‘Berrypicking’ in the formation of ideas about problem drinking amongst users of alcohol online support groups

Beliefs held by individuals about the illnesses or problems that affect them have been shown to impact upon the health and other outcomes that they achieve. Online support groups (OSGs) are one source of information used by those with health problems which may influence or determine what they think about their particular issue and how to resolve it. Problem drinking remains a major source of significant costs to society. This article explores whether the discussion forums of alcohol OSGs that do not follow the 12-step philosophy of Alcoholics Anonymous influence the formation of these beliefs, reporting on the outcome of thematic analysis of interviews with 25 users from five groups. It argues that Bates’ ‘Berrypicking’ model of information searching is helpful in illuminating group members’ information seeking activities. It looks at the four key aspects of berrypicking identified by Bates – the nature of the search query, the information ‘domains’ drawn on, the information retrieved and the search techniques used. The study finds that users are typically berrypickers, selecting information from different sources and forming their own interpretations

A search for charged massive long-lived particles

We report on a search for charged massive long-lived particles (CMLLPs), based on 5.2 fb$^{-1}$ of integrated luminosity collected with the D0 detector at the Fermilab Tevatron $p\bar{p}$ collider. We search for events in which one or more particles are reconstructed as muons but have speed and ionization energy loss $(dE/dx)$ inconsistent with muons produced in beam collisions. CMLLPs are predicted in several theories of physics beyond the standard model. We exclude pair-produced long-lived gaugino-like charginos below 267 GeV and higgsino-like charginos below 217 GeV at 95% C.L., as well as long-lived scalar top quarks with mass below 285 GeV.Comment: submitted to Phys. Rev. Letter

Zgamma production and limits on anomalous ZZgamma and Zgammagamma couplings in ppbar collisions at sqrt(s)=1.96 TeV

We present a measurement of ppbar->Zgamma->ll+gamma (l = e, mu) production with a data sample corresponding to an integrated luminosity of 6.2 fb^{-1} collected by the D0 detector at the Fermilab Tevatron ppbar Collider. The results of the electron and muon channels are combined, and we measure the total production cross section and the differential cross section dsigma/dp_T^gamma, where p_T^gamma is the momentum of the photon in the plane transverse to the beamline. The results obtained are consistent with the standard model predictions from next-to-leading order calculations. We use the transverse momentum spectrum of the photon to place limits on anomalous ZZgamma and Zgammagamma couplings

Measurements of single top quark production cross sections and |Vtb| in ppbar collisions at sqrt{s}=1.96 TeV

We present measurements of production cross sections of single top quarks in \ppbar collisions at $\sqrt{s}=1.96\;\rm TeV$ in a data sample corresponding to an integrated luminosity of $5.4\;\rm fb^{-1}$ collected by the D0 detector at the Fermilab Tevatron Collider. We select events with an isolated electron or muon, an imbalance in transverse energy, and two, three, or four jets, with one or two of them containing a bottom hadron. We obtain an inclusive cross section of \sigma({\ppbar}{\rargap}tb+X, tqb+X) = 3.43\pm^{0.73}_{0.74}\;\rm pb and use it to extract the CKM matrix element $0.79 < |V_{tb}| \leq 1$ at the 95% C.L. We also measure \sigma({\ppbar}{\rargap}tb+X) = 0.68\pm^{0.38}_{0.35}\;\rm pb and \sigma({\ppbar}{\rargap}tqb+X) = 2.86\pm^{0.69}_{0.63}\;\rm pb when assuming, respectively, $tqb$ and $tb$ production rates as predicted by the standard model.Comment: 11 pages, 8 figures, submitted to Phys. Rev.

Search for a Narrow ttbar Resonance in ppbar Collisions at sqrt{s}=1.96 TeV

We report a search for a narrow ttbar resonance that decays into a lepton+jets final state based on an integrated luminosity of 5.3/fb of proton-antiproton collisions at sqrt{s}=1.96 TeV collected by the D0 Collaboration at the Fermilab Tevatron Collider. We set upper limits on the production cross section of such a resonance multiplied by its branching fraction to ttbar which we compare to predictions for a leptophobic topcolor Z' boson. We exclude such a resonance at the 95% confidence level for masses below 835 GeV.Comment: 7 pages, 3 figures, submitted to Physical Review Letter

