DOCSLIB.ORG

(Two-Neutrino) Double Beta Decay and Related Processes J

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
(Two-Neutrino) Double Beta Decay and Related Processes J AN ESTIMATION OF THE RATES OF (TWO-NEUTRINO) DOUBLE BETA DECAY AND RELATED PROCESSES J. Abad, A. Morales, R. Núñez-Lagos, A. Pacheco To cite this version: J. Abad, A. Morales, R. Núñez-Lagos, A. Pacheco. AN ESTIMATION OF THE RATES OF (TWO- NEUTRINO) DOUBLE BETA DECAY AND RELATED PROCESSES. Journal de Physique Collo- ques, 1984, 45 (C3), pp.C3-147-C3-150. 10.1051/jphyscol:1984328. jpa-00224042 HAL Id: jpa-00224042 https://hal.archives-ouvertes.fr/jpa-00224042 Submitted on 1 Jan 1984 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. JOURNAL DE PHYSIQUE Colloque C3, suppl6ment au n03, Tome 45, mars 1984 page C3-147 AN ESTIMATION OF THE RATES OF (TWO-NEUTRINO) DOUBLE BETA DECAY AND RELATED PROCESSES J. Abad, A. Morales, R. ~df;ez-~a~osand A.F. Pacheco mstituto de ~&caNuclear y Altas Energiias, Universidad de Zaragoza, Zaragoza, Spain Rdsumd - La desintdgration double-bdta, la capture dlectronique avec dmission de positrons et la capture dlectronique double (tou'ours avec Bmission de dew neu- trinos) ont dtB calculdes en supposant que l'dtat 1' le plus bas du noyau intermd- diaire est dominant. En utilisant les valeurs expdrimentales pour les Bldments de matrice de dgsintdgration bQta simple et les ddnominateurs d'dnergie, on obtient des rBsultats qui ne ddpendent pas des calculs de physique nuclsaire. Les rBsultats pour la dssintdgration double-b6ta sont en accord avec les donndes gdochimiques rBcentes. D'autres prddictions sont 2 la portde des possibilitGs actuelles de dBtection. Abstract - The (two-neutrino) double beta decay, the electron capture with positron emission and the doubleelectroncapture decay rates are estimated for se- veral nuclides by assuming the dominance of the lowest 1+ state of the intermediate isobar. By using single-8 decay matrix elements and energy denominators as experi- mental imputs we get values independently of nuclear physics calculations. The re- sults for double 8- decay are in agreement with the recent geochemical values. Other predictions are within the present experimental sensitivity. The recent years have witnessed a great deal of work /1/ in the field of double be- ta decay because of its relevance for the question of the,(Plajorana) neutrino mass which might be inferred if the lepton number violating neutrinoless double beta de- cay would take place. From the theoretical point of view there exists alarming dis- crepancies /2/ between the conventional (28)-decay theory and the geochemical measu- rements /3,4,5/. Although it is commonly accepted that the uncertainties in the computations arise mainly from the nuclear matrix elements it is troubling to note that recent improved calculations with the state-of-the-art shell model techniques have exacerbated these discrepancies /2,6/. Moreover, the proper treatment /2,7/ of the Coulomb correction amounts also to an increase of the absolute rates, i.e.,each new refinement seems to go in the wrong direction. In the direct experiments there exists, so far, one "positive" result 181, in the 82~ecase, which is in contradic- tion with the corresponding geochemical result 161. On the other hand, there are two geochemical experiments /3,4/ measuring the famous Tellurium ratio which