Factorized power expansion for high-pT heavy quarkonium production

Area of Science:

• High Energy Physics
• Quantum Chromodynamics
• Particle Physics

Background:

• Nonrelativistic Quantum Chromodynamics (NRQCD) factorization is a key framework for studying heavy quarkonium production.
• Previous NRQCD calculations often encountered large next-to-leading order corrections, complicating predictions.
• Understanding heavy quarkonium production at high transverse momentum (pT) is crucial for testing fundamental theories.

Purpose of the Study:

• To investigate the role of next-to-leading power contributions in heavy quarkonium production.
• To demonstrate how an extended NRQCD formalism can simplify high pT calculations.
• To analyze the impact of these contributions on leading NRQCD production channels and polarization.

Main Methods:

• Incorporating factorized cross sections with next-to-leading power contributions for heavy quark pair production.
• Utilizing fragmentation functions for heavy quark pairs and light partons.
• Calculating fragmentation functions within the NRQCD framework.

Main Results:

• The extended formalism naturally reproduces all high pT results previously calculated using NRQCD factorization.
• Two leading NRQCD production channels, (3)S(1)([1]) and (1)S(0)([8]), are found to be dominated by next-to-leading power contributions over a wide pT range.
• Large NRQCD next-to-leading order corrections are effectively absorbed into the leading order of the first power correction.

Conclusions:

• The inclusion of next-to-leading power contributions offers a more streamlined approach to NRQCD calculations for heavy quarkonium production.
• This finding has significant implications for understanding heavy quarkonium production dynamics and polarization.
• The dominance of next-to-leading power contributions simplifies the interpretation of experimental data.