Direct Detection of Non-Chiral Dark Matter

Direct detection experiments rule out fermion dark matter that is a chiral representation of the electroweak gauge group. Non-chiral real, complex and singlet representations, however, provide viable fermion dark matter candidates. Although any one of these candidates will be virtually impossible to detect at the LHC, it is shown that they may be detected at future planned direct detection experiments. For the real case, an irreducible radiative coupling to quarks may allow a detection. The complex case in general has an experimentally ruled out tree-level coupling to quarks via Z-boson exchange. However, in the case of two SU(2)_L doublets, a higher dimensional coupling to the Higgs can suppress this coupling, and a remaining irreducible radiative coupling may allow a detection. Singlet dark matter could be detected through a coupling to quarks via Higgs exchange. Since all non-chiral dark matter can have a coupling to the Higgs, at least some of its mass can be obtained from electroweak symmetry breaking, and this mass is a useful characterization of its direct detection cross-section.Comment: 22 pages, 3 figures. References added. Minor corrections to match published versio

First Direct Detection Limits on sub-GeV Dark Matter from XENON10

The first direct detection limits on dark matter in the MeV to GeV mass range are presented, using XENON10 data. Such light dark matter can scatter with electrons, causing ionization of atoms in a detector target material and leading to single- or few-electron events. We use 15 kg-days of data acquired in 2006 to set limits on the dark-matter-electron scattering cross section. The strongest bound is obtained at 100 MeV where sigma_e < 3 x 10^{-38} cm^2 at 90% CL, while dark matter masses between 20 MeV and 1 GeV are bounded by sigma_e < 10^{-37} cm^2 at 90% CL. This analysis provides a first proof-of-principle that direct detection experiments can be sensitive to dark matter candidates with masses well below the GeV scale.Comment: Submitted to PR

An Electron Fixed Target Experiment to Search for a New Vector Boson A' Decaying to e+e-

We describe an experiment to search for a new vector boson A' with weak coupling alpha' > 6 x 10^{-8} alpha to electrons (alpha=e^2/4pi) in the mass range 65 MeV < m_A' < 550 MeV. New vector bosons with such small couplings arise naturally from a small kinetic mixing of the "dark photon" A' with the photon -- one of the very few ways in which new forces can couple to the Standard Model -- and have received considerable attention as an explanation of various dark matter related anomalies. A' bosons are produced by radiation off an electron beam, and could appear as narrow resonances with small production cross-section in the trident e+e- spectrum. We summarize the experimental approach described in a proposal submitted to Jefferson Laboratory's PAC35, PR-10-009. This experiment, the A' Experiment (APEX), uses the electron beam of the Continuous Electron Beam Accelerator Facility at Jefferson Laboratory (CEBAF) at energies of ~1-4 GeV incident on 0.5-10% radiation length Tungsten wire mesh targets, and measures the resulting e+e- pairs to search for the A' using the High Resolution Spectrometer and the septum magnet in Hall A. With a ~1 month run, APEX will achieve very good sensitivity because the statistics of e+e- pairs will be ~10,000 times larger in the explored mass range than any previous search for the A' boson. These statistics and the excellent mass resolution of the spectrometers allow sensitivity to alpha'/alpha one to three orders of magnitude below current limits, in a region of parameter space of great theoretical and phenomenological interest. Similar experiments could also be performed at other facilities, such as the Mainz Microtron.Comment: 19 pages, 12 figures, 2 table

Abdominaler Schmerz

Zusammenfassung: Abdominalschmerzen können Ausdruck einer Vielzahl intra- und extraabdomineller Erkrankungen sein. Angesichts dieses breiten ätiologischen Spektrums gilt es, im Initialstadium der Diagnostik zielgerichtet vorzugehen, um ohne Zeitverzug die Ursache und damit letzlich die Dringlichkeit weitergehender Maßnahmen zu bestimmen. Ziel dieser Evaluation ist eine initiale risikostratifizierte Triagierung des Patienten. Im Gegensatz zu somatischen Ursachen abdominalen Schmerzes ist eine derartige kausale Therapie bei funktionellen Erkrankungen des Gastrointestinaltraktes zum gegenwärtigen Zeitpunkt nur sehr begrenzt möglich, sodass hierbei der Fokus auf eine bedarfs- und symptomadaptierte Behandlung gelegt werden sol

