A vast cavern is the stage for tests to find the 'God particle'

The Times ^

[andy224]

Atlas holds key to scientists' map of Universe By Mark Henderson A vast cavern is the stage for tests to find the 'God particle'

SCIENTISTS have taken a step closer to finding the “God particle” that is thought to shape the Universe. In a concrete cavern 130ft deep and bigger than the nave of Canterbury Cathedral, they will mimic the high-energy conditions that existed fractions of a second after the Big Bang to study a beam of energy a quarter of the thickness of a human hair.

The vast Atlas cavern, which was completed last week at Cern, the European nuclear physics laboratory on the Franco-Swiss border, will house parts of a giant atom-smasher that is expected to solve the most elusive riddle in physics.

When the £1.5 billion Large Hadron Collider (LHC) is switched on in 2007, it will determine once and for all whether the Higgs boson, a mysterious fundamental particle held to give matter its mass, really exists. If the machine finds the boson, proposed by Professor Peter Higgs of Edinburgh University in 1964, it will prove that the Standard Model for the nature of the Universe is correct. If not, the maxims of modern physics will be thrown into disarray.

The boson was nicknamed the “God particle” by the Nobel laureate Leon Lederman for its centrality to the cosmos. Although it will be so small that its presence can only be calculated, not seen, the search for it requires some of the largest and most advanced scientific instruments designed.

The LHC itself is a ring 17 miles (27km) in circumference, buried up to 100m (330ft) underground, through which streams of protons will be bent by the world’s most powerful magnets and smashed into each other at close to the speed of light.

The new cavern, which will house the Atlas detector for tracking the Higgs and other particles, is 40m (130ft) deep, 55m (180ft) long and 35m (115ft) wide.

However, the proton beam that runs through both devices measures just 10 microns in diameter: less than a quarter of the thickness of the average human hair. Roger Cashmore, a British physicist and Cern’s director of research, said: “It is an astonishing feat of engineering. The consultants were on the verge of saying it was impossible to build. But the Atlas cavern is finished, the biggest of its kind in the world, and these experiments are going to tell us whether we’re right about the Universe.”

The current best guide to the nature of the Universe is the Standard Model, an elegant theory that describes how most particles and forces interact. The Higgs boson is its missing keystone: without it, there is no good explanation for why matter has mass and therefore exists.

According to the theory, the Universe is permeated by a field of Higgs bosons, which consist of mass but very little else. As particles move through the field, they interact with it like a ball dropped into a tub of treacle, getting slower, stickier and heavier. Their ultimate mass depends on the strength of the interaction.

Though mathematics predicts its existence, the Higgs boson has never been detected. It is so heavy that the biggest atom-smashers, Cern’s Large Electron-Positron collider (LEP) and the Tevatron at Fermilab in Illinois, have been unable to generate the high energy collisions needed to reveal it, although they have found hints that it is probably there. This is where the LHC comes in. It is 70 times as powerful as the LEP and seven times stronger than the Tevatron, covering all the energy values at which the Higgs might exist. If it is there, it will find it.

What is more, if the “God particle” proves to be a false deity, the LHC will unlock the secret of what is out there instead. “If it doesn’t find the Higgs, it will find what substitutes for it,” Dr Cashmore said.

Jim Virdee, Professor of Physics at Imperial College, London, and a leading Cern researcher, said: “There has to be something else, beyond what we have found already, that explains mass. We believe it’s the Higgs, but Nature may be smarter than us. Either way, the results will tell us what is the right road.”

The atom-smasher will accelerate protons so close to the speed of light that they become 7,000 times heavier than normal. The beams are bent into a circle by superconducting magnets, cooled by liquid helium at -271.4C, almost a degree colder than outer space.

When the protons collide, they are destroyed in a huge burst of energy. This energy coalesces into very heavy particles, one of which scientists hope will be the Higgs.

As the boson is unstable, it will quickly decay, scattering a characteristic signature of smaller particles and energy. These will be picked up by the LHC’s eyes — the Atlas and a sister detector — which surround the collision points.

