Collider signals from slow decays in supersymmetric models with an intermediate-scale solution to the mu problem

The problem of the origin of the mu parameter in the Minimal Supersymmetric Standard Model can be solved by introducing singlet supermultiplets with non-renormalizable couplings to the ordinary Higgs supermultiplets. The Peccei-Quinn symmetry is broken at a scale which is the geometric mean between the weak scale and the Planck scale, yielding a mu term of the right order of magnitude and an invisible axion. These models also predict one or more singlet fermions which have electroweak-scale masses and suppressed couplings to MSSM states. I consider the case that such a singlet fermion, containing the axino as an admixture, is the lightest supersymmetric particle. I work out the relevant couplings in several of the simplest models of this type, and compute the partial decay widths of the next-to-lightest supersymmetric particle involving leptons or jets. Although these decays will have an average proper decay length which is most likely much larger than a typical collider detector, they can occasionally occur within the detector, providing a striking signal. With a large sample of supersymmetric events, there will be an opportunity to observe these decays, and so gain direct information about physics at very high energy scales.Comment: 24 pages, LaTeX, 4 figure

The fully differential single-top-quark cross section in next-to-leading order QCD

We present a new next-to-leading order calculation for fully differential single-top-quark final states. The calculation is performed using phase space slicing and dipole subtraction methods. The results of the methods are found to be in agreement. The dipole subtraction method calculation retains the full spin dependence of the final state particles. We show a few numerical results to illustrate the utility and consistency of the resulting computer implementations.Comment: 37 pages, latex, 2 ps figure

String theoretic QCD axion with stabilized saxion and the pattern of supersymmetry breaking

String theoretic axion is a prime candidate for the QCD axion solving the strong CP problem. For a successful realization of the QCD axion in string theory, one needs to stabilize moduli including the scalar partner (saxion) of the QCD axion, while keeping the QCD axion unfixed until the low energy QCD instanton effects are turned on. We note that a simple generalization of KKLT moduli stabilization provides such set-up realizing the axion solution to the strong CP problem. Although some details of moduli stabilization are different from the original KKLT scenario, this set-up leads to the mirage mediation pattern of soft SUSY breaking terms as in the KKLT case, preserving flavor and CP as a consequence of approximate scaling and axionic shift symmetries. The set-up also gives an interesting pattern of moduli masses which might avoid the cosmological moduli, gravitino and axion problems.Comment: JHEP style, 21 pages, 3 figures; typos correcte

Multiple Interactions and the Structure of Beam Remnants

Recent experimental data have established some of the basic features of multiple interactions in hadron-hadron collisions. The emphasis is therefore now shifting, to one of exploring more detailed aspects. Starting from a brief review of the current situation, a next-generation model is developed, wherein a detailed account is given of correlated flavour, colour, longitudinal and transverse momentum distributions, encompassing both the partons initiating perturbative interactions and the partons left in the beam remnants. Some of the main features are illustrated for the Tevatron and the LHC.Comment: 69pp, 33 figure

Single Top Quark at Future Hadron Colliders. Complete Signal and Background Study

We perform a detail theoretical study including decays and jet fragmentation of all the important modes of the single top quark production and all basic background processes at the upgraded Tevatron and LHC colliders. Special attention was paid to the complete tree level calculation of the QCD fake background which was not considered in the previous studies. Analysis of the various kinematical distributions for the signal and backgrounds allowed to work out a set of cuts for an efficient background suppression and extraction of the signal. It was shown that the signal to background ratio after optimized cuts could reach about 0.4 at the Tevatron and 1 at the LHC. The remaining after cuts rate of the signal at the LHC for the $lepton+jets$ signature is expected to be about 6.1 pb and will be enough to study the single top physics even during the LHC operation at a low luminosity.Comment: 15 pages, LaTex, 7 figure

Extensive Air Showers from Ultra High Energy Gluinos

We study the proposal that the cosmic ray primaries above the Greisen-Zatsepin-Kuzmin (GZK) cutoff are gluino-containing hadrons ($\tilde g$-hadrons). We describe the interaction of $\tilde g$-hadrons with nucleons in the framework of the Gribov-Regge approach using a modified version of the hadronic interaction model QGSJET for the generations of Extensive Air Showers (EAS). There are two mass windows marginally allowed for gluinos: m_{\tilde g}\lsim 3 GeV and 25\lsim m_{\tilde g}\lsim 35 GeV. Gluino-containing hadrons corresponding to the second window produce EAS very different from the observed ones. Light $\tilde g$-hadrons corresponding to the first gluino window produce EAS similar to those initiated by protons, and only future detectors can marginally distinguish them. We propose a beam-dump accelerator experiment to search for $\tilde g$-hadrons in this mass window. We emphasize the importance of this experiment: it can discover (or exclude) the light gluino and its role as a cosmic ray primary at ultra high energies.Comment: 27 pages latex, 13 eps figure

Interaction of inflammatory cytokines and erythropoeitin in iron metabolism and erythropoiesis in anaemia of chronic disease

In chronic inflammatory conditions increased endogenous release of specific cytokines (TNFα, IL-1, IL-6, IFNγ and others) is presumed. It has been shown that those of monocyte lineage play a key role in cytokine expression and synthesis. This may be associated with changes in iron metabolism and impaired erythropoiesis and may lead to development of anaemia in patients with rheumatoid arthritis. Firstly, increased synthesis of acute phase proteins, like ferritin, during chronic inflammation is proposed as the way by which the toxic effect of iron and thereby the synthesis of free oxy-radicals causing the damage on the affected joints, may be reduced. This is associated with a shift of iron towards the mononuclear phagocyte system which may participate in the development of anaemia of chronic disease. Secondly, an inhibitory action of inflammatory cytokines (TNFα, IL-1), on proliferation and differentiation of erythroid progenitors as well as on synthesis of erythropoietin has been shown, thereby also contributing to anaemia. Finally, chronic inflammation causes multiple, complex disturbances in the delicate physiologic equilibrium of interaction between cytokines and cells (erythroid progenitors, cells of mononuclear phagocyte system and erythropoietin producing cells) leading to development of anaemia of chronic disease (Fig. 1)

Search for Supersymmetry in Di-Photon Final States at sqrt{s} = 1.96 TeV

We report results of a search for supersymmetry (SUSY) with gauge-mediated symmetry breaking in di-photon events collected by the D0 experiment at the Fermilab Tevatron Collider in 2002--2006. In 1.1 fb$^{-1}$ of data, we find no significant excess beyond the background expected from the standard model and set the most stringent lower limits to date for a standard benchmark model on the lightest neutralino and chargino masses of 125 GeV and 229 GeV, respectively, at 95% confidence