Archive

Posts Tagged ‘CERN’

Fermilab Double-Checking CERN’s (and their own) Math

September 27, 2011 1 comment
Detector used in the MINOS experiment at Fermilab.

Of course the big news of the past week is the OPERA experiment’s measurement of neutrino’s travelling faster than light.

The paper is up on arXiv. I’ve gone through it and nothing jumps out as to what they could have possibly done wrong. Chad Orzel on his blog Uncertain Principles has written a really nice summary of the paper and what the group actually did.

(Aside: I just read How to Teach Physics To Your Dog by Orzel, and I would definitely recommend it to a reader with a budding interest in quantum mechanics.)

Now it looks like the US based Fermilab is going to go over some old data to see if they can support (or contradict) the results of the OPERA experiment.

It was back in 2007 that Fermilab announced the results of their MINOS (Main Injector Neutrino Oscillation Search) experiment. They also found neutrinos travelling faster than the speed of light, however they had a much larger margin of error than the OPERA experiment, so they did not receive much attention.

Now, they are going to go back over their old data, as well as add some new data, to see what they find.

“The MINOS experiment has plans to update their original 2007 measurement with a number of improvements, including 10x more data,” wrote MINOS spokesperson Jenny Thomas, a professor of particle physics at University College London in an email to TPM’s Idea Lab.

“We should have a result in 4-6 months as the data is already taken. We just have to measure some of our delays more carefully,” she added. [TPM]

So in 6 months (I know, science is slow!) we will hopefully add another chapter to this fascinating story.

______________________________________________________________________

REMINDER: This blog is moving! The new location is http://www.aquantumofknowledge.com/ 

The new RSS Feed is: http://feeds.feedburner.com/AQuantumOfKnowledge

Remember to update your subscriptions! This site will no longer be supported after September 30, 2011. 

Thanks! 

Ryan

Faster Than Light Particles! So, Warp Speed Ahead, Right???

September 22, 2011 3 comments

The OPERA detector at Gran Sasso National Laboratory in Italy

I’ll have more to say about this story once I see the work on arXiv, but I feel I should comment now because this story is exploding.

The interwebs and blogospheres are abuzz with the news that researchers at CERN have measured the velocity of neutrinos which seem to be travelling faster than light.

Neutrinos are nearly massless  subatomic particles which have been known to travel near the speed of light. But, like all other things in the universe, they are not supposed to be able to travel faster than light.

Basically the experiment involves the creation of neutrinos at CERN in Geneva, Switzerland, and the neutrinos travelling 730 km to a laboratory 1,400 meters underground in Italy. There, an experiment called OPERA (Oscillation Project with Emulsion-tRacking Apparatus) detects those neutrinos and measures how quickly it took them to make the trip.

The neutrinos arrived 60 nanoseconds sooner than they should have. This means they were travelling at a speed of about 299 800 km/s, which is slightly higher than the speed of light, which is about 299 792 km/s.

This discovery will rock the very foundation upon which modern physics is built. Seriously, this is like the discovery that the world is round or wave-particle duality; it’s a complete game-changer.

If it’s true.

Like a lot of folks out there, I am quite skeptical of this discovery. Think of it this way: which of these two scenarios is more likely,

  1. Particles can travel faster than light, completely re-writing modern physics and decades of previous research. Or,
  2. These guys made an innocent mistake.

Now, it is certainly possible that this discovery will turn out to be genuine. However, it is much more likely that there was some kind of error or misinterpretation which has led to this result.

I would like to point out that the researchers have revealed their work in the proper way. They are excited, but very skeptical themselves and are asking the academic community to review their work and try to find a flaw. Antonio Ereditato, a physicist at the University of Bern in Switzerland and OPERA’s spokesman said in an interview

Whenever you are in these conditions, then you have to go to the community

THIS is science in action, folks! A group of physicists think they have discovered something awesome. But they haven’t started trumpeting their results like they have been absolutely confirmed, no emails were leaked suggesting the discovery, and they didn’t go to some rogue publication to get their work in print prior to peer-review.

Beautiful, isn’t it?

I am very hopeful this turns out to be a genuine discovery. I can’t wait to read the papers and hear the response from the scientific community.

______________________________________________________________________

REMINDER: This blog is moving! The new location is http://www.aquantumofknowledge.com/ 

Remember to update your subscriptions! This site will no longer be supported after September 30, 2011. 

Thanks! 

Ryan

CERN Traps Antimatter…wait, I already did this…

June 7, 2011 Leave a comment

I guess it’s more official this time though.

