CMS pixel module qualification and Monte-Carlo study of H→ τ⁺τ⁻→ l⁺l⁻Eτ

The first part of this work reports on the development of test and calibration algorithms for the qualification of the barrel modules of the CMS pixel detector. Several algorithms to test the hardware functionality and performance have been developed and implemented into an object-oriented software framework. Examples are the pixel readout test, the bump bonding test or the noise measurement. The qualification procedure also includes calibration routines. For instance the gain of each pixel or the temperature sensors of the readout chips have to be calibrated. Furthermore, an algorithm to unify the thresholds of all pixels was developed. According to specific quality criteria, each module is graded into one of three categories. Out of 981 tested modules, 806 were qualified for the usage in the detector. The second part of this work deals with a Monte-Carlo study of the Higgs decay channel $H\to \tau^{+}\tau^{-} \to l^{+}l^{-}Et$ with a jet balancing the large transverse momentum of the Higgs boson. In contrast to many other studies, the analysis concentrates not on the vector boson fusion but on the gluon fusion production mechanism. The backgrounds are mainly suppressed by requiring a large invariant mass of the Higgs boson and the balancing jet. The discovery potential is limited by the resolution of the reconstructed missing transverse energy. To improve the resolution, a method to calibrate the missing transverse energy with the help of $Z^{0}/\gamma^{*} \to l^{+}l^{-}$ events was developed. Combining all lepton channels, a signal significance of 2.4$\sigma$ significance is expected for a Higgs boson of 120 GeV mass and an integrated luminosity of 30 $fb^{−1}$

SM and MSSM Higgs Boson Production: Spectra at large transverse Momentum

Strategies for Higgs boson searches require the knowledge of the total production cross section and the transverse momentum spectrum. The large transverse momentum spectrum of the Higgs boson produced in gluon fusion can be quite different in the Standard Model and the Minimal Supersymmetric Standard Model. In this paper we present a comparison of the Higgs transverse momentum spectrum obtained using the PYTHIA event generator and the HIGLU program as well as the program HQT, which includes NLO corrections and a soft gluon resummation for the region of small transverse momenta. While the shapes of the spectra are similar for the Standard Model, significant differences are observed in the spectra of Minimal Supersymmetric Standard Model benchmark scenarios with large tan(beta).Comment: 8 pages, 13 figure

Frequency of Adverse Events after Vaccination with Different Vaccinia Strains

BACKGROUND: Large quantities of smallpox vaccine have been stockpiled to protect entire nations against a possible reintroduction of smallpox. Planning for an appropriate use of these stockpiled vaccines in response to a smallpox outbreak requires a rational assessment of the risks of vaccination-related adverse events, compared to the risk of contracting an infection. Although considerable effort has been made to understand the dynamics of smallpox transmission in modern societies, little attention has been paid to estimating the frequency of adverse events due to smallpox vaccination. Studies exploring the consequences of smallpox vaccination strategies have commonly used a frequency of approximately one death per million vaccinations, which is based on a study of vaccination with the New York City Board of Health (NYCBH) strain of vaccinia virus. However, a multitude of historical studies of smallpox vaccination with other vaccinia strains suggest that there are strain-related differences in the frequency of adverse events after vaccination. Because many countries have stockpiled vaccine based on the Lister strain of vaccinia virus, a quantitative evaluation of the adverse effects of such vaccines is essential for emergency response planning. We conducted a systematic review and statistical analysis of historical data concerning vaccination against smallpox with different strains of vaccinia virus. METHODS AND FINDINGS: We analyzed historical vaccination data extracted from the literature. We extracted data on the frequency of postvaccinal encephalitis and death with respect to vaccinia strain and age of vaccinees. Using a hierarchical Bayesian approach for meta-analysis, we estimated the expected frequencies of postvaccinal encephalitis and death with respect to age at vaccination for smallpox vaccines based on the NYCBH and Lister vaccinia strains. We found large heterogeneity between findings from different studies and a time-period effect that showed decreasing incidences of adverse events over several decades. To estimate death rates, we then restricted our analysis to more-recent studies. We estimated that vaccination with the NYCBH strain leads to an average of 1.4 deaths per million vaccinations (95% credible interval, 0–6) and that vaccination with Lister vaccine leads to an average of 8.4 deaths per million vaccinations (95% credible interval, 0–31). We combined age-dependent estimates of the frequency of death after vaccination and revaccination with demographic data to obtain estimates of the expected number of deaths in present societies due to vaccination with the NYCBH and Lister vaccinia strains. CONCLUSIONS: Previous analyses of smallpox vaccination policies, which rely on the commonly assumed value of one death per million vaccinations, may give serious underestimates of the number of deaths resulting from vaccination. Moreover, because there are large, strain-dependent differences in the frequency of adverse events due to smallpox vaccination, it is difficult to extrapolate from predictions for the NYCBH-derived vaccines (stockpiled in countries such as the US) to predictions for the Lister-derived vaccines (stockpiled in countries such as Germany). In planning for an effective response to a possible smallpox outbreak, public-health decision makers should reconsider their strategies of when to opt for ring vaccination and when to opt for mass vaccination

