## Sunday, July 08, 2012 ... //

### Buckley, Hooper: Higgs decay deviations due to $$300\GeV$$ stop squarks

We may already be looking at the first signs of supersymmetry at the LHC

No one was too interested in the Higgs $500 bet I won – and was paid yesterday – but I have a more interesting outstanding bet against Adam Falkowski in which I would win$10,000 if supersymmetry is found.

Of course, the actual value of supersymmetry as a clever idea indisputably working somewhere in the foundations of Nature is higher by orders of magnitude.

However, I would only lose $100 if it is not found. You must be a true fundamentalist if you bet 100-to-1 in a bet about top-down particle physics, moreover against a person who knows 100+ times more about these issues than you do – and yes, I mean against your humble correspondent. Physics Central has brought the readers' attention to the strongest evidence yet that indicates that I may very well win the bet: First the Higgs, Next Supersymmetry? It is about a preprint that will become visible on Sunday night. I will only read it on Mondary morning, European time. Dan Hooper and Matthew Buckley, two powerful enough particle physicists at the Fermilab, have looked at the deviations of the observed Higgs decays from the predictions of the Standard Model. What is the vertict of their paper called "Are There Hints of Light Stops in Recent Higgs Search Results?" [link added on Monday morning] The most obvious candidates are partners of the top partner, such as stops within the context of supersymmetry. We find that the presence of such a particle can easily modify the Standard Model Higgs widths in such a way to come within approximately one standard deviation of the observed values. This blog has been talking about the LHC stop squark rumors since February 2012 and this excitement hasn't gone away. A fascinating detail of the coming Buckley-Hooper paper is that the best fit is obtained if the stop squark mass is near $$300\GeV$$. This just happens to be the same mass I mentioned just two days ago in a blog entry on the CMS top partner conspiracies. Recall that they greyed out this region of their chart where a signal was pretty clearly present, invented an excuse, and argued that a more than 3-sigma excess means "no excess". In this CMS search for bosonic top partners (which mostly means stop squarks), an exclusion curve was expected (thick red plus minus thin red errors) but no exclusion could have been deduced from the observations. Moreover, points such as $$m_{\rm stop}=300\GeV$$ and $$m_{\rm LSP}=140\GeV$$ have been "grayed out" with a strange excuse: allegedly unpredictable initial state radiation. If you click at the link, the #1 hit just happens to go to the website of a person who is both a member of the CMS statistical committee as well as a fanatical anti-supersymmetric fundamentalist. According to the prevailing logic in supersymmetry, a light stop squark is essential for the light $$126\GeV$$ Higgs to remain natural. The possibility that a $$300\GeV$$ stop squark is beginning to emerge in front of our eyes strikingly contrasts with the preposterous claims by some people that the LHC has excluded any superpartners up to $$1\TeV$$. Be sure, it hasn't. Some SUSY models look more viable than others but none of the important classes has been quite excluded yet. #### snail feedback (37) : reader Shannon said... I have a good feeling about all this :) (OT : it's the European Science Festival in Dublin this week and I'll attend Brian Greene talk on Thursday ! Yesterday it was a Fields medalist who talked about Poincaré and also the Boltzmann equation. I'm spoiled!) reader Dilaton said... Ha ha, Shannon, you make me really jealous ... :-D! Cool that you are live at this science festival and can see cool talks by awful physicists; I wish you a lot of fun :-) reader Dilaton said... Lumo, your bets are sooo cool, it alway makes me chuckle thinking about them and I want you to win all of them ... ;-)!!!. Your living room looked very nice indeed :-D The announcement of this new paper makes me very happy and excited, in particular because it could nicely expose what CMS is trying to hide ... :-D. I almost cant hold back posting a happy "Bazinga !!!" together with a link to the Physics Central (or better this TRF ?) article on TDs blog ... :-P ;-) :-D (But I`ve sworn to no longer click him ...) reader Dilaton said... ... I mean I look forward to honestly and sincerely wish TD and even PW a "Happy STOP Day" ... :-D reader Mephisto said... "moreover against a person who knows 100+ times more about these issues than you do – and yes, I mean against your humble correspondent" yes, humble indeed :-)))) reader Luboš Motl said... It's how I was brought up. When you're 500+ times better at something, just say modestly 100+, the