arXiv subjects

Li-Ping Sun

Publications and source records attributed to Li-Ping Sun.

8 recordsLinked to original sources

arXiv2024

$B_c$, $B_s$ and $D_s$ production at lepton-hadron colliders

Within the framework of nonrelativistic quantum chromodynamics, this study examines the electroproduction processes $e+p\to e+B_c+\overline{c}+b$, $e+p\to e+B_s+\overline{s}+b$, and $e+p\to e+D_s+\overline{c}+s$ at lepton-hadron colliders. The differential cross sections in $\cos\theta$ and $p_T^2$ at HERA are presented. The results indicate that the production of $B_c$ is feasible at the EIC, whereas it is not at HERA. The cross sections for $B_s$ and $D_s$ are notably significant at HERA, yet they exhibit sensitivity to variations in quark mass and renormalization scale.

hep-ph↗

arXiv2014

Resolving the puzzling decay patterns of charged $Z_c$ and $Z_b$ states

We investigate the ratio of the branching fractions of the molecular candidates decaying into the ground and radially excited states within the quark interchange model. Our numerical results suggest that these molecular candidates are more likely to decay into the radially excited states than into ground states. Especially, the ratio $\Gamma[Z_c(4430)\to \pi\psi(2S)]$/$\Gamma[Z_c(4430)\to \pi J/\psi]\sim 9.8$ is close to the experimental measurement, which supports the interpretation of $Z_c(4430)$ as the $\bar{D}D^*(2S)$ molecular state. The ratios of the branching fractions of $Z_b(10610)$ and $Z_b(10650)$ to $\pi\Upsilon(2S, 3S)$ and $\pi\Upsilon(1S)$ agrees very well with Belle's measurement. We also predict the similar ratios for $Z_c(3900)$, $Z_c(4020)$, $R_{Z_c(3900)}$$\approx$1.3 and $R_{Z_c(4020)}$$\approx$$4.7$. Hopefully the $\pi\psi(2S)$ mode, and ratios $R_{Z_c(3900)}$ and $R_{Z_c(4020)}$ will be measured by the BESIII and Belle collaborations in the near future, which shall be very helpful to understand the underlying dynamics of these exotic states.

hep-ph↗

arXiv2014

Impact of $J/\psi$ pair production at the LHC and predictions in nonrelativistic QCD

For $J/\psi$ pair production at hadron colliders, we present the full next-to-leading order (NLO) calculations with the color-singlet channel in nonrelativistic QCD. We find that the NLO result can reasonably well describe the LHCb measured cross section, but exhibits very different behaviors from the CMS data in the transverse momentum distribution and mass distribution of $J/\psi$ pair. Moreover, by adding contributions of gluon fragmentation and quark fragmentation, which occur at even higher order in $\alpha_s$, it is still unable to reduce the big differences. In particular, the observed flat distribution in the large invariant mass region is hard to explain. New processes or mechanisms are needed to understand the CMS data for $J/\psi$ pair production.

hep-ph↗

arXiv2012

$J/\psi$ Pair Production at the Tevatron with $\sqrt{s}=1.96~\mathrm{TeV}

We revisit the $J/\psi$ pair production issue at the Fermilab Tevatron Run II with the center-of-mass energy $\sqrt{s}=1.96 \mathrm{TeV}$. Both color-singlet and -octet production mechanisms are considered. Our result shows that the transverse momentum($p_T$) scaling behaviors of double $J/\psi$ differential cross sections in color-singlet and -octet deviate distinctively from each other while $p_T$ is larger than $8 \mathrm{GeV}$, and with the luminosity of ${5 \mathrm{fb^{-1}}}$ the $J/\psi$ pair events from color-singlet scheme are substantially measurable in Tevatron experiments, even with certain lower transverse momentum cut. Hence the Tevatron is still possibly a platform to check the heavy quarkonium production mechanism.

hep-ph↗

arXiv2011

The NLO QCD Corrections to $B_c$ Meson Production in $Z^0$ Decays

The decay width of $Z^0$ to $B_c$ meson is evaluated at the next-to-leading order(NLO) accuracy in strong interaction. Numerical calculation shows that the NLO correction to this process is remarkable. The quantum chromodynamics(QCD)renormalization scale dependence of the results is obviously depressed, and hence the uncertainties lying in the leading order calculation are reduced.

hep-ph↗

arXiv2011

W Boson Inclusive Decays to Quarkonium at the LHC

In this paper, the production rates of quarkonia eta_c, J/psi, eta_b, Upsilon, B_c and B_c^* through W boson decay at the LHC are calculated, at the leading order in both the QCD coupling constant and in v, the typical velocity of the heavy quark inside of mesons. It shows that a sizable number of quarkonia from W boson decay will be produced at the LHC. Comparison with the predictions by using quark fragmentation mechanism is also discussed. Results show that, for the charmonium production through W decay, the difference between predictions by the fragmentation mechanism and complete leading order calculation is around 3%, and it is insensitive to the uncertainties of theoretical parameters; however, for the bottomonium and B_c^(*) productions, the difference cannot be ignored as the fragmentation mechanism is less applicable here due to the relatively large ratio mb/mw.

hep-ph↗

arXiv2010

The Next-to-Leading Order Corrections to Top Quark Decays to Heavy Quarkonia

The decay widths of top quark to S-wave $b\bar{c}$ and $b\bar{b}$ bound states are evaluated at the next-to-leading(NLO) accuracy in strong interaction. Numerical calculation shows that the NLO corrections to these processes are remarkable. The quantum chromodynamics(QCD) renormalization scale dependence of the results are obviously depressed, and hence the uncertainties lying in the leading order calculation are reduced.

hep-ph↗

arXiv2009

Testing Charmonium Production Mechanism via Polarized $J/\psi$ Pair Production at the LHC

At present the color-octet mechanism is still an important and debatable part in the non-relativistic QCD(NRQCD). We find in this work that the polarized double charmonium production at the LHC may pose a stringent test on the charmonium production mechanism. Result shows that the transverse momentum($p_T$) scaling behaviors of double $J/\psi$ differential cross sections in color-singlet and -octet production mechanisms deviate distinctively from each other while $p_T$ is larger than 7 GeV. In color-octet mechanism, the two $J/\psi$s in one pair are mostly transversely polarized when $p_T\gg 2 m_c$, as expected from the fragmentation limit point of view. In color-singlet mechanism, there is about one half of the charmonium pairs with at least one $J/\psi$ being longitudinally polarized at moderate transverse momentum. The energy dependence of the polarized $J/\psi$ pair production is found to be weak, and this process is found to be experimentally attainable in the early phase of the LHC operation.

hep-ph↗