A super-spreading ewe infects hundreds with Q fever at a farmers' market in Germany

BACKGROUND: In May 2003 the Soest County Health Department was informed of an unusually large number of patients hospitalized with atypical pneumonia. METHODS: In exploratory interviews patients mentioned having visited a farmers' market where a sheep had lambed. Serologic testing confirmed the diagnosis of Q fever. We asked local health departments in Germany to identiy notified Q fever patients who had visited the farmers market. To investigate risk factors for infection we conducted a case control study (cases were Q fever patients, controls were randomly selected Soest citizens) and a cohort study among vendors at the market. The sheep exhibited at the market, the herd from which it originated as well as sheep from herds held in the vicinity of Soest were tested for Coxiella burnetii (C. burnetii). RESULTS: A total of 299 reported Q fever cases was linked to this outbreak. The mean incubation period was 21 days, with an interquartile range of 16–24 days. The case control study identified close proximity to and stopping for at least a few seconds at the sheep's pen as significant risk factors. Vendors within approximately 6 meters of the sheep's pen were at increased risk for disease compared to those located farther away. Wind played no significant role. The clinical attack rate of adults and children was estimated as 20% and 3%, respectively, 25% of cases were hospitalized. The ewe that had lambed as well as 25% of its herd tested positive for C. burnetii antibodies. CONCLUSION: Due to its size and point source nature this outbreak permitted assessment of fundamental, but seldom studied epidemiological parameters. As a consequence of this outbreak, it was recommended that pregnant sheep not be displayed in public during the 3(rd )trimester and to test animals in petting zoos regularly for C. burnetii

Bunch mode specific rate corrections for PILATUS3 detectors

PILATUS X-ray detectors are in operation at many synchrotron beamlines around the world. This article reports on the characterization of the new PILATUS3 detector generation at high count rates. As for all counting detectors, the measured intensities have to be corrected for the dead-time of the counting mechanism at high photon fluxes. The large number of different bunch modes at these synchrotrons as well as the wide range of detector settings presents a challenge for providing accurate corrections. To avoid the intricate measurement of the count rate behaviour for every bunch mode, a Monte Carlo simulation of the counting mechanism has been implemented, which is able to predict the corrections for arbitrary bunch modes and a wide range of detector settings. This article compares the simulated results with experimental data acquired at different synchrotrons. It is found that the usage of bunch mode specific corrections based on this simulation improves the accuracy of the measured intensities by up to 40% for high photon rates and highly structured bunch modes. For less structured bunch modes, the instant retrigger technology of PILATUS3 detectors substantially reduces the dependency of the rate correction on the bunch mode. The acquired data also demonstrate that the instant retrigger technology allows for data acquisition up to 15 million photons per second per pixel.ISSN:0909-0495ISSN:1600-577