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CERN experiment discovers five new particles

stfc.ac.uk

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Re: CERN experiment discovers five new particles

#21

Post by nonbel »

inlineint wrote: post #17
nonbel wrote: post #13

Earlier quoted context omitted.

>"it should have been really hard to find something that we don't really know how looks like in such large amount of noise." But if there are thousands of different such "surprising-to find-particles" to possibly detect, is it actually surprising to observe one of them? Edit: Also, from the top answer at your link: "The first generation of elementary particles are by observation not composite and therefore not seen t…

> But if there are thousands of different such "surprising-to find-particles" to possibly detect, is it actually surprising to observe one of them? It is hard to correctly identify what exactly particles from those possible thousands are observed in given data. The are two main problems: the properties of those not yet observed particles are not well known (because it is computationally hard to predict them from the…

Thanks, I missed that "first generation" detail.

Re: CERN experiment discovers five new particles

#22

Post by dukwon »

wolfgke wrote: post #5
brutuscat wrote: post #4

Earlier quoted context omitted.

Professor Tim Gershon, Professor of Physics at University of Warwick and UK spokesperson for the LHCb experiment: “After the LHCb experiment is upgraded in the next long shutdown of the LHC (during 2019-20), it will be able to move to the next stage in the search for new particles: namely, doubly heavy baryons. These states – which contain two charm quarks or two beauty quarks or one of each – have long been predicte…

> Their discovery will help to address important unsolved questions about how hadrons are bound together by the strong interaction. If the particles were already predicted by the standard model, what kind of unsolved questions are to address here, besides validating the predictions of the standard model even further? (serious question)

Since QCD can't be calculated perturbatively at low energy, there are unsolved problems with how to get those predictions in the first place.

Re: CERN experiment discovers five new particles

#23

Post by dukwon »

guitarbill wrote: post #9
teddythetwig wrote: post #2

I assume these particles were already predicted as part of the Standard Model?

AFAIK, the experimentally determined rest masses of these excited states/particles (same thing, different was of looking at it) agree with the calculated ones well. So yes, they were predicted. No surprises sadly; of course it's still a huge achievement!

The theory uncertainties are large. Any measurements within a broad range would also agree with some calculated masses. That doesn't tell you much.

See e.g. https://arxiv.org/abs/1311.4806

Re: CERN experiment discovers five new particles

#24

Post by dukwon »

grabcocque wrote: post #12

I have to admit, I rather admire their putting a brave face on things, with their mildly-too-insistent claim that the LHC is vital for finding new physics despite the increasing likelihood it's not going to find any. In that sense the LHC is a political failure, because it has failed at its primary political job, which is to make the argument for an even bigger collider.

You're jumping the gun a bit there. The general purpose experiments have only collected O(1%) of their eventual datasets.

Re: CERN experiment discovers five new particles

#25

Post by Pharylon »

grabcocque wrote: post #12

I have to admit, I rather admire their putting a brave face on things, with their mildly-too-insistent claim that the LHC is vital for finding new physics despite the increasing likelihood it's not going to find any. In that sense the LHC is a political failure, because it has failed at its primary political job, which is to make the argument for an even bigger collider.

None of that makes any sense.

Re: CERN experiment discovers five new particles

#26

Post by Waterluvian »

shepardrtc wrote: post #18
bpicolo wrote: post #16

Earlier quoted context omitted.

How'd it fail at it's primary task? Wasn't the Higgs a big part of that? Or is the argument that is hasn't found anything outside of the standard model?

It succeeded at its primary task, and the Higgs was a big part of it. Its still doing its job, so give it time. Finding nothing can often be just as important as finding something unexpected.

Mapping an open field fills in just as much paper as if you mapped a busy forest.

I'm not sure what the best way is to convey this idea since people naturally want to find things that are exciting.

Re: CERN experiment discovers five new particles

#27

Post by kuschku »

wolfgke wrote: post #20
shepardrtc wrote: post #18

Earlier quoted context omitted.

It succeeded at its primary task, and the Higgs was a big part of it. Its still doing its job, so give it time. Finding nothing can often be just as important as finding something unexpected.

> Finding nothing can often be just as important as finding something unexpected. From a scientific point you are right. From a political point or the point of securing further funding this statement is (unluckily) wrong.

Not really, the European funding isn’t that relying on new findings.

Re: CERN experiment discovers five new particles

#28

Post by shmageggy »

dukwon wrote: post #24
grabcocque wrote: post #12

I have to admit, I rather admire their putting a brave face on things, with their mildly-too-insistent claim that the LHC is vital for finding new physics despite the increasing likelihood it's not going to find any. In that sense the LHC is a political failure, because it has failed at its primary political job, which is to make the argument for an even bigger collider.

You're jumping the gun a bit there. The general purpose experiments have only collected O(1%) of their eventual datasets.

I know what you intended, but technically O(1%) == O(100%) == O(5000%)

Re: CERN experiment discovers five new particles

#29

Post by quakeguy »

grabcocque wrote: post #14
brutuscat wrote: post #4

Earlier quoted context omitted.

Professor Tim Gershon, Professor of Physics at University of Warwick and UK spokesperson for the LHCb experiment: “After the LHCb experiment is upgraded in the next long shutdown of the LHC (during 2019-20), it will be able to move to the next stage in the search for new particles: namely, doubly heavy baryons. These states – which contain two charm quarks or two beauty quarks or one of each – have long been predicte…

There are a lot of baryons fyi: https://en.wikipedia.org/wiki/List_of_baryons

Math tells me there must be 216, no? 3 quarks make a baryon, there are 6 types of quarks, so 6^3? Idk if up up up baryons are allowed though, or any other baryon made of 3 equal quarks.

Re: CERN experiment discovers five new particles

#30

Post by filmor »

quakeguy wrote: post #29
grabcocque wrote: post #14

Earlier quoted context omitted.

There are a lot of baryons fyi: https://en.wikipedia.org/wiki/List_of_baryons

Math tells me there must be 216, no? 3 quarks make a baryon, there are 6 types of quarks, so 6^3? Idk if up up up baryons are allowed though, or any other baryon made of 3 equal quarks.

They are allowed (https://en.wikipedia.org/wiki/Delta_baryon). Also, you need to take into account the overall spin of the particle (may be either 1/2 or 3/2 depending on whether the quark spins all have the same direction or not) and the individual spins of the constituents. Check https://en.wikipedia.org/wiki/List_of_baryons for details.
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