Detecting new signals under background mismodelling

Understand

Searches for new astrophysical phenomena often involve several sources of non-random uncertainties which can lead to highly misleading results.

• Among these, model-uncertainty arising from background mismodelling can dramatically compromise the sensitivity of the experiment under study.
• Specifically, overestimating the background distribution in the signal region increases the chances of missing new physics.
• Conversely, underestimating the background outside the signal region leads to an artificially enhanced sensitivity and a higher likelihood of claiming false discoveries.