We study the effect of a hot and dense medium on the binding energy of hadronic molecules with open-charm mesons. We focus on a recent chiral quark-model-based prediction of a molecular state in the $N \bar D$ system. We analyze how the two-body thresholds and the hadron-hadron interactions are modified when quark and meson masses and quark-meson couplings change in a function of the temperature and baryon density according to predictions of the Nambu--Jona-Lasinio model. We find that in some cases the molecular binding is enhanced in medium as compared to their free-space binding. We discuss the consequences of our findings for the search for exotic hadrons in high-energy heavy-ion collisions as well as in the forthcoming facilities FAIR or J-PARC.
Dilepton production from hot hadronic matter is studied in an effective chiral Lagrangian with pions, $ρ$-mesons, and $a_1$ mesons, We find that the production rates from reactions that involve axial-vector mesons dominate over contributions from all other reactions when the dilepton invariant mass is above 1.5 GeV.
The drag and diffusion coefficients of a hot hadronic medium have been evaluated by using hidden charm mesons as probes. The matrix elements for the evaluation of these coefficients are calculated using an effective theory as well as from scattering lengths. Although the transport coefficients show a significant rise with temperature its effects on the suppression of $J/ψ$ in hadronic matter is not significant.
The one-loop self-energy of the $D$ and $D^*$ mesons in a hot hadronic medium is evaluated using the real time formalism of thermal field theory. The interaction of the heavy open-charm mesons with the thermalized constituents $(π,K,η)$ of the hadronic matter is treated in the covariant formalism of heavy meson chiral perturbation theory. The imaginary parts are extracted from the discontinuities of the self-energy function across the unitary and the Landau cuts. The non-zero contribution from the latter to the spectral density of $D$ and $D^*$ mesons opens a number of subthreshold decay chann…
The drag and diffusion coefficients of a hot hadronic medium consisting of pions, kaons and eta using open beauty mesons as a probe have been evaluated. The interaction of the probe with the hadronic matter has been treated in the framework of chiral perturbation theory. It is observed that the magnitude of both the transport coefficients are significant, indicating substantial amount of interaction of the heavy mesons with the thermal bath. The results may have significant impact on the experimental observables like the suppression of single electron spectra originating from the decays of hea…
We employ recently published cross sections for $D$-mesons with hadrons and calculate the drag and diffusion coefficients of $D$-mesons in hadronic matter as a function of the momentum of $D$-mesons as well as of the temperature of the medium. Calculating in our approach the spatial diffusion coefficient, $D_x$, at zero chemical potential we see a very smooth transition between our calculations for the hadron gas and the lattice QCD calculations. Applying the results for the transport coefficients of $D$-mesons in a Fokker-Planck equation, which describes the evolution of $D$-mesons during the…
The scattering cross sections of charm mesons with hadrons such as the pion, rho meson, and nucleon are studied in an effective Lagrangian. In heavy ion collisions, rescattering of produced charm mesons by hadrons affects the invariant mass spectra of both charm meson pairs and dileptons resulting from their decays. These effects are estimated for heavy ion collisions at SPS energies and are found to be significant.