jealous people will prefer it. reader Eugene S said... (cough, cough...) I think you meant "awesome" :) reader Dilaton said... Whoops yep thanks ... ;-) reader campistanonimo said... Why some "anti-supersymmetric fundamentalist" would try to hide something that inevitably will appear some months from now and he would looks like an idiot? Doesn't even makes sense. reader Luboš Motl said... Because he would look like an idiot (more precisely, his being an idiot would be unmasked to plain sight) already now and he wants to delay this point, and indefinitely if possible. ;-) That happens in many contexts. Unfortunately. reader NumCracker said... Dear Lubos, for how long we will have to wait till LHC has enough data to validate/exclude "The usual Higgs" Boson? Suppose it is validated (in all 5 observed channels) could it be used to indirectly exclude a 300 Gev sTop? Thanks reader Luboš Motl said... It will be getting more and more accurate. After the 2012 run which will end in early 2013 according to the newest plan, they should have up to 30/fb in total for each detector, including 2011, as opposed to 10/fb now. So all signals will grow sqrt(3) times, relative errors in cross sections will drop sqrt(3) times, and so on. I don't know which way they will go. It seems plausible that after 2012, if a 300 GeV stop isnt' there, it could be possible to exclude it just from the Higgs decays. reader Cliff Harvey said... That chart is pretty striking, and so is the excuse. I wonder if we'll see a version of this chart with 2008 data by SUSY 2012 in August. It sounds like that one should be dramatic, with the extra TeV and twice the integrated luminosity. reader Shannon said... Thanks Dilaton. Still I'll be missing Lisa Randall, and another talk from Greene on the State of String Theory. But I know I'm not really missing anything because I have TRF ;-) reader Cliff Harvey said... By the way, I missed the part where it was explained how to change my Disqus icon.... Apparently not under any of the menus anywere haha? reader Dilaton said... Hi Cliff, are you registered and logged in? Then you should see below your comment box a horizontal menu bar with some kind of a gear-wheel on the far right. From this you can choos "Edit Settings" to make a window popping up that lets you edit your profile settings. The avatar picture is among the things you can change, you can just upload one from your PC. I hope this helps ... and cool to see you here again ;-) ! reader Penguin said... If you look at Fig 5 in the CMS SUS-12-009, you see that their observed limits lie only slightly more than 1 sigma above their expected limits. Believe me, I hope it is real and it turns into a real signal, but I wouldn't bet the house on a 1.x sigma excess. reader James Mayeau said... If you figure it out, please let me know. Cause I'm stuck with my street name. There must be a painless way to change back into papertiger. reader Luboš Motl Not Papertiger said... Hi papertiger, haven't I already told you? At the top of this DISQUS thread, there is "Discussion, Community, My DISQUS". On the right side from that, in the right corner, there is a little triangle/arrow. Click it and choose edit settings. The displayed name may be modified in "Profile" and there's also "Avatar" over there, Cliff. Assuming you are using a real DISQUS account. reader iya said... It looks like they either forgot to put in the observed curve, or maybe deliberately took it out, because it's not even present in the legend. In similar ATLAS plots, the values in the lower left corner are not censored, but I don't quite understand what they actually imply. Is it the models cross section? It's a "known" parameter and not part of the data, so it shouldn't be too controversial, right? reader NumCracker said... Lubos, can you elaborate more on such paper? Considering Chi^2/d.o.f is this kind of fit-proposal favoured when compared to SM ? reader Marc said... Lubos---the paper is now out. However, three papers down the list is an analysis by Djouadi claiming that when one properly includes QCD uncertainties in gluon fusion, the discrepancy in the gamma-gamma rate drops to just one sigma. Still, I'm glad to see Buckley and Hooper's paper, in case the significance grows. reader Anonymous said... Dear Marc, so you mean that this is The SM Higgs and nothing more? Oh Gosh ... this would be a nightmare! reader iya said... From the paper: ...assuming no unknown systematics, we ﬁnd that the best ﬁt values for the Higgs widths to photons and gluons is preferred over those predicted by the Standard Model at greater than 99.9% conﬁdence [...] suggesting the presence of new, strongly coupled physics present well below the TeV scale. It seems that only a potential loose cable is standing between Luboš and$10,000.

reader James Mayeau said...

