Energy Technology Data Exchange (ETDEWEB)
Quaglioni, S; Navratil, P; Roth, R
2009-12-15
The exact treatment of nuclei starting from the constituent nucleons and the fundamental interactions among them has been a long-standing goal in nuclear physics. Above all nuclear scattering and reactions, which require the solution of the many-body quantum-mechanical problem in the continuum, represent an extraordinary theoretical as well as computational challenge for ab initio approaches.We present a new ab initio many-body approach which derives from the combination of the ab initio no-core shell model with the resonating-group method [4]. By complementing a microscopic cluster technique with the use of realistic interactions, and a microscopic and consistent description of the nucleon clusters, this approach is capable of describing simultaneously both bound and scattering states in light nuclei. We will discuss applications to neutron and proton scattering on sand light p-shell nuclei using realistic nucleon-nucleon potentials, and outline the progress toward the treatment of more complex reactions.
Nuclear astrophysics of light nuclei
DEFF Research Database (Denmark)
Fynbo, Hans Otto Uldall
2013-01-01
A review of nuclear astrophysics of light nuclei using radioactive beams or techniques developed for radioactive beams is given. We discuss Big Bang nucleosynthesis, with special focus on the lithium problem, aspects of neutrino-physics, helium-burning and finally selected examples of studies...
Continuum spectroscopy of light nuclei
Directory of Open Access Journals (Sweden)
Charity R. J.
2016-01-01
Full Text Available Resonance spectroscopy of light nuclei is discussed with emphasis on the invariant-mass measurements performed with the HiRA detector. For three-body exit channels, we consider the exact conditions necessary such that the decay can be described as either sequential or prompt. However experimentally, we find some cases where the decay is intermediate between these two limits. Finally, two-proton decay from isobaric analog states is discussed.
Quantum Monte Carlo Calculations of Light Nuclei
Pieper, Steven C
2007-01-01
During the last 15 years, there has been much progress in defining the nuclear Hamiltonian and applying quantum Monte Carlo methods to the calculation of light nuclei. I describe both aspects of this work and some recent results.
Studies of exotic light nuclei
Energy Technology Data Exchange (ETDEWEB)
Cerny, J.
1976-05-01
For neutron-deficient nuclei, extension of the T/sub z/ = --3/2 series of strong beta-delayed proton precursors to /sup 61/Ge is discussed. For neutron-excess nuclei, heavy-ion induced, multi-nucleon transfer reaction studies of masses and energy levels of 2sld shell nuclei with T/sub z/ greater than or equal to 5/2 are covered. In addition, preliminary attempts to employ the (/sup 7/Li,/sup 2/He) reaction for the latter studies are shown; a new detection system capable of observing unbound final states as reaction products is demonstrated via investigations of the (..cap alpha..,/sup 2/He) reaction.
Geometric symmetries in light nuclei
Bijker, Roelof
2016-01-01
The algebraic cluster model is is applied to study cluster states in the nuclei 12C and 16O. The observed level sequences can be understood in terms of the underlying discrete symmetry that characterizes the geometrical configuration of the alpha-particles, i.e. an equilateral triangle for 12C, and a regular tetrahedron for 16O. The structure of rotational bands provides a fingerprint of the underlying geometrical configuration of alpha-particles.
Monte Carlo approaches to light nuclei
Energy Technology Data Exchange (ETDEWEB)
Carlson, J.
1990-01-01
Significant progress has been made recently in the application of Monte Carlo methods to the study of light nuclei. We review new Green's function Monte Carlo results for the alpha particle, Variational Monte Carlo studies of {sup 16}O, and methods for low-energy scattering and transitions. Through these calculations, a coherent picture of the structure and electromagnetic properties of light nuclei has arisen. In particular, we examine the effect of the three-nucleon interaction and the importance of exchange currents in a variety of experimentally measured properties, including form factors and capture cross sections. 29 refs., 7 figs.
Nucleon localization in light and heavy nuclei
Zhang, C L; Nazarewicz, W
2016-01-01
An electron localization measure was originally introduced to characterize chemical bond structures in molecules. Recently, a nucleon localization based on Hartree-Fock densities has been introduced to investigate $\\alpha$-cluster structures in light nuclei. Compared to the local nucleonic densities, the nucleon localization function has been shown to be an excellent indicator of shell effects and cluster correlations. Using the spatial nucleon localization measure, we investigate the cluster structures in deformed light nuclei and study the emergence of fragments in fissioning heavy nuclei. To illustrate basic concepts of nucleon localization, we employ the deformed harmonic oscillator model. Realistic calculations are carried out using self-consistent nuclear density functional theory with quantified energy density functionals optimized for fission studies. We study particle densities and spatial nucleon localization distributions for deformed cluster configurations of $^{8}$Be and $^{20}$Ne, and also along...
Light nuclei from chiral EFT interactions
Navrátil, P.; Gueorguiev, V. G.; Vary, J. P.; Ormand, W. E.; Nogga, A.; Quaglioni, S.
2008-12-01
Recent developments in nuclear theory allow us to make a connection between quantum chromodynamics (QCD) and low-energy nuclear physics. First, chiral effective field theory (χEFT) provides a natural hierarchy to define two-nucleon ( NN), three-nucleon ( NNN), and even four-nucleon interactions. Second, ab-initio methods have been developed capable to test these interactions for light nuclei. In this contribution, we discuss ab-initio no-core shell-model (NCSM) calculations for s-shell and p-shell nuclei with NN and NNN interactions derived within χEFT.
Precision lifetime measurements in light exotic nuclei
McCutchan, Elizabeth
2017-01-01
A new generation of ab-initio calculations, based on realistic two- and three-body forces have had a profound impact on our understanding of nuclei. They have shed light on topics such as the origin of effective forces (like spin-orbit and tensor interactions) and the mechanisms behind cluster and pairing correlations. New precise data are required to both better parameterize the three body forces and to improve numerical methods. A sensitive probe of the structure of light nuclei comes from their electromagnetic transition rates. A refined Doppler Shift Attenuation Method (DSAM) will be outlined which is used to precisely measure lifetimes in light nuclei and helps to reduce and quantity systematic uncertainties in the measurement. Using this careful DSAM, we have made a series of precise measurements of electromagnetic transition strengths in Li isotopes, A =10 nuclei, and the exotic halo nucleus, 12Be. Various phenomena, such as alpha clustering and meson-exchange currents, can be investigated in these seemingly simple systems, while the collection of data spanning stable to neutron-rich, allows us to probe the influence of additional valence neutrons. This talk will report on what has been learned, and the challenges that lie in the future, both in experiment and theory, as we push to describing and measuring even more exotic systems. Work supported by the Office of Nuclear Physics, Office of Science of the U.S. Department of Energy under contract No. DE-AC02-98CH10886.
Light nuclei production in heavy ion collisions
Khan, K H; Wazir, Z; Khan, E U; Haseeb, Mahnaz Q; Ajaz, M
2009-01-01
Light nuclei production as a result of nuclear coalescence effect can give some signals on final state of Quark Gluon Plasma formation. We are studying the behavior of nuclear modification factor as a function of different variables using the simulated data coming from the FASTMC generator. This data is necessary to extract information on coalescence mechanism from experimental data on high energy nuclear-nuclear interactions.
Probing Chiral Interactions in Light Nuclei
Energy Technology Data Exchange (ETDEWEB)
Nogga, A; Barrett, B R; Meissner, U; Witala, H; Epelbaum, E; Kamada, H; Navratil, P; Glockle, W; Vary, J P
2004-01-08
Chiral two- and three-nucleon interactions are studied in a few-nucleon systems. We investigate the cut-off dependence and convergence with respect to the chiral expansion. It is pointed out that the spectra of light nuclei are sensitive to the three-nucleon force structure. As an example, we present calculations of the 1{sup +} and 3{sup +} states of {sup 6}Li using the no-core shell model approach. The results show contributions of the next-to-next-to-leading order terms to the spectra, which are not correlated to the three-nucleon binding energy prediction.
Few-body resonances in light nuclei
Csoto, A
2000-01-01
We have localized several few-body resonances in light nuclei, using methods which can properly handle two- or three-body resonant states. Among other results, we predict the existence of a three-neutron resonance, small spin-orbit splittings between the low-lying states in He-5 and Li-5, the nonexistence of the soft dipole resonance in He-6, new 1+ states in Li-8 and B-8, and the presence of a nonlinear amplification phenomenon in the 0+_2 state of C-12.
Clusters in neutron-rich light nuclei
Directory of Open Access Journals (Sweden)
Jelavić Malenica D.
2016-01-01
Full Text Available Due to their high selectivity, transfer and sequential decay reactions are powerful tools for studies of both single particle (nucleon and cluster states in light nuclei. Their use is particularly simple for investigations of α-particle clustering (because α-particle has Jπ=0+, which simplifies spin and parity assignments to observed cluster states, but they are also easily applicable to other types of clustering. Recent results on clustering in neutron-rich isotopes of beryllium, boron and carbon obtained measuring the 10B+10B reactions (at 50 and 72 MeV are presented. The highly efficient and segmented detector systems used, built from 4 Double Sided Silicon Strip Detectors (DSSSD allowed detection of double and multiple coincidences and, in that way, studies of states populated in transfer reactions, as well as their sequential decay.
Origin of light nuclei in near earth orbit
Derome, L
2001-01-01
The possible sources of light nuclei populations observed recently below the geomagnetic cutoff by the AMS experiment are discussed in terms of nuclear processes: fragmentation of the incoming flux of cosmic helium on atmospheric nuclei, and nuclear coalescence from proton and helium induced reactions. Results of simulations for deuterium, tritium, helium 3 and 4, are presented.
New aspects of the neutron capture in light nuclei
Energy Technology Data Exchange (ETDEWEB)
Mengoni, A. [Institute of Physical and Chemical Research, Wako, Saitama (Japan)
1997-03-01
Several neutron capture cross sections of light nuclei (A {<=} 40) for neutron energies up to the MeV region have been recently calculated. Examples are (target nuclei): {sup 12}C, {sup 13}C, {sup 16}O and {sup 10}Be. The results of these calculations will be shown together with a comparison with the most recent experimental data. In the case of n + {sup 10}Be case, the cross section of the inverse process (Coulomb dissociation of {sup 11}Be) is considered and compared with the measurement. A discussion on the relevant nuclear structure information required for the evaluation of nuclear data of light nuclei is given. (author)
Green's function calculations of light nuclei
Sun, ZhongHao; Wu, Qiang; Xu, FuRong
2016-09-01
The influence of short-range correlations in nuclei was investigated with realistic nuclear force. The nucleon-nucleon interaction was renormalized with V lowk technique and applied to the Green's function calculations. The Dyson equation was reformulated with algebraic diagrammatic constructions. We also analyzed the binding energy of 4He, calculated with chiral potential and CD-Bonn potential. The properties of Green's function with realistic nuclear forces are also discussed.
AMS with light nuclei at small accelerators
Stan-Sion, C.; Enachescu, M.
2017-06-01
AMS applications with lighter nuclei are presented. It will be shown how Carbon-14, Boron-10, Beryllium-10, and Tritium-3 can be used to provide valuable information in forensic science, environmental physics, nuclear pollution, in material science and for diagnose of the plasma confinement in fusion reactors. Small accelerators are reliable, efficient and possess the highest ion beam transmissions that confer high precision in measurements.
Review of the electric dipole moment of light nuclei
Yamanaka, Nodoka
2016-01-01
In this review, we summarize the theoretical development on the electric dipole moment of light nuclei. We first describe the nucleon level CP violation and its parametrization. We then present the results of calculations of the EDM of light nuclei in the ab initio approach and in the cluster model. The analysis of the effect of several models beyond standard model is presented, together with the prospects for its discovery. The advantage of the electric dipole moment of light nuclei is focused in the point of view of the many-body physics. The evaluations of the nuclear electric dipole moment generated by the $\\theta$-term and by the CP phase of the Cabibbo-Kobayashi-Maskawa matrix are also reviewed.
MCNP6 fragmentation of light nuclei at intermediate energies
Mashnik, Stepan G
2014-01-01
Fragmentation reactions induced on light target nuclei by protons and light nuclei of energies around 1 GeV/nucleon and below are studied with the latest Los Alamos Monte Carlo transport code MCNP6 and with its cascade-exciton model (CEM) and Los Alamos version of the quark-gluon string model (LAQGSM) event generators, version 03.03, used as stand-alone codes. Such reactions are involved in different applications, like cosmic-ray-induced single event upsets (SEU's), radiation protection, and cancer therapy with proton and ion beams, among others; therefore, it is important that MCNP6 simulates them as well as possible. CEM and LAQGSM assume that intermediate-energy fragmentation reactions on light nuclei occur generally in two stages. The first stage is the intranuclear cascade (INC), followed by the second, Fermi breakup disintegration of light excited residual nuclei produced after INC. Both CEM and LAQGSM account also for coalescence of light fragments (complex particles) up to He4 from energetic nucleons ...
Haloes and clustering in light, neutron-rich nuclei
Energy Technology Data Exchange (ETDEWEB)
Orr, N.A
2001-10-01
Clustering is a relatively widespread phenomenon which takes on many guises across the nuclear landscape. Selected topics concerning the study of halo systems and clustering in light, neutron-rich nuclei are discussed here through illustrative examples taken from the Be isotopic chain. (author)
Rare βp decays in light nuclei
DEFF Research Database (Denmark)
Borge, M.J.G.; Fraile, L.M.; Fynbo, Hans Otto Uldall
2013-01-01
Beta-delayed proton emission may occur at very low rates in the decays of the light nuclei 11Be and 8B. This paper explores the potential physical significance of such decays, estimates their rates and reports on first attempts to detect them: an experiment at ISOLDE/CERN gives a branching ratio...
On the Formation Mechanism of the Atomcule of Light Nuclei
Dineykhan, M D; Sakhyev, S K
2002-01-01
In the framework of the oscillator representation method the interaction potential between the antiproton and the nucleus is analytically derived. This potential is antisymmetrical with respect to the charge and masses of the constituent particles. It is shown that the antisymmetry of the potential determines the stability of the atomcule of light nuclei.
Electric dipole moments of light nuclei from χEFT
Higa, Renato
2013-03-01
I present recent calculations of EDMs of light nuclei using chiral effective field theory techniques. At leading-order, we argue that they can be expressed in terms of six CP-violating low-energy constants. With our expressions, eventual non-zero measurements of EDMs of deuteron, helion, and triton can be combined to disentangle the different sources of CP-violation.
Electric dipole moments of light nuclei
Mereghetti, Emanuele
2017-01-01
Electric dipole moments (EDMs) are extremely sensitive probes of physics beyond the Standard Model (SM). A vibrant experimental program is in place, with the goal to improve the existing neutron EDM bound by one/two orders of magnitude, and to test new ideas for the measurement of EDMs of light ions, such as deuteron and helium, at a comparable level. The success of this program, and its implications for physics beyond the SM, relies on the precise calculation of the EDMs in terms of the couplings of CP-violating operators. In light of the non-perturbative nature both of QCD at low energy and of the nuclear interactions, these calculations have proven difficult, and are affected by large theoretical uncertainties. In this talk I will review the progress that in recent years has been achieved on different aspects of the calculation of hadronic and nuclear EDMs. In particular, I will discuss how the interplay between lattice QCD and Chiral Effective Field Theory (EFT) has allowed to reduce a set of hadronic uncertainties. Finally, I will discuss how the measurements of th EDMs of one, two and three nucleon systems can be used to discriminate between various possible mechanisms of time-reversal violation at high energy.
Precision measurement of the mass difference between light nuclei and anti-nuclei
Adam, Jaroslav; Aggarwal, Madan Mohan; Aglieri Rinella, Gianluca; Agnello, Michelangelo; Agrawal, Neelima; Ahammed, Zubayer; Ahmed, Ijaz; Ahn, Sang Un; Aimo, Ilaria; Aiola, Salvatore; Ajaz, Muhammad; Akindinov, Alexander; Alam, Sk Noor; Aleksandrov, Dmitry; Alessandro, Bruno; Alexandre, Didier; Alfaro Molina, Jose Ruben; Alici, Andrea; Alkin, Anton; Alme, Johan; Alt, Torsten; Altinpinar, Sedat; Altsybeev, Igor; Alves Garcia Prado, Caio; Andrei, Cristian; Andronic, Anton; Anguelov, Venelin; Anielski, Jonas; Anticic, Tome; Antinori, Federico; Antonioli, Pietro; Aphecetche, Laurent Bernard; Appelshaeuser, Harald; Arcelli, Silvia; Armesto Perez, Nestor; Arnaldi, Roberta; Aronsson, Tomas; Arsene, Ionut Cristian; Arslandok, Mesut; Augustinus, Andre; Averbeck, Ralf Peter; Azmi, Mohd Danish; Bach, Matthias Jakob; Badala, Angela; Baek, Yong Wook; Bagnasco, Stefano; Bailhache, Raphaelle Marie; Bala, Renu; Baldisseri, Alberto; Ball, Markus; Baltasar Dos Santos Pedrosa, Fernando; Baral, Rama Chandra; Barbano, Anastasia Maria; Barbera, Roberto; Barile, Francesco; Barnafoldi, Gergely Gabor; Barnby, Lee Stuart; Ramillien Barret, Valerie; Bartalini, Paolo; Bartke, Jerzy Gustaw; Bartsch, Esther; Basile, Maurizio; Bastid, Nicole; Basu, Sumit; Bathen, Bastian; Batigne, Guillaume; Batista Camejo, Arianna; Batyunya, Boris; Batzing, Paul Christoph; Bearden, Ian Gardner; Beck, Hans; Bedda, Cristina; Behera, Nirbhay Kumar; Belikov, Iouri; Bellini, Francesca; Bello Martinez, Hector; Bellwied, Rene; Belmont Iii, Ronald John; Belmont Moreno, Ernesto; Belyaev, Vladimir; Bencedi, Gyula; Beole, Stefania; Berceanu, Ionela; Bercuci, Alexandru; Berdnikov, Yaroslav; Berenyi, Daniel; Bertens, Redmer Alexander; Berzano, Dario; Betev, Latchezar; Bhasin, Anju; Bhat, Inayat Rasool; Bhati, Ashok Kumar; Bhattacharjee, Buddhadeb; Bhom, Jihyun; Bianchi, Livio; Bianchi, Nicola; Bianchin, Chiara; Bielcik, Jaroslav; Bielcikova, Jana; Bilandzic, Ante; Biswas, Saikat; Bjelogrlic, Sandro; Blanco, Fernando; Blau, Dmitry; Blume, Christoph; Bock, Friederike; Bogdanov, Alexey; Boggild, Hans; Boldizsar, Laszlo; Bombara, Marek; Book, Julian Heinz; Borel, Herve; Borissov, Alexander; Borri, Marcello; Bossu, Francesco; Botje, Michiel; Botta, Elena; Boettger, Stefan; Braun-Munzinger, Peter; Bregant, Marco; Breitner, Timo Gunther; Broker, Theo Alexander; Browning, Tyler Allen; Broz, Michal; Brucken, Erik Jens; Bruna, Elena; Bruno, Giuseppe Eugenio; Budnikov, Dmitry; Buesching, Henner; Bufalino, Stefania; Buncic, Predrag; Busch, Oliver; Buthelezi, Edith Zinhle; Buxton, Jesse Thomas; Caffarri, Davide; Cai, Xu; Caines, Helen Louise; Calero Diaz, Liliet; Caliva, Alberto; Calvo Villar, Ernesto; Camerini, Paolo; Carena, Francesco; Carena, Wisla; Castillo Castellanos, Javier Ernesto; Castro, Andrew John; Casula, Ester Anna Rita; Cavicchioli, Costanza; Ceballos Sanchez, Cesar; Cepila, Jan; Cerello, Piergiorgio; Chang, Beomsu; Chapeland, Sylvain; Chartier, Marielle; Charvet, Jean-Luc Fernand; Chattopadhyay, Subhasis; Chattopadhyay, Sukalyan; Chelnokov, Volodymyr; Cherney, Michael Gerard; Cheshkov, Cvetan Valeriev; Cheynis, Brigitte; Chibante Barroso, Vasco Miguel; Dobrigkeit Chinellato, David; Chochula, Peter; Choi, Kyungeon; Chojnacki, Marek; Choudhury, Subikash; Christakoglou, Panagiotis; Christensen, Christian Holm; Christiansen, Peter; Chujo, Tatsuya; Chung, Suh-Urk; Cicalo, Corrado; Cifarelli, Luisa; Cindolo, Federico; Cleymans, Jean Willy Andre; Colamaria, Fabio Filippo; Colella, Domenico; Collu, Alberto; Colocci, Manuel; Conesa Balbastre, Gustavo; Conesa Del Valle, Zaida; Connors, Megan Elizabeth; Contreras Nuno, Jesus Guillermo; Cormier, Thomas Michael; Corrales Morales, Yasser; Cortes Maldonado, Ismael; Cortese, Pietro; Cosentino, Mauro Rogerio; Costa, Filippo; Crochet, Philippe; Cruz Albino, Rigoberto; Cuautle Flores, Eleazar; Cunqueiro Mendez, Leticia; Dahms, Torsten; Dainese, Andrea; Danu, Andrea; Das, Debasish; Das, Indranil; Das, Supriya; Dash, Ajay Kumar; Dash, Sadhana; De, Sudipan; De Caro, Annalisa; De Cataldo, Giacinto; De Cuveland, Jan; De Falco, Alessandro; De Gruttola, Daniele; De Marco, Nora; De Pasquale, Salvatore; Deisting, Alexander; Deloff, Andrzej; Denes, Ervin Sandor; D'Erasmo, Ginevra; Di Bari, Domenico; Di Mauro, Antonio; Di Nezza, Pasquale; Diaz Corchero, Miguel Angel; Dietel, Thomas; Dillenseger, Pascal; Divia, Roberto; Djuvsland, Oeystein; Dobrin, Alexandru Florin; Dobrowolski, Tadeusz Antoni; Domenicis Gimenez, Diogenes; Donigus, Benjamin; Dordic, Olja; Dubey, Anand Kumar; Dubla, Andrea; Ducroux, Laurent; Dupieux, Pascal; Ehlers Iii, Raymond James; Elia, Domenico; Engel, Heiko; Erazmus, Barbara Ewa; Erhardt, Filip; Eschweiler, Dominic; Espagnon, Bruno; Estienne, Magali Danielle; Esumi, Shinichi; Evans, David; Evdokimov, Sergey; Eyyubova, Gyulnara; Fabbietti, Laura; Fabris, Daniela; Faivre, Julien; Fantoni, Alessandra; Fasel, Markus; Feldkamp, Linus; Felea, Daniel; Feliciello, Alessandro; Feofilov, Grigorii; Ferencei, Jozef; Fernandez Tellez, Arturo; Gonzalez Ferreiro, Elena; Ferretti, Alessandro; Festanti, Andrea; Figiel, Jan; Araujo Silva Figueredo, Marcel; Filchagin, Sergey; Finogeev, Dmitry; Fionda, Fiorella; Fiore, Enrichetta Maria; Fleck, Martin Gabriel; Floris, Michele; Foertsch, Siegfried Valentin; Foka, Panagiota; Fokin, Sergey; Fragiacomo, Enrico; Francescon, Andrea; Frankenfeld, Ulrich Michael; Fuchs, Ulrich; Furget, Christophe; Furs, Artur; Fusco Girard, Mario; Gaardhoeje, Jens Joergen; Gagliardi, Martino; Gago Medina, Alberto Martin; Gallio, Mauro; Gangadharan, Dhevan Raja; Ganoti, Paraskevi; Gao, Chaosong; Garabatos Cuadrado, Jose; Garcia-Solis, Edmundo Javier; Gargiulo, Corrado; Gasik, Piotr Jan; Germain, Marie; Gheata, Andrei George; Gheata, Mihaela; Ghosh, Premomoy; Ghosh, Sanjay Kumar; Gianotti, Paola; Giubellino, Paolo; Giubilato, Piero; Gladysz-Dziadus, Ewa; Glassel, Peter; Gomez Ramirez, Andres; Gonzalez Zamora, Pedro; Gorbunov, Sergey; Gorlich, Lidia Maria; Gotovac, Sven; Grabski, Varlen; Graczykowski, Lukasz Kamil; Grelli, Alessandro; Grigoras, Alina Gabriela; Grigoras, Costin; Grigoryev, Vladislav; Grigoryan, Ara; Grigoryan, Smbat; Grynyov, Borys; Grion, Nevio; Grosse-Oetringhaus, Jan Fiete; Grossiord, Jean-Yves; Grosso, Raffaele; Guber, Fedor; Guernane, Rachid; Guerzoni, Barbara; Gulbrandsen, Kristjan Herlache; Gulkanyan, Hrant; Gunji, Taku; Gupta, Anik; Gupta, Ramni; Haake, Rudiger; Haaland, Oystein Senneset; Hadjidakis, Cynthia Marie; Haiduc, Maria; Hamagaki, Hideki; Hamar, Gergoe; Hanratty, Luke David; Hansen, Alexander; Harris, John William; Hartmann, Helvi; Harton, Austin Vincent; Hatzifotiadou, Despina; Hayashi, Shinichi; Heckel, Stefan Thomas; Heide, Markus Ansgar; Helstrup, Haavard; Herghelegiu, Andrei Ionut; Herrera Corral, Gerardo Antonio; Hess, Benjamin Andreas; Hetland, Kristin Fanebust; Hilden, Timo Eero; Hillemanns, Hartmut; Hippolyte, Boris; Hristov, Peter Zahariev; Huang, Meidana; Humanic, Thomas; Hussain, Nur; Hussain, Tahir; Hutter, Dirk; Hwang, Dae Sung; Ilkaev, Radiy; Ilkiv, Iryna; Inaba, Motoi; Ionita, Costin; Ippolitov, Mikhail; Irfan, Muhammad; Ivanov, Marian; Ivanov, Vladimir; Izucheev, Vladimir; Jacobs, Peter Martin; Jahnke, Cristiane; Jang, Haeng Jin; Janik, Malgorzata Anna; Pahula Hewage, Sandun; Jena, Chitrasen; Jena, Satyajit; Jimenez Bustamante, Raul Tonatiuh; Jones, Peter Graham; Jung, Hyungtaik; Jusko, Anton; Kalinak, Peter; Kalweit, Alexander Philipp; Kamin, Jason Adrian; Kang, Ju Hwan; Kaplin, Vladimir; Kar, Somnath; Karasu Uysal, Ayben; Karavichev, Oleg; Karavicheva, Tatiana; Karpechev, Evgeny; Kebschull, Udo Wolfgang; Keidel, Ralf; Keijdener, Darius Laurens; Keil, Markus; Khan, Kamal; Khan, Mohammed Mohisin; Khan, Palash; Khan, Shuaib Ahmad; Khanzadeev, Alexei; Kharlov, Yury; Kileng, Bjarte; Kim, Beomkyu; Kim, Do Won; Kim, Dong Jo; Kim, Hyeonjoong; Kim, Jinsook; Kim, Mimae; Kim, Minwoo; Kim, Se Yong; Kim, Taesoo; Kirsch, Stefan; Kisel, Ivan; Kiselev, Sergey; Kisiel, Adam Ryszard; Kiss, Gabor; Klay, Jennifer Lynn; Klein, Carsten; Klein, Jochen; Klein-Boesing, Christian; Kluge, Alexander; Knichel, Michael Linus; Knospe, Anders Garritt; Kobayashi, Taiyo; Kobdaj, Chinorat; Kofarago, Monika; Kohler, Markus Konrad; Kollegger, Thorsten; Kolozhvari, Anatoly; Kondratev, Valerii; Kondratyeva, Natalia; Kondratyuk, Evgeny; Konevskikh, Artem; Kouzinopoulos, Charalampos; Kovalenko, Vladimir; Kowalski, Marek; Kox, Serge; Koyithatta Meethaleveedu, Greeshma; Kral, Jiri; Kralik, Ivan; Kravcakova, Adela; Krelina, Michal; Kretz, Matthias; Krivda, Marian; Krizek, Filip; Kryshen, Evgeny; Krzewicki, Mikolaj; Kubera, Andrew Michael; Kucera, Vit; Kucheryaev, Yury; Kugathasan, Thanushan; Kuhn, Christian Claude; Kuijer, Paulus Gerardus; Kulakov, Igor; Kumar, Jitendra; Lokesh, Kumar; Kurashvili, Podist; Kurepin, Alexander; Kurepin, Alexey; Kuryakin, Alexey; Kushpil, Svetlana; Kweon, Min Jung; Kwon, Youngil; La Pointe, Sarah Louise; La Rocca, Paola; Lagana Fernandes, Caio; Lakomov, Igor; Langoy, Rune; Lara Martinez, Camilo Ernesto; Lardeux, Antoine Xavier; Lattuca, Alessandra; Laudi, Elisa; Lea, Ramona; Leardini, Lucia; Lee, Graham Richard; Lee, Seongjoo; Legrand, Iosif; Lehnert, Joerg Walter; Lemmon, Roy Crawford; Lenti, Vito; Leogrande, Emilia; Leon Monzon, Ildefonso; Leoncino, Marco; Levai, Peter; Li, Shuang; Li, Xiaomei; Lien, Jorgen Andre; Lietava, Roman; Lindal, Svein; Lindenstruth, Volker; Lippmann, Christian; Lisa, Michael Annan; Ljunggren, Hans Martin; Lodato, Davide Francesco; Lonne, Per-Ivar; Loggins, Vera Renee; Loginov, Vitaly; Loizides, Constantinos; Lopez, Xavier Bernard; Lopez Torres, Ernesto; Lowe, Andrew John; Lu, Xianguo; Luettig, Philipp Johannes; Lunardon, Marcello; Luparello, Grazia; Maevskaya, Alla; Mager, Magnus; Mahajan, Sanjay; Mahmood, Sohail Musa; Maire, Antonin; Majka, Richard Daniel; Malaev, Mikhail; Maldonado Cervantes, Ivonne Alicia; Malinina, Liudmila; Mal'Kevich, Dmitry; Malzacher, Peter; Mamonov, Alexander; Manceau, Loic Henri Antoine; Manko, Vladislav; Manso, Franck; Manzari, Vito; Marchisone, Massimiliano; Mares, Jiri; Margagliotti, Giacomo Vito; Margotti, Anselmo; Margutti, Jacopo; Marin, Ana Maria; Markert, Christina; Marquard, Marco; Martashvili, Irakli; Martin, Nicole Alice; Martin Blanco, Javier; Martinengo, Paolo; Martinez Hernandez, Mario Ivan; Martinez-Garcia, Gines; Martinez Pedreira, Miguel; Martynov, Yevgen; Mas, Alexis Jean-Michel; Masciocchi, Silvia; Masera, Massimo; Masoni, Alberto; Massacrier, Laure Marie; Mastroserio, Annalisa; Matyja, Adam Tomasz; Mayer, Christoph; Mazer, Joel Anthony; Mazzoni, Alessandra Maria; Mcdonald, Daniel; Meddi, Franco; Menchaca-Rocha, Arturo Alejandro; Meninno, Elisa; Mercado-Perez, Jorge; Meres, Michal; Miake, Yasuo; Mieskolainen, Matti Mikael; Mikhaylov, Konstantin; Milano, Leonardo; Milosevic, Jovan; Minervini, Lazzaro Manlio; Mischke, Andre; Mishra, Aditya Nath; Miskowiec, Dariusz Czeslaw; Mitra, Jubin; Mitu, Ciprian Mihai; Mohammadi, Naghmeh; Mohanty, Bedangadas; Molnar, Levente; Montano Zetina, Luis Manuel; Montes Prado, Esther; Morando, Maurizio; Moreira De Godoy, Denise Aparecida; Moretto, Sandra; Morreale, Astrid; Morsch, Andreas; Muccifora, Valeria; Mudnic, Eugen; Muhlheim, Daniel Michael; Muhuri, Sanjib; Mukherjee, Maitreyee; Muller, Hans; Mulligan, James Declan; Gameiro Munhoz, Marcelo; Murray, Sean; Musa, Luciano; Musinsky, Jan; Nandi, Basanta Kumar; Nania, Rosario; Nappi, Eugenio; Naru, Muhammad Umair; Nattrass, Christine; Nayak, Kishora; Nayak, Tapan Kumar; Nazarenko, Sergey; Nedosekin, Alexander; Nellen, Lukas; Ng, Fabian; Nicassio, Maria; Niculescu, Mihai; Niedziela, Jeremi; Nielsen, Borge Svane; Nikolaev, Sergey; Nikulin, Sergey; Nikulin, Vladimir; Noferini, Francesco; Nomokonov, Petr; Nooren, Gerardus; Norman, Jaime; Nyanin, Alexander; Nystrand, Joakim Ingemar; Oeschler, Helmut Oskar; Oh, Saehanseul; Oh, Sun Kun; Ohlson, Alice Elisabeth; Okatan, Ali; Okubo, Tsubasa; Olah, Laszlo; Oleniacz, Janusz; Oliveira Da Silva, Antonio Carlos; Oliver, Michael Henry; Onderwaater, Jacobus; Oppedisano, Chiara; Ortiz Velasquez, Antonio; Oskarsson, Anders Nils Erik; Otwinowski, Jacek Tomasz; Oyama, Ken; Ozdemir, Mahmut; Pachmayer, Yvonne Chiara; Pagano, Paola; Paic, Guy; Pajares Vales, Carlos; Pal, Susanta Kumar; Pan, Jinjin; Pandey, Ashutosh Kumar; Pant, Divyash; Papikyan, Vardanush; Pappalardo, Giuseppe; Pareek, Pooja; Park, Woojin; Parmar, Sonia; Passfeld, Annika; Paticchio, Vincenzo; Paul, Biswarup; Pawlak, Tomasz Jan; Peitzmann, Thomas; Pereira Da Costa, Hugo Denis Antonio; Pereira De Oliveira Filho, Elienos; Peresunko, Dmitry Yurevich; Perez Lara, Carlos Eugenio; Peskov, Vladimir; Pestov, Yury; Petracek, Vojtech; Petrov, Viacheslav; Petrovici, Mihai; Petta, Catia; Piano, Stefano; Pikna, Miroslav; Pillot, Philippe; Pinazza, Ombretta; Pinsky, Lawrence; Piyarathna, Danthasinghe; Ploskon, Mateusz Andrzej; Planinic, Mirko; Pluta, Jan Marian; Pochybova, Sona; Podesta Lerma, Pedro Luis Manuel; Poghosyan, Martin; Polishchuk, Boris; Poljak, Nikola; Poonsawat, Wanchaloem; Pop, Amalia; Porteboeuf, Sarah Julie; Porter, R Jefferson; Pospisil, Jan; Prasad, Sidharth Kumar; Preghenella, Roberto; Prino, Francesco; Pruneau, Claude Andre; Pshenichnov, Igor; Puccio, Maximiliano; Puddu, Giovanna; Pujahari, Prabhat Ranjan; Punin, Valery; Putschke, Jorn Henning; Qvigstad, Henrik; Rachevski, Alexandre; Raha, Sibaji; Rajput, Sonia; Rak, Jan; Rakotozafindrabe, Andry Malala; Ramello, Luciano; Raniwala, Rashmi; Raniwala, Sudhir; Rasanen, Sami Sakari; Rascanu, Bogdan Theodor; Rathee, Deepika; Razazi, Vahedeh; Read, Kenneth Francis; Real, Jean-Sebastien; Redlich, Krzysztof; Reed, Rosi Jan; Rehman, Attiq Ur; Reichelt, Patrick Simon; Reicher, Martijn; Reidt, Felix; Ren, Xiaowen; Renfordt, Rainer Arno Ernst; Reolon, Anna Rita; Reshetin, Andrey; Rettig, Felix Vincenz; Revol, Jean-Pierre; Reygers, Klaus Johannes; Riabov, Viktor; Ricci, Renato Angelo; Richert, Tuva Ora Herenui; Richter, Matthias Rudolph; Riedler, Petra; Riegler, Werner; Riggi, Francesco; Ristea, Catalin-Lucian; Rivetti, Angelo; Rocco, Elena; Rodriguez Cahuantzi, Mario; Rodriguez Manso, Alis; Roeed, Ketil; Rogochaya, Elena; Rohr, David Michael; Roehrich, Dieter; Romita, Rosa; Ronchetti, Federico; Ronflette, Lucile; Rosnet, Philippe; Rossi, Andrea; Roukoutakis, Filimon; Roy, Ankhi; Roy, Christelle Sophie; Roy, Pradip Kumar; Rubio Montero, Antonio Juan; Rui, Rinaldo; Russo, Riccardo; Ryabinkin, Evgeny; Ryabov, Yury; Rybicki, Andrzej; Sadovskiy, Sergey; Safarik, Karel; Sahlmuller, Baldo; Sahoo, Pragati; Sahoo, Raghunath; Sahoo, Sarita; Sahu, Pradip Kumar; Saini, Jogender; Sakai, Shingo; Saleh, Mohammad Ahmad; Salgado Lopez, Carlos Alberto; Salzwedel, Jai Samuel Nielsen; Sambyal, Sanjeev Singh; Samsonov, Vladimir; Sanchez Castro, Xitzel; Sandor, Ladislav; Sandoval, Andres; Sano, Masato; Santagati, Gianluca; Sarkar, Debojit; Scapparone, Eugenio; Scarlassara, Fernando; Scharenberg, Rolf Paul; Schiaua, Claudiu Cornel; Schicker, Rainer Martin; Schmidt, Christian Joachim; Schmidt, Hans Rudolf; Schuchmann, Simone; Schukraft, Jurgen; Schulc, Martin; Schuster, Tim Robin; Schutz, Yves Roland; Schwarz, Kilian Eberhard; Schweda, Kai Oliver; Scioli, Gilda; Scomparin, Enrico; Scott, Rebecca Michelle; Seeder, Karin Soraya; Seger, Janet Elizabeth; Sekiguchi, Yuko; Selyuzhenkov, Ilya; Senosi, Kgotlaesele; Seo, Jeewon; Serradilla Rodriguez, Eulogio; Sevcenco, Adrian; Shabanov, Arseniy; Shabetai, Alexandre; Shadura, Oksana; Shahoyan, Ruben; Shangaraev, Artem; Sharma, Ankita; Sharma, Natasha; Shigaki, Kenta; Shtejer Diaz, Katherin; Sibiryak, Yury; Siddhanta, Sabyasachi; Sielewicz, Krzysztof Marek; Siemiarczuk, Teodor; Silvermyr, David Olle Rickard; Silvestre, Catherine Micaela; Simatovic, Goran; Simonetti, Giuseppe; Singaraju, Rama Narayana; Singh, Ranbir; Singha, Subhash; Singhal, Vikas; Sinha, Bikash; Sarkar - Sinha, Tinku; Sitar, Branislav; Sitta, Mario; Skaali, Bernhard; Slupecki, Maciej; Smirnov, Nikolai; Snellings, Raimond; Snellman, Tomas Wilhelm; Soegaard, Carsten; Soltz, Ron Ariel; Song, Jihye; Song, Myunggeun; Song, Zixuan; Soramel, Francesca; Sorensen, Soren Pontoppidan; Spacek, Michal; Spiriti, Eleuterio; Sputowska, Iwona Anna; Spyropoulou-Stassinaki, Martha; Srivastava, Brijesh Kumar; Stachel, Johanna; Stan, Ionel; Stefanek, Grzegorz; Steinpreis, Matthew Donald; Stenlund, Evert Anders; Steyn, Gideon Francois; Stiller, Johannes Hendrik; Stocco, Diego; Strmen, Peter; Alarcon Do Passo Suaide, Alexandre; Sugitate, Toru; Suire, Christophe Pierre; Suleymanov, Mais Kazim Oglu; Sultanov, Rishat; Sumbera, Michal; Symons, Timothy; Szabo, Alexander; Szanto De Toledo, Alejandro; Szarka, Imrich; Szczepankiewicz, Adam; Szymanski, Maciej Pawel; Takahashi, Jun; Tanaka, Naoto; Tangaro, Marco-Antonio; Tapia Takaki, Daniel Jesus; Tarantola Peloni, Attilio; Tariq, Mohammad; Tarzila, Madalina-Gabriela; Tauro, Arturo; Tejeda Munoz, Guillermo; Telesca, Adriana; Terasaki, Kohei; Terrevoli, Cristina; Teyssier, Boris; Thaeder, Jochen Mathias; Thomas, Deepa; Tieulent, Raphael Noel; Timmins, Anthony Robert; Toia, Alberica; Trogolo, Stefano; Trubnikov, Victor; Trzaska, Wladyslaw Henryk; Tsuji, Tomoya; Tumkin, Alexandr; Turrisi, Rosario; Tveter, Trine Spedstad; Ullaland, Kjetil; Uras, Antonio; Usai, Gianluca; Utrobicic, Antonija; Vajzer, Michal; Vala, Martin; Valencia Palomo, Lizardo; Vallero, Sara; Van Der Maarel, Jasper; Van Hoorne, Jacobus Willem; Van Leeuwen, Marco; Vanat, Tomas; Vande Vyvre, Pierre; Varga, Dezso; Diozcora Vargas Trevino, Aurora; Vargyas, Marton; Varma, Raghava; Vasileiou, Maria; Vasiliev, Andrey; Vauthier, Astrid; Vechernin, Vladimir; Veen, Annelies Marianne; Veldhoen, Misha; Velure, Arild; Venaruzzo, Massimo; Vercellin, Ermanno; Vergara Limon, Sergio; Vernet, Renaud; Verweij, Marta; Vickovic, Linda; Viesti, Giuseppe; Viinikainen, Jussi Samuli; Vilakazi, Zabulon; Villalobos Baillie, Orlando; Vinogradov, Alexander; Vinogradov, Leonid; Vinogradov, Yury; Virgili, Tiziano; Vislavicius, Vytautas; Viyogi, Yogendra; Vodopyanov, Alexander; Volkl, Martin Andreas; Voloshin, Kirill; Voloshin, Sergey; Volpe, Giacomo; Von Haller, Barthelemy; Vorobyev, Ivan; Vranic, Danilo; Vrlakova, Janka; Vulpescu, Bogdan; Vyushin, Alexey; Wagner, Boris; Wagner, Jan; Wang, Hongkai; Wang, Mengliang; Wang, Yifei; Watanabe, Daisuke; Weber, Michael; Weber, Steffen Georg; Wessels, Johannes Peter; Westerhoff, Uwe; Wiechula, Jens; Wikne, Jon; Wilde, Martin Rudolf; Wilk, Grzegorz Andrzej; Wilkinson, Jeremy John; Williams, Crispin; Windelband, Bernd Stefan; Winn, Michael Andreas; Yaldo, Chris G; Yamaguchi, Yorito; Yang, Hongyan; Yang, Ping; Yano, Satoshi; Yasnopolskiy, Stanislav; Yin, Zhongbao; Yokoyama, Hiroki; Yoo, In-Kwon; Yurchenko, Volodymyr; Yushmanov, Igor; Zaborowska, Anna; Zaccolo, Valentina; Zaman, Ali; Zampolli, Chiara; Correia Zanoli, Henrique Jose; Zaporozhets, Sergey; Zarochentsev, Andrey; Zavada, Petr; Zavyalov, Nikolay; Zbroszczyk, Hanna Paulina; Zgura, Sorin Ion; Zhalov, Mikhail; Zhang, Haitao; Zhang, Xiaoming; Zhang, Yonghong; Zhao, Chengxin; Zhigareva, Natalia; Zhou, Daicui; Zhou, You; Zhou, Zhuo; Zhu, Hongsheng; Zhu, Jianhui; Zhu, Xiangrong; Zichichi, Antonino; Zimmermann, Alice; Zimmermann, Markus Bernhard; Zinovjev, Gennady; Zyzak, Maksym
2015-08-17
The measurement of the mass differences for systems bound by the strong force has reached a very high precision with protons and anti-protons. The extension of such measurement from (anti-)baryons to (anti-)nuclei allows one to probe any difference in the interactions between nucleons and anti-nucleons encoded in the (anti-)nuclei masses. This force is a remnant of the underlying strong interaction among quarks and gluons and can be described by effective theories, but cannot yet be directly derived from quantum chromodynamics. Here we report a measurement of the difference between the ratios of the mass and charge of deuterons (d) and anti-deuterons ($\\bar{d}$), and $^{3}{\\rm He}$ and $^3\\overline{\\rm He}$ nuclei carried out with the ALICE (A Large Ion Collider Experiment) detector in Pb-Pb collisions at a centre-of-mass energy per nucleon pair of 2.76 TeV. Our direct measurement of the mass-over-charge differences confirm CPT invariance to an unprecedented precision in the sector of light nuclei. This funda...
From the stable to the exotic: clustering in light nuclei
Beck, C
2016-01-01
A great deal of research work has been undertaken in alpha-clustering study since the pioneering discovery of 12C+12C molecular resonances half a century ago. Our knowledge on physics of nuclear molecules has increased considerably and nuclear clustering remains one of the most fruitful domains of nuclear physics, facing some of the greatest challenges and opportunities in the years ahead. The occurrence of "exotic" shapes in light N=Z alpha-like nuclei is investigated. Various approaches of the superdeformed and hyperdeformed bands associated with quasimolecular resonant structures are presented. Evolution of clustering from stability to the drip-lines is examined: clustering aspects are, in particular, discussed for light exotic nuclei with large neutron excess such as neutron-rich Oxygen isotopes with their complete spectroscopy.
Electric Dipole Moments of Light Nuclei from Chiral EFT
Higa, Renato
2012-01-01
Recent calculations of EDMs of light nuclei in the framework of chiral effective field theory are presented. We argue that they can be written in terms of the leading six low-energy constants encoding CP-violating physics. EDMs of the deuteron, triton, and helion are explicitly given in order to corroborate our claim. An eventual non-zero measurement of these EDMs can be used to disentangle the different sources and strengths of CP-violation.
Fusion Enhancement for Neutron-Rich Light Nuclei
Singh, Varinderjit; Steinbach, T K; Hudan, S; deSouza, R T; Baby, L T; Kuvin, S A; Tripathi, V; Wiedenhover, I
2016-01-01
Measurement of the fusion cross-section for neutron-rich light nuclei is crucial in ascertaining if fusion of these nuclei occurs in the outer crust of a neutron star. The fusion excitation function at near-barrier energies for the $^{19}$O + $^{12}$C system was measured and the experimental results are compared to the fusion excitation function of $^{18}$O + $^{12}$C and $^{16}$O + $^{12}$C. The experiment was performed by utilizing a beam of $^{19}$O, produced via the $^{18}$O(d,p) reaction, to bombard a $^{12}$C target at energies near the Coulomb barrier. Evaporation residues produced in fusion of $^{18,19}$O ions with $^{12}$C target nuclei were detected with good geometric efficiency and identified by measuring their energy and time-of-flight. A significant enhancement is observed in the fusion probability of $^{19}$O ions with a $^{12}$C target as compared to $^{18}$O ions. The larger cross-sections observed at near barrier energies is related to significant narrowing of the fusion barrier indicating a...
Strictly finite-range potential for light and heavy nuclei
Salamon, P.; Lovas, R. G.; Betan, R. M. Id; Vertse, T.; Balkay, L.
2014-05-01
Strictly finite-range (SFR) potentials are exactly zero beyond their finite range. Single-particle energies and densities, as well as S-matrix pole trajectories, are studied in a few SFR potentials suited for the description of neutrons interacting with light and heavy nuclei. The SFR potentials considered are the standard cutoff Woods-Saxon (CWS) potentials and two potentials approaching zero smoothly: the SV potential introduced by Salamon and Vertse [Phys. Rev. C 77, 037302 (2008), 10.1103/PhysRevC.77.037302] and the SS potential of Sahu and Sahu [Int. J. Mod. Phys. E 21, 1250067 (2012), 10.1142/S021830131250067X]. The parameters of these latter potentials were set so that the potentials may be similar to the CWS shape. The range of the SV and SS potentials scales with the cube root of the mass number of the core like the nuclear radius itself. For light nuclei a single term of the SV potential (with a single parameter) is enough for a good description of the neutron-nucleus interaction. The trajectories are compared with a benchmark for which the starting points (belonging to potential depth zero) can be determined independently. Even the CWS potential is found to conform to this benchmark if the range is identified with the cutoff radius. For the CWS potentials some trajectories show irregular shapes, while for the SV and SS potentials all trajectories behave regularly.
Ab initio calculations of reactions of light nuclei
Hupin, Guillaume; Quaglioni, Sofia; Navrátil, Petr
2017-09-01
An ab initio (i.e., from first principles) theoretical framework capable of providing a unified description of the structure and low-energy reaction properties of light nuclei is desirable as a support tool for accurate evaluations of crucial reaction data for nuclear astrophysics, fusion-energy research, and other applications. We present an efficient many-body approach to nuclear bound and scattering states alike, known as the ab initio no-core shell model with continuum. In this approach, square-integrable energy eigenstates of the A-nucleon system are coupled to (A-A)+A target-plus-projectile wave functions in the spirit of the resonating group method to obtain an efficient description of the many-body nuclear dynamics both at short and medium distances and at long ranges. We show that predictive results for nucleon and deuterium scattering on 4He nuclei can be obtained from the direct solution of the Schröedinger equation with modern nuclear potentials.
Elastic scattering, fusion, and breakup of light exotic nuclei
Energy Technology Data Exchange (ETDEWEB)
Kolata, J.J. [University of Notre Dame, Physics Department, Notre Dame, IN (United States); Guimaraes, V. [Universidade de Sao Paulo, Instituto de Fisica, Sao Paulo, SP (Brazil); Aguilera, E.F. [Instituto Nacional de Investigaciones Nucleares, Departamento de Aceleradores, Mexico, Distrito Federal (Mexico)
2016-05-15
The present status of fusion reactions involving light (A< 20) radioactive projectiles at energies around the Coulomb barrier (E<10 MeV per nucleon) is reviewed, emphasizing measurements made within the last decade. Data on elastic scattering (providing total reaction cross section information) and breakup channels for the involved systems, demonstrating the relationship between these and the fusion channel, are also reviewed. Similarities and differences in the behavior of fusion and total reaction cross section data concerning halo nuclei, weakly-bound but less exotic projectiles, and strongly-bound systems are discussed. One difference in the behavior of fusion excitation functions near the Coulomb barrier seems to emerge between neutron-halo and proton-halo systems. The role of charge has been investigated by comparing the fusion excitation functions, properly scaled, for different neutron- and proton-rich systems. Possible physical explanations for the observed differences are also reviewed. (orig.)
Ab initio theories for light nuclei and neutron stars
Gezerlis, Alexandros
2016-09-01
In this talk I will touch upon several features of modern ab initio low-energy nuclear theory. I will start by discussing what ``ab initio'' means in this context. Specifically, I will spend some time going over nucleon-nucleon and three-nucleon interactions and their connections with the underlying theory of Quantum Chromodynamics. I will then show how these interactions are used to describe light nuclei using essentially exact few-body methods. I will then discuss heavier systems, especially those of astrophysical relevance, as well as the methods used to tackle them. This work was supported by the Natural Sciences and Engineering Research Council (NSERC) of Canada and the Canada Foundation for Innovation (CFI).
The Magnetic Structure of Light Nuclei from Lattice QCD
Chang, Emmanuel; Orginos, Kostas; Parreno, Assumpta; Savage, Martin J; Tiburzi, Brian C; Beane, Silas R
2015-01-01
Lattice QCD with background magnetic fields is used to calculate the magnetic moments and magnetic polarizabilities of the nucleons and of light nuclei with $A\\le4$, along with the cross-section for the $M1$ transition $np\\rightarrow d\\gamma$, at the flavor SU(3)-symmetric point where the pion mass is $m_\\pi\\sim 806$ MeV. These magnetic properties are extracted from nucleon and nuclear energies in six uniform magnetic fields of varying strengths. The magnetic moments are presented in a recent Letter. For the charged states, the extraction of the polarizability requires careful treatment of Landau levels, which enter non-trivially in the method that is employed. The nucleon polarizabilities are found to be of similar magnitude to their physical values, with $\\beta_p=5.22(+0.66/-0.45)(0.23) \\times 10^{-4}$ fm$^3$ and $\\beta_n=1.253(+0.056/-0.067)(0.055) \\times 10^{-4}$ fm$^3$, exhibiting a significant isovector component. The dineutron is bound at these heavy quark masses and its magnetic polarizability, $\\beta...
Improved variational many-body wave function in light nuclei
Usmani, Q. N.; Singh, A.; Anwar, K.; Rawitscher, G.
2009-09-01
We propose and implement a simple method for improving the variational wave function of a many-body system. We have obtained a significant improvement in the binding energies, wave functions, and variance for the light nuclei H3, He4, and Li6, using the fully realistic Argonne (AV18) two-body and Urbana-IX (UIX) three-body interactions. The energy of He4 was improved by about 0.2 MeV and the Li6 binding energy was increased by ≈1.7 MeV compared to earlier variational Monte Carlo results. The latter result demonstrates the significant progress achieved by our method, and detailed analyses of the improved results are given. With central interactions the results are found to be in agreement with the “exact” calculations. Our study shows that the relative error in the many-body wave functions, compared to two-body pair correlations, increases rapidly at least proportionally to the number of pairs in the system. However, this error does not increase indefinitely since the pair interactions saturate owing to convergence of cluster expansion.
Unified studies of structure and reactions in light unstable nuclei
Directory of Open Access Journals (Sweden)
Ito Makoto
2016-01-01
Full Text Available The generalized two-center cluster model (GTCM, which can treat covalent, ionic and atomic configurations in general systems with two inert cores plus valence nucleons, is formulated in the basis of the microscopic cluster model. In this model, the covalent configurations constructed by the molecular orbital (MO method and the atomic (or ionic configuration obtained by the valence bonding (VB method can be described in a consistent manner. GTCM is applied to the light neutron-rich system, 10,12Be = α + α + XN (X = 2,4, and the unified studies of the structural changes and the reaction problem are performed. In the structure study, the calculated energy levels are characterized in terms of the chemical bonding like structures, such as the covalent MO or ionic VB structures. The chemical bonding structures changes from level to level within a small energy interval. In the unbound region, the structure problem with the total system of α + α + XN and the reaction problem, induced by the collision of an asymptotic VB state of α+6,8He, are combined by GTCM. The properties of unbound resonant states are discussed in a close connection to the reaction mechanism, and some enhancement factors originated from the properties of the intrinsic states are predicted in the reaction observables. The unified calculation of the structures and the reactions is applied to the Coulomb shift problem in the mirror system, such the 10Be and 10C nuclei. The Coulomb displacement energy of the mirror systems are discussed.
Evaluation of Coulomb Energy Difference for Light Mirror Nuclei Using Slater—Type Orbitals
Institute of Scientific and Technical Information of China (English)
F.Oner; R.A.Mamedoy
2002-01-01
Behavior of the Coulomb energy difference for light nuclei is explained in terms of the different values of the average Coulomb interaction between two particles.Coulomb energy difference according to shell model of light mirror nuclei in the Coulomb and exchange integrals in the formula can be explained with exponential-type wavefunctions.In this study,using the one-center expansion of exponential-type wavefunctions in terms of Slater-type orbitals with the same center,we derived formula for Coulomb energy difference of light mirror nuclei.
MCNP6 Simulation of Light and Medium Nuclei Fragmentation at Intermediate Energies
Energy Technology Data Exchange (ETDEWEB)
Mashnik, Stepan Georgievich [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kerby, Leslie Marie [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Univ. of Idaho, Moscow, ID (United States)
2015-08-24
Fragmentation reactions induced on light and medium nuclei by protons and light nuclei of energies around 1 GeV/nucleon and below are studied with the Los Alamos transport code MCNP6 and with its CEM03.03 and LAQGSM03.03 event generators. CEM and LAQGSM assume that intermediate-energy fragmentation reactions on light nuclei occur generally in two stages. The first stage is the intranuclear cascade (INC), followed by the second, Fermi breakup disintegration of light excited residual nuclei produced after the INC. CEM and LAQGSM account also for coalescence of light fragments (complex particles) up to sup>4He from energetic nucleons emitted during INC. We investigate the validity and performance of MCNP6, CEM, and LAQGSM in simulating fragmentation reactions at intermediate energies and discuss possible ways of further improving these codes.
MCNP6 simulation of light and medium nuclei fragmentation at intermediate energies
Directory of Open Access Journals (Sweden)
Mashnik Stepan G.
2016-01-01
Full Text Available Fragmentation reactions induced on light and medium nuclei by protons and light nuclei of energies around 1 GeV/nucleon and below are studied with the Los Alamos transport code MCNP6 and with its CEM03.03 and LAQGSM03.03 event generators. CEM and LAQGSM assume that intermediate-energy fragmentation reactions on light nuclei occur generally in two stages. The first stage is the intranuclear cascade (INC, followed by the second, Fermi breakup disintegration of light excited residual nuclei produced after the INC. CEM and LAQGSM account also for coalescence of light fragments (complex particles up to 4He from energetic nucleons emitted during INC. We investigate the validity and performance of MCNP6, CEM, and LAQGSM in simulating fragmentation reactions at intermediate energies and discuss possible ways of further improving these codes.
MCNP6 simulation of light and medium nuclei fragmentation at intermediate energies
Mashnik, Stepan G
2015-01-01
Fragmentation reactions induced on light and medium nuclei by protons and light nuclei of energies around 1 GeV/nucleon and below are studied with the Los Alamos transport code MCNP6 and with its CEM03.03 and LAQGSM03.03 event generators. CEM and LAQGSM assume that intermediate-energy fragmentation reactions on light nuclei occur generally in two stages. The first stage is the intranuclear cascade (INC), followed by the second, Fermi breakup disintegration of light excited residual nuclei produced after the INC. CEM and LAQGSM account also for coalescence of light fragments (complex particles) up to 4He from energetic nucleons emitted during INC. We investigate the validity and performance of MCNP6, CEM, and LAQGSM in simulating fragmentation reactions at intermediate energies and discuss possible ways of further improving these codes
MCNP6 simulation of light and medium nuclei fragmentation at intermediate energies
Mashnik, Stepan G.; Kerby, Leslie M.
2016-05-01
Fragmentation reactions induced on light and medium nuclei by protons and light nuclei of energies around 1 GeV/nucleon and below are studied with the Los Alamos transport code MCNP6 and with its CEM03.03 and LAQGSM03.03 event generators. CEM and LAQGSM assume that intermediate-energy fragmentation reactions on light nuclei occur generally in two stages. The first stage is the intranuclear cascade (INC), followed by the second, Fermi breakup disintegration of light excited residual nuclei produced after the INC. CEM and LAQGSM account also for coalescence of light fragments (complex particles) up to 4He from energetic nucleons emitted during INC. We investigate the validity and performance of MCNP6, CEM, and LAQGSM in simulating fragmentation reactions at intermediate energies and discuss possible ways of further improving these codes.
Structure and reactions of light neutron rich nuclei
Energy Technology Data Exchange (ETDEWEB)
Esbensen, H.
1993-01-01
Radioactive beam experiments have made it possible to study the structure of nuclei at the neutron drip line. Pair correlations play a crucial role in such nuclei and characteristic features include an extended neutron halo density and a large dipole strength near threshold. The most detailed studies have been performed for [sup 11]Li. I will present a 3-body model that explains the main features of the data obtained for this nucleus.
Structure and reactions of light neutron rich nuclei
Energy Technology Data Exchange (ETDEWEB)
Esbensen, H.
1993-04-01
Radioactive beam experiments have made it possible to study the structure of nuclei at the neutron drip line. Pair correlations play a crucial role in such nuclei and characteristic features include an extended neutron halo density and a large dipole strength near threshold. The most detailed studies have been performed for {sup 11}Li. I will present a 3-body model that explains the main features of the data obtained for this nucleus.
Search for Beta Decay of the Neutron Halo in Light Nuclei
2002-01-01
The low binding energies of the last neutrons in neutron-rich nuclei lead to the formation of a neutron halo around the nuclear core. We are looking in light nuclei for beta-decay of the neutrons in the halo, a process which in $^1
N3LO NN interaction adjusted to light nuclei in ab exitu approach
Shirokov, A. M.; Shin, I. J.; Kim, Y.; Sosonkina, M.; Maris, P.; Vary, J. P.
2016-10-01
We use phase-equivalent transformations to adjust off-shell properties of similarity renormalization group evolved chiral effective field theory NN interaction (Idaho N3LO) to fit selected binding energies and spectra of light nuclei in an ab exitu approach. We then test the transformed interaction on a set of additional observables in light nuclei to verify that it provides reasonable descriptions of these observables with an apparent reduced need for three- and many-nucleon interactions.
Unstable nuclei in dissociation of light stable and radioactive nuclei in nuclear track emulsion
Artemenkov, D A; Zarubin, P I
2016-01-01
A role of the unstable nuclei ${}^{6}$Be, ${}^{8}$Be and ${}^{9}$B in the dissociation of relativistic nuclei ${}^{7,9}$Be, ${}^{10}$B and ${}^{10,11}$C is under study on the basis of nuclear track emulsion exposed to secondary beams of the JINR Nuclotron. Contribution of the configuration ${}^{6}$Be + $\\mit{n}$ to the ${}^{7}$Be nucleus structure is 8 $\\pm$ 1% which is near the value for the configuration ${}^{6}$Li + $\\mit{p}$. Distributions over the opening angle of $\\alpha$-particle pairs indicate to a simultaneous presence of virtual ${}^{8}$Be$_{g.s.}$ and ${}^{8}$Be$_{2^+}$ states in the ground states of the ${}^{9}$Be and ${}^{10}$C nuclei. The core ${}^{9}$B is manifested in the {${}^{10}$C} nucleus with a probability of 30 $\\pm$ 4%. Selection of the ${}^{10}$C "white" stars accompanied by ${}^{8}$Be$_{g.s.}$ (${}^{9}$B) leads to appearance in the excitation energy distribution of 2$\\alpha$2$\\mit{p}$ "quartets" of the distinct peak with a maximum at 4.1 $\\pm$ 0.3 MeV. ${}^{8}$Be$_{g.s.}$ decays are p...
Unsupervised Transient Light Curve Analysis Via Hierarchical Bayesian Inference
Sanders, Nathan; Soderberg, Alicia
2014-01-01
Historically, light curve studies of supernovae (SNe) and other transient classes have focused on individual objects with copious and high signal-to-noise observations. In the nascent era of wide field transient searches, objects with detailed observations are decreasing as a fraction of the overall known SN population, and this strategy sacrifices the majority of the information contained in the data about the underlying population of transients. A population level modeling approach, simultaneously fitting all available observations of objects in a transient sub-class of interest, fully mines the data to infer the properties of the population and avoids certain systematic biases. We present a novel hierarchical Bayesian statistical model for population level modeling of transient light curves, and discuss its implementation using an efficient Hamiltonian Monte Carlo technique. As a test case, we apply this model to the Type IIP SN sample from the Pan-STARRS1 Medium Deep Survey, consisting of 18,837 photometr...
Three-particle decays of light-nuclei resonances
DEFF Research Database (Denmark)
Álvarez-Rodríguez, R.; Jensen, A.S.; Garrido, E.
2012-01-01
We have studied the three-particle decay of 12C, 9Be and 6Be resonances. These nuclei have been described as three-body systems by means of the complex scaled hyperspherical adiabatic expansion method. The short-distance part of the wave function is responsible for the energies, whereas the infor...
Structure of light neutron-rich nuclei through Coulomb dissociation
Indian Academy of Sciences (India)
U Datta Pramanik; T Aumann; D Cortina; H Emling; H Geissel; M Hellström; R Holzmann; N Iwasa; Y Leifels; G Münzenberg; M Rejmund; C Scheidenberger; K Sümmerer; A Leistenschneider; Th W Elze; A Grünschloss; S Ilievski; K Boretzky; J V Kratz; R Kulessa; E Lubkiewicz; E Wajda; W Walus; P Reiter; H Simon
2001-08-01
Coulomb breakup of neutron-rich nuclei around mass ∼ 20 has been studied experimentally using secondary beams (∼ 500–600 MeV/u) of unstable nuclei produced at GSI. The spectroscopic factor deduced for the neutron occupying 1/2 level in 15C ground state is consistent with the earlier reported value. The data analysis for Coulomb breakup of 17C shows that most of the cross section yields the 16C core in its excited state. For 17-22O, the low-lying E1 strength amounts up to about 12% of the energy weighted dipole sum rule strength depending on neutron excess. The cluster sum rule limit with 16O as a core is almost exhausted for 17,18O, while for more neutron rich isotopes the strength with respect to that limit decreases.
