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Belle II Detector
The BelleII experiment is a particle physics experiment designed to study the properties of B mesons (heavy particles containing a beauty quark) and other particles. BelleII is the successor to the Belle experiment, and commissioned at the SuperKEKB accelerator complex at KEK in Tsukuba, Ibaraki prefecture, Japan. The BelleII detector was "rolled in" (moved into the collision point of SuperKEKB) in April 2017. BelleII started taking data in early 2018. Over its running period, BelleII is expected to collect around 50 times more data than its predecessor mostly due to a 40-fold increase in an instantaneous luminosity provided by SuperKEKB as compared to the previous KEKB accelerator. Physics program Many interesting analyses of the Belle and BaBar experiments were limited by statistical uncertainties, which was the main motivation to build a new generation of B-factory - Belle II. The target dataset is 50 ab−1 at BelleII compared to 988 fb−1 (with 711fb−1 at the Π... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
KEK Belle II Detector (1)
, known as KEK, is a Japanese organization whose purpose is to operate the largest particle physics laboratory in Japan, situated in Tsukuba, Ibaraki Prefecture, Ibaraki prefecture. It was established in 1997. The term "KEK" is also used to refer to the laboratory itself, which employs approximately 695 employees. KEK's main function is to provide the particle accelerators and other infrastructure needed for high-energy physics, material science, structural biology, radiation science, computing science, nuclear transmutation and so on. Numerous experiments have been constructed at KEK by the internal and international collaborations that have made use of them. Makoto Kobayashi (physicist), Makoto Kobayashi, emeritus professor at KEK, is known globally for his work on CP-violation, and was awarded the 2008 Nobel Prize in Physics. History KEK was established in 1997 in a reorganization of the Institute of Nuclear Study, University of Tokyo, the University of Tokyo (established in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charmonium
In particle physics, quarkonium (from quark and -onium, pl. quarkonia) is a flavorless meson whose constituents are a heavy quark and its own antiquark, making it both a neutral particle and its own antiparticle. Light quarks Light quarks ( up, down, and strange) are much less massive than the heavier quarks, and so the physical states actually seen in experiments ( η, η′, and Ï€0 mesons) are quantum mechanical mixtures of the light quark states. The much larger mass differences between the charm and bottom quarks and the lighter quarks results in states that are well defined in terms of a quark–antiquark pair of a given flavor. Heavy quarks Examples of quarkonia are the J/ψ meson (the ground state of charmonium, ) and the meson (bottomonium, ). Because of the high mass of the top quark, toponium ( θ meson) does not exist, since the top quark decays through the electroweak interaction before a bound state can form (a rare example of a weak process proceeding ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Total Internal Reflection
Total internal reflection (TIR) is the optical phenomenon in which waves arriving at the interface (boundary) from one medium to another (e.g., from water to air) are not refracted into the second ("external") medium, but completely reflected back into the first ("internal") medium. It occurs when the second medium has a higher wave speed (i.e., lower refractive index) than the first, and the waves are incident at a sufficiently oblique angle on the interface. For example, the water-to-air surface in a typical fish tank, when viewed obliquely from below, reflects the underwater scene like a mirror with no loss of brightness (Fig.1). TIR occurs not only with electromagnetic waves such as light and microwaves, but also with other types of waves, including sound and water waves. If the waves are capable of forming a narrow beam (Fig.2), the reflection tends to be described in terms of "rays" rather than waves; in a medium whose properties are independent of direction, such as air, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Instruments And Methods In Physics Research Section A
''Nuclear Instruments and Methods in Physics Research'' (Nucl. Instrum. Methods Phys. Res.) is a peer-reviewed scientific journal published by Elsevier Elsevier () is a Dutch academic publishing company specializing in scientific, technical, and medical content. Its products include journals such as '' The Lancet'', ''Cell'', the ScienceDirect collection of electronic journals, '' Trends'', .... It was established in 1957 as ''Nuclear Instruments''. It focuses on detectors descriptions and data analysis methods. History *''Nuclear Instruments'' (1957–1958) *''Nuclear Instruments and Methods'' (1959–1981) *''Nuclear Instruments and Methods in Physics Research'' (1981–present) :*''Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment'' (1984–present) :*''Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms'' (1984–present) External links ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ring-imaging Cherenkov Detector
The ring-imaging Cherenkov, or RICH, detector is a device for identifying the type of an electrically charged subatomic particle of known momentum, that traverses a transparent refractive medium, by measurement of the presence and characteristics of the Cherenkov radiation emitted during that traversal. RICH detectors were first developed in the 1980s and are used in high energy elementary particle- , nuclear- and astro-physics experiments. This article outlines the origins and principles of the RICH detector, with brief examples of its different forms in modern physics experiments. Ring-imaging Cherenkov (RICH) detector Origins The ring-imaging detection technique was first proposed by Jacques Séguinot and Tom Ypsilantis, working at CERN in 1977. Their research and development, of high precision single-photon detectors and related optics, lay the foundations for the design development and construction of the first large-scale Particle Physics RICH detectors, at CERN ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aerogel
Aerogels are a class of synthetic porous ultralight material derived from a gel, in which the liquid component for the gel has been replaced with a gas, without significant collapse of the gel structure. The result is a solid with extremely low density and extremely low thermal conductivity. Aerogels can be made from a variety of chemical compounds. Silica aerogels feel like fragile expanded polystyrene to the touch, while some polymer-based aerogels feel like rigid foams. The first documented example of an aerogel was created by Samuel Stephens Kistler in 1931, as a result of a bet with Charles Learned over who could replace the liquid in "jellies" with gas without causing shrinkage. Aerogels are produced by extracting the liquid component of a gel through supercritical drying or freeze-drying. This allows the liquid to be slowly dried off without causing the solid matrix in the gel to collapse from capillary action, as would happen with conventional evaporation. The first aer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Particle Identification
