Quark Strangeness and Yarn

Hello. This has strong ties with "Gauge this", but nothing is repeated, just reinforced.

Quark.

Armin Shimmerman? No.

I refer to the little people inside everything.

Here is what we have so far - - -

Atoms > > Nuclei > > protons and neutrons > > quarks?

What are they?

To illustrate, a potted history would help.

The Geeks, sorry, Greeks (bless 'em) figured out that stuff is made of smaller stuff.

They called them "atoms" and thought by reasoning alone, that nothing could be smaller. They were wrong.

Then John Dalton came along in the eighteenth century (didn't take THAT long, did it?) and did a bit more work on the idea, and came up with "elements".

There are 92 of these in nature, and what came about was that these "atoms" were not indivisible at all. Earnest Rutherford showed that by splitting them.

It turned out that they were made up of tinier bits which we called "electrons" and "protons". It took a while (until 1932 actually) to work out that there was another in there also (the "neutron"), but basically we thought we had the atom sussed.

What came about next was a mixture of conjugation and speculature ("conspecularity" if you like).

If protons were all the same electrical charge, and they were all packed together tightly in the nucleus, how come all atoms never flew apart ( a few do by themselves - this is called "radioactivity").

Think about it.

The only possible answer we could give was that there was another "force" stronger than electrostatics, but only available at very short distances ( a bit like two very passionate lovers )

To be picturesque, if I held a proton in each hand ( let's just say they were the size of tennis balls ), and tried to bring them together, I would feel an enormous force trying to keep them apart. This is called "electrostatic repulsion".

At some point, though, if I was strong enough, when these tennis balls were, say, 6cm apart, they would snap together as if there was an elastic band between them. This is called "the strong force".

Back to reality, then. This "strong force" (scientists are not heavily overvocabulariated) pulls the protons together inside the nucleus, despite the electrostatic process which asks them to go away.

But the end is NOT nigh.

It was established in the 1960's that this type of "strong" force was only a mere shadow of the strength of the "true nature of the Force" (see my post with the same title).

Okay, history lesson over.

The present case is this:

We now know that protons and neutrons are comprised of quarks. (See "three jets are better than two"). Electrons seem to have no structure at all (They may as well not be there). These quarks appear to act like electrons BUT we can never see one, simply because of this seeming cop-out of the very short range of the strong force. They remain inside the protons and neutrons and cannot get out.

They are constrained in a manner that is not unlike an elastic band.

Without going into further details, it will be sufficient to point out that it is like "electrostatic charge", but with not two but three different types of "charge".

They are called "red", "green", and "blue" (physicists are the World's Worst nomenclaturists (- apart from chemists, that is. I mean, who has ever heard of "1-bromo 3-dichloro 4-iodo pentane" for crying out loud???)

Anyway, back to the point, because this is what these "quarks" act like - points. The way of thinking now is that we imagine that inside the proton is a space as big as the earth. The three quarks in the proton will be smaller than a grain of sand each. They are free to roam, but can never get out. This is called "ultra-violet freedom".

BUT because of our quest to find the GUT (See my post "That GUT feeling"), the theory goes like this: If the quarks ever get close enough to shake hands (and we are talking two grains of sand in a container the size of the earth here), the WEAK force will assert itself and change one of them by exchanging one of the vector bosons, and the proton will effectively "decay" into a positron and an anti-neutrino. If this happens it is called "infra-red slavery" (We still are the champions of the non-vocabulary competitions - have to keep up appearances).

Because we are talking grains of sand inside a container the size of the Earth, it has been forecast that this will not happen for about :

100000000000000000000000000000000 years

(1 followed by 32 zeroes).

And I thought waiting for buses was bad

Spank Me

Here is a true story. Way back in the 60's, when atom smashing was just starting, it was thought that the basic building blocks of matter were not really that basic after all.

Protons and neutrons were bashed together so violently that they acted like they were made of smaller bits.

These bits were named "quarks", after the word from the book Finnegan's Wake. At first, two were enough to explain all of normal matter, and we called the "up" and "down" quarks. However, strange things started to happen soon after.

Literally.

Particles flew out which did not behave as they should have. Then to add insult to injury, us scientists added to the "up" ans "down" quarks another "flavor" of quark.

We called these strange particles "strange" particles.

This one was much heavier than the previous two, so it took much more energy to produce it.

The prediction was then made of a further "flavor" of quark, available at still higher energies.

Once again, our verbosity got the better of us and we named it "charm".

This quark first appeared in what we lovingly called a "charmonium" - a particle made up of one charm and it's antiparticle.

