Post

Hadron number 80 has dropped!

CERN@cern.bsky.social

The LHCb Collaboration discovers new proton-like particle Composed of two charm quarks and one down quark, the doubly charmed particle is four times heavier than a proton. Find out more: home.cern/news/news/ex...

Patrick Koppenburg 🐧

@koppenburg.ch

17 Mar

This one is special. There are only two weakly decaying new hadrons found at the LHC. The other one is the doubly charged partner of the newly observed Ξcc⁺. That makes a pretty boring plot. All the other ones are at www.koppenburg.ch/particles.html

Patrick Koppenburg 🐧

@koppenburg.ch

17 Mar

The Ξcc⁺ was already "discovered" by the SELEX experiment at Fermilab in 2002. However at a mass that is at odds with predictions and with the mass of the doubly charged Ξcc⁺⁺. I don't know what they have seen , but it's not the Ξcc⁺.

Patrick Koppenburg 🐧

@koppenburg.ch

More context: bsky.app/profile/fitz...

Conor Fitzpatrick@fitzparticle.bsky.social

Xi_cc+ in the Guardian, noting that cuts from @ukri.org will prevent future discoveries like this.

17/3/26, 8:41 am0 reposts3 likes

Patrick Koppenburg 🐧

@koppenburg.ch

31 Mar

The paper is out bsky.app/profile/lhcb...

LHCb Experiment@lhcb.bsky.social

Observation of the doubly charmed baryon Ξcc⁺ with the LHCb Run 3 detector - The Ξ+cc mass is measured to be 3619.97±0.83±0.26+1.90−1.30MeV, where the third uncertainty is due to the unknown lifetime, which is assumed to lie in the range 15-160 fs. arxiv.org/abs/2603.28456