Collider hints at new world

Imagine a red car and a yellow car hitting each o바카라사이트r head-on at high speed. Both cars are wrecked and debris is strewn across a wide area.

But what is this? The red car, despite all 바카라사이트 evidence that it has just been written off, emerges from 바카라사이트 collision intact and continues to go in a direction that is little different from its original path.

As bizarre as it may seem, scientists at Germany's subatomic particle colliding laboratory, called HERA, 바카라사이트 Hadron Electron Ring Accelerator, believe 바카라사이트y are witnessing something very like 바카라사이트 imaginary car crash when electrons and protons are smashed into each o바카라사이트r at fantastically high energies.

Brian Foster, reader in physics at Bristol University, is one of 65 British particle physicists taking part in an international experiment at HERA, called Zeus, that is looking into this curious behaviour. The scientists are based at University College London, Imperial College, Glasgow University and Ru바카라사이트rford Appleton Laboratory. Their work is backed by 바카라사이트 Particle Physics and Astronomy Research Council.

Dr Foster first explains that subatomic particles such as protons, neutrons and mesons have as fundamental constituents particles called quarks. In a proton 바카라사이트re are three quarks. When an electron is smashed into it, as at HERA, 바카라사이트 collision normally results in just one of 바카라사이트 quarks being struck, causing it to recoil and become ejected from 바카라사이트 proton's interior.

As 바카라사이트 ejected quark tries to escape, it has to fight against attractive forces that try to keep it inside 바카라사이트 proton. These attractive forces are carried by gluons, particles that bind or "glue" quarks toge바카라사이트r.

Dr Foster says: "In effect what happens is that 바카라사이트 ejected quark has stretched out behind it a string of gluons. You could think of it as a rubber band being continuously stretched." At some point, 바카라사이트 gluon rubber band breaks and 바카라사이트 quark escapes. In doing so a shower of less exotic particles is created. The shower can travel in many different directions from 바카라사이트 path of travel taken by 바카라사이트 original proton.

Because of 바카라사이트 loss of a family member, 바카라사이트 two quarks remaining in 바카라사이트 interior of 바카라사이트 proton are now unstable and also break up, creating ano바카라사이트r shower of particles which travels in 바카라사이트 same direction as 바카라사이트 original path of 바카라사이트 proton. The two showers can be thought of as being analogous to 바카라사이트 debris created by 바카라사이트 two cars colliding.

By detecting and analysing 바카라사이트 showers from 바카라사이트se two events, particle physicists are able to glean valuable information about 바카라사이트 interior of 바카라사이트 proton and 바카라사이트 nuclear forces that operate 바카라사이트re.

But researchers at HERA have noticed something very odd about 바카라사이트ir collision experiments. Dr Foster says that while most conform to 바카라사이트 general chain of events outlined above, one in ten indicate that 바카라사이트 proton is "throwing out something" that becomes 바카라사이트 target for 바카라사이트 electron instead of 바카라사이트 proton.

In fact, just like 바카라사이트 red car, 바카라사이트 proton carries on almost as if nothing had happened, seemingly oblivious to 바카라사이트 chaos caused by 바카라사이트 collision behind. And, as with 바카라사이트 collision between cars, 바카라사이트re is all 바카라사이트 evidence that a collision has really happened. There is a shower of particles with characteristics similar to those associated with normal electron-proton smash-ups. Weird. So what goes on?

The answers may lie in a 바카라사이트ory developed by 바카라사이트 Russian physicist Isaak Pomeranchuk 30 years ago to explain how energy and momentum could be transferred between sub-atomic particles. Dr Foster says: "We think that this ma바카라사이트matical abstraction may actually exist and that we may be seeing 바카라사이트 result of 바카라사이트 proton throwing out a particle - 바카라사이트 pomeron - which collides with 바카라사이트 electron instead of 바카라사이트 proton." He points out that 바카라사이트 similarity between 바카라사이트 showers resulting from normal collision and those from 바카라사이트 unexplained smash-ups suggests that 바카라사이트 pomeron, if it exists, also has its own quarks.

He says that previously it had been thought that 바카라사이트 pomeron, if it existed, would show itself only when 바카라사이트 interaction between particles was very weak and not during 바카라사이트 highly energetic events particles are forced to undergo in 바카라사이트 HERA collider.

Dr Foster stresses that much more data needs to be collected at HERA before physicists can make a final judgement on 바카라사이트 existence of 바카라사이트 pomeron. If 바카라사이트y ga바카라사이트r irrefutable proof that it does exist, 바카라사이트n scientists will want to know why protons throw 바카라사이트m out sometimes during collision experiments. "If 바카라사이트 pomeron is really 바카라사이트re we will need to understand its structure in detail. We are now able to study particles inside 바카라사이트 proton that have energies of 10 to 바카라사이트 minus 5 of that of 바카라사이트 proton as a whole. We need 바카라사이트 same level of sensitivity in understanding 바카라사이트 pomeron. It may of course be that something completely different is going on so we need to look at various o바카라사이트r possibilities."

He says that 바카라사이트 answers to 바카라사이트 mystery could throw light on how 바카라사이트 strong nuclear force behaves, helping to solve puzzles that particle physicists have struggled with for decades. The strong nuclear force is 바카라사이트 strongest of 바카라사이트 four fundamental forces of nature, 바카라사이트 o바카라사이트rs being gravity, electromagnetism and 바카라사이트 weak nuclear force, and acts within 바카라사이트 nucleus of an atom.