Charge symmetry breaking in the few nucleon system.

This report discusses two recent experiments that have produced new results in charge symmetry breaking, the fore-aft cross section asymmetry in n + p → d + π0 and the observation of the isospin-forbidden d + d → 4He + π0 reaction. These experiments are being analyzed using effective field theory that establishes a connection to the quark-level processes that generate all charge symmetry breaking: the down-up quark mass difference and electromagnetic effects among the quarks. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]