5,718 research outputs found
Aspects of Nucleon Chiral Perturbation Theory
I review recent progress made in the calculation of nucleon properties in the
framework of heavy baryon CHPT. Topics include: Compton scattering,
scattering, the anatomy of a low-energy constant and the induced pseudoscalar
form factor.Comment: plain TeX (macro included), 12pp, lecture delivered at the workshop
on "Chiral Dynamics: Theory and Experiments", MIT, July 25-29, 199
Lattice Theories with Nonlinearly Realized Chiral Symmetry
We present the lattice formulation of effective Lagrangians in which chiral
symmetry is realized nonlinearly on the fermion fields. In this framework both
the Wilson term removing unphysical doubler fermions and the fermion mass term
do not break chiral symmetry. Our lattice formulation allows us to address
non-perturbative questions in effective theories of baryons interacting with
pions and in models involving constitutent quarks interacting with pions and
gluons. With the presented methods, a system containing a non-zero density of
static baryons interacting with pions can be studied on the lattice without
encountering a complex action problem. This might lead to new insights into the
phase diagram of strongly interacting matter at non-zero chemical potential.Comment: 3 pages, Lattice2003(chiral
Nucleon-Deuteron Scattering from an Effective Field Theory
We use an effective field theory to compute low-energy nucleon-deuteron
scattering. We obtain the quartet scattering length using low energy constants
entirely determined from low-energy nucleon-nucleon scattering. We find
fm, to be compared to fm.Comment: 8 pages, Latex, epsfig, figures include
Nonlocality of the NN interaction in an effective field theory
We investigate low energy nucleon dynamics in the effective field theory
(EFT) of nuclear forces. In leading order of the two-nucleon EFT we show that
nucleon dynamics is governed by the generalized dynamical equation with a
nonlocal-in-time interaction operator. This equation is shown to open new
possibilities for applying the EFT approach to the description of low energy
nucleon dynamics.Comment: 13 pages, 4 figures, REVTeX
Palatini Variational Principle for -Dimensional Dilaton Gravity
We consider a Palatini variation on a general -Dimensional second order,
torsion-free dilaton gravity action and determine the resulting equations of
motion. Consistency is checked by considering the restraint imposed due to
invariance of the matter action under simple coordinate transformations, and
the special case of N=2 is examined. We also examine a sub-class of theories
whereby a Palatini variation dynamically coincides with that of the "ordinary"
Hilbert variational principle; in particular we examine a generalized
Brans-Dicke theory and the associated role of conformal transformations.Comment: 16 pages, LaTe
Renormalization of One-Pion Exchange and Power Counting
The renormalization of the chiral nuclear interactions is studied. In leading
order, the cutoff dependence is related to the singular tensor interaction of
the one-pion exchange potential. In S waves and in higher partial waves where
the tensor force is repulsive this cutoff dependence can be absorbed by
counterterms expected at that order. In the other partial waves additional
contact interactions are necessary. The implications of this finding for the
effective-field-theory program in nuclear physics are discussed.Comment: 19 pages, 18 figure
Charge-Independence Breaking in the Two-Pion-Exchange Nucleon-Nucleon Force
Charge-independence breaking due to the pion-mass difference in the (chiral)
two-pion-exchange nucleon-nucleon force is investigated. A general argument
based on symmetries is presented that relates the charge-symmetric part of that
force to the proton-proton case. The static potential linear in that mass
difference is worked out as an explicit example by means of Feynman diagrams,
and this confirms the general argument.Comment: 10 pages, latex, 1 figure -- epsfig.sty required -- To appear in
Phys. Rev.
Canonical Quantization Inside the Schwarzschild Black Hole
We propose a scheme for quantizing a scalar field over the Schwarzschild
manifold including the interior of the horizon. On the exterior, the timelike
Killing vector and on the horizon the isometry corresponding to restricted
Lorentz boosts can be used to enforce the spectral condition. For the interior
we appeal to the need for CPT invariance to construct an explicitly positive
definite operator which allows identification of positive and negative
frequencies. This operator is the translation operator corresponding to the
inexorable propagation to smaller radii as expected from the classical metric.
We also propose an expression for the propagator in the interior and express it
as a mode sum.Comment: 8 pages, LaTex. Title altered. One reference added. A few typos esp.
eq.(7),(38) corrected. To appear in Class.Q.Gra
- …