Showing papers by "Carlos A. Bertulani published in 2016"
TL;DR: In this article, the synthesis of nuclei in diverse cosmic scenarios is reviewed, with a summary of the basic concepts involved before a discussion of the current status in each case is made.
110 citations
TL;DR: In this paper, quasi-free scattering reactions of the type (p, 2p) were measured for the first time exclusively in complete and inverse kinematics, using a 12C beam at an energy of ~400 MeV/u as a benchmark.
47 citations
TL;DR: In this paper, a report on a recent experiment performed via the Trojan Horse Method (THM) is presented and the results are given and compared with the ones known in the literature, both direct and indirect.
Abstract: Crucial information on novae nucleosynthesis is linked to the abundance of 18F , which, due to great improvements in gamma-ray astronomy, can be detected in explosive environments. Therefore, the reaction network producing and destroying this radioactive isotope has been extensively studied in the last years. Among those reactions, the 18F(p,
$\alpha$
)15O cross section has been measured by means of several dedicated experiments, both using direct and indirect methods. The presence of resonances in the energy region of astrophysical interest has been reported by many authors. In the present work a report on a recent experiment performed via the Trojan Horse Method (THM) is presented and the results are given and compared with the ones known in the literature, both direct and indirect. Data arising from THM measurements are then averaged and the reaction rate calculated in the novae energy range.
44 citations
TL;DR: In this article, the authors show that instead of an atomic physics solution of the electron screening puzzle, the reason for the large screening potential values is in fact due to clusterization effects in nuclear reactions, in particular for reaction involving light nuclei.
39 citations
TL;DR: In this article, the angular distribution of the photon was calculated in the potential model and the expressions for the total cross section and astrophysical factor were derived by integrating the differential cross section over the photon's solid angle.
Abstract: During the Big Bang, ${}^{6}{\rm Li}$ was synthesized via the ${}^{2}{\rm H}(\alpha,\gamma){}^{6}{\rm Li}$ reaction. After almost 25 years of the failed attempts to measure the ${}^{2}{\rm H}(\alpha,\gamma){}^{6}{\rm Li}$ reaction in the lab at the Big Bang energies, just recently the LUNA collaboration presented the first successful measurements at two different Big Bang energies [M. Anders {\it et al.}, Phys. Rev. Lett. {\bf 113}, 042501 (2014)]. In this paper we will discuss how to improve the accuracy of the direct experiment. To this end the photon's angular distribution is calculated in the potential model. It contains contributions from electric dipole and quadrupole transitions and their interference, which dramatically changes the photon's angular distribution. The calculated distributions at different Big Bang energies have a single peak at $\sim 50^{\circ}$. These calculations provide the best kinematic conditions to measure the ${}^{2}{\rm H}(\alpha,\gamma){}^{6}{\rm Li}$ reaction. The expressions for the total cross section and astrophysical factor are also derived by integrating the differential cross section over the photon's solid angle. The LUNA data are in excellent agreement with our calculations using a potential approach combined with a well established asymptotic normalization coefficient for ${}^{6}{\rm Li} \to \alpha +d$. Comparisons of the available experimental data for the $S_{24}$ astrophysical factor and different calculations are presented. The Big Bang lithium isotopic ratio ${}^{6}{\rm Li}/^{7}{\rm Li} = (1.5 \pm 0.3)\times 10^{-5}$ following from the LUNA data and the present analysis are discussed in the context of the disagreement between the observational data and the standard Big Bang model, which constitutes the second Lithium problem.
33 citations
Posted Content•
TL;DR: In this paper, photo-absorption cross sections in the most deformed nuclei, 150Nd and 152Sm, exhibit a pronounced asymmetry rather than a distinct double-hump structure expected as a signature of K-splitting.
Abstract: Proton inelastic scattering experiments at energy E_p = 200 MeV and a spectrometer scattering angle of 0 degree were performed on 144,146,148,150Nd and 152Sm exciting the IsoVector Giant Dipole Resonance (IVGDR). Comparison with results from photo-absorption experiments reveals a shift of resonance maxima towards higher energies for vibrational and transitional nuclei. The extracted photo-absorption cross sections in the most deformed nuclei, 150Nd and 152Sm, exhibit a pronounced asymmetry rather than a distinct double-hump structure expected as a signature of K-splitting. This behaviour can be related to the proximity of these nuclei to the critical point of the phase shape transition from vibrators to rotors with a soft quadrupole deformation potential. Self-consistent random-phase approximation (RPA) calculations using the SLy6 Skyrme force provide a relevant description of the IVGDR shapes deduced from the present data
16 citations
TL;DR: In this paper, the synthesis of nuclei in diverse cosmic scenarios is reviewed, with a summary of the basic concepts involved before a discussion of the current status in each case is made.
