Sinn der Bilder

We study the impact of TeV-scale sterile neutrinos on electro-weak precision observables and lepton number and flavour violating decays in the framework of a type-I see-saw extension of the Standard Model. At tree level sterile neutrinos manifest themselves via non-unitarity of the PMNS matrix and at one-loop level they modify the oblique radiative corrections. We derive explicit formulae for the S, T, U parameters in terms of the neutrino masses and mixings and perform a numerical fit to the electro-weak observables. We find regions of parameter space with a sizable active-sterile mixing which provide a better over-all fit compared to the case where the mixing is negligible. Specifically we find improvements of the invisible Z-decay width, the charged-to-neutralcurrent ratio for neutrino scattering experiments and of the deviation of the W boson mass from the theoretical expectation.

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“…In terms of the twocomponent spinors the four-component Dirac spinor and its Dirac-conjugate read [80]:…”

Section: Appendix A: Oblique Correctionsmentioning

confidence: 99%

Improving electro-weak fits with TeV-scale sterile neutrinos

Akhmedov

Kartavtsev

Lindner

et al. 2013

J. High Energ. Phys.

105

170

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“…Integrating ( 9) and ( 12) over t and neglecting the effective masses of the initial and final lepton and quarks we obtain the standard expressions (see, e.g. [39,40]) for the reduced cross-sections of the Higgs-mediated scattering processes:…”

Section: Rate Equationsmentioning

confidence: 99%

Systematic approach to thermal leptogenesis

et al. 2013

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In this work we study the contribution to leptogenesis from ∆L = 1 decay and scattering processes mediated by the Higgs with quarks in the initial and final states using the formalism of non-equilibrium quantum field theory. Starting from fundamental equations for correlators of the quantum fields we derive quantum-corrected Boltzmann and rate equations for the total lepton asymmetry improved in that they include quantum-statistical effects and medium corrections to the quasiparticle properties. To compute the collision term we take into account one-and two-loop contributions to the lepton self-energy and use the extended quasiparticle approximation for the Higgs two-point function. The resulting CP-violating and washout reaction densities are numerically compared to the conventional ones.

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“…Since B − L is gauged, the Majorana mass of the right-handed neutrino, which is an essential ingredient of leptogenesis, is forbidden unless B − L symmetry is broken down. Present data on neutrino masses as well as theoretical estimates of leptogenesis in other GUT models favour the 10 10 -10 12 GeV ν c mass range [8,13].…”

Section: Particle Content and Charge Assignmentsmentioning

confidence: 65%

Breaking ofB−Lin superstring inspiredE₆model

Kartavtsev¹

2005

J. Phys. G: Nucl. Part. Phys.

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Abstract. In the framework of the superstring inspired E 6 model, 'low-energy' extensions of the standard model compatible with leptogenesis are considered and masses of right-handed neutrinos in two scenarios allowed by long-lived protons are discussed. The presence of two additional generations allows breaking of B − L without generating nonzero vacuum expectation values of right-handed sneutrinos of the three known generations. After the symmetry breaking, right-handed neutrinos acquire Majorana masses M ν c ≃ 10 11 GeV. Within the framework of a simple discrete symmetry, assumptions made to provide a large mass of right-handed neutrinos are shown to be self-consistent. Supersymmetric structure of the theory ensures that large corrections, associated with the presence of a (super)heavy gauge field, cancel out.Breaking of B − L in superstring inspired E 6 model.

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Sinn der Bilder

Cited by 6 publications

References 2 publications

Improving electro-weak fits with TeV-scale sterile neutrinos

Improving electro-weak fits with TeV-scale sterile neutrinos

Systematic approach to thermal leptogenesis

Breaking ofB−Lin superstring inspiredE₆model

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Sinn der Bilder

Cited by 6 publications

References 2 publications

Improving electro-weak fits with TeV-scale sterile neutrinos

Improving electro-weak fits with TeV-scale sterile neutrinos

Systematic approach to thermal leptogenesis

Breaking ofB−Lin superstring inspiredE6model

Contact Info

Product

Resources

About

Breaking ofB−Lin superstring inspiredE₆model