Soft supersymmetry-breaking terms from supergravity and superstring models

We review the origin of soft supersymmetry-breaking terms in N=1 supergravity models of particle physics. We first consider general formulae for those terms in general models with a hidden sector breaking supersymmetry at an intermediate energy scale. The results for some simple models are given. We then consider the results obtained in some simple superstring models in which particular assumptions about the origin of supersymmetry breaking are made. These are models in which the seed of supersymmetry breaking is assumed to be originated in the dilaton/moduli sector of the theory.Comment: 24 pages, to appear in the book `Perspectives on Supersymmetry', World Scientific, Editor G. Kane; some comments and references adde

Challenges for MSSM Higgs searches at Hadron Colliders

In this article we analyze the impact of B-physics and Higgs physics at LEP on standard and non-standard Higgs bosons searches at the Tevatron and the LHC, within the framework of minimal flavor violating supersymmetric models. The B-physics constraints we consider come from the experimental measurements of the rare B-decays b -> s gamma and B_u -> tau nu and the experimental limit on the B_s -> mu+ mu- branching ratio. We show that these constraints are severe for large values of the trilinear soft breaking parameter A_t, rendering the non-standard Higgs searches at hadron colliders less promising. On the contrary these bounds are relaxed for small values of A_t and large values of the Higgsino mass parameter mu, enhancing the prospects for the direct detection of non-standard Higgs bosons at both colliders. We also consider the available ATLAS and CMS projected sensitivities in the standard model Higgs search channels, and we discuss the LHC's ability in probing the whole MSSM parameter space. In addition we also consider the expected Tevatron collider sensitivities in the standard model Higgs h -> b bbar channel to show that it may be able to find 3 sigma evidence in the B-physics allowed regions for small or moderate values of the stop mixing parameter.Comment: 22 pages, 5 figures. Added references and acknowledgements. Submitted to PR

Proton Stability and Dark Matter in a Realistic String MSSM

We demonstrate the existence of an extra nonanomalous U(1) gauge symmetry in a three-generation Pati-Salam model constructed with intersecting D6-branes in Type IIA string theory on a T^6/(Z_2 \times Z_2) orientifold. This extra U(1) forbids all dimension-4, 5, and 6 operators which mediate proton decay in the MSSM. Moreover, this results in the effective promotion of baryon and lepton number to local gauge symmetries, which can potentially result in leptophobic and leptophilic $Z'$ bosons observable at the LHC. Furthermore, it is not necessary to invoke R-parity to forbid the dimension-4 operators which allow rapid proton decay. However, R-parity may arise naturally from a spontaneously broken U(1)_{B-L}. Assuming the presence of R-parity, we then study the direct detection cross-sections for neutralino dark matter, including the latest constraints from the XENON100 experiment. We find that these limits are now within required range necessary to begin testing the model.Comment: Expanded discussion of Z' boson phenomenology. Accepted for publication to Physical Review D. arXiv admin note: text overlap with arXiv:1103.603

Goldstino and sgoldstino in microscopic models and the constrained superfields formalism

We examine the exact relation between the superconformal symmetry breaking chiral superfield (X) and the goldstino superfield in microscopic models of an arbitrary Kahler potential (K) and in the presence of matter fields. We investigate the decoupling of the massive sgoldstino and scalar matter fields and the offshell/onshell-SUSY expressions of their superfields in terms of the fermions composites. For general K of two superfields, we study the properties of the superfield X after integrating out these scalar fields, to show that in the infrared it satisfies (offshell) the condition $X^3=0$ and $X^2\not=0$. We then compare our results to those of the well-known method of constrained superfields discussed in the literature, based on the conjecture $X^2=0$. Our results can be used in applications, to couple offshell the (s)goldstino fields to realistic models such as the MSSM.Comment: 24 page

On non-universal Goldstino couplings to matter

Using the constrained superfields formalism to describe the interactions of a light goldstino to matter fields in supersymmetric models, we identify generalised, higher-order holomorphic superfield constraints that project out the superpartners and capture the non-universal couplings of the goldstino to matter fields. These arise from microscopic theories in which heavy superpartners masses are of the order of the supersymmetry breaking scale (\sqrt f). In the decoupling limit of infinite superpartners masses, these constraints reduce to the familiar, lower-order universal constraints discussed recently, that describe the universal goldstino-matter fields couplings, suppressed by inverse powers of \sqrt f. We initiate the study of the couplings of the Standard Model (SM) fields to goldstino in the constrained superfields formalism.Comment: 28 pages; one comment adde

