Measurements of the continuum R(uds) and R values in e(+)e(-) annihilation in the energy region between 3.650 and...

Area of Science:

• High-energy particle physics
• Quantum chromodynamics
• Hadron spectroscopy

Background:

• Understanding the behavior of quarks and gluons is crucial in quantum chromodynamics.
• Measurements of hadron production in electron-positron annihilation provide essential data for testing theoretical models.

Purpose of the Study:

• To measure the continuum R(uds) value near the center-of-mass energy of 3.70 GeV.
• To investigate R[uds(c)+psi(3770)](s) and R(had)(s) values in e(+)e(-) annihilation.
• To provide precise data for light hadron production near the DD threshold.

Main Methods:

• Utilized the BES-II detector at the BEPC Collider.
• Collected data across 68 energy points between 3.650 and 3.872 GeV.
• Analyzed electron-positron annihilation events to determine hadron production cross-sections.

Main Results:

• Measured the continuum R(uds) value for light hadron production near the DD threshold.
• Obtained R(uds) = 2.141 ± 0.025 ± 0.085.
• Acquired data on R[uds(c)+psi(3770)](s) and R(had)(s) in the specified energy range.

Conclusions:

• The measured R(uds) value offers a precise contribution to the understanding of light quark interactions.
• The data collected will aid in refining theoretical predictions for hadron production in e(+)e(-) annihilation.
• This study enhances the experimental database for particle physics research in the relevant energy region.