Spin correlations in polarizations of P-wave charmonia χcJ\chi_{cJ} and impact on J/ψJ/\psi polarization

Based on a general form of the effective vertex functions for the decays of P-wave charmonia \chicj, angular distribution formulas for the subsequent decays \chicj\rightarrow \jpsi \gamma and \jpsi \to \mu^+\mu^- are derived. The formulas are the same as those obtained in a different approach in the literature. Our formulas are expressed in a more general form, including parity violation effects and the full angular dependence of \jpsi and muon in the cascade decay \chicj\to\jpsi\gamma\to\mu^+\mu^-\gamma. The \chicj polarization observables are expressed in terms of rational functions of the spin density matrix elements of \chicj production. Generalized rotation-invariant relations for arbitrary integer-spin particles are also derived and their expressions in terms of observable angular distribution parameters are given in the $\chi_{c1}$ and $\chi_{c2}$. To complement our previous direct-\jpsi polarization result, we also discuss the impact on the observable prompt-\jpsi polarization. As an illustrative application of our angular distribution formulas, we present the angular distributions in terms of the tree-level spin density matrix elements of $\chi_{c1}$ and $\chi_{c2}$ production in several different frames at the Large Hadron Collider. Moreover, a reweighting method is also proposed to determine the entire set of the production spin density matrix elements of the $\chi_{c2}$, some of which disappear or are suppressed for vanishing higher-order multipole effects making the complete extraction difficult experimentally.Comment: Version published in PRD, 23 pages, 18 figure

ηc\eta_c production at LHC and indications on the understanding of J/ψJ/\psi production

We present a complete evaluation for the prompt $\eta_c$ production at the LHC at next-to-leading order in $\alpha_s$ in nonrelativistic QCD. By assuming heavy quark spin symmetry, the recently observed $\eta_c$ production data by LHCb results in a very strong constraint on the upper bound of the color-octet long distance matrix element $1S0$ of $J/\psi$. We find this upper bound is consistent with our previous study of the $J/\psi$ yield and polarization and can give good descriptions for the measurements, but inconsistent with some other theoretical estimates. This may provide important information for understanding the nonrelativistic QCD factorization formulism.Comment: 5 pages, 2 figures, published version in PR

To Enhance the Fire Resistance Performance of High-Speed Steel Roller Door with Water Film System

The structure of high-speed roller door with water film has improved in this study. The flameproof water film system is equipped with a water circulating device to reduce the water consumption of water film system. The water film is generated at the roller box of the high-speed roller door in this study. The heating test is done with the full-scale heating furnace. Both cases of the water film on unexposed surface and water film on exposed surface passed the fire resistance test based on ISO 834, proving that the high-speed roller door with water film system has 120A fire resistance period. The main findings indicate that the water film on exposed surface shows that as the amount of water film evaporated by high temperature inside the furnace must be greater than the evaporation capacity of water film on unexposed surface, the required water supply is 660 L more than the water film on unexposed surface

Causal Evidence for the Role of Specific GABAergic Interneuron Types in Entorhinal Recruitment of Dentate Granule Cells

The dentate gyrus (DG) is the primary gate of the hippocampus and controls information flow from the cortex to the hippocampus proper. To maintain normal function, granule cells (GCs), the principal neurons in the DG, receive fine- tuned inhibition from local-circuit GABAergic inhibitory interneurons (INs). Abnormalities of GABAergic circuits in the DG are associated with several brain disorders, including epilepsy, autism, schizophrenia, and Alzheimer disease. Therefore, understanding the network mechanisms of inhibitory control of GCs is of functional and pathophysiological importance. GABAergic inhibitory INs are heterogeneous, but it is unclear how individual subtypes contribute to GC activity. Using cell-type-specific optogenetic perturbation, we investigated whether and how two major IN populations defined by parvalbumin (PV) and somatostatin (SST) expression, regulate GC input transformations. We showed that PV-expressing (PV+) INs, and not SST- expressing (SST+) INs, primarily suppress GC responses to single cortical stimulation. In addition, these two IN classes differentially regulate GC responses to θ and γ frequency inputs from the cortex. Notably, PV+ INs specifically control the onset of the spike series, whereas SST+ INs preferentially regulate the later spikes in the series. Together, PV+ and SST+ GABAergic INs engage differentially in GC input-output transformations in response to various activity patterns

NLO results with operator mixing for fully heavy tetraquarks in QCD sum rules

We study the mass spectra of $\overline{Q}Q\overline{Q}Q (Q = c, b)$ systems in QCD sum rules with the complete next-to-leading order (NLO) contribution to the pertabative QCD part of the correlation functions. Instead of meson-meson or diquark-diquark currents, we use diagonalized currents under operator renormalization. Numerical results show that the NLO corrections are very important for the $\overline{Q}Q\overline{Q}Q$ system, because they not only give significant contributions but also reduce parameter dependence and makes Borel platform more distinct, especially for the $\overline{b}b\overline{b}b$ in the $\overline{MS}$ scheme. We find that the operator mixing induced by NLO corrections is crucial to understand the color structure of the states. We use currents that have good perturbative convergence in our phenomenological analysis. We get three $J^{PC} = 0^{++}$ states, with masses $6.35^{+0.20}_{−0.17}$ GeV, $6.56^{+0.18}_{−0.20}$ GeV and $6.95^{+0.21}_{−0.31}$ GeV, respectively. The first two seem to agree with the broad structure around 6.2∼6.8 GeV measured by the LHCb collaboration in the $J/\psi J/\psi$ spectrum, and the third seems to agree with the narrow resonance X(6900). For the 2$^{++}$ states we find one with mass $7.03^{+0.22}_{−0.26}$ GeV, which is also close to that of X(6900), and another one around 7.3 GeV but with larger uncertainties

NLO results with operator mixing for fully heavy tetraquarks in QCD sum rules

We study the mass spectra of $\overline{Q}Q\overline{Q}Q (Q = c, b)$ systems in QCD sum rules with the complete next-to-leading order (NLO) contribution to the perturbative QCD part of the correlation functions. Instead of meson-meson or diquark-antidiquark currents, we use diagonalized currents under operator renormalization. We find that differing from conventional mesons $\overline{q}q$ and baryons $qqq$, a unique feature of the multiquark systems like $\overline{Q}Q\overline{Q}Q$ is the operator mixing or color configuration mixing induced by NLO corrections, which is crucial to understand the color structure of the states. Our numerical results show that the NLO corrections are very important for the $\overline{Q}Q\overline{Q}Q$ system, because they not only give significant contributions but also reduce the scheme and scale dependence and make Borel platform more distinct, especially for the $\overline{b}b\overline{b}b$ in the $\overline{MS}$ scheme. We use currents that have good perturbation convergence in our phenomenological analysis. With the $\overline{MS}$ scheme, we get three $J^{PC} = 0^{++}$ states, with masses $6.35^{+0.20}_{−0.17}$ GeV, $6.56^{+0.18}_{−0.20}$ GeV and $6.95^{+0.21}_{−0.31}$ GeV, respectively. The first two seem to agree with the broad structure around 6.2 ~ 6.8 GeV measured by the LHCb collaboration in the $J/\psi J/\psi$ spectrum, and the third seems to agree with the narrow resonance X(6900). For the 2$^{++}$ states we find one with mass $7.03^{+0.22}_{−0.26}$ GeV, which is also close to that of X(6900), and another one around $7.25^{+0.21}_{−0.35}$ GeV, which has good scale dependence but slightly large scheme dependence