# Measurements of $e^+e^-$ pairs from open heavy flavor in $p$+$p$ and $d$+$A$ collisions at $\sqrt{s_{NN}}=200$ GeV

## TL;DR

This study measures electron-positron pairs from heavy-flavor decays in proton-proton collisions at 200 GeV, comparing data with simulations and examining potential nuclear effects.

## Contribution

It provides the first detailed separation of $bar{b}$ and $car{c}$ contributions in $p$+$p$ collisions at this energy using multiple event generators.

## Key findings

- All three generators describe the data within detector acceptance.
- Significant differences in total cross sections when extrapolating to full phase space.
- No observable nuclear modification in $p$+$p$ versus $d$+$A$ collisions.

## Abstract

We report a measurement of $e^+e^-$ pairs from semileptonic heavy-flavor decays in $p$+$p$ collisions at $\sqrt{s_{NN}}=200$~GeV. The $e^+e^-$ pair yield from $b\bar{b}$ and $c\bar{c}$ is separated by exploiting a double differential fit done simultaneously in dielectron invariant mass and $p_T$. We used three different event generators, {\sc pythia}, {\sc mc@nlo}, and {\sc powheg}, to simulate the $e^+e^-$ spectra from $c\bar{c}$ and $b\bar{b}$ production. The data can be well described by all three generators within the detector acceptance. However, when using the generators to extrapolate to $4\pi$, significant differences are observed for the total cross section. These difference are less pronounced for $b\bar{b}$ than for $c\bar{c}$. The same model dependence was observed in already published $d$+$A$ data. The $p$+$p$ data are also directly compared with $d$+$A$ data in mass and $p_T$, and within the statistical accuracy no nuclear modification is seen.