Determination of {pi}{sup {+-}} meson polarizabilities from the {gamma}{gamma}{yields}{pi}{sup +}{pi}{sup -} process
- Lebedev Physical Institute, Leninsky Prospect 53, Moscow RU-119991 (Russian Federation)
A fit of the experimental data to the total cross section of the process {gamma}{gamma}{yields}{pi}{sup +}{pi}{sup -} in the energy region from threshold to 2500 MeV has been carried out using dispersion relations with subtractions for the invariant amplitudes, where the dipole and the quadrupole polarizabilities of the charged pion are free parameters. As a result, the sum and the difference of the electric and magnetic dipole and quadrupole polarizabilities of the charged pion have been found: ({alpha}{sub 1}+{beta}{sub 1}){sub {pi}{sup {+-}}}=(0.18{sub -0.02}{sup +0.11})x10{sup -4} fm{sup 3},({alpha}{sub 1}-{beta}{sub 1}){sub {pi}{sup {+-}}}=(13.0{sub -1.9}{sup +2.6})x10{sup -4} fm{sup 3},({alpha}{sub 2}+{beta}{sub 2}){sub {pi}{sup {+-}}}=(0.133{+-}0.015)x10{sup -4} fm{sup 5},({alpha}{sub 2}-{beta}{sub 2}){sub {pi}{sup {+-}}}=(25.0{sub -0.3}{sup +0.8})x10{sup -4} fm{sup 5}. These values agree with the dispersion sum rule predictions. The value found for the difference of the dipole polarizabilities is consistent with the results obtained from scattering of high energy {pi}{sup -} mesons off the Coulomb field of heavy nuclei [Yu. M. Antipov et al., Phys. Lett. B121, 445 (1983)] and from radiative {pi}{sup +} photoproduction from the proton at MAMI [J. Ahrens et al., Eur. Phys. J. A 23, 113 (2005)], whereas it is at variance with the recent calculations in the framework of chiral perturbation theory.
- OSTI ID:
- 20771384
- Journal Information:
- Physical Review. C, Nuclear Physics, Journal Name: Physical Review. C, Nuclear Physics Journal Issue: 3 Vol. 73; ISSN 0556-2813; ISSN PRVCAN
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
AMPLITUDES
CHIRALITY
COULOMB FIELD
DISPERSION RELATIONS
HEAVY NUCLEI
MAGNETIC DIPOLES
MEV RANGE
PERTURBATION THEORY
PHOTON-PHOTON INTERACTIONS
PHOTOPRODUCTION
PIONS MINUS
PIONS PLUS
POLARIZABILITY
PROTONS
QUADRUPOLES
SCATTERING
SUM RULES
TOTAL CROSS SECTIONS