ISR physics at BABAR

TL;DR

This paper presents a method to measure low-energy e+e- annihilation cross sections using initial-state radiation at BABAR, providing new data on known and new resonances, baryon form factors, and potential new states.

Contribution

It introduces a novel ISR-based measurement technique at BABAR and reports new experimental results on various hadronic processes and resonances.

Findings

Measured cross sections for multiple e+e- annihilation processes.

Improved parameters of known resonances based on new data.

Observed new states Y(4260) and Y(2175).

Abstract

A method of measuring e+e- annihilation cross sections at low energy sqrt{s}< 5 GeV, using initial-state radiation, is described. Experimental data from the PEP-II B-factory at 10.6 GeV center-of-mass energy, obtained via ISR, are presented. The cross sections are measured for many processes e+e- --> 3pi, 4pi, 2K pi, 2K 2pi, 4K, p anti-p, Lambda anti-Lambda, D anti-D, ... . From the measured cross sections the parameters of known resonances are improved, the baryons form factors are derived and compared with theory predictions. New states, e.g; Y(4260) and Y(2175), for which the internal structure is not yet established, are observed.