give incompatible results of far reaching consequences /2,4,7/. Should the geochemical results /4,5/ be correct one is faced to the uneasy situation of having theoretical absolute rates considerably larger than the experimental ones and, which is worse, all the theoretical improvements make the rates even larger. One might give up some of the approximations usually made in computing the rates, like for instance, the closure approximation employed when performing the sum over the intermediate nuclear states /6,9/ or to look for alternative mechanisms in order to reduce the theoretical rates /lo/. In Ref 6, devoted to the Te isotopes, the sum over the intermediate 1+ states is performed for excitation energies up to about 20 MeV, inserting LheahedXcdty campcLted single 8- and f.?+ decay amplitudes from the 0+ ground states to the various I+ intermediate states, instead of using the (28)-decay amplitudes conventionally surmned up by closure. With the nuclear states described in a BCS pairing model they obtain even higher rates than those previously computed Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1984328 C3-148 JOURNAL DE PHYSIQUE /2/. In Ref. 9 the sum over the intermediate states is saturated by keeping only %he lowest-lying 1+ state, inserting the expenimentae matrix elements of the single 8- and 6+ decay amplitudes from the 1+ to the 0+ ground states. This very naive and drastic a roach, as noted also in Ref. 6, already yields the observed 26-decay rates in the E58Te, 130~8and 82Se cases, as given by the geochemical data. These results may cast some doubts about the reliability of the geochemical measurements or the closure approximation, or both. In the present paper we briefly review our results /9/ and extend them to other two- neutrino processes related to the double beta decay, i.e. double positron emission, e- -+ e+ conversion and double electron capture Ill/. In the conventional (26)* decay theory the (two-neutrino) decay rate in O+ + 0+ transitions is given by 1 ~(68);, = (96a7)- (GFcos8) 4~4rn9 lMGT 1 2~$(years)-1 A=1.25 and S=<E,>-EI is the difference between the energy of the initial state and some averaged energy of the intermediate states. The Gamow-Teller matrix element is given as usual by GT It is straightforward to check that if one assumes the dominance of the 1' lowest- lying intermedia5e state,+one woukd obta&n, instead of MGT and S, respectively the quantities <OF 11 u 11 l><lll o 11 01>= M and !?=E~+-E~~which can be taken from the expe- rimental data. In fact, in the single-5 Gamow-Teller transitions l+ + 0+ one has where the indexes 1 and 2 refer to the two branches of decay from the intermediate state 1+ to the initial and final O+ ground states. The resulting half-life is T~/~(BB)~,= (4.26~10'~)/( ]GI2 1') years The phase space integrals I* have been computed numerically, with the Coulomb correc -tion --- factors F* as suggested by Haxton et a1 121. Table 1 shows the half-life pre- Nuclide (log ft)l (log ft)2 'I,s/m laGTI2 I TlI2(years) TABLE 1 i n 4 4 3 8 6 6 4 6 2 2 2 2 2 2 2 2 3 3 ) 2 2 2 2 0 0 0 (yr 1/2 1.4xl0 1.8xl0 2.1xl0 l.lxlO 8.3x1 3.9xl0 3.7x1 x 7.3xl0 6.4xl0 6.5x1 2.5xl0 2 2 5 - v 2 5 5 2 3 0 0 3 4 h (KK) 3. 2.4 7. 0.9 0.31 10.3 12. 21. 1.3xl0 2.2xl0~ 4.4xl0~ m 3 4 8 0 9 4 8 1 4 9 3 0 / 1.2 1.4 3.3 3.6 3.1 2.1 4.9 4.5 5.5 5.3 0.4 T 6 4 6 4 4 4 z 4 2 2 2 Z z 2 3 2 4 2 ) 2 2 (yr - - - 1/2 1.7xl0 3.0xl0 2.8xl0 T 6.4xl0 2.2xl0 6.8xlO 5.2xlO 4.4xl0 1 2 1 9 _ - - v 2 " + ) 0 0 4 7 - - h - 1. 