Angular and momentum asymmetry in particle production at high energies

TL;DR

This work investigates angular and momentum asymmetries in central-rapidity two-particle production at high energies using high-energy ($k_\perp$) factorization with unintegrated gluon distributions. By decomposing cross sections into off-shell parton flux convolutions and off-shell partonic amplitudes, the authors show that produced particle pairs are not necessarily back-to-back and may carry unequal transverse momenta, especially when $k_\perp$ is not much larger than the intrinsic flux scales. They derive and analyze the structure of the two-particle cross section, including a collinear-like singular region as $\Delta y,\Delta\phi\to 0$, and demonstrate that the observed angular decorrelation $\rho(\Delta\phi)$ and momentum disbalance depend sensitively on the choice of unintegrated distributions and on the collider energy. The findings highlight the limitations of collinear factorization in semihard regimes and motivate further work on NLO BFKL and nonlinear evolutions to better describe final-state correlations in high-energy hadronic processes.

Abstract

Angular asymmetry and momentum disbalance for a pair of particles produced at high energy in central rapidity region are studied. The asymmetry is substantial for small momenta of produced particles but diminishes when they rise.

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