Tuesday, September 30, 2014

Glimpsed second Higgs at \(137\GeV\) OK with BLSSM, not MSSM

Fifteen months ago, I discussed a very interesting paper by CMS that has seen a 2.73-sigma or 2.93-sigma (depending on details) excess suggesting the existence of a second CP-even neutral Higgs boson at mass \(m_{h'}=136.5\GeV\).

Three months later, I mentioned some weak dilepton evidence in favor of this new particle. Today, W. Abdallah, S. Khalil, and S. Moretti released a hep-ph preprint that tests the incorporation of this hypothetical second Higgs boson into supersymmetric models:
Double Higgs peak in the minimal SUSY \(B-L\) model
It may be the most interesting paper on the arXiv today.

They perform some detailed analysis and conclude that the Minimal Supersymmetric Standard Model, or MSSM, isn't compatible with all these data. However, one extremely simple and well-motivated extension of the MSSM, the BLSSM – the \(B-L\) Supersymmetric Standard Model – seems to agree perfectly.

It is a model that (or to say the least, whose spectrum) you may consider to be a low-energy limit of the \(SO(10)\) grand unified theories (GUT) – which seem more attractive and supported by the data than the minimal \(SU(5)\) GUTs, anyway, e.g. because of suggestive neutrino patterns, love of David Gross :-), a simple incorporation to heterotic string theory, and other reasons.

The BLSSM has an extra right-handed neutrino supermultiplet in each generation of fermions; recall that in \(SO(10)\) GUTs, they are coming naturally from the \({\bf 16}\) spinorial representation responsible for all the quarks and leptons, including the right-handed neutrinos. A seesaw mechanism may be naturally combined with this spectrum to produce the observed small neutrino masses – something that is less natural or at least less explicit in the MSSM.

There's also the \(U(1)_{B-L}\) gauge field with its gauge bosons and gauginos. Recall that if you embed \(U(5)=U(1)\times SU(5)\) to \(SO(10)\), this difference of the baryon and lepton numbers arises as the extra \(U(1)\).

Finally, the BLSSM contains some extra neutral Higgs supermultiplet. It also increases the natural expected masses of the Higgs bosons relatively to the MSSM which reduces the "small amount of fine-tuning" or "small hierarchy problem" that is apparently present according to the MSSM.

ATLAS hasn't told us whether it sees the resonance near \(137\GeV\) as well. It could be very interesting because such a newly discovered particle would be not only a strong piece of evidence in favor of SUSY but also in favor of grand unification – and in fact, a prettier, non-minimal version of it!

And imagine the excitement that the second \(137\GeV\) Higgs boson would bring to all the numerologists obsessed with the fine-structure constant.

I am promising you absolutely nothing but stay tuned. ;-)

Director Rolf Heuer celebrates CERN's 60th birthday with a gesture he learned from his granddad. Congratulations!

P.S.: I made a search for papers and talks that would mention a \(137\GeV\) Higgs boson. Remarkably, ATLAS has seen a small excess in the diphoton channel around \(137\GeV\) as well, see e.g. pages 10 and 16 of these slides. The \(137\GeV\) Higgs boson appears six times in these older slides, too. See also this August 2012 paper on these two bosons. In 2011, \(137\GeV\) was also the upper bound on the Higgs mass imposed by the Tevatron but as far as I see, there was no bump over there – just a monotonic curve for the probability that crossed a threshold.


  1. Mohapatra provided a history of B-L yesterday: http://arxiv.org/abs/1409.7557

  2. alejandro riveroSep 30, 2014, 4:42:00 PM

    Kaluza-Klein-wise, B-L or any extra U(1) increases the minimum of extra dimensions to 8, which on one hand is very bad, as we go beyond D=11 and then beyond the max allowed dimension of supergravity, and on the other hand it is interesting because the issues with fermions are always less problematic in even dimensions.

    Also, once the cat is out, the next temptation is Pati-Salam "SU(4)" lepton colour unification. A lepton-colour group is a natural place to look for a B-L charge, as we have that leptons are L=1 and coloured particles are B=1/3.

    A nice manifold in 8 dimensions is the product of five-sphere and three-sphere, as it has an isometry group SO(6)xSO(4) and thus SU(4)xSU(2)xSU(2), which is slightly greater than the SU(3)xU(1)xSU(2)xU(1) that we need for just a B-L addition to the standard model. Of course, we can also proceed by simply adding a circle S1 to some 7-dimensional manifold with the adequate symmetry.