Although the trapping of antihydrogen for more than 15 minutes was in arXiv about a month ago, just now it has hit big news and been published in Nature.

Since I’ve been pretty busy lately and haven’t been able to post much, here is the link to my post from May 4 detailing the research and how it was done.

Incidentally, the post was chosen as an ‘Editor’s Selection’ by ResearchBlogging.org. 

Enjoy!

CERN Traps Anti-Matter For 1000 Seconds

May 4, 2011 8 comments

ResearchBlogging.org

Antimatter is cool.

It lets us perform PET scans and powers the starship Enterprise. But it is extremely difficult to study.

That is because when anti-matter comes into contact with normal matter, they annihilate one another, emitting pure energy (photons). This is unfortunate for scientists because they would love to study anti-matter, but developing a trap for it is understandably tricky. The anti-matter particles can easily interact with background gases or the walls of the container.

But last year, researchers at CERN published a paper in Nature (which I also blogged about) describing how they managed to trap 38 atoms of anti-hydrogen (an antiproton orbited by a positron) for 172 ms.

They have not stopped working on improving their trap, however, and have now performed a study detailing how they were able to trap anti-hydrogen for 1000 seconds, an increase of nearly 4 orders of magnitude from their previous paper.

This is what they did:

First, CERN’s Antiproton Decelerator creates the antiprotons which will be used to create atoms of antihydrogen. The Anitproton Decelerator provides antiprotons in groups roughly 3 x 107 in number. Only anti-protons which have an energy less than a certain amount (< 3 keV) are trapped. Typically the number of antiprotons less than this energy threshold is ~6 x 104. These antiprotons are then cooled and compressed.

After this initial step, the antiprotons are then mixed with a cloud of positrons in an effort to get these two components to combine into atoms of antihydrogen. After mixing for about 1 second, the researchers end up with about 6 x 103 atoms of antihydrogen.

All this takes place inside a magnetic trap. The trap is cylindrical in shape and has a length of 270 mm and a diameter of 44.5 mm.

A schematic diagram of the anti-hydrogen trap (a). The other graphs in this figure show the strength of the magnetic field at different points in the trap.

In order to actually “trap” the anti-hydrogen atoms, a magnetic field is generated inside this cylinder. The field is shaped such that the magnetic field is weakest in the middle of the trap (~ 1 T), and stronger along the edges of the trap (~ 2 – 3 T). In this way, a type of “well” is created which keeps the antihydrogen atoms in the middle of the apparatus, which prevents them from interacting with the walls of the trap and annihilating themselves.

After holding the antihydrogen atoms for a certain period of time, the researchers would shut down the magnets and wait for the atoms to annihilate themselves by hitting the walls of the trap. A special detector counts these annihilation events and allows them to detect the number of anithydrogen atoms remaining after the experiment.

Why don’t all the antihydrogen atoms remain? Most of them are lost through interactions with gases inside the trap, such as helium and molecular hydrogen.

They varied the experiment time from 0.4 seconds to 2000 seconds, and did several attempts for all time lengths. As you might expect, they detected more annihilation events per attempt for the short time lengths (e.g. 1.13 ± 0.13 events/attempt for 0.4 second time length) than the longer time lengths (0.77 ± 0.29 events/attempt for 1000 second time length).

Ah but now you are thinking, “but they did some experiments at 2000 seconds, why aren’t we hearing about that?”

The reason is that they only did  3 experiments at the 2000 second time scale, and while they did detect a few events, the results were not strong enough to say for sure that they were able to trap antihydrogen at that time scale.

The paper also discusses some of their computer simulations and how they compare to the actual experiment results, but I will leave that to the interested reader. 

So what are the implications of this work?

Being able to trap anti-matter for this period of time will allow for much easier ability to perform spectroscopy, since the density of atoms and intensity of radiation needed are dramatically reduced in the anti-matter can be held for a long period of time.

In addition, trapping anti-hydrogen for this long time scale will allow researchers to cool the anti-matter to very low levels, allowing them to probe the effect of gravity on anti-matter.

