Next Generation Triggers (NGT) is a research and development effort within the CMS experiment at CERN, focused on rethinking the trigger system strategy for the Phase-2 upgrade of the HL-LHC and beyond.

The NGT project explores new paradigms for real-time data processing in high-energy physics, with the goal of enabling more powerful, flexible, and physics-driven trigger decisions.

A core component of this effort is the Real-time Reconstruction Revolution (R3) initiative.

R3 aims to bring offline-quality event reconstruction directly into the High-Level Trigger (HLT) filtering system, in real time.

Key ideas include:

• Buffering the entire HLT input stream
• Computing high-quality calibrations online during data taking
• Applying these calibrations before HLT reconstruction
• Producing compact, analysis-ready events with offline-level accuracy

This approach enables high-quality physics analysis directly from trigger-level outputs.

To demonstrate feasibility, NGT deployed a prototype system within the CMS data-acquisition infrastructure during LHC Run 3.

The prototype:

• Buffers approximately 1% of trigger data for several hours
• Computes precise calibrations during this buffering window
• Applies calibrations before HLT reconstruction
• Integrates seamlessly into the existing trigger workflow

The system is:

• Fully validated using standard CMS data-quality monitoring (DQM)
• Demonstrated to deliver calibration-aware, high-quality reconstruction
• Proven to operate directly within the trigger system

These results show that offline-level reconstruction quality in the trigger is both technically feasible and operationally robust.

NGT and R3 lay the groundwork for:

• More powerful trigger strategies at HL-LHC
• Increased physics reach under extreme pileup conditions
• A unified view of online and offline reconstruction

📌 This repository hosts code, studies, and documentation related to the NGT and R3 efforts.