Measurements of B Rare Decays at the Tevatron

A summary of recent results on B rare decays from the CDF and D0 experiments operating in Run II of the Fermilab Tevatron is given; analyzed decay modes are B_{d,s}--> hh, B_{d,s}--> mu^{+}mu^{-}, and B--> mu^{+} mu^{-}h. Data samples are relative to 1 fb^{-1} or more integrated luminosity of p-pbar collisions at sqrt(s) = 1.96 TeV. All reported results are in agreement with Standard Model predictions and consistent with B-Factories analyzes.Comment: Proceedings of the Moriond QCD and Hdronic Interactions 2007 Conference, La Thuile, March 17-24, 200

Survey on food hygiene knowledge on board ships

Background and aim: The aim of the study was to evaluate the knowledge and attitudes on food hygiene in seafarers.Materials and methods: The study was conducted using an anonymous questionnaire presented to the workers of 7 tankers of an Italian shipping company (Finaval S.p.A.). As a reference, the analysis was extended to office employees of the same firm. Data were divided according to the rank of seafarers to assess possible differences in perceiving the risk.Results: Overall knowledge on food safety concept was not high among seafarers. In general, galley and catering workers group provided a lower percentage of correct answers than other crew members. Foodservices staff revealed little awareness of the risks linked with handling food and their perception of risk of disease transmission through food was low. Answers about risk related to specific food (eggs and fish) showed that knowledge about these problems was less than satisfactory. Moreover, the percentage of ‘I don’t know’ answers was high. These findings suggest that this personnel is aware of the right stepsof health protection in terms of food hygiene, but does not understand why it is necessary.Conclusions: Galley and catering group workers were not the most informed about food hygiene problems.This highlights the need to hire qualified personnel of the food industry on board ships. All those working inthe food service area should be properly trained on food hygiene. Seafarers should be the target of specificinformative campaigns about health risks linked with aliments, possible consequences of it and also oneson how to minimise the exposure to potentially dangerous agents/behaviours during travel/life at sea

Observation of Exclusive Gamma Gamma Production in p pbar Collisions at sqrt{s}=1.96 TeV

We have observed exclusive \gamma\gamma production in proton-antiproton collisions at \sqrt{s}=1.96 TeV, using data from 1.11 \pm 0.07 fb^{-1} integrated luminosity taken by the Run II Collider Detector at Fermilab. We selected events with two electromagnetic showers, each with transverse energy E_T > 2.5 GeV and pseudorapidity |\eta| < 1.0, with no other particles detected in -7.4 < \eta < +7.4. The two showers have similar E_T and azimuthal angle separation \Delta\phi \sim \pi; 34 events have two charged particle tracks, consistent with the QED process p \bar{p} to p + e^+e^- + \bar{p} by two-photon exchange, while 43 events have no charged tracks. The number of these events that are exclusive \pi^0\pi^0 is consistent with zero and is < 15 at 95% C.L. The cross section for p\bar{p} to p+\gamma\gamma+\bar{p} with |\eta(\gamma)| < 1.0 and E_T(\gamma) > 2.5$ GeV is 2.48^{+0.40}_{-0.35}(stat)^{+0.40}_{-0.51}(syst) pb.Comment: 7 pages, 4 figure

Search for composite and exotic fermions at LEP 2

A search for unstable heavy fermions with the DELPHI detector at LEP is reported. Sequential and non-canonical leptons, as well as excited leptons and quarks, are considered. The data analysed correspond to an integrated luminosity of about 48 pb^{-1} at an e^+e^- centre-of-mass energy of 183 GeV and about 20 pb^{-1} equally shared between the centre-of-mass energies of 172 GeV and 161 GeV. The search for pair-produced new leptons establishes 95% confidence level mass limits in the region between 70 GeV/c^2 and 90 GeV/c^2, depending on the channel. The search for singly produced excited leptons and quarks establishes upper limits on the ratio of the coupling of the excited fermio

Search for lightest neutralino and stau pair production in light gravitino scenarios with stau NLSP

Promptly decaying lightest neutralinos and long-lived staus are searched for in the context of light gravitino scenarios. It is assumed that the stau is the next to lightest supersymmetric particle (NLSP) and that the lightest neutralino is the next to NLSP (NNLSP). Data collected with the Delphi detector at centre-of-mass energies from 161 to 183 \GeV are analysed. No evidence of the production of these particles is found. Hence, lower mass limits for both kinds of particles are set at 95% C.L.. The mass of gaugino-like neutralinos is found to be greater than 71.5 GeV/c^2. In the search for long-lived stau, masses less than 70.0 to 77.5 \GeVcc are excluded for gravitino masses from 10 to 150 \eVcc . Combining this search with the searches for stable heavy leptons and Minimal Supersymmetric Standard Model staus a lower limit of 68.5 \GeVcc may be set for the stau mas

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements