出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：I will review heavy baryon chiral perturbation theory for the nucleon delta degrees of freedom
and then examine the recent dynamical lattice calculations of the nucleon mass from the BMW,
ETM, JLQCD, LHP, MILC, NPLQCD, PACS-CS, QCDSF/UKQCD and RBC/UKQCD Collaborations.
Performing the chiral extrapolations of these results, one finds remarkable agreement
with the physical nucleon mass, from each lattice data set. However, a careful examination of
the lattice data and the resulting extrapolation functions reveals some unexpected results, serving
to highlight the significant challenges in performing chiral extrapolations of baryon quantities.
All the Nf = 2+1 dynamical results can be quantitatively described by theoretically unmotivated
fit function linear in the pion mass with mp 750–190 MeV. When extrapolated to the physical
point, the results are in striking agreement with the physical nucleon mass. I will argue that
knowledge of each lattice datum of the nucleon mass is required at the 1-2% level, including all
systematics, in order to conclusively determine if this is a bizarre conspiracy of lattice artifacts or
rather a mysterious phenomenon of QCD.
