FIZIKA B 14 (2005)  2, 217 - 234

LONG DISTANCE EFFECTS AND STRANGENESS IN THE NUCLEON

JOHN F. DONOGHUE^a, BARRY R. HOLSTEIN^a, TOBIAS HUBER^a,b,c and ANDREAS ROSS^a,b

^aDepartment of Physics-LGRT, University of Massachusetts, Amherst, MA 01003
^bInstitut für Theoretische Teilchenphysik, Universität Karlsruhe, Karlsruhe, Germany
^cInstitut für Theoretische Physik, Universität Zürich, Zürich, Switzerland

Dedicated to the memory of Professor Dubravko Tadić

Received 9 December 2004;  Accepted 20 June 2005
Online 2 December 2005

We discuss the calculation of the strange magnetic radius of the proton in chiral perturbation theory. In particular, we investigate the low-energy component of the loop integrals involving kaons. We separate the chiral calculation into a low-energy part and a high-energy component through use of a momentum space separation scale. This separation shows that most of the chiral calculation comes from high energies where the effective field theory treatment is not valid. The resulting low-energy prediction is in better agreement with dispersive treatments. Finally, we briefly discuss magnetic moments and show how our techniques can help resolve an old puzzle in understanding the magnetic moments of the proton and S⁺.

PACS numbers: 13.40.Em, 12.39.-x
UDC 539.125

Keywords: magnetic moments, proton, S⁺, strange magnetic radius, chiral perturbation theory

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