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Author Topic:   Higgs Boson
Son Goku
Inactive Member


Message 13 of 81 (666509)
06-28-2012 8:39 AM
Reply to: Message 12 by Trixie
06-28-2012 8:06 AM


Re: Rumours
Okay, gossip in the physics community (you heard it here first on EVC!), the Higgs has probably been found. CERN is going to make an announcement on July 4th.

This message is a reply to:
 Message 12 by Trixie, posted 06-28-2012 8:06 AM Trixie has replied

Replies to this message:
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 Message 15 by Trixie, posted 06-28-2012 5:06 PM Son Goku has replied
 Message 16 by Tangle, posted 06-28-2012 5:58 PM Son Goku has not replied
 Message 17 by Tangle, posted 06-28-2012 6:00 PM Son Goku has not replied
 Message 20 by Straggler, posted 06-29-2012 7:41 AM Son Goku has not replied

  
Son Goku
Inactive Member


Message 21 of 81 (667000)
07-02-2012 6:12 AM
Reply to: Message 15 by Trixie
06-28-2012 5:06 PM


Re: Rumours
I'll explain about the Higgs in seperate post, maybe in coffee house, since more people post there.
For now I'll say that what I've heard is the CERN have definitely found a boson with the same properties as the Higgs in the same type of reactions (photon interactions) where you expect to find the Higgs.
This boson has been found with 99.99995% confidence. In the next few months they will need to check if it is indeed the Higgs (by looking at other reactions) or a new and completely different boson that happens to look like it in photon interactions.

This message is a reply to:
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Son Goku
Inactive Member


(1)
Message 23 of 81 (667202)
07-04-2012 3:49 AM


Higgs
A new Higgs-like particle has been found with over five sigma confidence at the Compact Muon Solenoid in CERN. At 8:38 a.m. today the announcement was made.

  
Son Goku
Inactive Member


(1)
Message 24 of 81 (667203)
07-04-2012 4:01 AM


More info.
Technically accurate results just there now.
The sigma value is at 4.9 under the most stringent testing. This corresponds to being:
99.9999% confidence that a new boson has been detected at the Compact Muon Collider. Its mass is 125.3 (+- 0.6) GeV, or :
0.0000000048 grams.

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Son Goku
Inactive Member


(1)
Message 26 of 81 (667205)
07-04-2012 5:49 AM


ATLAS
My first posts were for the CMS (Compact Muon Solenoid).
The results from ATLAS:
They have independently found a new boson with over five sigma confidence. 99.99994% confidence.
The new boson is a Higgs with 4.6 sigma confidence. 99.9996% confidence.

  
Son Goku
Inactive Member


(3)
Message 39 of 81 (667680)
07-11-2012 6:15 AM
Reply to: Message 38 by foreveryoung
07-11-2012 4:31 AM


Re: Rumours
The statistics in particle physics experiments have a simple enough origin in this case.
For instance in the case of the search for the Higgs, we see a bump in the two photon channel. This means that around 125 GeV slightly more photons were being produced than the energies around it, the hypothesis is that these extra photons come from the decay of the Higgs boson.
However it is possible that extra photons were produced simply by chance without the Higgs. So you compare the results against the scenario where the photons are produced by chance. It then turns out that such a bump has only a 0.00005% chance (1 in 2 million) chance of occurring randomly. Hence it is overwhelmingly likely to be a Higgs.

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 Message 38 by foreveryoung, posted 07-11-2012 4:31 AM foreveryoung has replied

Replies to this message:
 Message 40 by foreveryoung, posted 07-11-2012 11:51 AM Son Goku has replied

  
Son Goku
Inactive Member


(4)
Message 44 of 81 (667767)
07-12-2012 4:12 AM
Reply to: Message 40 by foreveryoung
07-11-2012 11:51 AM


Re: Rumours
Why is it the science community all convinced this "something" is their long sought after higgs boson?
The reasons are as follows:

  1. The relation between the width of the bump and the height of the bump produced in the two photon channel matches the Breit-Wigner profile for a decaying relativistic particle.
  2. The particle is scalar (immediately obvious from the channel it was discovered in) and carries no spin, the Higgs has spin-0
  3. The particle has weak isospin of 1/2, just like the Higgs is expected to.
  4. It was found inside the expected mass range of the Higgs
  5. It has decay rates in other channels (decaying into leptons, e.t.c.) at the rate expected of the Higgs.

