Recent results on D meson decays from BESMa HaiLong[For BES Collaboration]

Institute of High Energy Physics, Beijing China

CHARM06Beijing China2006-6-5

Outline Introduction Semileptonic decays Summary Inclusive decays Singly tagged D samples

BEPC colliderL ~ 11031 /cm2s @3.773GeVEcm~2-5 GeV

BESII detectorVC: xy = 100 m TOF: T = 180 ps counter: r= 3 cm MDC: xy = 220 m BSC: E/E= 22 % z = 5.5 cm dE/dx= 8.5 % = 7.9 mr B field: 0.4 T p/p=1.7%(1+p2) z = 3.1 cm

identification can be done by the Counter for the charged track with momentum of greater than 0.55 GeV/cdE/dxTOFdE/dx and TOF information

(3770) data sample~18 pb-1 data taken at 3.773 GeV~7 pb-1 data taken at the region from 3.768 GeV to 3.778 GeV~8 pb-1 data taken in the energy region from 3.665 to 3.878 GeVThe total Luminosity is about 33 pb-1

Motivation Isospin conservation impliesPDG04 BFThe called Longstanding puzzle in Charm decay!Is isospin conservation held in the D semileptonic decays? BESII [Phys. Lett. B608(2005)24]CLEO [Phys. Rev. Lett. 95(2005)181801]The puzzle has been solved!Branching fractionsCKM matrix elements and form factors

Form factor E691 0.450.11MARKIII 1.000.25(absolute)CLEO 0.510.180.06CLEO 0.600.090.07CLEO 0.650.090.10E687 0.590.100.13E687 0.620.070.09 CLEO 0.990.060.070.06FOCUS 0.5940.0430.030CLEO-c 0.630.030.02Early theories: 0.9-1.3Measurements:Recent theories:0.5-0.7MARKIII use a lower BF(D+K0e+ve )Shift in form factor prediction of early theoryBranching fractionsMotivation

serve as check on the sum of the branching fractions for the exclusive D decays provide information about the relative strength of Cabibbo-favored and Cabibbo-suppressed D decays.Up to now, PDG has not summarized the branching fractions for some inclusive decays of D mesonsMeasurements of branching fractions for the inclusive decays of D mesonsMotivation

Near DD-bar production threshold regione+e-DDK+tagD+D-e-e+DDK+tagSingly tagged D sampleAbsolute Measurements Semileptonic decays Inclusive decaysX+X0Throughout the talk, charge conjugation is impliedSingly tagged D samples

Singly tagged D- modes: (a)K+--;(b) K0 -; (c) K0 K-; (d) K+K--;(e) K0--+; (f) K+--0;(g) K0-0;(h) K+---+;(i) --+; (j) SumSingly tagged D0 modes: (a)K+-; (b) K+ --+; (c) K0 -+; (d) K+ -0ND-Tag=5321125160ND0Tag=7584198241Singly tagged D samplesMass[mKn]

Should be around zero due to the mass of the missing neutrino is zeroSemileptonic decaysUmiss=Emiss-pmiss|Umiss|

Umiss (GeV)Monte Carlo simulation|Umiss|

Candidates forCandidates forCandidates forThe yellow parts are from background eventsMass[mKn]

Branching fractionsPreliminary ResultsAn upper limit at 90% C.Lis set to be

Umiss (GeV)|Umiss|

Candidates forMass[mKn]Mass[K]

ResultsTend to support a smaller ratio Branching fractions(%) Ratio of partial widthAccepted by EPJC: hep-ex 0605103

No signal event is observed90%CLAccepted by EPJC: hep-ex 0604033Candidates forResults(%)(%)(%)

Inclusive DecaysMeasurements of branching fractions for the inclusive decays of D mesonse-DDK+tagSingly tagged D sampleX0e+

D0 signal regionCabibbo favored decayCabibbo suppressed decayMass[K-+]Mass[K+-]D0 sidebandD- signal regionD- sidebandD- signal regionD- sidebandD0 signal regionD0 sidebandCandidates for

ResultsCabibbo favored decay:Cabibbo suppressed decay:Phys. Lett. B625(2005)196

Candidates forD0 signal regionD0 sidebandD- signal regionD- sideband

Candidates forCabibbo favored decayCabibbo suppressed decayD0 signal regionD0 sidebandD- signal regionD- sidebandD- signal regionD- sidebandD0 signal regionD0 sideband

Preliminary results90%CL

BES measured branching fractions of D semileptonic decay The ratio ofSummary The ratio of BES search for and BES measured branching fractions for inclusive decaysThank You