Search for heavy resonances decaying to two Higgs bosons in final states containing four b quarks

A search is presented for narrow heavy resonances X decaying into pairs of Higgs bosons (H) in proton-proton collisions collected by the CMS experiment at the LHC at root s = 8 TeV. The data correspond to an integrated luminosity of 19.7 fb(-1). The search considers HH resonances with masses between 1 and 3 TeV, having final states of two b quark pairs. Each Higgs boson is produced with large momentum, and the hadronization products of the pair of b quarks can usually be reconstructed as single large jets. The background from multijet and t (t) over bar events is significantly reduced by applying requirements related to the flavor of the jet, its mass, and its substructure. The signal would be identified as a peak on top of the dijet invariant mass spectrum of the remaining background events. No evidence is observed for such a signal. Upper limits obtained at 95 confidence level for the product of the production cross section and branching fraction sigma(gg -> X) B(X -> HH -> b (b) over barb (b) over bar) range from 10 to 1.5 fb for the mass of X from 1.15 to 2.0 TeV, significantly extending previous searches. For a warped extra dimension theory with amass scale Lambda(R) = 1 TeV, the data exclude radion scalar masses between 1.15 and 1.55 TeV

Measurement of the top quark mass using charged particles in pp collisions at root s=8 TeV

Peer reviewe

Realizing the child\u27s perspective: An exploration of sixth-graders\u27 ideas about land use

Given the rapid rate of urbanization in the U.S., it is important to explore children\u27s conceptions of land use and to understand children\u27s relationships to the environment. In addition, the school is an important source of environmental information where curriculum and instruction play critical roles in shaping children\u27s ideas. The purpose of this study, therefore, was to investigate children\u27s conceptions of land use in the context of an environmental science class. This was a naturalistic study conducted with 13 sixth-graders and their teacher in West-central Indiana. A social constructivist framework was utilized to steer data collection and to guide interpretation. Qualitative methods such as interviews, drawings and photograph journals were used to elicit children\u27s ideas and field notes provided a rich description of the learning environment. Data were analyzed inductively and coded using case-specific criteria to organize and interpret data on an emergent basis. It was found that children in this study did not view humans as part of the environment. Land use was conceptualized as a human activity for human benefit, that is, children\u27s conceptions of land use were framed by an anthropocentric worldview. Furthermore, children\u27s conceptions of land use-related outcomes were negative and limited to large-scale, visible forms of environmental impacts. Environmental science instruction did not change these ideas; in fact, they were reinforced by the school curriculum. These findings suggest that exploring and applying the fundamental nature of children\u27s ideas in environmental education and research is essential to the development of a land ethic as well as an environmentally literate citizenry

Search for a Higgs boson decaying into γ∗γ→llγ\gamma^* \gamma \to ll \gamma with low dilepton mass in pp collisions at s=8\sqrt{s} = 8 TeV

A search is described for a Higgs boson decaying into two photons, one of which has an internal conversion to a muon or an electron pair (ll gamma). The analysis is performed using proton-proton collision data recorded with the CMS detector at the LHC at a centre-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.7 inverse femtobarns. The events selected have an opposite-sign muon or electron pair and a high transverse momentum photon. No excess above background has been found in the three-body invariant mass range 120<m[ll gamma]<150 GeV, and limits have been derived for the Higgs boson production cross section times branching fraction for the decay H to gamma* gamma to ll gamma, where the dilepton invariant mass is less than 20 GeV. For a Higgs boson with m[H]=125 GeV, a 95% confidence level (CL) exclusion observed (expected) limit is 7.7 (6.4+3.1/-2.0) times the standard model prediction. Additionally, an upper limit at 95% CL on the branching fraction of H to(JPsi) gamma for the 125 GeV Higgs boson is set at 1.5E-3

Search for third-generation scalar leptoquarks in the tτ channel in proton-proton collisions at √s =8 TeV

A search for pair production of third-generation scalar leptoquarks decaying to top quark and τ lepton pairs is presented using proton-proton collision data at a center-of-mass energy of $\sqrt{s}=8$ TeV collected with the CMS detector at the LHC and corresponding to an integrated luminosity of 19.7 fb$^{−1}$. The search is performed using events that contain an electron or a muon, a hadronically decaying τ lepton, and two or more jets. The observations are found to be consistent with the standard model predictions. Assuming that all leptoquarks decay to a top quark and a τ lepton, the existence of pair produced, charge −1/3, third-generation leptoquarks up to a mass of 685 GeV is excluded at 95% confidence level. This result constitutes the first direct limit for leptoquarks decaying into a top quark and a τ lepton, and may also be applied directly to the pair production of bottom squarks decaying predominantly via the R-parity violating coupling λ$_{333}^{′}$

Search for neutral MSSM Higgs bosons decaying into a pair of bottom quarks

A search for neutral Higgs bosons decaying into a b-bbar quark pair and produced in association with at least one additional b quark is presented. This signature is sensitive to the Higgs sector of the minimal supersymmetric standard model (MSSM) with large values of the parameter tan(beta). The analysis is based on data from proton-proton collisions at a center-of-mass energy of 8 TeV collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 19.7 inverse femtobarns. The results are combined with a previous analysis based on 7 TeV data. No signal is observed. Stringent upper limits on the cross section times branching fraction are derived for Higgs bosons with masses up to 900 GeV, and the results are interpreted within different MSSM benchmark scenarios, m[h,max], m[h,mod+], m[h,mod-], light-stau and light-stop. Observed 95% confidence level upper limits on tan(beta), ranging from 14 to 50, are obtained in the m[h,mod+] benchmark scenario