1,605 research outputs found
Determination of Dark Matter Halo Mass from Dynamics of Satellite Galaxies
We show that the mass of a dark matter halo can be inferred from the
dynamical status of its satellite galaxies. Using 9 dark-matter simulations of
halos like the Milky Way (MW), we find that the present-day substructures in
each halo follow a characteristic distribution in the phase space of orbital
binding energy and angular momentum, and that this distribution is similar from
halo to halo but has an intrinsic dependence on the halo formation history. We
construct this distribution directly from the simulations for a specific halo
and extend the result to halos of similar formation history but different
masses by scaling. The mass of an observed halo can then be estimated by
maximizing the likelihood in comparing the measured kinematic parameters of its
satellite galaxies with these distributions. We test the validity and accuracy
of this method with mock samples taken from the simulations. Using the
positions, radial velocities, and proper motions of 9 tracers and assuming
observational uncertainties comparable to those of MW satellite galaxies, we
find that the halo mass can be recovered to within 40%. The accuracy can
be improved to within 25% if 30 tracers are used. However, the dependence
of the phase-space distribution on the halo formation history sets a minimum
uncertainty of 20% that cannot be reduced by using more tracers. We
believe that this minimum uncertainty also applies to any mass determination
for a halo when the phase space information of other kinematic tracers is used.Comment: Accepted for publication in ApJ, 18 pages, 13 figure
The naturalness in the BLMSSM and B-LSSM
In order to interpret the Higgs mass and its decays more naturally, we hope
to intrude the BLMSSM and B-LSSM. In the both models, the right-handed neutrino
superfields are introduced to better explain the neutrino mass problems. In
addition, there are other superfields considered to make these models more
natural than MSSM. In this paper, the method of analyses will be
adopted in the BLMSSM and B-LSSM to calculate the Higgs mass, Higgs decays and
muon . With the fine-tuning in the region and ,
we can obtain the reasonable theoretical values that are in accordance with the
experimental results respectively in the BLMSSM and B-LSSM. Meanwhile, the
best-fitted benchmark points in the BLMSSM and B-LSSM will be acquired at
minimal and ,
respectively
The order analysis for the two loop corrections to lepton MDM
The experimental data of the magnetic dipole moment(MDM) of lepton(,
) is very exact. The deviation between the experimental data and the
standard model prediction maybe come from new physics contribution.
In the supersymmetric models, there are very many two loop diagrams
contributing to the lepton MDM. In supersymmetric models, we suppose two mass
scales and with for supersymmetric particles.
Squarks belong to and the other supersymmetric particles belong to
. We analyze the order of the contributions from the two loop diagrams. The
two loop triangle diagrams corresponding to the two loop self-energy diagram
satisfy Ward-identity, and their contributions possess particular factors. This
work can help to distinguish the important two loop diagrams giving corrections
to lepton MDM.Comment: 12 pages, 3 figure
The extended BLMSSM with a 125 GeV Higgs boson and dark matter
To extend the BLMSSM, we not only add exotic Higgs superfields
to make the exotic lepton heavy, but also introduce
the superfields(,) having couplings with lepton and exotic lepton
at tree level. The obtained model is called as EBLMSSM, which has difference
from BLMSSM especially for the exotic slepton(lepton) and exotic
sneutrino(neutrino). We deduce the mass matrices and the needed couplings in
this model. To confine the parameter space, the Higgs boson mass and
the processes , are
studied in the EBLMSSM. With the assumed parameter space, we obtain reasonable
numerical results according to data on Higgs from ATLAS and CMS. As a cold dark
mater candidate, the relic density for the lightest mass eigenstate of and
mixing is also studied
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