arXiv subjects

Rafael F. del Castillo

Publications and source records attributed to Rafael F. del Castillo.

4 recordsLinked to original sources

arXiv2024

One-loop evolution of twist-2 generalized parton distributions

We revisit the evolution of generalised parton distributions (GPDs) at the leading order in the strong coupling constant $α_s$ for all of the twist-2 quark and gluon operators. We rederive the relevant one-loop evolution kernels, expressing them in a form suitable for implementation, and check analytically that some basic properties, such as DGLAP/ERBL limits and polynomiality conservation, are fulfilled. We also present a number of numerical results obtained with a public implementation of the evolution in the library {\tt APFEL++} and available within the {\tt PARTONS} framework.

hep-ph↗

arXiv2024

Transverse Momentum Measurements with Jets at Next-to-Leading Power

In view of the increasing precision of theoretical calculations and experimental measurements, power corrections to transverse-momentum-dependent observables are highly important. We study the next-to-leading power corrections for transverse momentum measurements in $e^+ e^- \rightarrow 2$ jets. We obtain a factorized expression for the cross section, which involve twist-2 and twist-3 operators, and identify the new jet functions that appear in it. We calculate these jet functions at order αs for a family of recoil-free schemes, and provide the corresponding anomalous dimensions at leading order. Additionally, we show that the (endpoint) divergences that typically arise in sub-leading-power factorization can be subtracted and cancel for our case. By working with jets, everything is perturbatively calculable and there are substantial simplifications compared to the general next-to-leading power framework. Importantly, our analysis with jets can be extended to semi-inclusive deep-inelastic scattering, with the future Electron-Ion Collider as key application.

hep-ph↗

arXiv2022

Transverse momentum dependent distributions in dijet and heavy hadron pair production at EIC

We discuss the measurement of gluon transverse momentum distribution (TMD) in dijet and heavy hadron pair (HHP) production in semi-inclusive deep inelastic scattering. The factorization of these processes in impact parameter space shows the appearance of a specific new soft factor matrix element on top of angular a complex valued anomalous dimensions. We show in detail how these features can be treated consistently and we discuss a scale prescription for the evolution kernel of the dijet soft function. As a result we obtain phenomenological predictions for unpolarized and angular modulated cross-sections for the electron-ion collider (EIC) using current available information on unpolarized TMD.

hep-ph↗

arXiv2020

TMD factorization for dijet and heavy-meson pair in DIS

We study a transverse momentum dependent (TMD) factorization framework for the processes of di-jet and heavy meson pair production in deep-inelastic-scattering in an electron-proton collider, considering the measurement of the transverse momentum imbalance of the two hard probes in the Breit frame. For the factorization theorem we employ soft-collinear and boosted-heavy-quark effective field theories. The factorized cross-section for both processes is sensitive to gluon unpolarized and linearly polarized TMD distributions and requires the introduction of a new soft function. We calculate the new soft function here at one loop, regulating rapidity divergences with the $δ$-regulator. In addition, using a factorization consistency relation and a universality argument regarding the heavy-quark jet function, we obtain the anomalous dimension of the new soft function at two loops.

hep-ph↗