First πK\pi K atom lifetime and πK\pi K scattering length measurements

The results of a search for hydrogen-like atoms consisting of $\pi^{\mp}K^{\pm}$ mesons are presented. Evidence for $\pi K$ atom production by 24 GeV/c protons from CERN PS interacting with a nickel target has been seen in terms of characteristic $\pi K$ pairs from their breakup in the same target ($178 \pm 49$) and from Coulomb final state interaction ($653 \pm 42$). Using these results the analysis yields a first value for the $\pi K$ atom lifetime of $\tau=(2.5_{-1.8}^{+3.0})$ fs and a first model-independent measurement of the S-wave isospin-odd $\pi K$ scattering length $\left|a_0^-\right|=\frac{1}{3}\left|a_{1/2}-a_{3/2}\right|= \left(0.11_{-0.04}^{+0.09} \right)M_{\pi}^{-1}$ ($a_I$ for isospin $I$).Comment: 14 pages, 8 figure

Determination of ππ\pi\pi scattering lengths from measurement of π+π−\pi^+\pi^- atom lifetime

The DIRAC experiment at CERN has achieved a sizeable production of $\pi^+\pi^-$ atoms and has significantly improved the precision on its lifetime determination. From a sample of 21227 atomic pairs, a 4% measurement of the S-wave $\pi\pi$ scattering length difference $|a_0-a_2| = (.0.2533^{+0.0080}_{-0.0078}|_\mathrm{stat}.{}^{+0.0078}_{-0.0073}|_\mathrm{syst})M_{\pi^+}^{-1}$ has been attained, providing an important test of Chiral Perturbation Theory.Comment: 6 pages, 6 figure

Potential reduction in nutrient leachability from sewage sludge applied in land reclamation

Referat dotyczy uwalniania składników organicznych i węgla organicznego z osadu ściekowego stosowanego w rekultywacji zgodnie z rekomendacjami BREF/IPPC dla odpadów i skał płonnych. Zawartości Ncałk i Pcałk w szlamie przekraczają standardy zanieczyszczenia powierzchni wody na co wskazuje rozporządzenie Rządu 229/2007. Dodanie 10% kaolinitu i bentonitu znacząco zmniejsza zdolność do wymywania Ptotal; osiągnięto wskaźnik adsorpcji dla kaolinitu i bentonitu kolejno 83% i 88%. Podczas jednotygodniowej stabilizacji osadu nastąpił istotny rozpad związków organicznych, którego rezultatem był wzrost zawartości Ncałk oraz nierozpuszczonego węgla organicznego w odcieku. Stężenie Ncałk w odcieku wzrosło o połowę, w nierozpuszczonym węglu organicznym (DOC) zwiększyło się o 2/3. W przypadku wyższych stężeń Ncałk i DOC w odcieku, wydajność adsorpcji kaolinitu i bentonitu jest wyższa. Efekt dodatku podstawowych minerałów gliny nie objawił się w formie zmniejszonej toksyczności osadu.The paper deals with the release of nutrients and organic carbon from sewage sludge applied in land reclamation within BREF/ IPPC recommendations for tailings and waste rock management. The contents of Ntotal and Ptotal in the sludge leachate exceed the pollution standards of permissible surface water pollution according to Government Decree 229/2007 Coll. Adding 10% of kaolinite and bentonite significantly decreases the leachability of Ptotal; the adsorption efficiency reached 83% in kaolinite and 88% in bentonite. During oneweek stabilization of sludge there was a substantial decomposition of organic compounds, which resulted in a rise in the contents of Ntotal and dissolved organic carbon in the leachate. The content of Ntotal in the leachate increased by a half, in the dissolved organic carbon (DOC) it rose by 2/3. At higher concentrations of Ntotal and DOC in the leachate the efficiency of adsorption of kaolinite and bentonite is higher. The effect of additives on the base of clay minerals did not manifest in the form of reduced ecotoxicity of the sludge leachate

Ecotoxicity of sewage sludge from waste water treatment plant

Tematem artykułu jest określenie przyczyn toksyczności ścieków. Toksyczność badano na rozwielitkach Daphnia magna oraz algach Desmodesmus subspicatus. Dla zmniejszenia toksyczności, do wartości określonej przez ustawę nr 294/2005 Coll., do ekstraktu wodnego dodano różne sorbenty (aktywny węgiel i amberlit - XAD - niejonowy absorbent polimerowy). Ustalono, że mętność wody spowodowana dodaniem aktywnego węgla wpływa na zachowanie Desmodesmus subspicatus. Koncentracja składników odżywczych uwolnionych ze ścieków oraz przez obecność zanieczyszczeń (PAH, AOX i metale ciężkie) także wpływa na zachowanie alg. Dodatek aktywnego węgla zmniejszył koncentrację PAH poniżej limitu, co jest niebezpieczne dla Daphnia magna, ale zmniejszenie zawartości składników szkodliwych w wodzie nie było wystarczające. Nie osiągnięto granicznych wartości EC50 dla Pb, Zn i Cu określonych w literaturze.Article is oriented on the cause of sludge ecotoxicity. The ecotoxicity was studied on Daphnia magna and algae Desmodesmus subspicatus. For decreasing of water extract exotoxicity to the limit value required by Decree No.294/2005 Coll. the addition of different sorbent (active carbon and Amberlite – XAD nonionic polymeric absorbent) were observed. The behaviour of Desmodesmus subspicatus is influenced by turbidity of water extract after adding of aktive carbon, concentration of nutrients releasing from sludge and also by presence of pollutants (PAHs, AOXs and heavy metals). The addion of activated carbon decrease the concentration of PAHs below the limit which is hazardous for Daphnia magna, but the decreasing of hazardous elements in water extract was not sufficient. The limit value EC50 published in literature for Pb, Zn and Cu was not reached

