A new method is presented for calibrating hadronic tau leptons ($\tau_h$) using $Z \rightarrow \mu \tau_h$ events, recorded by CMS experiment during 2018 at $\sqrt{s}$ = 13 TeV. The calibration is performed using data samples that reconstruct the decay of a Z boson into $\tau_{\mu}\tau_h$. By reconstructing the invariant visible mass from the visible decay products, a distribution is obtained...
The first part of the presentation is focused on a current LHCb analysis about the measurement of the branching fraction of the $B^0_{d(s)}\to K^0_Shh’$ modes, where $h$ and $h’$ could denotes a pion or a kaon, by using the LHCb Run1 and Run2 data. The first goal of the analysis is to measure the $B^0_d\to K^0_S K^+K^-$ decay mode unobserved to date. The second goal of the study is to update...
The observable Universe is mainly made up of matter, while almost all the antimatter disappeared in the very early times. One explanation is that the Universe obeys the Sakharov conditions, which mean the existence of a C (charge) and CP (charge - parity) symmetry violation. An area of Particle Physics deals with the comprehension and measurement of this symmetry breaking and the potential...
Jets are collimated sprays of particles that stem from the emission of a quark or a gluon. They are crucial for many Standard Model measurements and search for new physics and they are ubiquitous in high energy proton-proton collisions environments, such as at LHC. The goal of jet calibration is to get the true 4-momentum of the jet, which is that of the particle initiating it, from the...
In the current ATLAS jet calibration procedure, the GSC/GNNC methods are applied to improve the Jet Energy Resolution (JER) followed by various methods measuring the JER in situ and correcting it.
This project focuses on merging several aspects of the jet calibration chain, combining a NN-based calibration procedure with a loss function that minimises the JER directly in data. As a first...
Several intriguing hints on deviations from the SM predictions have appeared in the studies of decays of B hadrons (hadrons containing the beauty (b) quark) involving leptons. The standard model contains three lepton families: electrons, muons, and tau-leptons, each accompanied by the corresponding type of neutrino. The most striking deviation is the hint on violation of lepton flavor...
Over the next decade, increases in instantaneous luminosity and detector granularity will increase the amount of data that has to be analyzed by high-energy physics experiments, whether in real time or offline, by an order of magnitude. The reconstruction of charged
particles, which has always been a crucial element of offline data processing pipelines, must increasingly be deployed from the...
In anticipation of the High-Luminosity phase of the Large Hadron Collider at CERN (HL-LHC), the ATLAS experiment is upgrading its innermost detector to the new Inner Tracker (ITk), characterized by its wider coverage and increased granularity. While this new detector promises enhanced spatial resolution for track measurements, its combination with the increased luminosity of the HL-LHC poses a...
In 2029, the High Luminosity phase of the LHC (HL-LHC) is planned to begin taking data, bringing an unprecedented level of radiation and average particle interactions per brunch-crossing (pileup/PU). In order to preserve the same physics performance that the CMS detector achieves now, the collaboration has decided to replace the endcaps of the current electromagnetic and hadronic calorimeters...
Nuclear activation is the process of production of radionuclides by irradiation. This phenomenon concerns all operating or soon-to-be dismantled particle accelerators used in various fields, from medical applications with the production of radioisotopes or radiotherapy cancer treatments to industrial applications with the sterilization of materials and food preservation [1]. For more than...
I will present the construction of a Hubble diagram, especially the standardisation of Type Ia Supernovae luminosity. I will then talk about the ongoing ZTF survey, which is the current state of the art low redshift survey. I will then talk about one of the challenge faced by Supernovae cosmology now: the astrophysics dependency of Type Ia Supernovae.
The 21cm hydrogen line is present during all the eras following the cosmological recombination, containing information about both the cosmology and the astrophysical processes at work in the universe.
During this presentation, I will discuss the 21cm emission from collapsing gas clouds. I will particularly take into account the gas cooling due to thermal molecular functions. To do so, one...
