γ\gamma - Z interferometry at a Φ\Phi-factory

We analyze the possibilities that the proposed $\Phi$-factories offer to measure $\gamma-Z$ interference. In the unpolarized beam case, we study different signatures in the $\rho \pi$ channel, taking advantage of the presence of the near-by $a_1$ resonance. We build a C-odd forward-backward asymmetry, estimated to be around $10^{-5}$, and (P-even, T-even) and (P-odd, T-odd) alignments of the $\rho$, to be seen from the angular distribution of its $\pi \pi$ decay products. With polarized electrons a left-right asymmetry around $2\times 10^{-4}$ is present in all channels. At leading order this asymmetry is independent of hadronic matrix elements and is sensitive to the $Z^0-s\bar{s}$ vector coupling. In the $\rho \pi$ channel, a combined left-right forward-backward asymmetry is considered.Comment: 29 pages + 6 figures. Some changes concerning $a_1$ observables, especially related with possible 2 $\gamma$ contribution

Bottonium mass - evaluation using renormalon cancellation

We present a method of calculating the bottonium mass M[Upsilon(1S)] = [2 mb + E(b barb)]. The binding energy is separated into the soft and ultrasoft components E(b barb)=[E(s)+E(us)] by requiring the reproduction of the correct residue parameter value of the renormalon singularity for the renormalon cancellation in the sum [2 mb + E(s)]. The Borel resummation is then performed separately for (2 mb) and E(s), using the infrared safe MSbar mass [bar mb] as input. E(us) is estimated. Comparing the result with the measured value of M[Upsilon(1S)], the extracted value of the quark mass is [bar mb](mu=[bar mb]) = 4.241 +- 0.068 GeV (for the central value alphas(MZ)=0.1180). This value of [bar mb] is close to the earlier values obtained from the QCD spectral sum rules, but lower than from pQCD evaluations without the renormalon structure for heavy quarkonia.Comment: 4 pages, uses espcrc2.sty, presented at QCD0

Caffeine prevents exercise-induced hypoglycemia in trained runners

The objective of this study was to analyze the physiological, biochemical, and perceptive effects of caffeine intake in marathon runners after a maximal treadmill stress test. The sample comprised randomly selected 12 male athletes of long distance races (42,125 km). The participants performed the maximal stress test twice, after ingesting a placebo and caffeine (dose de 6 mg.kg-1) capsules, using double-blind methodology. Anthropometric parameters, heart rate (HR), blood pressure (BP), and subjective perception of effort (SPE) were evaluated before, during, and after the test. Blood samples for analyses of glucose, lactate (LAC), and triglyceride (TG) levels were also collected at the same time. The maximal stress test was performed on a treadmill, and parameters such as VO2 max and subjective perception of effort (SPE) were analyzed. Before the trial and caffeine/placebo ingestion, capillary blood was collected by finger puncture for subsequent analyses. Subsequently, the maximal treadmill stress test was initiated with a 3-minute low intensity warm-up phase. The trial continued with the maximal treadmill stress test protocol, followed by a cool-down period (walk) until HR normalization. The athletes remained seated for 10 minutes, and during this period, HR and BP were measured, and blood samples were collected. HR values presented no difference between groups. However, glucose, TG, and LAC levels different after caffeine intake. The results of the present study demonstrated that caffeine ingestion modifies glucose, TG, and LAC availability during exercise in trained runners