Light nuclei in the vicinity of the dripline and beyond
Energy Technology Data Exchange (ETDEWEB)
Chulkov, L.V. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Kurchatov Institute, Moscow (Russian Federation); Jonson, B.; Zhukov, M.V. [Chalmers Tekniska Hoegskola, Fundamental Fysik, Goeteborg (Sweden)
2015-08-15
After a brief historical overview of the field of physics with radioactive beams, we give an update of the most recent experimental achievements for nuclei at or beyond the nuclear driplines. Long-lived exotic nuclear states are discussed including multi-nucleon radioactivity and exotic isomers. Studies of correlations between decay products in three-body decays and analysis in a Jacobi-coordinate framework are discussed with special emphasis on the difficulty in the interpretations of data obtained in different reactions. We give examples of systematic studies that the vast amount of now existing data allows, such as shell closures, competition between single-particle states in isotopes, isotones and mirror nuclei. The Thomas-Ehrman shift, Garvey-Kelson-type mass relations and IMME analysis of isobaric multiplets with isospin T = 3/2 and 2 are also discussed as well as alternative interpretations in certain cases. (orig.)
The study of initial conditions in collisions of light, intermediate and heavy nuclei
Directory of Open Access Journals (Sweden)
Loctionov A.A.
2017-01-01
Full Text Available The system size dependence for multiparticle processes has been recognized in both cosmic ray (“Stratosphere” collaboration and at accelerator (“EMU” collaboration experiments. The strong enhancement in multiplicity fluctuations for the most central light-light – (C, O, Ne + (C/N/O – collisions has been revealed at JINR-AGS-SPS energies. The sharp difference of light nuclear interactions are interpreted as the sign of intrinsic alpha-clustering in light nuclei.
Interactions of 200 GeV gold nuclei in light elements
Brewster, N. R.; Fickle, R. K.; Waddington, C. J.; Binns, W. R.; Israel, M. H.; Jones, M. D.; Klarmann, J.; Garrard, T. L.; Newport, B. J.; Stone, E. C.
1983-01-01
Total charge-changing cross sections and partial cross-sections for interactions of 200 GeV Au-197 nuclei incident on carbon and polyethylene (CH2) targets have been measured during a calibration of the HEAO-3 Heavy Nuclei Experiment. From these, the total and partial cross-sections for Au-197 incident on hydrogen are inferred. The effects of using these cross-sections in one model of cosmic ray propagation are illustrated. Comparisons to predictions using semi-empirical formulas are shown.
UNSUPERVISED TRANSIENT LIGHT CURVE ANALYSIS VIA HIERARCHICAL BAYESIAN INFERENCE
Energy Technology Data Exchange (ETDEWEB)
Sanders, N. E.; Soderberg, A. M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Betancourt, M., E-mail: nsanders@cfa.harvard.edu [Department of Statistics, University of Warwick, Coventry CV4 7AL (United Kingdom)
2015-02-10
Historically, light curve studies of supernovae (SNe) and other transient classes have focused on individual objects with copious and high signal-to-noise observations. In the nascent era of wide field transient searches, objects with detailed observations are decreasing as a fraction of the overall known SN population, and this strategy sacrifices the majority of the information contained in the data about the underlying population of transients. A population level modeling approach, simultaneously fitting all available observations of objects in a transient sub-class of interest, fully mines the data to infer the properties of the population and avoids certain systematic biases. We present a novel hierarchical Bayesian statistical model for population level modeling of transient light curves, and discuss its implementation using an efficient Hamiltonian Monte Carlo technique. As a test case, we apply this model to the Type IIP SN sample from the Pan-STARRS1 Medium Deep Survey, consisting of 18,837 photometric observations of 76 SNe, corresponding to a joint posterior distribution with 9176 parameters under our model. Our hierarchical model fits provide improved constraints on light curve parameters relevant to the physical properties of their progenitor stars relative to modeling individual light curves alone. Moreover, we directly evaluate the probability for occurrence rates of unseen light curve characteristics from the model hyperparameters, addressing observational biases in survey methodology. We view this modeling framework as an unsupervised machine learning technique with the ability to maximize scientific returns from data to be collected by future wide field transient searches like LSST.
Light nuclei production in relativistic Au+nucleus collisions
Energy Technology Data Exchange (ETDEWEB)
Bennett, M. J. [Yale Univ., A.W. Wright Nuclear Structure Laboratory, New Haven, CT (United States); Pope, J. K. [Yale Univ., A.W. Wright Nuclear Structure Laboratory, New Haven, CT (United States); Beavis, D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Carroll, J. B. [Univ. of California, Los Angeles, CA (United States); Chiba, J. [KEK, Tsukuba (Japan); Chikanian, A. [Yale Univ., A.W. Wright Nuclear Structure Laboratory, New Haven, CT (United States); Crawford, H. J. [Univ. of California, Space Sciences Laboratory, Berkeley, CA (United States); Cronqvist, M. [Univ. of California, Space Sciences Laboratory, Berkeley, CA (United States); Dardenne, Y. [Univ. of California, Space Sciences Laboratory, Berkeley, CA (United States); Kumar, B. S. [Yale Univ., A.W. Wright Nuclear Structure Laboratory, New Haven, CT (United States); Nagle, J. L. [Yale University, A.W. Wright Nuclear Structure Laboratory, New Haven, CT (United States); Debbe, R. [Brookhaven National Lab. (BNL), Upton, NY (United States); Doke, T. [Waseda Univ., Science and Engineering Research Institute, Waseda (Japan); Engelage, J. [Univ. of California, Space Sciences Laboratory, Berkeley, CA (United States); Greiner, L. [Univ. of California, Space Sciences Laboratory, Berkeley, CA (United States); Hayano, R S [University of Tokyo, Tokyo (Japan); Hallman, Timothy J. [Univ. of California, Los Angeles, CA (United States); Heckman, H. H. [E.O. Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Kashiwagi, T. [Waseda Univ., Science and Engineering Research Institute, Waseda (Japan); Kikuchi, J. [Waseda Univ., Science and Engineering Research Institute, Waseda (Japan); Tanaka, K. H. [KEK, Tsukuba (Japan); Kumar, B. S. [Yale Univ., A.W. Wright Nuclear Structure Laboratory, New Haven, CT (United States); Kuo, C. [Univ. of California, Space Sciences Laboratory, Berkeley, CA (United States); Lindstrom, P. J. [E.O. Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Mitchell, J. W. [USRA/Goddard Space Flight Center, Greenbelt, Maryland (United States); Nagamiya, S. [Columbia Univ., Nevis Laboratory, Irvington, NY (United States); Nagle, J. L. [Yale Univ., A.W. Wright Nuclear Structure Laboratory, New Haven, CT (United States); Stankus, P. [Columbia Univ., Nevis Laboratory, Irvington, NY (United States); Tanaka, K. H. [KEK, Tsukuba (Japan); Welsh, R. C. [Johns Hopkins University, Baltimore, MD (United States); Zhan, W. [Columbia Univ., Nevis Laboratory, Irvington, NY (United States)
1998-08-01
We have measured the yields of protons and A=2-4 nuclei in collisions between 10.8 A GeV/ c Au beams and targets of Al, Cu, and Au. The data, which cover a broad rapidity range at low transverse momenta, were measured as a function of collision centrality using a focusing beam line spectrometer and a high-rate centrality detector. We investigate the dependence of coalescence parameters on event geometry. The data are compared with the predictions of an RQMD+coalescence model. {copyright} {ital 1998} {ital The American Physical Society}
Scattering of light halo nuclei on heavy target at energies around the Coulomb barrier
Directory of Open Access Journals (Sweden)
Tengblad O.
2014-03-01
Full Text Available We report here on experiments performed at TRIUMF to study the scattering of the light halo nuclei 11Li on lead at energies below and around the Coulomb barrier. The the elastic and break-up differential cross section are interpreted in the framework of Continuum-Discretized Coupled-Channel calculations. The departure from Rutherford scattering at energies below the barrier is well beyond the behavior of normal nuclei.
Scattering of light halo nuclei on heavy target at energies around the Coulomb barrier
Tengblad O.; Borge M.J.G.; Cubero M.; Nacher E.; Pesudo V.; Perea A.; Gomez-Camacho J.; Moro A. M.; Fernandez-Garcia J.P.; Alvarez M.A.G.; Rodriguez-Gallardo M.; Lay J. A.; Martel I.; Acosta L.; Sanchez-Benitez A.M.
2014-01-01
INPC 2013 – International Nuclear Physics Conference We report here on experiments performed at TRIUMF to study the scattering of the light halo nuclei 11Li on lead at energies below and around the Coulomb barrier. The the elastic and break-up differential cross section are interpreted in the framework of Continuum-Discretized Coupled-Channel calculations. The departure from Rutherford scattering at energies below the barrier is well beyond the behavior of normal nuclei Consejo Interins...
Seeing "the Dress" in the Right Light: Perceived Colors and Inferred Light Sources.
Chetverikov, Andrey; Ivanchei, Ivan
2016-08-01
In the well-known "dress" photograph, people either see the dress as blue with black stripes or as white with golden stripes. We suggest that the perception of colors is guided by the scene interpretation and the inferred positions of light sources. We tested this hypothesis in two online studies using color matching to estimate the colors observers see, while controlling for individual differences in gray point bias and color discrimination. Study 1 demonstrates that the interpretation of the dress corresponds to differences in perceived colors. Moreover, people who perceive the dress as blue-and-black are two times more likely to consider the light source as frontal, than those who see the white-and-gold dress. The inferred light sources, in turn, depend on the circadian changes in ambient light. The interpretation of the scene background as a wall or a mirror is consistent with the perceived colors as well. Study 2 shows that matching provides reliable results on differing devices and replicates the findings on scene interpretation and light sources. Additionally, we show that participants' environmental lighting conditions are an important cue for perceiving the dress colors. The exact mechanisms of how environmental lighting and circadian changes influence the perceived colors of the dress deserve further investigation.
Statistical theory of light nucleus reactions with 1p-shell light nuclei
Xiaojun, Sun; Jingshang, Zhang
2017-09-01
The 1p-shell light elements (Li, Be, B, C, N, and O) had long been selected as the most important materials for improving neutron economy in thermal and fast fission reactors and in the design of accelerator-driven spallation neutron sources. A statistical theory of light nucleus reactions (STLN) is proposed to describe the double-differential cross sections for both neutron and light charged particle induced nuclear reactions with 1p-shell light nuclei. The dynamics of STLN is described by the unified Hauser-Feshbach and exciton model, in which the angular momentum and parity conservations are strictly considered in equilibrium and pre-equilibrium processes. The Coulomb barriers of the incoming and outgoing charged particles, which significantly influence the open channels of the reaction, can be reasonably considered in incident channel and different outgoing channels. In kinematics, the recoiling effects in various emission processes are strictly taken into account. The analytical energy and angular spectra of the reaction products in sequential and simultaneous emission processes are obtained in terms of the new integral formula proposed in our recent paper. Taking 12C(n, xn), 9Be(n, xn), 16O(n, xn), and 9Be(p,xn) reactions as examples, we had calculated the double-differential cross sections of outgoing neutrons and compared with the experimental data. In addition, we had also calculated the partition and total kerma coefficients for 12C(n, xn) and 16O(n, xn) reactions, respectively. The existing experimental data can be remarkably well reproduced by STLN, which had been used to set up file-6 in CENDL database.
Inner Radiation Belt Generation of Light Nuclei Isotope
Galper, A. M.; Koldashov, S. V.; Leonv, A. A.; Mikhailov, V. V.
2003-07-01
Nuclear interactions between inner zone protons and atoms in the upper atmosphere provide the essential source of H and He isotop es nuclei in radiation belt. This paper reports the calculations of these isotop es intensities from the inner zone proton intensity model AP-8, the atmosphere drift-averaged composition and densities model MSIS-90, and cross sections for the various interaction processes. To calculate drift-averaged densities and energy losses of secondaries the particles are traced in geomagnetic field according IGRF-95 model by numerical solution of motion equation. The calculations account for nuclear interactions kinematic along the whole trapped protons trajectories. The results of calculations are compared with experimental data from SAMPEX, CRRES, RESURS-04 and MITA satellites taken during different solar activity phases. The comparison with observational data shows that the atmosphere is sufficient source for inner zone 4 He, 3 He,2 H and 3 H for L-shell less than 1.3.
Energy Technology Data Exchange (ETDEWEB)
Furusawa, Shun; Yamada, Shoichi [Advanced Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555 (Japan); Sumiyoshi, Kohsuke [Numazu College of Technology, Ooka 3600, Numazu, Shizuoka 410-8501 (Japan); Suzuki, Hideyuki, E-mail: furusawa@heap.phys.waseda.ac.jp [Faculty of Science and Technology, Tokyo University of Science, Yamazaki 2641, Noda, Chiba 278-8510 (Japan)
2013-08-01
We construct new equations of state for baryons at subnuclear densities for the use in core-collapse simulations of massive stars. The abundance of various nuclei is obtained together with thermodynamic quantities. A model free energy is constructed, based on the relativistic mean field theory for nucleons and the mass formula for nuclei with the proton number up to {approx}1000. The formulation is an extension of the previous model, in which we adopted the liquid drop model to all nuclei under the nuclear statistical equilibrium. We reformulate the new liquid drop model so that the temperature dependences of bulk energies could be taken into account. Furthermore, we extend the region in the nuclear chart, in which shell effects are included, by using theoretical mass data in addition to experimental ones. We also adopt a quantum-theoretical mass evaluation of light nuclei, which incorporates the Pauli- and self-energy shifts that are not included in the ordinary liquid drop model. The pasta phases for heavy nuclei are taken into account in the same way as in the previous model. We find that the abundances of heavy nuclei are modified by the shell effects of nuclei and temperature dependence of bulk energies. These changes may have an important effect on the rates of electron captures and coherent neutrino scatterings on nuclei in supernova cores. The abundances of light nuclei are also modified by the new mass evaluation, which may affect the heating and cooling rates of supernova cores and shocked envelopes.
Axial-Current Matrix Elements in Light Nuclei from Lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Savage, Martin [Univ. of Washington, Seattle, WA (United States); Shanahan, Phiala E. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Tiburzi, Brian C. [Univ. of Maryland, College Park, MD (United States); Wagman, Michael L. [Univ. of Washington, Seattle, WA (United States); Winter, Frank T. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Beane, Silas [Univ. of New Hampshire, Durham, NH (United States); Chang, Emmanuel [Univ. of Washington, Seattle, WA (United States); Davoudi, Zohreh; Detmold, William [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Orginos, Konstantinos [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); College of William and Mary, Williamsburg, VA (United States)
2016-12-01
I present results from the first lattice QCD calculations of axial-current matrix elements in light nuclei, performed by the NPLQCD collaboration. Precision calculations of these matrix elements, and the subsequent extraction of multi-nucleon axial-current operators, are essential in refining theoretical predictions of the proton-proton fusion cross section, neutrino-nucleus cross sections and $\\beta\\beta$-decay rates of nuclei. In addition, they are expected to shed light on the phenomenological quenching of $g_A$ that is required in nuclear many-body calculations.
Axial-Current Matrix Elements in Light Nuclei from Lattice QCD
Savage, Martin J; Tiburzi, Brian C; Wagman, Michael L; Winter, Frank; Beane, Silas R; Chang, Emmanuel; Davoudi, Zohreh; Detmold, William; Orginos, Kostas
2016-01-01
I present results from the first lattice QCD calculations of axial-current matrix elements in light nuclei, performed by the NPLQCD collaboration. Precision calculations of these matrix elements, and the subsequent extraction of multi-nucleon axial-current operators, are essential in refining theoretical predictions of the proton-proton fusion cross section, neutrino-nucleus cross sections and $\\beta\\beta$-decay rates of nuclei. In addition, they are expected to shed light on the phenomenological quenching of $g_A$ that is required in nuclear many-body calculations.
Deformation change in light iridium nuclei from laser spectroscopy
Energy Technology Data Exchange (ETDEWEB)
Verney, D.; Le Blanc, F.; Obert, J.; Oms, J.; Puteaux, J.C.; Roussiere, B.; Sauvage, J. [IN2P3-CNRS/Universite Paris Sud-XI, Institut de Physique Nucleaire, Orsay Cedex (France); Cabaret, L.; Duong, H.T.; Pinard, J. [CNRS, Laboratoire Aime Cotton, Orsay Cedex (France); Crawford, J.E.; Lee, J.K.P. [McGill University, Physics Department, Montreal (Canada); Fricke, B.; Rashid, K. [Institut fuer Theoretische Physik der Universitaet Kassel, Kassel (Germany); Genevey, J.; Ibrahim, F. [IN2P3-CNRS/Universite Joseph Fourier-Grenoble I, Laboratoire de Physique Subatomique et de Cosmologie, Grenoble Cedex (France); Huber, G.; Krieg, M.; Sebastian, V. [Institut fuer Physik der Universitaet Mainz, Mainz (Germany); Le Scornet, G.; Lunney, D. [IN2P3-CNRS/Universite Paris Sud-XI, Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse, Orsay Cedex (France)
2006-12-15
Laser spectroscopy measurements have been performed on neutron-deficient and stable Ir isotopes using the COMPLIS experimental setup installed at ISOLDE-CERN. The radioactive Ir atoms were obtained from successive decays of a mass-separated Hg beam deposited onto a carbon substrate after deceleration to 1kV and subsequently laser desorbed. A three-color, two-step resonant scheme was used to selectively ionize the desorbed Ir atoms. The hyperfine structure (HFS) and isotope shift (IS) of the first transition of the ionization path 5d{sup 7}6s{sup 24}F{sub 9/2}{yields}5d{sup 7}6s6p{sup 6}F{sub 11/2} at 351.5nm were measured for {sup 182-189}Ir, {sup 186}Ir{sup m} and the stable {sup 191,193}Ir. The nuclear magnetic moments {mu}{sub I} and the spectroscopic quadrupole moments Q{sub s} were obtained from the HFS spectra and the change of the mean square charge radii from the IS measurements. The sign of {mu}{sub I} was experimentally determined for the first time for the masses 182{<=}A{<=}189 and the isomeric state {sup 186}Ir{sup m}. The spectroscopic quadrupole moments of {sup 182}Ir and {sup 183}Ir were measured also for the first time. A large mean square charge radius change between {sup 187}Ir and {sup 186}Ir{sup g} and between {sup 186}Ir{sup m} and {sup 186}Ir{sup g} was observed corresponding to a sudden increase in deformation: from {beta}{sub 2}{approx_equal}+0.16 for the heavier group A = 193, 191, 189, 187 and 186m to {beta}{sub 2}{>=}+0.2 for the lighter group A=186g, 185, 184, 183 and 182. These results were analyzed in the framework of a microscopic treatment of an axial rotor plus one or two quasiparticle(s). This sudden deformation change is associated with a change in the proton state that describes the odd-nuclei ground state or that participates in the coupling with the neutron in the odd-odd nuclei. This state is identified with the {pi}3/2 {sup +}[402 ] orbital for the heavier group and with the {pi}1/2{sup -}[541 ] orbital stemming from the 1h
Iwabuchi, Kosei; Takagi, Shingo
2010-08-01
The plant organelles, chloroplast and nucleus, change their position in response to light. In Arabidopsis thaliana leaf cells, chloroplasts and nuclei are distributed along the inner periclinal wall in darkness. In strong blue light, they become positioned along the anticlinal wall, while in weak blue light, only chloroplasts are accumulated along the inner and outer periclinal walls. Blue-light dependent positioning of both organelles is mediated by the blue-light receptor phototropin and controlled by the actin cytoskeleton. Interestingly, however, it seems that chloroplast movement requires short, fine actin filaments organized at the chloroplast edge, whereas nuclear movement does cytoplasmic, thick actin bundles intimately associated with the nucleus. Although there are many similarities between photo-relocation movements of chloroplasts and nuclei, plant cells appear to have evolved distinct mechanisms to regulate actin organization required for driving the movements of these organelles.
Quantum Monte Carlo studies of relativistic effects in light nuclei
Forest, J. L.; Pandharipande, V. R.; Arriaga, A.
1999-07-01
Relativistic Hamiltonians are defined as the sum of relativistic one-body kinetic energy, two- and three-body potentials, and their boost corrections. In this work we use the variational Monte Carlo method to study two kinds of relativistic effects in 3H and 4He, using relativistic Hamiltonians. The first is due to the nonlocalities in the relativistic kinetic energy and relativistic one-pion exchange potential (OPEP), and the second is from boost interaction. The OPEP contribution is reduced by ~15% by the relativistic nonlocality, which may also have significant effects on pion exchange currents. However, almost all of this reduction is canceled by changes in the kinetic energy and other interaction terms, and the total effect of the nonlocalities on the binding energy is very small. The boost interactions, on the other hand, give repulsive contributions of ~0.4 (1.9) MeV in 3H (4He) and account for ~37% of the phenomenological part of the three-nucleon interaction needed in the nonrelativistic Hamiltonians. The wave functions of nuclei are not significantly changed by these effects.
Local chiral potentials and the structure of light nuclei
Piarulli, Maria; Schiavilla, Rocco; Kievsky, Alejandro; Lovato, Alessandro; Marcucci, Laura E; Pieper, Steven C; Viviani, Michele; Wiringa, Robert B
2016-01-01
We present fully local versions of the minimally non-local nucleon-nucleon potentials constructed in a previous paper [M.\\ Piarulli {\\it et al.}, Phys.\\ Rev.\\ C {\\bf 91}, 024003 (2015)], and use them in hypersperical-harmonics and quantum Monte Carlo calculations of ground and excited states of $^3$H, $^3$He, $^4$He, $^6$He, and $^6$Li nuclei. The long-range part of these local potentials includes one- and two-pion exchange contributions without and with $\\Delta$-isobars in the intermediate states up to order $Q^3$ ($Q$ denotes generically the low momentum scale) in the chiral expansion, while the short-range part consists of contact interactions up to order $Q^4$. The low-energy constants multiplying these contact interactions are fitted to the 2013 Granada database in two different ranges of laboratory energies, either 0--125 MeV or 0--200 MeV, and to the deuteron binding energy and $nn$ singlet scattering length. Fits to these data are performed for three models characterized by long- and short-range cutof...
Identification of Light Cosmic-Ray Nuclei with AMS-02
Tomassetti, Nicola
2015-01-01
AMS-02 is a wide acceptance (0.5 m2 sr) and long duration (up to 20 years) magnetic spectrometer operating onboard the International Space Station since May 2011. Its main scientific objectives are the indirect research of Dark Matter, searches of primitive Anti-Matter and the precise measurement of the Cosmic-Ray (CR) spectra. Among charged CR species, AMS-02 will be able to measure relative abundances and absolute fluxes of CRs nuclei from Hydrogen up to at least Iron (Z = 26) in a kinetic energy range from hundreds MeV to TeV per nucleon. The high statistics measurement of the chemical composition of CRs in this extended energy range will reveal new insights about the CRs life in the Galaxy, from their origin to the propagation in the interstellar medium, giving new constraints to astrophysical models of Galactic CRs. The nucleus absolute charge, Z, is measured several times along the trajectory of the particle inside AMS-02 using different detection techniques: in the 9 planes of the Silicon Tracker, in t...
AMS results on the fluxes of light nuclei in cosmic rays
Bertucci, Bruna; AMS Collaboration
2017-01-01
AMS-02 is a wide acceptance high-energy physics experiment installed on the International Space Station in May 2011 and it has been operating continuously since then. AMS-02 is able to separate cosmic rays light nuclei species (1 AMS will be presented, including proton, helium, boron to carbon flux ratio, and highlights of ongoing analyses discussed. On behalf of the AMS Collaboration.
Benchmark calculation of no-core Monte Carlo shell model in light nuclei
Abe, T; Otsuka, T; Shimizu, N; Utsuno, Y; Vary, J P; 10.1063/1.3584062
2011-01-01
The Monte Carlo shell model is firstly applied to the calculation of the no-core shell model in light nuclei. The results are compared with those of the full configuration interaction. The agreements between them are within a few % at most.
Unraveling models of CP violation through electric dipole moments of light nuclei
Dekens, W.; Vries, J. de; Bsaisou, J.; Bernreuther, W.; Hanhart, C.; Meißner, Ulf-G; Nogga, A.; Wirzba, A.
2014-01-01
We show that the proposed measurements of the electric dipole moments of light nuclei in storage rings would put strong constraints on models of flavor-diagonal CP violation. Our analysis is exemplified by a comparison of the Standard Model including the QCD theta term, the minimal left-right symmet
Electric dipole moments of light nuclei from chiral effective field theory
de Vries, J.; Higa, R.; Liu, C. -P.; Mereghetti, E.; Stetcu, I.; Timmermans, R. G. E.; van Kolck, U.
2011-01-01
We set up the framework for the calculation of electric dipole moments (EDMs) of light nuclei using the systematic expansion provided by chiral effective field theory (EFT). We take into account parity (P) and timer-reversal (T) violation which, at the quark-gluon level, originates from the QCD vacu
Data Covariances from R-Matrix Analyses of Light Nuclei
Energy Technology Data Exchange (ETDEWEB)
Hale, G.M., E-mail: ghale@lanl.gov; Paris, M.W.
2015-01-15
After first reviewing the parametric description of light-element reactions in multichannel systems using R-matrix theory and features of the general LANL R-matrix analysis code EDA, we describe how its chi-square minimization procedure gives parameter covariances. This information is used, together with analytically calculated sensitivity derivatives, to obtain cross section covariances for all reactions included in the analysis by first-order error propagation. Examples are given of the covariances obtained for systems with few resonances ({sup 5}He) and with many resonances ({sup 13}C ). We discuss the prevalent problem of this method leading to cross section uncertainty estimates that are unreasonably small for large data sets. The answer to this problem appears to be using parameter confidence intervals in place of standard errors.
Timing Analysis of Light Curves in the Tartarus Active Galactic Nuclei Database
O'Neill, P M; Papadakis, I E; Turner, T J; Neill, Paul M. O'; Nandra, Kirpal; Papadakis, Iossif E.
2004-01-01
The Tartarus database contains products for 529 ASCA observations of active galactic nuclei. We have been updating Tartarus to include observing sequences conducted after 1999 January. The revised database will contain products for 375 objects, with a total of 614 observing sequences. We have begun a systematic timing analysis of the Tartarus light curves. We present here some preliminary results of an investigation into the relation between excess variance and black-hole mass. Having optimised our analysis to minimize the scatter in the variance measurements, we find that the narrow-line active galactic nuclei follow roughly the same relation as the broad-line objects.
Inferred motion perception of light sources in 3D scenes is color-blind.
Gerhard, Holly E; Maloney, Laurence T
2013-01-01
In everyday scenes, the illuminant can vary spatially in chromaticity and luminance, and change over time (e.g. sunset). Such variation generates dramatic image effects too complex for any contemporary machine vision system to overcome, yet human observers are remarkably successful at inferring object properties separately from lighting, an ability linked with estimation and tracking of light field parameters. Which information does the visual system use to infer light field dynamics? Here, we specifically ask whether color contributes to inferred light source motion. Observers viewed 3D surfaces illuminated by an out-of-view moving collimated source (sun) and a diffuse source (sky). In half of the trials, the two sources differed in chromaticity, thereby providing more information about motion direction. Observers discriminated light motion direction above chance, and only the least sensitive observer benefited slightly from the added color information, suggesting that color plays only a very minor role for inferring light field dynamics.
Inferred Motion Perception of Light Sources in 3D Scenes is Color-Blind
Directory of Open Access Journals (Sweden)
Holly E. Gerhard
2013-04-01
Full Text Available In everyday scenes, the illuminant can vary spatially in chromaticity and luminance, and change over time (e.g. sunset. Such variation generates dramatic image effects too complex for any contemporary machine vision system to overcome, yet human observers are remarkably successful at inferring object properties separately from lighting, an ability linked with estimation and tracking of light field parameters. Which information does the visual system use to infer light field dynamics? Here, we specifically ask whether color contributes to inferred light source motion. Observers viewed 3D surfaces illuminated by an out-of-view moving collimated source (sun and a diffuse source (sky. In half of the trials, the two sources differed in chromaticity, thereby providing more information about motion direction. Observers discriminated light motion direction above chance, and only the least sensitive observer benefited slightly from the added color information, suggesting that color plays only a very minor role for inferring light field dynamics.
DEFF Research Database (Denmark)
Møller, Jesper
.1 with the title ‘Inference'.) This contribution concerns statistical inference for parametric models used in stochastic geometry and based on quick and simple simulation free procedures as well as more comprehensive methods using Markov chain Monte Carlo (MCMC) simulations. Due to space limitations the focus...
Evaluation of Coulomb Energy Difference for Light Mirror Nuclei Using Slater-Type Orbitals
Institute of Scientific and Technical Information of China (English)
F. Oner; B.A. Mainedov
2002-01-01
Behavior of the Coulomb energy difference for light nuclei is explained in terms of the different values of theaverage Coulomb interaction between two particles. Coulomb energy difference according to shell model of light mirrornuclei in the Coulomb and exchange integrals in the formula can be explained with exponential-type wavefunctions. Inthis study, using the one-center expansion of exponential-type wavcfunctions in terms of Slater-type orbitals with thesame center, we derived formula for Coulomb energy difference of light mirror mulei.
"Tomography" of the cluster structure of light nuclei via relativistic dissociation
Zarubin, P I
2013-01-01
These lecture notes present the capabilities of relativistic nuclear physics for the development of the physics of nuclear clusters. Nuclear track emulsion continues to be an effective technique for pilot studies that allows one, in particular, to study the cluster dissociation of a wide variety of light relativistic nuclei within a common approach. Despite the fact that the capabilities of the relativistic fragmentation for the study of nuclear clustering were recognized quite a long time ago, electronic experiments have not been able to come closer to an integrated analysis of ensembles of relativistic fragments. The continued pause in the investigation of the "fine" structure of relativistic fragmentation has led to resumption of regular exposures of nuclear emulsions in beams of light nuclei produced for the first time at the Nuclotron of the Joint Institute for Nuclear Research (JINR, Dubna). To date, an analysis of the peripheral interactions of relativistic isotopes of beryllium, boron, carbon and nitr...
Lattice Simulations for Light Nuclei: Chiral Effective Field Theory at Leading Order
Borasoy, B; Krebs, H; Lee, D; Meißner, Ulf G; Borasoy, Bugra; Epelbaum, Evgeny; Krebs, Hermann; Lee, Dean; Mei{\\ss}ner, Ulf-G.
2006-01-01
We discuss lattice simulations of light nuclei at leading order in chiral effective field theory. Using lattice pion fields and auxiliary fields, we include the physics of instantaneous one-pion exchange and the leading-order S-wave contact interactions. We also consider higher-derivative contact interactions which adjust the S-wave scattering amplitude at higher momenta. By construction our lattice path integral is positive definite in the limit of exact Wigner SU(4) symmetry for any even number of nucleons. This SU(4) positivity and the approximate SU(4) symmetry of the low-energy interactions play an important role in suppressing sign and phase oscillations in Monte Carlo simulations. We assess the computational scaling of the lattice algorithm for light nuclei with up to eight nucleons and analyze in detail calculations of the deuteron, triton, and helium-4.
Molecular structures and clustering effects in reactions induced by light nuclei
Beck, C
2014-01-01
$\\alpha$-clustering study since the pioneering discovery of $^{12}$C+$^{12}$C molecular resonances half a century ago. Our knowledge on physics of nuclear molecules has increased considerably and nuclear clustering remains one of the most fruitful domains of nuclear physics, facing some of the greatest challenges and opportunities in the years ahead. The occurrence of "exotic" shapes in light $N$=$Z$ $\\alpha$-like nuclei is investigated. Various approaches of the superdeformed and hyperdeformed bands associated with quasimolecular resonant structures are presented. Evolution of clustering from stability to the drip-lines is examined: clustering aspects are, in particular, discussed for light exotic nuclei with large neutron excess such as neutron-rich Oxygen isotopes with their complete spectrocopy.
Electric Dipole Moments of Light Nuclei From Chiral Effective Field Theory
Higa, R.
2013-08-01
Recent calculations of EDMs of light nuclei in the framework of chiral effective field theory are presented. We argue that they can be written in terms of the leading six low-energy constants encoding CP-violating physics. EDMs of the deuteron, triton, and helion are explicitly given in order to corroborate our claim. An eventual non-zero measurement of these EDMs can be used to disentangle the different sources and strengths of CP-violation.
O'Dowd, Colin D.; Lowe, Jason A.; Smith, Michael H.; Davison, Brian; Hewitt, C. Nicholas; Harrison, Roy M.
1997-06-01
Accumulation mode aerosol properties and biogenic sulphur emissions over the South Atlantic and Antarctic Oceans are examined. Two contrasting air masses, polar and maritime, each possessing distinct aerosol properties, were encountered during the summer months. By examining aerosol volatile properties, polar air masses arriving from the Antarctic continent were shown to consist primarily Of H2SO4 in the accumulation mode size range, with inferred NH+4 to SO=4 molar ratios close to zero. By comparison, air masses of temperate maritime origin were significantly neutralized with molar ratios of ≈1. These results suggest a deficit of ammonia in polar air masses compared with that in maritime air masses. Dimethyl sulphide (DMS) exhibited no correlation with its putative aerosol oxidation products, although spatial coherence in atmospheric concentrations of DMS, methane sulphonic acid (MSA), and non-sea-salt (nss)-sulphate mass was observed. Volatility analysis, used to infer nss-sulphate cloud condensation nuclei (nss-sCCN) active at a supersaturation of ≈0.2%, indicates that nss-sCCN mass and number concentration were best correlated with MSA mass (r≈0.63). Aerosol volatility identified the presence of MSA in submicron non-sea-salt aerosol; however, its contribution to the aerosol mass was small relative to the contribution of sulphuric acid and ammonium bisulphate/sulphate aerosol. The marine sulphur cycle appears strongly coupled to the sea-salt cycle with, typically, 80-90% of nss-sulphate thought to be internally mixed with sea-salt aerosol. During the austral Summer of 1992/1993, a period of strong biological productivity in the Weddell Sea and sub-Antarctic Ocean, particularly during ice-melt, the cruise-average DMS flux of 61 μg m-2 d-1 corresponded to a very modest average nss-sCCN concentration of 21 cm-3. Observed peak values of DMS flux and inferred nss-CCN concentrations during the cruise were 477 μg m-2 d-1 and 64 cm-3, respectively. Events of new
DEFF Research Database (Denmark)
Møller, Jesper
2010-01-01
Chapter 9: This contribution concerns statistical inference for parametric models used in stochastic geometry and based on quick and simple simulation free procedures as well as more comprehensive methods based on a maximum likelihood or Bayesian approach combined with markov chain Monte Carlo...
Transition between nuclear and quark-gluon descriptions of hadrons and light nuclei.
Holt, R J; Gilman, R
2012-08-01
We provide a perspective on studies aimed at observing the transition between hadronic and quark-gluonic descriptions of reactions involving light nuclei. We begin by summarizing the results for relatively simple reactions such as the pion form factor and the neutral pion transition form factor as well as that for the nucleon and end with exclusive photoreactions in our simplest nuclei. A particular focus will be on reactions involving the deuteron. It is noted that a firm understanding of these issues is essential for unravelling important structure information from processes such as deeply virtual Compton scattering as well as deeply virtual meson production. The connection to exotic phenomena such as color transparency will be discussed. A number of outstanding challenges will require new experiments at modern facilities on the horizon as well as further theoretical developments.
Thermonuclear breakup reactions of light nuclei. I - Processes and effects. [in astrophysic plasmas
Guessoum, Nidhal; Gould, Robert J.
1989-01-01
Temperature and density conditions are considered for the occurrence of breakup reactions of light nuclei in astrophysical plasmas. The proton-induced endothermic process is shown to be the principal mechanism for nuclear breakdown in a plasma. The phenomenon occurs at a temperature of about 1 MeV, which is a fraction of the typical binding energy per nucleon in nuclei. The temperature for breakup of He-4 is about twice as large, because of the higher binding energy. Depending on the temperature attained in the plasma, the initial concentration of elements heavier than hydrogen can be depleted. However, if it attains a temperature of about 1 MeV, breaking up the metals (C, N, O, Ne, Mg) but not He-4, an increase in the He-4 abundance by as much as 10 percent can result, since these elements essentially break down to alpha particles.
2017-01-01
This note complements the paper titled: ``Production of deuterons, tritons, $^{3}$He nuclei and their anti-nuclei in pp collisions at $\\sqrt{s}$~=~0.9, 2.76 and 7~TeV'' with additional material related to Monte Carlo simulations necessary to compare the results with lower energy experiments. It describes a coalescence-based afterburner for QCD-inspired event generators, which allows the generation of light nuclei, hyper-nuclei and their charge conjugates in proton--proton (pp) collisions at LHC energies. The event generators with the afterburner are able to reproduce the differential cross sections of light (anti-)nuclei ($A<4)$ with the same degree of agreement as those of protons and anti-protons at the same momentum per nucleon. They also explain the transverse momentum dependence of the coalescence parameters as the result of hard scattering effects.
Enhancement of fusion at near and sub-barrier energies for neutron-rich light nuclei
Singh, Varinderjit; Steinbach, T K; Wiggins, B B; Hudan, S; Lin, R T deSouza Zidu; Horowitz, C J; Baby, L T; Kuvin, S A; Tripathi, Vandana; Wiedenhover, I
2016-01-01
Measurement of the fusion cross-section for neutron-rich light nuclei is crucial in ascertaining if fusion of these nuclei occurs in the outer crust of a neutron star. We have therefore measured the fusion excitation function at near-barrier energies for the 19O + 12C system and compared the experimental results with the fusion excitation function of 18O + 12C and 16O + 12C. In the experiment a beam of 19O, produced via the 18O(d,p) reaction, was incident on a 12C target at energies near the Coulomb barrier. Evaporation residues produced in fusion of 18,19O ions with 12C target nuclei were detected with good geometric efficiency and identified by measuring their energy and time-of-flight. A significant enhancement in the fusion probability of 19O ions with a 12C target as compared to 18O ions is observed. The significantly larger cross-sections observed at near barrier energies are not predicted by a static model of fusion for 19O + 12C indicating that dynamics play an important role in the fusion of neutron-...
Coupled channel alpha decay theory for even- and odd-mass light and heavy nuclei
Energy Technology Data Exchange (ETDEWEB)
Rauscher, E.A.
1978-02-01
Four major approaches to the theoretical calculation of alpha decay widths were examined for light and heavy, even- and odd-mass nuclei. Application of the microscopic shell model rate theory as well as macroscopic models utilizing the coupled-channel formalism were studied. Use of the R-matrix and S-matrix theories have been applied in order to overcome problems involving dependency on the connection radius and nuclear potential parameters of the relative and absolute alpha decay widths. 105 references. (JFP)
Nucleon and cluster knockout reactions induced in light nuclei by intermediate-energy protons
Energy Technology Data Exchange (ETDEWEB)
Vdovin, A.I.; Golovin, A.V.; Loshchakov, I.I.
1987-11-01
Experimental and theoretical studies of nucleon and cluster knockout reactions induced in light nuclei by intermediate-energy (30--150 MeV) protons are reviewed. The methods of theoretical analysis of knockout reactions are considered. The main attention is devoted to the t-matrix approximation with distorted waves. It is shown for the example of cluster knockout reactions how quasielastic and two-step processes can be coherently included in the matrix element when the t-matrix approximation is used.
The meaning of the UHECR Hot Spots: A Light Nuclei Nearby Astronomy
Fargion, Daniele
2014-01-01
We update all the recent UHECR events reported by AUGER, Telescope Array as well as by AGASA in common coordinate maps. We confirm our earliest (2008-2013) model where UHECR are mostly light nuclei (He,Be,B), explaining the Virgo absence and confirming M82 as the main source of North TA Hot Spot. Many more sources , as NGC 253 and galactic ones, are possibly source of most of the 376 UHECR events. Several correlated map, already considered in recent years, are shown with all the events
Plano, Santiago A; Golombek, Diego A; Chiesa, Juan J
2010-03-01
The ability to synchronize to light-dark (LD) cycles is an essential property of the circadian clock, located in mammals within the hypothalamic suprachiasmatic nuclei (SCN). Single light pulses activate nitric oxide (NO) intracellular signaling, leading to circadian phase-shifts required for synchronization. In addition, extracellular NO has a role in the SCN paracrine communication of photic phase advances. In this work, the extracellular nitrergic transmission was assessed in steady-state synchronization to LD cycles of locomotor rhythms in the golden hamster (Mesocricetus auratus). Extracellular NO levels were pharmacologically decreased in vivo with the specific scavenger, 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (PTIO). Hamsters were subjected to LD cycles different from normal 24 h (LD 14 : 10) cycles (i.e. T-cycles), with a single 30-min light pulse presented either every 23 h (T23 cycles), or every 25 h (T25 cycles), thus allowing synchronization by advances or delays, respectively. Acute PTIO intracerebroventricular microinjections, delivered 30 min previous to the light pulse, inhibited synchronization by phase advances to T23 cycles, but did not alter phase delays under T25 cycles. In addition, NO scavenging inhibited light-induced expression of PERIOD1 protein at circadian time 18 (i.e. the time for light-induced phase advances). These findings demonstrate the role of extracellular NO communication within the SCN in the steady-state synchronization to LD cycles.
Inferring asymmetric limb cloudiness on exoplanets from transit light curves
von Paris, P; Bordé, P; Leconte, J; Selsis, F
2016-01-01
Clouds have been shown to be present in many exoplanetary atmospheres. Cloud formation modeling predicts considerable inhomogeneities of cloud cover, consistent with optical phase curve observations. However, optical phase curves cannot resolve some existing degeneracies between cloud location and cloud optical properties. We present a conceptually simple technique to detect inhomogeneous cloud cover on exoplanets. Such an inhomogeneous cloud cover produces an asymmetric primary transit of the planet in front of the host star. Asymmetric transits produce characteristic residuals compared to a standard symmetric model. Furthermore, bisector spans can be used to determine asymmetries in the transit light curve. We apply a model of asymmetric transits to the light curves of HAT-P-7b, Kepler-7b and HD209458b and search for possible cloud signatures. The nearly uninterrupted Kepler photometry is particularly well-suited for this method since it allows for a very high time resolution. We do not find any statistical...
Relative Composition and Energy Spectra of Light Nuclei in Cosmic Rays: Results from AMS-01
Aguilar, M.; Alcaraz, J.; Allaby, J.; Alpat, B.; Ambrosi, G.; Anderhub, H.; Ao, L.; Arefiev, A.; Arruda, L.; Azzarello, P.; Basile, M.; Barao, F.; Barreira, G.; Bartoloni, A.; Battiston, R.; Becker, R.; Becker, U.; Bellagamba, L.; Béné, P.; Berdugo, J.; Berges, P.; Bertucci, B.; Biland, A.; Bindi, V.; Boella, G.; Boschini, M.; Bourquin, M.; Bruni, G.; Buénerd, M.; Burger, J. D.; Burger, W. J.; Cai, X. D.; Cannarsa, P.; Capell, M.; Casadei, D.; Casaus, J.; Castellini, G.; Cernuda, I.; Chang, Y. H.; Chen, H. F.; Chen, H. S.; Chen, Z. G.; Chernoplekov, N. A.; Chiueh, T. H.; Choi, Y. Y.; Cindolo, F.; Commichau, V.; Contin, A.; Cortina-Gil, E.; Crespo, D.; Cristinziani, M.; Dai, T. S.; dela Guia, C.; Delgado, C.; Di Falco, S.; Djambazov, L.; D'Antone, I.; Dong, Z. R.; Duranti, M.; Engelberg, J.; Eppling, F. J.; Eronen, T.; Extermann, P.; Favier, J.; Fiandrini, E.; Fisher, P. H.; Flügge, G.; Fouque, N.; Galaktionov, Y.; Gervasi, M.; Giovacchini, F.; Giusti, P.; Grandi, D.; Grimm, O.; Gu, W. Q.; Haino, S.; Hangarter, K.; Hasan, A.; Hermel, V.; Hofer, H.; Hungerford, W.; Ionica, M.; Jongmanns, M.; Karlamaa, K.; Karpinski, W.; Kenney, G.; Kim, D. H.; Kim, G. N.; Kim, K. S.; Kirn, T.; Klimentov, A.; Kossakowski, R.; Kounine, A.; Koutsenko, V.; Kraeber, M.; Laborie, G.; Laitinen, T.; Lamanna, G.; Laurenti, G.; Lebedev, A.; Lechanoine-Leluc, C.; Lee, M. W.; Lee, S. C.; Levi, G.; Lin, C. H.; Liu, H. T.; Lu, G.; Lu, Y. S.; Lübelsmeyer, K.; Luckey, D.; Lustermann, W.; Maña, C.; Margotti, A.; Mayet, F.; McNeil, R. R.; Menichelli, M.; Mihul, A.; Mujunen, A.; Oliva, A.; Palmonari, F.; Park, H. B.; Park, W. H.; Pauluzzi, M.; Pauss, F.; Pereira, R.; Perrin, E.; Pevsner, A.; Pilo, F.; Pimenta, M.; Plyaskin, V.; Pojidaev, V.; Pohl, M.; Produit, N.; Quadrani, L.; Rancoita, P. G.; Rapin, D.; Ren, D.; Ren, Z.; Ribordy, M.; Richeux, J. P.; Riihonen, E.; Ritakari, J.; Ro, S.; Roeser, U.; Sagdeev, R.; Santos, D.; Sartorelli, G.; Sbarra, C.; Schael, S.; Schultz von Dratzig, A.; Schwering, G.; Seo, E. S.; Shin, J. W.; Shoumilov, E.; Shoutko, V.; Siedenburg, T.; Siedling, R.; Son, D.; Song, T.; Spada, F. R.; Spinella, F.; Steuer, M.; Sun, G. S.; Suter, H.; Tang, X. W.; Ting, Samuel C. C.; Ting, S. M.; Tomassetti, N.; Tornikoski, M.; Torsti, J.; Trümper, J.; Ulbricht, J.; Urpo, S.; Valtonen, E.; Vandenhirtz, J.; Velikhov, E.; Verlaat, B.; Vetlitsky, I.; Vezzu, F.; Vialle, J. P.; Viertel, G.; Vité, D.; Von Gunten, H.; Waldmeier Wicki, S.; Wallraff, W.; Wang, J. Z.; Wiik, K.; Williams, C.; Wu, S. X.; Xia, P. C.; Xu, S.; Xu, Z. Z.; Yan, J. L.; Yan, L. G.; Yang, C. G.; Yang, J.; Yang, M.; Ye, S. W.; Zhang, H. Y.; Zhang, Z. P.; Zhao, D. X.; Zhou, F.; Zhou, Y.; Zhu, G. Y.; Zhu, W. Z.; Zhuang, H. L.; Zichichi, A.; Zimmermann, B.; Zuccon, P.
2010-11-01
Measurement of the chemical and isotopic composition of cosmic rays is essential for the precise understanding of their propagation in the galaxy. While the model parameters are mainly determined using the B/C ratio, the study of extended sets of ratios can provide stronger constraints on the propagation models. In this paper, the relative abundances of light-nuclei lithium, beryllium, boron, and carbon are presented. The secondary-to-primary ratios Li/C, Be/C, and B/C have been measured in the kinetic energy range 0.35-45 GeV nucleon-1. The isotopic ratio 7Li/6Li is also determined in the magnetic rigidity interval 2.5-6.3 GV. The secondary-to-secondary ratios Li/Be, Li/B, and Be/B are also reported. These measurements are based on the data collected by the Alpha Magnetic Spectrometer AMS-01 during the STS-91 space shuttle flight in 1998 June. Our experimental results are in substantial agreement with other measurements, where they exist. We describe our light-nuclei data with a diffusive-reacceleration model. A 10%-15% overproduction of Be is found in the model predictions and can be attributed to uncertainties in the production cross-section data.
Relative Composition and Energy Spectra of Light Nuclei in Cosmic Rays. Results from AMS-01
Aguilar, M; Allaby, J; Alpat, B; Ambrosi, G; Anderhub, H; Ao, L; Arefiev, A; Arruda, L; Azzarello, P; Basile, M; Barao, F; Barreira, G; Vartoloni, A; Battiston, R; Becker, R; Becker, U; Bellagamba, L; Bene, P; Berdugo, J; Berges, P; Bertucci, B; Biland, A; Bindi, V; Boella, G; Boschini, M; Bourquin, M; Bruni, G; Buenerd, M; Burger, J D; Burger, W J; Cai, X D; Cannarsa, P; Capell, M; Casadei, D; Casaus, J; Castellini, G; Cernuda, I; Chang, Y H; Chen, H F; Chen, H S; Chen, Z G; Chernoplekov, N A; Chiueh, T H; Choi, Y Y; Cindolo, F; Commichau, V; Contin, A; Cortina-Gil, E; Crespo, D; Cristinziani, M; Dai, T S; Dela Guia, C; Delgado, C; Di Falco, S; Djambazov, L; D'Antoine, I; Dong, Z R; Duranti, M; Engelberg, J; Eppling, F J; Eronen, T; Extermann, P; Favier, J; Fiandrini, E; Fisher, P H; Flugge, G; Fouque, N; Galaktionov, Y; Gervasi, M; Giovacchini, F; Giusti, P; Grandi, D; Grimm, O; Gu, W Q; Haino, S; Hangarter, K; Hasan, A; Hermel, V; Hofer, H; Hungerford, W; Ionica, M; Jongmanns, M; Karlamaa, K; Karpinski, W; Kenney, G; Kim, D H; Kim, G N; Kim, K S; Kirn, T; Klimentov, A; Kossakowski, R; Kounine, A; Koutsenko, V; Kraeber, M; Laborie, G; Laitinen, T; Lamanna, G; Laurenti, G; Lebedev, A; Lechanoine-Leluc, C; Lee, M W; Lee, S C; Levi, G; Lin, C H; Liu, H T; Lu, G; Lubelsmeyer, K; Luckey, D; Lustermann, W; Mana, C; Margotti, A; Mayet, F; McNeil, R R; Menichelli, M; Mihul, A; Mujunen, A; Oliva, A; Palmonari, F; Park, H B; Park, W H; Pauluzzi, M; Pauss, F; Pereira, R; Perrin, E; Pevsner, A; Pilo, F; Pimenta, M; Plyaskin, V; Pojidaev, V; Pohl, M; Produit, N; Quadrani, L; Rancoita, P G; Rapin, D; Ren, D; Ren, Z; Ribordy, M; Richeux, J P; Riihonen, E; Ritakari, J; Ro, S; Roeser, U; Sagdeev, R; Santos, D; Sartorelli, G; Sbarra, C; Schael, S; Schultz von Dratzig, A; Schwering, G; Seo, E S; Shin, J W; Shoumilov, E; Shoutko, V; Siedenburg, T; Siedling, R; Son, D; Song, T; Spada, F R; Spinella, F; Steuer, M; Sun, G S; Suter, H; Tang, X W; Ting, Samuel C C; Ting, S M; Tomassetti, N; Tornikoski, M; Torsti, J; Trumper, J; Ulbricht, J; Urpo, S; Valtonen, E; Vandenhirtz, J; Velikhov, E; Verlaat, B; Vetlitsky, I; Vezzu, F; Vialle, J P; Viertel, G; Vite, D; Von Gunten, H; Waldmeier Wicki, S; Wallraff, W; Wang, J Z; Wiik, K; Williams, C; Wu, S X; Xia, P C; Xu, S; Xu, Z Z; Yan, J L; Yan, L G; Yang, C G; Yang, J; Yang, M; Ye, S W; Zhang, H Y; Zhang, Z P; Zhao, D X; Zhou, F; Zhou, Y; Zhu, G Y; Zhu, W Z; Zhuang, H L; Zichichi, A; Zimmermann, B; Zuccon, P
2010-01-01
Measurement of the chemical and isotopic composition of cosmic rays is essential for the precise understanding of their propagation in the galaxy. While the model parameters are mainly determined using the B/C ratio, the study of extended sets of ratios can provide stronger constraints on the propagation models. In this paper the relative abundances of the light nuclei lithium, beryllium, boron and carbon are presented. The secondary to primary ratios Li/C, Be/C and B/C have been measured in the kinetic energy range 0.35-45 GeV/nucleon. The isotopic ratio 7Li/6Li is also determined in the magnetic rigidity interval 2.5-6.3 GV. The secondary to secondary ratios Li/Be, Li/B and Be/B are also reported. These measurements are based on the data collected by the Alpha Magnetic Spectrometer AMS-01 during the STS-91 space shuttle flight in 1998 June. Our experimental results are in substantial agreement with other measurements, where they exist. We describe our light-nuclei data with a diffusive-reacceleration model....
MCNP6 Simulation of Light and Medium Nuclei Fragmentation at Intermediate Energies
Energy Technology Data Exchange (ETDEWEB)
Mashnik, Stepan Georgievich [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kerby, Leslie Marie [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2015-05-22
MCNP6, the latest and most advanced LANL Monte Carlo transport code, representing a merger of MCNP5 and MCNPX, is actually much more than the sum of those two computer codes; MCNP6 is available to the public via RSICC at Oak Ridge, TN, USA. In the present work, MCNP6 was validated and verified (V&V) against different experimental data on intermediate-energy fragmentation reactions, and results by several other codes, using mainly the latest modifications of the Cascade-Exciton Model (CEM) and of the Los Alamos version of the Quark-Gluon String Model (LAQGSM) event generators CEM03.03 and LAQGSM03.03. It was found that MCNP6 using CEM03.03 and LAQGSM03.03 describes well fragmentation reactions induced on light and medium target nuclei by protons and light nuclei of energies around 1 GeV/nucleon and below, and can serve as a reliable simulation tool for different applications, like cosmic-ray-induced single event upsets (SEU’s), radiation protection, and cancer therapy with proton and ion beams, to name just a few. Future improvements of the predicting capabilities of MCNP6 for such reactions are possible, and are discussed in this work.
Freeze-out conditions for production of resonances, hadronic molecules, and light nuclei
Cho, Sungtae; Lee, Su Houng
2015-01-01
We investigate the freeze-out conditions of a particle in an expanding system of interacting particles in order to understand the productions of resonances, hadronic molecules and light nuclei in heavy ion collisions. Applying the kinetic freeze-out condition with explicit hydrodynamic calculations for the expanding hadronic phase to the daughter particles of $K^*$ mesons, we find that the larger suppression of the yield ratio of $K^*/K$ at LHC than at RHIC compared to the expectations from the statistical hadronization model based on chemical freeze-out parameters reflects the lower kinetic freeze-out temperature at LHC than at RHIC. Furthermore, we point out that for the light nuclei or hadronic molecules that are bound, the yields are affected by the freeze-out condition of the respective particle in the hadronic matter, which leads to the observation that the deuteron production yields are independent of the size of deuteron, and depend only on the number of ground state constituents.
Directory of Open Access Journals (Sweden)
Kirsch Lee E
2008-07-01
Full Text Available Abstract Background Glucagon is a peptide hormone with many uses as a therapeutic agent, including the emergency treatment of hypoglycemia. Physical instability of glucagon in solution leads to problems with the manufacture, formulation, and delivery of this pharmaceutical product. Glucagon has been shown to aggregate and form fibrils and gels in vitro. Small oligomeric precursors serve to initiate and nucleate the aggregation process. In this study, these initial aggregates, or seed nuclei, are characterized in bulk solution using light scattering methods and field-flow fractionation. Results High molecular weight aggregates of glucagon were detected in otherwise monomeric solutions using light scattering techniques. These aggregates were detected upon initial mixing of glucagon powder in dilute HCl and NaOH. In the pharmaceutically relevant case of acidic glucagon, the removal of aggregates by filtration significantly slowed the aggregation process. Field-flow fractionation was used to separate aggregates from monomeric glucagon and determine relative mass. The molar mass of the large aggregates was shown to grow appreciably over time as the glucagon solutions gelled. Conclusion The results of this study indicate that initial glucagon solutions are predominantly monomeric, but contain small quantities of large aggregates. These results suggest that the initial aggregates are seed nuclei, or intermediates which catalyze the aggregation process, even at low concentrations.
Do light nuclei display a universal γ-ray strength function?
Directory of Open Access Journals (Sweden)
Voinov A.
2012-02-01
Full Text Available In this work we focus on properties in the quasi-continuum of light nuclei. Generally, both level density and γ-ray strength function (γ-SF differ from nucleus to nucleus. In order to investigate this closer, we have performed particle-γ coincidences using the reactions (p, p', (p, d and (p, t on a 46Ti target. In particular, the very rich data set of the 46Ti(p, p'46Ti inelastic scattering reaction allows analysis of the coincidence data for many independent data sets. Using the Oslo method, we find one common level density for all data sets. If transitions to well-separated low-energy levels are included, the deduced γ-SF may change by a factor of 2 – 3, due strong to Porter-Thomas fluctuations. However, a universal γ-SF with small fluctuations is found provided that only excitation energies above 3 MeV are taken into account. The nuclear structure of the titaniums is discussed within a combinatorial quasi-particle model, showing that only few Nilsson orbitals participate in building up the level density for these light nuclei.
Inferring asymmetric limb cloudiness on exoplanets from transit light curves
von Paris, P.; Gratier, P.; Bordé, P.; Leconte, J.; Selsis, F.
2016-05-01
Context. Clouds have been shown to be present in many exoplanetary atmospheres. Cloud formation modeling predicts considerable inhomogeneities of cloud cover, consistent with optical phase curve observations. However, optical phase curves cannot resolve some existing degeneracies between cloud location and cloud optical properties. Aims: We present a conceptually simple technique for detecting inhomogeneous cloud cover on exoplanets. Such an inhomogeneous cloud cover produces an asymmetric primary transit of the planet in front of the host star. Asymmetric transits produce characteristic residuals that are different from standard symmetric models. Furthermore, bisector spans can be used to determine asymmetries in the transit light curve. Methods: We apply a model of asymmetric transits to the light curves of HAT-P-7b, Kepler-7b, and HD 209458b and search for possible cloud signatures. The nearly uninterrupted Kepler photometry is particularly well suited for this method since it allows for a very high time resolution. Results: We do not find any statistically sound cloud signature in the data of the considered planets. For HAT-P-7b, a tentative detection of an asymmetric cloud cover is found, consistent with analysis of the optical phase curve. Based on Bayesian probability arguments, a symmetric model with an offset in the transit ephemeris is still the most viable model. This work demonstrates that for suitable targets, namely low-gravity planets around bright stars, the method can be used to constrain cloud cover characteristics and is thus a helpful additional tool for the study of exoplanetary atmospheres.
Furusawa, Shun; Yamada, Shoichi; Suzuki, Hideyuki
2013-01-01
We construct new equations of state for baryons at sub-nuclear densities for the use in core-collapse simulations of massive stars. The abundance of various nuclei is obtained together with thermodynamic quantities. A model free energy is constructed, based on the relativistic mean field theory for nucleons and the mass formula for nuclei with the proton number up to ~ 1000. The formulation is an extension of the previous model, in which we adopted the liquid drop model to all nuclei under the nuclear statistical equilibrium. We reformulate the new liquid drop model so that the temperature dependences of bulk energies could be taken into account. Furthermore, we extend the region in the nuclear chart, in which shell affects are included, by using theoretical mass data in addition to experimental ones. We also adopt a quantum theoretical mass evaluation of light nuclei, which incorporates the Pauli- and self-energy shifts that are not included in the ordinary liquid drop model. The pasta phases for heavy nucle...
Light Nuclei in the Framework of the Symplectic No-Core Shell Model
Energy Technology Data Exchange (ETDEWEB)
Draayer, Jerry P.; Dytrych, Tomas; Sviratcheva, Kristina D.; Bahri, Chairul; /Louisiana State U.; Vary, James P.; /Iowa State U. /LLNL, Livermore /SLAC
2007-04-02
A symplectic no-core shell model (Sp-NCSM) is constructed with the goal of extending the ab-initio NCSM to include strongly deformed higher-oscillator-shell configurations and to reach heavier nuclei that cannot be studied currently because the spaces encountered are too large to handle, even with the best of modern-day computers. This goal is achieved by integrating two powerful concepts: the ab-initio NCSM with that of the Sp(3,R) {contains} SU(3) group-theoretical approach. The NCSM uses modern realistic nuclear interactions in model spaces that consists of many-body configurations up to a given number of {h_bar}{Upsilon} excitations together with modern high-performance parallel computing techniques. The symplectic theory extends this picture by recognizing that when deformed configurations dominate, which they often do, the model space can be better selected so less relevant low-lying {h_bar}{Upsilon} configurations yield to more relevant high-lying {h_bar}{Upsilon} configurations, ones that respect a near symplectic symmetry found in the Hamiltonian. Results from an application of the Sp-NCSM to light nuclei are compared with those for the NCSM and with experiment.
Ab-initio Hamiltonian approach to light nuclei and to quantum field theory
Indian Academy of Sciences (India)
J P Vary; H Honkanen; Jun Li; P Maris; A M Shirokov; S J Brodsky; A Harindranath; G F De Teramond; E G Ng; C Yang; M Sosonkina
2010-07-01
Nuclear structure physics is on the threshold of confronting several long-standing problems such as the origin of shell structure from basic nucleon–nucleon and three-nucleon interactions. At the same time those interactions are being developed with increasing contact to QCD, the underlying theory of the strong interactions, using effective field theory. The motivation is clear – QCD offers the promise of great predictive power spanning phenomena on multiple scales from quarks and gluons to nuclear structure. However, new tools that involve non-perturbative methods are required to build bridges from one scale to the next. We present an overview of recent theoretical and computational progress with a Hamiltonian approach to build these bridges and provide illustrative results for the nuclear structure of light nuclei and quantum field theory.
Light Nuclei and Hypernuclei from Quantum Chromodynamics in the Limit of SU(3) Flavor Symmetry
Beane, S R; Cohen, S D; Detmold, W; Lin, H W; Luu, T C; Orginos, K; Parreno, A; Savage, M J; Walker-Loud, A
2012-01-01
The binding energies of a range of nuclei and hypernuclei with atomic number A <= 4 and strangeness |s| <= 2, including the deuteron, di-neutron, H-dibaryon, 3He, Lambda 3He, Lambda 4He, and Lambda Lambda 4He, are calculated in the limit of flavor-SU(3) symmetry at the physical strange quark mass with quantum chromodynamics (without electromagnetic interactions). The nuclear states are extracted from Lattice QCD calculations performed with n_f=3 dynamical light quarks using an isotropic clover discretization of the quark-action in three lattice volumes of spatial extent L ~ 3.4 fm, 4.5 fm and 6.7 fm, and with a single lattice spacing b ~ 0.145 fm.
Exotic Properties of Light Nuclei and their Neutron Capture Cross Sections
Mengoni, A; Nakamura, T; Ishihara, M
1996-01-01
We have investigated the implications of the neutron halo configuration, observed in the ground-state of some neutron-rich light nuclei, on neutron radiative transition processes. In particular, we have studied the influence of the neutron halo on the direct radiative capture (DRC) process. The energy dependence as well as the strength of E1 emission due to incident p-wave neutrons is strongly influenced by the halo configuration of the residual nucleus capturing state. We have compared the calculated 10Be(n,gamma)11Be DRC cross section with that derived from the experiment in the inverse kinematics (Coulomb dissociation of 11Be). We show from the comparison that some important information on the structure of the halo nucleus 11Be can be derived.
Finite nuclei in relativistic models with a light chiral scalar meson
Furnstahl, R. J.; Serot, Brian D.
1993-05-01
Relativistic chiral models with a light scalar meson appear to provide an economical marriage of successful relativistic mean-field theories and chiral symmetry. The scalar meson serves as both the chiral partner of the pion and the mediator of the intermediate-range nucleon-nucleon (NN) attraction. However, while some of these models can reproduce the empirical nuclear matter saturation point, they fail to reproduce observed properties of finite nuclei, such as spin-orbit splittings, shell structure, charge densities, and surface energetics. These deficiencies imply that this realization of chiral symmetry is incorrect. An alternative scenario, which features a heavy chiral scalar and dynamical generation of the NN attraction, is discussed.
Chiral Three-Nucleon Interactions in Light Nuclei, Neutron-$\\alpha$ Scattering, and Neutron Matter
Lynn, J E; Carlson, J; Gandolfi, S; Gezerlis, A; Schmidt, K E; Schwenk, A
2015-01-01
We present quantum Monte Carlo calculations of light nuclei, neutron-$\\alpha$ scattering, and neutron matter using local two- and three-nucleon (3N) interactions derived from chiral effective field theory up to next-to-next-to-leading order (N$^2$LO). The two undetermined 3N low-energy couplings are fit to the $^4$He binding energy and, for the first time, to the spin-orbit splitting in the neutron-$\\alpha$ $P$-wave phase shifts. Furthermore, we investigate different choices of local 3N operator structures and find that chiral interactions at N$^2$LO are able to simultaneously reproduce the properties of $A=4,5$ systems and of neutron matter, in contrast to commonly used phenomenological 3N interactions.
Gamma ray astronomy and the origin of the light nuclei. [cosmic ray and interstellar gas reactions
Reeves, H.