The effective masses of the neutral mesons in a hadronic medium and under an external magnetic field are evaluated as functions of the baryonic density and the field intensity. For this purpose the meson polarization is evaluated in the one loop approximation using a Quantum Hadrodynamics model which includes pions, sigma, omega, and rho mesons. The propagators of the baryons include the full effect of the coupling to the magnetic field through their charges and their anomalous magnetic moments. Within the range of magnetic intensities considered here $10^{17}$ G $< B < 10^{19}$ G, the depende…
We review the recent results of heavy meson diffusion in thermal hadronic matter. The interactions of D and B-bar mesons with other hadrons (light mesons and baryons) are extracted from effective field theories based on chiral and heavy-quark symmetries. When these guiding principles are combined with exact unitarity, physical values of the cross sections are obtained. These cross sections (which contain resonant contributions) are used to calculate the drag and diffusion coefficients of heavy mesons immersed in a thermal and dense medium. The transport coefficients are computed using a Fokker…
We have developed a self-consistent theoretical approach to study the modification of the properties of heavy mesons in hot mesonic matter which takes into account chiral and heavy-quark spin-flavor symmetries. The heavy-light meson-meson unitarized scattering amplitudes in coupled channels incorporate thermal corrections by using the imaginary-time formalism, as well as the dressing of the heavy mesons with the self-energies. We report our results for the ground-state thermal spectral functions and the implications for the excited mesonic states generated dynamically in the heavy-light molecu…
We study the properties of the light vector mesons ($ρ$, $ω$ and $ϕ$) in strange hadronic matter using the QCD sum rule approach. The in-medium masses of the vector mesons are calculated from the modifications of the light quark condensates and the gluon condensates in the hadronic medium. The light quark condensates in the hadronic matter are obtained from the values of the non strange and strange scalar fields of the explicit chiral symmetry breaking term in a chiral SU(3) model. The in-medium gluon condensate is calculated through the medium modification of a scalar dilaton field, which is …
The Hidden Local Symmetry Lagrangian is used to study the interactions of phi mesons with other pseudoscalar and vector mesons in a hadronic gas at finite temperature. We have found a significantly small phi mean free path (less than 2.4 fm at T > 170 MeV) due to large collision rates with rho mesons, kaons and predominantly K* in spite of their heavy mass. This implies that phi mesons produced after hadronization in relativistic heavy ion collisions will not leave the hadronic system without scattering. The effect of these interactions on the time evolution of the phi density in the expanding…
We study the hadronic effects on the X(3872) meson abundance in heavy ion collisions. We evaluate the absorption cross sections of the X(3872) meson by pions and rho mesons in the hadronic stage of heavy ion collisions, and further investigate the variation in the X(3872) meson abundance during the expansion of the hadronic matter for its two possible quantum number states; $J^P=1^+$ and $2^-$. We show that the absorption cross sections and the time evolution of the X(3872) meson abundance are strongly dependent on the structure and quantum number of the X(3872) meson. We thus suggest that stu…
We calculate the effects of finite density of isospin asymmetric strange hadronic matter, for different strangeness fractions, on the in-medium properties of vector $\left( D^{\ast}, D_{s}^{\ast}, B^{\ast}, B_{s}^{\ast}\right)$ and axial-vector $\left( D_{1}, D_{1s}, B_{1}, B_{1s}\right)$ mesons using chiral hadronic SU(3) model and QCD sum rules. We focus on the evaluation of in-medium mass-shift and shift of decay constant of above vector and axial vector mesons. In QCD sum rule approach the properties e.g. masses and decay constants of vector and axial vector mesons are written in terms of …
We present effective-field-theory results with unitarized interactions on the D-meson transport coefficients in a gas populated by light mesons and baryons at finite temperature and baryochemical potential. The Fokker-Planck equation is used to compute the drag force, the relaxation time and the diffusion coefficients of D mesons for collisions at FAIR. At finite baryochemical potential, the combined effect of net baryonic density and sizable meson-baryon interaction makes the D mesons to relax more efficiently than in the case at zero baryochemical potential. We also describe the connection w…
Flux tube zero-point motion produces quark displacements transverse to the flux tube which make significant contributions to hadronic charge radii. In heavy quark systems, these contributions can be related by Bjorken's sum rule to the rates for semileptonic decay to hybrid mesons. This connection can be generalized to other leptoproduction processes, where transverse contributions to elastic form factor slopes are related to the cross sections for the production of the associated hybrid states. I identify the flux tube overlap integral responsible for these effects as the strong QCD analogue …
The cross sections for $J/ψ$ absorption by $π$ and $ρ$ mesons are studied in a meson-exchange model that includes not only pseudoscalar-pseudoscalar-vector-meson couplings but also three-vector-meson and four-point couplings. We find that they are much larger than in a previous study where only pseudoscalar-pseudoscalar-vector-meson couplings were considered. Including form factors at interaction vertices, the $J/ψ$ absorption cross sections $σ_{πψ}$ and $σ_{ρψ}$ are found to have values on the order of 7 mb and 3 mb, respectively. Their thermal averages in hadronic matter at temperature T=150…
There are generally two types of Wick contractions in lattice QCD calculations of a correlation function --- connected and disconnected ones. The disconnected contribution is difficult to calculate and noisy, thus it is often neglected. In the context of studying tetraquarks, hadronic molecules and meson-meson scattering, we show that whenever there are both connected and singly disconnected contractions, the singly disconnected part gives the leading order contribution, and thus should never be neglected. As an explicit example, we show that information about the scalar mesons sigma, f0(980),…
We provide a comprehensive review of hadronic decays of D and D_s mesons. We discuss current theoretical and experimental challenges and successes in understanding of hadronic transitions of those mesons. A brief overview of the theoretical and experimental tools are given before discussing the absolute branching fractions for D and D_s mesons. Cabibbo suppressed and rare hadronic decays are discussed and compared with theory before discussing our understanding of hadronic multibody decays.
