164 research outputs found
Continuous renal replacement therapy: should the cardiologist be able to manage it out of intensive care units?
Early invasive strategy and outcomes of non-ST-elevation acute coronary syndrome patients: is time really the major determinant?
Adherence to a Community-based Exercise Program Is a Strong Predictor of Improved Back Pain Status in Older Adults: An Observational Study.
Topics in Chiral Perturbation Theory
I consider some selected topics in chiral perturbation theory (CHPT). For the
meson sector, emphasis is put on processes involving pions in the isospin zero
S-wave which require multi-loop calculations. The advantages and shortcomings
of heavy baryon CHPT are discussed. Some recent results on the structure of the
baryons are also presented.Comment: 30 pp, TeX, Review talk, Third Workshop on High Energy Particle
Physics (WHEPP III), Madras, India, January 1994. 7 figures available upon
request. CRN--94/0
Critical Analysis of Baryon Masses and Sigma-Terms in Heavy Baryon Chiral Perturbation Theory
We present an analysis of the octet baryon masses and the and
--terms in the framework of heavy baryon chiral perturbation theory. At
next-to-leading order, , knowledge of the baryon masses and
allows to determine the three corresponding finite
low--energy constants and to predict the the two --terms
. We also include the spin-3/2 decuplet in the
effective theory. The presence of the non--vanishing energy scale due to the
octet--decuplet splitting shifts the average octet baryon mass by an infinite
amount and leads to infinite renormalizations of the low--energy constants. The
first observable effect of the decuplet intermediate states to the baryon
masses starts out at order . We argue that it is not sufficient to retain
only these but no other higher order terms to achieve a consistent description
of the three--flavor scalar sector of baryon CHPT. In addition, we critically
discuss an SU(2) result which allows to explain the large shift of via intermediate states.Comment: 18 pp, TeX, BUTP-93/05 and CRN-93-0
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