A subtraction scheme for computing QCD jet cross sections at NNLO: regularization of doubly-real emissions

Abstract

We present a subtraction scheme for computing jet cross sections in electronpositron annihilation at next-to-next-to-leading order accuracy in perturbative QCD. In this first part we deal with the regularization of the doubly-real contribution to the NNLO correction.

A subtraction scheme for computing QCD jet cross sections at NNLO: regularization of real-virtual emission

“…In a companion paper [10] we generalized the dipole subtraction scheme to computing NNLO corrections to QCD jet cross sections to processes without coloured partons in the initial state. The scheme is completely general in the sense that any number of massless coloured final-state partons (massive vector bosons are assumed to decay into massless fermions) are allowed provided the necessary squared matrix elements are known.…”

“…As explained in ref. [10] we first continue analitically all integrals to d = 4 − 2ε dimensions and then rewrite eq. (1.1) as are approximate cross sections that regularize the doubly-real emission cross section in the one-and two-parton infrared regions of the phase space, respectively.…”

“…In ref. [10] we defined the subtraction terms for the doubly-real emissions; those to the real-virtual correction can be found in the present paper. By rendering these two contributions finite in d = 4 dimensions, the KLN theorem ensures that for infrared safe observables adding the subtractions above to the doublyvirtual correction that becomes also finite in d = 4 dimensions.…”

A subtraction scheme for computing QCD jet cross sections at NNLO: integrating the iterated singly-unresolved subtraction terms

“…refs. [1][2][3][4][5][6][7][8][9][10][11][12]. In very broad terms, when setting up any subtraction algorithm, two quite distinct difficulties must be addressed.…”

Real-virtual corrections for gluon scattering at NNLO

“…Subtraction schemes are a well established solution to this problem and several methods for systematically constructing general subtraction terms have been proposed in the literature at NLO [16][17][18][19][20] and at NNLO [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37]. Another NNLO subtraction type scheme has been proposed in [38].…”