  We discuss studies on determination of fragmentation functions and an
application to exotic-hadron search by using characteristic differences between
favored and disfavored functions. The optimum fragmentation functions are
determined for pion, kaon, and proton in the leading order (LO) and
next-to-leading order (NLO) of the running coupling constant alpha_s by global
analyses of hadron-production data in electron-positron annihilation. Various
parametrization results are much different in disfavored-quark and gluon
fragmentation functions; however, we show that they are within uncertainties of
the determined functions by using the Hessian method for uncertainty
estimation. We find that the uncertainties are especially large in the
disfavored-quark and gluon fragmentation functions. NLO improvements are
explicitly shown in the determination by comparing uncertainties of the LO and
NLO functions. Next, we propose to use differences between favored and
disfavored fragmentation functions for determining internal quark
configurations of exotic hadrons. We make a global analysis for f_0 (980) for
finding its internal configuration; however, uncertainties are too large to
specify the structure at this stage.
