Stop Decay with LSP Gravitino in the final state: t~1→G~ W b\tilde{t}_1\to\widetilde{G}\,W\,b

In MSSM scenarios where the gravitino is the lightest supersymmetric particle (LSP), and therefore a viable dark matter candidate, the stop $\tilde{t}_1$ could be the next-to-lightest superpartner (NLSP). For a mass spectrum satisfying: $m_{\widetilde{G}}+m_t>m_{\tilde{t}_1}>m_{\widetilde{G}}+m_b+m_W$, the stop decay is dominated by the 3-body mode $\tilde{t}_1\rightarrow b\,W\,\tilde{G}$. We calculate the stop life-time, including the full contributions from top, sbottom and chargino as intermediate states. We also evaluate the stop lifetime for the case when the gravitino can be approximated by the goldstino state. Our analytical results are conveniently expressed using an expansion in terms of the intermediate state mass, which helps to identify the massless limit. In the region of low gravitino mass ($m_{\widetilde{G}}\ll m_{\tilde{t}_1}$) the results obtained using the gravitino and goldstino cases turns out to be similar, as expected. However for higher gravitino masses $m_{\widetilde{G}} \lesssim m_{\tilde{t}_1}$ the results for the lifetime could show a difference of O(100)\%

Dark Left-Right Gauge Model: SU(2)_R Phenomenology

In the recently proposed dark left-right gauge model of particle interactions, the left-handed fermion doublet $(\nu,e)_L$ is connected to its right-handed counterpart $(n,e)_R$ through a scalar bidoublet, but $\nu_L$ couples to $n_R$ only through $\phi_1^0$ which has no vacuum expectation value. The usual R parity, i.e. $R = (-)^{3B+L+2j}$, can be defined for this nonsupersymmetric model so that both $n$ and $\Phi_1$ are odd together with $W_R^\pm$. The lightest $n$ is thus a viable dark-matter candidate (scotino). Here we explore the phenomenology associated with the $SU(2)_R$ gauge group of this model, which allows it to appear at the TeV energy scale. The exciting possibility of $Z' \to 8$ charged leptons is discussed.Comment: 12 pages, 2 figure

On maximal transitive sets of generic diffeomorphisms

We construct locally generic C1-diffeomorphisms of 3-manifolds with maximal transitive Cantor sets without periodic points. The locally generic diffeomorphisms constructed also exhibit strongly pathological features general-izing the Newhouse phenomenon (coexistence of infinitely many sinks or sources). Two of these features are: coex-istence of infinitely many nontrivial (hyperbolic and nonhyperbolic) attractors and repellors, and coexistence of in-finitely many nontrivial (nonhyperbolic) homoclinic classes. We prove that these phenomena are associated to the existence of a homoclinic class H(P, f) with two spe-cific properties: – in a C1-robust way, the homoclinic class H(P, f) does not admit any dominated splitting, – there is a periodic point P ′ homoclinically related to P such that the Jacobians of P ′ and P are greater than and less than one, respectively. 1