This post was chosen as an Editor's Selection for ResearchBlogging.org

ALPHA Collaboration, G. B. Andresen, M. D. Ashkezari, M. Baquero-Ruiz, W. Bertsche, E. Butler, C. L. Cesar, A. Deller, S. Eriksson, J. Fajans, T. Friesen, M. C. Fujiwara, D. R. Gill, A. Gutierrez, J. S. Hangst, W. N. Hardy, R. S. Hayano, M. E. Hayden, A. J. Humphries, R. Hydomako, S. Jonsell, S. Kemp, L. Kurchaninov, N. Madsen, S. Menary, P. Nolan, K. Olchanski, A. Olin, P. Pusa, C. Ø. Rasmussen, F. Robicheaux, E. Sarid, D. M. Silveira, C. So, J. W. Storey, R. I. Thompson, D. P. van der Werf, J. S. Wurtele, & Y. Yamazaki (2011). Confinement of antihydrogen for 1000 seconds arXiv arXiv: 1104.4982v1

Dan Brown Novel Coming True? Antimatter Captured at CERN

November 17, 2010 1 comment

In Dan Brown’s novel ‘Angels and Demons’, a supposed terrorist group steals a sample of anti-matter from CERN in Geneva. They rig it up like a bomb in an attempt to destroy the Vatican.

Anti-matter is the bizzarro-counterpart to regular matter. For example, regular matter is made up of protons, neutrons and electrons. A positron, which is the anti-matter counterpart to the electron, has the exact same mass as an electron but has an opposite electric charge (positive instead of negative, hence ‘positron’).

When anti-matter comes into contact with regular matter, they annihilate each other, and get converted entirely to energy. This is what makes anti-matter so difficult to handle, because most of our universe is made of regular matter, so anti-matter never hangs around for too long before it gets converted to energy. It is also why Dan Brown uses it in his novel, as an anti-matter bomb can be much more powerful than a nuclear weapon.

For example, half a gram of anti-matter could release as much energy as the atomic bomb dropped on Nagasaki in 1945.

Mushroom Cloud Over Nagasaki, August 9 1945. From Wikipedia.

This isn’t very realistic, however, since anti-matter is so difficult to trap.

But now science fiction has once again turned into science, and researchers at CERN today published a paper in Nature, stating that they had successfully trapped 38 anti-hydrogen atoms (a positron and an anti-proton) in a magnetic field at one time for 170 milliseconds.

This is an important experiment because scientists have always wished they could study anti-matter more closely, but it’s extremely difficult to get under the microscope (so to speak). Studying anti-matter will give us insight into the origins of the universe. It is believed that matter and anti-matter should have been created in equal proportions at the big bang, so one of the greatest mysteries in science is what happened to all the anti-matter?

 The scientists at CERN hope that they will be able to trap larger amounts of anti-matter in the future for longer periods of time in order to facilitate some real studies of the stuff.

So should we be worried about an anti-matter bomb? Well remember 0.5 grams of anti-matter roughly makes a Nagasaki. These guys trapped 38 atoms which is about 0.000000000000000000000000063 grams.

So no, you don’t have to worry :)

One Step Closer to Finding the God Particle

July 28, 2010 1 comment

The God Particle, or the Higgs Boson as its known in the Physics world, is coming closer and closer to being found. (I recently wrote an article  about the Higgs, you can check it out here for a bit of background info)

Experimenters at Fermilab, which is a particle accelerator laboratory in the United States, are competing with Europeans at the new-fangled Large Hadron Collider (LHC) in Geneva, Switzerland.

They are competing for the ultimate prize: finding the Higgs Boson, and experimenters at Fermilab just narrowed the search a bit.

I see this competition like a nerdy version of Rocky IV. Fermilab is Rocky, the hard-nosed American underdog (Fermilab is much less powerful than the LHC) and the LHC is the engineered Russian super-athlete.

Fermilab vs. LHC

One of the biggest problems with finding the Higgs is that no one knows exactly what its mass is (i.e. how heavy it is). But we do know that the mass should be between 114 and 185 GeV/c2

Oh, and  GeV/c2 is a unit of mass that particle physicists use. I’m not gonna go into a whole lot of detail, but for comparisons sake the proton is roughly 1 GeV/c2

So the Higgs boson is supposed be roughly between 114 and 185 times larger than the proton.

But Fermilab just released some results which showed that the Higgs is NOT between the masses of 158 and 175 GeV/c2

So this narrows the search parameters a little bit, and hopefully it results in finding the Higgs a bit sooner.

Of course, NOT finding the Higgs boson would just as huge a result. It would mean the Universe is a whole lot weirder than we already thought, and there are those who think we won’t find it.

So exciting times in physics world. But of course its ALWAYS exciting in the physics world! You can try and keep up with all the excitement by following me on Twitter

The (Simple) Physics of the ‘God Particle’

July 21, 2010 1 comment

The ‘God Particle’.

Pretty catchy name. Its been in the news quite a bit lately. But what is it exactly? And why would they call it the ‘God Particle’? Especially since science and religion get along about as well as Frank and Estelle Costanza!

Well in this blog post, I’m going to give you a basic and (hopefully!) entertaining explanation of what the God Particle is, and why we should care. So let’s start at the beginning.