Yeah, I'm sure you did, but it didn't work the last time either.
I clicked the gear. Got a drop down list with my name, a link to the complaint dept., and a logout.
No edit option.

Maybe I have the same problem as Cliff. Maybe I have the DISQUS beta version or something.

Don't worry about it. Unless you know what the problem is already, no need to study up or apply your time to figuring it out.
You have important things to do, like cleaning up the money in the living room, or solving mysteries of the galaxy.

I'll make due.

reader Luboš Motl said...

Dear iya, sounds great ;-), unfortunately I see many more possible dark clouds ahead, including new strongly coupled matter fields unrelated to SUSY and totally different explanations such as one mentioned by Marc right above your comment...

reader Luboš Motl said...

Dear papertiger, this comment of yours hasn't been posted via any DISQUS account at all. You posted it via your Google-plus account where you either can't edit the displayed name or it is done elsewhere. I wouldn't be surprised if it turned out that you haven't created a DISQUS account at all yet. When you're posting comments here, you must choose "D" as DISQUS from the list of possible identities.

This is a good clue,
yes! Back 'n business.
Mr Motl, thank you for giving me back my face. (he really is 500+ times better). ;)

Oh btw what I did. Logged out of the google. Then logged in under the DISQUS tab to access the options menu. Nothing to it.

reader Luboš Motl said...

Dear Numcracker, the paper contains what I expected. They need a light stop, maximum mixing so that the mixed/interference term really dominates and one may send the gamma-gamma coupling down. The authors obviously think it's very hard to reduce the rate but they have a solution.

Their best fit with a stop squark is "unnecessarily too good" so they have "overfitted it" - what they're trying to ideally reproduce is partly noise, not signal. But unlike Nanopoulos et al., there is a case to be made here that the agreeement with the Standard Model really starts to be poor - the overall deviations seem to exceed 2 sigma. In the case of Nanopoulos et al. ("aroma" papers on SU(5) Flipped F-theory models), the discrepancy was just 1.5 sigma or so, too small.

We will see whether the deviation gets stronger. If it does, indeed, it seems rather hard to construct models that may move the branching ratios in the right direction. There will probably be more papers by famous authors that may claim a similar thing but I can't tell you more details.

reader Luboš Motl said...

Dear Penguin, this paper is only based on the 2010 data, 35 inverse picobarns of data! This has nothing to do with the latest experimental work in search for SUSY which is based on 300 times greater datasets.

BTW, why is it so hard for phenomenologists to design such model who could move the the branching ratios in the right direction?

reader Luboš Motl said...

Dear NumCracker, good question. Try to look at the new 300 GeV stop squark paper. You will see that the normal terms are positive. Only a mixed term - coming essentially from destructive interference - is negative.

Intuitively, the Standard Model is a "subset" of any broader theory and the diphoton decay rate in the Standard Model is the minimum value - among the "simply parameterized models" - because all new charged fields just make it more likely for the Higgs to decay to the diphotons.

If there's no theorem about this yet, I think that someone may write it rather soon. It's a theorem that has loopholes, however.

reader Chris Walsh said...

It's very exciting that Stop quarks may be about to be observed! Also congratulations on your winnings!

Ummm...no. It's the same paper your original post is about! https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsSUS12009

reader Luboš Motl said...

Good, I probably looked at a paper with a similar ID. Yes, this is the same paper and Figure 5 is compatible with the SM. But it's not the only figure in that paper which is why you may want not to hide your head in the sand when it comes to the existence of Figures 3,4.