# Mini-AOD: A New Analysis Data Format for CMS

## TL;DR

The paper introduces Mini-AOD, a compact data format for CMS analysis that reduces data size by about 90%, enabling faster and more efficient physics analyses with sufficient information for most studies.

## Contribution

It presents the design, implementation, and deployment experience of the Mini-AOD format, a significantly smaller data format for CMS analysis, optimized for efficiency and ease of use.

## Key findings

- Mini-AOD reduces data size to about 10% of previous formats.
- It maintains 80% of analysis capabilities with simplified data.
- Deployment has improved analysis efficiency and resource management.

## Abstract

The CMS experiment has developed a new analysis object format ("Mini-AOD") targeting approximately 10% of the size of the Run 1 AOD format. The motivation for the Mini-AOD format is to have a small and quickly derived data format from which the majority of CMS analysis users can start their analysis work. This format is targeted at having sufficient information to serve about 80% of CMS analysis, while dramatically simplifying the disk and I/O resources needed for analysis. Such large reductions were achieved using a number of techniques, including defining light-weight physics-object candidate representations, increasing transverse momentum thresholds for storing physics-object candidates, and reduced numerical precision when it is not required at the analysis level. In this contribution we discuss the critical components of the Mini-AOD format, our experience with its deployment and the planned physics analysis flow for Run 2 based on the Mini-AOD.