Biology's next top model

Evolution: Biology's next top model?

Some say it could have been a global cooling event brought on by falling greenhouse-gas levels. Others argue that it was the drifting continents, which opened up Drake Passage and kick-started frigid, circumpolar currents. Whatever the reason, to the fish that lived on the Antarctic shelf about 34 million years ago, all that mattered was that it was getting cold, very cold. As the water tempera...

Regularization at the next-to-leading order in the top-mode standard model without gauge bosons

We study Higgs condensation H ∼ t̄t in the top-mode standard model at the next-to-leading (NTL) order in 1/Nc, by calculating the effective potential as a function of a hard mass term σ0 of the top quark. We include the effects of the third generation quarks, the Higgs and the Goldstone fields, and the leading QCD effects, but not the effects of the transverse components of the electroweak gauge...

Top Quark Pair Production at Threshold: Complete Next-to-next-to-leading Order Relativistic Corrections

The complete next-to-next-to-leading order (i.e. O(v2), O(vαs) and O(αs)) relativistic corrections to the total photon mediated tt̄ production cross section at threshold are presented in the framework of nonrelativistic quantum chromodynamics. The results are obtained using semi-analytic methods and “direct matching”. The size of the next-to-next-to-leading order relativistic corrections is foun...

Security Impacts of Next Generation Set-top Boxes

Top mass effects in Higgs production at next-to-next-to-leading order QCD: virtual corrections

Top quark mass suppressed terms are calculated for the virtual amplitude for Higgs production in gluon fusion at three-loop level, i.e. O(α3 s ). The method of asymptotic expansions in its automated form is used to evaluate the first three non-vanishing orders in terms of M H /M t , where the first order corresponds to the known results of the effective Lagrangian approach.