K∗0K^{*0} and Σ∗\Sigma^* production in Au+Au collisions at sNN=\sqrt{s_{NN}}= 200 GeV and 62.4 GeV

Applying a quark combination model for the hadronization of Quark Gluon Plasma (QGP) and A Relativistic Transport (ART) model for the subsequent hadronic rescattering process, we investigate the production of $K^{*0}$ and $\Sigma^*$ resonances in central Au+Au collisions at $\sqrt{s_{NN}}=$ 200 GeV and 62.4 GeV. The initial $K^{*0}$ produced via hadronization is higher than the experimental data in the low $p_T$ region and is close to the data at 2-3 GeV/c. We take into account the hadronic rescattering effects which lead to a strong suppression of $K^{*0}$ with low $p_T$, and find that the $p_T$ spectrum of $K^{*0}$ can be well described. According to the suppressed magnitude of $K^{*0}$ yield, the time span of hadronic rescattering stage is estimated to be about 13 fm/c at 200 GeV and 5 fm/c at 62.4 GeV. The $p_T$ spectrum of $\Sigma^*$ directly obtained by quark combination hadronization in central Au+Au collisions at 200 GeV is in well agreement with the experimental data, which shows a weak hadronic rescattering effects. The elliptic flow v2 of $\Sigma^*$ in minimum bias Au+Au collisions at 200 GeV and $p_T$ spectrum of $\Sigma^*$ at lower 62.4 GeV are predicted.Comment: 12 pages, 6 figure

New feature of low pTp_{T} charm quark hadronization in pppp collisions at s=7\sqrt{s}=7 TeV

Treating the light-flavor constituent quarks and antiquarks that can well describe the data of light-flavor hadrons in $pp$ collisions at $\sqrt{s}=7$ TeV as the underlying source of chromatically neutralizing the charm quarks of low transverse momenta ($p_{T}$), we show that the experimental data of $p_{T}$ spectra of single-charm hadrons $D^{0,+}$, $D^{*+}$ $D_{s}^{+}$, $\Lambda_{c}^{+}$ and $\Xi_{c}^{0}$ at mid-rapidity in the low $p_{T}$ range ($2\lesssim p_{T}\lesssim7$ GeV/$c$) in $pp$ collisions at $\sqrt{s}=7$ TeV can be well understood by the equal-velocity combination of perturbatively-created charm quarks and those light-flavor constituent quarks and antiquarks. This suggests a possible new scenario of low $p_{T}$ charm quark hadronization, in contrast to the traditional fragmentation mechanism, in $pp$ collisions at LHC energies. This is also another support for the exhibition of the effective constituent quark degrees of freedom for the small parton system created in $pp$ collisions at LHC energies.Comment: 7 pages, 5 figure

Multiplicity fluctuation and correlation of mesons and baryons in ultra-relativistic heavy-ion collisions at LHC

We study the multiplicity fluctuation and correlation of identified mesons and baryons formed at the hadronization by the quark combination mechanism in the context of ultra-relativistic heavy-ion collisions. Based on the statistical method of free quark combination, we derive the two-hadron multiplicity correlations such as meson-meson and meson-baryon correlations, and take the effects of quark number fluctuation at hadronization into account by a Taylor expansion method. After including the decay contributions, we calculate the dynamical fluctuation observable $\nu_{dyn}$ for $\text{K}\pi$, $p\pi$ and $\text{K}p$ pairs and discuss what underlying physics can be obtained by comparing with the data in Pb-Pb collisions at $\sqrt{s_{NN}}=2.76$ TeV and the simulations from HIJING and AMPT event generators.Comment: 8 pages, 3 figure

Zb/Zb′→ΥπZ_b/Z_b^\prime \to \Upsilon\pi and hbπh_b \pi decays in intermediate meson loops model

With the recent measurement of $Z_b(10610)$ and $Z_b(10650)\to B\bar{B}^*+c.c.$ and $B^*\bar{B}^*$, we investigate the transitions from the $Z_b(10610)$ and $Z_b(10650)$ to bottomonium states with emission of a pion via intermediate $B \ {B}^*$ meson loops. The experimental data can be reproduced in this approach with a commonly accepted range of values for the form factor cutoff parameter $\alpha$. The $\Upsilon(3S)\pi$ decay channels appear to experience obvious threshold effects which can be understood by the property of the loop integrals. By investigating the $\alpha$-dependence of partial decay widths and ratios between different decay channels, we show that the intermediate $B \ {B}^*$ meson loops are crucial for driving the transitions of $Z_b/Z_b'\to \Upsilon(nS)\pi$ with $n = 1, 2, 3$, and $h_b(mP)\pi$ with $m = 1$ and 2.Comment: 9 pages, 5 figure