Physicists Discover "Doubly Strange" Particle

Tsalg writes "Physicists have discovered a new particle made of three quarks, the Omega-sub-b. The particle contains two strange quarks and a bottom quark (s-s-b). It is an exotic relative of the much more common proton and weighs about six times the proton mass. This is probably one of the last noticeable sub-atomic discoveries made somewhere else than at CERN since LHC is about to start the hunt for the Higgs particle that remains elusive even for the experiment that just discovered the Omega-sub-b."

Comments

Strange + Bottom ?

[florescent_beige]

Ok I thought quarks, leptons, and neutrinos were grouped like this:

Group 1: quarks; Up & Down, lepton; electron, neutrino; neutrino

Group 2: quarks; Charm & Strange, lepton; muon; neutrino; muon neutrino

Group 3: quarks; Top & Bottom, lepton; tau, neutrino; tau neutrino

So this newly discovered particle is made of quarks from two groups, the strange quark from group 2 and the bottom quark from group 3. Has that been seen before? I never knew it happened.

Re:Strange + Bottom ?

[John Napkintosh]

The article mentions a periodic table of Baryons. I was just checking that out and there are all kinds of combinations that contain quarks from more than one group, and even one that contains one from each of those groups. That doesn't mean they will all be discovered, but it looks like they're well on their way.

The last sentence...

[chr1sb]

...doesn't make sense, not least because TFA notes that 13 out of 20 predicted baryons have been observed, leaving 7 still to be discovered. Surely these will be just as noteworthy as this discovery. Is the LHC the only accelerator capable of creating and observing these remaining baryons?

Also, to nit-pick, TFA states that the Omega-sub-b travels 1 mm in a trillionth of a second. This seems a little high to me, given that c is about 3*10^8 m/s = 3^10^11 mm/s. Rounding errors?

Re:The last sentence...

[Detritus]

Time dilation. Muon decay from cosmic rays is a good example of this.

Re:The last sentence...

[meringuoid]

That puts this particle at about a third of the speed of light.

No it doesn't, I forgot I'd taken the reciprocal. It puts it at about three times the speed of light. I'd guess the other poster is right, then, and that time dilation prolongs its lifetime.

Lamen

[tom17]

OK, so I have been reading a lot about particle physics lately and find the whole subject fascinating, but there is one thing (amongst many things) that I am not quite understanding. I have looked it up and my understanding of particle physics is not "there" yet, or at least not enough to grasp this particular concept. Maybe I have just not read the right explanation.

Can someone in here put it in a simple lamen explanation?

The question is this:

This Omega-sub-b particle contains two strange quarks and a bottom quark and weighs about six times the mass of a proton.
A proton contains 2 up quarks and one down quark.

Strange quarks have a mass of 95MeV, bottom has 4.2GeV so the total mass of the Omega-sub-b would be 4.39GeV
Up quarks have a mass of 3MeV, down has 6MeV so the total mass of a Proton would be 0.012GeV

This would put the Omega-sub-b at 365.8 times the mass of a Proton.

So I am obviously not understanding how the masses of the quarks correlate to the masses of the fermions. What am I missing here?

Thanks,

Tom...

Re:Lamen

[thrich81]

I haven't seen a really suitable answer to your question so I'll give it a try -- I'll use the analogy of protons, neutrons and helium nuclei since they are more familiar. The sum of the masses of two free protons and two free neutrons is larger than the mass of a helium nucleus. The bound combination of the four particles as helium has a lower energy state than the four free particles (due to the attraction they have for each other by the nuclear Strong Force and quantum effects). The difference in the energy states is the "binding energy" of the nucleus, and the nucleus is lighter than the sum of the free particles by the mass-energy equivalence of that binding energy. For composite "particles" such as the proton and this new particle the effect is the same -- the free quarks weigh more than the the composite particle they form with the difference being the mass equivalent of the energy freed up when they bond. In the case of atomic nuclei the mass difference is on the order of a few percent and in the case of the baryons (protons, neutrons, etc.) the mass difference is much, much greater but the basic principle is the same.

Re:Lamen

[Ihlosi]

As a laser physicist... REALLY? Mass deficit from binding energy in molecular bindings or even nuclei is only a small fraction of the total mass.

I would guess that that's the reason why it is so hard to observe quarks. Chemical bindings and nuclear bindings are low-energy enough to mess with on a kitchen table-scale, but if you want to delve into the world of sub-atomic particles you need a honkin' big particle accelerator that consumes a city-equivalent of power.

Re:Excuse Me?

[oldspewey]

Perhaps LHC emits some sort field

In Richard Florida's book Who's your city? he actually gets into various theories about how centers of excellence (whether fashion, IT, finance, science, etc.) tend to create a self-reinforcing "buzz" that draws in more and more talented people, and the intellectual atmosphere and other elements of creative infrastructure then allow those people to achieve at a higher level than they otherwise could.

So according to that theory, yes, the LHC does emit some sort of field ...

static? noise?

[acvh]

They looked at 100 trillion pieces of data, and found 18 that they could call Omega-sub-b. Wouldn't this fall into the realm of randomness?

Been a while since physics class

[Taibhsear]

I was always fascinated by particle physics but it's been a while since I studied it. Can someone explain how a proton-antiproton collision (u,u,d quarks and anti-u,anti-u,anti-d quarks) could produce strange quarks? I thought all that was left after a matter-antimatter collision was x-rays and gamma-rays.

Re:Are quarks real yet?

[m50d]

The same question was asked about electrons before them - after all, they don't behave like point particles (e.g. they diffract). Ultimately, there are no answers - QM is just too divorced from human experience.

They can't be seen or isolated, but we know the reasons why we can't do that. They can only be traced insofar as we observe the particles they make up, like this one. So it's rather like asking whether the electromagnetic field is real - we can't observe it directly, but it simplifies our theories a lot.

Whether that's good enough is up to you. You're never going to be able to separate out a quark and hold it in your hand, but it makes one's life a lot easier to treat it as if it were real, and all the measurements that we can make give the results we would expect if it was real.

Re:Interesting, but

[morgan_greywolf]

And, strangely enough, a strange quark has a strangeness of -1, which to my feeble computer science-trained mind, would seem to indicate that it is not strange! (It actually makes sense when you realize that 'strange quarks' were named before quarks were discovered and that, by definition, the strangeness of a strange anti-particle is +1)

Re:Excuse Me?

[moosesocks]

There's also the funding issue. Largely due to being (mostly) redundant to the LHC, Fermilab's big accelerator, the Tevatron is shutting down next year.