Flavour Changing Neutral Currents in top quark decays

This work contains an estimation of the observability
of the Flavour Changing Neutral Currents (FCNC) in
top decays with the CMS experiment at the future
Large Hadron Collider (LHC).
Since expected branching ratios for top FCNC in the
Standard Model are eagerly low, any experimental
evidence for a top quark FCNC interaction would
signal the existence of physics beyond the Standard
Model. A wide variety of Standard Model processes
have been considered into background, and selection
is optimized in order to maximize the significance in
the signal region. A full set of systematic effects,
originating from detector or theoretical
uncertainties, are added to the simulation and their
impact on the analysis is established. Results are
presented for several background levels and different
experimental conditions, then extrapolated to the
highest attainable LHC luminosities. An improvement
of two orders of magnitude in sensitivity to FCNC
branching ratio is obtained, allowing to shed light
on different new physics scenarios.

Autorentext

Leonardo Benucci, (Florence, 1975). Intrigued since childhood byNature's mysteries, after graduating he worked in Marseille andgot a PhD at Pisa University. Now in Antwerp, his passion forparticle physics led him to be involved in the construction ofLarge Hadron Collider (accelerator at CERN, Geneva) anddeveloping new tools for discoveries.

Klappentext

This work contains an estimation of the observabilityof the Flavour Changing Neutral Currents (FCNC) intop decays with the CMS experiment at the futureLarge Hadron Collider (LHC).Since expected branching ratios for top FCNC in theStandard Model are eagerly low, any experimentalevidence for a top quark FCNC interaction wouldsignal the existence of physics beyond the StandardModel. A wide variety of Standard Model processeshave been considered into background, and selectionis optimized in order to maximize the significance inthe signal region. A full set of systematic effects,originating from detector or theoreticaluncertainties, are added to the simulation and theirimpact on the analysis is established. Results arepresented for several background levels and differentexperimental conditions, then extrapolated to thehighest attainable LHC luminosities. An improvementof two orders of magnitude in sensitivity to FCNCbranching ratio is obtained, allowing to shed lighton different new physics scenarios.