Speaker
Description
The CMS experiment implements a sophisticated two-level triggering system composed of Level-1, instrumented by custom-design hardware boards, and a software High-Level-Trigger. A new Level-1 trigger architecture with improved performance is now being used to maintain the thresholds that were used in LHC Run1 for the more challenging luminosity conditions experienced during Run2. The upgrades to the calorimetry trigger will be described along with performance data. The algorithms for the selection of final states with electrons and photons, both for precision measurements and for searches of new physics beyond the Standard Model, will be described.
Summary
The Compact Muon Solenoid (CMS) experiment implements a sophisticated
two-level triggering system composed of the Level-1, instrumented by
custom-design hardware boards, and a software High-Level-Trigger.
During Run 2, the LHC has increased its centre-of-mass energy to 13 TeV
and will progressively reach an instantaneous luminosity of
$2\times~10^{34}~\text{cm}^{-2}\text{s}^{-1}$.
In order to guarantee a successful and ambitious physics programme the
CMS Trigger and Data acquisition (DAQ) system has been upgraded.
A new Level-1 trigger architecture with improved performance is now
being used and a novel concept for the L1 calorimeter trigger is
introduced: the Time Multiplexed Trigger (TMT). In this design, which
is similar to the CMS DAQ or HLT architecture, nine main processors receive
each all of the calorimeter data from an entire event provided by 18
preprocessors. The advantage of the TMT architecture is that a global
view and full granularity of the calorimeters can be exploited by
sophisticated algorithms. The goal is to maintain the current thresholds
for calorimeter objects and improve the triggering efficiency.
The introduction of new triggers based on the combination of calorimeter
objects is also foreseen.
The performance of these algorithms will be presented, both in terms of
efficiency and rate reduction using the proton collision data collected
in 2016. The challenging aspect of the pile-up mitigation will be
addressed along with the rejection of anomalous signals (spikes) in the
APDs.
The impact of the improved selections on benchmark physics with
electrons and photons in the final states will be discussed using as
examples precision measurements of the Higgs boson properties and
searches for new physics beyond the Standard Model.
