Abstract The production of $$\Sigma ^{0}$$ Σ 0 hyperons in proton proton collisions at a beam kinetic energy of 3.5 GeV impinging on a liquid hydrogen target was investigated using data collected ...with the HADES setup. The total production cross section is found to be $${\sigma (pK^{+}\Sigma ^{0}) = 17.7 \pm 1.7 (stat) \pm 1.6 (syst)}$$ σ ( p K + Σ 0 ) = 17.7 ± 1.7 ( s t a t ) ± 1.6 ( s y s t ) µb. Differential cross section distributions of the exclusive channel $${pp \rightarrow pK^{+}\Sigma ^{0}}$$ p p → p K + Σ 0 were analyzed in the center-of-mass, Gottfried–Jackson and helicity reference frames for the first time at the excess energy of 556 MeV. The data support the interplay between pion and kaon exchange mechanisms and clearly demonstrate the contribution of interfering nucleon resonances decaying to $$\textrm{K}^{+}\Sigma ^{0}$$ K + Σ 0 . The Bonn–Gatchina partial wave analysis was employed to analyse the data. Due to the limited statistics, it was not possible to obtain an unambiguous determination of the relative contribution of intermediate nucleon resonances to the final state. However nucleon resonances with masses around 1.710 $${\textrm{GeV}/\textrm{c}^{2}}$$ GeV / c 2 ( $${\textrm{N}^{*}(1710)}$$ N ∗ ( 1710 ) ) and 1.900 $${\textrm{GeV}/\textrm{c}^{2}}$$ GeV / c 2 ( $${\textrm{N}^{*}(1900)}$$ N ∗ ( 1900 ) or $${\Delta ^{*}(1900)}$$ Δ ∗ ( 1900 ) ) are preferred by the fit.
The production of
Σ
0
hyperons in proton proton collisions at a beam kinetic energy of 3.5 GeV impinging on a liquid hydrogen target was investigated using data collected with the HADES setup. The ...total production cross section is found to be
σ
(
p
K
+
Σ
0
)
=
17.7
±
1.7
(
s
t
a
t
)
±
1.6
(
s
y
s
t
)
µb. Differential cross section distributions of the exclusive channel
p
p
→
p
K
+
Σ
0
were analyzed in the center-of-mass, Gottfried–Jackson and helicity reference frames for the first time at the excess energy of 556 MeV. The data support the interplay between pion and kaon exchange mechanisms and clearly demonstrate the contribution of interfering nucleon resonances decaying to
K
+
Σ
0
. The Bonn–Gatchina partial wave analysis was employed to analyse the data. Due to the limited statistics, it was not possible to obtain an unambiguous determination of the relative contribution of intermediate nucleon resonances to the final state. However nucleon resonances with masses around 1.710
GeV
/
c
2
(
N
∗
(
1710
)
) and 1.900
GeV
/
c
2
(
N
∗
(
1900
)
or
Δ
∗
(
1900
)
) are preferred by the fit.
The amount of data coming from modern acquisition systems, especially working in extreme experimental conditions, is significantly rising over the years. Combined with complex algorithms, the ...computation time and power consumption are considerably increasing. The issue usually occurs in many world laboratories, such as CERN, Brookhaven National Laboratory, GSI Helmholtzzentrum für Schwerionenforschung, and tokamak devices (JET, WEST, MAST, and more). Often well verified, but legacy codes are used as a main computational engine, resulting in weak performance unsuitable for current needs. The paper presents a methodology to appropriately adapt the legacy C/C++ high-energy physics (HEP) algorithms for computation acceleration using FPGAs, which may improve the designing of real-time systems based on verified codes. The main idea is to separate the HLS-FPGA code work areas between groups of experts: physicists and electronics. The methodology consists of several parts: interfacing, storage, verification methods, defining the algorithm and data structures, program refactoring in the scope of CPU and FPGA, performance and results analysis, FPGA verification methods, FPGA performance estimation, and automatization of the process. The methodology has been successfully tested by implementing a legacy, complex HEP algorithm for femtoscopy correlations in the HLS framework for FPGA. It works with extensive input data from international experiments, like STAR at RHIC. The implementation and verification were done successfully on the FPGA hardware platform. Following the methodology results in a clearer to analyze and debug HEP code than a machine-generated version by tools. We also confirmed that it is possible to make a working, HLS-compliant program designed by non-FPGA experts. Using the modern implementation tools, FPGA resource usage is low despite unoptimized syntax. It gives a large field for further significant optimizations and good performance. The proposed approach should be interesting to introduce in devices like tokamaks, synchrotrons, and similar, where the real-time monitoring of the experimental processes is essential.
