Charm (redirected from charmless)

charm, magical formula or incantation, spoken or sung, for the purpose of securing blessing, good fortune, or immunity from evil. It presupposes a belief in demons or malignant spirits. The formula was frequently inscribed upon an amulet, talisman, or trinket to be worn for protection.

---

charm

In particle physics, the property or internal quantum number that is conserved in strong and electromagnetic interactions, but not in weak interactions (see strong force, electromagnetic force, weak force). Charmed particles contain at least one charmed quark; the charm number of these quarks is +1. Charmed antiquarks (see antimatter) have a charm number of −1. The first charmed particle was discovered in 1974.

---

Charm

A term used to describe a class of elementary particles. Ordinary atoms of matter consist of a nucleus composed of neutrons and protons and surrounded by electrons. Over the years, however, a host of other particles with unexpected properties have been found, associated with both electrons (leptons) and protons (hadrons). The hadrons number in the hundreds, and can be explained as composites of more fundamental constituents, called quarks. The originally simple situation of having an up quark (u) and a down quark (d) has evolved as several more varieties or flavors have had to be added. These are the strange quark (s) with the additional property or quantum number of strangeness to account for the unexpected characteristics of a family of strange particles; the charm quark (c) possessing charm and no strangeness, to explain the discovery of the J/ψ particles, massive states three times heavier than the proton; and a fifth quark (b) to explain the existence of the even more massive upsilon (γ) particles. See Hadron, Quarks

The members of the family of particles associated with charm fall into two classes: those with hidden charm, where the states are a combination of charm and anticharm quarks (cc), charmonium; and those where the charm property is clearly evident, such as the D⁺ (cd) meson and &Lgr;_c⁺ (cud) baryon. Although reasonable progress has been made in the study of charmed states, much work remains to be done. See Elementary particle

---

(language)

CHARM - An explicitly parallel programming language based on C, for both shared and nonshared MIMD computers. ftp://a.cs.uiuc.edu/pub/CHARM. Mailing list: <charm@cs.uiuc.edu>. ["The CHARM(3.2) Programming Language Manual", UIUC, Dec 1992].