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08-11-2023 (aula F)
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ore 15:00
| Pietro Meloni (DOTTORATO IN FISICA) | The CYGNO Experiment: A Directional Detector with Optical Readout for Dark Matter Search
The CYGNO project aims to prove the feasibility of utilizing a gaseous Time Projection Chamber (TPC) with optical readout to investigate Dark Matter (DM) in the low-mass range (1 GeV/c$^2$). A key feature of the CYGNO project is the ability to determine the direction of the recoiling nuclei, which is of great importance in DM search.
The proposed detector includes a TPC chamber filled with a mixture of He:CF$_4$ at ambient pressure and temperature. The directionality of nuclear recoils can be determined by analyzing the distribution of primary electrons generated by the ionizing nucleus. Primary electrons are amplified using a triple layer of Gas Electron Multipliers (GEMs), and the resulting photons are detected by an external sCMOS camera and four PMTs.
The purpose of this presentation is to share the latest findings from the latest prototype, LIME, with a volume of 50 liters, currently at Laboratori Nazionali del Gran Sasso (LNGS). The focus will be on the comparisons between experimental data and simulations, as well as the next steps for the LIME prototype |
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ore 15:30
| Laura Salutari (DOTTORATO IN FISICA) | Dark photon and dark Higgs at the Belle II experiment
Abstract:
Many questions remain open in the Standard Model of particle physics, and nowdays physicists seek for the answers with a wide range of experiments. Among all the collaborations, Belle II, a B-factory located in Japan, also has in its program to search for Beyond SM physics. In particular, it has an on going search for Dark Matter particles. The study project presented here is based on the simultaneous production of a dark photon A’ and dark higgs like boson h’, predicted in a variety of dark sector models, at the Belle II experiment. The research focus on the channel e^+ e^-→(A^'→μ^+ μ^- )h' with a center of mass energy s=(10.58GeV)^2. This channel offers at least three different studies, covering a great deal of the still available parameter space of the theoretical models. One project is the update of a previous study published in 2022, in which the h’ is considered an invisible long lived particle and a luminosity l=8.34fb^(-1). The update will consist in using the lates available luminosity of l=427fb^(-1), which could lead to a significative improvement of the previous results on the cross section sensitivity of the experiment. Another project is to expand the research including the so called visible h’ hypothesis: to consider also an h’ decaying into SM particles, so a channel such as e^+ e^-→(A^'→μ^+ μ^- ) (h^'→l^+ l^- ). This project in fact can be further subdivided in two studies. One is to consider an h’ sufficiently long lived so that its decay particles have a displaced vertex with respect the IP; one in which instead the lifetime is short and the h’ decays prompt, leaving no sign of displaced vertex.
In the talk I will present the proper background in order to understand the three new scenarios and explain the setup work done up to now for these three different projects.
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ore 16:00
| Elia Stanescu Farilla (DOTTORATO IN FISICA) | Study of the reactor electron antineutrino energy spectrum for the search of light sterile neutrino at the TAO experiment
Neutrino oscillations have been measured with high accuracy in solar, atmospheric and long-baseline neutrino oscillation experiments. Several anomalies recorded in short-baseline neutrino experiments suggest the possibility that the standard 3-flavour framework may be incomplete and point towards a manifestation of new physics. Light sterile neutrinos provide a credible solution to these puzzling results.
The Taishan Antineutrino Observatory (TAO) is a state-of-the-art ton-level liquid scintillator detector, satellite experiment of the Jiangmen Underground Neutrino Observatory (JUNO) experiment, that will start by the end of 2024. Thanks to the record energy resolution of 1% at 1 MeV that aims to reach, TAO will provide an extremely accurate measurement of the reactor electron antineutrino energy spectrum.
Simulations of the spectrum will be realized in the 3-flavour and 3+1 light sterile neutrino-flavour frameworks, with the aim to reproduce the anomalies showed by the previous short-baseline neutrino oscillation experiments.
