1,275 research outputs found
Cold Compressed Baryonic Matter with Hidden Local Symmetry and Holography
I describe a novel phase structure of cold dense baryonic matter predicted in
a hidden local symmetry approach anchored on gauge theory and in a holographic
dual approach based on the Sakai-Sugimoto model of string theory. This new
phase is populated with baryons with half-instanton quantum number in the
gravity sector which is dual to half-skyrmion in gauge sector in which chiral
symmetry is restored while light-quark hadrons are in the color-confined phase.
It is suggested that such a phase that aries at a density above that of normal
nuclear matter and below or at the chiral restoration point can have a drastic
influence on the properties of hadrons at high density, in particular on
short-distance interactions between nucleons, e.g., multi-body forces at short
distance and hadrons -- in particular kaons -- propagating in a dense medium.
Potentially important consequences on the structure of compact stars will be
predicted.Comment: 15 pages, to appear in proceedings of "Strong Coupling Gauge Theories
in LHC Era (SCGT09)," Nagoya, Japa
Hidden Local Symmetry and Infinite Tower of Vector Mesons for Baryons
In an effort to access dense baryonic matter relevant for compact stars in a
unified framework that handles both single baryon and multibaryon systems on
the same footing, we first address a holographic dual action for a single
baryon focusing on the role of the infinite tower of vector mesons
deconstructed from five dimensions. To leading order in 't Hooft coupling
, one has the Bogomol'nyi-Prasad-Sommerfield (BPS)
Skyrmion that results when the warping of the bulk background and the
Chern-Simons term in the Sakai-Sugimoto D4/D8- model are
ignored. The infinite tower was found by Sutcliffe to induce flow to a
conformal theory, i.e., the BPS. We compare this structure to that of the SS
model consisting of a 5D Yang-Mills action in warped space and the Chern-Simons
term in which higher vector mesons are integrated out while preserving hidden
local symmetry and valid to and in the chiral counting.
We point out the surprisingly important role of the meson that figures
in the Chern-Simons term that encodes chiral anomaly in the baryon structure
and that may be closely tied to short-range repulsion in nuclear interactions.Comment: 9 pages, REVTeX, to be published in Phys. Rev.
Chiral effective action with heavy quark symmetry
We derive an effective action combining chiral and heavy quark symmetry,
using approximate bosonization techniques of QCD. We explicitly show that the
heavy-quark limit is compatible with the large (number of color) limit in
the meson sector, and derive specific couplings between the light and heavy
mesons (, , ...) and their chiral partners. The relevance of this
effective action to solitons with heavy quarks describing heavy baryons is
discussed.Comment: 14 pages, SUNY-NTG-92/2
X-rays and Protostars in the Trifid Nebula
The Trifid Nebula is a young HII region recently rediscovered as a
"pre-Orion" star forming region, containing protostars undergoing violent mass
ejections visible in optical jets as seen in images from the Infrared Space
Observatory and the Hubble Space Telescope. We report the first X-ray
observations of the Trifid nebula using ROSAT and ASCA. The ROSAT image shows a
dozen X-ray sources, with the brightest X-ray source being the O7 star, HD
164492, which provides most of the ionization in the nebula. We also identify
85 T Tauri star and young, massive star candidates from near-infrared colors
using the JHKs color-color diagram from the Two Micron All Sky Survey (2MASS).
