Bottom partner B' and Zb production at the LHC

Some new physics models, such as "beautiful mirrors" scenario, predict the existence of the bottom partner $B'$. Considering the constraints from the data for the $Z\rightarrow b\bar{b}$ branching ratio $R_{b}$ and the $FB$ asymmetry $A_{FB}^{b}$ on the relevant free parameters, we calculate the contributions of $B'$ to the cross section $\sigma(Zb)$ and the $Z$ polarization asymmetry $A_{Z}$ for $Zb$ production at the $LHC$. We find that the bottom partner $B'$ can generate significant corrections to $\sigma(Zb)$ and $A_{Z}$, which might be detected in near future.Comment: 15 pages, 5 figures. Version published in Phys. Lett.

One-loop correction to the enhanced curvature perturbation with local-type non-Gaussianity for the formation of primordial black holes

As one of the promising candidates of cold dark matter (DM), primordial black holes (PBHs) were formed due to the collapse of over-densed regions generated by the enhanced curvature perturbations during the radiation-dominated era. The enhanced curvature perturbations are expected to be non-Gaussian in some relevant inflation models and hence the higher-order loop corrections to the curvature power spectrum might be non-negligible as well as altering the abundance of PBHs. In this paper, we calculate the one-loop correction to the curvature power spectrum with local-type non-Gaussianities characterizing by $F_{\mathrm{NL}}$ and $G_{\mathrm{NL}}$ standing for the quadratic and cubic non-Gaussian parameters, respectively. Requiring that the one-loop correction be subdominant, we find a perturbativity condition, namely $|2cAF_{\mathrm{NL}}^2+6AG_{\mathrm{NL}}|\ll 1$, where $c$ is a constant coefficient which can be explicitly calculated in the given model and $A$ denotes the variance of Gaussian part of enhanced curvature perturbation, and such a perturbativity condition can provide a stringent constraint on the relevant inflation models for the formation of PBHs.Comment: 6 pages, 5 figure

α′ Type Ti–Nb–Zr alloys with ultra-low Young's modulus and high strength

Abstractα′ phase based Ti–Nb–Zr alloys with low Young's modulus and high strength were prepared, and their microstructure and mechanical properties were characterized. It was revealed that the lattice expansion by Nb and Zr addition as well as the presence of a few of α″ martensite might be responsible for the low modulus achieved. Ti–15Nb–9Zr alloy, with ultralow modulus of 39GPa and high strength of 850MPa, could be a potential candidate for biomedical applications

Full analysis of the scalar-induced gravitational waves for the curvature perturbation with local-type non-Gaussianities

Primordial black holes (PBHs) are supposed to form through the gravitational collapse of regions with large density fluctuations. The formation of PBHs inevitably leads to the emission of scalar-induced gravitational wave (SIGW) signals, offering a unique opportunity to test the hypothesis of PBHs as a constituent of dark matter (DM). Previous studies have calculated the energy spectrum of SIGWs in local-type non-Gaussian models, primarily considering the contributions from the $F_{\mathrm{NL}}$-order or the $G_{\mathrm{NL}}$-order while neglecting connected diagrams. In this study, we extend the previous work by (i) considering the full contribution of non-Gaussian diagrams up to the $G_{\mathrm{NL}}$-order; (ii) deriving the generic scaling of the SIGW energy spectrum in the infrared region. We derive semi-analytical results applicable to arbitrary primordial power spectra and numerically evaluate the energy spectrum of SIGWs for a log-normal power spectrum.Comment: 21 pages, 2 figure

