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R. N. Mohapatra
Fig. 10.1 Symmetry between quarks and leptons in the standard model
Fig. 10.2 Mixings between quarks in the standard model. This is a symbolic representation of the so-called Cabibbo–Kobayashi–Maskawa mixing matrix
little bit of the physical down quark mixed in it, so that part of the time, it
behaves like a down quark. A concrete manifestation of this is in the decay
like → p + π
− (see Fig. 10.3). To see this, note that the contains an s
quark which has a little bit of down quark in it. This d quark together with the
other quarks in the baryon gives a proton and pion, neither of which has
a strange quark. The is a second generation baryon, whereas the proton
and pion are the first generation particles. Thus, unless the strange quark
has the ability to change into a down quark, this process should not happen.
This is caused by the mixing between strange and down quarks. Similarly, the
bottom quark mixes with the strange quark and down quark which makes
bottom hadrons decaying to second generation or first generation hadrons.
These mixings between generations are symbolically denoted in matrix form
in Fig. 10.2. The size of the squares in the matrix is meant to show symbolically
how big the mixings are.
This mixing matrix consists of a bunch of numbers, some real and some
complex. The complex number entry signifies that there is an asymmetry
under quark and anti-quarks. This leads to all processes that distinguish
between mesons and baryons from anti-mesons and anti-baryons, containing
R. N. Mohapatra
Fig. 10.1 Symmetry between quarks and leptons in the standard model
Fig. 10.2 Mixings between quarks in the standard model. This is a symbolic representation of the so-called Cabibbo–Kobayashi–Maskawa mixing matrix
little bit of the physical down quark mixed in it, so that part of the time, it
behaves like a down quark. A concrete manifestation of this is in the decay
like → p + π
− (see Fig. 10.3). To see this, note that the contains an s
quark which has a little bit of down quark in it. This d quark together with the
other quarks in the baryon gives a proton and pion, neither of which has
a strange quark. The is a second generation baryon, whereas the proton
and pion are the first generation particles. Thus, unless the strange quark
has the ability to change into a down quark, this process should not happen.
This is caused by the mixing between strange and down quarks. Similarly, the
bottom quark mixes with the strange quark and down quark which makes
bottom hadrons decaying to second generation or first generation hadrons.
These mixings between generations are symbolically denoted in matrix form
in Fig. 10.2. The size of the squares in the matrix is meant to show symbolically
how big the mixings are.
This mixing matrix consists of a bunch of numbers, some real and some
complex. The complex number entry signifies that there is an asymmetry
under quark and anti-quarks. This leads to all processes that distinguish
between mesons and baryons from anti-mesons and anti-baryons, containing