Talk:Standard Model/Archive 2

Edit Proposal

In response to a statement at the bottom of this talk page, I note that there is another article at Standard_Model_(mathematical_formulation), which has a very good draft in its talk page waiting to be added to its main page. I think we should incorporate that edit there, and then move most technical details to that article (if they are not already there). Currently these articles aren't really as separated as their titles would suggest (this article contains a lot of mathematical formulation) and there's no reason to contain the same information twice! I suppose another option could be to merge, but make very clear when the technical details start. I'll wait a week in case of comments, if people agree I will proceed with my first suggestion.

I should say - I'm not a master of the subject (just PhD student) - so I wouldn't aim to make any big changes, just reorganize a bit so the general reader and the physicist know which article to read! Euan

OK, I have made the aforementioned edit, took a while as I put a lot of work into Standard_Model_(mathematical_formulation) before I felt it was ready. Of course I left some technical details here, so people don't start thinking this quantum field theory stuff is easy... :p

If anybody feels that I have moved, changed, or removed anything that I shouldn't have, let me know (of course it's Wikipedia so you can just change back to whatever you like!), but personally I think that the articles complement each other well now. A lot of the stuff I removed from this article was duplicated even within adjacent (or the same!) sections.

However I feel that this article still has a lot of questionable statements, in addition to being haphazard. I might do some work on it over the next few days. I also feel that the "history" and "tests and predictions" are scandalously brief, considering the amount of work that has gone into the SM and the amount of things it has predicted well, so if anybody wants to add to it...

Anyway, cheers guys - Euan 81.131.80.137 (talk) 21:10, 4 August 2012 (UTC)

Coding problems

This article apparently has serious coding problems and is not fully compatible with the Wikipedia formats.

Summary of interactions diagram: neutrinos and photons?

Summary of interactions between particles described by the Standard Model.

The diagram seems to imply that photons interact with the various neutrinos. As I understand it these particles are thought to interact via the weak force and do not interact via electromagnetism. Not sure if there are any theories which postulate, e.g. magnetic moments for neutrinos, and how well accepted they are in the standard model. Icalanise (talk) 18:39, 30 June 2010 (UTC)

I agree. The article also makes the mistake of counting 6 different kinds of quarks and 8 different kinds of gluons. That´s inconsistent. It should either count 18 quarks and 8 gluons or count 6 quarks and 1 gluon in order to be self consistent. Dauto (talk) 04:06, 1 July 2010 (UTC)

See "Error in diagram, proposed replacement" below. Eric Drexler (talk) 20:22, 17 April 2014 (UTC)

Should the diagram on the right say 'Strong' force, rather than 'Weak', next to the Z?

The diagram does not say weak but if added it should say weak not strong. — Preceding unsigned comment added by Jrj2222 (talk • contribs) 17:10, 12 January 2011 (UTC)

19 parameters? no Planck??

Why are parameters like, vacuum permittivity or Plancks Constant or electric charge of electron not in this list? I cant imagine we can independently set all of them equal to 1(by choosing appropriate charge unit equal to electron charge)? What more parameters like Plancks constant that are hidden from this list are there? —Preceding unsigned comment added by 157.193.8.126 (talk) 07:46, 25 January 2011 (UTC)

the speed of light and Planck's constant are not parameters; they are conversion factors. Vacuum permittivity is related to the speed of light, and the electric charge of electron is a parameter of quantum electrodynamics which is related to the standard model parameters by e = g1*g2/sqrt(g1^2+g2^2). There are no additional parameters of the standard model that are hidden from the list. The list is complete. --76.99.193.100 (talk) 14:20, 14 March 2011 (UTC)

And what about the neutrino masses? The PMNS matrix should give additionnal free parameters. I do not think we can say that the list is complete. — Preceding unsigned comment added by 193.48.90.27 (talk) 15:03, 14 July 2012 (UTC)

Monopoles ???

