17,066 research outputs found
The triangle-free graphs with rank 6
The rank of a graph G is defined to be the rank of its adjacency matrix A(G).
In this paper we characterize all connected triangle-free graphs with rank 6
Statefinder diagnostic for the modified polytropic Cardassian universe
We apply the Statefinder diagnostic to the Modified Polytropic Cardassian
Universe in this work. We find that the Statefinder diagnostic is quite
effective to distinguish Cardassian models from a series of other cosmological
models. The plane is used to classify the Modified Polytropic Cardassian
models into six cases. The evolutionary trajectories in the plane for the
cases with different and reveal different evolutionary properties
of the universe. In addition, we combine the observational data, the
Cosmic Microwave Background (CMB) data and the Baryonic Acoustic Oscillation
(BAO) data to make a joint analysis. We find that \textbf{Case 2} can be
excluded at the 68.3% confidence level and any case is consistent with the
observations at the 95.4% confidence level.Comment: Comments: Final version for publication in Physical Review D [minor
revision to match the appear version] Journal-ref: Physical Review D 75,
083515 (2007
Conical Defects, Black Holes and Higher Spin (Super-)Symmetry
We study the (super-)symmetries of classical solutions in the higher spin
(super-)gravity in AdS. We show that the symmetries of the solutions are
encoded in the holonomy around the spatial circle. When the spatial holonomies
of the solutions are trivial, they preserve maximal symmetries of the theory,
and are actually the smooth conical defects. We find all the smooth conical
defects in the , as well as in
and Chern-Simons gravity theories. In the bosonic higher spin
cases, there are one-to-one correspondences between the smooth conical defects
and the highest weight representations of Lie group. Furthermore we investigate
the higher spin black holes in and higher spin
(super-)gravity and find that they are only partially symmetric. In general,
the black holes break all the supersymmetries, but in some cases they preserve
part of the supersymmetries.Comment: 48 pages; more clarifications on conical defects in supersymmetric
cas
LHC Phenomenology of Type II Seesaw: Nondegenerate Case
In this paper, we thoroughly investigate the LHC phenomenology of the type II
seesaw mechanism for neutrino masses in the nondegenerate case where the
triplet scalars of various charge () have
different masses. Compared with the degenerate case, the cascade decays of
scalars lead to many new, interesting signal channels. In the positive scenario
where , the four-lepton signal is still
the most promising discovery channel for the doubly-charged scalars
. The five-lepton signal is crucial to probe the mass spectrum of
the scalars, for which, for example, a reach at 14 TeV LHC for
with requires an integrated
luminosity of 76/fb. And the six-lepton signal can be used to probe the neutral
scalars , which are usually hard to detect in the degenerate case. In
the negative scenario where , the
detection of is more challenging, when the cascade decay
is dominant. The most important channel is the
associated production in the final state
, which requires a luminosity of 109/fb
for a discovery, while the final state
is less promising. Moreover, the
associated production can give same signals as the standard model
Higgs pair production. With a much larger cross section, the
production in the final state could reach
significance at 14 TeV LHC with a luminosity of 300/fb. In summary, with an
integrated luminosity of order 500/fb, the triplet scalars can be fully
reconstructed at 14 TeV LHC in the negative scenario.Comment: 41 pages, 20 figures, 7 tables. Version 2 accepted by PRD. 41 pages,
18 figures. Main changes are, (1) rewording in secs III and IV, removing 2
figs and quoting ref [34]; (2) a paragraph added before eq (10) to clarify
constraints from electroweak precision data; (3) a paper added to ref [11].
No changes in result
- …