First test of energy response of the micro-vertex detection system for the WASA-FRS Experiments

4 pags., 6 figs.The hypernuclei, which are nuclei that contain the quark s, have been studied for more than 50 years. Notwithstanding, the recent experiments using high-energy heavy-ion induced reactions have challenged their current understanding. The high multiplicity of particles generated in the reaction allows for the measurement of the interaction point of the primary beam with the target. Then, a micro-vertex detection system for the WASA-FRS Experiments has been developed. Several experimental tests have been performed with 90Sr and 207Bi β sources and a 10-MeV proton beam at the CMAM tandem accelerator, and their results are reported.This work is supported by the grants 2019-T1/TIC-13194 and 2023- 5A/TIC-28925 of the program ‘Atracción de Talento Investigador’ of the Comunidad de Madrid, and by the grant PID2020-118009GA-I00 of the ‘Proyectos I+D+i 2020’ of the Agencia Estatal de Investigación (Gobierno de España).Peer reviewe

A compact start time counter using plastic scintillators readout with MPPC arrays for the WASA-FRS HypHI experiment

9 pags., 12 figs.We have developed a compact detector for measuring beam particles using plastic scintillators readout through Multi-Pixel Photon Counters, which is employed for hypernuclear measurements in the WASA-FRS experiment at GSI. The Time-of-Flight resolution of the newly-developed detector has been investigated in relation to the overvoltage with respect to the breakdown voltage, a maximum counting rate of approximately 3×106/s per segment, and a maximum beam charge of Z = 6. The evaluated Time-of-Flight resolutions between the neighboring segments of the detector range from 44.6±1.3 ps to 100.3±3.6 ps (σ) depending on the segment, overvoltage values, and beam intensity. It is also observed that the Time-of-Flight resolution is inversely correlated to the beam atomic charge (Z).The WASA-FRS project is supported by the JSPS KAKENHI, Japan (Grant Numbers JP18H01242), the JSPS Grant-in-Aid for Early-Career Scientists (Grant No. JP20K14499), the JSPS Fostering Joint International Research (B) (Grant No. JP20KK0070), Proyectos I+D+i 2020 ref: PID2020-118009GA-I00 ; grant 2019- T1/TIC-13194 of the program Atracción de Talento Investigador of the Community of Madrid, the Regional Government of Galicia under the Postdoctoral Fellowship Grant No. ED481D-2021-018, the ‘‘Ramón y Cajal’’ program under the Grant No. RYC2021-031989-I, the SciMat and qLife Priority Research Areas budget under the program Excellence Initiative - Research University at the Jagiellonian University and the European Unions Horizon 2020 research and innovation programme under grant agreement No 824093. The project is also supported by the JustusLiebig-Universität (JLU), Gießen, Germany, and GSI, Germany under the JLU-GSI strategic Helmholtz partnership agreement. This research is supported in part by the ExtreMe Matter Institute EMMI at the GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt, Germany.Peer reviewe

