iiinova — where your digital self keeps evolving

Patrick Koppenburg 🐧 @koppenburg.ch · 24/09/2026

LHCb @lhcb.social.bsky says YES ! We report the observation of a narrow particle decaying to a Bs meson and a neutral pion. The exact same thing but with a beauty quark replacing the charm quark. arxiv.org/abs/2609.25178

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Patrick Koppenburg 🐧 @koppenburg.ch · 24/09/2026

Quantum mechanics doesn't like that and prevents it by making it long lived. Well, it's 10⁻²² seconds "long", but that's 10 times more than usual strong decays. Experimentally what you see is that the peak is rather narrow.

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Patrick Koppenburg 🐧 @koppenburg.ch · 24/09/2026

And in Summer Belle reported the quantum properties of the two particles arxiv.org/abs/hep-ex/0... and arxiv.org/abs/hep-ex/0... .

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Patrick Koppenburg 🐧 @koppenburg.ch · 24/09/2026

Things went very fast. A week later the CLEO experiment confirmed the particle at 2317 MeV and also that at 2460. arxiv.org/abs/hep-ex/0...

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Patrick Koppenburg 🐧 @koppenburg.ch · 24/09/2026

They also saw a peak in the combination of a Bs meson, a pion and a photon, but were unsure what it was.

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Patrick Koppenburg 🐧 @koppenburg.ch · 24/09/2026

A bit of history of particle physics that takes an unexpected turn today. In 2003 the BaBar experiment at SLAC reported a particle decaying to a Ds meson and a neutral pion, with a mass of 2317 MeV. arxiv.org/abs/hep-ex/0...

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Patrick Koppenburg 🐧 @koppenburg.ch · 23/09/2026

I grew up in a city that starts at 370m above sea level and reaches more than 700m. From any point you see the lake and the mountains in the South. How can you live in a place that is so flat you can't tell any direction? Really scary.

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Patrick Koppenburg 🐧 @koppenburg.ch · 23/09/2026

Avec l'AI il faut poser des questions comme à un humain. Bizarrement Cluade et Gemini n'ont pas les mêmes goûts littéraires.

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Patrick Koppenburg 🐧 @koppenburg.ch · 22/09/2026

C'est quoi ce dictionnaire ? 😬 Le bon échoué bien demain. Le bon échalotes bien demain. Le bon échouer bien demain.

il échoit bien demain. échoit n'est pas reconnu.

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Patrick Koppenburg 🐧 @koppenburg.ch · 21/09/2026

But what about the baryon with three charm quarks? Quantum mechanics forces it to have spin 3/2, and thus it is in another multiplet. The Ωccc⁺⁺ is probably already there in the data, but too rare to be seen. We will likely need the second upgrade of the LHCb detector to see it. /end

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Patrick Koppenburg 🐧 @koppenburg.ch · 21/09/2026

Here's the completed multiplet as a model.

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Patrick Koppenburg 🐧 @koppenburg.ch · 21/09/2026

The observation was made using 2024 data collected by the upgraded LHCb detector.

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Patrick Koppenburg 🐧 @koppenburg.ch · 21/09/2026

Then came the singly charged one earlier this year, and finally the Ωcc⁺ now, with two charm quarks and two strange quarks. The particle appears as a clear excess over the background in a mass plot.

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Patrick Koppenburg 🐧 @koppenburg.ch · 21/09/2026

The first floor was completed in the eighties. The doubly charmed baryons in second floor were all discovered by the LHCb experiment, starting with the doubly charged Ξcc⁺⁺ ("Xi-cc-plus-plus") in 2017.

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Patrick Koppenburg 🐧 @koppenburg.ch · 21/09/2026

What if one adds the charm quark, discovered in 1974? One gets more complicated diagrams. The baryon multiplet we know is at the base, and there's a first floor with one charm quark and a second with two.

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Patrick Koppenburg 🐧 @koppenburg.ch · 21/09/2026

That was for spin-1/2 baryons. If one looks at spin-3/2, where the three quarks have all their spin aligned, more possibilities are allowed. At the very bottom the is the Ω baryon "omega" with three quarks, discovered in 1964.

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Patrick Koppenburg 🐧 @koppenburg.ch · 21/09/2026

The same applies for baryons, this time with three quarks. There's a similar one for anti-baryons. The neutron and proton are at the top. All other particles have one or two strange quarks.

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Patrick Koppenburg 🐧 @koppenburg.ch · 21/09/2026

This scheme explained all mesons known at the time as pairs of a quark and an antiquark for all possibilities of up, down and strange quarks. There are 8 possibilities for up, down and strange quarks and antiquarks. Gell-Mann called this the Eightfold way.

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Patrick Koppenburg 🐧 @koppenburg.ch · 21/09/2026

In 1964 Gell-Mann, Zweig, and Petermann simultaneously proposed that the particles known at the time (barring the electron and the muon) were composite and made of a quark and an antiquark (mesons) or three quarks (baryons).

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Patrick Koppenburg 🐧 @koppenburg.ch · 05/09/2026

Oh! Before and after app update. 😍

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Patrick Koppenburg 🐧 @koppenburg.ch · 05/09/2026

Sent on 31 July in Edinburgh. Arrived today. @royal-mail.bsky.social is about half the speed of the Roman Cursus Publicus 2000 years ago.

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Patrick Koppenburg 🐧 @koppenburg.ch · 25/08/2026

Pas de triche. Partagez la dernière photo de votre appareil photo. (Quelques essais de mon nouveau pocket pour la montagne)

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Patrick Koppenburg 🐧 @koppenburg.ch · 24/08/2026

Binary date of birth? I don't think any applies to me.

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Patrick Koppenburg 🐧 @koppenburg.ch · 16/08/2026

Ooops. My local newspaper picked a random image of an eclipse as illustration. 🙄

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Patrick Koppenburg 🐧 @koppenburg.ch · 09/08/2026

😂 I was in Namibia in 2009 too.

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Patrick Koppenburg 🐧 @koppenburg.ch · 09/08/2026

That's how it was 20 years ago (also one of my fav pics)

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Patrick Koppenburg 🐧 @koppenburg.ch · 08/08/2026

Helping at the Nyon triathlon. World university championships.

triathletes out of the water running to the bikes

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Patrick Koppenburg 🐧 @koppenburg.ch · 07/08/2026

That's not how I remember Bristol

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Patrick Koppenburg 🐧 @koppenburg.ch · 06/08/2026

C'est la guette. Il a sonné 10. Il a sonné 10. #lausanne

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Patrick Koppenburg 🐧 @koppenburg.ch · 04/08/2026

I guess it's the "pulse" that got me this invitation. #predatoryConference

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Patrick Koppenburg 🐧 @koppenburg.ch · 29/07/2026

Final readings of @lhcb.bsky.social papers: we have 7 papers these two weeks. And that's not yet counting the new results that will be shown at ICHEP. #LHCbEditorialBoard

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Patrick Koppenburg 🐧 @koppenburg.ch · 14/07/2026

Bjarne Stroustrup at CERN. The main Auditorium is packed.

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Patrick Koppenburg 🐧 @koppenburg.ch · 01/07/2026

Come uptown to the festival de la cité

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