Raw R=0.4 signal, reference and $\Delta_{recoil}$ recoil jet distribution.

$\Delta_\mathrm{recoil}$ is calculated as:

$\Delta_\mathrm{recoil} = \frac{1}{N^\mathrm{AA}_\mathrm{trig}} \frac{\mathrm{d^2}N^\mathrm{AA}_\mathrm{{jet}}}{\mathrm{d}p^{\mathrm{ch}}_\mathrm{T,jet} \mathrm{d}\eta_\mathrm{jet}} \bigg|_{p_\mathrm{T,trig} \in \mathrm{TT_{Sig}}} - c_\mathrm{ref} \cdot \frac{1}{N^\mathrm{AA}_\mathrm{trig}} \frac{\mathrm{d^2}N^\mathrm{AA}_\mathrm{{jet}}}{\mathrm{d}p^{\mathrm{ch}}_\mathrm{T,jet} \mathrm{d}\eta_\mathrm{jet}} \bigg|_{p_\mathrm{T,trig} \in \mathrm{TT_{Ref}}}$.

Here $c_\mathrm{ref}$ is a scaling factor to account for conservation of jet density ( $c_\mathrm{ref} = 0.811$ for the R=0.4 analysis), and the trigger track intervals are in this analysis $TT_{Ref}: 5 <  p_\mathrm{T,trig} < 7$ GeV/c and $TT_{Sig}: 20 <  p_\mathrm{T,trig} < 50$ GeV/c. $\Delta_\mathrm{recoil}$ vs $p^{\mathrm{ch}}_\mathrm{T,jet}$ is measured in the back-to-back region of the azimuthal angle between the trigger track and recoil jet, $\Delta\phi$, where $|\Delta\phi - \pi| < 0.6$. Jets are reconstructed with charged particles with $p_{T,track} > 0.15$ GeV/c, using the anti-$k_T$ algorithm with resolution parameter R=0.4.

$p^{\mathrm{ch}}_\mathrm{T,jet}$ is corrected for the underlying event density, $\rho$, where $p^{\mathrm{ch}}_\mathrm{T,jet} = p_{\mathrm{T,jet}}^{\mathrm{raw}} - \rho \cdot A_\mathrm{jet} $. $\rho$ is corrected in the reference trigger track interval in order to align the jet energy scale of the recoil jet distributions in the signal and reference trigger track, by adding the difference between the mean of the $\rho$ distribution in the signal and reference trigger track intervals to $\rho$ in the reference interval, similar to the procedure described for the similar STAR measurement [1].

[1] Phys. Rev. C 96, 024905 (2017)