Towards the fate of natural composite Higgs model through single t′t^\prime search at the 8 TeV LHC

We analyze the observational potential of single $t'$ production in both the $t^\prime \rightarrow bW$ and $t^\prime \rightarrow th$ decay channels at 8 TeV LHC using an integrated luminosity of 25 $\text{fb}^{-1}$. Our analysis is based on a simplified model with minimal coset $SO(5)/SO(4)$ in which the $t'$ is a singlet of the unbroken SO(4). The single $t'$ production, as a consequence of electroweak symmetry breaking, is less kinematically suppressed, associated with a light forward jet and has boosted decay products at the 8 TeV LHC. Therefore it provides the most promising channel in searching for a heavy $t'$. We have exploited the above kinematical features and used the jet substructure method to reconstruct the boosted Higgs in $th$ decay channel. It is shown that a strong constraint on the $t^\prime bW$ coupling ($g_{t^\prime bW}/g_{tbW,SM} < 0.2 \sim 0.3$) at the 95% C. L. can be obtained for $m_{t'} \subset (700, 1000)$ GeV.Comment: 22 pages, 8 figures, 5 tables, refs added in v

Probing the CP-even Higgs Sector via H3→H2H1H_3\to H_2H_1 in the Natural NMSSM

After the discovery of a Standard Model (SM) like Higgs boson, naturalness strongly favors the next to the Minimal Supersymmetric SM (NMSSM). In this letter, we point out that the most natural NMSSM predicts the following CP-even Higgs $H_i$ sector: (A) $H_2$ is the SM-like Higgs boson with mass pushed-upward by a lighter $H_1$ with mass overwhelmingly within $[m_{H_2}/2,m_{H_2}]$; (B) $m_{H_3}\simeq 2\mu/\sin2\beta\gtrsim300$ GeV; (C) $H_3$ has a significant coupling to top quarks and can decay to $H_1H_2$ with a large branching ratio. Using jet substructure we show that all the three Higgs bosons can be discovered via $gg\to H_3 \to H_1H_2\to b\bar b \ell\nu jj$ at the 14 TeV LHC. Especially, the LEP-LHC scenario with $H_1\simeq98$ GeV has a very good discovery potential.Comment: 5 pages, 2 figures. Some typos corrected and reference adde

Type-III two Higgs doublet model plus a pseudoscalar confronted with h→μτh\rightarrow\mu\tau, muon g−2g-2 and dark matter

In this work, we introduce an extra singlet pseudoscalar into the Type-III two Higgs doublet model (2HDM) which is supposed to solve a series of problems in the modern particle-cosmology. With existence of a light pseudoscalar, the $h\rightarrow\mu\tau$ excess measured at CMS and as well as the $(g-2)_{\mu}$ anomaly could be simultaneously explained within certain parameter spaces that can also tolerate the data on the flavor-violating processes $\tau\rightarrow\mu\gamma$ and Higgs decay gained at LHC. Within the same parameter spaces, the DM relic abundance is well accounted. Moreover, the recently observed Galactic Center gamma ray excess(GCE) is proposed to realize through dark matter(DM) pair annihilations, and in this work, the scenario of the annihilation being mediated by the pseudoscalar is also addressed.Comment: 14 pages, 8 figures, version to appear in NP

Two component dark matter with multi-Higgs portals

With the assistance of two extra groups, i.e., an extra hidden gauge group $SU(2)_D$ and a global $U(1)$ group, we propose a two component dark matter (DM) model. After the symmetry $SU(2)_D\times U(1)$ being broken, we obtain both the vector and scalar DM candidates. The two DM candidates communicate with the standard model (SM) via three Higgs as multi-Higgs portals. The three Higgs are mixing states of the SM Higgs, the Higgs of the hidden sector and real part of a supplement complex scalar singlet. We study relic density and direct detection of DM in three scenarios. The resonance behaviors and interplay between the two component DM candidates are represented through investigating of the relic density in the parameter spaces of the two DMs masses. The electroweak precision parameters constrains the two Higgs portals couplings ($\lambda_m$ and $\delta_2$). The relevant vacuum stability and naturalness problem in the parameter space of $\lambda_m$ and $\delta_2$ are studied as well. The model could alleviate these two problems in some parameter spaces under the constraints of electroweak precision observables and Higgs indirect search.Comment: 27 pages, 16 figures. Version accepted for publication in JHE

