Fermilab E791 Collaboration
نویسندگان
چکیده
Using the large hadroproduced charm sample collected in experiment E791 at Fermilab, we have measured ratios of branching fractions for the two-body singlyCabibbo-suppressed charged decays of the D: Γ(D → KK) Γ(D → Kπ) = 0.109± 0.003± 0.003, Γ(D → ππ) Γ(D → Kπ) = 0.040 ± 0.002 ± 0.003, and Γ(D → KK) Γ(D → ππ) = 2.75 ± 0.15±0.16. We have looked for differences in the decay rates of D andD to the CP eigenstates KK and ππ, and have measured the CP asymmetry parameters ACP (K K) = −0.010± 0.049± 0.012 and ACP (π π) = −0.049± 0.078± 0.030, both consistent with zero. PACS: 11.30.Er; 13.25.Ft; 14.40.Lb The measured world average for the ratio of the branching fractions of the two-body singly-Cabibbo-suppressed (SCS) charged decays of the D meson is Γ(D → KK) Γ(D → ππ) = 2.86±0.28 [1]. Models including final state interactions [2,3], penguin diagrams [4], QCD sum rules [5], and non-perturbative algebraic approaches [6] have been proposed to explain the experimental value observed for this ratio. Precise measurements of this ratio can help to differentiate among models, and can also aid in our understanding of the Standard Model predictions forD–D mixing via long-range mechanisms, which require SU(3) symmetry-breaking to be non-zero [7,8]. ⋆ Submitted to Physics Letters B.
منابع مشابه
Decays from Fermilab E791 Representing the Fermilab E791 Collaboration
A new approach to the analysis of three body decays is presented. Model-independent results are obtained for the S-wave Kπ amplitude as a function of Kπ invariant mass. These are compared with results from K − π + elastic scattering, and the prediction of the Watson theorem , that the phase behavour be the same below Kη ′ threshold, is tested. Contributions from I = 1 2 and I = 3 2 are not reso...
متن کاملTotal Forward and Diierential Cross Sections of Neutral D Mesons Produced in 500 Gev/c ? {nucleon Interactions Fermilab E791 Collaboration
متن کامل
Recent Results from Fermilab Charm Experiment E791 Representing the Fermilab Experiment E791 Collaboration We Report the Results of Some Recent E791 Charm Analyses. They Include 1 a Search for Rare and Forbidden Decays, 2 Measurements of Form Factors For
E791 is a high statistics charm experiment that acquired data at Fermilab during the 1991-1992 xed-target run. The experiment combined a fast data acquisition system with an open trigger. Over 2 10 events were collected with the Tagged Photon Spectrometer [1] using a 500 GeV beam. There were ve target foils with 15 mm centerto-center separations: one 0.5 mm thick platinum foil followed by four ...
متن کاملReview of Recent Searches for Rare and Forbidden Dilepton Decays of Charmed Mesons
I briefly review the results of recent searches for flavor-changing neutral current and lepton-flavor and lepton-number violating decays of D, D s , and D 0 mesons (and their antiparticles) into modes containing muons and electrons. The primary focus is the results from Fermilab charm hadroproduction experiment E791. E791 examined 24 πll and Kll decay modes of D and D s and l l decay modes of D...
متن کامل-nucleon Interactions Representing the Fermilab E791 Collaboration
We present the Fermilab E791 measurement of baryon-antibaryon asymmetries in the production of Λ • , Ξ, Ω and Λc in 500 GeV/c π −-nucleon. Asymmetries have been measured as a function of xF and p 2 T over the range −0.12 < xF < 0.12 and p 2 T < 4 (GeV/c) 2 for hyperons and −0.1 < xF < 0.3 and p 2 T < 8 (GeV/c) 2 for the Λc baryons. We observe clear evidence of leading particle effects and a bas...
متن کامل