Fragmentation Functions Of Mesons Research Articles

Determination of meson fragmentation functions in the Field-Feynman model

We study the fragmentation functions of both pions and kaons in the Field-Feynman recursive model with the extended SU(2) flavor symmetry relations of fragmentation functions and fitting parameters. Parametrizations are determined from a leading-order (LO) analysis of HERMES experimental multiplicity data of meson production in semi-inclusive deep inelastic scattering, and uncertainties are estimated with the Hessian method. We compare our results with the experimental data and the analysis results of other parametrizations. The SU(2) flavor symmetry breaking effect of meson fragmentation functions of $ud$ quarks is also discussed, and we show that the fragmentation functions of kaons have a bigger SU(2) flavor symmetry breaking effect of $ud$ quarks than these of pions.

Using hadron-in-jet data in a global analysis of D* fragmentation functions

We present a novel global QCD analysis of charged $D^{*}$-meson fragmentation functions at next-to-leading order accuracy. This is achieved by making use of the available data for single-inclusive $D^{*}$-meson production in electron-positron annihilation, hadron-hadron collisions, and, for the first time, in-jet fragmentation in proton-proton scattering. It is shown how to include all relevant processes efficiently and without approximations within the Mellin moment technique, specifically for the in-jet fragmentation cross section. The presented technical framework is generic and can be straightforwardly applied to future analyses of fragmentation functions for other hadron species, as soon as more in-jet fragmentation data become available. We choose to work within the Zero Mass Variable Flavor Number Scheme which is applicable for sufficiently high energies and transverse momenta. The obtained optimum set of parton-to-$D^{*}$ fragmentation functions is accompanied by Hessian uncertainty sets which allow one to propagate hadronization uncertainties to other processes of interest.

Fragmentation functions of neutral mesons π0 and k0 with Laplace transform approach

With an analytical solutions of DGLAP evolution equations based on the Laplace transform method, we find the fragmentation functions (FFs) of neutral mesons, [Formula: see text] and [Formula: see text] at NLO approximation. We also calculated the total fragmentation functions of these mesons and compared them with experimental data and those from global fits. The results show a good agreement between our solutions and other models and they are compatible with experimental data.

Spin-dependent energy distribution of B-hadrons from polarized top decays considering the azimuthal correlation rate

Basically, the energy distribution of bottom-flavored hadrons produced through polarized top quark decays t(↑)→W++b(→Xb), is governed by the unpolarized rate and the polar and the azimuthal correlation functions which are related to the density matrix elements of the decay t(↑)→bW+. Here we present, for the first time, the analytical expressions for the O(αs) radiative corrections to the differential azimuthal decay rates of the partonic process t(↑)→b+W+ in two helicity systems, which are needed to study the azimuthal distribution of the energy spectrum of the hadrons produced in polarized top decays. These spin-momentum correlations between the top quark spin and its decay product momenta will allow the detailed studies of the top decay mechanism. Our predictions of the hadron energy distributions also enable us to deepen our knowledge of the hadronization process and to test the universality and scaling violations of the bottom-flavored meson fragmentation functions.

FRAGMENTATION FUNCTIONS OF GLUON SPLITTING INTO CHARMED HADRONS IN THE RECOMBINATION MODEL

In the framework of the recombination model we determine the shower parton distributions (SPDs) with the fragmentation functions (FFs) for mesons and then predict the fragmentation functions for baryons. We get the fragmentation functions of gluon splitting into charmed hadrons. We show the relationship of fragmentation functions for mesons and baryons and find that they are not independent if the hadronization of the shower partons is taken into account.

Fragmentation Functions for Heavy Baryons in the Recombination Model

Using the shower parton distributions determined by the recombination model, we predict the fragmentation functions for heavy baryons. Then we obtain the completed fragmentation functions of heavy quarks (c and b) splitting into their hadrons (mesons and baryons containing one heavy valence quark). The calculated process shows that the fragmentation functions for mesons and baryons are not independent if the hadronization of the shower partons is taken into account.

Photon-tagged heavy meson production in high energy nuclear collisions

We study the photon-triggered light and heavy meson production in both p+p and A+A collisions. We find that a parton energy loss approach that successfully describes inclusive hadron attenuation in nucleus-nucleus reactions at RHIC can simultaneously describe well the experimentally determined photon-triggered light hadron fragmentation functions. Using the same framework, we generalize our formalism to study photon-triggered heavy meson production. We find that the nuclear modification of photon-tagged heavy meson fragmentation functions in A+A collision is very different from that of the photon-tagged light hadron case. While photon-triggered light hadron fragmentation functions in A+A collisions are suppressed relative to p+p, photon-triggered heavy meson fragmentation functions can be either enhanced or suppressed, depending on the specific kinematic region. The anticipated smaller energy loss for $b$-quarks manifests itself as a flatter photon-triggered $B$-meson fragmentation function compared to that for the $D$-meson case. We make detailed predictions for both RHIC and LHC energies. We conclude that a comprehensive comparative study of both photon-tagged light and heavy meson production can provide new insights in the details of the jet quenching mechanism.

Fragmentation production of charmed hadrons in electron-positron annihilation

The processes of D^{(*)}-mesons and \Lambda_c-baryons production in e^+e^--annihilation at 10.58 GeV and 91.18 GeV energies are concerned. At the 10.58 GeV energy the production of charmed particles via the B-mesons decays is also concerned. Scaling violation of the fragmentation functions is calculated at the NLL-accuracy. Nonperturbative fragmentation functions are retrieved from the experimental data of B-factories and are approximated by simple analytic expressions. It is proved, that the difference between nonperturbative fragmentation functions of mesons and baryons can be easily explained by quark counting.

Fragmentation functions of mesons in the Field-Feynman model

The fragmentation functions of the pion with distinction between $D_{u}^{\pi^{+}}$, $D_{d}^{\pi^{+}}$, and $D_{s}^{\pi^{+}}$ are studied in the Field-Feynman recursive model, by taking into account the flavor structure in the excitation of quark-antiquark pairs by the initial quarks. The obtained analytical results are compatible with available empirical results. The framework is also extended to predict the fragmentation functions of the kaon with distinction between $D_{\bar{s}}^{K^{+}}(z)$, $D_{u}^{K^{+}}(z)$, $D_{s}^{K^{+}}(z)$, and $D_{d}^{K^{+}}(z)$. This work gives a significant modification of the original model, and the predictions can be tested by future experiments on the fragmentation functions of the kaon.

Light meson production at the Fermilab Tevatron to next-to-leading order.

Inclusive production of light mesons (${\mathrm{\ensuremath{\pi}}}^{0}$,\ensuremath{\eta},${\mathrm{\ensuremath{\pi}}}^{\ifmmode\pm\else\textpm\fi{}}$,${\mathit{K}}^{\ifmmode\pm\else\textpm\fi{}}$) at the Fermilab Tevatron is considered in QCD to next-to-leading order in the formalism of fragmentation functions. We present various distributions of phenomenological interest, along with a new set of K meson fragmentation functions. The fragmentation properties of jets in charged and neutral pions are also considered.

E + e − Production of heavy quarks in the string model

The string model of Artru and Mennessier predicts that the fragmentation functions for mesons containing heavy quarks are concentrated near fractional momentumz∼1, with width ∼1/μ where μ is the mass of the heavy quark.