Publications (75)
Sub-GeV dark matter as pseudo-Goldstone from the seesaw scale
Michele Frigerio, Thomas Hambye, Eduard Masso
Pseudo Nambu-Goldstone bosons (pNGBs) are naturally light spin-zero particles, which can be interesting dark matter (DM) candidates. We study the phenomenology of a pNGB theta asso…
Relations among neutrino observables in the light of a large theta_13 angle
Xiaoyong Chu, Mikael Dhen, Thomas Hambye
The recent T2K and MINOS indications for a "large" theta_13 neutrino mixing angle can be accommodated in principle by an infinite number of Yukawa flavour structures in the seesaw…
Keeping It Renormalizable: Minimal Baryogenesis induced Asymmetric Dark Matter
Miguel Escudero, Thomas Hambye, Chandan Hati
Many asymmetric dark matter scenarios have been proposed to date. Among them, perhaps the most motivated ones are those in which the dark matter asymmetry is induced from the baryo…
Photo- and Hadrodisintegration constraints on massive relics decaying into neutrinos
Sara Bianco, Paul Frederik Depta, Jonas Frerick +3
We perform a detailed study of the cosmological constraints on the decay of a relic particle into neutrinos, , in particular those arising from the obs…
Higgs doublet decay as the origin of the baryon asymmetry
Thomas Hambye, Daniele Teresi
We consider a question which curiously had not been properly considered so far: in the standard seesaw model what is the minimum value the mass of a right-handed (RH) neutrino must…
Scalar triplet flavored leptogenesis: a systematic approach
D. Aristizabal Sierra, Mikael Dhen, Thomas Hambye
Type-II seesaw is a simple scenario in which Majorana neutrino masses are generated by the exchange of a heavy scalar electroweak triplet. When endowed with additional heavy fields…
Proton decay into charged leptons
Thomas Hambye, Julian Heeck
We discuss proton and neutron decays involving three leptons in the final state. Some of these modes could constitute the dominant decay channel because they conserve lepton-flavor…
Leptogenesis from R parity nonconservation
Thomas Hambye, Ernest Ma, Utpal Sarkar
It is known that realistic neutrino masses for neutrino oscillations may be obtained from R parity nonconserving supersymmetry. It is also known that such interactions would erase…
A Clockwork WIMP
Thomas Hambye, Daniele Teresi, Michel H. G. Tytgat
We embed a thermal dark matter (DM) candidate within the clockwork framework. This mechanism allows to stabilize the DM particle over cosmological time because it suppresses its de…
Emanations of Dark Matter: Muon Anomalous Magnetic Moment, Radiative Neutrino Mass, and Novel Leptogenesis at the TeV Scale
Thomas Hambye, Kristjan Kannike, Ernest Ma +1
The evidence for dark matter signals a new class of particles at the TeV scale, which may manifest themselves indirectly through loop effects. In a simple model we show that these…
Minimal self-interacting dark matter models with light mediator
Thomas Hambye, Laurent Vanderheyden
The light mediator scenario of self-interacting dark matter is strongly constrained in many ways. After summarizing the various constraints, we discuss minimal options and models w…
Supersymmetric Triplet Higgs Model of Neutrino Masses and Leptogenesis
Thomas Hambye, Ernest Ma, Utpal Sarkar
We construct a supersymmetric version of the triplet Higgs model for neutrino masses, which can generate a baryon asymmetry of the Universe through lepton-number violation and is c…
Leptogenesis from Neutralino Decay with Nonholomorphic R-Parity Violation
Thomas Hambye, Ernest Ma, Utpal Sarkar
In supersymmetric models with lepton-number violation, hence also R-parity violation, it is easy to have realistic neutrino masses, but then leptogenesis becomes difficult to achie…
Electroweak Symmetry Breaking induced by Dark Matter
Thomas Hambye, Michel H. G. Tytgat
The mechanism behind Electroweak Symmetry Breaking (EWSB) and the nature of dark matter (DM) are currently among the most important issues in high energy physics. Since a natural d…
Leptogenesis: beyond the minimal type I seesaw scenario
Thomas Hambye
Numerous recent evidences for neutrino masses have established the leptogenesis mechanism as a very natural possible explanation for the baryon asymmetry of the Universe. The expli…
Allowable Low-Energy E_6 Subgroups from Leptogenesis
Thomas Hambye, Ernest Ma, Martti Raidal +1
There are only two viable low-energy subgroups: or , whi…
The KM3NeT event: a primordial high energy neutrino?
