results presented in Section \[sec:tbandsplash\] indicate that the HCAL system is capable of being synchronized to approximately 1–2 ns. Since sources of fake MET are generally uncorrelated with the collision event one can significantly suppress their contributions to MET using their reconstructed times. In the case of beam halo particles, although their arrival is correlated to the arrival of proton bunches in the beam, the exact arrival time to a given detector cell is generally distinguishable from the arrival time of particles produced in the interaction region.

Impact on out-of-time background {#sec:bkgdtiming}
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The strategy for using timing to reject backgrounds is implemented at the level of reconstructed cell measurements, rather than higher-level objects like hadronic jets or MET. It is expected that during data taking triggered events will contain collision data in around 1000 HCAL cells, over which additional out-of-time energy deposits may be superimposed. These out-of-time deposits can be individually removed from the calculation of MET rather than rejecting the entire event. The application of such a technique is appropriate for the analysis of prompt physics signals, while an analysis focused on long-lived particles might perform the reverse selection, preferring energy deposits that are out of time.

The 