Now as Dr. Adequate has said you will still see people say that the particle is "Higgs-like" or "a Higgs". This is because the Higgs is a particle produced after the Electroweak Force broke into the Electromagnetic and Weak Nuclear Forces. However, depending on what exact mechanism separated the forces the Higgs will be slightly different, even though it will always obey the points 1. - 5. above.
The simplest mechanism is the one proposed by Higgs, Anderson, Englert, Brout and Kibble back in the 1970s. This version of the Higgs is usually known as "the Higgs" or "the Standard model Higgs".
Other mechanisms produce slightly different Higgs bosons, sometimes called "Higgs-like" or "a Higgs".
The main aim now is to find which one of the four candidate mechanisms is true (a fifth one has already been ruled out and there aren't others because these are really the only ideas consistent with quantum field theory).
Edited by Son Goku, : No reason given.
Edited by Son Goku, : Editing

This message is a reply to:
 Message 40 by foreveryoung, posted 07-11-2012 11:51 AM foreveryoung has replied

Replies to this message:
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Son Goku
Inactive Member


(4)
Message 45 of 81 (667768)
07-12-2012 4:16 AM
Reply to: Message 43 by foreveryoung
07-12-2012 2:41 AM


Re: Rumours
foreveryoung writes:
Does a boson of any flavor even have any mass?
Several bosons have mass. The W bosons, the Z bosons, the eta meson, the eta prime meson, there are hundreds. A boson is any particle whose spin (a measure of how much the particle is rotating about its axis, if you want a classical picture) is a whole number.
I don't subscribe to the standard model of particle physics.
For what reason?
What is your definition of a particle anyway?
The proper definition of a particle is very abstract and requires some background exposition in quantum mechanics. I can do so, if you wish.

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 Message 43 by foreveryoung, posted 07-12-2012 2:41 AM foreveryoung has replied

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Son Goku
Inactive Member


(11)
Message 50 of 81 (667838)
07-12-2012 4:11 PM
Reply to: Message 46 by foreveryoung
07-12-2012 1:06 PM


Re: Rumours
Well we know there are two forces, the electromagnetic force and the weak force. The carrier of the electromagnetic being the photon and the carriers of the weak force being the two W bosons and the Z boson.
Since the W bosons carry electric charge we know that the two forces are related in some way. The idea arrived in the 70s was that this was because they were originally one force, the electroweak force.
Unfortunately if you write down the equations for the electroweak force, relativity and quantum mechanics demand everything should be massless. Which they obviously aren't.
The only possible way around this is to have something which breaks the symmetry associated with the electroweak force. According to the theory certain interactions even though they involve different numbers and species of particles have the same probability of occurring. This is the symmetry I'm speaking of.
Any mechanism which reduces the symmetry to a smaller set of symmetries will natural cause the force to split in two and give the W bosons and the Z boson their mass.
The mechanism has to involve a field with no spin, any other type of field would not only reduce the electroweak symmetries but also break relativity, which we know observationally to be false. This is the reason for the spin-0 condition.
If it had any weak isospin other than 1/2, then too much of the symmetry would be broken. Weak Isospin can be 0, 1/2 and 1. Weak Isospin-0 wouldn't break the symmetry and Weak Isospin-1 breaks it too much, leaving behind two electromagnetic forces rather than an electromagnetic force and a weak force
The Higgs can't have a mass too high due to quantum triviality. Basically if you put a mass higher than a certain value in the equations, all the interactions of the Higgs field with the other fields immediately become zero. Since it doesn't interact, then it can't break the symmetry, so it must be beneath that mass.
Its decays and interactions are naturally controlled by the rules of quantum field theory once the three properties above (spin-0, Weak Isospin-1/2 and low mass) are in place. No other decays are possible under quantum mechanics and relativity.
So:
(a) Spin-0 demanded by relativity
(b) Weak Isospin-1/2 demanded by observations (we don't have two electromagnetic forces)
(c) Low mass demanded by quantum triviality
(d) Interactions fixed by quantum mechanics and relativity.
So the Higgs has to look like this or quantum field theory would be wrong in some way.
And now we've found a boson with exactly those properties.
Edited by Son Goku, : Some editing.

