Probing subatomic world secrets
The search for the Higgs boson and the estimation of its mass needed precise extraction of the Higgs boson's signal from background processes. The main objective of the 'Precision study of W bosons pair production in association with jets at high energy colliders' (SAMURAI-APPS) fellowship was to provide largely automated tools for this purpose. In particular, the SAMURAI-APPS team developed tools for high order corrections of hadron-hadron collisions. The software package GOSAM was developed to support the automated calculation of the scattering cross-section, describing the probability of interaction between particles. The coupling between interacting particles was visualised using Feynman diagrams. High order corrections were represented in diagrams with loops. GOSAM was used to calculate corrections within both quantum chromodynamics (QCD) and electroweak theory. QCD is the theory of the strong interactions between elementary particles which along with the electro-weak interactions compose the Standard Model. The user only needs to specify the details of the process to be analysed, and launch the generation of the source code and its compilation. Depending on the setup for the given process, scattering amplitudes can be deduced with different techniques. GOSAM offers the option of choosing the best approach in terms of speed and numerical stability. On 4 July 2012, the observation of a Higgs boson with a mass around 125 GeV was announced at the European Organization for Nuclear Research (CERN). This discovery implied a great success of the Standard Model with measurements of the Higgs boson properties being consistent with the theoretical predictions. Although the Standard Model accurately describes phenomena within its domain, some pieces of the jigsaw puzzle are still missing. Use of the SAMURAI-APPS tools with more LHC experiments could change all this. Detailed measurements of all the decay branching of the Higgs particle as well as of other new particles are expected to reveal unknown facets of the subatomic world.
Keywords
Standard Model, Large Hadron Collider, Higgs boson, GOSAM, Feynman, quantum chromodynamics, electroweak, elementary particles, subatomic
