# Single spin asymmetries in forward p-p/A collisions revisited: the role of color entanglement

## TL;DR

This paper investigates the impact of color entanglement on single spin asymmetries in forward proton-proton and proton-nucleus collisions, revealing that certain contributions vanish while others remain unaffected, providing insights into the sign mismatch problem.

## Contribution

It demonstrates that color entanglement causes the Sivers contribution to SSA to vanish, offering a natural explanation for the sign mismatch issue in spin asymmetry measurements.

## Key findings

- Sivers contribution to SSA drops out due to color entanglement
- Fragmentation contribution remains unaffected by color entanglement
- Provides a natural solution to the sign mismatch problem

## Abstract

We calculate the single transverse spin asymmetries(SSA) for forward inclusive particle production in pp and pA collisions using a hybrid approach. It is shown that the Sivers type contribution to the SSA drops out due to color entanglement effect, whereas the fragmentation contribution to the spin asymmetry is not affected by color entanglement effect. This finding offers a natural solution for the sign mismatch problem.