|
| | | | |
| | | |
| Stat |
Members: 3645
Articles: 2'501'711
Articles rated: 2609
20 April 2024 |
|
| | | | |
|
Article overview
| |
|
|
Particle-Antiparticle Mixing, epsilon_K and the Unitarity Triangle in the Littlest Higgs Model | | Andrzej J. Buras
; Anton Poschenrieder
; Selma Uhlig
; | | Date: |
22 Oct 2004 | | Journal: | Nucl.Phys. B716 (2005) 173-198 | | Subject: | hep-ph | | Abstract: | We calculate the K^{0}-ar{K}^{0}, B_{d,s}^{0}-ar{B}_{d,s}^{0} mixing mass differences Delta M_K, Delta M_{d,s} and the CP-violating parameter epsilon_{K} in the Littlest Higgs (LH) model. For f/v as low as 5 and the Yukawa parameter x_L<0.8, the enhancement of Delta M_{d} amounts to at most 20%. Similar comments apply to Delta M_s and epsilon_{K}. The correction to Delta M_{K} is negligible. The dominant new contribution in this parameter range, calculated here for the first time, comes from the box diagrams with (W_L^pm,W_H^pm) exchanges and ordinary quarks that are only suppressed by the mass of W_H^pm but do not involve explicit O(v^2/f^2) factors. This contribution is strictly positive. The explicit O(v^2/f^2) corrections to the SM diagrams with ordinary quarks and two W_L^pm exchanges have to be combined with the box diagrams with a single heavy T quark exchange for the GIM mechanism to work. These O(v^2/f^2) corrections are found to be of the same order of magnitude as the (W_L^pm,W_H^pm) contribution but only for x_L approaching 0.8 they can compete with it. We point out that for x_L>0.85 box diagrams with two T exchanges have to be included. Although formally O(v^4/f^4), this contribution is dominant for x_L approx 1 due to non-decoupling of T that becomes fully effective only at this order. We emphasize, that the concept of the unitarity triangle is still useful in the LH model, in spite of the O(v^2/f^2) corrections to the CKM unitarity involving only ordinary quarks. We demonstrate the cancellation of the divergences in box diagrams that appear when one uses the unitary gauge for W_L^pm and W_H^pm. | | Source: | arXiv, hep-ph/0410309 | | Services: | Forum | Review | PDF | Favorites | |
|
|
No review found.
Did you like this article?
Note: answers to reviews or questions about the article must be posted in the forum section.
Authors are not allowed to review their own article. They can use the forum section.
browser Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)
|
| |
|
|
|
|
News, job offers and information for researchers and scientists:
| |
REGISTER