tag:blogger.com,1999:blog-22973357.post2558501574218744727..comments2023-09-27T07:44:19.769-04:00Comments on Sabine Hossenfelder: Backreaction: Running Coupling ConstantsSabine Hossenfelderhttp://www.blogger.com/profile/06151209308084588985noreply@blogger.comBlogger53125tag:blogger.com,1999:blog-22973357.post-32805745751942269722013-10-06T22:55:35.662-04:002013-10-06T22:55:35.662-04:00[continuing previous comment/question]
When you o...[continuing previous comment/question]<br /><br />When you originally posted in 2007, it may have been reasonable to postulate as you did that the SUSY symbreak scale was 1 TeV.<br />But it is now 2013. We have the LHC now which is designed to run at 14 TeV. In view of this is it still tenable to contend the SUSY symbreak scale is 1 TeV? Or must we now contend it is >14 TeV? And if so, Anonymoushttps://www.blogger.com/profile/17266174550663824090noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-13391099268843511202013-10-06T22:06:26.209-04:002013-10-06T22:06:26.209-04:00"this result is to be considered one of the m..."this result is to be considered one of the most <br />compelling arguments for SUSY."<br /><br />--If this is really one of the most compelling SUSY arguments, that is utterly pathetic!!<br />(1) As piscator points out, the 3-way meet is bullshit because it is based on a redefinition intentionally designed to make it happen. <br />(2) As the post points out it depends on aAnonymoushttps://www.blogger.com/profile/17266174550663824090noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-81192239184048024282007-12-13T22:51:00.000-05:002007-12-13T22:51:00.000-05:00That could have been a possibility Survivor, but t...That could have been a possibility Survivor, but there would have been absolutely no way you would know what the new slope of the united two curves would be so as to hit the third absent knowledge about the intermediate scale physics. Not to mention its far less elegant.<BR/><BR/>No the real miracle imo isn't that the slopes hit a priori, its that the fit improves quite noticeably from the SM Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-66906678716844035852007-12-13T11:51:00.000-05:002007-12-13T11:51:00.000-05:00Hi Survivor :-) You're asking the wrong person. Co...Hi Survivor :-) You're asking the wrong person. Concealed in the above comments you might find my lack of enthusiasm about this result. Though I have to admit the plot kind of looks nice. However, here as in other cases I wonder whether our built in sense for beauty and elegance is a good guide. Best,<BR/><BR/>B.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-10950909209139851392007-12-13T11:45:00.000-05:002007-12-13T11:45:00.000-05:00Bee, please explain to me one thing... Concealed d...Bee, please explain to me one thing... Concealed down this thread, I can express my ignorance: why is it a value to have a single scale being where the curves meet, rather than two different unification scales, whereby two curves meet, then follow at another slope to meet with the third, as E increases ?<BR/><BR/>PS I do not buy the argument as evidence for anything other than a lot of work by Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-5108221390614321572007-12-12T16:48:00.000-05:002007-12-12T16:48:00.000-05:00plenty, but so far none of them worked.plenty, but so far none of them worked.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-1934003062328709972007-12-12T16:47:00.000-05:002007-12-12T16:47:00.000-05:00constantly on the run said... `Thankyou for explai...constantly on the run said... <BR/><BR/>`Thankyou for explaining the "Running Coupling Constants" to the masses. <BR/><BR/>Now please, explain the masses.' <BR/><BR/>Any ideas why the particles have the masses they do?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-56894016683955579072007-12-12T15:32:00.000-05:002007-12-12T15:32:00.000-05:00Hi Alex:Thanks for the interesting discussion, I c...Hi Alex:<BR/><BR/>Thanks for the interesting discussion, I certainly learned something! Best,<BR/><BR/>B.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-53455105273059434282007-12-12T13:53:00.000-05:002007-12-12T13:53:00.000-05:00I said: "The unification of the couplings alone do...I said: "The unification of the couplings alone does not guarantee that if you run the ratio up to the GUT scale you'll get a match with the prediction sin^2(\theta)=3/8."