1978-01-01
Nuclear reactions induced by the collisions of the protons and alphas of the galactic cosmic ray with heavy nuclei of the interstellar gas are responsible for the continuous production of the light elements lithium, beryllium, and boron in the galaxy. To better than one order of magnitude, the observed ratios of these abundances to hydrogen abundance and the nuclidic abundance ratios between themselves are accounted for by simply considering the effect of fast protons and alphas with a flux and an energy spectrum as observed in galactic cosmic rays, for a period comparable with the life of our galaxy. The role of gamma ray astronomy in solving problems that occur when accurate agreement is sought with increasingly accurate data is discussed.
Toroidal high-spin isomers in light nuclei with N not equal to Z
Staszczak, Andrzej
2014-01-01
The combined considerations of both the bulk liquid-drop-type behavior and the quantized aligned rotation with cranked Skyrme-Hartree-Fock approach revealed previously that even-even, N=Z, toroidal high-spin isomeric states have general occurrences for light nuclei with A between 28 and 52. We find that in this mass region there are in addition N not equal to Z toroidal high-spin isomers when the single-particle shells for neutrons and protons occur at the same cranked frequency $\\hbar \\omega$. Examples of N not equal to Z toroidal high-spin isomers, $^{36}_{16}$S$_{20}$($I$=74$\\hbar$) and $^{40}_{18}$Ar$_{22}$($I$=80,102$\\hbar$), are located and examined. The systematic properties of these N not equal to Z toroidal high-spin isomers fall into the same regular (muti-particle)-(muti-hole) patterns as other N=Z toroidal high-spin isomers.
The muon-positron conversion in nuclei mediated by light Majorana neutrinos
Simkovic, F; Kovalenko, S V; Faessler, A; Faessler, Amand
2001-01-01
We study the lepton number violating muon-positron conversion in nuclei mediated by the exchange of virtual light Majorana neutrinos. We found that a previously overlooked imaginary part of this amplitude plays an important role. The numerical calculation has been made for the experimentally interesting muon-positron conversion in Ti48 using realistic renormalized proton-neutron QRPA wave functions. We also discuss the very similar case of the neutrinoless double beta decay of Ca48 The ratio of muon-positron conversion over the total muon absorption has been computed taking into account the current constraints from neutrino oscillation phenomenology. We compare our results with the experimental limits as well as with previous theoretical predictions. We have found that the Majorana neutrino mode of muon-positron conversion in Ti48 is too small to be measurable in the foreseeable future.
Collectivity in the light radon nuclei measured directly via Coulomb excitation
Gaffney, L P; Jenkins, D G; Andreyev, A N; Bender, M; Blazhev, A; Bree, N; Bruyneel, B; Butler, P A; Cocolios, T E; Davinson, T; Deacon, A N; De Witte, H; DiJulio, D; Diriken, J; Ekström, A; Fransen, Ch; Freeman, S J; Geibel, K; Grahn, T; Hadinia, B; Hass, M; Heenen, P -H; Hess, H; Huyse, M; Jakobsson, U; Kesteloot, N; Konki, J; Kröll, Th; Kumar, V; Ivanov, O; Martin-Haugh, S; Mücher, D; Orlandi, R; Pakarinen, J; Petts, A; Peura, P; Rahkila, P; Reiter, P; Scheck, M; Seidlitz, M; Singh, K; Smith, J F; Van de Walle, J; Van Duppen, P; Voulot, D; Wadsworth, R; Warr, N; Wenander, F; Wimmer, K; Wrzosek-Lipska, K; Zielińska, M
2015-01-01
Background: Shape coexistence in heavy nuclei poses a strong challenge to state-of-the-art nuclear models, where several competing shape minima are found close to the ground state. A classic region for investigating this phenomenon is in the region around $Z=82$ and the neutron mid-shell at $N=104$. Purpose: Evidence for shape coexistence has been inferred from $\\alpha$-decay measurements, laser spectroscopy and in-beam measurements. While the latter allow the pattern of excited states and rotational band structures to be mapped out, a detailed understanding of shape coexistence can only come from measurements of electromagnetic matrix elements. Method: Secondary, radioactive ion beams of $^{202}$Rn and $^{204}$Rn were studied by means of low-energy Coulomb excitation at the REX-ISOLDE facility in CERN. Results: The electric-quadrupole ($E2$) matrix element connecting the ground state and first-excited $2^{+}_{1}$ state was extracted for both $^{202}$Rn and $^{204}$Rn, corresponding to ${B(E2;2^{+}_{1} \\to 2^...
Alpha cluster states in light nuclei populated through the (6Li,d) reaction
Energy Technology Data Exchange (ETDEWEB)
Borello-Lewin, Thereza; Rodrigues, M.R.D.; Horodynski-Matsushigue, L.B.; Duarte, J.L.M.; Rodrigues, C.L.; Souza, M.A. [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica; Cunsolo, A.; Cappuzzello, F. [Universita di Catania (Italy). Istituto Nazionale di Fisica Nucleare. Lab. Nazionali del Sud; Ukita, Gilberto Mitsuo [Universidade de Santo Amaro (UNISA), Sao Paulo, SP (Brazil). Fac. de Psicologia
2011-07-01
Full text: The alpha cluster correlation is an important concept in the nuclear physics of light nuclei. The main purpose of the research program in progress is the investigation of the alpha clustering phenomenon in (x{alpha}) and(x{alpha}+{nu}) nuclei through the ({sup 6}Li,d) alpha transfer reaction. In fact, there is scarce experimental information on the subject, in particular associated with resonant states predicted near (x{alpha}) and (x{alpha}+{nu}) thresholds. Measurements of the {sup 12},{sup 13}C({sup 6}Li,d) {sup 16},{sup 17}O reactions, at an incident energy of 25.5 MeV, have been performed employing the Sao Paulo Pelletron-Enge Split-Pole facility and the nuclear emulsion detection technique. The work is under way and an experimental energy resolution of 30 keV was obtained. Near the (4{alpha}) breakup threshold in {sup 16}O, three narrow alpha resonances, not previously measured, were detected, revealing important {alpha} + {sup 12}C(G.S.) components. One of these resonances corresponds to the known 0{sup +} state at 15.1 MeV[5] of excitation that has probably, according to Funaki et al., the gas like configuration of the 4{alpha} condensate state, with a very dilute density and a large component of {alpha} + {sup 12}C(Hoyle) configuration. As was already mentioned, our experimental information points to the necessity of including the {alpha} + {sup 12}C(G.S.) component in the wave function. (author)
Electric dipole moments of light nuclei in chiral effective field theory
Energy Technology Data Exchange (ETDEWEB)
Bsaisou, Jan
2014-04-25
Dimensional Analysis (NDA) estimates of the coupling constants. These estimates prove to be sufficient to reveal certain hierarchies of coupling constants. The different hierarchies of coupling constants translate into different hierarchies of the nuclear contributions to the EDMs of light nuclei. We calculate within the framework of ChPT the two-nucleon contributions to the EDM of the deuteron up to and including next-to-next-to leading order and the two-nucleon contributions to the EDMs of the helion ({sup 3}He nucleus) and the triton ({sup 3}H nucleus) up to and including next-to-leading order. These computations comprise thorough investigations of the uncertainties of the results from the P- and T-violating component as well as the P- and T-conserving component of the nuclear potential. We present quantitative predictions of the nuclear contributions to the EDMs of the deuteron, the helion and the triton induced by the QCD θ-term as functions of anti θ with well-defined uncertainties. The EDM predictions for the effective dimension-six sources are given as function of the yet unknown LECs with NDA estimates. We present several strategies to falsify the QCD θ-term as a relevant source of P and T violation by a suitable combination of measurements of several light nuclei and, if needed, supplementary lattice QCD input. If the QCD θ-term fails these tests, one or several of the effective dimension-six sources encoding physics beyond the Standard Model are most likely the source(s) of P and T violation. We demonstrate how particular effective dimension-six sources can be tested by EDM measurements of light nuclei with eventually supplementary Lattice QCD input.
Measuring the fusion cross-section of light nuclei with low-intensity beams
Energy Technology Data Exchange (ETDEWEB)
Steinbach, T.K.; Rudolph, M.J.; Gosser, Z.Q.; Brown, K.; Floyd, B.; Hudan, S. [Department of Chemistry and Center for Exploration of Energy and Matter, Indiana University, 2401 Milo B. Sampson Lane, Bloomington, IN 47408 (United States); Souza, R.T. de, E-mail: desouza@indiana.edu [Department of Chemistry and Center for Exploration of Energy and Matter, Indiana University, 2401 Milo B. Sampson Lane, Bloomington, IN 47408 (United States); Liang, J.F.; Shapira, D. [Oak Ridge National Laboratory, Physics Division, Oak Ridge, TN 37831 (United States); Famiano, M. [Department of Physics, Western Michigan University, Kalamazoo, MI 49008 (United States)
2014-04-11
We demonstrate an approach to measure the total fusion cross-section for beams of low-intensity light nuclei. Fusion residues resulting from the fusion of {sup 20,16}O+{sup 12}C are directly measured and distinguished from unreacted beam particles on the basis of their energy and time-of-flight. The time-of-flight is measured between a microchannel plate (MCP) detector, which serves as a start, and a segmented silicon detector, which provides a stop. The two main difficulties associated with the initial implementation of this approach are charge trapping in the silicon detector and slit scattering in the MCP detector. Both these obstacles have been characterized and overcome. To reduce atomic slit scattering in the measurement we have eliminated wires from the beam path by developing a gridless MCP detector. The total fusion cross-section for {sup 16}O+{sup 12}C in the energy range E{sub CM}=8.0–12.0 MeV has been measured in agreement with established literature values (down to the 100 mb level)
Nuclear matter saturation with chiral three-nucleon interactions fitted to light nuclei properties
Energy Technology Data Exchange (ETDEWEB)
Logoteta, Domenico [INFN, Sezione di Pisa, Largo Bruno Pontecorvo 3, I-56127 Pisa (Italy); Bombaci, Ignazio, E-mail: ignazio.bombaci@unipi.it [Dipartimento di Fisica, Universitá di Pisa, Largo Bruno Pontecorvo 3, I-56127 Pisa (Italy); INFN, Sezione di Pisa, Largo Bruno Pontecorvo 3, I-56127 Pisa (Italy); European Gravitational Observatory, Via E. Amaldi, I-56021 S. Stefano a Macerata, Cascina (Italy); Kievsky, Alejandro [INFN, Sezione di Pisa, Largo Bruno Pontecorvo 3, I-56127 Pisa (Italy)
2016-07-10
The energy per particle of symmetric nuclear matter and pure neutron matter is calculated using the many-body Brueckner–Hartree–Fock approach and employing the Chiral Next-to-next-to-next-to leading order (N3LO) nucleon–nucleon (NN) potential, supplemented with various parametrizations of the Chiral Next-to-next-to leading order (N2LO) three-nucleon interaction. Such combination is able to reproduce several observables of the physics of light nuclei for suitable choices of the parameters entering in the three-nucleon interaction. We find that some of these parametrizations provide a satisfactory saturation point of symmetric nuclear matter and values of the symmetry energy and its slope parameter L in very good agreement with those extracted from various nuclear experimental data. Thus, our results represent a significant step toward a unified description of few- and many-body nuclear systems starting from two- and three-nucleon interactions based on the symmetries of QCD.
Thermal properties of light nuclei from 12C + 12C fusion-evaporation reactions
Morelli, L.; Baiocco, G.; D'Agostino, M.; Gulminelli, F.; Bruno, M.; Abbondanno, U.; Appannababu, S.; Barlini, S.; Bini, M.; Casini, G.; Cinausero, M.; Degerlier, M.; Fabris, D.; Gelli, N.; Gramegna, F.; Kravchuk, V. L.; Marchi, T.; Olmi, A.; Pasquali, G.; Piantelli, S.; Valdré, S.; Raduta, Ad R.
2014-07-01
The 12C + 12C reaction at 95 MeV has been studied through the complete charge identification of its products by means of the GARFIELD+RCo experimental set-up at INFN Laboratori Nazionali di Legnaro (LNL). In this paper, the first of a series of two, a comparison to a dedicated Hauser-Feshbach calculation allows selecting a set of dissipative events which corresponds, to a large extent, to the statistical evaporation of highly excited 24Mg. Information on the isotopic distribution of the evaporation residues in coincidence with their complete evaporation chain is also extracted. The set of data puts strong constraints on the behaviour of the level density (LD) of light nuclei above the threshold for particle emission. In particular, a fast increase of the LD parameter with excitation energy is supported by the data. Residual deviations from a statistical behaviour are seen in two specific channels, and tentatively associated with a contamination from direct reactions and/or α-clustering effects. These channels are studied in further details in the second paper of the series.
Quantal self-consistent cranking model for monopole excitations in even-even light nuclei
Gulshani, P
2014-01-01
In this article, we derive a quantal self-consistent time-reversal invariant cranking model for isoscalar monopole excitation coupled to intrinsic motion in even-even light nuclei. The model uses a wavefunction that is a product of monopole and intrinsic wavefunctions and a constrained variational method to derive, from a many-particle Schrodinger equation, a pair of coupled self-consistent cranking-type Schrodinger equations for the monopole and intrinsic systems. The monopole and intrinsic wavefunctions are coupled to each other by the two cranking equations and their associated parameters and by two constraints imposed on the intrinsic system. For an isotropic Nilsson shell model and an effective residual two-body interaction, the two coupled cranking equations are solved in the Tamm Dancoff approximation. The strength of the interaction is determined from a Hartree-Fock self-consistency argument. The excitation energy of the first excited state is determined and found to agree closely with those observed ...
Nuclear matter saturation with chiral three-nucleon interactions fitted to light nuclei properties
Logoteta, Domenico; Bombaci, Ignazio; Kievsky, Alejandro
2016-07-01
The energy per particle of symmetric nuclear matter and pure neutron matter is calculated using the many-body Brueckner-Hartree-Fock approach and employing the Chiral Next-to-next-to-next-to leading order (N3LO) nucleon-nucleon (NN) potential, supplemented with various parametrizations of the Chiral Next-to-next-to leading order (N2LO) three-nucleon interaction. Such combination is able to reproduce several observables of the physics of light nuclei for suitable choices of the parameters entering in the three-nucleon interaction. We find that some of these parametrizations provide a satisfactory saturation point of symmetric nuclear matter and values of the symmetry energy and its slope parameter L in very good agreement with those extracted from various nuclear experimental data. Thus, our results represent a significant step toward a unified description of few- and many-body nuclear systems starting from two- and three-nucleon interactions based on the symmetries of QCD.
Thermal properties of light nuclei from $^{12}$C+$^{12}$C fusion-evaporation reactions
Morelli, L; D'Agostino, M; Gulminelli, F; Bruno, M; Abbondanno, U; Appannababu, S; Barlini, S; Bini, M; Casini, G; Cinausero, M; Degerlier, M; Fabris, D; Gelli, N; Gramegna, F; Kravchuk, V L; Marchi, T; Pasquali, G; Piantelli, S; Valdré, S; Raduta, Ad R
2014-01-01
The $^{12}$C+$^{12}$C reaction at 95 MeV has been studied through the complete charge identification of its products by means of the GARFIELD+RCo experimental set-up at INFN Laboratori Nazionali di Legnaro (LNL). In this paper, the first of a series of two, a comparison to a dedicated Hauser-Feshbach calculation allows to select a set of dissipative events which corresponds, to a large extent, to the statistical evaporation of highly excited $^{24}$Mg. Information on the isotopic distribution of the evaporation residues in coincidence with their complete evaporation chain is also extracted. The set of data puts strong constraints on the behaviour of the level density of light nuclei above the threshold for particle emission. In particular, a fast increase of the level density parameter with excitation energy is supported by the data. Residual deviations from a statistical behaviour are seen in two specific channels, and tentatively associated with a contamination from direct reactions and/or $\\alpha$-clusteri...
Fermi-LAT high-z active galactic nuclei and the extragalactic background light
Armstrong, Thomas; Brown, Anthony M.; Chadwick, Paula M.
2017-10-01
Observations of distant gamma-ray sources are hindered by the presence of the extragalactic background light (EBL). In order to understand the physical processes that result in the observed spectrum of sources, it is imperative that a good understanding of the EBL is included. In this work, an investigation into the imprint of the EBL on the observed spectra of high-redshift Fermi-LAT active galactic nuclei is presented. By fitting the spectrum below ˜10 GeV, an estimation of the unabsorbed intrinsic source spectrum is obtained; by applying this spectrum to data up to 300 GeV, it is then possible to derive a scaling factor for different EBL models. A second approach uses five sources (PKS 0426-380, 4C +55.17, Ton 116, PG 1246+586 and RBS 1432) that were found to exhibit very high energy (VHE) emission (Eγ > 100 GeV). Through Monte Carlo simulations, it is shown that the observation of VHE photons, despite the large distances of these objects, is consistent with current EBL models. Many of these sources would be observable with the upcoming ground-based observatory, the Cherenkov Telescope Array, leading to a better understanding of the EBL.
Are there good probes for the di-neutron correlation in light neutron-rich nuclei?
Hagino, K
2015-01-01
The di-neutron correlation is a spatial correlation with which two valence neutrons are located at a similar position inside a nucleus. We discuss possible experimental probes for the di-neutron correlation. This includes the Coulomb breakup and the pair transfer reactions of neutron-rich nuclei, and the direct two-neutron decays of nuclei beyond the neutron drip-line.
Sugiyama, Yuka; Kadota, Akeo
2011-03-01
Chloroplasts change their positions in the cell depending on the light conditions. In the dark, chloroplasts in fern prothallia locate along the anticlinal wall (dark position). However, chloroplasts become relocated to the periclinal wall (light position) when the light shines perpendicularly to the prothallia. Red light is effective in inducing this relocation in Adiantum capillus-veneris, and neochrome1 (neo1) has been identified as the red light receptor regulating this movement. Nevertheless, we found here that chloroplasts in neo1 mutants still become relocated from the dark position to the light position under red light. We tested four neo1 mutant alleles (neo1-1, neo1-2, neo1-3, and neo1-4), and all of them showed the red-light-induced chloroplast relocation. Furthermore, chloroplast light positioning under red light occurred also in Pteris vittata, another fern species naturally lacking the neo1-dependent phenomenon. The light positioning of chloroplasts occurred independently of the direction of red light, a response different to that of the neo1-dependent movement. Photosynthesis inhibitors 3-(3,4 dichlorophenyl)-1,1-dimethylurea or 2,5-dibromo-3-isopropyl-6-methyl-p-benzoquinone blocked this movement. Addition of sucrose (Suc) or glucose to the culture medium induced migration of the chloroplasts to the periclinal wall in darkness. Furthermore, Suc could override the effects of 3-(3,4 dichlorophenyl)-1,1-dimethylurea. Interestingly, the same light positioning was evident for nuclei under red light in the neo1 mutant. The nuclear light positioning was also induced in darkness with the addition of Suc or glucose. These results indicate that photosynthesis-dependent nondirectional movement contributes to the light positioning of these organelles in addition to the neo1-dependent directional movement toward light.
Directory of Open Access Journals (Sweden)
F. L. T. Gonçalves
2012-07-01
Full Text Available Many studies from the last decades have shown that airborne microorganisms can be intrinsically linked to atmospheric processes. Certain bacteria may constitute the most active ice nuclei found in the atmosphere and might have some influence on the formation of ice crystals in clouds. This study deals with the ice nucleation activity of Pseudomonas syringae inside of thunderstorms through numerical simulations using BRAMS (Brazilian Regional Atmospheric Model System. The numerical simulations were developed in order to investigate the effect on the total amount of rainwater as a function of ice nuclei (IN P. syringae concentrations with different scenarios (classified as S2 to S4 scenarios corresponding to a maximum of 10^{2} to 10^{4} IN bacteria per liter of cloud water plus the BRAMS default (classified as S5 scenario. Additionally, two other scenarios were included without any IN (S1 and the sum of RAMS default and S4 scenario (classified as S6. The chosen radiosonde data is for 3 March 2003, typical summertime in São Paulo City which presents a strong convective cell. The objective of the simulations was to analyze the effect of the IN concentrations on the BRAMS modeled cloud properties and precipitation. The simulated electrification of the cloud permitted analysis of the total flashes estimated from precipitable and non-precipitable ice mass fluxes in two different lightning frequencies. Among all scenarios, only S4 and S6 presented a tendency to decrease the total cloud water, and all bacteria scenarios presented a tendency to decrease the total amount of rain (−8%, corroborating other reports in the literature. All bacteria scenarios also present higher precipitable ice concentrations compared to S5 scenario, the RAMS default. The main results present the total flash number per simulation as well. From the results, the total flash numbers, from both lightning frequencies, in S4 and S6 scenarios
Directory of Open Access Journals (Sweden)
F. L. T. Gonçalves
2011-09-01
Full Text Available Many studies from the last decades have shown that airborne microorganisms can be intrinsically related with atmospheric processes. Certain bacteria may constitute the most active ice nuclei found in the atmosphere and might have some influence on the formation of ice crystals in clouds. This study deals with the ice nucleation activity of Pseudomonas syringae inside of thunderstorms through numerical simulations using BRAMS (Brazilian Regional Atmospheric Model System. The numerical simulations were developed in order to investigate the effect on the total amount of rainwater as a function of ice nuclei (IN P. syringae concentrations with different scenarios (classified as S2 to S4 scenarios corresponding to maximum 10^{2} to 10^{3} IN bacteria per liter of cloud water plus the RAMS default (classified as S5 scenario. Additionally, two other scenarios were included without any IN (S1 and the sum of RAMS default and S4 scenario (classified as S6. The chosen radiosonde data is for 3 March 2003, typical summertime in São Paulo City which presents a strong convective cell. The objective of the simulations was to analyze the effect of the IN concentrations on the BRAMS modeled cloud properties and precipitation. The simulated electrification of the cloud permitted analysis of the total flashes estimated from precipitable and non-precipitable ice mass fluxes. Among all scenarios, only S4 and S6 presented a tendency to decrease the total cloud water, and all bacteria scenarios presented a tendency to decrease the total amount of rain at the ground (−8%, agreeing with literature. All bacteria scenarios also present higher precipitable ice concentrations compared to S5 scenario, the RAMS default. The main results present the total flash number per simulation as well. From the results, the total flash number, in the simulation S4 and S6, is twice higher than the RAMS default. Even the smaller bacteria
-decay measurements for N > 40 Mn nuclei and inference of collectivity for neutron-rich Fe isotopes
Energy Technology Data Exchange (ETDEWEB)
Daugas, J [CEA, DAM, DIF, Arpajon cedex, France; Delaroche, J. P. [CEA, DAM, DIF, Arpajon cedex, France; Pfutzner, M. [University of Warsaw; Sawicka, M. [University of Warsaw; Becker, F. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Belier, G. [CEA, DAM, DIF, Arpajon cedex, France; Bingham, C. R. [University of Tennessee, Knoxville (UTK); Borcea, C. [IFIN, Bucharest-Magurele, Romania; Bouchez, E. [CEA, Cetre de Sacaly, Gif-sur-Yvette, France; Buta, A. [IFIN, Bucharest-Magurele, Romania; Dragulescu, E. [IFIN, Bucharest-Magurele, Romania; Georgiev, G. [Grand Accelerateur National d' Ions Lourds (GANIL); Giovinazzo, J. [CEN Bordeaux-Gradignan/CNRS, France; Girod, M. [CEA, DAM, DIF, Arpajon cedex, France; Grawe, H. [GSI-Hemholtzzentrum fur Schwerionenforschung, Darmstadt, Germany; Grzywacz, R. [University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL); Hammache, F. [CNRS/IN2P3, Orsay, France; Ibrahim, F. [CNRS/IN2P3, Orsay, France; Lewitowicz, M. [Grand Accelerateur National d' Ions Lourds (GANIL); Libert, J. [CNRS/IN2P3, Orsay, France; Mayet, P. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Meot, V. [CEA, DAM, DIF, Arpajon cedex, France; Negoita, F. [IFIN, Bucharest-Magurele, Romania; de Oliveira Santos, F. [Grand Accelerateur National d' Ions Lourds (GANIL); Perru, O. [CEA, DAM, DIF, Arpajon cedex, France; Roig, O. [CEA, DAM, DIF, Arpajon cedex, France; Rykaczewski, Krzysztof Piotr [ORNL; Saint-Laurent, M. G. [Grand Accelerateur National d' Ions Lourds (GANIL); Sauvestre, J. E. [CEA, France; Sorlin, O. [Grand Accelerateur National d' Ions Lourds (GANIL); Stanoiu, M. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Stefan, I. [CNRS/IN2P3, Orsay, France; Stodel, Ch. [Grand Accelerateur National d' Ions Lourds (GANIL); Theisen, Ch. [LSCE/CEA, Gif-sur-Yvette, France; Verney, D. [CNRS/IN2P3, Orsay, France; Zylicz, J. [University of Warsaw
2011-01-01
A decay spectroscopic study of the neutron-rich isotopes has been performed using fragmentation of a 86Kr primary beam. Fragments from this reaction have been selected by the LISE2000 spectrometer at the Grand Acc el erateur National d Ions Lourds (GANIL). Half-lives of 29 isotopes, including the first ones identified for 61Ti (15 4 ms), 64V (19 8 ms), and 71Fe (28 5 ms), have been determined and compared with model predictions. 67,68Mn -delayed rays were observed for the first time. The branching for the -delayed neutron emission was measured to be greater than 10(5)% in the 67Mn decay. The 67Fe isomeric level is firmly determined at higher energy than assigned in previous works. The excitation energies of the first (2+) and (4+) states of 68Fe are suggested to lie at 522(1) and 1389(1) keV, respectively, thus bringing confirmation of assignments based on in-beam -ray spectroscopy. Beyond-mean-field calculations with the Gogny D1S force have been performed for even-mass nuclei through the Fe isotopic chain. Not only 68Fe but most of the neutron-rich Fe isotopes with neutron numbers below N = 50 are interpreted as soft rotors. The calculated mean occupancy of the neutron g9/2 and d5/2 orbitals in correlated ground states is steadily growing with increasing neutron number throughout the isotopic chain. Interpretation of 67Fe data is based upon the present calculations for the 66Fe and 68Fe even cores.
Production of light (anti-)nuclei and (anti-)hypernuclei with ALICE at the LHC
CERN. Geneva
2017-01-01
The measurements in smaller collision systems may also provide an input to cosmological searches for segregated primordial anti-matter and dark matter, since anti-nuclei produced in pp and p--A collisions in interstellar space represent a background source in these measurements. Thanks to its excellent particle identification and tracking capabilities, the ALICE detector allows for the measurement of deuterons, tritons, 3He, 4He and their corresponding anti-nuclei. Moreover, the secondary vertices from the mesonic decays of (anti-)hypernuclei can ...
One- and two neutron decay of light neutron-rich nuclei
Thoennessen, Michael
2014-09-01
Direct reactions with radioactive beams have been used very successfully to populate and measure nuclei beyond the neutron dripline and neutron unbound excited states of nuclei close to the neutron dripline. The use of different reactions (for example neutron removal and proton removal) to populate the same final nucleus can be used to selectively populate different states. Recent results from the MoNA-LISA setup at the NSCL, including 10He, 10,11Li, and 12,13Be will be presented. Direct reactions with radioactive beams have been used very successfully to populate and measure nuclei beyond the neutron dripline and neutron unbound excited states of nuclei close to the neutron dripline. The use of different reactions (for example neutron removal and proton removal) to populate the same final nucleus can be used to selectively populate different states. Recent results from the MoNA-LISA setup at the NSCL, including 10He, 10,11Li, and 12,13Be will be presented. This work was supported in part by the NSF, Grant PHY-11-02511.
Losa, C; Dossing, T; Vigezzi, E; Broglia, R A
2010-01-01
We present a calculation of the properties of vibrational states in deformed, axially--symmetric even--even nuclei, within the framework of a fully self--consistent Quasparticle Random Phase Approximation (QRPA). The same Skyrme energy density and density-dependent pairing functionals are used to calculate the mean field and the residual interaction in the particle-hole and particle-particle channels. We have tested our software in the case of spherical nuclei against fully self consistent calculations published in the literature, finding excellent agreement. We investigate the consequences of neglecting the spin-orbit and Coulomb residual interactions in QRPA. Furthermore we discuss the improvement obtained in the QRPA result associated with the removal of spurious modes. Isoscalar and isovector responses in the deformed ${}^{24}{}^{-}{}^{26}$Mg, ${}^{34}$Mg isotopes are presented and compared to experimental findings.
Stark, Julian; Rothe, Thomas; Kieß, Steffen; Simon, Sven; Kienle, Alwin
2016-04-01
Single cell nuclei were investigated using two-dimensional angularly and spectrally resolved scattering microscopy. We show that even for a qualitative comparison of experimental and theoretical data, the standard Mie model of a homogeneous sphere proves to be insufficient. Hence, an accelerated finite-difference time-domain method using a graphics processor unit and domain decomposition was implemented to analyze the experimental scattering patterns. The measured cell nuclei were modeled as single spheres with randomly distributed spherical inclusions of different size and refractive index representing the nucleoli and clumps of chromatin. Taking into account the nuclear heterogeneity of a large number of inclusions yields a qualitative agreement between experimental and theoretical spectra and illustrates the impact of the nuclear micro- and nanostructure on the scattering patterns.
Neutron-pair emission following pi /sup -/ absorption on some light nuclei
Furic, M; Engelhardt, H D; Klotz, W D; Takeutchi, F; Ullrich, H
1977-01-01
Large-area position-sensitive neutron counters with subnanosecond time resolution have been used to study the ( pi /sup -/,2n) reaction with a resolution comparable to or better than the existing ( pi /sup + /,2p) data. The measurement of the momenta of both neutrons enabled a determination of the excitation energy spectra of the residual nuclei to be made. The momentum distributions for the absorbing nucleon pair were also extracted assuming the quasifree mechanism for the ( pi /sup -/,2n) process. The pi /sup -/ beam obtained from the CERN SC II was brought to rest in the targets of /sup 9/Be, /sup 10/B, /sup 12/C and /sup 14/N. The excitation spectra of the residual nuclei were compared with the predictions based on the coefficients of fractional parentage for the removal of the two nucleons. The data and the predictions are in good agreement within the experimental resolution. (4 refs).
Energy Technology Data Exchange (ETDEWEB)
Lister, C.J. [Department of Physics, University of Massachusetts, Lowell, Lowell MA 01854 (United States); McCutchan, E.A. [National Nuclear Data Center, Brookhaven National Laboratory, Upton, NY 11973-5000 (United States)
2014-06-15
A new generation of ab-initio calculations, based on realistic two- and three-body forces, is having a profound impact on our view of how nuclei work. To improve the numerical methods, and the parameterization of 3-body forces, new precise data are needed. Electromagnetic transitions are very sensitive to the dynamics which drive mixing between configurations. We have made a series of precise (< 3%) measurements of electromagnetic transitions in the A=10 nuclei {sup 10}C and {sup 10}Be by using the Doppler Shift Attenuation method carefully. Many interesting features can be reproduced including the strong α clustering. New measurements on {sup 8}Be and {sup 12}Be highlight the interplay between the alpha clusters and their valence neutrons.
Geometrical symmetries of nuclear systems: D(3h) and T(d) symmetries in light nuclei
Bijker, Roelof
2016-01-01
The role of discrete (or point-group) symmetries in alpha-cluster nuclei is discussed in the framework of the algebraic cluster model which describes the relative motion of the alpha-particles. Particular attention is paid to the discrete symmetry of the geometric arrangement of the alpha-particles, and the consequences for the structure of the corresponding rotational bands. The method is applied to study cluster states in the nuclei 12C and 16O. The observed level sequences can be understood in a simple way as a consequence of the underlying discrete symmetry that characterizes the geometrical configuration of the alpha-particles, i.e. an equilateral triangle with D(3h) symmetry for 12C, and a tetrahedron with T(d) symmetry for 16O. The structure of rotational bands provides a fingerprint of the underlying geometrical configuration of alpha-particles.
Bulk properties of light deformed nuclei derived from a medium-modified meson-exchange interaction
Grümmer, F; Ma, Z Y; Krewald, S
1996-01-01
Deformed Hartree-Fock-Bogoliubov calculations for finite nuclei are carried out. As residual interaction, a Brueckner G-matrix derived from a meson-exchange potential is taken. Phenomenological medium modifications of the meson masses are introduced. The binding energies, radii, and deformation parameters of the Carbon, Oxygen, Neon, and Magnesium isotope chains are found to be in good agreement with the experimental data.
Study of quark mass dependence of binding energy for light nuclei in 2+1 flavor lattice QCD
Yamazaki, Takeshi; Kuramashi, Yoshinobu; Ukawa, Akira
2015-01-01
We investigate the formation of light nuclei with the nuclear mass number less than or equal to four in 2+1 flavor QCD using a non-perturbative improved Wilson quark and Iwasaki gauge actions. The quark mass is decreased from our previous work to the one corresponding to the pion mass of 0.30 GeV. In each multi-nucleon channel, the energy shift of the ground state relative to the assembly of free nucleons is calculated on two volumes, whose spatial extents are 4.3 fm and 5.8 fm. From the volume dependence of the energy shift, we distinguish a bound state of multi nucleons from an attractive scattering state. We find that all the ground states measured in this calculation are bound states. As in the previous studies at larger $m_\\pi$, our result indicates that at $m_\\pi = 0.30$ GeV the effective interaction between nucleons in the light nuclei is relatively stronger than the one in nature, since the results for the binding energies are larger than the experimental values and a bound state appears in the dineut...
Corrections for nuclear interaction in the case of light nuclei detection in NaI(Tl) crystal
Energy Technology Data Exchange (ETDEWEB)
Avdejchikov, V.V.; Bogdanov, A.I.; Zlomanchuk, Yu.; Majsyukov, V.D.; Abashidze, L.I.; Budilov, V. A.; Zhidkov, N.K.; Nikitin, V.A.; Nomokonov, P.V.; Povtorejko, A.A.
1985-01-01
Losses for nuclear interaction in a NaI(Tl) monocrystal forming together with a silicon semiconductor detector a ..delta..E-E telescope used for the light nucleus identification were measured experimentally. The measurements were performed with 3He nucleus beam extracted from the JINR synchrophasotron at five energy values: 428; 387; 295; 172 and 70 MeV. Nuclear losses for hydrogen and helium isotopes in NaI(Tl) crystals were calculated theoretically using the Glauber model. Comparing the estimated and experimental data obtained the conclusion is drawn on the serviceability of the model considered for determining corrections for the nuclear interaction during light nuclei recording by scintillation NaI(Tl) crystal detectors.
Method for precise charge measurements of relativistic light nuclei, Z<=3, in nuclear track emulsion
Energy Technology Data Exchange (ETDEWEB)
Bloomer, M.A.; Heckman, H.H.; Karant, Y.J. (California Univ., Berkeley (USA). Div. of Nuclear Science)
1983-09-15
A technique for precise charge measurement of particle tracks in nuclear emulsion is described. The method is based on measurements of the lacunarity, i.e., fractional transparency, and/or the fractional opacity in the linear track structure of ionization tracks observed in the developed emulsion. The method yields estimates of charge for relativistic Z=1 and 2 nuclei to a precision of proportional +- 0.05 charge units, in agreement with Barkas' theoretical model of track structure. The technique is applicable up to Zapprox.=6, but with diminished charge resolution with increasing charge above Z=3. Systematics that affect the accuracy of the method are noted and discussed.
Monte-Carlo calculations of light nuclei with the Reid potential
Energy Technology Data Exchange (ETDEWEB)
Lomnitz-Adler, J. (Universidad Nacional Autonoma de Mexico, Mexico City. Inst. de Fisica)
1981-01-01
A Monte-Carlo method is developed to calculate the binding energy and density distribution of the /sup 3/H and /sup 4/He nuclei for a variational wave function written as a symmetrized product of correlation operators. The upper bounds obtained with the Reid potential are -6.86 +- .08 and -22.9 +- .5 MeV respectively. The Coulomb interaction in /sup 4/He is ignored. The calculated density distributions have reasonable radii, but they do not show any dip at the center.
Three-Body Potentials in {\\varvec{α }}-Particle Model of Light Nuclei
Ishikawa, Souichi
2017-03-01
In three-body model calculations of atomic nuclei, e.g., the {}^{12}C nucleus as α -α -α system and the {}9Be nucleus as α -α - n system, the Hamiltonians of the systems consisting of two- and three-body potentials are important inputs. However, our knowledge of three-body potentials is quite restricted. In this paper, I will examine a relation between α -α -α and α -α - n three-body potentials that is obtained in a simple cluster model picture, which gives a phenomenological constraint condition on the three-body potential models to be used.
No-Core Shell Model Calculations in Light Nuclei with Three-Nucleon Forces
Energy Technology Data Exchange (ETDEWEB)
Barrett, B R; Vary, J P; Nogga, A; Navratil, P; Ormand, W E
2004-01-08
The ab initio No-Core Shell Model (NCSM) has recently been expanded to include nucleon-nucleon (NN) and three-nucleon (3N) interactions at the three-body cluster level. Here it is used to predict binding energies and spectra of p-shell nuclei based on realistic NN and 3N interactions. It is shown that 3N force (3NF) properties can be studied in these nuclear systems. First results show that interactions based on chiral perturbation theory lead to a realistic description of {sup 6}Li.
Study of light nuclei (antinuclei) production and Photon Multiplicity Detector in ALICE at the LHC
Sharma, Natasha
The primary goal of the heavy-ion program at the Large Hadron Collider (LHC) at CERN, Geneva, Switzerland is to search for the possible formation of Quark-Gluon Plasma. It also aims to understand the production mechanism of matter and antimatter in a collision. The details of the ALICE detector and its subsystems are presented in this thesis. The details of the fabrication, electronics, readout and installation of the PMD (Photon Multiplicity Detector) in the ALICE experiment are also presented. The PMD detector measures the photons in the 2.3 $<$ $\\eta$ $<$ 3.7 region. The software details including the reconstruction chain are also discussed. The detailed study of efficiency and purity calculation for the PMD detector using the embedding technique are also presented for pp and Pb-Pb collisions. The detailed study of nuclei and anti-nuclei production using the statistical-thermal model (THERMUS) is discussed. Their ratios are compared with the existing experimental data and predictions are made for pp ...
Evidence for Symplectic Symmetry in Ab Initio No-Core Shell Model Results for Light Nuclei
Energy Technology Data Exchange (ETDEWEB)
Dytrych, Tomas; Sviratcheva, Kristina D.; Bahri, Chairul; Draayer, Jerry P.; /Louisiana State U.; Vary, James P.; /Iowa State U. /LLNL, Livermore /SLAC
2007-04-24
Clear evidence for symplectic symmetry in low-lying states of {sup 12}C and {sup 16}O is reported. Eigenstates of {sup 12}C and {sup 16}O, determined within the framework of the no-core shell model using the JISP16 NN realistic interaction, typically project at the 85-90% level onto a few of the most deformed symplectic basis states that span only a small fraction of the full model space. The results are nearly independent of whether the bare or renormalized effective interactions are used in the analysis. The outcome confirms Elliott's SU(3) model which underpins the symplectic scheme, and above all, points to the relevance of a symplectic no-core shell model that can reproduce experimental B(E2) values without effective charges as well as deformed spatial modes associated with clustering phenomena in nuclei.
Secondary cosmic ray nuclei in the light of the Single Source Model
Erlykin, Anatoly
2016-01-01
Evidence for a local 'Single Source' of cosmic rays is amassing by way of the recent precise measurements of various cosmic ray energy spectra from the AMS-02 instrument. To observations of individual cosmic ray nuclei, electrons, positrons and antiprotons must now be added the determination of the boron-to-carbon ratio and the energy spectrum of lithium to 2000 GV with high precision. Our analysis leads us to claim that, with certain assumptions about the propagation in the Galaxy, the results confirm our arguments regarding the presence of a local single source, perhaps, a supernova remnant (SNR). An attempt is made to determine some of the properties of this SNR and its progenitor star.
A statistical model for simulating the emission of light particles from excited nuclei
Sannikov, A. V.; Savitskaya, E. N.
2016-05-01
The algorithms and basic equations of a novel evaporation model that have been implemented in the program package EVAP15 are detailed. The level density of an excited nucleus is described by the composite Gilbert-Cameron formula with parameter values as suggested by the IAEA working group RIPL-3. Special attention is paid to the cross sections of inverse reactions and, in particular, to those for the interactions of low-energy neutrons with nuclei and for crossing of the Coulomb barrier by low-energy charged particles. The model predictions are compared with a large volume of experimental data on the spectra of particles emitted in the reactions ( n, xn), ( n, xp), and ( n, xα) induced by neutrons with energy near 14 MeV and on the four spectra for the reaction ( p, xp) induced by 62-MeV protons.
Secondary Cosmic Ray Nuclei in the Light of the Single Source Model
Erlykin, Anatoly
2016-01-01
Evidence for a local 'Single Source' of cosmic rays is amassing by way of the recent precise measurements of various cosmic ray energy spectra from the AMS-02 instrument. To observations of individual cosmic ray nuclei, electrons, positrons and antiprotons must now be added the determination of the boron-to-carbon ratio and the energy spectrum of lithium to 2000 GV with high precision. Our analysis leads us to claim that, with certain assumptions about propagation in the Galaxy, the results confirm our arguments regarding the presence of a local single source, perhaps, a supernova remnant (SNR). An attempt is made to determine some of the properties of this SNR and its progenitor star.
Lensky, Vadim; Birse, Michael C.; Walet, Niels R.
2016-09-01
We construct a coordinate-space potential based on pionless effective field theory (EFT) with a Gaussian regulator. Charge-symmetry breaking is included through the Coulomb potential and through two- and three-body contact interactions. Starting with the effective field theory potential, we apply the stochastic variational method to determine the ground states of nuclei with mass number A ≤4 . At next-to-next-to-leading order, two out of three independent three-body parameters can be fitted to the three-body binding energies. To fix the remaining one, we look for a simultaneous description of the binding energy of 4He and the charge radii of 3He and 4He. We show that at the order considered we can find an acceptable solution, within the uncertainty of the expansion. We find that the EFT expansion shows good agreement with empirical data within the estimated uncertainty, even for a system as dense as 4He.
Lensky, Vadim; Walet, Niels R
2016-01-01
We construct a coordinate-space potential based on pionless effective field theory with a Gaussian regulator. Charge-symmetry breaking is included through the Coulomb potential and through two- and three-body contact interactions. Starting with the effective field theory potential, we apply the stochastic variational method to determine the ground states of nuclei with mass number $A\\leq 4$. At next-to-next-to-leading order, two out of three independent three-body parameters can be fitted to the three-body binding energies. To fix the remaining one, we look for a simultaneous description of the binding energy of $^4$He and the charge radii of $^3$He and $^4$He. We show that at the order considered we can find an acceptable solution, within the uncertainty of the expansion. We find that the EFT expansion shows good convergence, even for a system as dense as $^4$He.
Proton Halo or Skin in the Excited States of Light Nuclei
Institute of Scientific and Technical Information of China (English)
陈金根; 蔡翔舟; 张虎勇; 沈文庆; 任中洲; 蒋维洲; 马余刚; 钟晨; 魏义彬; 郭威; 周星飞; 马国亮; 王鲲
2003-01-01
Properties of nuclei 13,15N and 9B are investigated in the relativistic mean-field theory with NLZ and NL3 force parameters. The calculated binding energies are very close to the experimental ones. The calculations show that the first excited state (1p1/2) in 9B, the first excited state (2s1/2) in 13N and the second excited state (2s1/2) in 15N are weakly bound. In particular, for 13N and 15N, the proton density distributions in the two above excited states have a long tail and the rms radii of the last proton are greatly larger compared with their respective matter radii. It is predicted that a proton halo exists in the first excited state of 13N and in the second excited state of 15N, respectively. It also indicates that the first excited state in 9B is a proton skin state.
Structure of light neutron-rich nuclei and mechanism of elastic proton scattering
Energy Technology Data Exchange (ETDEWEB)
Ibraeva, E. T., E-mail: ibr@inp.kz [National Nuclear Center of the Republic of Kazakhstan, Institute of Nuclear Physics (Kazakhstan); Zhusupov, M. A. [Al-Farabi Kazakh National University (Kazakhstan); Imambekov, O. [National Nuclear Center of the Republic of Kazakhstan, Institute of Nuclear Physics (Kazakhstan)
2011-11-15
Differential cross sections for elastic p{sup 6}He, p{sup 8}Li, and p{sup 9}Li scattering at two energies of 70 and 700 MeV per nucleon were calculated within the Glauber theory of multiple diffractive scattering. Threeparticle wave functions ({alpha}-n-n for {sup 6}He, {alpha}-t-n for {sup 8}Li, and {sup 7}Li-n-n for {sup 9}Li) were used for realistic potentials of intercluster interactions. The sensitivity of elastic scattering to proton-nucleus interaction and to the structure of nuclei was explored. In particular, the dependence of the differential cross section on the contribution of higher order collisions, on scattering on the core and peripheral nucleons, and on the contribution of small wave-function components and their asymptotic behavior was determined. A comparison with available experimental data and with the results of calculations within different formalisms was performed.
Energy Technology Data Exchange (ETDEWEB)
Kabir, Al Amin [Kent State Univ., Kent, OH (United States)
2015-12-01
Analysis of high-energy electron scattering has been used to determine the charge radii of nuclei for several decades. Recent analysis of the Lamb shift in muonic hydrogen found an r.m.s. radius significantly different than the electron scattering result. To understand this puzzle we have analyzed the "LEDEX" data for the (e, e'p) reaction. This experiment includes measurements on several light nuclei, hydrogen, deuterium, lithium, boron, and carbon. To test our ability to measure absolute cross sections, as well as our ability to extract the charge radius, we tested our technique against the extremely well-measured carbon case and found excellent agreement using the Fourier-Bessel parametrization. We then extended the procedure to boron and lithium, which show nice agreement with the latest theoretical calculations. For hydrogen, we see clearly the limits of this technique and therefore, the charge radius is determined from the traditional extrapolation to q^{2} = 0. We will show that there is a model dependence in extracting the charge radius of hydrogen and its unambiguous determination is very difficult with available electron-scattering measurements.
Energy Technology Data Exchange (ETDEWEB)
Sawahata, K. [Institute of Physics, University of Tsukuba, Ibaraki 305-8571 (Japan); Ozawa, A., E-mail: ozawa@tac.tsukuba.ac.jp [Institute of Physics, University of Tsukuba, Ibaraki 305-8571 (Japan); Saito, Y.; Abe, Y.; Ichikawa, Y.; Inaba, N.; Ishibashi, Y. [Institute of Physics, University of Tsukuba, Ibaraki 305-8571 (Japan); Kitagawa, A. [National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Matsunaga, S. [Department of Physics, Saitama University, Saitama 338-8570 (Japan); Moriguchi, T.; Nagae, D.; Okada, S. [Institute of Physics, University of Tsukuba, Ibaraki 305-8571 (Japan); Sato, S. [National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Suzuki, S. [Institute of Physics, University of Tsukuba, Ibaraki 305-8571 (Japan); Suzuki, T.; Takeuchi, Y.; Yamaguchi, T. [Department of Physics, Saitama University, Saitama 338-8570 (Japan); Zenihiro, J. [RIKEN Nishina Center, Wako, Saitama 351-0198 (Japan)
2017-05-15
We investigated charge-changing processes (total charge-changing cross sections and partial charge-changing cross sections) for light proton-rich nuclei ({sup 34–36}Ar, {sup 33}Cl, {sup 25–28}Si) at around 300A MeV on carbon and solid-hydrogen targets. We estimated the nuclear proton point radii of {sup 33}Cl and {sup 25,26,27}Si from the observed total charge-changing cross sections by using Glauber-model calculations with a phenomenological correction factor. Furthermore, we estimated the proton skin thickness for {sup 33}Cl coupled with its previously observed matter radius. From investigations of the partial charge-changing cross sections, clear zigzag pattern was observed for all isotopes. The present studies suggest that the pattern may be common in the proton-rich side, and depends on the odd–even nature of the fragment charge.
Local chiral potentials with Δ-intermediate states and the structure of light nuclei
Piarulli, Maria
2017-01-01
We present a fully local nucleon-nucleon potential in chiral effective field theory (χEFT) retaining pions, nucleons and Δ-isobars as explicit degrees of freedom, and use it in hypersperical-harmonics and quantum Monte Carlo calculations of ground and excited states of 3H, 3He, 4He, 6He, and 6Li nuclei. The calculation of the potential is carried out by including one- and two-pion-exchange contributions up to next-to-next-to-leading order (N2LO) and contact interactions up to next-to-next-to-next-to-leading order (N3LO). The low-energy constants multiplying these contact interactions are fitted to the 2013 Granada database in two different ranges of laboratory energies, either 0-125 MeV or 0-200 MeV, and to the deuteron binding energy and nn singlet scattering length. Fits to these data are performed for three models characterized by long- and short-range cutoffs, RL and RS respectively, ranging from (RL ,RS) =(1 . 2 , 0 . 8) fm down to (0 . 8 , 0 . 6) fm. The long-range (short-range) cutoff regularizes the one- and two-pion exchange (contact) part of the potential.
Adam, J.; Adamová, D.; Aggarwal, M. M.; Aglieri Rinella, G.; Agnello, M.; Agrawal, N.; Ahammed, Z.; Ahmed, I.; Ahn, S. U.; Aimo, I.; Aiola, S.; Ajaz, M.; Akindinov, A.; Alam, S. N.; Aleksandrov, D.; Alessandro, B.; Alexandre, D.; Alfaro Molina, R.; Alici, A.; Alkin, A.; Alme, J.; Alt, T.; Altinpinar, S.; Altsybeev, I.; Alves Garcia Prado, C.; Andrei, C.; Andronic, A.; Anguelov, V.; Anielski, J.; Antičić, T.; Antinori, F.; Antonioli, P.; Aphecetche, L.; Appelshäuser, H.; Arcelli, S.; Armesto, N.; Arnaldi, R.; Aronsson, T.; Arsene, I. C.; Arslandok, M.; Augustinus, A.; Averbeck, R.; Azmi, M. D.; Bach, M.; Badalà, A.; Baek, Y. W.; Bagnasco, S.; Bailhache, R.; Bala, R.; Baldisseri, A.; Ball, M.; Baltasar Dos Santos Pedrosa, F.; Baral, R. C.; Barbano, A. M.; Barbera, R.; Barile, F.; Barnaföldi, G. G.; Barnby, L. S.; Barret, V.; Bartalini, P.; Bartke, J.; Bartsch, E.; Basile, M.; Bastid, N.; Basu, S.; Bathen, B.; Batigne, G.; Batista Camejo, A.; Batyunya, B.; Batzing, P. C.; Bearden, I. G.; Beck, H.; Bedda, C.; Behera, N. K.; Belikov, I.; Bellini, F.; Bello Martinez, H.; Bellwied, R.; Belmont, R.; Belmont-moreno, E.; Belyaev, V.; Bencedi, G.; Beole, S.; Berceanu, I.; Bercuci, A.; Berdnikov, Y.; Berenyi, D.; Bertens, R. A.; Berzano, D.; Betev, L.; Bhasin, A.; Bhat, I. R.; Bhati, A. K.; Bhattacharjee, B.; Bhom, J.; Bianchi, L.; Bianchi, N.; Bianchin, C.; Bielčík, J.; Bielčíková, J.; Bilandzic, A.; Biswas, S.; Bjelogrlic, S.; Blanco, F.; Blau, D.; Blume, C.; Bock, F.; Bogdanov, A.; Bøggild, H.; Boldizsár, L.; Bombara, M.; Book, J.; Borel, H.; Borissov, A.; Borri, M.; Bossú, F.; Botje, M.; Botta, E.; Böttger, S.; Braun-munzinger, P.; Bregant, M.; Breitner, T.; Broker, T. A.; Browning, T. A.; Broz, M.; Brucken, E. J.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Bufalino, S.; Buncic, P.; Busch, O.; Buthelezi, Z.; Buxton, J. T.; Caffarri, D.; Cai, X.; Caines, H.; Calero Diaz, L.; Caliva, A.; Calvo Villar, E.; Camerini, P.; Carena, F.; Carena, W.; Castillo Castellanos, J.; Castro, A. J.; Casula, E. A. R.; Cavicchioli, C.; Ceballos Sanchez, C.; Cepila, J.; Cerello, P.; Chang, B.; Chapeland, S.; Chartier, M.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Chelnokov, V.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chibante Barroso, V.; Chinellato, D. D.; Chochula, P.; Choi, K.; Chojnacki, M.; Choudhury, S.; Christakoglou, P.; Christensen, C. H.; Christiansen, P.; Chujo, T.; Chung, S. U.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Colamaria, F.; Colella, D.; Collu, A.; Colocci, M.; Conesa Balbastre, G.; Conesa Del Valle, Z.; Connors, M. E.; Contreras, J. G.; Cormier, T. M.; Corrales Morales, Y.; Cortés Maldonado, I.; Cortese, P.; Cosentino, M. R.; Costa, F.; Crochet, P.; Cruz Albino, R.; Cuautle, E.; Cunqueiro, L.; Dahms, T.; Dainese, A.; Danu, A.; Das, D.; Das, I.; Das, S.; Dash, A.; Dash, S.; De, S.; De Caro, A.; De Cataldo, G.; De Cuveland, J.; De Falco, A.; De Gruttola, D.; De Marco, N.; De Pasquale, S.; Deisting, A.; Deloff, A.; Dénes, E.; D'erasmo, G.; Di Bari, D.; Di Mauro, A.; Di Nezza, P.; Diaz Corchero, M. A.; Dietel, T.; Dillenseger, P.; Divià, R.; Djuvsland, Ø.; Dobrin, A.; Dobrowolski, T.; Domenicis Gimenez, D.; Dönigus, B.; Dordic, O.; Dubey, A. K.; Dubla, A.; Ducroux, L.; Dupieux, P.; Ehlers, R. J.; Elia, D.; Engel, H.; Erazmus, B.; Erhardt, F.; Eschweiler, D.; Espagnon, B.; Estienne, M.; Esumi, S.; Eum, J.; Evans, D.; Evdokimov, S.; Eyyubova, G.; Fabbietti, L.; Fabris, D.; Faivre, J.; Fantoni, A.; Fasel, M.; Feldkamp, L.; Felea, D.; Feliciello, A.; Feofilov, G.; Ferencei, J.; Fernández Téllez, A.; Ferreiro, E. G.; Ferretti, A.; Festanti, A.; Figiel, J.; Figueredo, M. A. S.; Filchagin, S.; Finogeev, D.; Fionda, F. M.; Fiore, E. M.; Fleck, M. G.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Francescon, A.; Frankenfeld, U.; Fuchs, U.; Furget, C.; Furs, A.; Fusco Girard, M.; Gaardhøje, J. J.; Gagliardi, M.; Gago, A. M.; Gallio, M.; Gangadharan, D. R.; Ganoti, P.; Gao, C.; Garabatos, C.; Garcia-solis, E.; Gargiulo, C.; Gasik, P.; Germain, M.; Gheata, A.; Gheata, M.; Ghosh, P.; Ghosh, S. K.; Gianotti, P.; Giubellino, P.; Giubilato, P.; Gladysz-dziadus, E.; Glässel, P.; Goméz Coral, D. M.; Gomez Ramirez, A.; González-zamora, P.; Gorbunov, S.; Görlich, L.; Gotovac, S.; Grabski, V.; Graczykowski, L. K.; Grelli, A.; Grigoras, A.; Grigoras, C.; Grigoriev, V.; Grigoryan, A.; Grigoryan, S.; Grinyov, B.; Grion, N.; Grosse-oetringhaus, J. F.; Grossiord, J.-y.; Grosso, R.; Guber, F.; Guernane, R.; Guerzoni, B.; Gulbrandsen, K.; Gulkanyan, H.; Gunji, T.; Gupta, A.; Gupta, R.; Haake, R.; Haaland, Ø.; Hadjidakis, C.; Haiduc, M.; Hamagaki, H.; Hamar, G.; Hanratty, L. D.; Hansen, A.; Harris, J. W.; Hartmann, H.; Harton, A.
2016-01-01
The production of (anti-)deuteron and (anti-)He 3 nuclei in Pb-Pb collisions at s NN − − − √ =2.76 TeV has been studied using the ALICE detector at the LHC. The spectra exhibit a significant hardening with increasing centrality. Combined blast-wave fits of several particles support the
Expected impact from weak reactions with light nuclei in corecollapse supernova simulations
Directory of Open Access Journals (Sweden)
Fischer T.
2016-01-01
Full Text Available We study the role of light nuclear clusters in simulations of core-collapse supernovae. Expressions for the reaction rates are developed for a large selection of charged current absorption and scattering processes with light clusters. Medium modifications are taken into account at the mean-field level. We explore the possible impact on the supernova dynamics and the neutrino signal during the mass accretion phase prior to the possible explosion onset as well as during the subsequent protoneutron star deleptnoization after the explosion onset has been launched.
CHROMATIN TEXTURE OF MELANOCYTIC NUCLEI - CORRELATION BETWEEN LIGHT AND ELECTRON-MICROSCOPY
ABMAYR, W; STOLZ, W; KORHERR, S; WILD, W; SCHMOECKEL, C
1987-01-01
Cells of a benign pigmented mole and a malignant melanoma were used to compare electron microscopy (EM) and light microscopy (LM) with high-resolution TV-scanning and multivariate analysis methods. Special emphasis was placed on different kinds of chromatin texture features and their discriminating
Shah, N.; Ma, Y. G.; Chen, J. H.; Zhang, S.
2016-03-01
The production of dibaryons, light nuclei and hypertriton in the most central Au+Au collisions at √{sNN} = 11.5 and 200 GeV is investigated by using a naive coalescence model. The production of light nuclei is studied and found that the production rate reduces by a factor of 330 (1200) for each extra nucleon added to nuclei at √{sNN} = 11.5 (200) GeV. The pT integrated yield of multistrange hadrons falls exponentially as strangeness quantum number increases. We further investigate strangeness population factors S3 ,S2 as a function of transverse momentum as well as √{sNN}. The calculations for √{sNN} = 11.5 GeV presented here will stimulate interest to carry out these measurements during the phase-II of beam energy scan program at STAR experiment.
Extension of the Li\\`ege Intranuclear-Cascade model to reactions induced by light nuclei
Mancusi, Davide; Cugnon, Joseph; David, Jean-Christophe; Kaitaniemi, Pekka; Leray, Sylvie
2014-01-01
The purpose of this paper is twofold. First, we present the extension of the Li\\`ege Intranuclear Cascade model to reactions induced by light ions. Second, we describe the C++ version of the code, which it is physics-wise equivalent to the legacy version, is available in Geant4 and will serve as the basis for all future development of the model. We describe the ideas upon which we built our treatment of nucleus-nucleus reactions and we compare the model predictions against a vast set of heterogeneous experimental data. In spite of the discussed limitations of the intranuclear-cascade scheme, we find that our model yields valid predictions for a number of observables and positions itself as one of the most attractive alternatives available to Geant4 users for the simulation of light-ion-induced reactions.
Measurement of light charged particles in the decay channels of medium-mass excited compound nuclei
Valdre', S; Casini, G; Pasquali, G; Piantelli, S; Carboni, S; Cinausero, M; Gramegna, F; Marchi, T; Baiocco, G; Bardelli, L; Benzoni, G; Bini, M; Blasi, N; Bracco, A; Brambilla, S; Bruno, M; Camera, F; Corsi, A; Crespi, F; Agostino, M D; Degerlier, M; Kravchuk, V L; Leoni, S; Million, B; Montanari, D; Morelli, L; Nannini, A; Nicolini, R; Poggi, G; Vannini, G; Wieland, O; Bednarczyk, P; Ciemała, M; Dudek, J; Fornal, B; Kmiecik, M; Maj, A; Matejska-Minda, M; Mazurek, K; Meczynski, W; Myalski, S; Styczen, J; Zieblinski, M
2013-01-01
The 48Ti on 40Ca reactions have been studied at 300 and 600 MeV focusing on the fusion-evaporation (FE) and fusion-fission (FF) exit channels. Energy spectra and multiplicities of the emitted light charged particles have been compared to Monte Carlo simulations based on the statistical model. Indeed, in this mass region (A about 100) models predict that shape transitions can occur at high spin values and relatively scarce data exist in the literature about coincidence measurements between evaporation residues and light charged particles. Signals of shape transitions can be found in the variations of the lineshape of high energy gamma rays emitted from the de-excitation of GDR states gated on different region of angular momenta. For this purpose it is important to keep under control the FE and FF processes, to regulate the statistical model parameters and to control the onset of possible preequilibrium emissions from 300 to 600 MeV bombarding energy.
Transfer reactions on light exotic nuclei studied with CHIMERA detector at LNS
Directory of Open Access Journals (Sweden)
Cardella Giuseppe
2014-03-01
Full Text Available The kinematical coincidence method is used to extract angular distribution of elastic scattering and transfer reactions. The detected light particle energy spectra are used to extract the angular distribution with around 1° resolution in the Center of Mass (CM system. Examples with 10Be beam are presented. In the case of proton scattering, γ-ray coincidences are used to discriminate excited levels population from elastic scattering.
Digital Repository Service at National Institute of Oceanography (India)
Gupta, S.M.
micronodules, crystalline aggregates of phillipsite, relic volcanic glass shards, and ichthyoliths (the phosphatic micro-remains of fishes) constitute the coarse fractions of these hard substrates and the nuclei. Alteration of volcanic material into palagonite...
Lee, Hyekyung; Baek, Tae Hwa; Park, Meeja; Lee, Seung Yun; Son, Hyun Jin; Kang, Dong Wook; Kim, Joo Heon; Kim, Soo Young
2016-01-01
Background There is subjective disagreement regarding nuclear clearing in papillary thyroid carcinoma. In this study, using digital instruments, we were able to quantify many ambiguous pathologic features and use numeric data to express our findings. Methods We examined 30 papillary thyroid carcinomas. For each case, we selected representative cancer cells showing clear nuclei and surrounding non-neoplastic follicular epithelial cells and evaluated objective values of green light intensity (GLI) for quantitative analysis of nuclear clearing in papillary thyroid carcinoma. Results From 16,274 GLI values from 600 cancer cell nuclei and 13,752 GLI values from 596 non-neoplastic follicular epithelial nuclei, we found a high correlation of 94.9% between GLI and clear nuclei. GLI between the cancer group showing clear nuclei and non-neoplastic follicular epithelia was statistically significant. The overall average level of GLI in the cancer group was over two times higher than the non-neoplastic group despite a wide range of GLI. On a polygonal line graph, there was a fluctuating unique difference between both the cancer and non-neoplastic groups in each patient, which was comparable to the microscopic findings. Conclusions Nuclear GLI could be a useful factor for discriminating between carcinoma cells showing clear nuclei and non-neoplastic follicular epithelia in papillary thyroid carcinoma. PMID:27550048
Measurement of light charged particles in the decay channels of medium-mass excited compound nuclei
Directory of Open Access Journals (Sweden)
Valdré S.
2014-03-01
Indeed, in this mass region (A ~ 100 models predict that shape transitions can occur at high spin values and relatively scarce data exist in the literature about coincidence measurements between evaporation residues and light charged particles. Signals of shape transitions can be found in the variations of the lineshape of high energy gamma rays emitted from the de-excitation of GDR states gated on different region of angular momenta. For this purpose it is important to keep under control the FE and FF processes, to regulate the statistical model parameters and to control the onset of possible pre-equilibrium emissions from 300 to 600 MeV bombarding energy.
Bystritsky, V. M.; Bystritsky, Vit. M.; Dudkin, G. N.; Nechaev, B. A.; Padalko, V. N.
2017-07-01
The factors defining the constraints on the current characteristics of the magnetically insulated ion diode (IDM) are considered. The specific current parameters close to the maximum possible ones are obtained for the particular IDM-40 design assigned for acceleration of light ions and investigation of nuclear reactions with small cross sections in the astrophysical energy range (2-40 keV) in the entrance channel. It is experimentally demonstrated that the chosen optimal operation conditions for IDM-40 units provide high stability of the parameters (energy distribution and composition of accelerated particle beams, degree of neutralization) of the accelerated particle flux, which increases during the working pulse.
Measurement of light charged particles in the decay channels of medium-mass excited compound nuclei
Valdré, S.; Barlini, S.; Casini, G.; Pasquali, G.; Piantelli, S.; Carboni, S.; Cinausero, M.; Gramegna, F.; Marchi, T.; Baiocco, G.; Bardelli, L.; Benzoni, G.; Bini, M.; Blasi, N.; Bracco, A.; Brambilla, S.; Bruno, M.; Camera, F.; Corsi, A.; Crespi, F.; D'Agostino, M.; Degerlier, M.; Kravchuk, V. L.; Leoni, S.; Million, B.; Montanari, D.; Morelli, L.; Nannini, A.; Nicolini, R.; Poggi, G.; Vannini, G.; Wieland, O.; Bednarczyk, P.; Ciemała, M.; Dudek, J.; Fornal, B.; Kmiecik, M.; Maj, A.; Matejska-Minda, M.; Mazurek, K.; Męczyński, W. M.; Myalski, S.; Styczeń, J.; Ziębliński, M.
