Dark matter production in association with a single top-quark at the LHC in a two-Higgs-doublet model with a pseudoscalar mediator

The sensitivity of the LHC experiments to the associated production of dark matter with a single top is studied in the framework of an extension of the standard model featuring two Higgs doublets and an additional pseudoscalar mediator. It is found that the experimental sensitivity is dominated by the on-shell production of a charged Higgs boson, when this assumes a mass below 1 TeV. Dedicated selections considering one and two lepton final states are developed to assess the coverage in parameter space for this signature at a centre-of-mass energy of 14 TeV assuming an integrated luminosity of 300 fb$^{-1}$. For a pseudoscalar mediator with mass 150 GeV and maximally mixed with the pseudoscalar of the two Higgs doublets, values of $tan\beta$ up to 3 and down to 15 can be excluded at 95% CL, if the $H^{\pm}$ mass is in the range 300 GeV-1 TeV. This novel signature complements the parameter space coverage of the mono-Higgs, mono-Z and $t{\bar t}$+$E_{\mathrm T}^{\mathrm miss}$ signatures considered in previous publications for this model.Comment: 10 pages, 8 figure

Searching for production of dark matter in association with top quarks at the LHC

In the framework of spin-0 $s$-channel dark matter (DM) simplified models, we reassess the sensitivity of future LHC runs to the production of DM in association with top quarks. We consider two different missing transverse energy ($E_T^{\mathrm{miss}}$) signatures, namely production of DM in association with either a $t \bar t$ pair or a top quark and a $W$ boson, where the latter channel has not been the focus of a dedicated analysis prior to this work. Final states with two leptons are studied and a realistic analysis strategy is developed that simultaneously takes into account both channels. Compared to other existing search strategies the proposed combination of $t \bar t + E_T^{\mathrm{miss}}$ and $t W + E_T^{\mathrm{miss}}$ production provides a significantly improved coverage of the parameter space of spin-0 $s$-channel DM simplified models.Comment: 20 pages, 8 figures, 1 table; v2: version accepted by JHE

Searching for dark matter in final states with two jets and missing transverse energy

We reemphasise the usefulness of angular correlations in LHC searches for missing transverse energy ($E_T^{\mathrm{miss}}$) signatures that involve jet $(j)$ pairs with large invariant mass. For the case of mono-jet production via gluon-fusion, we develop a realistic analysis strategy that allows to split the dark matter (DM) signal into distinct one jet-like and two jet-like event samples. By performing state-of-the-art Monte Carlo simulations of both the mono-jet signature and the standard model background, it is shown that the dijet azimuthal angle difference $\Delta \phi_{j_1 j_2}$ in $2 j +E_T^{\mathrm{miss}}$ production provides a powerful discriminant in realistic searches. Employing a shape fit to $\Delta \phi_{j_1 j_2}$, we then determine the LHC reach of the mono-jet channel in the context of spin-0 $s$-channel DM simplified models. The constraints obtained by the proposed $\Delta \phi_{j_1 j_2}$ shape fit turn out to be significantly more stringent than those that derive from standard $E_T^{\mathrm{miss}}$ shape analyses.Comment: 16 pages, 6 figures, 1 table; v3: one typographical error correcte

Single-top final states as a probe of top-flavoured dark matter models at the LHC

Models incorporating flavoured dark matter provide an elegant solution to the dark matter problem, evading the tight LHC and direct direction constraints on simple WIMP models. In Dark Minimal Flavour Violation, a simple framework of flavoured dark matter with new sources of flavour violation, the constraints from thermal freeze-out, direct detection experiments, and flavour physics create well-defined benchmark scenarios for these models. We study the LHC phenomenology of four such scenarios, focusing on final states where a single top quark is produced accompanied by no jets, one jet from the fragmentation of light quarks or a $b$-tagged jet. For each of these signatures we develop a realistic LHC analysis, and we show that the proposed analyses would increase the parameter space coverage for the four benchmarks, compared to existing flavour-conserving LHC analyses. Finally we show the projected discovery potential of the considered signatures for the full LHC statistics at 14 TeV, and for the High Luminosity LHC.Comment: 25 pages, 14 figures, 2 tables. v2: clarifying comments and few references added, matches published versio

