Particle Physics Seminar

First observation and branching fraction measurement of the Σ⁺ → pμ⁺μ⁻ decay at LHCb

by Dr Gabriele Martelli (Universität Perugia)

Europe/Berlin
CP-03-123 (TU Dortmund)

CP-03-123

TU Dortmund

Description

The Σ⁺ → pμ⁺μ⁻ decay is observed for the first time at the LHCb experiment using proton-proton collision data corresponding to an integrated luminosity of 5.4 fb⁻¹ at a centre-of-mass energy of 13 TeV. This flavour-changing neutral current process is highly suppressed in the Standard Model and sensitive to potential contributions from physics beyond the Standard Model, such as new mediators or short-distance dynamics. In particular the HyperCP experiment years ago presented an evidence of this decay with a hint of a possible unknown intermediate particle. This was excluded by LHCb already in 2018. The new measurement presents a highly significant observation and a measurement of its integrated branching fraction and dimuon invariant mass distribution. This is the rarest baryon decay ever observed.

The start of the seminar has been postponed to 13:30.

Zoom link

Organised by

Maik Becker & Serena Maccolini