Found the Tetraneutron
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Four Neutrons Together Momentarily
RESEARCH NEWS & VIEWS because developmental studies have shown ago or before8, remain unclear. Perhaps even 2. Johnson, R. G. & Richardson, E. S. Fieldiana Geol. that lampreys and hagfishes are more closely weirder fossil vertebrates remain to be dug up. ■ 12, 119–149 (1969). 3. McCoy, V. E. et al. Nature 532, 496–499 (2016). related to each other than was previously 4. Clements, T. et al. Nature 532, 500–503 (2016). imagined7, it could also represent an animal close Shigeru Kuratani and Tatsuya Hirasawa are 5. Richardson, E. S. Science 151, 75–76 (1966). to the origin of cyclostomes before the lamprey– in the Evolutionary Morphology Laboratory, 6. Janvier, P. Early Vertebrates (Oxford Univ. Press, 1996). hagfish divergence. That would mean that early RIKEN, Kobe, Hyogo 650-0047, Japan. 7. Oisi, Y., Ota, K. G., Fujimoto, S. & Kuratani, S. Nature cyclostomes exhibited a tremendous range of e-mails: [email protected]; 493, 175–180 (2013). morphological variety. Indeed, the details of the [email protected] 8. Kuraku, S. & Kuratani, S. Zool. Sci. 23, 1053–1064 (2006). early divergence of cyclostomes, which has been 1. Traquair, R. H. Ann. Mag. Nat. Hist. 6th ser. 6, inferred to have occurred 390 million years 479–486 (1890). This article was published online on 13 April 2016. NUCLEAR PHYSICS can be easily transformed in the interaction with 4He. The authors observed that the 8He projectile exchanges two units of charge with the 4He Four neutrons together target and becomes a beryllium-8 nucleus (8Be, four protons and four neutrons), the energy of which was measured with high precision. -
Nuclear Structure at the Drip Lines
; ~' '; i hltematiom1! Nuclear Physics Conference Wiesbaden, Germany, July 26 • August 1, 1992 (To be published in Nucl.Phys. A) Nuclear structure at the drip lines P.G. Hansen Institute of Physics and Astronomy, University of Aarhus DK-8000 Aarhus C Abstract The drip-line nuclei under certain circumstances form a neutron or proton halo with a mass distribution that extends far outside the nuclear core. Examples are given of how this structure manifests itself through nuclear reaction cross-sections and angular distributions. A comparison with related phenomena in atoms and molecules is given. 1. THE LIMITS OF NUCLEAR STABILITY The isobaric lines across the nuclear chart are terminated by instability towards the emission of nucleons. The two limits, to the north-west and south-east, correspond roughly to zero binding for protons and neutrons and are commonly referred to as the drip lines. During the last years there has been a rapid development in our ability to investigate nuclei close to the drip lines thanks to a variety of techniques involving radioactive beams from isotope separators and recoil spectrometers. The proceedings [1] of a recent conference and also the review [2] give a good overview of activities in this field, which is right now subject to an intense interest. Many new results were presented at the 1992 Bernkastel-Kues Conference [3]. In this presentation I shall on the neutron drip line where novel phenomena have appeared, but even to this sub-sub specialty I cannot do full justice, especially with respect to the very many interesting theoretical papers. 1.1 The proton drip line Owing to the Coulomb repulsion it is not possible to have nuclei with a very large proton excess and for the lighter elements the proton drip line lies rather close to the N=Z line. -
1 Arguments for Detecting Octaneutrons in Cluster Decay of Cf
Arguments for Detecting Octaneutrons in Cluster Decay of 252Cf Nuclei G.N. Dudkin, A.A. Garapatskii and V.N. Padalko Tomsk Polytechnic University, 634050 Tomsk, Russia E-mail: [email protected] Abstract A new method of searching for neutron clusters (multineutrons) composed of neutrons bound by nuclear forces has been introduced and implemented. The method is based on the search for daughter nuclei that emerge at the nuclei cluster decay of 252Cf to neutron clusters. The effect of long-time build-up of daughter nuclei with a high atomic number and long half-life was utilized. As a result, the cluster decay of 252Cf to a daughter nucleus 232U (half- life of 232 T1/2= 68.9·years) was discovered. It is assumed that the emergence of U nuclei is attributed to emission of neutron clusters consisting of eight neutrons - octaneutrons. The emission probability of octaneutrons against α-decay 252 -6 probability of Cf is defined equal to λC/λα = 1.74·10 . PACS numbers:23.70.