Browsing by Author "Tandean, Jusak"

Now showing 1 - 4 of 4

Constraining nonstandard neutrino-electron interactions due to a new light spin-1 boson
(SPRINGER, 2013) Chiang, Cheng-Wei; Faisel, Gaber; Lin, Yi-Fan; Tandean, Jusak
We consider nonstandard interactions of neutrinos with electrons arising from a new light spin-1 particle with mass of tens of GeV or lower and couplings to the neutrinos and electron. This boson is not necessarily a gauge boson and is assumed to have no mixing with standard-model gauge bosons. Adopting a model-independent approach, we study constraints on the flavor-conserving and -violating couplings of the boson with the leptons from a number of experimental data. Specifically, we take into account the (anti)neutrino-electron scattering and e(+)e(-) -> nu(nu) over bar gamma measurements and keep explicitly the dependence on the new particle mass in all calculations. We find that one of the two sets of data can provide the stronger constraints, depending on the mass and width of the boson. Also, we evaluate complementary constraints on its separate flavor-conserving couplings to the electron and neutrinos from other latest experimental results.
Effects of two inert scalar doublets on Higgs boson interactions and the electroweak phase transition
(AMER PHYSICAL SOC, 2015) Ahriche, Amine; Faisel, Gaber; Ho, Shu-Yu; Nasri, Salah; Tandean, Jusak
We study some implications of the presence of two new scalar weak doublets beyond the standard model which have zero vacuum expectation values and are charged under an extra Abelian gauge symmetry. The additional gauge sector does not couple directly to standard-model particles. We investigate specifically the effects of the scalars on oblique electroweak parameters and on the interactions of the 125 GeV Higgs boson, especially its decay modes h --> gamma gamma, gamma Z and trilinear self-coupling, all of which will be probed with improved precision in future Higgs measurements. Moreover, we explore how the new scalars may give rise to strongly first-order electroweak phase transition and also show its correlation with sizable modifications to the Higgs trilinear self-coupling.
Exploring high-mass diphoton resonance without new colored states
(ELSEVIER SCIENCE BV, 2017) Ahriche, Amine; Faisel, Gaber; Nasri, Salah; Tandean, Jusak
A new heavy resonance may be observable at the LHC if it has a significant decay branching fraction into a pair of photons. We entertain this possibility by looking at the modest excess in the diphoton invariant mass spectrum around 750 GeV recently reported in the ATLAS and CMS experiments. Assuming that it is a spinless boson, dubbed (s) over tilde, we consider it within a model containing two weak scalar doublets having zero vacuum expectation values and a scalar singlet in addition to the doublet responsible for breaking the electroweak symmetry. The model also possesses three Dirac neutral singlet fermions, the lightest one of which can play the role of dark matter and which participate with the new doublet scalars in generating light neutrino masses radiatively. We show that the model is consistent with all phenomenological constraints and can yield a production cross section sigma (pp -> (s) over tilde -> gamma gamma) of roughly the desired size, mainly via the photon-fusion contribution, without involving extra colored fermions or bosons. We also discuss other major decay modes of (s) over tilde which are potentially testable in upcoming LHC measurements. (C) 2017 The Author(s). Published by Elsevier B.V.
Exploring X-ray lines as scotogenic signals
(ELSEVIER, 2014) Faisel, Gaber; Ho, Shu-Yu; Tandean, Jusak
We consider some implications of X-ray lines from certain astronomical objects as potential effects of dark matter decay in the context of the scotogenic model, where neutrinos acquire mass radiatively via one-loop interactions with dark matter. As an example, we focus on the 3.5 keV line recently detected in the X-ray spectra of galaxy clusters, assuming that it stands future scrutiny. We explore the scenario in which the line originates from the slow decay of fermionic dark matter in the model. After obtaining anumber of benchmark points representing the parameter space consistent with the new data and various other constraints, we make predictions on several observables in leptonic processes. They include the effective Majorana mass in neutrinoless double-beta decay, the sum of neutrino masses, and the rate of flavor-changing decay mu -> e gamma, as well as the cross sections of e(+)e(-) collisions into final states containing nonstandard particles in the model. These are testable in ongoing or future experiments and thus offer means to probe the scotogenic scenario studied. (C) 2014 The Authors. Published by Elsevier B. V. This is an open access article under the CC BY license (http://creativecommons. org/licenses/by/3.0/). Funded by SCOAP(3).