# Optimal observable analysis for the decay $b \to s$ plus missing energy

## TL;DR

This paper demonstrates how the decay process $b o s$ with missing energy can be effectively analyzed using optimal observables to explore new physics beyond the Standard Model at future B factories.

## Contribution

It introduces the application of the Optimal Observable technique to the decay $b o s$ plus invisible particles, enabling comprehensive probing of new physics with limited observables.

## Key findings

- Almost the entire parameter space can be probed at high luminosity B factories.
- Different decay channels serve as optimal probes depending on the new physics operator structure.
- The method enhances the sensitivity to new physics beyond current constraints.

## Abstract

The decay $b\to s\nu\bar\nu$ has been a neglected sibling of $b\to s\ell^+\ell^-$ because neutrinos pass undetected and hence the process offers less number of observables. We show how the decay $b\to s~+$~invisible(s) can shed light, even with a limited number of observables, on possible new physics beyond the Standard Model and also show, quantitatively, the reach of future $B$ factories like SuperBelle to uncover such new physics. Depending on the operator structure of new physics, different channels may act as the best possible probe. We show, using the Optimal Observable technique, how almost the entire parameter space allowed till now can successfully be probed at a high luminosity $B$ factory.