Search for a Low Mass Standard Model Higgs Boson at D0 in ppbar Collisions at s=1.96TeV\sqrt{s}=1.96 TeV

We present combined searches for the Low Mass Standard Model Higgs boson at a center-of-mass energy of $\sqrt{s}=$1.96 TeV, using up to 5 fb$^{-1}$ of data collected with the D0 detector at the Fermilab Tevatron collider. The major contributing processes are associated production ($WH\to l\nu bb$, $ZH\to\nu\nu bb$, $ZH\to ll bb$). The significant improvements across the full mass range resulting from the larger data sets and improved analyses as well as future prospects are discussed

Soft QCD at Tevatron

Experimental studies of soft Quantum Chromodynamics (QCD) at Tevatron are reported in this note. Results on inclusive inelastic interactions, underlying events, double parton interaction and exclusive diffractive production and their implications to the Large Hadron Collider (LHC) physics are discussed

Measurement of Z/γ\gamma+jet+X and γ\gamma+b/c+X Cross Sections with the D0 Detector

We present measurements of differential cross sections for the inclusive $Z/\gamma^*$ + jet production and the inclusive photon plus heavy flavor production in a data sample of 1fb$^{-1}$ collected with the D{\O}detector in proton-antiproton collisions at $\sqrt{s}$=1.96 TeV. In the first measurement, we compare kinematic distributions of the $Z/\gamma^*$ and the jets as well as various angles of the $Z$+jet system with different Monte Carlo event generators and next-to-leading order perturbative QCD (NLO pQCD) predictions with non-perturbative corrections applied. In the second measurement, we compare the results with NLO pQCD predictions, covering photon transverse momenta 30-150 GeV, photon rapidities $|y^{\gamma}| < 1.0$, jet rapidities $|y^{jet}| 15$ GeV

Experimental aspects of jet physics at LHC

Jet physics provides a powerful tool to investigate interaction properties of quarks and gluons. These studies have been possible at an energy never investigated before at LHC. In this proceedings we review the main characteristics of experimental methods to measure jets in proton-proton collisions at center-of-mass energies of 7 and 8 TeV. Novel methods are expected to play an important role for searching new physics at center-of-mass energy of 13 TeV.Comment: Proceedings of the Summer School and Workshop New Trends in High-Energy Physics and QC

Rich or poor: Who should pay higher tax rates?

A dynamic agent model is introduced with an annual random wealth multiplicative process followed by taxes paid according to a linear wealth-dependent tax rate. If poor agents pay higher tax rates than rich agents, eventually all wealth becomes concentrated in the hands of a single agent. By contrast, if poor agents are subject to lower tax rates, the economic collective process continues forever.Comment: 5 pages, 3 figure

Broad Histogram: An Overview

The Broad Histogram is a method allowing the direct calculation of the energy degeneracy $g(E)$. This quantity is independent of thermodynamic concepts such as thermal equilibrium. It only depends on the distribution of allowed (micro) states along the energy axis, but not on the energy changes between the system and its environment. Once one has obtained $g(E)$, no further effort is needed in order to consider different environment conditions, for instance, different temperatures, for the same system. The method is based on the exact relation between $g(E)$ and the microcanonical averages of certain macroscopic quantities $N^{\rm up}$ and $N^{\rm dn}$. For an application to a particular problem, one needs to choose an adequate instrument in order to determine the averages $$and$$, as functions of energy. Replacing the usual fixed-temperature canonical by the fixed-energy microcanonical ensemble, new subtle concepts emerge. The temperature, for instance, is no longer an external parameter controlled by the user, all canonical averages being functions of this parameter. Instead, the microcanonical temperature $T_{m}(E)$ is a function of energy defined from $g(E)$ itself, being thus an {\bf internal} (environment independent) characteristic of the system. Accordingly, all microcanonical averages are functions of $E$. The present text is an overview of the method. Some features of the microcanonical ensemble are also discussed, as well as some clues towards the definition of efficient Monte Carlo microcanonical sampling rules.Comment: 32 pages, tex, 3 PS figure