+j 21.10.Gv 23.20.Lv 27.90.+b Keywords: cluster decay of nucleus; neutron cluster; daughter nucleus; high pure germanium detector; spectrum of γ – quanta; emission probability of octaneutron 1. Introduction The issue of stable nuclei (clusters) existence consisting of only neutrons has been the focus of experimental and theoretical research for 50 years. The detection of neutron nuclei would mean a discovery of a new type of nuclear matter bound with nuclear forces of xn neutrons, where x is a number of bound neutrons. Such a discovery would have a great significance for all areas of nuclear physics as well as for astrophysics (neutron stars, r-process). -
185 Can Four Neutrons Form a Stable Nucleus? Ahmed Alharbi 1, 2 1
Can Four Neutrons Form a Stable Nucleus? Ahmed Alharbi 1, 2 1. Department of Physics, Qassim University, Qassim 51452, Kingdom of Saudi Arabia 2. Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8SU, United Kingdom [email protected] Abstract: The existence of a stable 4-neutron (4n) nucleus has been investigated theoretically and experimentally for more than five decades. Several experimental approaches were adopted in the previous century with the aim of observing 4n nuclei yielded negative results. However, in this century, the GANEL experiment has supported the existence of a tetraneutron (4n) nucleus as a long-lived nucleus by detecting 6 events of 4n nuclei. This experimental result, however, has not been confirmed by subsequent studies. Moreover, in the most recent experiment RIKEN 2016, 4 events of a tetraneutron system were obtained in a resonant state and supported by a subsequent theoretical calculation. However, both findings from GANEL and RIKEN experiments indicate that 4n nuclei are unstable, as they decayed after a short time. The detection of such nuclei is significant to investigate properties of the nuclear forces needed to fuse the 4n together as chargeless nuclei. Although the existence of a stable tetraneutron nucleus has not been confirmed yet, it is still an open and fascinating question. Future studies aim to be built on the previous experiments by maximizing the beam energy of a projectile as well as optimizing a thick target. [Ahmed Alharbi. Can Four Neutrons Form a Stable Nucleus? Nat Sci 2020;18(1):185-189]. ISSN 1545-0740 (print); ISSN 2375-7167 (online). -
2017 Volume 13 Issues
Issues 1-4 2017 Volume 13 The Journal on Advanced Studies in Theoretical and Experimental Physics, including Related Themes from Mathematics PROGRESS IN PHYSICS “All scientists shall have the right to present their scientific research results, in whole or in part, at relevant scientific conferences, and to publish the same in printed scientific journals, electronic archives, and any other media.” — Declaration of Academic Freedom, Article 8 ISSN 1555-5534 The Journal on Advanced Studies in Theoretical and Experimental Physics, including Related Themes from Mathematics PROGRESS IN PHYSICS A quarterly issue scientific journal, registered with the Library of Congress (DC, USA). This journal is peer reviewed and included in the abstracting and indexing coverage of: Mathematical Reviews and MathSciNet (AMS, USA), DOAJ of Lund University (Sweden), Scientific Commons of the University of St. Gallen (Switzerland), Open-J-Gate (India), Referativnyi Zhurnal VINITI (Russia), etc. Electronic version of this journal: January 2017 Vol. 13, Issue 1 http://www.ptep-online.com Advisory Board Dmitri Rabounski, CONTENTS Editor-in-Chief, Founder Florentin Smarandache, Daywitt W.C. An Explanation of De Broglie Matter Waves in Terms of the Electron Associate Editor, Founder CouplingtotheVacuumState........................... .......................3 Larissa Borissova, Associate Editor, Founder Silva N.P. BeyondtheHubble’sLaw............................... .................5 Belyakov A.V. AreQuazarsWhiteHoles?.............................. ..............7 Editorial Board Levin B.M. Pierre Millette Atom of Long-Range Action Instead of Counter-Productive Tachyon [email protected] Phenomenology. Decisive Experiment of the New (Additional) Phenomenology Andreas Ries OutsideoftheLightCone.............................. ......................11 [email protected] Levin B.M. Half-Century History of the Project of New (Additional) G~/ck-Physics . 18 Gunn Quznetsov Belmonte C., Vanden Berghe F., Panajotov K., Durt T.