3. (K6 12. 16. 0.59x10 0.44xl0 0.70xl0~ 0.40xl0 m 0 2 7 0 6 1 9 3 - - / 0 - 1.5 1.7 1.2 2.9 2.6 3.6 3.3 T 0.1 1 3 0 7 ) 7 3 2 2 0 0 0 (yr - - - - - - - 1/2 T 2.61x1 7.07x1 2.86x1 9.55xl0 3 5 3 7 v - 2 - h - - - - - - (eV) 0.358xl0~ 0.39xl0 0.206xl0~ 0.835xl0~ m 4 0 4 4 - / - - - 0 - - - 1.6 1.4 1.0 0.7 T 2 4 6 0 2 9 3 3 m 6 5 9 s/ 1.9 1.5 1.3 1.8 2.2 2.9 3.5 3.0 2.1 2.3 4.2 l 2 3 2 3 3 3 3 3 2 2 - - - 2 1 I M 1 GT I 1.14xl0 1.14xl0~ 3.61xl0~ 7.22xl0~ 7.22xl0~ 2.28x10" 3.62xl0" 7.22xl0~ 4.55xl0" 4.55xl0 9.08xl0 2 6 1 5 4 4 1 3 4 5 - - 5. 5. 4. 4. 4. 5. 5. 5. 5. log(ft) 1 0 0 1 7 6 5 8 8 9 - - 4. 5. 5. 4. 4. 4. 5. 4. 4. log(ft) e e a a n r e d r d L E B B S C C K C n e e e r r , „ B Z C C K T F 2 78 68 48 58 138 162 64 36 48 50 56 56 58 120 136 5 3Q 130, 132 Nuclid C3-150 JOURNAL DE PHYSIQUE dictions for (24)5v decay in some nuclides where the 1+ intermediate-state-dominan- ce-hypothesis is applicable. As it was said above the results are in fair agreement with the geochemical data for the 128~e,130Te and 82~e(28)- decay cases.
Load more

Recommended publications
  • CME Search Before Isobar Collisions and Blind Analysis from STAR
    CME Search Before Isobar Collisions and Blind Analysis From STAR Prithwish Tribedy for the STAR collaboration The 36th Winter Workshop on Nuclear Dynamics 1-7th March, 2020, Puerto Vallarta, Mexico In part supported by Introduction Solenoidal Tracker at RHIC (STAR) RHIC has collided multiple ion species; year 2018 was dedicated to search for effects driven by strong electromagnetic fields by STAR Isobars: Ru+Ru, Zr+Zr @ 200GeV (2018) Low energy: Au+Au 27 GeV (2018) Large systems : U+U, Au+Au @ 200 GeV P.Tribedy, WWND 2 The Chiral Magnetic Effect (Cartoon Picture) Quarks Quarks randomly aligned oriented along B antiquarks I II III IV More More right left handed handed quarks quarks J || B J || -B CME converts chiral imbalance to observable electric current P.Tribedy, WWND 2020 3 New Theory Guidance : Complexity Of An Event Magnetic field map Pb+Pb @ 2.76 TeV Axial charge profile b=11.4 fm, Npart=56 Pb+Pb 2.76 TeV, b=11.4 fm, dN5/dxT [a.u.] 0.3 6 uR>uL 0.2 4 uR<uL 0.1 2 0 0 y [fm] -2 -0.1 -4 -0.2 -6 -0.3 -6 -4 -2 0 2 4 6 x [fm] Based on: Chatterjee, Tribedy, Phys. Rev. C 92, Based on: Lappi, Schlichting, Phys. Rev. D 97, 011902 (2015) 034034 (2018) Going beyond cartoon picture: 1) Fluctuations dominate e-by-e physics, 2) B-field & domain size of axial-charge change with √s P.Tribedy, WWND 2020 4 New Theory Guidance : Complexity Of An Event Pb+Pb @ 2.76 TeV Magnetic field b=11.4 fm, N Axial charge profile Pb+Pb 2.76 TeV, b=11.4 fm, dN5/dxT [a.u.] 0.3 6 u 0.2 4 u 0.1 2 0 0 y [fm] -2 -0.1 -4 -0.2 -6 -0.3 -6 -4 -2 0 2 4 6 x [fm] Based on: Chatterjee,
    [Show full text]
  • Search for Isobar Nuclei in Mass Distributions of Heavy Fission Fragments of 235U Nuclei by Thermal Neutrons
