We discuss a modification of the next-to-next-to-leading order (NNLO) subtraction scheme based on the residue-improved sector decomposition that reduces the number of double-real emission sectors from five to four. In particular, a sector where energies and angles of unresolved particles vanish in a correlated fashion is redundant and can be discarded. This simple observation allows us to formulate a transparent iterative subtraction procedure for double-real emission contributions, to demonstrate the cancellation of soft and collinear singularities in an explicit and (almost) process-independent way and to write the result of a NNLO calculation in terms of quantities that can be computed in four space-time dimensions. We illustrate this procedure explicitly in the simple case of O(αs2) gluonic corrections to the Drell–Yan process of qq¯ annihilation into a lepton pair. We show that this framework leads to fast and numerically stable computation of QCD corrections.

Nested soft-collinear subtractions in NNLO QCD computations / F. Caola, K. Melnikov, R. Röntsch. - In: THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS. - ISSN 1434-6044. - 77:4(2017), pp. 248.1-248.37. [10.1140/epjc/s10052-017-4774-0]

Nested soft-collinear subtractions in NNLO QCD computations

R. Röntsch
Ultimo
2017

Abstract

We discuss a modification of the next-to-next-to-leading order (NNLO) subtraction scheme based on the residue-improved sector decomposition that reduces the number of double-real emission sectors from five to four. In particular, a sector where energies and angles of unresolved particles vanish in a correlated fashion is redundant and can be discarded. This simple observation allows us to formulate a transparent iterative subtraction procedure for double-real emission contributions, to demonstrate the cancellation of soft and collinear singularities in an explicit and (almost) process-independent way and to write the result of a NNLO calculation in terms of quantities that can be computed in four space-time dimensions. We illustrate this procedure explicitly in the simple case of O(αs2) gluonic corrections to the Drell–Yan process of qq¯ annihilation into a lepton pair. We show that this framework leads to fast and numerically stable computation of QCD corrections.
Settore FIS/02 - Fisica Teorica, Modelli e Metodi Matematici
2017
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/903791
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