Master Thesis Open Access
Heidelbach, Alexander
{ "@context": "https://schema.org/", "@type": "ScholarlyArticle", "contributor": [], "creator": [ { "@type": "Person", "affiliation": "KIT/ETP", "name": "Heidelbach, Alexander" } ], "datePublished": "2022-04-28", "description": "<p>In a set of simple extensions of the Standard Model, Axion Like Particles (ALPs) arise as pseudo Nambu-Goldstone bosons of theories with a spontaneously broken Peccei-Quinn symmetry that is anomalous under the Standard Model gauge symmetry. Due to constraints in flavour-changing current (FCNC) processes, involving the coupling of ALPs directly to Standard Model fermions and gluons, direct couplings of ALPs to the electroweak gauge bosons are particularly interesting. As a result of a coupling to $W$ bosons, ALPs can emerge in FCNC $b\\to s$ transitions. Depending on the ALP mass and the coupling strength to photons a possible experimental signature is $B^{\\pm}\\to K^{\\pm}a, a\\to\\gamma\\gamma$ with long lived ALP decays. This thesis performs a sensitivity study in the search for the $B^{\\pm}\\to K^{\\pm}a, a\\to\\gamma\\gamma$ signature based on Belle II simulation samples corresponding to an integrated luminosity of 100\\,fb$^{-1}$. The sensitivity study includes an optimised candidate selection and signal yield scans of the invariant di-photon mass distribution in the range of $0.175\\,\\text{GeV/c}^2$ to $4.600\\,\\text{GeV/c}^2$ for eight different ALP lifetimes between $0\\,\\text{cm}$ and $50\\,\\text{cm}$. Resulting expected limits are comparable to a similar search for $B^{\\pm}\\to K^{\\pm}a, a\\to\\gamma\\gamma$ on data collected by the BABAR experiment. </p>", "headline": "Sensitivity Study in the Search for $B^{\\pm}\\to K^{\\pm}a$ (displaced $a\\to\\gamma\\gamma$) Decays at Belle II", "image": "https://publish.etp.kit.edu/static/img/logos/zenodo-gradient-round.svg", "inLanguage": { "@type": "Language", "alternateName": "eng", "name": "English" }, "keywords": [ "Belle II", "Analysis", "Search for New Physics", "ALPs" ], "name": "Sensitivity Study in the Search for $B^{\\pm}\\to K^{\\pm}a$ (displaced $a\\to\\gamma\\gamma$) Decays at Belle II", "url": "https://publish.etp.kit.edu/record/22123" }