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Pentaquarks

Bikewer

Penultimate Amazing
Bikewer
Joined
Sep 12, 2003
Messages
13,242
Location
St. Louis, Mo.
Thought one of our physics guys would have posted on this by now....:
http://www.smithsonianmag.com/smart-news/what-heck-pentaquark-180955942/

Evidently this particular combination of 5 quarks has been hypothesized for many years, but never observed.
The Large Hadron Collider has provided proof of the configuration.

Now, quarks are strange (cough, cough) enough they have their charms and I'm sure one of our more physics-oriented members can explain more.
 
Bikewer said:
Thought one of our physics guys would have posted on this by now....:
http://www.smithsonianmag.com/smart-news/what-heck-pentaquark-180955942/

Evidently this particular combination of 5 quarks has been hypothesized for many years, but never observed.
The Large Hadron Collider has provided proof of the configuration.

Now, quarks are strange (cough, cough) enough they have their charms and I'm sure one of our more physics-oriented members can explain more.
Click to expand...
Those puns were a little over the top. You're veering down; pull up before you hit rock bottom.
 
Hopefully one or more of the physics people will!!! Thanks for getting it here fast though!!!!
 
http://home.web.cern.ch/about/updates/2015/07/discovery-new-class-particles-lhc
Brief
http://press.web.cern.ch/press-rele...ports-observation-exotic-pentaquark-particles
full


LHCb researchers looked for pentaquark states by examining the decay of a baryon known as Λb (Lambda b) into three other particles, a J/ψ- (J-psi), a proton and a charged kaon. Studying the spectrum of masses of the J/ψ and the proton revealed that intermediate states were sometimes involved in their production. These have been named Pc(4450)+ and Pc(4380)+, the former being clearly visible as a peak in the data, with the latter being required to describe the data fully.

“Benefitting from the large data set provided by the LHC, and the excellent precision of our detector, we have examined all possibilities for these signals, and conclude that they can only be explained by pentaquark states”, says LHCb physicist Tomasz Skwarnicki of Syracuse University.

"More precisely the states must be formed of two up quarks, one down quark, one charm quark and one anti-charm quark.”
Click to expand...
 
Lennart Hyland said:
Maybe a stupid question but have quarks been observed physicaly? And if how does that experiment work?
Click to expand...

They can't be- far below the ability of our best instruments (and likely always will be) to allow us to see them. As with all the particles in that unimaginably (for most) tiny range , instruments cannot resolve anything that small. WE may, though, see the results of passage or collision - the way we have verified the larger particles they make up (which we also will not likely ever see directly). The question is not stupid (many, though not all, questions are not). The basic way of spotting particles is jamming small particles together at VERY high speeds in an accelerator (like at CERN) and recording the results as trails left from the collision. AS we have others at much higher paygrades than I here, I trust one or more will explain the detail and correct any misleading statements I may have made - but I am pretty sure this covers the basics.
 
Lennart Hyland said:
Maybe a stupid question but have quarks been observed physicaly? And if how does that experiment work?
Click to expand...

Quarks are never seen as individual particles. So far they have only been observed in triplets, making up baryons, and pairs, making up mesons. The pentaquark is another theoretical configuration that we have now found more evidence for. Examples of baryons are the proton and the neutron. Some baryons, especially the proton are very stable, whereas all mesons decay very quickly.

Stable baryons, the nucleons really, can be probed for their internal structure. Such experiments bombard the nucleons with electrons and the deflection of the electrons is measured. This way we are able to 'see' that, for example, the proton is made up of three quarks. The principle of these experiments is similar to the famous Rutherford experiment in which he probed the internal structure of the atom, but they are looking at much smaller structures.

The other way of learning about quarks is by observing hadrons (the name for baryons and mesons). Unusual baryons (i.e. something other then protons and neutrons) and mesons are created in high-energy collisions of hadrons. This is what the LHC at CERN does. The detectors at the LHC and similar facilities can measure the momentum, electric charge, spin, etc. of these particles. From this data, we can infer knowledge about the various types of quarks and how they combine to form hadrons.
 
Just another invented discovery to weakly justify their giant electricity bill and the paychecks of thousands of people. It is perfect. The ultimate sham---- WOW!!!