Nicolas Grimbaum Yamamoto, Thomas Hambye
High energy neutrinos can be injected in the early Universe from the decay or annihilation of long lived primordial relics. We analyse the possibility that the ultrahigh energy neu…
SM Higgs mass bounds from theory
Thomas Hambye, Kurt Riesselmann
The two-loop Higgs mass upper bounds are reanalyzed. Previous results for a cutoff scale few TeV are found to be too stringent. For GeV we find $M_H < 180…
Neutrino lines from DM decay induced by high-scale seesaw interactions
Rupert Coy, Thomas Hambye
If the stability of the dark matter (DM) particle is due to an accidental symmetry, nothing prevents UV physics from destabilising it by inducing DM decays suppressed by powers of…
What if Dark Matter Gamma-Ray Lines come with Gluon Lines?
Xiaoyong Chu, Thomas Hambye, Tiziana Scarna +1
In dark matter (DM) models, the production of a gamma line (or of a "box-shaped" gamma-ray spectrum) from DM annihilation proceeds in general from a loop diagram involving a heavy…
Efficiency and maximal CP-asymmetry of scalar triplet leptogenesis
Thomas Hambye, Martti Raidal, Alessandro Strumia
We study thermal leptogenesis induced by decays of a scalar SU(2)_L triplet. Despite the presence of gauge interactions, unexpected features of the Boltzmann equations make the eff…
Dark matter electromagnetic dipoles: the WIMP expectation
Thomas Hambye, Xun-Jie Xu
We perform a systematic study of the electric and magnetic dipole moments of dark matter (DM) that are induced at the one-loop level when DM experiences four-fermion interactions w…
Four-point functions and kaon decays in a minimal AdS/QCD model
Thomas Hambye, Babiker Hassanain, John March-Russell +1
We study the predictions of holographic QCD for various observable four-point quark flavour current-current correlators. The dual 5-dimensional bulk theory we consider is a $SU(3)_…
Dark matter stability and unification without supersymmetry
Michele Frigerio, Thomas Hambye
In the absence of low energy supersymmetry, we show that (a) the dark matter particle alone at the TeV scale can improve gauge coupling unification, raising the unification scale u…
Gamma ray tests of Minimal Dark Matter
Marco Cirelli, Thomas Hambye, Paolo Panci +2
We reconsider the model of Minimal Dark Matter (a fermionic, hypercharge-less quintuplet of the EW interactions) and compute its gamma ray signatures. We compare them with a number…
SO(10) paths to dark matter
Sacha Ferrari, Thomas Hambye, Julian Heeck +1
The grand-unification gauge group SO(10) contains matter parity as a discrete subgroup. This symmetry could be at the origin of dark matter stability. The properties of the dark ma…
Confined hidden vector dark matter
Thomas Hambye, Michel H. G. Tytgat
We argue that the lightest vector bound states of a confining hidden sector communicating with the Standard Model through the Higgs portal are stable and are viable candidates of d…
Tests of Leptogenesis at Low Energy
Thomas Hambye
The problem of testing leptogenesis from low energy experiments is discussed following three different perspectives. Firstly, we review the prospects that from low energy experimen…
Muon conversion to electron in nuclei in type-I seesaw models
Rodrigo Alonso, Mikael Dhen, Belen Gavela +1
We compute the muon to electron conversion in the type-I seesaw model, as a function of the right-handed neutrino mixings and masses. The results are compared with previous computa…
The domain of thermal dark matter candidates
Rupert Coy, Thomas Hambye, Michel H. G. Tytgat +1
We consider, in general terms, the possible parameter space of thermal dark matter candidates. We assume that the dark matter particle is fundamental and was in thermal equilibrium…
Dynamical generation of the weak and Dark Matter scale
Thomas Hambye, Alessandro Strumia
Assuming that naturalness should be modified by ignoring quadratic divergences, we propose a simple extension of the Standard Model where the weak scale is dynamically generated to…
