Combining resummed Higgs predictions across jet bins

Experimental analyses often use jet binning to distinguish between different kinematic regimes and separate contributions from background processes. To accurately model theoretical uncertainties in these measurements, a consistent description of the jet bins is required. We present a complete framework for the combination of resummed results for production processes in different exclusive jet bins, focusing on Higgs production in gluon fusion as an example. We extend the resummation of the $H+1$-jet cross section into the challenging low transverse momentum region, lowering the uncertainties considerably. We provide combined predictions with resummation for cross sections in the $H+0$-jet and $H+1$-jet bins, and give an improved theory covariance matrix for use in experimental studies. We estimate that the relevant theoretical uncertainties on the signal strength in the $H\to W{W}^{*}$ analysis are reduced by nearly a factor of 2 compared to the current value.

Figure 1

The fixed-order cross sections $\mathrm{\Delta }{\sigma }_0$ and $\mathrm{\Delta }{\sigma }_{\ge 2}$ defined in Eq. (25) as a function of $p_T^{\text{off}}$, with all other parameters as given in the figure.

Figure 2

Comparison of the one-jet cross section in bins of $p_{TJ}$. The direct (blue, hatched error bands) and indirect (red, solid error bands) approaches are shown. Scheme A is on the left, B is on the right (the two schemes are described in the text). The line at $p_T^{\text{off}}=60\mathrm{GeV}$ indicates that the indirect approach is used for $p_{TJ}<p_T^{\text{off}}$ and the direct approach is used for $p_{TJ}>p_T^{\text{off}}$.

Figure 3

Dependence on the parameter $p_T^{\text{off}}$, which is used to divide the indirect (used for $p_{TJ}<p_T^{\text{off}}$) and direct (used for $p_{TJ}>p_T^{\text{off}}$) evaluations of the one-jet cross section. The black points give the total one-jet rate (with total, yield, and migration uncertainties shown), and the green and orange points show the indirect and direct contributions respectively.

Figure 4

The cross sections in the zero-jet, one-jet, and inclusive two-jet bins for ATLAS (left) and CMS (right) parameter choices. In each jet bin, Scheme A (red left points) and Scheme B (blue, right points) are compared to the fixed-order results (black, middle points).