B->rho pi decays, resonant and nonresonant contributions

We point out that a new contribution to B decays to three pions is relevant in explaining recent data from the CLEO and BABAR collaborations, in particular the results on quasi-two-body decays via a rho meson. We also discuss the relevance of these contribution to the measurement of CP violations.Comment: 5 pages, 2 figures, few references and minor comments adde

Production and decay of gluino pairs at hadron colliders

At hadron colliders, one of the most important channels for sparticle production is expected to be the gluino pair production. In the scenario where the sbottom is lighter than the gluino, gluinos can decay into sbottom and bottom quarks. Sbottoms can subsequently decay into bottom quarks and neutralinos. Hence, one expects a rich signature consisting of four b-jets and the missing transverse energy from neutralinos. To compute the cross section of this reaction, it is important to find tools and techniques suitable for the calculation of diagrams with many particles in the final state. We present here a way to deal with such complicated reactions.Comment: Proceedings of the Conference: "QCD and High Energy Hadronic Interactions", XXXXth Rencontres de Moriond, La Thuile, Italy - March 12-19, 2005 - 4 pages. References update

ATLAS discovery potential for a heavy charged Higgs boson

The sensitivity of the ATLAS detector to the discovery of a heavy charged Higgs boson is presented. Assuming a heavy SUSY spectrum, the most promising channels above the top quark mass are $H^\pm\to tb$ and $H^\pm\to\tau^\pm\nu_\tau$ which provide coverage in the low and high $\tan\beta$ regions up to $\sim 600$ GeV. The achievable precisions on the charged Higgs mass and $\tan\beta$ determination are also discussed. The $H^\pm\to W^\pm h^0$ channel, though restricted to a small MSSM parameter space, shows a viable signal in NMSSM where the parameter space is less constrained. The observation of the channel $H^-\to\tau^-_L\nu_\tau + c.c.$ may constitute a distinctive evidence for models with singlet neutrinos in large extra dimensions.Comment: 18 page

The exclusive B_s -> phi mu+ mu- process in a constituent quark model

We consider the exclusive B_s -> phi mu+ mu- process in the standard model using a constituent quark loop model approach together with a simple parameterization of the quark dynamics. The model allows to compute the decay form factors and therefore can give predictions for the decay rates, the invariant mass spectra and the asymmetries. This process is suppressed in the standard model but can be enhanced if new physics beyond the standard model is present, such as flavor-violating supersymmetric models. It constitutes therefore an interesting precision test of the standard model at forthcoming experiments.Comment: 17 pages, 6 figures, 5 tables, LaTeX; minor changes to the introduction, table III and figure 3. Few references adde

On the mass of the Ds(0+,1+) system

In this note we discuss a determination for the mass of the Ds(0+,1+) system recently discovered by the BaBar, CLEO II and Belle Collaborations. The value of the mass is derived by making explicit the prediction obtained in a quark-meson model prior to the discovery of these states.Comment: 3 pages, revte

Model Independent Framework for Searches of Top Partners

We propose a model-independent and general framework to study the LHC phenomenology of top partners, i.e. Vector-Like quarks including particles with different electro-magnetic charge. We consider Vector-Like quarks embedded in general representations of the weak SU(2)L, coupling to all Standard Model quarks via Yukawa mixing focusing on the case of a single multiplet. We show that, with very minimal and quite general assumptions, top partners may be studied in terms of few parameters in an effective Lagrangian description with a clear and simple connection with experimental observables. We also demonstrate that the parametrisation can be applied as well to cases with many Vector-like multiplets, thus covering most realistic models of New Physics. We perform a numerical study to understand the conclusions which can be drawn within such a description and the expected potential for discovery or exclusion at the LHC. Our main results are a clear connection between branching ratios and single production channels, and the identification of novel interesting channels to be studied at the LHC.Comment: 42 pages, 2 figures, 20 tables, added an appendix with a discussion of coupling chirality in general scenarios; added a comparison of collider and flavour bounds; added details about the range of validity of the framework. References adde