To scientists, this was not good enough - we wanted pure charm, ie charm on it's own. So the search for "bare charm" was begun.

As the energy of the accelerators increased, sure enough, bare charm was found.

That brought the quarks to four (up, down, strange, charmed).

It gets even funnier. The theorists told us that the had figured out that there were no more than a total of six.

So we got our thinking caps on again and came up with two more wonderful names - "bottom", and "top" , each one still heavier than the last. At first, we found the "bottom" quark, then eventually, the "top"

Imagine the remarks that were made when we tried searching for "bare bottom".

That just about sums it up really

That GUT feeling

For centuries, well, decades, at least, mankind had striven to find a theory of "everything". That is, one single math formula that describes all of physics.

That goal is still some way off, despite massive strides that have been made towards it.

The argument goes something like this:

A total of four different forces have been identified. Please note as opposed to the previous post, these are specific kinds of force, whereas the previous post dealt with the CONCEPT of a force.

These four "types" of force hold the Universe together. However, they are somewhat limited in various ways.

In detail, these are they:


The Oldest known, Gravity. It acts on everything and is always attractive.

The next to be studied was Electricity, or as it is now known, Electromagnetism. This acts only on stuff that is electrically charged. That is, stuff that is not neutral electrostatically. We do not know what charge "is" yet, even today, just that stuff with the same "charge" repel, and stuff with opposite "charge", attract. There are only two of them

The third force is called the "strong" force, is always attractive and acts only on stuff that is desperately close.

The fourth is the "weak" force (we ran out of names long ago) and only acts on radioactive stuff (it causes atomic nuclei to split up)

There are no others

Each of these "forces" has it's own set of equations that describe only it (electromagnetism has four of its own)

It has long been a dream of all science to unite all these equations into one.

It has not been done yet.

They all seem to have two things in common, though. They all have a specific "range" and all use "exchange particles" to be felt. That is except gravity. Gravity has infinite range, but no "exchange particle" has ever been detected.

There may be hope, though. In 1974, Steven Weinberg and Abdus Salaam (I forget the name of the third), managed to marry the "weak" force with electromagnetism, calling it the "electroweak" force. The prediction, if this were true, would be three new "exchange" particles called the W+, W- and the Z-0. It wasn't until 1983 that we had the particle accelerator powerful enough to produce them, as they were predicted to be very heavy (E = mc squared, after all). Sure enough, they turned up.

So we had three forces now, not four.

There have been reliable equations suggesting that the "electroweak" can be married to the "strong" force, although to prove this we would need an accelerator the size of the galaxy to detect these exchange particles (dubbed the "X" particles)

However, there was another prediction from this marriage - proton decay. Protons are to all intents and purposes, stable, although the other one, the neutron, decays in about 16 minutes.

If the Electroweak and the Strong forces, were really part of a bigger picture, the proton would have a half-life of about 100000000000000000000000000000000 years (1 followed by 32 zeroes).

Since the universe is only about 15000000000 years old, none would have gotten round to decaying yet, UNLESS we watched 100000000000000000000000000000000 protons for a year.
Us peeps have been doing this for maybe a decade now, and so far no results (it is very hard to detect just one amongst all those, even without red herrings coming from just about everything else.)

If we do detect proton decay, we will only have gravity to deal with.

That is the be-all and end-all. Gravity, almost like an unusually stubborn mule, blatantly refuses to conform.

Ok, so there may be a way out by conjecturing "m-theory", "brane-theory", and "string-theory", but to prove this requires travel in eleven dimensions. In other words, these are only words, not proof.

Warning! SUBJECTIVE STUFF!

Gravity differs because it is geometric as refined by Einstein. The other three are gauge FIELDS, and require exchange particles to be felt.

Geometry by definition does not require exchange particles and I am surprised that even Einstein tried to meld his own theory with the other established forces. Maybe it was peer pressure.

END OF SUBJECTIVE STUFF

Suffice it to say, we do not really have a Grand Unified Theory (GUT) yet, although we may have one for everything except Gravity.

The whole picture can be summed up in an energy diagram (see below), as we believe all the forces were one once, when there was so much energy there was no distinction. As the Universe expanded from the Big Bang, the amount of energy decreased (per cubic meter) and the forces separated in a process known as "symmetry breaking". Th.e diagram shows that gravity is conjectured to be there, but that is more like hope than speculation

We try to address this by putting lots of energy into our particle accelerators to maybe recreate conditions as they were during the big bang.



