M. A. B. do Vale

Signature for heavy Majorana neutrinos in hadronic collisions

The production and decay of new possible heavy Majorana neutrinos are analyzed in hadronic collisions. New bounds on the mixing of these particles with standard neutrinos are estimated according to a fundamental representation suggested by grand unified models. A clear signature for these Majorana neutrinos is given by same-sign dileptons plus a charged weak vector boson in the final state. We discuss the experimental possibilities for the future Large Hadron Collider (LHC) at CERN.

Torsion Phenomenology at the LHC

We explore the potential of the CERN Large Hadron Collider (LHC) to test the dynamical torsion parameters. The form of the torsion action can be established from the requirements of consistency of effective quantum field theory. The most phenomenologically relevant part of the torsion tensor is dual to a massive axial vector field. This axial vector has geometric nature, that means it does not belong to any representation of the gauge group of the SM extension or GUT theory. At the same time, torsion should interact with all fermions, that opens the way for the phenomenological applications. We demonstrate that LHC collider can establish unique constraints on the interactions between fermions and torsion field considerably exceeding present experimental lower bounds on the torsion couplings and its mass. It is also shown how possible nonuniversal nature of torsion couplings due to the renormalization group running between the Planck and TeV energy scales can be tested via the combined analysis of Drell-Yan and tt? production processes.

Discriminating among the theoretical origins of new heavy Majorana neutrinos at CERN LHC

A study on the possibility of distinguishing new heavy Majorana neutrino models at LHC energies is presented. The experimental confirmation of standard neutrinos with nonzero mass and the theoretical possibility of lepton number violation find a natural explanation when new heavy Majorana neutrinos exist. These new neutrinos appear in models with new right-handed singlets, in new doublets of some grand unified theories and left-right symmetrical models. It is expected that signals of new particles can be found at the CERN high-energy hadron collider (LHC). We present signatures and distributions that can indicate the theoretical origin of these new particles. The single and pair production of heavy Majorana neutrinos are calculated and the model dependence is discussed. Same-sign dileptons in the final state provide a clear signal for the Majorana nature of heavy neutrinos, since there is lepton number violation. Mass bounds on heavy Majorana neutrinos allowing model discrimination are estimated for three different LHC luminosities.

New heavy charged leptons at future high energy electron-positron colliders

Abstract.New heavy charged lepton production and decay signatures at future electron-positron colliders are investigated at

Neutral heavy lepton production at next high energy e + e − linear colliders

\sqrt {s}=500

A proposal for a different chi-square function for Poisson distributions

GeV. The consequences of model dependence for vector singlets and vector doublets are studied. Distributions are calculated including hadronization effects and experimental cuts that suppress the standard model background. The final state leptonic energy distributions are shown to give a very clear signature for heavy charged leptons.

Single neutral heavy lepton production at electron–muon colliders

The discovery potential for detecting new heavy Majorana and Dirac neutrinos at some recently proposed high energy

Dirac and Majorana heavy neutrinos at LEP II

{e}^{+}{e}^{\ensuremath{-}}

Torsion limits from t t ¯ production at the LHC

colliders is discussed. These new particles are suggested by grand unified theories and superstring-inspired models. For these models the production of a single heavy neutrino is shown to be more relevant than pair production when comparing cross sections and neutrino mass ranges. The process

ENERGY-ENERGY CORRELATIONS AND HEAVY AND LIGHT QUARK ENERGY LOSSES AT LHC

{e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\ensuremath{\nu}{e}^{\ifmmode\pm\else\textpm\fi{}}{W}^{\ensuremath{\mp}}