The Simplest Dark Matter Model at the Edge of Perturbativity
Miguel Escudero, Thomas Hambye
Increasingly sensitive direct detection dark matter experiments are testing important regions of parameter space for WIMP dark matter and pushing many models to the multi-TeV regim…
Baryogenesis from L-violating Higgs-doublet decay in the density-matrix formalism
Thomas Hambye, Daniele Teresi
We compute in the density-matrix formalism the baryon asymmetry generated by the decay of the Higgs doublet into a right-handed (RH) neutrino and a Standard Model lepton. The empha…
New Search for Monochromatic Neutrinos from Dark Matter Decay
Chaïmae El Aisati, Michael Gustafsson, Thomas Hambye
From data recently reported from the IceCube telescope, we derive new bounds on the monochromatic neutrino signal produced from dark matter particle decays. In the few TeV to tens…
TeV scale resonant leptogenesis from supersymmetry breaking
Thomas Hambye, John March-Russell, Stephen M. West
We propose a model of TeV-scale resonant leptogenesis based upon recent models of the generation of light neutrino masses from supersymmetry-breaking effects with TeV-scale right-h…
Various realizations of leptogenesis and neutrino mass constraints
Thomas Hambye
Seven types of leptogenesis models which can lead to a successful explanation of baryogenesis are presented. Emphasis is put on the conditions which need to be fulfilled by the neu…
Predictions of Physical Observables from Minimal Neutrino Structures
Thomas Hambye
We find all possible seesaw textures which can describe in a natural way the currently observed neutrino oscillation pattern in terms of a minimum number of parameters. Natural her…
Inert Scalar Doublet Asymmetry as Origin of Dark Matter
Mikael Dhen, Thomas Hambye
In the inert scalar doublet framework, we analyze what would be the effect of a asymmetry that could have been produced in the Universe thermal bath at high temperature. We s…
Production Regimes for Self-Interacting Dark Matter
Nicolas Bernal, Xiaoyong Chu, Camilo Garcia-Cely +2
In the context of Self-Interacting Dark Matter as a solution for the small-scale structure problems, we consider the possibility that Dark Matter could have been produced without b…
Intense Gamma-Ray Lines from Hidden Vector Dark Matter Decay
Chiara Arina, Thomas Hambye, Alejandro Ibarra +1
Scenarios with hidden, spontaneously broken, non-abelian gauge groups contain a natural dark matter candidate, the hidden vector, whose longevity is due to an accidental custodial…
Hidden vector dark matter
Thomas Hambye
We show that dark matter could be made of massive gauge bosons whose stability doesn't require to impose by hand any discrete or global symmetry. Stability of gauge bosons can be g…
Effective Theory of Dark Matter Decay into Monochromatic Photons and its Implications: Constraints from Associated Cosmic-Ray Emission
Michael Gustafsson, Thomas Hambye, Tiziana Scarna
We show that there exists only a quite limited number of higher dimensional operators which can naturally lead to a slow decay of dark matter particles into monochromatic photons.…
A facility to Search for Hidden Particles at the CERN SPS: the SHiP physics case
Sergey Alekhin, Wolfgang Altmannshofer, Takehiko Asaka +82
This paper describes the physics case for a new fixed target facility at CERN SPS. The SHiP (Search for Hidden Particles) experiment is intended to hunt for new physics in the larg…
Reconciling leptogenesis with observable mu --> e gamma rates
Steve Blanchet, Thomas Hambye, Francois-Xavier Josse-Michaux
We perform a detailed analysis of thermal leptogenesis in the framework of seesaw models which approximately conserve lepton number. These models are known to allow for large Yukaw…
Can the relic density of self-interacting dark matter be due to annihilations into Standard Model particles?