Abstract: The synthesis of nuclei in diverse cosmic scenarios is reviewed, with a summary of the basic concepts involved before a discussion of the current status in each case is made. We review the physics of the early universe, the proton to neutron ratio influence in the observed helium abundance, reaction networks, the formation of elements up to beryllium, the inhomogeneous Big Bang model, and the Big Bang nucleosynthesis constraints on cosmological models. Attention is paid to element production in stars, together with the details of the pp chain, the pp reaction, $^3$He formation and destruction, electron capture on $^7$Be, the importance of $^8$B formation and its relation to solar neutrinos, and neutrino oscillations. Nucleosynthesis in massive stars is also reviewed, with focus on the CNO cycle and its hot companion cycle, the rp-process, triple-$\alpha$ capture, and red giants and AGB stars. The stellar burning of carbon, neon, oxygen, and silicon is presented in a separate section, as well as the slow and rapid nucleon capture processes and the importance of medium modifications due to electrons also for pycnonuclear reactions. The nucleosynthesis in cataclysmic events such as in novae, X-ray bursters and in core-collapse supernovae, the role of neutrinos, and the supernova radioactivity and light-curve is further discussed, as well as the structure of neutron stars and its equation of state. A brief review of the element composition found in cosmic rays is made in the end.
13 citations
TL;DR: Evidence for the fleeting existence of a system of four neutrons known as the tetraneutron is reported, a hypothetical state in nuclear physics, has implications for research into neutron stars.
Abstract: A system of four neutrons known as the tetraneutron is a hypothetical state in nuclear physics. The report of evidence for the fleeting existence of this state has implications for research into neutron stars.
13 citations
TL;DR: In this paper, the exotic charmonium production in the CERN Large Hadron Collider was investigated and the experimental results demonstrate that the experimental study of these processes is feasible and can be used to constrain the theoretical decay widths and shed some light on the configuration of the considered multiquark states.
Abstract: In this paper we investigate the exotic charmonium production in $\ensuremath{\gamma}\ensuremath{\gamma}$ interactions present in proton-proton, proton-nucleus, and nucleus-nucleus collisions at the CERN Large Hadron Collider energies as well as for the proposed energies of the Future Circular Collider. Our results demonstrate that the experimental study of these processes is feasible and can be used to constrain the theoretical decay widths and shed some light on the configuration of the considered multiquark states.
9 citations
Chalmers University of Technology1, University of Groningen2, GSI Helmholtz Centre for Heavy Ion Research3, Goethe University Frankfurt4, University of Birmingham5, Michigan State University6, Helmholtz-Zentrum Dresden-Rossendorf7, Texas A&M University8, Spanish National Research Council9, University of Vigo10, University of Surrey11, Saha Institute of Nuclear Physics12, University of Liverpool13, Kurchatov Institute14, University of Giessen15, Hungarian Academy of Sciences16, Technische Universität Darmstadt17, Saint Mary's University18, Complutense University of Madrid19, Aarhus University20, University of Lisbon21, Technische Universität München22, Daresbury Laboratory23, University of Cologne24, Dresden University of Technology25, University of Notre Dame26, University of Edinburgh27
TL;DR: In this article, one-proton removal cross sections with different final neutron numbers (1pxn) for relativistic C10,12-18 and B10-15 isotopes impinging on a carbon target were measured.
