Summary of the seventh international symposium on meson-nucleon physics and the structure of the nucleon, MENU{close_quote}97

Journal Article · Fri May 01 04:00:00 EDT 1998 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.56071· OSTI ID:647276

Nefkens, B M ^[1]

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1. Dept. of Physics and Astronomy, UCLA, Los Angeles, California 90095 (United States)

MENU{close_quote}97 covered many stunning successes of chiral symmetry in intermediate energy reactions, especially of processes that involve pions. These successes include coupling constants, scattering lengths, threshold meson production, electric and magnetic polarizabilities of pions and nucleons, peripheral {ital NN} scattering, {pi}, {eta} and {ital K} decay rates and spectra. The {pi}N data bank at low energy, which in the past was notorious for the inconsistencies of different data sets, is shown to become consistent by deleting a modest number of previously accepted data sub-sets. There is a consensus on a better value for the pion-nucleon coupling constant, which has been a bone of contention earlier, namely, f{sub {pi}NN}{sup 2}/4{pi}=(75.4{plus_minus}0.4){times}10{sup {minus}3} in satisfactory agreement with the Goldberger-Treiman relation. The mass-spin/parity distribution of the experimentally established {pi}N resonances does not support the prediction of the harmonic oscillator type quark model. Some massive {Delta}{sup ++} resonances decay by {eta} emission to the {pi}{sup +}p{eta} final state. In contrast to this the decay of massive N{sup {asterisk}} states to {pi}{sup {minus}}p{eta} in small, less than 5{percent} of {Delta}{sup ++}{r_arrow}{pi}{sup +}p{eta}. A new {ital s}-wave {eta} decay has been identified, D{sub 33}(1700){r_arrow}P{sub 33}(1232)+{eta}. There is interesting new threshold data from CELSIUS on np{r_arrow}d{eta} as well as on pp{r_arrow}pp{eta} and np{r_arrow}np{eta}. {copyright} {ital 1998 American Institute of Physics.}

• Sponsoring Organization: USDOE
• OSTI ID: 647276
• Report Number(s): CONF-970842--
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 432; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
BARYON SPECTROSCOPY
CHIRAL SYMMETRY
COUPLING CONSTANTS
MASS SPECTRA
MESON SPECTROSCOPY
MESONS
NUCLEONS
PION-NUCLEON INTERACTIONS
QUANTUM CHROMODYNAMICS