The measured abundance of helium in the universe (about 25% of all normal matter) suggests that there is about one proton for every 1010 photons. This in turn suggests that at some earlier phase of the universe an almost equal number of protons and anti-protons existed and gradually annihilated, but that because of some fundamental asymmetry (at the level of one part per ten billion) in the way that the weak nuclear force treats matter and antimatter, protons but not anti-protons survived to the present time.
The standard model of particle physics usually enshrines this asymmetry in the form of "CP violation," a mathematical convention concerning the interaction of particles in which one imagines what happens when the charge of all the particles is reversed (charge conjugation, abbreviated as C) and the coordinates of all particles is reversed (the parity operation, or P).The standard model is successful in predicting how CP violation works out in the decay of K mesons or B mesons (see Update 600) but not so good at predicting where the abundance of baryons (protons plus neutrons) comes from.
Phil Schewe | Physics news update 614
Soft, energy-efficient robotic wings
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01.04.2015 | University of Arizona
Spring is here and ectotherms, or animals dependent on external sources to raise their body temperature, are becoming more active. Recent studies have shown...
Glass-fronted office buildings are some of the biggest energy consumers, and regulating their temperature is a big job. Now a façade element developed by Fraunhofer researchers and designers for glass fronts is to reduce energy consumption by harnessing solar thermal energy. A demonstrator version will be on display at Hannover Messe.
In Germany, buildings account for almost 40 percent of all energy usage. Heating, cooling and ventilating homes, offices and public spaces is expensive – and...
Outstanding chemical, thermal and tribological properties predestine silicon carbide for the production of ceramic components of high volume. A novel method now overcomes the procedural and technical limitations of conventional design methods for the production of components with large differences in wall thickness and demanding undercuts.
Extremely hard as diamond, shrinking-free manufacturing, resistance to chemicals, wear and temperatures up to 1300 °C: Silicon carbide (SiSiC) bundles all...
In an experiment at the Department of Energy's SLAC National Accelerator Laboratory, scientists precisely measured the temperature and structure of aluminum as...
The IPH presents a solution at HANNOVER MESSE 2015 to make ship traffic more reliable while decreasing the maintenance costs at the same time. In cooperation with project partners, the research institute from Hannover, Germany, has developed a sensor system which continuously monitors the condition of the marine gearbox, thus preventing breakdowns. Special feature: the monitoring system works wirelessly and energy-autonomously. The required electrical power is generated where it is needed – directly at the sensor.
As well as cars need to be certified regularly (in Germany by the TÜV – Technical Inspection Association), ships need to be inspected – if the powertrain stops...
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