Particle identification is the process of using information left by a particle passing through a particle detector to identify the type of particle. Particle identification reduces backgrounds and improves measurement resolutions, and is essential to many analyses at particle detectors. Charged particles Charged particles have been identified using a variety of techniques. All methods rely on a measurement of the momentum in a tracking chamber combined with a measurement of the velocity to determine the charged particle mass, and therefore its identity. Specific ionization A charged particle loses energy in matter by ionization at a rate determined in part by its velocity. The energy loss per unit distance is typically called dE/dx. The energy loss is measured either in dedicated detectors, or in tracking chambers designed to also measure energy loss. The energy lost in a thin layer of material is subject to large fluctuations, and therefore accurate dE/dx determination requir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wire Chamber
A wire chamber or multi-wire proportional chamber is a type of proportional counter that detects charged particles and photons and can give positional information on their trajectory, by tracking the trails of gaseous ionization. was located via Dr. C.N. BootPHY304 Particle Physics Sheffield University/ref> Description The multi-wire chamber uses an array of wires at high voltage (anode), which run through a chamber with conductive walls held at ground potential (cathode). Alternatively, the wires may be at ground potential and the cathode held at a high negative voltage; the important thing is that a uniform electric field draws extra electrons or negative ions to the anode wires with little lateral motion. The chamber is filled with carefully chosen gas, such as an argon/methane mix, such that any ionizing particle that passes through the tube will ionize surrounding gaseous atoms. The resulting ions and electrons are accelerated by the electric field across the chamber, causi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silicon Strip Detector
A semiconductor detector in ionizing radiation detection physics is a device that uses a semiconductor (usually silicon or germanium) to measure the effect of incident charged particles or photons. Semiconductor detectors find broad application for radiation protection, gamma and X-ray spectrometry, and as particle detectors. Detection mechanism In semiconductor detectors, ionizing radiation is measured by the number of charge carriers set free in the detector material which is arranged between two electrodes, by the radiation. Ionizing radiation produces free electrons and electron holes. The number of electron-hole pairs is proportional to the energy of the radiation to the semiconductor. As a result, a number of electrons are transferred from the valence band to the conduction band, and an equal number of holes are created in the valence band. Under the influence of an electric field, electrons and holes travel to the electrodes, where they result in a pulse that can be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Field-effect Transistor
The field-effect transistor (FET) is a type of transistor that uses an electric field to control the flow of current in a semiconductor. FETs (JFETs or MOSFETs) are devices with three terminals: ''source'', ''gate'', and ''drain''. FETs control the flow of current by the application of a voltage to the gate, which in turn alters the conductivity between the drain and source. FETs are also known as unipolar transistors since they involve single-carrier-type operation. That is, FETs use either electrons (n-channel) or holes (p-channel) as charge carriers in their operation, but not both. Many different types of field effect transistors exist. Field effect transistors generally display very high input impedance at low frequencies. The most widely used field-effect transistor is the MOSFET (metal-oxide-semiconductor field-effect transistor). History The concept of a field-effect transistor (FET) was first patented by Austro-Hungarian physicist Julius Edgar Lilienfeld in 192 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beryllium
Beryllium is a chemical element with the symbol Be and atomic number 4. It is a steel-gray, strong, lightweight and brittle alkaline earth metal. It is a divalent element that occurs naturally only in combination with other elements to form minerals. Notable gemstones high in beryllium include beryl ( aquamarine, emerald) and chrysoberyl. It is a relatively rare element in the universe, usually occurring as a product of the spallation of larger atomic nuclei that have collided with cosmic rays. Within the cores of stars, beryllium is depleted as it is fused into heavier elements. Beryllium constitutes about 0.0004 percent by mass of Earth's crust. The world's annual beryllium production of 220 tons is usually manufactured by extraction from the mineral beryl, a difficult process because beryllium bonds strongly to oxygen. In structural applications, the combination of high flexural rigidity, thermal stability, thermal conductivity and low density (1.85 times that of water) ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Center Of Mass (relativistic)
In physics, relativistic center of mass refers to the mathematical and physical concepts that define the center of mass of a system of particles in relativistic mechanics and relativistic quantum mechanics. Introduction In non-relativistic physics there is a unique and well defined notion of the center of mass vector, a three-dimensional vector (abbreviated: "3-vector"), of an isolated system of massive particles inside the 3-spaces of inertial frames of Galilei spacetime. However, no such notion exists in special relativity inside the 3-spaces of the inertial frames of Minkowski spacetime. In any rigidly rotating frame (including the special case of a Galilean inertial frame) with coordinates (t, x), the Newton center of mass of ''N'' particles of mass m_i and 3-positions \vec_(t) is the 3-vector :\vec_(t) = \frac both for free and interacting particles. In a special relativistic inertial frame in Minkowski spacetime with four vector coordinates x^ = \left(x^0, x\right ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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