We report a measurement of the inclusive D/D̄ production cross section in 800 GeV/ c proton-proton interactions. The experiment used the high resolution bubble chamber LEBC exposed to an 800 GeV/ c proton beam at the Fermilab MPS. We obtain σ( D/ D ̄ )=59 −15 +22 μ b (statistical errors), having analysed 25% of the total data sample. Comparison with 400 GeV/ c pp dat a obtained with LEBC at CERN shows a D/D̄ cross section increase by a factor of 1.7 −0.5 +0.7 . This is in good agreement with fusion model calculations.
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The inclusive branching fraction for B-meson decay into D0 mesons and the momentum spectrum of the D0's have been measured. 0.8±0.2±0.2 D0 per B decay was found. The shape of the spectrum suggests an interesting picture of B-meson decay.
NUMBER OF D0'S FROM UPSI(4S) REGION AFTER CORRECTION FOR THE CONTINUUM CONTRIBUTION.
Evidence is presented for a narrow meson resonance of mass 1970±5±5 MeV produced in continuum e+e− annihilations at s of 10.5 GeV, and decaying into a ϕ and a charged π.
CROSS SECTION OVER ALL F MOMENTA CALCULATED ASSUMING SPECTRUM BELOW 2.5 HAS SAME SHAPE AS D MESON PRODUCTION.
A measurement is presented of the inclusive production of charged D* and neutral D mesons from nonresonant e+e− annihilation in the energy region near the ϒ(4S) resonance. The momentum distribution shows a large contribution at high momenta as expected for heavy quark production. Comparison of the spectrum with several phenomenological models is made. The relative yields of the D* and D mesons indicate that the charm cross section is dominated by the D* contribution.
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The Mark II detector at SPEAR has been used to study D-meson production in e+e− annihilation at center-of-mass energies between 3.8 and 6.7 GeV. The neutral and charged D mesons are identified from their K∓π± and K∓π±π± decay modes. Measurements of RD and of the inclusive differential cross section s dσdz are presented. The quasi-two-body cross sections σDD¯, σD*D¯, and σD*D¯* are derived from an overall fit to the D recoil spectra. No evidence was found for the associated production of charmed mesons and charmed baryons.
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THE DIFFERENTIAL SCALING CROSS SECTION FOR NEUTRAL AND CHARGED D'S. DEFINITION OF Z IS 2*E(P=3)/SQRT(S).
A measurement is presented of inclusive charged D*(2010) production from nonresonant e+e− annihilation in the center-of-mass energy (W) range 10.2 GeV<W<10.6 GeV. Charged D* mesons are identified by the decays D*+→D0π+→K−π+π+ and the charge conjugate mode. It is found that 40 ± 7 ± 13% of the charm quarks from the process e+e−→cc¯ result in D* mesons with z>0.7 (z=2EW, where E is the D* energy).
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We present a study of the decay properties of charmed D mesons produced near the peak of the ψ′′(3770) resonance in e+e− annihilation. Branching fractions for nine Cabibbo-favored and three Cabibbo-suppressed decay modes are presented along with upper limits on one additional Cabibbo-favored and four additional Cabibbo-suppressed decay modes. A study of Kππ-decay-mode Dalitz plots reveals a large quasi-two-body pseudoscalar-vector component for the D0 decays and an apparent nonuniform population on the Dalitz plot for the D+ decay into K−π+π+. Using tagged events, we measure the charged-particle multiplicity and strange-particle content of D decays. A measurement of the D+ and D0 semileptonic decay fractions indicates that the D+ has a significantly longer lifetime than the D0.
INCLUSIVE CROSS SECTIONS UNCORRECTED FOR RADIATIVE EFFECTS.
Decay modes of the charmed mesons, D 0 and D + , are studied in e + e − annihilation data at 4.03 and 4.41 GeV c.m. energy. The products of cross section times branching ratio are measured for the K − π + , K − π + π + π − , K S π + π − and K − π + π + final states. Upper limits are established for the Cabibbo forbidden decays via π + π − , K + K − , K + K − π + , K + π + π − and π + π − π + . The K − π + π + π − final state is shown to be dominated by K − π + ρ 0 .
THESE PARTIAL CROSS SECTIONS ARE CONVERTED TO TOTAL D INCLUSIVE CROSS SECTIONS USING KNOWN BRANCHING RATIOS AND TABULATED IN M. PICCOLO ET AL., PL 86B, 220 (1979).
Inclusive momentum and energy spectra of neutral and charged D-mesons produced in e + e − annihilation at energies near 7 GeV are presented. The slope of the energy spectrum is similar to the charged pion spectrum at the same energy. The inclusive cross section σ(e + e − → D or D + anything) at 7 GeV is 4.8±1.3 nb.
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SCALING VARIABLE IS X(P=3,DEF=2*E(P=3)/SQRT(S)) > 0.54.
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