# Probing three-nucleon-force effects via (p,2p) reactions

## TL;DR

This paper introduces a novel method using (p,2p) reactions to investigate three-nucleon-force effects, demonstrating significant impact on reaction cross sections and establishing a link to in-medium proton-proton interactions.

## Contribution

It proposes a new experimental approach with specific kinematic conditions to probe three-nucleon-force effects via (p,2p) reactions and analyzes these effects using chiral interactions.

## Key findings

- Chiral three-nucleon forces significantly alter the (p,2p) reaction peak heights.
- The method establishes a connection between (p,2p) cross sections and in-medium proton-proton cross sections.
- The approach offers a new way to study three-nucleon-force effects in nuclear reactions.

## Abstract

We propose to use proton knockout reactions (p,2p) from a deeply bound orbit as a new probe into three-nucleon-force (3NF) effects. The remarkable advantage of using (p,2p) reaction is that we can choose an appropriate kinematical condition to probe the 3NF effects. We analyze (p,2p) reactions on a 40Ca target within the framework of distorted-wave impulse approximation with a g-matrix interaction based on chiral two- and three-nucleon forces. The chiral 3NF effects significantly change the peak height of the triple differential cross section of (p,2p) reaction. We also clarify the correspondence between the (p,2p) cross sections and the in- medium pp cross sections.