Publications

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An investigation of the appearance of a long range nuclear potential in ultra low energy nuclear synthesis

Shinsho Oryu, Takashi Watanabe, Yasuhisa Hiratsuka, Masayuki Takeda

SciPost Phys. Proc. 3, 050 (2020) · published 27 February 2020 | · pdf

A new potential, the $general$ $particle$ $transfer$ $potential$: so called ``GPT'' potential was represented in the previous paper which indicates a Yukawa-type potential for shorter range, but a $1/r^n$-type potential for longer range where $n=2$ includes the Efimov-like potential in the hadron system. In order to confirm the existence of a GPT potential, we investigate the possibility of Cs+2d$\rightarrow$La reaction on the three-ion quasi-molecule CsD$_2$ which is covered by twelve Pd or a CsD$_2$Pd$_{12}$-cluster, where the three-body bound states and wave functions for D-Cs-D molecular and d-Cs-d nuclear systems are calculated. We obtain an approximate E2-transition from the molecular states to the nuclear states. The transition ratio between the short range nuclear potential with the $1/r^2$-type long range potential and without long range potential is $W_{i\rightarrow f}^{E2';L}/W_{i\rightarrow f}^{E2';S}\approx 10^8$. If the reaction Cs+2D$\rightarrow$La is experimentally observed, then the existence of the GPT potential could be confirmed.

2 citations
Smearing of causality by compositeness divides dispersive approaches into exact ones and precision-limited ones

Felipe J. Llanes-Estrada, Raúl Roldán-González

SciPost Phys. Core 5, 016 (2022) · published 29 March 2022 | · pdf

Scattering off the edge of a composite particle or finite--range interaction can precede that off its center. An effective theory treatment with pointlike particles and contact interactions must find that the scattered experimental wave is slightly advanced, in violation of causality (the fundamental underlying theory being causal). In practice, partial--wave or other projections of multivariate amplitudes exponentially grow with ${\rm Im}(E)$, so that analyticity is not sufficient to obtain a dispersion relation for them, but only for a slightly modified function (the modified relations additionally connect different $J$). This can limit the precision of certain dispersive approaches to compositeness based on Cauchy's theorem. Awareness of this may be of interest to some dispersive tests of the Standard Model with hadrons, and to unitarization methods used to extend electroweak effective theories. Interestingly, the Inverse Amplitude Method is safe (as the inverse amplitude has the opposite, convergent behavior allowing contour closure). Generically, one-dimensional sum rules such as for the photon vacuum polarization, form factors or the Adler function are not affected by this uncertainty; nor are fixed-$t$ dispersion relations, cleverly constructed to avoid it and whose consequences are solid.

2 citations
The eikonal model of reactions involving exotic nuclei; Roy Glauber's legacy in today's nuclear physics

Pierre Capel

SciPost Phys. Proc. 3, 017 (2020) · published 25 February 2020 | · pdf

In this contribution, the eikonal approximation developed by Roy Glauber to describe high-energy quantum collisions is presented. This approximation has been-and still is-extensively used to analyse reaction measurements performed to study the structure of nuclei far from stability. This presentation focuses more particularly on the application of the eikonal approximation to the study of halo nuclei in modern nuclear physics. To emphasise Roy Glauber's legacy in today's nuclear physics, recent extensions of this model are reviewed.

2 citations
Three-nucleon force effects in nucleon-deuteron scattering at backward angles

Souichi Ishikawa

SciPost Phys. Proc. 3, 054 (2020) · published 27 February 2020 | · pdf

Elastic and breakup cross sections in nucleon-deuteron scattering at intermediate energies are calculated using a realistic two-nucleon potential and three-nucleon potentials based on the exchange of two pions among three nucleons. Attractive effects of the pion-exchange at medium range region in the three-nucleon potential are recovered by using a shorter range cutoff. It is shown that these effects increase the cross sections at backward angles, which tends to reduce discrepancies between theoretical calculations and experimental data.

2 citations
Four-body Faddeev-type calculation of the $\bar{K}NNN$ system: Preliminary results

Nina V. Shevchenko

SciPost Phys. Proc. 3, 041 (2020) · published 27 February 2020 | · pdf

The paper is devoted to the $\bar{K}NNN$ system, consisting of an antikaon and three nucleons. Four-body Faddeev-type AGS equations are being solved in order to find possible quasi-bound state in the system.

