Production rates for hadrons, pentaquarks Θ+\Theta ^+ and Θ∗++\Theta ^{*++}, and di-baryon (ΩΩ)0+(\Omega\Omega)_{0^{+}} in relativistic heavy ion collisions by a quark combination model

The hadron production in relativistic heavy ion collisions is well described by the quark combination model. The mixed ratios for various hadrons and the transverse momentum spectra for long-life hadrons are predicted and agree with recent RHIC data. The production rates for the pentaquarks $\Theta ^+$, $\Theta ^{*++}$ and the di-baryon $(\Omega\Omega)_{0^{+}}$ are estimated, neglecting the effect from the transition amplitude for constituent quarks to form an exotic state.Comment: The difference between our model and other combination models is clarified. The scaled transverse momentum spectra for pions, kaons and protoms at both 130 AGeV and 200 AGeV are given, replacing the previous results in transverse momentum spectr

Searching for long-lived particles beyond the Standard Model at the Large Hadron Collider

Particles beyond the Standard Model (SM) can generically have lifetimes that are long compared to SM particles at the weak scale. When produced at experiments such as the Large Hadron Collider (LHC) at CERN, these long-lived particles (LLPs) can decay far from the interaction vertex of the primary proton–proton collision. Such LLP signatures are distinct from those of promptly decaying particles that are targeted by the majority of searches for new physics at the LHC, often requiring customized techniques to identify, for example, significantly displaced decay vertices, tracks with atypical properties, and short track segments. Given their non-standard nature, a comprehensive overview of LLP signatures at the LHC is beneficial to ensure that possible avenues of the discovery of new physics are not overlooked. Here we report on the joint work of a community of theorists and experimentalists with the ATLAS, CMS, and LHCb experiments—as well as those working on dedicated experiments such as MoEDAL, milliQan, MATHUSLA, CODEX-b, and FASER—to survey the current state of LLP searches at the LHC, and to chart a path for the development of LLP searches into the future, both in the upcoming Run 3 and at the high-luminosity LHC. The work is organized around the current and future potential capabilities of LHC experiments to generally discover new LLPs, and takes a signature-based approach to surveying classes of models that give rise to LLPs rather than emphasizing any particular theory motivation. We develop a set of simplified models; assess the coverage of current searches; document known, often unexpected backgrounds; explore the capabilities of proposed detector upgrades; provide recommendations for the presentation of search results; and look towards the newest frontiers, namely high-multiplicity 'dark showers', highlighting opportunities for expanding the LHC reach for these signals

Effects of Panax notoginseng saponins on proliferation and differentiation of rat embryonic cortical neural stem cells

AbstractBackgroundWe aimed to study the effect of Panax notoginseng saponins (PNS) on the proliferation, differentiation, self-renewal, and expressions of basic fibroblast growth factor (bFGF) and brain-derived neurotrophic factor (BDNF) in rat embryonic neural stem cells (NSCs).MethodsCortical stem cells were isolated from rat embryos on Embryonic Day 17 (E17) and identified by nestin expression. Subsequently, primary culture, subculturing, and single cell cloning were performed on the cells. After the first cell passage (P1), the cells were resuspended and divided into a control group and a treatment group. Control cells were cultured in serum-free basal culture medium with B27 and dulbecco's modified eagle medium (DMEM)/F12. The same medium supplemented with PNS (100 μg/mL) was used to culture cells in the treatment group. Both groups were incubated at 37°C in a 5% CO2 incubator. Immunocytochemistry was performed 4 days after incubation.ResultsPrimary, P1, and P2 cells in the treatment group formed neurospheres, as did single cell clones of the P1 cells in this group. After being cultured for 4 days, the number of nestin-, proliferating cell nuclear antigen (PCNA)-, Tuj-1-, neurofilament (NF)-, vimentin-, glial fibrillary acidic protein (GFAP)-, bFGF-, and BDNF-positive cells significantly increased in the treatment group in comparison to the control group. All positively stained cells could form clear clusters.ConclusionPNS can promote rat embryonic cortical NSC survival, self-renewal, proliferation, and differentiation through neurotrophic factors by autocrine or paracrine signaling