Effects of the FCNC couplings in production of new heavy quarks within Z' models at the LHC

We study the flavor changing neutral current couplings of new heavy quarks through the Z' models at the LHC. We calculate the cross sections for the signal and the corresponding standard model background processes. Considering the present limits on the mass of new heavy quarks and the Z' boson, we performed an analysis to investigate the parameter space (mixing and mass) through different Z' models. For an FCNC mixing parameter x=0.1 and the Z' mass M_{Z'}=2000 GeV, and new heavy quark mass m_{t'}=700 GeV at the LHC with \sqrt{s}=13 TeV, we find the cross section for single production of new heavy quarks associated with top quarks as 5.8 fb, 3.3 fb, 1.5 fb and 1.2 fb within the Z'_{\eta} , Z'_{\psi} , Z'_{LP} and Z'_{\chi} models, respectively. It is shown that the sensitivity would benefit from the flavor tagging.Comment: 17 pages, 18 figures, update. arXiv admin note: text overlap with arXiv:1003.315

Response functions of an artificial Anderson atom in the atomic limit

We consider the spin and pseudospin (charge) response functions of the exactly soluble Anderson atom model. We demonstrate, in particular, that a deviation from the magnetic Curie-law behaviour, appropriate for a free spin one-half, increases with increasing asymmetry and temperature. In general, oscillator strength is transferred from the spin degrees of freedom to the pseudospin modes. We also consider the negative-U Anderson atom and demonstrate that the pseudospin modes are the relevant low-energy excitations in this case. Especially, the roles of the spin and charge excitations are interchanged upon reversal of the intrasite Coulomb repulsion, U.Comment: 23 pages, 12 figures. Accepted for publication in J. Low Temp. Phy

Anomalous quartic WWγγWW\gamma\gamma couplings in epep collisions at the LHeC and the FCC-he

We conducted a study on measuring $W^+W^-$ production and on the sensitivity limits at $95\%$ Confidence Level on thirteen anomalous couplings obtained by dimension-8 operators which are related to the anomalous quartic $WW\gamma\gamma$ couplings. We consider the main $e^-p \to e^-\gamma^*\gamma^*p \to e^-W^+W^-p$ reaction with the sub-process $\gamma^*\gamma^* \to W^+W^-$ at the Large Hadron electron Collider (LHeC) and the Future Circular Collider-hadron electron (FCC-he). For the LHeC, energies of the $e^-$ beams are taken to be $E_e =60$ and 140 GeV and the energy of the $p$ beams is taken to be $E_p = 7$ TeV. For the FCC-he, energies of the $e^-$ beams are taken to be $E_e =60$ and 140 GeV and the energy of the $p$ beams is taken to be $E_p = 50$ TeV, respectively. It is interesting to notice that the LHeC and the FCC-he will lead to model-independent limits on the anomalous quartic $WW\gamma\gamma$ couplings which are one order of magnitude stringent than the CMS Collaboration limits, in addition to being competitive with other limits reported in the literature.Comment: 28 pages, 10 Figures and 13 Table

Electromagnetic boundary and its realization with anisotropic metamaterial

A set of boundary conditions requiring vanishing of the normal components of the D and B vectors at theboundary surface is introduced and labeled as that of DB boundary. Basic properties of the DB boundary arestudied in this paper. Reflection of an arbitrary plane wave, incident with a complex propagation vector, isanalyzed for the planar DB boundary. It is shown that waves polarized transverse electric TE and transversemagnetic TM with respect to the normal of the boundary are reflected as from respective perfect electricconductor and perfect magnetic conductor planes. The basic problem of current source above the planar DBboundary is solved by applying TE and TM decomposition for the source. Realization of the DB boundary interms of an interface of uniaxially anisotropic metamaterial half-space with zero axial medium parameters isconsidered. It is also shown that such a medium with small axial parameters acts as a spatial filter for wavesincident at the interface which could be used for narrowing the beam of a directive antenna. Application of DBboundary as an isotropic soft surface with low interaction between antenna apertures also appears possible.Peer reviewe