Non-perturbative QCD effects in q T spectra of Drell-Yan and Z-boson production

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Abstract:We study the power corrections to Transverse Momentum Distributions (TMDs) by analyzing renormalon divergences of the perturbative series. The renormalon divergences arise independently in two constituents of TMDs: the rapidity evolution kernel and the small-b matching coefficient. The renormalon contributions (and consequently power corrections and non-perturbative corrections to the related cross sections) have a non-trivial dependence on the Bjorken variable and the transverse distance. We discuss the consistency requirements for power corrections for TMDs and suggest inputs for the TMD phenomenology in accordance with this study. Both unpolarized quark TMD parton distribution function and fragmentation function are considered.

Section: Jhep03(2017)002supporting

confidence: 93%

“…The same model is also the core of the RESBOS program package [28] which is widely used in applications. On another hand, the implementation of TMDPDFs by [29] does not use b * -prescription. They have found that part of the non-perturbative corrections (essentially to the TMD evolution kernel) are negligible.…”

Section: Jhep03(2017)002mentioning

confidence: 99%

Power corrections and renormalons in Transverse Momentum Distributions

Scimemi

Vladimirov

2017

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“…realizations used in refs. [1,11,25,39,41,42]. In this way the traditional implementation of the TMD cross-section contains four renormalization scale entries of the perturbative series and consequently four scales µ.…”

Section: Jhep08(2018)003mentioning

confidence: 99%

Systematic analysis of double-scale evolution

Scimemi

Vladimirov

2018

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164

Often the factorization of differential cross sections results in the definition of fundamental hadronic functions/distributions which have a double-scale evolution, as provided by a pair of coupled equations. Typically, the two scales are the renormalization and rapidity scales. The two-dimensional structure of their evolution is the object of the present study. In order to be more specific, we consider the case of the transverse momentum dependent distributions (TMD). Nonetheless, most of our findings can be used with other double-scale parton distributions. On the basis of the two-dimensional structure of TMD evolution, we formulate the general statement of the ζ-prescription introduced in [1], and we define an optimal TMD distribution, which is a scaleless model-independent universal non-perturbative function. Within this formulation the non-perturbative definition of the distribution is disentangled from the evolution, which clarifies the separation of perturbative and non-perturbative effects in the phenomenology. A significant part of this work is devoted to the study of the effects of truncation of perturbation theory on the double-scale evolution. We show that within truncated perturbation theory the solution of evolution equations is ambiguous and this fact generates extra uncertainties within the resummed cross-section. The alternatives to bypass this issue are discussed. Finally, we discuss the sources and distribution of the scale variation uncertainties.

“…Resummations have been previously been discussed within an SCET [9][10][11][12] framework [29,30,[32][33][34][35][37][38][39] as well as in the CSS resummation formalism [40][41][42][43][44][45]. While formally most of the these…”

Section: Introductionmentioning

confidence: 99%

The Higgs transverse momentum distribution at NNLL and its theoretical errors

Neill¹,

Rothstein

Vaidya

2015

In this letter, we present the NNLL-NNLO transverse momentum Higgs distribution arising from gluon fusion. In the regime p ⊥ m h we include the resummation of the large logs at next to next-to leading order and then match on to the α 2 s fixed order result near p ⊥ ∼ m h . By utilizing the rapidity renormalization group (RRG) we are able to smoothly match between the resummed, small p ⊥ regime and the fixed order regime. We give a detailed discussion of the scale dependence of the result including an analysis of the rapidity scale dependence. Our central value differs from previous results, in the transition region as well as the tail, by an amount which is outside the error band. This difference is due to the fact that the RRG profile allows us to smoothly turn off the resummation.