A new window on Strange Quark Matter as the ground state of strongly interacting matter

If strange quark matter is the true ground state of matter, it must have lower energy than nuclear matter. Simultaneously, two-flavour quark matter must have higher energy than nuclear matter, for otherwise the latter would convert to the former. We show, using an effective chiral lagrangian, that the existence of a new lower energy ground state for two-flavour quark matter, the pion condensate, shrinks the window for strange quark matter to be the ground state of matter and sets new limits on the current strange quark mass

NLO predictions for t-channel production of single top and fourth generation quarks at hadron colliders

We present updated NLO predictions for the electroweak t-channel production of heavy quarks at the Tevatron and at the LHC. We consider production of single top and fourth generation t' starting from both 2 to 2 and 2 to 3 Born processes. Predictions for tb' and t'b' cross sections at NLO are also given for the first time. A thorough study of the theoretical uncertainties coming from parton distribution functions, renormalisation and factorisation scale dependence and heavy quark masses is performed.Comment: 25 pages, 8 figure

The frictional Schr\"odinger-Newton equation in models of wave function collapse

Replacing the Newtonian coupling G by -iG, the Schrodinger-Newton equation becomes ``frictional''. Instead of the reversible Schrodinger-Newton equation, we advocate its frictional version to generate the set of pointer states for macroscopic quantum bodies.Comment: 6pp LaTeX for J.Phys.Conf.Ser.+2 figs. Talk given at the Int. Workshop DICE2006 "Quantum Mechanics between Decoherence and Determinism: new aspects from particle physics to cosmology" Piombino, Sept 11-15, 200

Intensive Care Usage by HIV-Positive Patients in the HAART Era

In the 1980s the outlook for patients with the acquired immunodeficiency syndrome (AIDS) and critical illness was poor. Since then several studies of outcome of HIV+ patients on ICU have shown improving prognosis, with anti-retroviral therapy playing a large part. We retrospectively examined intensive care (ICU) admissions in a large HIV unit in London. Between April 2001 and April 2006 43 patients were admitted to the ICU. The mean age of patients was 44 years and 74% were male. Fifty-six percent of admissions were receiving anti-retroviral therapy and 44% had an AIDS defining diagnosis. The median CD4 count was 128 cells/mL and the median APACHE II score was 21. The commonest diagnostic ICU admission category was respiratory disease. This group experienced higher mortality despite slightly lower APACHE II scores, though this did not achieve statistical significance. The follow up period was one year or until April 2007, when data were censored. ICU mortality was 33%, in hospital mortality was 51% and overall mortality at the end of the study period was 67%. Median survival was 1008 days. The CD4 count did not predict long-term survival, although the sample size was too small for this to be conclusive

Proton lifetime bounds from chirally symmetric lattice QCD

We present results for the matrix elements relevant for proton decay in Grand Unified Theories (GUTs). The calculation is performed at a fixed lattice spacing a^{-1}=1.73(3) GeV using 2+1 flavors of domain wall fermions on lattices of size 16^3\times32 and 24^3\times64 with a fifth dimension of length 16. We use the indirect method which relies on an effective field theory description of proton decay, where we need to estimate the low energy constants, \alpha = -0.0112(25) GeV^3 and \beta = 0.0120(26) GeV^3. We relate these low energy constants to the proton decay matrix elements using leading order chiral perturbation theory. These can then be combined with experimental bounds on the proton lifetime to bound parameters of individual GUTs.Comment: 17 pages, 9 Figure

QCD with domain wall quarks

We present lattice calculations in QCD using a variant of Kaplan fermions which retain the continuum SU(N)xSU(N) chiral symmetry on the lattice in the limit of an infinite extra dimension. In particular, we show that the pion mass and the four quark matrix element related to K_0-K_0-bar mixing have the expected behavior in the chiral limit, even on lattices with modest extent in the extra dimension, e.g. N_s=10.Comment: Published version. Minor differences from original. LaTeX, 12 pages including 2 PostScript figure