Numerous searches for new phenomena have been carried out using data from proton-antiproton collisions at Fermilab's Tevatron. Final states with leptons give signatures which are relatively unique and generally have small backgrounds. We present many of the latest results from the CDF and D0 collaborations from 0.4-1.2 fb−1 of data. Topics include supersymmetry, extra gauge bosons, Randall-Sundrum gravitons, excited electrons and neutral, long-lived particles.

We present some of the latest updated results on searches for physics beyond the Standard Model at the Tevatron Collider using the full Run 1 data sample of p{anti p} collisions at √s = 1.8 TeV collected with the CDF and D0 detectors. Results are reported relative to searches for squarks and gluinos, scalar top and bottom quarks and superlight gravitino. 95% CL exclusion limits are presented for degenerate states of Technicolor particles [rho]T and [omega]T.

This book reports on the search for a new heavy particle, the Vector-Like Top quark (VLT), in the Large Hadron Collider (LHC) at CERN. The signal process is the pair production of VLT decaying into a Higgs boson and top quark (TT→Ht+X, X=Ht, Wb, Zt). The signal events result in top–antitop quarks final states with additional heavy flavour jets. The book summarises the analysis of the data collected with the ATLAS detector in 2015 and 2016. In order to better differentiate between signals and backgrounds, exclusive taggers of top quark and Higgs boson were developed and optimised for VLT signals. These efforts improved the sensitivity by roughly 30%, compared to the previous analysis. The analysis outcomes yield the strongest constraints on parameter space in various BSM theoretical models. In addition, the book addresses detector operation and the evaluation of tracking performance. These efforts are essential to properly collecting dense events and improving the accuracy of the reconstructed objects that are used for particle identification. As such, they represent a valuable contribution to data analysis in extremely dense environments.

Recent results on searches for new physics at Run II of the Tevatron and highlights from HERA are reported. The searches cover many different final states and a wide range of models. All analyses have at this point led to negative results, but some interesting anomalies have been found.

The high energy physics has made huge steps forward the comprehension of the inner most nature of our universe and the matter we are composed of. The experimental discoveries, and the theories of the last 50 years that the experimental discoveries had confirmed or inspired, made possible to build a theory of the interactions. Weak interactions have been discovered and unified with the Electromagnetic ones in the Standard Model, which is the most widely experimentally tested and confirmed model of this century. The only prediction which is still unconfirmed is the existence of a particle, the Higgs boson, which provides particles with mass, interacting with them, in a spontaneous symmetry breakdown that doesn't violate the natural gauge symmetry of the Lagrangian of the system. One of the ways in which the Standard Model has been tested during the last 20 years is by accelerating ee− (LEP) or p{bar p} (Tevatron) particles in a circular ring and colliding them inside a detector which is designed to reveal the final reaction products. We now have two operating hadron colliders in the world. The Tevatron at Fermilab laboratory of Chicago, collides protons against anti-protons since 1989 and has reached its maximum energy in the mass center of 1.96 TeV since 2001. It has collected approximately 7 fb−1 of data so far, that allowed important discoveries, as the top quark one, B{sub s} mixing, precision measurements of some of the Standard Model free parameters, e.g. the W mass, and search for New Phenomena. The LHC at CERN in Geneva is a proton proton collider and has started the data acquisition in March 2010, at a center of mass energy of 7 TeV, thus beating the world record of the Tevatron. LHC however has not yet either the integrated luminosity nor the detailed understanding of the detectors to start investigating Higgs or di-boson production. The purpose of this work is to analyse the data of the CDF experiment at Tevatron to search for the associate production of a W{sup {+-}} and Z gauge boson, looking for them in the lepton, neutrino plus jets final state, This process is predicted by the Standard Model but not revealed yet in this particular channel, both for its small cross section ([sigma]{sub WW/WZ} H"16 pb−1) and for the huge backgrounds we have to deal with. The WW− or W{sup {+-}}Z in l {bar {nu}}{sub l} j j process has been measured for the first time in [4] and represents the starting point of this work. Our aim is to discriminate W{sup {+-}}Z process from W+W− one requiring the decay of the Z boson in two b-quarks. The evidence of a peak on the invariant mass distribution will allow a tuning of the invariant mass resolution of b-jets. In addition, one of the main motivations for this quest is the similarity of this exactly predicted process with the W{sup {+-}}H associate production signature, for which it represents a test of the searching tools and techniques, as long as an irreducible background that must be understood before such Higgs search is performed.