Quark bottom

Even if allowed by the CPT theorem, the non-conservation of CP symmetry was hard to accept - not least because it was not consistent with the Standard Model. In 1972, Kobayashi and Maskawa predicted that CP violation would be consistent with the Standard Model provided that three generations of quarks exist (and only two were known at the time). The subsequent discoveries of the r lepton by Pearls (1975) and of the top and bottom quarks at the Fermilab confirmed the existence of a third family, this resulted in the incorporation of the CP violation into the Standard Model. 

The six quarks, namely the up quark (u), the down quark (d), the strange quark (s), the charm quark (c), the top quark (t), sometimes also called truth quark, and the bottom quark (b), also dubbed beauty quark, carry a colour charge. The bosons that act on colour, are called gluons, which are the carriers of the colour interaction. The residue of this interaction is the strong nuclear interaction, which is operative between the hadrons (for instance the proton and the neutron within an atomic nucleus). 

The prime for the down, the strange and the bottom quark is a tribute to the strangeness changing decays, that are observed experimentally, and... 

The bottom quark is therefore only weakly coupled to the down and the strange quark. 

B-meson Symbol B . A meson that consists of a down quark and an anti-bottom quark. 

It is electrically neutral, has spin zero, and a mass of 5279 GeV. The antiparticle consists BSl of a bottom quark and an anti-down quark. 

CDF Collaboration, Measurement of the bottom quark production cross section using semi-leptonic decay electrons in p p collisions at =1.8 TeV. Phys. Rev. Lett. 71, 500-504 (1993)... 

In Chapter 12 we will discuss the spectroscopy of hidden charm and bottom or charmonium and bottomonium in which the actual hadrons have charm and bottom quantum number equal zero. However, when one combines a charm or bottom quark with the old light u, d, s quarks, new families of charm or bottom hadrons are predicted to exist. This will be taken up in Chapter 13. 

In contrast to the charm case, the bottom quark charge assignment Qh = —1/3 comes from the moderate increase of R above the b threshold. This assignment is confirmed by the charge of the B ub). 

Figure 3. Deformed Fermi seas and the quark pair on each surface. The top figures show those in the absence of A and the middle figures diffusion of the Fermi surfaces in the presence of A . The bottom ones show the quark pairing on the Fermi surfaces.

Chemistry is the central science in the sense that it provides the tie between physics on the one hand and biology on the other. The world of physics, seen broadly, covers a wide spectrum. In general, the concerns of physics focus on entities smaller or larger than those of direct interest to chemistry. At the micro level physics unravels the mysteries of the elementary particles, known generally as fermions, which constimte all ordinary matter. Fermions include the quarks and their antiparticles, the antiquarks. There are six kinds of quarks, known as top, bottom, strange, charm,... 

Quark a fundamental particle hypothesized to form the basic building blocks of all matter there are six different quark types up, down, strange, charm, top, and bottom... 

There are six quarks and they have the whimsical names up, down, charm, strange, top, and bottom. As shown in Table 1, quarks have a fraction of a charge, either+2/3 or-1/3. 

Quarks were first identified by observing the products formed in high-energy nuclear collisions. Six types of quarks are recognized. Each quark type is known as a flavor. The six flavors are up, down, top, bottom, strange, and charm. Only two of these—the up and down quarks—compose protons and neutrons. A proton is made up of two up quarks and one down quark, while a neutron consists of one up quark and two down quarks. The other four types of quarks exist only in unstable particles that spontaneously break down during a fraction of a second. 

Protons and neutrons each contain three quarks. A neutron consists of one up quark and two down quarks. A proton consists of two up quarks and one down quark. Other quarks are named strange, charm, bottom, and top., but these four are not part of atoms. Quarks are a fundamental constituent of matter according to current standard model of particle physics, but individual quarks are not seen. Instead they are always confined within other subatomic particles. There is no need to consider quarks when describing chemical interactions. Only electrons are involved in chemical reactions. The position and sizes of these particles in a helium atom is indicated in the diagram at right. A diagram... 

Quarks come in six different types, or flavors up and down, top and bottom, and charm and strange. Protons and neutrons are made of up (u) quarks (which have a charge of + ) and down (d) quarks (which have a charge of — g). A proton is made from two u quarks (+ )(+1) and one d quark (— g), giving a total charge of +1. A neutron contains one u quark (+ ) and two d quarks (—g)(—g) for a total charge of zero. 

The well-known proton, neutron, and electron are now thought to be members of a group that includes other fundamental particles that have been discovered or hypothesized by physicists. These very elemental particles, of which all matter is made, are now thought to belong to one of two families namely, quarks or leptons. Each of these two families consists of six particles. Also, there are four different force carriers that lead to interactions between particles. The six members or flavors of the quark family are called up, charm, top, down, strange, and bottom. The force carriers for the quarks are the gluon and the photon. The six members of the lepton family are the e neutrino, the mu neutrino, the tau neutrino, the electron, the muon particle, and the tau particle. The force carriers for these are the w boson and the z boson. Furthermore, it appears that each of these particles has an anti-particle that has an opposite electrical charge from the above particles. 

The second family in Table 10.2 contains the "heavy electron", the muon and the muon neutrino, and the charm and the strange quarks. The third family contains the tau particle, the tau electron, and the two quarks referred to as top (or truth) and bottom (or beauty). These quarks can only be produced in high energy particle reactions. 

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