Björn Garbrecht

Technical University of Munich

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Marco Drewes

UCLouvain

Wen-Yuan Ai

King's College London

Juraj Klarić

UCLouvain

Carlos Tamarit

Johannes Gutenberg University Mainz

Dario Gueter

Max Planck Institute for Physics

Tomislav Prokopec

Utrecht University

Peter Millington

University of Manchester

Juan S. Cruz

Centre for Cosmology and Particle Physics Phenomenology

Richard A. Battye

University of Manchester

Thomas Konstandin

Deutsches Elektronen-Synchrotron DESY

Cooperative Institutions

European Organization for Nuclear Research

Technical University of Munich

Fermi National Accelerator Laboratory

Centre National de la Recherche Scientifique

Deutsches Elektronen-Synchrotron DESY

Perimeter Institute

Universidad Autónoma de Madrid

University of Manchester

École Polytechnique Fédérale de Lausanne

Max Planck Institute for Physics

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Probing the Seesaw Mechanism and Leptogenesis with the International Linear Collider

arXiv (Cornell University) (2018)

Stefan Antusch Eros Cazzato Marco Drewes Oliver Fischer Björn Garbrecht

We investigate the potential of the International Linear Collider (ILC) to probe the mechanisms of neutrino mass generation and leptogenesis within the minimal seesaw model. Our results can also be used as an estimate for the potential of a Compact Linear Collider (CLIC). We find that heavy sterile neutrinos that simultaneously explain both, the observed light neutrino oscillations and the baryon asymmetry of the universe, can be found in displaced vertex searches at ILC. We further study the precision at which the flavour-dependent active-sterile mixing angles can be measured. The measurement of the ratios of these mixing angles, and potentially also of the heavy neutrino mass splitting, can test whether minimal type I seesaw models are the origin of the light neutrino masses, and it can be a first step towards probing leptogenesis as the mechanism of baryogenesis. Our results show that the ILC can be used as a discovery machine for New Physics in feebly coupled sectors that can address fundamental questions in particle physics and cosmology.

Leptogenesis

Seesaw mechanism

10.48550/arxiv.1801.06534

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Low Scale Leptogenesis from Non-Leptonic CP-Phases

arXiv (Cornell University) (2009)

Daniel J. H. Chung Björn Garbrecht Michael J. Ramsey-Musolf

This paper has been withdrawn by the authors.

Leptogenesis

10.48550/arxiv.0904.1591

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Citations (1)

Superradiance in Stars: Non-equilibrium approach to damping of fields in stellar media

arXiv (Cornell University) (2022)

Francesca Chadha-Day Björn Garbrecht J. D. McDonald

Superradiance in black holes is well-understood but a general treatment for superradiance in stars has until now been lacking. This is surprising given the ease with which we can observe isolated neutron stars and the array of signatures which would result from stellar superradiance. In this work, we present the first systematic pipeline for computing superradiance rates in rotating stars. Our method can be used with any Lagrangian describing the interaction between the superradiant field and the constituents of the star. Our scheme falls into two parts: firstly we show how field theory at finite density can be used to express the absorption of long wavelength modes into the star in terms of microphsyical scattering processes. This allows us to derive a damped equation of motion for the bosonic field. We then feed this into an effective theory for long wavelengths (the so-called worldline formalism) to describe the amplification of superradiant modes of arbitrary multipole moment for a rapidly rotating star. Our method places stellar superradiance on a firm theoretical footing and allows the calculation of the superradiance rate arising from any interaction between a bosonic field and stellar matter.

