Study of doubly strange systems using stored antiprotons

Bound nuclear systems with two units of strangeness are still poorly known despite their importance for many strong interaction phenomena. Stored antiprotons beams in the GeV range represent an unparalleled factory for various hyperon-antihyperon pairs. Their outstanding large production probability in antiproton collisions will open the floodgates for a series of new studies of systems which contain two or even more units of strangeness at the P‾ANDA experiment at FAIR. For the first time, high resolution γ-spectroscopy of doubly strange ΛΛ-hypernuclei will be performed, thus complementing measurements of ground state decays of ΛΛ-hypernuclei at J-PARC or possible decays of particle unstable hypernuclei in heavy ion reactions. High resolution spectroscopy of multistrange Ξ−-atoms will be feasible and even the production of Ω−-atoms will be within reach. The latter might open the door to the |S|=3 world in strangeness nuclear physics, by the study of the hadronic Ω−-nucleus interaction. For the first time it will be possible to study the behavior of Ξ‾+ in nuclear systems under well controlled conditions

Decay studies of neutron-deficient lawrencium isotopes

The radioactive decay of the isotopes 254-256Lr and their daughter products was investigated by means of α , prompt α -γ and delayed conversion electron-γ coincidence spectroscopy. The isotopes were produced using the reaction 48Ca + 209Bi

Alpha-gamma decay studies of 258Db^{258}Db and its (grand)daughter nuclei 254Lr^{254}Lr and 250Md^{250}Md

International audienceThe superheavy isotope$^{258}$Db was produced in the$^{209}$Bi($^{50}$Ti, 1n)$^{258}$Db reaction at GSI, Germany. A detailed $\alpha$ -spectroscopy study of this isotope and its $\alpha$ -decay daughter products was performed. Two long-lived $\alpha$ -decaying states in$^{258}$Db are observed. A spin-parity of $0^{-}$ is tentatively assigned to the ground state for which a half-life of $2.17 \pm 0.36$ s is determined. Spins and parities of either $5^{+}$ or $10^{-}$ are proposed for the isomeric state found at an excitation energy of 51 keV with a half-life of $4.41 \pm 0.21$ s. The $\alpha$ -decay daughter isotope$^{254}$Lr displays a similar behavior. A half-life of $11.9 \pm 0.9$ s is determined for the$^{254}$Lr ground state which is tentatively assigned a spin-parity of $4^{+}$ . The isomeric level of this isotope placed at 108 keV with a half-life of $20.3 \pm 4.2$ s is tentatively assigned a spin-parity of $1^{-}$ . Two long-lived $\alpha$ -decaying states are observed in the granddaughter isotope$^{250}$Md . The ground state has a half-life of $59.5 \pm 9.1$ s. A half-life of $42.4 \pm 4.5$ s is measured for the isomeric state positioned at an excitation energy of 123 keV. Partial, tentative level schemes for$^{254}$Lr,$^{250}$Md and$^{246}$Es are proposed based on the $\alpha$ - $\gamma$ coincidences

