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Register a new user$D^*$ meson production in jet from combination of charm quark with light one
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In the framework of the perturbative Quantum Chromodynamics factorization, the cross section of the heavy meson production via the combination of a heavy quark with a light one can be factorized to be the convolution of the combination matrix element, the light quark distribution function, and the hard partonic sub-cross section of the heavy quark production. The partonic distribution and the combination matrix element are functions of a scaling variable, respectively, which is the momentum fraction of the corresponding quark with respect to the heavy meson. We studied the $D^{*pm}$ production in jet via combination in pp collision at the LHC. Our calculation can be summed with the fragmentation contribution, and the total result is comparable with the experimental data. The combination matrix elements can be further studied in various hadron production processes.
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We study $D$ - meson production at forward rapidities taking into account the non - linear effects in the QCD dynamics and the intrinsic charm component of the proton wave function. The total cross section, the rapidity distributions and the Feynman - $x$ distributions are calculated for $p p$ collisions at different center of mass energies. Our results show that, at the LHC, the intrinsic charm component changes the $D$ rapidity distributions in a region which is beyond the coverage of the LHCb detectors. At higher energies the IC component dominates the $y$ and $x_F$ distributions exactly in the range where the produced $D$ mesons decay and contribute the most to the prompt atmospheric neutrino flux measured by the ICECUBE Collaboration. We compute the $x_F$ - distributions and demonstrate that they are enhanced at LHC energies by approximately one order of magnitude in the $0.2 le x_F le 0.8$ range.
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We evaluate the s-wave interaction of pseudoscalar and vector mesons with both charm and beauty to investigate the possible existence of molecular $BD$, $B^*D$, $BD^*$, $B^*D^*$, $Bbar D$, $B^*bar D$, $Bbar D^*$ or $B^* bar D^*$ meson states. The scattering amplitude is obtained implementing unitarity starting from a tree level potential accounting for the dominant vector meson exchange. The diagrams are evaluated using suitable extensions to the heavy flavor sector of the hidden gauge symmetry Lagrangians involving vector and pseudoscalar mesons{, respecting heavy quark spin symmetry}. We obtain bound states at energies above 7 GeV for $BD$ ($J^P=0^+$), $B^*D$ ($1^+$), $BD^*$ ($1^+$) and $B^*D^*$ ($0^+$, $1^+$, $2^+$), all in isospin 0. For $Bbar D$ ($0^+$), $B^*bar D$ ($1^+$), $Bbar D^*$ ($1^+$) and $B^*bar D^*$ ($0^+$, $1^+$, $2^+$) we also find similar bound states in $I=0$, but much less bound, which would correspond to exotic meson states with $bar b$ and $bar c$ quarks, and for the $I=1$ we find a repulsive interaction. We also evaluate the scattering lengths in all cases, which can be tested in current investigations of lattice QCD.
We present recent results on light mesons based on Dalitz plot analyses of charm decays from Fermilab experiment E791. Scalar mesons are found to have large contributions to the decays studied, $D^+to K^-pi^+pi^+$ and $D^+, D_s^+topi^-pi^+pi^+$. From the $Kpipi$ final state, we find good evidence for the existence of the light and broad $kappa$ meson and we measure its mass and width. We also discuss recently published results on the 3$pi$ final states, especially the measurement of the $f_0$ parameters and the evidence for the $sigma$ meson from $D^+tosigmapi^+$. These results demonstrate the importance of charm decays as a new environment for the study of light meson physics.
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