Phenomenology of TMD parton distributions in Drell-Yan and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msup> <mml:mi>Z</mml:mi> <mml:mn>0</mml:mn> </mml:msup> </mml:math> boson production in a hadron structure oriented approach

Abstract

We present a first practical implementation of a recently proposed hadron structure oriented (HSO) approach to transverse momentum dependent (TMD) phenomenology applied to Drell-Yan-like processes, including lepton pair production at moderate <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:msup> <a:mi>Q</a:mi> <a:mn>2</a:mn> </a:msup> </a:math> and <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"> <c:msup> <c:mi>Z</c:mi> <c:mn>0</c:mn> </c:msup> </c:math> boson production. We compare and contrast general features of our methodology with other common practices and emphasize aspects that we view as improvements. Separately, we discuss the importance of treatments that preserve various theoretical properties of the nonperturbative parts of TMD parametrizations for future applications that have the extraction of hadron structure as a primary goal. These include the HSO’s preservation of a basic TMD parton-model-like framework even while accounting for full TMD factorization and evolution, explicit preservation of the integral relationship between TMD and collinear parton density functions, and the ability to meaningfully compare different theoretical models of nonperturbative TMD parton distributions. In our examples, we show that there is significant sensitivity at moderate <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"> <e:msup> <e:mi>Q</e:mi> <e:mn>2</e:mn> </e:msup> </e:math> to both the form of the nonperturbative transverse momentum dependence and the parametrization of collinear parton densities. However, we also find that evolving to <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"> <g:msup> <g:mi>Q</g:mi> <g:mn>2</g:mn> </g:msup> <g:mo>=</g:mo> <g:msubsup> <g:mi>M</g:mi> <g:mi>Z</g:mi> <g:mn>2</g:mn> </g:msubsup> </g:math> , without fitting, results in a satisfactory postdiction of existing data for <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"> <i:msup> <i:mi>Z</i:mi> <i:mn>0</i:mn> </i:msup> </i:math> production, nearly independently of the modeling of nonperturbative transverse momentum behavior. We argue that this demonstrates that moderate <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"> <k:mi>Q</k:mi> </k:math> measurements should be given greater weight than high <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" display="inline"> <m:mi>Q</m:mi> </m:math> measurements in extractions of nonperturbative transverse momentum dependence. We also obtain new extractions of the nonperturbative Collins-Soper kernel within the HSO approach. We discuss its features and compare with some earlier extractions. Published by the American Physical Society 2024

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