Study of hypernuclei in the reaction 6Li+ I2C at 2 A Oe V

Cette thèse présente une nouvelle approche expérimentale proposée par la collaboration HypHI pour l’étude des hypernoyaux dans des réactions induites par des faisceaux d’ions lourds stables ou radioactifs. La méthode proposée permet de mesurer les hypernoyaux formés par coalescence entre un hypéron Λ produit dans la région des participants et un fragment spectateur issu du projectile. Ce mode de production offre la possibilité d’étudier les hypernoyaux dans des conditions extrêmes d’isospin et de mesurer directement leur moment magnétique hypernucléaire. Une première expérience ayant pour objectif principal de démontrer la faisabilité de la nouvelle méthode proposée, a été réalisée en effectuant une spectroscopie précise des hypernoyaux 4 ΛH, 3 ΛH et 5 ΛHe produits dans les collisions 6Li+12C à une énergie incidente de 2 GeV par nucléon. La conception, le développement et la réalisation du nouveau dispositif de détection sont présentés. Les performances des détecteurs, ainsi que celles du système de déclenchement ont été étudiées. Le code d’analyse développé pour la reconstruction des hypernoyaux est présenté ainsi que ses performances sur les données simulées. L’analyse des données expérimentales et les premiers résultats de la reconstruction de l’hypéron Λ et de l’hypernoyau 5 ΛHe, ainsi que la mesure de leur temps de vie, sont présentés. Ces premiers résultats démontrent la faisabilité de cette nouvelle approche expérimentale pour l’étude des hypernoyaux et ouvrent de nouvelles perspectives dans la recherche d’hypernoyaux lourds et proches des limites de stabilité.This thesis presents a new experimental approach proposed by the HypHI collaboration to study hypernulei by means of reactions induced by stable and radioactive heavy-ion beams. The proposed method allows to measure hypernuclei formed by coalescence of a Λ-hyperon produced in the participant region and a projectile spectator fragment. Such a production mode offers the opportunity to investigate hypernuclei at extreme isospin and to measure directly hypernuclear magnetic moments. A first experiment aiming at demonstrating the feasibility of this new method has been carried out with a 6Li beam at 2 A GeV impinged on a 12C target by identifying 3 ΛH, 4 ΛH and 5 ΛHe hypernuclei from their mesonic weak decay modes. The design, development and realization of this experiment are presented. Performances of the detectors and of the trigger system have been investigated. The software analysis developed for the reconstruction of hypernuclei is presented and its performances are evaluated using simulated data. The data analysis and preliminary results of the reconstruction of Λ hyperons and of 5 ΛHe and the measurement of their lifetime are reported. The results demonstrate the feasibility of the new experimental approach for the study of hypernuclei and open new perspectives to investigate heavier hypernuclei toward the proton and neutron drip lines

Studies of hypernuclei with heavy-ion beams, nuclear emulsions and machine learning - T. R. Saito, for the WASA-FRS collaboration and the Emulsion-ML collaboration

Presentación con 75 diapositivas, HYP2022, June 27th – July 1st, Prague, 2022The lightest hypernucleus, the hypertriton, has been a benchmark in the field of hypernuclear physics. However, some of recent experiments employing energetic heavy-ion beams have revealed that the hypertriton lifetime is significantly shorter than 263 ps which is expected by considering the known weakly binding nature of the hypertriton. 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 learnin

Étude des hypernoyaux dans la réaction 6Li+12C à 2 GeV/nucléon

Cette thèse présente une nouvelle approche expérimentale proposée par la collaboration HypHI pour l'étude des hypernoyaux dans des réactions induites par des faisceaux d'ions lourds stables ou radioactifs. La méthode proposée permet de mesurer les hypernoThis thesis presents a new experimental approach proposed by the HypHI collaboration to study hypernulei by means of reactions induced by stable and radioactive heavy-ion beams. The proposed method allows to measure hypernuclei formed by coalescence of

