D meson production in e/sup +/e/sup -/ annihilation

Thesis/Dissertation · Mon Jan 01 04:00:00 EST 1979

OSTI ID:5280173

Rapidis, P A

The production of D mesons in e/sup +/e/sup -/ 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 Rings facility. We observed a resonance in the total cross-section for hadron production in e/sup +/e/sup -/ annihilation at an energy just above the threshold for charm production. This resonance, which we name psi'', has a mass of 3772 +- 6 MeV/c/sup 2/, a total width of 28 +- 5 MeV/c/sup 2/, a partial width to electron pairs of 345 +- 85 eV/c/sup 2/, and decays almost exclusively into D anti D pairs. The psi'' 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 psi'' we have determined the masses of the D/sup 0/ and D/sup +/ mesons to be 1863.3 +- 0.9 MeV/c/sup 2/ and 1868.3 +- 0.9 MeV/c/sup 2/ respectively. We also determined the branching fractions for D/sup 0/ decay to K/sup -/..pi../sup +/, anti K/sup 0/..pi../sup +/..pi../sup -/ and K/sup -/..pi../sup +/..pi../sup -/..pi../sup +/ to be (2.2 +- 0.6)%, (4.0 +- 1.3)%, and (3.2 +- 1.1)% and the branching fractions for D/sup +/ decay to anti K/sup 0/..pi../sup +/ and K/sup -/..pi../sup +/..pi../sup +/ 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/sup 0/,s and 0.42 +- 0.12 K/sup +/,s. The rate for inclusive production of D mesons at center-of-mass energies above the psi'' 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 behavior suggests that the fragmentation function of the charmed quark into charmed mesons is a decreasing function of the scaling variable z = 2E/sub D//E/sub CM/.

• Research Organization: Stanford Univ., CA (USA)
• OSTI ID: 5280173
• Country of Publication: United States
• Language: English

Related Subjects

645101* -- High Energy Physics-- Particle Interactions & Properties-Experimental-- Electromagnetic Interactions & Properties
645102 -- High Energy Physics-- Particle Interactions & Properties-Experimental-- Weak Interactions & Properties
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ACCELERATORS
ANNIHILATION
BASIC INTERACTIONS
BOSONS
BRANCHING RATIO
CHARM PARTICLES
CHARMED MESON RESONANCES
COLLECTIVE ACCELERATORS
D RESONANCES
D-1865 RESONANCES
DATA
DECAY
ELECTROMAGNETIC INTERACTIONS
ELECTRON-POSITRON INTERACTIONS
ELECTRON-RING ACCELERATORS
ELEMENTARY PARTICLES
ENERGY RANGE
ENERGY SPECTRA
EXPERIMENTAL DATA
GEV RANGE
GEV RANGE 01-10
HADRONS
INCLUSIVE INTERACTIONS
INFORMATION
INTERACTIONS
KAONS
LEPTON-LEPTON INTERACTIONS
MASS
MESON RESONANCES
MESONS
NUMERICAL DATA
PARTICLE DECAY
PARTICLE INTERACTIONS
PARTICLE PRODUCTION
PARTICLE PROPERTIES
PARTICLE WIDTHS
PIONS
POSTULATED PARTICLES
PSEUDOSCALAR MESONS
PSI RESONANCES
PSI-3772 RESONANCES
QUARKS
RESONANCE PARTICLES
SPECTRA
STRANGE PARTICLES
VECTOR MESONS
WEAK PARTICLE DECAY