Gamma-Ray Bursts constitute one of the most fascinating and relevant phenomena in modern science, with strong implications for several fields of astrophysics, cosmology and fundamental physics. Indeed, the huge luminosity, the redshift distribution extending at least up to z~10 and the association with the explosive death of very massive stars make long GRBs (i.e., those lasting up to a few...
We develop a new method for estimating the decay probability of the
false vacuum via regularized instantons. Namely, we consider the case where the potential is either unbounded from below or the second minimum corresponding to the true vacuum has a depth exceeding the height of the potential barrier. In this case, the materialized bubbles dominating the vacuum decay naturally have a thick...
A vast body of astrophysical and cosmological observations point to the existence of an abundant form of matter interacting almost exclusively through gravity. A leading dark matter candidate is a weakly interacting massive particle, or WIMP, a thermal relic of the Big Bang, which has a sub-electroweak-scale self-annihilation cross-section and a mass in the TeV/c^2-range. The motion of...
Potassium-40 ($^{40}$K) is a naturally-occurring, radioactive isotope impacting understanding of nuclear structure, geological ages spanning timescales as old as the Earth, and rare-event searches including those for dark matter and neutrinoless double beta decay. In many advancing fields, the accelerating precision required for new discoveries has been limited by knowledge of the $^{40}$K...
The search for neutrinoless double beta (0$\nu\beta\beta$) decay is considered as the most promising way to prove the Majorana nature of neutrinos as well as to give indication on the mass hierarchy and on the absolute mass scale. The discovery of 0$\nu\beta\beta$ decay would moreover open the way for theories predicting the observed matter anti-matter asymmetry of the Universe being a...
The combination of experimental data from Observatories studying ultra-high energy cosmic rays, photons, neutrinos and gravitational waves, has provided in the last decade many insights on the most extreme phenomena in the Universe. This multi-messenger approach is shedding light on the physics beyond production and propagation of these messengers by exploring their intimate connection.
The...
AEgIS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) is an experiment at the Antiproton Decelerator (AD) facility at CERN that aims at investigating the asymmetry between matter and antimatter and, especially, the antihydrogen behaviour under Earth’s gravitational pull. In 2018, the first antihydrogen atoms were formed by charge exchange between Rydberg positronium and trapped...
XENONnT is a dark matter direct detection experiment employing a dual-phase time projection chamber, with 5.9 tonnes of liquid xenon and extremely low radioactivity. It's a multi-purpose particle astrophysics detector, mainly searching for dark matter, axion, and neutrinos. Since 2021, XENONnT has been taking science data and has reached the unprecedentedly low background in the keV region of...
I will describe the measurement of the CNO component of the Solar Neutrino spectra by the BOREXINO experiment at the Laboratori Nazionali del Gran Sasso in Italy. This, analysis, together with previous measurements of Solar Neutrino spectra, conclusively demonstrates the mechanism of energy generation in the Sun (and in Main Sequence Stars). The implication of the measurement on the details of...
The Pierre Auger Observatory, located in the Southern hemisphere in the province of Mendoza, Argentina, is the world’s largest cosmic ray experiment. It implements complementary detection techniques to observe cosmic ray induced air showers at energies far beyond the limits reached at the most powerful particle accelerators. During Phase I, for almost two decades, the hybrid design of the...
The study of ultra-high-energy cosmic rays (UHECR), i.e. nuclei exceeding energies of $10^{18}$ eV, and the extensive air showers they induce is closely intertwined with particle physics studied in experiments at accelerators, especially hadronic interactions. On the one hand, precise models of hadronic interactions, well constrained by accelerator data, are an invaluable ingredient to predict...
The Pierre Auger Observatory is currently the world’s largest detector for cosmic rays at the highest energies investigating their properties with unprecedented precision. The AugerPrime upgrade aims to enable mass sensitivity on an event-by-event level. Part of this upgrade is a Radio Detector (RD) that will increase the sky coverage of mass-sensitive measurements by measurements of inclined...
Recent direct measurements of the energy spectra of charged cosmic ray have revealed unexpected spectral features, most notably the onset of a progressive hardening at few hundreds of GeV/n not only of proton and He spectra but also observable for heavier nuclei. Thus, the study of the spectra behavior of heavy elements may shed light on understanding propagation and acceleration phenomena in...