Where do monopoles fit into the standard model. Are they supersymmetry particles that "reflect" electrons? — Preceding unsigned comment added by 97.65.82.66 (talk) 19:28, 9 September 2011 (UTC)

No, monopoles are topological defects. Dauto (talk) 19:39, 9 September 2011 (UTC)

No thats all speculative, even though its implied by a nice symmetry (under Hodge dualization) of Maxwell's equations. If you're interested monopoles play a much bigger role in string theory, especially because of S-duality. — Preceding unsigned comment added by Isocliff (talk • contribs) 07:12, 10 September 2011 (UTC)

"upon experimental confirmation of the existence of quarks" in lede

is there no distinction between inference and observation? The general public and those with critical facilities will want to know how something which is in principle unobservable can have its existence confirmed. I think most would reject the equation of the "experimental confirmation" of electrons, protons, and neutrons with that for quarks. 72.228.177.92 (talk) 17:40, 2 November 2011 (UTC)

The evidence is certainly good enough that physicists call it "experimental confirmation," but perhaps you could change it to "extensive evidence" or something if you're worried that people will misunderstand. 2.27.105.116 (talk) 00:26, 18 July 2012 (UTC)

Right-handed particles

Do we include right-handed particles in the SM? If we do, what about the hypothetical right handed neutrinos? -- cheers, Michael C. Price ^talk 13:27, 17 November 2011 (UTC)

I'm not an expert, but after a bit of research I think the answer is no, right handed neutrinos are not included. The gauge group of the weak interaction is U(1)×SU(2)_L. Since only the left-handed representation of SU(2) is used, only left handed particles participate in the interaction. In the Standard Model, the neutrinos are massless, so the left-handed and right-handed versions (equivalent to left and right chirality in this case) should be considered as different particles. This fact is alluded to on this page Chirality (physics)#Chiral theories. However, I'm a bit confused right now about the explicit construction of the gauge fields for the nuetrinos, I have to admit. And of course, we know that neutrinos actually have mass, so technically right handed nuetrinos must exist. But any considerations of the fact neutrinos have mass is "beyond the standard model". I wonder how long before what we call the "standard model" will include the nuetrino masses. Danski14^(talk) 17:12, 1 December 2011 (UTC)

It's all in the textbooks. Handsomeransom (talk) 00:47, 8 July 2012 (UTC)

credence prior to 1977

A small change but the explanation won't fit in the minor edit summary box. The lead has: "Since then, discoveries of the bottom quark (1977), the top quark (1995) and the tau neutrino (2000) have given credence to the Standard Model." This misrepresents the level of credence prior to the discovery of the bottom quark, which was much higher than needing added credence. I cite an article from that period ( de Rújula, Georgi, Glashow "Hadron Masses in a gauge theory", Physical Review D, vol 12, p.147, 1 July 1975) "Many recent theoretical and experimental developments seem to confirm ... the "standard" gauge model of weak,electromagnetic, and strong interactions[I pasted this sentence together from the first paragraph and from the abstract]". My point is that a theory that seems to be confirmed does need more evidence to give credence to it. To keep the information in the lead about further those further discoveries, I can simply change "credence" in our lead to "further credence". Netrapt (talk) 07:47, 28 December 2011 (UTC)

Higgs boson discovery

Regarding the Higgs boson 2012 discovery mentioned in the intro: Technically, they discovered a boson, which is very likely to be the Higgs boson, but they're not sure it's the Higgs just yet. Should this be corrected? 93.173.29.43 (talk) 17:36, 4 July 2012 (UTC)

I had the same thought so I'm going to remove it. The physicists were very clear in the announcement we need more data to be sure. Phy1729 (talk) 22:20, 4 July 2012 (UTC)

So, 6 months have gone by. Have we figured out where the Higgs goes within the Standard Model diagram? Thanks! BigSteve (talk) 10:11, 5 January 2013 (UTC)

The diagram you linked to is too simplistic and not very meaningful wrt math of Standard Model (for one, the ordering of bosons in it has no relation whatsoever to the particles they couple to). As such, H boson can be put anywhere you want in that chart... 209.132.186.34 (talk) 14:11, 9 January 2013 (UTC)

Hmm... Fair enough - but I thought there was at least some sort of link - after all, the model is coherent within itself - i.e. the different particles & forces within it relate to one another. And, since it could be drawn in many ways to highlight different relationships between the bosons and fermions, I am asking where the Higgs would go in each of those different ways of drawing it. Since it has a relationship with some (or all?) of those... Thanks! BigSteve (talk) 11:55, 10 January 2013 (UTC)

