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A bstract The existence of Dark Matter (DM) in the form of Strongly Interacting Massive Particles (SIMPs) may be motivated by astrophysical observations that challenge the classical Cold DM scenario. Other observations greatly constrain, but do not completely exclude, the SIMP alternative. The signature of SIMPs at the LHC may consist of neutral, hadron-like, trackless jets produced in pairs. We show that the absence of charged content can provide a very efficient tool to suppress dijet backgrounds at the LHC, thus enhancing the sensitivity to a potential SIMP signal. We illustrate this using a simplified SIMP model and present a detailed feasibility study based on simulations, including a dedicated detector response parametrization. We evaluate the expected sensitivity to various signal scenarios and tentatively consider the exclusion limits on the SIMP elastic cross section with nucleons.

Stringent limits are set on the long-lived lepton-like sector of the phenomenological minimal supersymmetric standard model (pMSSM) and the anomaly-mediated supersymmetry breaking (AMSB) model. We derived the limits from the results presented in a recent search for long-lived charged particles in proton–proton collisions, based on data collected by the CMS detector at a centre-of-mass energy of 8 TeV at the Large Hadron Collider. In the pMSSM parameter sub-space considered, 95.9 % of the points predicting charginos with a lifetime of at least 10 ns are excluded. Furthermore, these constraints on the pMSSM are the first obtained at the LHC. Charginos with a lifetime greater than 100 ns and masses up to about 800 GeV in the AMSB model are also excluded. Furthermore, the method described can also be used to set constraints on other models.

An analysis of dijet events in PbPb and pp collisions is performed to explore the properties of energy loss by partons traveling in a quark-gluon plasma. Data are collected at a nucleon-nucleon center-of-mass energy of 2.76 TeV at the LHC. The distribution of transverse momentum (p sub(T)) surrounding dijet systems is measured by selecting charged particles in different ranges of p sub(T) and at different angular cones of pseudorapidity and azimuth. The measurement is performed as a function of centrality of the PbPb collisions, the p sub(T) asymmetry of the jets in the dijet pair, and the distance parameter R used in the anti-k sub(T) jet clustering algorithm. In events with unbalanced dijets, PbPb collisions show an enhanced multiplicity in the hemisphere of the subleading jet, with the p sub(T) imbalance compensated by an excess of low-p sub(T) particles at large angles from the jet axes. [Figure not available: see fulltext.]

(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).A search for a light charged Higgs boson, originating from the decay of a top quark and subsequently decaying into a charm quark and a strange antiquark, is presented. The data used in the analysis correspond to an integrated luminosity of 19.7 fb super(-1) recorded in proton-proton collisions at ... TeV by the CMS experiment at the LHC. The search is performed in the process ..., where the W boson decays to a lepton (electron or muon) and a neutrino. The decays lead to a final state comprising an isolated lepton, at least four jets and large missing transverse energy. No significant deviation is observed in the data with respect to the standard model predictions, and model-independent upper limits are set on the branching fraction ..., ranging from 1.2 to 6.5% for a charged Higgs boson with mass between 90 and 160 GeV, under the assumption that ... [Figure not available: see fulltext.]

Here, results are reported from a search for the pair production of top squarks, the supersymmetric partners of top quarks, in final states with jets and missing transverse momentum. The data sample used in this search was collected by the CMS detector and corresponds to an integrated luminosity of 18.9 fb–1 of proton-proton collisions at a centre-of-mass energy of 8 TeV produced by the LHC. The search features novel background suppression and prediction methods, including a dedicated top quark pair reconstruction algorithm. The data are found to be in agreement with the predicted backgrounds. Exclusion limits are set in simplified supersymmetry models with the top squark decaying to jets and an undetected neutralino, either via a top quark or through a bottom quark and chargino. Models with the top squark decaying via a top quark are excluded for top squark masses up to 755 GeV in the case of neutralino masses below 200 GeV. For decays via a chargino, top squark masses up to 620 GeV are excluded, depending on the masses of the chargino and neutralino.

One of the subjects of interest in the last years, is to develop new applications of fly ash, produced in growing quantities by burning coal in all coal-fired power stations. In this study, we have investigated the possible effects of Kosova lignite fly ash as adsorbent for removal of heavy metal ions in standard solutions, industrial wastewater and the natural water body (Sitnica river). Achieved results showed that 10 minutes of contact time, for standard solutions and natural water body, were appropriate for efficient adsorption of ions reaching the maximum removal to 99.89 wt% and 60 minutes of contact time for industrial wastewater, reaching the maximum removal of 98.12%.

