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Next-to-Leading-Order Corrections to the Production of Heavy-Flavour Jets in e+e- Collisions

P. Nason, C. Oleari

TL;DR

This work delivers a complete next-to-leading-order calculation of heavy-flavour jet production in e+e- collisions with finite quark masses. It employs a subtraction method to handle infrared and collinear divergences and produces a partonic event generator capable of computing infrared-safe observables. Real emission channels QQbar g, QQbar gg, and QQbar q qbar, together with virtual corrections, are treated with careful mass renormalization in a mixed scheme and extensive checks confirm consistency and correct massless limits. The results enable precise predictions of heavy-flavour dynamics and aid in αs determinations, with practical implementation demonstrated via a Fortran-based generator and several jet-shape observables.

Abstract

In this paper we describe the calculation of the process e+e- -> Z/gamma -> QQbar + X, where Q is a heavy quark, at order alpha_s^2.

Next-to-Leading-Order Corrections to the Production of Heavy-Flavour Jets in e+e- Collisions

TL;DR

This work delivers a complete next-to-leading-order calculation of heavy-flavour jet production in e+e- collisions with finite quark masses. It employs a subtraction method to handle infrared and collinear divergences and produces a partonic event generator capable of computing infrared-safe observables. Real emission channels QQbar g, QQbar gg, and QQbar q qbar, together with virtual corrections, are treated with careful mass renormalization in a mixed scheme and extensive checks confirm consistency and correct massless limits. The results enable precise predictions of heavy-flavour dynamics and aid in αs determinations, with practical implementation demonstrated via a Fortran-based generator and several jet-shape observables.

Abstract

In this paper we describe the calculation of the process e+e- -> Z/gamma -> QQbar + X, where Q is a heavy quark, at order alpha_s^2.

Paper Structure

This paper contains 19 sections, 161 equations, 3 figures, 9 tables.

Table of Contents

  1. Introduction
  2. Generalities
  3. Kinematics
  4. Three-body kinematics
  5. Four-body kinematics
  6. Outline of the calculation
  7. $Q\overline{Q}$ cross section
  8. $Q\overline{Q}g$ cross section at order $\alpha_s$
  9. Virtual contributions
  10. Soft and collinear limit of the $Q\overline{Q}gg$ and $Q\overline{Q}q\bar{q}$ cross sections
  11. Checks of the calculation
  12. Conclusion
  13. Phase space for four massive quarks
  14. Collinear limit for $g\hbox{$\rightarrow$} gg$ splitting
  15. Collinear limit for $g\hbox{$\rightarrow$} q \bar{q}$ splitting
  16. ...and 4 more sections

Figures (3)

  • Figure 1: Some of the diagrams contributing to the process $Z/\gamma\,\hbox{$\rightarrow$}\, Q\overline{Q}+X$: a Born graph (a), a virtual graph (b), a real emission graph (c) and a real emission graph with light quarks in the final state (d).
  • Figure 5: The two different areas in the $x_1$-$x_2$ plane correspond to the region I and to the region II of eq. (\ref{['eq:ps4']})
  • Figure 6: Gluon splitting