First extraction of Interference Fragmentation Functions from e+e- data

TL;DR

This paper presents the first extraction of interference fragmentation functions from e+e- data, revealing a nonzero asymmetry linked to quark polarization, achieved through Monte Carlo simulations due to missing unpolarized data.

Contribution

It introduces the first measurement of interference fragmentation functions from e+e- annihilation data, utilizing Monte Carlo simulations to compensate for missing unpolarized cross section data.

Findings

Detected a nonzero azimuthal asymmetry in dihadron pairs.

Extracted polarized dihadron fragmentation functions.

Demonstrated the feasibility of using simulations for unpolarized functions.

Abstract

We report on the first extraction of interference fragmentation functions from the semi-inclusive production of two hadron pairs in back-to-back jets in e+e- annihilation. A nonzero asymmetry in the correlation of azimuthal orientations of opposite \pi+\pi- pairs is related to the transverse polarization of fragmenting quarks through a significant polarized dihadron fragmentation function. Extraction of the latter requires the knowledge of its unpolarized counterpart, the probability density for a quark to fragment in a \pi+\pi- pair. Since data for the unpolarized cross section are missing, we extract the unpolarized dihadron fragmentation function from a Monte Carlo simulation of the cross section.