Periodic Reporting for period 2 - HIGCC (Search for Higgs bosons decaying to charm quarks)
Reporting period: 2019-03-01 to 2020-08-31
Among these decay patterns is the decay into bottom quarks, which has been discovered, as expected, in the year 2018. A much bigger challenge, however, is the search for the decay into charm quarks. This is interesting because the small decay fraction into charm quarks of 2.9% makes it susceptible to BSM modifications, if they exist. A measurement of this charm decay fraction would either unravel new physics that has been sought for more than 60 years, or constrain BSM scenarios to enhance the understanding of the fundamental theory of matter.
However, the decay of the Higgs boson into charm quarks has been considered to be experimentally inaccessible at the LHC, because of the difficulties to distinguish charm quarks from other quarks. It is the goal of this project to overcome these experimental obstacles with new methods for the detection of charm quarks in the CMS detector. The new methods will be based on decay vertex reconstruction algorithms that make use of modern pattern recognition concepts. In combination with new techniques for data analysis and interpretation, this will facilitate the first observation of the Higgs to charm decay, and the measurement of its branching fraction, if it is anomalously enhanced through BSM contributions. With this strategy the first indication for physics beyond the standard model may be found. Even in the absence of a discovery, the project will be able to determine the world's best constraints on the Higgs to charm quark decay branching fraction.