Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set

We report a measurement of the bottom-strange meson mixing phase \beta_s using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> K+ K-) decays in which the quark-flavor content of the bottom-strange meson is identified at production. This measurement uses the full data set of proton-antiproton collisions at sqrt(s)= 1.96 TeV collected by the Collider Detector experiment at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity. We report confidence regions in the two-dimensional space of \beta_s and the B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2, -1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in agreement with the standard model expectation. Assuming the standard model value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +- 0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +- 0.009 (syst) ps, which are consistent and competitive with determinations by other experiments.Comment: 8 pages, 2 figures, Phys. Rev. Lett 109, 171802 (2012

Induction of immunotoxicity by polycyclic hydrocarbons : role of the Ah locus

We have employed the plaque forming cell (PFC) response to sheep erythrocytes as well as lymphocyte proliferation to study the induction of immunotoxicity in AHH-inducible (Ah Locus positive, C57BL/6N; B6C3F1) and AHH non-inducible (Ah Locus negative, DBA2/N) mice following administration of polycyclic aromatic hydrocarbons. When two potent carcinogenic polycyclic hydrocarbons which induce AHH activity, 3-methylcholanthrene (MCA) or 1,2,5,6-dibenzanthracene [DB(a,h)A] were administered IP, immunotoxicity was observed in both AHH-inducible and AHH non-inducible animals. However, the AHH-inducible animals appeared to be more sensitive, and substantial suppression of a PFC response toxicity could be induced with doses as low as 14 mg/kg methylcholanthrene. While suppression of a mitogen response required a dose of 43-125 mg/kg. Administration of the weak carcinogen 1,2,3,4-dibenzanthracene [DB(a,c)A], IP, which similarly induces AHH activity in inducible animals, failed to induce immunotoxicity in either C57B1/6N or DBA/2N mice. In contrast to the results obtained following IP administration, when MCA was administered repeatedly (4X) via an intragastric (IG) route we observed striking immunosuppression of a PFC response in Ah locus negative (DBA/2) animals but minimal effects in Ah locus positive animals (C57B1/6). We finally observed that a single IP dose of MCA (125 mg/kg) to Ah locus positive animals substantially inhibited Natural Killer Cell activity but had more limited effects on the ability of an animal to reject a challenge by an immunogenic syngeneic fibrosarcoma