Timeline for Why are all observable gauge theories not vector-like?
Current License: CC BY-SA 3.0
16 events
| when toggle format | what | by | license | comment | |
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| Aug 9, 2012 at 23:35 | vote | accept | Argus | ||
| Jul 10, 2012 at 6:01 | history | edited | Argus | CC BY-SA 3.0 |
clarified title, aded more specific background with links.
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| Jul 7, 2012 at 20:37 | comment | added | Ron Maimon | @Argus: ok, "why are there no vectorlike gauge bosons observed in nature". The answer to the why is theoretical--- there is no inconsistency in having them, it's just ridiculous fine-tuning. | |
| Jul 7, 2012 at 19:59 | comment | added | Argus | @ron If I may state there is only observation in physical science I expressly do not take into account "theory" when asking this question. | |
| Jul 7, 2012 at 19:34 | answer | added | Ron Maimon | timeline score: 4 | |
| Jul 7, 2012 at 19:18 | comment | added | Ron Maimon | Your question should be retitled "why are there no vectorlike gauge theories in nature". | |
| Jul 7, 2012 at 19:11 | comment | added | Ron Maimon | @Argus: It's not only false that Fermions require mass, it is true that fundamental low energy Fermions start out massless, otherwise why don't they have a Planck scale mass? If we found a vectorlike gauge theory in nature, it would be a Fermion heirarchy problem. There are no vectorlike gauge theories in nature (I don't like this obfuscating and obsolete 1950s terminology "vector-like", just say "Gauge theory which Fermions which aren't partnered to be massive"). The correct statement is that no fundamental theory in nature is vector-like, and this is a conseqence of naturalness. | |
| Jul 7, 2012 at 13:01 | comment | added | Argus | @ron Can a mass be worked out for all fermions or do they "not" require mass. Specifically how can we explain the standard model as not vector-like (and still call it the standard model which implies that standard gauge theories are not vector-like) | |
| Jul 7, 2012 at 6:45 | comment | added | Ron Maimon | Can you ask the question another way--- this is unanswerable. What is the question exactly? If you are asking "what are the conditions for a consisent gauge theory with fermions" the answer is anomaly cancellation. If you are asking "what happens to fermions that can't have a mass" the answer is "they don't have a mass". But I can't understand what the question is exactly. | |
| Jul 1, 2012 at 20:32 | comment | added | Argus | @djbunk: trying to ask both but answering one leads to the answer to the other. But specifically since you asked Why the standard model is not vector like and does the use of higgs mechanism help break this symmetry | |
| Jul 1, 2012 at 20:30 | comment | added | DJBunk | Are you asking (1) why every conceivable gauge theory is not vector-like? Or (2) why the standard model is not vector like? As for (1) I can certainly write down a vector-like gauge theory (QED). As for (2) talk to God. | |
| Jul 1, 2012 at 16:01 | comment | added | Qmechanic♦ | Comment to the question(v2): Note that not all gauge theories are of (Abelian or non-Abelian) Yang-Mills type, cf. physics.stackexchange.com/q/8686/2451 | |
| Jul 1, 2012 at 3:30 | comment | added | Argus | @ChrisGerig: I edited the question with some background. | |
| Jul 1, 2012 at 3:30 | history | edited | Argus | CC BY-SA 3.0 |
background
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| Jul 1, 2012 at 3:25 | comment | added | Chris Gerig | I don't even know what that first question means... please explain. | |
| Jul 1, 2012 at 3:05 | history | asked | Argus | CC BY-SA 3.0 |