Effects of color reconnection on hadron flavor observables

We present a series of observables for soft inclusive physics, and utilize them for comparison between two recently developed color reconnection models: the new color reconnection model in pythia and the DIPSY rope hadronization model. The observables are ratios of identified hadron yields as a function of the final-state activity, as measured by the charged multiplicity. Since both considered models have a nontrivial dependence on the final-state activity, the above observables serve as excellent probes to test the effect of these models. Both models show a clear baryon enhancement with increasing multiplicity, while only the DIPSY rope model leads to a strangeness enhancement. Flowlike patterns, previously found to be connected to color reconnection models, are investigated for the new models. Only pythia shows a $p_{\perp }$-dependent enhancement of the $\mathrm{\Lambda }/K$ ratio as the final-state activity increases, with the enhancement being largest in the mid-$p_{\perp }$ region.

Figure 1

Sketch of how two $q\overline{q}$ dipoles (top) can be reconnected to different color topologies (left and right). The right connection gives rise to a double junction, which in turn will produce baryons. Notice that the placement of the pairs differs in the junction figure.

Figure 2

Comparison to $e^{+}{e}^{-}$ at 91.2 GeV from ALEPH, SLD and PDG.

Figure 3

Comparison to $pp$ data at 200 GeV from STAR (left) and at 7 TeV from ALICE and CMS (right).

Figure 4

Ratios of identified hadrons as functions of $N_{\text{ch}}^{\text{fwd}}$ at $\sqrt{s}=13\mathrm{TeV}$. The top row shows meson ratios with the numerator having one more strange quark than the denominator. The middle row shows baryon-to-meson ratios, with same amount of strange quarks. The bottom row shows baryon ratios with the numerator having one more strange quark than the denominator. Note that the vertical axis differs between the figures and that zero is suppressed.

Figure 5

Ratio of $\mathrm{\Lambda }/K$ as a function of $p_{\perp }$ in three bins of $N_{\text{ch}}^{\text{fwd}}$. In the right column the new color reconnection models are shown, and in the left column the old ones.