Measurement of the J/Psi Meson and b-Hadron Production Cross Sections in ppbar Collisions at sqrt s = 1960 GeV
D. Acosta, CDF Collaboration
TL;DR
The study measures inclusive and differential production cross sections for $J/\psi$ mesons and $b$-hadrons in $p\bar{p}$ collisions at $\sqrt{s}=1960$ GeV using $J/\psi \rightarrow \mu^+\mu^-$ decays with the CDF Run II detector. By exploiting lifetime information to separate prompt $J/\psi$ from $b$-hadron decays, the authors extract the first total $b$-hadron cross section down to $p_T=0$ and provide high-precision inclusive and differential cross sections, including a central rapidity region $|y|<0.6$. The results confront QCD-based production models, including NRQCD color-octet mechanisms, and offer essential benchmarks for heavy-flavor production predictions in hadron colliders. Overall, the measurements advance understanding of heavy-quarkonium and $b$-hadron production and constrain theoretical descriptions of their production dynamics at high energy.
Abstract
We present a new measurement of the inclusive and differential production cross sections of $J/ψ$ mesons and $b$-hadrons in proton-antiproton collisions at $\sqrt{s}=1960$ GeV. The data correspond to an integrated luminosity of 39.7 pb$^{-1}$ collected by the CDF Run II detector. We find the integrated cross section for inclusive $J/ψ$ production for all transverse momenta from 0 to 20 GeV/$c$ in the rapidity range $|y|<0.6$ to be $4.08 \pm 0.02 (stat)^{+0.36}_{-0.33} (syst) μ{\rm b}$. We separate the fraction of $J/ψ$ events from the decay of the long-lived $b$-hadrons using the lifetime distribution in all events with $p_T(J/ψ) > 1.25$ GeV/$c$. We find the total cross section for $b$-hadrons, including both hadrons and anti-hadrons, decaying to $J/ψ$ with transverse momenta greater than 1.25 GeV/$c$ in the rapidity range $|y(J/ψ)|<0.6$, is $ 0.330 \pm 0.005 (stat) ^{+0.036}_{-0.033} (syst) ~μ{\rm b}$. Using a Monte Carlo simulation of the decay kinematics of $b$-hadrons to all final states containing a $J/ψ$, we extract the first measurement of the total single $b$-hadron cross section down to zero transverse momentum at $\sqrt{s}=1960$ GeV. We find the total single $b$-hadron cross section integrated over all transverse momenta for $b$-hadrons in the rapidity range $|y|<0.6$ to be $ 17.6 \pm 0.4 (stat)^{+2.5}_{-2.3} (syst) μ{\rm b}$.