Evidence for simultaneous production of $J/\psi$ and $\Upsilon$ mesons

TL;DR

This paper presents evidence for the simultaneous production of $J/ar{psi}$ and $mbda$ mesons in proton-antiproton collisions, providing insights into gluon-gluon interactions and the spatial distribution of initial partons.

Contribution

First evidence of simultaneous $J/ar{psi}$ and $mbda$ meson production in proton-antiproton collisions, with measurement of the effective cross section $ff$.

Findings

Effective cross section $ff=2.2\, ext{mb}$ with statistical and systematic uncertainties.

Supports gluon-gluon interactions as the dominant production mechanism.

Provides data on the initial parton spatial distribution in proton-antiproton collisions.

Abstract

We report evidence for the simultaneous production of $J/\psi$ and $\Upsilon$ mesons in 8.1 fb$^{-1}$ of data collected at $\sqrt{s}=$1.96 TeV by the D0 experiment at the Fermilab $p \bar p$ Tevatron Collider. Events with these characteristics are expected to be produced predominantly by gluon-gluon interactions. In this analysis, we extract the effective cross section characterizing the initial parton spatial distribution, $\sigma_{eff}=2.2\pm 0.7\mbox{(stat)} \pm 0.9 \mbox{(syst)} ~\mbox{mb}$.