The modification of the width of rho mesons due to in-medium decays and collisions is evaluated. The decay width is calculated from the imaginary part of the one-loop self-energy at finite temperature. The collision width is related to the cross sections of the $ρ$ + pion and the $ρ$ + nucleon reactions. A calculation based on an effective Lagrangian shows the importance of including the direct $ρπ\toρπ$ scattering which is dominated by the $a_1$ exchange. A large broadening of the spectral function is found, accompanied by a strength suppression at the pole.
We evaluate the in-medium $D$ and $\bar D$-meson masses in hot hadronic matter induced by interactions with the light hadron sector described in a chiral SU(3) model. The effective Lagrangian approach is generalized to SU(4) to include charmed mesons. We find that the D-mass drops substantially at finite temperatures and densities, which open the channels of the decay of the charmonium states ($Ψ^\prime$, $χ_c$, $J/Ψ$) to $D \bar D$ pairs in the thermal medium. The effects of vacuum polarisations from the baryon sector on the medium modification of the $D$-meson mass relative to those obtained…
We calculate the effects of finite density and temperature of isospin asymmetric strange hadronic matter, for different strangeness fractions, on the in-medium properties of vector $\left( D^{\ast}, D_{s}^{\ast}, B^{\ast}, B_{s}^{\ast}\right)$ and axial-vector $\left( D_{1}, D_{1s}, B_{1}, B_{1s}\right)$ mesons, using chiral hadronic SU(3) model and QCD sum rules. We focus on the evaluation of in-medium mass-shift and shift in decay constant of above vector and axial-vector mesons. In QCD sum rule approach, the properties, e.g., the masses and decay constants of vector and axial-vector mesons …
We study unpolarized cross sections for the endothermic nonresonant reactions: pion pion to rho rho for I=2, KK to K*K* for I=1, KK* to K*K* for I=1, pion K to rho K* for I=3/2, pion K* to rho K* for I=3/2, rho K to rho K* for I=3/2, and pion K* to rho K for I=3/2, which take place in hadronic matter. We provide a potential that is given by perturbative QCD with loop corrections at short distances, becomes a distance-independent and temperature-dependent value at long distances, and has a spin-spin interaction with relativistic modifications. The Schrodinger equation with the potential yields …
K*-charmonium dissociation reactions in hadronic matter are studied in the Born approximation, in the quark-interchange mechanism, and with a temperature-dependent quark potential. We obtain the temperature dependence of unpolarized cross sections for K*-charmonium dissociation reactions which produce charmed mesons and charmed strange mesons. We use the cross sections for charmonium dissociation in collisions with pion, rho meson, kaon, vector kaon, and eta meson to calculate dissociation rates of charmonium with the five types of mesons. Because of the temperature dependence of the meson mas…
The $NDΛ_c$ and $ND^*Λ_c$ form factors are evaluated in a full QCD sum rule calculation. We study the double Borel sum rule for the three point function of one meson one nucleon and one $Λ_c$ current up to order six in the operator product expansion. The double Borel transform is performed with respect to the nucleon and $Λ_c$ momenta, and the form factor is evaluated as a function of the momentum $Q^2$ of the heavy meson. These form factors are relevant to evaluate the charmonium absorption cross section by hadrons. Our results are compatible with constant form factors in these vertices.
Meson-meson reactions A(q_1 \bar{q}_1) + B(q_2 \bar{q}_2) to q_1 + \bar{q}_1 + q_2 + \bar{q}_2 in high-temperature hadronic matter are found to produce an appreciable amount of quarks and antiquarks freely moving in hadronic matter and to establish a new mechanism for deconfinement of quarks and antiquarks in hadronic matter.
