12 research outputs found
Cosmic Flows on 100 Mpc/h Scales: Standardized Minimum Variance Bulk Flow, Shear and Octupole Moments
The low order moments, such as the bulk flow and shear, of the large scale
peculiar velocity field are sensitive probes of the matter density fluctuations
on very large scales. In practice, however, peculiar velocity surveys are
usually sparse and noisy, which can lead to the aliasing of small scale power
into what is meant to be a probe of the largest scales. Previously, we
developed an optimal ``minimum variance'' (MV) weighting scheme, designed to
overcome this problem by minimizing the difference between the measured bulk
flow (BF) and that which would be measured by an ideal survey. Here we extend
this MV analysis to include the shear and octupole moments, which are designed
to have almost no correlations between them so that they are virtually
orthogonal. We apply this MV analysis to a compilation of all major peculiar
velocity surveys, consisting of 4536 measurements. Our estimate of the BF on
scales of ~ 100 Mpc/h has a magnitude of |v|= 416 +/- 78 km/s towards Galactic
l = 282 degree +/- 11 degree and b = 6 degree +/- 6 degree. This result is in
disagreement with LCDM with WMAP5 cosmological parameters at a high confidence
level, but is in good agreement with our previous MV result without an
orthogonality constraint, showing that the shear and octupole moments did not
contaminate the previous BF measurement. The shear and octupole moments are
consistent with WMAP5 power spectrum, although the measurement noise is larger
for these moments than for the BF. The relatively low shear moments suggest
that the sources responsible for the BF are at large distances.Comment: 13 Pages, 7 figures, 4 tables. Some changes to reflect the published
versio
Exclusive Signals of an Extended Higgs Sector
Expectations for the magnitude of Higgs boson signals in standard Higgs
search channels at the LHC relative to Standard Model (SM) expectations are
investigated within the framework of various types of CP and flavor conserving
two Higgs doublet models (2HDMs). Signals of the SM-like Higgs boson in
different classes of 2HDM may be parameterized in terms of particular
two-dimensional sub-spaces of the general four-dimensional space of Higgs
couplings to the massive vector bosons, top quark, bottom quark, and tau
lepton. We find fairly strong correlations among the inclusive di-photon
channel and the exclusive di-photon and di-tau channels from vector boson
fusion or associated production. Order one deviations from SM expectations in
some of these channels could provide discriminating power among various types
of 2HDMs. The ratio of exclusive di-photon to di-tau channels is particularly
sensitive to deviations from SM expectations. We also emphasize that deviations
from SM expectations in standard Higgs search channels may imply observable
signals of non-SM-like Higgs bosons in some of these same channels, in
particular in di-photon and di-vector boson channels. The results cataloged
here provide a roadmap for interpreting standard Higgs search channels in the
context of 2HDMs.Comment: 24 pages, 14 figures, 3 tables; v2: minor corrections, extended
discussion of current Higgs signals; version appearing in JHE