A new event display for the KLOE-2 experiment

In this contribution, we describe KNEDLE — the new event display for the KLOE-2 experiment. The basic objectives and software requirements are presented. The current status of the development is given along with a short discussion of the future plans

Studies of mesic nuclei via decay reactions

Collisions in a system of two particles at energies close to a bound state in different channels are discussed. Next, the bound state decays into a third coupled channel. A phenomenological approach to $dd \rightarrow \pi^{-}p^{3}He$ reaction is presented

Poszukiwanie stanów związanych 4He−η^{4}He-\eta na detektorze WASA-at-COSY

We performed a search for the 4 He - η bound state via exclusive measurement of the excitation function for the dd → 3 Hepπ - reaction, where the outgoing p - π - pair originates from the conversion of the η meson on a neutron inside the 4 He nucleus. The measurements were performed at the Cooler Synchrotron COSY-Juelich with the WASA-at-COSY detection system. The internal deuteron beam of COSY was scattered on a pellet-type deuteron target. The data were taken during a slow acceleration of the beam from 2.185 GeV/c to 2.400 GeV/c crossing the kinematical threshold for the η production in the dd → 4 He η reaction at 2.336 GeV/c. The corresponding excess energy in the 4 He-η system varied from -51.4 MeV to 22 MeV. Events corresponding to decays of the η-mesic 4 He were selected using cuts on the 3 He momentum, p and π - kinetic energies and the relative p - π - angle in the center of mass system. The range of the applied cuts was inferred from simulations of decay of the 4 He - η bound state proceeding via excitation the N ∗ resonance. The integrated luminosity in the experiment was determined using the dd → 3 Hen reaction and the relative normalization of the points of the dd → 3 Hepπ - excitation function was based on the quasi-elastic proton-proton scattering. No signal of the 4 He - η bound state was observed in the excitation function. An upper limit for the cross-section for the bound state formation and decay in the process dd → (4 He - η)bound → 3 Hepπ - , determined for the bound state width of 10, 20 and 30 MeV equals to 28, 32 and 41 nb, respectively. The measured angular and momentum distributions of the reaction products are close to those simulated under the assumption of uniform phase-space distribution

Development of the normalization method for the Jagiellonian PET scanner

This work aims at applying the theory of the component-based normalization to the Jagiellonian PET scanner, currently under development at the Jagiellonian University. In any positron emission tomography acquisition, efficiency along a line-of-response can vary due to several physical and geometrical effects, leading to severe artifacts in the reconstructed image. To mitigate these effects, a normalization coefficient is applied to each line-of-response, defined as the product of several components. The specificity of the Jagiellonian PET scanner geometry is taken into account. The results obtained from the GATE simulations are compared with the preliminary results obtained from the experimental data

Mirror matter searches with the J-PET detector

The positronium system — a bound state of an electron and a positron — is suitable for testing the predictions of quantum electrodynamics, since its properties can be perturbatively calculated to high accuracy and, unlike the hydrogen system, it is not affected by the finite size or quantum chromodynamics effects at the current level of experimental precision. Experiments searching for invisible decays of the positronium triplet state — the ortho-positronium — which mainly decays to three photons, are being conducted since they are sensitive to new physics scenarios, e.g., mirror matter, milli-charged particles, and extra space-time dimensions. The particular case of mirror matter and its search with the novel total-body positron emission tomography scanner at the Jagiellonian University is presented. This J-PET is a large, high precision medical imaging tool based on plastic scintillators

Ionization spectroscopy in cold rubidium atoms

We demonstrate photoionization spectroscopy in cold rubidium atoms trapped in a working magneto-optical trap. Three-photon ionization with two-photon resonance proceeds along various channels, with the step-by-step 5S-5P-5D transition and with the two-photon excitation of the 5D or 7S state. The processes are monitored by measuring ion signals which allow sensitive spectroscopy of weak transitions in a cold-atom sample

Litter selfie : a citizen science guide for photorecording macroplastic deposition along mountain rivers using a smartphone

Macroplastic pollution in mountain rivers can threaten water resources, biodiversity, and the recreational values provided by them. The first step towards evaluating and then mitigating these risks is the systematic collection of reliable and spatially uniform data on the amount and type of macroplastics deposited in different land covers occurring in a mountain river channel. To maximise the opportunity for the large-scale collection of such data using the citizen science approach, we propose in this study an illustrated step-by-step guide to sample the macroplastic deposited along mountain rivers and to record the collected information using a photo taken by smartphone and a simple online form. Our guide includes three steps: (i) the location of sampling plots across 3-4 predefined surface covers occurring in mountain rivers of temperate climate, (ii) the hand collection of macroplastic deposited in them, and (iii) the photorecording and archiving of information on macroplastics collected using a smartphone and an online form. The proposed guide can allow for the low-cost collection of data on macroplastic deposition in mountain rivers on regional and global scales. The collected data can be further analysed by environmental scientists to quantify the amount and types of macroplastic deposited and to evaluate the resulting risks. They can be also used as illustrative materials to increase the awareness of local communities about the plastic pollution problem

Studies of discrete symmetries in decays of positronium atoms

A positronium - a bound state of electron and positron - is an eigenstate of parity and charge conjugation operators which decays into photons. It is a unique laboratory to study discrete symmetries whose precision is limited, in principle, by the effects due to the weak interactions expected at the level of 10−14 and photon-photon interactions expected at the level of 10−9. The Jagiellonian Positron Emission Tomograph (J-PET) is a detector for medical imaging as well as for physics studies involving detection of electronpositron annihilation into photons. The physics case covers the areas of discrete symmetries studies and genuine multipartite entanglement. The J-PET detector has high angular and time resolution and allows for determination of spin of the positronium and the momenta and polarization vectors of annihilation quanta. In this article, we present the potential of the J-PET system for studies of discrete symmetries in decays of positronium atoms

3D PET image reconstruction based on Maximum Likelihood Estimation Method (MLEM) algorithm

Positron emission tomographs (PET) do not measure an image directly. Instead, they measure at the boundary of the field-of-view (FOV) of PET tomograph a sinogram that consists of measurements of the sums of all the counts along the lines connecting two detectors. As there is a multitude of detectors build-in typical PET tomograph structure, there are many possible detector pairs that pertain to the measurement. The problem is how to turn this measurement into an image (this is called imaging). Decisive improvement in PET image quality was reached with the introduction of iterative reconstruction techniques. This stage was reached already twenty years ago (with the advent of new powerful computing processors). However, three dimensional (3D) imaging remains still a challenge. The purpose of the image reconstruction algorithm is to process this imperfect count data for a large number (many millions) of lines-of-responce (LOR) and millions of detected photons to produce an image showing the distribution of the labeled molecules in space.Comment: 10 pages, 7 figure

Optimal geometry for efficient loading of an optical dipole trap

One important factor which determines efficiency of loading cold atoms into an optical dipole trap from a magneto-optical trap is the distance between the trap centers. By studying this efficiency for various optical trap depths (2--110 mK) we find that for optimum dipole trap loading, longitudinal displacements up to 15 mm are necessary. An explanation for this observation is presented and compared with other work and a simple analytical formula is derived for the optimum distance between the trap centers.Comment: 6 figures. Phys. Rev. A, in pres