Top quark mass measurement using the template method at CDF
Physical Review D - Particles, Fields, Gravitation and Cosmology 83:11 (2011)
Abstract:
We present a measurement of the top quark mass in the lepton+jets and dilepton channels of tt̄ decays using the data sample corresponding to an integrated luminosity of 5.6fb-1 of pp̄ collisions at Tevatron with √s=1.96TeV, collected with the CDF II detector. We construct templates of two reconstructed top quark masses from different jets-to-quarks combinations and the invariant mass of two jets from the W decays in the lepton+jets channel, and a reconstructed top quark mass and mT2, a variable related to the transverse mass in events with two missing particles, in the dilepton channel. The simultaneous fit of the templates from signal and background events in the lepton+jets and dilepton channels to the data yields a measured top quark mass of Mtop=172.1±1.1(stat)±0. 9(syst)GeV/c2. © 2011 American Physical Society.Boosted objects: A probe of beyond the standard model physics
European Physical Journal C Springer-Verlag 71:1661 (2011)
Abstract:
We present the report of the hadronic working group of the BOOST2010 workshop held at the University of Oxford in June 2010. The first part contains a review of the potential of hadronic decays of highly boosted particles as an aid for discovery at the LHC and a discussion of the status of tools developed to meet the challenge of reconstructing and isolating these topologies. In the second part, we present new results comparing the performance of jet grooming techniques and top tagging algorithms on a common set of benchmark channels. We also study the sensitivity of jet substructure observables to the uncertainties in Monte Carlo predictions.Search for production of heavy particles decaying to top quarks and invisible particles in pp collisions at √s = 1.96 TeV.
Phys Rev Lett 106:19 (2011) 191801
Abstract:
We present a search for a new particle T' decaying to top quark via T' → t + X, where X is an invisible particle. In a data sample with 4.8 fb(-1) of integrated luminosity collected by the CDF II detector at Fermilab in pp collisions with √s = 1.96 TeV, we search for pair production of T' in the lepton + jets channel, pp → tt + X + X → ℓνbqq'b + X + X. We interpret our results primarily in terms of a model where T' are exotic fourth generation quarks and X are dark matter particles. Current direct and indirect bounds on such exotic quarks restrict their masses to be between 300 and 600 GeV/c2, the dark matter particle mass being anywhere below m(T'). The data are consistent with standard model expectations, and we set 95% confidence level limits on the generic production of T'T' → tt + X + X. For the dark matter model we exclude T' at 95% confidence level up to m(T') = 360 GeV/c2 for m(X) ≤ 100 GeV/c2.Measurements of direct CP violating asymmetries in charmless decays of strange bottom mesons and bottom baryons.
Phys Rev Lett 106:18 (2011) 181802
Abstract:
We report measurements of direct CP-violating asymmetries in charmless decays of neutral bottom hadrons to pairs of charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using a data sample corresponding to 1 fb(-1) of integrated luminosity, we obtain the first measurements of direct CP violation in bottom strange mesons, A(CP)(B(s)(0)→K(-)π(+))=+0.39±0.15(stat)±0.08(syst), and bottom baryons, A(CP)(Λ(b)(0)→pπ(-))=+0.03±0.17(stat)±0.05(syst) and A(CP)(Λ(b)(0)→pK(-))=+0.37±0.17(stat)±0.03(syst). In addition, we measure CP violation in B(0)→K(+)π(-) decays with 3.5σ significance, A(CP)(B(0)→K(+)π(-))=-0.086±0.023(stat)±0.009(syst), in agreement with the current world average. Measurements of branching fractions of B(s)(0)→K(+)K(-) and B(0)→π(+)π(-) decays are also updated.Invariant mass distribution of jet pairs produced in association with a W boson in pp collisions at sqrt[s]=1.96 TeV.
Phys Rev Lett 106:17 (2011) 171801