There will be more invented particles on the way. Just wait until they want to make the LHC even bigger. They will dig into some outdated 1960's "physics" papers and go, "hey we predicted this! Look! We're not absolutely full of ****** You gotta believe us!"

I thought this crowd was comprised of actual skeptics? Irony at its finest.
 
Roboramma said:
I'm having trouble parsing this sentence, can you restate it?
Click to expand...

I hope I am wrong, but it quite much sounds like W is saying that attributes of quanta can be randomly attributed to any given quanta without regard to actual attributes solidly established and verified for same. Which, if it indeed is what Wolrab claims , is completely wrong.
 
jeffreyw said:
Just another invented discovery to weakly justify their giant electricity bill and the paychecks of thousands of people. It is perfect. The ultimate sham---- WOW!!!

There will be more invented particles on the way. Just wait until they want to make the LHC even bigger. They will dig into some outdated 1960's "physics" papers and go, "hey we predicted this! Look! We're not absolutely full of ****** You gotta believe us!"

I thought this crowd was comprised of actual skeptics? Irony at its finest.
Click to expand...

And essentially the same for this one. I am forced to assume that a century ago the persons referred to (Wolrab and jeffreyw) would have been all fired up at the idiots who thought heavier -than-air flight was possible and were working on it and those who believed rockets could never work in space as there was nothing to push against there. Just look at all the money wasted trying for those impossible things.....Oh, wait, we have them and they work just fine!!!
 
I wonder what is the point of this? I know it has employed a lot of highly intelligent people, used a lot of valuable resources. So what is the payoff? Have other LHCs provided one for example?
 
rjh01 said:
I wonder what is the point of this? I know it has employed a lot of highly intelligent people, used a lot of valuable resources. So what is the payoff? Have other LHCs provided one for example?
Click to expand...

What was the point of Newton's work? Einstein's work? Lord Kelvin's work?

Theoretical science does not have a "payoff" other than knowledge. However, knowledge can often be later applied to practical uses - for example, quantum physics was, originally, of no practical use. It is now being used in the design of electronics, and cutting-edge research in quantum computing is a hot topic.
 
rjh01 said:
I wonder what is the point of this? I know it has employed a lot of highly intelligent people, used a lot of valuable resources. So what is the payoff? Have other LHCs provided one for example?
Click to expand...

Some evidence for pentaquarks has been offered by other experiments since at least the 2000s. However, this data has turned out to be inconclusive at best. The results from CERN's LHCb detectors are by far the best so far, providing very good evidence for the existence of these particles.

However, the experiment that provided the data was not designed to look for pentaquarks. Instead its purpose is to create large numbers of b-mesons (hadrons containing bottom quarks). Studying b-mesons is a way of examining the CP-violation. Understanding CP-violation seems to be key to explaining why there is so much more matter than antimatter in our universe.

The data on the pentaquarks should be useful to better understand quarks in general. It might also improve our understanding of the strong interaction, the force that confines quarks to hadrons and keeps nuclei together.
 
jeffreyw said:
Just another invented discovery to weakly justify their giant electricity bill
Click to expand...

CERN uses approximately 1.3 TWh per year, corresponding to the energy needs of about 300.000 houses. This is however a fairly modest energy use when compared to some large industrial installations. For example, Rio Tinto's Dunkerque aluminum smelter uses three times as much energy. Total yearly electric energy production in France is about 560 TWh.
 
jeffreyw said:
Just another invented discovery to weakly justify their giant electricity bill and the paychecks of thousands of people. It is perfect. The ultimate sham---- WOW!!!

There will be more invented particles on the way. Just wait until they want to make the LHC even bigger. They will dig into some outdated 1960's "physics" papers and go, "hey we predicted this! Look! We're not absolutely full of ****** You gotta believe us!"

I thought this crowd was comprised of actual skeptics? Irony at its finest.
Click to expand...
Let's restate the hypotheses:

1) 10s of 1000s of scientists, engineers, software developers, scientific journal editors --who come from every nation on the planet --collaborate on the largest organized scientific experiments in history.

2) For decades, 10s of 1000s of those same people are secret participants in a worldwide conspiracy of evil atheist scientists who want to trick the world into believing in Stephen Hawking for some reason.

What would Occam say?
 
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