8-1-2022

Thesis

M.S. in Physics

Jake V. Bennett

Gavin Davies

Alakabha Datta

#### School

University of Mississippi

#### Relational Format

dissertation/thesis

#### Abstract

Using data collected by the Belle II experiment at the SuperKEKB asymmetric-energy e+e- collider, a measurement of the branching fraction for inclusive $\Upsilon(4S)$ decays to $\Upsilon(1S)$, where $\Upsilon(1S)$ decays to $\mu^{+}\mu^{-}$, is investigated. A similar study has not been conducted for decades. Such an inclusive measurement may be compared to the sum of exclusive branching fractions in order to check the completeness of the known exclusive decays. A disparity between the measured exclusive decays and the inclusive measurement would be suggestive of additional decay modes that are accessible beyond naive expectations. This analysis is further extended to include measurements of the branching fraction for inclusive $\Upsilon(4S)$ decays to $\Upsilon(3S)$ and $\Upsilon(2S)$. Furthermore, this study, as well as measurements of the $\Upsilon(3S)$, $\Upsilon(2S)$ and $\Upsilon(1S)$, can be extended to data collected at 10.75 GeV to explore inclusive decays to $\Upsilon$ states to allow for elucidation of the mysterious $\Upsilon(10750)$ state.

COinS