S. Wulck

q-deformation and instability of the phonon spectrum in 4He

We present an application of a q-deformed system to phonons in 4He. We show that a discrepancy between theory and experiments concerning the stability of phonon spectrum can be overcome when we treat the gas of phonon excitations in 4He as an ideal deformed bosonic gas in a ν0 inequivalent representation. Our results are compared with data from 4He specific heat measurements for T<1K and we reproduce within 5% of accuracy the curves resulting from least-squares fits of those data.

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.

Non-relativistic q-gases with low critical temperatures

We propose a deformed q-oscillator system that allows the study of its thermodynamic properties when a deformation parameter q<1. Our analysis shows that deformation is somehow connected to λ-point transitions and that the different values of the deformation parameters can either favor criticality or render it more difficult to attain. We show that in the non-relativistic case the critical temperature of condensation of the system presented can be much smaller than in the non-deformed ideal bosonic gas.

q-Deformation and Energy Deficit in Liquid Helium Phonon Spectrum

We present an application of an ideal bosonic q-gas in a ν0 inequivalent representation to the phonons in 4He and discuss the role of q-deformation as a possible mechanism to supply the energy deficit that forbiddens one-phonon decay into two phonons when the constant γ in the phonon anomalous dispersion relation (ωph = c0p(1 - γp2)) is positive.

On new gauge boson signals according to the littlest higgs model in future e+ e- colliders

There is a recent proposal of identifying the Higgs particle of the Standard Model as a pseudo Nambu-Goldstone boson. This new broken symmetry introduces new particles and new interactions. Among these new interactions a central role to get an experimental signal of a new physics is played by the new neutral gauge bosons, AH and ZH. We study the associated production of general new neutral gauge boson Z¢ and a hard photon in the process e+ + e- ® m + + µ- + g. For MAH < OS we show that the hard photon energy distribution in e+ + e- ® g + f + f can present a model dependence and establish the theoretical origin of a new possible heavy neutral gauge boson.

Asymmetries in the littlest Higgs model

Little Higgs models were recently proposed as an alternative for models of electroweak symmetry breaking. They can be regarded as one of the important candidates of the new physics beyond the Standard Model. We consider here the phenomenology of the minimal model of this type, the ”Littlest Higgs Model” (LHM). It predicts the existence of the new gauge bosons ZH and AH . We calculate the contributions of these new particles to the forward-backward and left-right asymmetries in the processes e + +e i i! f + ¯ f . We study the possibility of detecting the lightest new gauge boson, AH , in the future e+e- colliders with c.m. energies of 500 GeV and 1 TeV and compare the LHM predictions with other models.