arXiv subjects

D. T. Papadamou

Publications and source records attributed to D. T. Papadamou.

6 recordsLinked to original sources

arXiv2002

Manifestations of Extra Dimensions in a Neutrino Telescope

Theories with large extra dimensions provide the possibility that a flavor neutrino, localized in a 3+1 brane, can mix with a singlet neutrino living in the bulk. This mixing leads to unconventional patterns of neutrino matter oscillations and we examine in details how these oscillations depend upon two parameters: the brane-bulk coupling $ξ$ and the effective mass $μ$ of the flavor neutrino inside matter. We find that high energy $(E \ge 50$ GeV) $ν_μ$ neutrinos, to be detected by neutrino telescopes, can give signals of extra dimensions. With a 1 k$m^{3}$ neutrino telescope extra dimensions with radius down to $1μm$ can be tested directly, while for smaller radius an indirect evidence can be established.

hep-ph↗

arXiv1998

New Physics Signatures in Dijets at Hadron Colliders

We show how to detect and disentangle at the upgraded Tevatron and at LHC, the effects of the three purely gluonic $dim=6$ $SU(3)\times SU(2) \times U(1)$ CP-conserving and CP-violating gauge invariant operators $\olØ_{DG}$, $Ø_G$ and $\wtilØ_{G}$. These operators are inevitably generated by New Physics (NP), if the heavy particles responsible for it are coloured. We establish the relations between their coupling constants and the corresponding NP scales defined through the unitarity relations. We then study the sensitivity and limits obtainable through production processes involving one or two jets, and express these limits in terms of the NP scales implied by unitarity. A detailed comparison with the results of the studies of the analogous electroweak operators, is also made.

hep-ph↗

arXiv1997

Tests of possible non standard properties of the heavy quarks and the Higgs boson

We discuss the sensitivity of the processes e+e- to b b(bar), e+e- to t t(bar) and gamma gamma to H to certain residual New Physics interactions affecting the heavy quark and Higgs boson sector. With a linear collider of 500 GeV, one should be able to detect and identify such effects with a characteristic scale up to 50 TeV.

hep-ph↗

arXiv1997

Using e-e+ to b b(bar) to test properties of new interactions at LEP2 and higher energies

We show that in e-e+ colliders at energies above the Z-peak, the process e-e+ to b b(bar) becomes very sensitive to the presence of residual New Physics (NP) effects described by the dim=6 SU(3)*SU(2)*U(1) gauge invariant operators O(qW), O(qB) and O(bB). This observation should be combined with the already known great sensitivity of the light fermion production through e-e+ annihilation above the Z-peak, to the bosonic operators O(DW) and O(DB). It is important to emphasize that the effects of all these operators are largely hidden at the Z-peak; while they are enhanced above it through the use the "Z-peak subtracted representation". The observability limits for detecting these operators at LEP2 and NLC, through such light fermion production processes, are also established.

hep-ph↗

arXiv1997

General description of New Physics in t, b and boson Interactions and its Unitarity Constraints

We list all possible dim=6 CP conserving and SU(3)* SU(2)*U(1) gauge invariant interactions, which could be generated in case no new particles would be reachable in the future Colliders, and the only observable New Physics would be in the form of new interactions affecting the scalar sector and the quarks of the third family. These interactions are described by operators involving the standard model scalar field, the quarks of the third family and the gauge bosons. Subsequently, we identify those operators which do not contribute to LEP1 (and lower energy) observables at tree level and are not purely gluonic. Since present measurements do not strongly constrain the couplings of these operators, we derive here the unitarity bounds on them. Finally, in order to get a feeling on the possible physical meaning of the appearance of any of these operators, we identify the operators generated in a class of renormalizable dynamical models which at the TeV scale, are fully described by the SU(3)*SU(2)*U(1) gauge group.

hep-ph↗

arXiv1996

Dynamical Scenarios for Anomalous Interactions involving t, b quarks and bosons

In the present paper we explore various dynamical scenarios for New Physics (NP) which could be generated by very heavy particles and observed in the form of non-standard "low energy" interactions affecting the scalar sector, the gauge bosons and the quarks of the third family. Such interactions have been previously expressed in terms of 48 CP-conserving gauge invariant operators. We show that each scenario is characterized by a specific subset of such operators. Thus, if some traces of NP are ever found in the experimental data, then the comparison with the predictions of the various scenarios, should be able to guide the search towards the underlying dynamics generating it.

hep-ph↗