2,355 research outputs found
Implications of the Little Higgs Dark Matter and T-odd Fermions
We study the phenomenology of dark matter in the Littlest Higgs model with
T-parity after the discovery of Higgs boson. We analyze the relic abundance of
dark matter, focusing on the effects of coannihilaitons with T-odd fermions.
After determining the parameter space that predicts the correct relic abundance
measured by WMAP and Planck collaborations, we evaluate the elastic scattering
cross section between dark matter and nucleon. In comparison with experimental
results, we find that the lower mass of dark matter is constrained mildly by
LUX 2013 while the future XENON experiment has potential to explore most of the
parameter space for both T-odd lepton and T-odd quark coannihilation scenarios.
We also study the collider signatures of T-odd fermion pair production at the
LHC. Even though the production cross sections are large, it turns out very
challenging to search for these T-odd fermions directly at the collider because
the visible charged leptons or jets are very soft. Furthermore, we show that,
with an extra hard jet radiated out from the initial state, the T-odd quark
pair production can contribute significantly to mono-jet plus missing energy
search at the LHC
Density slope of the nuclear symmetry energy from the neutron skin thickness of heavy nuclei
Expressing explicitly the parameters of the standard Skyrme interaction in
terms of the macroscopic properties of asymmetric nuclear matter, we show in
the Skyrme-Hartree-Fock approach that unambiguous correlations exist between
observables of finite nuclei and nuclear matter properties. We find that
existing data on neutron skin thickness of Sn isotopes give an
important constraint on the symmetry energy and its
density slope at saturation density . Combining these
constraints with those from recent analyses of isospin diffusion and double
neutron/proton ratio in heavy-ion collisions at intermediate energies leads to
a more stringent limit on approximately independent of . The implication of these new constraints on the of
Pb as well as the core-crust transition density and pressure in neutron
stars is discussed.Comment: 18 pages, 9 figures, 1 table. Significantly expanded to include a
number of details and discussions. Title shortened. Accepted version to
appear in PR
Contributions of hyperon-hyperon scattering to subthreshold cascade production in heavy ion collisions
Using a gauged flavor SU(3)-invariant hadronic Lagrangian, we calculate the
cross sections for the strangeness-exchange reactions YY to N\Xi (Y=\Lambda,
\Sigma) in the Born approximation. These cross sections are then used in the
Relativistic Vlasov-Uehling-Uhlenbeck (RVUU) transport model to study \Xi
production in Ar+KCl collisions at incident energy of 1.76A GeV and impact
parameter b=3.5 fm. We find that including the contributions of hyperon-hyperon
scattering channels strongly enhances the yield of \Xi, leading to the
abundance ratio \Xi^{-}/(\Lambda+\Sigma^{0})=3.38E-3, which is essentially
consistent with the recently measured value of by the HADES collaboration at GSI.Comment: 8 pages, 5 figure
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