  3. Well, since I'm not a particle physicist, I'll just come out and say it: I'm rooting for this second Higgs if it implies super-symmetry within near reach of LHC or its successor. Unlike real physicists apparently, I think finding super-symmetry will be much more fun than not finding it.

  4. There is no hierarchy problem or no naturalism problem. The Multiverse may just be utterly infinite and probabilistic. You may have to come to terms with this and no doubt it will be like people's refusal to accept QM.

  5. Xi JingPing is an LQG supporter.

  6. Hm, is it not a bit early to throw in the towel on explaining things from understanding the nature of string theory better and deeper for example ?

  7. Rivers are a problem across the globe, re Benny Hill,
    A politician said he’d take us to the Alster Lake,
    The dummkopf took us to the river Elbe by mistake,
    Of course a girl should never let a politician help her,
    ‘Cause politicians do not know their Alster from their Elbe.

    I'd furnish a video link, but it might be distracting.

  8. It is in keeping with their history and culture. The strongest motivation for breaking with tradition would come from seeing a different system being more successful, but the post-Soviet debacle of the 1990's made them even more leery of chaos, the US chronic inability to make a dent in its insane debt takes care of that example, and China's growth rates have outpaced those of democratic India. I am not sure how they see the EU, but it's not a single state anyway.

    They may liberalize eventually, but who knows when, and if.

  9. I'm in China and I use VPN. Many of my students know about VPN and how to use proxies. Unfortunately most of the students are as dumb as dogshit and think having an IQ of 90 is good. Most do hate the government but love China. About 10% want to join the party, not because of belief in the system, but because they think they can gain an advantage. The Hong Kong thing is more about sticking your finger in the eye of authority. They are like a dog chasing a car. Once they catch it , they don't know what do with it.

  10. Hong Kong is very likeable city. Clean, safe and efficient, yet at every corner you can get a great noodle soup made in a small mom and pop restaurant. It is one of the cities where you may feel, if I can get a good job and decent salary, I would want to live here, at least for a while. In a sense they are all elite, while the rest of the mainland are dumb peasantry from Middle Ages or whatever they had in China in those days. Given that, I can understand they may feel unhappy with their future lifestyle being decided by some crude party peasantry that was munching hog intestines before they got promoted.

  11. What an interesting insight! From 1982 to 1988 I made dozens of trips to Hong Kong and Taipei, so here are things that made a huge impression on me.

    When the PRC (People's Republic of China) announced their successful tests of nuclear weapons in the 1980s my colleagues who ran our Taipei factories were delighted. This puzzled me as I thought they should fear nuclear weapons in the hands of the PRC. Instead, my Taiwanese colleagues were proud of Chinese achievements in nuclear technology, confident that these weapons would never be used against them.

    My sister lived in Hong Kong for many years and I made many visits so I know the enclave never experienced Democracy. The Legislative Council members were appointed by the British. Since 1997, the ruling body is still in the hands of appointees but now the PRC does the appointing.

    While there was a Democracy movement as the British rule drew to a close, it has gathered strength since the Brits departed. While I support the idea of elected rather than appointed members of the Legislative Council in principal, it should be remembered that an appointed body can work well if corruption is held in check. An elected body can work badly if corruption is rewarded (e.g. Mexico).

  12. Mainland China is not much different to Hong Kong. Mainlanders are not peasantry living in the middle ages. I have lived in mainland China for over 10 years and have visited over 50 cities. I have enjoyed the mom dad corner places over this time. It's not pristine, as westerners may like, but it's quite cool. No food poisoning from these places. People are very friendly to foreigners. I have been to many countries around the world and people treat me nicely. Never an issue. My cardinal rule is to deal with people politely and with respect. Works for me.

  13. Thanks, Camel, for this complementary yet compatible view! Sometimes it's interesting where the confidence in the communist countrymates comes from. Many socialist regimes - including Mao's China - have shown rather clearly that murdering lots of countrymates doesn't seem to be hard for them.

  14. Hog intestines are delicious. If that is your taste.

  15. Tony.
    I have heard an expression.
    Put your brain into gear before you put your jaw in motion.
    'You know nothing Jon Snow.'

  16. I feel as if it's absurd for people in Hong Kong not to expect their important electoral processes to be tampered with, either secretly or blatantly, by the political elite of mainland China. It's like expecting an intelligent man with a strange growth on his chest not to monitor it and, in certain cases, have it cut out.

