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Updated: May 18, 2026

Coulomb Explosion Imaging as a Tool to Distinguish Between Stereoisomers
Published on: August 18, 2017
First measurement of chiral dynamics in π- γ → π- π- π+
C Adolph1, M G Alekseev, V Yu Alexakhin
1Universität Erlangen-Nürnberg, Physikalisches Institut, 91054 Erlangen, Germany.
The COMPASS Collaboration studied the three-pion production reaction using 190 GeV pions. Results agree with chiral perturbation theory predictions for this fundamental particle physics process.
Area of Science:
- Particle Physics
- Nuclear Physics
- Quantum Chromodynamics
Background:
- The COMPASS experiment at CERN investigates particle interactions.
- Understanding three-pion production is crucial for testing fundamental theories.
Purpose of the Study:
- To investigate the π- γ → π- π- π+ reaction using the Primakoff effect.
- To extract scattering intensity and cross-section of Coulomb production.
Main Methods:
- Utilized 190 GeV pions impinging on a lead target.
- Employed partial-wave analysis techniques to study the reaction.
- Isolated quasireal photon exchange via the Coulomb peak at low momentum transfers.
Main Results:
- Determined the absolute cross section in seven energy bins with 20% precision.
- Extracted scattering intensity dependence on the 3π-invariant mass.
- Observed agreement with chiral perturbation theory at leading order.
Conclusions:
- The experimental results validate predictions of chiral perturbation theory.
- Provides precise data for understanding low-energy pion interactions.
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