Abstract: Background: Models describing nuclear fragmentation and fragmentation fission deliver important input for planning nuclear physics experiments and future radioactive ion beam facilities. These models are usually benchmarked against data from stable beam experiments. In the future, two-step fragmentation reactions with exotic nuclei as stepping stones are a promising tool for reaching the most neutron-rich nuclei, creating a need for models to describe also these reactions. Purpose: We want to extend the presently available data on fragmentation reactions towards the light exotic region on the nuclear chart. Furthermore, we want to improve the understanding of projectile fragmentation especially for unstable isotopes. Method: We have measured projectile fragments from C10,12-18 and B10-15 isotopes colliding with a carbon target. These measurements were all performed within one experiment, which gives rise to a very consistent data set. We compare our data to model calculations. Results: One-proton removal cross sections with different final neutron numbers (1pxn) for relativistic C10,12-18 and B10-15 isotopes impinging on a carbon target. Comparing model calculations to the data, we find that the epax code is not able to describe the data satisfactorily. Using abrabla07 on the other hand, we find that the average excitation energy per abraded nucleon needs to be decreased from 27 MeV to 8.1 MeV. With that decrease abrabla07 describes the data surprisingly well. Conclusions: Extending the available data towards light unstable nuclei with a consistent set of new data has allowed a systematic investigation of the role of the excitation energy induced in projectile fragmentation. Most striking is the apparent mass dependence of the average excitation energy per abraded nucleon. Nevertheless, this parameter, which has been related to final-state interactions, requires further study.
9 citations
TL;DR: In this paper, a new SU(3) gauge group of transformations has been proposed, as a natural extension of the Standard Model (SM), and the cross section for the elastic scattering of a dark proton by an ordinary proton is compared to the WIMP-nucleon experimental upper bounds.
Abstract: We propose a mirror model for ordinary and dark matter that assumes a new SU(3) gauge group of transformations, as a natural extension of the Standard Model (SM). A close study of big bang nucleosynthesis, baryon asymmetries, cosmic microwave background bounds, galaxy dynamics, together with the Standard Model assumptions, help us to set a limit on the mass and width of the new gauge boson. The cross section for the elastic scattering of a dark proton by an ordinary proton is estimated and compare to the WIMP–nucleon experimental upper bounds. It is observed that all experimental bounds for the various cross sections can be accommodated consistently within the gauge model. We also suggest a way for direct detection of the new gauge boson via one example of a SM forbidden process: $e^{+} + p \rightarrow \mu ^{+} + X$
, where X=Λ or Λ
c
.
TL;DR: In this paper, the authors used quasi-separable potentials to calculate the neutron and proton radiative capture cross sections on 12C and showed that the results obtained are in good agreement with the available experimental data.
Abstract: We study radiative capture reactions using quasi-separable potentials. This procedure allows an easier treatment of non-local effects that can be extended to three-body problems. Using this technique, we calculate the neutron and proton radiative capture cross sections on 12C. The results obtained are shown to be in good agreement with the available experimental data.
Technische Universität Darmstadt1, University of Santiago de Compostela2, Texas A&M University–Commerce3, Spanish National Research Council4, University of Liverpool5, Kurchatov Institute6, Goethe University Frankfurt7, Complutense University of Madrid8, Aarhus University9, Chalmers University of Technology10, University of Mainz11, Uppsala University12, Technische Universität München13, Bhabha Atomic Research Centre14, Frankfurt Institute for Advanced Studies15, University of Notre Dame16
TL;DR: In this article, the excitation and decay of narrow resonant states in 17Ne have been investigated using the isobaric multiplet mass equation and their spins and parities. And the resulting transition probabilities provide information relevant for a better understanding of the 17Ne structure.
05 Jan 2016
TL;DR: The Facility for Antiproton and Ion Research (FAIR) will offer unique, unprecedented opportunities to investigate many of the important reactions as mentioned in this paper, even far away from the valley of stability, allowing the investigation of isotopes involved in processes as exotic as the r or rp processes.
Abstract: The nucleosynthesis of elements beyond iron is dominated by neutron captures in the s and r processes. However, 32 stable, proton-rich isotopes cannot be formed during those processes, because they are shielded from the s-process flow and r-process beta-decay chains. These nuclei are attributed to the p and rp process. For all those processes, current research in nuclear astrophysics addresses the need for more precise reaction data involving radioactive isotopes. Depending on the particular reaction, direct or inverse kinematics, forward or time-reversed direction are investigated to determine or at least to constrain the desired reaction cross sections. The Facility for Antiproton and Ion Research (FAIR) will offer unique, unprecedented opportunities to investigate many of the important reactions. The high yield of radioactive isotopes, even far away from the valley of stability, allows the investigation of isotopes involved in processes as exotic as the r or rp processes.