  17. And the electoral processes in the west are not tampered with? We vote for the person appointed in our electorate by the party. God only knows why that particular idiot is appointed to represent me. I guess I have to trust the party. Good citizen that I am.

  18. I'm a little surprised that you think that Chinese People's thinking is the same as Chinese government thinking. Chinese people are under the yoke of the government. Confucianism stops the people from rebelling.

  19. OK, I don't have enough data but claiming that religion is what decides about the survival of the communist political system sounds contrived to me.

    Moreover, quite generally, I don't really believe that regimes may survive without an enthusiastic support of a part of the nation that is at least as large as 15-20%.

  20. 'And the electoral processes in the west are not tampered with?'

    When did I ever say that I believe or disbelieve this? I was commenting on mainland China and Hong Kong—nothing else. But when it comes to many a country's important political processes, I'm pessimistic (at times too pessimistic) and am reluctant to think them entirely fair. The novelist Gore Vidal once wrote, 'Don't ever make the mistake with people like me thinking we are looking for heroes. There aren't any and if there were, they would be killed immediately. I'm never surprised by bad behaviour. I expect it.' I think that's wise.

  21. I'm envious of your ten years there. If you don't mind my asking, why have you been there for ten years? Do you plan to spend your life there?

  22. What most people don't realise, including western leaders, is that the Chinese government is not in charge of China. It's the PLA. The PLA has tasked the government of China(whatever form that takes) to look after the welfare of the people. The PLA marched into Tibet and told the government there to get their act together and get rid of the feudal system. The PLA is for the people. They are revered by the common folk. Young girls go wet at the thought of being associated with a soldier. These young men put their lives on the line in natural disasters(no bullshit). There is a special day in China to honour some young soldier who died at an early age(run over by a truck). Apparently he used to help old people across the street.
    So some 5 star American general is sitting across the table from some Chinese general and doesn't realise that he is out of his depth.
    That chinese fucker can blow his brains out with impunity and doesn't have to answer to the government..

  23. I didn't mean it as some attack on you. You only mentioned China in your comment. I was merely expanding it to include the rest of the world. I was , in some oblique way, agreeing with you.

  24. confucianism is a philosophy. Its actually not a religion as such, although people may follow it religiously. It was integrated into common thinking for several thousand years. Useful for the emperors.
    Much like judeo-christian thinking was incorporated into kingship in the west a long time ago.
    The communists incorporated this into their philosophy. It was part of chinese psyche. Confucianism is deeply ingrained. I had no idea what 'filial piety' meant when I heard it from so many students. I had to look it up on google.
    Unfortunately you are very logical. None of what I am saying makes any sense to you. It took me a lot of fucking time to get my head around it too.
    It makes some sense to me now. Perhaps I am insane.

  25. I would love to. Unfortunately the government rules don't allow me to stay here indefinitely. I was actually born here but spent most of my life in Australia. Being born here doesn't give you any rights to residency. I have to have yellow skin and slanty eyes to be allowed to stay. I'm just being blunt and not racist.. My work visa is issued year by year. Unfortunately/fortunately I am 65 going on 66. The government only allows 'Foreign experts' to age 60. They can extend it to 65 in exceptional circumstances.
    My time is up. Going back to Australia next year. Love it here but I guess it's time to move on.

  26. I only planned for 1 year, But fell in love with the place. I also became an upper middle class citizen. Comfortable life, even though money is not the same as western money. I don't care about the money, its about the lifestyle. It was cool here and I decided to stay. Alternatives were not attractive. I am a person with a flexible nature so I had no problem fitting in.

  27. But does SUSY play any role in this paper? A second higgs was also predicted in fig. 1a here http://arxiv.org/pdf/1306.2329v1.pdf

