370 research outputs found
Muon Capture on H
No full textThe μ-+H3→νμ+n+n+n capture reaction is studied under full inclusion of final-state interactions. Predictions for the three-body breakup of H3 are calculated with the AV18 potential, augmented by the Urbana IX three-nucleon force. Our results are based on the single-nucleon weak-current operator comprising the dominant relativistic corrections. This work is a natural extension of our investigations of the μ-+He3→νμ+H3,μ-+He3→νμ+n+d and μ-+He3→νμ+n+n+p capture reactions presented in Golak et al. [J. Golak, R. Skibiński, H. Witała, K. Topolnicki, A. E. Elmeshneb, H. Kamada, A. Nogga, and L. E. Marcucci, Phys. Rev. C 90, 024001 (2014)]PRVCAN0556-281310.1103/PhysRevC.90.024001
Muon induced deuteron disintegration in three-dimensions
No full textWe present a three-dimensional (3D) description of muon induced deuteron disintegration. This reaction is treated as the decay of the muonic atom with the muon initially on the lowest K shell. Our aim is to calculate the total and differential decay rates. We work in momentum space and use 3D momentum eigenstates directly. This approach allowed us to calculate the appropriate nuclear matrix elements, necessary building blocks for the differential decay rate, in a single step. For contrast - in classical calculations many partial-waves have to be taken into account. We achieved a very good agreement between the 3D and partial-wave methods for calculations that involve single-nucleon currents. Our result for the total decay rate is also in agreement with experimental values, though these are not very precise. This success motivates us to also include two-nucleon current contributions that include the meson exchange currents. Additionally, our formalism can also be applied to other, so far poorly described, processes like: or
Orthogonal polynomial approach to calculate the two-nucleon transition operator in three dimensions
No full textWe give a short report on the possibility to use orthogonal polynomials (OP) in calculations that involve the two-nucleon (2N) transition operator. The presented work adds another approach to the set of previously developed methods (described in Phys. Rev. C 81, 034006 (2010); Few-Body Syst. 53, 237 (2012); K. Topolnicki, PhD thesis, Jagiellonian University (2014)) and is applied to the transition operator calculated at laboratory kinetic energy 300MeV. The new results for neutron-neutron and neutron-proton scattering observables converge to the results presented in Few-Body Syst. 53, 237 (2012) and to results obtained using the Arnoldi algorithm (Y. Saad, Iterative methods for sparse linear systems (SIAM Philadelphia, PA, USA 2003)). The numerical cost of the calculations performed using the new scheme is large and the new method can serve only as a backup to cross-check the previously used calculation schemes
Momentum space treatment of inclusive neutrino scattering off the deuteron and trinucleons
No full textSelected (anti)neutrino-induced reactions on H-2, He-3, and H-3 are studied consistently in momentum space for (anti)neutrino energies up to 250 MeV. For most of these processes we provide predictions for the total cross sections, and in the case of the (anti)neutrino-He-3 and (anti)neutrino-H-3 inelastic scattering we compute examples of essential response functions, using the AV18 nucleon-nucleon potential and a single-nucleon weak current operator. For the reactions with the deuteron we comment on relativistic effects in the final-state kinematics and compare two-nucleon scattering states obtained in momentum and coordinate spaces. Our results from momentum space are compared with the theoretical predictions by G. Shen et al. [Phys. Rev. C 86, 035503 (2012)]. The observed disagreement can be attributed to the differences in kinematics and in the weak current operator
Break-up channels in muon capture on ^{3}He
No full textThe μ- +3 He → νμ + n + d and μ- +3 He → νμ + n + n + p capture reactions are studied under full inclusion of final state interactions with the AV18 nucleon-nucleon potential, augmented by the Urbana IX three-nucleon force, and employing the single nucleon weak current operator. We give first realistic estimates of the total capture rates: 544 s-1 and 154 s-1 for the n + d and n + n + p channels, respectively. Our results are compared with the most recent experimental data, finding a rough agreement for the total capture rates, but failing to reproduce the differential capture rates
Break-up channels in muon capture on
No full textThe μ−+2H→νμ+n+n, μ−+3He→νμ+3H, μ−+3He→νμ+n+d, and μ−+3He→νμ+n+n+p capture reactions are studied with various realistic potentials under full inclusion of final-state interactions. Our results for the two- and three-body break-up of He3 are calculated with a variety of nucleon-nucleon potentials, among which is the AV18 potential, augmented by the Urbana IX three-nucleon potential. Most of our results are based on the single-nucleon weak-current operator. As a first step, we tested our calculation in the case of the μ−+2H→νμ+n+n and μ−+3He→νμ+3H reactions, for which theoretical predictions obtained in a comparable framework are available. Additionally, we have been able to obtain for the first time a realistic estimate for the total rates of the muon capture reactions on He3 in the break-up channels: 544 s−1 and 154 s−1 for the n+d and n+n+p channels, respectively. Our results are compared with the most recent experimental data, finding a rough agreement for the total capture rates, but failing to reproduce the differential capture rates
General operator form of the non-local three-nucleon force
No full textThis paper describes a procedure to obtain the general form of the three-nucleon force. The result is an operator form where the momentum space matrix element of the three-nucleon potential is written as a linear combination of 320 isospin-spin-momentum operators and scalar functions of momenta. Any spatial and isospin rotation invariant three-nucleon force can be written in this way and in order for the potential to be Hermitian, symmetric under parity inversion, time reversal and particle exchange, the scalar functions must have definite transformation properties under these discrete operations. A complete list of the isospin-spin-momentum operators and scalar function transformation properties is given
Response Functions and Differential Cross Sections for Neutrino Scattering off 2H
No full textThe need of a better understanding of the weak interaction and the electro-weak unification triggered in the last decades an interest in neutrino scattering off nuclei. Here, we present a study on neutrino-induced reactions off 2H. The cross sections are calculated via the nuclear response functions, which contain the information about the nuclear structure and interactions.45th Congress of Polish Physicists, September 13–18, 2019, Kraków (Cracow), Polandjournal articl
Radiative pion capture in 2H, 3He, and 3H
No full textThe pi(-) + H-2 -> gamma + n + n, pi(-) + He-3 -> gamma + H-3, pi(-) + He-3 -> gamma + n + d, pi(-) + He-3 -> gamma + n + n + p, and pi(-) + H-3 -> gamma + n + n + n capture reactions are studied with the AV18 two-nucleon potential and the Urbana IX three-nucleon potential. We provide for the first time realistic predictions for the differential and total capture rates for all these processes, treating consistently the initial and final nuclear states. Our results are based on the single-nucleon Kroll-Ruderman-type transition operator and concentrate on the full treatment of the nuclear final state interactions. They are compared with older theoretical predictions and experimental data
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