Chiral symmetry and the threshold {gamma}p {yields} {pi}{sup 0}p reaction

Technical Report · Mon Feb 28 23:00:00 EST 1994

DOI:https://doi.org/10.2172/10133458· OSTI ID:10133458

Lee, T S.H. ^[1]; Pearce, B C ^[2]

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1. Argonne National Lab., IL (United States)
2. TRIUMF, Vancouver, BC (Canada)

The threshold {gamma}p {yields} {pi}{sup 0}p reaction is investigated by using a chiral invariant {pi}N model in a unitary, gauge invariant, dynamical calculation based on a chiral Lagrangian. It is shown that the chiral invariant {pi}N final state interaction significantly suppresses the E{sub 0+} amplitude from the value {minus}2.4 {times} 10{sup {minus}3}m{sub {pi}}{sup {minus}1} predicted by the low energy theorem to {minus}0.66 {times} 10{sup {minus}3}m{sub {pi}}{sup {minus}1}. We discuss questions concerning the implications of the present results in interpreting the recent Mainz data and their multipole analysis. The experimental accuracy needed for investigating chiral symmetry breaking is illustrated.

• Research Organization: Argonne National Lab., IL (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States); Natural Sciences and Engineering Research Council of Canada, Ottawa, ON (Canada)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 10133458
• Report Number(s): ANL/PHY/PP--71811; ON: DE94008117
• Country of Publication: United States
• Language: English

Related Subjects

662120
662330
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
CHIRAL SYMMETRY
DIFFERENTIAL CROSS SECTIONS
FINAL-STATE INTERACTIONS
PHOTON AND CHARGED-LEPTON INTERACTIONS WITH HADRONS
PHOTON-PROTON INTERACTIONS
PHOTOPRODUCTION
PIONS NEUTRAL
SYMMETRY BREAKING
SYMMETRY
CONSERVATION LAWS
CURRENTS AND THEIR PROPERTIES