Related papers: Hidden-charm Pentaquark Production at $e^+e^-$ Col…
We develop the formalism for production of a fully heavy tetraquark and apply it to the calculation of $pp\to T_{4c}+X$ cross-sections. We demonstrate that the production cross-section of a fully heavy tetraquark, even if it is a…
We present the first predictions for sub-threshold open charm and charmonium production in nuclear collisions. The production mechanism is driven by multi-step scatterings of nucleons and their resonance states, accumulating sufficient…
In the present work, we investigate the molecular properties of the hidden charm pentaquark states $P_c$ and $P_{cs}$ with a coupled channel framework that combines heavy quark spin symmetry and the local hidden gauge formalism. By solving…
We have recently studied hidden-charm pentaquarks, $c\bar c qqq$, using dynamical correlations between the heavy quarks arising from the Coulomb-like nature of the short-range interaction. A pattern was obtained that compares well with the…
The processes of open and hidden charm production in $NN$ collisions and of open charm production in $\gamma N$ collisions are studied. The near-threshold cross section is predicted and polarization phenomena are calculated in frame of an…
We report the observation of prompt J/psi via double ccbar production from the e+e- continuum. In this process one ccbar pair fragments into a J/psi meson while the remaining pair either produces a bound charmonium state or fragments into…
We provide a simple explanation for the observed hidden-charm pentaquarks as bound states in Born-Oppenheimer potentials. We identify $P_{c\bar{c}}(4312)^+$, $P_{c\bar{c}}(4440)^+$, and $P_{c\bar{c}}(4457)^+$ as heavy-quark spin states in a…
Assuming that the $P_c(4312)^+$ is a $I(J^P)=\frac12(\frac32^-)$ compact pentaquark, we study the mass spectrum of its S-wave hidden-charm partner states in a color-magnetic interaction model. Combining the information from their decays…
Motivated by the ATLAS and CMS announcements of the excesses of di-photon events, we discuss the production and decay processes of di-photon resonance at future $e^+e^-$ colliders. We assume that the excess of the di-photon events at the…
We discuss possibilities of identifying open charm effects in direct production processes, and propose that direct evidence for the open charm effects can be found in $e^+ e^-\to J/\psi\pi^0$. A unique feature with this process is that the…
We consider J/psi photoproduction in e+ e- as well as linear photon colliders. We find that the process is dominated by the resolved photon channel. Both the once-resolved and twice-resolved cross-sections are sensitive to (different…
TGD predicts the existence of color octet excitations of ordinary leptons forming 'leptohadrons' as their color singlet bound states. There is some evidence on the existence of leptohadrons: the production of anomalous $e^+e^-$ pairs in…
We estimate the differential and total cross sections for both the photoproduction of vector D*-meson and its yield in deep inelastic scattering at the HERA collider in the framework of model motivated by perturbative calculations in QCD.…
Structure and production of doubly charmed tetraquarks T_cc (cc ubar dbar) are studied from the viewpoint of color configurations. Based on the diquark correlation, the tetraquark T_cc with I(JP)=0(1+) is considered to be stable against…
A search for pair-produced leptoquarks is performed using e+e- collision events collected by the OPAL detector at LEP at centre-of-mass energies between 189 and 209 GeV. The data sample corresponds to a total integrated luminosity of 596…
We report measurements of charmed hadron production from hadronic ($D^{0}\rightarrow K\pi$) and semileptonic ($\mu$ and $e$) decays in 200 GeV Au+Au collisions at RHIC. Analysis of the spectra indicates that charmed hadrons have a different…
The strange pentaquarks with hidden heavy quark pair ($q^3c\bar c$ and $q^3b \bar b$) are investigated by the coupled-channel quark cluster model. Two types of the $q^3$ color-octet configurations are found to provide the attraction, which…
As a test of the color-singlet mechanism of the nonrelativistic QCD (NRQCD) factorization approach, we consider the exclusive two-quarkonium productions in electron-positron annihilation e+ e- -> eta_c + gamma and e+ e- -> J/psi + J/psi at…
Recent results on production and decays of polarized top quarks are reviewed. Top quark pair production in $e^+e^-$ annihilation is considered near energy threshold. For longitudinally polarized electrons the produced top quarks and…
We apply the newly developed NRQCD factorization formula to analyze the exclusive production of the fully-charmed tetraquark $T_{4c}$ plus a hard photon at $B$ factory. For simplicity, in this work we have concentrated on the associated…