Jet azimuthal angle correlations in the production of a Higgs boson pair plus two jets at hadron colliders

TL;DR

This paper analyzes azimuthal angle correlations of two jets in Higgs boson pair production at hadron colliders, revealing distinct patterns for gluon fusion and weak boson fusion processes and their sensitivity to various parameters.

Contribution

It provides a detailed study of jet azimuthal correlations in Higgs pair production, highlighting differences between gluon fusion and weak boson fusion mechanisms and effects of top mass and parity violation.

Findings

Gluon fusion shows strong azimuthal correlations in jet angles.

Weak boson fusion correlations are mainly kinematic, not quantum-induced.

Correlations are sensitive to top quark mass and Higgs self-coupling variations.

Abstract

Azimuthal angle correlations of two jets in the process $pp\to HHjj$ are studied. The loop induced $\mathcal{O}(\alpha_s^4 \alpha_{}^2)$ gluon fusion (GF) sub-process and the $\mathcal{O}(\alpha_{}^4)$ weak boson fusion (WBF) sub-process are considered. The GF sub-process exhibits strong correlations in the azimuthal angles $\phi_{1,2}^{}$ of the two jets measured from the production plane of the Higgs boson pair and the difference between these two angles $\phi_1^{}-\phi_2^{}$, and a very small correlation in the sum of them $\phi_1^{}+\phi_2^{}$. The impact of using a finite top mass $m_t^{}$ value on the correlations is found crucial. The transverse momentum of the Higgs boson can be used to enhance or suppress the correlations. The impact of a non-standard value for the triple Higgs self-coupling on the correlations is found much smaller than that on other observables, such as the invariant mass of the two Higgs bosons. The peak shifts of the azimuthal angle distributions reflect the magnitude of parity violation in the $gg\to HH$ amplitude and the dependence of the distributions on parity violating phases is analytically clarified. The WBF sub-process also produces correlated distributions and it is found that they are not induced by the quantum effect of the intermediate weak bosons but mainly by a kinematic effect. This kinematic effect is a characteristic feature of the WBF sub-process and is not observed in the GF sub-process. It is found that the correlations are different in the GF and in the WBF sub-processes. As part of the process dependent information, they will be helpful in the analyses of both the GF sub-process and the WBF sub-process at the LHC.