Probing the nucleon at large momentum tramsfer

The central role of soft nucleon matrix elements in reactions of high energy electrons or real photons with nucleons is emphasized. These soft matrix elements are described in terms of skewed parton distributions. Their connections to ordinary parton distributions, form factors, Compton scattering and hard meson electroproduction is discussed.Comment: 11 pages, 12 Postscript figures, fleqn, espcrc1, epsfi

Scattering of massive W bosons into gravitinos and tree unitarity in broken supergravity

The WW scattering into gravitino and gaugino is here investigated in the broken phase, by using both gauge and mass eigenstates. Differently from what is obtained for unbroken gauge symmetry, we find in the scattering amplitudes new structures, which can lead to violation of unitarity above a certain scale. This happens because, in the annihilation diagram, the longitudinal degrees of freedom in the propagator of the gauge bosons disappear from the amplitude, by virtue of the SUGRA vertex. We show that the longitudinal polarizations of the on-shell W become strongly interacting in the high energy limit, and that the inclusion of diagrams with off-shell scalars of the MSSM does not cancel the divergences.Comment: 26 pages, 17 figures. Uses JHEP3.cls, epsfig.sty and axodraw.sty. Some references, together with Ward identities in the basis of mass eigenstates, have been added. Version accepted for publication in JHE

Geographic distribution, age pattern and sites of lesions in a cohort of buruli ulcer patients from the mapé basin of cameroon

Buruli ulcer (BU), a neglected tropical disease of the skin, caused by Mycobacterium ulcerans, occurs most frequently in children in West Africa. Risk factors for BU include proximity to slow flowing water, poor wound care and not wearing protective clothing. Man-made alterations of the environment have been suggested to lead to increased BU incidence. M. ulcerans DNA has been detected in the environment, water bugs and recently also in mosquitoes. Despite these findings, the mode of transmission of BU remains poorly understood and both transmission by insects or direct inoculation from contaminated environment have been suggested. Here, we investigated the BU epidemiology in the Mapé basin of Cameroon where the damming of the Mapé River since 1988 is believed to have increased the incidence of BU. Through a house-by-house survey in spring 2010, which also examined the local population for leprosy and yaws, and continued surveillance thereafter, we identified, till June 2012, altogether 88 RT-PCR positive cases of BU. We found that the age adjusted cumulative incidence of BU was highest in young teenagers and in individuals above the age of 50 and that very young children (>5) were underrepresented among cases. BU lesions clustered around the ankles and at the back of the elbows. This pattern neither matches any of the published mosquito biting site patterns, nor the published distribution of small skin injuries in children, where lesions on the knees are much more frequent. The option of multiple modes of transmission should thus be considered. Analyzing the geographic distribution of cases in the Mapé Dam area revealed a closer association with the Mbam River than with the artificial lake

Signatures of Axinos and Gravitinos at Colliders

The axino and the gravitino are well-motivated candidates for the lightest supersymmetric particle (LSP) and also for cold dark matter in the Universe. Assuming that a charged slepton is the next-to-lightest supersymmetric particle (NLSP), we show how the NLSP decays can be used to probe the axino LSP scenario in hadronic axion models as well as the gravitino LSP scenario at the Large Hadron Collider and the International Linear Collider. We show how one can identify experimentally the scenario realized in nature. In the case of the axino LSP, the NLSP decays will allow one to estimate the value of the axino mass and the Peccei-Quinn scale.Comment: 20 pages, 5 figures, revised version as published in Phys.Lett.B (comments on the experimental feasibility added

Supergravity at Colliders

We consider supersymmetric theories where the gravitino is the lightest superparticle (LSP). Assuming that the long-lived next-to-lightest superparticle (NSP) is a charged slepton, we investigate two complementary ways to prove the existence of supergravity in nature. The first is based on the NSP lifetime which in supergravity depends only on the Planck scale and the NSP and gravitino masses. With the gravitino mass inferred from kinematics, the measurement of the NSP lifetime will test an unequivocal prediction of supergravity. The second way makes use of the 3-body NSP decay. The angular and energy distributions and the polarizations of the final state photon and lepton carry the information on the spin of the gravitino and on its couplings to matter and radiation.Comment: 13 pages, 11 figures; v2: 3 references added, to appear in Physics Letters

Semiautomated SD-OCT Measurements of Corneal Sublayer Thickness in Normal and Post-SMILE Eyes

Purpose:To test the reliability of a novel algorithm for measuring corneal epithelial thickness (ET) and stromal thickness of normal eyes and post-small incision lenticule extraction (SMILE) corneas with spectral-domain optical coherence tomography.Methods:In this prospective observational study, a customized semiautomated software algorithm was developed and applied to measure corneal ET and stromal thickness along the horizontal corneal meridian. Measurements were performed by 2 examiners in a randomized fashion on a sample of 40 eyes with previous SMILE for treatment of myopia and a control group composed of 40 normal eyes. The intrauser repeatability and interuser reproducibility were analyzed by calculating typical indices including the coefficient of variation and intraclass correlation coefficient. Corneal sublayer thickness profiles were compared between normal and post-SMILE eyes.Results:In both groups, coefficients of variation were 3.2% or lower and intraclass correlation coefficients were 0.929 or higher indicating excellent reliability of the measurement method. Central ET was on an average 6 m greater in post-SMILE corneas (58.8 5.4 m) compared with normal eyes (52.8 +/- 4.0 m), with P < 0.01. Also, there was greater interindividual variability in ET in post-SMILE corneas and their horizontal epithelial profile seemed to show a lenticular appearance.Conclusions:Highly favorable indices of measurement reliability were achieved for this novel method of measuring corneal sublayer pachymetry not only in normal eyes but also in eyes with previous SMILE. The corneal ET profile was significantly altered in post-SMILE eyes compared with normal corneas

Implications of Catalyzed BBN in the CMSSM with Gravitino Dark Matter

We investigate gravitino dark matter scenarios in which the primordial ^6Li production is catalyzed by bound-state formation of long-lived negatively charged particles X^- with ^4He. In the constrained minimal supersymmetric Standard Model (CMSSM) with the stau^- as the X^-, the observationally inferred bound on the primordial ^6Li abundance allows us to derive a rigid lower limit on the gaugino mass parameter for a standard cosmological history. This limit can have severe implications for supersymmetry searches at the Large Hadron Collider and for the reheating temperature after inflation.Comment: 4 pages, 2 figures; note and paragraph added; references updated