A search for the resonant production of a heavy scalar X decaying into a Higgs boson and
a new lighter scalar S, through the process X$\rightarrow$ S ($b\bar{b}$) H($\gamma \gamma$), where the two photons are consistent with the Higgs boson decay, is performed. The search is conducted using 140 fb$^{-1}$ of LHC Run 2 data recorded by ATLAS. The mass space investigated in the analysis is 170...
Deviations from the Standard Model have long been observed in semileptonic B-meson decays, notably b→ sll transitions, triggering speculations on potential New Physics effects in this sector. After the recent update of RK(*) and BR(B(s) → μμ) by the LHCb collaboration, the remaining significant deviations from the SM in FCNC B decays are found in the branching ratios of mesonic decays...
The pursuit of deviations from the Standard Model (SM) is prompted by the recognition of the model's known limitations. Some findings suggest possible violations of lepton universality. The identification of such deviations could potentially lead to a SM extension, adding Z' boson that interacts with leptons in a different manner.
The SM is also firmly grounded by the principle of Lorentz...
Vector boson scattering (VBS) processes probe the fundamental structure of electroweak interactions and provide a high sensitivity to new physics (NP) phenomena affecting gauge and Higgs couplings. These processes are among the rarest ones in the Standard Model (SM) and were observed during last years in the Large Hadron Collider (LHC). The semileptonic final state, where one of the scattered...
Since the existence of the Higgs boson has been experimentally confirmed by the ATLAS and CMS Collaborations, many of its properties have been measured with high precision. However, one of its main property, the shape of the Higgs potential, remains unknown. The Higgs pair production represents the most direct way of measuring this potential, and any excess observed could be a sign of new...
Une recherche de particules de matière noire produites en association avec un nouveau boson vecteur neutre est effectuée en utilisant des collisions de protons-protons à √s=13 TeV, correspondant à une luminosité intégrée de 140 fb−1 enregistrée par le détecteur ATLAS au Grand Collisionneur de Hadrons. Les désintégrations du boson Z′ en leptons légers de même saveur (e+e−/μ+μ−) sont étudiées...
My thesis subject aims to search for long-lived decays
of new massive particles in the Compact Muon Solenoid
(CMS) experiment at the Large Hadron Collider (LHC).
CMS is one of the four main experiments at the LHC,
where high energy proton-proton collisions are pro-
duced. New long-lived particles are predicted in several
extensions of the Standard Model (SM). In the model
considered,...
The Standard Model (SM) cannot explain the composition of Dark Matter in the Universe. Some Beyond Standard Model theories predict the existence of a dark hidden sector which contain new hypothetical particles : stable particles in this sector are Dark Matter candidates. The new particles could weakly interact with Standard Model ones through a new interaction, and thus can be produced in...
The expected increase of the particle flux at the high luminosity phase of the LHC (HL-LHC) with instantaneous luminosities up to L ≃ 7.5×1034 cm−2 s-1 will have a severe impact on the ATLAS detector performance. The pile-up is expected to increase on average to 200 interactions per bunch crossing. The reconstruction and trigger performance for electrons, photons as well as jets and transverse...
Ion beam analysis has been developed at ARRONAX cyclotron in Nantes [1]. Light ions including $H^{+}$ and $He^{2+}$ are accelerated to reach the required energy for the analyses before being extracted in-air. We use a fixe 68MeV α beam and several proton beams at 17MeV to 70MeV. We will explore the specific interest concerning material analysis by beam irradiation. Interaction between ions...
La réduction de la dose délivrée par les scanners est un enjeu majeur de santé publique [1]. L’objectif est d’obtenir des images scanner qui permettent une interprétation médicale avec une dose la plus faible possible.
La plateforme de simulations Monte Carlo GATE (version 10 béta) est utilisée dans le cadre de la modélisation du scanner Go Open Pro de Siemens Healthineers.
La version 10...
Dark matter is one of the major puzzles in fundamental physics. Axions are among the best-motivated dark matter candidates. MADMAX experiment will search for axions in the mass range around 100 $\mu$eV, which is favored by theory. Traditional axion cavity experiments are unable to access this mass range. Therefore, a novel detector called dielectric haloscope will be utilised for this...