Superradiance

10.48550/arxiv.2207.07662

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Leptogenesis: Improving predictions for experimental searches

Proceedings of The 39th International Conference on High Energy Physics — PoS(ICHEP2018) (2017)

Marco Drewes Björn Garbrecht Dario Gueter Juraj Klarić

Heavy right handed neutrinos could not only explain the observed neutrino masses via the seesaw mechanism, but also generate the baryon asymmetry of the universe via leptogenesis due to their CP-violating interactions in the early universe. We review recent progress in the theoretical description of this nonequilibrium process. Improved calculations are particularly important for a comparison with experimental data in testable scenarios with Majorana masses below the TeV scale, in which the heavy neutrinos can be found at the LHC, in the NA62 experiment, at T2K or in future experiments, including SHiP, DUNE and experiments at the FCC, ILC or CEPC. In addition, the relevant source of CP-violation may be experimentally accessible, and the heavy neutrinos can give a sizable contribution to neutrinoless double $\beta$ decay. In these low scale leptogenesis scenarios, the matter-antimatter asymmetry is generated at temperatures when the heavy neutrinos are relativistic, and thermal corrections to the transport equations in the early universe are large.

Leptogenesis

Baryon asymmetry

10.22323/1.282.0514

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Citations (1)

Erratum to: “Quantum corrections to the Reissner–Nordström and Kerr–Newman metrics” [Phys. Lett. B 529 (2002) 132]

Physics Letters B (2005)

John F. Donoghue Barry R. Holstein Björn Garbrecht Thomas Konstandin

10.1016/j.physletb.2005.03.018

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Citations (18)

Quantum corrections to the Reissner-Nordstrom and Kerr-Newman metrics (vol 529, pg 132, 2002)

Physics Letters B (2005)

JF Donoghue BR Holstein Björn Garbrecht Thomas Konstandin

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Leptogenesis from oscillations of heavy neutrinos with large mixing angles

Journal of High Energy Physics (2016)

Marco Drewes Björn Garbrecht Dario Gueter Juraj Klarić

The extension of the Standard Model by heavy right-handed neutrinos can simultaneously explain the observed neutrino masses via the seesaw mechanism and the baryon asymmetry of the Universe via leptogenesis. If the mass of the heavy neutrinos is below the electroweak scale, they may be found at the LHC, BELLE II, NA62, the proposed SHiP experiment or a future high-energy collider. In this mass range, the baryon asymmetry is generated via CP-violating oscillations of the heavy neutrinos during their production. We study the generation of the baryon asymmetry of the Universe in this scenario from first principles of non-equilibrium quantum field theory,including spectator processes and feedback effects. We eliminate several uncertainties from previous calculations and find that the baryon asymmetry of the Universe can be explained with larger heavy neutrino mixing angles, increasing the chance for an experimental discovery. For the limiting cases of fast and strongly overdamped oscillations of right-handed neutrinos, the generation of the baryon asymmetry can be calculated analytically up to corrections of order one.

Leptogenesis

Baryon asymmetry

Electroweak scale

Seesaw mechanism

10.1007/jhep12(2016)150

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Citations (70)

Phenomenology of baryogenesis from lepton-doublet mixing

Nuclear Physics B (2015)

Björn Garbrecht Ignacio Izaguirre

Mixing lepton doublets of the Standard Model can lead to lepton flavour asymmetries in the Early Universe. We present a diagrammatic representation of this recently identified source of CP violation and elaborate in detail on the correlations between the lepton flavours at different temperatures. For a model where two sterile right-handed neutrinos generate the light neutrino masses through the see-saw mechanism, the lower bound on reheat temperatures in accordance with the observed baryon asymmetry turns out to be ≳1.2×109 GeV. With three right-handed neutrinos, substantially smaller values are viable. This requires however a tuning of the Yukawa couplings, such that there are cancellations between the individual contributions to the masses of the light neutrinos.

Leptogenesis

Yukawa potential

Baryon asymmetry

CP violation

Lepton number

10.1016/j.nuclphysb.2015.04.017

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Citations (3)

Probing the seesaw mechanism and leptogenesis with the international linear collider

Stefan Antusch Eros Cazzato Marco Drewes Oliver Fischer Björn Garbrecht

Leptogenesis

Seesaw mechanism