    International Conference “Nuclear Science and its Application”, Samarkand, Uzbekistan, September 25-28, 2012 SEARCH FOR ISOBAR NUCLEI IN MASS DISTRIBUTIONS OF HEAVY FISSION FRAGMENTS OF 235U NUCLEI BY THERMAL NEUTRONS Abdullaeva G.A., Koblik Yu.N., Nebesniy A.F., Pikul V.P. Institute of Nuclear Physics, Tashkent, Uzbekistan To search for isobar nuclei in mass distributions of 235U nuclei heavy fission fragments (FF) caused by thermal neutrons we used experimental data from [1]. In [1] experimental data of yields for each value of mass number in FF mass numbers range from A=125 to A=155 a.m.u. depending on effective charge state z* are published. In figure 1 such experimental dependence of FF yields Yi (Ai) =f(z*) and processing of this dependence by Gauss distribution with an error to one σ for each z* is presented. The basic difficulty consisted in correct transition from measured z* to charges of heavy fragments at the moment of nuclear fission. For this purpose we used the modified expression from [2] in the form of: k * α k1 i i ii VzV1zz 0 . Here zi* and zi - the measured effective charge of the i-th ion with mass number Ai and a charge of corresponding fragment, Vi - velocity of ion, Vo - average velocity of electrons interacting with fragment in the target matter and influencing to formation of an effective charge of the ion. Velocity Vi was defined with use of measured value Ek for each fragment. Velocity Vo can 8 changes in limits from Vo = 2.2×10 cm/s - electron velocity in the first orbit of hydrogen atom to 3.6×108 cm/s [2], constants: α =0.45 and k =0.6 are taken as from [2].
    [Show full text]
  • Arxiv:1901.01410V3 [Astro-Ph.HE] 1 Feb 2021 Mental Information Is Available, and One Has to Rely Strongly on Theoretical Predictions for Nuclear Properties
    Origin of the heaviest elements: The rapid neutron-capture process John J. Cowan∗ HLD Department of Physics and Astronomy, University of Oklahoma, 440 W. Brooks St., Norman, OK 73019, USA Christopher Snedeny Department of Astronomy, University of Texas, 2515 Speedway, Austin, TX 78712-1205, USA James E. Lawlerz Physics Department, University of Wisconsin-Madison, 1150 University Avenue, Madison, WI 53706-1390, USA Ani Aprahamianx and Michael Wiescher{ Department of Physics and Joint Institute for Nuclear Astrophysics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556, USA Karlheinz Langanke∗∗ GSI Helmholtzzentrum f¨urSchwerionenforschung, Planckstraße 1, 64291 Darmstadt, Germany and Institut f¨urKernphysik (Theoriezentrum), Fachbereich Physik, Technische Universit¨atDarmstadt, Schlossgartenstraße 2, 64298 Darmstadt, Germany Gabriel Mart´ınez-Pinedoyy GSI Helmholtzzentrum f¨urSchwerionenforschung, Planckstraße 1, 64291 Darmstadt, Germany; Institut f¨urKernphysik (Theoriezentrum), Fachbereich Physik, Technische Universit¨atDarmstadt, Schlossgartenstraße 2, 64298 Darmstadt, Germany; and Helmholtz Forschungsakademie Hessen f¨urFAIR, GSI Helmholtzzentrum f¨urSchwerionenforschung, Planckstraße 1, 64291 Darmstadt, Germany Friedrich-Karl Thielemannzz Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland and GSI Helmholtzzentrum f¨urSchwerionenforschung, Planckstraße 1, 64291 Darmstadt, Germany (Dated: February 2, 2021) The production of about half of the heavy elements found in nature is assigned to a spe- cific astrophysical nucleosynthesis process: the rapid neutron capture process (r-process). Although this idea has been postulated more than six decades ago, the full understand- ing faces two types of uncertainties/open questions: (a) The nucleosynthesis path in the nuclear chart runs close to the neutron-drip line, where presently only limited experi- arXiv:1901.01410v3 [astro-ph.HE] 1 Feb 2021 mental information is available, and one has to rely strongly on theoretical predictions for nuclear properties.
