New Beauty Baryon discovered

[Bobbywhy]

New "Beauty Baryon" discovered

“A never-before-seen subatomic particle has popped into existence inside the world's largest atom smasher, bringing physicists a step closer to unraveling the mystery of how matter is put together in the universe.”

“After crashing particles together about 530 trillion times, scientists working on the CMS experiment at Switzerland's Large Hadron Collider (LHC) saw unmistakable evidence for a new type of "beauty baryon."”

http://www.scientificamerican.com/a...-particle-discovered-at-large-hadron-collider

 

[mfb]

I expect that the large LHC datasets have the potential for some more particles. However, as they are not fundamental particles and as they are predicted by theoriy, this is not really amazing.
The hard part is not to find these particle, but to evaluate their properties.

 

[lpetrich]

I went over to the Particle Data Group, to see what hadron states we've discovered so far.

We've reliably detected no hadrons with more than three (anti)quarks, and top quarks decay too fast to be hadronized, so we have only the other 5 flavors of quarks in a hadron.

Of mesons, we've detected every flavor combination, while of the baryons, we've detected every flavor combination only of up, down, and strange: uuu, uud, udd, ddd, uus, uds, dds, uss, dss, sss. We've also found every combination with a single charm quark: uuc, udc, ddc, usc, dsc, ssc. However, we've found only some with a single bottom quark: uuc, udc, ddc, usc, dsc, and ssc, but we've detected only some of those combinations with single-bottom baryons: udb, usb, dsb, and ssb. That leaves uub and ddb.

But I would not be surprised if the LHC detector teams also discover evidence of uub and ddb baryons in LHC events.

I don't know if there is much prospect of detecting baryons with multiple charm and/or bottom quarks, however. The PDG's summary tables mention a $\Xi_{cc}^{+}$ (dcc) baryon, but with only one star, meaning a dubious detection.

 

[mfb]

Well, this is related to their production and (to a lesser extent) to their detection.

Light quarks (uds) don't need much energy to be produced, they appear in large amounts everywhere in high-energy collisions. Charm and bottom pair production is less frequent, and the quarks are produced with higher energy. While hadrons with a single heavy quark can be produced out of the quarks in these pairs, hadrons with two heavy quarks need the production of (usually) two pairs in the same collision, and with a similar energy and direction in order to get into the same baryon.

There should be an LHCb paper or conference report on double-charm production (two charm and two anti-charm quarks), but its focus was on mesons and not baryons.
Edit: Here it isMore than one heavy quark gives a lot of different possible decay modes and usually a short lifetime. Both can make it harder to detect, compared to other baryons.