2014-03-01
The 48Ti on 40Ca reactions have been studied at 300 and 600 MeV focusing on the fusion-evaporation (FE) and fusion-fission (FF) exit channels. Energy spectra and multiplicities of the emitted light charged particles have been compared to Monte Carlo simulations based on the statistical model. Indeed, in this mass region (A ~ 100) models predict that shape transitions can occur at high spin values and relatively scarce data exist in the literature about coincidence measurements between evaporation residues and light charged particles. Signals of shape transitions can be found in the variations of the lineshape of high energy gamma rays emitted from the de-excitation of GDR states gated on different region of angular momenta. For this purpose it is important to keep under control the FE and FF processes, to regulate the statistical model parameters and to control the onset of possible pre-equilibrium emissions from 300 to 600 MeV bombarding energy.
Fusion of light exotic nuclei at near-barrier energies: Effect of inelastic excitation
Indian Academy of Sciences (India)
P Banerjee; K Krishan; S Bhattacharya; C Bhattacharya
2003-09-01
The effect of inelastic excitation of exotic light projectiles (proton- as well as neutron-rich) 17F and 11Be on fusion with heavy target has been studied at near-barrier energies. The calculations have been performed in the coupled channels approach where, in addition to the normal coupling of the ground state of the projectile to the continuum, inelastic excitation of the projectile to the bound excited state and its coupling to the continuum have also been taken into consideration. The inclusion of these additional couplings has been found to have signiﬁcant effect on the fusion excitation function of neutron-rich 11Be on 208Pb whereas the effect has been observed to be nominal for the case of proton-rich 17F on the same target. The pronounced effect of the channel coupling on the fusion process in the case of 11Be is attributed to its well-developed halo structure.
Production of light flavor hadrons and anti-nuclei at the LHC
Kalweit, Alexander
With the recording of the first collisions of the Large Hadron Collider (LHC) in November 2009, a new era in the domain of high energy and relativistic heavy-ion physics has started. As one of the early observables which can be addressed, the measurement of light quark flavor production is presented in this thesis. Hadrons that consist only of u, d, and s quarks constitute the majority of the produced particles in pp and Pb–Pb collisions. Their measurement forms the basis for a detailed understanding of the collision and for the answer of the question if hadronic matter undergoes a phase transition to the deconfined quark-gluon plasma at high temperatures. The basics of ultra-relativistic heavy- ion physics are briefly introduced in the first chapter followed by a short description of the ALICE experiment. A particular focus is put on the unique particle identification (PID) capabilities as they provide the basis of the measurements which are presented in the following chapters. The particle identification ...
Pereira, J.; Montes, F.
2016-03-01
Background: Neutrino-driven winds following core-collapse supernova explosions have been proposed as a possible site where light r -process nuclei (between Fe and Ag) might be synthesized. In these events, (α ,n ) reactions are key to moving matter towards the region of higher proton number. Abundance network calculations are very sensitive to the rates for this type of reactions. Purpose: The present work aims at evaluating the theoretical uncertainty of these (α ,n ) reactions calculated with reaction codes based on the Hauser-Feshbach model. Method: We compared several (α ,n ) rates taken from talys and the non-smoker database to determine the uncertainties owing to the existing technical differences between both codes. In addition, we evaluated the sensitivity of talys rates to variations in the α optical potentials, masses, level densities, optical potentials, preequilibrium intranuclear transition rates, level structure, radiative transmission coefficients, and width-fluctuation correction factors. Results: The main source of uncertainty at low temperature is mostly attributable to the use of different α optical potentials. Differences between talys and non-smoker at high temperatures arise from the energy-binning algorithm used by each code. We have also noticed that the (α ,n ) rates from the non-smoker database correspond to the inclusive reaction, instead of the exclusive (α ,1 n ) channel calculated in the present work and used in network calculations. Conclusions: Theoretical uncertainties in calculated reaction rates can be as high as one to two orders of magnitude and strongly dependent on the temperature of the environment. Besides direct measurements of the inclusive and exclusive (α ,1 n ) reaction rates, experimental studies of α optical potentials are crucial to improve the performance of reaction codes.
Indian Academy of Sciences (India)
Arti Goyal; Mukul Mhaskey; Gopal-Krishna; Paul J. Wiita; C. S. Stalin; Ram Sagar
2013-09-01
It is important to quantify the underestimation of rms photometric errors returned by the commonly used APPHOT algorithm in the IRAF software, in the context of differential photometry of point-like AGN, because of the crucial role it plays in evaluating their variability properties. Published values of the underestimation factor, , using several different telescopes, lie in the range 1.3–1.75. The present study aims to revisit this question by employing an exceptionally large data set of 262 differential light curves (DLCs) derived from 262 pairs of non-varying stars monitored under our ARIES AGN monitoring program for characterizing the intra-night optical variability (INOV) of prominent AGN classes. The bulk of these data were taken with the 1-m Sampurnanad Telescope (ST). We find = 1.54 ± 0.05 which is close to our recently reported value of = 1.5. Moreover, this consistency holds at least up to a brightness mismatch of 1.5 mag between the paired stars. From this we infer that a magnitude difference of at least up to 1.5 mag between a point-like AGN and comparison star(s) monitored simultaneously is within the same CCD chip acceptable, as it should not lead to spurious claims of INOV.
Adam, Jaroslav; Aggarwal, Madan Mohan; Aglieri Rinella, Gianluca; Agnello, Michelangelo; Agrawal, Neelima; Ahammed, Zubayer; Ahmed, Ijaz; Ahn, Sang Un; Aimo, Ilaria; Aiola, Salvatore; Ajaz, Muhammad; Akindinov, Alexander; Alam, Sk Noor; Aleksandrov, Dmitry; Alessandro, Bruno; Alexandre, Didier; Alfaro Molina, Jose Ruben; Alici, Andrea; Alkin, Anton; Alme, Johan; Alt, Torsten; Altinpinar, Sedat; Altsybeev, Igor; Alves Garcia Prado, Caio; Andrei, Cristian; Andronic, Anton; Anguelov, Venelin; Anielski, Jonas; Anticic, Tome; Antinori, Federico; Antonioli, Pietro; Aphecetche, Laurent Bernard; Appelshaeuser, Harald; Arcelli, Silvia; Armesto Perez, Nestor; Arnaldi, Roberta; Aronsson, Tomas; Arsene, Ionut Cristian; Arslandok, Mesut; Augustinus, Andre; Averbeck, Ralf Peter; Azmi, Mohd Danish; Bach, Matthias Jakob; Badala, Angela; Baek, Yong Wook; Bagnasco, Stefano; Bailhache, Raphaelle Marie; Bala, Renu; Baldisseri, Alberto; Ball, Markus; Baltasar Dos Santos Pedrosa, Fernando; Baral, Rama Chandra; Barbano, Anastasia Maria; Barbera, Roberto; Barile, Francesco; Barnafoldi, Gergely Gabor; Barnby, Lee Stuart; Ramillien Barret, Valerie; Bartalini, Paolo; Bartke, Jerzy Gustaw; Bartsch, Esther; Basile, Maurizio; Bastid, Nicole; Basu, Sumit; Bathen, Bastian; Batigne, Guillaume; Batista Camejo, Arianna; Batyunya, Boris; Batzing, Paul Christoph; Bearden, Ian Gardner; Beck, Hans; Bedda, Cristina; Behera, Nirbhay Kumar; Belikov, Iouri; Bellini, Francesca; Bello Martinez, Hector; Bellwied, Rene; Belmont Iii, Ronald John; Belmont Moreno, Ernesto; Belyaev, Vladimir; Bencedi, Gyula; Beole, Stefania; Berceanu, Ionela; Bercuci, Alexandru; Berdnikov, Yaroslav; Berenyi, Daniel; Bertens, Redmer Alexander; Berzano, Dario; Betev, Latchezar; Bhasin, Anju; Bhat, Inayat Rasool; Bhati, Ashok Kumar; Bhattacharjee, Buddhadeb; Bhom, Jihyun; Bianchi, Livio; Bianchi, Nicola; Bianchin, Chiara; Bielcik, Jaroslav; Bielcikova, Jana; Bilandzic, Ante; Biswas, Saikat; Bjelogrlic, Sandro; Blanco, Fernando; Blau, Dmitry; Blume, Christoph; Bock, Friederike; Bogdanov, Alexey; Boggild, Hans; Boldizsar, Laszlo; Bombara, Marek; Book, Julian Heinz; Borel, Herve; Borissov, Alexander; Borri, Marcello; Bossu, Francesco; Botje, Michiel; Botta, Elena; Boettger, Stefan; Braun-Munzinger, Peter; Bregant, Marco; Breitner, Timo Gunther; Broker, Theo Alexander; Browning, Tyler Allen; Broz, Michal; Brucken, Erik Jens; Bruna, Elena; Bruno, Giuseppe Eugenio; Budnikov, Dmitry; Buesching, Henner; Bufalino, Stefania; Buncic, Predrag; Busch, Oliver; Buthelezi, Edith Zinhle; Buxton, Jesse Thomas; Caffarri, Davide; Cai, Xu; Caines, Helen Louise; Calero Diaz, Liliet; Caliva, Alberto; Calvo Villar, Ernesto; Camerini, Paolo; Carena, Francesco; Carena, Wisla; Castillo Castellanos, Javier Ernesto; Castro, Andrew John; Casula, Ester Anna Rita; Cavicchioli, Costanza; Ceballos Sanchez, Cesar; Cepila, Jan; Cerello, Piergiorgio; Chang, Beomsu; Chapeland, Sylvain; Chartier, Marielle; Charvet, Jean-Luc Fernand; Chattopadhyay, Subhasis; Chattopadhyay, Sukalyan; Chelnokov, Volodymyr; Cherney, Michael Gerard; Cheshkov, Cvetan Valeriev; Cheynis, Brigitte; Chibante Barroso, Vasco Miguel; Dobrigkeit Chinellato, David; Chochula, Peter; Choi, Kyungeon; Chojnacki, Marek; Choudhury, Subikash; Christakoglou, Panagiotis; Christensen, Christian Holm; Christiansen, Peter; Chujo, Tatsuya; Chung, Suh-Urk; Cicalo, Corrado; Cifarelli, Luisa; Cindolo, Federico; Cleymans, Jean Willy Andre; Colamaria, Fabio Filippo; Colella, Domenico; Collu, Alberto; Colocci, Manuel; Conesa Balbastre, Gustavo; Conesa Del Valle, Zaida; Connors, Megan Elizabeth; Contreras Nuno, Jesus Guillermo; Cormier, Thomas Michael; Corrales Morales, Yasser; Cortes Maldonado, Ismael; Cortese, Pietro; Cosentino, Mauro Rogerio; Costa, Filippo; Crochet, Philippe; Cruz Albino, Rigoberto; Cuautle Flores, Eleazar; Cunqueiro Mendez, Leticia; Dahms, Torsten; Dainese, Andrea; Danu, Andrea; Das, Debasish; Das, Indranil; Das, Supriya; Dash, Ajay Kumar; Dash, Sadhana; De, Sudipan; De Caro, Annalisa; De Cataldo, Giacinto; De Cuveland, Jan; De Falco, Alessandro; De Gruttola, Daniele; De Marco, Nora; De Pasquale, Salvatore; Deisting, Alexander; Deloff, Andrzej; Denes, Ervin Sandor; D'Erasmo, Ginevra; Di Bari, Domenico; Di Mauro, Antonio; Di Nezza, Pasquale; Diaz Corchero, Miguel Angel; Dietel, Thomas; Dillenseger, Pascal; Divia, Roberto; Djuvsland, Oeystein; Dobrin, Alexandru Florin; Dobrowolski, Tadeusz Antoni; Domenicis Gimenez, Diogenes; Donigus, Benjamin; Dordic, Olja; Dubey, Anand Kumar; Dubla, Andrea; Ducroux, Laurent; Dupieux, Pascal; Ehlers Iii, Raymond James; Elia, Domenico; Engel, Heiko; Erazmus, Barbara Ewa; Erhardt, Filip; Eschweiler, Dominic; Espagnon, Bruno; Estienne, Magali Danielle; Esumi, Shinichi; Eum, Jongsik; Evans, David; Evdokimov, Sergey; Eyyubova, Gyulnara; Fabbietti, Laura; Fabris, Daniela; Faivre, Julien; Fantoni, Alessandra; Fasel, Markus; Feldkamp, Linus; Felea, Daniel; Feliciello, Alessandro; Feofilov, Grigorii; Ferencei, Jozef; Fernandez Tellez, Arturo; Gonzalez Ferreiro, Elena; Ferretti, Alessandro; Festanti, Andrea; Figiel, Jan; Araujo Silva Figueredo, Marcel; Filchagin, Sergey; Finogeev, Dmitry; Fionda, Fiorella; Fiore, Enrichetta Maria; Fleck, Martin Gabriel; Floris, Michele; Foertsch, Siegfried Valentin; Foka, Panagiota; Fokin, Sergey; Fragiacomo, Enrico; Francescon, Andrea; Frankenfeld, Ulrich Michael; Fuchs, Ulrich; Furget, Christophe; Furs, Artur; Fusco Girard, Mario; Gaardhoeje, Jens Joergen; Gagliardi, Martino; Gago Medina, Alberto Martin; Gallio, Mauro; Gangadharan, Dhevan Raja; Ganoti, Paraskevi; Gao, Chaosong; Garabatos Cuadrado, Jose; Garcia-Solis, Edmundo Javier; Gargiulo, Corrado; Gasik, Piotr Jan; Germain, Marie; Gheata, Andrei George; Gheata, Mihaela; Ghosh, Premomoy; Ghosh, Sanjay Kumar; Gianotti, Paola; Giubellino, Paolo; Giubilato, Piero; Gladysz-Dziadus, Ewa; Glassel, Peter; Gomez Coral, Diego Mauricio; Gomez Ramirez, Andres; Gonzalez Zamora, Pedro; Gorbunov, Sergey; Gorlich, Lidia Maria; Gotovac, Sven; Grabski, Varlen; Graczykowski, Lukasz Kamil; Grelli, Alessandro; Grigoras, Alina Gabriela; Grigoras, Costin; Grigoryev, Vladislav; Grigoryan, Ara; Grigoryan, Smbat; Grynyov, Borys; Grion, Nevio; Grosse-Oetringhaus, Jan Fiete; Grossiord, Jean-Yves; Grosso, Raffaele; Guber, Fedor; Guernane, Rachid; Guerzoni, Barbara; Gulbrandsen, Kristjan Herlache; Gulkanyan, Hrant; Gunji, Taku; Gupta, Anik; Gupta, Ramni; Haake, Rudiger; Haaland, Oystein Senneset; Hadjidakis, Cynthia Marie; Haiduc, Maria; Hamagaki, Hideki; Hamar, Gergoe; Hanratty, Luke David; Hansen, Alexander; Harris, John William; Hartmann, Helvi; Harton, Austin Vincent; Hatzifotiadou, Despina; Hayashi, Shinichi; Heckel, Stefan Thomas; Heide, Markus Ansgar; Helstrup, Haavard; Herghelegiu, Andrei Ionut; Herrera Corral, Gerardo Antonio; Hess, Benjamin Andreas; Hetland, Kristin Fanebust; Hilden, Timo Eero; Hillemanns, Hartmut; Hippolyte, Boris; Hristov, Peter Zahariev; Huang, Meidana; Humanic, Thomas; Hussain, Nur; Hussain, Tahir; Hutter, Dirk; Hwang, Dae Sung; Ilkaev, Radiy; Ilkiv, Iryna; Inaba, Motoi; Ionita, Costin; Ippolitov, Mikhail; Irfan, Muhammad; Ivanov, Marian; Ivanov, Vladimir; Izucheev, Vladimir; Jacobs, Peter Martin; Jahnke, Cristiane; Jang, Haeng Jin; Janik, Malgorzata Anna; Pahula Hewage, Sandun; Jena, Chitrasen; Jena, Satyajit; Jimenez Bustamante, Raul Tonatiuh; Jones, Peter Graham; Jung, Hyungtaik; Jusko, Anton; Kalinak, Peter; Kalweit, Alexander Philipp; Kamin, Jason Adrian; Kang, Ju Hwan; Kaplin, Vladimir; Kar, Somnath; Karasu Uysal, Ayben; Karavichev, Oleg; Karavicheva, Tatiana; Karpechev, Evgeny; Kebschull, Udo Wolfgang; Keidel, Ralf; Keijdener, Darius Laurens; Keil, Markus; Khan, Kamal; Khan, Mohammed Mohisin; Khan, Palash; Khan, Shuaib Ahmad; Khanzadeev, Alexei; Kharlov, Yury; Kileng, Bjarte; Kim, Beomkyu; Kim, Do Won; Kim, Dong Jo; Kim, Hyeonjoong; Kim, Jinsook; Kim, Mimae; Kim, Minwoo; Kim, Se Yong; Kim, Taesoo; Kirsch, Stefan; Kisel, Ivan; Kiselev, Sergey; Kisiel, Adam Ryszard; Kiss, Gabor; Klay, Jennifer Lynn; Klein, Carsten; Klein, Jochen; Klein-Boesing, Christian; Kluge, Alexander; Knichel, Michael Linus; Knospe, Anders Garritt; Kobayashi, Taiyo; Kobdaj, Chinorat; Kofarago, Monika; Kohler, Markus Konrad; Kollegger, Thorsten; Kolozhvari, Anatoly; Kondratev, Valerii; Kondratyeva, Natalia; Kondratyuk, Evgeny; Konevskikh, Artem; Kour, Mandeep; Kouzinopoulos, Charalampos; Kovalenko, Oleksandr; Kovalenko, Vladimir; Kowalski, Marek; Kox, Serge; Koyithatta Meethaleveedu, Greeshma; Kral, Jiri; Kralik, Ivan; Kravcakova, Adela; Krelina, Michal; Kretz, Matthias; Krivda, Marian; Krizek, Filip; Kryshen, Evgeny; Krzewicki, Mikolaj; Kubera, Andrew Michael; Kucera, Vit; Kucheryaev, Yury; Kugathasan, Thanushan; Kuhn, Christian Claude; Kuijer, Paulus Gerardus; Kulakov, Igor; Kumar, Ajay; Kumar, Jitendra; Lokesh, Kumar; Kurashvili, Podist; Kurepin, Alexander; Kurepin, Alexey; Kuryakin, Alexey; Kushpil, Svetlana; Kweon, Min Jung; Kwon, Youngil; La Pointe, Sarah Louise; La Rocca, Paola; Lagana Fernandes, Caio; Lakomov, Igor; Langoy, Rune; Lara Martinez, Camilo Ernesto; Lardeux, Antoine Xavier; Lattuca, Alessandra; Laudi, Elisa; Lea, Ramona; Leardini, Lucia; Lee, Graham Richard; Lee, Seongjoo; Legrand, Iosif; Lehnert, Joerg Walter; Lemmon, Roy Crawford; Lenti, Vito; Leogrande, Emilia; Leon Monzon, Ildefonso; Leoncino, Marco; Levai, Peter; Li, Shuang; Li, Xiaomei; Lien, Jorgen Andre; Lietava, Roman; Lindal, Svein; Lindenstruth, Volker; Lippmann, Christian; Lisa, Michael Annan; Ljunggren, Hans Martin; Lodato, Davide Francesco; Lonne, Per-Ivar; Loggins, Vera Renee; Loginov, Vitaly; Loizides, Constantinos; Lopez, Xavier Bernard; Lopez Torres, Ernesto; Lowe, Andrew John; Lu, Xianguo; Luettig, Philipp Johannes; Lunardon, Marcello; Luparello, Grazia; Maevskaya, Alla; Mager, Magnus; Mahajan, Sanjay; Mahmood, Sohail Musa; Maire, Antonin; Majka, Richard Daniel; Malaev, Mikhail; Maldonado Cervantes, Ivonne Alicia; Malinina, Liudmila; Mal'Kevich, Dmitry; Malzacher, Peter; Mamonov, Alexander; Manceau, Loic Henri Antoine; Manko, Vladislav; Manso, Franck; Manzari, Vito; Marchisone, Massimiliano; Mares, Jiri; Margagliotti, Giacomo Vito; Margotti, Anselmo; Margutti, Jacopo; Marin, Ana Maria; Markert, Christina; Marquard, Marco; Martin, Nicole Alice; Martin Blanco, Javier; Martinengo, Paolo; Martinez Hernandez, Mario Ivan; Martinez-Garcia, Gines; Martinez Pedreira, Miguel; Martynov, Yevgen; Mas, Alexis Jean-Michel; Masciocchi, Silvia; Masera, Massimo; Masoni, Alberto; Massacrier, Laure Marie; Mastroserio, Annalisa; Masui, Hiroshi; Matyja, Adam Tomasz; Mayer, Christoph; Mazer, Joel Anthony; Mazzoni, Alessandra Maria; Mcdonald, Daniel; Meddi, Franco; Menchaca-Rocha, Arturo Alejandro; Meninno, Elisa; Mercado-Perez, Jorge; Meres, Michal; Miake, Yasuo; Mieskolainen, Matti Mikael; Mikhaylov, Konstantin; Milano, Leonardo; Milosevic, Jovan; Minervini, Lazzaro Manlio; Mischke, Andre; Mishra, Aditya Nath; Miskowiec, Dariusz Czeslaw; Mitra, Jubin; Mitu, Ciprian Mihai; Mohammadi, Naghmeh; Mohanty, Bedangadas; Molnar, Levente; Montano Zetina, Luis Manuel; Montes Prado, Esther; Morando, Maurizio; Moreira De Godoy, Denise Aparecida; Perez Moreno, Luis Alberto; Moretto, Sandra; Morreale, Astrid; Morsch, Andreas; Muccifora, Valeria; Mudnic, Eugen; Muhlheim, Daniel Michael; Muhuri, Sanjib; Mukherjee, Maitreyee; Muller, Hans; Mulligan, James Declan; Gameiro Munhoz, Marcelo; Murray, Sean; Musa, Luciano; Musinsky, Jan; Nandi, Basanta Kumar; Nania, Rosario; Nappi, Eugenio; Naru, Muhammad Umair; Nattrass, Christine; Nayak, Kishora; Nayak, Tapan Kumar; Nazarenko, Sergey; Nedosekin, Alexander; Nellen, Lukas; Ng, Fabian; Nicassio, Maria; Niculescu, Mihai; Niedziela, Jeremi; Nielsen, Borge Svane; Nikolaev, Sergey; Nikulin, Sergey; Nikulin, Vladimir; Noferini, Francesco; Nomokonov, Petr; Nooren, Gerardus; Norman, Jaime; Nyanin, Alexander; Nystrand, Joakim Ingemar; Oeschler, Helmut Oskar; Oh, Saehanseul; Oh, Sun Kun; Ohlson, Alice Elisabeth; Okatan, Ali; Okubo, Tsubasa; Olah, Laszlo; Oleniacz, Janusz; Oliveira Da Silva, Antonio Carlos; Oliver, Michael Henry; Onderwaater, Jacobus; Oppedisano, Chiara; Ortiz Velasquez, Antonio; Oskarsson, Anders Nils Erik; Otwinowski, Jacek Tomasz; Oyama, Ken; Ozdemir, Mahmut; Pachmayer, Yvonne Chiara; Pagano, Paola; Paic, Guy; Pajares Vales, Carlos; Pal, Susanta Kumar; Pan, Jinjin; Pandey, Ashutosh Kumar; Pant, Divyash; Papikyan, Vardanush; Pappalardo, Giuseppe; Pareek, Pooja; Park, Woojin; Parmar, Sonia; Passfeld, Annika; Paticchio, Vincenzo; Paul, Biswarup; Pawlak, Tomasz Jan; Peitzmann, Thomas; Pereira Da Costa, Hugo Denis Antonio; Pereira De Oliveira Filho, Elienos; Peresunko, Dmitry Yurevich; Perez Lara, Carlos Eugenio; Peskov, Vladimir; Pestov, Yury; Petracek, Vojtech; Petrov, Viacheslav; Petrovici, Mihai; Petta, Catia; Piano, Stefano; Pikna, Miroslav; Pillot, Philippe; Pinazza, Ombretta; Pinsky, Lawrence; Piyarathna, Danthasinghe; Ploskon, Mateusz Andrzej; Planinic, Mirko; Pluta, Jan Marian; Pochybova, Sona; Podesta Lerma, Pedro Luis Manuel; Poghosyan, Martin; Polishchuk, Boris; Poljak, Nikola; Poonsawat, Wanchaloem; Pop, Amalia; Porteboeuf, Sarah Julie; Porter, R Jefferson; Pospisil, Jan; Prasad, Sidharth Kumar; Preghenella, Roberto; Prino, Francesco; Pruneau, Claude Andre; Pshenichnov, Igor; Puccio, Maximiliano; Puddu, Giovanna; Pujahari, Prabhat Ranjan; Punin, Valery; Putschke, Jorn Henning; Qvigstad, Henrik; Rachevski, Alexandre; Raha, Sibaji; Rajput, Sonia; Rak, Jan; Rakotozafindrabe, Andry Malala; Ramello, Luciano; Raniwala, Rashmi; Raniwala, Sudhir; Rasanen, Sami Sakari; Rascanu, Bogdan Theodor; Rathee, Deepika; Read, Kenneth Francis; Real, Jean-Sebastien; Redlich, Krzysztof; Reed, Rosi Jan; Rehman, Attiq Ur; Reichelt, Patrick Simon; Reicher, Martijn; Reidt, Felix; Ren, Xiaowen; Renfordt, Rainer Arno Ernst; Reolon, Anna Rita; Reshetin, Andrey; Rettig, Felix Vincenz; Revol, Jean-Pierre; Reygers, Klaus Johannes; Riabov, Viktor; Ricci, Renato Angelo; Richert, Tuva Ora Herenui; Richter, Matthias Rudolph; Riedler, Petra; Riegler, Werner; Riggi, Francesco; Ristea, Catalin-Lucian; Rivetti, Angelo; Rocco, Elena; Rodriguez Cahuantzi, Mario; Rodriguez Manso, Alis; Roeed, Ketil; Rogochaya, Elena; Rohr, David Michael; Roehrich, Dieter; Romita, Rosa; Ronchetti, Federico; Ronflette, Lucile; Rosnet, Philippe; Rossi, Andrea; Roukoutakis, Filimon; Roy, Ankhi; Roy, Christelle Sophie; Roy, Pradip Kumar; Rubio Montero, Antonio Juan; Rui, Rinaldo; Russo, Riccardo; Ryabinkin, Evgeny; Ryabov, Yury; Rybicki, Andrzej; Sadovskiy, Sergey; Safarik, Karel; Sahlmuller, Baldo; Sahoo, Pragati; Sahoo, Raghunath; Sahoo, Sarita; Sahu, Pradip Kumar; Saini, Jogender; Sakai, Shingo; Saleh, Mohammad Ahmad; Salgado Lopez, Carlos Alberto; Salzwedel, Jai Samuel Nielsen; Sambyal, Sanjeev Singh; Samsonov, Vladimir; Sanchez Castro, Xitzel; Sandor, Ladislav; Sandoval, Andres; Sano, Masato; Santagati, Gianluca; Sarkar, Debojit; Scapparone, Eugenio; Scarlassara, Fernando; Scharenberg, Rolf Paul; Schiaua, Claudiu Cornel; Schicker, Rainer Martin; Schmidt, Christian Joachim; Schmidt, Hans Rudolf; Schuchmann, Simone; Schukraft, Jurgen; Schulc, Martin; Schuster, Tim Robin; Schutz, Yves Roland; Schwarz, Kilian Eberhard; Schweda, Kai Oliver; Scioli, Gilda; Scomparin, Enrico; Scott, Rebecca Michelle; Seeder, Karin Soraya; Seger, Janet Elizabeth; Sekiguchi, Yuko; Selyuzhenkov, Ilya; Senosi, Kgotlaesele; Seo, Jeewon; Serradilla Rodriguez, Eulogio; Sevcenco, Adrian; Shabanov, Arseniy; Shabetai, Alexandre; Shadura, Oksana; Shahoyan, Ruben; Shangaraev, Artem; Sharma, Ankita; Sharma, Monika; Sharma, Natasha; Shigaki, Kenta; Shtejer Diaz, Katherin; Sibiryak, Yury; Siddhanta, Sabyasachi; Sielewicz, Krzysztof Marek; Siemiarczuk, Teodor; Silvermyr, David Olle Rickard; Silvestre, Catherine Micaela; Simatovic, Goran; Simonetti, Giuseppe; Singaraju, Rama Narayana; Singh, Ranbir; Singha, Subhash; Singhal, Vikas; Sinha, Bikash; Sarkar - Sinha, Tinku; Sitar, Branislav; Sitta, Mario; Skaali, Bernhard; Slupecki, Maciej; Smirnov, Nikolai; Snellings, Raimond; Snellman, Tomas Wilhelm; Soegaard, Carsten; Soltz, Ron Ariel; Song, Jihye; Song, Myunggeun; Song, Zixuan; Soramel, Francesca; Sorensen, Soren Pontoppidan; Spacek, Michal; Spiriti, Eleuterio; Sputowska, Iwona Anna; Spyropoulou-Stassinaki, Martha; Srivastava, Brijesh Kumar; Stachel, Johanna; Stan, Ionel; Stefanek, Grzegorz; Steinpreis, Matthew Donald; Stenlund, Evert Anders; Steyn, Gideon Francois; Stiller, Johannes Hendrik; Stocco, Diego; Strmen, Peter; Alarcon Do Passo Suaide, Alexandre; Sugitate, Toru; Suire, Christophe Pierre; Suleymanov, Mais Kazim Oglu; Sultanov, Rishat; Sumbera, Michal; Symons, Timothy; Szabo, Alexander; Szanto De Toledo, Alejandro; Szarka, Imrich; Szczepankiewicz, Adam; Szymanski, Maciej Pawel; Takahashi, Jun; Tanaka, Naoto; Tangaro, Marco-Antonio; Tapia Takaki, Daniel Jesus; Tarantola Peloni, Attilio; Tariq, Mohammad; Tarzila, Madalina-Gabriela; Tauro, Arturo; Tejeda Munoz, Guillermo; Telesca, Adriana; Terasaki, Kohei; Terrevoli, Cristina; Teyssier, Boris; Thaeder, Jochen Mathias; Thomas, Deepa; Tieulent, Raphael Noel; Timmins, Anthony Robert; Toia, Alberica; Trogolo, Stefano; Trubnikov, Victor; Trzaska, Wladyslaw Henryk; Tsuji, Tomoya; Tumkin, Alexandr; Turrisi, Rosario; Tveter, Trine Spedstad; Ullaland, Kjetil; Uras, Antonio; Usai, Gianluca; Utrobicic, Antonija; Vajzer, Michal; Vala, Martin; Valencia Palomo, Lizardo; Vallero, Sara; Van Der Maarel, Jasper; Van Hoorne, Jacobus Willem; Van Leeuwen, Marco; Vanat, Tomas; Vande Vyvre, Pierre; Varga, Dezso; Diozcora Vargas Trevino, Aurora; Vargyas, Marton; Varma, Raghava; Vasileiou, Maria; Vasiliev, Andrey; Vauthier, Astrid; Vechernin, Vladimir; Veen, Annelies Marianne; Veldhoen, Misha; Velure, Arild; Venaruzzo, Massimo; Vercellin, Ermanno; Vergara Limon, Sergio; Vernet, Renaud; Verweij, Marta; Vickovic, Linda; Viesti, Giuseppe; Viinikainen, Jussi Samuli; Vilakazi, Zabulon; Villalobos Baillie, Orlando; Villatoro Tello, Abraham; Vinogradov, Alexander; Vinogradov, Leonid; Vinogradov, Yury; Virgili, Tiziano; Vislavicius, Vytautas; Viyogi, Yogendra; Vodopyanov, Alexander; Volkl, Martin Andreas; Voloshin, Kirill; Voloshin, Sergey; Volpe, Giacomo; Von Haller, Barthelemy; Vorobyev, Ivan; Vranic, Danilo; Vrlakova, Janka; Vulpescu, Bogdan; Vyushin, Alexey; Wagner, Boris; Wagner, Jan; Wang, Hongkai; Wang, Mengliang; Wang, Yifei; Watanabe, Daisuke; Weber, Michael; Weber, Steffen Georg; Wessels, Johannes Peter; Westerhoff, Uwe; Wiechula, Jens; Wikne, Jon; Wilde, Martin Rudolf; Wilk, Grzegorz Andrzej; Wilkinson, Jeremy John; Williams, Crispin; Windelband, Bernd Stefan; Winn, Michael Andreas; Yaldo, Chris G; Yamaguchi, Yorito; Yang, Hongyan; Yang, Ping; Yano, Satoshi; Yasnopolskiy, Stanislav; Yin, Zhongbao; Yokoyama, Hiroki; Yoo, In-Kwon; Yurchenko, Volodymyr; Yushmanov, Igor; Zaborowska, Anna; Zaccolo, Valentina; Zaman, Ali; Zampolli, Chiara; Correia Zanoli, Henrique Jose; Zaporozhets, Sergey; Zarochentsev, Andrey; Zavada, Petr; Zavyalov, Nikolay; Zbroszczyk, Hanna Paulina; Zgura, Sorin Ion; Zhalov, Mikhail; Zhang, Haitao; Zhang, Xiaoming; Zhang, Yonghong; Zhao, Chengxin; Zhigareva, Natalia; Zhou, Daicui; Zhou, You; Zhou, Zhuo; Zhu, Hongsheng; Zhu, Jianhui; Zhu, Xiangrong; Zichichi, Antonino; Zimmermann, Alice; Zimmermann, Markus Bernhard; Zinovjev, Gennady; Zyzak, Maksym
2016-02-29
The production of (anti-)deuteron and (anti-)$^{3}$He nuclei in Pb-Pb collisions at $\\sqrt{s_{\\rm NN}}$ = 2.76 TeV has been studied using the ALICE detector at the LHC. The spectra exhibit a significant hardening with increasing centrality. Combined blast-wave fits of several particles support the interpretation that this behavior is caused by an increase of radial flow. The integrated particle yields are discussed in the context of coalescence and thermal-statistical model expectations. The particle ratios, $^3$He/d and $^3$He/p, in Pb-Pb collisions are found to be in agreement with a common chemical freeze-out temperature of $T_{\\rm chem} \\approx 156$ MeV. These ratios do not vary with centrality which is in agreement with the thermal-statistical model. In a coalescence approach, it excludes models in which nucleus production is proportional to the particle multiplicity and favors those in which it is proportional to the particle density instead. In addition, the observation of 31 anti-tritons in Pb-Pb coll...
Adamczyk, L; Agakishiev, G; Aggarwal, M M; Ahammed, Z; Alekseev, I; Aparin, A; Arkhipkin, D; Aschenauer, E C; Ashraf, M U; Attri, A; Averichev, G S; Bai, X; Bairathi, V; Bellwied, R; Bhasin, A; Bhati, A K; Bhattarai, P; Bielcik, J; Bielcikova, J; Bland, L C; Bordyuzhin, I G; Bouchet, J; Brandenburg, J D; Brandin, A V; Bunzarov, I; Butterworth, J; Caines, H; Sánchez, M Calderón de la Barca; Campbell, J M; Cebra, D; Chakaberia, I; Chaloupka, P; Chang, Z; Chatterjee, A; Chattopadhyay, S; Chen, X; Chen, J H; Cheng, J; Cherney, M; Christie, W; Contin, G; Crawford, H J; Das, S; De Silva, L C; Debbe, R R; Dedovich, T G; Deng, J; Derevschikov, A A; di Ruzza, B; Didenko, L; Dilks, C; Dong, X; Drachenberg, J L; Draper, J E; Du, C M; Dunkelberger, L E; Dunlop, J C; Efimov, L G; Engelage, J; Eppley, G; Esha, R; Evdokimov, O; Eyser, O; Fatemi, R; Fazio, S; Federic, P; Fedorisin, J; Feng, Z; Filip, P; Fisyak, Y; Flores, C E; Fulek, L; Gagliardi, C A; Garand, D; Geurts, F; Gibson, A; Girard, M; Greiner, L; Grosnick, D; Gunarathne, D S; Guo, Y; Gupta, S; Gupta, A; Guryn, W; Hamad, A I; Hamed, A; Haque, R; Harris, J W; He, L; Heppelmann, S; Hirsch, A; Hoffmann, G W; Horvat, S; Huang, T; Huang, H Z; Huang, X; Huang, B; Huck, P; Humanic, T J; Igo, G; Jacobs, W W; Jang, H; Jentsch, A; Jia, J; Jiang, K; Judd, E G; Kabana, S; Kalinkin, D; Kang, K; Kauder, K; Ke, H W; Keane, D; Kechechyan, A; Khan, Z H; Kikoła, D P; Kisel, I; Kisiel, A; Kochenda, L; Koetke, D D; Kosarzewski, L K; Kraishan, A F; Kravtsov, P; Krueger, K; Kumar, L; Lamont, M A C; Landgraf, J M; Landry, K D; Lauret, J; Lebedev, A; Lednicky, R; Lee, J H; Li, W; Li, X; Li, C; Li, Y; Lin, T; Lisa, M A; Liu, F; Ljubicic, T; Llope, W J; Lomnitz, M; Longacre, R S; Luo, X; Ma, G L; Ma, R; Ma, Y G; Ma, L; Magdy, N; Majka, R; Manion, A; Margetis, S; Markert, C; Matis, H S; McDonald, D; McKinzie, S; Meehan, K; Mei, J C; Minaev, N G; Mioduszewski, S; Mishra, D; Mohanty, B; Mondal, M M; Morozov, D A; Mustafa, M K; Nandi, B K; Nasim, Md; Nayak, T K; Nigmatkulov, G; Niida, T; Nogach, L V; Noh, S Y; Novak, J; Nurushev, S B; Odyniec, G; Ogawa, A; Oh, K; Okorokov, V A; Olvitt, D; Page, B S; Pak, R; Pan, Y X; Pandit, Y; Panebratsev, Y; Pawlik, B; Pei, H; Perkins, C; Pile, P; Pluta, J; Poniatowska, K; Porter, J; Posik, M; Poskanzer, A M; Pruthi, N K; Putschke, J; Qiu, H; Quintero, A; Ramachandran, S; Raniwala, S; Raniwala, R; Ray, R L; Ritter, H G; Roberts, J B; Rogachevskiy, O V; Romero, J L; Ruan, L; Rusnak, J; Rusnakova, O; Sahoo, N R; Sahu, P K; Sakrejda, I; Salur, S; Sandweiss, J; Sarkar, A; Schambach, J; Scharenberg, R P; Schmah, A M; Schmidke, W B; Schmitz, N; Seger, J; Seyboth, P; Shah, N; Shahaliev, E; Shanmuganathan, P V; Shao, M; Sharma, B; Sharma, A; Sharma, M K; Shen, W Q; Shi, Z; Shi, S S; Shou, Q Y; Sichtermann, E P; Sikora, R; Simko, M; Singha, S; Skoby, M J; Smirnov, D; Smirnov, N; Solyst, W; Song, L; Sorensen, P; Spinka, H M; Srivastava, B; Stanislaus, T D S; Stepanov, M; Stock, R; Strikhanov, M; Stringfellow, B; Sumbera, M; Summa, B; Sun, Y; Sun, X M; Sun, Z; Surrow, B; Svirida, D N; Tang, Z; Tang, A H; Tarnowsky, T; Tawfik, A; Thäder, J; Thomas, J H; Timmins, A R; Tlusty, D; Todoroki, T; Tokarev, M; Trentalange, S; Tribble, R E; Tribedy, P; Tripathy, S K; Tsai, O D; Ullrich, T; Underwood, D G; Upsal, I; Van Buren, G; van Nieuwenhuizen, G; Vandenbroucke, M; Varma, R; Vasiliev, A N; Vertesi, R; Videbæk, F; Vokal, S; Voloshin, S A; Vossen, A; Wang, H; Wang, J S; Wang, Y; Wang, F; Wang, G; Webb, G; Webb, J C; Wen, L; Westfall, G D; Wieman, H; Wissink, S W; Witt, R; Wu, Y; Xiao, Z G; Xie, G; Xie, W; Xin, K; Xu, N; Xu, H; Xu, Z; Xu, Y F; Xu, J; Xu, Q H; Yang, C; Yang, Y; Yang, S; Yang, Q; Ye, Z; Yepes, P; Yi, L; Yip, K; Yoo, I -K; Yu, N; Zbroszczyk, H; Zha, W; Zhang, J B; Zhang, J; Zhang, Z; Zhang, S; Zhang, Y; Zhang, X P; Zhao, J; Zhong, C; Zhou, L; Zhu, X; Zoulkarneeva, Y; Zyzak, M
2016-01-01
We present measurements of 2$^{nd}$ order azimuthal anisotropy ($v_{2}$) at mid-rapidity $(|y|<1.0)$ for light nuclei d, t, $^{3}$He (for $\\sqrt{s_{NN}}$ = 200, 62.4, 39, 27, 19.6, 11.5, and 7.7 GeV) and anti-nuclei $\\bar{\\rm d}$ ($\\sqrt{s_{NN}}$ = 200, 62.4, 39, 27, and 19.6 GeV) and $^{3}\\bar{\\rm He}$ ($\\sqrt{s_{NN}}$ = 200 GeV) in the STAR (Solenoidal Tracker at RHIC) experiment. The $v_{2}$ for these light nuclei produced in heavy-ion collisions is compared with those for p and $\\bar{\\rm p}$. We observe mass ordering in nuclei $v_{2}(p_{T})$ at low transverse momenta ($p_{T}<2.0$ GeV/$c$). We also find a centrality dependence of $v_{2}$ for d and $\\bar{\\rm d}$. The magnitude of $v_{2}$ for t and $^{3}$He agree within statistical errors. Light-nuclei $v_{2}$ are compared with predictions from a blast wave model. Atomic mass number ($A$) scaling of light-nuclei $v_{2}(p_{T})$ seems to hold for $p_{T}/A < 1.5$ GeV/$c$. Results on light-nuclei $v_{2}$ from a transport-plus-coalescence model are consi...
Shah, N; Chen, J H; Zhang, and S
2015-01-01
The production of dibaryons, light nuclei and hypertriton in the most central Au+Au collisions at $\\sqrt{s_{NN}}=$ 11.5 and 200 GeV are investigated by using a naive coalescence model. The production of light nuclei is studied and found that the production rate reduces by a factor of 330 (1200) for each extra nucleon added to nuclei at $\\sqrt{s_{NN}}=$ 11.5 (200) GeV. The $p_{T}$ integrated yield of multistrange hadrons falls exponentially as strangeness quantum number increases. We further investigate strangeness population factor $S_{3}, S_{2}$ as a function of transverse momentum as well as $\\sqrt{s_{NN}}$. The baryon-strangeness correlation coefficient $C_{BS}$ is also investigated for $\\sqrt{s_{NN}}=$ 11.5 and 200 GeV. The calculations for $\\sqrt{s_{NN}}=$ 11.5 GeV presented here will stimulate interest to carry out these measurements during the phase-II of beam energy scan program at STAR experiment.
Energy Technology Data Exchange (ETDEWEB)
Normand, G
2004-10-01
Correlations play a crucial role in understanding the structure of light nuclei at and beyond the neutron drip-line. In this context, the two-neutron halo nucleus He{sup 6} and the unbound systems H{sup 5}, He{sup 7,9} and Li{sup 10} have been studied via measurements of the breakup of beams of He{sup 6} and Be{sup 11,12}. The CHARISSA and DEMON detector arrays were employed. The interpretation was facilitated by a simulation code (SILLAGE) which provided for the setup. In the case of He{sup 7}, the existence of an excited state with E{sub r} {approx} 1 MeV and gamma {approx} 0.75 MeV was confirmed. The virtual character of the s-wave ground state of Li{sup 10} was also confirmed and a scattering length of as {approx} -16 fm deduced. The results obtained for He{sup 9} suggest that a virtual s-wave state may exist just above threshold. The study of the three-body breakup of He{sup 6} found that the decay of the first 2+ state is essentially direct, while the decay of the remaining continuum strength is sequential - passage via He{sup 5}. Using the technique of intensity interferometry an rms separation between the halo neutrons of 7.7 +- 0.8 fm was derived. This result was confirmed by a complementary method utilizing Dalitz plots. In the case of H{sup 5}, the invariant mass spectrum was found to exhibit a broad (gamma {approx} 2 MeV) structure some 1.8 MeV above threshold. Comparison with recent three-body model calculations suggest that this corresponds to the predicted 1/2+ ground state. An rms valence neutron separation of some 5.5 fm was estimated. A search was also carried out for the 4n system using the Be{sup 12*} (2 alpha + Xn decay channel). No signal was observed beyond that expected on the basis of the known background processes. (author)
Lupu, Sergiu; Gazit, Doron
2015-01-01
The large nucleon-nucleon scattering length, and the isospin approximate symmetry, are low energy properties of quantum chromodynamics (QCD). These entail correlations in the binding energies of light nuclei, e.g., the A=3 iso-multiplet, and Tjon's correlation between the binding energy of three and four body nuclei. Using a new representation of these, we establish that they translate into a correlation between different short-range contributions to three body forces in chiral effective field theory of low-energy nuclear physics. We demonstrate that these correlations should be taken into account in order to avoid fine-tuning in the calibration of three body forces. We relate this to the role of correlations in uncertainty quantification of non-renormalizable effective field theories of the nuclear regime. In addition, we show that correlations can be useful in assessing the importance of forces induced by renormalization group (RG) transformations. We give numerical evidence that such RG transformations can...
Directory of Open Access Journals (Sweden)
Huibing Hao
2015-01-01
Full Text Available Light emitting diode (LED lamp has attracted increasing interest in the field of lighting systems due to its low energy and long lifetime. For different functions (i.e., illumination and color, it may have two or more performance characteristics. When the multiple performance characteristics are dependent, it creates a challenging problem to accurately analyze the system reliability. In this paper, we assume that the system has two performance characteristics, and each performance characteristic is governed by a random effects Gamma process where the random effects can capture the unit to unit differences. The dependency of performance characteristics is described by a Frank copula function. Via the copula function, the reliability assessment model is proposed. Considering the model is so complicated and analytically intractable, the Markov chain Monte Carlo (MCMC method is used to estimate the unknown parameters. A numerical example about actual LED lamps data is given to demonstrate the usefulness and validity of the proposed model and method.
A Machine Learning Method to Infer Fundamental Stellar Parameters from Photometric Light Curves
Miller, A A; Richards, J W; Lee, Y S; Starr, D L; Butler, N R; Tokarz, S; Smith, N; Eisner, J A
2014-01-01
A fundamental challenge for wide-field imaging surveys is obtaining follow-up spectroscopic observations: there are > $10^9$ photometrically cataloged sources, yet modern spectroscopic surveys are limited to ~few x $10^6$ targets. As we approach the Large Synoptic Survey Telescope (LSST) era, new algorithmic solutions are required to cope with the data deluge. Here we report the development of a machine-learning framework capable of inferring fundamental stellar parameters (Teff, log g, and [Fe/H]) using photometric-brightness variations and color alone. A training set is constructed from a systematic spectroscopic survey of variables with Hectospec/MMT. In sum, the training set includes ~9000 spectra, for which stellar parameters are measured using the SEGUE Stellar Parameters Pipeline (SSPP). We employed the random forest algorithm to perform a non-parametric regression that predicts Teff, log g, and [Fe/H] from photometric time-domain observations. Our final, optimized model produces a cross-validated root...
A MACHINE-LEARNING METHOD TO INFER FUNDAMENTAL STELLAR PARAMETERS FROM PHOTOMETRIC LIGHT CURVES
Energy Technology Data Exchange (ETDEWEB)
Miller, A. A. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, MS 169-506, Pasadena, CA 91109 (United States); Bloom, J. S.; Richards, J. W.; Starr, D. L. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Lee, Y. S. [Department of Astronomy and Space Science, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Butler, N. R. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85281 (United States); Tokarz, S. [Smithsonian Astrophysical Observatory, Cambridge, MA 02138 (United States); Smith, N.; Eisner, J. A., E-mail: amiller@astro.caltech.edu [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States)
2015-01-10
A fundamental challenge for wide-field imaging surveys is obtaining follow-up spectroscopic observations: there are >10{sup 9} photometrically cataloged sources, yet modern spectroscopic surveys are limited to ∼few× 10{sup 6} targets. As we approach the Large Synoptic Survey Telescope era, new algorithmic solutions are required to cope with the data deluge. Here we report the development of a machine-learning framework capable of inferring fundamental stellar parameters (T {sub eff}, log g, and [Fe/H]) using photometric-brightness variations and color alone. A training set is constructed from a systematic spectroscopic survey of variables with Hectospec/Multi-Mirror Telescope. In sum, the training set includes ∼9000 spectra, for which stellar parameters are measured using the SEGUE Stellar Parameters Pipeline (SSPP). We employed the random forest algorithm to perform a non-parametric regression that predicts T {sub eff}, log g, and [Fe/H] from photometric time-domain observations. Our final optimized model produces a cross-validated rms error (RMSE) of 165 K, 0.39 dex, and 0.33 dex for T {sub eff}, log g, and [Fe/H], respectively. Examining the subset of sources for which the SSPP measurements are most reliable, the RMSE reduces to 125 K, 0.37 dex, and 0.27 dex, respectively, comparable to what is achievable via low-resolution spectroscopy. For variable stars this represents a ≈12%-20% improvement in RMSE relative to models trained with single-epoch photometric colors. As an application of our method, we estimate stellar parameters for ∼54,000 known variables. We argue that this method may convert photometric time-domain surveys into pseudo-spectrographic engines, enabling the construction of extremely detailed maps of the Milky Way, its structure, and history.
Energy Technology Data Exchange (ETDEWEB)
Zhilei, She; Hongge, Xu; Tingting, Zeng; Dikai, Li [China University of Geosciences, Physical Department, School of Mathematics and Physics, Wuhan (China); Gang, Chen [China University of Geosciences, Physical Department, School of Mathematics and Physics, Wuhan (China); Central China Normal University, Key Laboratory of Quark and Lepton Physics (MOE), Wuhan (China)
2016-04-15
The centrality dependence of light (anti)nuclei and (anti)hypertriton production in Pb-Pb collisions at √(s{sub NN}) = 2.76 TeV are investigated using the dynamically constrained phase-space coalescence (DCPC) model and the parton and hadron cascade (PACIAE) model. We found that the yields of light (anti)nuclei and (anti)hypertriton strongly depend on the centrality, i.e., their yields decrease rapidly with the increase of centrality; but their yield ratios are independent of centrality. The results from our theoretical model are well consistent with ALICE data. Furthermore, we found that the integrated yields of (anti)nuclei per participant nucleon increase from peripheral to central collisions, and a higher mass number corresponds to a more rapid increase of such yields. The coalescence parameters B{sub A} of light (anti)nuclei and (anti)hypernuclei are also analyzed. (orig.)
Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Attri, A.; Averichev, G. S.; Bai, X.; Bairathi, V.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Bouchet, J.; Brandenburg, J. D.; Brandin, A. V.; Bunzarov, I.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Campbell, J. M.; Cebra, D.; Chakaberia, I.; Chaloupka, P.; Chang, Z.; Chatterjee, A.; Chattopadhyay, S.; Chen, J. H.; Chen, X.; Cheng, J.; Cherney, M.; Christie, W.; Contin, G.; Crawford, H. J.; Das, S.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; di Ruzza, B.; Didenko, L.; Dilks, C.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, C. M.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Engelage, J.; Eppley, G.; Esha, R.; Evdokimov, O.; Eyser, O.; Fatemi, R.; Fazio, S.; Federic, P.; Fedorisin, J.; Feng, Z.; Filip, P.; Fisyak, Y.; Flores, C. E.; Fulek, L.; Gagliardi, C. A.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Greiner, L.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, S.; Gupta, A.; Guryn, W.; Hamad, A. I.; Hamed, A.; Haque, R.; Harris, J. W.; He, L.; Heppelmann, S.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Horvat, S.; Huang, T.; Huang, X.; Huang, B.; Huang, H. Z.; Huck, P.; Humanic, T. J.; Igo, G.; Jacobs, W. W.; Jang, H.; Jentsch, A.; Jia, J.; Jiang, K.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Khan, Z. H.; Kikoła, D. P.; Kisel, I.; Kisiel, A.; Kochenda, L.; Koetke, D. D.; Kosarzewski, L. K.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kumar, L.; Lamont, M. A. C.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Li, X.; Li, C.; Li, X.; Li, Y.; Li, W.; Lin, T.; Lisa, M. A.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, X.; Ma, R.; Ma, G. L.; Ma, Y. G.; Ma, L.; Magdy, N.; Majka, R.; Manion, A.; Margetis, S.; Markert, C.; Matis, H. S.; McDonald, D.; McKinzie, S.; Meehan, K.; Mei, J. C.; Minaev, N. G.; Mioduszewski, S.; Mishra, D.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nandi, B. K.; Nasim, Md.; Nayak, T. K.; Nigmatkulov, G.; Niida, T.; Nogach, L. V.; Noh, S. Y.; Novak, J.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Okorokov, V. A.; Olvitt, D.; Page, B. S.; Pak, R.; Pan, Y. X.; Pandit, Y.; Panebratsev, Y.; Pawlik, B.; Pei, H.; Perkins, C.; Pile, P.; Pluta, J.; Poniatowska, K.; Porter, J.; Posik, M.; Poskanzer, A. M.; Pruthi, N. K.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Sakrejda, I.; Salur, S.; Sandweiss, J.; Sarkar, A.; Schambach, J.; Scharenberg, R. P.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Seger, J.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, M. K.; Sharma, B.; Shen, W. Q.; Shi, Z.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Sikora, R.; Simko, M.; Singha, S.; Skoby, M. J.; Smirnov, N.; Smirnov, D.; Solyst, W.; Song, L.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Stepanov, M.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Sumbera, M.; Summa, B.; Sun, X. M.; Sun, Z.; Sun, Y.; Surrow, B.; Svirida, D. N.; Tang, Z.; Tang, A. H.; Tarnowsky, T.; Tawfik, A.; Thäder, J.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Todoroki, T.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Tripathy, S. K.; Tsai, O. D.; Ullrich, T.; Underwood, D. G.; Upsal, I.; Van Buren, G.; van Nieuwenhuizen, G.; Vandenbroucke, M.; Varma, R.; Vasiliev, A. N.; Vertesi, R.; Videbæk, F.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wang, Y.; Wang, G.; Wang, J. S.; Wang, H.; Wang, Y.; Wang, F.; Webb, G.; Webb, J. C.; Wen, L.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y.; Xiao, Z. G.; Xie, W.; Xie, G.; Xin, K.; Xu, H.; Xu, Z.; Xu, J.; Xu, Y. F.; Xu, Q. H.; Xu, N.; Yang, Y.; Yang, S.; Yang, C.; Yang, Y.; Yang, Y.; Yang, Q.; Ye, Z.; Ye, Z.; Yepes, P.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zbroszczyk, H.; Zha, W.; Zhang, J.; Zhang, Y.; Zhang, X. P.; Zhang, Z.; Zhang, J. B.; Zhang, S.; Zhang, S.; Zhang, J.; Zhao, J.; Zhong, C.; Zhou, L.; Zhu, X.; Zoulkarneeva, Y.; Zyzak, M.; STAR Collaboration
2016-09-01
We present measurements of second-order azimuthal anisotropy (v2) at midrapidity (|y |<1.0 ) for light nuclei d ,t ,3He (for √{sN N}=200 , 62.4, 39, 27, 19.6, 11.5, and 7.7 GeV) and antinuclei d ¯ (√{sN N}=200 , 62.4, 39, 27, and 19.6 GeV) and ¯3He (√{sN N}=200 GeV) in the STAR (Solenoidal Tracker at RHIC) experiment. The v2 for these light nuclei produced in heavy-ion collisions is compared with those for p and p ¯. We observe mass ordering in nuclei v2(pT) at low transverse momenta (pT<2.0 GeV/c ). We also find a centrality dependence of v2 for d and d ¯. The magnitude of v2 for t and 3He agree within statistical errors. Light-nuclei v2 are compared with predictions from a blast-wave model. Atomic mass number (A ) scaling of light-nuclei v2(pT) seems to hold for pT/A <1.5 GeV /c . Results on light-nuclei v2 from a transport-plus-coalescence model are consistent with the experimental measurements.
Stork, David G.; Nagy, Gabor
2010-02-01
We explored the working methods of the Italian Baroque master Caravaggio through computer graphics reconstruction of his studio, with special focus on his use of lighting and illumination in The calling of St. Matthew. Although he surely took artistic liberties while constructing this and other works and did not strive to provide a "photographic" rendering of the tableau before him, there are nevertheless numerous visual clues to the likely studio conditions and working methods within the painting: the falloff of brightness along the rear wall, the relative brightness of the faces of figures, and the variation in sharpness of cast shadows (i.e., umbrae and penumbrae). We explored two studio lighting hypotheses: that the primary illumination was local (and hence artificial) and that it was distant solar. We find that the visual evidence can be consistent with local (artificial) illumination if Caravaggio painted his figures separately, adjusting the brightness on each to compensate for the falloff in illumination. Alternatively, the evidence is consistent with solar illumination only if the rear wall had particular reflectance properties, as described by a bi-directional reflectance distribution function, BRDF. (Ours is the first research applying computer graphics to the understanding of artists' praxis that models subtle reflectance properties of surfaces through BRDFs, a technique that may find use in studies of other artists.) A somewhat puzzling visual feature-unnoted in the scholarly literature-is the upward-slanting cast shadow in the upper-right corner of the painting. We found this shadow is naturally consistent with a local illuminant passing through a small window perpendicular to the viewer's line of sight, but could also be consistent with solar illumination if the shadow was due to a slanted, overhanging section of a roof outside the artist's studio. Our results place likely conditions upon any hypotheses concerning Caravaggio's working methods and
Wu, Yonghua; Wang, Haifeng; Hadly, Elizabeth A.
2017-01-01
Nocturnality is a key evolutionary innovation of mammals that enables mammals to occupy relatively empty nocturnal niches. Invasion of ancestral mammals into nocturnality has long been inferred from the phylogenetic relationships of crown Mammalia, which is primarily nocturnal, and crown Reptilia, which is primarily diurnal, although molecular evidence for this is lacking. Here we used phylogenetic analyses of the vision genes involved in the phototransduction pathway to predict the diel activity patterns of ancestral mammals and reptiles. Our results demonstrated that the common ancestor of the extant Mammalia was dominated by positive selection for dim-light vision, supporting the predominate nocturnality of the ancestral mammals. Further analyses showed that the nocturnality of the ancestral mammals was probably derived from the predominate diurnality of the ancestral amniotes, which featured strong positive selection for bright-light vision. Like the ancestral amniotes, the common ancestor of the extant reptiles and various taxa in Squamata, one of the main competitors of the temporal niches of the ancestral mammals, were found to be predominate diurnality as well. Despite this relatively apparent temporal niche partitioning between ancestral mammals and the relevant reptiles, our results suggested partial overlap of their temporal niches during crepuscular periods. PMID:28425474
Ordering of the $0d_{5/2}$ and $1s_{1/2}$ proton levels in light nuclei
Hoffman, C R; Schiffer, J P
2016-01-01
A survey of the available single-proton data in $A\\leq17$ nuclei, along with calculations using a Woods-Saxon potential, show that the ordering of the $0d_{5/2}$ and $1s_{1/2}$ proton orbitals are determined primarily by the proximity of the $s$-state proton energy to the Coulomb barrier. This is analogous to the dependence of the corresponding neutron orbitals in proximity to the neutron threshold, that was previously discussed.
A relativistic mean-ﬁeld study of magic numbers in light nuclei from neutron to proton drip-lines
Indian Academy of Sciences (India)
T K Jha; M S Mehta; S K Patra; B K Raj; Raj K Gupta
2003-09-01
In an axially deformed relativistic mean-ﬁeld calculation of single-particle energy spectra of = 8 (Li–Mg) and = 14, 16 (C–Mg) isotonic chain and the one- and two-neutron separation energies of various isotopes of Li–Mg, new magic numbers are found to exist at = 6 and = 16 and/or = 14, which are in addition to the = 8 and = 20 magic numbers. In neutron-rich nuclei, the shell gap at = 6 is larger than at = 8 and a large gap is observed for = 16 or 14 for the neutron-rich and = 14 for proton-rich nuclei. Large shell gaps are also found to exist at = 14 and 16 or = 16 alone for nuclei near the -stability line. The above results are independent of the parameter sets TM2, NL3 and NL–SH used here. Similarly, new large shell gaps are predicted at = 6, 16 and/or 14 for protons.
Energy Technology Data Exchange (ETDEWEB)
Morelli, L., E-mail: luca.morelli@bo.infn.it; D’Agostino, M.; Bruno, M. [Dipartimento di Fisica e Astronomia dell’Università and INFN, Bologna (Italy); Baiocco, G. [Dipartimento di Fisica dell’Università and INFN, Pavia (Italy); Gulminelli, F. [CNRS, LPC, Caen, France and ENSICAEN, Caen (France); Cinausero, M.; Gramegna, F.; Marchi, T. [INFN, Laboratori Nazionali di Legnaro, Legnaro (Padova) (Italy); Degerlier, M. [University of Nevsehir, Physics Department, Nevsehir (Turkey); Fabris, D. [INFN, Sezione di Padova, Padova (Italy); Barlini, S.; Bini, M.; Casini, G.; Gelli, N.; Olmi, A.; Pasquali, G.; Piantelli, S. [Dipartimento di Fisica e Astronomia dell’Università and INFN, Firenze (Italy)
2015-10-15
In the recent years, cluster structures have been evidenced in many ground and excited states of light nuclei [1, 2]. Within the currently ongoing experimental campaign by the NUCL-EX collaboration we have measured the {sup 12}C+{sup 12}C and {sup 14}N+{sup 10}B reactions at 95 MeV and 80 MeV respectively, and compared experimental data corresponding to complete fusion of target and projectile into an excited {sup 24}Mg nucleus to the results of a pure statistical model[3, 4]. We found clear deviations from the statstical model in the decay pattern: emission channels involving multiple α particles are more probable than expected from a purely statistical behavior. To continue the investigation on light systems, we have recentely measured the {sup 16}O+{sup 12}C reaction at three different beam energies, namely E{sub beam} = 90, 110 and 130 MeV.
Sáro, S
2003-01-01
Experiments leading to transuranium and far transuranium nuclei as far as element 106 (seaborgium) are described. Physical knowledge derived from experimental data at this stage of complete synthesis nuclear reactions since the 1980s is analyzed. The effect of the shell structure on the stability of the nuclei, the extra-push effect, and the effect of isospin are discussed. Experiments leading to the synthesis of nuclei with Z = 107 - 112 by cold fusion are also described, as are hot fusion reactions resulting in superheavy nuclei Z = 114, 116 where, however, confirmation is only pending. Current state of the art in this area is also highlighted
The 1.6 micron near infrared nuclei of 3C radio galaxies: Jets, thermal emission or scattered light?
Baldi, R D; Capetti, A; Sparks, W; Macchetto, F D; O'Dea, C P; Axon, D J; Baum, S A; Quillen, A C
2010-01-01
Using HST NICMOS 2 observations we have measured 1.6-micron near infrared nuclear luminosities of 100 3CR radio galaxies with z<0.3, by modeling and subtracting the extended emission from the host galaxy. We performed a multi-wavelength statistical analysis (including optical and radio data) of the properties of the nuclei following classification of the objects into FRI and FRII, and LIG (low-ionization galaxies), HIG (high-ionization galaxies) and BLO (broad-lined objects) using the radio morphology and optical spectra, respectively. The correlations among near infrared, optical, and radio nuclear luminosity support the idea that the near infrared nuclear emission of FRIs has a non-thermal origin. Despite the difference in radio morphology, the multi-wavelength properties of FRII LIG nuclei are statistically indistinguishable from those of FRIs, an indication of a common structure of the central engine. All BLOs show an unresolved near infrared nucleus and a large near infrared excess with respect to FRI...
Effects of the spin-orbit and tensor interactions on the M1 and E2 excitations in light nuclei
Fayache, M S; Zamick, L; Von Neumann-Cosel, P; Richter, A
1996-01-01
The effects of varying the spin-orbit and tensor components of a realistic interaction on M1 excitation rates and B(E2)'s are studied on nuclei in the 0p and 1s-0d shells. Not only the total M1 but also the spin and orbital parts separately are studied. The single-particle energies are first calculated with the same interaction that is used between the valence nucleons. Later this stringent condition is relaxed somewhat and the 1s level is raised relative to 0d. For nuclei up to ^{28}Si, much better results i.e stronger B(M1) rates are obtained by increasing the strength of the spin-orbit interaction relative to the free value. This is probably also true for ^{32}S, but ^{36}Ar presents some difficulties. The effects of weakening the tensor interaction are also studied. On a more subtle level, the optimum spin-orbit interaction in the lower half of the s-d shell, as far as M1 excitations are concerned, is substantially larger than the difference E(J=3/2^+)_1-E(J=5/2^+)_1=5.2~MeV in ^{17}O. A larger spin-orbit...
