- Search for heavy neutrinos in $D_s$ decays with the CMS detector at LHC
- Lunerti, Leonardo <1995>
Subject
- FIS/01 Fisica sperimentale
Description
- This thesis presents a search for a sterile right-handed neutrino $N$ produced in $D_s$ meson decays, using proton-proton collisions collected by the CMS experiment at the LHC. The data set used for the analysis, the B-Parking data set, corresponds to an integrated luminosity of $41.7\,\textrm{fb}^{-1}$ and was collected during the 2018 data-taking period. The analysis is targeting the $D_s^+\rightarrow N(\rightarrow\mu^{\pm}\pi^{\mp})\mu^{+}$ decays, where the final state muons can have the same electric charge allowing for a lepton flavor violating decay. To separate signal from background, a cut-based analysis is optimized using requirements on the sterile neutrino vertex displacement, muon and pion impact parameter, and impact parameter significance. The expected limit on the active-sterile neutrino mixing matrix parameter $|V_{\mu}|^2$ is extracted by performing a fit of the $\mu\pi$ invariant mass spectrum for two sterile neutrino mass hypotheses, 1.0 and 1.5 GeV. The analysis is currently blinded, following the internal CMS review process. The expected limit ranges between approximately $10^{-4}$ for a 1.0 GeV neutrino to $7\times10^{-5}$ for a 1.5 GeV neutrino. This is competitive with the best existing results from collider experiments over the same mass range.
Date
- 2023-06-15
Type
- Doctoral Thesis
- PeerReviewed
Format
- application/pdf
Identifier
urn:nbn:it:unibo-29706
Lunerti, Leonardo (2023) Search for heavy neutrinos in $D_s$ decays with the CMS detector at LHC, [Dissertation thesis], Alma Mater Studiorum Università di Bologna. Dottorato di ricerca in Fisica