Science CERN: LHCb Announces a Charming New Particle

[Nicholas Kang]

CERN: LHCb announces a charming new particle

BBC: LHC double heavy particle to shine light on strong force

Image representing the new particle observed by LHCb, containing two charm quarks and one up quark. (Image: Daniel Dominguez/CERN)

*The collaboration has submitted a paper reporting these findings to the journal Physical Review Letters.

Today at the EPS Conference on High Energy Physics in Venice, the LHCb experiment at CERN’s Large Hadron Collider has reported the observation of Ξcc++(Xicc++) a new particle containing two charm quarks and one up quark. The existence of this particle from the baryon family was expected by current theories, but physicists have been looking for such baryons with two heavy quarks for many years. The mass of the newly identified particle is about 3621 MeV, which is almost four times heavier than the most familiar baryon, the proton, a property that arises from its doubly charmed quark content. It is the first time that such a particle has been unambiguously detected.

The research team will now measure the properties of the Xi-cc++ to establish how this new arrangement of quarks behaves and how the strong force holds the system together. They also expect to find more double heavy quark particles.

Another unusual property of the particle is that it has two positive charges double that of the proton and it is four times heavier.

 

[RisingFury]

Wow, interesting.

Ok, so a particle made up of three quarks is called a Baryon. We know a bunch of them already, but protons and neutrons are more commonly known.

Each quark has a spin of 1/2, so having three quarks leaves you with two options for the total spin of the particle:
1/2 + 1/2 + 1/2 = 3/2
or
1/2 - 1/2 + 1/2 = 1/2

But along with spin, each quark also contributes electric charge. Up, charm and top quarks have a charge of 2/3 and down, strange and bottom quarks have a charge of -1/3, so this charm-charm-up particle has a charge of
2/3 + 2/3 + 2/3 = 6/3 = 2

So the charge is positive, like a proton, but a proton is made up of up-up-down, so
2/3 + 2/3 - 1/2 = 1

 

[Notebook]

Pentaquarks: scientists find new "exotic" configurations of quarks

They hope they will help us understand the "strong force" that holds the insides of atoms together.

www.bbc.com