Abstract

The Compact Muon Solenoid (CMS) experiment has implemented a sophisticated two-level online selection system that achieves a rejection factor of nearly 105. During Run II, the LHC will increase its centre-of-mass energy up to 13 TeV and progressively reach an instantaneous luminosity of 2 × 1034 cm−2 s−1. In order to guarantee a successful and ambitious physics programme under this intense environment, the CMS Trigger and Data acquisition (DAQ) system has been upgraded. A novel concept for the L1 calorimeter trigger is introduced: the Time Multiplexed Trigger (TMT) . In this design, nine main processors receive each all of the calorimeter data from an entire event provided by 18 preprocessors. This design is not different from that of the CMS DAQ and HLT systems. 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 performance for their selection. The performance of these algorithms will be demonstrated, both in terms of efficiency and rate reduction. The callenging aspects of the pile-up mitigation and firmware design will be presented.

Highlights

  • The Compact Muon Solenoid (CMS) experiment has implemented a sophisticated two-level online selection system that achieves a rejection factor of nearly 10e5

  • The advantage of the Time Multiplexed Trigger (TMT) architecture is that a global view and full granularity of the calorimeters can be exploited by sophisticated algorithms

  • As the LHC restarts and operates at higher luminosity, the current CMS trigger system will not be capable of maintaining the thresholds required for the CMS physics programme

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Summary

A BSTRACT

The Compact Muon Solenoid (CMS) experiment has implemented a sophisticated two-level online selection system that achieves a rejection factor of nearly 105. A novel concept for the L1 calorimeter trigger is introduced: the Time Multiplexed Trigger (TMT). In this design, nine main receive each all of the calorimeter data from an entire event provided by 18 preprocessors. Nine main receive each all of the calorimeter data from an entire event provided by 18 preprocessors This design is not different from that of the CMS DAQ and HLT systems. The goal is to maintain the current thresholds for calorimeter objects and improve the performance for their selection. The performance of these algorithms will be demonstrated, both in terms of efficiency and rate reduction.

Upgrade of the Level-1 trigger system for Run II
Improved selection algorithms at Level-1
Electron and photon trigger algorithm
Selecting tau leptons
Jet and energy sums algorithms and their performance
Firmware implementation and first commissioning results
Findings
Conclusion
Full Text
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