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 Message 46 by foreveryoung, posted 07-12-2012 1:06 PM foreveryoung has replied

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 Message 53 by foreveryoung, posted 07-19-2012 2:00 AM Son Goku has replied

  
Son Goku
Inactive Member


(12)
Message 58 of 81 (668263)
07-19-2012 7:18 AM
Reply to: Message 53 by foreveryoung
07-19-2012 2:00 AM


Maybe you're wrong! x10
foreveryoung writes:
There is no such thing as a photon.
Why do detectors pick up isolated objects with spin-1 when they analyse a beam of light?
Particles don't carry forces.
Well it would be more accurate for me to have said that the field which causes the electromagnetic force is associated with photons and the weak nuclear fields are associated with the W and Z bosons.
The first mistake is assuming that quantum mechanics describes reality in any meaningful way.
You're not really making any valid points, you're just constantly say "maybe you're wrong".
Sure "maybe" quantum mechanics is incorrect, but from all experimental evidence it doesn't seem to be and at the moment that's a huge amount of experimental evidence.
Do you have anything concrete to suggest it's wrong.
Symmetry associated???? That sounds like mathematical games to me.
Do you have anything more developed to say. Think about about it, the Standard Model is tested everyday in nuclear reactors and accelerators and it provides the full explanation for the energy production of the sun and several other physical processes. The fact that it sounds silly to you is of no consequence, unless you have an actual developed criticism.
How would they know if they have the same probability of occurring?
The theory predicts it and experiments observe it.
How would they know this?
It's what quantum field theory predicts and its consequences have been experimentally verified. Cosmological observations have verified it as well.
There is something obviously wrong with the standard model and/or quantum mechanics for there to that much matter and energy to be unaccounted for. Just because a theory has nice mathematics and makes good predictions, doesn't mean it accurately represents reality.
I think you have an incorrect perception of the Standard Model.
The Standard Model wasn't created to explain everything, it was created to explain the electromagnetic, weak nuclear and strong nuclear forces. Based on experiment it seems to do that pretty well.
There are things it doesn't describe, like Dark Matter, but that doesn't mean it doesn't reflect the reality of the three forces it does try to describe.
For example the theory of photosynthesis tries to explain the production of chemical energy in plants. It doesn't describe what happens chemically in animals, but that doesn't mean it doesn't reflect reality.
I suppose the usually suspects will be here shortly to jeer me to death because I upset their apple cart.
You haven't upset anything, as your criticisms don't really say anything, just:
"Maybe you are wrong!"
without any reference to the actual experimental evidence which suggests we're at least somewhat right.
Edited by Son Goku, : Spelling mistake.

This message is a reply to:
 Message 53 by foreveryoung, posted 07-19-2012 2:00 AM foreveryoung has replied

Replies to this message:
 Message 60 by foreveryoung, posted 07-19-2012 12:59 PM Son Goku has replied

  
Son Goku
Inactive Member


(3)
Message 63 of 81 (668308)
07-19-2012 3:06 PM
Reply to: Message 60 by foreveryoung
07-19-2012 12:59 PM


Re: Maybe you're wrong! x10
foreveryoung writes:
They pick up a pulse in an electromagnetic wave. The spin comes from what phase the wave is in.
There are a few things wrong with this, let's take the most glaring problem first.
The spin, which is basically just angular momentum always comes in multiples of . If light was just a wave, then couldn't the strength of the wave be adjusted continuously to get any amount of angular momentum you wanted. Why is it always with a whole number?

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Son Goku
Inactive Member


Message 66 of 81 (672291)
09-06-2012 5:28 AM


Update.
The data has been checked more extensively and in addition to the 5.9 sigma result mentioned above, it seems the new boson has the same decay properties as those predicted for the Higgs. What remains is to measure those decay properties more exactly, since currently the boson could still be some other particle. Also, more importantly, we need to measure the parity of the new boson.
Parity only comes in two values (-,+) which describes how the field related to the particle behaves if you look at it in a mirror. Although the profile of the field will be inverted, like any everyday object, its also possible that its values at each point in space could change sign, that is flip from positive to negative values and vice-versa. + being that they don't change sign, - being that they do. The Higgs field has parity +, the effects of which will show up in the scattering of the Higgs boson off other particles.

Replies to this message:
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