Electron Flavored Dark Matter

In this paper we investigate the phenomenology of the electron flavored Dirac dark matter with two types of portal interactions. We analyze constraints from the electron magnetic moment anomaly, LHC searches of singly charged scalar, dark matter relic abundance as well as direct and indirect detections. Our study shows that the available parameter space is quite constrained, but there are parameter space that is compatible with the current data. We further show that the DAMPE cosmic ray electron excess, which indicates cosmic ray excess at around 1.5 TeV, can be interpreted as the annihilation of dark matter into electron positron pairs in this model.Comment: 6 pages, 5 figure

Genetic learning particle swarm optimization

Social learning in particle swarm optimization (PSO) helps collective efficiency, whereas individual reproduction in genetic algorithm (GA) facilitates global effectiveness. This observation recently leads to hybridizing PSO with GA for performance enhancement. However, existing work uses a mechanistic parallel superposition and research has shown that construction of superior exemplars in PSO is more effective. Hence, this paper first develops a new framework so as to organically hybridize PSO with another optimization technique for “learning.” This leads to a generalized “learning PSO” paradigm, the *L-PSO. The paradigm is composed of two cascading layers, the first for exemplar generation and the second for particle updates as per a normal PSO algorithm. Using genetic evolution to breed promising exemplars for PSO, a specific novel *L-PSO algorithm is proposed in the paper, termed genetic learning PSO (GL-PSO). In particular, genetic operators are used to generate exemplars from which particles learn and, in turn, historical search information of particles provides guidance to the evolution of the exemplars. By performing crossover, mutation, and selection on the historical information of particles, the constructed exemplars are not only well diversified, but also high qualified. Under such guidance, the global search ability and search efficiency of PSO are both enhanced. The proposed GL-PSO is tested on 42 benchmark functions widely adopted in the literature. Experimental results verify the effectiveness, efficiency, robustness, and scalability of the GL-PSO

A WENO Algorithm of the Temperature and Ionization Profiles around a Point Source

We develop a numerical solver for radiative transfer problems based on the weighted essentially nonoscillatory (WENO) scheme modified with anti-diffusive flux corrections, in order to solve the temperature and ionization profiles around a point source of photons in the reionization epoch. Algorithms for such simulation must be able to handle the following two features: 1. the sharp profiles of ionization and temperature at the ionizing front (I-front) and the heating front (T-front), and 2. the fraction of neutral hydrogen within the ionized sphere is extremely small due to the stiffness of the rate equations of atom processes. The WENO scheme can properly handle these two features, as it has been shown to have high order of accuracy and good convergence in capturing discontinuities and complicated structures in fluid as well as to be significantly superior over piecewise smooth solutions containing discontinuities. With this algorithm, we show the time-dependence of the preheated shell around a UV photon source. In the first stage the I-front and T-front are coincident, and propagate with almost the speed of light. In later stage, when the frequency spectrum of UV photons is hardened, the speeds of propagation of the ionizing and heating fronts are both significantly less than the speed of light, and the heating front is always beyond the ionizing front. In the spherical shell between the I- and T-fronts, the IGM is heated, while atoms keep almost neutral. The time scale of the preheated shell evolution is dependent on the intensity of the photon source. We also find that the details of the pre-heated shell and the distribution of neutral hydrogen remained in the ionized sphere are actually sensitive to the parameters used. The WENO algorithm can provide stable and robust solutions to study these details.Comment: 24 pages, 7 figures, accepted in New Astronom

Poly[aqua­[μ3-4-carb­oxy-2-(pyridin-4-yl)-1H-imidazole-5-carboxyl­ato-κ5 N 1,O 5:N 3,O 4:N 2]nickel(II)]

The water-coordinated Ni2+ cation in the title compound, [Ni(C10H5N3O4)(H2O)]n, assumes an octa­hedral NiN3O3 coord­ination mode and is N,O-chelated by two deprotonated 2-(pyridin-4-yl)-1H-imidazole-4,5-dicarb­oxy­lic acid (HPyImDC2−) ligands, forming a layer structure extending in the bc plane. The chains are arranged along the b-axis direction, forming a layer structure extending in the bc plane. O—H⋯O hydrogen bonding between the layers results in the formation of a three-dimensional supra­molecular framework. The structure is isotypic with the Zn analogue [Li et al. (2009). Cryst. Growth Des. 6, 3423–3431]