Search for pair production of the scalar top quark in muon+tau final states

We present a search for the pair production of scalar top quarks ($\tilde{t}_{1}$), the lightest supersymmetric partners of the top quarks, in $p\bar{p}$ collisions at a center-of-mass energy of 1.96 TeV, using data corresponding to an integrated luminosity of {7.3 $fb^{-1}$} collected with the \dzero experiment at the Fermilab Tevatron Collider. Each scalar top quark is assumed to decay into a $b$ quark, a charged lepton, and a scalar neutrino ($\tilde{\nu}$). We investigate final states arising from $\tilde{t}_{1} \bar{\tilde{t}_{1}} \rightarrow b\bar{b}\mu\tau \tilde{\nu} \tilde{\nu}$ and $\tilde{t}_{1} \bar{\tilde{t}_{1}} \rightarrow b\bar{b}\tau\tau \tilde{\nu} \tilde{\nu}$. With no significant excess of events observed above the background expected from the standard model, we set exclusion limits on this production process in the ($m_{\tilde{t}_{1}}$,$m_{\tilde{\nu}}$) plane.Comment: Submitted to Phys. Lett.

Search for Higgs bosons of the minimal supersymmetric standard model in p-pbar collisions at sqrt(s)=1.96 TeV

We report results from searches for neutral Higgs bosons produced in p-pbar collisions recorded by the Dzero experiment at the Fermilab Tevatron Collider. We study the production of inclusive neutral Higgs boson in the tautau final state and in association with a b quark in the btautau and bbb final states. These results are combined to improve the sensitivity to the production of neutral Higgs bosons in the context of the minimal supersymmetric standard model (MSSM). The data are found to be consistent with expectation from background processes. Upper limits on MSSM Higgs boson production are set for Higgs boson masses ranging from 90 to 300 GeV. We exclude tanBeta>20-30 for Higgs boson masses below 180 GeV. These are the most stringent constraints on MSSM Higgs boson production in p-pbar collisions.Comment: Submitted to Phys. Lett.

Model independent search for new phenomena in pp(bar) collisions at sqrt(s) =1.96 TeV

We describe a model independent search for physics beyond the standard model in lepton final states. We examine 117 final states using 1.1 fb$^{-1}$ of $p \bar{p}$ collisions data at $\sqrt{s} = 1.96$ TeV collected with the D0 detector. We conclude that all observed discrepancies between data and model can be attributed to uncertainties in the standard model background modeling, and hence we do not see any evidence for physics beyond the standard model.Comment: Submitted to PRD. 20 pages, 21 figure

Measurement of the CP-violating phase ϕsJ/ψϕ\phi_s^{J/\psi \phi} using the flavor-tagged decay Bs0→J/ψϕB_s^0 \rightarrow J/\psi \phi in 8 fb−1^{-1} of p \barp collisions

We report an updated measurement of the CP-violating phase, $\phi_s^{J/\psi \phi}$, and the decay-width difference for the two mass eigenstates, $\Delta \Gamma_s$, from the flavor-tagged decay $B_s^0 \rightarrow J/\psi \phi$. The data sample corresponds to an integrated luminosity of 8.0 fb$^{-1}$ accumulated with the D0 detector using p \barp collisions at $\sqrt{s} = 1.96$ TeV produced at the Fermilab Tevatron collider. The 68% confidence level intervals, including systematic uncertainties, are $\Delta \Gamma_s = 0.163 +0.065 -0.064 ps^{-1}$ and $\phi_s^{J/\psi \phi} = -0.55 +0.38 -0.36$. The $p$-value for the Standard Model point is 29.8%.Comment: Submitted to Phys. Rev. D. 30 pages, 28 figure

A measurement of the WZ and ZZ production cross sections using leptonic final states in 8.6 fb−1^{-1} of ppˉp\bar{p} collisions

We study the processes $p\bar{p} \rightarrow WZ \rightarrow \ell\nu\ell^+\ell-$ and $p\bar{p} \rightarrow ZZ \rightarrow \ell^+\ell^-\nu\bar{\nu}, where$\ell$=$e$or${\mu}$. Using 8.6 fb$^{-1} of integrated luminosity collected by the D0 experiment at the Fermilab Tevatron collider, we measure the $WZ$ production cross section to be 4.50$^{+0.63}_{-0.66} pb which is consistent with, but slightly above a prediction of the standard model. The ZZ cross section is measured to be 1.64$\pm$0.46 pb, in agreement with a prediction of the standard model. Combination with an earlier analysis of the$ZZ \rightarrow \ell^+\ell^-\ell^+\ell^-$channel yields a$ZZ$cross section of 1.44$^{+0.35}_{-0.34}$ pb.Comment: Submitted to Phys. Rev.