J. Lovelace Rainbolt | Searcharxiv

arXiv2019

Branching fraction for $Z$ decays to four leptons and constraints on new physics

The LHC experiments have measured the branching fraction for $Z$ decays to four leptons (electrons or muons). We have combined these measurements with the result $\mathcal{B}(Z \to 4\ell) = (4.58 \pm 0.26) \times 10^{-6}$, allowing a precise comparison to the standard model prediction of $(4.70 \pm 0.03) \times 10^{-6}$. We use a minimal extension of the standard model to demonstrate that this combined value may be used to set stringent limits on new physics.

hep-ex↗

arXiv2014

Using Random Forests to Classify W+W- and ttbar Events

We have carried out an exercise in the classification of W+W- and ttbar events as produced in a high-energy proton-proton collider, motivated in part by the current tension between the measured and predicted values of the WW cross section. The performance of the random forest classifier surpasses that of a standard cut-based analysis. Furthermore, the distortion of the distributions of key kinematic event features is relatively slight, suggesting that systematic uncertainties due to modeling might be reduced. Finally, our random forest can tolerate missing features such as missing transverse energy without a severe degradation of its performance.

hep-ex↗