A Review of Spin Determination at the LHC

TL;DR

This paper reviews methods for measuring the spin of new particles at the LHC, emphasizing angular correlation techniques in scenarios with long-lived neutral particles, and discusses experimental and computational challenges.

Contribution

It provides a comprehensive survey of spin measurement techniques focusing on angular correlations and discusses their application across various new physics models at the LHC.

Findings

Angular correlation variables can effectively determine particle spin.

Monte Carlo tools are essential for studying decay correlations.

Experimental challenges include detector resolution and background suppression.

Abstract

Spin measurements are crucial in distinguishing major scenarios of TeV scale new physics once it is discovered at the LHC. We give a brief survey of methods of measuring the spin of new physics particles at the LHC. We focus on the case in which a long lived massive neutral particle is produced at the end of every cascade decay and escape detection. This is the case for R-parity preserving supersymmetry, Little Higgs models with T-parity, extra-dimensional models with KK-parity, and a large class of similar models and scenarios. After briefly commenting on measuring spin by combining mass and rate information, we concentrate on direct measurement by observing angular correlations among decay products of the new physics particles. We survey a wide range of possible channels, discuss the construction of possible correlation variables, and outline experimental challenges. We also briefly survey the Monte-Carlo tools which are useful in studying such correlations.