arXiv subjects

George Triantaphyllou

Publications and source records attributed to George Triantaphyllou.

18 recordsLinked to original sources

arXiv2016

Mirror mesons at the Large Hadron Collider (LHC)

The existence of mirror partners of Standard-Model fermions offers a viable alternative to a fundamental BEH mechanism, with the coupling corresponding to the gauged mirror generation symmetry becoming naturally strong at energies around 1 TeV. The resulting non-perturbative processes produce dynamical katoptron masses which might range from 0.1 to 1.15 TeV in a way circumventing usual problems with the S parameter. Moreover, they create mirror mesons belonging in two main groups, with masses differing from each other approximately by a factor of six and which might range approximately from 0.1 to 2.8 TeV. Since the corresponding phenomenology expected at hadron colliders is particularly rich, some interesting mirror-meson cross-sections are presented, something that might also lead to a deeper understanding of the underlying mirror fermion structure. Among other findings, results in principle compatible with indications from LHC concerning decays of new particles to two photons are analyzed.

physics.gen-ph↗

arXiv2012

Towards E_8 * E_8 Unification

We present a framework having the potential to unify the fundamental interactions in nature by introducing new degrees of freedom. An attempt is made to explain the hierarchy between the weak scale and the coupling unification scale, which is found to lie close to Planck energies. A novel process leading to the emergence of symmetry is proposed, which not only reduces the arbitrariness of the scenario proposed but is also followed by significant cosmological implications. Phenomenology includes the probability of detection of mirror fermions via the corresponding composite bosonic states and the relevant quantum corrections at the LHC.

physics.gen-ph↗

arXiv2002

Understanding the genesis of mass: a mystery pointing towards the mirror world

We give a pedagogical and concise presentation of dynamical mass generation involving strongly-interacting mirror fermions. As a paradigm which has been explicitly shown to predict correctly the weak scale and the weak angle and thus addressing successfully the essence of the hierarchy problem of energy scales (contrary to "supersymmetric" or "extra-dimension" models) and the unification of fundamental forces, it might have already manifested indirectly its validity experimentally, as first noted by the author in 1998, via the bottom-quark forward-backward asymmetry and the related coupling parameter A_b. After a decade during which the particle-physics community was frequently misled by a particularly obscurantist interpretation of the L.E.P./S.L.C. precision data, this approach emerges as a strong candidate for new physics beyond the standard model of elementary particles to be thoroughly tested in the forthcoming high-energy experiments.

hep-ph↗

arXiv2001

Weak scale: Dynamical determination versus accidental stabilization

Is it a mere accident that the weak scale is exactly so much smaller than the Planck scale, and at the same time exactly so much larger than the QCD scale? Or are the experimentally-measured values of the corresponding gauge couplings enough to help us determine dynamically these energy scales? And if nature has indeed offered us the possibility of such a determination, why dismiss it and fix these scales instead by means of arbitrary parameters within a multitude of jejune theoretical frameworks which make this wonderful hierarchy seem fortuitous?

hep-ph↗

arXiv2001

Mass generation and the dynamical role of the Katoptron Group

Heavy mirror fermions along with a new strong gauge interaction capable of breaking the electroweak gauge symmetry dynamically were recently introduced under the name of katoptrons. Their main function is to provide a viable alternative to the Standard-Model Higgs sector. In such a framework, ordinary fermions acquire masses after the breaking of the strong katoptron group which allows mixing with their katoptron partners. The purpose of this paper is to study the elementary-scalars-free mechanism responsible for this breaking and its implications for the fermion mass hierarchies.

hep-ph↗

arXiv2000

Strongly-interacting fermions from a higher-dimensional unified gauge theory

The method of coset-space dimensional reduction is employed in order to proceed from a gauged E_8 * E_8' unified theory defined in 10 dimensions to 4 dimensions. The resulting theory comprises the Standard Model along with a strongly-interacting fermion sector which breaks the electroweak symmetry dynamically at the right scale.

hep-ph↗

arXiv1999

New physics with mirror particles

The introduction of mirror fermions with masses between the weak scale and 1 TeV could offer a dynamical origin to the standard-model electro-weak symmetry breaking mechanism. The purpose of this work is to study the dynamics needed in order to render models with such a fermion content phenomenologically acceptable.

hep-ph↗

arXiv1999

Mirror fermions and the hierarchy problem

The introduction of strongly-interacting mirror fermions with masses between the weak scale and 1 TeV could offer a viable alternative to the Higgs mechanism. The framework provided solves the hierarchy problem naturally and predicts a rich phenomenology for present and future experiments.

hep-ph↗

arXiv1999

Dynamical symmetry breaking with mirror fermions

Mirror fermions with masses around the weak scale could break dynamically the electroweak symmetry if they were coupled with a new strong interaction. The purpose of this talk is to show what sort of dynamics are needed in order to render such theories phenomenologically viable.

hep-ph↗

arXiv1999

Gap equation in finite-temperature three-dimensional QED beyond the bare-vertex approximation