    [Show full text]
  • The Nucleus and Nuclear Instability
    Lecture 2: The nucleus and nuclear instability Nuclei are described using the following nomenclature: A Z Element N Z is the atomic number, the number of protons: this defines the element. A is called the “mass number” A = N + Z. N is the number of neutrons (N = A - Z) Nuclide: A species of nucleus of a given Z and A. Isotope: Nuclides of an element (i.e. same Z) with different N. Isotone: Nuclides having the same N. Isobar: Nuclides having the same A. [A handy way to keep these straight is to note that isotope includes the letter “p” (same proton number), isotone the letter “n” (same neutron number), and isobar the letter “a” (same A).] Example: 206 82 Pb124 is an isotope of 208 82 Pb126 is an isotone of 207 83 Bi124 and an isobar of 206 84 Po122 1 Chart of the Nuclides Image removed. 90 natural elements 109 total elements All elements with Z > 42 are man-made Except for technicium Z=43 Promethium Z = 61 More than 800 nuclides are known (274 are stable) “stable” unable to transform into another configuration without the addition of outside energy. “unstable” = radioactive Images removed. [www2.bnl.gov/ton] 2 Nuclear Structure: Forces in the nucleus Coulomb Force Force between two point charges, q, separated by distance, r (Coulomb’s Law) k0 q1q2 F(N) = 9 2 -2 r 2 k0 = 8.98755 x 10 N m C (Boltzman constant) Potential energy (MeV) of one particle relative to the other k q q PE(MeV)= 0 1 2 r Strong Nuclear Force • Acts over short distances • ~ 10-15 m • can overcome Coulomb repulsion • acts on protons and neutrons Image removed.
    [Show full text]
  • Status of Fission Product Yield Data for Thermal Reactors
    Atomic Energy of Canada Limited STATUS OF FISSION PRODUCT YIELD DATA FOR THERMAL REACTORS by W.H. WALKER Chalk River Nuclear Laboratories Chalk River, Ontario February 1974 AECL-4704, tr - STATUS OF FISSION PRODUCT YIELD DATA FOR THERMAL REACTORS W.H. Walker Review Paper lla for the I.A.E.A. Panel on Fission Product Nuclear Data, held at Bologna, Italy, November 26 - 30, 1973. Chalk River Nuclear Laboratories Chalk River, Ontario February 1974 AECL-4704 STATUS OF FISSION PRODUCT YIELD DATA FOR THERMAL REACTORS by W.H. Walker ABSTRACT Methods of measuring fission product yields are discussed. Measured and evaluated chain yields from thermal neutron fission of 233U, 235U, 239Pu and 21flPu are reviewed and evaluated yields are compared in an appendix. Measured fractional and direct yields of interest in reactor cal- culations are discussed and compiled in an appendix. The few data on cumulative yields from fission by low energy epithermal neutrons are noted and their significance in reactor calculations estimated. Chalk River Nuclear Laboratories Chalk River, Ontario February 1974 AECL-4704 Connaissances actuelles, en matière de rendement des produits de fission, pour les réacteurs thermiques par W.H. Walker Résumé Les méthodes permettant de mesurer le rendement des produits de fission font l'objet de commentaires. Des rendements en chaîne ayant été mesurés et évalués à partir 2 3 3 235 239 de la fission, par neutrons thermiques, de U, U, Pu 241 et Pu sont passés en revue et les rendements évalués font l'objet d'une comparaison dans une annexe. Les rende- ments mesurés, directs ou fractionnels, qui présentent un intérêt pour les calculs de réacteur font l'objet de commen- taires et ils sent compilés dans une annexe.
