Momentum-transfer dependence of the cross section for e/sup +/e/sup -/ pair production by muons on nuclei

Journal Article · Thu Mar 01 04:00:00 EST 1979 · Sov. Phys. - JETP (Engl. Transl.); (United States)

OSTI ID:5787241

Nikishov, A I

For the case of e/sup +/e/sup -/ pair production by ultrarelativistic muons on nuclei, the dependence of the cross section and the energy spectrum of the pair on t=k/sup 2/, the square of the four-momentum transfer, is calculated. Asymptotic formulas for small and large values of the momentum transfer are examined. Qualitatively, we have dsigmaapprox.dt/t for tvery-much-less-thanm/sup 2/ and dsigmaapprox.dt/t/sup 2/ for t>>m/sup 2/. A decided asymmetry is found in the energy distribution between the components of the pair in the ''deep-inelastic'' region, where the energy k/sub 0/ of the pair is of the order of the square of the momentum transfer divided by the mass of the electron, k/sub 0/approx.k/sup 2//m; although the energy of the pair is large in this case, k/sub 0/>>2m, there is considerable probability that almost all of the energy is carried away by one particle of the pair, the energy of the other particle being only of the order of its mass. In accordance with the uncertainty relation, the distribution in momentum transfer gives a (qualitative) distribution in impact parameter. By treating the process as pair production by an external field, one can estimate probabilities for multiple pair production in collisions of fast nuclei with charges eZ and eZ'. In this way the ratio of the cross sections for production of two pairs and for a single pair is found to be sigma/sub 2//sigma/sub 1/approx. (..cap alpha../sup 2/ZZ'/..pi..)/sup 2/ln..gamma... Similarly, v/sub n/+1/sigma/sub n/approx. (..cap alpha../sup 2/ZZ'/..pi..)/sup 2/ln/sup 2/..gamma.., n> or =2, where ..gamma.. is the Lorentz factor of the incident nucleus.

• Research Organization: P. N. Lebedev Institute of Physics, Academy of Sciences of the USSR
• OSTI ID: 5787241
• Journal Information: Sov. Phys. - JETP (Engl. Transl.); (United States), Journal Name: Sov. Phys. - JETP (Engl. Transl.); (United States) Vol. 49:3; ISSN SPHJA
• Country of Publication: United States
• Language: English

Related Subjects

645202* -- High Energy Physics-- Particle Interactions & Properties-Theoretical-- Electromagnetic Interactions & Properties
653003 -- Nuclear Theory-- Nuclear Reactions & Scattering
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ASYMPTOTIC SOLUTIONS
CHARGED-PARTICLE REACTIONS
CROSS SECTIONS
DEEP INELASTIC SCATTERING
ELECTRON PAIRS
ENERGY RANGE
ENERGY SPECTRA
IMPACT PARAMETER
INELASTIC SCATTERING
INTERACTIONS
LEPTON REACTIONS
LEPTON-BARYON INTERACTIONS
LEPTON-HADRON INTERACTIONS
LEPTON-NUCLEON INTERACTIONS
MOMENTUM TRANSFER
MUON REACTIONS
NUCLEAR REACTIONS
PAIR PRODUCTION
PARTICLE INTERACTIONS
RELATIVISTIC RANGE
SCATTERING
SPECTRA