Date: Tue, 31 Jan 2006 13:22:28 +0100 (CET) From: Georges Audi To: Recipients of AMDC bulletin: ; Subject: AMDC - News from the Atomic Mass Data Center NEUTRINO MASS from 115In-115Sn by Vladimir Tretyak In a recent experiment [1], the beta decay of 115In to the first excited level of 115Sn was observed. The low probability of this decay (1.2e-6 relative to the ground state decay and half-life 3.7e20 years) is related with very small energy release, Q. The presently known Q value is 1.6(4.0) keV, from combining the 115In-115Sn atomic mass difference from Ame2003 of 499(4) keV [2] and the energy of the 115Sn first excited level at 497.4 keV. This is probably the lowest known Q value for observed beta decays. Because the mass of the neutrino, emitted in beta decay, cannot be greater than Q, such a situation has the potentiality to bring out a limit on neutrino mass, which could lay in the range of eV. The best way to clarify the situation would be an experimental measurement of the 115In-115Sn mass difference with a precision of ~100 eV [3]. 1. C.M. Cattadori et al., Nucl. Phys. A 748 (2005) 333. 2. G. Audi et al., Nucl. Phys. A 729 (2003) 337. 3. C.M. Cattadori et al., nucl-ex/0509020 (Phys. At. Nucl. in press). More info at: http://amdc.in2p3.fr/experimental/115in.txt MASS MEASUREMENTS at MIT by Edmund Myers "A direct test of E = mc2" Marking the end of the World Year of Physics the result of a direct test of Einstein's famous equation E = mc2 was published in Nature (S. Rainville et al. vol. 438, 1096 (2005). The test was based on the comparison of the neutron binding energies of 29Si and 33S, each obtained by precision Penning trap mass spectrometry ("m"), and by precision gamma-ray wavelength measurement ("E"). The atomic mass measurements were carried out by David Pritchard's group at MIT in early 2003 and used a novel technique with two ions in a single Penning trap. This enabled mass comparison at the unprecedented sub 1e-11 level. This work also marks the last of a series of major accomplishments by David Pritchard's MIT precision mass spectrometry group. More details in: http://amdc.in2p3.fr/experimental/mit-fl.txt MASS MEASUREMENTS at FLORIDA STATE UNIVERSITY by Edmund Myers In mid 2003 the MIT precision mass spectrometry group was disbanded and the apparatus moved to Florida State University, Tallahassee. The FSU group (Edmund Myers et al.) rebuilt the system and so far has used it for mass measurements of 32S, 84Kr, 86Kr, 129Xe and 132Xe using single ions in the Penning trap, see W. Shi et al, Phys. Rev. A72, 022510 (2005). They have also measured the mass of 31P, using two ions in a trap, but alternating between large and small cyclotron orbits, (IJMS, in press). Work on reproducing the two-ion simultaneous cyclotron frequency measurement technique at FSU is in progress. More details in: http://amdc.in2p3.fr/experimental/mit-fl.txt TENURE TRACK POSITION at the UNIV. OF MANITOBA by Kumar Sharma We have a new tenure track, assistant professor position at our university. The fields of interest include atomic mass determinations, ion traps, symmetry tests and other fields. I would very much appreciate it if you could forward this advertisement to any suitable candidates. Full info: http://amdc.in2p3.fr/experimental/manitoba.txt PAIRING ENERGIES In Ame'93 and Ame2003 we calculated pairing energies in tables available from the AMDC web (not published material): http://amdc.in2p3.fr/masstables/Ame1993/rct3_rmd.mas93 http://amdc.in2p3.fr/masstables/Ame2003/rct7.mas03 The quantities Dnn and Dpp are the neutron and proton pairing energies as defined in Ame'83, p.56. Unfortunately, the values given for the neutron-proton pairing energies (written Dnp in Ame'93, Pa in Ame2003) in these files do not correspond to the definition in Ame'83, p.56, but to an older definition which used only 2 Sd (deuton separation energies): 1/2(-1)**(Z)[-Sd(A+2,Z+1)+Sd(A,Z)] instead of 3: 1/4(-1)**(Z+1)[Sd(A+2,Z+1)-2Sd(A,Z)+Sd(A-2,Z-1)] Although the formula with 2 Sd is still correct, we believe the formula with 3 Sd to be better. We kindly ask those to used these np-pairing to accept our apologize, and be informed that the physics they derived from them is essentially unchanged. We thank Pr. Till von Egidy for pointing out the problem. NUCLEUS-WIN WITH PERSONAL DATA Several people could not compile their personal data and have them running with Nucleus-Win. This is due to one bug in the main program and another one in the installation program. A rapid solution is to create a new directory "Nubase" (besides "NubaseW") and put there file "Fat.if1": http://amdc.in2p3.fr/nucleus/Fat.if1 Sorry for the inconveniences this bug may have caused.