First measurement of a long-lived π+π−\pi^+ \pi^- atom lifetime

The adapted DIRAC experiment at the CERN PS accelerator observed for the first time long-lived hydrogen-like $\pi^+\pi^-$ atoms, produced by protons hitting a beryllium target. A part of these atoms crossed the gap of 96~mm and got broken up in the 2.1~\textmu{}m thick platinum foil. Analysing the observed number of atomic pairs, $n_A^L= \left.436^{+157}_{-61}\right|_\mathrm{tot}$, the lifetime of the 2$p$ state is found to be ${\tau_{2p}=(\left.0.45^{+1.08}_{-0.30}\right|_\mathrm{tot}) \cdot10^{-11}}$s, not contradicting the corresponding QED $2p$ state lifetime ${\tau_{2p}^\mathrm{QED}=1.17 \cdot 10^{-11}}$s. This lifetime value is three orders of magnitude larger than our previously measured value of the $\pi^+\pi^-$ atom ground state lifetime $\tau=(\left.3.15^{+0.28}_{-0.26}\right|_\mathrm{tot})\cdot 10^{-15}$s. Further studies of long-lived $\pi^+\pi^-$ atoms will allow to measure energy differences between $p$ and $s$ atomic states and so to determine $\pi\pi$ scattering lengths with the aim to check QCD predictions.The adapted DIRAC experiment at the CERN PS accelerator observed for the first time long-lived hydrogenlike π+π- atoms, produced by protons hitting a beryllium target. A part of these atoms crossed the gap of 96 mm between the target and a 2.1  μm thick platinum foil, in which most of them dissociated. Analyzing the observed number of atomic pairs, nAL=436-61+157|tot, the lifetime of the 2p state is found to be τ2p=(0.45-0.30+1.08|tot)×10-11  s, not contradicting the corresponding QED 2p state lifetime τ2pQED=1.17×10-11  s. This lifetime value is three orders of magnitude larger than our previously measured value of the π+π- atom ground state lifetime τ=(3.15-0.26+0.28|tot)×10-15  s. Further studies of long-lived π+π- atoms will allow us to measure energy differences between p and s atomic states and so to discriminate between the isoscalar and isotensor ππ scattering lengths with the aim to check QCD predictions.The adapted DIRAC experiment at the CERN PS accelerator observed for the first time long-lived hydrogen-like $\pi^+\pi^-$ atoms, produced by protons hitting a beryllium target. A part of these atoms crossed the gap of 96~mm and got broken up in the 2.1~\textmu{}m thick platinum foil. Analysing the observed number of atomic pairs, $n_A^L= \left.436^{+157}_{-61}\right|_\mathrm{tot}$, the lifetime of the 2$p$ state is found to be ${\tau_{2p}=(\left.0.45^{+1.08}_{-0.30}\right|_\mathrm{tot}) \cdot10^{-11}}$s, not contradicting the corresponding QED $2p$ state lifetime ${\tau_{2p}^\mathrm{QED}=1.17 \cdot 10^{-11}}$s. This lifetime value is three orders of magnitude larger than our previously measured value of the $\pi^+\pi^-$ atom ground state lifetime $\tau=(\left.3.15^{+0.28}_{-0.26}\right|_\mathrm{tot})\cdot 10^{-15}$s. Further studies of long-lived $\pi^+\pi^-$ atoms will allow to measure energy differences between $p$ and $s$ atomic states and so to determine $\pi\pi$ scattering lengths with the aim to check QCD predictions

First observation of long-lived π+π− atoms

After observing and investigating the double-exotic (a double-exotic atom is a bound system, in which both oppositely charged components are unstable particles like μ,π,K,…) π+π− atom with the ground state lifetime τ of about 3×10−15 s, the upgraded DIRAC experiment at the CERN PS accelerator observes for the first time long-lived states of the same atom with lifetimes of about 10−11 s and more. The number of characteristic pion pairs resulting from the breakup (ionisation) of long-lived π+π− atoms amounts to 436±61, corresponding to a signal-to-error ratio of better than 7 standard deviations. This observation opens a new possibility to measure energy differences between p and s atomic states and so to determine ππ scattering lengths

Observation of π−K+\pi^- K^+ and π+K−\pi^+ K^- atoms

The observation of hydrogen-like $\pi K$ atoms, consisting of $\pi^- K^+$ or $\pi^+ K^-$ mesons, is presented. The atoms have been produced by 24 GeV/$c$ protons from the CERN PS accelerator, interacting with platinum or nickel foil targets. The breakup (ionisation) of $\pi K$ atoms in the same targets yields characteristic $\pi K$ pairs, called ``atomic pairs'', with small relative momenta in the pair centre-of-mass system. The upgraded DIRAC experiment has observed $349\pm62$ such atomic $\pi K$ pairs, corresponding to a signal of 5.6 standard deviations

Updated DIRAC spectrometer at CERN PS for the investigation of ππ and πK atoms

The DIRAC spectrometer installed at CERN PS was redesigned and upgraded in order to study simultaneously Aππ and AπK atoms, namely the bound states of π+π–, and π+K–, π–K+ mesons. The detector system which is able to accept a high intensity beam such as 2 - 6 × 1011 primary protons per second, the electronics and the data-acquisition system adapted to handle very large amount of data actually allowed to identify successfully π, K, p, e and µ and to give the possibility to select π-π and π-K pairs in the off-line analysis. The setup’s capability of giving a high resolution in the reconstruction of the relative momentum in the pair-CMS Q gave the possibility to analyze the distributions of its components, in order to identify the signal from pairs originating from hadronic atoms, and to measure their lifetimes in the ground state and π-π and π-K s-wave scattering lengths. The setup also allowed to study long-lived excited states of π-π atoms