Flavor Changing Neutral Current Effects and CP Violation in the Minimal 3-3-1 Model

We investigate in detail the flavor structure of the minimal 331 model and its implications for several flavor changing neutral current (FCNC) processes. In this model, where the weak SU(2)_L gauge group of the Standard Model is extended to a SU(3)_L, the by far dominant new contributions come from an additional neutral Z' gauge boson, that can transmit FCNCs at tree-level. At the same time, electroweak precision observables receive new contributions only at the loop level and do not constrain the model very strongly. In our analysis, we take into account new CP violating effects that have been neglected in earlier analyses, and account for a general flavor structure without reference to a certain parameterization of the new mixing matrix. We begin by studying the bounds obtained from quantities such as Delta M_K, epsilon_K, Delta M_{d/s} as well as sin 2 beta|_{J/psi K_S}, and go on to explore the implications for several clean rare decay channels, namely the decays K+->pi+ nu nu, K_L -> pi0 nu nu, B_{d/s} -> mu+ mu- and K_L -> pi0 l+l-. We find sizeable effects in all these decays, but the most interesting quantity turns out to be the B_s - bar B_s mixing phase beta_s, as measured in the mixing induced CP asymmetry of B_s -> J/psi phi, which can be large. In general, we find effects in purely hadronic channels to be larger than in (semi-)leptonic ones, due to a suppression of the Z'-lepton couplings.Comment: 29 pages, 11 figures, Some Comments and References added, version to appear in Phys Rev

Bankenregulierung und Regulierung von Informationsveröffentlichung bei M&A

Regulation is indispensable for the functioning of financial markets. After a decade of deregulation, financial regulation has come back into the focus of political discussion. This work reviews the effectiveness of existing and need for new regulation in two exemplary empirical studies. The first part shows that the introduction of bank bankruptcy regulation to deal with banks in financial distress in Germany and the UK has, at best, been marginally effective. It mainly affects credit holders through the withdrawal of implicit bail-out guarantees, with no effect on equity holders. The second part studies information disclosure in the case of M&A. It is shown that the disclosure of additional information at announcement, in this case synergy estimates, is highly relevant for investors. In spite of this fact regulation is discouraged, as the optimal amount of information is best determined by capital markets through managers diligently weighing the costs and benefits of disclosure.Regulierung ist unabdingbar für das Funktionieren von Kapitalmärkten, und nach einer mehrjährigen Phase der Deregulierung wieder Gegenstand intensiver politischer Diskussion. Die Arbeit überprüft an zwei empirischen Beispielen die Effektivität bestehender und die Notwendigkeit zur Einführung erweiterter Regulierung. Im ersten Teil wird festgestellt, dass die Einführung von Regulierung zur Restrukturierung von Banken in Insolvenzgefahr in Deutschland und Großbritannien nur geringe Wirksamkeit und begrenzte Auswirkungen auf den Kapitalmarkt, insbesondere für Schuldner, hatte. Im zweiten Teil wird die Notwendigkeit der Regulierung von Informationsveröffentlichung im Fall von Mergers (M&A) untersucht. Es wird festgestellt, dass die Veröffentlichung zusätzlicher Informationen hochrelevant für Investoren ist. Trotzdem wird von einer Regulierung dieser Veröffentlichungen abgeraten, da die Bestimmung der optimalen Informationsmenge idealerweise am Kapitalmarkt erfolgt