We study kaon-charmonium and eta-charmonium dissociation reactions. The K-charmonium dissociation and the eta-charmonium dissociation include 27 reactions. Cross sections for the reactions are calculated in the Born approximation, in the quark-interchange mechanism and with a temperature-dependent quark potential. The temperature dependence of peak cross sections of endothermic reactions is linked to the temperature dependence of quark-antiquark relative-motion wave functions, meson masses and the quark potential. Although the eta meson and kaon have similar masses, the energy and temperature …
The in-medium mass and decay width of the $ϕ$ meson in the hot asymmetric strange hadronic matter are calculated using an effective Lagrangian approach for $ϕ$ $K\bar K$ interaction. The in-medium contributions of $K \bar K$ loop to the $ϕ$ meson self-energy are computed by the medium modified kaon and antikaon mass which is evaluated using the chiral SU(3) model. To deal with the ultraviolet divergence, we regularize the loop integral of self-energy with a dipole form factor, and present the results for cut-off mass, $Λ_c$=3 GeV. In chiral model calculations, for strange matter, we find that …
Within the independent-harmonic-oscillator model for quarks inside a hadron, a rigorous method is presented for the calculation of coupling constants and transition potentials for hadronic decay, as needed in a multi-channel description of mesons.
We give the first estimate of charmless scalar meson emitting weak hadronic decays of 0 $\Lembda_{b}^{0}$, $Ξ_{b}^{0}$ and $Ξ_{b}^{-}$ bottom baryons employing the pole model and consequently predict their branching ratios.
We investigate meson and nucleon dynamics at finite baryon density and temperature by coupling the nucleon field and the omega meson to the three-flavor linear sigma model and calculate hadronic properties around the nuclear liquid-gas transition. We apply the functional renormalization group method, and find that mesonic fluctuations increase the strength of the coefficient of the $U_A(1)$ breaking determinant operator as a function of the chiral condensate. As a consequence, we find that the actual value of the anomaly increases discontinuously at the first order nuclear liquid-gas transitio…
Masses and decay constants of scalar $D_0$ and $D_{s0}$ mesons in isospin asymmetric strange hadronic matter at finite temperature are evaluated using QCD sum rules and chiral SU(3) model. In-medium light quark condensates, $\left\langle \bar{u}u\right\rangle_{ρ_{B}}$ and $\left\langle \bar{d}d\right\rangle_{ρ_{B}}$, the strange quark condensates, $\left\langle \bar{s}s\right\rangle_{ρ_{B}}$, and the gluon condensates, $\left\langle \frac{α_{s}}π {G^a}_{μν} {G^a}^{μν} \right\rangle_{ρ_{B}}$, needed in QCD sum rule calculations are evaluated using chiral SU(3) model. As an application, we calcu…
Electromagnetic current-current correlators in pionic and nucleonic medium have been evaluated in the static limit to obtain electrical conductivities for pion and nucleon components respectively, where former decreases and latter one increases with the variation of temperature $T$ and baryon chemical potential $μ_N$. Therefore, total electrical conductivity of pion and nucleon system exhibits a valley structure in the $T$-$μ_N$ plane. To get non-divergent and finite values of correlators, finite thermal widths of medium constituents, pion and nucleon have been considered, where these thermal …
We expose the current experimental and theoretical situation of the interesting case of the production of phi mesons in up to very high energy collisions of hadrons on both nucleon and nuclear targets, and we present a quantitavely good theoretical description of the corresponding experimental data, based on the formalism of the well established Quark-Gluon String Model, that has proved to be valid for a wide energy range. All the available experimental data for phi-meson production in hadron-nucleon collisions on the spectra of secondary phi, and on the ratios of phi/pi(-) and phi/K(-) produc…
Properties of scalar mesons below 1.0 GeV have been studied by regarding them as hadronic molecular states. Using the effective Lagrangian approach, we have calculated their leptonic decays, strong decays and productions via the $ϕ$ meson radiative decays. Comparing our results with that given in the literature and the data, we conclude that it is difficult to arrange them in the same nonet if some of them are pure hadronic molecules.
