8,875 research outputs found

### Flavor SU(3) analysis of charmless B->PP decays

We perform a global fits to charmless $B \to PP$ decays which independently
constrain the $(\bar\rho,\bar\eta)$ vertex of the unitarity triangle. The
fitted amplitudes and phase are used to predict the branching ratios and CP
asymmetries of all decay modes, including those of the $B_s$ system. Different
schemes of SU(3) breaking in decay amplitude sizes are analyzed. The
possibility of having a new physics contribution to $K \pi$ decays is also
discussed.Comment: 3 pages, 2 figs. Talk given at EPS-HEP07 To appear in the
proceedings, Reference adde

### U-Spin Tests of the Standard Model and New Physics

Within the standard model, a relation involving branching ratios and direct
CP asymmetries holds for the B-decay pairs that are related by U-spin. The
violation of this relation indicates new physics (NP). In this paper, we assume
that the NP affects only the Delta S = 1 decays, and show that the NP operators
are generally the same as those appearing in B -> pi K decays. The fit to the
latest B -> pi K data shows that only one NP operator is sizeable. As a
consequence, the relation is expected to be violated for only one decay pair:
Bd -> K0 pi0 and Bs -> Kbar0 pi0.Comment: 12 pages, latex, no figures. References changed to follow MPL
guidelines; info added about U-spin breaking and small NP strong phases;
discussion added about final-state pi-K rescattering; analysis and
conclusions unaltere

### Two-loop Barr-Zee type Contributions to $(g-2)_\mu$ in the MSSM

We consider the contribution of a two-loop Barr-Zee type diagram to
$(g-2)_\mu$ in the minimal supersymmetric standard model (MSSM). At relatively
large $\tan\beta$, we show that the contribution of light third generation
scalar fermions and neutral CP-even Higgs, $h^0(H^0)$, can easily explain the
very recent BNL experimental data. In our analysis $(g-2)_\mu$ prefers negative
$A_{f}$ and positive $\mu$. It is more sensitive to the chirality flipping
h^0(H^0)\wt{f}_R^*\wt{f}_L rather than chirality conserving couplings.Comment: 10 pages, 5 figures, references adde

### B_{s,d} -> l^+ l^- and K_L -> l^+ l^- in SUSY models with non-minimal sources of flavour mixing

We present a general analysis of B_{s,d}-> l^+ l^- and K_L -> l^+ l^- decays
in supersymmetric models with non-minimal sources of flavour mixing. In spite
of the existing constraints on off-diagonal squark mass terms, these modes
could still receive sizeable corrections, mainly because of Higgs-mediated
FCNCs arising at large tan(beta). The severe limits on scenarios with large
tan(beta) and non-negligible {tilde d}^i_{R(L)}-{d-tilde}^j_{R(L)} mixing
imposed by the present experimental bounds on these modes and Delta B=2
observables are discussed in detail. In particular, we show that scalar-current
contributions to K_L -> l^+ l^- and B-{bar B} mixing set non-trivial
constraints on the possibility that B_s -> l^+ l^- and B_d -> l^+ l^- receive
large corrections.Comment: 18 pages, 4 figures (v2: minor changes, published version

### Molecular transistor coupled to phonons and Luttinger-liquid leads

We study the effects of electron-phonon interactions on the transport
properties of a molecular quantum dot coupled to two Luttinger-liquid leads. In
particular, we investigate the effects on the steady state current and DC noise
characteristics. We consider both equilibrated and unequilibrated on-dot
phonons. The density matrix formalism is applied in the high temperature
approximation and the resulting semi-classical rate equation is numerically
solved for various strengths of electron-electron interactions in the leads and
electron-phonon coupling. The current and the noise are in general smeared out
and suppressed due to intralead electron interaction. On the other hand, the
Fano factor, which measures the noise normalized by the current, is more
enhanced as the intralead interaction becomes stronger. As the electron-phonon
coupling becomes greater than order one, the Fano factor exhibits
super-Poissonian behaviour.Comment: 11 pages, 11 figure

### MACS: Multi-agent COTR system for Defense Contracting

The field of intelligent multi-agent systems has expanded rapidly in the recent past. Multi-agent architectures and systems are being investigated and continue to develop. To date, little has been accomplished in applying multi-agent systems to the defense acquisition domain. This paper describes the design, development, and related considerations of a multi-agent system in the area of procurement and contracting for the defense acquisition community

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