Decoster, S., Cottenier, S., Wahl, U., Correia, J. G., Pereira, L. M. C., Lacasta, C., et al. (2010). Diluted manganese on the bond-centered site in germanium. Appl. Phys. Lett., 97(15), 151914–3pp.
Abstract: The functional properties of Mn-doped Ge depend to large extent on the lattice location of the Mn impurities. Here, we present a lattice location study of implanted diluted Mn by means of electron emission channeling. Surprisingly, in addition to the expected substitutional lattice position, a large fraction of the Mn impurities occupies the bond-centered site. Corroborated by ab initio calculations, the bond-centered Mn is related to Mn-vacancy complexes. These unexpected results call for a reassessment of the theoretical studies on the electrical and magnetic behavior of Mn-doped Ge, hereby including the possible role of Mn-vacancy complexes.
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CDF Collaboration(Aaltonen, T. et al), Cabrera, S., & Cuenca Almenar, C. (2010). Search for Pair Production of Supersymmetric Top Quarks in Dilepton Events from p(p)over-bar Collisions at root s=1.96 TeV. Phys. Rev. Lett., 104(25), 251801–8pp.
Abstract: We present the results of a search for pair production of the supersymmetric partner of the top quark (the top squark (t) over tilde (1)) decaying to a b quark and a chargino (chi) over tilde (+/-)(1) with a subsequent (chi) over tilde (+/-)(1) decay into a neutralino (chi) over tilde (0)(1), lepton l, and neutrino nu Using a data sample corresponding to 2.7 fb(-1) of integrated luminosity of p (p) over bar collisions at root s = 1: 96 TeV collected by the CDF II detector, we reconstruct the mass of top squark candidate events and fit the observed mass spectrum to a combination of standard model processes and (t) over tilde (1)(t) over tilde (1). We find no evidence for (t) over tilde (1)(t) over tilde (1) production and set 95% C. L. limits on the masses of the top squark and the neutralino for several values of the chargino mass and the branching ratio B((X) over tilde (+/-)(1) -> (chi) over tilde (0)(1)l(+/-)nu).
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2010). Search for WW and WZ Resonances Decaying to Electron, Missing E-T, and Two Jets in p(p)over-bar Collisions at root s=1.96 TeV. Phys. Rev. Lett., 104(24), 241801–8pp.
Abstract: Using data from 2: 9 fb(-1) of integrated luminosity collected with the CDF II detector at the Tevatron, we search for resonances decaying into a pair of on-shell gauge bosons, WW or WZ, where one W decays into an electron and a neutrino, and the other boson decays into two jets. We observed no statistically significant excess above the expected standard model background, and we set cross section limits at 95% confidence level on G* (Randall-Sundrum graviton), Z', and W' bosons. By comparing these limits to theoretical cross sections, mass exclusion regions for the three particles are derived. The mass exclusion regions for Z' and W' are further evaluated as a function of their gauge coupling strength.
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2010). Measurement of the W+W- Production Cross Section and Search for Anomalous WW gamma and WWZ Couplings in p(p)over-bar Collisions at root s 1.96 TeV. Phys. Rev. Lett., 104(20), 201801–8pp.
Abstract: This Letter describes the current most precise measurement of the W boson pair production cross section and most sensitive test of anomalous WW gamma and WWZ couplings in p (p) over bar collisions at a center-of-mass energy of 1.96 TeV. The WW candidates are reconstructed from decays containing two charged leptons and two neutrinos. Using data collected by the CDF II detector from 3: 6 fb(-1) of integrated luminosity, a total of 654 candidate events are observed with an expected background of 320 +/- 47 events. The measured cross section is sigma(p (p) over bar -> W+W- +X) = 12.1 +/- 0.9(stat)(-1.4)(+1.6)(syst) pb, which is in good agreement with the standard model prediction. The same data sample is used to place constraints on anomalous WW gamma and WWZ couplings.
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2010). Search for the Higgs Boson Using Neural Networks in Events with Missing Energy and b-Quark Jets in p(p)over-bar Collisions at root s=1.96 TeV. Phys. Rev. Lett., 104(14), 141801–7pp.
Abstract: We report on a search for the standard model Higgs boson produced in association with a W or Z boson in p (p) over bar collisions at root s = 1.96 TeV recorded by the CDF II experiment at the Tevatron in a data sample corresponding to an integrated luminosity of 2.1 fb(-1). We consider events which have no identified charged leptons, an imbalance in transverse momentum, and two or three jets where at least one jet is consistent with originating from the decay of a b hadron. We find good agreement between data and background predictions. We place 95% confidence level upper limits on the production cross section for several Higgs boson masses ranging from 110 GeV/c(2) to 150 GeV/c(2). For a mass of 115 GeV/c(2) the observed (expected) limit is 6.9 (5.6) times the standard model prediction.
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