Helmholtz-Zentrum Dresden-Rossendorf1, Dresden University of Technology2, University of Santiago de Compostela3, Goethe University Frankfurt4, University of Birmingham5, Technische Universität Darmstadt6, Lund University7, Texas A&M University–Commerce8, Spanish National Research Council9, Centre national de la recherche scientifique10, University of Vigo11, University of Surrey12, Saha Institute of Nuclear Physics13, University of Liverpool14, Petersburg Nuclear Physics Institute15, Instituto Superior Técnico16, Hungarian Academy of Sciences17, Saint Mary's University18, Complutense University of Madrid19, Aarhus University20, Technische Universität München21, Chalmers University of Technology22, Daresbury Laboratory23, Beihang University24, University of Notre Dame25, University of Edinburgh26, University of Cologne27
TL;DR: In this article, a Coulomb dissociation experiment on N20,21 ions was conducted and the Coulomb cross section was determined in a kinematically complete experiment using the detailed balance theorem.
Abstract: Neutron-rich light nuclei and their reactions play an important role in the creation of chemical elements. Here, data from a Coulomb dissociation experiment on N20,21 are reported. Relativistic N20,21 ions impinged on a lead target and the Coulomb dissociation cross section was determined in a kinematically complete experiment. Using the detailed balance theorem, the N19(n,γ)N20 and N20(n,γ)N21 excitation functions and thermonuclear reaction rates have been determined. The N19(n,γ)N20 rate is up to a factor of 5 higher at T<1GK with respect to previous theoretical calculations, leading to a 10% decrease in the predicted fluorine abundance.
TL;DR: In this article, the Coulomb excitation of pygmy dipole resonances (PDR) in heavy ion reactions at 100 MeV/nucleon and above was studied.
TL;DR: In this paper, the role of core excitation and evaporation processes in deeply bound nucleon removal from asymmetric nuclei at intermediate energies was investigated, and it was shown that non-direct reaction processes play an important role in deeply-bound nucleon extraction from asymmetrical nuclei.
Abstract: Background: For the deeply bound one-nucleon removal at intermediate energies using a $^{9}\text{Be}$ or $^{12}\text{C}$ target, a strong reduction of cross section was observed relative to the prediction of eikonal theoretical model. The large disagreement has not been explained and the systematic trend is inconsistent with results from transfer reactions. The recently observed asymmetric parallel momentum distribution of the knockout residue indicates the significant dissipative core-target interaction in the knockout reaction with a composite target, implying new reaction mechanisms beyond the eikonal reaction descriptions.Purpose: To investigate the reaction mechanism for deeply bound nucleon removal at intermediate energies.Method: Neutron removal from $^{14}\text{O}$ using a $^{12}\text{C}$ target at 60 MeV/nucleon was performed. Nucleon knockout cross sections were measured. The unbound excited states of $^{13}\text{O}$ were reconstructed by using the invariant mass method with the residues and the associated decay protons measured in coincidence. The measured cross sections are compared with an intra-nuclear cascade (INC) prediction.Results: The measured cross section of ($^{14}\text{O}$, $^{11}\text{C}$) is 60(9) mb, which is 3.5 times larger than that of ($^{14}\text{O}$, $^{13}\text{O}$) channel. This $2pn$-removal cross section is consistent with INC prediction, which is 66 mb with the main contribution being non-direct reaction processes. On the other hand, the upper limit of the cross section for one-neutron removal from $^{14}\text{O}$ followed by proton evaporation is 4.6(20) mb, integrated up to 6 MeV above the proton separation energy of $^{13}\text{O}$. The calculated total cross section for such reaction processes by the INC model is 2.5 mb, which is within the measured upper limit.Conclusions: The data provide the first constraint on the role of core excitation and evaporation processes in deeply bound nucleon removal from asymmetric nuclei. The experiment results suggest that non-direct reaction processes, which are not considered in the eikonal model, play an important role in deeply bound nucleon removal from asymmetric nuclei at intermediate energies.
Journal Article•
TL;DR: In this paper, the Coulomb excitation of pygmy dipole resonances (PDR) in heavy ion reactions at 100 MeV/nucleon and above was studied.
