17,503 research outputs found
Probing Gravitational Dark Matter
So far all evidences of dark matter (DM) come from astrophysical and
cosmological observations, due to gravitational interactions of the DM. It is
possible that the true DM particle in the universe joins gravitational
interactions only, but nothing else. Such a Gravitational DM (GDM) acts as a
weakly interacting massive particle (WIMP), which is conceptually simple and
attractive. In this work, we explore this direction by constructing the
simplest scalar GDM particle . It is a odd singlet under the
standard model (SM) gauge group, and naturally joins the unique dimension-4
interaction with Ricci curvature, , where is the
dimensionless nonminimal coupling. We demonstrate that this gravitational
interaction , together with Higgs-curvature nonminimal
coupling term , induces effective couplings between
and SM fields which can account for the observed DM thermal relic
abundance. We analyze the annihilation cross sections of GDM particles and
derive the viable parameter space for realizing the DM thermal relic density.
We further study the direct/indirect detections and the collider signatures of
such a scalar GDM. These turn out to be highly predictive and testable.Comment: 33pp, JCAP Final Version. Only minor rewordings, references adde
Systematic mutational analysis of the cation-independent mannose 6-phosphate/insulin-like growth factor II receptor cytoplasmic domain - An acidic cluster containing a key aspartate is important for function in lysosomal enzyme sorting
We have used systematic mutational analysis to identify signals in the 166-residue murine cation-independent mannose 6-phosphate/insulin-like growth factor II receptor cytoplasmic domain required for efficient sorting of lysosomal enzymes. Alanine cluster mutagenesis on all conserved residues apart from the endocytosis signal demonstrates that the major sorting determinant is a conserved casein kinase II site followed by a dileucine motif (157DDSDEDLL164). Small deletions or additions outside this region have severe to mild effects, indicating that context is important. Single residue mutagenesis indicates that cycles of serine phosphorylation/dephosphorylation are not obligatory for sorting. In addition, the two leucine residues and four of the five negatively charged residues can readily tolerate conservative substitutions. In contrast, aspartate 160 could not tolerate isoelectric or isosteric substitutions, implicating it as a critical component of the sorting signal
Higgs Gravitational Interaction, Weak Boson Scattering, and Higgs Inflation in Jordan and Einstein Frames
We study gravitational interaction of Higgs boson through the unique
dimension-4 operator , with the Higgs doublet and the
Ricci scalar curvature. We analyze the effect of this dimensionless nonminimal
coupling on weak gauge boson scattering in both Jordan and Einstein
frames. We explicitly establish the longitudinal-Goldstone boson equivalence
theorem with nonzero coupling in both frames, and analyze the unitarity
constraints. We study the -induced weak boson scattering cross sections at
O(1-30)TeV scales, and propose to probe the Higgs-gravity coupling via weak
boson scattering experiments at the LHC(14TeV) and the next generation pp
colliders (50-100TeV). We further extend our study to Higgs inflation, and
quantitatively derive the perturbative unitarity bounds via coupled channel
analysis, under large field background at the inflation scale. We analyze the
unitarity constraints on the parameter space in both the conventional Higgs
inflation and the improved models in light of the recent BICEP2 data.Comment: 40pp, JCAP Final Version. Use jcappub.sty, only minor rewordings,
references adde
- …