ONE-PION EXCHANGE AND THE OPTICAL MODEL

Journal Article · Thu Feb 01 00:00:00 EST 1962 · Nuclear Phys.

DOI:https://doi.org/10.1016/0029-5582(62)90210-9· OSTI ID:4801900

Bjorklund, F E; Lippmann, B A; Moravesik, M J

Starting with the two-body scattering amplitude, aa optical model potential for nucleon-nucleus scattering is calculated (I) using the one-pion exchange interaction alone, (2) modifying the s-wave part of this by using effective range theory, and (3) using the modified phase shift analysis for p-p scattering supplemented by charge independence and the Gammel-Thaler potential for the n-p scattering information. Part (1) works sufficiently well to suggest that the one-pion exchange force contributes more importantly to the nucleon- nucleus interaction than to the basic twonucleon scattering process. Part (2) produces an indifferent improvement on part (1). Part (3) represents the optical potential inferred from the most accurate twonucleon data presently available. This last evaluation of the optical potential is considered the most reliable to date since it includes, in a good approximation, all infinite number of the high angunlar momentum states of the two-nucleon amplitude, which play a very essential part in the optical potential. A systematic derivation of the optical model equations is included with special emphasis on the needs of the present calculation; in addition, criteria for the validity of the model are discussed. Allowance is made for the nuclear volume not being strictly proportional to the mass number (nuclear size effect) and for the inequality of the numbers of neutrons and protons in the nucleus (effect of neutron excess). For heavy nuclei, these effects influence results up to 25%. (auth)

• Research Organization: Univ. of California, Livermore, CA (United States)
• NSA Number: NSA-16-010832
• OSTI ID: 4801900
• Journal Information: Nuclear Phys., Vol. Vol: 29; Other Information: Orig. Receipt Date: 31-DEC-62
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

PHYSICS
ANGULAR MOMENTUM
CONFIGURATION
CROSS SECTIONS
DIFFERENTIAL EQUATIONS
EFFECTIVE RANGE THEORY
ELEMENTARY PARTICLES
ENERGY LEVELS
FIELD THEORY
GAMMEL-THALER POTENTIAL
INTERACTIONS
MASS
MOMENTUM
NEUTRONS
NUCLEAR MODELS
NUCLEI
NUCLEONS
NUMERICALS
OPE MODEL
OPTICAL MODEL
PARTICLE MODELS
PHASE SHIFT
PIONS
PROTONS
S-WAVE
SCATTERING