26,449 research outputs found
Membrane contact sites - an interesting species, an interesting mix
In this issue of EMBO reports, Loewen and colleagues reveal a role for plasma membrane–endoplasmic reticulum contact sites in regulating phosphatidylcholine synthesis in budding yeast
High Scale Boundary Conditions in Models with Two Higgs Doublets
We investigate high scale boundary conditions on the quartic Higgs-couplings
and their -functions in the Type-II Two Higgs Doublet Model and the
Inert Doublet Model. These conditions are associated with two possible UV
physics scenarios: the Multiple Point Principle, in which the potential
exhibits a second minimum at , and Asymptotic Safety, where the scalar
couplings run towards an interacting UV fixed point at high scales. We employ
renormalisation group running at two-loops and apply theoretical and
experimental constraints to their parameter spaces. We find neither model can
simultaneously accommodate the MPP whilst also providing realistic masses for
both the Higgs and the top quark. However, we do find regions of parameter
space compatible with Asymptotic Safety.Comment: 25 pages, 13 figures (25 plots); v3: version accepted for publicatio
The gene complement of the ancestral bilaterian - was Urbilateria a monster?
Expressed sequence tag analyses of the annelid Pomatoceros lamarckii, recently published in BMC Evolutionary Biology, are consistent with less extensive gene loss in the Lophotrochozoa than in the Ecdysozoa, but it would be premature to generalize about patterns of gene loss on the basis of the limited data available
An Orthogonal Test of the -functions Ratios Conjecture, II
Recently Conrey, Farmer, and Zirnbauer developed the L-functions Ratios
conjecture, which gives a recipe that predicts a wealth of statistics, from
moments to spacings between adjacent zeros and values of L-functions. The
problem with this method is that several of its steps involve ignoring error
terms of size comparable to the main term; amazingly, the errors seem to cancel
and the resulting prediction is expected to be accurate up to square-root
cancellation. We prove the accuracy of the Ratios Conjecture's prediction for
the 1-level density of families of cuspidal newforms of constant sign (up to
square-root agreement for support in (-1,1), and up to a power savings in
(-2,2)), and discuss the arithmetic significance of the lower order terms. This
is the most involved test of the Ratios Conjecture's predictions to date, as it
is known that the error terms dropped in some of the steps do not cancel, but
rather contribute a main term! Specifically, these are the non-diagonal terms
in the Petersson formula, which lead to a Bessel-Kloosterman sum which
contributes only when the support of the Fourier transform of the test function
exceeds (-1, 1).Comment: 36 pages, first draf
Linear Collider Physics
The International Linear Collider has a rich physics programme, whatever lies
beyond the standard model. Accurate measurement of the top quark mass is needed
to constrain the model or its extensions. If there is a light Higgs boson the
LHC should see it, but the ILC will pin down its characteristics and test them
against model predictions. If Supersymmetric particles appear the ILC will
measure a complementary set of them to those seen at the LHC, and may allow
extrapolation to the Grand Unified scale. And if a strong electroweak sector is
indicated the ILC will be sensitive to the presence of new structures in
difermion and diboson systems up to higher masses than the direct search range
of the LHC. Beyond the LHC and ILC there could be need for a multi TeV lepton
collider.Comment: Plenary talk at ICHEP 2004, Beijing, 22 August 200
- …