We still have a GUT feeling one is out there somewhere. Lord knows, we've tried!

The Low-Temperature Fairground

Well, There are not enough comments over here to keep this thing going, but I love my physics so much, I will do so. However, here's a point which piques the curiosity....

Superconductivity. Superfluidity.

What are they?

It happens at low temperatures. Low temperatures.

Very low temperatures.

Ok, without the details, here is what you see...

1. Substances conduct current for years without a power source.

2. Liquids appear emptier than empty space.

3. Liquids fall out of their own containers by themselves.

Helium is called a superfluid and has been well-studied. It seems to look like a combination of two different Heliums (maybe "Helia"??). Called Type 1 and Type 2. It exhibits superfluidity according to how near it is the Lambda point at 2.17 K. Only when it reaches 2.17 K does it become truly superfluid.

These are number 2 and 3 above. Technical term for No2 in "viscosity" - that is a word that means how hard it is to move a hand through the fluid. For instance, it is more difficult to move your hand through crude oil than through water, and more difficult to move your hand through water than any gas (gases and liquids are both called fluids in physics). As for the liquid Helium, is is easier to move anything through it than a gas, or even empty space. It feels like it is not there. It has zero viscosity.

No 3: A strange property of zero viscosity is that there is no resistance to the flow. The molecular movement inside the Helium is enough to drive it up the sides of any container ( from which it has no friction at all ), climb over the rim, and run down and drip from the lowest point.

As for metals, which is No 1 above, or more specifically, ceramics, the behave like there is nothing to stop the electricity flowing.

Ceramics are studied because their "lamba point" is much higher than 2.17 K. In fact, and this is not my field, but ceramics were close to having a lambda point at close to 79 K. This is significant because this is the boiling point of Nitrogen, and Nitrogen is much more common than Helium (Nitrogen is 78% of our atmosphere, Helium can only be gotten from rocks), and so is much, much cheaper.

However, for our coils, they have to copper, as here we have the conservation of energy again, as the advantage gained in the higher temperature superconductivity, is offset by the fact that ceramics are not good conductors.

Copper has lots of free electrons in it, Ceramics do not, and we can get a bigger non-resistive current if we are prepared to pay for the more expensive Helium.

Upshot is,

Copper: bigger current, lower temperature for switching superconductivity on, therefore more expensive Helium is needed.

The Ceramics: smaller current, but higher temperature for superconductivity switch on, therefore cheaper because maybe only Nitrogen needed.

The LHC needs copper to power the large magnets because the particles go so fast we need the magnets to be far more powerful because they have to turn the now heavier particles because of special relativity ( lol too many "because's )

Swings and roundabouts with a vengeance.

Just what is a Quark anyway?

Apart from being a character in Deep Space Nine, a "quark" is a very fundamental building block of nature. The best way to explain what they are is to tell how they came about.

It was the 1960's, and the people at SLINAC (Stanford Linear Accelerator) and CERN (Centre pour European Recherche Nuclaire) thought they had finally got the big picture of atoms, nuclei and stuff. But the machines doing this smashing suddenly produced some particles never before seen. They behaved differently from the others and were labelled "strange". They disappeared very quickly into energy according to E = mc**2. None were present in nature.

Where did they fit in? The whole kaboodle could be explained by a whole new way of thinking: that protons and neutrons themselves were made up of something even smaller. Indeed, scattering experiments (firing the particles at themselves) seemed to indicate, by the pattern alone, that there was something else inside. Electrons had nothing inside them. Scattering experiments with them told us they acted like true "point" particles.

But just what was inside the protons and neutrons? They settled on the name "quark" and the proton and neutron had three each. One had two "up" quarks and a "down" quark, and the other, two "down" and an "up". "Up" and "down" being arbitrary names having nothing to do with the normal meaning, they might as well have called them "Laurel and Hardy", or even worse,"Bill and Ted".

But what were the strange particles? They reasoned that these must have another "flavor" of quark inside (nothing to do with taste!), which they called "strange". They predicted other particles to turn up with other combinations of up, down and strange, and sure enough, as energies (accelerator energies) went up, these predicted particles turned up. Then they reasoned, "Why stop at three quarks?" - there could be more. They tentatively predicted a fourth, and they called it "charm" (!), and this would produce around 33% more new particles. The lowest energy of these was called the "Charmonium", and yes, it was found, along with all the debris. It was essentially a quark-antiquark pair, or "bare" charm.

How many more were there, and where would it stop? For reasons not appropriate to be given here, they figured out there were no more than 6 in total, and they called the last two "top" and "bottom".

