Contributor info: Dr Andreas Crivellin

Benjamin Lieberman, Salah-Eddine Dahbi, Andreas Crivellin, Finn Stevenson, Nidhi Tripathi, Mukesh Kumar, Bruce Mellado

SciPost Phys. Core 7, 073 (2024) · published 13 November 2024 | Toggle abstract · pdf

To mitigate the model dependencies of searches for new narrow resonances at the Large Hadron Collider (LHC), semi-supervised Neural Networks (NNs) can be used. Unlike fully supervised classifiers these models introduce an additional look-elsewhere effect in the process of optimising thresholds on the response distribution. We perform a frequentist study to quantify this effect, in the form of a trials factor. As an example, we consider simulated $Z\gamma$ data to perform narrow resonance searches using semi-supervised NN classifiers. The results from this analysis provide substantiation that the look-elsewhere effect induced by the semi-supervised NN is under control.

Vincenzo Cirigliano, Andreas Crivellin, Martin Hoferichter

SciPost Phys. Proc. 1, 007 (2019) · published 18 February 2019 | Toggle abstract · pdf

A new tensor interaction is the only possibility to explain the $2.8\sigma$ tension observed by the BaBar collaboration in the CP asymmetry in $\tau\to K_S\pi\nu_\tau$ with physics beyond the Standard Model (BSM) realized above the electroweak scale. However, the strong phase generated by the interference between vector and tensor phases is suppressed by at least two orders of magnitude due to Watson's final-state-interaction theorem, and the strength of the CP-violating tensor interaction is strongly constrained by bounds from the neutron electric dipole moment and $D$-$\bar{D}$ mixing. As a result, a confirmation of the tension at Belle II would point to light BSM physics.