The non-linear, late-time evolution of cosmic structures is notoriously hard to tackle with analytic methods. While numerical simulations are highly successful and lead to impressive results, there are fundamental as well as pragmatic reasons for an analytic understanding to be sought. Conventional methods based on the hydrodynamic equations are limited mainly by the shell-crossing problem. In...
Empirical motivations for new physics, e.g. the need to explain dark matter and neutrino mass, arguably point to a hidden/dark sector, weakly coupled to the Standard Model. I’ll discuss the impact of low energy precision and high-intensity experiments in testing this theoretical paradigm.
The existence of dark matter DM is well established from cosmological observations. While large scale structure formation, rotation curves of galaxies and gravitational lensing all clearly indicate the presence of DM in the Universe, the microscopic particles responsible for these observation still hide from laboratory discovery. A viable class of hypothetical particles which could make up DM...
Atomic physicists have spent decades developing tools to gain complete quantum control of atoms and ions. These tools have used them to make ever increasing precision measurements - the most prominent example being atomic optical clocks which can now measure frequencies to $10^{-19}$ precision. Recently there has been increasing interest in leveraging these precision tools to look for small...
The Standard Model may be a valid effective field theory all the way up to the Planck scale, still it suffers from a number of theoretical and observational shortcomings. I will overview the theoretical, phenomenological and cosmological arguments for a possible existence of new particles with masses below the Fermi scale and discuss the experimental prospects to search for them.
Even though the Cosmic Microwave Background (CMB) is a photograph of the Universe when it was about 400000 years old and had a temperature of about 0.3eV, it contains information about a much earlier phase of the Universe, most notably inflation.
In my talk I shall describe the amplified quantum fluctuations which we observe in the CMB. I shall discuss what we already know and what we might...
I will describe several features of type IIB Fibre Inflation models like:
(i) how to construct a chiral global embedding into consistent Calabi-Yau orientifold compactifications;
(ii) the presence of an inflaton upper bound from the Kahler cone conditions;
(iii) the details of perturbative reheating and the associated production of dark radiation;
(iv) the generation of primordial black...
The ability to directly detect gravitational waves from merging binary
black holes gave us our first-ever access to the genuinely strong-field
dynamics of gravity. In 2017 a binary neutron star coalescence was also
observed, accompanied by a short gamma ray burst, thus corroborating the
link between the two. The discovery of an afterglow gave a glimpse of
the putative formation mechanism for a...
Recent gravitational wave (GW) detections with LIGO/Virgo opened a new window on
the Universe, unveiling the most violent catastrophic events in the cosmos. GW
astronomy is just in its infancy, the Laser Interferometer Space Antenna (LISA)
and Pulsar Timing Arrays (PTAs) will offer a complementary view of the GW
universe in a much more extended range of frequencies, from mHz down to nHz....
The gravitational waves from a neutron star binary inspiral carry unique information about fundamental physics in extreme conditions. I will discuss the imprints of the properties of neutron star matter on the gravitational waves, what we have learned from the neutron star binary inspiral event GW170817, and outline future prospects and challenges.
We are entering a transformative period in observational cosmology. Surveys starting in 2019 promise to solve key problems in cosmology — but only if we develop new approaches for handling the volume and complexity of the data. Extracting robust cosmological information from these surveys is a major challenge that will require development and validation of analysis methods at each step of the...
I will discuss different ways to constrain the nature of dark matter using gravitational probes from current and future astrophysical surveys. The focus will be on non-cold and interacting dark matter models.
I will review cosmological probes of dark matter physics, focusing in particular on the most recent results relating to dark-matter--baryon elastic scattering.
The Axion Dark Matter Experiment (ADMX) is currently taking data with sensitivity towards discovery of the axion that simultaneously solves the strong-CP problem of quantum chromodynamics (QCD) and accounts for the dark matter of the universe. Details will be given of the microwave cavity haloscope technique and recent published results demonstrating sensitivity in the axion coupling to two...
The presence of a cosmic background of relic neutrinos is a robust prediction of the standard cosmological model. A direct detection is extremely difficult and still lacking. Nevertheless cosmological observations are a powerful probe of neutrino properties, and cosmological bounds on neutrino masses and number are in agreement with both theoretical predictions and laboratory searches.