Active Galactic Nuclei (AGN) stand as enigmatic cosmic powerhouses, harboring supermassive black holes at their centers. Blazars are AGN with a jet oriented toward the observer. Their emission spans from radio to very high-energy gamma rays. Understanding their spectral variability provides crucial insights into the underlying physics governing these astrophysical phenomena. The Cherenkov...
The flares of active galactic nuclei (AGNs) can be used to detect or constrain Lorentz invariance violation (LIV) by measuring time lags in detection of high energetic photons. An important source of uncertainty is our lack of knowledge of source intrinsic processes. However, combining flares and sources allows us to increase the precision of these measurements as well as to limit the noise of...
Virgo is a gravitational wave detector located near Pisa in Italy. It is composed of a Fabry-Perot Michelson Interferometer and allows to detect gravitational wave passing through it using the interference dark fringe signal going out of the interferometer.
Virgo is an instrument that needs to be controlled and calibrated with great accuracy in order to achieve the precision required to...
The interstellar medium is made up of gas and dust. This medium is traversed by cosmic radiation and irradiated by stellar UV, except in dense clouds where UV is absent. The interaction of these rays with the dust and gas is crucial to the chemical evolution of interstellar and circumstellar environments. Heavy and slow cosmic rays interact with very small dust particles (-100 atoms) and...
The mysterious nature of Dark Matter (DM) has puzzled physicists the world over. One well-motivated class of DM candidates is Weakly Interacting Massive Particles (WIMPs). The XENON Dark Matter Project for direct search for WIMPs currently operates XENONnT experiment, lying a dual-phase (liquid & gas) xenon time projection chamber (TPC), situated in the underground LNGS in Italy.
This...
The quest for PeVatrons, sources of cosmic rays accelerated up to PeV energies, saw an exciting development in 2021 when LHAASO detected 12 ultra-high energy (UHE) gamma-ray Galactic sources. Among those sources, the supernova remnant G106.3+2.7 (also called the Boomerang SNR) is a promising candidate to both hadronic and leptonic scenarios for the UHE emissions.
Gamma-ray astronomy...
Heavy quarkonia are considered among the most promising probes of quark
gluon plasma (QGP) formed in ultra relativistic heavy ion collisions (URHIC).
For a reliable use of such probe, we need a rigorous formalism which could
describe the real time and out of equilibrium evolution of in-medium quarkonia
while it keeps a full track of the quantum nature of our system, as well, being
derived...
KM3NeT/ORCA is a large-volume water-Cherenkov neutrino detector, under construction at the bottom of the Mediterranean Sea at a depth of 2450 meters. The main research goal of ORCA is the measurement of the neutrino mass ordering and the atmospheric neutrino oscillation parameters. Additionally, the detector is also sensitive to a wide variety of phenomena including non-standard neutrino...
The KM3NeT experiment is a next-generation neutrino telescope, consisting of two separate detection structures, organised as arrays of light sensors, and immersed in the depths of the Mediterranean Sea. The two detectors are the Oscillation Research with Cosmics in the Abyss (ORCA detector), located off the coast of France and the Astrophysics Research with Cosmics in the Abyss (ARCA...
Deep Underground Neutrino Experiment (DUNE) is a next generation long-baseline neutrino experiment in the United States.
Its main goal is to make precise measurements of neutrino oscillation parameters and to discover the neutrino mass ordering and CP violation phase in the leptonic sector.
The experiment is made of two elements: the near detector close to neutrino beam source and the far...
The Deep Underground Neutrino Experiment (DUNE) is a long baseline neutrino experiment under construction that aims to address the main open questions in neutrino physics such as the ordering of the mass hierarchy and the precise measurement of the neutrino oscillation parameters, including the charge-parity violation phase to determine the existence (or not) of the CP-violation in the...
The XENON program aims to directly detect dark matter. As dark matter interacts very weakly, the sensitivity of dark matter experiments has greatly increased over the last two decades. XENONnT, the current XENON detector should be able to study solar neutrinos. This detector is designed to be sensitive to low-energy nuclear recoils which is the expected signal from some dark matter candidates....
Ion acceleration from optically shaped high density gas jet targets
