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arXiv · 2405.09974

Tau and low multiplicity physics at Belle and Belle II

Luigi Corona
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Abstract

The Belle and Belle II experiments have collected a 1.4 ab$^{-1}$ sample of $e^+e^-$ collision data at centre-of-mass energies near the $\Upsilon (nS)$ resonances, of which 424 fb$^{-1}$ were collected at Belle II in Run1 (2019--2022). We present a measurement of the lepton-flavour universality between electrons and muons, the search for the lepton-flavour violation decay $\tau^{-} \to \mu^{-}\mu^{+}\mu^{-}$, and a measurement of the $e^+e^- \to \pi^+\pi^-\pi^0$ cross section in the energy range from 0.62--3.5 GeV using an initial-state radiation technique, all performed with Belle II data.

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Luigi Corona. 2024-05-16. Tau and low multiplicity physics at Belle and Belle II. https://arxiv.org/abs/2405.09974

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