<BR/>Ok, now that I've thought about it carefully, I have to admit that the above statement is wrong. You are right that as long as the couplings unify you always get the match for the Weinberg angle, no matter at what scale andAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-78138420753829441842007-12-12T13:16:00.000-05:002007-12-12T13:16:00.000-05:00"What I am saying all the time is if a_1/a_2 has t..."What I am saying all the time is if a_1/a_2 has the correct value at the EW scale then doesn't the Weinberg angle follow from that, so in how far is this 'another impressive prediction' (besides not being a prediction that is)."<BR/><BR/>Computing the Weinberg angle at the EW scale tells you nothin illiminating about the underlying GUT theory. In order to compare it with the value predicted by Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-81373410642476182722007-12-12T12:07:00.000-05:002007-12-12T12:07:00.000-05:00No is does not necessarly follow. You can have uni...<I>No is does not necessarly follow. You can have unification and not get the agreement for the Weinberg angle.</I><BR/><BR/>But I never said that. What I am saying all the time is if a_1/a_2 has the correct value at the EW scale then doesn't the Weinberg angle follow from that, so in how far is this 'another impressive prediction' (besides not being a prediction that is). I am not interested in Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-54410225199591931112007-12-12T12:01:00.000-05:002007-12-12T12:01:00.000-05:00"I.e. what I am saying is B follows from A"No is d..."I.e. what I am saying is B follows from A"<BR/><BR/>No is does not necessarly follow. You can have unification and not get the agreement for the Weinberg angle. It is only when you have the MSSM spectrum ONLY all the way to the GUT scale do you get the agreement with sin^2(\theta)=3/8.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-65037904676317461452007-12-12T11:53:00.000-05:002007-12-12T11:53:00.000-05:00thinking about it again, it seems you are actually...thinking about it again, it seems you are actually saying C does not follow from B. Translate A -> ratio of a_1/a_2, B -> sin^2 theta, C -> unification of couplings.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-71158393251729167442007-12-12T11:45:00.000-05:002007-12-12T11:45:00.000-05:00Oh, and you can imagine another scenario. Suppose ...<I>Oh, and you can imagine another scenario. Suppose you add extra matter in complete GUT multiplets to the MSSM somewhere </I><BR/><BR/>I was not talking about other scenarios. I am pretty sure if one adds further parameters, on can fit further parameters independently.Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-82419673020334027672007-12-12T11:42:00.000-05:002007-12-12T11:42:00.000-05:00Hi Alex:Thanks for agreeing that it's fixing the G...Hi Alex:<BR/><BR/>Thanks for agreeing that it's fixing the GUT scale that gives the right Weinberg angle. Regarding the question of whether it is 'another prediction'. It seems I have made myself somewhat unclear so let me try it again. <BR/><BR/><I>Alex: So do you see how one feature, i.e. the unification of couplings is not necessarily correlated with the other (the correct ratio of alpha_1/Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-11951210048016853792007-12-12T11:38:00.000-05:002007-12-12T11:38:00.000-05:00Oh, and you can imagine another scenario. Suppose ...Oh, and you can imagine another scenario. Suppose you add extra matter in complete GUT multiplets to the MSSM somewhere in between the EW and the GUT scale. In that case you still have the unification of all three couplings but the Weinberg angle at the GUT scale would not match the value 3/8. So, having the MSSM only spectrum all the way to the GUT scale is crucial in getting the agreement.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-86348109106309614512007-12-12T11:14:00.000-05:002007-12-12T11:14:00.000-05:00"Well, if the angle runs when you go DOWN it seems..."Well, if the angle runs when you go DOWN it seems to me its value depends on how far you let it run. Since the GUT scale is an input parameter, can't you just shift the start point of the running around such that at the EW scale the value comes out right?"