We review studies of inelastic meson-meson scattering. In nonperturbative schemes with chiral-perturbation-theory Lagrangians and in models based on effective meson Lagrangians, inelastic meson-meson scattering leads to the successful identification of resonances in meson-meson reactions, adequate inclusion of final state interactions in particle decays, and so on. For mesons of which each consists of a quark and an antiquark, inelastic meson-meson scattering may be caused by quark-antiquark annihilation, quark-antiquark creation, quark interchange, and quark-antiquark annihilation and creatio…
We investigate the in-medium masses of open charm mesons ($D$($D^0$, $D^+$), $\bar{D}$($\bar{D^0}$, $D^-$), $D_s$(${D_{s}}^+$, ${D_{s}}^-$)) and charmonium states ($J/ψ$, $ψ(3686)$, $ψ(3770)$, $χ_{c0}$, $χ_{c2}$) in strongly magnetized isospin asymmetric strange hadronic matter using a chiral effective model. In the presence of the magnetic field, the number density and scalar density of charged baryons have contributions from Landau energy levels. The mass modifications of open charm mesons arise due to their interactions with nucleons, hyperons, and the scalar fields (the non-strange field $…
The existence of hadronic molecular-type hybrids consisting of a baryon and a meson is argued. Long-range interactions due to one-pion exchange is shown to be strong enough to produce a loosely bound state. Specific features of a molecular hybrid are discussed.
The in-medium properties of $D_S$ mesons are investigated within the framework of an effective hadronic model, which is a generalization of a chiral SU(3) model, to SU(4), in order to study the interactions of the charmed hadrons. In the present work, the $D_s$ mesons are observed to experience net attractive interactions in a dense hadronic medium, hence reducing the masses of the $D_S^+$ and $D_S^-$ mesons from the vacuum values. While this conclusion holds in both nuclear and hyperonic media, the magnitude of the mass drop is observed to intensify with the inclusion of strangeness in the me…
We evaluate the drag and diffusion coefficients of a hot hadronic medium consisting of pions, nucleons, kaons and eta using open charm mesons as a probe. The interaction of the probe with the hadronic matter has been treated in the framework of effective field theory. It is observed that the magnitude of both the transport coefficients are significant, indicating substantial amount of interaction of the heavy mesons with the thermal hadronic system. The results may have noticeable impact on the experimental observable like the suppression of single electron spectra originating form the decays …
With quark-antiquark annihilation and creation in the first Born approximation, we study the reactions: $K \bar {K} \to K \bar {K}^\ast, ~K \bar{K} \to K^* \bar{K}, ~πK \to πK^\ast, ~πK \to ρK, ~ππ\to K \bar{K}^\ast, ~ππ\to K^\ast \bar{K}, ~ππ\to K^\ast \bar{K}^\ast, ~πρ\to K \bar{K}, ~πρ\to K^\ast \bar{K}^\ast, ~ρρ\to K^\ast \bar{K}^\ast, ~K \bar{K}^\ast \to ρρ$, and $K^* \bar{K} \to ρρ$. Unpolarized cross sections for the reactions are obtained from transition amplitudes that are composed of mesonic quark-antiquark relative-motion wave functions and the transition potential for quark-antiqua…
We study the $K^*$ meson reduction in heavy ion collisions by focusing on the hadronic effects on the $K^*$ meson abundance. We evaluate the absorption cross sections of the $K^*$ and $K$ meson by light mesons in the hadronic matter, and further investigate the variation in the meson abundances for both particles during the hadronic stage of heavy ion collisions. We show how the interplay between the interaction of the $K^*$ meson and kaon with light mesons in the hadronic medium determines the final yield difference of the statistical hadronization model to the experimental measurements. For …
Accessing Exotic Hadronic States via Charmed-Meson Femtoscopy in Relativistic Heavy-Ion Collisions
Helmholtz Research Academy Hesse for FAIR (HFHF)（黑森FAIR亥姆霍兹研究学院）；GSI Helmholtz Center for Heavy Ion Physics（GSI重离子物理亥姆霍兹中心）；Institut für Theoretische Physik, Johann Wolfgang Goethe-Universität（约翰·沃尔夫冈·歌德大学理论物理研究所）；GSI Helmholtzzentrum für Schwerionenforschung GmbH（GSI重离子研究亥姆霍兹有限公司）；SUBATECH, Nantes University, IMT Atlantique, IN2P3/CNRS（南特大学SUBATECH实验室（隶属于IMT大西洋、IN2P3/CNRS））；Frankfurt Institute for Advanced Studies（法兰克福高等研究院）
We summarize the studies on the hadronic production of S- and P-wave $(\bar bc)$ mesons via direct fragmentation of the bottom antiquark as well as the Altarelli-Parisi induced gluon fragmentation.
