Re: The Pati-Salam model was the one I had in mind.
Dreaded Anomaly Send a noteboard - 24/05/2011 11:08:01 PM
Don't later models require proton decay primarily because Pati-Salam opened the door, even if the vanilla form doesn't REQUIRE it? That reduces the likelihood of other GUTs that don't also require it. I'm certainly open to them, just not aware of any save the grandaddy of all GUTs. Saying such unconceived alternatives likely lurk somewhere sounds like my argument for withholding judgement on exotic dark matter.
If you think that position tenable we may need to retrace our steps a bit. 


The two cases are not easily comparable, because the current states of evidence are very different. Also, saying the correct GUT might not yet be conceived is like saying that the correct exotic dark matter particle might not yet be conceived. GUTs and exotic dark matter are both classes of theories; saying we don't know the right one in the class isn't the same as saying we should look in another class.
In general, proton decay is a prediction of GUTs because they do away with conservation of baryon number. (You're right that Pati-Salam has this implicitly, though not explicitly.) It may just be that proton decay is very very suppressed, so the experimental half-life bounds of ~10^34 years would be acceptable. Some newer GUTs (utilizing supersymmetry, for example) make predictions that fit the experimental half-life bound. Supersymmetry corrections make the electromagnetic, weak, and strong forces all unify at a single point. Supersymmetry also predicts a new stable particle (the lightest supersymmetric particle) which could be a dark matter candidate.
I'm not sold on all of that, though I admit it has some appeal. No direct evidence yet exists. If supersymmetry is correct, we should find evidence of it at the LHC. Because of the dearth of evidence, however, this is an area where current hypotheses may just be off in the wrong direction. If that's the case, whatever actual evidence we get from the LHC should serve as a course corrector.
Exciting video about the universe
28/04/2011 10:14:55 AM
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I still think dark matter's just non-luminous matter without a convenient light source to reflect.
28/04/2011 10:34:21 PM
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We've just about ruled out the idea that dark matter is just non-luminous "ordinary" matter.
28/04/2011 11:44:34 PM
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I'm aware of the Bullet Cluster, though admittedly not much more than that.
29/04/2011 01:52:49 AM
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Re: I'm aware of the Bullet Cluster, though admittedly not much more than that.
29/04/2011 02:56:32 AM
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Re: I'm aware of the Bullet Cluster, though admittedly not much more than that.
30/04/2011 05:02:49 PM
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Re: I'm aware of the Bullet Cluster, though admittedly not much more than that.
30/04/2011 08:56:35 PM
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Re: I'm aware of the Bullet Cluster, though admittedly not much more than that.
02/05/2011 01:28:30 AM
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Re: I'm aware of the Bullet Cluster, though admittedly not much more than that.
04/05/2011 04:18:18 AM
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There's such a thing as knowing when you're licked, and I believe I am.
07/05/2011 02:04:53 AM
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Re: There's such a thing as knowing when you're licked, and I believe I am.
09/05/2011 11:28:48 PM
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Re: There's such a thing as knowing when you're licked, and I believe I am.
14/05/2011 05:36:45 AM
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Re: There's such a thing as knowing when you're licked, and I believe I am.
17/05/2011 02:09:40 AM
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Re: There's such a thing as knowing when you're licked, and I believe I am.
19/05/2011 04:55:21 AM
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Re: There's such a thing as knowing when you're licked, and I believe I am.
24/05/2011 09:32:27 PM
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The Pati-Salam model was the one I had in mind.
24/05/2011 10:34:04 PM
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Re: The Pati-Salam model was the one I had in mind.
24/05/2011 11:08:01 PM
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Re: The Pati-Salam model was the one I had in mind.
25/05/2011 01:27:10 AM
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Re: The Pati-Salam model was the one I had in mind.
31/05/2011 09:16:18 AM
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Apologies for the delay; internet's been spotty and I've been busy lately.
10/06/2011 12:09:04 AM
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Re: Apologies for the delay; internet's been spotty and I've been busy lately.
14/06/2011 03:38:18 AM
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Also, re: lensing from ordinary matter:
29/04/2011 05:18:47 AM
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This seems like another example of what confuses the issue.