The bits about dark energy

Dark energy is strictly hypothetical. I don't see why the standard model is weakened by not explaining something that might not exist. Also, this section lacks citations, and starts the article off on a bad foot. 24.165.102.99 (talk) 20:21, 4 July 2012 (UTC)Ubiquitousnewt

I wouldn't personally say that dark energy is hypothetical. True, we have no idea what it is, but it just refers to the accelerating expansion of the universe (which is definitely real and measurable)? — Preceding unsigned comment added by 2.27.105.116 (talk) 00:21, 18 July 2012 (UTC)

Yes, dark energy is still too hypothetical; at the moment it is a simple mathematical construct that fits certain observed measurements, but we have nothing that truly predicts it. It certainly does not belong in this article. — Preceding unsigned comment added by 204.86.71.226 (talk) 16:09, 18 July 2012 (UTC)

Perhaps then a better way to put it would be "does not correctly predict the accelerating expansion of the universe (Cosmological_constant#Predictions)."2.25.196.122 (talk) 20:48, 19 July 2012 (UTC)

Readability

I understand that the physics and mathematics behind the Standard Model is quite technical, but I find this article very difficult to read because of the number of technical terms provided without even a brief explanation, even with having a background in physics myself. I think the article would really benefit from a few more one-sentence explanations of specifics regarding the model in plain English. —Entropy (T/C) 16:10, 7 July 2012 (UTC)

I agree with this. Putting a comment at the top of the page... 2.27.105.116 (talk) 00:14, 18 July 2012 (UTC)

Diagram: With or without Higgs? Dotted outline?

As I understand it, the Standard Model is a theory that hypothesizes a Higgs boson. Therefore, since this article is about the theory, not our present empirical evidence about nature itself, the diagram here should include the Higgs, possibly annotated with a dotted outline to show that, unlike the others, although its status in the theory is secure, its status in nature is presently not known. I attempted to add it but someone reverted http://commons.wikimedia.org/wiki/File_talk:Standard_Model_of_Elementary_Particles.svg Thoughts? Woz2 (talk) 13:49, 16 July 2012 (UTC)

Yes, I think Higgs should definitely be included. 2.27.105.116 (talk) 00:01, 18 July 2012 (UTC)

Why on earth is "Standard Model" under the category "scientific controversies?"

I suspect no physicist would agree with such a characterization. By way of illustration, the other items in the scientific controversy page are "Extraterrestrial Life" and "Race and Intelligence". Commutator (talk) 05:19, 19 July 2012 (UTC)

Ok, that's a long enough wait with no explanation. I removed the category. Commutator (talk) 12:39, 20 March 2013 (UTC)

Cluttered Mess

1. Ever since the 'discovery' of the Higgs boson, this article has become littered with diagrams. Many diagrams are superfluous and much information can possibly be gathered into one or two diagrams. 2. Why are there so many tables which contain the same information? The (poorly formatted) table at the bottom of the article containing particle information can be removed if data appears in earlier tables. — Preceding unsigned comment added by TriTertButoxy (talk • contribs) 17:02, 29 July 2012 (UTC)

Please, be more specific. --Hugo Spinelli (talk) 06:38, 30 July 2012 (UTC)

Something missing

As a non-physicist I had trouble understanding this. Somehow physics goes from electron, protons and neutron straight to large and complicated families of particles with nothing in between. I went for what is often the easy bit - the history. Unfortunately I could not cut and paste it. But it did mention someone called Glashow. There is no explanation to what he did or how he did it or how it connects to electron etc. It does refer to an article. But most people who read Wikipedia will not have access to this. Even if they could they would not be able to understand it. Surely the whole point of Wikipedia is that someone who does know something should be able to learn a bit more and then another bit more. But this seems to be a closed shop.

john f 81.154.236.193 (talk) 07:11, 6 August 2012 (UTC)

I agree, I just split the article into mathematical / non-mathematical parts, so hopefully people could get something (if anything) out of this article, but unfortunately I'm not sure if I'll get any time to edit more in this part.

The history section, as I said above, definitely needs expansion, but the Standard Model needs a lot of background knowledge. For example, how quantum mechanics and electromagnetism lead on to (the quantum field theory of) QED, and how that is a theoretical basis on which QCD and electroweak are based. There are excellent resources on this stuff all over the place (a quick history: http://www.particleadventure.org/other/history/smt.html), but indeed it would be good if Wikipedia page could bring this all together into at least a quick, cohesive description. Unfortunately this takes a lot of work (academics don't have much time for editing Wiki!).