The ‘God Particle’ is also (and more accurately) known as the Higgs Boson. Described in a single sentence, it is believed to be the particle that gives mass to all other particles in the Universe.

Ok, that SOUNDS important, but its still a bit hard to understand, so here’s a bit more thorough explanation.

Everything in the universe is made up of particles. And there are several different kinds of particles.

All the matter in the universe is made up of atoms. Atoms are made of a nucleus, which is found at the center of the atom and has neutrons and protons in it. Surrounding the nucleus are electrons, which are much smaller and fly around the nucleus in a circle, or an ‘orbit’.

Groups of atoms can get together and form molecules, and big groups can get together to form rocks, trees, and Maria Sharapova.

So thats 3 particles we have already described (protons, neutrons, and electrons). These 3 particles have mass; this essentially means that they weigh something.

But there are other types of particles out there too. For example, there is the photon.

Photons are are basically light. They are tiny packages of energy that make up a beam of light. They also make up radio waves, x-rays, and gamma rays (the stuff that gave the Fantastic Four their powers).

But photons are different from, say, protons, because they don’t have any mass. They carry light energy from the sun, for example, to the Earth. Or they can carry radio messages from the radio station to your house. So photons are like messengers; as such, they are sometimes called “messenger particles”.

A “messenger particle” is also called a boson. Bosons are really cool because they actually DO something. What do I mean by that?

Well, if you remember high school physics or chemistry class, you know there are 4 forces in nature. Gravity is one of them, and it is the most familiar too us. Its what keeps us firmly planted to the ground. Electromagnetism is what makes electricity, light beams, radio waves, and magnets work.

You Can Visualize a Magnetic Field with Iron filings and a Bar Magnet

The other two forces are a little less familar. They are called the Strong nuclear force, and the Weak nuclear force. These two are basically what holds the nucleus of the atom together, and make it behave the way it does.

So what does this have to do with anything? Well remember bosons are messenger particles. The photon carries the electromagnetic force “message”. The other forces in nature have bosons as well that carry their “messages”. Gravity has the “graviton” (which hasn’t been observed yet but we think its out there). The strong nuclear force has the “Gluon” (because it ‘glues’ the nucleus together). And the weak nuclear force has the “W” boson (it doesn”t get a cool name because its not cool).

Ok, now we get to the Higgs boson. So, since it is a boson, it must be the “messenger” of something right? So what is it the messenger of?

Well, remember I said that protons, neutrons and electrons have mass? But the photon does not have any mass. Why is that? What is it that makes one particle have mass, and the other not have mass? Even a couple of the bosons have mass! Thats just freakin’ weird.

So particle physicists (one of the named Peter Higgs, oddly enough) came up with a theory. They think there is some kind of a field in the universe called the “Higgs Field”. Its kind of like a gravity field, or a magnetic field. Just like a magnetic field will interact with some iron to pull it in one direction, the Higgs Field will also interact with particles. But instead of pulling at them, the Higgs Field gives these particles mass! It makes them heavy!

The theory also says there should be something called the Higgs boson: an actual particle that carries the Higgs field “message”. And thats what we are trying to find. The Higgs boson is the messenger particle of the Higgs Field, which is (theoretically) what gives particles their mass. If we do find it, then we know our theories about how the universe is made are on the right track. It would be HUGE breakthrough for physics!

One problem: the Higgs boson is supposed to be heavy! Well, for a particle its pretty heavy.

In fact, the only way to actually “make” one is by slamming together stuff like protons at close to the speed of light in what we call a “particle collider”. And we need to slam them together at a really BIG energy, so we need a BIG collider. Thats why we have the Large Hadron Collider.

The Large Hadron Collider in Geneva, Switzerland

Ok, so thats the explanation of what the Higgs boson is and why we should care. So why is it called the ‘God Particle’.

Well, a guy named Leon Lederman wrote a book called “The God Particle: If the Universe Is the Answer, What Is the Question?which was actually about the Higgs boson. Calling it the “God Particle” was a kind of grandiose name because it suggested we knew what it was that gave particles mass, what made they heavy or “real”. Very “god-like” I suppose”.

The term “God Particle” also showed up in Dan Brown’s novel “Angels and Demons”. In the book some claimed that the discovery of the particle would prove the existence of God.

Finding the Higgs would be great, but would hardly prove the existence of God. The use of these terms is largely to increase media interest.

Phew, well there you have it. If you want to hear more about Physics news as it happens you can follow me on Twitter! Or you can follow the Large Hadron Collider on Twitter!