(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).A search is presented for a singly produced excited bottom quark (b super(*)) decaying to a top quark and a W boson in the all-hadronic, lepton+jets, and dilepton final states in proton-proton collisions at ... TeV recorded by the CMS experiment at the CERN LHC. Data corresponding to an integrated luminosity of 19.7 fb super(-1) are used. No significant excess of events is observed with respect to standard model expectations. We set limits at 95% confidence on the product of the b super(*) quark production cross section and its branching fraction to tW. The cross section limits are interpreted for scenarios including left-handed, right-handed, and vector-like couplings of the b super(*) quark and are presented in the two-dimensional coupling plane based on the production and decay coupling constants. The masses of the left-handed, right-handed, and vector-like b super(*) quark states are excluded at 95% confidence below 1390, 1430, and 1530 GeV, respectively, for benchmark couplings. This analysis gives the most stringent limits on the mass of the b super() quark to date. [Figure not available: see fulltext.]

A search for new phenomena is performed in final states containing one or more jets and an imbalance in transverse momentum in pp collisions at a centre-of-mass energy of 13 $$\\,\\text {TeV}$$ TeV. The analysed data sample, recorded with the CMS detector at the CERN LHC, corresponds to an integrated luminosity of 2.3 $$\\,\\text {fb}^{-1}$$ fb-1. Several kinematic variables are employed to suppress the dominant background, multijet production, as well as to discriminate between other standard model and new physics processes. The search provides sensitivity to a broad range of new-physics models that yield a stable weakly interacting massive particle. The number of observed candidate events is found to agree with the expected contributions from standard model processes, and the result is interpreted in the mass parameter space of fourteen simplified supersymmetric models that assume the pair production of gluinos or squarks and a range of decay modes. For models that assume gluino pair production, masses up to 1575 and 975 $$\\,\\text {GeV}$$ GeV are excluded for gluinos and neutralinos, respectively. For models involving the pair production of top squarks and compressed mass spectra, top squark masses up to 400 $$\\,\\text {GeV}$$ GeV are excluded.

Searches are presented for direct production of top or bottom squark pairs in proton–proton collisions at the CERN LHC. Two searches, based on complementary techniques, are performed in all-jet final states that are characterized by a significant imbalance in transverse momentum. An additional search requires the presence of a charged lepton isolated from other activity in the event. The data were collected in 2015 at a centre-of-mass energy of 13 $$\\,\\text {TeV}$$ TeV with the CMS detector and correspond to an integrated luminosity of 2.3 $$\\,\\text {fb}^{-1}$$ fb-1. No statistically significant excess of events is found beyond the expected contribution from standard model processes. Exclusion limits are set in the context of simplified models of top or bottom squark pair production. Models with top and bottom squark masses up to 830 and 890 $$\\,\\text {GeV}$$ GeV, respectively, are probed for light neutralinos. For models with top squark masses of 675 $$\\,\\text {GeV}$$ GeV, neutralino masses up to 260 $$\\,\\text {GeV}$$ GeV are excluded at 95% confidence level.

A measurement of the top quark pair production ( $$\\mathrm{t}\\overline{\\mathrm{t}} $$ tt¯) cross section in proton–proton collisions at the centre-of-mass energy of 8 $$\\,\\text {TeV}$$ TeV is presented using data collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 19.6 $$\\,\\text {fb}^{-\\text {1}}$$ fb-1. This analysis is performed in the $$\\mathrm{t}\\overline{\\mathrm{t}} $$ tt¯ decay channels with one isolated, high transverse momentum electron or muon and at least four jets, at least one of which is required to be identified as originating from hadronization of a b quark. The calibration of the jet energy scale and the efficiency of b jet identification are determined from data. The measured $$\\mathrm{t}\\overline{\\mathrm{t}} $$ tt¯ cross section is $$228.5 \\pm 3.8\\,\\text {(stat)} \\pm 13.7\\,\\text {(syst)} \\pm 6.0\\,\\text {(lumi)} \\text { pb} $$ 228.5±3.8(stat)±13.7(syst)±6.0(lumi) pb. This measurement is compared with an analysis of 7 $$\\,\\text {TeV}$$ TeV data, corresponding to an integrated luminosity of 5.0 $$\\,\\text {fb}^{-\\text {1}}$$ fb-1, to determine the ratio of 8 $$\\,\\text {TeV}$$ TeV to 7 $$\\,\\text {TeV}$$ TeV cross sections, which is found to be $$1.43 \\pm 0.04\\,\\text {(stat)} \\pm 0.07\\,\\text {(syst)} \\pm 0.05\\,\\text {(lumi)} $$ 1.43±0.04(stat)±0.07(syst)±0.05(lumi). The measurements are in agreement with QCD predictions up to next-to-next-to-leading order.