Bounding the Z′tcZ^\prime tc coupling from D0−D0ˉD^{0}-\bar{D^{0}} mixing and single top production at the ILC

In the present work the $Z^\prime tc$ coupling is bounded by using the current experimental data on the $D^{0}-\bar{D^{0}}$ meson-mixing system. It is found that the strength associated to this coupling is less than $5.75\times 10^{-2}$. The single top production through the $e^+e^-\to Z^\prime\to tc$ process at the $Z^\prime$ boson resonance is studied and we found that around $10^7$ $tc$ events will be expected at the International Linear Collider. For the $Z^\prime\to tc$ decay, we predict a branching ratio of $10^{-2}$.Comment: Revised version. Now, 11 pages and 6 figure

Z'tc coupling from D0-D0 mixing

We bound the $Z^\prime tc$ coupling using the $D^{0}-\bar{D^{0}}$ meson mixing system. We obtained such coupling which is less than $5.75\times 10^{-2}$. We have studied the $Z^\prime$ boson resonance considering single top production in the $e^+e^-\to Z^\prime\to tc$ process. We obtained the number of events which is expected to be less than $10^7$ at the International Linear Collider scenario. We get a branching ratio of the order of $10^{-2}$ for the $Z^\prime\to tc$ decay.Comment: 4 pages, 5 figure

Study of the lepton flavor-violating Z′→τμZ'\to\tau\mu decay

The lepton flavor violating $Z^{\prime}\to\tau\mu$ decay is studied in the context of several extended models that predict the existence of the new gauge boson named $Z^\prime$. A calculation of the strength of the lepton flavor violating $Z^\prime\mu\tau$ coupling is presented by using the most general renormalizable Lagrangian that includes lepton flavor violation. We used the experimental value of the muon magnetic dipole moment to bound this coupling, from which the $\mathrm{Re}(\Omega_{L\mu\tau}\Omega^\ast_{R\mu\tau})$ parameter is constrained and it is found that $\mathrm{Re}(\Omega_{L\mu\tau}\Omega^\ast_{R\mu\tau})\sim 10^{-2}$ for a $Z^\prime$ boson mass of 2 TeV. Alongside, we employed the experimental restrictions over the $\tau\to\mu\gamma$ and $\tau\to\mu\mu^+\mu^-$ processes in the context of several models that predict the existence of the $Z^\prime$ gauge boson to bound the mentioned coupling. The most restrictive bounds come from the calculation of the three-body decay. For this case, it was found that the most restrictive result is provided by a vector-like coupling, denoted as $|\Omega_{\mu\tau}|^2$, for the $Z_\chi$ case, finding around $10^{-2}$ for a $Z^\prime$ boson mass of 2 TeV. We used this information to estimate the branching ratio for the $Z^\prime\to\tau\mu$ decay. According to the analyzed models the least optimistic result is provided by the Sequential $Z$ model, which is of the order of $10^{-2}$ for a $Z^\prime$ boson mass around 2 TeV.Comment: Revised versio

Air pollution and mortality : results from Santiago, Chile

Heavy outdoor pollution is found in developing country cities such as Jakarta, Katowice, Mexico City, and Santiago. But most epidemiological studies of dose-response relationships between particulate air pollution (PM10) and premature deaths are from Western industrial nations. This study of such relationships in developing countries by the authors fills an important gap. It is also one of the few based on monitored PM10 values, or small particles, which is likely to be a more relevant measure of exposure to air pollution than the more traditional measure of total suspended particulates. Over several years, daily measures of ambient PM10 were collected in Santiago. Data were collected for all deaths, as well as for deaths for all men, all women, and all people over 64. Deaths from respiratory and cardiovascular disease were recorded separately, and accidental deaths were excluded. Multiple regression analysis was used to explain mortality, with particular attention to the influence of season and temperature. The association persists after controlling for daily minimum temperature and binary variables indicating temperature extremes the day of the week, the month, and the year. Additional sensitivity analysis suggests robust relationships. A change equal to 10-microgram-per-cubic-meter in daily PM10 (about 9 percent) averaged over three days was associatedwith a 1.1 percent increase in mortality (95 percent confidence interval: 0.6 to 1.5 percent). Death from respiratory and cardiovascular disease was more responsive to changes in PM10 than total mortality was. The same holds for mortality among men and mortality among individuals older than 64. The results are surprising consistent with results from industrial countries.Public Health Promotion,Air Quality&Clean Air,Health Monitoring&Evaluation,Montreal Protocol,Statistical&Mathematical Sciences,Statistical&Mathematical Sciences,Montreal Protocol,Airports and Air Services,Health Economics&Finance,Health Monitoring&Evaluation

Higgs mediated lepton flavor violating tau decays τ→μγ\tau \to \mu \gamma and τ→μγγ\tau \to \mu \gamma \gamma in effective theories

The size of the branching ratios for the $\tau \to \mu \gamma$ and $\tau \to \mu \gamma \gamma$ decays induced by a lepton flavor violating Higgs interaction $H\tau \mu$ is studied in the frame of effective field theories. The best constraint on the $H\tau \mu$ vertex, derived from the know measurement on the muon anomalous magnetic moment, is used to impose the upper bounds $Br(\tau \to \mu \gamma)<2.5\times 10^{-10}$ and $Br(\tau \to \mu \gamma \gamma)<2.3\times 10^{-12}$, which are more stringent than current experimental limits on this class of transitions.Comment: 6 pages, 3 figure