Abstract
Interests on few-body hypernuclei have been increased by recent results of experiments employing relativistic heavy ion beams. Some of the experiments have revealed that the lifetime of the ...lightest hypernucleus, hypertriton, is significantly shorter than 263 ps which is expected by considering the hypertriton to be a weakly-bound system. The STAR collaboration has also measured the hypertriton binding energy, and the deduced value is contradicting to its formerly known small binding energy. These measurements have indicated that the fundamental physics quantities of the hypertriton such as its lifetime and binding energy have not been understood, therefore, they have to be measured very precisely. Furthermore, an unprecedented Λnn bound state observed by the HypHI collaboration has to be studied in order to draw a conclusion whether or not such a bound state exists. These three-body hypernuclear states are studied by the heavy-ion beam data in the WASA-FRS experiment and by analysing J-PARC E07 nuclear emulsion data with machine learning.
The first excited 2+ states in 54,56,58Cr were populated by Coulomb excitation at relativistic energies and γ rays were measured using the RISING setup at GSI. For 56Cr and 58Cr the B(E2,21+→0+) ...values relative to the previously known B(E2) value for 54Cr are determined as 8.7(3.0) and 14.8(4.2) W.u., respectively. The results are consistent with a subshell closure at neutron number N=32 which was already indicated by the higher energy of the 21+ state in 56Cr. Recent large-scale shell model calculations using effective interactions reproduce the trend in the excitation energies, but fail to account for the minimum in the B(E2) values at N=32.
The feature-extraction algorithm, developed for the digital front-end electronics of the electromagnetic calorimeter of the PANDA detector at the future FAIR facility, is implemented in VHDL for a ...commercial 16 bit 100 MHz sampling ADC. The use of modified firmware with the running on-line data-processing algorithm will allow to perform realistic performance studies of the calorimeter and test a trigger-less readout concept of the data acquisition for the PANDA experiment.
The response of two generations of prototypes of the P¯ANDA Electromagnetic Calorimeter (EMC), PROTO60 and PROT120, to photons in the energy range between 50MeV and 800MeV was obtained. Furthermore, ...the performance of the pre-amplifier ASIC (APFEL) under real experimental conditions, the position dependence of the energy resolution within the crystal and the implementation of higher order energy correction algorithms with a 15GeV/c positron beam were studied.
Using the data sets taken at center-of-mass energies above 4 GeV by the BESIII detector at the BEPCII storage ring, we search for the reaction e+e−→γISRX(3872)→γISRπ+π−J/ψ via the Initial State ...Radiation technique. The production of a resonance with quantum numbers JPC=1++ such as the X(3872) via single photon e+e− annihilation is forbidden, but is allowed by a next-to-leading order box diagram. We do not observe a significant signal of X(3872), and therefore give an upper limit for the electronic width times the branching fraction ΓeeX(3872)B(X(3872)→π+π−J/ψ)<0.13 eV at the 90% confidence level. This measurement improves upon existing limits by a factor of 46. Using the same final state, we also measure the electronic width of the ψ(3686) to be Γeeψ(3686)=2213±18stat±99sys eV.
The response of two generations of prototypes of the View the MathML sourceP¯ANDA Electromagnetic Calorimeter (EMC), PROTO60 and PROT120, to photons in the energy range between 50 MeV and 800 MeV was ...obtained. Furthermore, the performance of the pre-amplifier ASIC (APFEL) under real experimental conditions, the position dependence of the energy resolution within the crystal and the implementation of higher order energy correction algorithms with a 15 GeV/c positron beam were studied.
The HypHI Phase 0 experiment with 6Li projectiles at 2A GeV on a carbon target has been performed at GSI in order to demonstrate the feasibility of precise hypernuclear spectroscopy with peripheral ...heavy ion collisions. Current data analyses have preliminary shown peaks in invariant mass distributions of p+π− for Λ, He3+π− for HΛ3 and He4+π− for HΛ4. Lifetime values for the corresponding peaks have been also deduced, which is in good agreement with the former known values.
For the investigation of the charmonium spectrum, yet undiscovered charm-meson states and glueballs, the PANDA detector will be employed at the future FAIR facility. PANDA will contain an ...electromagnetic calorimeter composed of PbWO 4 (PWO) crystals that are cooled to -25 ° C and coupled to large-area avalanche photodiodes or vacuum phototriodes/-tetrodes. The photosensor signals are continuously digitized by sampling analog-to-digital converters (SADCs) and analyzed online in field programmable gate arrays (FPGAs) that are part of the digitizer module to detect hits and extract energy and time information. The online SADC-data processing algorithm was designed, optimized, and implemented in VHDL for a Xilinx FPGA. In order to estimate the performance of the SADC readout of cooled PWO crystals, several measurements with tagged photons in the energy range of 60 MeV-1.4 GeV were performed. The digital readout improves the energy resolution in particular at low photon energies and simultaneously provides a time resolution below 1 ns for an energy deposition above 80 MeV. The successful application of the online data-processing procedure is an essential step toward the development of a trigger-less readout concept of the data acquisition for the PANDA experiment.
A simple, efficient, and robust on-line data-processing scheme was developed for the digital front-end electronics of the electromagnetic calorimeter of the PANDA spectrometer at FAIR, Darmstadt. The ...implementation of the processing algorithm in FPGA enables the construction of an almost dead-time free data acquisition system. The prototype of a complete trigger-less readout chain has been developed and evaluated. The precision of time synchronisation commands has been verified. A pile-up recovery algorithm was developed and evaluated over a large dynamic range of signal amplitudes.
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