Lepton A lepton is an elementary, spin-1⁄2 particle that does not undergo strong interactions, but is subject to the Pauli exclusion principle.[1] The best known of all leptons is the electron, which governs nearly all of chemistry as it is found in atoms and is directly tied to all chemical properties. Two main classes of leptons exist: charged leptons (also known as the electron-like leptons), and neutral leptons (better known as neutrinos). Charged leptons can combine with other particles to form various composite particles such as atoms and positronium, while neutrinos rarely interact with anything, and are consequently rarely observed. The first charged lepton, the electron, was theorized in the mid-19th century by several scientists[3][4][5] and was discovered in 1897 by J. J. Thomson.[6] The next lepton to be observed was the muon, discovered by Carl D. Leptons are an important part of the Standard Model. Etymology[edit] Following a suggestion of Prof. History[edit] Properties[edit]
Gluon Gluons /ˈɡluːɒnz/ are elementary particles that act as the exchange particles (or gauge bosons) for the strong force between quarks, analogous to the exchange of photons in the electromagnetic force between two charged particles.[6] In technical terms, gluons are vector gauge bosons that mediate strong interactions of quarks in quantum chromodynamics (QCD). Gluons themselves carry the color charge of the strong interaction. This is unlike the photon, which mediates the electromagnetic interaction but lacks an electric charge. Gluons therefore participate in the strong interaction in addition to mediating it, making QCD significantly harder to analyze than QED (quantum electrodynamics). Properties[edit] Diagram 1: e+e− -> Y(9.46) -> 3g Numerology of gluons[edit] Unlike the single photon of QED or the three W and Z bosons of the weak interaction, there are eight independent types of gluon in QCD. This may be difficult to understand intuitively. Color charge and superposition[edit] A.
Net present value In finance, the net present value (NPV) or net present worth (NPW)[1] of a time series of cash flows, both incoming and outgoing, is defined as the sum of the present values (PVs) of the individual cash flows of the same entity. In the case when all future cash flows are incoming (such as coupons and principal of a bond) and the only outflow of cash is the purchase price, the NPV is simply the PV of future cash flows minus the purchase price (which is its own PV). NPV is a central tool in discounted cash flow (DCF) analysis and is a standard method for using the time value of money to appraise long-term projects. Used for capital budgeting and widely used throughout economics, finance, and accounting, it measures the excess or shortfall of cash flows, in present value terms, above the cost of funds. NPV can be described as the “difference amount” between the sums of discounted: cash inflows and cash outflows. Formula[edit] where – the time of the cash flow ) where is given by: Example[edit]
Steven Weinberg Steven Weinberg (born May 3, 1933) is an American theoretical physicist and Nobel laureate in Physics for his contributions with Abdus Salam and Sheldon Glashow to the unification of the weak force and electromagnetic interaction between elementary particles. Biography[edit] Steven Weinberg was born in 1933 in New York City and graduated from Bronx High School of Science in 1950.[1] He was in the same graduating class as Sheldon Glashow, whose own research, independent of Weinberg's, would result in them (and Abdus Salam) sharing the same 1979 Nobel in Physics (see below). Weinberg received his bachelor's degree from Cornell University in 1954, living at the Cornell branch of the Telluride Association. He left Cornell and went to the Niels Bohr Institute in Copenhagen where he started his graduate studies and research. Academic career[edit] In 1966, Weinberg left Berkeley and accepted a lecturer position at Harvard. Other intellectual contributions[edit] Political ideas[edit] Personal[edit]
Technicolor (physics) Technicolor theories are models of physics beyond the standard model that address electroweak gauge symmetry breaking, the mechanism through which W and Z bosons acquire masses. Early technicolor theories were modelled on quantum chromodynamics (QCD), the "color" theory of the strong nuclear force, which inspired their name. In order to produce quark and lepton masses, technicolor has to be "extended" by additional gauge interactions. Particularly when modelled on QCD, extended technicolor is challenged by experimental constraints on flavor-changing neutral current and precision electroweak measurements. It is not known what is the extended technicolor dynamics. Much technicolor research focuses on exploring strongly interacting gauge theories other than QCD, in order to evade some of these challenges. The mechanism for the breaking of electroweak gauge symmetry in the Standard Model of elementary particle interactions remains unknown. forms. . Here, at the scale μ. is small there. . and
