Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

Towards NNLL resummation: hard matching coefficients for squark and gluino hadroproduction

W. Beenakker, T. Janssen, S. Lepoeter, M. Krämer, A. Kulesza, E. Laenen, I. Niessen, S. Thewes, T. Van Daal

TL;DR

This work provides the hard matching coefficients needed for NNLL threshold resummation of squark and gluino hadroproduction in SUSY-QCD by deriving them from the NLO cross section near threshold. It first constructs an SU(Nc) colour basis suitable for diagonalizing colour structures at threshold and then enumerates which colour representations contribute for each production channel due to symmetry constraints. The hard matching coefficients are computed by combining real and virtual NLO contributions, with all expressions and cross-checks documented in Appendices. Numerically, the coefficients have a substantial impact on cross sections, especially for final states with gluinos, and their dependence on the squark-gluino mass ratio is analyzed to inform precise LHC predictions.

Abstract

We present the hard matching coefficients for squark and gluino hadroproduction. The hard matching coefficients follow from the next-to-leading order cross section near threshold and are an important ingredient for performing threshold resummation at next-to-next-to-leading logarithmic accuracy. We discuss the calculation, list the analytical results and study the numerical impact of these corrections. We find that the impact of the hard matching coefficients can be considerable, with the largest effect observed for final states involving gluinos.

Towards NNLL resummation: hard matching coefficients for squark and gluino hadroproduction

TL;DR

This work provides the hard matching coefficients needed for NNLL threshold resummation of squark and gluino hadroproduction in SUSY-QCD by deriving them from the NLO cross section near threshold. It first constructs an SU(Nc) colour basis suitable for diagonalizing colour structures at threshold and then enumerates which colour representations contribute for each production channel due to symmetry constraints. The hard matching coefficients are computed by combining real and virtual NLO contributions, with all expressions and cross-checks documented in Appendices. Numerically, the coefficients have a substantial impact on cross sections, especially for final states with gluinos, and their dependence on the squark-gluino mass ratio is analyzed to inform precise LHC predictions.

Abstract

We present the hard matching coefficients for squark and gluino hadroproduction. The hard matching coefficients follow from the next-to-leading order cross section near threshold and are an important ingredient for performing threshold resummation at next-to-next-to-leading logarithmic accuracy. We discuss the calculation, list the analytical results and study the numerical impact of these corrections. We find that the impact of the hard matching coefficients can be considerable, with the largest effect observed for final states involving gluinos.

Paper Structure

This paper contains 9 sections, 13 equations, 1 figure.

Table of Contents

  1. Introduction
  2. Construction of the colour bases in SU($\bf N_c$)
  3. Suppressed cross sections
  4. $q_iq_i\to{\tilde{q}}_i{\tilde{q}}_i$: only the symmetric colour structure contributes.
  5. $gg\to{\tilde{q}}{\bar{\tilde{q}}}$: only the symmetric colour structures contribute.
  6. $gg\to{\tilde{g}}{\tilde{g}}$: only the symmetric colour structures contribute.
  7. $q\bar{q}\to{\tilde{g}}{\tilde{g}}$: only the antisymmetric colour structure contributes.
  8. Calculation of the hard matching coefficients
  9. Numerical properties of the hard matching coefficients

Figures (1)

  • Figure :