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

Volatile degassing, petrology, and magma dynamics of the Villarrica Lava Lake, Southern Chile

Villarrica is a 2847-m-high, subduction zone stratovolcano located in the southern Chilean Andes (39.5°S). This volcano has been characterized by continuous, open-vent, passive degassing from a summit lava lake, with negligible eruption of magmatic material, from the end of the last eruption in 1985 to the time of writing. The major- and trace-element bulk composition of Villarrica magma (basaltic andesite) has been identical from 1984 to the present. Samples of Villarrica magma from the lava lake contain 33 wt.% plagioclase (An58-74), 7 wt.% olivine (Fo75-78), and trace amounts of chromian spinel. Glass inclusions in olivine and plagioclase are basaltic andesite in composition, are mostly degassed, and contain 30-440 ppm S, 170-360 ppm Cl, 340-600 ppm F, 0.1±0.6 wt.% H2O, and 20-70 ppm CO2. One gas-rich glass inclusion contains 920 ppm S, 530 ppm Cl, and 1.4 wt.% H2O. Matrix glasses are basaltic andesite and contain 80-150 ppm S, 190-250 ppm Cl, 440-630 ppm F, and 0.0±0.7 wt.% H2O. MELTS modeling suggests that all crystallization occurred at P 50 m of vertical deformation, but there is no visible bulging of the edifice or mass wasting of the cone caused by deformation-induced gravitational instability. Instead, convection of magma in a volcanic conduit with ∼5 m diameter is the most likely mechanism for transporting both the volatiles and heat to produce the observed gas emissions and prevent the lava lake from solidifying. © 2004 Elsevier B.V. All rights reserved.SCOPUS: ar.jinfo:eu-repo/semantics/publishe