2,900 research outputs found
Conformal anomaly and the vector coupling in dense matter
We construct an effective chiral Lagrangian for hadrons implemented by the
conformal invariance and discuss the properties of nuclear matter at high
density. The model is formulated based on two alternative assignment, "naive"
and mirror, of chirality to the nucleons. It is shown that taking the dilaton
limit, in which the mended symmetry of Weinberg is manifest, the vector-meson
Yukawa coupling becomes suppressed and the symmetry energy becomes softer as
one approaches the chiral phase transition. This leads to softer equations of
state (EoS) and could accommodate the EoS without any exotica consistent with
the recent measurement of a neutron star.Comment: v2:10 pages, 2 figures, typos corrected, a rough estimate of m0 adde
Chiral Symmetry In Nuclear Physics
How chiral symmetry -- which is a basic ingredient of quantum chromodynamics (QCD) for light-quark hadrons -- enters and plays an eminent role in nuclear physics is discussed. This is done in two steps. In the first step, I introduce the notion of the Cheshire Cat Principle which describes how a strong-interaction phenomenon can be described in various different languages. In the second step, I treat two cases of widely different density regimes. The first case deals with formulating nuclear physics of {\it dilute} nuclear systems with a focus on both bound and scattering processes in two-nucleon systems in terms of effective field theories (EFT), e.g., in the framework of chiral perturbation theory. The second case requires formulating effective field theories for {\it dense} hadronic matter such as heavy nuclei and nuclear matter under normal as well as extreme conditions expected to be encountered in compact stars and in heavy-ion collisions at relativistic energy. The first case is rigorously formulated but the second relies on several assumptions that appear to be reasonable but need ultimately to be justified. The Cheshire Cat Principle is proposed to play an essential role in lending support to the latter development
Effective field theory of the deuteron with dibaryon field
Pionless effective field theory with dibaryon fields is reexamined for
observables involving the deuteron. The electromagnetic form factors of the
deuteron and the total cross sections of radiative neutron capture on the
proton, , are calculated. The low energy constants of
vector(photon)-dibaryon-dibaryon vertices in the effective lagrangian are fixed
primarily by the one-body vector(photon)-nucleon-nucleon interactions. This
scheme for fixing the values of the low energy constants satisfactorily
reproduces the results of the effective range theory. We also show that, by
including higher order corrections, one can obtain results that are close to
those of Argonne v18 potential model.Comment: 25 pages and 11 figures; 16 references added, Figure 6 and 7
replotted, text revised a lot. To be published in Phys. Rev.
Analysis of MMIC arrays for use in the ACTS Aero Experiment
The Aero Experiment is designed to demonstrate communication from an aircraft to an Earth terminal via the ACTS. This paper describes the link budget and antenna requirements for a 4.8 kbps full-duplex voice link at Ka-Band frequencies. Three arrays, one transmit array developed by TI and two receive arrays developed by GE and Boeing, were analyzed. The predicted performance characteristics of these arrays are presented and discussed in the paper
The Solar pp and hep Processes in Effective Field Theory
The strategy of modern effective field theory is exploited to pin down
accurately the flux factors for the and processes in the Sun.
The technique used is to combine the high accuracy established in few-nucleon
systems of the "standard nuclear physics approach" (SNPA) and the systematic
power counting of chiral perturbation theory (ChPT) into a consistent effective
field theory framework. Using highly accurate wave functions obtained in the
SNPA and working to \nlo3 in the chiral counting for the current, we make
totally parameter-free and error-controlled predictions for the and
processes in the Sun.Comment: 5 pages, aipproc macros are included. Talk given at International
Nuclear Physics Conference 2001, Berkeley, California, July 30 - August 3,
200
- …