On the Flavor Problem in Strongly Coupled Theories - THEP Mainz

126 Chapter 3. Solving the Flavor Problem in Strongly Coupled Theories
� � Q Q � ²
5.5
5.0
4.5
4.0
3.5
3.0
2.5
� � Q Q � ² � 2 � Q Q
2.0
1.0 1.2 1.4 1.6 1.8
� Q Q
Figure 3.8: Region in the ∆H − ∆ H † H plane which is excluded using numerical methods,
shown in blue. These bounds depend on the global symmetry of the technicolor
condensate (and become weaker for a larger symmetry group), which is assumed to
be SU(2) in this plot. The red region in the upper left corner is the preferred region
by flavor bounds on the ETC scale and a natural top mass. The green region shows
the improvement assuming a global SU(3)D × SU(3)S symmetry. The dashed cross
indicates the lowest possible value of ∆H ≡ ∆ ¯ QQ , while ∆ H † H ≡ ∆ ( ¯ QQ) 2 = 4, and the
orange line depicts the large N limit ∆ H † H = 2∆H.
then it appears, because the scalar sector needs to respect the enlarged global symmetry
as well and this will lead to a weaker bound from the numerical analysis, which
means the thick blue line in Figure 3.8 shifts up. This has not been implemented in
the plot, because the fit function has not been given in the original paper, however
compare [30, Fig. 4].
We can resume that the dual interpretation of the extended gauge sector proposed
for RS models suggests that the associated suppression of the coefficients of mixed
chirality operators can be achieved in a wider class of strongly coupled models. Experimentally,
such a global symmetry would reveal itself either by the additional
mesonic resonances or by the variety of scalars in the extended Higgs sector, which
will be the subject of Section 3.6.