The detectors, which stand 22m (72ft) and 15m (49ft) tall respectively, are “giant microscopes” built like onions, with several layers of instruments that track particles and measure energy.

The experiments will generate enormous quantities of data, much of it unwanted. “Colliding two protons is like colliding two oranges,” Dr Lyn Evans, director of the LHC project, said. “You’ll occasionally get a collision between two pips, the interesting bits, but you’ll get a lot of pulp. We need to reject an enormous amount of data to pick out the important bits.” Professor Virdee said that the data generated in one second was the equivalent of what all the world’s telecommunications generated in one year.

Even if this wealth of information proves the existence of the Higgs boson, the LHC will continue to serve scientific knowledge for decades.

“Let’s say we have the Higgs,” Dr Cashmore said. “I’d feel warm and content for a few microseconds, then I’d be asking new questions. Why does it affect different particles in different ways? “It would be spectacularly good to find it — I’m not trying to knock it — but it will pose a whole new set of problems. If we are an inquisitive society, these are the things we ought to be doing."

[AndrewC]

I'm pretty sure they mean that the region AT THE TIME OF INFLATION must TODAY be at least the size of the observable Universe, which is exactly what 13 billion years of normal non-inflationary expansion does to to the Universe.

You didn't read the link. -- "at least" means something.

How much inflation do we need to solve the horizon and flatness problems? We will see that sensible models of inflation tend to place the inflationary epoch at a time when the temperature of the universe was typical of Grand Unification,

(75)

so that the horizon size, or size of a causal region, was about

(76)

In order for inflation to solve the horizon problem, this causal region must be blown up to at least the size of the observable universe today, ⁽⁸⁾

(77)

So that the scale factor must increase by about

(78)

or somewhere around a factor of e⁵⁵. Here the extra factor a(t_i) / a(t₀) accounts for the expansion between the end of inflation T_i ~ 10¹⁵ GeV and today, T₀ ~ 10^-4 eV. This is the minimum amount of inflation required to solve the horizon problem, and inflation can in fact go on for much longer.

It doesn't take but one more 10²⁴ inflation to make up for much of the 10²⁸ expansion. I take it that much longer means several periods longer.

My point has been clearly a problem with any matter being involved in the inflation.

[AndrewC]

Sorry about "you didn't read the link". I read your post and then clicked on the reply button. I took a fair amount of time in forming the reply and didn't see this intervening message, however my answer still applies, barring the "you didn't..." part.

[PatrickHenry]

Inflationary PLACEMARKER

[A. Pole]

Cheap at any price, even £1.5 billion, to get us a little closer to understanding the universe.

Certanly a cheap way to get rid of a planet!
See A black hole ate my planet

[jwalsh07]

So in that sense, you've asked what is technically an ill-formed question; for which there is no answer because the question assumes facts contrary to the theories you are expecting to provide the answer

Really? But if inflation had occurred one unit of time earlier, then t=0 would have happened at t={-1}.

But thats neither here nor there. You tell me I've asked a technically ill-formed question while you expound on a technically ill-formed theory that violated the first law of thermodynamics and every other law during inflation.

You have no idea what dark matter is, it has never been observed and can't be found in our galaxy. Yet it constitutes anywhere from 70 to 90% of the Universe depending on which Cosmologists you listen to.

The singularity came out of nowhere containing nothing except it had to contain at a minimum quanta and vacuum. So apparently something is south of the south pole, no?

[Dataman]

Right Wing Prof is opus'ed and gone?

(He was setting an example.)

ALS and conservababblerJen are still able to delete threads by wandering in, pooping in the punchbowl, and screaming in faces? This really bites bad!

I believe it was you who did the manly deed of pressing the abuse button against a woman and got the thread deleted.

[longshadow]

So the universe is still expanding, right?

Not only expanding, but expanding at an increasing rate!

only now it is either at or below the speed of light? Correct?

Depends upon what two points you chose to measure the expansion. If you choose a point within about 13 billion light years of Earth, we observe sub-luminal expansion, but since BB cosmology predicts the recessional rate (due to expansion) is proportional to distance, anything beyond about 13 billion light years would be moving away so fast that we can't see it... from here. IOW, everything beyond that distance is outside our light horizon, and is undetectable to us.

