Observation of a Neutral Charmoniumlike State Z_{c}(4025)^{0} in e^{+}e^{-}→(D^{*}D[over ¯]^{*})^{0}π^{0}

Area of Science:

• Particle Physics and High-Energy Physics
• Quantum Chromodynamics (QCD) and Hadron Spectroscopy

Background:

• The BESIII detector at BEPCII collected data at center-of-mass energies of 4.23 GeV and 4.26 GeV.
• Previous studies have explored various processes involving electron-positron collisions to uncover new particles.

Purpose of the Study:

• To investigate the e^{+}e^{-}→(D^{*}D[over ¯]^{*})^{0}π^{0} process.
• To search for and characterize new resonant structures in the (D^{*}D[over ¯]^{*})^{0}π^{0} system.

Main Methods:

• Analysis of e^{+}e^{-} collision data samples with integrated luminosities of 1092 pb^{-1} at 4.23 GeV and 826 pb^{-1} at 4.26 GeV.
• Measurement of the π^{0} recoil mass spectrum to identify structures.
• Fitting the observed structure with a Breit-Wigner line shape to determine its properties.

Main Results:

• Observation of a new neutral structure, denoted as Z_{c}(4025)^{0}, near the (D^{*}D[over ¯]^{*})^{0} mass threshold.
• Determination of the Z_{c}(4025)^{0} pole mass as (4025.5_{-4.7}^{+2.0}±3.1) MeV/c^{2} and pole width as (23.0±6.0±1.0) MeV.
• Measurement of the Born cross sections for e^{+}e^{-}→Z_{c}(4025)^{0}π^{0}→(D^{*}D[over ¯]^{*})^{0}π^{0} at both energies.

Conclusions:

• The discovery of the Z_{c}(4025)^{0} provides new insights into the nature of exotic hadrons.
• This finding contributes to the ongoing exploration of the complex spectrum of QCD bound states.
• Further theoretical and experimental studies are warranted to understand the underlying mechanisms and quantum numbers of this new structure.