Ten X-ray sources have counterpart near-infrared sources. The 2MASS stars and
X-ray sources suggest there are potentially numerous protostars in the young
HII region of the Trifid. ASCA moderate resolution spectroscopy of the
brightest source shows hard emission up to 10 keV with a clearly detected Fe K
line. The best model fit is a two-temperature (T = 1.2x10^6 K and 39x10^6 K)
thermal model with additional warm absorbing media. The hotter component has an
unusually high temperature for either an O star or an HII region; a typical
Galactic HII region could not be the primary source for such hot temperature
plasma and the Fe XXV line emission. We suggest that the hotter component
originates in either the interaction of the wind with another object (a
companion star or a dense region of the nebula) or from flares from deeply
embedded young stars.Comment: Accepted in ApJ (Oct, 20 issue, 2001
Baryons with Two Heavy Quarks as Solitons
Using the chiral soliton model and heavy quark symmetry we study baryons
containing two heavy quarks. If there exists a stable (under strong
interactions) meson consisting of two heavy quarks and two light ones, then we
find that there always exists a state of this meson bound to a chiral soliton
and to a chiral anti-soliton, corresponding to a two heavy quark baryon and a
baryon containing two heavy anti-quarks and five light quarks, or a
``heptaquark".Comment: 7 pages and 2 postscript figures appended, LaTex, UCI-TR 94-3
Energy levels of the soliton--heavy-meson bound states
We investigate the bound states of heavy mesons with finite masses to a
classical soliton solution in the Skyrme model. For a given model Lagrangian we
solve the equations of motion exactly so that the heavy vector mesons are
treated on the same footing as the heavy pseudoscalar mesons. All the energy
levels of higher grand spin states as well as the ground state are given over a
wide range of the heavy meson masses. We also examine the validity of the
approximations used in the literatures. The recoil effect of finite mass
soliton is naively estimated.Comment: 24 pages, REVTeX v3.0, 6 figures are available upon request
Baryonic Response of Dense Holographic QCD
The response function of a homogeneous and dense hadronic system to a
time-dependent (baryon) vector potential is discussed for holographic dense QCD
(D4/D8 embedding) both in the confined and deconfined phases. Confined
holographic QCD is an uncompressible and static baryonic insulator at large N_c
and large \lambda, with a gapped vector spectrum and a massless pion.
Deconfined holographic QCD is a diffusive conductor with restored chiral
symmetry and a gapped transverse baryonic current. Similarly, dense D3/D7 is
diffusive for any non-zero temperature at large N_c and large \lambda. At zero
temperature dense D3/D7 exhibits a baryonic longitudinal visco-elastic mode
with a first sound speed \lambda/\sqrt{3} and a small width due to a shear
viscosity to baryon ratio \eta/n_B=\hbar/4. This mode is turned diffusive by
arbitrarily small temperatures, a hallmark of holography.Comment: V2: 47 pages, 7 figures, references added, typos correcte
Molecular and Ionic shocks in the Supernova Remnant 3C391
New observations of the supernova remnant 3C391 are in the H2 2.12 micron and
[Fe II] 1.64 micron narrow-band filters at the Palomar 200-inch telescope, and
in the 5-15 micron CVF on ISOCAM. Shocked H2 emission was detected from the
region 3C391:BML, where broad millimeter CO and CS lines had previously been
detected. A new H2 clump was confirmed to have broad CO emission, demonstrating
that the near-infrared H2 images can trace previously undetected molecular
shocks. The [Fe II] emission has a significantly different distribution, being
brightest in the bright radio bar, at the interface between the supernova
remnant and the giant molecular cloud, and following filaments in the radio
shell. The near-infrared [Fe II] and the mid-infrared 12-18 micron filter
images are the first images to reveal the radiative shell of 3C391. The
mid-infrared spectrum is dominated by bright ionic lines and H2 S(2) through
S(7). There are no aromatic hydrocarbons associated with the shocks, nor is
their any mid-infrared continuum, suggesting that macromolecules and very small
grains are destroyed. Comparing 3C391 to the better-studied IC443, both
remnants have molecular- and ionic-dominated regions; for 3C391, the
ionic-dominated region is the interface into the giant molecular cloud, showing
that the main bodies of giant molecular clouds contain significant regions with
densities 100 to 1000/cm^3 and a small filling factor with higher-density. The
molecular shocked region resolves into 16 clumps of H2 emission, with some
fainter diffuse emission but with no associated near-infrared continuum
sources. One of the clumps is coincident with a previously-detected OH 1720 MHz
maser. These clumps are interpreted as a cluster of pre-stellar, dense
molecular cores that are presently being shocked by the supernova blast wave
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