Despite great efforts to directly detect dark matter (DM), experiments so far have found no evidence. The sensitivity of direct detection of DM approaches the so-called neutrino floor below which it is hard to disentangle the DM candidate from the background neutrino. One of the promising methods of overcoming this barrier is to utilize the directional signature that both neutrino- and...
It will be discussed how a component of the dynamical affine connection, which is independent of the metric, can drive inflation in agreement with observations. This provides a geometrical origin for the inflaton. It will also be illustrated how the decays of this field, which has spin 0 and odd parity, into Higgs bosons can reheat the universe up to a sufficiently high temperature.
(Based...
The LIGO-Virgo-Kagra (LVK) collaboration uses a subset of 47 gravitational-wave (GW) events from the third observing run to constrain the cosmology and in particular the Hubble constant $H_0$. The Hubble constant can be constrained using the luminosity distance inferred from each GW signals of compact binary coalescence, combined with an estimation of their corresponding redshift. Two...
Equations describing gravitational wave propagation over arbitrary curved space-time are derived. Some new terms absent in the FLRW background are obtained and their possible observational consequences are discussed.
The process of graviton-photon transformation in external magnetic field in the early universe are considered.
The sensitivity of gravitational wave (GW) interferometers is ultimately limited by
the quantum noise, which is due to vacuum fluctuations of the optical fields that entering from the dark port of the detector. Quantum noise affects the interferometer sensitivity in the entire bandwidth and it has two complementary effects: the shot noise, which depends on phase fluctuations of the optical...
We show how the mass and self-coupling of the QCD axion change at finite temperature and baryon density within the framework of Nambu-Jona-Lasinio model. We mainly focus on the effect of the chiral symmetry restoration and two flavor color-superconductivity on the axion properties by taking into account the charge neutrality constraint. We find that both the axion mass and self-coupling...
We consider the production of axion dark matter through the misalignment mechanism in the context of a nonstandard cosmological history involving early matter domination by a scalar field with a time-dependent decay rate. In cases where the temperature of the Universe experiences a temporary period of increase, Hubble friction can be restored in the evolution of the axion field, resulting in...
The study of cosmic rays with energies above $10^{18}$ eV contributes to a better understanding of the Universe. In particular, the study of anisotropy in their arrival directions is an important tool to unravel the sources of such particles. The state of the art in terms of experiments is currently represented by the Pierre Auger Observatory, the largest cosmic ray observatory in the world....
Detecting cosmic rays at ultra-high energies exploits the calorimetric properties of the Earth's atmosphere, yielding extended particle showers with billions of secondary particles. Besides the direction and energy of the showers, determining the cosmic ray mass is an important objective for understanding the origin of these cosmic messengers and their acceleration mechanisms. Two...
The SABRE (Sodium iodide with Active Background REjection) experiment aims to detect an annual modulation signature in the rate of events observed due to dark matter interactions in ultra-high purity NaI(Tl) crystals in order to provide a model independent test of the signal observed by DAMA/LIBRA. It is made up of two separate detectors; SABRE South located at the Stawell Underground Physics...
Muons in extensive air showers have large decay lengths and small
radiative energy losses. Therefore, muons can reach surface and underground detector arrays while keeping relevant information about the hadronic cascade. Data from several air shower experiments reveal inconsistencies in our current high-energy hadronic interaction models.
In most experiments, a larger muon content is...
Despite plenty of evidence for Dark Matter (DM) making up over 80% of the total matter in the universe, the quest of revealing its nature is still ongoing. The CRESST-III (Cryogenic Rare Event Search with Superconducting Thermometers) experiment is dedicated to direct DM detection. The sought-for signal is expected to originate from a DM particle scattering elastically off detector material...
Linearized gravity in the Very Special Relativity (VSR) framework is considered. We prove that this theory allows for a non-zero graviton mass $m_g$ without breaking gauge invariance nor modifying the relativistic dispersion relation. We find the analytic solution for the new equations of motion in our gauge choice, verifying as expected the existence of only two physical degrees of freedom....
Astronomical observations of the recent decade indicating to noticeable antimatter population in the Galaxy are reviewed. Different signatures of antimatter are discussed. Theoretical models leading to antistars in the Milky way are presented.