We computed the hadronic vacuum-polarization contributions to the muon anomalous magnetic moment $a_μ(hadr.)$ by using the QCD model with infinite number of vector mesons [1,2]. The result is $a_μ(hadr.) = 663(23) \times 10^{-10}$. }
Dilepton production from resonance scattering in hot hadronic matter is studied. Including the widths of these resonances, which enhance the phase space for dilepton production, we find that the production rate is significantly increased if a resonance appears in the extended phase space. For the reaction $π+ρ\to l^++l^-$, the finite $ρ$ meson width extends the invariant mass below the $ω$-meson mass, so a peak at the $ω$ meson mass is seen in the dilepton spectrum. Similarly, a $ρ$-meson peak appears in the reaction $ρ+ρ\to l^++l^-$. On the other hand, the effect of particle widths in the rea…
Production of $ϕ$ mesons is considered in the course of heavy-ion collisions at SPS energies. We investigate the possible difference in momentum distributions of $ϕ$ mesons measured via their leptonic ($μ^+μ^-$) and hadronic ($K^+K^-$) decays. Rescattering of secondary kaons in the dense hadron gas together with the influence of in-medium kaon potential can lead to a relative decrease of a $ϕ$ yield observed in the hadronic channel. We analyze how the in-medium modifications of meson properties affect apparent - reconstructed momentum distributions of $ϕ$ mesons. Quantitative results are prese…
Perturbative cross section for direct B_c meson production in gluon gluon scattering g g --> B_c^+ b \bar{c} is calculated and compared with other existing results. Predictions for hadronic B_c production at Tevatron and LHC are presented and the main sources of uncertainties are discussed.
The energetic exclusive two-body nonleptonic decays of B mesons are investigated in the framework of the relativistic quark model within the factorization approximation.
We review recent results on hadronic B meson decays including rare as well as non-suppressed decays. The main emphasis is on those channels relevant to measurement of CP violation in the coming B factories. After briefly describing flavor-tagged charm counting, we cover B -> DK(*), B -> charmless 2-body decays, inclusive eta' production, and final-state-interaction phases in B -> Psi K* and B -> D* rho.
We consider spin effects in two-particle hadronic decays of B_c and B_c^* mesons into J/psi plus ρ(π) in the frame work of hard gluon exchange model. It is shown that polarization of the J/psi meson is very different in decays of B_c and B_c^* mesons as well as their decay widths into J/psi plus ρ(π).
We review recent experimental results on hadronic decays and lifetimes of hadrons containing b and c quarks. We discuss charm counting and the semileptonic branching fraction in B decays, the color suppressed amplitude in B and D decay, and the search for gluonic penguins in B decay.
Lattice QCD determinations appropriate to hadron spectroscopy are reviewed with emphasis on the glueball and hybrid meson states in the quenched approximation. Hybrids are discussed for heavy and for light quarks. The effects of sea quarks (unquenching) are explored.
Two of the approaches to the hadronic productions of the double heavy mesons $B_c$ and $B_c^*$ are investigated. Comparison in various aspects on the results obtained by the approaches is made and shown in figures and a table. Some trial understanding of the approaches themselves and the achieved results is presented. The results may be used as some references for discovering the mesons at Tevatron and LHC.
The identification of problematic meson states as the members of the quark model $q\bar{q}$ nonets by using a hadronic resonance spectrum is discussed. The results favor the currently adopted $q\bar{q}$ assignments for the axial-vector, tensor, and 1 $^3F_4$ $J^{PC}=4^{++}$ meson nonets, and suggest a new $q\bar{q}$ assignment for the scalar meson nonet which favors the interpretation of the $f_0(980)$ and $f_0(1710)$ mesons as non-$q\bar{q}$ objects. We also suggest that the 2 $^3S_1$ $\frac{1}{2}(1^{-})$ state should be identified with the $K^\ast (1680)$ rather than $K^\ast (1410)$ meson.
Withdrawn by arXiv administration because the text and equations were plagiarized from chapter 10 of the BaBar Physics Book http://www.slac.stanford.edu/pubs/slacreports/slac-r-504.html See also hep-ph/0304045
Nonperturbative effects in $D$-meson production in pion-nucleon and proton-nucleon collisions are investigated within the recombination model. The coalescence of perturbatively created charm quarks with sea- and valence-quarks from projectile and target fragments is shown to be competitive in magnitude with standard fragmentation calculations at both central (small $x_F$) and forward rapidities. Corresponding flavor asymmetries for inclusive $D$-meson production are thus mostly generated on the (light-) parton distribution level, and turn out to be in reasonable overall agreement with availabl…