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10-10-2023 (AULA C - piano terra - Via della Vasca Navale n. 84)
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ore 15:30
| Daniele Tagliacozzo (DOTTORATO IN FISICA) | The geometry of the hot corona in Radio Quiet AGN constrained by X-ray polarimetry
The X-Ray spectra of Radio Quiet Active Galactic Nuclei (RQ AGN) are dominated by radiation emitted via accretion onto a supermassive black hole and energized via comptonization in a hot and compact medium of unknown geometry and enigmatic physical origin: the corona. Now, the NASA-ASI mission IXPE is giving us the chance to unveil the X-Ray polarization properties of these objects, aligning a new tool to spectroscopical analyses.
In this talk I will present the IXPE view of RQ AGN. Indeed, IXPE observed three of these sources in its first two years of activity (NGC 4151, MCG-05-23-16 and IC4329A). I will discuss the spectropolarimetric analysis of MCG-05-23-16, which I dealt with personally, in detail and summarize the analyses of the other two sources, trying to point out the hints we got on the morphology of the comptonizing medium obtained through a comparison with simulations performed with the Monte Carlo code MONK.
Then, I will briefly summarize the future steps in order to shed finally light on the enigmatic origin of the AGN corona.
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ore 16:00
| Dario Vincenzi (DOTTORATO IN FISICA) | Automatic Generation of Redundant
Configuration in FPGAs
Field programmable gate arrays (FPGAs) play a key role in nuclear and particle physics experiments for real-time data transfer and processing. The usage of such devices in the radiation environments of detectors at colliders or at fixed-target experiments requires to cope with radiation effects. Radiation- induced single event upsets in the device configuration are the dominant issue for static random-access memory based (SRAM-based) FPGAs. Solutions based on configuration redundancy have been proposed for hardening the configuration memory of commercial off-the-shelf SRAM-based FPGAs. In these solutions, the configuration is majority voted by the firmware to correct configuration errors.
In this tal, I will introduce an automatic methodology to generate a redundant configuration for SRAM- based FPGAs. The methodology is based on copying the configuration fragments to be protected to unused ones, measuring the impact of the copy on the power consumption of the FPGA and on the functionality of the firmware. This method can be considered as an additional step in the design flow for FPGAs, and it runs after the bitstream generation. Different from others in the literature, this method is completely agnostic with respect to the device, the only requirement being the possibility to write and read back the configuration, which is supported by most of the modern FPGAs.
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21-09-2023 (AULA B -piano terra - V. della Vasca Navale n. 84)
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ore 16:30
| Bianchi Lucrezia (DOTTORATO IN FISICA) | The role of Monte Carlo simulations in the characterization of diamond integrated devices for hadrontherapy
Abstract:
The fast development of new radiation therapy techniques led to a common goal: decrease the absorbed dose to healthy tissues without compromising the prescribed target coverage. The only conventional dosimetry is not enough for a comprehensive characterization of clinical radiation beams because the absorbed dose is a macroscopic average quantity, while the biological effects of particles are known to be related to the pattern of radiation interactions in the micrometric scale. DIODE (Diamond Integrated devices fOr haDronthErapy) project deals with the development and test of a novel detection system based on synthetic single crystal diamond able to simultaneously perform dosimetric and microdosimetric characterization of clinical hadron beams. Monte Carlo simulation plays a crucial role in the characterization of these devices. In particular, the Geant4 Monte Carlo toolkit, as it permits to predict response in terms of dosimetric and microdosimetric quantities such as dose to water, mean lineal energy and LET values. Through the comparison between the simulation with the experimental data acquired, it will be possible to understand limits and abilities of those new devices.
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ore 17:00
| Di Palma Roberto (DOTTORATO IN FISICA) | Bayesian determination of the CKM angle gamma and the charm mixing and CPV parameters
Abstract:
We present a Bayesian determination of the CKM angle  and the charm mixing and CP-violating parameters.
We show how considering measurements from both the beauty and the charm sectors improves precision on fit parameters.
The consistency between obtained from tree-level and loop-level processes is discussed. State-of-the-art estimates for the two phases describing CP violation in D mixing are found and debated.
We present future projections for the fit parameters, interpreting their physical impact.
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ore 17:30
| Turchetti Gabriele (DOTTORATO IN FISICA) | Simulation of the radar signal propagation through the crust of Jovian icy moons
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Ph.D. in Physics