On the Flavor Problem in Strongly Coupled Theories - THEP Mainz
On the Flavor Problem in Strongly Coupled Theories - THEP Mainz
On the Flavor Problem in Strongly Coupled Theories - THEP Mainz
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192 Appendix D. Higgs Potential for <strong>the</strong> Extended Scalar Sector<br />
structure only appears <strong>in</strong> <strong>the</strong> terms which mix all three fields,<br />
Q ijkl<br />
ABCD (x) ≡ xiTr � � � �<br />
TATB Tr TCTD + xjTr � �<br />
TATDTCTB<br />
(D.3)<br />
+xkTr � � � �<br />
TATD Tr TBTC + xlTr � �<br />
TATBTCTD ,<br />
P ij<br />
ABCD (y) ≡ yiTr � � � �<br />
TATB Tr TCTD + yjTr � �<br />
TATDTBTC ,<br />
� �2 Nc<br />
RABC ≡ δA0δB0δC0 −<br />
2<br />
Nc � � �<br />
Tr TATB δC0 + Tr<br />
2<br />
� �<br />
TATC δB0 + Tr � � �<br />
TCTB δA0<br />
+ Tr � � � �<br />
TATBTC + Tr TBTATC .<br />
The Higgs sector comprises 3 mass terms, 2 × 4 real parameters describ<strong>in</strong>g selfcoupl<strong>in</strong>gs<br />
of <strong>the</strong> bitriplets (<strong>the</strong> P structures), one parameter describ<strong>in</strong>g <strong>the</strong> selfcoupl<strong>in</strong>gs<br />
of <strong>the</strong> color s<strong>in</strong>glet, 6 real and 3 complex parameters from mix<strong>in</strong>g between<br />
<strong>the</strong> color s<strong>in</strong>glet and one of <strong>the</strong> bitriplets as well as 12 f-terms which describe mix<strong>in</strong>g<br />
between <strong>the</strong> colored scalars (<strong>the</strong> Q structures). This makes for a total of 36 real<br />
parameters.<br />
It is straightforward to solve <strong>the</strong> extremal conditions, which are given by<br />
∂V (vℓ, vu, vd)<br />
= 0 ,<br />
∂vu<br />
∂V (vℓ, vu, vd)<br />
= 0 ,<br />
∂vd<br />
∂V (vℓ, vu, vd)<br />
= 0 , (D.4)<br />
∂vℓ<br />
and can be used to elim<strong>in</strong>ate three parameters. For a general Higgs potential, it is<br />
however not possible to analytically proof that this extremum is a m<strong>in</strong>imum. The<br />
reason is, that a m<strong>in</strong>mum is only obta<strong>in</strong>ed if <strong>the</strong> Hessian of <strong>the</strong> potential is positive<br />
def<strong>in</strong>ite. The potential will however give rise to 8 + 4 Goldstone bosons, which<br />
correspond to zeros on <strong>the</strong> diagonal of <strong>the</strong> Hessian (<strong>in</strong> blockdiagonal form). As a<br />
consequence it is a numerical problem to m<strong>in</strong>imize <strong>the</strong> potential. <strong>On</strong>e can fur<strong>the</strong>r<br />
constra<strong>in</strong> <strong>the</strong> parameter space by <strong>the</strong> condition that all masses are positive, and that<br />
<strong>the</strong> vacuum value of <strong>the</strong> potential signals a local m<strong>in</strong>imum, V (vℓ, vu, vd) > V (0, 0, 0)<br />
[243].