If you want to learn more about Standard Model, I recommend anything about QED by Richard Feynman as a start. As you say the Standard Model is a complex interplay of many particles, but that's just how the universe works - I'd say it's only just about complex enough to make life interesting for humans! Electron, proton and neutron are only a "starting point" because that's what historically we knew about first. And we didn't really understand how they worked! The fundamental theories underneath (special relativity, and you could say "quantum mechanics" although this becomes a very different beast when fitted into special relativity) could well be used to describe any number of universes (of which the Standard Model is just the one we happen to live in, according to experiments).

cheers, Euan — Preceding unsigned comment added by 217.43.215.57 (talk) 10:38, 7 August 2012 (UTC)

Isospin - hypercharge chart

A user Cjean42 has added a isospin-hypercharge chart. This is similar in flavor to Garrett Lisi's work http://en.wikipedia.org/wiki/Antony_Garrett_Lisi and to that of Carl Brannen http://orbit6.a.wiki-site.com/index.php/Image:Clr_hypercube2.gif

As much as I find it helpful, I don't believe this is a well-accepted diagram. — Preceding unsigned comment added by 68.7.12.214 (talk) 00:40, 11 December 2012 (UTC)

I withdraw my concerns, after clarifying emails with Cjean42. — Preceding unsigned comment added by 68.7.12.214 (talk) 18:09, 12 December 2012 (UTC)

Property of Separation

Allow me to add a quick direct address a property that is implied.

Charge and forces do not alone describe TOE as then there would be no model as to subatomic particles staying separate during interaction or even having space (not free to combine together like water droplets). Thus they are separate akin to electrons being unitary.

A classic discussion is: complex wave propagation v. electron charges being unitary (or resulting higgs mass being unitary).

One problem with waves is explaining why shape and style would be retained throughout atomic separation - though one problem with excluding the same is that this is how some are imperically known is imperical data gathered by separating.

Another problem with "unitary" is that by forceful interaction some are found to be combinable in some ways, ie. via neutrino bombardment. Subatomic particles are not allthroughout unitary during interaction: a resulting baryon's composition can change due to bombardment.

Thinking of force compatibility doesn't describe this as this topic is not completely known to do the necessary describing to fit the imperical data.

Another way of stating separation property as assume yet not comletely by knowing is in the color confinement article " As any two electrically-charged particles separate," (or are they? why was the origional quesiton - what keeps the unitary by observation?)

— Preceding unsigned comment added by 68.100.81.124 (talk) 18:30, 29 January 2013 (UTC)

Property of Separation Removed why?

Someone said the above was unsourced! What? Separability is a firm mathematical property that MUST be described by the model - and section Challenges indirectly mentions it.

However it's not published and new. Did I forget it's GNU/free and by me, John Hendrickson 22124? Sorry. I know that's not enough if it is a wiki complain of removal that removed the mathematical property of unitary (ie, electrons are always observed to have a constant charge - never varying from the observation, always unitary as far as we know). — Preceding unsigned comment added by 68.100.81.124 (talk) 18:35, 29 January 2013 (UTC)

Leading paragraph out of style

The following sentences does not sound like it stylistically belongs in an encyclopedia: "Developed throughout the mid to late 20th century, the Standard Model is truly “a tapestry woven by many hands”, sometimes driven forward by new experimental discoveries, sometimes by theoretical advances. It was a collaborative effort in the largest sense, spanning continents and decades."

I'm sure I can find collaborations that are larger. Also, "a tapestry" sounds just bad. It also contains redundant info ("mid to late 20th century development" already implies "effort spanning decades") I recommend removing it, without loss of flow. Or, we could replace it with "The framework was developed throughout the latter half of the 20th century as a collaborative effort of scientists around the world." 71.90.101.132 (talk) 04:10, 1 April 2013 (UTC)

I agree, I made an edit along those lines.

(I also removed a bunch of confusing/irrelevant buzzwords that had been added, despite the author's good intentions... I think they were trying to clarify the difference between particle physics and other branches of physics, so I'm going to add a sentence over at Particle physics about that.)

