Making The Most Of MET: Mass Reconstruction From Collimated Decays

par Chris Wymant

vendredi 11 oct. 2013, 14:00 → 15:00 Europe/Paris

Auditorium Marcel Vivargent (LAPP)

After a general introduction to the discovery of particles at colliders I will discuss the complications arising from invisible particles $\chi$. At hadron colliders such particles can be inferred only through observation of the transverse component of the vectorial sum of their momenta -- missing $E_T$ or MET -- preventing reconstruction of the masses of their mother particles. However in the context of boosted decays, collimation of the decay products gives information about the expected direction of invisible particles, allowing one to make the most of MET by decomposing it into the expected separate contributions. Each of these may be promoted to a full four-momentum approximating the associated $\chi$. Judiciously chosen pairings of the reconstructed $\chi$ with other visible objects in the event can lead to sharp mass peaks. I will explain the broad applicability of such an analysis to a host of different new physics signals, including more concretely four supersymmetric scenarios, mentioning briefly their respective theoretical motivations. Results will be shown for an illustrative case: the gauge-mediation decay of squarks to neutralinos to gravitinos.

Slides Wymant_Annecy_MakingMostMET.pdf