Abstract: We study the Coulomb excitation of pygmy dipole resonances (PDR) in heavy ion reactions at 100 MeV/nucleon and above. The reactions Ni 68 + Au 197 and Ni 68 + Pb 208 are taken as practical examples. Our goal is to address the question of the influence of giant resonances on the PDR as the dynamics of the collision evolves. We show that the coupling to the giant resonances affects considerably the excitation probabilities of the PDR, a result that indicates the need of an improved theoretical treatment of the reaction dynamics at these bombarding energies.
14 Apr 2016
TL;DR: In this article, the authors discuss recent developments in indirect methods used in nuclear astrophysics to determine the capture cross sections and subsequent rates of various stellar burning processes, when it is difficult to perform the corresponding direct measurements.
Abstract: We discuss recent developments in indirect methods used in nuclear astrophysics to determine the capture cross sections and subsequent rates of various stellar burning processes, when it is difficult to perform the corresponding direct measurements. We discuss in brief, the basic concepts of Asymptotic Normalization Coefficients, the Trojan Horse Method, the Coulomb Dissociation Method, (d,p), and charge-exchange reactions.
TL;DR: In this article, the cosmological lithium problem is discussed and a few recent attempts to find theoretical solutions by Texas A&M University (Commerce & College Station) are reported.
Abstract: After a brief review of the cosmological lithium problem, we report a few recent attempts to find theoretical solutions by our group at Texas A&M University (Commerce & College Station). We will discuss our studies on the theoretical description of electron screening, the possible existence of parallel universes of dark matter, and the use of non-extensive statistics during the Big Bang nucleosynthesis epoch. Last but not least, we discuss possible solutions within nuclear physics realm. The impact of recent measurements of relevant nuclear reaction cross sections for the Big Bang nucleosynthesis based on indirect methods is also assessed. Although our attempts may not able to explain the observed discrepancies between theory and observations, they suggest theoretical developments that can be useful also for stellar nucleosynthesis.
TL;DR: In this article, the authors make a short review of recent progress on topics of current interest in nuclear physics and nuclear astrophysics and present a test case based on applications of such potentials to phase-shift analysis.
Abstract: In this contribution we make a short review of recent progress on topics of current interest in nuclear physics and nuclear astrophysics. In particular, we discuss a re-analysis of the extraction of the dipole response of the pigmy resonance in $^{68}$Ni based on a continuum discretized coupled-channels calculation in relativistic Coulomb excitation experiments. We also discuss the forthcoming progresses made by our group on the Alt-Sandhas-Grassberber approach to (d,p) reactions and future expectations. The role of separable potentials in solving such equations with a test case based on applications of such potentials to phase-shift analysis is also presented.
Posted Content•
TL;DR: In this article, the effects of Parton distribution functions (PDFs) on particle production at the CERN Large Hadron Collider (LHC) have been explored using existing and forthcoming data, e.g., from ALICE and CMS.
Abstract: Vector meson production in ultra-peripheral pA and AA collisions at the CERN Large Hadron Collider (LHC) are very sensitive to Parton Distribution Functions (PDF) as well as to their leading-order, next-to-leading-order, and medium corrections. This process is a complimentary tool to explore the effects of different PDFs in particle production in proton-nucleus and nucleus-nucleus central collisions. Existing and forthcoming data available, e.g., from ALICE and CMS, may be used in conjunction with our theoretical predictions to constrain the PDFs. We make predictions for rapidity distributions and for cross sections of J/$\psi$ , $\psi(2S)$ and $\Upsilon$ production at $\sqrt{s_{NN}}=2.76$ TeV and $\sqrt{s_{NN}}=5$ TeV. We use the second energy as representative for the Run 2 of PbPb collisions at the LHC.
10 Oct 2016
TL;DR: In this paper, quasi-free reactions in inverse kinematics at relativistic energies were used to investigate single-particle structure of stable and exotic nuclei in a most direct way.
Abstract: According to the Independent Particle Model (IPM) the single particle states are fully occupied with a spectroscopic factor one. However in electron-induced proton knockout reactions a reduction of single-particle strengths has been observed to about 60-70% for stable nuclei in comparison to the IPM. This finding has confirmed by nuclear knockout reactions using stable and exotic beams, however, with a strong dependency on the proton-neutron asymmetry. To understand this dependency quantitatively a complementary approach, quasi-free reactions, is introduced. Quasi-free knockout reactions in inverse kinematics at relativistic energies allows us to investigate singleparticle structure of stable and exotic nuclei in a most direct way.
