Characterization of the Timing Properties of the SuperNEMO Demonstrator. Extraction of the SuperNEMO Sensitivity to the Axial-Vector Coupling Constant

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A90107%2F22%3A00381589" target="_blank" >RIV/68407700:90107/22:00381589 - isvavai.cz</a>

Result on the web

<a href="https://theses.fr/2022UPASP086" target="_blank" >https://theses.fr/2022UPASP086</a>

DOI - Digital Object Identifier

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Result language

angličtina

Original language name

Characterization of the Timing Properties of the SuperNEMO Demonstrator. Extraction of the SuperNEMO Sensitivity to the Axial-Vector Coupling Constant

Original language description

Neutrinoless double-beta decay (0νββ) is a hypothetical radioactive decay beyond the Standard Model, characterized by the violation of the leptonic number through the emission of two electrons and no electron anti-neutrinos. The SuperNEMO experiment is designed to search for this decay. Its exclusion sensitivity is 10(2)⁶ years on the 0νββ half-life, corresponding to an effective Majorana mass at < 40-100 meV. For the correct performance of the detector, a timing study of the calorimeter has been performed. The calorimeter has been calibrated in time and the time resolution has been extracted for each optical module using dedicated data taking runs with a ⁶⁰Co source placed behind the calorimeter. The ⁶⁰Co source emits two gammas (almost) simultaneously and the detection is performed by finding coincidences between the different optical modules. The time calibration reached a precision of <~ 0.2 ns, sufficient to perform background rejection using time of flight calculations. The mean time resolution for 8" photomultipliers of the main walls is found to be 0.619 ± 0.002 (stat) + 0.049 (sys) - 0.004 (sys) for gammas at 1 MeV. The 0νββ decay rate depends strongly on the axial-vector coupling constant g_A, and constraining of this constant is crucial to estimate accurately this rate. More accurate theoretical calculations of the double beta decay allowed by the standard model have led to new dependencies of the rate on phase space factors with different kinematics. Therefore, an accurate measurement of the energy of each electron can constrain the axial-vector coupling constant. The sensitivity of SuperNEMO to the quenching of the axial-vector coupling constant has been studied using simulated data in the SuperNEMO environment. After introducing the physics of neutrinos and double-beta decays, and in details the SuperNEMO experiment, I present the detailed work performed to extract the time resolution and calibrate in time the SuperNEMO calorimeter, and the analysis to find the sensitivity of SuperNEMO to the quenching of the axial-vector coupling constant g_A.

Czech name

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Czech description

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Type

O - Miscellaneous

CEP classification

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OECD FORD branch

10304 - Nuclear physics

Project

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Continuities

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Publication year

2022

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů