6,133 research outputs found
GeV Scale Asymmetric Dark Matter from Mirror Universe: Direct Detection and LHC Signatures
Mirror universe is a fundamental way to restore parity symmetry in weak
interactions. It naturally provides the lightest mirror nucleon as a unique
GeV-scale asymmetric dark matter particle candidate. We conjecture that the
mirror parity is respected by the fundamental interaction Lagrangian, and its
possible soft breaking arises only from non-interaction terms in the
gauge-singlet sector. We realize the spontaneous mirror parity violation by
minimizing the vacuum Higgs potential, and derive the corresponding Higgs
spectrum. We demonstrate that the common origin of CP violation in the visible
and mirror neutrino seesaws can generate the right amount of matter and mirror
dark matter via leptogenesis. We analyze the direct detections of GeV-scale
mirror dark matter by TEXONO and CDEX experiments. We further study the
predicted distinctive Higgs signatures at the LHC.Comment: 16pp. Plenary talk presented by HJH at the International Symposium on
Cosmology and Particle Astrophysics (CosPA2011). To appear in the conference
proceedings of IJMP. Minor refinement
Interplay between multi-spin and chiral spin interactions on triangular lattice
We investigate the spin- nearest-neighber Heisenberg model with
the four-site ring-exchange and chiral interaction on the
triangular lattice by using the variational Monte Carlo method. The term
induces the quadratic band touching (QBT) quantum spin liquid (QSL) with only a
spinon pairing (without hopping term), the nodal -wave QSL and U(1)
QSL with a finite spinon Fermi surface progressively. The effect of the chiral
interaction can enrich the phase diagram with two interesting chiral
QSLs (topological orders) with the same quantized Chern number and ground-state degeneracy GSD = 2, namely the U(1) chiral spin
liquid (CSL) and Z -wave QSL. The nodal -wave QSL is fragile and
will turn to the Z QSL with any finite within our numerical
calculation. However, in the process from QBT to the Z QSL with the
increase of , an exotic crossover region is found. In this region, the
previous QBT state acquires a small hopping term so that it opens a small gap
at the otherwise band touching points, and leads to an energy minimum which is
energetically more favorable compared to another competitive local minimum from
the Z QSL. We dub this state as the proximate QBT QSL and it gives
way to the Z QSL eventually. Therefore, the cooperation of the
and terms favors mostly the Z -wave QSL, so that this phase
occupies the largest region in the phase diagram
A double neutron star merger origin for the cosmological relativistic fading source PTF11agg?
The Palomar Transient Factory (PTF) team recently reported the discovery of a
rapidly fading optical transient source, PTF11agg. A long-lived scintillating
radio counterpart was identified, but the search for a high energy counterpart
showed negative results. The PTF team speculated that PTF11agg may represent a
new class of relativistic outbursts. Here we suggest that a neutron star
(NS)-NS merger system with a supra-massive magnetar central engine could be a
possible source to power such a transient, if our line of sight is not on the
jet axis direction of the system. These systems are also top candidates for
gravitational wave sources to be detected in the advanced LIGO/Virgo era. We
find that the PTF11agg data could be explained well with such a model,
suggesting that at least some gravitational wave bursts due to NS-NS mergers
may be associated with such a bright electromagnetic counterpart without a
\gamma-ray trigger.Comment: Accepted for publication in ApJ Letter
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