Study of anomalous top quark FCNC interactions via tWtW-channel of single top

The potential of the LHC for investigation of anomalous top quark interactions with gluon ($tug,tcg$) through the production of $tW$-channel of single top quark is studied. In the Standard Model, the single top quarks in the $tW$-channel mode are charge symmetric meaning that $\sigma(pp\to t+W^{-}) = \sigma(pp\to \bar{t}+W^{+})$. However, the presence of anomalous FCNC couplings leads to charge asymmetry. In this paper a method is proposed in which this charge asymmetry may be used to constrain anomalous FCNC couplings. The strength of resulting constraints is estimated for the LHC for the center of mass energies of 7 and 14 TeV.Comment: 13 pages, 4 figures, new references adde

Maximizing Social Welfare Subject to Network Externalities: A Unifying Submodular Optimization Approach

We consider the problem of allocating multiple indivisible items to a set of networked agents to maximize the social welfare subject to network externalities. Here, the social welfare is given by the sum of agents' utilities and externalities capture the effect that one user of an item has on the item's value to others. We first provide a general formulation that captures some of the existing models as a special case. We then show that the social welfare maximization problem benefits some nice diminishing or increasing marginal return properties. That allows us to devise polynomial-time approximation algorithms using the Lovasz extension and multilinear extension of the objective functions. Our principled approach recovers or improves some of the existing algorithms and provides a simple and unifying framework for maximizing social welfare subject to network externalities

Electromagnetically controlled multiferroic thermal diode

We propose an electromagnetically tunable thermal diode based on a two phase multiferroics composite. Analytical and full numerical calculations for prototypical heterojunction composed of Iron on Barium titanate in the tetragonal phase demonstrate a strong heat rectification effect that can be controlled externally by a moderate electric field. This finding is of an importance for thermally based information processing and sensing and can also be integrated in (spin)electronic circuits for heat management and recycling.Comment: Accepted in Phys. Rev.