Resolving the Higgs-gluon coupling with jets

In the Standard Model, the Higgs coupling to gluons is almost entirely induced by top quark loops. We derive the logarithmic structure of Higgs production in association with two jets. Just like in the one-jet case, the transverse momentum distributions exhibit logarithms of the top quark mass and can be used to test the nature of the loop–induced Higgs coupling to gluons. Using Higgs decays to W bosons and to tau leptons, we show how the corresponding analyses hugely benefit from the second jet in the relevant signal rate as well as in the background rejection.

Figure 1

Sample Feynman diagrams for the processes $qq\to Hgg$ and $gq\to Hgq$, indicating the cuts which contribute to absorptive parts.

Figure 2

Differential distributions for $m_{Hjj}$ (left) and for $m_{Hj}$ (right) for the $Hjj$ process. The Standard Model curves include the full top mass dependence, while the low- energy effective field theory approximation (HEFT) relies on the approximation in Eq. (2). The index qq (gq) indicates Feynman diagrams with an incoming quark pair (gluon quark). We assume $\sqrt{S}=13\mathrm{TeV}$.

Figure 3

Left to right: correlation plots for the leading $p_{T,j}$ vs $Q_1$ and $p_{T,H}$ vs $Q_1$ for $Hjj$ production in the Standard Model, ${\kappa }_{t,g}=(1,0)$. We also show the ratio SM/BSM, where BSM is defined as ${\kappa }_{t,g}=(0.8,0.2)$.

Figure 4

Parton–level $p_{T,H}$ (left) and $p_{T,j_1}$ (right) distributions for $Hj$ and $Hjj$ production. The red curve corresponds to the Standard Model ${\kappa }_{t,g}=(1,0)$, while the blue curves follow from the BSM hypothesis ${\kappa }_{t,g}=(0.8,0.2)$. We assume $\sqrt{S}=13\mathrm{TeV}$.

Figure 5

Parton–level $m_{jj}$ (left), $p_{z,j_1}$ (center), and $p_{z,H}$ (right) distributions for $Hjj$ production.

Figure 6

Transverse momentum distribution for $Hj$ production (based on Mcfm) and $Hjj$ production (based on Vbfnlo). Both codes use Pythia8 for the parton shower. The top-induced and dimension-6 contributions as well as their interference are defined in Eq. (10). We assume $\sqrt{S}=13\mathrm{TeV}$ and for technical reasons include a decay $H\to \tau \tau$ with minimal cuts.

Figure 7

Normalized $\mathrm{\Delta }{\varphi }_{jj}$ (left) and $p_{T,j1}/p_{T,j2}$ (right) distributions for the $H\to WW$ signal and the dominant backgrounds. All universal cuts listed in Table 1 are already applied.

Figure 8

Normalized $\mathrm{\Delta }{\varphi }_{jj}$ (left) and $p_{T,j1}/p_{T,j2}$ (right) distributions for the $H\to \tau \tau$ signal and the dominant backgrounds. All universal cuts listed in Table 2 are already applied.

Figure 9

Confidence level for separating the BSM hypotheses ${\kappa }_{t,g}=(0.7,0.3)$ from the Standard Model. We show results for $H\to WW$ decays based on the transverse momentum of the Higgs (left) and the hardest jet (center). For the $H\to \tau \tau$ decays (right), we limit ourselves to the more promising case of the Higgs transverse momentum.