Search for dark photons as candidates for Dark Matter with FUNK

An additional U(1) symmetry predicted in theories beyond the Standard Model of particle physics can give rise to hidden (dark) photons. Depending on the mass and density of these hidden photons, they could account for a large fraction of the Dark Matter observed in the Universe. When passing through an interface of materials with different dielectric properties, hidden photons are expected to produce a tiny flux of photons. The wavelength of these photons is directly related to the mass of the hidden photons. In this contribution we report on measurements covering the visible and near-UV spectrum, corresponding to a dark photon mass in the eV range. The data were taken with the FUNK experiment using a spherical mirror of ~14m2 total area built up of 36 aluminum segments

Role of Sterile Neutrino Warm Dark Matter in Rhenium and Tritium Beta Decays

Sterile neutrinos with mass in the range of one to a few keV are important as extensions of the Standard Model of particle physics and are serious dark matter (DM) candidates. This DM mass scale (warm DM) is in agreement with both cosmological and galactic observations. We study the role of a keV sterile neutrino through its mixing with a light active neutrino in Rhenium 187 and Tritium beta decays. We pinpoint the energy spectrum of the beta particle, 0 < T_e < (Q_{beta} - m_s), as the region where a sterile neutrino could be detected and where its mass m_s could be measured. This energy region is at least 1 keV away rom the region suitable to measure the mass of the light active neutrino, located near the endpoint Q_{beta} . The emission of a keV sterile neutrino in a beta decay could show up as a small kink in the spectrum of the emitted beta particle. With this in view, we perform a careful calculation of the Rhenium and Tritium beta spectra and estimate the size of this perturbation by means of the dimensionless ratio R of the sterile neutrino to the active neutrino contributions. We comment on the possibility of searching for sterile neutrino signatures in two experiments which are currently running at present, MARE and KATRIN, focused on the Rhenium 187 and Tritium beta decays respectively.Comment: 16 pages, 10 figures. Version to appear in Nucl. Phys. B. Results and conclusions unchange

A mathematical framework for critical transitions: normal forms, variance and applications

Critical transitions occur in a wide variety of applications including mathematical biology, climate change, human physiology and economics. Therefore it is highly desirable to find early-warning signs. We show that it is possible to classify critical transitions by using bifurcation theory and normal forms in the singular limit. Based on this elementary classification, we analyze stochastic fluctuations and calculate scaling laws of the variance of stochastic sample paths near critical transitions for fast subsystem bifurcations up to codimension two. The theory is applied to several models: the Stommel-Cessi box model for the thermohaline circulation from geoscience, an epidemic-spreading model on an adaptive network, an activator-inhibitor switch from systems biology, a predator-prey system from ecology and to the Euler buckling problem from classical mechanics. For the Stommel-Cessi model we compare different detrending techniques to calculate early-warning signs. In the epidemics model we show that link densities could be better variables for prediction than population densities. The activator-inhibitor switch demonstrates effects in three time-scale systems and points out that excitable cells and molecular units have information for subthreshold prediction. In the predator-prey model explosive population growth near a codimension two bifurcation is investigated and we show that early-warnings from normal forms can be misleading in this context. In the biomechanical model we demonstrate that early-warning signs for buckling depend crucially on the control strategy near the instability which illustrates the effect of multiplicative noise.Comment: minor corrections to previous versio

Ro 04-6790-induced cognitive enhancement: No effect in trace conditioning and novel object recognition procedures in adult male Wistar rats

The evidence for cognitively enhancing effects of 5-hydroxytryptamine6 (5-HT6) receptor antagonists such as Ro 04-6790 is inconsistent and seems to depend on the behavioural test variant in use. Trace conditioning holds promise as a behavioral assay for hippocampus-dependent working memory function. Accordingly, Experiment 1 assessed the effect of Ro 04-6790 (5 and 10 mg/kg i.p.) on associating a noise conditioned stimulus paired with foot shock (unconditioned stimulus) at a 3 or 30 s trace interval in adult male Wistar rats. Contextual conditioning was measured as suppression to the contextual cues provided by the experimental chambers and as suppression to a temporally extended light background stimulus which provided an experimental context. Experiment 2 assessed the effect of Ro 04-6790 (5 and 10 mg/kg i.p.) on recognition memory as tested by the exploration of novel relative to familiar objects in an open arena. In Experiment 1, Ro 04-6790 (5 and 10 mg/kg) was without effect on trace and contextual conditioning. In Experiment 2, there was no indication of the expected improvement under Ro 04-6790 at the same doses previously found to enhance recognition memory as measured in tests of novel object exploration. Thus, there was no evidence that treatment with the 5-HT6 receptor antagonist Ro 04-6790 acted as a cognitive enhancer in either trace conditioning or object recognition procedures. We cannot exclude the possibility that the experimental procedures used in the present study would have been sensitive to the cognitive enhancing effects of Ro 04-6790 in a different dose range, behavioral test variant, or in a different strain of rat. Nonetheless the drug treatment was not ineffective in that object exploration was reduced under 10 mg/kg Ro 04-6790

Hierarchically Acting Sterile Neutrinos

We propose that a hierarchical spectrum of sterile neutrinos (eV, keV, $10^{13-15}$ GeV) is considered to as the explanations for MiniBooNE and LSND oscillation anomalies, dark matter, and baryon asymmetry of the universe (BAU) respectively. The scenario can also realize the smallness of active neutrino masses by seesaw mechanism.Comment: 4 pages, 1 tabl

Updated precision measurement of the average lifetime of B hadrons

The measurement of the average lifetime of B hadrons using inclusively reconstructed secondary vertices has been updated using both an improved processing of previous data and additional statistics from new data. This has reduced the statistical and systematic uncertainties and gives \tau_{\mathrm{B}} = 1.582 \pm 0.011\ \mathrm{(stat.)} \pm 0.027\ \mathrm{(syst.)}\ \mathrm{ps.} Combining this result with the previous result based on charged particle impact parameter distributions yields \tau_{\mathrm{B}} = 1.575 \pm 0.010\ \mathrm{(stat.)} \pm 0.026\ \mathrm{(syst.)}\ \mathrm{ps.

Limits on the production of scalar leptoquarks from Z (0) decays at LEP

A search has been made for pairs and for single production of scalar leptoquarks of the first and second generations using a data sample of 392000 Z0 decays from the DELPHI detector at LEP 1. No signal was found and limits on the leptoquark mass, production cross section and branching ratio were set. A mass limit at 95% confidence level of 45.5 GeV/c2 was obtained for leptoquark pair production. The search for the production of a single leptoquark probed the mass region above this limit and its results exclude first and second generation leptoquarks D0 with masses below 65 GeV/c2 and 73 GeV/c2 respectively, at 95% confidence level, assuming that the D0lq Yukawa coupling alpha(lambda) is equal to the electromagnetic one. An upper limit is also given on the coupling alpha(lambda) as a function of the leptoquark mass m(D0)

Prompt K_short production in pp collisions at sqrt(s)=0.9 TeV

The production of K_short mesons in pp collisions at a centre-of-mass energy of 0.9 TeV is studied with the LHCb detector at the Large Hadron Collider. The luminosity of the analysed sample is determined using a novel technique, involving measurements of the beam currents, sizes and positions, and is found to be 6.8 +/- 1.0 microbarn^-1. The differential prompt K_short production cross-section is measured as a function of the K_short transverse momentum and rapidity in the region 0 < pT < 1.6 GeV/c and 2.5 < y < 4.0. The data are found to be in reasonable agreement with previous measurements and generator expectations.Comment: 6+18 pages, 6 figures, updated author lis

Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362