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Chirality (physics) A chiral phenomenon is one that is not identical to its mirror image (see the article on mathematical chirality). The spin of a particle may be used to define a handedness, or helicity, for that particle, which, in the case of a massless particle, is the same as chirality. A symmetry transformation between the two is called ...
Chirality(/kaɪˈrælɪti/) is a property of asymmetryimportant in several branches of science. The word chiralityis derived from the Greekχείρ(kheir), "hand", a familiar chiral object. An object or a system is chiralif it is distinguishable from its mirror image; that is, it cannot be superposed(not to be confused with superimposed) onto it.
t. e. In theoretical physics, quantum chromodynamics (QCD) is the study of the strong interaction between quarks mediated by gluons. Quarks are fundamental particles that make up composite hadrons such as the proton, neutron and pion. QCD is a type of quantum field theory called a non-abelian gauge theory, with symmetry group SU (3).
(Note: this explicit breaking of the chiral symmetry by non-zero masses is not to be confused with the spontaneous chiral symmetry breaking that plays a dominant role in hadronic physics.) An important consequence of such non-conservation is the neutral pion decay and the chiral anomaly, [4] which is directly related to the pion decay width. [5 ...
Therefore, the global Poincaré symmetry, consisting of translational symmetry, rotational symmetry and the inertial reference frame invariance central to the theory of special relativity must apply. The local SU(3) × SU(2) × U(1) gauge symmetry is the internal symmetry. The three factors of the gauge symmetry together give rise to the three ...
C-symmetry. In physics, charge conjugation is a transformation that switches all particles with their corresponding antiparticles, thus changing the sign of all charges: not only electric charge but also the charges relevant to other forces. The term C-symmetry is an abbreviation of the phrase "charge conjugation symmetry", and is used in ...
The SU(N f) × SU(N f) chiral flavour symmetry of the QCD Lagrangian is broken in the vacuum state of the theory. The symmetry of the vacuum state is the diagonal SU( N f ) part of the chiral group. The diagnostic for this is the formation of a non-vanishing chiral condensate ψ i ψ i , where ψ i is the quark field operator, and the flavour ...
This reduction of symmetry is a form of explicit symmetry breaking. The strength of explicit symmetry breaking is controlled by the current quark masses in QCD. Even if quarks are massless, chiral flavour symmetry can be spontaneously broken if the vacuum of the theory contains a chiral condensate (as it does in low-energy