[Clascomment] OPT-IN:Multidimensional Measurements of Beam Single Spin Asymmetries in Semi-inclusive Deep-inelastic Charged Kaon Electroproduction off Protons in the Valence Region

[Mikhail Osipenko]

abstract: "where F^sin(phi)_LU is a twist-3 quantity" - perhaps, the leading twist, leading order term of F_LU is a twist-3

line 21: "in twist-2": do you mean "at twist-2"?

line-22: "twist-t describes the power suppression...", perhaps better to say "the contribution of twist-t operators in the process amplitude is suppressed by 2-t power of hard scale..."

line 24: "Higher-twist functions do not have a quark picture interpretation" - do you mean "parton model interpretation"? Many higher twists have a well defined quark picture interpretation(e.g. https://arxiv.org/pdf/hep-ph/0404195).

line 26: higher twists describe not "non-perturbative" (this is alpha_S expansion within each twist), but rather "non-local" QCD.

line 48: "This makes them difficult to measure at energies typical in colliding beam facilities, but they can be accessible at energies typical to fixed
target experiments." - this statement is incorrect, colliders cover low-Q2 region very well (see https://indico.cern.ch/event/686555/contributions/2960207/attachments/1681084/2700811/V_Myronenko_ICHEP2018.pdf)

line 168: there is no x_F cuts mentioned here, seen in some presentations. Are they not applied?

Figs.3-4: it looks like the contribution of g_\perp is compatible with zero everywhere. If it is correct, you may remove separate curves of e(x) and g_\perp terms (only confusing) and mention in text that g_\perp part is negligible according to the model [40,41].