Hypernuclear spectroscopy of products from Li-6 projectiles on a carbon target at 2 A GeV

WOS: 000322848900009
A novel experiment, aiming at demonstrating the feasibility of hypernuclear spectroscopy with heavy ion beams, was conducted. Using the invariant mass method, the spectroscopy of hypernuclear products of Li-6 projectiles on a carbon target at 2 A GeV was performed. Signals of the Lambda-hyperon and H-3(Lambda) and H-4(Lambda) hypernuclei were observed for final states of p + pi(-), He-3 + pi(-) and He-4 + pi(-), respectively, with significance values of 6.7, 4.7 and 4.9 sigma. By analyzing the proper decay time from secondary vertex distribution with the unbinned maximum likelihood fitting method, their lifetime values were deduced to be 262(-43)(+56) +/- 45 ps for Lambda, 183(-32)(+42) +/- 37 ps for H-3(Lambda), and 140(-33)(+48) +/- 35 ps for H-4(Lambda). (c) 2013 Elsevier B.V. All rights reserved.
Electronics Department of the Institute for Nuclear Physics of Mainz University; Helmholtz association as Helmholtz-University Young Investigators Group at GSI [VH-NG-239]; German Research Foundation (DFG) [SA 1696/1-1]; Ministry of Education, Science and Culture of Japan [18042008]; EU FP7 Hadron-Physics-2 SPHERE; GSI Department of Accelerator; GSI Department of Experimental Electronics; GSI Department of the Detector Laboratory; GSI Department of the Target Laboratory
The authors would like to thank the GSI Departments of Accelerator, of Experimental Electronics, of the Detector Laboratory and of the Target Laboratory and the Electronics Department of the Institute for Nuclear Physics of Mainz University for supporting the project. The HypHI project is funded by the Helmholtz association as Helmholtz-University Young Investigators Group VH-NG-239 at GSI, and the German Research Foundation (DFG) under contract number SA 1696/1-1. The authors acknowledge the financial support provided by the Ministry of Education, Science and Culture of Japan, Grant-in-Aid for Scientific Research on Priority Areas 449, and Grant-in-Aid for promotion of Cooperative Research in Osaka Electro-Communication University (2004-2006). This work is also supported by the Ministry of Education, Science and Culture of Japan, Grants-in-Aid for Scientific Research 18042008 and EU FP7 Hadron-Physics-2 SPHERE. A part of this work was carried out on the HIMSTER high performance computing infrastructure provided by the Helmholtz-Institute Mainz.