Speaker
Daniel McNeel
(University of Connecticut)
Description
We have studied the ground state of the extremely neutron-rich isotope of hydrogen, $^{5}$H, using the $^{6}$He(d,$^{3}$He)$^{5}$H reaction in inverse kinematics. Several measurements exist for $^{5}$H (see Ref. [1]), however different results are in conflict with each other and with many theoretical predictions. The present measurement provides a clear evidence for the $^{5}$H ground state, and the previously unreported $^{6}$He(d,t)$^{5}$He ground state reaction is observed in the same experiment. A $^{6}$He beam at 55 AMeV produced at the National Superconducting Cyclotron Laboratory at Michigan State University bombarded a 1.9 mg/cm$^{2}$ (CD$_{2}$)n target. The reaction products were detected with HiRA (the High Resolution Array) [2]. The properties of the $^5$He ground state are well known from neutron scattering and the $^4$He(d,p)$^5$He reaction and provide information about the calibration and response of the apparatus. The $^3$He and $^3$H particles from the $^6$He(d,$^3$He/$^3$H)$^5$H/$^5$He reactions were detected in coincidence with the decay products of the unstable $^5$H and $^5$He nuclei, providing clean signatures for the transitions of interest. The data reveal clear evidence of the $^5$H ground-state resonance at an energy of 2.4±0.4 MeV above the threshold for decay into t+2n, with a width of 4.4±0.4 MeV. Details of the measurement, and a comparison of the results with those of previous measurements and theoretical calculations, will be presented.
[1] L. V. Grigorenko, Eur. Phys. J. A 20, 419 (2004) and references therein.
[2] M. S. Wallace et al., Nucl. Instrum. and Meth. A 583, 302 (2007).
| Funding Agency | Work supported by the U.S. Department of Energy under Contracts DE-FG02-04ER41320 and DE-FG02-87ER40316, DE-SC0014552 and the U. S. National Science Foundation under Grant Numbers PHY-1068217 and PHY-1068192. |
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Primary authors
Dr
Alan Wuosmaa
(University of Connecticut)
Daniel McNeel
(University of Connecticut)
Dr
Shadi Bedoor
(Texas A&M University)
Co-authors
A.S. Newton
(Western Michigan University)
Dr
D.V. Shetty
(Grand Valley State University)
Dr
J. R. Winkelbauer
(Michigan State University)
Juan Manfredi
(Michigan State University)
Kyle Brown
(Washington University at St. Louis)
Dr
L.G. Sobotka
(Washington University at St. Louis)
Dr
M. B. Tsang
(Michigan State University)
Dr
R. J. Charity
(Washington University at St. Louis)
Dr
R.H. Showalter
(Michigan State University)
Dr
S.T. Marley
(Louisiana State University)
Dr
W. W. Buhro
(Michigan State University)
Dr
W.G. Lynch
(Michigan State University)
Dr
Z. Chajecki
(Western Michigan University)
