Juri Fiaschi
Speaker affiliation: 
University of Southampton
Thursday, March 19, 2015 - 13:00
Building 46, seminar room (5th floor)
Z’ physics: new bounds, searches and the role of AFB as a discovery tool at the LHC
The role of the Forward-Backward Asymmetry (AFB) in Z physics is commonly associated to the interpretation of experimental data after a possible discovery. This observable is indeed used to distinguish between different models predicting at least one extra heavy spin-1 Z -boson. We examine the role of AFB in searching for new heavy Z -bosons and show that it might be powerful at the CERN Large Hadron Collider (LHC). We analyse two different scenarios: narrow width Z -bosons and wide Z -bosons. We find that, in the first case, the significance of the AFB search can be comparable with the bump search usually adopted by the experimental collaborations. The advantage of using AFB would be minimizing systematical errors, being AFB a ratio of (differential) cross sections. In the second case, the AFB search can win over the bump search in terms of event shape. The structure of the AFB distribution as a function of the invariant mass of the reconstructed Z -boson could nail down the new broad resonance much better than the event counting strategy usually adopted in such cases.