Rotator cuff tears after 70years of age: A prospective, randomized, comparative study between decompression and arthroscopic repair in 154 patients

SummaryIntroductionArthroscopic repair of rotator cuff tears leads to better clinical outcomes than subacromial decompression alone; however the former is rarely proposed to patients above 70years of age. Our hypothesis was that arthroscopic repair would be superior to decompression in patient 70years or older. The primary goal was to compare the clinical results obtained with each technique. The secondary goal was to analyze the effects of age, tendon retraction and fatty infiltration on the outcome.MethodsThis was a prospective, comparative, randomized, multicenter study where 154 patients were included who were at least 70years of age. Of the included patients, 143 (70 repair and 73 decompression) were seen at one-year follow-up; these patients had an average age of 74.6years. Shoulders had a complete supraspinatus tear with extension limited to the upper-third of the infraspinatus and Patte stage 1 or 2 retraction. Clinical outcomes were evaluated with the Constant, ASES and SST scores.ResultsAll scores improved significantly with both techniques: Constant +33.81 (P<0.001), ASES +52.1 (P<0.001), SST +5.86 (P<0.001). However, repair led to even better results than decompression: Constant (+35.85 vs. +31.8, P<0.05), ASES (+56.09 vs. +48.17, P=0.01), SST (+6.33 vs. +5.38, P=0.02). The difference between repair and decompression was not correlated with age; arthroscopic repair was also better in patients above 75years of age (Constant, ASES and SST scores P<0.01). There was no significant correlation between the final outcomes and initial retraction: Constant (P=0.14), ASES (P=0.92), SST (P=0.47). The difference between repair and decompression was greater in patients with stages 0 and 1 fatty infiltration (Constant P<0.02) than in patients with stages 2 and 3 fatty infiltration (Constant P<0.05).ConclusionThere was a significant improvement in all-clinical scores for both techniques 1year after surgery. Repair was significantly better than decompression for all clinical outcomes, even in patients above 75years of age. The difference observed between repair and decompression was greater in patients with more retracted tears and lesser in patients with more severe fatty infiltration.Level of proofII (prospective, randomized study with low power)

Molecule Microscopy

Contains research objectives and reports on seven research projects.Whitaker Health Sciences FundFrancis L. Friedman ChairNational Institutes of Health (Grant AM-31546)National Institutes of Health (Grant AM-25535)International Business Machines, Inc

Lumbar Degenerative Disc Disease: Current and Future Concepts of Diagnosis and Management

Low back pain as a result of degenerative disc disease imparts a large socioeconomic impact on the health care system. Traditional concepts for treatment of lumbar disc degeneration have aimed at symptomatic relief by limiting motion in the lumbar spine, but novel treatment strategies involving stem cells, growth factors, and gene therapy have the theoretical potential to prevent, slow, or even reverse disc degeneration. Understanding the pathophysiological basis of disc degeneration is essential for the development of treatment strategies that target the underlying mechanisms of disc degeneration rather than the downstream symptom of pain. Such strategies ideally aim to induce disc regeneration or to replace the degenerated disc. However, at present, treatment options for degenerative disc disease remain suboptimal, and development and outcomes of novel treatment options currently have to be considered unpredictable

Surveying Pseudomoduli: the Good, the Bad and the Incalculable

We classify possible types of pseudomoduli which arise when supersymmetry is dynamically broken in infrared-free low-energy theories. We show that, even if the pseudomoduli potential is generated only at higher loops, there is a regime where the potential can be simply determined from a combination of one-loop running data. In this regime, we compute whether the potential for the various types of pseudomoduli is safe, has a dangerous runaway to the UV cutoff of the low-energy theory, or is incalculable. Our results are applicable to building new models of supersymmetry breaking. We apply the results to survey large classes of models.Comment: 34 page

Molecular Physics

Contains reports on two research projects.F.L. Freidman ChairNational Institutes of Health (Grant AM 25535)Whitaker FoundationInternational Business Machines, Inc

Molecule Microscopy

Contains research objectives and reports on four research projects.National Institutes of Health (Grant AM-25535)Whitaker FoundationFrancis L. Friedman Chai