Ultra-peripheral collisions and diffraction (UD) analysis framework

The PWG-UD (Ultra-peripheral and Diffractive) working group focuses on the study of photon-induced and diffractive processes in heavy-ion and proton–proton collisions, as well as cosmic rays.

Get started

In the past, several hands-on sessions and tutorials have been organised within the PWG-UD to introduce the analysis framework. A list of the corresponding Indico events is provided below.

Past tutorials and hands-on sessions

• UD/O2 hands-on sessions from O2 Analysis Tutorial 4.0 (16 October 2024) - Introduction to the O² framework for UD analyses with practical examples. Includes introduction, Event selection for UPC, Data analysis with UD tables and MC simulation.
  • Example tasks:
  • UDTutorial_05.cxx – Two-pion analysis at midrapidity
  • UDTutorial_06.cxx – Forward muon analysis
  • UDTutorial_07.cxx – Event-by-event tree creation

• UD/O2 hands-on sessions from O2 Tutorial 3.0 (8 November 2023) — Overview of UD tables and accesing MC data Zoom recording part1, Zoom recording part2.

• UD/O2 hands-on sessions from O2 Tutorial 2.0 (27 April 2023) — Introduction to UD tables, task developement and hands-on sessions, Zoom recording part1, Zoom recording part2.

• O2 Analysis Tutorial (13–14 October 2022) — General introduction to the O2 analysis framework.

Contact

Mattermost channels: PWG-UD O2 analyses, PWG-UD general, O2AT-PWG-UD

Code

• The PWG-UD analysis code is located in the directory PWGUD
• Data model can be found here - UDTables.h
• Table produced by skimming and selecting event with double gap topology at midrapidity - DGCandProducer.cxx
• Class for event selection with double gap at midrapidity - DGSelector.h
• Table produced by skimming and selecting event with single gap topology at midrapidity - SGCandProducer.cxx
• Class for event selection with single topology at midrapidity - SGSelector.h
• Class for track selection with single gap topology at midrapidity - SGTrackSelector.h
• Table produced by skimming and selecting event with muon arm at forward rapidity - UPCCandidateProducer.cxx
• Utility and helper functions: UDHelpers.h
• Utility and helper functions: Tasks/CMakeLists.txt
• Quality assurance (QA) tasks: AQC

AliHyperloop

UD Hyperloop analyses with JIRA tickets

Framework structure

A schematic diagram of the typical workflow for a PWG-UD analysis is shown below.