نتایج جستجو برای: photons
تعداد نتایج: 47312 فیلتر نتایج به سال:
pet (positron emission tomography) is a powerful imaging technique that can provide quantitative information on the distribution of positron emitter labeled radiopharmaceuticals (pet radiopharmaceuticals) in the body. positrons (ß+) are positively charged beta particles. they are emitted when the atom is proton rich. a positron has only a transient existence. after losing all of its kinetic ene...
With the help of the Seiberg-Witten map, one can obtain an effective action of a deformed QED from a noncommutative QED. Starting from the deformed QED, we investigate the propagation of photons in the background of electromagnetic field, up to the leading order of the noncommutativity parameter. In our setting (both the electric and magnetic fields are parallel to the coordinate axis x and the...
The uncertainty relation for the photons in three dimensions that overcomes the difficulties caused by the nonexistence of the photon position operator is derived in quantum electrodynamics. The photon energy density plays the role of the probability density in configuration space. It is shown that the measure of the spatial extension based on the energy distribution in space leads to an inequa...
It is assumed that three lepton families (ν e , e), (ν µ , µ), (ν τ , τ) carry charges, which are sources of electronic, muonic and tauonic massless vector particles, respectively. Various manifestations of these hypothetical photons are discussed. We know only one photon that is coupled to the electric charge of particles. One of the most fundamental properties of the electric charge is its co...
Hai-Xiao Wang, ∗ Yige Chen, ∗ Zhi Hong Hang, Hae-Young Kee, 3, † and Jian-Hua Jiang † College of Physics, Optoelectronics and Energy, & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, 1 Shizi Street, Suzhou 215006, China Department of Physics, University of Toronto, Toronto, M5S 1A7, Canada Canadian Institute for Advanced Research, Toronto, Ontario, M5...
sNN = 200GeV with the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) is given. Direct-photon yields for pT & 4GeV/c and photon-hadron azimuthal correlations were determined with the aid of an electromagnetic calorimeter. By detecting ee pairs from the internal conversion of virtual photons direct-photon yields were measured between 1 . pT . 4GeV/c. In Au+Au collisions thermal p...
A search for ultra-high energy photons with energies above 1 EeV is performed using nine years of data collected by the Pierre Auger Observatory in hybrid operation mode. An unprecedented separation power between photon and hadron primaries is achieved by combining measurements of the longitudinal air-shower development with the particle content at ground measured by the fluorescence and surfac...
BosonSampling is an intermediate model of quantum computation where linear-optical networks are used to solve sampling problems expected to be hard for classical computers. Since these devices are not expected to be universal for quantum computation, it remains an open question of whether any error-correction techniques can be applied to them, and thus it is important to investigate how robust ...
Recent studies have elucidated how the absorption of a photon in a rod or cone cell leads to the generation of the amplified neural signal that is transmitted to higher-order visual neurons. Photoexcited visual pigment activates the GTP-binding protein transducin, which in turn stimulates cGMP phosphodiesterase. This enzyme hydrolyzes cGMP, allowing cGMP-gated cationic channels in the surface m...
The study of penetrating probes constitutes a key aspect of the relativistic heavy ion program. In the hadronic sector, jet quenching, for example, has been a striking revelation, and has contributed to expose the qualitatively different physics that appeared in the transition from the SPS to RHIC. In this context, electromagnetic radiation also defines a privileged class of observables owing m...
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