The KAMEO proposal: Investigation of the E2 nuclear resonance effects in kaonic atoms

- The E2 nuclear resonance effect is a phenomenon that occurs when the energy of an atomic de-excitation state closely matches that of a nuclear excita-tion state, resulting in the attenuation of certain atomic X-ray lines in the resonant isotope target. The study of this effect in kaonic atoms can provide important insight into the mechanisms of the strong kaon-nucleus interaction. In 1975, Goldfrey, Lum, and Wiegand at Lawrence Berkeley Laboratory observed the effect in 98 42Mo, but they did not have enough data to reach a conclusive result. The E2 nuclear resonance effect is expected to occur in four kaonic molybdenum isotopes (94 42Mo, 9642Mo, 98 42Mo, and 100 42 Mo) with similar energy values. The KAMEO (Kaonic Atoms Measuring Nuclear Resonance Effects Observables) proposal plans to study this effect in these isotopes at the DA & phi;NE & phi; factory during the SIDDHARTA-2 experiment. KAMEO will use four solid strip targets, each enriched with a different molybdenum isotope, and expose them to negatively charged kaons produced by & phi; meson decays. The X-ray transition measurements will be performed using a high-purity germanium detector, and an additional solid strip target of non-resonant 9242Mo isotope will be exposed and used as a reference for standard non-resonant transitions

KAONIC HELIUM-4 L-SERIES YIELD MEASUREMENT AT 2.25 g/l DENSITY BY SIDDHARTA-2 at DAΦNE

This article presents the results of the kaonic helium-4 measurement conducted by the SIDDHARTA-2 experiment, aiming to provide crucial insights into the low-energy strong interaction in the strangeness sector. High-precision X-ray spectroscopy is used to examine the interaction between negatively charged kaons and nuclei in atomic systems. The SIDDHARTA-2 setup was optimized through the kaonic helium-4 measurement in preparation for the challenging kaonic deuterium measurement. The kaonic helium-4 measurement at a new density of 2.25 g/l is reported, providing the absolute and relative yields for the L-series transitions, which are essential data for understanding kaonic atom cascade processes

Potentialities of CdZnTe Quasi-Hemispherical Detectors for Hard X-ray Spectroscopy of Kaonic Atoms at the DAΦNE Collider

Kaonic atom X-ray spectroscopy is a consolidated technique for investigations on the physics of strong kaon-nucleus/nucleon interaction. Several experiments have been conducted regarding the measurement of soft X-ray emission (<20 keV) from light kaonic atoms (hydrogen, deuterium, and helium). Currently, there have been new research activities within the framework of the SIDDHARTA-2 experiment and EXCALIBUR proposal focusing on performing precise and accurate measurements of hard X-rays (>20 keV) from intermediate kaonic atoms (carbon, aluminum, and sulfur). In this context, we investigated cadmium-zinc-telluride (CdZnTe or CZT) detectors, which have recently demonstrated high-resolution capabilities for hard X-ray and gamma-ray detection. A demonstrator prototype based on a new cadmium-zinc-telluride quasi-hemispherical detector and custom digital pulse processing electronics was developed. The detector covered a detection area of 1 cm2 with a single readout channel and interesting room-temperature performance with energy resolution of 4.4% (2.6 keV), 3% (3.7 keV), and 1.4% (9.3 keV) FWHM at 59.5, 122.1, and 662 keV, respectively. The results from X-ray measurements at the DAΦNE collider at the INFN National Laboratories of Frascati (Italy) are also presented with particular attention to the effects and rejection of electromagnetic and hadronic background

New opportunities for kaonic atoms measurements from CdZnTe detectors

We present the tests performed by the SIDDHARTA-2 collaboration at the DA Φ NE collider with a quasi-hemispherical CdZnTe detector. The very good room-temperature energy resolution and efficiency in a wide energy range show that this detector technology is ideal for studying radiative transitions in intermediate and heavy mass kaonic atoms. The CdZnTe detector was installed for the first time in an accelerator environment to perform tests on the background rejection capabilities, which were achieved by exploiting the SIDDHARTA-2 Luminosity Monitor. A spectrum with an 241Am source has been acquired, with beams circulating in the main rings, and peak resolutions of 6% at 60 keV and of 2.2% at 511 keV have been achieved. The background suppression factor, which turned out to be of the order of ≃ 10 5 - 6 , opens the possibility to plan for future kaonic atom measurements with CdZnTe detectors

