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Large Hadron Collider results excite scientists - Comments

weavehole's Avatar Comment 1 by weavehole

So an inverse femtobarn is the amount of collisions detected in an area the size of a neutrinos diameter (squared)?

‎1 yoctometre squared?

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Sat, 23 Jul 2011 06:07:27 UTC | #852910

cheesedoff17's Avatar Comment 2 by cheesedoff17

2.8 sigma =still an enigma.

Sat, 23 Jul 2011 06:36:44 UTC | #852915

Anonymous's Avatar Comment 3 by Anonymous

Comment Removed by Moderator

Sat, 23 Jul 2011 07:01:12 UTC | #852917

Stafford Gordon's Avatar Comment 4 by Stafford Gordon

The plot thins!

Sat, 23 Jul 2011 07:56:48 UTC | #852927

weavehole's Avatar Comment 5 by weavehole

Wait a minute. I got that wrong by several magnitudes. A yoctometre squared is a barn. A femtobarn is waaaaaay smaller.

These are the links I tried to post: Barn wiki Scale of the universe

Sat, 23 Jul 2011 08:12:51 UTC | #852932

Anonymous's Avatar Comment 6 by Anonymous

Comment Removed by Moderator

Sat, 23 Jul 2011 08:23:09 UTC | #852935

Jos Gibbons's Avatar Comment 7 by Jos Gibbons

In what follows, I apologise for all the "x to the y" comments, but as far as I know we still don't have a workable way to do exponents in these comments. Someone feel free to teach me if we do though.

Comment #852910 by weavehole

The rate N of events of a particular type you'd expect to see when you fire a beam of particles at a target is proportional to its luminosity L, defined as the rate of particles propagating past a fixed point per unit area. (Or you can time-integrate everything to be comparing particle number and particles past a point over the period per unit area.) Therefore, the proportionality constant must be an area. We call it a cross-section. One unit in which to measure it is a barn, which is 10 to the minus 28 square metres (or, if you prefer, 100 square femtometeres ,since femto- means 10 to the minus 15). Since yocto is 10 to the minus 24, a femtobarn is 10 to the 5 square yoctometres.

In particle physics we clean up formulae by setting c (the speed of light in a vacuum) and h-bar (Dirac's constant) to each be 1, and if necessary we can put powers of them back in later by considering units. For example, energy has the same units as h-bar*c/length, so we just say its units are 1/length. In this way, we can give everything a length dimensions, e.g. energy, momentum and mass are each 1/length, coupling constants are something else and so on. Of course, another way to look at it is length has units of 1/energy etc. This is why you often see things quoted in GeV to some power (possibly negative). But in some other contexts we do things by length powers, so an inverse femtobarn is of length dimension -2 or energy dimension + 2.

Here's Wikipedia on an inverse femtobarn:

The "inverse femtobarn" (fb−1) is a measurement of particle collision events per femtobarn. Over a period of time, two streams of particles with a cross-sectional area, measured in femtobarns, are directed to collide. The total number of collisions is directly proportional to the luminosity of the collisions measured over this time. Therefore, the collision count can be calculated by multiplying the integrated luminosity by the sum of the cross-section for those collision processes. This count is then expressed as inverse femtobarns for the time period (e.g., 100 fb−1 in nine months). Inverse femtobarns are often quoted as an indication of particle collider effectiveness.

In classical physics, if you strike a target which is guaranteed to interact when you strike it, and it is a sphere of radius R, the cross section of the interaction is simple pi R squared. If the interaction has probability p the cross section picks up a p factor, so you can turn cross sections into probabilities if only you know the right R. In particle physics, R is proportional to the de Broglie wavelength lambda of the particle, hence inversely proportional to its momentum. The probabilities depend on what are called coupling constants.

Neutrinos are famous for almost never interacting with matter. The interaction has a tiny cross section. Pontecorvo argued the cross section for a neutrino of energy E (for typical neutrino sources this may be, say, 1 GeV) should be approximately lambda squared * (lambda/c)/t, t the timescale of the weak interaction. This is just lambda cubed/ct, ct the range of the weak interaction. I think the cross section one obtains is a bit smaller than a femtobarn.

Sat, 23 Jul 2011 08:40:22 UTC | #852939

Roland_F's Avatar Comment 8 by Roland_F

So scientist are still hunting to find “The God particle” (Peter Higgs Boson) to proof that God exists.

And if found conclusively (Sigma > 5) it proofs that god is not Yahweh, Allah, Brahma …. but god’s name is Peter Higgs , and we all have to worship him as our true deity :-)

Sat, 23 Jul 2011 09:32:59 UTC | #852945

weavehole's Avatar Comment 9 by weavehole

Thanks Jos,

I'm going to look up 'lambda' when I recover from the Oktoberfest i'm just about to go to. But I think I get the gist of what you're explaining. :)

Sat, 23 Jul 2011 09:56:57 UTC | #852950

DavidMcC's Avatar Comment 10 by DavidMcC

"He told BBC News the collider had now ruled out more of the "mass range" where the Higgs might be."