Particle Flow with a Hybrid Segmented Crystal and Fiber Dual-Readout Calorimeter

In the reconstruction of physics events at future e$^+$e$^-$ colliders the calorimeter design has a crucial role in the overall detector performance. The reconstruction of events with many jets in their final state sets stringent requirements on the jet energy and angular resolutions. The energy resolution for jets with energy of about 45 GeV is required to be at the 4-5\% level to enable an efficient separation of the W and Z boson invariant masses. We demonstrate in this paper how such a performance can be achieved by exploiting a particle flow algorithm tailored for a hybrid dual-readout calorimeter made of segmented crystals and fibers. The excellent energy resolution and linearity of such calorimeter for both photons and neutral hadrons ($3\%/\sqrt{E}$ and $26\%/\sqrt{E}$, respectively), inherent to the homogeneous crystals and dual-readout technological choices, provides a powerful handle for the development of a new approach for particle identification and jet reconstruction. While the dual-readout particle flow algorithm (DR-PFA) presented in this paper is at its early stage of development, it already demonstrates the potential of a hybrid dual-readout calorimeter for jet reconstruction by improving the jet energy resolution with respect to a calorimeter-only reconstruction from 6.0\% to about 4.5\% for 45 GeV jets

Investigation of ATON (kaifeng) Company :From crisis to vitality

福建亚通新材料科技股份有限公司是家专业从事高分子材料管道系统研究开发与制造生产的企业。2010年初，其全资子公司亚通塑胶（开封）有限公司（下称亚通开封公司）因突发事件陷入危机。新任子公司总经理面临危机的考验，采取适当措施，带领企业走出危机实现生机。 本文是在领导力理论、战略管理理论及市场营销理论的框架下，针对对亚通开封公司的问题进行分析和研究，在调查和研究企业实体和相关理论的基础上，采用宏观和微观、定性和定量相结合的方法，具体研究了企业在一年内发生的从被动到主动、从亏损到盈利、从人心涣散到充满活力的实际经验，用实证研究反映企业从危机四伏到焕发新机的转变。 本文首先阐述了领导力对亚通开封公司...Fujian ATON Advanced Materials Science and Technology Co., Ltd (company) is a high technology enterprise specialized in manufacturing, research and development of high molecular materials and relative products. ATON plastics (kaifeng) Co., Ltd is a subsidiary of parent company founded in Kaifeng. In early of 2010, the GM of kaifeng company established a new company as a competitor of ATON, took a...学位：工商管理硕士院系专业：管理学院工商管理教育中心（MBA中心）_工商管理硕士(MBA)学号：1792008115112

Constraining Dark Matter in the MSSM at the LHC

In the event that R-Parity conserving supersymmetry (SUSY) is discovered at the LHC, a key issue which will need to be addressed will be the consistency of that signal with astrophysical and non-accelerator constraints on SUSY Dark Matter. This issue is studied for the SPA benchmark model based on measurements of end-points and thresholds in the invariant mass spectra of various combinations of leptons and jets. These measurements are used to constrain the soft SUSY breaking parameters at the electroweak scale in a general MSSM model. Based on these constraints, we assess the accuracy with which the Dark Matter relic density can be measured.Comment: 21 pages, 12 figure

A hybrid method for determining particle masses at the Large Hadron Collider with fully identified cascade decays

A new technique for improving the precision of measurements of SUSY particle masses at the LHC is introduced. The technique involves kinematic fitting of events with two fully identified decay chains. We incorporate both event ETmiss constraints and independent constraints provided by kinematic end-points in experiment invariant mass distributions of SUSY decay products. Incorporation of the event specific information maximises the information used in the fit and is shown to reduce the mass measurement uncertainites by ~30% compared to conventional fitting of experiment end-point constraints for the SPS1a benchmark model.Comment: 10 pages, 2 .eps figures, JHEP3 styl