2 citations
Short range nucleon correlations studied with electron and photon probes

I.J. Douglas MacGregor

SciPost Phys. Proc. 3, 010 (2020) · published 24 February 2020 | · pdf

This paper reviews experimental research into two- and three-body nucleon-nucleon interactions, carried out by the University of Glasgow Nuclear Physics research group. A key aim of these studies has been to elucidate the role of short-range nucleon-nucleon correlations (SRC). Studies of photon-induced two- and three-nucleon emission reactions from a range of light nuclei, carried out at the 840 MeV Mainz electron microtron MAMI-B, have provided detailed information on the contributing mechanisms. More recent electron scattering studies at the 6.0 GeV Jefferson Laboratory have probed SRC at high values of Q2 and xB and suggested a connection between SRC and the EMC effect.

2 citations
Study of deuteron-proton backward elastic scattering at intermediate energies

Nadezhda Ladygina

SciPost Phys. Proc. 3, 053 (2020) · published 27 February 2020 | · pdf

We study deuteron- proton elastic scattering in the deuteron energy range between 500 MeV and 2~GeV at the cms scattering angle $\theta^*\ge 140^\circ$. The reaction is considered in the relativistic multiple scattering expansion framework. The four reaction mechanisms are included into consideration: one-nucleon exchange, single scattering, double scattering, and the term corresponding to the delta excitation in the intermediate state. The model is applied to describe the angular dependence of the differential cross section at the deuteron energies of between 880 and 1300 MeV. Also the energy dependence of the differential cross section and polarisation observables such as tensor analyzing power $T_{20}$ and polarization transfer from the deuteron to proton $\varkappa$ are considered at the scattering angle equal to 180$^\circ$. Contributions of the different reaction mechanisms into the reaction amplitude are demonstrated in comparison with the existing experimental data.

2 citations
A time-dependent Hartree-Fock study of triple-alpha dynamics

Paul D. Stevenson, J. L. Willerton

SciPost Phys. Proc. 3, 047 (2020) · published 27 February 2020 | · pdf

Time-dependent Hartree-Fock calculations have been performed for fusion reactions of He-4 + He-4 -> Be*-8, followed by He-4 + Be*-8 . Depending on the orientation of the initial state, a linear chain vibrational state or a triangular vibration is found in 12C, with transitions between these states observed. The vibrations of the linear chain state and the triangular state occur at ~9 and 4 MeV respectively.

2 citations
Description of continuum structures in a discrete basis: Three-body resonances and two-nucleon decays

Jesús Casal, Manuela Rodríguez-Gallardo, José M. Arias, Joaquín Gómez-Camacho, Lorenzo Fortunato, Andrea Vitturi

SciPost Phys. Proc. 3, 036 (2020) · published 26 February 2020 | · pdf

Weakly bound and unbound three-body nuclei are studied by using the pseudostate method within the hyperspherical formalism. After introducing the theoretical framework, the method is applied first to the $\boldsymbol{^9}$Be nucleus, showing a good agreement with the available data for its low-lying dipole response. Then, recent results on the structure and decay of the two-neutron emitters $\boldsymbol{^{26}}$O and $\boldsymbol{^{16}}$Be are presented. In particular, the role of the $\boldsymbol{n}$-$\boldsymbol{n}$ correlation in shaping their properties is discussed.

2 citations
A somewhat random walk through nuclear and particle physics

Thomas D. Cohen, Nicholas R. Poniatowski

SciPost Phys. Lect. Notes 34 (2021) · published 20 September 2021 | · pdf

These notes are an outgrowth of an advanced undergraduate course taught at the University of Maryland, College Park. They are intended as an introduction to various aspects of particle and nuclear physics with an emphasis on the role of symmetry. The basic philosophy is to introduce many of the fundamental ideas in nuclear and particle physics using relatively sophisticated mathematical tools -- but to do so in as a simplified a context to explain the underlying ideas. Thus, for example, the Higgs mechanism is discussed in terms of an Abelian Higgs model. The emphasis is largely, but not entirely theoretical in orientation. The goal is for readers to develop an understanding of many of the underlying issues in a relatively sophisticated way.

1 citation

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