    [Show full text]
  • The R-Process of Stellar Nucleosynthesis: Astrophysics and Nuclear Physics Achievements and Mysteries
    The r-process of stellar nucleosynthesis: Astrophysics and nuclear physics achievements and mysteries M. Arnould, S. Goriely, and K. Takahashi Institut d'Astronomie et d'Astrophysique, Universit´eLibre de Bruxelles, CP226, B-1050 Brussels, Belgium Abstract The r-process, or the rapid neutron-capture process, of stellar nucleosynthesis is called for to explain the production of the stable (and some long-lived radioac- tive) neutron-rich nuclides heavier than iron that are observed in stars of various metallicities, as well as in the solar system. A very large amount of nuclear information is necessary in order to model the r-process. This concerns the static characteristics of a large variety of light to heavy nuclei between the valley of stability and the vicinity of the neutron-drip line, as well as their beta-decay branches or their reactivity. Fission probabilities of very neutron-rich actinides have also to be known in order to determine the most massive nuclei that have a chance to be involved in the r-process. Even the properties of asymmetric nuclear matter may enter the problem. The enormously challenging experimental and theoretical task imposed by all these requirements is reviewed, and the state-of-the-art development in the field is presented. Nuclear-physics-based and astrophysics-free r-process models of different levels of sophistication have been constructed over the years. We review their merits and their shortcomings. The ultimate goal of r-process studies is clearly to identify realistic sites for the development of the r-process. Here too, the challenge is enormous, and the solution still eludes us.
    [Show full text]
  • Double-Beta Decay of 96Zr and Double-Electron Capture of 156Dy to Excited Final States
    Double-Beta Decay of 96Zr and Double-Electron Capture of 156Dy to Excited Final States by Sean W. Finch Department of Physics Duke University Date: Approved: Werner Tornow, Supervisor Calvin Howell Kate Scholberg Berndt Mueller Albert Chang Dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Physics in the Graduate School of Duke University 2015 Abstract Double-Beta Decay of 96Zr and Double-Electron Capture of 156Dy to Excited Final States by Sean W. Finch Department of Physics Duke University Date: Approved: Werner Tornow, Supervisor Calvin Howell Kate Scholberg Berndt Mueller Albert Chang An abstract of a dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Physics in the Graduate School of Duke University 2015 Copyright c 2015 by Sean W. Finch All rights reserved except the rights granted by the Creative Commons Attribution-Noncommercial License Abstract Two separate experimental searches for second-order weak nuclear decays to excited final states were conducted. Both experiments were carried out at the Kimballton Underground Research Facility to provide shielding from cosmic rays. The first search is for the 2νββ decay of 96Zr to excited final states of the daughter nucleus, 96Mo. As a byproduct of this experiment, the β decay of 96Zr was also investigated. Two coaxial high-purity germanium detectors were used in coincidence to detect γ rays produced by the daughter nucleus as it de-excited to the ground state. After collecting 1.92 years of data with 17.91 g of enriched 96Zr, half-life limits at the level of 1020 yr were produced.
    [Show full text]
  • Nuclear Magic Numbers: New Features Far from Stability
    Nuclear magic numbers: new features far from stability O. Sorlin1, M.-G. Porquet2 1Grand Acc´el´erateur National d’Ions Lours (GANIL), CEA/DSM - CNRS/IN2P3, B.P. 55027, F-14076 Caen Cedex 5, France 2Centre de Spectrom´etrie Nucl´eaire et de Spectrom´etrie de Masse (CSNSM), CNRS/IN2P3 - Universit´eParis-Sud, Bˆat 104-108, F-91405 Orsay, France May 19, 2008 Abstract The main purpose of the present manuscript is to review the structural evolution along the isotonic and isotopic chains around the ”traditional” magic numbers 8, 20, 28, 50, 82 and 126. The exotic regions of the chart of nuclides have been explored during the three last decades. Then the postulate of permanent magic numbers was definitely abandoned and the reason for these structural mutations has been in turn searched for. General trends in the evolution of shell closures are discussed using complementary experimental information, such as the binding energies of the orbits bounding the shell gaps, the trends of the first collective states of the even-even semi-magic nuclei, and the behavior of certain single-nucleon states. Each section is devoted to a particular magic number. It describes the underlying physics of the shell evolution which is not yet fully understood and indicates future experimental and theoretical challenges. The nuclear mean field embodies various facets of the Nucleon- Nucleon interaction, among which the spin-orbit and tensor terms play decisive roles in the arXiv:0805.2561v1 [nucl-ex] 16 May 2008 shell evolutions. The present review intends to provide experimental constraints to be used for the refinement of theoretical models aiming at a good description of the existing atomic nuclei and at more accurate predictions of hitherto unreachable systems.
