  We report measurements of the production cross sections of charged pions,
kaons, and protons as a function of fractional energy, the event-shape variable
called thrust, and the transverse momentum with respect to the thrust axis.
These measurements access the transverse momenta created in the fragmentation
process, which are of critical importance to the understanding of any
transverse momentum dependent distribution and fragmentation functions. The low
transverse momentum part of the cross sections can be well described by
Gaussians in transverse momentum as is generally assumed but the
fractional-energy dependence is non-trivial and different hadron types have
varying Gaussian widths. The width of these Gaussians decreases with thrust and
shows an initially rising, then decreasing fractional-energy dependence. The
widths for pions and kaons are comparable within uncertainties, while those for
protons are significantly narrower. These single-hadron cross sections and
Gaussian widths are obtained from a $558\,{\rm fb}^{-1}$ data sample collected
at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB
asymmetric-energy $e^+ e^-$ collider.
