Title :  “Improving Mass Measurements With Many-Body Phase Space"

Abstract: 

No conclusive evidence for physics beyond the Standard Model was discovered in run I of the LHC, leading us to suspect that even if new physics is discovered during run II, the number of signal events may be limited, making it crucial to optimize measurements for the case of low statistics. I will argue that phase space correlations between subsequent on-shell decays in a cascade contain additional information compared to commonly used kinematic variables, and that this can be used to significantly improve the outcome of mass measurements. The improvement is connected to features of the differential geometry of many-body phase space that are nontrivial and sometimes not well-known even to experts in this field. I will highlight a few such surprising features.