Euan Richard (talk) 17:23, 24 June 2013 (UTC)

Proposed Removal of Wrong Table : predicted masses of W- and Z-Bosons

In the section "tests and predictions", there is a table that shows the masses of W- and Z-Bosons, displaying an allegedly high precision. This is incorrect, since only the mass ratio is predicted by the model (the cosine of the Weinberg angle), and with an accuracy that is much inferior. I think five years are enough for an unsourced, wrong material to stay here.109.201.152.201 (talk) 20:41, 4 June 2013 (UTC)

Its still unsourced so i've moved it here :

unsourced

To give an idea of the success of the SM, the following table compares the measured masses of the W^± and Z⁰ bosons with the masses predicted by the SM:

Quantity	Measured (GeV)	SM prediction (GeV)
Mass of W± bosons	80.387 ± 0.019	80.390 ± 0.018
Mass of Z0 boson	91.1876 ± 0.0021	91.1874 ± 0.0021

Mass of photon

For pure readability reasons, I wonder if we have to say (repeatedly) that the photon has no mass at rest. This is done 3 or 4 times in the article. Are they all necessary? Student7 (talk) 22:29, 26 July 2013 (UTC)

I do not count that many. There is an instance of "would explain why the photon has no mass", which does not count. The section The relation of colour charge to electric charge for fermions is a bit strange and should be left out of the discussion. That seems to leave one. I do not think that this is excessive. — Quondum 23:20, 29 July 2013 (UTC)

I get 1)“The photon is massless”

2) “other elementary particles, except the photon …are massive.”

Immediately followed by

3) “the Higgs boson would explain why the photon has no mass” which, according to you, does not count, and

4) “The photon, having zero rest mass, carries…”

I realize that the article has been written by more than one person. Each editor thought to emphasize this point. I'm just asking if it is absolutely required in all 4 places? Student7 (talk) 00:09, 2 August 2013 (UTC)

(1) is describing a particle, and omitting this because it is tangentially mentioned elsewhere is not a natural way of doing it. Relating some other fact to the fact of the photon's zero mass is not stating that the photon is massless. (2) and (3) fall into this category; they cannot readily be restated in a way that omits the mention. (4) seems strange: here the mention of masslessness is abused (it makes no sense), and can (should) be deleted (feel free to do so); as I mentioned, the whole section The relation of colour charge to electric charge for fermions seems strange to me, and has the feel of WP:OR about it. If the section is not deleted in its entirety, it is in serious need of attention from an expert. — Quondum 00:58, 2 August 2013 (UTC)

"The theory of everything"

The following was deleted:

"It describes about 5% of the universe.(ref)[1](endref)"

"It" being the standard model. So it describes the entire known and preceived universe, anti-matter, dark matter, dark energy, etc.?

I will concede that huffingtonpost is not at the top of anyone's WP:RS, normally. But it was a secondary report from their science writer. Was s/he wrong? Student7 (talk) 22:55, 29 July 2013 (UTC)

I agree with the edit comment given with the deletion: (Out of place, out of context statement so non-specific as to be inaccurate.). The phrase not even wrong comes to mind (which is in some sense worse). — Quondum 23:06, 29 July 2013 (UTC)

The current lead states:

"The Standard Model falls short of being a complete theory of fundamental interactions because it makes certain simplifying assumptions. It does not ... predict the accelerating expansion of the universe (as possibly described by dark energy). The theory does not contain any viable dark matter particle that possesses all of the required properties deduced from observational cosmology. It also does not correctly account for neutrino oscillations (and their non-zero masses)."

The subsection "Challenges" explains this further. But no quantitative measurement of what the standard model explains is present. Student7 (talk) 17:18, 30 July 2013 (UTC)

That is as it should be. This is not an article on cosmology. Quantitative estimates of the proportion of mass that are not explained by the SM, as present at the present epoch of the universe, have no relevance here. That it fails to explain everything and is thus incomplete is relevant. — Quondum 18:39, 30 July 2013 (UTC)

Yes, but WHY does quantitative estimates of the proportion of mass that are not explained by the SM, as present at the present epoch of the universe, have no relevance here? Student7 (talk) 01:20, 1 August 2013 (UTC)

SM isn't a ToE (and bringing that up annoys the heck out of the physicists). SM+GR=ToE (if possible)Jgmoxness (talk) 01:58, 1 August 2013 (UTC)

Error in diagram, proposed replacement

The current "Summary of interactions diagram" (http://en.wikipedia.org/wiki/File:Elementary_particle_interactions.svg) includes an arc that wrongly indicates an interaction between charged and uncharged leptons. The edit history suggests that this confusion resulted from an attempt to distinguish between charged and uncharged leptons while (somehow) showing a relationship among them.

