K meson

Princeton) discovery of violations of fundamental symmetry principles in the decay of neutral K-mesons. 

Experimental Clarification in the Neutral K Meson and B Meson Systems By K. Kleinknecht 2003. 67 figs., XII, 144 pages... 

Almost at the same time Rochester and Butler61 at Manchester observed in a cloud chamber triggered by counters two V events identified later as decays of a 0° (=K°)-meson and a A°-hyperon. 

The mechanism of Aab creation is the Coulomb interaction in the final state (between a+ and b ), formatting from two virtual particles a+ and b, the bound state Aab (Fig. 1). This mechanism, in principle, allows for creation of all types of bound states and if a+ and b are relativistic particles, then Aab will also be relativistic. For ultra-relativistic atoms, there are effects caused by final time of atom formation and new phenomena during atom interaction with matter. High value of the Lorentz factors of atoms also allows for the detection new short lived bound states An, Ao and A k, consisting accordingly from (7r+p ), (7r+7r ) and (tt+ K ) mesons and to measure their parameters. 

Figures 4 and 5 show typical plots of I2p(E) and I2p( ), where l is the flight distance. Both curves reveal a distinct interference pattern which is the optical analogue of the effect predicted by Pais and Piccioni for the system of K° and K° mesons.

J. W. Cronin (Chicago) and V. L. Fitch (Princeton) discovery of violations of fundamental symmetry principles in the decay of neutral K-mesons. 

Most decay modes (other than the semileptonic modes) that involve a neutral K meson are now given as modes, not as modes. Nearly always it is A that is measured, and interference between Cabibbo-allowed and doubly Cabibbo-suppressedmodes can invalidate the assumption that 2 r K ) = r K ). 

Cosmic radiation contains a large number of the kind of particles which used to be called elementary particles. We have so far mentioned protons, electrons, neutrons, positrons, pions, muons, photons, and neutrinos. These particles can be sorted into differrat classes according to their quantum properties. Table 10.1. We have here added one more particle, the K-meson (or kaon), because of its similarity to the r-meson (pion). Kaons and pions appear in cosmic rays and high-energy nuclear reactions, cf. Fig. 10.4. As we shall see later, the baryons and mesons of Table 10.1 are not elementary in a strict sense. However, to avoid confusion we will refer to the particles in Table 10.1 as elem taiy in the appropriate nuclear reactions (cf. later Table 10.2). 

This formulation is not limited to the scattering of X-rays, but it should apply to any weak interactions in which plane waves constitute a reasonable approximation and the initial and final states of the nucleus are the same. Gp[d) is then changed to the cross-section appropriate for the process. Processes where it is convenient to think in terms of form factors include the elastic scattering of electrons (from low Z nuclei), elastic photon scattering, fji meson scattering, IJL meson pair production, and the scattering of those K mesons which have a weak nuclear interaction. The nuclear form factor is also a convenient first... 

At the Berkeley Bevatron and the Brookhaven Cosmotron beams of charged K mesons are obtained (by K mesons we mean particles with a mass about 966 electron masses and a lifetime of about 10 sec). Unfortunately in the so-called meson beam there are actually about 20 times as many n mesons present as mesons. At Berkeley in the arrangement of Birge for every... 

Hyperfragments referred to in Sect. 5 are produced when K mesons are absorbed in nuclei. 

The mesons originally proposed by Yukawa were intimately related to nuclear forces with the consequence that such particles should have strong interactions with nucleons and with nuclei, and one should find cross-sections commensurate with the size of the nucleus. Also negative mesons brought to rest in matter should disappear by nuclear capture rather than undergo free decay. 71 mesons and K mesons have been found to behave in the anticipated fashion indicating that they interact strongly with nuclei. 

Meson production, / -mesons in general are produced as the decay products of 7c and K mesons (see Table 11). However when high energy photons pass through a Coulomb field / -meson pairs should be produced by a process... 

K-mesons and hyperfragments. At the time this, article is being written there are available only early semiquantitative results on the interaction of iiC-mesons and hyperons with nuclei. Most of the experiments with such particles have been reported at the Pisa conference or at the recent Rochester conferences. ... 

The combination of two quarks (one quark and one antiquark) qq generates the bounded states of mesons (i.e., fr,k mesons or charmonium particle J /y/ = cc)... 

Matter distribution can be determined from elastic p, n, a scattering, it" ", K meson scattering, and cross sections of reactions induced by p, n, antiproton, it, and K beams. 

CPT invariance is so far fiilly supported by the available experimental evidence and it is absolutely fundamental in field theory. Nevertheless, there are many experiments trying to test it. The simplest way to do that is to compare the mass or charge of particles and antiparticles. The most precise measurement of this type is that of the relative mass difference between the neutral K meson and its antiparticle that has so far been found to be less than 10 (Amsler et al. 2008). In 1999, an Antiproton Decelerator facility (CERN 2009) was constructed at the European Particle Physics Laboratory, CERN, in order to test the CPT invariance by comparing the spectra of hydrogen and antihydrogen, the latter being the bound state of an antiproton and a positron (see Chap. 28 in Vol. 3). 

Polish physicists Marian Danysz and Jerzy Pniewski discover the K meson (or kaon) and lambda particle. American physicists Albert Ghiorso, Stanley Thompson, Gregory Ghoppin, and Glenn Seaborg discover the element einsteinium. They also discover the element fermium in the remains of the first thermonuclear explosion. 

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