    [Show full text]
  • Nuclear Mass and Stability
    CHAPTER 3 Nuclear Mass and Stability Contents 3.1. Patterns of nuclear stability 41 3.2. Neutron to proton ratio 43 3.3. Mass defect 45 3.4. Binding energy 47 3.5. Nuclear radius 48 3.6. Semiempirical mass equation 50 3.7. Valley of $-stability 51 3.8. The missing elements: 43Tc and 61Pm 53 3.8.1. Promethium 53 3.8.2. Technetium 54 3.9. Other modes of instability 56 3.10. Exercises 56 3.11. Literature 57 3.1. Patterns of nuclear stability There are approximately 275 different nuclei which have shown no evidence of radioactive decay and, hence, are said to be stable with respect to radioactive decay. When these nuclei are compared for their constituent nucleons, we find that approximately 60% of them have both an even number of protons and an even number of neutrons (even-even nuclei). The remaining 40% are about equally divided between those that have an even number of protons and an odd number of neutrons (even-odd nuclei) and those with an odd number of protons and an even number of neutrons (odd-even nuclei). There are only 5 stable nuclei known which have both 2 6 10 14 an odd number of protons and odd number of neutrons (odd-odd nuclei); 1H, 3Li, 5B, 7N, and 50 23V. It is significant that the first stable odd-odd nuclei are abundant in the very light elements 2 (the low abundance of 1H has a special explanation, see Ch. 17). The last nuclide is found in low isotopic abundance (0.25%) and we cannot be certain that this nuclide is not unstable to radioactive decay with extremely long half-life.
    [Show full text]
  • Stellar Abundances
    Stellar Abundances As probes of stellar nucleosynthesis and chemical evolution I. Basic principles of stellar nucleosynthesis II. Basic ingredients III. Deciphering abundances Francesca Primas ESO KES Lecture – Mar 6, 2017 GCE: some basics The chemical history of the Galaxy is dominated by the nucleosynthesis occurring in many generations of stars • Ini<ally: X=Xi (~0.75) Y=Yi (~0.25) Z=Zi (0.0) Today: X=Xj (~0.73) Y=Yj (~0.25) Z=Zj (0.02) • Elements are made in stars, ejected into the ISM by stellar winds and supernova explosions. • Elements are mixed into the ISM out of which new stars form. Each new stellar generaon is born from gas with higher metallicity: X Y Z yield, IMF, SFR • The cycle repeats itself over billions of years Chemical abundances in the solar system/ vicinity provide the richest informaon. Different ways to sort and group the elements … • By nucleosynthe-c origin and nuclear proper-es • primordial, H-, He-, C-, Ne-, Si-burning, n-captures • stable, long-lived or short-lived radioac<ve Big Bang CR spalla,on H-burning (hydro) H-burning (expl) He-burning C-burning O-burning Ne-burning Expl. Nucleosyn. NSE s-process r-process Origin of atoms in the solar system • Two sources: nucleosynthesis in the BIG BANG and in STARS • The Big Bang made only H and He (and some Li) • All other nuclei are created/produced in stars, by 3 kinds of processes: Nuclear burning (fusion) PP cycles, CNO bi-cycle, He-, C-, O-, Si-burnings … make atoms up to 40Ca (in MS + RG stars) Photodisintegraon rapid nuclear rearrangements, at γ-ray energies
    [Show full text]
  • The Electron Capture in 163Ho Experiment – Echo