The DESPEC setup for GSI and FAIR

The DEcay SPECtroscopy (DESPEC) setup for nuclear structure investigations was developed and commissioned at GSI, Germany in preparation for a full campaign of experiments at the FRS and Super-FRS. In this paper, we report on the first employment of the setup in the hybrid configuration with the AIDA implanter coupled to the FATIMA LaBr3(Ce) fast-timing array, and high-purity germanium detectors. Initial results are shown from the first experiments carried out with the setup. An overview of the setup and function is discussed, including technical advancements along the path.Peer ReviewedArticle signat per 169 autors/es. A.K. Mistry 1,2,∗, H.M. Albers 2, T. Arıcı 3, A. Banerjee 2, G. Benzoni 4, B. Cederwall 5, J. Gerl 2, M. Górska 2, O. Hall 6, N. Hubbard 1,2, I. Kojouharov 2, J. Jolie 7, T. Martinez 8, Zs. Podolyák 9, P.H. Regan 9,10, J.L. Tain 11, A. Tarifeno-Saldivia 12, H. Schaffner 2, V. Werner 1, G. Ağgez 3, J. Agramunt 11, U. Ahmed 1, O. Aktas 5, V. Alcayne 8, A. Algora 11,13, S. Alhomaidhi 1,2, F. Amjad 2, C. Appleton 6, M. Armstrong 7, M. Balogh 14, K. Banerjee 15, P. Bednarczyk 16, J. Benito 17, C. Bhattacharya 15, P. Black 6, A. Blazhev 7, S. Bottoni 4,18, P. Boutachkov 2, A. Bracco 18,4, A.M. Bruce 19, M. Brunet 9, C.G. Bruno 6, I. Burrows 20, F. Calvino 12, R.L. Canavan 9,10, D. Cano-Ott 8, M.M.R. Chishti 9, P. Coleman-Smith 20, M.L. Cortés 1, G. Cortes 12, F. Crespi 18,4, B. Das 5, T. Davinson 6, A. De Blas 12, T. Dickel 2, M. Doncel 21, A. Ertoprak 5,3, A. Esmaylzadeh 7, B. Fornal 16, L.M. Fraile 17, F. Galtarossa 14, A. Gottardo 14, V. Guadilla 11,22, J. Ha 23,24, E. Haettner 2, G. Häfner 25,7, H. Heggen 2, P. Herrmann 1, C. Hornung 2, S. Jazrawi 9,10, P.R. John 1, A. Jokinen 26, C.E. Jones 19, D. Kahl 6,27, V. Karayonchev 7, E. Kazantseva 2, R. Kern 1, L. Knafla 7, R. Knöbel 2, P. Koseoglou 1, G. Kosir 28, D. Kostyleva 2, N. Kurz 2, N. Kuzminchuk 2, M. Labiche 20, J. Lawson 20, I. Lazarus 20, S.M. Lenzi 23, S. Leoni 4,18, M. Llanos-Expósito 17, R. Lozeva 25, A. Maj 16, J.K. Meena 15, E. Mendoza 8, R. Menegazzo 24, D. Mengoni 14, T.J. Mertzimekis 29, M. Mikolajczuk 22,2, B. Million 4, N. Mont-Geli 12, A.I. Morales 11, P. Morral 20, I. Mukha 2, J.R. Murias 17, E. Nacher 11, P. Napiralla 1, D.R. Napoli 14, B.S. Nara-Singh 30, D. O’Donnell 30, S.E.A. Orrigo 11, R.D. Page 31, R. Palit 32, M. Pallas 12, J. Pellumaj 14, S. Pelonis 29, H. Pentilla 26, A. Pérez de Rada 8, R.M. Pérez-Vidal 14, C.M. Petrache 25, N. Pietralla 1, S. Pietri 2, S. Pigliapoco 24, J. Plaza 8, M. Polettini 4,18, C. Porzio 4,18, V.F.E. Pucknell 20, F. Recchia 23, P. Reiter 7, K. Rezynkina 24, S. Rinta-Antila 26, E. Rocco 2, H.A. Rösch 2,1, P. Roy 15,2, B. Rubio 11, M. Rudigier 1, P. Ruotsalainen 26, S. Saha 33, E. Şahin 1,2, Ch. Scheidenberger 2, D.A. Seddon 31, L. Sexton 6, A. Sharma 34, M. Si 25, J. Simpson 20, A. Smith 35, R. Smith 20, P.A. Söderström 27, A. Sood 5, A. Soylu 36, Y.K. Tanaka 37, J.J. Valiente-Dobón 14, P. Vasileiou 29, J. Vasiljevic 5, J. Vesic 28, D. Villamarin 8, H. Weick 2, M. Wiebusch 2, J. Wiederhold 1, O. Wieland 4, H.J. Wollersheim 2, P.J. Woods 6, A. Yaneva 7, I. Zanon 14, G. Zhang 23,24, J. Zhao 2,38, R. Zidarova 1, G. Zimba 26, A. Zyriliou 29Postprint (author's final draft

Status of the rising project at relativistic energies

The RISING project was designed to perform high-resolution gamma-ray spectroscopy with radioactive beams at GSI. Unstable beams were produced by fragmentation of relativistic heavy ion projectiles provided by the SIS synchrotron. The fragment separator FRS was used to select and to focus the exotic fragments at about 100A MeV energy on a secondary target. Various charged particle detectors enabled an event-by-event tracking of the incoming radioactive projectiles and the reaction products, thus allowing for a selection of the nuclei of interest and their velocity vector reconstruction. The gamma-ray detection system consisting of the EUROBALL Cluster Ge detectors and the large volume HECTOR BaF2 detectors measured prompt gamma-radiation from nuclei excited in the secondary target. Despite the huge Doppler shift due to the high recoil velocity (beta approximate to 40%), RISING achieved a gamma-energy resolution below 2%. The paper reviews the present status of the RISING project