•Methodology for complex algorithm conversion from legacy code to hardware accelerated in FPGA in high level synthesis (HLS) languages.•Guidelines to achieve the performance improvement of legacy (C, Fortran etc.) high energy physics algorithms.•Discussion about the pros and cons of using the high-level synthesis (HLS) languages for acceleration.•Preliminary in-hardware FPGA laboratory tests of the presented approach based on Monte-Carlo HEP algorithm for heavy-ion collisions.•Use for high energy physics experiments, however not limited to.
The global polarization of Λ hyperons along the total orbital angular momentum of a relativistic heavy-ion collision is presented based on the high statistics data samples collected in Au+Au ...collisions at sNN=2.4 GeV and Ag+Ag at 2.55 GeV with the High-Acceptance Di-Electron Spectrometer (HADES) at GSI, Darmstadt. This is the first measurement below the strangeness production threshold in nucleon-nucleon collisions. Results are reported as a function of the collision centrality as well as a function of the hyperon's transverse momentum (pT) and rapidity (yCM) for the range of centrality 0–40%. We observe a strong centrality dependence of the polarization with an increasing signal towards peripheral collisions. For mid-central (20 – 40%) collisions the polarization magnitudes are 〈PΛ〉(%)=6.8±1.3(stat.)±2.1(syst.) for Au+Au and 〈PΛ〉(%)=6.2±0.4(stat.)±0.6(syst.) for Ag+Ag, which are the largest values observed so far. This observation thus provides a continuation of the increasing trend previously observed by STAR and contrasts expectations from recent theoretical calculations predicting a maximum in the region of collision energies about 3 GeV. The observed polarization is of a similar magnitude as predicted by 3D-fluid-dynamics and the UrQMD plus thermal vorticity model and significantly above results from the AMPT model.
The double differential production cross sections, \(d^2\sigma/d\Omega dE\), for hydrogen isotopes and charged pions in the reaction of p + Nb at 3.5 GeV proton beam energy have been measured by the ...High Acceptance DiElectron Spectrometer (HADES). Thanks to the high acceptance of HADES at forward emission angles and usage of its magnetic field, the measured energy range of hydrogen isotopes could be significantly extended in comparison to the relatively scarce experimental data available in the literature. The data provide information about the development of the intranuclear cascade in the proton-nucleus collisions. They can as well be utilized to study the rate of energy/momentum dissipation in the nuclear systems and the mechanism of elementary and composite particle production in excited nuclear matter at normal density. Data of this type are important also for technological and medical applications. Our results are compared to models developed to describe the processes relevant to nuclear spallation (INCL++) or oriented to probe either the elementary hadronic processes in nuclear matter or the behavior of compressed nuclear matter (GiBUU).
Microstructure, revealed by X-ray diffraction, transmission electron microscopy and Mössbauer spectroscopy, and magnetic properties such as magnetic susceptibility, its disaccommodation, core losses ...and approach to magnetic saturation in bulk amorphous (Fe0.61Co0.10Zr0.025Hf0.025Ti0.02W0.02B0.20)100−xYx (x=0, 2, 3 or 4) alloys in the as-cast state and after the annealing in vacuum at 720K for 15min. are studied. The investigated alloys are ferromagnetic at room temperature. The average hyperfine field induction decreases with Y concentration. Due to annealing out of free volumes its value increases after the heat treatment of the samples. The magnetic susceptibility and core losses point out that the best thermal stability by the amorphous (Fe0.61Co0.10Zr0.025Hf0.025Ti0.02W0.02B0.20)97Y3 alloy is exhibited. Moreover, from Mössbauer spectroscopy investigations it is shown that the mentioned above alloy is the most homogeneous. The atom packing density increases with Y concentration, which is proved by the magnetic susceptibility disaccommodation and approach to magnetic saturation studies.
▶ Microstructure and magnetic properties of amorphous. ▶ Fe0.61Co0.10Zr0.025Hf0.025Ti0.02W0.02B0.20)100−xYx (x=0, 2, 3 or 4) rods in the as-cast state. ▶ After the annealing at 720K for 15min are studied. ▶ The best thermal stability exhibits the alloy with x=3. ▶ The atom packing density increases with yttrium concentration.
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