30/04/2011 05:25:04 PM
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Re: This seems like another example of what confuses the issue.
30/04/2011 08:56:40 PM
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That discussion seems to reduce to "as little new and exotic physics as possible".
02/05/2011 01:29:03 AM
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Re: That discussion seems to reduce to "as little new and exotic physics as possible".
04/05/2011 04:18:24 AM
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Re: That discussion seems to reduce to "as little new and exotic physics as possible".
07/05/2011 02:05:02 AM
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Re: That discussion seems to reduce to "as little new and exotic physics as possible".
09/05/2011 11:29:36 PM
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Re: That discussion seems to reduce to "as little new and exotic physics as possible".
14/05/2011 05:35:56 AM
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Re: That discussion seems to reduce to "as little new and exotic physics as possible".
17/05/2011 02:09:55 AM
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Re: That discussion seems to reduce to "as little new and exotic physics as possible".
19/05/2011 02:47:25 AM
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Re: That discussion seems to reduce to "as little new and exotic physics as possible".
24/05/2011 09:46:30 PM
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Re: That discussion seems to reduce to "as little new and exotic physics as possible".
25/05/2011 12:20:10 AM
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Re: That discussion seems to reduce to "as little new and exotic physics as possible".
31/05/2011 09:16:22 AM
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Re: That discussion seems to reduce to "as little new and exotic physics as possible".
10/06/2011 12:04:06 AM
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Re: That discussion seems to reduce to "as little new and exotic physics as possible".
14/06/2011 03:38:12 AM
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Re: I still think... (apparently, there is a 100 character limit on subjects, and yours was 99)
28/04/2011 11:57:15 PM
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Seems to happen to me a lot; sorry.
29/04/2011 12:56:14 AM
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None of this reflects on the actual facts of dark matter.
29/04/2011 01:32:52 AM
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I concede my grasp (or grope) is a somewhat superficial laymans, yes.
30/04/2011 04:30:28 PM
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Re: I concede my grasp (or grope) is a somewhat superficial laymans, yes.
30/04/2011 08:56:44 PM
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Re: I concede my grasp (or grope) is a somewhat superficial laymans, yes.
02/05/2011 01:28:58 AM
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Re: I concede my grasp (or grope) is a somewhat superficial laymans, yes.
04/05/2011 04:18:27 AM
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I don't object to changing my mind, but can take more convincing than I really should.
07/05/2011 02:05:09 AM
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Re: I don't object to changing my mind, but can take more convincing than I really should.
09/05/2011 11:32:17 PM
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Re: I don't object to changing my mind, but can take more convincing than I really should.
14/05/2011 05:36:24 AM
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Re: I don't object to changing my mind, but can take more convincing than I really should.
17/05/2011 02:10:03 AM
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Re: I don't object to changing my mind, but can take more convincing than I really should.
19/05/2011 04:33:06 AM
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Re: I don't object to changing my mind, but can take more convincing than I really should.
24/05/2011 09:59:38 PM
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Re: I don't object to changing my mind, but can take more convincing than I really should.
24/05/2011 11:19:43 PM
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Re: I don't object to changing my mind, but can take more convincing than I really should.
24/05/2011 11:33:58 PM
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Re: I don't object to changing my mind, but can take more convincing than I really should.
25/05/2011 12:55:36 AM
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Re: I don't object to changing my mind, but can take more convincing than I really should.
31/05/2011 09:16:24 AM
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Re: I don't object to changing my mind, but can take more convincing than I really should.
10/06/2011 12:09:13 AM
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Re: I don't object to changing my mind, but can take more convincing than I really should.
14/06/2011 03:38:05 AM
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Might help if you clarified where your skepticism is at
29/04/2011 02:32:07 AM
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Potentially either, or a combination of the two.
30/04/2011 02:36:50 PM
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It's hard to discuss without knowing your objections a bit more clearly
30/04/2011 04:58:03 PM
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My primary objection is that alternatives to dark matter seem to have been ruled out prematurely.
02/05/2011 01:29:14 AM
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