I remember a funny shirt I once saw at a physics conference - it gave 10 tips on what to do when "everything else fails". Here is the list:

10. Subtract Infinity
9. Add heavy fermions
8. Set all fermion masses to zero
7. Invent another symmetry
6. Throw it on the lattice
5. Blame it on the Planck scale
4. Recall the success of the SM
3. Invoke the Anthropic Principle
2. Wave hands a lot, speak with a strong accent
1. Manipulate the data

Yesterday I worked from scratch at a problem which certainly others have already solved in the past. I have mixed feelings with such situations: on one side I hate to reinvent the wheel, especially if there is an easy way to access a good solution; on the other I love to invent new ones...


Anyway this time I have decided I will ask you for some help, as collectively we may have a better idea of the optimal solution to the specific problem I am trying to address. But before I explain the problem, let me give you some background on the general context.

Searches for new physics at the LHC

Bringing the concept of peer review to another dimension, I am offering you to read a review article I just wrote. You are invited to contribute to its review by suggesting improvements, corrections, changes or amendments to the text. I sort of need some scrutiny of this paper since it is not a report of CMS results -and thus I have not been forced by submit it for internal review to my collaboration.

I am quite happy to report today that the CMS experiment at the CERN Large Hadron Collider has just published a new search which fills a gap in studies of extended Higgs boson sectors. It is a search for the decay of the A boson into Zh pairs, where the Z in turn decays to an electron-positron or a muon-antimuon pair, and the h is assumed to be the 125 GeV Higgs and is sought for in its decay to b-quark pairs. 

If you are short of time, this is the bottomline: no A boson is found in Run 1 CMS data, and limits are set in the parameter space of the relevant theories. But if you have a bit more time to spend here, let's start with the beginning - What's the A boson, you might wonder for a start.