[Physicist]

IOW, everything beyond that distance is outside our light horizon, and is undetectable to us.

In principle that's true, but in practice the universe becomes opaque before we reach the edge of our Hubble volume. But you're right: the point should not be lost that, according to the observed flatness of the universe, it should be of infinite size in all directions, with all but our tiny, finite corner being geometrically unreachable to us.

[VadeRetro]

I believe it was you who did the manly deed of pressing the abuse button against a woman and got the thread deleted.

I value your opinion on the death of the last two crevo threads about as much as your opinion on transitional fossils. This thread has a real science article up front so I will spare it further discussion of what happened.

[Gargantua]

"Whereas if it were "faith" no amount of evidence would convince us we were wrong."

Amen.

[RightWhale]

You make my case.

Glad to be of service.

[Dataman]

Hey! Look what I happened across. Your home page?

:)

[longshadow]

It doesn't take but one more 10^24 inflation to make up for much of the 10^28 expansion. I take it that much longer means several periods longer.

My point has been clearly a problem with any matter being involved in the inflation.

It may be clear to you, but I'm not even sure what you feel is a problem here. Furthermore, I didn't notice anything in the section of the the website you quoted (which is far more authoratative than anything I can write on this subject) mentioning any "problem."

I suggest you take up your "problem" for Inflationary Cosmology with "physicist," who is vastly more qualified than I am to address whatever it is.

[longshadow]

But you're right: the point should not be lost that, according to the observed flatness of the universe, it should be of infinite size in all directions, with all but our tiny, finite corner being geometrically unreachable to us.

That's what I was getting at.

Correct me if I am wrong, but I believe the correct term to characterize those "unreachable" regions of the Universe is that they are "causally disconnected" from ours, and ours from them.

[AndrewC]

"causally disconnected" from ours, and ours from them.

A fancy term for supernatural.

[AndrewC]

I didn't notice anything in the section of the the website you quoted (which is far more authoratative than anything I can write on this subject) mentioning any "problem."

Relative velocities v > c are allowed in general relativity as long as the observers are sufficiently separated in space.

[longshadow]

"Relative velocities v > c are allowed in general relativity as long as the observers are sufficiently separated in space."

The complete quote is:

Relative velocities v > c are allowed in general relativity as long as the observers are sufficiently separated in space. (7) This mechanism provides a neat way to explain the apparent homogeneity of the universe on scales much larger than the horizon size: a tiny region of the universe, initially in some sort of equilibrium, is "blown up" by accelerated expansion to an enormous and causally disconnected scale.

[emphasis added]

Apparently, the author of the website you are quoting doesn't see this as a "problem," as much as he sees it as a solution.

But as I still have no idea what you see as "the problem," I can't really respond to it. Why not ask "Physicist" to help you out?

[AndrewC]

But as I still have no idea what you see as "the problem,"

I don't know how to explain it other than--->

When the distance between 2 things is increased(or decreased), something has moved. That is, when r₀ != r₁ something has moved.

[Hajman]

Godel's Incompleteness Theorem merely states that, in any "omega-complete" formal system -- in layman's terms, a system of sufficient expressive generality and abstraction to describe its own operations and permit self-reference -- there are demonstrably true statements for which no proof exists within that system. But this is strictly a mathematical phenomenon, based on the rigid mathematical definition of a proof.

You may be correct that Godel's Incompleteness Theorem is for the mathematically (and computer) inclined person, but it's still true that the universe can never be 100% explained.

-The Hajman-

[<1/1,000,000th%]

When the distance between 2 things is increased(or decreased), something has moved. That is, when r0 != r1 something has moved.

I think AndrewC is trying to understand the notion that 2 particles are now farther away, but neither of them moved. We used to just say the space moved, but I'm not sure that helps.

Inflation is one of those things that seems like happened, because it's consistent with known observations, but to me it's a lot like trying to understand the 2nd law of thermo. It requires several attempts with the alcoholic beverage of your choice.