Xiaoyong Chu, Camilo Garcia-Cely, Thomas Hambye
Motivated by the hypothesis that dark matter self-interactions provide a solution to the small-scale structure formation problems, we investigate the possibilities that the relic d…
Natural relations among physical observables in the neutrino mass matrix
Riccardo Barbieri, Thomas Hambye, Andrea Romanino
We find all possible relations among physical observables arising from neutrino mass matrices that describe in a natural way the currently observed pattern (tan_23 and tan_12 large…
Super-cool Dark Matter
Thomas Hambye, Alessandro Strumia, Daniele Teresi
In dimension-less theories of dynamical generation of the weak scale, the Universe can undergo a period of low-scale inflation during which all particles are massless and super-coo…
Symmetry breaking induced by top quark loops from a model without scalar mass
Thomas Hambye
Considering the standard model as an effective electroweak theory, in which we have no scalar mass term in the Higgs potential , we show that the spontaneous symmetry bre…
Leptogenesis from right-handed neutrino decays to right-handed leptons
Thomas Hambye
We investigate what would be the consequences for leptogenesis of the existence of a charged SU(2)_L singlet scalar delta^+. If such a scalar particle exists, it allows the right-h…
Cosmological constraints on the decay of heavy relics into neutrinos
Thomas Hambye, Marco Hufnagel, Matteo Lucca
A massive particle decaying into neutrinos in the early Universe is known to be less constrained than if it was decaying into other standard model particles. However, even if the d…
Charged lepton flavor violation and the origin of neutrino masses
Thomas Hambye
The neutrino oscillations imply that charged lepton flavor violation (CLFV) processes do exist. Even if the associated rates are in general expected very suppressed, it turns out t…
Seesaw determination of the dark matter relic density
Rupert Coy, Aritra Gupta, Thomas Hambye
In this article, we show that in the usual type-I seesaw framework, augmented solely by a neutrino portal interaction, the dark matter (DM) relic density can be created through fre…
Matching conditions and Higgs mass upper bounds revisited
Thomas Hambye, Kurt Riesselmann
Matching conditions relate couplings to particle masses. We discuss the importance of one-loop matching conditions in Higgs and top-quark sector as well as the choice of the matchi…
Dark Matter Decay to a Photon and a Neutrino: the Double Monochromatic Smoking Gun Scenario
Chaïmae El Aisati, Michael Gustafsson, Thomas Hambye +1
In the energy range from few TeV to 25 TeV, upper bounds on the dark matter decay rate into high energy monochromatic neutrinos have recently become comparable to those on monochro…
Primordial high energy neutrinos: theoretical/observational constraints and sharp spectral features
Nicolas Grimbaum Yamamoto, Thomas Hambye
Among the few ways that allow or could allow us to probe the early Universe from the observation of a flux of primordial particles, there is one possibility which has been little s…
A light scalar WIMP through the Higgs portal and CoGeNT
Sarah Andreas, Chiara Arina, Thomas Hambye +2
If dark matter (DM) simply consists in a scalar particle interacting dominantly with the Higgs boson, the ratio of its annihilation cross section ---which is relevant both for the…
Dark matter from the centre of SU(N)
Michele Frigerio, Nicolas Grimbaum-Yamamoto, Thomas Hambye
A dark sector with non-abelian gauge symmetry provides a sound framework to justify stable dark matter (DM) candidates. We consider scalar fields charged under a gauge grou…
New Analysis of Neutron Star Constraints on Asymmetric Dark Matter
Raghuveer Garani, Yoann Genolini, Thomas Hambye
Due to their extreme density and low temperature, neutron stars (NS) are efficient probes to unveil interactions between standard model and dark matter (DM) particles. From elastic…
Dark matter bound-state formation in the Sun
Xiaoyong Chu, Raghuveer Garani, Camilo GarcÃa-Cely +1
The Sun may capture asymmetric dark matter (DM), which can subsequently form bound-states through the radiative emission of a sub-GeV scalar. This process enables generation of sca…
Accidentally light scalars from large representations
Felix Brümmer, Giacomo Ferrante, Michele Frigerio +1
In models with spontaneous symmetry breaking by scalar fields in large group representations, we observe that some of the scalar masses can be loop-suppressed with respect to the n…
Right-Handed Sector Leptogenesis
Michele Frigerio, Thomas Hambye, Ernest Ma
Instead of creating the observed baryon asymmetry of the universe by the decay of right-handed (RH) neutrinos to left-handed leptons, we propose to generate it dominantly by the de…
Constraints on neutrino masses from leptogenesis models
Thomas Hambye, Yin Lin, Alessio Notari +2
Upper bounds on the CP asymmetry relevant for leptogenesis are reexamined and found weaker than in previous literature, both for hierarchical and for quasi-degenerate right-handed…
Can a millicharged dark matter particle emit an observable gamma-ray line?
