Evidence for the direct decay of the 125 GeV Higgs boson to fermions

Question

Referee this paper: arXiv:1401.6527 by CMS Collaboration

Please use comments to point to previous work in this direction, and reviews to referee the accuracy of the paper. Feel free to edit this submission to summarise the paper (just click on edit, your summary will then appear under the horizontal line)

(Is this your paper?)

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Answer 1

It is a part of the intensive investigations made to confirm that the new discovered boson around 125 GeV, which was observed coupling to bosons, is really the Brout-Engels-Higgs boson of the Standard Model.

This very technical short report focuses of the study of the theoretical decay BEH boson -> bottom quarks and T leptons particle/antiparticle pairs. To hide the QCD direct production of bottom/anti quark pairs noise, only decays associated to a W or a Z boson production are selected. Results are consistent with the Standard Model prediction of a Yukawa structure, where coupling are proportional to the fermions masses. Assuming that the BEH mechanism is produced as expected in the SM, this leads to the conclusion that the 125 GeV BEH boson, previously indentified to couple to bosons, couples also to down-type fermions. This internal consistency of the standard model does not invalidate all the fermions mass origin alternative theories, but gives strong indications on the pertinency of the new boson existence and unicity.

The student in experimental physics can find here inspiration for a lot of numerical and technical exercises, fe on the data discrimination and the significance notion and evaluation. Supplemental data are available in other publications. It is also a model of rigor for any experiment that he will have to carry out later.

Comments

Isn't "This internal consistency of the standard model..." due to many fitting parameters of SM?

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@VladimirKalitvianski: general consistency of the SM is out of topic :) I was meaning internal consistency of the BEH mechanism in the SM. The new boson seems certainly to be the SM BEH boson. While it is a minimalist conclusion, they found the predicted decay associated with W and Z, and the resulting related BEH boson energy is in the same bounds than the one found to couple with bosons.