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arXiv · 2003.07453

Predictive power of transverse-momentum-dependent distributions

Manvir Grewal·Zhong-Bo Kang·Jian-Wei Qiu·Andrea Signori
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Abstract

We investigate the predictive power of transverse-momentum-dependent (TMD) distributions as a function of the light-cone momentum fraction $x$ and the hard scale $Q$ defined by the process. We apply the saddle point approximation to the unpolarized quark and gluon transverse momentum distributions and evaluate the position of the saddle point as a function of the kinematics. We determine quantitatively that the predictive power for an unpolarized transverse momentum distribution is maximal in the large-$Q$ and small-$x$ region. For cross sections the predictive power of the TMD factorization formalism is generally enhanced by considering the convolution of two distributions, and we explicitly consider the case of $Z$ and $H^0$ boson production. In the kinematic regions where the predictive power is not maximal, the distributions are sensitive to the non-perturbative hadron structure. Thus, these regions are critical for investigating hadron tomography in a three-dimensional momentum space.

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Manvir Grewal, Zhong-Bo Kang, Jian-Wei Qiu, Andrea Signori. 2020-03-16. Predictive power of transverse-momentum-dependent distributions. https://doi.org/10.1103/physrevd.101.114023

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