Successive Combination Jet Algorithm For Hadron Collisions

TL;DR

The paper proposes a Durham-like successive-combination jet algorithm for hadron collisions, adapting ideas from e+e− jet definitions to produce infrared-safe, inclusive jet cross sections amid underlying-event activity. Jets are formed by iteratively merging nearby protojets in (E_T,η,φ) space with a distance measure d_ij that uses a tunable R parameter, ensuring a unique jet assignment without overlaps. Comparisons to the conventional cone algorithm show that, when R parameters are properly mapped (R_cone ≈ 1.35 × R_comb), the inclusive jet cross sections agree to within ~10% at order α_s^3, while the new method potentially reduces edge-of-cone and hadronization corrections. The authors argue that the successive-combination approach offers a robust, unambiguous jet definition with possible theoretical advantages, warranting further experimental and theoretical validation.

Abstract

Jet finding algorithms, as they are used in $e^+ e^-$ and hadron collisions, are reviewed and compared. It is suggested that a successive combination style algorithm, similar to that used in $e^+ e^-$ physics, might be useful also in hadron collisions, where cone style algorithms have been used previously.

Figures (3)

• Figure 1: Fraction of jet $E_T$ in angular annuli $r$ to $r+0.1$ comparing the cone algorithm with the the successive combination case. In both cases the jet has $R = 1.0$, $E_T =100$ GeV, $\sqrt{s} = 1800$ GeV, $0.1 < |\eta_J| < 0.7$ with renormalization/factorization scale $\mu = E_T/2$ and the structure functions of HMRS(B)HMRS.
• Figure 2: Order $\alpha_s^3$ inclusive jet cross section for $E_T=100$ GeV, $\sqrt{s}=1800$ GeV, averaged over $\eta_J$ in the range $0.1<|\eta_J|<0.7$ with the structure functions of HMRS(B)HMRS for the two algorithms specified in the text. The curves for the cone algorithm are: $\mu = E_T$ (solid), $\mu = E_T/2$ (dot-dash), $\mu = E_T/4$ (dot-dot-dot-dash); for the successive combination algorithm: $\mu = E_T$ (long dash), $\mu = E_T/2$ (medium dash), $\mu = E_T/4$ (short dash). a) Standard case plotted versus $R = R_{\rm cone} = R_{\rm comb}$. b) Same as a) except that the cone algorithm is plotted versus $R^\prime= 1.35 R_{\rm cone}$ while the successive combination case has $R^\prime=R_{\rm comb}$.
• Figure 3: Order $\alpha_s^3$ inclusive jet cross section as defined by the successive combination algorithm with $R_{\rm comb} = 1.0$ versus the jet $E_T$ for $\sqrt{s} = 1800$ GeV, $\mu = E_T/2$, averaged over $\eta_J$ in the range $0.1<|\eta_J|<0.7$ with the structure functions of HMRS(B)HMRS.