    Eur. Phys. J. Special Topics 226, 1623–1694 (2017) © The Author(s) 2017 THE EUROPEAN DOI: 10.1140/epjst/e2017-70071-y PHYSICAL JOURNAL SPECIAL TOPICS Regular Article The electron capture in 163Ho experiment – ECHo L. Gastaldo1,a,K.Blaum2, K. Chrysalidis3,T.DayGoodacre4,A.Domula5, M. Door2,H.Dorrer6,7,8,Ch.E.D¨ullmann6,9,10,K.Eberhardt6,10, S. Eliseev2, C. Enss1, A. Faessler11, P. Filianin2, A. Fleischmann1, D. Fonnesu1, L. Gamer1, R. Haas6, C. Hassel1, D. Hengstler1, J. Jochum12,K.Johnston4, U. Kebschull13, S. Kempf1,T.Kieck3,6,U.K¨oster14,S.Lahiri15, M. Maiti16, F. Mantegazzini1, B. Marsh4, P. Neroutsos13, Yu.N. Novikov2,17,18, P.C.O. Ranitzsch1,b, S. Rothe4, A. Rischka2,A.Saenz19, O. Sander20, F. Schneider3,6, S. Scholl12,R.X.Sch¨ussler2, Ch. Schweiger2, F. Simkovic21,T.Stora4,Z.Sz¨ucs22,A.T¨urler7,8, M. Veinhard4, M. Weber20, M. Wegner1, K. Wendt3, and K. Zuber5 1 Kirchhoff Institute for Physics, Heidelberg University, Heidelberg, Germany 2 Max-Planck Institute for Nuclear Physics, Heidelberg, Germany 3 Institute for Physics, Johannes Gutenberg-University, Mainz, Germany 4 ISOLDE, CERN, Geneve, Switzerland 5 Institute for Nuclear and Particle Physics, TU Dresden, Germany 6 Institute for Nuclear Chemistry, Johannes Gutenberg University, Mainz, Germany 7 Laboratory of Radiochemistry and Environmental Chemistry, Department Biology and Chemistry, Paul Scherrer Institute, Villigen PSI, Switzerland 8 Laboratory of Radiochemistry and Environmental Chemistry, Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, Bern,
    [Show full text]
  • Arxiv:1908.10231V2 [Nucl-Th] 25 Oct 2019 Could Disentangle the Background from the Signal
    Influence of the neutron-skin effect on nuclear isobar collisions at RHIC Jan Hammelmann,1, 2, ∗ Alba Soto-Ontoso,3, y Massimiliano Alvioli,4, z Hannah Elfner,5, 1, 2, x and Mark Strikman6, { 1Goethe-Universit¨atFrankfurt, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main, Germany. 2Frankfurt Institute for Advanced Studies, Ruth-Moufang-Strasse 1, 60438 Frankfurt am Main, Germany. 3Physics Department, Brookhaven National Laboratory, Upton, NY 11973, USA. 4Consiglio Nazionale delle Ricerche, Istituto di Ricerca per la Protezione Idrogeologica, via Madonna Alta 126, I-06128 Perugia, Italy. 5GSI Helmholtzzentrum f¨urSchwerionenforschung GmbH, Planckstr. 1, 64291 Darmstadt, Germany. 6Pennsylvania State University, University Park, PA 16802, USA. The unambiguous observation of a Chiral Magnetic Effect (CME)-driven charge separation is 96 96 96 96 pthe core aim of the isobar program at RHIC consisting of 40Zr+40Zr and 44Ru+44Ru collisions at sNN = 200 GeV. We quantify the role of the spatial distributions of the nucleons in the isobars on both eccentricity and magnetic field strength within a relativistic hadronic transport approach (SMASH, Simulating Many Accelerated Strongly-interacting Hadrons). In particular, we introduce isospin-dependent nucleon-nucleon spatial correlations in the geometric description of both nuclei, 96 96 deformation for 44Ru and the so-called neutron skin effect for the neutron-rich isobar i.e. 40Zr. The 96 96 main result of this study is a reduction of the magnetic field strength difference between 44Ru+44Ru 96 96 and 40Zr+40Zr by a factor of 2, from 10% to 5% in peripheral collisions when the neutron-skin effect is included.
    [Show full text]