W and Z bosons The W bosons are named after the weak force. The physicist Steven Weinberg named the additional particle the "Z particle",[3] and later gave the explanation that it was the last additional particle needed by the model. The W bosons had already been named, and the Z bosons have zero electric charge.[4] The two W bosons are verified mediators of neutrino absorption and emission. During these processes, the W boson charge induces electron or positron emission or absorption, thus causing nuclear transmutation. The Z boson mediates the transfer of momentum, spin and energy when neutrinos scatter elastically from matter (a process which conserves charge). Basic properties[edit] These bosons are among the heavyweights of the elementary particles. Weak nuclear force[edit] The W and Z bosons are carrier particles that mediate the weak nuclear force, much as the photon is the carrier particle for the electromagnetic force. W bosons[edit] The W bosons are best known for their role in nuclear decay.
What are Present Value and Future Value Finance is all about time and risk. It’s basically a study of how people make decisions regarding the allocation of resources over time and the handling of risks of them. Playing with it requires some very fundamental techniques and strategies, which are all indispensable if not enough for success in financial markets. And the idea of present value is one of the most important that will help you value financial assets over time thus making choices between current resources and future gains. First off, money today is always more valuable than the same amount of money future. This is because you can always deposit that money in bank and roll it into a bigger amount by earning interest. Therefore, the present value of $112.5 3 years from now is $100. Present value is the amount of money today that would be needed to produce, using prevailing interest rates, a given future amount of money. In the example of $100, the future value of $100 after 3 years is $112.5. MFV = (1 + r)N * MPV Example 1
Weak isospin In particle physics, weak isospin is a quantum number relating to the weak interaction, and parallels the idea of isospin under the strong interaction. Weak isospin is usually given the symbol T or I with the third component written as or The weak isospin conservation law relates the conservation of ; all weak interactions must preserve . (electric charge), is conserved. is more important than T and often the term "weak isospin" refers to the "3rd component of weak isospin". Relation with chirality[edit] and can be grouped into doublets with that behave the same way under the weak interaction. and always transform into down-type quarks (d, s, b), which have , and vice versa. . and a neutrino (νe, νμ, ντ) with . Fermions with positive chirality (“right-handed” fermions) and anti-fermions with negative chirality (“left-handed” anti-fermions) have and form singlets that do not undergo weak interactions. Electric charge, , is related to weak isospin, , and weak hypercharge, , by See also[edit]
Meson In particle physics, mesons (/ˈmiːzɒnz/ or /ˈmɛzɒnz/) are hadronic subatomic particles composed of one quark and one antiquark, bound together by the strong interaction. Because mesons are composed of sub-particles, they have a physical size, with a radius roughly one femtometre, which is about 2⁄3 the size of a proton or neutron. All mesons are unstable, with the longest-lived lasting for only a few hundredths of a microsecond. Charged mesons decay (sometimes through intermediate particles) to form electrons and neutrinos. Uncharged mesons may decay to photons. Mesons are not produced by radioactive decay, but appear in nature only as short-lived products of very high-energy interactions in matter, between particles made of quarks. In nature, the importance of lighter mesons is that they are the associated quantum-field particles that transmit the nuclear force, in the same way that photons are the particles that transmit the electromagnetic force. History[edit] Overview[edit] If
