Measurement of np->npπ0π0 reaction in search for the recently observed d*(2380) resonance

Exclusive measurements of the quasi-free np →npπ0π0reaction have been performed by means of dpcollisions at Td=2.27GeVusing the WASA detector setup at COSY. Total and differential cross sections have been obtained covering the energy region √s=(2.35–2.46)GeV, which includes the region of the ABC effect and its associated d∗(2380)resonance. Adding the d∗resonance amplitude to that for the conventional processes leads to a reasonable description of the data. The observed resonance effect in the total cross section is in agreement with the predictions of Fäldt and Wilkin as well with those of Albadajedo and Oset. The ABC effect, i.e.the low-mass enhancement in the π0π0-invariant mass spectrum, is found to be very modest – if present at all, which might pose a problem to some of its interpretations

Micromechanical High-doses Radiation Sensor with Bossed Membrane and Interferometry Optical Read-out

AbstractThe silicon-glass MEMS high-doses radiation sensor with in situ detection, so far not possible in the field of detection of doses above 10 kGy, has been presented. The sensor consists of a chamber filled with the high density polyethylene (HDPE) and a silicon bossed membrane. The radiolysis product of HDPE increases the pressure inside the chamber causing the deflection of the membrane, which is proportional to the pressure, thus to radiation dose. The sensor has been irradiated with high energy electron beam and shows good detectability for 10-40 kGy. The deflection of the membrane has been detected by optical interferometer

Novel ageing-biomarker discovery using data-intensive technologies

Ageing is accompanied by many visible characteristics. Other biological and physiological markers are also well-described e.g. loss of circulating sex hormones and increased inflammatory cytokines. Biomarkers for healthy ageing studies are presently predicated on existing knowledge of ageing traits. The increasing availability of data-intensive methods enables deep-analysis of biological samples for novel biomarkers. We have adopted two discrete approaches in MARK-AGE Work Package 7 for biomarker discovery; (1) microarray analyses and/or proteomics in cell systems e.g. endothelial progenitor cells or T cell ageing including a stress model; and (2) investigation of cellular material and plasma directly from tightly-defined proband subsets of different ages using proteomic, transcriptomic and miR array. The first approach provided longitudinal insight into endothelial progenitor and T cell ageing.This review describes the strategy and use of hypothesis-free, data-intensive approaches to explore cellular proteins, miR, mRNA and plasma proteins as healthy ageing biomarkers, using ageing models and directly within samples from adults of different ages. It considers the challenges associated with integrating multiple models and pilot studies as rational biomarkers for a large cohort study. From this approach, a number of high-throughput methods were developed to evaluate novel, putative biomarkers of ageing in the MARK-AGE cohort

Supertransferred hyperfine interactions in layer LaSrGa0.995Cu0.005O4

The EPR allowing a direct observation of supertransferred hyperfine fields on the nuclei of the next-nearest cations to copper ion in the structure of LaSrGa0.995Cu0.005O4 isomorphous to the superconducting cuprates prove the far delocalisation of the spin density. The theoretical analysis of the value and mechanisms of this process by the method of configurational interaction leads to a good agreement with the experiment. It is shown that the cascade processes involving simultaneous electron transfers from the oxygen to the copper atom and from the neighbouring cation to the same oxygen, in the fragment considered bring a substantial contribution into polarisation of 3s-shell of gallium ion. A comparison of the supertransferred hyperfine fields and g-tensor values in the studied, diluted LaSrGa0.995Cu0.005O4 crystal and in the La2CuO4 cuprate confirms the validity of the local centre approach in the analysis of cuprate properties. © 2002 Elsevier Science B.V. All rights reserved

Examination of the production of an isotensor dibaryon in the pp → ppπ+π− reaction

Exclusive measurements of the quasi-free $pp o pppi^+pi^-$ reaction have been performed by means of $pd$ collisions at $T_p$ = 1.2 GeV using the WASA detector setup at COSY. Total and differential cross sections have been obtained covering the energy region $T_p = 1.08 - 1.36$ GeV ($sqrt s$ = 2.35 - 2.46 GeV), which includes the regions of $N^*(1440)$ and $Delta(1232)Delta(1232)$ resonance excitations. Calculations describing these excitations by $t$-channel meson exchange are at variance with experimental differential cross sections and underpredict substantially the measured total cross section. An isotensor $Delta N$ dibaryon resonance with $I(J^P) = 2(1^+)$ produced associatedly with a pion is able to overcome these deficiencies. Such a dibaryon was predicted by Dyson and Xuong and more recently calculated by Gal and Garcilazo

