Soft-gluon resummation for slepton-pair production at hadron colliders

TL;DR

The paper addresses the need for high-precision predictions of slepton-pair production at hadron colliders by performing soft-gluon resummation in momentum space using soft-collinear effective theory (SCET) up to N^3LL and matching to NLO. It extends previous Drell-Yan/SUSY analyses by including SUSY QCD corrections to the hard coefficient and providing a detailed phenomenological study for the Tevatron and LHC, including scale-setting and invariant-mass distributions. The results show that resummation significantly improves perturbative stability and only modestly increases cross sections, while virtual SUSY effects remain smaller than residual theoretical uncertainties, suggesting PDFs and SUSY spectrum parameters dominate the remaining errors. Overall, the work demonstrates a robust SCET-based approach that yields sub-percent level scale uncertainties and offers precise predictions for slepton searches and mass extraction at hadron colliders.

Abstract

We use a recent approach to soft-gluon resummation based on effective field theory to implement soft-gluon resummation at NNNLL order for slepton-pair production in SUSY extensions of the Standard Model. This approach resums large logarithmic corrections arising from the dynamical enhancement of the partonic threshold region caused by steeply falling parton luminosities. We evaluate the resummed invariant-mass distribution and total cross section for slepton-pair production at the Tevatron and LHC, matching our results onto NLO fixed-order calculations. As a byproduct, we also study virtual SUSY effects in the context of soft-gluon resummation for the Drell-Yan process.

Figures (6)

• Figure 1: Relative contribution of the one-loop correction to the soft function to the cross section for slepton-pair production at the LHC ($\sqrt{s}=7$ TeV), for different values of the pair invariant mass $M$ (left). For each value of $M$ we determine the soft scale by taking the point at which the correction is minimal (right).
• Figure 2: Factorization-scale dependence of the $K$-factor for slepton-pair production at the LHC in fixed-order perturbation theory (left) and after soft-gluon resummation (right). The NNLO$^*$ and N$^3$LL+NLO results contain only the leading singular two-loop corrections.
• Figure 4: Comparison of one-loop contributions to the hard matching coefficient $C_V$ arising in the SM (solid lines) and in its SUSY extensions (dashed lines).
• Figure 6: Drell-Yan rapidity distribution at fixed $M=1600$ GeV at different orders in perturbation theory. In both plots, the left half refers to fixed-order perturbation theory, while the right half includes the effects of soft-gluon resummation. The plot on the left refers to the SM, while the one on the right shows the effects of virtual squarks and gluinos by the dashed bands.
• Figure 7: Invariant-mass distributions for slepton-pair production at the Tevatron and LHC. The plots on the left show fixed-order results at LO and NLO, while those on the right include the effects of soft-gluon resummation at NLL and N$^3$LL+NLO. The bands indicate the uncertainty associated with scale variations.