Modeling BSM effects on the Higgs transverse-momentum spectrum in an EFT approach

TL;DR

The paper addresses how beyond-the-Standard-Model physics can modify the Higgs pT spectrum in gluon fusion within a SMEFT framework. It computes the resummed pT distribution at NLL matched to NLO, including three dimension-six operators that alter top/bottom Yukawas and introduce a direct Hgg coupling. The results show that, while total rates can stay within current uncertainties, the pT shape can be significantly distorted, enabling discrimination of EFT effects in Run II. The work also discusses mass effects, resummation scales, EFT validity, and how to incorporate these effects in precision Higgs phenomenology.

Abstract

We consider the transverse-momentum distribution of a Higgs boson produced through gluon fusion in hadron collisions. At small transverse momenta, the large logarithmic terms are resummed up to next-to-leading-logarithmic (NLL) accuracy. The resummed computation is consistently matched to the next-to-leading-order (NLO) result valid at large transverse momenta. The ensuing Standard Model prediction is supplemented by possible new-physics effects parametrised through three dimension-six operators related to the modification of the top and bottom Yukawa couplings, and to the inclusion of a point-like Higgs-gluon coupling, respectively. We present resummed transverse-momentum spectra including the effect of these operators at NLL+NLO accuracy and study their impact on the shape of the distribution. We find that such modifications, while affecting the total rate within the current uncertainties, can lead to significant distortions of the spectrum. The proper parametrization of such effects becomes increasingly important for experimental analyses in Run II of the LHC.

Figures (6)

• Figure 1: Feynman diagrams contributing to $gg\rightarrow H$ production at LO. The possible insertions of dimension-six operators are marked by a cross in a circle.
• Figure 2: SM prediction of the Higgs transverse momentum distribution at NLL+NLO for (a) $0$ GeV$\le p_T \le400$ GeV and (b) $400$ GeV$\le p_T\le 800$ GeV, with uncertainty bands due to scale variations as outlined in the text.
• Figure 3: Higgs transverse-momentum spectrum in the SM (black, solid) compared to separate variations of the dimension-six operators for (a) $0$ GeV$\le p_T \le400$ GeV and (b) $400$ GeV$\le p_T\le 800$ GeV. The lower frame shows the ratio with respect to the SM prediction. The shaded band in the ratio indicates the uncertainty due to scale variations. See text for more details.
• Figure 4: Higgs transverse-momentum spectrum in the SM (black, solid) compared to simultaneous variations of $c_t$ and $c_g$ for (a) $0$ GeV$\le p_T \le400$ GeV and (b) $400$ GeV$\le p_T\le 800$ GeV. The lower frame shows the ratio with respect to the SM prediction. The shaded band in the ratio indicates the uncertainty due to scale variations. See text for more details.
• Figure 5: Higgs transverse-momentum spectrum in the SM (black, solid) compared to simultaneous variations of $c_t$ and $c_b$ for (a) $0$ GeV$\le p_T \le400$ GeV and (b) $400$ GeV$\le p_T\le 800$ GeV. The lower frame shows the ratio with respect to the SM prediction. The shaded band in the ratio indicates the uncertainty due to scale variations. See text for more details.