B and L at the SUSY Scale, Dark Matter and R-parity Violation

We present a simple theory where baryon and lepton numbers are spontaneously broken at the supersymmetry scale. In this context R-parity must be spontaneously broken but the theory still contains a stable field which can play the role of the cold dark matter of the Universe. We discuss the spectrum of the theory, the properties of the dark matter candidate and the predictions for direct detection experiments. This theory provides a concrete example of exotic supersymmetric signatures associated with having the simultaneous presence of R-parity violating and missing energy signals at the Large Hadron Collider

Minimal gauged U(1)_{B-L} model with spontaneous R-parity violation

We study the minimal gauged U(1)_{B-L} supersymmetric model and show that it provides an attractive theory for spontaneous R-parity violation. Both U(1)_{B-L} and R-parity are broken by the vacuum expectation value of the right-handed sneutrino (proportional to the soft SUSY masses), thereby linking the B-L and soft SUSY scales. In this context we find a consistent mechanism for generating neutrino masses and a realistic mass spectrum, all without extending the Higgs sector of the minimal supersymmetry standard model. We discuss the most relevant collider signals and the connection between the Z' gauge boson and R-parity violation.Comment: 4 pages, new title, to appear in Physical Review Letter

Higgs boson decays, baryon number violation, and supersymmetry at the LHC

Baryon number violating interactions could modify the signatures of supersymmetric models at the Large Hadron Collider. In this article we investigate the predictions for the Higgs mass and the Higgs decays in a simple extension of the minimal supersymmetric standard model where the local baryon and lepton numbers are spontaneously broken at the TeV scale. This theory predicts baryon number violation at the low scale which can change the current LHC bounds on the supersymmetric spectrum. Using the ATLAS and CMS bounds on the Higgs mass we show the constraints on the sfermion masses, and show the subsequent predictions for the radiative Higgs decays. We found that the Higgs decay into two photons is suppressed due to the existence of new light leptons. In this theory the stops can be very light in agreement with all experimental bounds and we make a brief discussion of the possible signals at the LHC

Running with Triplets: How Slepton Masses Change With Doubly-Charged Higgses

We examine the slepton masses of SUSYLR models and how they change due the presence of light-doubly charged higgs bosons. We discover that the measurement of the slepton masses could bound and even predict the value of the third generation Yukawa coupling of leptons to the SU(2)_R Triplets. We also consider the unification prospects for this model with the addition of left-handed, B - L = 0 triplets--a model we call the Triplet Extended Supersymmetric Standard Model (TESSM). Finally, we discuss the changes in the slepton masses due to the presence of the SU(2)_L triplets.Comment: 20 pages, 6 figures, 4 table

Gauge Mediated SUSY Breaking via Seesaw

We present a simple scenario for gauge mediated supersymmetry breaking where the messengers are also the fields that generate neutrino masses. We show that the simplest such scenario corresponds to the case where neutrino masses are generated through the Type I and Type III seesaw mechanisms. The entire supersymmetric spectrum and Higgs masses are calculable from only four input parameters. Since the electroweak symmetry is broken through a doubly radiative mechanism, meaning a nearly zero B-term at the messenger scale which runs down to acceptable values, one obtains quite a constrained spectrum for the supersymmetric particles whose properties we describe. We refer to this mechanism as "nu-GMSB".Comment: a few corrections, references adde

Electromechanical Reliability Testing of Three-Axial Silicon Force Sensors

This paper reports on the systematic electromechanical characterization of a new three-axial force sensor used in dimensional metrology of micro components. The siliconbased sensor system consists of piezoresistive mechanicalstress transducers integrated in thin membrane hinges supporting a suspended flexible cross structure. The mechanical behavior of the fragile micromechanical structure isanalyzed for both static and dynamic load cases. This work demonstrates that the silicon microstructure withstands static forces of 1.16N applied orthogonally to the front-side of the structure. A statistical Weibull analysis of the measured data shows that these values are significantly reduced if the normal force is applied to the back of the sensor. Improvements of the sensor system design for future development cycles are derived from the measurement results.Comment: Submitted on behalf of TIMA Editions (http://irevues.inist.fr/tima-editions

Spontaneous R-Parity Breaking in SUSY Models

We investigate a mechanism for spontaneous R-parity breaking in a class of extensions of the minimal supersymmetric standard model with an extra Abelian gauge symmetry which is a linear combination of B-L and weak hypercharge. Both U(1)_X and R-parity are broken by the vacuum expectation value of the right-handed sneutrinos which is proportional to the soft SUSY masses. In these models the mechanism for spontaneous R-parity violation can be realized even with positive soft masses. In this context one has a realistic mechanism for generating neutrino masses as well as a realistic spectrum. We briefly discuss the possible collider signals which could be used to test the theory, the contributions for proton decay and the possibility of a gravitino as a dark matter candidate.Comment: 9 pages, typos corrected, to appear in Physical Review

A genome-wide association study identifies a susceptibility locus for biliary atresia on 2p16.1 within the gene EFEMP1

Biliary atresia (BA) is a rare pediatric cholangiopathy characterized by fibrosclerosing obliteration of the extrahepatic bile ducts, leading to cholestasis, fibrosis, cirrhosis, and eventual liver failure. The etiology of BA remains unknown, although environmental, inflammatory, infectious, and genetic risk factors have been proposed. We performed a genome-wide association study (GWAS) in a European-American cohort of 343 isolated BA patients and 1716 controls to identify genetic loci associated with BA. A second GWAS was performed in an independent European-American cohort of 156 patients with BA and other extrahepatic anomalies and 212 controls to confirm the identified candidate BA-associated SNPs. Meta-analysis revealed three genome-wide significant BA-associated SNPs on 2p16.1 (rs10865291, rs6761893, and rs727878; P < 5 ×10-8), located within the fifth intron of the EFEMP1 gene, which encodes a secreted extracellular protein implicated in extracellular matrix remodeling, cell proliferation, and organogenesis. RNA expression analysis showed an increase in EFEMP1 transcripts from human liver specimens isolated from patients with either BA or other cholestatic diseases when compared to normal control liver samples. Immunohistochemistry demonstrated that EFEMP1 is expressed in cholangiocytes and vascular smooth muscle cells in liver specimens from patients with BA and other cholestatic diseases, but it is absent from cholangiocytes in normal control liver samples. Efemp1 transcripts had higher expression in cholangiocytes and portal fibroblasts as compared with other cell types in normal rat liver. The identification of a novel BA-associated locus, and implication of EFEMP1 as a new BA candidate susceptibility gene, could provide new insights to understanding the mechanisms underlying this severe pediatric disorder