Publications (6) View all
-
Article: A 125 GeV scalar improves the low-energy data support for the top-BESS model
Mikulas Gintner, Josef Juran[show abstract] [hide abstract]
ABSTRACT: We investigate how adding a scalar resonance of a mass 125 GeV affects the low-energy data support for the top-BESS model as well as its low-energy free parameter limits. The top-BESS model is an effective Lagrangian, a modification of the well-known BESS model, with an ambition to describe phenomenology of the lowest bound states of strongly-interacting theories beyond the Standard model. In particular, the SU(2)_{L+R} vector resonance triplet of hypothetical bound states is a centerpiece of BESS-like effective models. The top-BESS model assumes that the triplet couples directly to the third quark generation only. This assumption reflects a possible special standing of the third quark generation, and the top quark in particular, in physics of electroweak symmetry breaking. Our findings suggest that the 125 GeV scalar extension of the top-BESS model results in a higher statistical support for the model. The best-fit values of the model's free parameters are consistent with the top quark having a higher degree of compositeness than the bottom quark.01/2013; -
SourceAvailable from: Mikulas Gintner
Article: A brief outline of the top-BESS model
Mikulas Gintner, Josef Juran, Ivan Melo[show abstract] [hide abstract]
ABSTRACT: This is a brief outline of the top-BESS model and its properties. The top-BESS model is the higgsless effective description of the strong electroweak symmetry breaking with a single new SU(2)_L+R triplet vector resonance. In contrast with the universality of the fermion interactions of the BESS model, the top-BESS vector resonance couples directly to the third quark generation only. The complete formulation of the model along with its phenomenology can be found in arXiv:1107.0570.08/2011; -
SourceAvailable from: Josef Juran
Article: Top-BESS model and its phenomenology
Mikulas Gintner, Josef Juran, Ivan Melo[show abstract] [hide abstract]
ABSTRACT: We introduce the top-BESS model which is the effective description of the strong electroweak symmetry breaking with a single new SU(2)_L+R triplet vector resonance. The model is a modification of the BESS model in the fermion sector. The triplet couples to the third generation of quarks only. This approach reflects a possible extraordinary role of the top quark in the mechanism of electroweak symmetry breaking. The low-energy limits on the model parameters found provide hope for finding sizable signals in the LHC Drell-Yan processes as well as in the s-channel production processes at the ILC. However, there are regions of the model parameter space where the interplay of the direct and indirect fermion couplings can hide the resonance peak in a scattering process even though the resonance exists and couples directly to top and bottom quarks.07/2011; -
SourceAvailable from: Josef Juran
Article: Joint description of the e+e- annihilation into both four-pion channels
Josef Juran, Peter Lichard[show abstract] [hide abstract]
ABSTRACT: The e+e- --> pi+pi-pi0pi0 reaction cross section as a function of the incident energy is calculated using a model that is an extension of our recently published model of the e+e- annihilation into four charged pions. The latter considered the intermediate states with the pi, rho, and a_1 mesons and fixed the mixing angle of the a_1-rho-pi Lagrangian and other parameters by fitting the cross section data. Here we supplement the original intermediate states with those containing omega(782) and h_1(1170), but keep unchanged the values of those parameters that enter both charged and mixed channel calculations. The inclusion of omega is vital for obtaining a good fit to the cross section data, while the intermediate states with h_1 further improve it. Finally, we merge our models of the e+e- --> pi+pi-pi0pi0 and e+e- --> pi+pi-pi+pi- reactions and obtain a simultaneous good fit.03/2008; -
SourceAvailable from: Josef Juran
Article: Electron-positron annihilation into four charged pions and the a_1-rho-pi Lagrangian
Peter Lichard, Josef Juran[show abstract] [hide abstract]
ABSTRACT: The excitation curve of e+e- annihilation into four charged pions in the rho(770) region is calculated using three existing models with rho mesons and pions in intermediate states supplemented by Feynman diagrams with the a_1(1260)pi intermediate states. A two-term phenomenological Lagrangian of the a_1-rho-pi interaction is used. The mixing angle is determined by fitting the e+e- --> pi+pi-pi+pi- cross section data of the Novosibirsk CMD-2 collaboration and also its combination with the low-energy part of the BaBar collaboration data. It is shown that the inclusion of the a_1-pi intermediate states succeeds in obtaining a good agreement with the data on both cross section and the rho^0 --> pi+pi-pi+pi- decay width. When moving to energies above 1 GeV, the rho(1450) and rho(1700) resonances are taken into account to get excellent agreement with the BaBar data over the full energy range up to 4.5 GeV.02/2006;