Erlykin, A. D.; Wolfendale, A. W.
2016-10-01
Evidence for a local ‘single source’ of cosmic rays is amassing by way of the recent precise measurements of various cosmic ray energy spectra from the AMS-02 instrument. To observations of individual cosmic ray nuclei, electrons, positrons and antiprotons must now be added the determination of the boron-to-carbon ratio and the energy spectrum of lithium to 2000 GV with high precision. Our analysis leads us to claim that, with certain assumptions about propagation in the Galaxy, the results confirm our arguments regarding the presence of a local single source, perhaps, a supernova remnant (SNR). An attempt is made to determine some of the properties of this SNR and its progenitor star.
Pantic, Igor; Pantic, Senka; Basta-Jovanovic, Gordana
2012-06-01
In our study we investigated the relationship between conventional morphometric indicators of nuclear size and shape (area and circularity) and the parameters of gray level co-occurrence matrix texture analysis (entropy, homogeneity, and angular second moment) in cells committed to apoptosis. A total of 432 lymphocyte nuclei images from the spleen germinal center light zones (cells in early stages of apoptosis) were obtained from eight healthy male guinea pigs previously immunized with sheep red blood cells (antigen). For each nucleus, area, circularity, entropy, homogeneity, and angular second moment were determined. All measured parameters of gray level co-occurrence matrix (GLCM) were significantly correlated with morphometric indicators of nuclear size and shape. The strongest correlation was observed between GLCM homogeneity and nuclear area (p GLCM method may be a powerful tool in evaluation of ultrastructural nuclear changes during early stages of the apoptotic process.
Energy Technology Data Exchange (ETDEWEB)
Sundaralingam, N.
1993-06-08
We study multiple muon events (muon bundles) recorded underground at a depth of 2090 mwe. To penetrate to this depth, the muons must have energies above 0.8 TeV at the Earth`s surface; the primary cosmic ray nuclei which give rise to the observed muon bundles have energies at incidence upon the upper atmosphere of 10 to 10{sup 5}TeV. The events are detected using the Soudan 2 experiment`s fine grained tracking calorimeter which is surrounded by a 14 m {times}10 m {times} 31 m proportional tube array (the ``active shield``). Muon bundles which have at least one muon traversing the calorimeter, are reconstructed using tracks in the calorimeter together with hit patterns in the proportional tube shield. All ionization pulses are required to be coincident within 3 microseconds. A goal of this study is to investigate the relative nuclear abundances in the primary cosmic radiation around the ``knee`` region (10{sup 3} {minus} 10{sup 4} TeV) of the incident energy spectrum. Four models for the nuclear composition of cosmic rays are considered: The Linsley model, the Constant Mass Composition model (CMC), the Maryland model and the Proton-poor model. A Monte Carlo which incorporates one model at a time is used to simulate events which are then reconstructed using the same computer algorithms that are used for the data. Identical cuts and selections are applied to the data and to the simulated events.
Ciemała, M.; Kmiecik, M.; Maj, A.; Mazurek, K.; Bracco, A.; Kravchuk, V. L.; Casini, G.; Barlini, S.; Baiocco, G.; Bardelli, L.; Bednarczyk, P.; Benzoni, G.; Bini, M.; Blasi, N.; Brambilla, S.; Bruno, M.; Camera, F.; Carboni, S.; Cinausero, M.; Chbihi, A.; Chiari, M.; Corsi, A.; Crespi, F. C. L.; D'Agostino, M.; Degerlier, M.; Fornal, B.; Giaz, A.; Gramegna, F.; Krzysiek, M.; Leoni, S.; Marchi, T.; Matejska-Minda, M.; Mazumdar, I.; Meczyński, W.; Million, B.; Montanari, D.; Morelli, L.; Myalski, S.; Nannini, A.; Nicolini, R.; Pasquali, G.; Piantelli, S.; Prete, G.; Roberts, O. J.; Schmitt, Ch.; Styczeń, J.; Szpak, B.; Valdré, S.; Wasilewska, B.; Wieland, O.; Wieleczko, J. P.; Ziebliński, M.; Dudek, J.; Dinh Dang, N.
2015-05-01
High-energy giant dipole resonance (GDR) γ rays were measured following the decay of the hot, rotating compound nucleus of 88Mo, produced at excitation energies of 124 and 261 MeV. The reaction 48Ti + 40Ca at 300 and 600 MeV bombarding energies has been used. The data were analyzed using the statistical model Monte Carlo code gemini++. It allowed extracting the giant dipole resonance parameters by fitting the high-energy γ -ray spectra. The extracted GDR widths were compared with the available data at lower excitation energy and with theoretical predictions based on (i) The Lublin-Strasbourg drop macroscopic model, supplemented with thermal shape fluctuations analysis, and (ii) The phonon damping model. The theoretical predictions were convoluted with the population matrices of evaporated nuclei from the statistical model gemini++. Also a comparison with the results of a phenomenological expression based on the existing systematics, mainly for lower temperature data, is presented and discussed. A possible onset of a saturation of the GDR width was observed around T =3 MeV.
Bertsch, G F
2016-01-01
Gerry Brown initiated some early studies on the coexistence of different nuclear shapes. The subject has continued to be of interest and is crucial for understanding nuclear fission. We now have a very good picture of the potential energy surface with respect to shape degrees of freedom in heavy nuclei, but the dynamics remain problematic. In contrast, the early studies on light nuclei were quite successful in describing the mixing between shapes. Perhaps a new approach in the spirit of the old calculations could better elucidate the character of the fission dynamics and explain phenomena that current theory does not model well.
Holt, Roy J.
2016-03-01
Electron scattering at very high Bjorken x from hadrons provides an excellent test of models, has an important role in high energy physics, and from nuclei, provides a window into short range correlations. Light nuclei have a key role because of the relatively well-known nuclear structure. The development of a novel tritium target for Jefferson Lab has led to renewed interest in the mass three system. For example, deep inelastic scattering experiments in the light nuclei provide a powerful means to determine the neutron structure function. The isospin dependence of electron scattering from mass-3 nuclei provide information on short range correlations in nuclei. The program using the new tritium target will be presented along with a summary of other experiments aimed at revealing the large-x structure of the nucleon.
Directory of Open Access Journals (Sweden)
Holt Roy J.
2016-01-01
Full Text Available Electron scattering at very high Bjorken x from hadrons provides an excellent test of models, has an important role in high energy physics, and from nuclei, provides a window into short range correlations. Light nuclei have a key role because of the relatively well-known nuclear structure. The development of a novel tritium target for Jefferson Lab has led to renewed interest in the mass three system. For example, deep inelastic scattering experiments in the light nuclei provide a powerful means to determine the neutron structure function. The isospin dependence of electron scattering from mass-3 nuclei provide information on short range correlations in nuclei. The program using the new tritium target will be presented along with a summary of other experiments aimed at revealing the large-x structure of the nucleon.
Marinova, K P
2002-01-01
Nuclear Moments and radii of light unstable isotopes are investigated by applying different high-sensitivity and high-resolution techniques based on collinear fast-beam laser spectroscopy. A study of nuclear structure in the sd shell is performed on neon isotopes in the extended chain of $^{17-28}$Ne, in particular on the proton-halo candidate $^{17}$Ne. Measurements of hyperfine structure and isotope shift have become possible by introducing an ultra-sensitive non-optical detection method which is based on optical pumping, state-selective collisional ionization and $\\beta$-activity counting. The small effect of nuclear radii on the optical isotope shifts of light elements requires very accurate measurements. The errors are dominated by uncertainties of the Doppler shifts which are conventionally determined from precisely measured acceleration voltages. These uncertainties are removed by measuring the beam energy with simultaneous excitation of two optical lines in parallel / antiparallel beam configuration. ...
Orlin, V N
2002-01-01
A coupled-channels approach in intermediate coupling shell model for describing the non-compound component of nucleon-nucleus reactions is proposed. The goal of the model is to take into account the influence of collective doorway states (giant resonances) on the characteristics of nucleon-induced reactions on light and medium nuclei for incident energies epsilon <= 12 MeV
Directory of Open Access Journals (Sweden)
Y. Shinozuka
2015-01-01
Full Text Available We examine the relationship between the number concentration of boundary-layer cloud condensation nuclei (CCN and light extinction to investigate underlying aerosol processes and satellite-based CCN estimates. Regression applied to a variety of airborne and ground-based measurements identifies the CCN (cm−3 at 0.4 ± 0.1% supersaturation with 100.3α +1.3 σ0.75 where σ (M m−1 is the 500 nm extinction coefficient by dried particles and α is the Angstrom exponent. The deviation of one kilometer horizontal average data from this approximation is typically within a factor of 2.0. ∂ log CCN/∂ log σ is less than unity because, among other explanations, aerosol growth processes generally make particles scatter more light without increasing their number. This, barring extensive data aggregation and special meteorology-aerosol connections, associates doubling of aerosol optical depth with less than doubling of CCN, contrary to common assumptions in satellite-based analysis of aerosol-cloud interactions.
Morelli, L.; Bruno, M.; D'Agostino, M.; Baiocco, G.; Gulminelli, F.; Cinausero, M.; Degerlier, M.; Fabris, D.; Gramegna, F.; Marchi, T.; Barlini, S.; Bini, M.; Casini, G.; Gelli, N.; Pasquali, G.; Piantelli, S.; Valdrè, S.
2016-06-01
In the recent years, cluster structures have been evidenced in many ground and excited states of light nuclei [1, 2]. The decay of highly excited states of 24Mg is studied in fusion evaporation events completely detected in charge in the reactions 12C+12C and 14N+10B at 95 and 80 MeV incident energy, respectively, and compared to the results of a pure statistical model [3, 4]. Inclusive variables are in general well reproduced by the model. We found clear deviations from the statistical model if we select emission channels involving multiple α particles which are more probable than expected from a purely statistical behavior. Data from 12C+12C reaction have been analyzed in order to study the decay of the Hoyle state of 12C* with two different selections: peripheral binary collisions and 6α decay channel in central events. To continue the investigation on light systems, we have recently measured the 16O+12C reaction at three different beam energies, namely Ebeam = 90, 110 and 130 MeV. Preliminary results are presented.
Energy Technology Data Exchange (ETDEWEB)
Akram, W.; Schönbächler, M. [School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom); Sprung, P. [Institut für Planetologie, Universität Münster, Wilhelm-Klemm-Strasse 10, D-48149 Münster (Germany); Vogel, N. [Institute for Geochemistry and Petrology, ETH, Clausiusstrasse 25, 8092 Zürich (Switzerland)
2013-11-10
Recent work based on analyses of meteorite and terrestrial whole-rock samples showed that the r- and s- process isotopes of Hf were homogeneously distributed throughout the inner solar system. We report new Hf isotope data for Calcium-Aluminum-rich inclusions (CAIs) of the CV3 carbonaceous chondrite Allende, and novel high-precision Zr isotope data for these CAIs and three carbonaceous chondrites (CM, CO, CK). Our Zr data reveal enrichments in the neutron-rich isotope {sup 96}Zr (≤1ε in {sup 96}Zr/{sup 90}Zr) for bulk chondrites and CAIs (∼2ε). Potential isotope effects due to incomplete sample dissolution, galactic and cosmic ray spallation, and the nuclear field shift are assessed and excluded, leading to the conclusion that the {sup 96}Zr isotope variations are of nucleosynthetic origin. The {sup 96}Zr enrichments are coupled with {sup 50}Ti excesses suggesting that both nuclides were produced in the same astrophysical environment. The same CAIs also exhibit deficits in r-process Hf isotopes, which provides strong evidence for a decoupling between the nucleosynthetic processes that produce the light (A ≤ 130) and heavy (A > 130) neutron-rich isotopes. We propose that the light neutron-capture isotopes largely formed in Type II supernovae (SNeII) with higher mass progenitors than the supernovae that produced the heavy r-process isotopes. In the context of our model, the light isotopes (e.g. {sup 96}Zr) are predominantly synthesized via charged-particle reactions in a high entropy wind environment, in which Hf isotopes are not produced. Collectively, our data indicates that CAIs sampled an excess of materials produced in a normal mass (12-25 M{sub ☉}) SNII.
Kunieda, Satoshi
2017-09-01
We report the status of the R-matrix code AMUR toward consistent cross-section evaluation and covariance analysis for the light-mass nuclei. The applicable limit of the code is extended by including computational capability for the charged-particle elastic scattering cross-sections and the neutron capture cross-sections as example results are shown in the main texts. A simultaneous analysis is performed on the 17O compound system including the 16O(n,tot) and 13C(α,n)16O reactions together with the 16O(n,n) and 13C(α,α) scattering cross-sections. It is found that a large theoretical background is required for each reaction process to obtain a simultaneous fit with all the experimental cross-sections we analyzed. Also, the hard-sphere radii should be assumed to be different from the channel radii. Although these are technical approaches, we could learn roles and sources of the theoretical background in the standard R-matrix.
Drobyshevski, E M
2004-01-01
In 1997, we proposed a model of the ball lightning (BL) whose activity is accounted for by energy release in the fusion of light nuclei, most probably, carbon in organic fibers (Proc. ISBL 97, p.157). The fusion is provided by catalytic action of superheavy negative particles making up the Galactic Dark Matter. We called them DArk Electric Matter Objects, or daemons. The daemons are assumed to be elementary black holes (M ~ 10^-5 g) carrying a charge of up to Ze = 10e. Experiments have culminated in 2000 by the discovery of daemons. We used the two-screen scintillation technique with a scintillator ZnS(Ag). Measurements showed the daemon flux striking the Earth to be ~10^-9 cm^-2s^-1 for an object velocity of as low as ~<10-30 km/s. The half-year periodicity of the flux was revealed, which can be assigned to daemons being captured into helio- and geocentric orbits as the Solar system moves through the DM background (see astro-ph/0402367). The next step in creating a daemon-mediated BL to achieve controlled...
Reactions with light exotic nuclei
Energy Technology Data Exchange (ETDEWEB)
Lichtenthäler, R.; Faria, P.N. de; Pires, K.C.C.; Lepine-Szily, A.; Guimaraes, V.; Mendes Junior, D.R.; Assuncao, M.; Barioni, A.; Morcelle, V.; Morais, M.C.; Camargo Junior, O.; Alcantara Nuñez, J. [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Instituto de Fisica; Moro, A.M. [Departamento de FAMN, Universidad de Sevilla, Sevilla (Spain); Arazi, A. [Laboratorio Tandar, Departamento de Fisica, Comision Nacional de Energia Atomica (CNEA), Buenos Aires (Argentina); Rodriguez-Gallardo, M. [Instituto de Estructura de la Materia, CSIC, Madrid (Spain)
2014-07-01
Experimental cross sections for the {sup 6}He+{sup 120}Sn are analysed. Elastic scattering angular distributions and alpha particle production cross sections have been measured and are compared with the total reaction cross sections. (author)
Reactions with light exotic nuclei
Directory of Open Access Journals (Sweden)
Lichtenthäler R.
2014-04-01
Full Text Available Experimental cross sections for the 6He+120Sn are analysed. Elastic scattering angular distributions and alpha particle production cross sections have been measured and are compared with the total reaction cross sections.
Following the pioneering discovery of alpha clustering and of molecular resonances, the field of nuclear clustering is today one of those domains of heavy-ion nuclear physics that faces the greatest challenges, yet also contains the greatest opportunities. After many summer schools and workshops, in particular over the last decade, the community of nuclear molecular physicists has decided to collaborate in producing a comprehensive collection of lectures and tutorial reviews covering the field. This third volume follows the successful Lect. Notes Phys. 818 (Vol. 1) and 848 (Vol. 2), and comprises six extensive lectures covering the following topics: - Gamma Rays and Molecular Structure - Faddeev Equation Approach for Three Cluster Nuclear Reactions - Tomography of the Cluster Structure of Light Nuclei Via Relativistic Dissociation - Clustering Effects Within the Dinuclear Model : From Light to Hyper-heavy Molecules in Dynamical Mean-field Approach - Clusterization in Ternary Fission - Clusters in Light N...
King, Gary; Rosen, Ori; Tanner, Martin A.
2004-09-01
This collection of essays brings together a diverse group of scholars to survey the latest strategies for solving ecological inference problems in various fields. The last half-decade has witnessed an explosion of research in ecological inference--the process of trying to infer individual behavior from aggregate data. Although uncertainties and information lost in aggregation make ecological inference one of the most problematic types of research to rely on, these inferences are required in many academic fields, as well as by legislatures and the Courts in redistricting, by business in marketing research, and by governments in policy analysis.
Photoproduction of mesons off nuclei
Krusche, B
2011-01-01
Recent results for the photoproduction of mesons off nuclei are reviewed. These experiments have been performed for two major lines of research related to the properties of the strong interaction. The investigation of nucleon resonances requires light nuclei as targets for the extraction of the isospin composition of the electromagnetic excitations. This is done with quasi-free meson photoproduction off the bound neutron and supplemented with the measurement of coherent photoproduction reactions, serving as spin and/or isospin filters. Furthermore, photoproduction from light and heavy nuclei is a very efficient tool for the study of the interactions of mesons with nuclear matter and the in-medium properties of hadrons. Experiments are currently rapidly developing due to the combination of high quality tagged (and polarized) photon beams with state-of-the-art 4pi detectors and polarized targets.
Towards the exact calculation of medium nuclei
Energy Technology Data Exchange (ETDEWEB)
Gandolfi, Stefano [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Carlson, Joseph Allen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lonardoni, Diego [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wang, Xiaobao [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2016-12-19
The prediction of the structure of light and medium nuclei is crucial to test our knowledge of nuclear interactions. The calculation of the nuclei from two- and three-nucleon interactions obtained from rst principle is, however, one of the most challenging problems for many-body nuclear physics.
Ajay Kumar, M.; Srikanth, N.
2014-03-01
In HVDC Light transmission systems, converter control is one of the major fields of present day research works. In this paper, fuzzy logic controller is utilized for controlling both the converters of the space vector pulse width modulation (SVPWM) based HVDC Light transmission systems. Due to its complexity in the rule base formation, an intelligent controller known as adaptive neuro fuzzy inference system (ANFIS) controller is also introduced in this paper. The proposed ANFIS controller changes the PI gains automatically for different operating conditions. A hybrid learning method which combines and exploits the best features of both the back propagation algorithm and least square estimation method is used to train the 5-layer ANFIS controller. The performance of the proposed ANFIS controller is compared and validated with the fuzzy logic controller and also with the fixed gain conventional PI controller. The simulations are carried out in the MATLAB/SIMULINK environment. The results reveal that the proposed ANFIS controller is reducing power fluctuations at both the converters. It also improves the dynamic performance of the test power system effectively when tested for various ac fault conditions.
Energy Technology Data Exchange (ETDEWEB)
Bednarczyk, P. [Institut de Recherches Subatomiques, Strasbourg (France); H. Niewodniczanski Institute of Nuclear Physics, Krakow (Poland); Styczen, J.; Grebosz, J.; Lach, M.; Maj, A.; Meczynski, W.; Zieblinski, M. [H. Niewodniczanski Institute of Nuclear Physics, Krakow (Poland); Bracco, A. [Universita degli Studi di Milano and INFN, Milano (Italy); Curien, D.; Merdinger, J.C.; Nowacki, F.; Vivien, J.P. [Institut de Recherches Subatomiques, Strasbourg (France); Smith, M.B.; Spohr, K. [University of Paisley, Paisley, Scotland (United Kingdom)
2004-04-01
Intruder rotational bands in {sup 45}Sc and {sup 45}Ti have been investigated up to the maximum aligned angular momentum by means of EUROBALL IV and the Recoil Filter Detector (RFD). The use of the RFD allowed for a reduction of the {gamma}-line Doppler broadening and, moreover, for a determination of very short level lifetimes. In the studied nuclei, the estimated deformation shows a gradual disappearance of the collectivity at the highest available spins. (orig.)
Directory of Open Access Journals (Sweden)
Richard Shoemaker
2014-04-01
Full Text Available Establishing causality has been a problem throughout history of philosophy of science. This paper discusses the philosophy of causal inference along the different school of thoughts and methods: Rationalism, Empiricism, Inductive method, Hypothetical deductive method with pros and cons. The article it starting from the Problem of Hume, also close to the positions of Russell, Carnap, Popper and Kuhn to better understand the modern interpretation and implications of causal inference in epidemiological research.
Federal Laboratory Consortium — Lighting Systems Test Facilities aid research that improves the energy efficiency of lighting systems. • Gonio-Photometer: Measures illuminance from each portion of...
DEFF Research Database (Denmark)
Prescott, N.B.; Kristensen, Helle Halkjær; Wathes, C.M.
2004-01-01
This chapter presents the effect of artificial light environments (light levels, colour, photoperiod and flicker) on the welfare of broilers in terms of vision, behaviour, lameness and mortality......This chapter presents the effect of artificial light environments (light levels, colour, photoperiod and flicker) on the welfare of broilers in terms of vision, behaviour, lameness and mortality...
Local chiral potentials with ${\Delta}$ -intermediate states and the structure of light nuclei
Energy Technology Data Exchange (ETDEWEB)
Piarulli, M.; Girlanda, L.; Schiavilla, R.; Kievsky, A.; Lovato, A.; Marcucci, L. E.; Pieper, Steven C.; Viviani, M.; Wiringa, R. B.
2016-11-01
We present fully local versions of the minimally non-local nucleon-nucleon potentials constructed in a previous paper [M.\\ Piarulli {\\it et al.}, Phys.\\ Rev.\\ C {\\bf 91}, 024003 (2015)], and use them in hypersperical-harmonics and quantum Monte Carlo calculations of ground and excited states of $^3$H/$^3$He, $^4$He, and $^6$He/$^6$Li nuclei. The long-range part of these local potentials includes one- and two-pion exchange contributions without and with $\\Delta$-isobars in the intermediate states up to order $Q^3$ ($Q$ denotes generically the low momentum scale) in the chiral expansion, while the short-range part consists of contact interactions up to order $Q^4$. The low-energy constants multiplying these contact interactions are fitted to the 2013 Granada database in two different ranges of laboratory energies, either 0--125 MeV or 0--200 MeV, and to the deuteron binding energy and $nn$ singlet scattering length. Fits to these data are performed for three models characterized by long- and short-range cutoffs, $R_{\\rm L}$ and $R_{\\rm S}$ respectively, ranging from $(R_{\\rm L},R_{\\rm S})=(1.2,0.8)$ fm down to $(0.8,0.6)$ fm. The long-range (short-range) cutoff regularizes the one- and two-pion exchange (contact) part of the potential.
Evolution of active galactic nuclei
Merloni, Andrea
2012-01-01
[Abriged] Supermassive black holes (SMBH) lurk in the nuclei of most massive galaxies, perhaps in all of them. The tight observed scaling relations between SMBH masses and structural properties of their host spheroids likely indicate that the processes fostering the growth of both components are physically linked, despite the many orders of magnitude difference in their physical size. This chapter discusses how we constrain the evolution of SMBH, probed by their actively growing phases, when they shine as active galactic nuclei (AGN) with luminosities often in excess of that of the entire stellar population of their host galaxies. Following loosely the chronological developments of the field, we begin by discussing early evolutionary studies, when AGN represented beacons of light probing the most distant reaches of the universe and were used as tracers of the large scale structure. This early study turned into AGN "Demography", once it was realized that the strong evolution (in luminosity, number density) of ...
Energy Technology Data Exchange (ETDEWEB)
Atchison, F.
1998-09-01
The PSIMECX library contains calculated nuclide production cross-sections from neutron-induced reactions in the energy range about 2 to 800 MeV in the following 72 stable isotopes of 24 elements: {sup 12}C, {sup 13}C, {sup 16}O, {sup 17}O, {sup 18}O, {sup 23}Na, {sup 24}Mg, {sup 25}Mg, {sup 26}Mg, {sup 27}Al, {sup 28}Si, {sup 29}Si, {sup 30}Si, {sup 31}P, {sup 32}S, {sup 33}S, {sup 34}S, {sup 36}S, {sup 35}Cl, {sup 37}Cl, {sup 39}K, {sup 40}K, {sup 41}K, {sup 40}Ca, {sup 42}Ca, {sup 43}Ca, {sup 44}Ca, {sup 46}Ca, {sup 48}Ca, {sup 46}Ti, {sup 47}Ti, {sup 48}Ti, {sup 49}Ti, {sup 50}Ti, {sup 50}V, {sup 51}V, {sup 50}Cr, {sup 52}Cr, {sup 53}Cr, {sup 54}Cr, {sup 55}Mn, {sup 54}Fe, {sup 56}Fe, {sup 57}Fe, {sup 58}Fe, {sup 58}Ni, {sup 60}Ni, {sup 61}Ni, {sup 62}Ni, {sup 64}Ni, {sup 63}Cu, {sup 65}Cu, {sup 64}Zn, {sup 66}Zn, {sup 67}Zn, {sup 68}Zn, {sup 70}Zn, {sup 92}Mo, {sup 94}Mo, {sup 95}Mo, {sup 96}Mo, {sup 97}Mo, {sup 98}Mo, {sup 100}Mo, {sup 121}Sb, {sup 123}Sb, {sup 204}Pb, {sup 206}Pb, {sup 207}Pb, {sup 208}Pb, {sup 232}Th and {sup 238}U. The energy range covers essentially all transmutation channels other than capture. The majority of the selected elements are principal constituents of normal materials of construction used in and around accelerator facilities and the library is, first and foremost, designed to be a tool for the estimation of their activation in wide-band neutron fields. This second report, of a series of three, describes and discusses the calculational methods used for the stable isotopes up to and including {sup 123}Sb. The library itself has been described in the first report of the series and the treatment for the heavy nuclei is given in the third. (author)
Electric monopole transitions from low energy excitations in nuclei
Wood, J L; De Coster, C; Heyde, Kris L G
1999-01-01
Electric monopole (E0) properties are studied across the entire nuclear mass surface. Besides an introductory discussion of various model results (shell model, geometric vibrational and rotational models, algebraic models), we point out that many of the largest E0 transition strengths, $\\rho^2$(E0), are associated with shape mixing. We discuss in detail the manifestation of E0 transitions and present extensive data for~: single-closed shell nuclei, vibrational nuclei, well-deformed nuclei, nuclei that exhibit sudden ground-state changes, and nuclei that exhibit shape coexistence and intruder states. We also give attention to light nuclei, odd-A nuclei, and illustrate a suggested relation between $\\rho^2$(E0) and isotopic shifts.
Thielmann, H W; Popanda, O
1998-02-01
DNA topoisomerase II was monitored with the monoclonal antibody Ki-S1 in human fibroblasts after irradiation of cells with 254-nm UV light and -rays from a 137Cs source. DNA topoisomerase II was localized immunohistochemically as bright fluorescent dots in the karyoplasm. Investigated fibroblasts originated from normal human donors and a xeroderma pigmentosum patient (XP12BE). All cell lines showed a time and dose-dependent increase in DNA topoisomerase II abundance after irradiation. The increase may reflect enhanced accessibility of the enzyme, enhanced gene expression or enhanced stabilization of mRNA or protein molecules. The effect was detectable as early as 1 h after irradiation at doses 3 J/m2 or 3 Gy. It passed through a maximum and decreased within 18 h (UV light) or 6 h ( -rays). Except for the duration of the response, no principal differences were seen between the effects caused by UV light and those elicited by -rays. The increase in enzyme levels might be part of the well-known DNA damage responses which operate in cell-protective or DNA-reparative pathways or may reflect initiation of apoptosis. DNA topoisomerase I was detected with a commercially available polyclonal antibody raised against human DNA topoisomerase I. In unirradiated cells, DNA topoisomerase I was found to be mainly concentrated in nucleoli. Irradiation with -rays changed the staining pattern in that it caused a multitude of DNA topoisomerase I-rich centers to occur which may reflect sites of transcription of radiation-inducible genes.
Directory of Open Access Journals (Sweden)
Noriyuki Suetsugu
Full Text Available Light-induced chloroplast movement and attachment to the plasma membrane are dependent on actin filaments. In Arabidopsis thaliana, the short actin filaments on the chloroplast envelope, cp-actin filaments, are essential for chloroplast movement and positioning. Furthermore, cp-actin-filament-mediated chloroplast movement is necessary for the strong-light-induced nuclear avoidance response. The proteins CHLOROPLAST UNUSUAL POSITIONING 1 (CHUP1, KINESIN-LIKE PROTEIN FOR ACTIN-BASED CHLOROPLAST MOVEMENT 1 (KAC1 and KAC2 are required for the generation and/or maintenance of cp-actin filaments in Arabidopsis. In land plants, CHUP1 and KAC family proteins play pivotal roles in the proper movement of chloroplasts and their attachment to the plasma membrane. Here, we report similar but distinct phenotypes in chloroplast and nuclear photorelocation movements between chup1 and kac1kac2 mutants. Measurement of chloroplast photorelocation movement indicated that kac1kac2, but not chup1, exhibited a clear strong-light-induced increase in leaf transmittance changes. The chloroplast movement in kac1kac2 depended on phototropin 2, CHUP1 and two other regulators for cp-actin filaments, PLASTID MOVEMENT IMPAIRED 1 and THRUMIN 1. Furthermore, kac1kac2 retained a weak but significant nuclear avoidance response although chup1 displayed a severe defect in the nuclear avoidance response. The kac1kac2chup1 triple mutant was completely defective in both chloroplast and nuclear avoidance responses. These results indicate that CHUP1 and the KACs function somewhat independently, but interdependently mediate both chloroplast and nuclear photorelocation movements.
Suetsugu, Noriyuki; Higa, Takeshi; Gotoh, Eiji; Wada, Masamitsu
2016-01-01
Light-induced chloroplast movement and attachment to the plasma membrane are dependent on actin filaments. In Arabidopsis thaliana, the short actin filaments on the chloroplast envelope, cp-actin filaments, are essential for chloroplast movement and positioning. Furthermore, cp-actin-filament-mediated chloroplast movement is necessary for the strong-light-induced nuclear avoidance response. The proteins CHLOROPLAST UNUSUAL POSITIONING 1 (CHUP1), KINESIN-LIKE PROTEIN FOR ACTIN-BASED CHLOROPLAST MOVEMENT 1 (KAC1) and KAC2 are required for the generation and/or maintenance of cp-actin filaments in Arabidopsis. In land plants, CHUP1 and KAC family proteins play pivotal roles in the proper movement of chloroplasts and their attachment to the plasma membrane. Here, we report similar but distinct phenotypes in chloroplast and nuclear photorelocation movements between chup1 and kac1kac2 mutants. Measurement of chloroplast photorelocation movement indicated that kac1kac2, but not chup1, exhibited a clear strong-light-induced increase in leaf transmittance changes. The chloroplast movement in kac1kac2 depended on phototropin 2, CHUP1 and two other regulators for cp-actin filaments, PLASTID MOVEMENT IMPAIRED 1 and THRUMIN 1. Furthermore, kac1kac2 retained a weak but significant nuclear avoidance response although chup1 displayed a severe defect in the nuclear avoidance response. The kac1kac2chup1 triple mutant was completely defective in both chloroplast and nuclear avoidance responses. These results indicate that CHUP1 and the KACs function somewhat independently, but interdependently mediate both chloroplast and nuclear photorelocation movements.
Directory of Open Access Journals (Sweden)
Morelli L.
2016-01-01
Inclusive variables are in general well reproduced by the model. We found clear deviations from the statistical model if we select emission channels involving multiple α particles which are more probable than expected from a purely statistical behavior. Data from 12C+12C reaction have been analyzed in order to study the decay of the Hoyle state of 12C* with two different selections: peripheral binary collisions and 6α decay channel in central events. To continue the investigation on light systems, we have recently measured the 16O+12C reaction at three different beam energies, namely Ebeam = 90, 110 and 130 MeV. Preliminary results are presented.
Rohatgi, Vijay K
2003-01-01
Unified treatment of probability and statistics examines and analyzes the relationship between the two fields, exploring inferential issues. Numerous problems, examples, and diagrams--some with solutions--plus clear-cut, highlighted summaries of results. Advanced undergraduate to graduate level. Contents: 1. Introduction. 2. Probability Model. 3. Probability Distributions. 4. Introduction to Statistical Inference. 5. More on Mathematical Expectation. 6. Some Discrete Models. 7. Some Continuous Models. 8. Functions of Random Variables and Random Vectors. 9. Large-Sample Theory. 10. General Meth
Robertson, William C
2003-01-01
Why is left right and right left in the mirror? Baffled by the basics of reflection and refraction? Wondering just how the eye works? If you have trouble teaching concepts about light that you don t fully grasp yourself, get help from a book that s both scientifically accurate and entertaining with Light. By combining clear explanations, clever drawings, and activities that use easy-to-find materials, this book covers what science teachers and parents need to know to teach about light with confidence. It uses ray, wave, and particle models of light to explain the basics of reflection and refraction, optical instruments, polarization of light, and interference and diffraction. There s also an entire chapter on how the eye works. Each chapter ends with a Summary and Applications section that reinforces concepts with everyday examples. Whether you need a deeper understanding of how light bends or a good explanation of why the sky is blue, you ll find Light more illuminating and accessible than a college textbook...
Guichon, P A M; Thomas, A W
1996-01-01
We describe the development of a theoretical description of the structure of finite nuclei based on a relativistic quark model of the structure of the bound nucleons which interact through the (self-consistent) exchange of scalar and vector mesons.
Energy Technology Data Exchange (ETDEWEB)
Zerguerras, T
2001-09-01
Proton and two proton emission from light neutron deficient nuclei around A=20 have been studied. A radioactive beam of {sup 18}Ne, {sup 17}F and {sup 20}Mg, produced at the Grand Accelerateur National d'Ions Lourds by fragmentation of a {sup 24}Mg primary beam at 95 MeV/A, bombarded a {sup 9}Be target to form unbound states. Proton(s) and nuclei from the decay were detected respectively in the MUST array and the SPEG spectrometer. From energy and angle measurements, the invariant mass of the decaying nucleus could be reconstructed. Double coincidence events between a proton and {sup 17}F, {sup 16}O, {sup 15}O, {sup 14}O and {sup 18}Ne were registered to obtain excitation energy spectra of {sup 18}Ne, {sup 17}F, {sup 16}F, {sup 15}F et {sup 19}Na. Generally, the masses measures are in agreement with previous experiments. In the case of {sup 18}Ne, excitation energy and angular distributions agree well with the predictions of a break up model calculation. From {sup 17}Ne proton coincidences, a first experimental measurement of the ground state mass excess of {sup 18}Na has been obtained and yields 24,19(0,15)MeV. Two proton emission from {sup 17}Ne and {sup 18}Ne excited states and the {sup 19}Mg ground state was studied through triple coincidences between two proton and {sup 15}O, {sup 16}O and {sup 17}Ne respectively. In the first case, the proton-proton relative angle distribution in the center of mass has been compared with model calculation. Sequential emission from excited states of {sup 17}Ne, above the proton emission threshold, through {sup 16}F is dominant but a {sup 2}He decay channel could not be excluded. No {sup 2}He emission from the 1.288 MeV {sup 17}Ne state, or from the 6.15 MeV {sup 18}Ne state has been observed. Only one coincidence event between {sup 17}Ne and two proton was registered, the value of the one neutron stripping reaction cross section of {sup 20}Mg being much lower than predicted. (author)
Ditchburn, R W
2011-01-01
This classic study, available for the first time in paperback, clearly demonstrates how quantum theory is a natural development of wave theory, and how these two theories, once thought to be irreconcilable, together comprise a single valid theory of light. Aimed at students with an intermediate-level knowledge of physics, the book first offers a historical introduction to the subject, then covers topics such as wave theory, interference, diffraction, Huygens' Principle, Fermat's Principle, and the accuracy of optical measurements. Additional topics include the velocity of light, relativistic o
Energy Technology Data Exchange (ETDEWEB)
Scholl, Clemens
2010-07-07
Excited states in the light nuclei {sup 9}B and {sup 13}C were studied using the ({sup 3}He,t) charge-exchange reaction on {sup 9}Be and {sup 13}C targets. The measurements were performed at the research center for nuclear physics (RCNP) in Osaka, Japan, using the magnetic spectrometer Grand Raiden and the dispersive WS course. The {sup 3}He beam with an energy of 420 MeV was accelerated by the RCNP Ring Cyclotron. The Grand Raiden spectrometer and the WS course allow to study the ({sup 3}He,t) charge-exchange reaction with an energy resolution of around 30 keV, which is one order of magnitude better than measurements with the (p,n) charge-exchange reaction. The high resolution allows to better separate individual states and to determine weak excitation strengths because of low background in the spectra. A total of 19 states in {sup 13}N were studied, and a total of 20 states were observed in {sup 9}B. Of these, 9 states in {sup 13}C and 10 states in {sup 9}B were identified as being excited by a Gamow-Teller transition. Charge-exchange reactions are related to beta-decay, and at zero momentum transfer a simple proportionality exists between the cross-section of the charge-exchange experiment and the Fermi (F) or Gamow-Teller (GT) beta-decay strength. While the Fermi strength B(F) is concentrated in the transition to the isobaric analog state, the Gamow-Teller strength B(GT) is scattered among the excited states. The main aim of the present study is to determine the B(GT) strengths in the nuclei {sup 9}B and {sup 13}N. The only charge-exchange study of {sup 9}B was made 30 years ago with the (p,n) reaction and a resolution of around 300-400 keV. Many states, especially at high excitation energy, could not be resolved by that study. The present work was able to separate many weakly excited states with small decay width at high excitation energies (12-19 MeV) in {sup 9}B and determine the B(GT) strength distribution by using recent high-precision beta-decay data. The
Studies of exotic nuclei; Etudes des noyaux exotiques
Energy Technology Data Exchange (ETDEWEB)
Angelique, J.C.; Orr, N.A. [Lab. de Physique Corpusculaire, Caen Univ., 14 (France); Collaboratio: CATANE (Italy), DAPNIA-Saclay, CSNSM-Orsay, GANIL-Caen, IPN-Orsay, NSCL-MSU (USA), Los Alamos (USA), University of Manchester (United Kingdom), University of Surrey (United Kingdom), FLNR JINR Dubna (Russia), IAP-Bucharest (Romania), NPI-Rez (Czech Republic), CCLRLC-Daresbury (United Kingdom)
1997-12-31
The study of the nuclei far off stability valley is of much interest for testing the nuclear models established for the stable nuclei but also for astrophysics to understand the nucleosynthesis. Experiments aim to measure the mass and lifetime, to build the decay schemes and also to study the structure and the properties of these nuclei. The radioactive beam group focused its research on light neutron-rich nuclei having a halo neutron structure. Mass measurements in N {approx} Z nuclei namely in A {approx} 60-80 proton-rich nuclei, important for understanding the rp process, are mentioned, as well as in nuclei in the {sup 100}Sn region. In the newly obtained {sup 26}O and {sup 28}O nuclei the lifetimes, the probabilities of emission of one for more neutrons were determined. The data analysis has permitted to determine also for the first time the lifetimes of {sup 27,29}F and {sup 30}Ne. Studies of nuclei in the {sup 100}Sn region, near the proton drip line in the ground and isomeric states are now under way. The spectroscopy (energy levels, gamma emissions, etc.) of the neutron-rich nuclei produced by the {sup 36}S fragmentation has been carried out in {sup 31}Ne, {sup 17}B and {sup 29}F. Studies by Coulomb excitation of the 2{sup +} excited states and associated probability B (E2) in O, Ne, Ni and Zn are now analysed 6 refs.
The Scattering of Fast Nucleons from Nuclei
Kerman, A. K.; McManus, H.; Thaler, R. M.
2000-04-01
The formal theory of the scattering of high-energy nucleons by nuclei is developed in terms of the nucleon-nucleon scattering amplitude. The most important approximations necessary to make numerical calculation feasible are then examined. The optical model potential is derived on this basis and compared with the optical model parameters found from experiment. The elastic scattering and polarization of nucleons from light nuclei is predicted and compared with experiment. The effect of nuclear correlations is discussed. The polarization of inelastically scattered nucleons is discussed and predictions compared with experiments. To within the validity of the approximations the experimental data on the scattering of nucleons from nuclei at energies above ˜100 Mev appears to be consistent with the theory.
The scattering of fast nucleons from nuclei
Energy Technology Data Exchange (ETDEWEB)
Kerman, A. K. [Massachusetts Institute of Technology, Cambridge, Massachusetts (United States); McManus, H. [Chalk River Laboratory, Chalk River, Ontario, (Canada); Thaler, R. M. [Los Alamos Scientific Laboratory, Los Alamos, New Mexico (United States)
2000-04-10
The formal theory of the scattering of high-energy nucleons by nuclei is developed in terms of the nucleon nucleon scattering amplitude. The most important approximations necessary to make numerical calculation feasible are then examined. The optical model potential is derived on this basis and compared with the optical model parameters found from experiment. The elastic scattering and polarization of nucleons from light nuclei is predicted and compared with experiment. The effect of nuclear correlations is discussed. The polarization of inelastically scattered nucleons is discussed and predictions compared with experiments. To within the validity of the approximations the experimental data on the scattering of nucleons from nuclei at energies above {approx}100 Mev appears to be consistent with the theory. (c) 2000 Academic Press, Inc.
Electromagnetic and Weak transitions in light nuclei
Energy Technology Data Exchange (ETDEWEB)
M. Viviani; L.E. Marcucci; A. Kievsky; S. Rosati; R. Schiavilla
2002-09-01
Recent advances in the study of the p -- d radiative and mu -- {sup 3}He weak capture processes by our group are presented and discussed. The trinucleon bound and scattering states have been obtained from variational calculations by expanding the corresponding wave functions in terms of correlated hyper-spherical harmonic functions. The electromagnetic and weak transition currents include one- and two-body operators. The accuracy achieved in these calculations allows for interesting comparisons with experimental data.
Coulomb dissociation of light unstable nuclei
Energy Technology Data Exchange (ETDEWEB)
Kido, Toshihiko [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Yabana, Kazuhiro; Suzuki, Yoshiyuki
1997-05-01
The aim of this study is that a simulation method applicable to the atomic nucleus with neutron halo structure developed till now is applied to a wider range unstable nucleus containing proton excess nucleus to also attribute understanding of nuclear reaction with interest in astronomical nuclear reaction. The proton dissociation energy in {sup 8}B nucleus is small value of 138 eV, which is thought to have a structure of proton at the most outer shell bound much weakly by core nucleus and spread in thinner thickness. For the coulomb excitation of such weak bound system, quantum theoretical and non-perturbational treatment is important. Therefore, 3-dimensional time-dependent Schroedinger equation on relative wave function of the core nucleus {sup 7}Be and halo proton p will be dissolved in time space and will execute a time developmental simulation. (G.K.)
Electric dipole moment of light nuclei
Afnan, Iraj R.; Gibson, Benjamin F.
2010-07-01
We examine the sensitivity of the deuteron Electric Dipole Moment (EDM) to variation in the nucleon-nucleon interaction. In particular, we write the EDM as a sum of two terms, one depends on the target wave function, the second on intermediate multiple scattering states in the 3P1 channel. This second contribution is sensitive to off-shell behavior of the 3P1 amplitude.
Electric dipole moment of light nuclei
Energy Technology Data Exchange (ETDEWEB)
Gibson, Benjamin [Los Alamos National Laboratory; Afnan, I R [Los Alamos National Laboratory
2010-01-01
We examine the sensitivity of the deuteron Electric Dipole Moment (EDM) to variation in the nucleon-nucleon interaction. In particular, we write the EDM as a sum of two terms, one depends on the target wave function, the second on intermediate multiple scattering states in the {sup 3}P{sub 1} channel. This second contribution is sensitive to off-shell behavior of the {sup 3}P{sub 1} amplitude.
Electric dipole moment of light nuclei
Energy Technology Data Exchange (ETDEWEB)
Gibson, Benjamin [Los Alamos National Laboratory; Afnan, I R [Los Alamos National Laboratory
2010-01-01
We examine the sensitivity of the deuteron Electric Dipole Moment (EDM) to variation in the nucleon-nucleon interaction. In particular, we write the EDM as a sum of two terms, one depends on the target wave function, the second on intermediate multiple scattering states in the {sup 3}P{sub 1} channel. This second contribution is sensitive to off-shell behavior of the {sup 3}P{sub 1} amplitude.
Radiative muon capture in light nuclei
Energy Technology Data Exchange (ETDEWEB)
Hasinoff, M.D.; Ahmad, S; Armstrong, D.S.; Azuelos, G.; Bertl, W.; Blecher, M.; Burnham, R.A.; Clifford, E.T.H.; Chen, C.Q.; Ding, Z.H.; Depommier, P.; Gorringe, T.P.; Henderson, R.; Larabee, A.J.; Macdonald, J.A.; Mes, H.; Numao, T.; Poutissou, J.M.; Poutissou, R.; Robertson, B.C.; Serna-Angel, A.; Summhammer, J.; Taylor, G.N.; Waltham, C.E.; Wright, D.H.; Zhang, N.S.; MacDonald, S.C. (British Columbia Univ., Vancouver,
1989-06-01
Radiative muon capture rates have been measured for carbon, oxygen and calcium targets. The carbon and oxygen rates yield large values for g{sub p} when compared to detailed microscopic calculations but the conventional Goldberger-Treiman value when compared to phenomenological model calculations. A progress report on the TRIUMF RMC measurement on hydrogen is also given. 16 refs., 2 figs., 1 tab.
Annihilation of Antiprotons in Light Nuclei
Institute of Scientific and Technical Information of China (English)
M. A. Rana; E. U. Khan; M. I. Shahzad; I. E. Qureshi; F. Malik; G. Sher; S. Manzoor; H. A. Khan
2006-01-01
@@ CR-39 detectors have been exposed to a 5.9-MeV antiproton beam using the low energy antiproton ring (LEAR) facility at CERN. At this energy, tracks of antiprotons appear in a CR-39 detector after 135 min of etching in 6 M NaOH at 70℃ . Fluence of the antiproton beam has been determined using track density. We have also found tracks in the etched CR-39 detector at different depths (250-500μm). These tracks have resulted from the annihilation of antiprotons with the constituents (H, C and O) of the CR-39 detector. The goal of the experiment is to develop a simple and low-cost method to study properties of antiparticles and those formed after annihilation of these particles with the target matter.
Anharmonic vibrations in nuclei
Fallot, M; Andrés, M V; Catara, F; Lanza, E G; Scarpaci, J A; Chomaz, Ph.
2003-01-01
In this letter, we show that the non-linearitites of large amplitude motions in atomic nuclei induce giant quadrupole and monopole vibrations. As a consequence, the main source of anharmonicity is the coupling with configurations including one of these two giant resonances on top of any state. Two-phonon energies are often lowered by one or two MeV because of the large matrix elements with such three phonon configurations. These effects are studied in two nuclei, 40Ca and 208Pb.
Directory of Open Access Journals (Sweden)
Marie Pancera
Full Text Available Dozens of broadly neutralizing HIV-1 antibodies have been isolated in the last few years from the sera of HIV-1-infected individuals. Only a limited number of regions on the HIV-1 spike, however, are recognized by these antibodies. One of these regions (N332 is characterized by an N-linked glycan at residue 332 on HIV-1 gp120 and is recognized by antibody 2G12 and by the recently reported antibodies PGT121-137, the latter isolated from three donors. To investigate the diversity in mode of antibody recognition at the N332 site, we used functional complementation between antibody heavy and light chains as a means of assessing similarity in mode of recognition. We examined a matrix of 12 PGT-heavy chains with each of 12 PGT-light chains. Expression in 96-well format for the 144 antibodies (132 chimeric and 12 wild-type was generally consistent (58 ± 10 µg/ml. In contrast, recognition of HIV-1 gp120 was bimodal: when the source of heavy and light chains was from the same donor, recognition was good; when sources of heavy and light chains were from different donors, recognition was poor. Moreover, neutralization of HIV-1 strains SF162.LS and TRO.11 generally followed patterns of gp120 recognition. These results are consistent with published sequence, mutational, and structural findings, all of which indicate that N332-directed neutralizing antibodies from different donors utilize different modes of recognition, and provide support for a correlation between functional complementation of antibody heavy and light chains and similarity in antibody mode of recognition. Overall, our results add to the growing body of evidence that the human immune system is capable of recognizing the N332-region of HIV-1 gp120 in diverse ways.
Perception, illusions and Bayesian inference.
Nour, Matthew M; Nour, Joseph M
2015-01-01
Descriptive psychopathology makes a distinction between veridical perception and illusory perception. In both cases a perception is tied to a sensory stimulus, but in illusions the perception is of a false object. This article re-examines this distinction in light of new work in theoretical and computational neurobiology, which views all perception as a form of Bayesian statistical inference that combines sensory signals with prior expectations. Bayesian perceptual inference can solve the 'inverse optics' problem of veridical perception and provides a biologically plausible account of a number of illusory phenomena, suggesting that veridical and illusory perceptions are generated by precisely the same inferential mechanisms.
Elusive active galactic nuclei
Maiolino, R; Comastri, A; Gilli, R; Nagar, NM; Bianchi, S; Boker, T; Colbert, E; Krabbe, A; Marconi, A; Matt, G; Salvati, M
2003-01-01
A fraction of active galactic nuclei do not show the classical Seyfert-type signatures in their optical spectra, i.e. they are optically 'elusive'. X-ray observations are an optimal tool to identify this class of objects. We combine new Chandra observations with archival X-ray data in order to obtai
Shape Deformations in Atomic Nuclei
Hamamoto, Ikuko
2011-01-01
The ground states of some nuclei are described by densities and mean fields that are spherical, while others are deformed. The existence of non-spherical shape in nuclei represents a spontaneous symmetry breaking.
Clustering in stable and exotic nuclei
Beck, C
2016-01-01
Since the pioneering discovery of molecular resonances in the 12C+12C reaction more than half a century ago a great deal of research work has been undertaken in alpha clustering. Our knowledge on physics of nuclear molecules has increased considerably and nuclear clustering remains one of the most fruitful domains of nuclear physics, facing some of the greatest challenges and opportunities in the years ahead. The occurrence of "exotic" shapes and Bose-Einstein alpha condensates in light N=Z alpha-conjugate nuclei is investigated. Various approaches of the superdeformed and hyperdeformed bands associated with quasimolecular resonant structures are presented. Evolution of clustering from stability to the drip-lines is examined: clustering aspects are, in particular, discussed for light exotic nuclei with large neutron excess such as neutron-rich Oxygen isotopes with their complete spectroscopy.
Ultra High Energy Nuclei Propagation
Aloisio, Roberto
2008-01-01
We discuss the problem of ultra high energy nuclei propagation in astrophysical backgrounds. We present a new analytical computation scheme based on the hypothesis of continuos energy losses in a kinetic formulation of the particles propagation. This scheme enables the computation of the fluxes of ultra high energy nuclei as well as the fluxes of secondaries (nuclei and nucleons) produced by the process of photo-disintegration suffered by nuclei.
Inferring attitudes from mindwandering.
Critcher, Clayton R; Gilovich, Thomas
2010-09-01
Self-perception theory posits that people understand their own attitudes and preferences much as they understand others', by interpreting the meaning of their behavior in light of the context in which it occurs. Four studies tested whether people also rely on unobservable "behavior," their mindwandering, when making such inferences. It is proposed here that people rely on the content of their mindwandering to decide whether it reflects boredom with an ongoing task or a reverie's irresistible pull. Having the mind wander to positive events, to concurrent as opposed to past activities, and to many events rather than just one tends to be attributed to boredom and therefore leads to perceived dissatisfaction with an ongoing task. Participants appeared to rely spontaneously on the content of their wandering minds as a cue to their attitudes, but not when an alternative cause for their mindwandering was made salient.
Gamma-Rays from Heavy Nuclei Accelerated in Supernova Remnants
Caprioli, D; Amato, E
2010-01-01
We investigate the theoretical and observational implications of the acceleration of protons and heavier nuclei in supernova remnants (SNRs). By adopting a semi-analytical technique, we study the non-linear interplay among particle acceleration, magnetic field generation and shock dynamics, outlining a self-consistent scenario for the origin of the spectrum of Galactic cosmic rays as produced in this class of sources. Moreover, the inferred chemical abundances suggest nuclei heavier than Hydrogen to be relevant not only in the shock dynamics but also in the calculation of the gamma-ray emission from SNRs due to the decay of neutral pions produced in nuclear interactions.
Energy Technology Data Exchange (ETDEWEB)
Legoll, F. [Service de Physique Theorique, CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France)
1998-07-22
For nuclei with very high electrical charge, the Coulomb field is expected to drive the protons away from the centre to the surface of the nucleus. Such a nucleus would be no more compact but look like a bubble. The goal of this work is to confirm this idea. We are interested in only the ground state of spherical nuclei. We use the Skyrme potential with the Sly4 parametrization to calculate the mean-field Hamiltonian. Paring correlations are described by a surface-active delta paring interaction. In its ground state the nucleus {sup A=900} X{sub Z=274} is shown to be a bubble. Another stable state is found with a little higher energy: it is also a bubble. (author) 11 refs., 18 figs., 33 tabs.
Energy Technology Data Exchange (ETDEWEB)
Legoll, F. [Service de Physique Theorique, CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France)
1998-07-22
For nuclei with very high electrical charge, the Coulomb field is expected to drive the protons away from the centre to the surface of the nucleus. Such a nucleus would be no more compact but look like a bubble. The goal of this work is to confirm this idea. We are interested in only the ground state of spherical nuclei. We use the Skyrme potential with the Sly4 parametrization to calculate the mean-field Hamiltonian. Paring correlations are described by a surface-active delta paring interaction. In its ground state the nucleus {sup A=900} X{sub Z=274} is shown to be a bubble. Another stable state is found with a little higher energy: it is also a bubble. (author) 11 refs., 18 figs., 33 tabs.
Krumholz, Mark R; da Silva, Robert L; Rendahl, Theodore; Parra, Jonathan
2015-01-01
Stellar population synthesis techniques for predicting the observable light emitted by a stellar population have extensive applications in numerous areas of astronomy. However, accurate predictions for small populations of young stars, such as those found in individual star clusters, star-forming dwarf galaxies, and small segments of spiral galaxies, require that the population be treated stochastically. Conversely, accurate deductions of the properties of such objects also requires consideration of stochasticity. Here we describe a comprehensive suite of modular, open-source software tools for tackling these related problems. These include: a greatly-enhanced version of the slug code introduced by da Silva et al. (2012), which computes spectra and photometry for stochastically- or deterministically-sampled stellar populations with nearly-arbitrary star formation histories, clustering properties, and initial mass functions; cloudy_slug, a tool that automatically couples slug-computed spectra with the cloudy r...
Van Isacker, P
2010-01-01
The use of dynamical symmetries or spectrum generating algebras for the solution of the nuclear many-body problem is reviewed. General notions of symmetry and dynamical symmetry in quantum mechanics are introduced and illustrated with simple examples such as the SO(4) symmetry of the hydrogen atom and the isospin symmetry in nuclei. Two nuclear models, the shell model and the interacting boson model, are reviewed with particular emphasis on their use of group-theoretical techniques.
Kelkar, N G; Moskal, P
2015-01-01
The possibility for the existence of unstable bound states of the S11 nucleon resonance N$^*$(1535) and nuclei is investigated. These quasibound states are speculated to be closely related to the existence of the quasibound states of the eta mesons and nuclei. Within a simple model for the N N$^*$ interaction involving a pion and eta meson exchange, N$^*$-nucleus potentials for N*-$^3$He and N*-$^{24}$Mg are evaluated and found to be of a Woods-Saxon like form which supports two to three bound states. In case of N*-$^3$He, one state bound by only a few keV and another by 4 MeV is found. The results are however quite sensitive to the N N$^*$ $\\pi$ and N N$^*$ $\\eta$ vertex parameters. A rough estimate of the width of these states, based on the mean free path of the exchanged mesons in the nuclei leads to very broad states with $\\Gamma \\sim$ 80 and 110 MeV for N*-$^3$He and N*-$^{24}$Mg respectively.
Relativistic Mean Field Study on Halo Structures of Mirror Nuclei
Institute of Scientific and Technical Information of China (English)
LIANG Yu-Jie; LI Yan-Song; LIU Zu-Hua; ZHOU Hong-Yu
2009-01-01
Halo structures of some light mirror nuclei are investigated with the relativistic mean field (RMF) theory.The calculations show that the dispersion of the valence proton is larger than that of the valence neutron in its mirror nucleus,the difference between the root-mean-square (rms) radius of the valence nucleon in each pair of mirror nuclei becomes smailer with the increase of the mass number A,and all the ratios of the rms radius of the valence nucleon to that of the matter in each pair o~ mirror nuclei decrease almost linearly with the increase of the mass number A.
Detecting and Identifying Heavy Nuclei and Antinuclei with Standard Detectors
Swain, J; Widom, A; Srivastava, Y N
2011-01-01
Most data gathered from high energy experiments at colliders are analyzed assuming that particles stable enough to not decay in the detector volume, and able to interact strongly or electromagnetically, must be electrons, muons, protons, neutrons, photons, kaons, and charged pions, or their antiparticles. While light nuclei and antinuclei such as (anti)deuterons have been detected, we argue that it is experimentally interesting to look for even heavier nuclei in high energy collisions. To this end, we point out that using only tracking and calorimetry information it is, in principle, possible to also search for high energy nuclei and antinuclei and determine, with errors, their charge Z and atomic weight A.
The intergalactic propagation of ultrahigh energy cosmic ray nuclei
Energy Technology Data Exchange (ETDEWEB)
Hooper, Dan; /Fermilab; Sarkar, Subir; /Oxford U., Theor. Phys.; Taylor, Andrew M.; /Oxford U.
2006-08-01
We investigate the propagation of ultra-high energy cosmic ray nuclei (A = 1-56) from cosmologically distant sources through the cosmic radiation backgrounds. Various models for the injected composition and spectrum and of the cosmic infrared background are studied using updated photodisintegration cross-sections. The observational data on the spectrum and the composition of ultra-high energy cosmic rays are jointly consistent with a model where all of the injected primary cosmic rays are iron nuclei (or a mixture of heavy and light nuclei).
Quantum-Information Content of Fractional Occupation Probabilities in Nuclei
Chatzisavvas, K C
2004-01-01
Three measures of the information content of a probability distribution are briefly reviewed. They are applied to fractional occupation probabilities in light nuclei, taking into account short-range correlations. The effect of short-range correlations is to increase the information entropy (or disorder) of nuclei, comparing with the independent particle model. It is also indicated that the information entropy can serve as a sensitive index of order and short-range correlations in nuclei. It is concluded that increasing $Z$, the information entropy increases i.e. the disorder of the nucleus increases for all measures of information considered in the present work.
Battye, R. A.; Manton, N. S.; Sutcliffe, P. M.
We review recent work on the modelling of atomic nuclei as quantised Skyrmions, using Skyrme's original model with pion fields only. Skyrmions are topological soliton solutions, whose conserved topological charge B is identified with the baryon number of a nucleus. Apart from an energy and length scale, the Skyrme model has just one dimensionless parameter m, proportional to the pion mass. It has been found that a good fit to experimental nuclear data requires m to be of order 1. The Skyrmions for B up to 7 have been known for some time, and are qualitatively insensitive to whether m is zero or of order 1. However, for baryon numbers B = 8 and above, the Skyrmions have quite a compact structure for m of order 1, rather than the hollow polyhedral structure found when m = 0. One finds for baryon numbers which are multiples of four, that the Skyrmions are composed of B = 4 sub-units, as in the α-particle model of nuclei. The rational map ansatz gives a useful approximation to the Skyrmion solutions for all baryon numbers when m = 0. For m of order 1, it gives a good approximation for baryon numbers up to 7, and generalisations of this ansatz are helpful for higher baryon numbers. We briefly review the work from the 1980s and 90s on the semiclassical rigidbody quantisation of Skyrmions for B = 1, 2, 3 and 4. We then discuss more recent work extending this method to B = 6, 7, 8, 10 and 12. We determine the quantum states of the Skyrmions, finding their spins, isospins and parities, and compare with the experimental data on the ground and excited states of nuclei up to mass number 12.
Beckmann, Volker
2012-01-01
This AGN textbook includes phenomena based on new results in the X-Ray domain from new telescopes such as Chandra and XMM Newton not mentioned in any other book. Furthermore, it considers also the Fermi Gamma Ray Space Telescope with its revolutionary advances of unprecedented sensitivity, field of view and all-sky monitoring. Those and other new developments as well as simulations of AGN merging events and formations, enabled through latest super-computing capabilities. The book gives an overview on the current knowledge of the Active Galacitc Nuclei phenomenon. The spectral energy d
Blandford, RD; Woltjer, L
1990-01-01
Starting with this volume, the Lecture Notes of the renowned Advanced Courses of the Swiss Society for Astrophysics and Astronomy will be published annually. In each course, three extensive lectures given by leading experts in their respective fields cover different and essential aspects of the subject. The 20th course, held at Les Diablerets in April 1990, dealt with current research on active galactic nuclei; it represents the most up-to-date views on the subject, presented with particular regard for clarity. The previous courses considered a wide variety of subjects, beginning with ""Theory
Energy Technology Data Exchange (ETDEWEB)
Ney, E.P.
1982-01-22
Photography of the nucleus of comet Halley is the goal of several planned space missions. The nucleus of a comet is surrounded by a cloud of dust particles. If this cloud is optically thick, it will prevent observation of the nuclear surface. Broadband photometry of nine comets has been analyzed to determine the visibility of their nuclei. Only in the case of comet West near perihelion was the dust dense enough to interfere with imaging. Comparison of the visual brightness of the well-observed comets with that of Halley in 1910 leads to the conclusion that the nucleus of Halley can be imaged without significant obscuration by the dust.
Elusive Active Galactic Nuclei
Maiolino, R; Gilli, R; Nagar, N M; Bianchi, S; Böker, T; Colbert, E; Krabbe, A; Marconi, A; Matt, G; Salvati, M
2003-01-01
A fraction of active galactic nuclei do not show the classical Seyfert-type signatures in their optical spectra, i.e. they are optically "elusive". X-ray observations are an optimal tool to identify this class of objects. We combine new Chandra observations with archival X-ray data in order to obtain a first estimate of the fraction of elusive AGN in local galaxies and to constrain their nature. Our results suggest that elusive AGN have a local density comparable to or even higher than optically classified Seyfert nuclei. Most elusive AGN are heavily absorbed in the X-rays, with gas column densities exceeding 10^24 cm^-2, suggesting that their peculiar nature is associated with obscuration. It is likely that in elusive AGN, the nuclear UV source is completely embedded and the ionizing photons cannot escape, which prevents the formation of a classical Narrow Line Region. Elusive AGN may contribute significantly to the 30 keV bump of the X-ray background.
Electron scattering for exotic nuclei
Indian Academy of Sciences (India)
Toshimi Suda
2014-11-01
A brand-new electron scattering facility, the SCRIT Electron Scattering Facility, will soon start its operation at RIKEN RI Beam Factory, Japan. This is the world’s first electron scattering facility dedicated to the structure studies of short-lived nuclei. The goal of this facility is to determine the charge density distributions of short-lived exotic nuclei by elastic electron scattering. The first collision between electrons and exotic nuclei will be observed in the year 2014.
Octupole correlations in the odd-[ital Z] nuclei [sup 148-151]Eu
Energy Technology Data Exchange (ETDEWEB)
Jongman, J.R.; Bacelar, J.C.S.; Urban, W.; Noorman, R.F.; van Pol, J.; Steenbergen, T.; de Voigt, M.J.A. (Kernfysisch Versneller Instituut, 9747 AA Groningen (Netherlands)); Nyberg, J.; Sletten, G. (Neils Bohr Institute, Riso, 4000 Roskilde (Denmark)); Dionisio, J.; Vieu, C. (Centre de Spectrometrie Nucleaire et Spectrometrie de Masse, 91405 Orsay (France))
1994-12-01
The effects of octupole correlations in the [ital Z]=63 nuclei [sup 148[minus]151]Eu are studied. The persistency of octupole instability through the transitional region of near-spherical ([ital N][le]85) towards prolate nuclei ([ital N][ge]88) is established and discussed. Intrinsic dipole moments, which are experimentally inferred from the measured electric dipole transition rates observed between parity doublets, are used to characterize the strength of the octupole correlations.
