Search for resonances decaying to eta_c pi+ pi- in two-photon interactions

TL;DR

This study searches for specific resonances decaying to eta_c pi+ pi- in two-photon interactions but finds no significant signals, setting upper limits on their production rates and branching ratios.

Contribution

First comprehensive search for these resonances in two-photon interactions with new upper limits on their production and decay properties.

Findings

No significant signals observed for any resonance.

Upper limits set on two-photon widths times branching fractions.

Constraints on branching ratios of eta_c(2S) and chi_{c2}(1P) decays.

Abstract

We report a study of the process gamma gamma -> X -> eta_c pi+ pi-, where X stands for one of the resonances chi_{c2}(1P), eta_c(2S), X(3872), X(3915), or chi_{c2}(2P). The analysis is performed with a data sample of 473.9 fb^{-1} collected with the BaBar detector at the PEP-II asymmetric-energy electron-positron collider. We do not observe a significant signal for any channel, and calculate 90% confidence-level upper limits on the products of branching fractions and two-photon widths Gamma(X -> gamma gamma)BR(X -> eta_c pi+ pi-): 15.7 eV for chi_{c2}(1P), 133 eV for eta_c(2S), 11.1 eV for X(3872) (assuming it to be a spin-2 state), 16 eV for X(3915) (assuming it to be a spin-2 state), and 19 eV for chi_{c2}(2P). We also report upper limits on the ratios of branching fractions BR(eta_c(2S) -> eta_c pi+ pi-)/BR(eta_c(2S)-> K_S^0 K+ pi-) < 10.0 and BR(chi_{c2}(1P) -> eta_c pi+ pi-)/BR(chi_{c2}(1P)-> K_S^0 K+ pi-) <32.9 at the 90% confidence level.