I suggest that the diagram be corrected and clarified by representing groupings (leptons, quarks, weak-force bosons) with boxes, then drawing arcs between boxes where possible to reduce the number of arcs required and reduce clutter. I've posted a version here that adds the 6 quarks in a way that parallels the 6 leptons: http://metamodern.com/Standard-Model-diagram.png This version has a little more information, less clutter, and more symmetry. Could someone knowledgeable please check it for correctness and comment here? If it passes inspection, I suggest that someone upload it and replace the current diagram. (I don't want to try to navigate the upload system.) Eric Drexler (talk) 23:08, 15 April 2014 (UTC)

I noticed another missing arc (the Z interaction with Z), and have updated the diagram above to include this interaction: It now shows that weak bosons interact with weak bosons, full stop. Note that the previous, box-free notation would be even more cluttered if this interaction were added separately, further obscuring the class-level patterns displayed by the representation that I suggest. Eric Drexler (talk) 10:54, 17 April 2014 (UTC)

Summary of interactions between particles described by the Standard Model.

Here is a cleaned up and uploaded version of a replacement for Elementary_particle_interactions.svg. It repairs three defects by removing an arc that wrongly indicates an interaction between leptons, and by including the omitted Z-Z and Higgs-neutrino interactions.

Are there any objections to making the substitution? Eric Drexler (talk) 20:25, 17 April 2014 (UTC)

Looks like a massive improvement in clarity. An observation: the lines would be shorter if the photon were moved above the w weak boson. (I'm not offering to redraw it!  :). Student7 (talk) 00:20, 22 April 2014 (UTC)

Good suggestion, and see below. Eric Drexler (talk) 12:56, 27 April 2014 (UTC)

I have an objection to my own diagram: A commenter in another discussion pointed out that neutrinos do not interact with the Higgs boson in the standard model, leaving the origin of neutrino mass a bit of a mystery. There are nonetheless two errors in the diagram currently used in the article. Eric Drexler (talk) 12:56, 27 April 2014 (UTC)

I've redrawn a corrected version that includes Student7's suggestion, and have updated the image file (make sure that you refresh your browser). Are there any objections to replacing the the buggy diagram in the article with the redrawn and corrected diagram above? Eric Drexler (talk) 14:43, 27 April 2014 (UTC)

Article updated with new image. Eric Drexler (talk) 14:29, 3 May 2014 (UTC)

Hi Eric, could you please help me understand what you mean mathematically by a "grouping"? What is the difference to an "interaction"? If we think about what fundamental vertices we can get from the SM Lagrangian, then indeed we get 3-point vertices where e+ is connected to nu_e (with W-) and so on. (The boson "self interactions" are also a little more complicated in this case e.g. http://arxiv.org/PS_cache/arxiv/pdf/0901/0901.0241v1.pdf fig. 11). Of course if we include higher-level processes, we can get any "interaction" we like! :-) I think this diagram started off with a simple implicit definition of "interaction" as just between fermions and bosons, so it may be difficult to make it consistent and comprehensive... what do you think? Thanks! Euan 157.82.231.50 (talk) 09:55, 5 September 2014 (UTC)

Diagram with hadrons is inappropriate

The article mentions hadrons as a class, but doesn't discuss their various kinds, spins, etc., and this diagram is therefore confusing and inappropriate for this article:

Particle classification. (Note that mesons are bosons and hadrons; and baryons are hadrons and fermions).

The diagram places, eg, kaons on the same level as electrons. From a fundamental physics perspective, including hadrons makes no more sense than including bound states like hydrogen, helium, and deuterium; they are all composite structures of elementary particles.

I have therefore removed the diagram. Eric Drexler (talk) 15:21, 3 May 2014 (UTC)

PMNS matrix parameters

Somebody put PMNS parameters in the table "Parameters of the standard model". Neutrino masses and mixing are not part of the standard model, and so should not be there. That information should be removed from here, and moved to PMNS matrix. --TriTertButoxy (talk) 19:02, 21 May 2015 (UTC)