Scattering Amplitudes (IMAGE) Institute for Advanced Study Caption Two sound waves (1 and 2) are produced, scattering into two other sound waves (3 and 4), which are then detected. The probability for this process is described by a 4-point scattering amplitude. Credit Angelo Esposito Usage Restrictions No restrictions. License Public Domain Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.