<BR/><BR/>Sure, so you choose the GUT scale to get the right value for sin^2(\theta) and get agreement. But then you also take the Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-69409430896140929582007-12-12T11:02:00.000-05:002007-12-12T11:02:00.000-05:00"You are saying one could have theta being correct..."You are saying one could have theta being correct without having alpha_1/alpha_2 correct."<BR/><BR/>No, I was saying that sin^2(\theta) is fixed by the embedding of the U(1) into the SU(5) and does not care if ALL THREE couplings unify. You can get alpha_1 and alpha_2 to cross at a point and get the right value of sin^2(\theta) WITHOUT alpha_3 crossing at the same point.<BR/>Just add some Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-82166380025636761982007-12-12T08:14:00.000-05:002007-12-12T08:14:00.000-05:00Hi Thomas:I think you are talking about the differ...Hi Thomas:<BR/><BR/>I think you are talking about the differences of the neutrino masses, not the absolute masses.<BR/><BR/>Hi Alex:<BR/><BR/><I>So do you see how one feature, i.e. the unification of couplings is not necessarily correlated with the other (the correct ratio of alpha_1/alpha_2)?</I><BR/><BR/>Actually, no. You are saying one could have theta being correct without having alpha_1/Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-61701194479604074812007-12-12T02:46:00.000-05:002007-12-12T02:46:00.000-05:00Moreover, by the seesaw mechanism, the electroweak...<EM> Moreover, by the seesaw mechanism, the electroweak scale comes out to be the geometric mean of the GUT scale (predicted by the running) and the neutrino mass scale, which puts the neutrino mass in O(1eV) range - consistent with experimental bounds.</EM><BR/><BR/>Aren't neutrino masses rather in the 10^-3 - 10^-2 eV range, so the EW scale is the geometric mean between the Planck and neutrino Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-36811498742293836502007-12-12T01:01:00.000-05:002007-12-12T01:01:00.000-05:00Thankyou for explaining the "Running Coupling Cons...Thankyou for explaining the "Running Coupling Constants" to the masses. <BR/><BR/>Now please, explain the masses.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-33484223955624318112007-12-11T22:36:00.000-05:002007-12-11T22:36:00.000-05:00"Then we run them DOWN..."Oops, I meant run it (si..."Then we run them DOWN..."<BR/>Oops, I meant run it (sin^2\theta) down...Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-59305640849733334382007-12-11T21:19:00.000-05:002007-12-11T21:19:00.000-05:00"Isn't 3/5 tan^2 theta just alpha_1/alpha_2?"Yes, ..."Isn't 3/5 tan^2 theta just alpha_1/alpha_2?"<BR/><BR/>Yes, it is. <BR/><BR/>"In how far is this actually another prediction?"<BR/><BR/>So, in order to make a "real prediction" from a susy GUT one would have to find a parameter that could be directly computed in the GUT theory. Since we cannot compute the value of alpha_GUT from first principles yet, we can instead reliably compute the ratio of Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22973357.post-58071509656400246192007-12-11T19:31:00.000-05:002007-12-11T19:31:00.000-05:00Hi Alex:I forgot to mention another impressive pre...Hi Alex:<BR/><BR/><I>I forgot to mention another impressive prediction from SUSY GUT's, namely the value of the Weinberg angle. </I><BR/><BR/>In how far is this actually another prediction? Isn't 3/5 tan^2 theta just alpha_1/alpha_2? <BR/><BR/>Best,<BR/><BR/>B.<BR/><BR/>PS: Completely off topic, I just heard an advertisement on the radio for the 'four course Italian fest', announced with Sabine Hossenfelderhttps://www.blogger.com/profile/06151209308084588985noreply@blogger.comtag:blogger.com,1999:blog-22973357.post-17456439274211643982007-12-11T17:23:00.000-05:002007-12-11T17:23:00.000-05:00"Is this specific to susy GUTs?" The GUT scale val..."Is this specific to susy GUTs?" <BR/>The GUT scale value is fixed by group theory. I think the value for SU(5) is sin^2(\theta)=3/8, if I recall correctly.<BR/><BR/>The presence of superpartners in the spectrum affects the running of sin^2(\theta) and hence, its value at the electroweak scale. The experimental value measured at the EW scale is sin^2(\theta)~0.2312.<BR/><BR/>So, for an SU(5) Anonymousnoreply@blogger.com