Determining the Structure of Supersymmetry-Breaking with Renormalization Group Invariants

If collider experiments demonstrate that the Minimal Supersymmetric Standard Model (MSSM) is a good description of nature at the weak scale, the experimental priority will be the precise determination of superpartner masses. These masses are governed by the weak scale values of the soft supersymmetry (SUSY)-breaking parameters, which are in turn highly dependent on the SUSY-breaking scheme present at high scales. It is therefore of great interest to find patterns in the soft parameters that can distinguish different high scale SUSY-breaking structures, identify the scale at which the breaking is communicated to the visible sector, and determine the soft breaking parameters at that scale. In this work, we demonstrate that 1-loop Renormalization Group~(RG) invariant quantities present in the MSSM may be used to answer each of these questions. We apply our method first to generic flavor-blind models of SUSY-breaking, and then examine in detail the subset of these models described by General Gauge Mediation and the constrained MSSM with non-universal Higgs masses. As RG invariance generally does not hold beyond leading-log order, we investigate the magnitude and direction of the 2-loop corrections. We find that with superpartners at the TeV scale, these 2-loop effects are either negligible, or they are of the order of optimistic experimental uncertainties and have definite signs, which allows them to be easily accounted for in the overall uncertainty.Comment: v2 -- references added, version to be published in PRD; 40 page

Nonlinear Realizations of Supersymmetry and Other Symmetries

Simultaneous nonlinear realizations of spontaneously broken supersymmetry in conjunction with other spontaneous and/or explicitly broken symmetries including R symmetry, global chiral symmetry, dilatations and the superconformal symmetries is reviewed.Comment: 15 pages, invited brief review for Mod. Phys. Lett.

Effects of an intermediate scale in SUSY grand unification

We discuss the production of lepton flavor violation and EDMs and the viability of the $b-\tau$ unification hypothesis in SUSY grand unification with an intermediate gauge symmetry breaking scale.Comment: 3 pages (Latex, esprc2.sty used), talk given at 4th International Conference on Supersymmetry (SUSY '96, College Park, MD, May 29 - June 1, 1996

Phase equilibria in sugar solutions using the A-UNIFAC model

http://apps.isiknowledge.com/full_record.do?product=UA&search_mode=GeneralSearch&qid=2&SID=V21Di6PajaHLPoM3@AJ&page=1&doc=1&colname=WOSIn this work, a modified UNIFAC model that explicitly takes into account association effects is used to describe the thermodynamic properties of phase equilibria of mixtures containing common sugars, alcohols, and water. Three main groups were defined to represent the sugars family: the sugar ring (pyranose and furanose), the osidic bond (-O-), and the hydroxyl ring group (OHring). For the association term, a general two-site OH associating group is used to represent association effects in these solutions, allowing a straightforward extension to multicomponent mixtures. Correlation of both solvent properties (osmotic coefficients, water activities, vapor pressures, and boiling and freezing points of binary aqueous sugar solutions) and sugar solubility in water and alcohols gives very accurate results. Good predictions are obtained for vapor-liquid equilibrium and solid-liquid equilibrium of ternary and quaternary mixtures of sugars in mixed solvents.O.F. acknowledges financial support from the PRAXIS program, FCT, Lisbon, Portugal

Application of the GCA-EoS model to the supercritical processing of fatty oil derivatives

The group-contribution with association equation of state (GCA-EoS) is applied to represent high-pressure phase equilibria in mixtures of supercritical gases (carbon dioxide, propane) with fatty oil derivatives, such as mono- and di-glycerides, fatty acids and fatty acid esters. Association effects in these mixtures are described by a group-contribution approach using three different association groups: the hydroxyl group, the acid group and the ester group. Satisfactory predictions of vapor–liquid equilibria, liquid–liquid equilibria and c1 of binary and ternary mixtures of high-molecular weight triacyglycerides and their derivatives with carbon dioxide or propane are obtained. It is shown that the GCA-EoS is a powerful engineering tool for the design and optimization of extraction and fractionation processes of fatty oil derivatives with supercritical fluids.Olga Ferreira acknowledges PRAXIS program, FCT, Lisbon, Portugal (SFRH/BD/879/2000). E.A. Brignole acknowledges financial support from CONICET, Argentina and the Universidad Nacional del Sur