D Meson Production in e⁺e^- annihilation [Thesis; 3. 7 to 7. 0 GeV, total cross section, branching ratio]

Technical Report · Fri Jun 01 04:00:00 EDT 1979

DOI:https://doi.org/10.2172/6128133· OSTI ID:6128133

Rapidis, Petros-Afentoulis A ^[1]

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1. SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)

The production of D mesons in e⁺e^- annihilation for the center-of-mass energy range 3.7 to 7.0 GeV has been studied with the MARK I magnetic detector at the Stanford Positron Electron Accelerating Ring facility. We observed a resonance in the total cross-section for hadron production in e⁺e^- annihilation at an energy just above the threshold for charm production. This resonance, which we name ψ", has a mass of 3772 ± 6 MeV/c², a partial width to electron pairs of 345 ± 85 eV/c², and decays almost exclusively into $$D\overline{D}$$ pairs. The ψ" provides a rich source of background-free and kinematically well defined D mesons for study. From the study of D mesons produced in the decay of the ψ" we have determined the masses of the D^o and D⁺ mesons to be 1863.3 ± 0.9 MeV/c² and 1868.3 ± 0.9 MeV/c² respectively. we also determined the branching fraction for D^o to K^-π⁺, K^-oπ⁺π^- and K^-π⁺π^-π⁺ to be (2.2 ± 0.6)%, (4.0 ± 1.3)%, and (3.2 ± 1.1)% and the branching fractions for D⁺ decay to K^-oπ⁺ and K^-π⁺π⁺ to be (1.5 ± 0.6)% and (3.9 ± 1.0)%. The average number of kaons per D decay was found to be 0.52 ± 0.14 K^o's and 0.42 ± 0.12 K⁺'s. The rate for inclusive production of D mesons at center-of-mass energies above the ψ" has been measured; we find that it can account for most, if not all, of the observed increase in the total hadronic cross-section for center-of-mass energies above 4 GeV. The inclusive momentum and energy spectra for D's have been measured at the highest available center-of-mass energy (7 GeV). The energy spectra are rapidly decreasing functions of energy with a slope similar to the slope of the charged pion spectrum at the same center-of-mass energy. This behaviour suggests that the fragmentation function of the charmed quark into charmed mesons is a decreasing function of the scaling variable z = 2E_D/E_CM.

• Research Organization: SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: EY-76-C-03-0515
• OSTI ID: 6128133
• Report Number(s): SLAC--220; SLAC-R--220
• Country of Publication: United States
• Language: English

Related Subjects

645101 -- High Energy Physics-- Particle Interactions & Properties-Experimental-- Electromagnetic Interactions & Properties
645104* -- High Energy Physics-- Particle Interactions & Properties-Experimental-- Strong Meson-Induced Interactions-- (-1987)
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANNIHILATION
BASIC INTERACTIONS
BOSONS
BRANCHING RATIO
CHARM PARTICLES
CHARMED MESON RESONANCES
CROSS SECTIONS
D RESONANCES
D-1865 RESONANCES
DATA
DATA FORMS
DECAY
ELECTROMAGNETIC INTERACTIONS
ELECTRON-POSITRON INTERACTIONS
ELEMENTARY PARTICLES
EMISSION
ENERGY RANGE
ENERGY SPECTRA
EXPERIMENTAL DATA
GEV RANGE
GEV RANGE 01-10
GRAPHS
HADRONIC PARTICLE DECAY
HADRONS
INCLUSIVE INTERACTIONS
INFORMATION
INTERACTIONS
INVARIANCE PRINCIPLES
ISOLATED VALUES
KAONS
LEPTON-LEPTON INTERACTIONS
LEPTONIC DECAY
LINEAR MOMENTUM
MASS
MASS DIFFERENCE
MASS SPECTRA
MESON RESONANCES
MESONS
NUMERICAL DATA
PARTICLE DECAY
PARTICLE INTERACTIONS
PARTICLE PRODUCTION
PARTICLE PROPERTIES
PARTICLE WIDTHS
POSTULATED PARTICLES
PSEUDOSCALAR MESONS
PSI RESONANCES
PSI-3772 RESONANCES
QUARKS
RESONANCE PARTICLES
SCALE INVARIANCE
SPECTRA
STRANGE PARTICLES
TOTAL CROSS SECTIONS
VECTOR MESONS
WEAK INTERACTIONS
WEAK PARTICLE DECAY