07 Jul 2016
TL;DR: In this paper, the cosmological lithium problem is discussed and a few recent attempts to find theoretical solutions by Texas A&M University (Commerce & College Station) are reported.
Abstract: After a brief review of the cosmological lithium problem, we report a few recent attempts to find theoretical solutions by our group at Texas A&M University (Commerce & College Station). We will discuss our studies on the theoretical description of electron screening, the possible existence of parallel universes of dark matter, and the use of non-extensive statistics during the Big Bang nucleosynthesis epoch. Last but not least, we discuss possible solutions within nuclear physics realm. The impact of recent measurements of relevant nuclear reaction cross sections for the Big Bang nucleosynthesis based on indirect methods is also assessed. Although our attempts may not able to explain the observed discrepancies between theory and observations, they suggest theoretical developments that can be useful also for stellar nucleosynthesis.
Journal Article•
TL;DR: In this paper, the effects of different PDFs in particle production in proton-nucleus and nucleus nucleus central collisions at the CERN Large Hadron Collider (LHC) were explored.
Abstract: Vector meson production in ultra-peripheral pA and AA collisions at the CERN Large Hadron Collider (LHC) are very sensitive to Parton Distribution Functions (PDF) as well as to their leadingorder, next-to-leading-order, and medium corrections. This process is a complimentary tool to explore the effects of different PDFs in particle production in proton-nucleus and nucleus-nucleus central collisions. Existing and forthcoming data available, e.g., from ALICE and CMS, may be used in conjunction with our theoretical predictions to constrain the PDFs. We make predictions for rapidity distributions and for cross sections of J/ψ , ψ(2S) and Υ production at √ sNN = 2.76 TeV and √ sNN = 5 TeV. We use the second energy as representative for the Run 2 of PbPb collisions at the LHC.
TL;DR: In this paper, the authors used quasi-separable potentials to calculate the neutron and proton radiative capture cross sections on C. The results obtained are shown to be in good agreement with the available experimental data.
Abstract: We study radiative capture reactions using quasi-separable potentials. This procedure allows an easier treatment of non-local effects that can be extended to three-body problems. Using this technique, we calculate the neutron and proton radiative capture cross sections on $^{12}$C. The results obtained are shown to be in good agreement with the available experimental data.
01 Jan 2016
05 Jan 2016
TL;DR: In this article, an up-to-date compilation of direct cross sections of d(d,p)t, d (d,n) 3 He and 3 He,p 4 He reactions is given, being these ones among the most uncertain barenucleus cross sections.
Abstract: Big Bang Nucleosynthesis (BBN) requires several nuclear physics inputs and nuclear reaction rates. An up-to-date compilation of direct cross sections of d(d,p)t, d(d,n) 3 He and 3 He(d,p) 4 He reactions is given, being these ones among the most uncertain bare-nucleus cross sections. An intense experimental effort has been carried on in the last decade to apply the Trojan Horse Method (THM) to study reactions of relevance for the BBN and measure their astrophysical S(E)-factor. The reaction rates and the relative error for the four reactions of interest are then numerically calculated in the temperature ranges of relevance for BBN (0.01
Dissertation•
01 Jan 2016
TL;DR: In this article, the authors present an analysis of the relationship between nuclear power and the number of atoms in a nuclear system. Buthelezi, Buthelez, Butheli, N.Kheswa, Kheswa et al., N. Kureba, 11.