Ayala, A P; Levin, E M
1996-01-01
In this talk we present our detail study ( theory and numbers) [1] on the shadowing corrections to the gluon structure functions for nuclei. Starting from rather contraversial information on the nucleon structure function which is originated by the recent HERA data, we develop the Glauber approach for the gluon density in a nucleus based on Mueller formula [2] and estimate the value of the shadowing corrections in this case. Than we calculate the first corrections to the Glauber approach and show that these corrections are big. Based on this practical observation we suggest the new evolution equation which takes into account the shadowing corrections and solve it. We hope to convince you that the new evolution equation gives a good theoretical tool to treat the shadowing corrections for the gluons density in a nucleus and, therefore, it is able to provide the theoretically reliable initial conditions for the time evolution of the nucleus - nucleus cascade.
Xu, Renxin
2011-01-01
What is the real nature of pulsars? This is essentially a question of the fundamental strong interaction between quarks at low-energy scale and hence of the non-perturbative quantum chromo-dynamics, the solution of which would certainly be meaningful for us to understand one of the seven millennium prize problems (i.e., "Yang-Mills Theory") named by the Clay Mathematical Institute. After a historical note, it is argued here that a pulsar is very similar to an extremely big nucleus, but is a little bit different from the {\\em gigantic nucleus} speculated 80 years ago by L. Landau. The paper demonstrates the similarity between pulsars and gigantic nuclei from both points of view: the different manifestations of compact stars and the general behavior of the strong interaction.
Nucleomorphs: enslaved algal nuclei.
Cavalier-Smith, T
2002-12-01
Nucleomorphs of cryptomonad and chlorarachnean algae are the relict, miniaturised nuclei of formerly independent red and green algae enslaved by separate eukaryote hosts over 500 million years ago. The complete 551 kb genome sequence of a cryptomonad nucleomorph confirms that cryptomonads are eukaryote-eukaryote chimeras and greatly illuminates the symbiogenetic event that created the kingdom Chromista and their alveolate protozoan sisters. Nucleomorph membranes may, like plasma membranes, be more enduring after secondary symbiogenesis than are their genomes. Partial sequences of chlorarachnean nucleomorphs indicate that genomic streamlining is limited by the mutational difficulty of removing useless introns. Nucleomorph miniaturisation emphasises that selection can dramatically reduce eukaryote genome size and eliminate most non-functional nuclear non-coding DNA. Given the differential scaling of nuclear and nucleomorph genomes with cell size, it follows that most non-coding nuclear DNA must have a bulk-sequence-independent function related to cell volume.
Collective excitations in nuclei
Energy Technology Data Exchange (ETDEWEB)
Chomaz, Ph. [Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France); Collaboration: La Direction des Sciences de la Matiere du CEA (FR); Le Fonds National de la Recherche Scientifique de Belgique (BE)
1998-12-31
The properties of the nucleus cannot be reduced to the properties of its constituents: it is a complex system. The fact that many properties of the nucleus are consequences of the existence of mean-field potential is a manifestation of this complexity. In particular, the nucleons can thus self-organize in collective motions such as giant resonances. Therefore the study of this collective motions is a very good tool to understand the properties of the nucleus itself. The purpose of this article is to stress some aspects of these collective vibrations. We have studied how an ensemble of fermions as the nucleus can self-organize in collective vibrations which are behaving like a gas of bosons in weak interaction. Understanding of these phenomena remains one of the important subjects of actuality in the context of quantal systems in strong interaction. In particular, the study of the states with one or two vibration quanta provides a direct information on the structure of nuclei close to their ground states. Moreover, some collective states appear to be very robust against the onset of chaos. This is the case of the hot giant dipole built on top of a hot nucleus which seems to survive up to rather high temperatures. Their sudden disappearance is still a subject of controversy. It may be that the mean-field and the associated collective states are playing a crucial role also in catastrophic processes such as the phase-transitions. Indeed, when the system is diluted the collective vibrations may become unstable and it seems that these unstable modes provide a natural explanation to the self organization of the system in drops. Finally, considering the diversity of the different structures of exotic nuclei one may expect new vibration types. All these studies are showing the diversity of the collective motions of strongly correlated quantum systems such as the nucleus but many open questions remain to be solved. (authors) 304 refs., 53 figs., 5 tabs.
The morphology of cometary nuclei
Keller, H. U.; Jorda, L.
the Rosetta comet rendezvous mission) to about 50 km (comet Hale- Bopp, comet P/Schwassman-Wachmann 1). Their albedos are very low, about 0.04. Their shapes are irregular, axes ratios of 2:1 are often derived. Even though comets are characterized by their activity, in most cases only a small fraction of the nuclear surface (in some cases less than 1%) is active. An exception seems to be comet P/Wirtanen where all its surface is required to be active in order to explain its production rates (Rickman and Jorda 1998). The detection of trans-Neptunian objects (TNOs) in the Kuiper belt (Jewitt and Luu 1993) reveals a new population of cometary bodies with dimensions an order of magnitude bigger (100 km and larger) than the typical comet observed in the inner planetary system. Little is known about the extent, density, size distribution and physical characteristics of these objects. This region is supposedly the reservoir for short-period comets, manly those controlled by Jupiter (Jupiter family comets). Our present concept of a cometary nucleus has been strongly influenced by the first pictures of the nucleus of comet Halley achieved during the Giotto flyby in 1986. While this revelation seems to be confirmed as typical by modern observations it carries the danger of prototyping new observational results and inferences. Missions and spacecraft are already on their way (Deep Space, Contour, Stardust, Deep Impact) or in preparation (Rosetta) to diversify our knowledge. The morphology of cometary nuclei is determined by their formation process in the early solar nebula, their dynamics and evolution. The physics of the processes leading to their apparent activity while approaching the Sun are still obscure in many details but determine the small- and intermediate-scale morphology. The large-scale morphology, the shape, of a cometary nucleus is determined by its fragility and inner structure and by its generally complex rotational state. These topics will be reviewed in the
Cavitation inception from bubble nuclei
DEFF Research Database (Denmark)
Mørch, Knud Aage
2015-01-01
, and experimental investigations of bubbles and cavitation inception have been presented. These results suggest that cavitation nuclei in equilibrium are gaseous voids in the water, stabilized by a skin which allows diffusion balance between gas inside the void and gas in solution in the surrounding liquid....... The cavitation nuclei may be free gas bubbles in the bulk of water, or interfacial gaseous voids located on the surface of particles in the water, or on bounding walls. The tensile strength of these nuclei depends not only on the water quality but also on the pressure-time history of the water. A recent model......The tensile strength of ordinary water such as tap water or seawater is typically well below 1 bar. It is governed by cavitation nuclei in the water, not by the tensile strength of the water itself, which is extremely high. Different models of the nuclei have been suggested over the years...
DEFF Research Database (Denmark)
Andersen, Jesper
2009-01-01
Collateral evolution the problem of updating several library-using programs in response to API changes in the used library. In this dissertation we address the issue of understanding collateral evolutions by automatically inferring a high-level specification of the changes evident in a given set ...... specifications inferred by spdiff in Linux are shown. We find that the inferred specifications concisely capture the actual collateral evolution performed in the examples....
New measurements of high-momentum nucleons and short-range structures in nuclei
Fomin, N; Asaturyan, R; Benmokhtar, F; Boeglin, W; Bosted, P; Bruell, A; Bukhari, M H S; Chudakov, E; Clasie, B; Connell, S H; Dalton, M M; Daniel, A; Day, D B; Dutta, D; Ent, R; Fassi, L El; Fenker, H; Filippone, B W; Garrow, K; Gaskell, D; Hill, C; Holt, R J; Horn, T; Jones, M K; Jourdan, J; Kalantarians, N; Keppel, C E; Kiselev, D; Kotulla, M; Lindgren, R; Lung, A F; Malace, S; Markowitz, P; McKee, P; Meekins, D G; Mkrtchyan, H; Navasardyan, T; Niculescu, G; Opper, A K; Perdrisat, C; Potterveld, D H; Punjabi, V; Qian, X; Reimer, P E; Roche, J; Rodriguez, V M; Rondon, O; Schulte, E; Seely, J; Segbefia, E; Slifer, K; Smith, G R; Solvignon, P; Tadevosyan, V; Tajima, S; Tang, L; Testa, G; Trojer, R; Tvaskis, V; Vulcan, W F; Wasko, C; Wesselmann, F R; Wood, S A; Wright, J; Zheng, X
2011-01-01
We present new, high-Q^2 measurements of inclusive electron scattering from high-momentum nucleons in nuclei. This yields an improved extraction of the strength of two-nucleon correlations for several nuclei, including light nuclei where clustering effects can, for the first time, be examined. The data extend to the kinematic regime where three-nucleon correlations are expected to dominate and we observe significantly greater strength in this region than previous measurements.
Superheavy nuclei – cold synthesis and structure
Indian Academy of Sciences (India)
Raj K Gupta
2001-08-01
The quantum mechanical fragmentation theory (QMFT), given for the cold synthesis of new and superheavy elements, is reviewed and the use of radioactive nuclear beams (RNB) and targets (RNT) is discussed. The QMFT is a complete theory of cold nuclear phenomena, namely, the cold ﬁssion, cold fusion and cluster radioactivity. Also, the structure calculations based on the axially deformed relativistic mean ﬁeld (DRMF) approach are presented which predict new regions of spherical magicity, namely = 120 and = 172 or 184, for superheavy nuclei. This result is discussed in the light of recent experiments reporting the cold synthesis of = 118 element.
Reactions and structure of exotic nuclei
Energy Technology Data Exchange (ETDEWEB)
Esbensen, H.
1993-08-01
Radioactive beam experiments have made it possible to study the structure of light neutron rich nuclei. A characteristic feature is a large dipole strength near threshold. An excellent example is the loosely bound nucleus ``Li for which Coulomb dissociation plays a dominant role in breakup reactions on a high Z target. I will describe a three-body model and apply it to calculate the dipole response of {sup 11}Li and the momentum distributions for the three-body breakup reaction: {sup 11}Li {yields} {sup 9}Li+n+n, and comparisons will be made to recent three-body coincidence measurements.
The cochlear nuclei of snakes.
Miller, M R
1980-08-15
The cochlear nuclei of three burrowing snakes (Xenopeltis unicolor, Cylindrophis rufus, and Eryx johni) and three non-burrowing snakes (Epicrates cenchris, Natrix sipedon, and Pituophis catenifer) were studied. The posterior branch of the statoacoustic nerve and its posterior ganglion were destroyed and the degenerated nerve fibers and terminals traced to primary cochlear nuclei in 13 specimens of Pituophis catenifer. All these snake species possess three primary and one secondary cochlear nuclei. The primary cochlear nuclei consist of a small nucleus angularis located at the cerebello-medullary junction and a fairly large nucleus magnocellularis forming a dorsal cap over the cephalic end of the alar eminence. Nucleus magnocellularis may be subdivided into a medially placed group of rounder cells, nucleus magnocellularis medialis, and a laterally placed group of more ovate and paler-staining cells, nucleus magnocellularis lateralis. A small but well-defined secondary nucleus which showed no degenerated nerve terminals after nerve root section, nucleus laminaris, underlies the cephalic part of both nucleus magnocellularis medialis and nucleus magnocellularis lateralis. Larger and better-developed cochlear nuclei were found in burrowing species than in non-burrowing species of snakes. Of the three burrowing species studied, Xenopeltis showed the greatest development of cochlear nuclei; Eryx cochlear nuclei were not quite as large but were better differentiated than in Xenopeltis; and Cylindrophis cochlear nuclei were fairly large but not as well developed nor as well differentiated as in either Xenopeltis or Eryx. The cochlear nuclei of the three non-burrowing snakes, Epicrates, Natrix, and Pituophis, were not as large nor as well developed as those of the burrowing snakes. There is some, but not complete, correlation between cochlear development and papilla basilaris length and number of hair cells. Thus, Xenopeltis and Eryx, with well-developed cochlear nuclei
Collective excitations in nuclei
Energy Technology Data Exchange (ETDEWEB)
Chomaz, Ph
1997-12-31
The properties of the nucleus cannot be reduced to the properties of its constituents: it is a complex system. The fact that many properties of the nucleus are consequences of the existence of mean-field potential is a manifestation of this complexity. In particular the nucleons can thus self-organize in collective motions such as giant resonances. Therefore the study of these collective motions is a very good to understand the properties of the nucleus itself. The purpose of this article was to stress some aspects of these collective vibrations. In particular we have studied how an ensemble of fermions as the nucleus can self-organize in collective vibrations which are behaving like a gas of bosons in weak interaction. The understanding of these phenomena remains one of the important subjects of actually in the context of quantal systems in strong interaction. In particular the study of the states with one or two vibration quanta provides a direct information on the structure if nuclei close to their ground states. (author) 270 refs.
Energy Technology Data Exchange (ETDEWEB)
Ayala, A.L. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Fisica][Pelotas Univ., RS (Brazil). Inst. de Fisica e Matematica; Ducati, M.B.G. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Fisica; Levin, E.M. [Fermi National Accelerator Lab., Batavia, IL (United States)][Nuclear Physics Inst., St. Petersburg (Russian Federation)
1996-10-01
In this talk we present our detailed study (theory and numbers) on the shadowing corrections to the gluon structure functions for nuclei. Starting from rather controversial information on the nucleon structure function which is originated by the recent HERA data, we develop the Glauber approach for the gluon density in a nucleus based on Mueller formula and estimate the value of the shadowing corrections in this case. Then we calculate the first corrections to the Glauber approach and show that these corrections are big. Based on this practical observation we suggest the new evolution equation which takes into account the shadowing corrections and solve it. We hope to convince you that the new evolution equation gives a good theoretical tool to treat the shadowing corrections for the gluons density in a nucleus and, therefore, it is able to provide the theoretically reliable initial conditions for the time evolution of the nucleus-nucleus cascade. The initial conditions should be fixed both theoretically and phenomenologically before to attack such complicated problems as the mixture of hard and soft processes in nucleus-nucleus interactions at high energy or the theoretically reliable approach to hadron or/and parton cascades for high energy nucleus-nucleus interaction. 35 refs., 24 figs., 1 tab.
Energy Technology Data Exchange (ETDEWEB)
Petrov, S.
1996-10-01
Languages with a solvable implication problem but without complete and consistent systems of inference rules (`poor` languages) are considered. The problem of existence of finite complete and consistent inference rule system for a ``poor`` language is stated independently of the language or rules syntax. Several properties of the problem arc proved. An application of results to the language of join dependencies is given.
Description of Superdeformed Bands of the Nuclei in A ～ 60 Mass Region
Institute of Scientific and Technical Information of China (English)
刘玉鑫; 孟祥明
2003-01-01
Using the supersymmetry scheme including many-body interactions, we investigate the superdeformed (SD) bands of the nuclei in A ～ 60 mass region systematically. Quantitatively good results of the γ-ray energy spectra and the dynamical moments of inertia are obtained. It shows that the supersymmetry approach is powerful to describe the generic rotational property of SD states of light nuclei.
Status and Perspectives of the Search for Eta-Mesic Nuclei
Moskal, Pawel; Krzemien, Wojciech
2016-01-01
In this report the search for eta-mesic nuclei is reviewed. The brief description of the experimental studies is presented with a focus on the possible production of the eta-nucleus bound states for light nuclei like 4He and 3He.
Monopole transitions in hot nuclei
Energy Technology Data Exchange (ETDEWEB)
Sujkowski, Z. [Soltan Inst. for Nuclear Studies, Otwock-Swierk (Poland)
1994-12-31
Monopole transitions can be a signature of shape changing in a hot, pulsating nucleus (the low energy E0 mode) and/or a measure of the compressibility of finite nuclei (GMR, the breathing mode). Experimental information pertaining to GMR is reviewed. Recipes for deducing the incompressibility modules for infinite nuclear matter from data on GMR are discussed. Astrophysical implications are outlined. The first attempts at locating the GMR strength in moderately hot nuclei are described. Prospects for improving the experimental techniques to make an observation of this strength in selected nuclei unambiguous are discussed. (author). 46 refs, 8 figs.
Spectroscopy of heavy fissionable nuclei
Indian Academy of Sciences (India)
S K Tandel
2015-09-01
Structural studies of heavy nuclei are quite challenging due to increased competition from fission, particularly at high spins. Nuclei in the actinide region exhibit a variety of interesting phenomena. Recent advances in instrumentation and analysis techniques have made feasible sensitive measurements of nuclei populated with quite low cross-sections. These include isomers and rotational band structures in isotopes of Pu ( = 94) to Rf ( = 104), and octupole correlations in the Th ( = 90) region. The obtained experimental data have provided insights on various aspects like moments of inertia and nucleon alignments at high spins, quasiparticle energies and evolution of quadrupole and octupole collectivity, among others. An overview of some of these results is presented.
Statistical Spectroscopy for Neutron-rich sd-Shell Nuclei
Kar, Kamales
2012-01-01
Statistical spectroscopic results using the spectral distribution theory are obtained for the structure of neutron-rich light nuclei going towards the drip line and compared to experimental values available. These results will be useful for nuclear astrophysics problems where often averaged nuclear properties are adequate.
Pseudospin Dynamical Symetry in Nuclei
Ginocchio, Joseph N
2014-01-01
Pseudospin symmetry has been useful in understanding atomic nuclei. We review the arguments that this symmetry is a relativistic symmetry. The condition for this symmetry is that the sum of the vector and scalar potentials in the Dirac Hamiltonian is a constant. We give the generators of pseudospin symmetry. We review some of the predictions that follow from this insight into the relativistic origins of pseudospin symmetry. Since in nuclei the sum of the scalar and vector potentials is not zero but is small, we discuss preliminary investigations into the conditions on the potentials to produce partial dynamic pseudospin symmetry. Finally we show that approximate pseudospin symmetry in nuclei predicts approximate spin symmetry in anti-nucleon scattering from nuclei.
Physics with loosely bound nuclei
Indian Academy of Sciences (India)
Chhanda Samanta
2001-08-01
The essential aspect of contemporary physics is to understand properties of nucleonic matter that constitutes the world around us. Over the years research in nuclear physics has provided strong guidance in understanding the basic principles of nuclear interactions. But, the scenario of nuclear physics changed drastically as the new generation of accelerators started providing more and more rare isotopes, which are away from the line of stability. These weakly bound nuclei are found to exhibit new forms of nuclear matter and unprecedented exotic behaviour. The low breakup thresholds of these rare nuclei are posing new challenges to both theory and experiments. Fortunately, nature has provided a few loosely bound stable nuclei that have been studied thoroughly for decades. Attempts are being made to ﬁnd a consistent picture for the unstable nuclei starting from their stable counterparts. Some signiﬁcant differences in the structure and reaction mechanisms are found.
Nagao, Makoto
1990-01-01
Knowledge and Inference discusses an important problem for software systems: How do we treat knowledge and ideas on a computer and how do we use inference to solve problems on a computer? The book talks about the problems of knowledge and inference for the purpose of merging artificial intelligence and library science. The book begins by clarifying the concept of """"knowledge"""" from many points of view, followed by a chapter on the current state of library science and the place of artificial intelligence in library science. Subsequent chapters cover central topics in the artificial intellig
Division of Free Nuclei in Rice Endosperm and Its Influencing Factors
Institute of Scientific and Technical Information of China (English)
LIU Man-xi; WANG Zhong; WU Xiao-mei; CHEN Yi-fang; GU Yun-jie
2009-01-01
The division process of endosperm in rice and its influencing factors were investigated. Total dissection, resin embedding and sectioning under light and transmission electron microscopes were used to observe the division patterns of free nuclei and cytological characters of an endosperm. The various division patterns of free nuclei in rice endosperm included mitosis, amitosis, and the mitosis to amitosis change without an interphase. The division velocity of free nuclei in rice endosperm varied with the internucleus distance. Comparing to a cluster, the division velocity increased when the free nuclei were separated from each other. Moderately higher temperatures also enhanced the proliferation and shortened the division cycle of free nuclei in rice endosperm. To a certain extent, nitrogenous fertilizer applied at the booting stage together with a moderate drought treatment accelerated the division of free nuclei as well.
Charge-changing interactions probing point-proton radii of nuclei
Directory of Open Access Journals (Sweden)
Yamaki S.
2014-03-01
Full Text Available The question of whether charge-changing interactions can be used to probe point-proton radii of nuclei remains unanswered. Charge-changing cross sections, σcc, were systematically investigated using stable and unstable nuclear beams of intermediateenergy. The ratios of the experimental σcc values to the calculated ones obtained from a phenomenological Glauber-type model analysis are found to be nearly constant in a broad range of Z/N for light neutron-rich nuclei. This enables the determination of density distributions, i.e., the radii of protons tightly bound in nuclei. To test the applicability of the present method to all nuclei in the nuclear chart, extensive measurements were performed for medium-mass nuclei ranging from Z = 18 to 32. The present study suggests the potential capability of a new experimental approach for exploring exotic nuclei.
Probability and Statistical Inference
Prosper, Harrison B.
2006-01-01
These lectures introduce key concepts in probability and statistical inference at a level suitable for graduate students in particle physics. Our goal is to paint as vivid a picture as possible of the concepts covered.
Origin of Interplanetary Dust through Optical Properties of Zodiacal Light
Yang, Hongu
2015-01-01
This study investigates the origin of interplanetary dust particles (IDPs) through the optical properties, albedo and spectral gradient, of zodiacal light. The optical properties were compared with those of potential parent bodies in the solar system, which include D-type (as analogue of cometary nuclei), C-type, S-type, X-type, and B-type asteroids. We applied Bayesian inference on the mixture model made from the distribution of these sources, and found that >90% of the interplanetary dust particles originate from comets (or its spectral analogues, D-type asteroids). Although some classes of asteroids (C-type and X-type) may make a moderate contribution, ordinary chondrite-like particles from S-type asteroids occupy a negligible fraction of the interplanetary dust cloud complex. The overall optical properties of the zodiacal light were similar to those of chondritic porous IDPs, supporting the dominance of cometary particles in zodiacal cloud.
Introductory statistical inference
Mukhopadhyay, Nitis
2014-01-01
This gracefully organized text reveals the rigorous theory of probability and statistical inference in the style of a tutorial, using worked examples, exercises, figures, tables, and computer simulations to develop and illustrate concepts. Drills and boxed summaries emphasize and reinforce important ideas and special techniques.Beginning with a review of the basic concepts and methods in probability theory, moments, and moment generating functions, the author moves to more intricate topics. Introductory Statistical Inference studies multivariate random variables, exponential families of dist
From heavy nuclei to super-heavy nuclei
Theisen, C
2003-01-01
The existence of super-heavy nuclei has been predicted nearly fifty years ago. Due to the strong coulomb repulsion, the stabilisation of these nuclei is possible only through shell effects. The reasons for this fragile stability, as well as the theoretical predictions concerning the position of the island of stability are presented in the first part of this lecture. In the second part, experiments and experimental techniques which have been used to synthesize or search for super-heavy elements are described. Spectroscopic studies performed in very heavy elements are presented in the following section. We close this lecture with techniques that are currently being developed in order to reach the superheavy island and to study the structure of very-heavy nuclei.
Exotic decay of hot rotating nuclei near proton drip line
Ray, J.; Datta Pramanik, U.; Bhowmik, R. K.; Ray, I.; Rahaman, A.; Chakraborty, A.; Chakraborty, S.; Garg, R.; Goyal, S.; Ganguly, S.; Kumar, S.; Mandal, S.; Mukherjee, B.; Mukherjee, P.; Muralithar, S.; Negi, D.; Saxena, M.; Selvakumar, K.; Singh, P.; Singh, A. K.; Singh, R. P.
2014-03-01
Hot and rotating exotic 124Ce nucleus near proton drip line has been populated through fusion evaporation reaction of 32S and 92Mo. This exotic nucleus was de-excited by evaporating p, n, α and/or light nuclei etc and several exotic nuclei have been populated. The experimentally obtained relative population of those exotic nuclei have been compared with the statistical model calculation. Agreement between experimental and statistical model calculation have been observed for most of the evaporation channels. Huge enhancement in comparison to statistical model calculation have been observed fora few channels related to multiple proton evaporation which could not be explained by using default and modified input parameters in statistical calculation.
Coupled cluster calculations of neutron-rich nuclei
Hagen, Gaute
2016-09-01
In this talk I will present recent highlights from ab initio computations of atomic nuclei using coupled-cluster methods with state-of-the-art interactions from chiral effective field theory (EFT). The recent progress in computing nuclei from scratch is based on new optimizations of interactions from chiral EFT, and ab initio methods with a polynomial computational cost together with available super computing resources. The physics advancements I will discuss include: (i) accurate nuclear binding energies and radii of light and medium-mass nuclei, (ii) the neutron distribution and electric dipole polarizability of the nucleus 48Ca, (iii) and the structure of the rare nucleus 78Ni from first principles. All these quantities are currently targeted by precision measurements worldwide.
Nuclei at extreme conditions. A relativistic study
Energy Technology Data Exchange (ETDEWEB)
Afanasjev, Anatoli [Mississippi State Univ., Mississippi State, MS (United States)
2014-11-14
The major goals of the current project were further development of covariant density functional theory (CDFT), better understanding of its features, its application to different nuclear structure and nuclear astrophysics phenomena and training of graduate and undergraduate students. The investigations have proceeded in a number of directions which are discussed in detail in the part “Accomplishments” of this report. We have studied the role of isovector and isoscalar proton-neutron pairings in rotating nuclei; based on available experimental data it was concluded that there are no evidences for the existence of isoscalar proton-neutron pairing. Generalized theoretical approach has been developed for pycnonuclear reaction rates in the crust of neutron stars and interior of white dwarfs. Using this approach, extensive database for considerable number of pycnonuclear reactions involving stable and neutron-rich light nuclei has been created; it can be used in future for the study of various nuclear burning phenomena in different environments. Time-odd mean fields and their manifestations in terminating states, non-rotating and rotating nuclei have been studied in the framework of covariant density functional theory. Contrary to non-relativistic density functional theories these fields, which are important for a proper description of nuclear systems with broken time-reversal symmetry, are uniquely defined in the CDFT framework. Hyperdeformed nuclear shapes (with semi-axis ratio 2.5:1 and larger) have been studied in the Z = 40-58 part of nuclear chart. We strongly believe that such shapes could be studied experimentally in the future with full scale GRETA detector.
Photodissociation of neutron deficient nuclei
Energy Technology Data Exchange (ETDEWEB)
Sonnabend, K.; Babilon, M.; Hasper, J.; Mueller, S.; Zarza, M.; Zilges, A. [TU Darmstadt, Institut fuer Kernphysik, Darmstadt (Germany)
2006-03-15
The knowledge of the cross sections for photodissociation reactions like e.g. ({gamma}, n) of neutron deficient nuclei is of crucial interest for network calculations predicting the abundances of the so-called p nuclei. However, only single cross sections have been measured up to now, i.e., one has to rely nearly fully on theoretical predictions. While the cross sections of stable isotopes are accessible by experiments using real photons, the bulk of the involved reactions starts from unstable nuclei. Coulomb dissociation (CD) experiments in inverse kinematics might be a key to expand the experimental database for p-process network calculations. The approach to test the accuracy of the CD method is explained. (orig.)
A relativistic symmetry in nuclei
Energy Technology Data Exchange (ETDEWEB)
Ginocchio, J N [MS B283, Theoretical Division, Los Alamos National Laboratory Los Alamos, New Mexico 87545 (Mexico)
2007-11-15
We review some of the empirical and theoretical evidence supporting pseudospin symmetry in nuclei as a relativistic symmetry. We review the case that the eigenfunctions of realistic relativistic nuclear mean fields approximately conserve pseudospin symmetry in nuclei. We discuss the implications of pseudospin symmetry for magnetic dipole transitions and Gamow-Teller transitions between states in pseudospin doublets. We explore a more fundamental rationale for pseudospin symmetry in terms of quantum chromodynamics (QCD), the basic theory of the strong interactions. We show that pseudospin symmetry in nuclei implies spin symmetry for an anti-nucleon in a nuclear environment. We also discuss the future and what role pseudospin symmetry may be expected to play in an effective field theory of nucleons.
Spontaneous fission of superheavy nuclei
Indian Academy of Sciences (India)
R A Gherghescu; D N Poenaru
2015-09-01
The macroscopic–microscopic method is extended to calculate the deformation energy and penetrability for binary nuclear configurations typical for fission processes. The deformed two-centre shell model is used to obtain single-particle energy levels for the transition region of two partially overlapped daughter and emitted fragment nuclei. The macroscopic part is obtained using the Yukawa-plus-exponential potential. The microscopic shell and pairing corrections are obtained using the Strutinsky and BCS approaches and the cranking formulae yield the inertia tensor. Finally, the WKB method is used to calculate penetrabilities and spontaneous fission half-lives. Calculations are performed for the decay of 282,292120 nuclei.
Octupole shapes in heavy nuclei
Energy Technology Data Exchange (ETDEWEB)
Ahmad, I.
1994-08-01
Theoretical calculations and measurements show the presence of strong octupole correlations in thecyround states and low-lying states of odd-mass and odd-odd nuclei in the RaPa region. Evidence for octupole correlations is provided by the observation of parity doublets and reductions in M1 matrix elements, decoupling parameters, and Coriolis matrix elements Involving high-j states. Enhancement of E1 transition rates has also been observed for some of the octupole deformed nuclei. The most convincing argument for octupole deformation is provided by the similarities of the reduced alpha decay rates to the two members of parity doublets.
International Symposium on Exotic Nuclei
Sobolev, Yu G; EXON-2014
2015-01-01
The production and the properties of nuclei in extreme conditions, such as high isospin, temperature, angular momenta, large deformations etc., have become the subject of detailed investigations in all scientific centers. The main topics discussed at the Symposium were: Synthesis and Properties of Exotic Nuclei; Superheavy Elements; Rare Processes, Nuclear Reactions, Fission and Decays; Experimental Facilities and Scientific Projects. This book provides a comprehensive overview of the newest results of the investigations in the main scientific centers such as GSI (Darmstadt, Germany), GANIL (Caen, France), RIKEN (Wako-shi, Japan), MSU (Michigan, USA), and JINR (Dubna, Russia).
Accardi, Alberto
2016-01-01
I review recent progress in the extraction of unpolarized parton distributions in the proton and in nuclei from a unified point of view that highlights how the interplay between high energy particle physics and lower energy nuclear physics can be of mutual benefit to either field. Areas of overlap range from the search for physics beyond the standard model at the LHC, to the study of the non perturbative structure of nucleons and the emergence of nuclei from quark and gluon degrees of freedom, to the interaction of colored probes in a cold nuclear medium.
Energy Technology Data Exchange (ETDEWEB)
Hanson, K.M.; Cunningham, G.S.
1996-04-01
The authors are developing a computer application, called the Bayes Inference Engine, to provide the means to make inferences about models of physical reality within a Bayesian framework. The construction of complex nonlinear models is achieved by a fully object-oriented design. The models are represented by a data-flow diagram that may be manipulated by the analyst through a graphical programming environment. Maximum a posteriori solutions are achieved using a general, gradient-based optimization algorithm. The application incorporates a new technique of estimating and visualizing the uncertainties in specific aspects of the model.
Knuth, Kevin H
2010-01-01
We present a foundation for inference that unites and significantly extends the approaches of Kolmogorov and Cox. Our approach is based on quantifying finite lattices of logical statements in a way that satisfies general lattice symmetries. With other applications in mind, our derivations assume minimal symmetries, relying on neither complementarity nor continuity or differentiability. Each relevant symmetry corresponds to an axiom of quantification, and these axioms are used to derive a unique set of rules governing quantification of the lattice. These rules form the familiar probability calculus. We also derive a unique quantification of divergence and information. Taken together these results form a simple and clear foundation for the quantification of inference.
Making Type Inference Practical
DEFF Research Database (Denmark)
Schwartzbach, Michael Ignatieff; Oxhøj, Nicholas; Palsberg, Jens
1992-01-01
We present the implementation of a type inference algorithm for untyped object-oriented programs with inheritance, assignments, and late binding. The algorithm significantly improves our previous one, presented at OOPSLA'91, since it can handle collection classes, such as List, in a useful way. Abo....... Experiments indicate that the implementation type checks as much as 100 lines pr. second. This results in a mature product, on which a number of tools can be based, for example a safety tool, an image compression tool, a code optimization tool, and an annotation tool. This may make type inference for object...
Production of Polarized Vector Mesons off Nuclei
Kopeliovich, B Z; Schmidt, I; Schmidt, Ivan
2007-01-01
Using the light-cone QCD dipole formalism we investigate manifestations of color transparency (CT) and coherence length (CL) effects in electroproduction of longitudinally (L) and transversally (T) polarized vector mesons. Motivated by forthcoming data from the HERMES experiment we predict both the A and Q^2 dependence of the L/T- ratios, for rho^0 mesons produced coherently and incoherently off nuclei. For an incoherent reaction the CT and CL effects add up and result in a monotonic A dependence of the L/T-ratio at different values of Q^2. On the contrary, for a coherent process the contraction of the CL with Q^2 causes an effect opposite to that of CT and we expect quite a nontrivial A dependence, especially at Q^2 >> m_V^2.
Partial Dynamical Symmetries in Nuclei
Leviatan, A
2000-01-01
Partial dynamical symmetries (PDS) are shown to be relevant to the interpretation of the $K=0_2$ band and to the occurrence of F-spin multiplets of ground and scissors bands in deformed nuclei. Hamiltonians with bosonic and fermionic PDS are presented.
Multiphonon giant resonances in nuclei
Energy Technology Data Exchange (ETDEWEB)
Aumann, T. [Mainz Univ. (Germany). Inst. fuer Kernchemie; Bortignon, P.F. [Milan Univ. (Italy). Dipt. di Fisica]|[Istituto Nazionale di Fisica Nucleare, Milan (Italy); Emling, H. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)
1998-07-01
We review the present knowledge of multiphonon giant resonances in nuclei. Theoretical concepts approaching the intrinsic structure and excitation mechanisms of multi-phonon states are discussed. The available experimental results are summarized, including a brief description of applied techniques. This review emphasizes electromagnetic excitations of double dipole resonances. Open questions and possible routes toward a solution are addressed. (orig.)
Fission dynamics of hot nuclei
Indian Academy of Sciences (India)
Santanu Pal; Jhilam Sadhukhan
2014-04-01
Experimental evidence accumulated during the last two decades indicates that the fission of excited heavy nuclei involves a dissipative dynamical process. We shall briefly review the relevant dynamical model, namely the Langevin equations for fission. Statistical model predictions using the Kramers’ fission width will also be discussed.
Low energy + scattering on = nuclei
Indian Academy of Sciences (India)
Swapan Das; Arun K Jain
2003-11-01
The data for the total cross-section of + scattering on various nuclei have been analysed in the Glauber multiple scattering theory. Energy-dependent +-nucleus optical potential is generated using the forward +-nucleon scattering amplitude and the nuclear density distribution. Along with this, the calculated total +-nucleus cross-sections using the effective +-nucleon cross-section inside the nucleus are also presented.
Watson, Jane
2007-01-01
Inference, or decision making, is seen in curriculum documents as the final step in a statistical investigation. For a formal statistical enquiry this may be associated with sophisticated tests involving probability distributions. For young students without the mathematical background to perform such tests, it is still possible to draw informal…
Photon-axion mixing within the jets of active galactic nuclei and prospects for detection
Energy Technology Data Exchange (ETDEWEB)
Harris, J.; Chadwick, P.M., E-mail: j.d.harris@durham.ac.uk, E-mail: p.m.chadwick@durham.ac.uk [Durham University, Department of Physics, South Road, Durham DH1 3LE (United Kingdom)
2014-10-01
Very high energy γ-ray observations of distant active galactic nuclei (AGN) generally result in higher fluxes and harder spectra than expected, resulting in some tension with the level of the extragalactic background light (EBL). If hypothetical axions or axion-like particles (ALPs) were to exist, this tension could be relieved since the oscillation of photons to ALPs would mitigate the effects of EBL absorption and lead to softer inferred intrinsic AGN spectra. In this paper we consider the effect of photon-ALP mixing on observed spectra, including the photon-ALP mixing that would occur within AGN jets. We then simulate observations of three AGN with the Cherenkov Telescope Array (CTA), a next generation γ-ray telescope, to determine its prospects for detecting the signatures of photon-ALP mixing on the spectra. We conclude that prospects for CTA detecting these signatures or else setting limits on the ALP parameter space are quite promising. We find that prospects are improved if photon-ALP mixing within the jet is properly considered and that the best target for observations is PKS 2155-304.
Fragmentation of relativistic oxygen nuclei in interactions with a proton
Glagolev, V V; Lipin, V D; Lutpullaev, S L; Olimov, K K; Yuldashev, A A; Yuldashev, B S; Olimov, Kh.K.
2001-01-01
The data on investigation of inelastic interactions of 16O nuclei with a proton at 3.25 A GeV/c momentum by the bubble chamber method are presented. The separate characteristics as fragments isotopic composition and as topo-logical cross sections of fragmentation channels are given. The processes of light fragments formation and breakup of 16O nucleus on multicharge fragments have been investigated. The comparison of experimental data with the calculations by statistical multifragmentation model was conducted.
Investigation of Properties of Exotic Nuclei in Non-relativistic and Relativistic Models
Institute of Scientific and Technical Information of China (English)
2001-01-01
Properties of exotic nuclei are described by non-relativistic and relativistic models. The relativistic mean field theory predicts one proton halo in 26,27,28P and two proton halos in 27,28,29S, recently, one proton halo in 26,27,28P has been found experimentally in MSU lab. The relativistic Hartree-Fock theory has been used to investigate the contribution of Fock term and isovector mesons to the properties of exotic nuclei. It turns out that the influence of the Fock term and isovector mesons on the properties of neutron extremely rich nuclei is very different from that of near stable nuclei. Meanwhile, the deformed Hartree-Fock-Bogoliubov theory has been employed to describe the ground state properties of the isotopes for some light nuclei.
Reactions with fast radioactive beams of neutron-rich nuclei
Energy Technology Data Exchange (ETDEWEB)
Aumann, T. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)
2005-11-01
The neutron dripline has presently been reached only for the lightest nuclei up to the element oxygen. In this region of light neutron-rich nuclei, scattering experiments are feasible even for dripline nuclei by utilizing high-energy secondary beams produced by fragmentation. In the present article, reactions of high-energy radioactive beams will be exemplified using recent experimental results mainly derived from measurements of breakup reactions performed at the LAND and FRS facilities at GSI and at the S800 spectrometer at the NSCL. Nuclear and electromagnetically induced reactions allow probing different aspects of nuclear structure at the limits of stability related to the neutron-proton asymmetry and the weak binding close to the dripline. Properties of the valence-neutron wave functions are studied in the one-neutron knockout reaction, revealing the changes of shell structure when going from the beta-stability line to more asymmetric loosely bound neutron-rich systems. The vanishing of the N=8 shell gap for neutron-rich systems like {sup 11}Li and {sup 12}Be, or the new closed N=14, 16 shells for the oxygen isotopes are examples. The continuum of weakly bound nuclei and halo states can be studied by inelastic scattering. The dipole response, for instance, is found to change dramatically when going away from the valley of stability. A redistribution of the dipole strength towards lower excitation energies is observed for neutron-rich nuclei, which partly might be due to a new collective excitation mode related to the neutron-proton asymmetry. Halo nuclei in particular show strong dipole transitions to the continuum at the threshold, being directly related to the ground-state properties of the projectile. Finally, an outlook on future experimental prospects is given. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Lapoux, V
2005-09-15
Information on the structure, spectroscopy and target interaction potentials of exotic nuclei can be inferred by interpreting measured data from direct reactions on proton such as elastic or inelastic scattering of proton (p,p') or one-nucleon transfer reaction (p,d). A series of experimental results has been obtained at the GANIL facilities on the setting composed of the MUST telescope array used for the detection of light charged-particles and of CATS beam detectors. This setting aims at measuring reactions on light proton or deuteron targets through reverse kinematics. Particularly, results on C{sup 10}, C{sup 11} and on direct reactions with the He{sup 8} beam of Spiral are presented. The first chapter is dedicated to the description of the most important theories concerning the nucleus. The experimental tools used to probe the nucleus are reported in the second chapter. The third and fourth chapters present the framework that has allowed us to analyse results from (p,p') and (p,d) reactions on weakly bound exotic nuclei. The last chapter is dedicated to the description of future experimental programs. (A.C.)
Directory of Open Access Journals (Sweden)
Wu C.Y.
2012-02-01
Full Text Available Spectra of γ rays following neutron capture at isolated resonances of 6 stable Gd isotopes were measured with highly segmented BaF2 detector DANCE at the Los Alamos LANSCE spallation neutron source. The main emphasis was put on studying the γ-cascade decay of neutron resonances to get unique information on photon strength. An analysis of the accumulated γ-ray spectra within the extreme statistical model leads to an inescapable conclusion that scissors mode resonances are built not only on the ground-state, but also on excited levels in all product nuclei studied. The results on summed B(M1↑ strength and energy of the scissors mode are compared with systematics of scissors mode parameters for the ground-state transitions deduced from nuclear resonance fluorescence measurements. A specific feature of our experiments is the investigation of scissors mode of odd nuclei, for which the nuclear resonance fluorescence provides only limited information.
Kroll, J.; Baramsai, B.; Becker, J. A.; Bečvář, F.; Bredeweg, T. A.; Couture, A.; Chyzh, A.; Dashdorj, D.; Haight, R. C.; Jandel, M.; Krtička, M.; Mitchell, G. E.; O'Donnell, J. M.; Parker, W.; Rundberg, R. S.; Ullmann, J. L.; Vieira, G. J.; Walker, C. L.; Wilhelmy, J. B.; Wouters, J. M.; Wu, C. Y.
2012-02-01
Spectra of γ rays following neutron capture at isolated resonances of 6 stable Gd isotopes were measured with highly segmented BaF2 detector DANCE at the Los Alamos LANSCE spallation neutron source. The main emphasis was put on studying the γ-cascade decay of neutron resonances to get unique information on photon strength. An analysis of the accumulated γ-ray spectra within the extreme statistical model leads to an inescapable conclusion that scissors mode resonances are built not only on the ground-state, but also on excited levels in all product nuclei studied. The results on summed B(M1)↑ strength and energy of the scissors mode are compared with systematics of scissors mode parameters for the ground-state transitions deduced from nuclear resonance fluorescence measurements. A specific feature of our experiments is the investigation of scissors mode of odd nuclei, for which the nuclear resonance fluorescence provides only limited information.
Causal inference in econometrics
Kreinovich, Vladik; Sriboonchitta, Songsak
2016-01-01
This book is devoted to the analysis of causal inference which is one of the most difficult tasks in data analysis: when two phenomena are observed to be related, it is often difficult to decide whether one of them causally influences the other one, or whether these two phenomena have a common cause. This analysis is the main focus of this volume. To get a good understanding of the causal inference, it is important to have models of economic phenomena which are as accurate as possible. Because of this need, this volume also contains papers that use non-traditional economic models, such as fuzzy models and models obtained by using neural networks and data mining techniques. It also contains papers that apply different econometric models to analyze real-life economic dependencies.
Directory of Open Access Journals (Sweden)
João Paulo Monteiro
2001-12-01
Full Text Available Russell's The Problems of Philosophy tries to establish a new theory of induction, at the same time that Hume is there accused of an irrational/ scepticism about induction". But a careful analysis of the theory of knowledge explicitly acknowledged by Hume reveals that, contrary to the standard interpretation in the XXth century, possibly influenced by Russell, Hume deals exclusively with causal inference (which he never classifies as "causal induction", although now we are entitled to do so, never with inductive inference in general, mainly generalizations about sensible qualities of objects ( whether, e.g., "all crows are black" or not is not among Hume's concerns. Russell's theories are thus only false alternatives to Hume's, in (1912 or in his (1948.
Stochastic processes inference theory
Rao, Malempati M
2014-01-01
This is the revised and enlarged 2nd edition of the authors’ original text, which was intended to be a modest complement to Grenander's fundamental memoir on stochastic processes and related inference theory. The present volume gives a substantial account of regression analysis, both for stochastic processes and measures, and includes recent material on Ridge regression with some unexpected applications, for example in econometrics. The first three chapters can be used for a quarter or semester graduate course on inference on stochastic processes. The remaining chapters provide more advanced material on stochastic analysis suitable for graduate seminars and discussions, leading to dissertation or research work. In general, the book will be of interest to researchers in probability theory, mathematical statistics and electrical and information theory.
Proton scattering from unstable nuclei
Indian Academy of Sciences (India)
Y Blumenfeld; E Khan; F Maréchal; T Suomijärvi
2001-08-01
Recent improvements in the intensities and optical qualities of radioactive beams have made possible the study of elastic and inelastic proton scattering on unstable nuclei. The design and performances of an innovative silicon strip detector array devoted to such experiments are described. The quality of the data obtained are illustrated with recent results obtained at the GANIL facility for unstable oxygen, sulfur and argon isotopes. Methods to analyse the data using phenomenological and microscopic optical model potentials are discussed.
Strange neutral currents in nuclei
Ressell, M T; Aufderheide, M B; Bloom, S D; Resler, D A
1995-01-01
We examine the effects on the nuclear neutral current Gamow-Teller (GT) strength of a finite contribution from a polarized strange quark sea. We perform nuclear shell model calculations of the neutral current GT strength for a number of nuclei likely to be present during stellar core collapse. We compare the GT strength when a finite strange quark contribution is included to the strength without such a contribution. As an example, the process of neutral current nuclear de-excitation via \
Weak pion production from nuclei
Indian Academy of Sciences (India)
S K Singh; M Sajjad Athar; Shakeb Ahmad
2006-04-01
The charged current pion production induced by neutrinos in 12C, 16O and 56Fe nuclei has been studied. The calculations have been done for the coherent as well as the incoherent processes assuming dominance and takes into account the effect of Pauli blocking, Fermi motion and the renormalization of in the nuclear medium. The pion absorption effects have also been taken into account.
Triaxial rotation in atomic nuclei
Institute of Scientific and Technical Information of China (English)
CHEN Yong-Shou; GAO Zao-Chun
2009-01-01
The Projected Shell Model has been developed to include the spontaneously broken axial symmetry so that the rapidly rotating triaxial nuclei can be described microscopically. The theory provides an useful tool to gain an insight into how a triaxial nucleus rotates, a fundamental question in nuclear structure. We shall address some current interests that are strongly associated with the triaxial rotation. A feasible method to explore the problem has been suggested.
Double pion photoproduction in nuclei
Vicente-Vacas, M J; Gómez-Tejedor, J A; Vicente-Vacas, M J; Oset, E; Gómez Tejedor, J A
1994-01-01
Abstract: The inclusive A(gamma,pi+ pi-)X reaction is studied theoretically. A sizeable enhancement of the cross section is found, in comparison with the scaling of the deuteron cross section (sigma_deuteron * A/2). This enhancement is due to the modifications in the nuclear medium of the gamma N ----> pi pi N amplitude and the pion dispersion relation. The enhancement is found to be bigger than the one already observed in the (pi,pi pi) reaction in nuclei.
Energy Technology Data Exchange (ETDEWEB)
KENNETH M. HANSON; JANE M. BOOKER
2000-09-08
The authors an uncertainty analysis of data taken using the Rossi technique, in which the horizontal oscilloscope sweep is driven sinusoidally in time ,while the vertical axis follows the signal amplitude. The analysis is done within a Bayesian framework. Complete inferences are obtained by tilting the Markov chain Monte Carlo technique, which produces random samples from the posterior probability distribution expressed in terms of the parameters.
Inferring Microbial Fitness Landscapes
2016-02-25
experiments on evolving microbial populations. Although these experiments have produced examples of remarkable phenomena – e.g. the emergence of mutator...what specific mutations, avian influenza viruses will adapt to novel human hosts; or how readily infectious bacteria will escape antibiotics or the...infer from data the determinants of microbial evolution with sufficient resolution that we can quantify 1. REPORT DATE (DD-MM-YYYY) 4. TITLE AND
Continuous Integrated Invariant Inference Project
National Aeronautics and Space Administration — The proposed project will develop a new technique for invariant inference and embed this and other current invariant inference and checking techniques in an...
Probabilistic Inferences in Bayesian Networks
Ding, Jianguo
2010-01-01
This chapter summarizes the popular inferences methods in Bayesian networks. The results demonstrates that the evidence can propagated across the Bayesian networks by any links, whatever it is forward or backward or intercausal style. The belief updating of Bayesian networks can be obtained by various available inference techniques. Theoretically, exact inferences in Bayesian networks is feasible and manageable. However, the computing and inference is NP-hard. That means, in applications, in ...
A Statistical Approach to Describe Highly Excited Heavy and Superheavy Nuclei
Chen, Peng-Hui; Li, Jun-Qing; Zhang, Hong-Fei
2016-01-01
A statistical approach based on the Weisskopf evaporation theory has been developed to describe the de-excitation process of highly excited heavy and superheavy nuclei, in particular for the proton-rich nuclei. The excited nucleus is cooled by evaporating $\\gamma$-ray, light particles (neutrons, protons, $\\alpha$ etc) in competition with the binary fission, in which the structure effects (shell correction, fission barrier, particle separation energy) contribute to the processes. The formation of residual nuclei is evaluated via sequential emission of possible particles above the separation energies. The available data of fusion-evaporation excitation functions in the $^{28}$Si+$^{198}$Pt reaction can be reproduced nicely well within the approach.
Nuclei Measurements with the Alpha Magnetic Spectrometer on the International Space Station
Heil, Melanie
2017-03-01
The exact behavior of nuclei fluxes in cosmic rays and how they relate to each other is important for understanding the production, acceleration and propagation mechanisms of charged cosmic rays. Precise measurements with the Alpha Magnetic Spectrometer on the International Space Station of light nuclei fluxes and their ratios in primary cosmic rays with rigidities from GV to TV are presented. The high statistics of the measurements require detailed studies and in depth understanding of associated systematic uncertainties.
Nuclei Measurements with the Alpha Magnetic Spectrometer on the International Space Station
Directory of Open Access Journals (Sweden)
Heil Melanie
2017-01-01
Full Text Available The exact behavior of nuclei fluxes in cosmic rays and how they relate to each other is important for understanding the production, acceleration and propagation mechanisms of charged cosmic rays. Precise measurements with the Alpha Magnetic Spectrometer on the International Space Station of light nuclei fluxes and their ratios in primary cosmic rays with rigidities from GV to TV are presented. The high statistics of the measurements require detailed studies and in depth understanding of associated systematic uncertainties.
Multimodel inference and adaptive management
Rehme, S.E.; Powell, L.A.; Allen, C.R.
2011-01-01
Ecology is an inherently complex science coping with correlated variables, nonlinear interactions and multiple scales of pattern and process, making it difficult for experiments to result in clear, strong inference. Natural resource managers, policy makers, and stakeholders rely on science to provide timely and accurate management recommendations. However, the time necessary to untangle the complexities of interactions within ecosystems is often far greater than the time available to make management decisions. One method of coping with this problem is multimodel inference. Multimodel inference assesses uncertainty by calculating likelihoods among multiple competing hypotheses, but multimodel inference results are often equivocal. Despite this, there may be pressure for ecologists to provide management recommendations regardless of the strength of their study’s inference. We reviewed papers in the Journal of Wildlife Management (JWM) and the journal Conservation Biology (CB) to quantify the prevalence of multimodel inference approaches, the resulting inference (weak versus strong), and how authors dealt with the uncertainty. Thirty-eight percent and 14%, respectively, of articles in the JWM and CB used multimodel inference approaches. Strong inference was rarely observed, with only 7% of JWM and 20% of CB articles resulting in strong inference. We found the majority of weak inference papers in both journals (59%) gave specific management recommendations. Model selection uncertainty was ignored in most recommendations for management. We suggest that adaptive management is an ideal method to resolve uncertainty when research results in weak inference.
Neutron and Alpha Structure in Neutron Deficient Nuclei in Astrophysics
Institute of Scientific and Technical Information of China (English)
S. Kubono; T. Hashimoto; Y. Wakabayashi; N. Iwasa; S. Kato; T. Komatsubara; D. N. Binh; L. H. Khiem; N. N. Duy; T. Kawabata; C. Spitaleri; 何建军; G. G. Rapisarda; M. La Cognata; L. Lamia; R. G. Pizzone; S. Romano; A. Coc; N. de Sereville; F. Hammache; G. Kiss; S. Bishop; H. Yamaguchi; D. M. Kahl; S. Hayakawa; T. Teranishi; S. Cheribini; M. Gulino; Y. K. Kwon
2016-01-01
The paper includes discussions on the important role of neutron and alpha configurations in proton-rich nuclei in nuclear astrophysics in terms of nucleosynthesis under extremely high-temperature hydrogenburning conditions. The νp-process, which is supposed to take place at the very early epoch of type II supernovae, has considerable neutrons and alphas together with protons. The alpha-induced reactions on proton-rich unstable nuclei in the light mass regions is expected to play a crucial role, but very few of them were investigated well yet because of the experimental diﬃculties. Specifically, I report our recent experimental effort for the breakout process from the pp-chain region, 7Be(α,γ)11C(α,p)14N under the νp-process. The neutron-induced reactions on proton-rich nuclei, which is even more a challenging subject, were investigated previously for very few nuclei. One possible experimental method is the Trojan Horse Method (THM). We successfully have applied THM to the 18F(n,α)14N reaction study with an unstable beam of 18F.
Toddlers infer higher-order relational principles in causal learning.
Walker, Caren M; Gopnik, Alison
2014-01-01
Children make inductive inferences about the causal properties of individual objects from a very young age. When can they infer higher-order relational properties? In three experiments, we examined 18- to 30-month-olds' relational inferences in a causal task. Results suggest that at this age, children are able to infer a higher-order relational causal principle from just a few observations and use this inference to guide their own subsequent actions and bring about a novel causal outcome. Moreover, the children passed a revised version of the relational match-to-sample task that has proven very difficult for nonhuman primates. The findings are considered in light of their implications for understanding the nature of relational and causal reasoning, and their evolutionary origins.
Energy Technology Data Exchange (ETDEWEB)
Azuelos, G.; Gorringe, T.P.; Henderson, R.; Macdonald, J.A.; Poutissou, J.M. (TRIUMPH, Vancouver, BC (CA)); Azuelos, G.; Depommier, P.; Poutissou, R. (Montreal Univ., PQ (CA)); Ahmad, S.; Burnham, A.; Hasinoff, M.D.; Larabee, A.J.; Waltham, C.E.; Wright, D.H. (British Columbia Univ., Vancouver, BC (CA)); Armstrong, D.S.; Blecher, M.; Serna-Angel, A. (Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (US)); Bertl, W. (Paul Scherrer Inst. (PSI), Wuerenlingen (CH)); Chen, C.Q.; Zhang, N.S. (Academia Sinica, Beijing, BJ (CN). Inst. of High Energy Physics); Egidy, T. von (Technische Univ. Muenchen (DE)); McDonald, S.C.; Taylor, G.N. (Melbourne Univ., Parkville (AU)); Robertson, B.C. (Queen' s Univ., Belfast, Northern Ireland (UK))
1990-06-01
A brief review is made of the study of gp, the induced pseudoscalar coupling constant, in radiative muon capture on light nuclei, and of motivations for a measurement on hydrogen, with particular emphasis on recent and ongoing experiments at TRIUMF.
The Role of Nuclei-Nuclei Interactions in the Production of Gamma-ray Lines in Solar Flares
Institute of Scientific and Technical Information of China (English)
Boris M. Kuzhevskij; Wei-Qun Gan; Leonty I. Miroshnichenko
2005-01-01
Dramatic extensions of experimental possibilities (spacecraft RHESSI,CORONAS-F and others) in solar gamma-ray astronomy call for urgent, detailed theoretical consideration of a set of physical problems of solar activity and solarterrestrial relationships that earlier may have only been outlined. Here we undertake a theoretical analysis of issues related to the production of gamma-radiation in the processes of interactions of energetic (accelerated) heavy and middle nuclei with the nuclei of the solar atmosphere (the so-called i-j interactions). We also make an estimate of the contribution of these interactions to the formation of nuclear and isotopic abundances of the solar atmosphere in the range of light and rare elements. The analysis is carried out for solar flares in the wide range of their intensities. We compare our theoretical estimates with RHESSI observations for the flare of 2002 July 23. It was shown that the 24Mg gamma-ray emission in this event was produced by the newly generated Mg nuclei. With a high probability,the gamma-ray line emission of 28Si nuclei from this flare was generated by the same processes.
Tactile length contraction as Bayesian inference.
Tong, Jonathan; Ngo, Vy; Goldreich, Daniel
2016-08-01
To perceive, the brain must interpret stimulus-evoked neural activity. This is challenging: The stochastic nature of the neural response renders its interpretation inherently uncertain. Perception would be optimized if the brain used Bayesian inference to interpret inputs in light of expectations derived from experience. Bayesian inference would improve perception on average but cause illusions when stimuli violate expectation. Intriguingly, tactile, auditory, and visual perception are all prone to length contraction illusions, characterized by the dramatic underestimation of the distance between punctate stimuli delivered in rapid succession; the origin of these illusions has been mysterious. We previously proposed that length contraction illusions occur because the brain interprets punctate stimulus sequences using Bayesian inference with a low-velocity expectation. A novel prediction of our Bayesian observer model is that length contraction should intensify if stimuli are made more difficult to localize. Here we report a tactile psychophysical study that tested this prediction. Twenty humans compared two distances on the forearm: a fixed reference distance defined by two taps with 1-s temporal separation and an adjustable comparison distance defined by two taps with temporal separation t ≤ 1 s. We observed significant length contraction: As t was decreased, participants perceived the two distances as equal only when the comparison distance was made progressively greater than the reference distance. Furthermore, the use of weaker taps significantly enhanced participants' length contraction. These findings confirm the model's predictions, supporting the view that the spatiotemporal percept is a best estimate resulting from a Bayesian inference process.
Nanotechnology and statistical inference
Vesely, Sara; Vesely, Leonardo; Vesely, Alessandro
2017-08-01
We discuss some problems that arise when applying statistical inference to data with the aim of disclosing new func-tionalities. A predictive model analyzes the data taken from experiments on a specific material to assess the likelihood that another product, with similar structure and properties, will exhibit the same functionality. It doesn't have much predictive power if vari-ability occurs as a consequence of a specific, non-linear behavior. We exemplify our discussion on some experiments with biased dice.
Directory of Open Access Journals (Sweden)
Kevin H. Knuth
2012-06-01
Full Text Available We present a simple and clear foundation for finite inference that unites and significantly extends the approaches of Kolmogorov and Cox. Our approach is based on quantifying lattices of logical statements in a way that satisfies general lattice symmetries. With other applications such as measure theory in mind, our derivations assume minimal symmetries, relying on neither negation nor continuity nor differentiability. Each relevant symmetry corresponds to an axiom of quantification, and these axioms are used to derive a unique set of quantifying rules that form the familiar probability calculus. We also derive a unique quantification of divergence, entropy and information.
Nonparametric statistical inference
Gibbons, Jean Dickinson
2010-01-01
Overall, this remains a very fine book suitable for a graduate-level course in nonparametric statistics. I recommend it for all people interested in learning the basic ideas of nonparametric statistical inference.-Eugenia Stoimenova, Journal of Applied Statistics, June 2012… one of the best books available for a graduate (or advanced undergraduate) text for a theory course on nonparametric statistics. … a very well-written and organized book on nonparametric statistics, especially useful and recommended for teachers and graduate students.-Biometrics, 67, September 2011This excellently presente
DEFF Research Database (Denmark)
Andersen, Jesper; Lawall, Julia
2010-01-01
A key issue in maintaining Linux device drivers is the need to keep them up to date with respect to evolutions in Linux internal libraries. Currently, there is little tool support for performing and documenting such changes. In this paper we present a tool, spdiff, that identifies common changes...... developers can use it to extract an abstract representation of the set of changes that others have made. Our experiments on recent changes in Linux show that the inferred generic patches are more concise than the corresponding patches found in commits to the Linux source tree while being safe with respect...
Tensor Effect on Bubble Nuclei
Institute of Scientific and Technical Information of China (English)
WANG Yan-Zhao; GU Jian-Zhong; ZHANG Xi-Zhen; DONG Jian-Min
2011-01-01
In the framework of the Hartree-Fock-Bogoliubov (HFB) approach with Skyrme interactions SLy5+T, SLy5+Tw and several sets of TIJ parametrizations, I.e. The Skyrme interaction parametrizations including the tensor terms, the proton density distribution in 34Si and 46Ar nuclei is calculated with and without the tensor force. It is shown that the bubble effect in 34Si does not depend a great deal on the Skyrme parametrization and the proton density distribution in 34Si is hardly influenced by the tensor force. As to 46Ar, the SLy5+Tw parametrization favors the formation of the bubble structure due to the inversion between the 2s1/2 and 1d3/2 orbits (2s1/2-ld3/2 inversion). The inversion mechanism induced by the SLy5+Tw interaction is analyzed based on the proton single-particle spectra obtained from the SLy5 and SLy5+Tw interactions as well as the wave functions of the 2s1/2 and 1d3/2 states.%In the framework of the Hartree-Fock-Bogoliubov (HFB) approach with Skyrme interactions SLy5+ T,SLy5+ Tω and several sets of TIJ parametrizations,i.e.the Skyrme interaction pararmetrizations including the tensor terms,the proton density distribution in 34Si and 46 Ar nuclei is calculated with and without the tensor force.It is shown that the bubble effect in 34Si does not depend a great deal on the Skyrme parametrization and the proton density distribution in 34Si is hardly influenced by the tensor force.As to 46Ar,the SLy5+ Tω parametrization favors the formation of the bubble structure due to the inversion between the 2s1/2 and 1d3/2 orbits (2s1/2-1d3/2 inversion).The inversion mechanism induced by the SLy5+ Tω interaction is analyzed based on the proton single-particle spectra obtained from the SLy5 and SLy5+ Tω interactions as well as the wave functions of the 2s1/2 and 1d3/2 states.The study of exotic nuclear structures has been a hot topic in nuclear physics.[1-4] Exotic nuclei are unstabile,superheavy nuclei,halo nuclei and so forth,whose structures are quite different
Brain imaging, forward inference, and theories of reasoning.
Heit, Evan
2014-01-01
This review focuses on the issue of how neuroimaging studies address theoretical accounts of reasoning, through the lens of the method of forward inference (Henson, 2005, 2006). After theories of deductive and inductive reasoning are briefly presented, the method of forward inference for distinguishing between psychological theories based on brain imaging evidence is critically reviewed. Brain imaging studies of reasoning, comparing deductive and inductive arguments, comparing meaningful versus non-meaningful material, investigating hemispheric localization, and comparing conditional and relational arguments, are assessed in light of the method of forward inference. Finally, conclusions are drawn with regard to future research opportunities.
Brain Imaging, Forward Inference, and Theories of Reasoning
Directory of Open Access Journals (Sweden)
Evan eHeit
2015-01-01
Full Text Available This review focuses on the issue of how neuroimaging studies address theoretical accounts of reasoning, through the lens of the method of forward inference (Henson, 2005, 2006. After theories of deductive and inductive reasoning are briefly presented, the method of forward inference for distinguishing between psychological theories based on brain imaging evidence is critically reviewed. Brain imaging studies of reasoning, comparing deductive and inductive arguments, comparing meaningful versus non-meaningful material, investigating hemispheric localization, and comparing conditional and relational arguments, are assessed in light of the method of forward inference. Finally, conclusions are drawn with regard to future research opportunities.
Microscopic properties of superdeformed nuclei
Energy Technology Data Exchange (ETDEWEB)
Karlsson, Lennart B
1999-04-01
Many high spin rotational bands in superdeformed nuclei have been found in the A 140 - 150 region, but so far no linking transitions to known normal-deformed states have been found in these nuclei. Therefore, configuration and spin assignments have to be based on indirect spectroscopic information. Identical bands were first discovered in this region of superdeformed states. At present, some identical bands have also been found at normal deformation, but such bands are more common at superdeformation. Recently lifetime measurements have given relative quadrupole moments with high accuracy. Spectroscopic quantities are calculated using the configuration constrained cranked Nilsson-Strutinsky model with the modified oscillator potential. In a statistical study the occurrence of identical bands is tested. Comparing superdeformed and normal deformed nuclei, the higher possibility for identical bands at superdeformation is understood from calculated reduced widths of the E{sub {gamma}} and J{sup (2)} distributions. The importance of high-N orbitals for identical bands is also discussed. Additivity of electric quadrupole moment contributions in the superdeformed A - 150 region is discussed with the nucleus {sup 152}Dy as a `core`. In analytic harmonic oscillator calculations, the effective electric quadrupole moment q{sub eff}, i.e. the change in the total quadrupole moment caused by the added particle, is expressed as a simple function of the single-particle mass, quadrupole moment q{sub {nu}}. Also in realistic calculations, simple relations between q{sub eff} and q{sub {nu}} can be used to estimate the total electric quadrupole moment, e.g. for the nucleus {sup 142}Sm, by adding the effect of 10 holes, to the total electric quadrupole moment of {sup 152}Dy. Furthermore, tools are given for estimating the quadrupole moment for possible configurations in the superdeformed A - 150 region. For the superdeformed region around {sup 143}Eu, configuration and spin assignments
Breakup Densities of Hot Nuclei.
