# Observation of a new Bs π state

- Institution: CERN
- Department: EP Seminar
- Speaker: Alexey Drutskoy
- Year: 2016
- Language: English
- Source: [CERN](https://videos.cern.ch/record/3011871)
- Licence: [CERN](http://copyright.web.cern.ch)
- Who can watch: Teens profiles and older (sources give no ratings; placed by Invisible Network from the source's own words)

We report the observation of a narrow structure, X(5568), in the decay sequence X(5568) → Bs π±, Bs → J/ψ ϕ, J/ψ → μ+μ−, ϕ → K+K−. This is the first observation of a hadronic state with valence quarks of four different flavors. The mass and natural width of the new state are measured to be m = 5567.8 ± 2.9 (stat) +0.9−1.9 (syst) MeV and Γ = 21.9 ± 6.4 (stat) +5.0−2.5 (syst) MeV, and the significance including look-elsewhere effect and systematic uncertainties is 5.1σ. The observation is based on10.4 fb−1 of ppbar collision data at 1.96 TeV collected by the D0 experiment at the Fermilab Tevatron collider. .

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## Lectures

1. [Observation of a new Bs π state](https://invisiblenetwork.ai/learn/cern/3011871/4d51ec983ca9), 1 h 20 min (CERN's player)