1,415 research outputs found
Baryons and Mesons with Beauty
Recent experimental findings of several mesons and baryons with "beauty" and
"charm" as flavors remind us of the days when strangeness was discovered, and
how its inclusion led to SU(3)-flavor symmetry with enormous success in the
classification of the "proliferated" states into SU(3) multiplets. One of the
key elements was the successful application of the first order perturbation in
symmetry breaking, albeit what then appeared to be huge mass differences, and
the prediction of new states that were confirmed by experiments. In this note,
we venture into the past and, applying the same techniques, predict some new
"beauty-" and "charm-" flavored hadrons. If these new states are confirmed
experimentally, it may provide a useful phenomenological model for classifying
numerous states that are found to be in the PDG data and could invite further
theoretical challenges towards our understanding of symmetry breaking.Comment: 9 pages, 5 figures, plain Late
Observed galaxy power spectrum in cubic Galileon model
In this paper, we study the effects of general relativistic corrections on
the observed galaxy power spectrum in thawing class of cubic Galileon model
with linear potential that preserves the shift symmetry. In this scenario, the
observed galaxy power spectrum differs from the standard matter power spectrum
mainly due to redshift space distortion (RSD) factor and relativistic effects.
The RSD term enhances the matter power spectrum both at larger and smaller
scales whereas the relativistic terms further enhance the matter power spectrum
only at larger scales. In comparison with CDM, the observed galaxy
power spectrum is always suppressed at large scales in this scenario although
this suppression is always small compared to the canonical quintessence
scenario.Comment: 14 pages, LaTeX style, 7 figures, Comments are welcom
Clash of symmetries on the brane
If our 3+1-dimensional universe is a brane or domain wall embedded in a
higher dimensional space, then a phenomenon we term the ``clash of symmetries''
provides a new method of breaking some continuous symmetries. A global
symmetry is spontaneously broken
to , where the continuous subgroup
can be embedded in several different ways in the parent group
, and . A certain
class of topological domain wall solutions connect two vacua that are invariant
under {\it differently embedded} subgroups. There is then
enhanced symmetry breakdown to the intersection of these two subgroups on the
domain wall. This is the ``clash''. In the brane limit, we obtain a
configuration with symmetries in the bulk but the smaller
intersection symmetry on the brane itself. We illustrate this idea using a
permutation symmetric three-Higgs-triplet toy model exploiting the distinct
, and spin U(2) subgroups of U(3). The three disconnected portions
of the vacuum manifold can be treated symmetrically through the construction of
a three-fold planar domain wall junction configuration, with our universe at
the nexus. A possible connection with is discussed.Comment: 30 pages, 9 embedded figure
The clash of symmetries in a Randall-Sundrum-like spacetime
We present a toy model that exhibits clash-of-symmetries style Higgs field
kink configurations in a Randall-Sundrum-like spacetime. The model has two
complex scalar fields Phi_{1,2}, with a sextic potential obeying global
U(1)xU(1) and discrete Phi_1 Phi_2 interchange symmetries. The scalar
fields are coupled to 4+1 dimensional gravity endowed with a bulk cosmological
constant. We show that the coupled Einstein-Higgs field equations have an
interesting analytic solution provided the sextic potential adopts a particular
form. The 4+1 metric is shown to be that of a smoothed-out Randall-Sundrum type
of spacetime. The thin-brane Randall-Sundrum limit, whereby the Higgs field
kinks become step functions, is carefully defined in terms of the fundamental
parameters in the action. The ``clash of symmetries'' feature, defined in
previous papers, is manifested here through the fact that both of the U(1)
symmetries are spontaneously broken at all non-asymptotic points in the extra
dimension . One of the U(1)'s is asymptotically restored as w --> -infinity,
with the other U(1) restored as w --> +infinity. The spontaneously broken
discrete symmetry ensures topological stability. In the gauged version of this
model we find new flat-space solutions, but in the warped metric case we have
been unable to find any solutions with nonzero gauge fields.Comment: 15 pages, 5 figures; minor changes including added references and an
updated figure; to appear in Phys Rev
Quintessential inflation with canonical and noncanonical scalar fields and Planck 2015 results
We investigate two classes of models of quintessential inflation, based upon
canonical as well as noncanonical scalar fields. In particular, introducing
potentials steeper than the standard exponential, we construct models that can
give rise to a successful inflationary phase, with signatures consistent with
Planck 2015 results. Additionally, using nonminimal coupling of the scalar
field with massive neutrino matter, we obtain the standard thermal history of
the Universe, with late-time cosmic acceleration as the last stage of
evolution. In both cases, inflation and late-time acceleration are connected by
a tracker solution.Comment: 13 pages, 18 figures, minor clarifications added and refs updated, to
appear in PR
The Inter-Mammary Sticky Roll: A Novel Technique for Securing a Doppler Ultrasonic Probe to the Precordium for Venous Air Embolism Detection.
Venous air embolism is a devastating and potentially life-threatening complication that can occur during neurosurgical procedures. We report the development and use of the "inter-mammary sticky roll," a technique to reliably secure a precordial Doppler ultrasonic probe to the chest wall during neurosurgical cases that require lateral decubitus positioning. We have found that this noninvasive technique is safe, and effectively facilitates a constant Doppler signal with no additional risk to the patient
Light-Heavy Symmetry: Geometric Mass Hierarchy for Three Families
The Universal Seesaw pattern coupled with a LightHeavy
symmetry principle leads to the Diophantine equation , where and distinct. Its unique non-trivial
solution gives rise to the geometric mass hierarchy ,
, for fermion families. This is realized in
a model where the hybrid (yet UpDown symmetric) quark mass
relations play a
crucial role in expressing the CKM mixings in terms of simple mass ratios,
notably .Comment: 12 pages, no figures, Revtex fil
SU(5) grand unification on a domain-wall brane from an E_6-invariant action
An SU(5) grand unification scheme for effective 3+1-dimensional fields
dynamically localised on a domain-wall brane is constructed. This is achieved
through the confluence of the clash-of-symmetries mechanism for symmetry
breaking through domain-wall formation, and the Dvali-Shifman gauge-boson
localisation idea. It requires an E_6 gauge-invariant action, yielding a
domain-wall solution that has E_6 broken to differently embedded SO(10) x U(1)
subgroups in the two bulk regions on opposite sides of the wall. On the wall
itself, the unbroken symmetry is the intersection of the two bulk subgroups,
and contains SU(5). A 4+1-dimensional fermion family in the 27 of E_6 gives
rise to localised left-handed zero-modes in the 5^* + 10 + 1 + 1 representation
of SU(5). The remaining ten fermion components of the 27 are delocalised exotic
states, not appearing in the effective 3+1-dimensional theory on the
domain-wall brane. The scheme is compatible with the type-2 Randall-Sundrum
mechanism for graviton localisation; the single extra dimension is infinite.Comment: 21 pages, 9 figures. Minor changes to text and references. To appear
in Phys. Rev.
- …