Viola, Vic
2006-04-01
Breakup densities of hot ^197Au-like residues have been deduced from the systematic trends of Coulomb parameters required to fit intermediate-mass-fragment kinetic-energy spectra. The results indicate emission from nuclei near normal nuclear density below an excitation energy E*/A .3ex˜x 5 MeV. Temperatures derived from these data with a density-dependent Fermi-gas model yield a nuclear caloric curve that is generally consistent with those derived from isotope ratios.
Double pion photoproduction in nuclei
Energy Technology Data Exchange (ETDEWEB)
Gomez Tejedor, J.A. [Departamento de Fisica Teorica, Valencia (Spain); Vicente-Vacas, M.J. [Departamento de Fisica Teorica, Valencia (Spain); Oset, E. [Departamento de Fisica Teorica, Valencia (Spain)
1995-06-19
The inclusive A({gamma},{pi}{sup +}{pi}{sup -})X reaction is studied theoretically. A sizable enhancement of the cross section is found, in comparison with the scaling of the deuteron cross section ({sigma}{sub d} A/2). This enhancement is due to the modifications in the nuclear medium of the {gamma}N {yields}{pi}{pi}N amplitude and the pion dispersion relation. The enhancement is found to be bigger than the one already observed in the ({pi},{pi}{pi}) reaction in nuclei. ((orig.)).
Statistical inferences in phylogeography
DEFF Research Database (Denmark)
Nielsen, Rasmus; Beaumont, Mark A
2009-01-01
In conventional phylogeographic studies, historical demographic processes are elucidated from the geographical distribution of individuals represented on an inferred gene tree. However, the interpretation of gene trees in this context can be difficult as the same demographic/geographical process ...... may also be challenged by computational problems or poor model choice. In this review, we will describe the development of statistical methods in phylogeographic analysis, and discuss some of the challenges facing these methods....... can randomly lead to multiple different genealogies. Likewise, the same gene trees can arise under different demographic models. This problem has led to the emergence of many statistical methods for making phylogeographic inferences. A popular phylogeographic approach based on nested clade analysis...... is challenged by the fact that a certain amount of the interpretation of the data is left to the subjective choices of the user, and it has been argued that the method performs poorly in simulation studies. More rigorous statistical methods based on coalescence theory have been developed. However, these methods...
Moment inference from tomograms
Day-Lewis, F. D.; Chen, Y.; Singha, K.
2007-01-01
Time-lapse geophysical tomography can provide valuable qualitative insights into hydrologic transport phenomena associated with aquifer dynamics, tracer experiments, and engineered remediation. Increasingly, tomograms are used to infer the spatial and/or temporal moments of solute plumes; these moments provide quantitative information about transport processes (e.g., advection, dispersion, and rate-limited mass transfer) and controlling parameters (e.g., permeability, dispersivity, and rate coefficients). The reliability of moments calculated from tomograms is, however, poorly understood because classic approaches to image appraisal (e.g., the model resolution matrix) are not directly applicable to moment inference. Here, we present a semi-analytical approach to construct a moment resolution matrix based on (1) the classic model resolution matrix and (2) image reconstruction from orthogonal moments. Numerical results for radar and electrical-resistivity imaging of solute plumes demonstrate that moment values calculated from tomograms depend strongly on plume location within the tomogram, survey geometry, regularization criteria, and measurement error. Copyright 2007 by the American Geophysical Union.
Pairing correlations in exotic nuclei
Sagawa, H
2012-01-01
The BCS and HFB theories which can accommodate the pairing correlations in the ground states of atomic nuclei are presented. As an application of the pairing theories, we investigate the spatial extension of weakly bound Ne and C isotopes by taking into account the pairing correlation with the Hartree-Fock-Bogoliubov (HFB) method and a 3-body model, respectively. We show that the odd-even staggering in the reaction cross sections of $^{30,31,32}$Ne and $^{14,15,16}$C are successfully reproduced, and thus the staggering can be attributed to the unique role of pairing correlations in nuclei far from the stability line. A correlation between a one-neutron separation energy and the anti-halo effect is demonstrated for $s$- and p-waves using the HFB wave functions. We also propose effective density-dependent pairing interactions which reproduce both the neutron-neutron ($nn$) scattering length at zero density and the neutron pairing gap in uniform matter. Then, we apply these interactions to study pairing gaps in ...
Selfconsistent calculations for hyperdeformed nuclei
Energy Technology Data Exchange (ETDEWEB)
Molique, H.; Dobaczewski, J.; Dudek, J.; Luo, W.D. [Universite Louis Pasteur, Strasbourg (France)
1996-12-31
Properties of the hyperdeformed nuclei in the A {approximately} 170 mass range are re-examined using the self-consistent Hartree-Fock method with the SOP parametrization. A comparison with the previous predictions that were based on a non-selfconsistent approach is made. The existence of the {open_quotes}hyper-deformed shell closures{close_quotes} at the proton and neutron numbers Z=70 and N=100 and their very weak dependence on the rotational frequency is suggested; the corresponding single-particle energy gaps are predicted to play a role similar to that of the Z=66 and N=86 gaps in the super-deformed nuclei of the A {approximately} 150 mass range. Selfconsistent calculations suggest also that the A {approximately} 170 hyperdeformed structures have neglegible mass asymmetry in their shapes. Very importantly for the experimental studies, both the fission barriers and the {open_quotes}inner{close_quotes} barriers (that separate the hyperdeformed structures from those with smaller deformations) are predicted to be relatively high, up to the factor of {approximately}2 higher than the corresponding ones in the {sup 152}Dy superdeformed nucleus used as a reference.
Thermal instability of cell nuclei
Warmt, Enrico; Kießling, Tobias R.; Stange, Roland; Fritsch, Anatol W.; Zink, Mareike; Käs, Josef A.
2014-07-01
DNA is known to be a mechanically and thermally stable structure. In its double stranded form it is densely packed within the cell nucleus and is thermo-resistant up to 70\\:^\\circ {\\rm{C}}. In contrast, we found a sudden loss of cell nuclei integrity at relatively moderate temperatures ranging from 45 to 55\\:^\\circ {\\rm{C}}. In our study, suspended cells held in an optical double beam trap were heated under controlled conditions while monitoring the nuclear shape. At specific critical temperatures, an irreversible sudden shape transition of the nuclei was observed. These temperature induced transitions differ in abundance and intensity for various normal and cancerous epithelial breast cells, which clearly characterizes different cell types. Our results show that temperatures slightly higher than physiological conditions are able to induce instabilities of nuclear structures, eventually leading to cell death. This is a surprising finding since recent thermorheological cell studies have shown that cells have a lower viscosity and are thus more deformable upon temperature increase. Since the nucleus is tightly coupled to the outer cell shape via the cytoskeleton, the force propagation of nuclear reshaping to the cell membrane was investigated in combination with the application of cytoskeletal drugs.
Inferring Planetary Obliquity Using Rotational & Orbital Photometry
Schwartz, Joel C; Haggard, Hal M; Pallé, Eric; Cowan, Nicolas B
2015-01-01
The obliquity of a terrestrial planet is an important clue about its formation and critical to its climate. Previous studies using simulated photometry of Earth show that continuous observations over most of a planet's orbit can be inverted to infer obliquity. We extend this approach to single-epoch observations for planets with arbitrary albedo maps. For diffuse reflection, the flux seen by a distant observer is the product of the planet's albedo map, the host star's illumination, and the observer's visibility of different planet regions. It is useful to treat the product of illumination and visibility as the kernel of a convolution; this kernel is unimodal and symmetric. For planets with unknown obliquity, the kernel is not known a priori, but could be inferred by fitting a rotational light curve. We analyze this kernel under different viewing geometries, finding it well described by its longitudinal width and latitudinal position. We use Monte Carlo simulation to estimate uncertainties on these kernel char...
Excited nuclei in neutron star crusts
Takibayev, Nurgali; Nasirova, Diana
2012-01-01
The paper considers the chains of successive electron capture reactions by nuclei of the iron group which take place in the crystal structures of neutron star envelopes. It is shown that as a result of such reactions the daughter nuclei in excited states accumulate within certain layers of neutron star crusts. The phonon model of interactions is proposed between the excited nuclei in the crystalline structure, as well as formation of highly excited nuclear states which emit neutrons and higher energy photons.
Review of metastable states in heavy nuclei
Dracoulis, G. D.; Walker, P. M.; Kondev, F. G.
2016-07-01
The structure of nuclear isomeric states is reviewed in the context of their role in contemporary nuclear physics research. Emphasis is given to high-spin isomers in heavy nuclei, with A≳ 150 . The possibility to exploit isomers to study some of the most exotic nuclei is a recurring theme. In spherical nuclei, the role of octupole collectivity is discussed in detail, while in deformed nuclei the limitations of the K quantum number are addressed. Isomer targets and isomer beams are considered, along with applications related to energy storage, astrophysics, medicine, and experimental advances.
Bayesian inference in geomagnetism
Backus, George E.
1988-01-01
The inverse problem in empirical geomagnetic modeling is investigated, with critical examination of recently published studies. Particular attention is given to the use of Bayesian inference (BI) to select the damping parameter lambda in the uniqueness portion of the inverse problem. The mathematical bases of BI and stochastic inversion are explored, with consideration of bound-softening problems and resolution in linear Gaussian BI. The problem of estimating the radial magnetic field B(r) at the earth core-mantle boundary from surface and satellite measurements is then analyzed in detail, with specific attention to the selection of lambda in the studies of Gubbins (1983) and Gubbins and Bloxham (1985). It is argued that the selection method is inappropriate and leads to lambda values much larger than those that would result if a reasonable bound on the heat flow at the CMB were assumed.
Inferring the eccentricity distribution
Hogg, David W; Bovy, Jo
2010-01-01
Standard maximum-likelihood estimators for binary-star and exoplanet eccentricities are biased high, in the sense that the estimated eccentricity tends to be larger than the true eccentricity. As with most non-trivial observables, a simple histogram of estimated eccentricities is not a good estimate of the true eccentricity distribution. Here we develop and test a hierarchical probabilistic method for performing the relevant meta-analysis, that is, inferring the true eccentricity distribution, taking as input the likelihood functions for the individual-star eccentricities, or samplings of the posterior probability distributions for the eccentricities (under a given, uninformative prior). The method is a simple implementation of a hierarchical Bayesian model; it can also be seen as a kind of heteroscedastic deconvolution. It can be applied to any quantity measured with finite precision--other orbital parameters, or indeed any astronomical measurements of any kind, including magnitudes, parallaxes, or photometr...
Inferring deterministic causal relations
Daniusis, Povilas; Mooij, Joris; Zscheischler, Jakob; Steudel, Bastian; Zhang, Kun; Schoelkopf, Bernhard
2012-01-01
We consider two variables that are related to each other by an invertible function. While it has previously been shown that the dependence structure of the noise can provide hints to determine which of the two variables is the cause, we presently show that even in the deterministic (noise-free) case, there are asymmetries that can be exploited for causal inference. Our method is based on the idea that if the function and the probability density of the cause are chosen independently, then the distribution of the effect will, in a certain sense, depend on the function. We provide a theoretical analysis of this method, showing that it also works in the low noise regime, and link it to information geometry. We report strong empirical results on various real-world data sets from different domains.
Response of Cloud Condensation Nuclei (> 50 nm) to changes in ion-nucleation
DEFF Research Database (Denmark)
Svensmark, Henrik; Enghoff, Martin B.; Pedersen, Jens Olaf Pepke
2012-01-01
In experiments where ultraviolet light produces aerosols from trace amounts of ozone, sulphur dioxide, and water vapour, the number of additional small particles produced by ionization by gamma sources all grow up to diameters larger than 50 nm, appropriate for cloud condensation nuclei. This res......In experiments where ultraviolet light produces aerosols from trace amounts of ozone, sulphur dioxide, and water vapour, the number of additional small particles produced by ionization by gamma sources all grow up to diameters larger than 50 nm, appropriate for cloud condensation nuclei...
Efimov effect in 2-neutron halo nuclei
Indian Academy of Sciences (India)
Indranil Mazumdar
2010-07-01
This paper presents an overview of our theoretical investigations in search of Efimov states in light 2-neutron halo nuclei. The calculations have been carried out within a three-body formalism, assuming a compact core and two valence neutrons forming the halo. The calculations provide strong evidence for the occurrence of at least two Efimov states in 20C nucleus. These excited states move into the continuum as the two-body (core-neutron) binding energy is increased and show up as asymmetric resonances in the elastic scattering cross-section of the n- 19C system. The Fano mechanism is invoked to explain the asymmetry. The calculations have been extended to 38Mg, 32Ne and a hypothetical case of a very heavy core ( = 100) with two valence neutrons. In all these cases the Efimov states show up as resonances as the two-body energy is increased. However, in sharp contrast, the Efimov states, for a system of three equal masses, show up as virtual states beyond a certain value of the two-body interaction.
Admissibility of logical inference rules
Rybakov, VV
1997-01-01
The aim of this book is to present the fundamental theoretical results concerning inference rules in deductive formal systems. Primary attention is focused on: admissible or permissible inference rules the derivability of the admissible inference rules the structural completeness of logics the bases for admissible and valid inference rules. There is particular emphasis on propositional non-standard logics (primary, superintuitionistic and modal logics) but general logical consequence relations and classical first-order theories are also considered. The book is basically self-contained and
Dipole oscillation modes in $\\alpha$-clustering light nuclei
He, W B; Cao, X G; Cai, X Z; Zhang, G Q
2016-01-01
The alpha cluster states are discussed in an extended quantum molecular dynamics (EQMD) model frame. Different alpha cluster structures are studied in details, such as $^8$Be two-alpha cluster structure, $^{12}$C triangle structure, $^{12}$C chain structure, $^{16}$O chain structure, $^{16}$O kite structure, and $^{16}$O square structure. The properties like width of wave packets for different alpha clusters, momentum distribution, and the binding energy among alpha clusters are studied. It is also discussed how the $\\alpha$ cluster degree of freedom affects nuclear collective vibrations. The different $\\alpha$ cluster configurations in $^{12}$C and $^{16}$O have corresponding characteristic spectra of GDR and the coherence of different alpha clusters's dipole oscillation are described in details. The number and centroid energies of peaks in the GDR spectra can be reasonably explained by the geometrical and dynamical symmetries of $\\alpha$-clustering configurations. The GDR can be regarded as a very effective...
Electron scattering disintegration processes on light nuclei in covariant approach
Kuznietsov, P. E.; Kasatkin, Yu. A.; Klepikov, V. F.
2016-07-01
We provide general analysis of electro-break up process of compound scalar system. We use covariant approach with conserved EM current, which gives the ability to include strong interaction into QED. Therefore, we receive the ability to describe disintegration processes on nonlocal matter fields applying standard Feynman rules of QED. Inclusion of phase exponent into wave function receives a physical sense while we deal with the dominance of strong interaction in the process. We apply Green's function (GF) formalism to describe disintegration processes. Generalized gauge invariant electro-break up process amplitude is considered. One is a sum of traditional pole series and the regular part. We explore the deposits of regular part of amplitude, and its physical sense. A transition from virtual to real photon considered in photon point limit. The general analysis for electro-break up process of component scalar system is given. Precisely conserved nuclear electromagnetic currents at arbitrary square of transited momentum are received. The only undefined quantity in theory is vertex function. Therefore, we have the opportunity to describe electron scattering processes taking into account minimal necessary set of parameters.
Electron scattering disintegration processes on light nuclei in covariant approach
Directory of Open Access Journals (Sweden)
Kuznietsov P.E.
2016-01-01
Full Text Available We provide general analysis of electro-break up process of compound scalar system. We use covariant approach with conserved EM current, which gives the ability to include strong interaction into QED. Therefore, we receive the ability to describe disintegration processes on nonlocal matter fields applying standard Feynman rules of QED. Inclusion of phase exponent into wave function receives a physical sense while we deal with the dominance of strong interaction in the process. We apply Green’s function (GF formalism to describe disintegration processes. Generalized gauge invariant electro-break up process amplitude is considered. One is a sum of traditional pole series and the regular part. We explore the deposits of regular part of amplitude, and its physical sense. A transition from virtual to real photon considered in photon point limit. The general analysis for electro-break up process of component scalar system is given. Precisely conserved nuclear electromagnetic currents at arbitrary square of transited momentum are received. The only undefined quantity in theory is vertex function. Therefore, we have the opportunity to describe electron scattering processes taking into account minimal necessary set of parameters.
s-particle doublets in certain light nuclei
Bilaniuk, O.M.; French, J.B.
1960-01-01
The splitting of an s-particle doublet in B11 is examined to see what information it gives about the effective 1p-2s shell model interaction and it is concluded that the small splitting is explainable by an interaction whose spin dependence is primarily of s1 · s2t1 · t2 nature. Certain other s-doub
β-Decay of Light Neutron-Rich Nuclei
Institute of Scientific and Technical Information of China (English)
何超; 华辉; 李湘庆; 汪波
2012-01-01
The β-decays of neutron-rich carbon, nitrogen and fluorine isotopes have been systematically studied using the OXBASH shell Model. In the psd, spsd and spsdpf model space, we use the WBP interaction to calculate the half-lives and neutron emission probabilities of neutron- rich carbon and nitrogen isotopes, respectively. With the USD （W） and CW interactions, we calculate the half-lives and neutron emission probabilities of neutron-rich fluorine isotope in the sd model space, respectively. The calculated half-lives and neutron emission probabilities reproduce recent experimental data very well. It seems to show that the particles of the neutron-rich carbon and nitrogen isotopes are mainly excited in the spsd space. The β-decay of 21N to the neutron bound states in 210 is mostly the first forbidden transition which makes the neutron emission probability increase. The theoretical calculation of β-decay of 25F to 25Ne with CW interaction shows that CW interaction is better than USD interaction.
Binding in light nuclei: Statistical NN uncertainties vs Computational accuracy
Navarro Pérez, R.; Nogga, A.; Amaro, J. E.; Ruiz Arriola, E.
2016-08-01
We analyse the impact of the statistical uncertainties of the the nucleon-nucleon interaction, based on the Granada-2013 np-pp database, on the binding energies of the triton and the alpha particle using a bootstrap method, by solving the Faddeev equations for 3H and the Yakubovsky equations for 4He respectively. We check that in practice about 30 samples prove enough for a reliable error estimate. An extrapolation of the well fulfilled Tjon-line correlation predicts the experimental binding of the alpha particle within uncertainties. Presented by RNP at Workshop for young scientists with research interests focused on physics at FAIR 14-19 February 2016 Garmisch-Partenkirchen (Germany).
New measurements of the EMC effect in very light nuclei
Seely, J; Gaskell, D; Arrington, J; Fomin, N; Solvignon, P; Asaturyan, R; Benmokhtar, F; Boeglin, W; Boillat, B; Bosted, P; Brüll, A; Bukhari, M H S; Christy, M E; Clasie, B; Connell, S; Dalton, M; Day, D; Dunne, J; Dutta, D; Fassi, L El; Ent, R; Fenker, H; Filippone, B W; Gao, H; Hill, C; Holt, R J; Horn, T; Hungerford, E; Jones, M K; Jourdan, J; Kalantarians, N; Keppel, C E; Kiselev, D; Kotulla, M; Lee, C; Lung, A F; Malace, S; Meekins, D G; Mertens, T; Mkrtchyan, H; Navasardyan, T; Niculescu, G; Niculescu, I; Nomura, H; Okayasu, Y; Opper, A K; Perdrisat, C; Potterveld, D H; Punjabi, V; Qian, X; Reimer, P E; Roche, J; Rodriguez, V M; Rondon, O; Schulte, E; Segbefia, E; Slifer, K; Smith, G R; Tadevosyan, V; Tajima, S; Tang, L; Testa, G; Trojer, R; Tvaskis, V; Villano, A; Vulcan, W F; Wesselmann, F R; Wood, S A; Wright, J; Yuan, L; Zheng, X
2009-01-01
New Jefferson Lab data are presented on the nuclear dependence of the inclusive cross section from 2H, 3He, 4He, 9Be and 12C for 0.3
Quantum Monte Carlo Studies of Relativistic Effects in Light Nuclei
Forest, J L; Arriaga, A
1999-01-01
Relativistic Hamiltonians are defined as the sum of relativistic one-body kinetic energy, two- and three-body potentials and their boost corrections. In this work we use the variational Monte Carlo method to study two kinds of relativistic effects in the binding energy of 3H and 4He. The first is due to the nonlocalities in the relativistic kinetic energy and relativistic one-pion exchange potential (OPEP), and the second is from boost interaction. The OPEP contribution is reduced by about 15% by the relativistic nonlocality, which may also have significant effects on pion exchange currents. However, almost all of this reduction is canceled by changes in the kinetic energy and other interaction terms, and the total effect of the nonlocalities on the binding energy is very small. The boost interactions, on the other hand, give repulsive contributions of 0.4 (1.9) MeV in 3H (4He) and account for 37% of the phenomenological part of the three-nucleon interaction needed in the nonrelativistic Hamiltonians.
Search for the Jacobi shape transition in light nuclei
Maj, A; Brekiesz, M; Grebosz, J; Meczynski, W; Styczen, J; Zieblinski, M; Zuber, K; Bracco, A; Camera, F; Benzoni, G; Million, B; Blasi, N; Brambilla, S; Leoni, S; Pignanelli, M; Wieland, O; Nyberg, J; Kicinska-Habior, M; Petrache, C M; Dudek, J; Pomorski, K
2003-01-01
The gamma-rays following the reaction 105 MeV 18O + 28Si have been measured using the EUROBALL IV, HECTOR and EUCLIDES arrays in order to investigate the predicted Jacobi shape transition. The high-energy gamma-ray spectrum from the GDR decay indicates a presence of large deformations in hot 46Ti nucleus, in agreement with new theoretical calculations based on the Rotating Liquid Drop model.
Search for the Jacobi shape transition in light nuclei
Energy Technology Data Exchange (ETDEWEB)
Maj, A.; Kmiecik, M.; Brekiesz, M.; Grebosz, J.; Meczynski, W.; Styczen, J.; Zieblinski, M.; Zuber, K. [The Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, ul. Radzikowskiego 152, PL-31342, Krakow (Poland); Bracco, A.; Camera, F.; Benzoni, G.; Million, B.; Blasi, N.; Brambilla, S.; Leoni, S.; Pignanelli, M.; Wieland, O. [Dipartimento di Fisica and INFN sez. Milano, I-20133, Milano (Italy); Herskind, B. [The Niels Bohr Insitute, Blegdamsvej 17, DK-2100, Copenhagen (Denmark); Bednarczyk, P. [The Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, ul. Radzikowskiego 152, PL-31342, Krakow (Poland); Institut de Recherches Subatomiques, 23 rue du Loess, BP28, F-67037, Strasbourg (France); Curien, D. [Institut de Recherches Subatomiques, 23 rue du Loess, BP28, F-67037, Strasbourg (France); Vivien, J.P.; Farnea, E.; De Angelis, G.; Napoli, D.R.; Nyberg, J.; Kicinska-Habior, M.; Petrache, C.M.; Dudek, J.; Pomorski, K.
2004-04-01
The {gamma}-rays following the reaction 105 MeV {sup 18}O+{sup 28}Si have been measured using the EUROBALL IV, HECTOR and EUCLIDES arrays in order to investigate the predicted Jacobi shape transition. The high-energy {gamma}-ray spectrum from the GDR decay indicates the presence of large deformations in the hot {sup 46}Ti nucleus, in agreement with new theoretical calculations based on the rotating liquid-drop model. (orig.)
Clusterization of light nuclei and the Trojan Horse Method
Tumino, A.; Spitaleri, C.; Cherubini, S.; D'Agata, G.; Guardo, L.; Gulino, M.; Indelicato, I.; La Cognata, M.; Lamia, L.; Pizzone, R. G.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Spartá, R.
2017-06-01
The THM is a unique indirect technique to measure astrophysical rearrangement reactions down to astrophysical relevant energies, where direct experiments are unfeasible. This is done by measuring a suitable three body process in quasi free kinematics. The basic principles are recalled and some applications presented.
Binding in light nuclei: Statistical NN uncertainties vs Computational accuracy
Perez, R Navarro; Amaro, J E; Arriola, E Ruiz
2016-01-01
We analyse the impact of the statistical uncertainties of the the nucleon-nucleon interaction, based on the Granada-2013 np-pp database, on the binding energies of the triton and the alpha particle using a bootstrap method, by solving the Faddeev equations for $^3$H and the Yakubovsky equations for $^4$He respectively. We check that in practice about 30 samples prove enough for a reliable error estimate. An extrapolation of the well fulfilled Tjon-line correlation predicts the experimental binding of the alpha particle within uncertainties.
Electric dipole moments of light nuclei in effective field theory
Energy Technology Data Exchange (ETDEWEB)
Bsaisou, Jan; Liebig, Susanna; Minossi, David [Institut fuer Kernphysik, Forschungszentrum Juelich (Germany); Juelich Center for Hadron Physics, Forschungszentrum Juelich (Germany); Hanhart, Christoph; Nogga, Andreas; Vries, Jordy de; Wirzba, Andreas [Institut fuer Kernphysik, Forschungszentrum Juelich (Germany); Juelich Center for Hadron Physics, Forschungszentrum Juelich (Germany); Institute for Advanced Simulation, Forschungszentrum Juelich (Germany); JARA - Forces and Matter Experiments, Forschungszentrum Juelich (Germany); Meissner, UlfG. [Institut fuer Kernphysik, Forschungszentrum Juelich (Germany); Juelich Center for Hadron Physics, Forschungszentrum Juelich (Germany); Institute for Advanced Simulation, Forschungszentrum Juelich (Germany); JARA - Forces and Matter Experiments, Forschungszentrum Juelich (Germany); Helmholtz-Institut fuer Strahlen und Kernphysik, Universitaet Bonn (Germany)
2014-07-01
Electric dipole moments (EDMs) break parity (P) and time-reversal (T) symmetry and thus, by the CPT-theorem, CP-symmetry. Once measured, they will be unambiguous signs of new physics since CP-violation from the standard mechanism predicts EDMs that are experimentally inaccessible in the foreseeable future. We calculate within the framework of effective field theory the two-nucleon contributions to the EDMs of the deuteron, helion, and triton induced by P- and T-violating terms that arise from the QCD θ-term or dimension-6 sources of physics beyond the Standard Model (SM). We demonstrate what insights into physics beyond the SM can be gained from a suitable combination of measurements and, if needed, supplementary lattice QCD calculations.
Evolution of Surface Deformations of Weakly-Bound Nuclei in the Continuum
Pei, J C; Xu, F R
2013-01-01
We study weakly-bound deformed nuclei based on coordinate-space Skyrme Hartree-Fock-Bogoliubov approach , in which a large box is employed for treating the continuum and surface diffuseness. Approaching the limit of core-halo deformation decoupling, calculations found an exotic "egg"-like structure consisting of a spherical core plus a prolate halo in $^{38}$Ne, in which the resonant continuum plays an essential role. Generally the halo probability and the decoupling effect in heavy nuclei are reduced compared to light nuclei, due to denser level densities around Fermi surfaces. However, deformed halos in medium-mass nuclei are possible with sparse levels of negative parity, for example, in $^{110}$Ge. The surface deformations of pairing density distributions are also influenced by the decoupling effect and are sensitive to the effective pairing Hamiltonian.
Cavitation Nuclei: Experiments and Theory
DEFF Research Database (Denmark)
Mørch, Knud Aage
2009-01-01
The Swedish astrophysicist and Nobel Prize winner Hannes Alfven said: Theories come and go - the experiment is here forever. Often a theory, which we set up to describe an observed physical phenomenon, suffers from the lack of knowledge of decisive parameters, and therefore at best the theory...... becomes insufficient. Contrary, the experiment always reveals nature itself, though at prevailing experimental conditions. With essential parameters being out of control and even maybe unidentified, apparently similar experiments may deviate way beyond our expectations. However, these discrepancies offer...... us a chance to reflect on the character of the unknown parameters. In this way non-concordant experimental results may hold the key to the development of better theories - and to new experiments for the testing of their validity. Cavitation and cavitation nuclei are phenomena of that character....
CAVITATION NUCLEI: EXPERIMENTS AND THEORY
Institute of Scientific and Technical Information of China (English)
MфRCH K. A.
2009-01-01
The Swedish astrophysicist and Nobel Prize winner Hannes Alfvén said: Theories come and go ─ the experiment is here forever. Often a theory, which we set up to describe an observed physical phenomenon, suffers from the lack of knowledge of decisive parameters, and therefore at best the theory becomes insufficient. Contrary, the experiment always reveals nature itself, though at prevailing experimental conditions. With essential parameters being out of control and even maybe unidentified, apparently similar experiments may deviate way beyond our expectations. However, these discrepancies offer us a chance to reflect on the character of the unknown parameters. In this way non-concordant experimental results may hold the key to the development of better theories – and to new experiments for the testing of their validity. Cavitation and cavitation nuclei are phenomena of that character.
Inclusive breakup of Borromean nuclei
Hussein, Mahir S; Frederico, Tobias
2016-01-01
We derive the inclusive breakup cross section of a three-fragment projectile nuclei, $a = b +x_1 + x_2$, in the spectator model. The resulting four-body cross section for observing $b$, is composed of the elastic breakup cross section which contains information about the correlation between the two participant fragments, and the inclusive non-elastic breakup cross section. This latter cross section is found to be a non-trivial four-body generalization of the Austern formula \\cite{Austern1987}, which is proportional to a matrix element of the form, $\\langle\\hat{\\rho}_{{x_1},{x_2}}\\left|\\left[W_{{x_1}} + W_{{x_2}} + W_{3B}\\right]\\right|\\hat{\\rho}_{{x_1}, {x_2}}\\rangle$. The new feature here is the three-body absorption, represented by the imaginary potential, $W_{3B}$. We analyze this type of absorption and supply ideas of how to calculate its contribution.
Formation of $\\phi$ mesic nuclei
Yamagata-Sekihara, J; Vacas, M J Vicente; Hirenzaki, S
2010-01-01
We study the structure and formation of the $\\phi$ mesic nuclei to investigate the in-medium modification of the $\\phi$-meson spectral function at finite density. We consider (${\\bar p},\\phi$), ($\\gamma,p$) and ($\\pi^-,n$) reactions to produce a $\\phi$-meson inside the nucleus and evaluate the effects of its medium modifications to the reaction cross sections. We also estimate the consequences of the uncertainties of the ${\\bar K}$ selfenergy in medium to the $\\phi$-nucleus interaction. We find that it may be possible to see a peak structure in the reaction spectra for the strong attractive potential cases. On the other hand, for strong absorptive interaction cases with relatively weak attractions, it is very difficult to observe clear peaks and we may need to know the spectrum shape in a wide energy region to deduce the properties of $\\phi$.
Quasifree kaon photoproduction on nuclei
Energy Technology Data Exchange (ETDEWEB)
Frank Lee; T. MART; Cornelius Bennhold; Lester Wright
2001-12-01
Investigations of the quasifree reaction A({gamma}, K Y)B are presented in the distorted wave impulse approximation (DWIA). For this purpose, we present a revised tree-level model of elementary kaon photoproduction that incorporates hadronic form factors consistent with gauge invariance, uses SU(3) values for the Born couplings and uses resonances consistent with multi-channel analyses. The potential of exclusive quasifree kaon photoproduction on nuclei to reveal details of the hyperon-nucleus interaction is examined. Detailed predictions for the coincidence cross section, the photon asymmetry, and the hyperon polarization and their sensitivities to the ingredients of the model are obtained for all six production channels. Under selected kinematics these observables are found to be sensitive to the hyperon-nucleus final state interaction. Some polarization observables are found to be insensitive to distortion effects, making them ideal tools to search for possible medium modifications of the elementary amplitude.
Thalamic nuclei segmentation in clinical 3T T1-weighted Images using high-resolution 7T shape models
Liu, Yuan; D'Haese, Pierre-François; Newton, Allen T.; Dawant, Benoit M.
2015-03-01
Accurate and reliable identification of thalamic nuclei is important for surgical interventions and neuroanatomical studies. This is a challenging task due to their small sizes and low intra-thalamic contrast in standard T1-weighted or T2- weighted images. Previously proposed techniques rely on diffusion imaging or functional imaging. These require additional scanning and suffer from the low resolution and signal-to-noise ratio in these images. In this paper, we aim to directly segment the thalamic nuclei in standard 3T T1-weighted images using shape models. We manually delineate the structures in high-field MR images and build high resolution shape models from a group of subjects. We then investigate if the nuclei locations can be inferred from the whole thalamus. To do this, we hierarchically fit joint models. We start from the entire thalamus and fit a model that captures the relation between the thalamus and large nuclei groups. This allows us to infer the boundaries of these nuclei groups and we repeat the process until all nuclei are segmented. We validate our method in a leave-one-out fashion with seven subjects by comparing the shape-based segmentations on 3T images to the manual contours. Results we have obtained for major nuclei (dice coefficients ranging from 0.57 to 0.88 and mean surface errors from 0.29mm to 0.72mm) suggest the feasibility of using such joint shape models for localization. This may have a direct impact on surgeries such as Deep Brain Stimulation procedures that require the implantation of stimulating electrodes in specific thalamic nuclei.
Time Delay Evolution of Five Active Galactic Nuclei
Indian Academy of Sciences (India)
A. Kovačević; L. Č. Popović; A. I. Shapovalova; D. Ilić; A. N. Burenkov; V. H. Chavushyan
2015-12-01
Here we investigate light curves of the continuum and emission lines of five type 1 active galactic nuclei (AGN) from our monitoring campaign, to test time-evolution of their time delays. Using both modeled and observed AGN light curves, we apply Gaussian kernel-based estimator to capture variation of local patterns of their time evolving delays. The largest variations of time delays of all objects occur in the period when continuum or emission lines luminosity is the highest. However, Gaussian kernel-based method shows instability in the case of NGC 5548, 3C 390.3, E1821+643 and NGC 4051 possibly due to numerical discrepancies between damped random walk (DRW) time scale of light curves and sliding time windows of the method. The temporal variations of time lags of Arp 102B can correspond to the real nature of the time lag evolution.
On the time delay evolution of five Active Galactic Nuclei
Kovacevic, Andjelka; Shapovalova, Alla I; Ilic, Dragana; Burenkov, Aleksandr N; Chavushyan, Vahram H
2015-01-01
Here we investigate light curves of the continuum and emission lines of five type 1 active galactic nuclei (AGN) from our monitoring campaign, to test time-evolution of their time delays.Using both modeled and observed AGN light curves we apply Gaussian-kernel based estimator to capture variation of local patterns of their time evolving delays. The largest variations of time delays of all objects occur in the period when continuum or emission lines luminosity is the highest. However, Gaussian kernel based method shows instability in the case of NGC 5548, 3C 390.3, E1821+643 and NGC 4051 possible due to numerical discrepancies between Damped Random Walk (DRW) time scale of light curves and sliding time windows of the method. The temporal variations of time lags of Arp 102B can correspond to the real nature of the time lag evolution.
DISTRIBUTIONS OF LONG-LIVED RADIOACTIVE NUCLEI PROVIDED BY STAR-FORMING ENVIRONMENTS
Energy Technology Data Exchange (ETDEWEB)
Fatuzzo, Marco [Department of Physics, Xavier University, Cincinnati, OH 45207 (United States); Adams, Fred C. [Physics Department, University of Michigan, Ann Arbor, MI 48109 (United States)
2015-11-01
Radioactive nuclei play an important role in planetary evolution by providing an internal heat source, which affects planetary structure and helps facilitate plate tectonics. A minimum level of nuclear activity is thought to be necessary—but not sufficient—for planets to be habitable. Extending previous work that focused on short-lived nuclei, this paper considers the delivery of long-lived radioactive nuclei to circumstellar disks in star forming regions. Although the long-lived nuclear species are always present, their abundances can be enhanced through multiple mechanisms. Most stars form in embedded cluster environments, so that disks can be enriched directly by intercepting ejecta from supernovae within the birth clusters. In addition, molecular clouds often provide multiple episodes of star formation, so that nuclear abundances can accumulate within the cloud; subsequent generations of stars can thus receive elevated levels of radioactive nuclei through this distributed enrichment scenario. This paper calculates the distribution of additional enrichment for {sup 40}K, the most abundant of the long-lived radioactive nuclei. We find that distributed enrichment is more effective than direct enrichment. For the latter mechanism, ideal conditions lead to about 1 in 200 solar systems being directly enriched in {sup 40}K at the level inferred for the early solar nebula (thereby doubling the abundance). For distributed enrichment from adjacent clusters, about 1 in 80 solar systems are enriched at the same level. Distributed enrichment over the entire molecular cloud is more uncertain, but can be even more effective.
Decay of heavy and superheavy nuclei
Indian Academy of Sciences (India)
K P Santhosh
2014-04-01
We present here, an overview and progress of the theoretical works on the isomeric state decay, decay fine structure of even–even, even–odd, odd–even and odd–odd nuclei, a study on the feasibility of observing decay chains from the isotopes of the superheavy nuclei = 115 in the range 271 ≤ ≤ 294 and the isotopes of = 117 in the range 270 ≤ ≤ 301, within the Coulomb and proximity potential model for deformed nuclei (CPPMDN). The computed half-lives of the favoured and unfavoured decay of nuclei in the range 67 ≤ ≤ 91 from both the ground state and isomeric state, are in good agreement with the experimental data and the standard deviation of half-life is found to be 0.44. From the fine structure studies done on various ranges of nuclei, it is evident that, for nearly all the transitions, the theoretical values show good match with the experimental values. This reveals that CPPMDN is successful in explaining the fine structure of even–even, even–odd, odd–even and odd–odd nuclei. Our studies on the decay of the superheavy nuclei 271−294115 and 270−301117 predict 4 chains consistently from 284,285,286115 nuclei and 5 chains and 3 chains consistently from 288−291117 and 292117, respectively. We thus hope that these studies on 284−286115 and 288−292117 will be a guide to future experiments.
Isovector multiphonon excitations in near spherical nuclei
Smirnova, N A; Pietralla, N; Van Isacker, P; Isacker, Piet Van; Mizusaki, Takahiro; Pietralla, Norbert; Smirnova, Nadya A.
2000-01-01
The lowest isoscalar and isovector quadrupole and octupole excitations in near spherical nuclei are studied within the the proton-neutron version of the interacting boson model including quadrupole and octupole bosons (sdf-IBM-2). The main decay modes of these states in near spherical nuclei are discussed.
Partial Dynamical Symmetry in Deformed Nuclei
Energy Technology Data Exchange (ETDEWEB)
Leviatan, A. [Racah Institute of Physics, The Hebrew University, Jerusalem 91904 (Israel)
1996-07-01
We discuss the notion of partial dynamical symmetry in relation to nuclear spectroscopy. Explicit forms of Hamiltonians with partial SU(3) symmetry are presented in the framework of the interacting boson model of nuclei. An analysis of the resulting spectrum and electromagnetic transitions demonstrates the relevance of such partial symmetry to the spectroscopy of axially deformed nuclei. {copyright} {ital 1996 The American Physical Society.}
Partial dynamical symmetry in deformed nuclei
Leviatan, A
1996-01-01
We discuss the notion of partial dynamical symmetry in relation to nuclear spectroscopy. Explicit forms of Hamiltonians with partial SU(3) symmetry are presented in the framework of the interacting boson model of nuclei. An analysis of the resulting spectrum and electromagnetic transitions demonstrates the relevance of such partial symmetry to the spectroscopy of axially deformed nuclei.
Positron production in collision of heavy nuclei
Khriplovich, I B
2016-01-01
We consider the electromagnetic production of positron in collision of slow heavy nuclei, with the simultaneously produced electron captured by one of the nuclei. The cross-section of the discussed process exceeds essentially the cross-section of $e^+e^-$ production.
RFP for the Comet Nuclei Tour (CONTOUR)
DEFF Research Database (Denmark)
Jørgensen, John Leif; Madsen, Peter Buch; Betto, Maurizio
1999-01-01
This document describes the ASC Star Tracker (performance, functionality, requirements etc.) to The Johns Hopkins University - Applied Physics Laboratory for their Comet Nuclei TOUR (CONTOUR) Program.......This document describes the ASC Star Tracker (performance, functionality, requirements etc.) to The Johns Hopkins University - Applied Physics Laboratory for their Comet Nuclei TOUR (CONTOUR) Program....
Variation of hadron masses in finite nuclei
Saitô, K; Tsushima, K; Saito, Koichi; Thomas, Anthony W.; Tsushima, Kazuo
1997-01-01
Using a self-consistent, Hartree description for both infinite nuclear matter and finite nuclei based on a relativistic quark model (the quark-meson coupling model), we investigate the variation of the masses of the non-strange vector mesons, the hyperons and the nucleon in infinite nuclear matter and in finite nuclei.
Energy Radiation of the Active Galactic Nuclei
Institute of Scientific and Technical Information of China (English)
TANG Zhi-Ming; WANG Yong-Jiu
2004-01-01
In the Hellings-Nordtvedt theory, we obtain some expressions of energy radiation and mass defect effect for a kind of the active galactic nuclei, which is meaningful to calculating the energy radiation in the procession of forming this kind of celestial bodies. This calculation can give some interpretation for energy source of the jet from the active galactic nuclei.
Mean-field models and exotic nuclei
Energy Technology Data Exchange (ETDEWEB)
Bender, M.; Buervenich, T.; Maruhn, J.A.; Greiner, W. [Inst. fuer Theoretische Physik, Univ. Frankfurt (Germany); Rutz, K. [Inst. fuer Theoretische Physik, Univ. Frankfurt (Germany)]|[Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Reinhard, P.G. [Inst. fuer Theoretische Physik, Univ. Erlangen (Germany)
1998-06-01
We discuss two widely used nuclear mean-field models, the relativistic mean-field model and the (nonrelativistic) Skyrme-Hartree-Fock model, and their capability to describe exotic nuclei. Test cases are superheavy nuclei and neutron-rich Sn isotopes. New information in this regime helps to fix hitherto loosely determined aspects of the models. (orig.)
Effective field theory for halo nuclei
Energy Technology Data Exchange (ETDEWEB)
Hagen, Philipp Robert
2014-02-19
such systems. We apply our model to some known and suspected halo nuclei, namely the light isotopes {sup 11}Li, {sup 14}Be and {sup 22}C and the hypothetical heavy atomic nucleus {sup 62}Ca. In particular, we calculate charge form factors, relative electric charge radii and dipole strengths as well as general dependencies of these observables on masses and one- and two-neutron separation energies. Our analysis of the {sup 62}Ca system provides evidence of Efimov physics along the Calcium isotope chain. Experimental key observables that facilitate a test of our findings are discussed.
Electromagnetically induced transparency with resonant nuclei in a cavity.
Röhlsberger, Ralf; Wille, Hans-Christian; Schlage, Kai; Sahoo, Balaram
2012-02-08
The manipulation of light-matter interactions by quantum control of atomic levels has had a profound impact on optical sciences. Such manipulation has many applications, including nonlinear optics at the few-photon level, slow light, lasing without inversion and optical quantum information processing. The critical underlying technique is electromagnetically induced transparency, in which quantum interference between transitions in multilevel atoms renders an opaque medium transparent near an atomic resonance. With the advent of high-brilliance, accelerator-driven light sources such as storage rings or X-ray lasers, it has become attractive to extend the techniques of optical quantum control to the X-ray regime. Here we demonstrate electromagnetically induced transparency in the regime of hard X-rays, using the 14.4-kiloelectronvolt nuclear resonance of the Mössbauer isotope iron-57 (a two-level system). We exploit cooperative emission from ensembles of the nuclei, which are embedded in a low-finesse cavity and excited by synchrotron radiation. The spatial modulation of the photonic density of states in a cavity mode leads to the coexistence of superradiant and subradiant states of nuclei, respectively located at an antinode and a node of the cavity field. This scheme causes the nuclei to behave as effective three-level systems, with two degenerate levels in the excited state (one of which can be considered metastable). The radiative coupling of the nuclear ensembles by the cavity field establishes the atomic coherence necessary for the cancellation of resonant absorption. Because this technique does not require atomic systems with a metastable level, electromagnetically induced transparency and its applications can be transferred to the regime of nuclear resonances, establishing the field of nuclear quantum optics.
An Inference Language for Imaging
DEFF Research Database (Denmark)
Pedemonte, Stefano; Catana, Ciprian; Van Leemput, Koen
2014-01-01
We introduce iLang, a language and software framework for probabilistic inference. The iLang framework enables the definition of directed and undirected probabilistic graphical models and the automated synthesis of high performance inference algorithms for imaging applications. The iLang framework...
Interactive Instruction in Bayesian Inference
DEFF Research Database (Denmark)
Khan, Azam; Breslav, Simon; Hornbæk, Kasper
2017-01-01
An instructional approach is presented to improve human performance in solving Bayesian inference problems. Starting from the original text of the classic Mammography Problem, the textual expression is modified and visualizations are added according to Mayer’s principles of instruction...... that an instructional approach to improving human performance in Bayesian inference is a promising direction....
Causal Inference and Developmental Psychology
Foster, E. Michael
2010-01-01
Causal inference is of central importance to developmental psychology. Many key questions in the field revolve around improving the lives of children and their families. These include identifying risk factors that if manipulated in some way would foster child development. Such a task inherently involves causal inference: One wants to know whether…
Causal Inference and Developmental Psychology
Foster, E. Michael
2010-01-01
Causal inference is of central importance to developmental psychology. Many key questions in the field revolve around improving the lives of children and their families. These include identifying risk factors that if manipulated in some way would foster child development. Such a task inherently involves causal inference: One wants to know whether…
Active inference and robot control: a case study
Nizard, Ange; Friston, Karl; Pezzulo, Giovanni
2016-01-01
Active inference is a general framework for perception and action that is gaining prominence in computational and systems neuroscience but is less known outside these fields. Here, we discuss a proof-of-principle implementation of the active inference scheme for the control or the 7-DoF arm of a (simulated) PR2 robot. By manipulating visual and proprioceptive noise levels, we show under which conditions robot control under the active inference scheme is accurate. Besides accurate control, our analysis of the internal system dynamics (e.g. the dynamics of the hidden states that are inferred during the inference) sheds light on key aspects of the framework such as the quintessentially multimodal nature of control and the differential roles of proprioception and vision. In the discussion, we consider the potential importance of being able to implement active inference in robots. In particular, we briefly review the opportunities for modelling psychophysiological phenomena such as sensory attenuation and related failures of gain control, of the sort seen in Parkinson's disease. We also consider the fundamental difference between active inference and optimal control formulations, showing that in the former the heavy lifting shifts from solving a dynamical inverse problem to creating deep forward or generative models with dynamics, whose attracting sets prescribe desired behaviours. PMID:27683002
Active inference and robot control: a case study.
Pio-Lopez, Léo; Nizard, Ange; Friston, Karl; Pezzulo, Giovanni
2016-09-01
Active inference is a general framework for perception and action that is gaining prominence in computational and systems neuroscience but is less known outside these fields. Here, we discuss a proof-of-principle implementation of the active inference scheme for the control or the 7-DoF arm of a (simulated) PR2 robot. By manipulating visual and proprioceptive noise levels, we show under which conditions robot control under the active inference scheme is accurate. Besides accurate control, our analysis of the internal system dynamics (e.g. the dynamics of the hidden states that are inferred during the inference) sheds light on key aspects of the framework such as the quintessentially multimodal nature of control and the differential roles of proprioception and vision. In the discussion, we consider the potential importance of being able to implement active inference in robots. In particular, we briefly review the opportunities for modelling psychophysiological phenomena such as sensory attenuation and related failures of gain control, of the sort seen in Parkinson's disease. We also consider the fundamental difference between active inference and optimal control formulations, showing that in the former the heavy lifting shifts from solving a dynamical inverse problem to creating deep forward or generative models with dynamics, whose attracting sets prescribe desired behaviours.
Harik, Georges
2010-01-01
We introduce a framework for representing a variety of interesting problems as inference over the execution of probabilistic model programs. We represent a "solution" to such a problem as a guide program which runs alongside the model program and influences the model program's random choices, leading the model program to sample from a different distribution than from its priors. Ideally the guide program influences the model program to sample from the posteriors given the evidence. We show how the KL- divergence between the true posterior distribution and the distribution induced by the guided model program can be efficiently estimated (up to an additive constant) by sampling multiple executions of the guided model program. In addition, we show how to use the guide program as a proposal distribution in importance sampling to statistically prove lower bounds on the probability of the evidence and on the probability of a hypothesis and the evidence. We can use the quotient of these two bounds as an estimate of ...
Energy Technology Data Exchange (ETDEWEB)
Chertkov, Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ahn, Sungsoo [Korea Advanced Inst. Science and Technology (KAIST), Daejeon (Korea, Republic of); Shin, Jinwoo [Korea Advanced Inst. Science and Technology (KAIST), Daejeon (Korea, Republic of)
2017-05-25
Computing partition function is the most important statistical inference task arising in applications of Graphical Models (GM). Since it is computationally intractable, approximate methods have been used to resolve the issue in practice, where meanfield (MF) and belief propagation (BP) are arguably the most popular and successful approaches of a variational type. In this paper, we propose two new variational schemes, coined Gauged-MF (G-MF) and Gauged-BP (G-BP), improving MF and BP, respectively. Both provide lower bounds for the partition function by utilizing the so-called gauge transformation which modifies factors of GM while keeping the partition function invariant. Moreover, we prove that both G-MF and G-BP are exact for GMs with a single loop of a special structure, even though the bare MF and BP perform badly in this case. Our extensive experiments, on complete GMs of relatively small size and on large GM (up-to 300 variables) confirm that the newly proposed algorithms outperform and generalize MF and BP.
Total Nuclear Reaction Cross Section Induced by Halo Nuclei and Stable Nuclei
Institute of Scientific and Technical Information of China (English)
GUO Wen-Jun; JIANG Huan-Qing; LIU Jian-Ye; ZUO Wei; REN Zhong-Zhou; LEE Xi-Guo
2003-01-01
We develop a method for calculation of the total reaction cross sections induced by the halo nuclei and stable. nuclei. This approach is based on the Glauber theory, which is valid for nuclear reactions at high energies. It is extended for nuclear reactions at low energies and intermediate energies by including both the quantum correction and Coulomb correction under the assumption of the effective nuclear density distribution. The calculated results of the total reaction cross section induced by stable nuclei agree well with 30 experimental data within 10 percent accuracy. The comparison between the numerical results and 20 experimental data for the total nuclear reaction cross section induced by the neutron halo nuclei and the proton halo nuclei indicates a satisfactory agreement after considering the halo structure of these nuclei, which implies quite different mean fields for the nuclear reactions induced by halo nuclei and stable nuclei. The halo nucleon distributions and the root-mean-square radii of these nuclei can be extracted from the above comparison based on the improved Glauber model, which indicates clearly the halo structures of these nuclei. Especially,it is clear to see that the medium correction of the nucleon-nucleon collision has little effect on the total reaction cross sections induced by the halo nuclei due to the very weak binding and the very extended density distribution.
Total Nuclear Reaction Cross Section Induced by Halo Nuclei and Stable Nuclei
Institute of Scientific and Technical Information of China (English)
GUOWen-Jun; JIANGHuan-Qing; LIUJian-Ye; ZUOWei; RENZhong-Zhou; LEEXi-Guo
2003-01-01
We develop a method for calculation of the total reaction cross sections induced by the halo nuclei and stable nuclei. This approach is based on the Glauber theory, which is valid for nuclear reactions at high energies. It is extended for nuclear reactions at low energies and intermediate energies by including both the quantum correction and Coulomb correction under the assumption of the effective nuclear density distribution. The calculated results of the total reaction cross section induced by stable nuclei agree well with 30 experimental data within 10 percent accuracy.The comparison between the numerical results and 20 experimental data for the total nuclear reaction cross section induced by the neutron halo nuclei and the proton halo nuclei indicates a satisfactory agreement after considering the halo structure of these nuclei, which implies quite digerent mean fields for the nuclear reactions induced by halo nuclei and stable nuclei. The halo nucleon distributions and the root-mean-square radii of these nuclei can be extracted from the above comparison based on the improved Glauber model, which indicates clearly the halo structures of these nuclei. Especially,it is clear to see that the medium correction of the nucleon-nucleon collision has little effect on the total reaction cross sections, induced by the halo nuclei due to the very weak binding and the very extended density distribution.
The star formation history of Seyfert 2 nuclei
Fernandes, R C; Melnick, Yu M; Terlevich, E; Terlevich, R J; Kunth, D; Lacerda, R R; Joguet, B
2004-01-01
We present a study of the stellar populations in the central ~ 200 pc of a large and homogeneous sample comprising 79 nearby galaxies, most of which are type 2 Seyferts. The star-formation history of these nuclei is reconstructed by means of state-of-the art population synthesis modeling of their spectra in the 3500--5200 A interval. A QSO-like featureless continuum (FC) is added to the models to account for possible scattered light from a hidden AGN. We find that: (1) The star-formation history of Seyfert 2 nuclei is remarkably heterogeneous: young starbursts, intermediate age, and old stellar populations all appear in significant and widely varying proportions. (2) A significant fraction of the nuclei show a strong FC component, but this FC is not always an indication of a hidden AGN: it can also betray the presence of a young, dusty starburst. (3) We detect weak broad Hbeta emission in several Seyfert 2s after cleaning the observed spectrum by subtracting the synthesis model. These are most likely the weak...
Statistical Inference and String Theory
Heckman, Jonathan J
2013-01-01
In this note we expose some surprising connections between string theory and statistical inference. We consider a large collective of agents sweeping out a family of nearby statistical models for an M-dimensional manifold of statistical fitting parameters. When the agents making nearby inferences align along a d-dimensional grid, we find that the pooled probability that the collective reaches a correct inference is the partition function of a non-linear sigma model in d dimensions. Stability under perturbations to the original inference scheme requires the agents of the collective to distribute along two dimensions. Conformal invariance of the sigma model corresponds to the condition of a stable inference scheme, directly leading to the Einstein field equations for classical gravity. By summing over all possible arrangements of the agents in the collective, we reach a string theory. We also use this perspective to quantify how much an observer can hope to learn about the internal geometry of a superstring com...
Fusion probability in heavy nuclei
Banerjee, Tathagata; Nath, S.; Pal, Santanu
2015-03-01
Background: Fusion between two massive nuclei is a very complex process and is characterized by three stages: (a) capture inside the potential barrier, (b) formation of an equilibrated compound nucleus (CN), and (c) statistical decay of the CN leading to a cold evaporation residue (ER) or fission. The second stage is the least understood of the three and is the most crucial in predicting yield of superheavy elements (SHE) formed in complete fusion reactions. Purpose: A systematic study of average fusion probability, PCN> , is undertaken to obtain a better understanding of its dependence on various reaction parameters. The study may also help to clearly demarcate onset of non-CN fission (NCNF), which causes fusion probability, PCN, to deviate from unity. Method: ER excitation functions for 52 reactions leading to CN in the mass region 170-220, which are available in the literature, have been compared with statistical model (SM) calculations. Capture cross sections have been obtained from a coupled-channels code. In the SM, shell corrections in both the level density and the fission barrier have been included. PCN> for these reactions has been extracted by comparing experimental and theoretical ER excitation functions in the energy range ˜5 %-35% above the potential barrier, where known effects of nuclear structure are insignificant. Results: PCN> has been shown to vary with entrance channel mass asymmetry, η (or charge product, ZpZt ), as well as with fissility of the CN, χCN. No parameter has been found to be adequate as a single scaling variable to determine PCN> . Approximate boundaries have been obtained from where PCN> starts deviating from unity. Conclusions: This study quite clearly reveals the limits of applicability of the SM in interpreting experimental observables from fusion reactions involving two massive nuclei. Deviation of PCN> from unity marks the beginning of the domain of dynamical models of fusion. Availability of precise ER cross sections
Accretion disc time lag distributions: applying CREAM to simulated AGN light curves
Starkey, D. A.; Horne, Keith; Villforth, C.
2016-02-01
Active galactic nuclei (AGN) vary in their brightness across all wavelengths. Moreover, longer wavelength ultraviolet-optical continuum light curves appear to be delayed with respect to shorter wavelength light curves. A simple way to model these delays is by assuming thermal reprocessing of a variable point source (a lamp post) by a blackbody accretion disc. We introduce a new method, CREAM (Continuum REprocessed AGN Markov Chain Monte Carlo), that models continuum variations using this lamp post model. The disc light curves lag the lamp post emission with a time delay distribution sensitive to the disc temperature-radius profile and inclination. We test CREAM's ability to recover both inclination and product of black hole mass and accretion rate {Mdot{M}}, and show that the code is also able to infer the shape of the driving light curve. CREAM is applied to synthetic light curves expected from 1000 s exposures of a 17th magnitude AGN with a 2-m telescope in Sloan g and i bands with Signal-to-Noise Ratio (SNR) of 500-900 depending on the filter and lunar phase. We also test CREAM on poorer quality g and i light curves with SNR = 100. We find in the high-SNR case that CREAM can recover the accretion disc inclination to within an uncertainty of 5° and an {Mdot{M}} to within 0.04 dex.
Active Inference and Learning in the Cerebellum.
Friston, Karl; Herreros, Ivan
2016-09-01
This letter offers a computational account of Pavlovian conditioning in the cerebellum based on active inference and predictive coding. Using eyeblink conditioning as a canonical paradigm, we formulate a minimal generative model that can account for spontaneous blinking, startle responses, and (delay or trace) conditioning. We then establish the face validity of the model using simulated responses to unconditioned and conditioned stimuli to reproduce the sorts of behavior that are observed empirically. The scheme's anatomical validity is then addressed by associating variables in the predictive coding scheme with nuclei and neuronal populations to match the (extrinsic and intrinsic) connectivity of the cerebellar (eyeblink conditioning) system. Finally, we try to establish predictive validity by reproducing selective failures of delay conditioning, trace conditioning, and extinction using (simulated and reversible) focal lesions. Although rather metaphorical, the ensuing scheme can account for a remarkable range of anatomical and neurophysiological aspects of cerebellar circuitry-and the specificity of lesion-deficit mappings that have been established experimentally. From a computational perspective, this work shows how conditioning or learning can be formulated in terms of minimizing variational free energy (or maximizing Bayesian model evidence) using exactly the same principles that underlie predictive coding in perception.
Chemical complexity in galactic nuclei
Martin-Pintado, Jesus
2007-12-01
In recent years our knowledge of the chemical complexity in the nuclei of galaxies has dramatically changed. Recent observations of the nucleus of the Milky Way, of the starburst galaxy NGC253 and of the ultraluminous infrared galaxy (ULIRG) Arp220 have shown large abundance of complex organic molecules believed to be formed on grains. The Galactic center appears to be the largest repository of complex organic molecule like aldehydes and alcohols in the galaxy. We also measure large abundance of methanol in starburst galaxies and in ULIRGs suggesting that complex organic molecules are also efficiently produced in the central region of galaxies with strong star formation activity. From the systematic observational studies of molecular abundance in regions dominated by different heating processes like shocks, UV radiation, X-rays and cosmic rays in the center of the Milky Way, we are opening the possibility of using chemistry as a diagnostic tool to study the highly obscured regions of galactic centers. The templates found in the nucleus of the Milky Way will be used to establish the main mechanisms driving the heating and the chemistry of the molecular clouds in galaxies with different type of activity. The role of grain chemistry in the chemical complexity observed in the center of galaxies will be also briefly discussed.
Molecular outflows in starburst nuclei
Roy, Arpita; Sharma, Prateek; Shchekinov, Yuri
2016-01-01
Recent observations have detected molecular outflows in a few nearby starburst nuclei. We discuss the physical processes at work in such an environment in order to outline a scenario that can explain the observed parameters of the phenomenon, such as the molecular mass, speed and size of the outflows. We show that outflows triggered by OB associations, with $N_{OB}\\ge 10^5$ (corresponding to a star formation rate (SFR)$\\ge 1$ M$_{\\odot}$ yr$^{-1}$ in the nuclear region), in a stratified disk with mid-plane density $n_0\\sim 200\\hbox{--}1000$ cm$^{-3}$ and scale height $z_0\\ge 200 (n_0/10^2 \\, {\\rm cm}^{-3})^{-3/5}$ pc, can form molecules in a cool dense and expanding shell. The associated molecular mass is $\\ge 10^7$ M$_\\odot$ at a distance of a few hundred pc, with a speed of several tens of km s$^{-1}$. We show that a SFR surface density of $10 \\le \\Sigma_{SFR} \\le 50$ M$_\\odot$ yr$^{-1}$ kpc$^{-2}$ favours the production of molecular outflows, consistent with observed values.
Alpha decay chains from superheavy nuclei
Samanta, C
2008-01-01
Magic islands for extra-stable nuclei in the midst of the sea of fission-instability were predicted to be around Z=114, 124 or, 126 with N=184, and Z=120, with N=172. Whether these fission-survived superheavy nuclei with high Z and N would live long enough for detection or, undergo alpha-decay in a very short time remains an open question. Alpha-decay half lives of nuclei with 130 118 are found to have alpha-decay half lives of the order of microseconds or, less.
Deep inelastic scattering on asymmetric nuclei
Saito, K.; Boros, C.; Tsushima, K.; Bissey, F.; Afnan, I. R.; Thomas, A. W.
2000-11-01
We study deep inelastic scattering on isospin asymmetric nuclei. In particular, the difference of the nuclear structure functions and the Gottfried sum rule for the lightest mirror nuclei, 3He and 3H, are investigated. It is found that such systems can provide significant information on charge symmetry breaking and flavor asymmetry in the nuclear medium. Furthermore, we propose a new method to extract the neutron structure function from radioactive isotopes far from the line of stability. We also discuss the flavor asymmetry in the Drell-Yan process with isospin asymmetric nuclei.
Coupled-cluster computations of atomic nuclei
Hagen, G; Hjorth-Jensen, M; Dean, D J
2013-01-01
In the past decade, coupled-cluster theory has seen a renaissance in nuclear physics, with computations of neutron-rich and medium-mass nuclei. The method is efficient for nuclei with product-state references, and it describes many aspects of weakly bound and unbound nuclei. This report reviews the technical and conceptual developments of this method in nuclear physics, and the results of coupled-cluster calculations for nucleonic matter, and for exotic isotopes of helium, oxygen, calcium, and some of their neighbors.
Optimization methods for logical inference
Chandru, Vijay
2011-01-01
Merging logic and mathematics in deductive inference-an innovative, cutting-edge approach. Optimization methods for logical inference? Absolutely, say Vijay Chandru and John Hooker, two major contributors to this rapidly expanding field. And even though ""solving logical inference problems with optimization methods may seem a bit like eating sauerkraut with chopsticks. . . it is the mathematical structure of a problem that determines whether an optimization model can help solve it, not the context in which the problem occurs."" Presenting powerful, proven optimization techniques for logic in
Response of cloud condensation nuclei (>50 nm) to changes in ion-nucleation
DEFF Research Database (Denmark)
Svensmark, Henrik; Enghoff, Martin Andreas Bødker; Pedersen, Jens Olaf Pepke
2013-01-01
In experiments where ultraviolet light produces aerosols from trace amounts of ozone, sulfur dioxide, and water vapor, the relative increase in aerosols produced by ionization by gamma sources is constant from nucleation to diameters larger than 50 nm, appropriate for cloud condensation nuclei. T...
Statistical inference via fiducial methods
Salomé, Diemer
1998-01-01
In this thesis the attention is restricted to inductive reasoning using a mathematical probability model. A statistical procedure prescribes, for every theoretically possible set of data, the inference about the unknown of interest. ... Zie: Summary
On principles of inductive inference
Kostecki, Ryszard Paweł
2011-01-01
We propose an intersubjective epistemic approach to foundations of probability theory and statistical inference, based on relative entropy and category theory, and aimed to bypass the mathematical and conceptual problems of existing foundational approaches.
Critical-Point Structure in Finite Nuclei
Leviatan, A
2006-01-01
Properties of quantum shape-phase transitions in finite nuclei are considered in the framework of the interacting boson model. Special emphasis is paid to the dynamics at the critical-point of a general first-order phase transition.
Few-Body Universality in Halo Nuclei
Directory of Open Access Journals (Sweden)
Hammer H.-W.
2016-01-01
Full Text Available Few-body systems with resonant S-wave interactions show universal properties which are independent of the interaction at short distances. These properties include a geometric spectrum of three- and higher-body bound states and universal correlations between few-body observables. They can be observed on a wide range of scales from hadrons and nuclei to ultracold atoms. In this contribution, we focus on few-body universality in halo nuclei which can be considered as effective few-body systems consisting of halo nucleons and a core. This concept provides a unifying framework for halo nuclei with calculable corrections. Recent progress in this field with an emphasis on the possibility of finding Efimov states in halo nuclei is discussed.