In this...
The NOvA experiment is a two detector long baseline neutrino oscillation search. This talk will show the latest results from NOvA with both a neutrino and antineutrino beam. Implications for the future will also be discussed with a particular emphasis on leptonic CP violation.
The experimental setup and results of the first search for invisible decays of ortho-positronium (o-Ps) confined in a vacuum cavity are reported. No evidence of invisible decays at a level $\text{Br}\left(\text{o-Ps}\to\text{invisible}\right) < 5.9\cdot10^{-4}$ (90 % C. L.) was found. This decay channel is predicted in Hidden Sector models such as the Mirror Matter (MM), which could be a...
Mu3e is an experiment for the search for the charged lepton flavour violating decay $\mu \rightarrow \mathrm{eee}$ with a single event sensitivity of $10^{-16}$, which is an improvement of 4 orders of magnitude over the current limit of $B < 10^{-12}$ (90% CL, SINDRUM, 1988).
This poster explains the general detector concept and lays focus on the scintillating fibre sub-detector. High muon...
Antihydrogen is a blossoming field of research which studies aim to shed light on the observed baryon/antibaryon asymmetry in the Universe. The GBAR project (Gravitational Behaviour of Antihydrogen at Rest) at CERN aims to measure the free fall acceleration of ultracold neutral antihydrogen atoms in the terrestrial gravitational field. The experiment consists of preparing antihydrogen ions in...
In this poster, I review how the CMB (in particular its temperature and polarization anisotropies) can be used to look for ultra light axion-like particles (ULAs).
Such ULAs are numerous in the axiverse scenario and can play many role in cosmology, from Dark Matter to Dark Energy. Moreover, they have been invoked to solve several recent cosmological tensions. In particular, ULAs can...
Cosmological relaxation of the electroweak scale is improved by using particle production to trap
the relaxion. We combine leptogenesis with such a relaxion model that has no extremely small
parameters or large e-foldings. Scanning happens after inflation now allowed to be at a high
scale over a sub-Planckian relaxion ?field range for an O(100) TeV cut-off? scale of new physics.
Particle...
We build two families of inspiral waveforms for precessing
binaries on eccentric orbits in the Fourier domain. To
achieve this, we use a small eccentricity expansion of the
waveform amplitudes in order to separate the periastron
precession timescale from the orbital timescale, and use a
SUA transformation to compute the Fourier transform
in the presence of spin-induced precession. We show...
We investigate the sensitivity to additional gravitational wave polarization modes of future detectors. We study the correlation of the upcoming Einstein Telescope and its combination with existing or planned Earth-based detectors with a possible future space-borne detector like DECIGO. The cases of a gravitational wave background and point sources are considered.
In this talk, a brief description of the latest results in exotic searches using data collected in 2016 by the CMS and ATLAS experiments at the LHC. This talk focuses on searches using Lorentz-boosted hadronic objects which are enhanced by the current conditions of the LHC.
Despite the absence of experimental evidence, weak scale supersymmetry remains one of the best motivated and studied Standard Model extensions. This talk gives an overview of the most recent SUSY searches at ATLAS and CMS experiments using 13 TeV Run2 data.
ATLAS and CMS have rich programs to explore the BSM territories in Higgs physics. The latest LHC results on Higgs rare, exotic and invisible decays are briefly reviewed in this talk.
The search programmes for long-lived and dark sector particles have been gaining momentum at ATLAS and CMS as LHC Run 2 nears its end. These unconventional signatures are well motivated but were often not among the first targets of Run 2 due to requiring complex experimental techniques such as dedicated triggers, reconstruction, or calibration. New results will be highlighted from both...
The Lepton Flavour Universality (LFU) anomalies are currently one of the hottest topics in the particle physics community. LFU can be violated in models beyond the SM by new physics particles that couple preferentially to certain generations of leptons. A combination of recent results from LHCb, Belle and BaBar on the ratio of branching fractions of tree level b->clν processes have shown a...