We present new soliton solutions in a class of four-dimensional supergravity theories. For special values of the parameters, the solutions can be embedded in the gauged maximal N=8 theory and uplifted in the higher-dimensional D=11 theory. We also find BPS soliton configurations, preserving a certain fraction of supersymmetry.
Solitons play a special role in classical physics as well as in...
About 70\% of the Universe is Dark Energy, but the physics community still does not know what it is. Delta Gravity (DG) is an alternative theory of gravitation that could solve this cosmological problem. Previously, we studied the Universe's accelerated expansion, where DG were able to explain the SNe data successfully. In this work, we explore the cosmological fluctuations that give rise to...
Darkside-20k is a global direct dark matter search experiment situated at Laboratori Nazionali del Gran Sasso, designed to reach a total exposure of 200 tonne-years free from instrumental backgrounds. The core of the detector is a dual phase time projection chamber (TPC) filled with 50 tonnes of low-radioactivity liquid argon. This is surrounded by an active neutron veto, employing...
LAG (Liquid Actuated Gravity) is an R&D experiment, funded by the Italian National Institute of Nuclear Physics (INFN), for the development and testing of a new actuation technique for gravity experiments, based on a liquid field mass. The basic idea of the experiment is to modulate the gravitational force acting on a test mass by controlling the level of a liquid in a suitable container,...
Recently, the anomalous transport phenomena of relativistic fermions associated with chirality induced by external fields have been greatly explored in different areas of physics. Notably, such phenomena are in connection with various quantum effects such as the chiral anomaly and spin-orbit interaction. These chiral effects like the chiral magnetic and vortical effects have been recently...
The Pierre Auger Observatory is the world's largest detector of
ultra-high-energy cosmic rays (UHECRs). Since the start of its operation
in 2004, a data set unrivaled both in quality and statistics was collected
with the Observatory using the fluorescence and surface detectors.
Currently, an upgrade of the Observatory, AugerPrime, consisting of the
addition of surface scintillator,...
DarkSide-20k is the nearest goal of the Global Argon Dark Matter
Collaboration program and will be operated in Hall C of Gran Sasso
National Laboratory. It consists of a multi-ton ultra-low
background dark matter detector, based on a dual phase Time Projection
Chamber filled with low radioactivity argon instrumented with cryogenic
photosensors. Among of the the key features of the...
Einstein Telescope (ET) will be the European third-generation of gravitational wave interferometer. In Sardinia, the region around the former mine of Sos Enattos (Lula, Nuoro), is one of the sites candidates to host this new experiment. The site satisfies the scientific requirements mainly concerning geology, environmental and seismic noise. In this talk, an overview of the ongoing activities...
Astroneu is an array of autonomous Extensive Air Shower detection stations deployed at the Hellenic Open University (HOU) campus on the outskirts of Patras in western Greece. In the first phase of operation 9 scintillators detectors and 3 Radio Frequency (RF) antennas have been installed and operated at the site. The detector units were arranged in three autonomous stations each consisting of...
Our aims to study the quark-gluon plasma (QGP), theorised to
have been present during the early and expanding stages of our universe. Through the equations of state (EoS) of temperature, pressure and energy density, we can understand more about the evolution of the early universe QGP. The Friedmann equations (derived from the Einstein field equations) are solved by utilising a...
A Schwarzschild black hole is simulated by a set of Unruh particle sources. The approach allows to calculate the ratio of Unruh radiation to the Bekenstein-Hawking entropy analytically. The contribution of mass and spin of the emitted particles to total entropy is taken into account.
General Relativity (GR) and Quantum Mechanics (QM) are fundamentally different theories explaining how nature works but with genuinely incompatible descriptions of reality. While GR handles gravitational force, at large scale, QM is the theory for the other fundamental forces of nature, at low scale. Events in GR happen continuously with deterministic outcomes. In QM, they happen in jumps with...
Small review of no-go theorem in scalar-tensor theory (Horndeski theory and beyond) and recent advances in possibilities to avoid it. That includes disformal connection between different subclasses, models with strong gravity in the past and some special cases without instabilities.
We study the possibility to construct a stable wormhole-like solution within scalar-tensor theories of modified gravity of beyond Horndeski type. We pay special attention to the behaviour of perturbations around the wormhole solution in the linearised theory and ensure that there are no pathological degrees of freedom which are able to ruin the solution. In result we suggest a specific example...
