|
CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2010). Search for anomalous production of events with two photons and additional energetic objects at CDF. Phys. Rev. D, 82(5), 052005–27pp.
Abstract: We present results of a search for anomalous production of two photons together with an electron, muon, tau lepton, missing transverse energy, or jets using p (p) over bar collision data from 1.1-2.0 fb(-1) of integrated luminosity collected by the Collider Detector at Fermilab (CDF). The event yields and kinematic distributions are examined for signs of new physics without favoring a specific model of new physics. The results are consistent with the standard model expectations. The search employs several new analysis
|
|
|
Constantinou, M., Dimopoulos, P., Frezzotti, R., Jansen, K., Gimenez, V., Lubicz, V., et al. (2011). B-K-parameter from N-f=2 twisted mass lattice QCD. Phys. Rev. D, 83(1), 014505–20pp.
Abstract: We present an unquenched N-f = 2 lattice computation of the B-K parameter which controls K-0 – (K) over bar (0) oscillations. A partially quenched setup is employed with two maximally twisted dynamical (sea) light Wilson quarks, and valence quarks of both the maximally twisted and the Osterwalder-Seiler variety. Suitable combinations of these two kinds of valence quarks lead to a lattice definition of the B-K parameter which is both multiplicatively renormalizable and O(a) improved. Employing the nonperturbative RI-MOM scheme, in the continuum limit and at the physical value of the pion mass we get B-K(RGI) = 0.729 +/- 0.030, a number well in line with the existing quenched and unquenched determinations.
|
|
|
BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2011). Observation of the baryonic B decay (B)over-bar(0) -> Lambda(+)(c)(Lambda)over-barK(-). Phys. Rev. D, 84(7), 071102–7pp.
Abstract: We report the observation of the baryonic B decay (B) over bar (0) -> Lambda(+)(c)Lambda K(-) with a significance larger than 7 standard deviations based on 471 x 10(6) B (B) over bar pairs collected with the BABAR detector at the PEP-II storage ring at SLAC. We measure the branching fraction for the decay (B) over bar (0) -> Lambda(+)(c)Lambda K(-) to be (3.8 +/- 0.8(stat) +/- 0.2(sys) +/- 1.0(Lambda c)(+)) x 10(-5). The uncertainties are statistical, systematic, and due to the uncertainty in the Lambda(+)(c) branching fraction. We find that the Lambda(+)(c)K(-) invariant-mass distribution shows an enhancement above 3.5 GeV/c(2).
|
|
|
CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2010). Diffractive W and Z production at the Fermilab Tevatron. Phys. Rev. D, 82(11), 112004–10pp.
Abstract: We report on a measurement of the fraction of events with a W or Z boson which are produced diffractively in (p) over barp collisions at root s = 1.96 TeV, using data from 0.6 fb-1 of integrated luminosity collected with the CDF II detector equipped with a Roman- pot spectrometer that detects the (p) over bar from (p) over bar + p -> (p) over bar + [X + W/Z]. We find that (1.00 +/- 0.11)% of Ws and (0.88 +/- 0.22)% of Zs are produced diffractively in a region of antiproton or proton fractional momentum loss xi of 0.03 < xi < 0.10 and 4-momentum transferred squared t of -1 < t < 0 (GeV/c)(2), where we account for the events in which the proton scatters diffractively while the antiproton dissociates, (p) over bar + p -> [X + W/Z] + p, by doubling the measured proton dissociation fraction. We also report on searches for W and Z production in double Pomeron exchange, (p) over bar + p -> [X + W/Z] + p, and on exclusive Z production, (p) over bar + p -> (p) over bar + Z + p. No signal is seen above background for these processes, and comparisons are made with expectations.
|
|
|
CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2010). Measurement of the top pair production cross section in the dilepton decay channel in p(p)over-bar collisions at root s = 1.96 TeV. Phys. Rev. D, 82(5), 052002–20pp.
Abstract: A measurement of the t (t) over bar production cross section in p (p) over bar collisions at root s = 1.96 TeV using events with two leptons, missing transverse energy, and jets is reported. The data were collected with the CDF II detector. The result in a data sample corresponding to an integrated luminosity 2.8 fb(-1) is sigma(t (t) over bar) = 6.27 +/- 0.73(stat) +/- 0.63(syst) +/- 0.39(lum) pb. for an assumed top mass of 175 GeV/c(2).
|
|