Wednesday, October 21, 2015 ... Deutsch/Español/Related posts from blogosphere

Egyptians, Romans demand a new Higgs at \(145\GeV\)

Will Joan of Arc and William Tell surrender?

If you look at my long list of bumps and excesses that are waiting to be confirmed or (more likely) deflated by the continuing LHC experiments, you will notice one category of tantalizing hints that is larger than others: possible new Higgs bosons.

In 1988 or so, I had to attend rock'n'roll classes where I had to pretend to learn how to dance it and this piece released in 1986 was by far the most frequently played song over there. Not only because my talent for similar things is close to zero, it was so humiliating.

The Standard Model predicts one physical Higgs particle species, the boson whose mass has to be \(125\GeV\) to match the recent discoveries. But alternative theories with a richer field content predict new Higgs bosons. The minimal supersymmetric models predict that the God particle has five faces and there exist new sources of the Higgses, e.g. in the "next to minimal" theories.

Aside from the well-known \(125\GeV\) particle, my list of possible other Higgs bosons includes other CP-even Higgses at \(98\GeV\) (LEP), \(136.5\GeV\), and \(144.5\GeV\), one at \(320\GeV\) and/or \(325\GeV\), perhaps new particles at \(2,3,5\TeV\), and a CP-odd Higgs boson at \(560\GeV\).

The \(145\GeV\) Higgs boson already had some evidence in Summer 2011. A combination of 4 LHC and Fermilab experiments suggested a more than 3-sigma combined excess centered around \(144\GeV\). If you like that possibility of a new Higgs boson, you should walk like an Egyptian.

There is a short physics.pop-ph paper by Dr Cleopatra Tutankhamun and Dr Cicero Caligula

Can we have another light (\(\sim 145\GeV\)) Higgs boson?
that tries to summarize the evidence supporting such a new particle. (Yes, the first author works in Cairo – it is sort of incredible to imagine that it's the same place that otherwise produces "gems" such as the Muslim Brotherhood.) It could explain various anomalies. There were excesses at CMS in 2012 – comparable to 3 sigma themselves. This sounds rather remarkable because these excesses would be on top of the excesses I mentioned in 2011.

And in fact, you could also argue that the Higgs-like hints at the Fermilab in early 2011, for a new particle around \(140\GeV\) in the \(\ell\nu q\bar q\) channel, were another independent piece of evidence that something like that occurs in that mass range.

I had to include a Roman song analogous to the song by the Bangles at the top. My pick was "The Colosseum" by Ms Marika Gombitová (CS/SK). Incidentally, music lovers simply have to download MusiXmatch for their devices. It identifies a song but unlike Shazam or SoundHound, it shows you the verses of lyrics that are being sung at this very second (and the next one, in smaller fonts). So you may sing it! It works for this Colosseum song, too. BTW after a car crash in 1980, Gombitová was stuck on a wheelchair. Among her 200+ songs, The Confession [better sound] is probably the most touching one.

Note that in Summer 2011, we were living the short epoch in which I believed that the most likely mass of the "main" or "only" soon-to-be-discovered Higgs boson was \(115\GeV\). In December 2011, it became almost certain that the actual mass was \(125\GeV\).

The authors are proposing an explanation of this second Higgs boson using the BLSSM, a nearly minimal supersymmetric standard model with some extra \(U(1)_{B-L}\) gauge group. I think that the probability that this group exists in Nature – and at reasonably low energies – has increased because this group is tied to the \(SO(10)\) and higher grand unification whose probability has also increased due to the hints suggesting the left-right-symmetric models and new \(W'\)-bosons and similar stuff.

We haven't heard anything interesting about the anomalies seen at the LHC for 1 or 2 months. But it can be the silence before a storm because it was exactly the period when the LHC was finally patiently collecting lots of data at \(13\TeV\). Right now, both ATLAS and CMS have accumulated something like 2.5 inverse femtobarns at this higher energy, about 1/10 of what was totally recorded at \(8\TeV\) in 2012.

This is already a substantial amount of data. For example, because the current run is much more sensitive to very heavy new particles, most objects safely above \(1\TeV\) of mass should already be more visible (lead to more statistically significant excesses) in the already available 2015 data than the old 2012 data! This includes the possible events at \(2,3,5\TeV\).

Because of some recent excesses, it seems totally plausible to me that the first kind of new physics that the LHC may discover may point to new gauge groups compatible with the grand unification. It would be a real revolution. From some (but not all) perspectives, it would be a deeper revolution than the (later) discovery of SUSY – for example, it could allow us to extrapolate and determine some physics at much higher (GUT) scales.

Add to Digg this Add to reddit

snail feedback (0) :

(function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){ (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o), m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m) })(window,document,'script','//','ga'); ga('create', 'UA-1828728-1', 'auto'); ga('send', 'pageview');