Dynamical mass generation in a three-dimensional version of finite-temperature QED is studied with the help of Schwinger-Dyson equations in the real-time formalism. We go beyond the bare-vertex approximation and include wave-function renormalization effects. This introduces a system of two integral equations which are solved numerically. In order to increase the reliability of the results, fermion and photon self-energies varying independently with energy and momentum are used. The method applied enables a detailed study of the behaviour of the theory with increasing temperature and number of fermion flavours.

hep-ph↗

arXiv1999

Strategy towards Mirror-fermion Signatures

The existence of mirror fermions interacting strongly under a new gauge group and having masses near the electroweak scale has been recently proposed as a viable alternative to the standard-model Higgs mechanism. The main purpose of this work is to investigate which specific experimental signals are needed to clearly differentiate the mirror-fermion model from other new-physics models. In particular, the case is made for a future large lepton collider with c.o.m. energies of roughly 4 TeV or higher.

hep-ph↗

arXiv1999

Neutrinos, their Partners and Unification

Efforts to unify group-theoretically the standard-model gauge interactions with the generation structure of fermions and their mirror partners should be accompanied with the unification of the corresponding gauge couplings. In this paper the possibility of such a unification is studied and conclusions on possible symmetry-breaking channels and scales, as well as on the fermion content of the theory, are drawn. The breaking of some of the symmetries allows various Majorana masses for neutrinos and their mirror partners, so these are studied next. Implications to neutrino mixings and mass hierarchies in connection with recent experimental results, as well as to electroweak precision tests, are then discussed.

hep-ph↗

arXiv1998

Fermion mass-function in thermal QED3

The gap equation for fermions in a version of thermal QED in three dimensions is studied numerically in the Schwinger-Dyson formalism. The interest in this theory has been recently revived since it has been proposed as a model of high-temperature superconductors. We include wave-function renormalization in our equations and use a non-bare vertex. We then have to solve a system of two integral equations by a relaxation algorithm. Fermion and photon self-energies varying independently with energy and momentum are used, which should produce more accurate results than in the previous literature. The behaviour of the theory with increasing temperature and number of fermion flavours is then carefully analyzed.

hep-ph↗

arXiv1998

Mirror Families in Electro-weak Symmetry Breaking

We study symmetry breaking in a left-right symmetric extension of the Standard Model with mirror fermions, one for each Standard-Model fermion. The new particles assist a top-quark condensate in breaking electro-weak symmetry. Half of the fermions acquire electro-weak-invariant masses at around 500 GeV and would be probably accessible at future high-energy experiments like LHC or NLC. The contributions to the S and T parameters are small and negative in accordance with electro-weak precision data.

hep-ph↗

arXiv1998

Dynamical Mass Generation in a Finite-Temperature Abelian Gauge Theory

We write down the gap equation for the fermion self-energy in a finite-temperature abelian gauge theory in three dimensions. The instantaneous approximation is relaxed, momentum-dependent fermion and photon self-energies are considered, and the corresponding Schwinger-Dyson equation is solved numerically. The relation between the zero-momentum and zero-temperature fermion self-energy and the critical temperature T_c, above which there is no dynamical mass generation, is then studied. We also investigate the effect which the number of fermion flavours N_f has on the results, and we give the phase diagram of the theory with respect to T and N_f.

hep-ph↗

arXiv1994

A New Paradigm for the Fermion Generations

A new mechanism is proposed to explain the appearance of the three known fermion generations in a natural way. The underlying idea is based on the discreteness of the spectrum of solutions of the gap equation appearing in models of dynamical chiral symmetry breaking. Within such a framework, the number of parameters needed to describe the experimentally observed fermion spectrum is drastically reduced. The phenomenological consequences of such a mechanism are carefully discussed, in order to explore its viability.

hep-ph↗

arXiv1993

QED Radiative Corrections to the Decay $π^{0} \rightarrow e^{+}e^{-}$

In view of the recent interest in the decays of mesons into a pair of light leptons, a computation of the QED radiative corrections to the decay of $π^{0}$ into an electron-positron pair is presented here. The results indicate that the peak value of the differential decay rate is reduced by about $50 \%$, because of soft-photon radiation. The number of $e^{+}e^{-}$ pairs having invariant masses in an energy bin of 0.5 MeV centered around $m_π$ is found to be about $20 \%$ smaller than the one it would be if radiative corrections were neglected.

hep-ph↗

arXiv1992

Technicolor Enhancement of $t \bar{t}$ Production at TeV-Colliders

It is shown that a technicolor theory containing a color-octet technipion, usually denoted by $P^{0'}_{8}$, will give rise to an enhancement of $t \bar t$ production at the Tevatron, LHC and SSC, via the process $gg \rightarrow P^{0'}_{8} \rightarrow t \bar t$. The relevant cross-sections are computed taking into account the large lower bound on the top mass coming from the "top search" experiments at LEP and CDF. At the LHC and SSC, the signal is found to be comparable to the QCD background, making the process quite accesible.

hep-ph↗