Seeking for sterile neutrinos with displaced leptons at the LHC

We study the signal of long-lived sterile neutrino at the LHC produced through the decay of the $W$ boson. It decays into charged lepton and jets. The characteristic signature is a hard prompt lepton and a lepton from the displaced decay of the sterile neutrino, which leads to a bundle of displaced tracks with large transverse impact parameter. Different from other studies, we neither reconstruct the displaced vertex nor place requirement on its invariant mass to maintain sensitivity for low sterile neutrino masses. Instead, we focus on the displaced track from the lepton. A difficulty for low mass sterile neutrino study is that the displaced lepton is usually \textit{non-isolated}. Therefore, leptons from heavy flavor quark is the major source of background. We closely follow a search for displaced electron plus muon search at CMS and study their control regions, which is related to our signal regions, in great detail to develop a robust estimation of the background for our signals. After further optimization on the signal limiting the number of jets, low $H_T$ and large lepton displacement $d_0$ to suppress SM background, we reach an exclusion sensitivity of about $10^{-8}$ ($10^{-5}$) for the mixing angle square at 10 (2) GeV sterile neutrino mass respectively. The strategy we propose can cover the light sterile masses complimentary to beam dump and forward detector experiments.Comment: 22 pages, 6 figures, 1 table; v2: matched to Journal version

3-(3,4-Dimeth­oxy­phen­yl)-4-(2-meth­oxy­anilino)furan-2(5H)-one

In the title compound, C19H19NO5, the furan­one unit makes a dihedral angle of 30.93 (6)° with the benzene ring and a dihedral angle of 9.51 (6)° with the aniline ring. In the crystal, inter­molecular C—H⋯O hydrogen bonds and C—H⋯π contacts link the mol­ecules into sheets. A weak intramolecular hydrogen bond is also observed

Preparation and Characterization of a Standardized Anticonvulsant Ginseng Rb Extract from Panax quinquefolius L.

A ginseng Rb extract (GRbE) containing three major ingredients of ginsenoside Rb1 (G-Rb1), ginsenoside Rb3 (G-Rb3) and ginsenoside Rd (G-Rd) has been shown to have anticonvulsant and neuroprotective activity. As such, sufficient characterization and standardization of this active GRbE are demanded to facilitate an ongoing preclinical investigation on its potential for the treatment of epilepsy. In the investigation, the methods for generating the active GRbE and isolating G-Rb1, G-Rb3, and G-Rd in large scale from Panax quinquefolius are described. The chemical profile of GRbE was characterized by identifying the structure of the individual ingredients using NMR, and the concentration of individual ingredients was determined using HPLC. This study demonstrates the application of the established methods for reproducibly generating anticonvulsant GRbE, which is enriched in five panaxadiol glycosides of G-Rb1, ginsenoside Rb2 (G-Rb2), G-Rb3, ginsenoside Rc (G-Rc), and G-Rd with total ginsenosides over 90%, and for purifying G-Rb1, G-Gb3 and G-Rd with purity of 97.9%, 96.6% and 98.6%, respectively

An algorithm for solving the obstacle problems

AbstractIn this paper, we propose an algorithm for solving the obstacle problem. We try tofind the approximated region of the contact in the obstacle problem by iteration. Numerical examples are given for the obstacle problem for a membrane and the elastic-plastic torsion problem

Shape Memory Effect of Keratin Fibers

In the past thousands of years, keratin fibers were only considered as textile fibers for excellent fiber performances, such as high strength, acceptable elasticity, good thermal insulation, etc. Only recently, some indications have been obtained that keratin fiber may be a smart natural material that may subvert people’s perception of this matter. The smart attribute displays shape memory effects (SMEs) responsive to many types of stimuli including water, heat, coupled water-heat, redox agents, UV light, etc. These smart functions of keratin fibers are found to be the result of three structural components: crystals, hydrogen bonds (HBs), and disulfide bonds (DBs) among intra- and inter-keratin macromolecules. In this chapter, keratin fibers (such as camel hair) were employed for investigating their SMEs under five types of stimuli, in which the HBs, DBs, and crystals were characterized separately, as well as the fiber shape fixation and recovery ratios, respectively. The whole test results indicated that keratin hair fiber is a type of shape memory polymer and the related SME depends on the contents of the HBs, DBs, and crystalline phase inside the hair