Gauge-coupling unification is just as successful in the standard model with six Higgs doublets as it is in the minimal supersymmetric standard model. However, the gauge couplings unify at 1014 GeV, ...which yields rapid proton decay in the SU(5) model. I propose that the grand-unified gauge group is instead SU(3)c×SU(3)L×SU(3)R, in which baryon number is conserved by the gauge interactions.
We propose techniques to observe the correlation of the spins of top quarks and antiquarks at the Tevatron and the LHC. Observation of the spin correlation would confirm that the top quark decays ...before its spin flips, and would place a lower bound on the top-quark width and
V
tb
. The spin correlation may also be a useful tool to study the weak decay amplitude of the top quark.
The road ahead Willenbrock, S.
European physical journal. C, Particles and fields,
07/2004, Letnik:
34, Številka:
S1
Journal Article
Recenzirano
Odprti dostop
AbstractI describe the surrounding landscape on the road to the CERN Large Hadron Collider. I revisit the milestones of hadron-collider physics, and from them draw lessons for the future. I recall ...the primary motivation for the journey – understanding the mechanism of electroweak symmetry breaking – and speculate that even greater discoveries may await us. I review the physics that we know beyond the standard model – dark matter, dark energy, and neutrino masses – and discuss the status of grand-unified theories. I list the reasons why the Higgs boson is central to the standard model as well as to physics beyond the standard model.PACS: 13.85.-t
Leukocytes and their functional capacities are used extensively as biomarkers in immunological research. Commonly employed indicators concerning leukocytes are as follows: number, composition in ...blood, response to discrete stimuli, cytokine release, and morphometric characteristics. In order to employ leukocytes as biomarkers for disease and therapeutic monitoring, physiological variations and influencing factors on the parameters measured have to be considered. The aim of this report was to describe the ranges of selected leukocyte parameters in a sample of healthy horses and to analyse whether age, sex, breed, and sampling time point (time of day) influence peripheral blood leukocyte composition, cell morphology and release of cytokines ex vivo. Flow cytometric comparative characterisation of cell size and complexity in 24 healthy horses revealed significant variance. Similarly, basal release of selected cytokines by blood mononuclear cells also showed high variability TNFα (65–16,624pg/ml), IFNγ (4–80U/ml), IL-4 (0–5069pg/ml), IL-10 (49–1862pg/ml), and IL-17 (4–1244U/ml). Each animal's age influenced leukocyte composition, cell morphology and cytokine release (TNFα, IL-4, IL-10) ex vivo. Geldings showed smaller monocytes and higher spontaneous production of IL-10 when compared to the mares included. The stimulation to spontaneous release ratios of TNFα, IL-4 and IL-17 differed in Warmblood and Thoroughbred types. Sampling time influenced leukocyte composition and cell morphology. In summary, many animal factors – age being the dominant one – should be considered for studies involving the analysis of equine leukocytes. In addition, high inter-individual variances argue for individual baseline measurements.
Studying the top quark Willenbrock, S.
Reviews of modern physics,
10/2000, Letnik:
72, Številka:
4
Journal Article
Recenzirano
The top quark, discovered at the Fermilab Tevatron collider in 1995, is the heaviest known elementary particle. Its large mass suggests that it may play a special role in nature. It behaves ...differently from the other known quarks due to both its large mass and its short lifetime. Thus far we have only crude measurements of the properties of the top quark, such as its mass, weak interactions, strong interactions, and decay modes. These measurements will be made more precise when the Tevatron begins operation again in 2001. I review the present status of these measurements, and discuss their anticipated improvement.
We study meson decays mediated by the heavy gauge bosons of the Pati-Salam model of quark-lepton unification. We consider the scenarios in which the tau lepton is associated with the third, second, ...and first generation of quarks. The most sensitive probes, depending on the scenario, are rare ital K, pi, and ital B decays.
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