Dr
kenji kadota
(Institute for Basic Science)
24/09/2014, 14:00
To illustrate the complementarity of the collider and astrophysics bounds on the light (MeV-scale mass) dark matter (DM), the constraints on the dipole DM from the ILC and supernova will be discussed, along with those from the LHC and solar data (helioseismology).
Leila Ali Cavasonza
(RWTH Aachen)
24/09/2014, 14:20
A very exciting challenge in particle and astroparticle physics is the exploration of the nature of dark matter. The striking evidences of the existence of dark matter
are also the strongest phenomenological indications for physics beyond the Standard Model.
A huge experimental effort is currently made at colliders and via astrophysical experiments to shed light on the nature of dark...
Mr
Francesco Dighera
(Technische Universitaet Muenchen)
24/09/2014, 14:40
There is an increasing interest in accurate dark matter relic density
predictions, which requires next-to-leading order (NLO) calculations.
The method applied up to now uses zero-temperature NLO calculations
of annihilation cross sections in the standard Boltzmann equation
for freeze-out, and is conceptually problematic, since it ignores the
finite-temperature infrared (IR)...
Ms
Francesca Day
(University of Oxford)
24/09/2014, 15:00
I describe a scenario in which the 3.55 keV photon line recently observed in galaxy clusters and Andromeda is caused by dark matter decay to axion like particles (ALPS), which then mix with the photon in astrophysical magnetic fields. This model is particularly well motivated by the observed morphology of the 3.55 keV flux. In particular, I describe predictions for Milky Way halo dark matter...
Rafael Alves Batista
(II. Institut für Theoretische Physik, Universität Hamburg)
24/09/2014, 15:20
The origin and nature of the ultra-high energy cosmic rays (UHECRs) are still unresolved issues. Ultra-high energy cosmic rays can propagate diffusively in cosmic magnetic fields. When their propagation time is comparable to the age of the universe a suppression of the flux compared to the case without magnetic fields is expected. In this work we parametrize this suppression for different...
Mr
Martin Vollmann
(Uni Hamburg)
24/09/2014, 16:10
Monochromatic gamma ray lines have long been known to provide potential smoking gun signals for annihilating dark matter. Here, we demonstrate that the situation is particularly interesting for Kaluza-Klein dark matter because resonant annihilation is generically expected for small, but not necessarily vanishing relative velocities of the annihilating particles. We calculate the contribution...
Mr
Geoff Beck
(University of the Witwatersrand)
24/09/2014, 16:25
Dark matter remains a major gap in the understanding of modern physics with many proposed
routes to direct and indirect detection. In this study we model the radio emission from neutralino annihilation in DM halos assuming various annihilation channels, a model of the magnetic field and an exploration of a range of redshifts. Using this model we provide estimates for the detectability of...
Dr
Ahmad Galea
(University of Oslo)
24/09/2014, 16:40
Models which have a dark matter candidate that is a Majorana fermion in most cases contain helicity suppressed annihilation processes. Notable examples of such a scenario are models for supersymmetric neutralino dark matter, in which annihilation into a fermion anti-fermion pair is p-wave suppressed. It is well known that the radiation of a gauge boson can lift helicity suppression, enhancing...
Mr
Andrew J. Powell
(University of Oxford)
24/09/2014, 16:55
Observations have revealed diffuse excess emission in a large number of galaxy clusters in the ~200 eV soft X-ray band: the Cluster Soft X-ray Excess. In this talk I will discuss how a primordially generated background of relativistic axion-like particles can explain this puzzling feature of galaxy cluster observations. Such a background is generically predicted to be produced from the decays...
Dr
Alexandre Payez
(DESY)
24/09/2014, 17:10
We revisit the limit on very light axion-like particles from the absence of coincidental gamma rays with the neutrino burst from SN1987A. This is done using updated supernova simulations, updated models for the magnetic field inside the Galaxy, and taking into account the effects of proton degeneracy and mass reduction on the production of these particles in the supernova core.
