Santiago Bedoya | Universidad Nacional de Colombia (National University of Colombia) (original) (raw)
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Papers by Santiago Bedoya
Results are presented from a search for a W boson using a dataset corresponding to 5.0 fb −1 of i... more Results are presented from a search for a W boson using a dataset corresponding to 5.0 fb −1 of integrated luminosity collected during 2011 by the CMS experiment at the LHC in pp collisions at √ s = 7 TeV. The W boson is modeled as a heavy W boson, but different scenarios for the couplings to fermions are considered, involving both lefthanded and right-handed chiral projections of the fermions, as well as an arbitrary mixture of the two. The search is performed in the decay channel W → tb, leading to a final state signature with a single electron or muon, missing transverse energy, and jets, at least one of which is identified as a b-jet. A W boson that couples to the right-handed (left-handed) chiral projections of the fermions with the same coupling constants as the W is excluded for masses below 1.85 (1.51) TeV at the 95% confidence level. For the first time using LHC data, constraints on the W gauge couplings for a set of left-and right-handed coupling combinations have been placed. These results represent a significant improvement over previously published limits.
Physics Letters B, 2011
A search for supersymmetry with R-parity conservation in proton-proton collisions at a centre-of-... more A search for supersymmetry with R-parity conservation in proton-proton collisions at a centre-of-mass energy of 7 TeV is presented. The data correspond to an integrated luminosity of 35 pb −1 collected by the CMS experiment at the LHC. The search is performed in events with jets and significant missing transverse energy, characteristic of the decays of heavy, pair-produced squarks and gluinos. The primary background, from standard model multijet production, is reduced by several orders of magnitude to a negligible level by the application of a set of robust kinematic requirements. With this selection, the data are consistent with the standard model backgrounds, namely tt, W + jet and Z + jet production, which are estimated from data control samples. Limits are set on the parameters of the constrained minimal supersymmetric extension of the standard model. These limits extend those set previously by experiments at the Tevatron and LEP colliders.
The Hoek-Brown failure criterion for rock masses is widely accepted and has been applied in a lar... more The Hoek-Brown failure criterion for rock masses is widely accepted and has been applied in a large number of projects around the world. While, in general, it has been found to be satisfactory, there are some uncertainties and inaccuracies that have made the criterion inconvenient to apply and to incorporate into numerical models and limit equilibrium programs. In particular, the difficulty of finding an acceptable equivalent friction angle and cohesive strength for a given rock mass has been a problem since the publication of the criterion in 1980. This paper resolves all these issues and sets out a recommended sequence of calculations for applying the criterion. An associated Windows program called "RocLab" has been developed to provide a convenient means of solving and plotting the equations presented in this paper.
Results are presented from a search for a W boson using a dataset corresponding to 5.0 fb −1 of i... more Results are presented from a search for a W boson using a dataset corresponding to 5.0 fb −1 of integrated luminosity collected during 2011 by the CMS experiment at the LHC in pp collisions at √ s = 7 TeV. The W boson is modeled as a heavy W boson, but different scenarios for the couplings to fermions are considered, involving both lefthanded and right-handed chiral projections of the fermions, as well as an arbitrary mixture of the two. The search is performed in the decay channel W → tb, leading to a final state signature with a single electron or muon, missing transverse energy, and jets, at least one of which is identified as a b-jet. A W boson that couples to the right-handed (left-handed) chiral projections of the fermions with the same coupling constants as the W is excluded for masses below 1.85 (1.51) TeV at the 95% confidence level. For the first time using LHC data, constraints on the W gauge couplings for a set of left-and right-handed coupling combinations have been placed. These results represent a significant improvement over previously published limits.
Physics Letters B, 2011
A search for supersymmetry with R-parity conservation in proton-proton collisions at a centre-of-... more A search for supersymmetry with R-parity conservation in proton-proton collisions at a centre-of-mass energy of 7 TeV is presented. The data correspond to an integrated luminosity of 35 pb −1 collected by the CMS experiment at the LHC. The search is performed in events with jets and significant missing transverse energy, characteristic of the decays of heavy, pair-produced squarks and gluinos. The primary background, from standard model multijet production, is reduced by several orders of magnitude to a negligible level by the application of a set of robust kinematic requirements. With this selection, the data are consistent with the standard model backgrounds, namely tt, W + jet and Z + jet production, which are estimated from data control samples. Limits are set on the parameters of the constrained minimal supersymmetric extension of the standard model. These limits extend those set previously by experiments at the Tevatron and LEP colliders.
The Hoek-Brown failure criterion for rock masses is widely accepted and has been applied in a lar... more The Hoek-Brown failure criterion for rock masses is widely accepted and has been applied in a large number of projects around the world. While, in general, it has been found to be satisfactory, there are some uncertainties and inaccuracies that have made the criterion inconvenient to apply and to incorporate into numerical models and limit equilibrium programs. In particular, the difficulty of finding an acceptable equivalent friction angle and cohesive strength for a given rock mass has been a problem since the publication of the criterion in 1980. This paper resolves all these issues and sets out a recommended sequence of calculations for applying the criterion. An associated Windows program called "RocLab" has been developed to provide a convenient means of solving and plotting the equations presented in this paper.