Étude des hypernoyaux dans la réaction 6Li+12C à 2 GeV/nucléon

Cette thèse présente une nouvelle approche expérimentale proposée par la collaboration HypHI pour l'étude des hypernoyaux dans des réactions induites par des faisceaux d'ions lourds stables ou radioactifs. La méthode proposée permet de mesurer les hypernoyaux formés par coalescence entre un hypéron produit dans la région des participants et un fragment spectateur issu du projectile. Ce mode de production offr la possibilité d'étudier les hypernoyaux dans des conditions extrêmes d'isospin et de mesurer directement leur moment magnétique hypernucléaire. Une première expérience ayant pour objectif principal de démontrer la faisabilité de la nouvelle méthode proposée, a été réalisée en effectuant une spectroscopie précise des hypernoyaux 4 H, 3 H et 5 He produits dans les collisions 6Li+12C à une énergie incidente de 2 GeV par nucléon. La conception, le développement et la réalisation du nouveau dispositif de détection sont présentés. Les performances des détecteurs, ainsi que celles du système de déclenchement ont été étudiées. Le code d'analyse développé pour la reconstruction des hypernoyaux est présenté ainsi que ses performances sur les données simulées. L'analyse des données expérimentales et les premiers résultats de la reconstruction de l'hypéron et de l'hypernoyau 5 He, ainsi que la mesure de leur temps de vie, sont présentés. Ces premiers résultats démontrent la faisabilité de cette nouvelle approche expérimentale pour l'étude des hypernoyaux et ouvrent de nouvelles perspectives dans la recherche d'hypernoyaux lourds et proches des limites de stabilité.This thesis presents a new experimental approach proposed by the HypHI collaboration to study hypernulei by means of reactions induced by stable and radioactive heavy-ion beams. The proposed method allows to measure hypernuclei formed by coalescence of a -hyperon produced in the participant region and a projectile spectator fragment. Such a production mode offers the opportunity to investigate hypernuclei at extreme isospin and to measure directly hypernuclear magnetic moments. A first experiment aiming at demonstrating the feasibility of this new method has been carried out with a 6Li beam at 2 A GeV impinged on a 12C target by identifying 3 H, 4 H and 5 He hypernuclei from their mesonic weak decay modes. The design, development and realization of this experiment are presented. Performances of the detectors and of the trigger system have been investigated. The software analysis developed for the reconstruction of hypernuclei is presented and its performances are evaluated using simulated data. The data analysis and preliminary results of the reconstruction of hyperons and of 5 He and the measurement of their lifetime are reported. The results demonstrate the feasibility of the new experimental approach for the study of hypernuclei and open new perspectives to investigate heavier hypernuclei toward the proton and neutron drip lines

Production Optimization of Exotic Hypernuclei via Heavy-Ion Beams at GSI-FAIR

Building on the successful demonstration of hypernuclear spectroscopy using heavy-ion beams, the HypHI Collaboration is shifting its focus to investigating proton- and neutron-rich hypernuclei. A crucial component of this research is the implementation of a fragment separator, which facilitates the production and separation of rare isotope beams and is vital for accessing hypernuclei far from the stability line. High-precision spectroscopy of these exotic hypernuclei is planned to be conducted at GSI first, which will be followed by experiments at the FAIR facility utilizing the FRS and Super-FRS fragment separators. A thorough systematic investigation paired with an optimization analysis was employed to establish the most favorable experimental setup for producing high-isospin hypernuclei. Theoretical models describing heavy-ion-induced reactions and hypernuclear synthesis guided this process, which was complemented by Monte Carlo simulations to obtain experimental efficiencies for the production and transmission of the exotic secondary beams. The outlined methodology offers insights into the anticipated yields of HeΛ6, CΛ9, and a range of both proton- and neutron-rich hypernuclei

WASA-FRS HypHI experiment at GSI for studying light hypernuclei - Hiroyuki Ekawaa for WASA-FRS Collaboration

Presentación con 17 dispositivas. -- 5 pags. 4 figs., 2 tabs. -- HYP2022 - 14th International Conference on Hypernuclear and Strange Particle Physics. From January till March 2022, the WASA-FRS HypHI experiment performed a precise measurement of the hypertriton and the 4 ΛH hypernucleus lifetime at GSI. The data collected should also confirm whether or not the nnΛ bound state can exist. The experiment were carried out with the WASA central detector with a complex of additional dedicated detectors mounted together at the mid-focal plane of the high-momentum-resolution forward spectrometer, the so-called fragment separator FRS. Hypernuclei of interest were produced by induced reactions of 6Li projectiles at 1.96 A GeV on a diamond target with a thickness of 9.87 g/cm2 . Negatively charged π mesons from two-body decays of the hypernuclei of interest were measured by the WASA and the other detectors, and the residual nuclei after the π − decay were measured by the FRS with a momentum resolving power of 104