Few-Body Universality in Halo Nuclei
Hammer, H.-W.
2016-03-01
Few-body systems with resonant S-wave interactions show universal properties which are independent of the interaction at short distances. These properties include a geometric spectrum of three- and higher-body bound states and universal correlations between few-body observables. They can be observed on a wide range of scales from hadrons and nuclei to ultracold atoms. In this contribution, we focus on few-body universality in halo nuclei which can be considered as effective few-body systems consisting of halo nucleons and a core. This concept provides a unifying framework for halo nuclei with calculable corrections. Recent progress in this field with an emphasis on the possibility of finding Efimov states in halo nuclei is discussed.
GDR in Hot Nuclei: New Measurements
Camera, F.; Kmiecik, M.; Wieland, O.; Benzoni, G.; Bracco, A.; Brambilla, S.; Crespi, F.; Mason, P.; Moroni, A.; Million, B.; Leoni, S.; Maj, A.; Styczen, J.; Brekiesz, M.; Meczynski, W.; Zieblinski, M.; Gramegna, F.; Barlini, S.; Kravchuk, V. L.; Lanchais, A. L.; Mastinu, P. F.; Bruno, M.; D'Agostino, M.; Geraci, E.; Ordine, A.; Casini, G.; Chiari, M.
2005-04-01
The measured properties of the Giant Dipole Resonance in hot rotating nuclei are successfully described with the model of thermal fluctuations, even though there are still some open problems especially at very low (T 2.5MeV) temperatures and missing data in some mass regions. Recent experimental works have addressed more specific problems regarding the nuclear shape and its behaviour in very particular and delimited phase space regions. In this paper will be discussed new exclusive measurements of the GDR γ decay in heavy 216Rn nuclei (where the shape of nuclei surviving fission have been probed) and some preliminary data on the 132Ce nuclei at very high excitation energy.
On The Structure of A=3 Nuclei
Abbas, Syed Afsar
2011-01-01
The hole in the charge distribution of $^3{\\text He}$ is a major problem in A=3 nuclei. The canonical wavefucntion of A=3 nuclei which does well for electromagnetic properties of A=3 nuclei fails to produce the hole in A=3 nuclei. The hole is normally assumed to arise from explicit quark degree of freedom. Very often quark degrees of freedom are imposed to propose a different short range part of the wavefunction for A=3 to explain the hole in $^3{\\text He}$. So an hybrid model with nucleonic degree of freedom in outer part and quark degrees of freedom in the inner part of the nucleus have been invoked to understand the above problem. Here we present a different picture with a new wavefunction working at short range within nucleonic degrees of freedom itself. So the above problem is explained here based entirely on the nucleonic degree of freedom only.
Transient X-ray Emission from Normal Galactic Nuclei
Wong, A Y L; Cheng, K S
2007-01-01
X-ray transients appeared in optically non-active galactic nuclei have been observed in recent years. The most popular model explaining this kind of phenomena is the conventional tidal disruption model. In this model, when a star moves within the tidal radius of a black hole, part of the star materials will fall into the black hole through an accretion disk, which gives rise to the luminous flare. We propose that the X-ray emission may not necessarily come from radiation of the accretion disk. Instead, it may be related to a jet. As the jet travels in the interstellar medium, a shock is produced and synchrotron radiation is expected. We compared the model light curve and the synchrotron radiation spectrum with the observed data, and find that our model explains the observed light curve and late-time spectrum well. Our model predicts that these transient active galactic nuclei could be sources of the future gamma-ray satellites, e.g. GLAST and the emission region will be expanding with time.
Type Inference for Guarded Recursive Data Types
Stuckey, Peter J.; Sulzmann, Martin
2005-01-01
We consider type inference for guarded recursive data types (GRDTs) -- a recent generalization of algebraic data types. We reduce type inference for GRDTs to unification under a mixed prefix. Thus, we obtain efficient type inference. Inference is incomplete because the set of type constraints allowed to appear in the type system is only a subset of those type constraints generated by type inference. Hence, inference only succeeds if the program is sufficiently type annotated. We present refin...
Statistical Inference in Graphical Models
2008-06-17
Probabilistic Network Library ( PNL ). While not fully mature, PNL does provide the most commonly-used algorithms for inference and learning with the efficiency...of C++, and also offers interfaces for calling the library from MATLAB and R 1361. Notably, both BNT and PNL provide learning and inference algorithms...mature and has been used for research purposes for several years, it is written in MATLAB and thus is not suitable to be used in real-time settings. PNL
Implementing Deep Inference in Tom
Kahramanogullari, Ozan; Moreau, Pierre-Etienne; Reilles, Antoine
2005-01-01
ISSN 1430-211X; The calculus of structures is a proof theoretical formalism which generalizes sequent calculus with the feature of deep inference: in contrast to sequent calculus, the calculus of structures does not rely on the notion of main connective and, like in term rewriting, it permits the application of the inference rules at any depth inside a formula. Tom is a pattern matching processor that integrates term rewriting facilities into imperative languages. In this paper, relying on th...
An Inference Language for Imaging
DEFF Research Database (Denmark)
Pedemonte, Stefano; Catana, Ciprian; Van Leemput, Koen
2014-01-01
We introduce iLang, a language and software framework for probabilistic inference. The iLang framework enables the definition of directed and undirected probabilistic graphical models and the automated synthesis of high performance inference algorithms for imaging applications. The iLang framewor......-accelerated primitives specializes iLang to the spatial data-structures that arise in imaging applications. We illustrate the framework through a challenging application: spatio-temporal tomographic reconstruction with compressive sensing....
Bayesian Inference: with ecological applications
Link, William A.; Barker, Richard J.
2010-01-01
This text provides a mathematically rigorous yet accessible and engaging introduction to Bayesian inference with relevant examples that will be of interest to biologists working in the fields of ecology, wildlife management and environmental studies as well as students in advanced undergraduate statistics.. This text opens the door to Bayesian inference, taking advantage of modern computational efficiencies and easily accessible software to evaluate complex hierarchical models.
Statistical Inference: The Big Picture.
Kass, Robert E
2011-02-01
Statistics has moved beyond the frequentist-Bayesian controversies of the past. Where does this leave our ability to interpret results? I suggest that a philosophy compatible with statistical practice, labelled here statistical pragmatism, serves as a foundation for inference. Statistical pragmatism is inclusive and emphasizes the assumptions that connect statistical models with observed data. I argue that introductory courses often mis-characterize the process of statistical inference and I propose an alternative "big picture" depiction.
Synthesis of superheavy nuclei: Obstacles and opportunities
Directory of Open Access Journals (Sweden)
Zagrebaev V.I.
2015-01-01
Full Text Available There are only 3 methods for the production of heavy and superheavy (SH nuclei, namely, fusion reactions, a sequence of neutron capture and beta(- decay and multinucleon transfer reactions. Low values of the fusion cross sections and very short half-lives of nuclei with Z<120 put obstacles in synthesis of new elements. At the same time, an important area of SH isotopes located between those produced in the cold and hot fusion reactions remains unstudied yet. This gap could be filled in fusion reactions of 48Ca with available lighter isotopes of Pu, Am, and Cm. New neutron-enriched isotopes of SH elements may be produced with the use of a 48Ca beam if a 250Cm target would be prepared. In this case we get a real chance to reach the island of stability owing to a possible beta(+ decay of 291114 and 287112 nuclei formed in this reaction with a cross section of about 0.8 pb. A macroscopic amount of the long-living SH nuclei located at the island of stability may be produced by using the pulsed nuclear reactors of the next generation only if the neutron fluence per pulse will be increased by about three orders of magnitude. Multinucleon transfer processes look quite promising for the production and study of neutron-rich heavy nuclei located in upper part of the nuclear map not reachable by other reaction mechanisms. Reactions with actinide beams and targets are of special interest for synthesis of new neutron-enriched transfermium nuclei and not-yet-known nuclei with closed neutron shell N=126 having the largest impact on the astrophysical r-process. The estimated cross sections for the production of these nuclei allows one to plan such experiments at currently available accelerators.
Energy Technology Data Exchange (ETDEWEB)
Hartmann, T.; Volz, S.; Babilon, M.; Mohr, P.; Vogt, K.; Zilges, A
2003-05-19
Recently the importance of small contributions of electric dipole strength near the particle threshold to the production rates of atomic nuclei has become evident. Prior estimates concentrated on the Giant Dipole Resonance (GDR) which dominates photoabsorption in all nuclei. Extrapolations to smaller excitation energies were assumed to be sufficiently reliable. However, new measurements reveal that collective E1 strength can be found in the threshold region.
Statistical Properties of Quantum Spectra in Nuclei
Institute of Scientific and Technical Information of China (English)
2001-01-01
Some aspects of quantum chaos in a finite system have been studied based on the analysis of statistical behaviors of quantum spectrum in nuclei. The experiment data show the transition from order to chaos with increasing excitation energy in spherical nuclei. The dependence of the order to chaos transition on nuclear deformation and nuclear rotating is described. The influence of pairing effect on the order to chaos transition is also discussed. Some important experiment phenomena in nuclear
Shell structure of nuclei far from stability
Grawe, H
2001-01-01
The experimental status of shell structure studies in medium-heavy nuclei far off the line of beta-stability is reviewed. Experimental techniques, signatures for shell closure and expectations for future investigations are discussed for the key regions around sup 4 sup 8 sup , sup 5 sup 6 Ni, sup 1 sup 0 sup 0 Sn for proton rich nuclei and the neutron-rich N=20 isotones, Ca, Ni and Sn isotopes.
Masses of nuclei close to the dripline
Herfurth, F; Beck, D; Blaum, K; Bollen, G; Kellerbauer, A G; Kluge, H J; Lunney, M D; Rodríguez, D; Schwarz, S; Sikler, G; Weber, C
2003-01-01
Mass measurements of radioactive nuclides are one of the cornerstones of our understanding of the nucleus. The Penning trap spectrometer ISOLTRAP performs direct mass measurements far away from the valley of stability, as well as high-precision measurements of key nuclei to anchor long decay chains. Both schemes provide valuable information on the dripline itself and on nuclei in its close vicinity. (10 refs) .
Realistic level density calculation for heavy nuclei
Energy Technology Data Exchange (ETDEWEB)
Cerf, N. [Institut de Physique Nucleaire, Orsay (France); Pichon, B. [Observatoire de Paris, Meudon (France); Rayet, M.; Arnould, M. [Institut d`Astronomie et d`Astrophysique, Bruxelles (Belgium)
1994-12-31
A microscopic calculation of the level density is performed, based on a combinatorial evaluation using a realistic single-particle level scheme. This calculation relies on a fast Monte Carlo algorithm, allowing to consider heavy nuclei (i.e., large shell model spaces) which could not be treated previously in combinatorial approaches. An exhaustive comparison of the predicted neutron s-wave resonance spacings with experimental data for a wide range of nuclei is presented.
Quark Degrees of Freedom in Finite Nuclei
Tsushima, K; Thomas, A W; Tsushima, Kazuo; Saito, Koichi; Thomas, Anthony W.
1996-01-01
Properties of finite nuclei are investigated based on relativistic Hartree equations which have been derived from a relativistic quark model of the structure of bound nucleons. Nucleons are assumed to interact through the (self-consistent) exchange of scalar ($\\sigma$) and vector ($\\omega$ and and the rms charge radius in $^{40}$Ca. Calculated properties of static, closed-shell nuclei, as well as symmetric nuclear matter are compared with experimental data and with the results of Quantum Hadrodynamics (QHD).
Abductive inference and delusional belief.
Coltheart, Max; Menzies, Peter; Sutton, John
2010-01-01
Delusional beliefs have sometimes been considered as rational inferences from abnormal experiences. We explore this idea in more detail, making the following points. First, the abnormalities of cognition that initially prompt the entertaining of a delusional belief are not always conscious and since we prefer to restrict the term "experience" to consciousness we refer to "abnormal data" rather than "abnormal experience". Second, we argue that in relation to many delusions (we consider seven) one can clearly identify what the abnormal cognitive data are which prompted the delusion and what the neuropsychological impairment is which is responsible for the occurrence of these data; but one can equally clearly point to cases where this impairment is present but delusion is not. So the impairment is not sufficient for delusion to occur: a second cognitive impairment, one that affects the ability to evaluate beliefs, must also be present. Third (and this is the main thrust of our paper), we consider in detail what the nature of the inference is that leads from the abnormal data to the belief. This is not deductive inference and it is not inference by enumerative induction; it is abductive inference. We offer a Bayesian account of abductive inference and apply it to the explanation of delusional belief.
Active inference, communication and hermeneutics.
Friston, Karl J; Frith, Christopher D
2015-07-01
Hermeneutics refers to interpretation and translation of text (typically ancient scriptures) but also applies to verbal and non-verbal communication. In a psychological setting it nicely frames the problem of inferring the intended content of a communication. In this paper, we offer a solution to the problem of neural hermeneutics based upon active inference. In active inference, action fulfils predictions about how we will behave (e.g., predicting we will speak). Crucially, these predictions can be used to predict both self and others--during speaking and listening respectively. Active inference mandates the suppression of prediction errors by updating an internal model that generates predictions--both at fast timescales (through perceptual inference) and slower timescales (through perceptual learning). If two agents adopt the same model, then--in principle--they can predict each other and minimise their mutual prediction errors. Heuristically, this ensures they are singing from the same hymn sheet. This paper builds upon recent work on active inference and communication to illustrate perceptual learning using simulated birdsongs. Our focus here is the neural hermeneutics implicit in learning, where communication facilitates long-term changes in generative models that are trying to predict each other. In other words, communication induces perceptual learning and enables others to (literally) change our minds and vice versa. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.
Production and interaction of the eta meson with nucleons and nuclei
Krzemien, Wojciech; Moskal, Paweł; Ozyrianska-Schätti, Iryna; Rundel, Oleksandr; Skurzok, Magdalena
2016-01-01
We report on the status of the search for eta-mesic nuclei and the studies of the interaction of the eta meson with nucleons. Recently we have completed the analysis of the new WASA-at-COSY data on the production of the eta meson with polarized proton beam. New results on the analyzing power for the pp->ppeta reaction with more than an order of magnitude improved precision shed a new light on the production mechanism of the eta meson in nucleon-nucleon collisions. Also, the latest results of the search for eta-mesic nuclei are discussed.
Rauscher, T; Hirschi, R
2015-01-01
Nucleosynthesis of heavy elements requires the use of different experimental and theoretical methods to determine astrophysical reaction rates than light element nucleosynthesis. Additionally, there are also larger uncertainties involved in the astrophysical models, both because the sites are not well known and because of differing numerical treatments in different models. As an example for the latter, the production of p-nuclei is compared in two different stellar models, demonstrating that a model widely used for postproduction calculations may have a zone grid too coarse to follow the synthesis of p-nuclei in detail.
Hot nuclei in reactions induced by heavy projectiles, protons and antiprotons
Energy Technology Data Exchange (ETDEWEB)
Galin, J.
1995-12-31
Light projectiles like protons and antiprotons with several GeV kinetic energy enable a very efficient heating of nuclei, similar to what is routinely achieved in nucleus-nucleus collisions. At the same time, the excitation of the collective modes in nuclei is minimized, making possible for the first time the study of the heat effects exclusively. The scarcity of multifragmentation in antiproton induced reactions on heavy targets seems to show that when such a phenomenon occurs in a nucleus-nucleus collisions it is most likely driven by initial compression and angular momentum rather than heat. (author). 41 refs.
Production and interaction of the η meson with nucleons and nuclei
Directory of Open Access Journals (Sweden)
Krzemień Wojciech
2016-01-01
Full Text Available We report on the status of the search for η-mesic nuclei and the studies of the interaction of the η meson with nucleons. Recently we have completed the analysis of the newWASA-at-COSY data on the production of the η meson with polarized proton beam. New results on the analyzing power for the p̄p → ppη reaction with more than an order of magnitude improved precision shed a new light on the production mechanism of the η meson in nucleon-nucleon collisions. Also, the latest results of the search for η-mesic nuclei are discussed.
Accretion Disc Time Lag Distributions: Applying CREAM to Simulated AGN Light Curves
Starkey, David; Villforth, Carolin
2015-01-01
Active Galactic Nuclei (AGN) vary in their brightness across all wavelengths. Moreover, longer wavelength ultraviolet - optical continuum light curves appear to be delayed with respect to shorter wavelength light curves. A simple way to model these delays is by assuming thermal reprocessing of a variable point source (a lamp post) by a blackbody accretion disc. We introduce a new method, CREAM (\\textbf{C}ontinuum \\textbf{RE}processed \\textbf{A}GN \\textbf{M}arkov Chain Monte Carlo), that models continuum variations using this lamp post model. The disc light curves lag the lamp post emission with a time delay distribution sensitive to the disc temperature-radius profile and inclination. We test CREAM's ability to recover both inclination and product of black hole mass and accretion rate $\\mmdot$, and show that the code is also able to infer the shape of the driving light curve. CREAM is applied to synthetic light curves expected from 1000 second exposures of a 17th magnitude AGN with a 2m telescope in Sloan g a...
Strangeness in nuclei and neutron stars
Lonardoni, Diego
2017-01-01
The presence of exotic particles in the core of neutron stars (NS) has been questioned for a long time. At present, it is still an unsolved problem that drives intense research efforts, both theoretical and experimental. The appearance of strange baryons in the inner regions of a NS, where the density can exceed several times the nuclear saturation density, is likely to happen due to energetic considerations. The onset of strange degrees of freedom is considered as an effective mechanism to soften the equation of state (EoS). This softening affects the entire structure of the star, reducing the pressure and therefore the maximum mass that the star can stably support. The observation of two very massive NS with masses of the order of 2M⊙ seems instead to rule out soft EoS, apparently excluding the possibility of hyperon formation in the core of the star. This inconsistency, usually referred to as the hyperon puzzle, is based on what we currently know about the interaction between strange particles and normal nucleons. The combination of a poor knowledge of the hypernuclear interactions and the difficulty of obtaining clear astrophysical evidence of the presence of hyperons in NS makes the understanding of the behavior of strange degrees of freedom in NS an intriguing theoretical challenge. We give our contribution to the discussion by studying the general problem of the hyperon-nucleon interaction. We attack this issue by employing a quantum Monte Carlo (QMC) technique, that has proven to be successful in the description of strongly correlated Fermion systems, to the study of finite size nuclear systems including strange degrees of freedom, i.e. hypernuclei. We show that many-body hypernuclear forces are fundamental to properly reproduce the ground state physics of Λ hypernuclei from light- to medium-heavy. However, the poor abundance of experimental data on strange nuclei leaves room for a good deal of indetermination in the construction of hypernuclear
Structural and decay properties of $Z=132,138$ superheavy nuclei
Rather, Asloob A; Usmani, A A; Kumar, Bharat; Patra, S K
2016-01-01
In this paper, we analyze the structural properties of $Z=132$ and $Z=138$ superheavy nuclei within the ambit of axially deformed relativistic mean-field framework with NL$3^{*}$ parametrization and calculate the total binding energies, radii, quadrupole deformation parameter, separation energies, density distributions. We also investigate the phenomenon of shape coexistence by performing the calculations for prolate, oblate and spherical configurations. For clear presentation of nucleon distributions, the two-dimensional contour representation of individual nucleon density and total matter density has been made. Further, a competition between possible decay modes such as $\\alpha$-decay, $\\beta$-decay and spontaneous fission of the isotopic chain of superheavy nuclei with $Z=132$ within the range 312 $\\le$ A $\\le$ 392 and 318 $\\le$ A $\\le$ 398 for $Z=138$ is systematically analyzed within self-consistent relativistic mean field model. From our analysis, we inferred that the $\\alpha$-decay and spontaneous fiss...
An Inference Language for Imaging
DEFF Research Database (Denmark)
Pedemonte, Stefano; Catana, Ciprian; Van Leemput, Koen
2014-01-01
We introduce iLang, a language and software framework for probabilistic inference. The iLang framework enables the definition of directed and undirected probabilistic graphical models and the automated synthesis of high performance inference algorithms for imaging applications. The iLang framework...... is composed of a set of language primitives and of an inference engine based on a message-passing system that integrates cutting-edge computational tools, including proximal algorithms and high performance Hamiltonian Markov Chain Monte Carlo techniques. A set of domain-specific highly optimized GPU......-accelerated primitives specializes iLang to the spatial data-structures that arise in imaging applications. We illustrate the framework through a challenging application: spatio-temporal tomographic reconstruction with compressive sensing....
Locative inferences in medical texts.
Mayer, P S; Bailey, G H; Mayer, R J; Hillis, A; Dvoracek, J E
1987-06-01
Medical research relies on epidemiological studies conducted on a large set of clinical records that have been collected from physicians recording individual patient observations. These clinical records are recorded for the purpose of individual care of the patient with little consideration for their use by a biostatistician interested in studying a disease over a large population. Natural language processing of clinical records for epidemiological studies must deal with temporal, locative, and conceptual issues. This makes text understanding and data extraction of clinical records an excellent area for applied research. While much has been done in making temporal or conceptual inferences in medical texts, parallel work in locative inferences has not been done. This paper examines the locative inferences as well as the integration of temporal, locative, and conceptual issues in the clinical record understanding domain by presenting an application that utilizes two key concepts in its parsing strategy--a knowledge-based parsing strategy and a minimal lexicon.
Sick, the spectroscopic inference crank
Casey, Andrew R
2016-01-01
There exists an inordinate amount of spectral data in both public and private astronomical archives which remain severely under-utilised. The lack of reliable open-source tools for analysing large volumes of spectra contributes to this situation, which is poised to worsen as large surveys successively release orders of magnitude more spectra. In this Article I introduce sick, the spectroscopic inference crank, a flexible and fast Bayesian tool for inferring astrophysical parameters from spectra. sick can be used to provide a nearest-neighbour estimate of model parameters, a numerically optimised point estimate, or full Markov Chain Monte Carlo sampling of the posterior probability distributions. This generality empowers any astronomer to capitalise on the plethora of published synthetic and observed spectra, and make precise inferences for a host of astrophysical (and nuisance) quantities. Model intensities can be reliably approximated from existing grids of synthetic or observed spectra using linear multi-di...
Electron scattering and reactions from exotic nuclei
Energy Technology Data Exchange (ETDEWEB)
Karataglidis, S. [University of Johannesburg, Department of Physics, Auckland Park (South Africa); University of Melbourne, School of Physics, Victoria (Australia)
2017-04-15
The SCRIT and FAIR/ELISe experiments are the first to attempt to measure directly electron scattering form factors from nuclei far from stability. This will give direct information for the (one-body) charge densities of those systems, about which there is little information available. The SCRIT experiment will be taking data for medium-mass exotic nuclei, while the electron-ion collider at ELISe, when constructed, will be able to measure form factors for a wide range of exotic nuclei, as available from the radioactive ion beams produced by the FAIR experiment. Other facilities are now being proposed, which will also consider electron scattering from exotic nuclei at higher energies, to study short-range correlations in exclusive reactions. This review will consider all available information concerning the current status (largely theoretical) of electron scattering from exotic nuclei and, where possible, complement such information with equivalent information concerning the neutron densities of those exotic systems, as obtained from intermediate energy proton scattering. The issue of long- and short-range correlations will be discussed, and whether extending such studies to the exotic sector will elicit new information. (orig.)
Pollen grains are efficient cloud condensation nuclei
Energy Technology Data Exchange (ETDEWEB)
Pope, F D, E-mail: fdp21@cam.ac.uk [Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW (United Kingdom)
2010-10-15
This letter presents a laboratory study investigating the ability of pollen grains to act as cloud condensation nuclei. The hygroscopicity of pollen is measured under subsaturated relative humidities using an electrodynamic balance. It is found, along with other results, that pollen exhibits bulk uptake of water under subsaturated conditions. Through the use of an environmental scanning electron microscope it was observed that the surface of pollen is wettable at high subsaturated humidities. The hygroscopic response of the pollen to subsaturated relative humidities is parametrized using {kappa}-Koehler theory and values of the parameter {kappa} for pollen are between 0.05 and 0.1. It is found that while pollen grains are only moderately hygroscopic, they can activate at critical supersaturations of 0.001% and lower, and thus pollen grains will readily act as cloud condensation nuclei. While the number density of pollen grains is too low for them to represent a significant global source of cloud condensation nuclei, the large sizes of pollen grains suggest that they will be an important source of giant cloud condensation nuclei. Low temperature work using the environmental scanning electron microscope indicated that pollen grains do not act as deposition ice nuclei at temperatures warmer than - 15 deg. C.
First experimental detection of antiproton in-flight annihilation on nuclei at 130 keV
Aghai-Khozani, H; Corradini, M; Hayano, R; Hori, M; Kobayashi, T; Leali, M; Lodi-Rizzini, E; Mascagna, V; Prest, M; Soter, A; Todoroki, K; Vallazza, E; Venturelli, L; Zurlo, N
2012-01-01
The existing data of antinucleon-nucleon and antinucleon-nuclei annihilation cross-sections are confined to energies above about 1MeV. Experimental limitations have prevented till now the lower energies data to be achieved in spite of the interest they represent for theoretical models. One of the unresolved question concerns the antiproton annihilation cross-section measured at LEAR on light nuclei in the MeV region, which show a saturation with the mass number of the target nucleus against any naive expectation. With regard to fundamental cosmology, the knowledge of the annihilation cross-sections at energies below 1MeV can contribute to understand the matter-antimatter asymmetry in the Universe. We present here the experimental demonstration of the feasibility of the measurement of antiproton-nuclei annihilation cross-sections in the 100 keV region.
Effects of Λ hyperon on localization and clustering in p- and sd-shell nuclei
Energy Technology Data Exchange (ETDEWEB)
Xu, Renli, E-mail: xurenli.phy@gmail.com [Key Laboratory of Modern Acoustics, Department of Physics, Nanjing University, Nanjing 210093 (China); Wu, Chen, E-mail: wuchenoffd@gmail.com [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Ren, Zhongzhou, E-mail: zren@nju.edu.cn [Key Laboratory of Modern Acoustics, Department of Physics, Nanjing University, Nanjing 210093 (China); Center of Theoretical Nuclear Physics, National Laboratory of Heavy-Ion Accelerator, Lanzhou 730000 (China); Joint Center of Nuclear Science and Technology, Nanjing University, Nanjing 210093 (China)
2015-01-15
In the present work, the properties of several deformed p- and sd-shell Λ-hypernuclei have been investigated using the self-consistent relativistic mean field theory. The calculated ground state energies are consistent with the experimental values. In particular, the possibility of localization and clustering in deformed nuclei is discussed, concentrating on experimentally accessible light nuclei. Utilizing the framework of relativistic mean field model, our calculation predicts formation of clusterlike structure in the ground state of {sup 28}Si and {sup 32}S, while the core nuclei in {sup 29}{sub Λ}Si and {sup 33}{sub Λ}S show a delocalized formation in the presence hyperon depending on the nuclear effective interaction.
Fusion and Direct Reactions of Halo Nuclei at Energies around the Coulomb Barrier
Keeley, N; Raabe, R; Sida, J L
2007-01-01
The present understanding of reaction processes involving light unstable nuclei at energies around the Coulomb barrier is reviewed. The effect of coupling to direct reaction channels on elastic scattering and fusion is investigated, with the focus on halo nuclei. A list of definitions of processes is given, followed by a review of the experimental and theoretical tools and information presently available. The effect of couplings on elastic scattering and fusion is studied with a series of model calculations within the coupled-channels framework. The experimental data on fusion are compared to "bare" no-coupling one-dimensional barrier penetration model calculations. On the basis of these calculations and comparisons with experimental data, conclusions are drawn from the observation of recurring features. The total fusion cross sections for halo nuclei show a suppression with respect to the "bare" calculations at energies just above the barrier that is probably due to single neutron transfer reactions. The dat...
Evidence of Critical Behavior in the Disassembly of Nuclei with A ~ 36
Ma, Y G; Hagel, K; Wang, J; Keutgen, T; Majka, Z; Murray, M; Qin, L; Smith, P; Natowitz, J B; Alfaro, R; Cibor, J; Cinausero, M; Masri, Y E; Fabris, D; Fioretto, E; Keksis, A L; Lunardon, M; Makeev, A G; Marie, N; Martin, E; Martínez-Davalos, A; Menchaca-Rocha, A; Nebbia, G; Prete, G; Rizzi, V; Ruangma, A; Shetty, D V; Souliotis, G A; Staszel, P; Veselsky, M; Viesti, G; Winchester, E M; Yennello, S J
2004-01-01
A wide variety of observables indicate that maximal fluctuations in the disassembly of hot nuclei with A ~ 36 occur at an excitation energy of 5.6 +- 0.5 MeV/u and temperature of 8.3 +- 0.5 MeV. Associated with this point of maximal fluctuations are a number of quantitative indicators of apparent critical behavior. The associated caloric curve does not appear to show a plateau such as that seen for heavier systems. This suggests that, in contrast to similar signals seen for apparent first order liquid-gas transitions in heavier nuclei, the observed behavior in these very light nuclei is associated with a transition much closer to the critical point.
Emergent properties of nuclei from ab initio coupled-cluster calculations
Hagen, G; Hjorth-Jensen, M; Papenbrock, T
2016-01-01
Emergent properties such as nuclear saturation and deformation, and the effects on shell structure due to the proximity of the scattering continuum and particle decay channels are fascinating phenomena in atomic nuclei. In recent years, ab initio approaches to nuclei have taken the first steps towards tackling the computational challenge of describing these phenomena from Hamiltonians with microscopic degrees of freedom. This endeavor is now possible due to ideas from effective field theories, novel optimization strategies for nuclear interactions, ab initio methods exhibiting a soft scaling with mass number, and ever-increasing computational power. This paper reviews some of the recent accomplishments. We also present new results. The recently optimized chiral interaction NNLO$_{\\rm sat}$ is shown to provide an accurate description of both charge radii and binding energies in selected light- and medium-mass nuclei up to $^{56}$Ni. We derive an efficient scheme for including continuum effects in coupled-clust...
Ebert, Eric; Kröger, Willfried; Damaschke, Nils
2015-12-01
Small particles, especially bubbles in the micro-meter range, influence the cavitation of the propellers. The prediction of cavitation inception and water quality measurements are important in cavitation research. The Hydrodynamic Nuclei Concentration (HDNC) technique can be used for reliable bubble concentration measurements in fluid flows. The HDNC technique bases on the analysis of scattered light from the cavitation nuclei in the water. The HDNC technique can distinguish between bubbles and solid particles. The particle type classification is important, because the number concentration of solid particles is often much higher than the nuclei concentration in cavitation tunnels and in seawater. Verification experiments show, that the HDNC technique reaches similar capabilities in number concentration estimation as Phase Doppler (PD) technique in much shorter acquisition time.
A statistical approach to describe highly excited heavy and superheavy nuclei
Chen, Peng-Hui; Feng, Zhao-Qing; Li, Jun-Qing; Zhang, Hong-Fei
2016-09-01
A statistical approach based on the Weisskopf evaporation theory has been developed to describe the de-excitation process of highly excited heavy and superheavy nuclei, in particular for the proton-rich nuclei. The excited nucleus is cooled by evaporating γ-rays, light particles (neutrons, protons, α etc) in competition with binary fission, in which the structure effects (shell correction, fission barrier, particle separation energy) contribute to the processes. The formation of residual nuclei is evaluated via sequential emission of possible particles above the separation energies. The available data of fusion-evaporation excitation functions in the 28Si+198Pt reaction can be reproduced nicely within the approach. Supported by Major State Basic Research Development Program in China (2015CB856903), National Natural Science Foundation of China Projects (11175218, U1332207, 11475050, 11175074), and Youth Innovation Promotion Association of Chinese Academy of Sciences
High spin spectroscopy of near spherical nuclei: Role of intruder orbitals
Energy Technology Data Exchange (ETDEWEB)
Bhattacharyya, S.; Bhattacharjee, T.; Mukherjee, G. [Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata - 700064 (India); Chanda, S. [Fakir Chand College, Diamond Herbour, West Bengal (India); Banerjee, D.; Das, S. K.; Guin, R. [Radiochemistry Division, Variable Energy Cyclotron Centre, BARC, Kolkata - 700064 (India); Gupta, S. Das [Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata - 700064, India and Saha Institute of Nuclear Physics, Kolkata-700064 (India); Pai, H. [Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata - 700064, India and Institut für Kernphysik, Technische Universität Darmstadt, Schlossgartenstrasse 9, 64289 Darmstadt (Germany)
2014-08-14
High spin states of nuclei in the vicinity of neutron shell closure N = 82 and proton shell closure Z = 82 have been studied using the Clovere Ge detectors of Indian National Gamma Array. The shape driving effects of proton and neutron unique parity intruder orbitals for the structure of nuclei around the above shell closures have been investigated using light and heavy ion beams. Lifetime measurements of excited states in {sup 139}Pr have been done using pulsed-beam-γ coincidence technique. The prompt spectroscopy of {sup 207}Rn has been extended beyond the 181μs 13/2{sup +} isomer. Neutron-rich nuclei around {sup 132}Sn have been produced from proton induced fission of {sup 235}U and lifetime measurement of low-lying states of odd-odd {sup 132}I have been performed from offline decay.
Eight challenges in phylodynamic inference
Directory of Open Access Journals (Sweden)
Simon D.W. Frost
2015-03-01
Full Text Available The field of phylodynamics, which attempts to enhance our understanding of infectious disease dynamics using pathogen phylogenies, has made great strides in the past decade. Basic epidemiological and evolutionary models are now well characterized with inferential frameworks in place. However, significant challenges remain in extending phylodynamic inference to more complex systems. These challenges include accounting for evolutionary complexities such as changing mutation rates, selection, reassortment, and recombination, as well as epidemiological complexities such as stochastic population dynamics, host population structure, and different patterns at the within-host and between-host scales. An additional challenge exists in making efficient inferences from an ever increasing corpus of sequence data.
Automatic Inference of DATR Theories
Barg, P
1996-01-01
This paper presents an approach for the automatic acquisition of linguistic knowledge from unstructured data. The acquired knowledge is represented in the lexical knowledge representation language DATR. A set of transformation rules that establish inheritance relationships and a default-inference algorithm make up the basis components of the system. Since the overall approach is not restricted to a special domain, the heuristic inference strategy uses criteria to evaluate the quality of a DATR theory, where different domains may require different criteria. The system is applied to the linguistic learning task of German noun inflection.
Object-Oriented Type Inference
DEFF Research Database (Denmark)
Schwartzbach, Michael Ignatieff; Palsberg, Jens
1991-01-01
We present a new approach to inferring types in untyped object-oriented programs with inheritance, assignments, and late binding. It guarantees that all messages are understood, annotates the program with type information, allows polymorphic methods, and can be used as the basis of an op-timizing......We present a new approach to inferring types in untyped object-oriented programs with inheritance, assignments, and late binding. It guarantees that all messages are understood, annotates the program with type information, allows polymorphic methods, and can be used as the basis of an op...
Reflections on cavitation nuclei in water
DEFF Research Database (Denmark)
Mørch, Knud Aage
2007-01-01
The origin of cavitation bubbles, cavitation nuclei, has been a subject of debate since the early years of cavitation research. This paper presents an analysis of a representative selection of experimental investigations of cavitation inception and the tensile strength of water. At atmospheric...... on the surface of particles and bounding walls. Such nuclei can be related to the full range of tensile strengths measured, when differences of experimental conditions are taken into consideration. The absence or presence of contamination on surfaces, as well as the structure of the surfaces, are central...... to explaining why the tensile strength of water varies so dramatically between the experiments reported. A model for calculation of the critical pressure of skin-covered free gas bubbles as well as that of interfacial gaseous nuclei covered by a skin is presented. This model is able to bridge the apparently...
Reflections on cavitation nuclei in water
DEFF Research Database (Denmark)
Mørch, Knud Aage
2007-01-01
The origin of cavitation bubbles, cavitation nuclei, has been a subject of debate since the early years of cavitation research. This paper presents an analysis of a representative selection of experimental investigations of cavitation inception and the tensile strength of water. At atmospheric...... to explaining why the tensile strength of water varies so dramatically between the experiments reported. A model for calculation of the critical pressure of skin-covered free gas bubbles as well as that of interfacial gaseous nuclei covered by a skin is presented. This model is able to bridge the apparently...... pressure, the possibility of stabilization of free gas bubbles by a skin has been documented, but only within a range of bubble sizes that makes them responsible for tensile strengths up to about 1.5 bar, and values reaching almost 300 bar have been measured. However, cavitation nuclei can also be harbored...
Alpha-cluster model of atomic nuclei
Energy Technology Data Exchange (ETDEWEB)
Sosin, Zbigniew; Kallunkathariyil, Jinesh [Jagiellonian University, M. Smoluchowski Institute of Physics, Krakow (Poland); Blocki, Jan [NCBJ, Theoretical Physics Division (BP2), Swierk (Poland); Lukasik, Jerzy; Pawlowski, Piotr [IFJ PAN, Krakow (Poland)
2016-05-15
The description of a nuclear system in its ground state and at low excitations based on the equation of state (EoS) around normal density is presented. In the expansion of the EoS around the saturation point, additional spin polarization terms are taken into account. These terms, together with the standard symmetry term, are responsible for the appearance of the α-like clusters in the ground-state configurations of the N=Z even-even nuclei. At the nuclear surface these clusters can be identified as alpha particles. A correction for the surface effects is introduced for atomic nuclei. Taking into account an additional interaction between clusters the binding energies and sizes of the considered nuclei are very accurately described. The limits of the EoS parameters are established from the properties of the α, {sup 3}He and t particles. (orig.)
Shape phase mixing in critical point nuclei
Budaca, R
2016-01-01
Spectral properties of nuclei near the critical point of the quantum phase transition between spherical and axially symmetric shapes are studied in a hybrid collective model which combines the $\\gamma$-stable and $\\gamma$-rigid collective conditions through a rigidity parameter. The model in the lower and upper limits of the rigidity parameter recovers the X(5) and X(3) solutions respectively, while in the equally mixed case it corresponds to the X(4) critical point symmetry. Numerical applications of the model on nuclei from regions known for critical behavior reveal a sizable shape phase mixing and its evolution with neutron or proton numbers. The model also enables a better description of energy spectra and electromagnetic transitions for these nuclei.
Statistical ensembles and fragmentation of finite nuclei
Das, P.; Mallik, S.; Chaudhuri, G.
2017-09-01
Statistical models based on different ensembles are very commonly used to describe the nuclear multifragmentation reaction in heavy ion collisions at intermediate energies. Canonical model results are more appropriate for finite nuclei calculations while those obtained from the grand canonical ones are more easily calculable. A transformation relation has been worked out for converting results of finite nuclei from grand canonical to canonical and vice versa. The formula shows that, irrespective of the particle number fluctuation in the grand canonical ensemble, exact canonical results can be recovered for observables varying linearly or quadratically with the number of particles. This result is of great significance since the baryon and charge conservation constraints can make the exact canonical calculations extremely difficult in general. This concept developed in this work can be extended in future for transformation to ensembles where analytical solutions do not exist. The applicability of certain equations (isoscaling, etc.) in the regime of finite nuclei can also be tested using this transformation relation.
Chao, Guo-Shan; Sung, Kung-Bin
2010-02-01
Backscattered light spectra have been used to extract size distribution of cell nuclei in epithelial tissues for noninvasive detection of precancerous lesions. In existing experimental studies, size estimation is achieved by assuming nuclei as homogeneous spheres or spheroids and fitting the measured data with models based on Mie theory. However, the validity of simplifying nuclei as homogeneous spheres has not been thoroughly examined. In this study, we investigate the spectral characteristics of backscattering from models of spheroidal nuclei under plane wave illumination using three-dimensional finite-difference time-domain (FDTD) simulation. A modulated Gaussian pulse is used to obtain wavelength dependent scattering intensity with a single FDTD run. The simulated model of nuclei consists of a nucleolus and randomly distributed chromatin condensation in homogeneous cytoplasm and nucleoplasm. The results show that backscattering spectra from spheroidal nuclei have similar oscillating patterns to those from homogeneous spheres with the diameter equal to the projective length of the spheroidal nucleus along the propagation direction. The strength of backscattering is enhanced in heterogeneous spheroids as compared to homogeneous spheroids. The degree of which backscattering spectra of heterogeneous nuclei deviate from Mie theory is highly dependent on the distribution of chromatin/nucleolus but not sensitive to nucleolar size, refractive index fluctuation or chromatin density.
Influence of orientation degree of freedom on fission dynamics of higly excited nuclei
Directory of Open Access Journals (Sweden)
Nadtochy P.N.
2013-12-01
Full Text Available Four-dimensional dynamical model was developed and employed for study fission characteristics in a wide range of fissility parameter. The three collective shape coordinates plus the K coordinate, which is the spin of the nucleus with respect to the symmetry (fission axis, were considered dynamically from the ground state deformation till the scission into fission fragments. A modified one-body mechanism for nuclear dissipation with a reduction coefficient ks of the contribution from a “wall” formula have been used in the study. The four-dimensional calculations for heavy nuclei could describe the fission fragment mass-energy distribution (MED parameters and prescission neutron multiplicity with almost single ks value, in contrast with 3D dynamical calculations, where a consistent description of all observables with the same ks is not possible for heavy nuclei. The estimation of a dissipation coefficient for the orientation degree of freedom γK = 0.077(MeV zs−1/2 is good for heavy nuclei and lower value of γK = 0.05(MeV zs−1/2 is needed for nuclei with mass A ≃ 200. The results of 4D and 3D Langevin dynamical calculations for light nuclei near the Businaro-Gallone point predict close results for the fission fragment MED parameters and prescission particles multiplicities.
The fate of ultrahigh energy nuclei in the immediate environment of young fast-rotating pulsars
Kotera, Kumiko; Blasi, Pasquale
2015-01-01
Young, fast-rotating neutron stars are promising candidate sources for the production of ultrahigh energy cosmic rays (UHECRs). The interest in this model has recently been boosted by the latest chemical composition measurements of cosmic rays, that seem to show the presence of a heavy nuclear component at the highest energies. Neutrons stars, with their metal-rich surfaces, are potentially interesting sources of such nuclei, but some open issues remain: 1) is it possible to extract these nuclei from the star's surface? 2) Do the nuclei survive the severe conditions present in the magnetosphere of the neutron star? 3) What happens to the surviving nuclei once they enter the wind that is launched outside the light cylinder? In this paper we address these issues in a quantitative way, proving that for the most reasonable range of neutron star surface temperatures ($T<10^7\\,$K), a large fraction of heavy nuclei survive photo-disintegration losses. These processes, together with curvature losses and accelerati...
Statistical properties of quantum spectra in nuclei
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
Some aspects of quantum chaos in a finite system have been studied based on the analysis of statistical behavior of quantum spectra in nuclei.The experiment data show the transition from order to chaos with increasing excitation energy in spherical nuclei.The dependence of the order to chaos transition on nuclear deformation and nuclear rotating is described.The influence of pairing effect on the order to chaos transition is also discussed.Some important experiment phenomena in nuclear physics have been understood from the point of view of the interplay between order and chaos.
Doubly magic properties in superheavy nuclei
Institute of Scientific and Technical Information of China (English)
HUANG Ya-Wei; ZHU Jian-Yu
2009-01-01
A systematic study of global properties of superheavy nuclei in the framework of the Liquid Drop Model and the Strutinsky shell correction method is performed. The evolution equilibrium deformations, TRS graphs and α-decay energies are calculated using the TRS model. The analysis covers a wide range of even-even superheavy nuclei from Z = 102 to 122. Magic numbers and their observable influence occurring in this region have been investigated. Shell closures appear at proton number Z = 114 and at neutron number N = 184.
Computer Model Of Fragmentation Of Atomic Nuclei
Wilson, John W.; Townsend, Lawrence W.; Tripathi, Ram K.; Norbury, John W.; KHAN FERDOUS; Badavi, Francis F.
1995-01-01
High Charge and Energy Semiempirical Nuclear Fragmentation Model (HZEFRG1) computer program developed to be computationally efficient, user-friendly, physics-based program for generating data bases on fragmentation of atomic nuclei. Data bases generated used in calculations pertaining to such radiation-transport applications as shielding against radiation in outer space, radiation dosimetry in outer space, cancer therapy in laboratories with beams of heavy ions, and simulation studies for designing detectors for experiments in nuclear physics. Provides cross sections for production of individual elements and isotopes in breakups of high-energy heavy ions by combined nuclear and Coulomb fields of interacting nuclei. Written in ANSI FORTRAN 77.
Medium energy hadron scattering from nuclei
Energy Technology Data Exchange (ETDEWEB)
Ginocchio, J.N.; Wenes, G.
1986-01-01
The Glauber approximation for medium energy scattering of hadronic projectiles from nuclei is combined with the interacting boson model of nuclei to produce a transition matrix for elastic and inelastic scattering in algebraic form which includes coupling to all the intermediate states. We present closed form analytic expresions for the transition matrix elements for the three dynamical symmetries of the interacting boson model; that is for, a spherical quadrupole vibrator, a ..gamma.. unstable rotor, and both prolate and oblate axially symmetric rotors. We give examples of application of this formalism to proton scattering from /sup 154/Sm and /sup 154/Gd. 27 refs., 5 figs., 1 tab.
Ultrahigh Energy Nuclei Propagation in a Structured, Magnetized Universe
Armengaud, E; Miniati, F; Armengaud, Eric; Sigl, Guenter; Miniati, Francesco
2004-01-01
We compare the propagation of iron and proton nuclei above 10^19 eV in a structured Universe with source and magnetic field distributions obtained from a large scale structure simulation and source densities about 10^(-5) Mpc^(-3). All relevant cosmic ray interactions are taken into account, including photo-disintegration and propagation of secondary products. Iron injection predicts spectral shapes different from proton injection which disagree with existing data below about 30 EeV. Injection of light nuclei or protons must therefore contribute at these energies. However, at higher energies, existing data are consistent with injection of pure iron with spectral indices between 2 and 2.4. This allows a significant recovery of the spectrum above roughly 100 EeV, especially in the case of large deflections. Significant auto-correlation and anisotropy, and considerable cosmic variance are also predicted in this energy range. The mean atomic mass A fluctuates considerably between different scenarios. At energies ...
Soft Dipole Modes of Neutron-Rich Nuclei
Csoto, A.; Gibson, B. F.; Afnan, I. R.
1996-10-01
We explore the open question of whether valance neutrons in ``halo nuclei'' can oscillate against the core to create a ``soft dipole'' mode. It has been suggested that such a dipole state would be situated at a few MeV of excitation energy, in contrast to usual dipole excitations at higher energies. The existence of a soft dipole mode, at least in ^11Li, appears to be supported by certain theoretical models and experimental data.footnote A. C. Hayes, Comments in Nuclear and Particle Physics 22, 27 (1996) However, this conclusion is based upon the behavior of specific observables at real energies. To clearly establish the existence of such resonant states, one should locate the corresponding complex poles of the S-matrix. We study ^6He and ^11Li in a three-body model based upon separable potentials that describe the known physics of the underlying two-body interactions. We solve the resulting Faddeev equations, continued into the complex energy plane, to search for the low lying excited states of these neutron-rich light nuclei.
Low-energy Antikaon Interaction with Nuclei: The AMADEUS Challenge
Marton, Johann; Bellotti, Giovanni; Berucci, Carolina; Bosnar, Dimitri; Bragadireanu, Mario; Curceanu, Catalina; Clozza, Alberto; Cargnelli, Michael; Butt, Aslan; Del Grande, Raffaele; Fabbietti, Laura; Fiorini, Carlo; Ghio, Francesco; Guaraldo, Carlo; Iliescu, Mihai; Sandri, Paolo Levi; Pietreanu, Dorel; Piscicchia, Kristian; Vidal, Antonio Romero; Scordo, Alessandro; Shi, Hexi; Sirghi, Diana; Sirghi, Florin; Tucakovic, Ivana; Doce, Oton Vazquez; Widmann, Eberhard; Zmeskal, Johann
2016-01-01
The low-energy strong interaction of antikaons (K-) with nuclei has many facets and rep- resents a lively and challenging research ?eld. It is interconnected to the peculiar role of strangeness, since the strange quark is rather light, but still much heavier than the up and down quarks. Thus, when strangeness is involved one has to deal with spontaneous and explicit symmetry breaking in QCD. It is well known that the antikaon interaction with nucleons is attractive, but how strong ? Is the interaction strong enough to bind nucleons to form kaonic nuclei and, if so, what are the properties (binding energy, decay width)? There are controversial indications for such bound states and new results are expected to come soon. The existence of antikaon mediated bound states might have important consequences since it would open the possibility for the formation of cold baryonic matter of high density which might have a severe impact in astrophysics for the understanding of the composi- tion of compact (neutron) stars. ...
Relativistic continuum random phase approximation in spherical nuclei
Energy Technology Data Exchange (ETDEWEB)
Daoutidis, Ioannis
2009-10-01
Covariant density functional theory is used to analyze the nuclear response in the external multipole fields. The investigations are based on modern functionals with zero range and density dependent coupling constants. After a self-consistent solution of the Relativistic Mean Field (RMF) equations for the nuclear ground states multipole giant resonances are studied within the Relativistic Random Phase Approximation (RRPA), the small amplitude limit of the time-dependent RMF. The coupling to the continuum is treated precisely by calculating the single particle Greens-function of the corresponding Dirac equation. In conventional methods based on a discretization of the continuum this was not possible. The residual interaction is derived from the same RMF Lagrangian. This guarantees current conservation and a precise decoupling of the Goldstone modes. For nuclei with open shells pairing correlations are taken into account in the framework of BCS theory and relativistic quasiparticle RPA. Continuum RPA (CRPA) presents a robust method connected with an astonishing reduction of the numerical effort as compared to conventional methods. Modes of various multipolarities and isospin are investigated, in particular also the newly discovered Pygmy modes in the vicinity of the neutron evaporation threshold. The results are compared with conventional discrete RPA calculations as well as with experimental data. We find that the full treatment of the continuum is essential for light nuclei and the study of resonances in the neighborhood of the threshold. (orig.)
$\\beta$ - decay asymmetry in mirror nuclei: A = 9
Axelsson, L E; Smedberg, M
2002-01-01
Investigations of light nuclei close to the drip lines have revealed new and intriguing features of the nuclear structure. The occurrence of halo structures in loosely bound systems has had a great impact on the nuclear physics research in the last years. As intriguing but not yet solved is the nature of transitions with very large $\\beta$ - strength. \\\\ \\\\We report here on the investigation of this latter feature by an accurate measurement of the $\\beta$ - decay asymmetry between the mirror nuclei in the A=9 mass chain.\\\\ \\\\The possible asymmetry for the decay to the states around 12 MeV is interesting not only due to the fact that the individual B$_{GT}$ values are large (with large overlap in wave-functions, an unambiguous interpretation is much easier made), but also due to the special role played by this transition for the $^{9}$Li decay. It seems to belong to a class of high-B$_{GT}$ transitions observed at the neutron drip line and has been suggested to be due either to a lowering of the giant Gamow-Te...
Inference in hybrid Bayesian networks
DEFF Research Database (Denmark)
Lanseth, Helge; Nielsen, Thomas Dyhre; Rumí, Rafael
2009-01-01
Since the 1980s, Bayesian Networks (BNs) have become increasingly popular for building statistical models of complex systems. This is particularly true for boolean systems, where BNs often prove to be a more efficient modelling framework than traditional reliability-techniques (like fault trees...... decade's research on inference in hybrid Bayesian networks. The discussions are linked to an example model for estimating human reliability....
Bayesian inference for Hawkes processes
DEFF Research Database (Denmark)
Rasmussen, Jakob Gulddahl
The Hawkes process is a practically and theoretically important class of point processes, but parameter-estimation for such a process can pose various problems. In this paper we explore and compare two approaches to Bayesian inference. The first approach is based on the so-called conditional...
Bayesian inference for Hawkes processes
DEFF Research Database (Denmark)
Rasmussen, Jakob Gulddahl
2013-01-01
The Hawkes process is a practically and theoretically important class of point processes, but parameter-estimation for such a process can pose various problems. In this paper we explore and compare two approaches to Bayesian inference. The first approach is based on the so-called conditional...
Bayesian inference for Hawkes processes
DEFF Research Database (Denmark)
Rasmussen, Jakob Gulddahl
The Hawkes process is a practically and theoretically important class of point processes, but parameter-estimation for such a process can pose various problems. In this paper we explore and compare two approaches to Bayesian inference. The first approach is based on the so-called conditional...
On principles of inductive inference
Kostecki, Ryszard Paweł
2011-01-01
We discuss the mathematical and conceptual problems of main approaches to foundations of probability theory and statistical inference and propose new foundational approach, aimed to improve the mathematical structure of the theory and to bypass the old conceptual problems. In particular, we introduce the intersubjective interpretation of probability, which is designed to deal with the troubles of `subjective' and `objective' bayesian interpretations.
Regular inference as vertex coloring
Costa Florêncio, C.; Verwer, S.
2012-01-01
This paper is concerned with the problem of supervised learning of deterministic finite state automata, in the technical sense of identification in the limit from complete data, by finding a minimal DFA consistent with the data (regular inference). We solve this problem by translating it in its enti
Type inference for COBOL systems
Deursen, A. van; Moonen, L.M.F.
1998-01-01
Types are a good starting point for various software reengineering tasks. Unfortunately, programs requiring reengineering most desperately are written in languages without an adequate type system (such as COBOL). To solve this problem, we propose a method of automated type inference for these lang
Regular inference as vertex coloring
Costa Florêncio, C.; Verwer, S.
2012-01-01
This paper is concerned with the problem of supervised learning of deterministic finite state automata, in the technical sense of identification in the limit from complete data, by finding a minimal DFA consistent with the data (regular inference). We solve this problem by translating it in its
Statistical inference on variance components
Verdooren, L.R.
1988-01-01
In several sciences but especially in animal and plant breeding, the general mixed model with fixed and random effects plays a great role. Statistical inference on variance components means tests of hypotheses about variance components, constructing confidence intervals for them, estimating them,
Covering, Packing and Logical Inference
1993-10-01
of Operations Research 43 (1993). [34] *Hooker, J. N., Generalized resolution for 0-1 linear inequalities, Annals of Mathematics and A 16 271-286. [35...Hooker, J. N. and C. Fedjki, Branch-and-cut solution of inference prob- lems in propositional logic, Annals of Mathematics and AI 1 (1990) 123-140. [40
Mathematical Programming and Logical Inference
1990-12-01
solution of inference problems in propositional logic, to appear in Annals of Mathematics and Al. (271 Howard, R. A., and J. E. Matheson, Influence...1981). (281 Jeroslow, R., and J. Wang, Solving propositional satisfiability problems, to appear in Annals of Mathematics and Al. [29] Nilsson, N. J
An Introduction to Causal Inference
2009-11-02
legitimize causal inference, has removed causation from its natural habitat, and distorted its face beyond recognition. This exclusivist attitude is...In contrast, when the mediation problem is approached from an exclusivist potential-outcome viewpoint, void of the structural guidance of Eq. (28
Vazquez, Billy
The dusty torus is the key component in the Active Galactic Nuclei (AGN) Unification Scheme that explains the spectroscopic differences between Seyfert galaxies of types 1 and 2. The torus dust is heated by the nuclear source and emits the absorbed energy in the infrared (IR); but because of light travel times, the torus IR emission responds to variations of the nuclear ultraviolet/optical continuum with a delay that corresponds to the size of the emitting region. The results from a mid-infrared (MIR) monitoring campaign using the Spitzer Space Telescope and optical ground-based telescopes (B and V band imaging), which spanned over 2 years and covered a sample of 12 Seyfert galaxies, are presented. The aim was to constrain the distances from the nucleus to the regions in the torus emitting at wavelengths of 3.6 microm and 4.5 microm. MIR light curves showing the variability characteristics of these AGN are presented and the effects of photometric uncertainties on the time-series analysis of the light curves are discussed. Significant variability was observed in the IR light curves of 10 of 12 objects, with relative amplitudes ranging from ˜10% to ˜100% from their mean flux. The "reverberation lags" between the 3.6 microm and 4.5 microm IR bands were determined for the entire sample and between the optical and MIR bands for NGC6418. In NGC6418, the 3.6 microm and 4.5 microm fluxes lagged behind those of the optical continuum by 47.5+2.0-1.9) days and 62.5+2.5-2.9 days, respectively. This is consistent with the inferred lower limit to the sublimation radius for pure graphite grains at T=1800 K but smaller by a factor of 2 than the lower limit for dust grains with a "standard" interstellar medium (ISM) composition. There is evidence that the lags increased following approximately by a factor of 2 increase in luminosity, consistent with an increase in the sublimation radius.
Institute of Scientific and Technical Information of China (English)
QUJIAN; CHUANMAOZHANG; 等
1994-01-01
A cell-free preparation obtained from extracts of activated Xenopus laevis eggs induced chromatin decondensation and nuclear formation from demembranated Xenopus sperm nuclei.Electron microscopy revealed that the reassembled nucleus had a double-layered nuclear memblane,nuclear pore complexes,and decondensed chromatin etc.Indirect immunofluorescence analysis demonstrated the presence of lamina in newly assembled nuclei.Western-blotting results showed that lamin LII was present in egg extracts and in lamina of the reassembled nuclei which were previously reported to contain only egg derived lamin LIII.
Spontaneous evaluative inferences and their relationship to spontaneous trait inferences.
Schneid, Erica D; Carlston, Donal E; Skowronski, John J
2015-05-01
Three experiments are reported that explore affectively based spontaneous evaluative impressions (SEIs) of stimulus persons. Experiments 1 and 2 used modified versions of the savings in relearning paradigm (Carlston & Skowronski, 1994) to confirm the occurrence of SEIs, indicating that they are equivalent whether participants are instructed to form trait impressions, evaluative impressions, or neither. These experiments also show that SEIs occur independently of explicit recall for the trait implications of the stimuli. Experiment 3 provides a single dissociation test to distinguish SEIs from spontaneous trait inferences (STIs), showing that disrupting cognitive processing interferes with a trait-based prediction task that presumably reflects STIs, but not with an affectively based social approach task that presumably reflects SEIs. Implications of these findings for the potential independence of spontaneous trait and evaluative inferences, as well as limitations and important steps for future study are discussed. (c) 2015 APA, all rights reserved).
Are Globular Clusters the Remnant Nuclei of Progenitor Disk Galaxies?
Boeker, Torsten
2007-01-01
The globular cluster system of a typical spheroidal galaxy makes up about 0.25% of the total galaxy mass (McLaughlin 1999). This is roughly the same mass fraction as contained in the nuclear star clus- ter (or stellar nucleus) present in most nearby low-mass galaxies. Motivated by this "coincidence", this Letter discusses a scenario in which globular clusters of present-day galaxies are the surviving nuclei of the dwarf galaxies that - according to the hierarchical merging paradigm of galaxy forma- tion - constitute the "building blocks" of present-day massive galaxies. This scenario, which was first suggested by Freeman (1993), has become more attractive recently in the light of studies that demonstrate a complex star formation history in a number of massive globular clusters.
Refractive effects in the scattering of loosely bound nuclei
Cãrstoiu, F; Tribble, R E; Gagliardi, C A
2004-01-01
A study of the interaction of loosely bound nuclei 6,7Li at 9 and 19 AMeV with light targets has been undertaken. With the determination of unambiguous optical potentials in mind, elastic data for four projectile-target combinations and one neutron transfer reaction 13C(7Li,8Li)12C have been measured on a large angular range. The kinematical regime encompasses a region where the mean field (optical potential) has a marked variation with mass and energy, but turns out to be sufficiently surface transparent to allow strong refractive effects to be manifested in elastic scattering data at intermediate angles. The identified exotic feature, a "plateau" in the angular distributions at intermediate angles, is fully confirmed in four reaction channels and interpreted as a pre-rainbow oscillation resulting from the interference of the barrier and internal barrier farside scattering subamplitudes.
The Halo Occupation Distribution of Active Galactic Nuclei
Chatterjee, Suchetana; Richardson, Jonathan; Zheng, Zheng; Nagai, Daisuke; Di Matteo, Tiziana
2011-01-01
Using a fully cosmological hydrodynamic simulation that self-consistently incorporates the growth and feedback of supermassive black holes and the physics of galaxy formation, we examine the effects of environmental factors (e.g., local gas density, black hole feedback) on the halo occupation distribution of low luminosity active galactic nuclei (AGN). We decompose the mean occupation function into central and satellite contribution and compute the conditional luminosity functions (CLF). The CLF of the central AGN follows a log-normal distribution with the mean increasing and scatter decreasing with increasing redshifts. We analyze the light curves of individual AGN and show that the peak luminosity of the AGN has a tighter correlation with halo mass compared to instantaneous luminosity. We also compute the CLF of satellite AGN at a given central AGN luminosity. We do not see any significant correlation between the number of satellites with the luminosity of the central AGN at a fixed halo mass. We also show ...
Active Galactic Nuclei Discovered in the Kepler Mission
Shaya, Edward J; Mushotzky, Richard
2015-01-01
We report on candidate active galactic nuclei (AGN) discovered during the monitoring of $\\sim$500 bright (r < 18 mag) galaxies over several years with the Kepler Mission. Most of the targets were sampled every 30 minutes nearly continuously for a year or more. Variations of 0.001 mag and often less could be detected reliably. About 4.0% (19) of our random sample continuously fluctuated with amplitudes increasing with longer timescales, but the majority are close to the limits of detectability with Kepler. We discuss our techniques to mitigate the long term instrumental trends in Kepler light curves and our resulting structure function curves. The amplitudes of variability over four month periods, as seen in the structure functions and PSDs, can dramatically change for many of these AGN candidates. Four of the candidates have features in their Structure Functions that may indicate quasi-periodic behavior, although other possibilities are discussed.
Magnetic moments of odd spherical nuclei
Energy Technology Data Exchange (ETDEWEB)
Levon, A.I.; Fedotkin, S.N.; Vdovin, A.I.
1986-06-01
Using the quasiparticle-phonon model, the magnetic moments of the ground state and several of the excited states are calculated for spherical nuclei. The polarization of the core is taken into account, by means of 1+ phonons, as well as 2/sup +/ and 3/sup -/ excitations, which give a collective contribution to the magnetic moment.
Neutrino Processes with Hot Nuclei in Supernovae
Dzhioev, A. A.; Vdovin, A. I.
In this paper, we calculate cross sections for charged-current neutrino-nucleus processes occuring under presupernova conditions. To treat thermal effects we extend self-consistent Skyrme-QRPA calculations to finite temperature by using the formalism of thermo field dynamics. The numerical results are presented for the sample nuclei, $^{56}$Fe and $^{82}$Ge
Fisica degli atomi e dei nuclei
Bernardini, Carlo
1965-01-01
Evidenza della struttura atomica della materia ; le proprietà degli atomi e la meccanica atomica ; gli atomi e le radiazioni elettromagnetiche ; struttura microscopica dello stato gassoso ; struttura microscopica dello stato liquido ; struttura microscopica della stato solido ; proprietà elettriche e magnetiche delle sostanze ; proprietà dei nuclei degli atomi ; le particelle elementari.
Test of Pseudospin Symmetry in Deformed Nuclei
Ginocchio, J N; Meng, J; Zhou, S G; Zhou, Shan-Gui
2004-01-01
Pseudospin symmetry is a relativistic symmetry of the Dirac Hamiltonian with scalar and vector mean fields equal and opposite in sign. This symmetry imposes constraints on the Dirac eigenfunctions. We examine extensively the Dirac eigenfunctions of realistic relativistic mean field calculations of deformed nuclei to determine if these eigenfunctions satisfy these pseudospin symmetry constraints.
Magnetic Dipole Sum Rules for Odd Nuclei
Ginocchio, J N
1997-01-01
Sum rules for the total- and scissors-mode M1 strength in odd-A nuclei are derived within the single-j interacting boson-fermion model. We discuss the physical content and geometric interpretation of these sum rules and apply them to ^{167}Er and ^{161}Dy. We find consistency with the former measurements but not with the latter.
Spectroscopic Studies of Exotic Nuclei at ISOLDE
2002-01-01
Experiment IS50 is designed to: a) Investigate the full range of the @b strength function of heavy (A~$>$~48)~K nuclei b)~Study the decay of isomeric states in n-deficient bromine nuclei (A~=~72 and 70). The heavy K isotopes appeared to have complex decay schemes, including feeding by the @b-decay of levels having open neutron channels (Beta decay energy Q(@b) exceeds neutron binding energy S^n); in addition, a large fraction of the delayed transitions populate excited levels in the daughter nuclei. The allowed @b-decay selects states in the daughter nucleus with wave functions having a large overlap with the initial state. Hence, the @b strength functions, deduced from these deca reveal simple structures correlated to the particle-hole excitation energies in the Ca nuclei. These results are valuable for the application of the shell-model calculations far from stability. The delayed neutron spectra are measured with a large area curved scintillator in coincidence either with high resolution Ge(Li) detectors, ...