-CMXCMX-CMX Total Expected Background4.9 ± ± ± 0.5 Observed Events3 (p=0.3)0 (p=0.11)1 (p=0.7) BR(D 0 → μ+μ-) < 4.3 x at 90% CL λ 21k λ 22 k = 1.5 √ BR(D 0 → μ + μ - ) < 9.8 × CDF Note 9226

FPCP 2008D. Tsybychev17 D + (s) → π ± μ + μ - Orthogonal to B 0 s → μ + μ - Effects in up-quark sector factors of >1000 over SM not ruled out Long distance resonance production BR = 1.9x10 -6 Short distance continuum production Little Higgs models with new up sector vector quark Fajfer et al. hep-ph/ RPV in the up sector and not the down sector Burdman et al. hep-ph/

FPCP 2008D. Tsybychev18 Resonant D + (s) Decays Resonant production Selection of events with m( μμ ) in φ region N(D s + ) = 254 ± 36 N(D + ) = 115 ± 31 Statistical significance 8  for D s + and D +, 4.1  for D + First observation for D s First evidence for D + BR(D + →φ π + →μ + μ - π + ) = (1.8 ± 0.5 ± 0.6) x 10 -6

FPCP 2008D. Tsybychev19 Continuum D + (s) Decays Exclude resonant φ → μμ mass region 19 candidates in D + window Background expectation 25.8 ± 4.6 (p-value=0.14) Normalize to D + →φ π + BR( D + → μμ π + ) < 3.9 x 10 90% CL PRL 100, (2008)

FPCP 2008D. Tsybychev20 Summary B, D hadron decays provide a Sensitive Probe of EW Symmetry Breaking & Physics Beyond the SM Allow classes of models to be favored/ruled out Complementary to direct searches for new particles The CDF and DØ experiments are making major contributions to CKM measurements World’s best limits in B,D rare decays Complimentary to B factories Adding more data every day Significant reduction of New Physics parameter space Bounds on general flavor mixing Paving the way for LHC

21 BACKUP SLIDES

FPCP 2008D. Tsybychev22 The Tevatron Accelerator World’s highest energy collider Proton-antiproton synchrotron Experiments CDF and D Ø Run II ( ?)  s = 1.96 TeV Current peak luminosity L ~3 x cm -2 s -1 Expect up to L= ∫ L dt = 8 fb -1 integrated luminosity in Run II Large pp cross-section High collision rate 1.7 MHz

FPCP 2008D. Tsybychev23 Data Collected

FPCP 2008D. Tsybychev24 D 0 → μ + μ - Summary DetectorCMU-CMUCMU-CMXCMX-CMX Combinatorial Background0.040 ± ± ± B Decays Involving One Real Muon0.54 ± ± ± 0.02 B Decays Involving Two Real Muons3.8 ± ± ± 0.5 Total Expected Background4.9 ± ± ± 0.5 Observed Events301