Spin tune mapping as a novel tool to probe the spin dynamics in storage rings

Precision experiments, such as the search for electric dipole moments of charged particles using storage rings, demand for an understanding of the spin dynamics with unprecedented accuracy. The ultimate aim is to measure the electric dipole moments with a sensitivity up to 15 orders in magnitude better than the magnetic dipole moment of the stored particles. This formidable task requires an understanding of the background to the signal of the electric dipole from rotations of the spins in the spurious magnetic fields of a storage ring. One of the observables, especially sensitive to the imperfection magnetic fields in the ring is the angular orientation of stable spin axis. Up to now, the stable spin axis has never been determined experimentally, and in addition, the JEDI collaboration for the first time succeeded to quantify the background signals that stem from false rotations of the magnetic dipole moments in the horizontal and longitudinal imperfection magnetic fields of the storage ring. To this end, we developed a new method based on the spin tune response of a machine to artificially applied longitudinal magnetic fields. This novel technique, called \textit{spin tune mapping}, emerges as a very powerful tool to probe the spin dynamics in storage rings. The technique was experimentally tested in 2014 at the cooler synchrotron COSY, and for the first time, the angular orientation of the stable spin axis at two different locations in the ring has been determined to an unprecedented accuracy of better than $2.8\mu$rad.Comment: 32 pages, 15 figures, 7 table

Phase Measurement for Driven Spin Oscillations in a Storage Ring

This paper reports the first simultaneous measurement of the horizontal and vertical components of the polarization vector in a storage ring under the influence of a radio frequency (rf) solenoid. The experiments were performed at the Cooler Synchrotron COSY in J\"ulich using a vector polarized, bunched $0.97\,\textrm{GeV/c}$ deuteron beam. Using the new spin feedback system, we set the initial phase difference between the solenoid field and the precession of the polarization vector to a predefined value. The feedback system was then switched off, allowing the phase difference to change over time, and the solenoid was switched on to rotate the polarization vector. We observed an oscillation of the vertical polarization component and the phase difference. The oscillations can be described using an analytical model. The results of this experiment also apply to other rf devices with horizontal magnetic fields, such as Wien filters. The precise manipulation of particle spins in storage rings is a prerequisite for measuring the electric dipole moment (EDM) of charged particles

Measurement of the ω→π+π−π0 Dalitz plot distribution

Using the production reactions and , the Dalitz plot distribution for the decay is studied with the WASA detector at COSY, based on a combined data sample of events. The Dalitz plot density is parametrised by a product of the P-wave phase space and a polynomial expansion in the normalised polar Dalitz plot variables Z and ϕ. For the first time, a deviation from pure P-wave phase space is observed with a significance of 4.1σ. The deviation is parametrised by a linear term , with α determined to be, consistent with the expectations of ρ-meson-type final-state interactions of the P-wave pion pairs

Search for the eta-mesic 4He with WASA-at-COSY detector

An exclusive measurement of the excitation function for the dd->3Heppi- reaction was performed at the Cooler Synchrotron COSY-Juelich with the WASA-at-COSY detection system. The data were taken during a slow acceleration of the beam from 2.185 GeV/c to 2.400 GeV/c crossing the kinematic threshold for the eta meson production in the dd->4He-eta reaction at 2.336 GeV/c. The corresponding excess energy with respect to the 4He-eta system varied from -51.4MeV to 22MeV. The integrated luminosity in the experiment was determined using the dd->3Hen reaction. The shape of the excitation function for the dd->3Heppi- was examined. No signal of the 4He-eta bound state was observed. An upper limit for the cross-section for the bound state formation and decay in the process dd->(4He-eta)bound->3Heppi- was determined on the 90% confidence level and it varies from 20nb to 27nb for the bound state width ranging from 5MeV to 35MeV, respectively.Comment: 8 pages, 9 figure