  28. It isn't really about impossibility to map.
    I spent quite some time in China (much less than 10 years :)) and was always interested by languages in general so that I asked the Chinese questions about the Chinese language all the time.
    Actually I find that Czech is probably best suited to transcribe Chinese sounds because Czech has the interesting property that there is (almost) an isomorphism between a sound and a single letter.
    For instance the city Xian is pronounced (in Czech transcription) šijan.
    The transcription of the noun German would be dejži (which sounds surprisingly quite like Deutsch)
    And of course the well known example of tea which in Chinese is simply pronounced čaj ... :)
    So the problem is actually in the multiplicity of different transcriptions in different languages which use different conventions each.
    In my experience the set of Chinese non tonal sounds is strictly contained in the set of Czech sounds from what follows that a Czech transcription is (probably) the best as far as sound production is concerned. Russian would not be bad either but they have no h sound which is needed for chinese.
    Of course nothing of the above applies to wovels because Chinese uses tones (4 of them or 5 if one counts the zero tone). As the meaning of a word (like Ma) changes when the tone changes and our ears are not trained to hear tones let alone to produce them correctly, any transcription of a tone is necessarily artificial unless we use another of the not so common tonal languages like vietnamese, swahili or zoulou.
    None of the indoeuropean languages are tonal so that the root indoeuropean , mother of us all, was probably not tonal either.

  29. Dear Tom, the Czech spelling is phonetic which is the best way to write down any compatible sounds. No doubts about it. We're not the only ones who have it in this way, more or less. I think that Slovenian or some other Yugoslavs and others have the same.

    But the point of mine was that some sounds in Chinese are simply not mapped to any Czech sounds - just like the English "th" is not. The "X" is close to "sh" but it isn't quite the same thing. Also, their "L" is close to our "L" but it is a hybrid including some "R", too. something in between "L" and "R" said in a sloppy way.

    And the vowels are mess. Much like the English ones, they're non-uniform sounds that are evolving in time - like English likes to say "Ey" "Oy" "Oh" and so on all the time, Chinese does it as well, but some of these gradual transformations are melted along with consonants etc., so the clearcut Czech phonetic transcription doesn't quite help to faithfully capture the sounds. Am I wrong?

  30. The problem is that chinese is not phonetic as westerners understand it. We are dead keen on getting the pronunciation right. The chinese are about the tone. That being said, my students have sometimes argued amongst each other about the tone in their names. Telling each other that they are pronouncing their own names incorrectly. Stupid fucking language. That's why they are learning english. My wife has tried learning it. I couldn't be bothered. I get away with 'point and grunt'. I think it's easier to teach 1.3 billion people to speak english. Fuck trying to learn a language that even the chinese have difficulty with. I have asked some chinese students about some chinese pronunciation or some meaning. Quite a few said their chinese is poor and I should ask someone else. The expression on my face would have been precious.

  31. Believe me, if any asians, who survived far more tricky mathematics test than other region in this planet, appears dumb to you, the reason always is that they don't give a shit on you or your business. So maybe you should make yourself or your business not that dogshit, then they will give their smart side.

  32. The basic framework sounds sensible - just a correction. They should be learning Czech, not English. ;-)

  33. I have visited all the places where Chinese conglomerate, like mainland(all major cities plus terracotta soldiers), Taiwan, Hong Kong/Macau, Singapore and Malaysia. I had a vacation apartment in Malaysia, I was going there 2-3 times per year. On the main Malaysian island 60% are Chinese( west cost) and they are the one who actually built the economy mostly. Each of these groups have a slightly different characteristics, but yet have the Chinese character of course. Every traveler knows that he can get information about local conditions by chating with taxi drivers. In Hong Kong I got the impression they don't like the mainland people, they see them as basically uncultured.

    Mainland is as modern as any other advanced country, even I was surprised to see how even the smaller towns where very nicely maintained. However, I do agree with that taxi driver somewhat. Standing in the line to board the bullet train to Shanghai, people were literally climbing over our bags and bodies to get ahead.

    I also have a perspective which might be useful to understand the differences between these groups. Being ethnically Persian but living in an Arab country(ancestors migrated 150 years ago), I have a very confused feeling towards both. I act like Arabs with heavy heart, but my connection with Persian character is not that great, I don't understand them or like them. But I have affinity for their music, art and history.

  34. dear Lubos
    Is it possible that this particle is just another particle, can it be tested for stability, Thanks,

  35. Dear Qsa, if this is anything else than a random fluke that will go away, it is certainly another particle - just like there is the first Higgs, there is the second Higgs, and they only differ in some detailed properties. And this particle, if it exists at all, is certainly unstable and very short-lived, otherwise we would see it everywhere and all the time.

  36. Aha! 137 GeV:) That was my prediction in a 2011 TRF post with a poll, I seem to remember.

  37. LOL, I had your nickname partly in mind when I mentioned the numerologists. ;-)

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  39. numerologist?:) It's also my birthday!