Abstract: L.M. Donaldson, 2, ∗ J. Carter, P. von Neumann-Cosel, V.O. Nesterenko, R. Neveling, P.-G. Reinhard, I.T. Usman, P. Adsley, 2, 6 C.A. Bertulani, J.W. Brümmer, E.Z. Buthelezi, G.R.J. Cooper, R.W. Fearick, S.V. Förtsch, H. Fujita, Y. Fujita, M. Jingo, N.Y. Kheswa, W. Kleinig, C.O. Kureba, 11 J. Kvasil, M. Latif, K.C.W. Li, J.P. Mira, F. Nemulodi, P. Papka, 6 L. Pellegri, 2 N. Pietralla, V.Yu. Ponomarev, B. Rebeiro, A. Richter, N.Yu. Shirikova, E. Sideras-Haddad, A.V. Sushkov, F.D. Smit, G.F. Steyn, J.A. Swartz, 6 and A. Tamii iThemba LABS, Old Faure Road, Faure 7131, South Africa School of Physics, University of the Witwatersrand, Johannesburg 2050, South Africa Institut für Kernphysik, Technische Universität Darmstadt, D-64289 Darmstadt, Germany Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Dubna 141980, Russia Institut für Theoretische Physik II, Universität Erlangen, D-91058 Erlangen, Germany Department of Physics, Stellenbosch University, Matieland 7602, South Africa Department of Physics and Astronomy, Texas A&M University-Commerce, Commerce TK 75429, USA School of Geosciences, University of the Witwatersrand, Johannesburg 2050, South Africa Department of Physics, University of Cape Town, Rondebosch 7700, South Africa Research Center for Nuclear Physics, Osaka University, Ibaraki, Osaka 567-0047, Japan Department of Physics and Astronomy, Botswana International University of Science and Technology, P. Bag 16, Palapye, Botswana Institute of Particle and Nuclear Physics, Charles University, CZ-18000, Prague 8, Czech Republic Department of Physics and Astronomy, University of the Western Cape, Bellville, Cape Town 7535, South Africa (Dated: October 2, 2020)
King Saud University1, Technische Universität Darmstadt2, Texas A&M University–Commerce3, University of Liverpool4, Goethe University Frankfurt5, CERN6, Complutense University of Madrid7, Aarhus University8, Akdeniz University9, University of Mainz10, Jagiellonian University11, Uppsala University12, Technische Universität München13, Bhabha Atomic Research Centre14, Centre national de la recherche scientifique15, Kurchatov Institute16, University of Notre Dame17
TL;DR: In this paper, the Coulomb dissociation technique was applied to the time-reversed reaction O-15(2p, gamma) Ne-17 and the excitation energy prior to decay was reconstructed by using the invariant-mass method.
Abstract: The time-reversed reaction O-15(2p, gamma) Ne-17 has been studied by the Coulomb dissociation technique. Secondary 17Ne ion beams at 500 AMeV have been produced by fragmentation reactions of Ne-20 in a beryllium production target and dissociated on a secondary Pb target. The incoming beam and the reaction products have been identified with the kinematically complete LAND-(RB)-B-3 experimental setup at GSI. The excitation energy prior to decay has been reconstructed by using the invariant-mass method. The preliminary differential and integral Coulomb Dissociation cross sections (sigma(Coul)) have been calculated, which provide a photoabsorption (sigma(photo)) and a radiative capture cross section (sigma(cap)). Additionally, important information about the nuclear structure of the Ne-17 nucleus will be obtained. The analysis is in progress.
Posted Content•
TL;DR: In this article, the authors proposed the use of neutron poisons in reactions induced by radioactive beams as a test of theoretical models aiming to relate neutron capture in nuclei with neutron surrogate reactions such as (d,p) reactions.
Abstract: We propose the use of neutron poisons in reactions induced by radioactive beams as a test of theoretical models aiming to relate neutron capture in nuclei with neutron surrogate reactions such as (d,p) reactions. We exploit the approximations necessary to obtain a direct relation between the two reactions; surrogate vs. neutron capture. We also show how this is intimately related to the momentum distribution of the neutron within the deuteron. The models we use are based on the theory of inclusive breakup reactions commonly employed in the treatment of incomplete fusion and surrogate method. Such theories were developed in the 80's by Ichimura, Autern and Vincent [Phys. Rev. C 32, 431 (1985)], Udagawa and Tamura [Phys. Rev. C 24, 1348 (1981)] and Hussein and McVoy [Nucl. Phys. A 445, 124 (1985)]. We use these theories to derive an expression for the proton yield in the reaction A(d,p)B. The capture reaction $n + A \rightarrow B$ is then extracted using reasonable approximations. By recalling an old method proposed by Serber [Phys. Rev. 80, 1098 (1950); Nature 166, 709 (1950)] we explain how the momentum distribution of neutrons within the deuteron will depend on the short-range dependence of the nucleon-nucleon force. The relevance of our work to nucleosynthesis in the rapid neutron capture process is emphasized.