New methods of big data analysis, data mining, data generations and data adaptation are widely used in many different areas of the modern society. This is mostly a result of fruitful cooperation between corresponding business experts and experts in relevant areas of the computing science. Natural sciences however, especially those frontiers like particle physics and cosmology at their extremes...
In this talk, I’ll focus on an exceptional way of doing data-driven research employing networked community. Many examples of collaboration with the data-science community within competitions organised on Kaggle or Coda Lab platforms usually get limited by restrictions on those platforms. Common metrics do not necessarily correspond to the goal of the original research. Constraints imposed by...
The origin and observed abundance of Dark Matter can be explained elegantly by the thermal freeze-out mechanism, leading to a preferred mass range for Dark Matter particles in the MeV-TeV region. The GeV-TeV mass range is being explored intensively by a variety of experiments searching for Weakly Interacting Massive Particles. The sub-GeV region, however, in which the masses of most of the...
The NA62 fixed target experiment, which operates on a very high intensity, 400 GeV/c primary proton beam supplied from the CERN SPS accelerator facility has a great potential to search for new particles at MeV-GeV scale. Very weak coupling with the SM sector is assumed. New Physics models such are heavy neutral leptons, axion-like particles, dark photons and scalars are being studied at NA62....
This talk will give an overview of searches for WIMP Dark Matter exploiting signatures of large missing transverse energy (MET) at both ATLAS and CMS. The so-called MET+X searches are performed for various objects X and cover a broad range of DM scenarios. The talk will focus on recent results using 13 TeV data sets, new techniques that are employed and new models that are tested.
This talk presents results from the ATLAS and CMS experiments on searches for dark matter mediator particles. First, searches targeting new vector bosons decaying into dijet final states are described. Techniques for studying low-mass resonances below the typical threshold for conventional dijet resonance searches are emphasized, including the use of data scouting, online bottom quark tagging,...
I will talk on 1 of the following:
1) Generating neutrino mass via fermion kinetic mixing. I this work we show how neutrino masses can be obtained from the radiative fermion mixing of 2 or more dark fermions and what kind of consequences and signatures this scenario can have compared to other similar models of neutrino mass.
2) I this work we demonstrate how Scotogenic neutrino mass...
Cosmology presents the best hope of measuring the sum of neutrino masses in the future. The CMB has already been a treasure trove of information and will continue to provide ever more precise information with upcoming or proposed CMB experiments, such as LiteBird, CMB-S4, CORE, and PICO. These missions will have great synergy with other branches of cosmology. In particular, massive neutrinos...
NA64 is a fixed target experiment at the CERN SPS to search for hidden sectors. In this poster, we will present our latest results on the search for a new sub-GeV vector gauge boson (A′) mediated dark matter (χ) production. The A′, called dark photon, could be generated in the reaction e−Z→e−ZA′ of 100 GeV electrons dumped against an active target which is followed by the prompt invisible...
The standard Dark Matter paradigm, in which Dark Matter is cold, collisionless, and only interacts significantly gravitationally, boasts remarkable success on large scales. However, possible tensions in H0 and S8 measurements have reinvigorated interest in beyond-LCDM models, such as interactions between all or a fraction of Dark Matter and Dark Radiation. Here I present recent constraints on...
This article presents cosmological models that arise in a subclass of $f(R,T)=f(R)+f(T)$ gravity models, with different $f(R)$ functions and fixed $T$-dependence. That is, the gravitational lagrangian is considered as $f(R,T)=f(R)+\lambda T$, with constant $\lambda$. Here $R$ and $T$ represent the Ricci scalar and trace of the stress-energy tensor, respectively. The modified gravitational...
Cosmological inflation generates primordial density perturbations which are scale-free on observable scales but that may be considerably larger on smaller scales. The boosted power spectrum at small scales leads to increased formation of dense, small-scale structure at early times, enhancing the present-day annihilation rate of annihilating dark matter. In this work, we show how to compute the...
We perform a large scale (3+1)-dimensional numerical simulation of the axion field around the QCD epoch. Our aim is to fully resolve dynamical non-linear effects in the inhomogeneous axion field, collapsing domain walls and oscillons. These effects are important as they lead to large overdensities in the energy density at late times. Those overdensities will eventually collapse into axion...