These quarks were getting heavier and heavier and were very hard to produce, but the last one to be detected was bare bottom, in the mid-80's.

It has to be borne in mind that it was never the quarks they saw, just big particles with quarks inside. The question arose - why can't we get a quark on it's own. It would be pretty easy to detect, as each had either 1/3 or 2/3 of the charge on the electron. However, not one had been seen,

The reason they gave was astonishing. Up till then the forces of nature were gravity, electromagnetism, the weak force (only affects electrons and neutrinos), and the "strong" force, which keeps a nucleus together against the static electromagnetic repulsion of the protons.

They reasoned that inside the protons, the strong force was the real strong force, much stronger than had previously been thought, and it was this that was "holding" in the quarks, as if they were tied to it with elastic bands. ( see previous posts for more info). Try to pull a quark out, and the elastic gets more stretched, as it gathers energy from the "pulling", until SNAP it breaks in the middle, not with a loud noise, but a new quark-antiquark pair, matter from energy (E = mc**2). The quark goes back into the old particle, and the new antiquark makes another new particle with the quark just pulled out!

There was another problem with this scenario. It goes back to an old rule developed by Wolfgang Pauli - no two particles can have the same description and be at the same place.

But in the proton there were two "up" quarks!! They figured. that the strong force, like electricity, had the equivalent of "charge", but whereas electricity has two, plus or minus, the strong force had three, and they called these three "color" charges (nothing to do with rainbows). So, in a proton, an "up " must have a different color charge to the other "up".

Because of this "color field" they named the theory Quantum ChromoDynamics.

Believe it or not, that was an introduction. I have left much out.

There IS truth out there!

The Angry Bits

This blog has now come Full Circle (as M Palin would put it) as I am now at a similar position as I was when I started this thing. I now work at CERN again. My permanent post is at Incheon University, but I am the (silent) manager of a project at CERN called the SSA.

The SSA has nothing to do with what CERN is about however.

CERN has been operational since the 1960's, the World's biggest scientific collaboration. It is perhaps the largest telescope in the world. We use bigger and bigger telescopes to see into space, which by virtue of being far away, details are small. Similarly, CERN represents a telescope devoted to "seeing" the very small, by virtue of them actually being small. We call the largest one the Large Hadron Collider, the LHC.

It bashes bits together and has already been under scrutiny in this blog (Three jets are better than two). It makes Hadrons.

A "Hadron" ( pronounced " Hey! - dron!") is a particle bigger than a proton or neutron. It is important to remember that everything we see around us is made up of only protons, neutrons and electrons. "Hadrons" are created by smashing protons together to get "angry" bits - bits that don't belong in the real world. We called them "strange particles" at first, because we didn't know what they were.

Now we know that all the evidence fits like a jigsaw puzzle into thinking that all hadrons (protons, neutrons, plus angry bits) are made up of three new particles called "quarks" (from the book "Finnegan's Wake"). These quarks build up all the particles, except the electrons which seem to act like they have nothing inside at all.

All these particles are very small and behave unlike normal particles, ie billiard balls. It was first realised they were different by Neils Bohr. This was then made into a formula by Prince Louis De Broglie, and then finally made rigorous by Schrodinger et al. as Quantum Mechanics.

The basic concepts behind quantum mechanics are thus: 1. All particles also behave like waves of something ( they give answers that can only be explained by considering them as a stream of waves. "Waves of what?" I hear you say - the answer to that only comes when you understand the math behind statistics and wave mechanics - trust me) 2. You cannot know with infinite accuracy all things at the same time. 3. A new thing called 'spin" has to be called for to explain some of the things we have seen (It is NOT real "spin" as in going round and round, but just another number (we ran out of names to call these things early on)) 4. Some of the effects we have seen can be explained by a particle description AND a wave description , depending on the way we look at it. 5. These things only happen when the particles in question are very small.

So what does CERN do? Simple, we bash the bits together to get new ones, well, we used to. We have just about gotten sick of all the new bits we get out of our collisions, and now we refine the bashing to get the bits back in more useful ways. It's a bit like a car crash, we now know what bits to expect out of the car crash, but now, we bash them together at different "angles" to see which parts survive best at those angles.

The upshot of which is that we are continuing to refine the theory (Quantum ChromoDynamics or QCD) so as to predict next which bit of the engine will come out of our crash and which way it will go.

If it comes out the right way, we predict stuff about the wing mirrors, etc, if not, and we get more angry bits, we go back and try again with a different version of the theory to explain what happened before the prediction went wrong.

