Chiara, C.J.

Janssens, R.V.F.

Lister, C.J.

Pechenaya, O.L.

Reviol, W.

Sarantites, D.G.

Seweryniak, D.

Carolina Digital Repository

PHYSICAL REVIEW C 78, 039804 (2008)Reply to “Comment on ‘Level structure of 92Rh: Implications for the two-proton decay of 94Agm’”O. L. Pechenaya*Department of Physics, Washington University, St. Louis, Missouri 63130, USAD. G. Sarantites and W. ReviolDepartment of Chemistry, Washington University, St. Louis, Missouri 63130, USAC. J. ChiaraNuclear Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, USAR. V. F. Janssens, C. J. Lister, and D. SeweryniakPhysics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA(Received 12 May 2008; published 22 September 2008)We reply to the preceding Comment.DOI: 10.1103/PhysRevC.78.039804 PACS number(s): 23.20.Lv, 23.50.+z, 23.20.En, 27.60.+jThe Comment by Mukha et al. about our recent publication[1] presents some interesting opinions, but no factual evidenceagainst our conclusions. These conclusions were reached onthe basis of both spectroscopic data and a Q-value calculationpartially dependent on extrapolated mass excess values. Theuse of Atomic Mass Evaluation (AME) [2] tables (includingtheir extrapolations) as a basis for our knowledge of the masssurface is a scientifically sound and standard method in ourfield, as is presenting deviations from the tabulated values.While we completely agree that this issue of the exact valuesof the mass excess will be finally resolved by new massmeasurements, we find it hard to see our paper as “misleading”in using these tabulated values, especially when supportedby spectroscopic data. It could be argued that the originalarticle [3] was incomplete, since the authors did not considerthe implications of their experiment in the light of the currentmass tables.Until new direct mass measurements are made, there seemsto be little new to discuss. We need only point out thatfor the most plausible case (based on angular-momentumconservation) of two-proton decay from 94Agm based on data*Present address: Department of Radiation Oncology,Washington University School of Medicine, St. Louis, Missouri63130, USA.in Ref. [3], the difference between the mass excess valuesof 92Rh and 93Pd (the only extrapolated values used) mustincrease by ∼2.7 MeV. In this case, the two protons couldpopulate a state (not observed in our data) of 2.947 MeV witha spin of 15h̄. This means that the two protons would carry sixunits of angular momentum, which is the only case consistentwith the reported partial half-life of 80+110−30 sec, assuming adeformation with an axis ratio of 3:1 [3]. The calculatedexcitation energy E∗ of 92Rh available in the reaction is0.24(57) MeV, and depends on the difference in mass excessvalues of 92Rh and 93Pd. We may express the problem thus:E∗(92Rh) = [(93Pd) − (92Rh)] + C, where C representsthe other (experimentally known) values used. The excitationenergy of their most plausible case is different from thecalculated value by 2.947 − 0.24(57) = 2.71(57) MeV, theamount of increase mentioned above.As a side note, we would like to point to a recent experimentwith the Canadian Penning Trap Spectrometer at ArgonneNational Laboratory [4] produced a preliminary result forthe mass excess of 92Rh. This result is within the rangeof the AME value, with an experimental uncertainty tentimes smaller than the uncertainty of that value. A recentexperiment at Jyväskylä [5] confirms our analysis on basisof 92Rh and 94Pd mass excesses, and in fact states an evenlower excitation energy of 92Rh accessible by the two-protondecay.[1] O. L. Pechenaya et al., Phys. Rev. C 76, 011304(R)(2007).[2] A. H. Wapstra, G. Audi, and C. Thibault, Nucl. Phys. A729, 129(2003).[3] I. Mukha et al., Nature (London) 439, 298 (2006).[4] G. Savard, private communication (2008).[5] A. Kankainen et al., http://arxiv.org/PS cache/arxiv/pdf/0804/0804.4743v1.pdf (2008).0556-2813/2008/78(3)/039804(1) 039804-1 ©2008 The American Physical Society

Reply to "comment on 'Level structure of Rh92: Implications for the two-proton decay of 94Agm'"

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Reply to "comment on 'Level structure of Rh92: Implications for the two-proton decay of 94Agm'"

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