Séminaire

Gravitational waves from the early-universe turbulent sources

A space-based laser interferometer, pioneered by NASA's LISA concept and now a ESA cornerstone mission, will enable direct detection of gravitational waves at lower frequencies than LIGO, without being limited by seismic noise. Perhaps the most intriguing source for LISA is the stochastic gravitational wave background produced by turbulent plasma motions in an early-universe, particularly at the electroweak energy scale.

Two recent topics in gravitational-wave cosmology: Binary resonance searches and nonlinear memory from cosmic strings

In the first half of this talk, I will discuss how binary systems can be used as dynamical detectors of gravitational waves (GWs). Since the passage of GWs through a binary perturbs the trajectories of the two bodies, we can infer the presence of a GW signal by searching for changes in the binary's orbital parameters. In the presence of a stochastic GW background (SGWB) these changes accumulate over time, causing the binary orbit to execute a random walk through parameter space.

Multimessenger astroparticle physics

I will present a bit more extended version of the talk that I gave recently at the TAUP2021 conference, with overview of the recent developments in the multi-messenger astronomy.

The astrophysics of black hole binaries in the era of gravitational wave astronomy

Black holes (BHs) cover a wide range of mass: from the stellar BH binaries detected with LIGO / Virgo to the massive BHs residing at the center of galaxies. Both these populations will be detectable in future by LISA at low-frequency. In this talk, I will provide a general overview of the current detections from LIGO / Virgo, describing the current state-of-the-art and I will highlight the potential of the LISA mission.

Gravitational wave probes of primordial black holes

The dawn of gravitational wave (GW) astronomy has enabled new probes of dark matter. In particular, the formation and abundance of primordial black holes (PBHs) can be probed through GWs. In this talk I will discuss different ways how GW observations can be used to probe PBHs and I will review the implications of LIGO-Virgo observations on PBHs.

From the representation of de Sitter group to the quantum field theory

A rigorous mathematical consideration of quantum field theory in de Sitter universe is briefly presented in ambient space formalism. This formalism permit us to solve some physical and mathematical problems in de Sitter space-time.

ECFA workshops on e+e- Higgs/EW/Top factory

Dear Colleagues,

with this email we would like to remind you on the upcoming kick-off meeting on 18th June for ECFA workshops on an e+e- Higgs / top / electroweak factory. More information is given in the email below.

Meanwhile the speakers at the kick-off meeting have been defined by the Working Group conveners. The agenda is available here: https://indico.cern.ch/event/1033941/

First signs of the Glashow resonance from an astrophysical (anti)neutrino

The Glashow resonance describes the resonant formation of an on-mass W- boson via the scattering of an electron antineutrino and an electron, a process first predicted in 1959. In the electron rest frame, the requisite neutrino energy of 6.3 PeV lies beyond the reach of terrestrial accelerators. However, the discovery of a diffuse flux of astrophysical neutrinos by IceCube gave rise to the possibility of detecting the resonance via high-energy (anti)neutrinos from outer space.

Gravitational Waves in a model of Inflationary Magnetogenesis

Gravitational waves (GW) can be used to probe various epochs in the early Universe. In this talk I will discuss about the production of Gravitational waves in a particular model of inflationary magnetogenesis. In this model, we require a low energy scale for inflation and reheating (reheating temperature, TR < 104 GeV) and have a blue spectrum of electromagnetic (EM) field which peaks around the horizon scale of reheating.

Searches for High-Energy Neutrinos from the Sun

Abstract: While the Sun has already proved a fruitful laboratory for neutrino physics, high-energy solar neutrinos may continue to provide insight. For example, current-generation neutrino telescopes have searched for an excess of neutrinos from the Sun’s direction as evidence of annihilating weakly interacting massive particles (WIMPs) at energies from ~0.1 GeV to 10^4 GeV. Detection of these neutrinos would be a smoking-gun signature of WIMPs since backgrounds from the Sun are well-understood.

Séminaire