Chaïmae El Aisati, Thomas Hambye, Tiziana Scarna
If a gamma-ray line is observed in the near future, it will be important to determine what kind of dark matter (DM) particle could be at its origin. We investigate the possibility…
Consequences of Triplet Seesaw for Leptogenesis
Thomas Hambye, Goran Senjanovic
We present the various leptogenesis scenarios which may occur if, in addition to the ordinary heavy right-handed neutrinos, there exists a heavy scalar SU(2)_L triplet coupled to l…
Prospects for discovering a neutrino line induced by dark matter annihilation
Chaimae El Aisati, Camilo Garcia-Cely, Thomas Hambye +1
In the near future, neutrino telescopes are expected to improve their sensitivity to the flux of monochromatic neutrinos produced by dark matter (DM) in our galaxy. This is illustr…
The Four Basic Ways of Creating Dark Matter Through a Portal
Xiaoyong Chu, Thomas Hambye, Michel H. G. Tytgat
We consider the possibility that along the thermal history of the Universe, dark matter (DM) would have been created from Standard Model particles, either through a kinetic mixing…
Dark matter from dark photons: a taxonomy of dark matter production
Thomas Hambye, Michel H. G. Tytgat, Jérôme Vandecasteele +1
We analyse how dark matter (DM) can be produced in the early universe, working in the framework of a hidden sector charged under a U(1)' gauge symmetry and interacting with the Sta…
Direct Detection is testing Freeze-in
Thomas Hambye, Michel H. G. Tytgat, Jérôme Vandecasteele +1
Dark Matter (DM) may belong to a hidden sector that is only feebly interacting with the Standard Model (SM) and may have never been in thermal equilibrium in the Early Universe. In…
Leptogenesis at the TeV scale
Thomas Hambye
We present a general description of the problems encountered when attempting to build a simple model of leptogenesis and hence of baryogenesis at an energy scale as low as 1-10 TeV…
Neutrino mass matrix solutions and neutrinoless double beta decay
Thomas Hambye
We present a determination of the neutrino mass matrix which holds for values of the neutrinoless double beta decay effective mass m_{ee} larger than the neutrino mass differences.…
On the Delta I = 1/2 Rule in Holographic QCD
Thomas Hambye, Babiker Hassanain, John March-Russell +1
We study the rule for kaon decays and the parameter for mixing in a dual 5-dimensional holographic QCD model. We perform, in the chiral limit,…
WIMP dark matter, Higgs exchange and DAMA
Sarah Andreas, Thomas Hambye, Michel H. G. Tytgat
In the WIMP scenario, there is a one-to-one relation between the dark matter (DM) relic density and spin independent direct detection rate if both the annihilation of DM and its el…
Dark matter as a heavy thermal hot relic
Thomas Hambye, Matteo Lucca, Laurent Vanderheyden
If, during the early Universe epoch, the dark matter particle thermalizes in a hidden sector which does not thermalize with the Standard Model thermal bath, its relativistic therma…
Type-III see-saw at LHC
Roberto Franceschini, Thomas Hambye, Alessandro Strumia
Neutrino masses can be generated by fermion triplets with TeV-scale mass, that would manifest at LHC as production of two leptons together with two heavy SM vectors or higgs, givin…
On the stability of particle dark matter
Thomas Hambye
From the particle physics point of view, the most peculiar property of the dark matter particle is its stability on cosmological time scales. We briefly review the possible origins…