If that is still all that has been achieved, then the headline is yet another piece of hype. :(

Sat, 23 Jul 2011 11:31:33 UTC | #852972

PERSON's Avatar Comment 11 by PERSON

"However, the experiments can now - unfortunately - exclude quite a large part of this allowed mass region."

Hold on, isn't it a good result if they don't find it? I mean, at least they get to throw out a theory that's demonstrably wrong. I suppose it's dispiriting if there's nothing to replace it, but as I understand it there're a lot of alternatives being developed.

Sat, 23 Jul 2011 11:45:45 UTC | #852976

Schrodinger's Cat's Avatar Comment 12 by Schrodinger's Cat

I calculate a 5 sigma probability that the cumulative editorial time spent checking LHC articles for a certain spelling mistake will soon exceed the cost of the LHC itself.

Personally I hope they don't find the Higgs Boson......as that will leave the door open for lots of other exciting physics.

Sat, 23 Jul 2011 11:49:36 UTC | #852978

Saganic Rites's Avatar Comment 13 by Saganic Rites

And if they do find the Higgs boson, I predict that all the stars will briefly blink out, and when they blink back on they will have rearranged to form "LEVEL 1 COMPLETED: STARTING LEVEL 2".

Sat, 23 Jul 2011 12:50:16 UTC | #853000

Marc Country's Avatar Comment 14 by Marc Country

"... Einstein's equivalence idea (E=MC2)".

Shouldn't that 2 be in superscript? I don't want anybody to screw up their calculations...

Sat, 23 Jul 2011 12:53:13 UTC | #853002

mmurray's Avatar Comment 15 by mmurray

Comment 14 by Marc Country :

"... Einstein's equivalence idea (E=MC2)".

Shouldn't that 2 be in superscript? I don't want anybody to screw up their calculations...

There are no superscripts on this website and the usual short hand of a hat or caret doesn't show up. You can use a html code for the caret character and get E=MC^2. But html code for a superscript doesn't work.

Michael

Sat, 23 Jul 2011 13:00:59 UTC | #853005

mmurray's Avatar Comment 16 by mmurray

Comment 13 by Saganic Rites :

And if they do find the Higgs boson, I predict that all the stars will briefly blink out, and when they blink back on they will have rearranged to form "LEVEL 1 COMPLETED: STARTING LEVEL 2".

LOL. Did you ever read The Nine Billion Names of God ?

Michael

Sat, 23 Jul 2011 13:08:18 UTC | #853012

huzonfurst's Avatar Comment 17 by huzonfurst

How about using two slashes to indicate superscripts: E=mc/\2 ? Kind of klutzy but less so than writing "to the power of" all the time.

This is the only comment system that doesn't display several non-alphabetic but otherwise commonly-used characters properly, and no one has ever explained why. With all the other choices out there, what is the rationale for using this one??

Sat, 23 Jul 2011 13:15:38 UTC | #853016

mmurray's Avatar Comment 18 by mmurray

Comment 17 by huzonfurst :

How about using two slashes to indicate superscripts: E=mc/\2 ? Kind of klutzy but less so than writing "to the power of" all the time.

Ah nice. You can use the HTML code "& # 9 4 ;" with the spaces removed and the double quotes removed. This becomes ^ when it displays.

You can get all the weird characters this way.

This is the only comment system that doesn't display several non-alphabetic but otherwise commonly-used characters properly, and no one has ever explained why. With all the other choices out there, what is the rationale for using this one??

I don't know but there was a spate of wacky colours and emoticons for awhile. It's possible administration got sick of people doing that so they use a system that strips out most of the html that the user puts in.

Michael

Sat, 23 Jul 2011 13:22:01 UTC | #853019

hairybreeks's Avatar Comment 19 by hairybreeks

ALT+0178 produces e=mc²

Sat, 23 Jul 2011 13:26:34 UTC | #853022

mmurray's Avatar Comment 20 by mmurray

Comment 7 by Jos Gibbons :

In what follows, I apologise for all the "x to the y" comments, but as far as I know we still don't have a workable way to do exponents in these comments. Someone feel free to teach me if we do though.

See my post above this one. Not quite what you want but closer.

Michael

Sat, 23 Jul 2011 13:27:25 UTC | #853023

mmurray's Avatar Comment 21 by mmurray

Comment 19 by hairybreeks :

ALT+0178 produces e=mc²

How do you do that ??

Ah I see: e=mc²

So you remove the spaces from "e = m c & # 1 7 8"

It appears you can do cubes as well.