First measurement of kaonic helium-4 M-series transitions

In this paper we present the results of a new kaonic helium-4 measurement with a 1.37 g l−1 gaseous target by the SIDDHARTA-2 experiment at the DAΦNE collider. We measured, for the first time, the energies and yields of three transitions belonging to the M-series. Moreover, we improved by a factor about three, the statistical precision of the 2p level energy shift and width induced by the strong interaction, obtaining the most precise measurement for gaseous kaonic helium, and measured the yield of the Lα transition at the employed density, providing a new experimental input to investigate the density dependence of kaonic atoms transitions yield

First measurement of kaonic helium-4 M-series transitions

In this paper we present the results of a new kaonic helium-4 measurement with a 1.37 g/l gaseous target by the SIDDHARTA-2 experiment at the DA{\Phi}NE collider. We measured, for the first time, the energies and yields of three transitions belonging to the Mseries. Moreover, we improved by a factor about three, the statistical precision of the 2p level energy shift and width induced by the strong interaction, obtaining the most precise measurement for gaseous kaonic helium, and measured the yield of the L{\alpha} transition at the employed density, providing a new experimental input to investigate the density dependence of kaonic atoms transitions yield.Comment: 12 pages, 5 figures, 3 table

THE ODYSSEY OF KAONIC ATOMS STUDIES AT THE DAΦNE COLLIDER: FROM DEAR TO SIDDHARTA-2

In this paper, an overview of kaonic atoms studies from the late 90s to nowadays at the DAΦNE collider at INFN-LNF is presented. Experiments on kaonic atoms are an important tool to test and optimize phenomenological models on the low-energy strong interaction. Since its construction, the DAΦNE collider has represented an ideal machine to perform kaonic atoms measurements, thanks to the unique beam of kaons coming from the φs produced in the collider decays. The DEAR and SIDDHARTA experiments achieved the precise evaluation of the shift and width of the 2p → 1s transition in kaonic hydrogen due to the strong interaction, and thus provided a measurement strictly linked to isospin-dependent antikaon–nucleon scattering lengths. To fully disentangle the iso-scalar and iso-vector scattering lengths, the measurement of kaonic deuterium is necessary as well. The SIDDHARTA-2 experiment is now taking data at the DAΦNE collider with the aim to fulfill the need of this measurement, and therefore provide important information to the various phenomenological models on low-energy strong interactions with strangeness. The SIDDHARTA-2 Collaboration is also exploring the possibility to perform future kaonic atoms experiments, developing X-ray detector systems beyond the current state-of-art. These measurements are crucial for a deeper understanding of the kaon interactions with nuclei and for solving the kaon mass “puzzle”

Factor graph based detection approach for high-mobility OFDM systems with large FFT modes

In this article, a novel detector design is proposed for orthogonal frequency division multiplexing (OFDM) systems over frequency selective and time varying channels. Namely, we focus on systems with large OFDM symbol lengths where design and complexity constraints have to be taken into account and many of the existing ICI reduction techniques can not be applied. We propose a factor graph (FG) based approach for maximum a posteriori (MAP) symbol detection which exploits the frequency diversity introduced by the ICI in the OFDM symbol. The proposed algorithm provides high diversity orders allowing to outperform the free-ICI performance in high-mobility scenarios with an inherent parallel structure suitable for large OFDM block sizes. The performance of the mentioned near-optimal detection strategy is analyzed over a general bit-interleaved coded modulation (BICM) system applying low-density parity-check (LDPC) codes. The inclusion of pilot symbols is also considered in order to analyze how they assist the detection process