Dr
Aleksei Zaiats
(Department of General Relativity and Gravitation, Kazan Federal University)
24/09/2014, 17:25
In the framework of Einstein-Maxwell-Vlasov-axion model we
analyzed the dispersion relations for the perturbations in an
initially isotropic and homogeneous axionically active
ultrarelativistic plasma, which expands in the de Sitter-type
cosmological background, and classify the longitudinal and
transversal electromagnetic modes. We show that for the special
choice of the guiding model...
Dr
Saviano Ninetta
(IPPP, Durham University)
25/09/2014, 14:00
In the last recent years different anomalies observed in short-baseline neutrino
oscillation experiments seem to point towards the existence of light sterile neutrinos.
These sterile neutrinos can also be produced in the early universe by oscillations of the
active neutrinos and can affect different cosmological observables. In particular,
their properties can be constrained by their...
Daniel Boriero
(Bielefeld University)
25/09/2014, 14:20
In this talk will be presented how different processes may produce distortions in the Fermi-Dirac distribution of cosmological neutrinos and their effects on cosmological observables and parameters. Will be given attention to the standard model and minimum extensions.
Jasper Hasenkamp
(New York University)
25/09/2014, 14:40
Despite the astonishing success of standard ΛCDM cosmology, there is mounting evidence for a tension with observations at small and intermediate scales. We introduce a simple model where both, cold dark matter (DM) and sterile neutrinos, are charged under a new U(1)_X gauge interaction. The resulting DM self-interactions resolve the tension with the observed abundances and internal density...
Michael Duerr
(MPIK, Heidelberg)
25/09/2014, 15:00
I present extensions of the Standard Model, where the global symmetries baryon and lepton number are gauged and subsequently spontaneously broken. These theories are consistent with collider bounds and cosmology, and have intriguing consequences due to the requirement of anomaly cancellation: lepto-baryon fields that have to be introduced can be a dark matter candidate and/or generate neutrino...
Dr
Diaz Jorge S.
(Karlsruhe Institute of Technology)
25/09/2014, 15:20
Lorentz invariance is a cornerstone of modern physics. Deviations from exact symmetry would radically change our view of the universe and current experiments allow us to test the validity of this assumption. In this talk, I will describe how the recent observation of high-energy astrophysical neutrinos can be used to constrain violations of Lorentz invariance.
Dr
Azadeh Maleknejad
(Institute for Research in Fundamental Sciences)
25/09/2014, 16:10
We present a leptogenesis scenario associated with inflationary models involving non-Abelian gauge fields within the standard model of particle physics (SM). We show that this class of inflationary
models generates intrinsic birefringent gravitational waves that through the gravitational chiral anomaly in SM, can naturally create a net lepton number density. The CP violating interaction is...
Michele Re Fiorentin
(University of Southampton)
25/09/2014, 16:40
I will concentrate on the link between leptogenesis and low-energy neutrino data, showing how the baryon asymmetry of the Universe can constrain a type- I seesaw model and yield interesting predictions on the neutrino parameters. To this aim, I will consider the conditions required by strong thermal leptogenesis, where the final asymmetry is fully independent of the initial conditions. In this...
Dr
Narendra Sahu
(Indian Institute of Technology Hyderabad, India)
25/09/2014, 16:55
In the minimal supersymmetric standard model (MSSM) the lightest superpartner of the left-handed neutrinos is ruled out of being a candidate of dark matter because of its large elastic cross-section with the nucleus mediated via Z-boson. We resurrect it by extending the MSSM with two triplets with opposite hypercharge. The addition
of the triplets not only play a role in generating small...
Mr
Florian Führer
(ITP University Heidelberg)
25/09/2014, 17:10
I will present a new firsrt principle approach for higher order perturbation theory for massive neutrinos in large scale structure. The approach is based on a non-linear generalization of Gilbert's equation.
Combined with standard perturbation theory, it allows to calculate N-point statistics of density perturbations in mixed cold+hot dark matter cosmologies.
I apply the theory to compute...