Michael

Sat, 23 Jul 2011 13:28:11 UTC | #853024

Saganic Rites's Avatar Comment 22 by Saganic Rites

Comment 16 by mmurray

LOL. Did you ever read The Nine Billion Names of God ?

Thanks Michael, I haven't but I'm going look for a copy now; it sounds interesting.

Bryan.

Sat, 23 Jul 2011 13:34:24 UTC | #853027

mmurray's Avatar Comment 23 by mmurray

Comment 22 by Saganic Rites :

Comment 16 by mmurray

LOL. Did you ever read The Nine Billion Names of God ? Thanks Michael, I haven't but I'm going look for a copy now; it sounds interesting.

It's just a short story but an amusing sting at the end.

Michael

Sat, 23 Jul 2011 13:37:55 UTC | #853030

yvrous's Avatar Comment 24 by yvrous

Wy not E=mcc ?

Sat, 23 Jul 2011 14:20:36 UTC | #853058

weavehole's Avatar Comment 25 by weavehole

Comment 24 by yvrous

Wy not E=mcc ?

I don't like cricket?

Sat, 23 Jul 2011 17:57:23 UTC | #853173

BroughtyBoy's Avatar Comment 26 by BroughtyBoy

I have read this article three times. So far, I have surmised only that particles and scientists are getting in an excited state. That in itself is an education.

Sat, 23 Jul 2011 18:08:06 UTC | #853179

Universeman's Avatar Comment 27 by Universeman

Comment 13 by Saganic Rites And if they do find the Higgs boson, I predict that all the stars will briefly blink out, and when they blink back on they will have rearranged to form "LEVEL 1 COMPLETED: STARTING LEVEL 2".

lol, love it

Without the Higgs, physicists cannot explain why particles have mass. But despite the best efforts of scientists working on both sides of the Atlantic to detect it experimentally, the boson remains a theoretical sub-atomic particle.

It seems to me not being able to explain where mass comes from is Like trying to explain planetary motion without knowing what gravity is or trying to explain why the sun is so damn hot with out an understanding of basic atomic structure. If you’ll forgive my ignorance of subatomic particle physics, but not knowing why particles have mass means that we are ignorant of one of the most fundamental aspects of how the universe functions as a whole, doest it not?

We can't be said to understand the constituents of matter if we don't have a satisfactory answer to this question.

These questions, the mechanisms by which particles get their masses, and the relationship among different forces of nature, are major ones and so basic to having an understanding of the constituents of matter and the forces among them, that it is hard to see how we can make significant progress in our understanding of the stuff of which the earth is made without answering them.

I can’t make heads or tails of the following quote. Also I am curious what impact the discovery of the God Particle will have on the theology of religions, perhaps someone would care to elaborate on this?

There is, however, one very clever and very elegant solution to this problem, a solution first proposed by Peter Higgs. He proposed that the whole of space is permeated by a field, similar in some ways to the electromagnetic field. As particles move through space they travel through this field, and if they interact with it they acquire what appears to be mass. This is similar to the action of viscous forces felt by particles moving through any thick liquid. the larger the interaction of the particles with the field, the more mass they appear to have. Thus the existence of this field is essential in Higg's hypothesis for the production of the mass of particles.

The Need to Understand Mass How Particles Acquire Mass Higgs Boson: One page explanation

Sun, 24 Jul 2011 01:43:08 UTC | #853335

rod-the-farmer's Avatar Comment 28 by rod-the-farmer

All that firepower and they can't seem to hit the broad side of a femtobarn.....

Sun, 24 Jul 2011 09:09:33 UTC | #853419

QuestioningKat's Avatar Comment 29 by QuestioningKat

Universman asked -I can’t make heads or tails of the following quote. Also I am curious what impact the discovery of the God Particle will have on the theology of religions, perhaps someone would care to elaborate on this?

None, They'll just deny or adapt with a new explanation.

Sun, 24 Jul 2011 13:15:48 UTC | #853469

mmurray's Avatar Comment 30 by mmurray

Comment 27 by Universeman :

Also I am curious what impact the discovery of the God Particle will have on the theology of religions, perhaps someone would care to elaborate on this?

None. Calling it the God Particle was a silly idea

"The God particle"

The Higgs boson is often referred to as "the God particle" by the media,[36] after the title of Leon Lederman's book, The God Particle: If the Universe Is the Answer, What Is the Question?.[37] While use of this term may have contributed to increased media interest in particle physics and the Large Hadron Collider,[37] many scientists dislike it, since it overstates the particle's importance, not least since its discovery would still leave unanswered questions about the unification of QCD, the Electroweak interaction and gravity, and the ultimate origin of the universe.[36] In a renaming competition, a jury of physicists chose the name "the champagne bottle boson" as the best popular name.[38]

Michael

Sun, 24 Jul 2011 13:46:27 UTC | #853477