The microscopic mechanism of the metal-insulator transition is studied by orbital-resolved 51V NMR spectroscopy in a prototype of the quasi-one-dimensional system V6O13. We uncover that the transition involves a site-selective d orbital order lifting
twofold orbital degeneracy in one of the two VO6 chains. The other chain leaves paramagnetic moments on the singly occupied dxy orbital across the transition. The two chains respectively stabilize an orbital-assisted spin-Peierls state and an antiferromagnetic long-range order in the ground state. The site-selective Mott transition may be a source of the anomalous metal and the Mott-Peierls duality.
We propose a new method to measure a theoretically well-defined top quark mass at the LHC. This method is based on the weight function method, which we proposed in our preceding paper. It requires only lepton energy distribution and is basically inde
pendent of the production process of the top quark. We perform a simulation analysis of the top quark mass reconstruction with $tbar{t}$ pair production and lepton+jets decay channel at the leading order. The estimated statistical error of the top quark mass is about $0.4$ GeV with an integrated luminosity of $100$ fb$^{-1}$ at $sqrt{s}=14$ TeV. We also estimate some of the major systematic uncertainties and find that they are under good control.
We propose an inclusive analysis of a stransverse mass (m_{T2}) using a hemisphere method for supersymmetry studies at the LHC . The hemisphere method is an algorithm to group collinear and high p_T particles and jets, assuming that there are two of
such groups in a event. The m_{T2} is defined as a function of the unknown LSP mass, two hemisphere momenta, and missing transverse momentum. The kinematical end point of the m_{T2} distribution provides information on the squark and gluino masses. We perform a Monte Carlo simulation to study the inclusive m_{T2} distribution at the LHC. We show that the end point of the inclusive m_{T2} distribution has a cusp-like structure around the true LSP mass. The knowledge of the expected kinematical behavior near the end point for true events is important to establish the end point of the inclusive distribution. We find that the inclusive analysis is useful to obtain the information on the heaviest of the squark/gluino.
