The K¯N system at threshold is a sensitive testing ground for low energy QCD, especially for the explicit chiral symmetry breaking. Therefore, we have measured the K-series X-rays of kaonic hydrogen ...atoms at the DAΦNE electron–positron collider of Laboratori Nazionali di Frascati, and have determined the most precise values of the strong-interaction energy-level shift and width of the 1s atomic state. As X-ray detectors, we used large-area silicon drift detectors having excellent energy and timing resolution, which were developed especially for the SIDDHARTA experiment. The shift and width were determined to be ϵ1s=−283±36(stat)±6(syst) eV and Γ1s=541±89(stat)±22(syst) eV, respectively. The new values will provide vital constraints on the theoretical description of the low-energy K¯N interaction.
The first observation of the kaonic 3He 3d→2p transition was made, using slow K− mesons stopped in a gaseous 3He target. The kaonic atom X-rays were detected with large-area silicon drift detectors ...using the timing information of the K+K− pairs of ϕ-meson decays produced by the DAΦNE e+e− collider. The strong interaction shift of the kaonic 3He 2p state was determined to be −2±2(stat)±4(syst) eV.
The study of the K¯N system at very low energies plays a key role for the understanding of the strong interaction between hadrons in the strangeness sector. At the DAΦNE electron–positron collider of ...Laboratori Nazionali di Frascati we studied kaonic atoms with Z=1 and Z=2, taking advantage of the low-energy charged kaons from Φ-mesons decaying nearly at rest. The SIDDHARTA experiment used X-ray spectroscopy of the kaonic atoms to determine the transition yields and the strong interaction induced shift and width of the lowest experimentally accessible level (1s for H and D and 2p for He). Shift and width are connected to the real and imaginary part of the scattering length. To disentangle the isospin dependent scattering lengths of the antikaon–nucleon interaction, measurements of K−p and of K−d are needed. We report here on an exploratory deuterium measurement, from which a limit for the yield of the K-series transitions was derived: Y(Ktot)<0.0143 and Y(Kα)<0.0039 (CL 90%). Also, the upcoming SIDDHARTA-2 kaonic deuterium experiment is introduced.
Chronic obstructive pulmonary disease (COPD) is a respiratory disease that results in airflow limitation and respiratory distress, also having many nonrespiratory manifestations that affect both ...function and mobility. Preliminary evidence suggests that balance deficits constitute an important secondary impairment in individuals with COPD. Our objective was to investigate balance performance in two groups of COPD patients with different body compositions and to observe which of these groups are more likely to experience falls in the future.
We included 27 stable COPD patients and 17 healthy individuals who performed a series of balance tests. The COPD patients were divided in two groups: emphysematous and bronchitic. Patients completed the activities balance confidence scale and the COPD assessment test questionnaire and afterward performed the Berg Balance Scale, timed up and go, single leg stance and 6-minute walking distance test. We analyzed the differences in the balance tests between the studied groups.
Bronchitic COPD was associated with a decreased value when compared to emphysematous COPD for the following variables: single leg stance (8.7 vs 15.6; P<0.001) and activities balance confidence (53.2 vs 74.2; P=0.001). Bronchitic COPD patients had a significantly higher value of timed up and go test compared to patients with emphysematous COPD (14.7 vs 12.8; P=0.001).
Patients with COPD have a higher balance impairment than their healthy peers. Moreover, we observed that the bronchitic COPD phenotype is more likely to experience falls compared to the emphysematous phenotype.
The kaonic (3)He and (4)He X-rays emitted in the Formula: see text transitions were measured in the SIDDHARTA experiment. The widths of the kaonic (3)He and (4)He 2p states were determined to be ...Formula: see text, and Formula: see text, respectively. Both results are consistent with the theoretical predictions. The width of kaonic (4)He is much smaller than the value of Formula: see text determined by the experiments performed in the 70's and 80's, while the width of kaonic (3)He was determined for the first time.
The impact of excess rainfall on the maximum flow rate in the upper and middle basin of Prahova River. The present paper analyzes the impact of excess rainfall on the maximum flow rate in the upper ...and middle basin of Prahova River. In the last centuries, the upper and middle basin of the Prahova River has been increasingly affected by floods, which have had importand social and economic consequences, for this reason, this study is focused on the impact of the excess rainfall over the maximum flow rate and also the spatial and temporal variability of it, centered in the 19932013 period. The monthly and annual maximum flow data series from Buşteni and Câmpina hydrometic stations were capitalized through statistical analyzes. Maximum flows were reported at the tresholds values according to DEFENCE LEVELS. The purpose of the paper is to highlight how the maximum flow varies during the analysed period, to mark the floods that have taken place in this area, their impact on society and the environmnet, and also methods to combat negative effects.
Large-area silicon drift detectors (SDDs) were used for the first time in the background condition of a collider for precision spectroscopy of the kaonic atom X-rays in the SIDDHARTA experiment for ...the study of the strong interaction in a low-energy regime. The measurements were performed at the
DA
Φ
NE
electron–positron collider (LNF, Italy), using gas targets of hydrogen, deuterium, helium-3, and helium-4. A test measurement using the kaonic
4He X-rays showed an excellent performance of the SDD devices under the beam conditions, and a good background suppression capability using the time correlation between the kaonic atom X-rays and the back-to-back correlated K
+K
− pairs produced by
φ
decays.
The X-ray transition yields of kaonic atoms produced in Kapton polyimide (C22H10N2O5) were measured for the first time in the SIDDHARTA experiment. X-ray yields of the kaonic atoms with low atomic ...numbers (Z=6,7, and 8) and transitions with high principal quantum numbers (n=5–8) were determined. The relative yields of the successive transitions in the same atoms and the yield ratios of carbon-to-nitrogen (C:N) and carbon-to-oxygen (C:O) for the same transitions were also determined. These X-ray yields provide important information for understanding the capture ratios and cascade mechanisms of kaonic atoms produced in a compound material, such as Kapton.
The kaonic 3He and 4He 3d→2p transitions in gaseous targets were observed by the SIDDHARTA experiment. The X-ray energies of these transitions were measured with large-area silicon-drift detectors ...using the timing information of the K+K− pairs produced by the DAΦNE e+e− collider. The strong-interaction shifts and widths both of the kaonic 3He and 4He 2p states were determined, which are much smaller than the results obtained by the previous experiments. The “kaonic helium puzzle” (a discrepancy between theory and experiment) was now resolved.
The kaonic 3He and 4He X-rays emitted in the 3d→2p transitions were measured in the SIDDHARTA experiment. The widths of the kaonic 3He and 4He 2p states were determined to be Γ2p(He3)=6±6(stat.)±7 ...(syst.) eV, and Γ2p(He4)=14±8 (stat.)±5 (syst.) eV, respectively. Both results are consistent with the theoretical predictions. The width of kaonic 4He is much smaller than the value of 55±34 eV determined by the experiments performed in the 70ʼs and 80ʼs, while the width of kaonic 3He was determined for the first time.
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