As for the SSA, it is just a tool to make the data collection easier, nothing fancy.

The final upshot is that there are no more angry bits any more.

Setting the Jets

I intimated in my "Angels and Demons" post that I would go further in explaining what a 3-jet event was.

I have been so preoccupied lately I have not had a chance until now.

A "3-Jet event" happens only at CERN and it occurs when particles of matter (protons, the basic building block of matter) collide head-on with anti-protons (their complete opposite).

Both are produced at CERN and when you put them together anyway, a lot of energy is released (according quite correctly to E=mc2). All mass is converted to energy in the form of electromagnetic radiation (light to you and me).

However, CERN make these particles come together at near light-speed, so there is a lot more energy available to do things with.

The most important is that the energy is so great, that it is easier to create new matter (via E=mc2) than to continue being just "radiation". In the same way it is easier for a rubber band to "snap" then to keep being stretched.

What happens? New particles are created, and they run away from the creation point at 180 degrees from each other. Why? The reason is to conserve momentum, as the initial momentum is zero, so must the final momentum be.

That is a 2-Jet event, sprays of particles run away from each other at diametrically opposed angles.

But SOMETIMES there are THREE.

Conservation of momentum aside, how in ATLAS could there be three?

Three-jet events occur because there is something else happening. Something which PROVES that quarks do exist, and harbour the true nature of the strong force.

Am I going to explain just exactly what it is that is happening in a 3-Jet event?

Not just yet....

You need to know a little more about basic electromagnetism first.....

...and THAT, I will leave to the next post on this so interesting a subject.

Hasta la Vista, Babee.

"Angels and Demons" - Reality Check!

Yes, you have guessed it, I am reading the second first book by Mr Boring Author Name Award 2005 - Dan Brown.

"Angels and Demons" is the precursor to "The Da Vinci Code" (See my post).

It is a story that starts where I have just given up a job - CERN (Centre European pour la Recherche Nucleaire), and central to the plot is an understanding of what antimatter is. Everything he says about CERN is correct, but he needs to brush up on his Physics a little!

Of course I know what poetic license is, but all the same, allow me to enlighten you a little as to the difference between Dan Brown and physics.

Anti-Matter? Physics. Recent production? No, CERN have been doing it for 20 years.

LHC? Yes, it exists, I have been there. Diameter 8 km? Yes.

Making a miniature Big Bang in the LHC? No. Making matter from nothing? No. Mr Brown conveniently forgets about all the energy needed to send the particles around the ring.

Matter-antimatter energy conversion 100% efficient? Oh yes!

Here's the rub - Bottles of antimatter? ABSOLUTELY NOT!

Many reasons:

1) Antiprotons need a true vacuum to be stable. Even intergalactic space is not even a true vacuum (see my space Sickness Pills post), and certainly a true vacuum on earth is impossible, and certainly if one is created, minute leaks will soon cause annihilation.

2) Stable magnetic bottle? Well, we are still working on that one, and it is not quite perfected yet.

3) The Bottle in the story has a quarter gram of antiprotons. Antiprotons have a negative charge. All of them. To overcome the negative electrostatic repulsion, one would have to have GI-normous magnetic fields involving magnets the size of rooms.

The REAL stuff that CERN does with antiprotons is exactly as Mr Brown explains - we throw protons round the LHC and using the same magnets, hurl antiprotons the other way. It works because they have the same mass.

At certain points in the ring we collide them, and collect the debris using huge detectors the size of office buildings.

What happens when a proton (travelling at 99% the speed of light) collides with an antiproton (travelling with the same speed in the opposite direction)? Annihilation, of course! But in this case, not only is the energy from the particles' mass available (939 MeV x 2 via e=mc2), but also the relativistic kinetic energy x 2.

Result; Two gamma rays, travelling in opposite directions (2 because both energy AND momentum need to be conserved). These gamma rays have so much energy that the reverse now happens.

Using E=mc2 many other particles are simply created (yes, created out of thin air, one particle, one antiparticle)

Why does this happen? It is exactly like a spark of electricity or lightning. In either, there is so much charge, that despite being an insulator, the air breaks down and carries a current.

Same with these two gamma rays, and they both become two "jets" of particles. These are called two-jet events, and were used to discover the intermediate vector boson, predicted in 1974, the carrier of the weak force, the Z-0. This was detected in the early eighties.

Sometimes, though, but not very often, we see a "3-jet event". That is, the two gamma rays become three jets instead of two. This is a purely gluon event........

For more, just watch this space.....