Photon Nomenclature[edit] In 1900, Max Planck was working on black-body radiation and suggested that the energy in electromagnetic waves could only be released in "packets" of energy. In his 1901 article [4] in Annalen der Physik he called these packets "energy elements". The word quanta (singular quantum) was used even before 1900 to mean particles or amounts of different quantities, including electricity. Later, in 1905, Albert Einstein went further by suggesting that electromagnetic waves could only exist in these discrete wave-packets.[5] He called such a wave-packet the light quantum (German: das Lichtquant). The name photon derives from the Greek word for light, φῶς (transliterated phôs). Physical properties[edit] The cone shows possible values of wave 4-vector of a photon. A photon is massless,[Note 2] has no electric charge,[13] and is stable. Photons are emitted in many natural processes. Since p points in the direction of the photon's propagation, the magnitude of the momentum is
Id, ego and super-ego Although the model is structural and makes reference to an apparatus, the id, ego and super-ego are purely symbolic concepts about the mind and do not correspond to actual somatic structures of the brain (such as the kind dealt with by neuroscience). The concepts themselves arose at a late stage in the development of Freud's thought: the "structural model" (which succeeded his "economic model" and "topographical model") was first discussed in his 1920 essay Beyond the Pleasure Principle and was formalized and elaborated upon three years later in his The Ego and the Id. Freud's proposal was influenced by the ambiguity of the term "unconscious" and its many conflicting uses. Id[edit] According to Freud the id is unconscious by definition: In the id, "contrary impulses exist side by side, without cancelling each other out. ... Developmentally, the id precedes the ego; i.e., the psychic apparatus begins, at birth, as an undifferentiated id, part of which then develops into a structured ego.
Higgs mechanism In the Standard Model of particle physics, the Higgs mechanism is essential to explain the generation mechanism of the property "mass" for gauge bosons. Without the Higgs mechanism, all bosons (one of the two classes of particles, the other being fermions) would be considered massless, but measurements show that the W+, W−, and Z bosons actually have relatively large masses of around 80 GeV/c2. The Higgs field resolves this conundrum. The mechanism was proposed in 1962 by Philip Warren Anderson,[2] following work in the late 1950s on symmetry breaking in superconductivity and a 1960 paper by Yoichiro Nambu that discussed its application within particle physics. A theory able to finally explain mass generation without "breaking" gauge theory was published almost simultaneously by three independent groups in 1964: by Robert Brout and François Englert;[3] by Peter Higgs;[4] and by Gerald Guralnik, C. Standard model[edit] Structure of the Higgs field[edit] This combination of generators . and
Strong interaction In particle physics, the strong interaction (also called the strong force, strong nuclear force, nuclear strong force or color force) is one of the four fundamental interactions of nature, the others being electromagnetism, the weak interaction and gravitation. At atomic scale, it is about 100 times stronger than electromagnetism, which in turn is orders of magnitude stronger than the weak force interaction and gravitation. It ensures the stability of ordinary matter, in confining the elementary particles quarks into hadrons such as the proton and neutron, the largest components of the mass of ordinary matter. Furthermore, most of the mass-energy of a common proton or neutron is in the form of the strong force field energy; the individual quarks provide only about 1% of the mass-energy of a proton[citation needed]. In the context of binding protons and neutrons together to form atoms, the strong interaction is called the nuclear force (or residual strong force). History[edit]
Higgs boson The Higgs boson is named after Peter Higgs, one of six physicists who, in 1964, proposed the mechanism that suggested the existence of such a particle. Although Higgs's name has come to be associated with this theory, several researchers between about 1960 and 1972 each independently developed different parts of it. In mainstream media the Higgs boson has often been called the "God particle", from a 1993 book on the topic; the nickname is strongly disliked by many physicists, including Higgs, who regard it as inappropriate sensationalism.[17][18] In 2013 two of the original researchers, Peter Higgs and François Englert, were awarded the Nobel Prize in Physics for their work and prediction[19] (Englert's co-researcher Robert Brout had died in 2011). A non-technical summary[edit] "Higgs" terminology[edit] Overview[edit] If this field did exist, this would be a monumental discovery for science and human knowledge, and is expected to open doorways to new knowledge in many fields. History[edit]