A new search for Higgs bosons in the context of two-higgs-doublet models has been carried out by the CMS collaboration at the CERN laboratory. This is not the first time that CMS searches for "the other four" Higgs bosons, which may arise if the standard model is just a tad less simple and elegant than it could be: recently, for instance, I have reported here of the search for the A bosonin final states including a "regular" higgs decay to b-quark pairs and a Z boson decay to electron-positron or muon pairs (and also reported the preliminary result earlier).

You may have heard that the Higgs boson was hypothesized as much as 50 years ago by Peter Higgs and independently by a few other theorists (among them notably Francois Englert, who shared the Nobel prize with Higgs two years ago) to provide the theory with the necessary "degrees of freedom" to allow for the physics of subatomic particles we experience. However, the addition of the Higgs field to the standard model Lagrangian (the function that describes forces and interactions) might have been done in a way that gives rise to five Higgs particles instead than one. Not two, or three, or four: five is the result of the "next least complicated" theory.

CMS has sought for heavy Higgs bosons decaying to a lighter A boson and a Z boson this time -something which is "orthogonal" to the previous search. The A boson in this case was sought in its decay to tau leptons (which are common in a wide area of parameter space) or b-quark pairs, and the Z always to electrons or muons.

The results return a negative outcome in the tau-tau-lepton-lepton final state, which is less sensitive, while the bbll final state seems to offer a hint of a possible signal, for two distinct combinations of H and A masses: (286,93) GeV and (662,575) GeV respectively. The first combination is a 2.6 sigma effect, and the second a 2.85 sigma one before accounting for the look-elsewhere effect (after which they decrease by one sigma each). 

Mind you, the mild excesses observed in the data are most likely the result of a statistical fluctuation; and yet, with just a few weeks to go before the LHC will start producing data at 60% higher energy than before, these might be things worth searching for as soon as possible when the new data will come in. Indeed, it would be really cool if we found these additional particles, as the "new physics" they would imply would pave the way to years of more detailed investigations; in addition, Supersymmetry fanatics would be deliriously happy, as SUSY requires the existence of at least five higgses.

Unfortunately the preliminary documentation of the CMS analysis do not provide a proper illustration of the two "excesses". The fact that the paper does not highlight them should be a word of caution: 2-sigma effects (not even such, in this case) are common in such searches. However, you could well argue that IF the LHC will discover some new physics in the new run, then it is quite likely that the relative signals have already been noticed, although not significant, in the old Run 1 data... Hence if you believe that two-higgs-doublet models are correct, you might want to bet that one of the above signals will turn out to be the first hint of new physics after all! 

I guess the above means that we have exciting times ahead, in all cases. We will go after the few 2- and 3-sigma discrepancies we have unearthed in Run 1 and kill them one by one... And we will find other suggestive excesses in the process.