On the Flavor Problem in Strongly Coupled Theories - THEP Mainz

N M � �� �t�� NM �0�
N M � �� �t�� NM �0�
35
30
25
20
15
15
10
5
K � K
0 1 2 3
T
4 5 6
Bd � Bd
0
0 1 2 3
T
4 5 6
N M � �� �t�� NM �0�
N M � �� �t�� NM �0�
30
25
20
15
10
5
D � D
0
0 1 2 3
T
4 5 6
35
30
25
20
15
10
5
Bs� Bs
0
0 1 2 3
T
4 5 6
Figure B.1: The plots show the percentage of (anti-)mesons of a beam of 100% mesons
at T = 0 evolving over time T in (dashed) solid black. In the upper left(right) panel
for the K − K (D − D) system and in the lower left (right) panel for the Bd − Bd
(Bs − Bs) system.
In the SM, the contributions to the off-diagonal elements in (B.5) can only be generated
by W ± exchange in loops, because they correspond to ∆F = 2 neutral currents.
The relevant diagrams are box-diagrams as shown in Figure 1.8, which also include all
up-type (down-type) quarks in the case of external K, Bd or Bs (D) mesons. Because
of this virtual exchange, historically, meson mixing played an important role. The
carm mass was predicted from ∆mK measurements and similarly, the large Bd − Bd
oscillation rate gave a first hint on a really heavy top, for details see [242, Sec. 1.2] and
references therein.
Meson-antimeson mixing played also an important role in discovering C and CP violation
in the electroweak interactions. The latter represents the toughest test for New
Physics models, because the measurements do agree so well the small SM expectations.
One differentiates between CP violation in mixing, decay and in the interference of
mixing and decay. With the help of the weak Hamiltonian HW , one can define the
amplitudes
Af = 〈f|HW |M〉 , A ¯ f = 〈f|HW |M〉 , (B.11)
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