Zc(3900)Z_c(3900) as a DDˉ∗D\bar{D}^* molecule from the pole counting rule

A comprehensive study on the nature of the $Z_c(3900)$ resonant structure is carried out in this work. By constructing the pertinent effective Lagrangians and considering the important final-state-interaction effects, we first give a unified description to all the relevant experimental data available, including the $J/\psi\pi$ and $\pi\pi$ invariant mass distributions from the $e^+e^-\to J/\psi\pi\pi$ process, the $h_c\pi$ distribution from $e^+e^-\to h_c\pi\pi$ and also the $D\bar D^{*}$ spectrum in the $e^+e^-\to D\bar D^{*}\pi$ process. After fitting the unknown parameters to the previous data, we search the pole in the complex energy plane and find only one pole in the nearby energy region in different Riemann sheets. Therefore we conclude that $Z_c(3900)$ is of $D\bar D^*$ molecular nature, according to the pole counting rule method~[Nucl.~Phys.~A543, 632 (1992); Phys.~Rev.~D 35,~1633 (1987)]. We emphasize that the conclusion based upon the pole counting method is not trivial, since both the $D\bar D^{*}$ contact interactions and the explicit $Z_c$ exchanges are introduced in our analyses and they lead to the same conclusion.Comment: 21 pages, 9 figures. To match the published version in PRD. Additional discussion on the spectral density function is include

(3S,12R,20S,24R)-20,24-Ep­oxy­dammarane-3,12,25-triol

In the title mol­ecule, C30H52O4, the three six-membered rings are in chair conformations, the cyclo­pentane ring is in an envelope form and the tetra­hydro­furan ring has a conformation inter­mediate between half-chair and sofa. In the crystal, mol­ecules are linked by inter­molecular O—H⋯O hydrogen bonds into helical chains along [100]. Two intra­molecular O—H⋯O hydrogen bonds are also present. One C atom of the tetrahydrofuran ring and its attached H atoms are equally disordered over two sets of sites

Four-state rock-paper-scissors games on constrained Newman-Watts networks

We study the cyclic dominance of three species in two-dimensional constrained Newman-Watts networks with a four-state variant of the rock-paper-scissors game. By limiting the maximal connection distance $R_{max}$ in Newman-Watts networks with the long-rang connection probability $p$, we depict more realistically the stochastic interactions among species within ecosystems. When we fix mobility and vary the value of $p$ or $R_{max}$, the Monte Carlo simulations show that the spiral waves grow in size, and the system becomes unstable and biodiversity is lost with increasing $p$ or $R_{max}$. These results are similar to recent results of Reichenbach \textit{et al.} [Nature (London) \textbf{448}, 1046 (2007)], in which they increase the mobility only without including long-range interactions. We compared extinctions with or without long-range connections and computed spatial correlation functions and correlation length. We conclude that long-range connections could improve the mobility of species, drastically changing their crossover to extinction and making the system more unstable.Comment: 6 pages, 7 figure

Impact Of Urbanization On Spatial And Temporal Variation Of Rainfall In Beijing Over The Last 50 Years

Rainfall is one of the key terms involved in many hydrological processes, and it is particularly important in the field of urban hydrology. It is well known that urbanization can have potential impact on precipitation process due to the changes it causes to the ground roughness, thermal-dynamics and many other factors. In this study, the focus is set on the impact on the precipitation patterns in Beijing in term of spatial and temporal variation, from the urbanization over last 50 years in which time the fast and continuous expansion of the city at dramatic scales, the rapid growth of residents population as well as human activities especially building of ground constructions, collectively and inevitably bring changes to the local climatic characteristics of the urbanized areas. This study looks at the two periods according to the speed of urbanization, namely the slow urbanization period of 1957-1980 and the fast urbanization period of 1981-2010. Rainfall data collected from the representative rain gauges across the region is used to analyze the spatial and temporal variation over these two periods. The results show that precipitation in urban areas exhibits the characteristics of higher intensity, shorter duration, with the rainfall mainly concentrated in 60 min or so. Local short-duration rainstorms tend to occur more frequently. Compared with suburban areas, urbanization has significant effect, especially on short-duration precipitation events evidenced by remarkable difference between the coefficients of variation of urban rainfall and those of the suburbs. In addition, for the fast urbanization period, the spatially localized, highly intensive rainfall events are found to be more frequent. Therefore, urbanization of the city has caused increase of the strong convective weather and pressure of flood control drainage, which should be paid more attentions to in city planning