Negative meson capture in hydrogen. [Ionization cross sections, perturbed stationary state method]

Technical Report · Sat Jan 01 04:00:00 EST 1977

DOI:https://doi.org/10.2172/7322592· OSTI ID:7322592

Baird, T. J.

The processes of deexcitation and capture of negative mesons and hadrons in atomic hydrogen are investigated. Only slow collisions in which the projectile-atom relative velocity is less than one atomic unit are considered, and the motion of the incident particle is treated classically. For each classical trajectory the probability of ionizing the hydrogen atom is determined, together with the energy spectrum of the emitted electron. Ionization probabilities are calculated using the time-dependent formulation of the perturbed stationary state method. Exact two-center electronic wave functions are used for both bound and continuum states. The total ionization cross section and electron energy spectrum have been calculated for negative muons, kaons and antiprotons at incident relative velocities between 0.04 and 1.0 atomic units. The electron energy spectrum has a sharp peak for electron kinetic energies on the order of 10/sup -3/ Rydbergs. The ionization process thus favors the emission of very slow electrons. The cross section for ionization with capture of the incident particle was calculated for relative kinetic energies greater than 1.0 Rydberg. Since ionization was found to occur with the emission of electrons of nearly zero kinetic energy, the fraction of ionizing collisions which result in capture decreases very rapidly with projectile kinetic energy. The energy distributions of slowed down muons and hadrons were also computed. These distributions were used together with the capture cross section to determine the distribution of kinetic energies at which capture takes place. It was found that most captures occur for kinetic energies slightly less than 1.0 Rydbergs with relatively little capture at thermal energies. The captured particles therefore tend to go into very large and loosely found orbits with binding energies less than 0.1 Rydbergs.

• Research Organization: Los Alamos Scientific Lab., NM (USA)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 7322592
• Report Number(s): LA-6619-T
• Country of Publication: United States
• Language: English

Related Subjects

640303* -- Atomic
Molecular & Chemical Physics-- Positronium
Muonium
& Muonic & Mesic Atoms & Molecules
645206 -- High Energy Physics-- Particle Interactions & Properties-Theoretical-- Strong Interactions
Baryon No. = 1-- (-1987)
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
74 ATOMIC AND MOLECULAR PHYSICS
ANGULAR DISTRIBUTION
ANTIBARYONS
ANTIMATTER
ANTINUCLEI
ANTINUCLEONS
ANTIPARTICLES
ANTIPROTONS
ATOMS
BARYONS
BINDING ENERGY
BOSONS
BOUND STATE
CAPTURE
CROSS SECTIONS
CRYOGENIC FLUIDS
DE-EXCITATION
DISTRIBUTION
ELECTRONS
ELEMENTARY PARTICLES
ELEMENTS
EMISSION
ENERGY
ENERGY LEVELS
ENERGY SPECTRA
ENERGY-LEVEL TRANSITIONS
FERMIONS
FLUIDS
FUNCTIONS
FUNDAMENTAL CONSTANTS
HADRONIC ATOMS
HADRONS
HYDROGEN
IONIZATION
KAONIC ATOMS
KAONS
KAONS MINUS
LEPTONS
MATRIX ELEMENTS
MESIC ATOMS
MESONS
MUONIC ATOMS
MUONS
MUONS MINUS
NONMETALS
NUCLEI
PHASE SHIFT
PROBABILITY
PSEUDOSCALAR MESONS
RYDBERG CONSTANT
SPECTRA
STRANGE PARTICLES
TIME DEPENDENCE
TOTAL CROSS SECTIONS
TRAJECTORIES
WAVE FUNCTIONS