Search for doubly charged Higgs bosons decaying to dileptons in pp collisions at square root of s=1.96 TeV

We present the results of a search for doubly charged Higgs bosons (H+/-+/-) decaying to dileptons (ll(')) using approximately 240 pb(-1) of pp collision data collected by the CDF II experiment at the Fermilab Tevatron. In our search region, given by same-sign ll(') mass m(ll('))>80 GeV/c(2) (100 GeV/c(2) for ee channel), we observe no evidence for H+/-+/- production. We set limits on sigma(pp -->H++H---->l(+)l('+)l(-)l('-)) as a function of the mass of the H+/-+/- and the chirality of its couplings. Assuming exclusive same-sign dilepton decays, we derive lower mass limits on H(+/-+/-)(L) of 133, 136, and 115 GeV/c(2) in the ee, mumu, and emu channels, respectively, and a lower mass limit of 113 GeV/c(2) on H(+/-+/-)(R) in the mumu channel, all at the 95% confidence level.     

A determination of the Cabibbo-Kobayashi-Maskawa parameter |V us| using KL decays

We present a determination of the Cabibbo-Kobayashi-Maskawa parameter |V(us)| based on new measurements of the six largest K(L) branching fractions and semileptonic form factors by the KTeV (E832) experiment at Fermilab. We find |V(us)|=0.2252+/-0.0008(KTeV)+/-0.0021(ext), where the errors are from KTeV measurements and from external sources. We also use the measured branching fractions to determine the CP violation parameter |eta(+-)|=(2.228+/-0.005(KTeV)+/-0.009(ext))x10(-3).     

Measurements of the Decay KL-->e+ e- mu+ mu-

The KTeV experiment at Fermilab has isolated a total of 132 events from the rare decay K(L)-->e+ e- mu+ mu-, with an estimated background of 0.8 events. The branching ratio of this mode is determined to be [2.69+/-0.24(stat)+/-0.12(syst)]x10(-9), with a radiative cutoff of M(2)(ee mu mu)/M(2)(K)>0.95. The first measurement using this mode of the parameter alpha from the D'Ambrosio-Isidori-Portolès (DIP) model of the K(L)gamma*gamma* vertex yields a result of -1.59+/-0.37, consistent with values obtained from other decay modes. Because of the limited statistics, no sensitivity is found to the DIP parameter beta. We use this decay mode to set limits on CP and lepton violation.     

Measurement of prompt charm meson production cross sections in pp collisions at square root s = 1.96 TeV

We report on measurements of differential cross sections dsigma/dp(T) for prompt charm meson production in ppmacr; collisions at sqrt[s]=1.96 TeV using 5.8+/-0.3 pb(-1) of data from the CDF II detector at the Fermilab Tevatron. The data are collected with a new trigger that is sensitive to the long lifetime of hadrons containing heavy flavor. The charm meson cross sections are measured in the central rapidity region |y|K-pi(+), D(*+)-->D0pi(+), D+-->K-pi(+)pi(+), D(+)(s)-->phipi(+), and their charge conjugates. The measured cross sections are compared to theoretical calculations.     

Cold acclimation improves recovery of cryopreserved grass (Zoysia and Lolium sp.)

Cold acclimation of Lolium L. and Zoysia Willd. Grass cultivars significantly increased regrowth of cryopreserved meristems. One wk of cold acclimation improved recovery following cryopreservation but extended acclimation (4-8 wk) resulted in the best regrowth. Cold acclimation also significantly increased the dehydration tolerance of both Zoysia and Lolium meristems. Lolium apices cold acclimated for 4 wk produced 60-100% regrowth following cryopreservation by slow freezing or encapsulation-dehydration. Cold-acclimated Zoysia had greater than 60% regrowth following encapsulation-dehydration when beads were dehydrated to less than 22% water content. Non-acclimated meristems of both genera had little or no regrowth. Thawed meristems grew quickly without callus formation and the plantlets produced were transplanted to pots in the greenhouse after 4 to 6 wk. Samples of each cultivar were stored in liquid nitrogen as part of the U.S. National Plant Germplasm System.     

A (1)H magnetic resonance spectroscopy study of aging in parietal white matter: implications for trials in multiple sclerosis

1H magnetic resonance spectroscopy (MRS) provides a unique tool to detect and quantify brain metabolites. In multiple sclerosis it can be used to investigate axonal loss or dysfunction through measurement of N-acetyl aspartate (NAA), a neuronal marker. Previous studies in adults have reported variable effects of aging on metabolite concentrations but have predominantly focused on changes in the elderly. This study has examined a younger adult age group to provide a reference database more applicable to the multiple sclerosis population. Single voxel (1)H MRS was carried out in 44 subjects between 22 and 62 years of age. Sixteen subjects underwent repeat examination after one year. Absolute concentrations of NA (the sum of NAA and N-acetyl aspartate glutamate), NAA, creatine/phosphocreatine (Cr), choline containing compounds (Cho) and myo-inositol (mI) were measured. NA, NAA and mI concentrations did not correlate with age but there were significant correlations between age and Cr (r = 0.43, p = 0.004) and Cho (r = 0.38, p = 0. 011) concentrations. No significant differences in metabolite concentrations were seen over one year. This study provides evidence that age-related changes of metabolite concentrations occur even in a young to middle aged adult population. This emphasizes the need to perform absolute quantification of metabolite concentrations rather than ratios and the importance of age-matching in (1)H MRS studies of multiple sclerosis.     

Advanced research in millimeter-wave vacuum electronics

Selected basic research efforts currently sponsored by the U.S. Department of Defense (DOD) and the National Science Foundation (NSF) are reviewed. Major achievements are highlighted and remaining obstacles are discussed. Future advances are suggested. Opinions expressed are solely those of the author.     

Analysis of hot-wire anemometry data in an acoustically excited turbulent flow field

This paper describes measurements undertaken on an isothermal facility to study the effects of acoustic excitation on the flow field issuing from gas turbine style fuel injectors. The highly swirling and turbulent flow field is excited with plane acoustic waves generated by loudspeakers. Emphasis is placed on the accuracy of the measured response, over the range of excitation frequencies (50–1,500 Hz), and its possible contamination by the background turbulence. Simulated data are used to assess the experimental accuracy and the established errors, using this technique, are compared with an example set of results.     

Farbstoffe

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