computed as the negative of the vector sum of the of all PF candidates reconstructed in an event, and its magnitude is used in the search as a discriminator between signal and SM background. Events selected for the search are required to pass filters [@Sirunyan:2019kia] designed to remove detector- and beam-related backgrounds, and must have at least one reconstructed vertex. Usually, more than one such vertex is reconstructed because of pileup, , multiple proton-proton ($\Pp\Pp$) collisions within the same or neighboring bunch crossings. The mean number of interactions per bunch crossing was 27 in 2016, and increased to 37 in 2017, assuming a total inelastic $\Pp\Pp$ cross section of 80. The reconstructed vertex with the largest value in summed object $\pt^2$ is selected to be the primary $\Pp\Pp$ interaction vertex (PV). These objects are defined by tracks associated with a given vertex that are clustered using a jet finding algorithm [@Cacciari:2008gp; @Cacciari:2011ma], and a more restricted form of the vector missing transverse momentum that is calculated from these track-based jets.

Charged particles that originate from the PV, photons, and neutral hadrons are clustered into jets using the anti-algorithm [@Cacciari:2008gp] with a distance parameter of 0.4, as implemented in the package 