Search for jet extinction in the inclusive jet-pT spectrum from proton-proton collisions at s=8 TeV

Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published articles title, journal citation, and DOI.The first search at the LHC for the extinction of QCD jet production is presented, using data collected with the CMS detector corresponding to an integrated luminosity of 10.7  fb−1 of proton-proton collisions at a center-of-mass energy of 8 TeV. The extinction model studied in this analysis is motivated by the search for signatures of strong gravity at the TeV scale (terascale gravity) and assumes the existence of string couplings in the strong-coupling limit. In this limit, the string model predicts the suppression of all high-transverse-momentum standard model processes, including jet production, beyond a certain energy scale. To test this prediction, the measured transverse-momentum spectrum is compared to the theoretical prediction of the standard model. No significant deficit of events is found at high transverse momentum. A 95% confidence level lower limit of 3.3 TeV is set on the extinction mass scale

Searches for electroweak neutralino and chargino production in channels with Higgs, Z, and W bosons in pp collisions at 8 TeV

Searches for supersymmetry (SUSY) are presented based on the electroweak pair production of neutralinos and charginos, leading to decay channels with Higgs, Z, and W bosons and undetected lightest SUSY particles (LSPs). The data sample corresponds to an integrated luminosity of about 19.5 fb(-1) of proton-proton collisions at a center-of-mass energy of 8 TeV collected in 2012 with the CMS detector at the LHC. The main emphasis is neutralino pair production in which each neutralino decays either to a Higgs boson (h) and an LSP or to a Z boson and an LSP, leading to hh, hZ, and ZZ states with missing transverse energy (E-T(miss)). A second aspect is chargino-neutralino pair production, leading to hW states with E-T(miss). The decays of a Higgs boson to a bottom-quark pair, to a photon pair, and to final states with leptons are considered in conjunction with hadronic and leptonic decay modes of the Z and W bosons. No evidence is found for supersymmetric particles, and 95% confidence level upper limits are evaluated for the respective pair production cross sections and for neutralino and chargino mass values

Hydrogen-bonded Dimers Of Ch3och2ch2oh: Ab Initio Structures And Multivariate Analysis

Structures and vibrational frequencies of relevant hydrogen-bonded dimers of 2-methoxyethanol are obtained at the 3-21G*//AM1 level (the 3-21G* basis set included polarization functions deliberately added to second period atoms) and the results analyzed by standard multivariate methods. Dimers built from the same pair of isolated monomers belong to the same homologous series. The most stable dimer is obtained from the most stable conformations of both monomers, has a 10-membered intermolecular ring with a boat-chair-boat conformation, and presents a zero dipole moment. In addition, the most stable dimers of the three homologous series have 10-membered rings with relatively symmetric conformations and zero or very low dipole moments. The energies of the monomers in these dimers - monomers with geometries frozen in the dimer - are close to the isolated and relaxed monomers energies. Generally speaking, OH⋯O and CH⋯O hydrogen bonds are found to contribute appreciably for the stability of the dimers. In particular, for the second most stable dimer, two of the three CH⋯O hydrogen bonds are shorter than the intramolecular OH⋯O bond for the isolated monomer. Multivariate analysis of all the results shows that the O⋯H-O angle is highly correlated with the H-O bond length and that the COC and OCC angles are also highly correlated for both monomers, hence confirming that each monomer in a dimer keeps essentially the same conformation it has in the isolated monomer. The first and second principal components include all the highly correlated variables and account for 45% of the total variance. 3-D plots of the three most important principal components confirm a strong structural resemblance both for 10-membered ring dimers of homomeric series, i.e., formed by the same monomers, and for the more stable dimers in each homologous series. In addition, among the heteromeric dimers with seven membered rings, the ones whose first conformation is G or G′ are less stable and located in a separate group. © 1995 American Chemical Society.99263463

Molecular interactions in polyacrylamide/lithium perchlorate hydrogel composites

In this study, the effects of introduction of lithium perchlorate into polyacrylamide hydrogels having constant amounts of acrylamide monomers and N,N'-methylene-bis-acrylamide crosslinker have been studied through the observed changes in the vibrational Raman spectra. The changes in the perchlorate anion's Raman modes show that in the polymeric matrix most of the lithium and perchlorate ions are separated by the polyacrylamide coils. The changes in the Raman modes of the polymeric chains show that the interactions of the two ionic species with the coils are unfavourable to the hydrogen-bond network of the hydrogel matrix. As the amount of lithium perchlorate in the hydrogel increases the role played by the intra and inter-molecular hydrogen bonds due either to the amide groups or the interstitial water decreases; the amide groups become more accessible to chemical transformations and the hydrogel flexibility increases.http://www.sciencedirect.com/science/article/B6TXW-3YWWYVS-R/1/9d19af8a927c259ac2d37b5ceca3386