Determination of the deuteron asymptotic D- to S-state ratio by a padé-approximant technique

Horáček, J.; Bok, J.; Krasnopolskij, V.M.; Kukulin, V. I.

doi:10.1016/0370-2693(86)90205-4

Cited by 20 publications

(2 citation statements)

References 17 publications

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“…A number of groups have made use of this method, the difference mainly lying in the way they do the extrapolation. We mention here the determination of Londergan, Price, and Stephenson 4 with \0 3 rj p =26.7 ± 1.4, of Horacek et al 5 with lO 3^ =27.0 ±0.6, and of Borbely et al 6 with lO 3^ =26.7 ±0.4.…”

Section: U~-a S De~r /R W~-a D D E~r /R (\+3r/r + 3r 2 /R 2 )mentioning

confidence: 97%

Determination of the Residue at the Deuteron Pole in annpPhase-Shift Analysis

et al. 1988

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In an energy-dependent phase-shift analysis of all low-energy np scattering data below 7^ -30 MeV we reach ^VTVDF^I.I, where /VDF is the number of degrees of freedom. In our fit we determine the Smatrix elements in the coupled 3 Si + 3 Z>i channels, which allows us to compute the residue at the deuteron pole. Expressed in terms of the deuteron parameters, we find for the asymptotic normalization of the 3 Si state ^5=0.8838(4) fm~1 /2 and for the asymptotic D/S ratio 77=0.027 12(22). Compared with other determinations, there seems to be some indication for the presence of closed isobar channels and/or energy-dependent potentials in the deuteron system. PACS numbers: 21.40.+d, 13.75.Cs, 27.10.+h For several years now there has been a renewed interest in the precise determination of the deuteron parameters. These serve as an important constraint on the description of the np interaction. Special attention 1_12 has been given to the asymptotic ZMo-S-state ratio r\ and, more recently, to the asymptotic normalization As of the S state. 13,14 Most of the determinations of these two quantities come from analyses of either pd elastic scattering or (d,p) stripping reactions and ip,d) pickup reactions on various nuclei. Some discrepancies between the various determinations have shown up, especially for the value of r/.In this Letter we present a very accurate determination of r\ and As with the help of an energy-dependent phase-shift analysis of all np scattering data below 7^ -30 MeV. In this way the values for As and r\ are obtained purely from the two-body np scattering data, thereby circumventing the typical many-body problems arising in many of the other analyses.In our phase-shift analysis the scattering matrix S and the K matrix are determined, where S s= (\+iK)(\ -iK)~x.To study the deuteron, special attention is given to the coupled 3 S\ + ^D\ channels. Time-reversal invariance allows us to choose the relative phases between the 3 S\ and the 3 D\ channel such that the S and K matrices are symmetric above as well as below the threshold £=0, with E = (k 2 + M?) U2 +(k 2 + Mt) l/2 -(M p + M n ) the cm. energy, k the relative cm. momentum, and M p and M n the proton and neutron mass, respectively. Unitarity requires that above the threshold (E > 0, k > 0) the S matrix is unitary, and therefore the K matrix Hermitean. Below the threshold (E < 0), the S matrix is real and the K matrix purely imaginary. The S and K matrices can be diagonalized simultaneously by a real, orthogonal matrix cose" -sine [sine cose-J'where e is the Blatt and Biedenharn 15 mixing parameter.The eigenvalues of S and K are ^=exp(2/^) and Kx=tand\ with X=0 or 2, and 8x the Blatt and Biedenharn eigenphase shifts. Next we introduce the projection operators P\*=P 2 on the scattering eigenstates, where Po+Pi-l and cos 2 e~ cosesine*[cose-sine sin z 6 J This allows us to write S =2ASJ 1 /\ and K^Y^xK^P^.The existence of the deuteron at 16 E = -B = -2.224575(9) MeV means that in the complex momentum plane the eigenvalue So has a pole at k =m, and so at ...

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Section: U~-a S De~r /R W~-a D D E~r /R (\+3r/r + 3r 2 /R 2 )mentioning

confidence: 97%

Determination of the Residue at the Deuteron Pole in annpPhase-Shift Analysis

et al. 1988

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“…[37]; g ) Ref. [38] Having chosen all the parameters of the effective Hamiltonian H ef f in the NN channel, the deuteron two-phase structure can be derived with no additional parameters. In Table II the main static properties of the deuteron as emerging from the above NN-model are compared to experiment and to predictions of other modern NN-force models.…”

Section: The Effective N N -Interaction In the Dressed-bag State Modelmentioning

confidence: 99%

A Six-Quark Dressed-Bag Description of np→dγ Radiative Capture

Kaskulov

Grabmayr

Kukulin

2003

Int. J. Mod. Phys. E

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The radiative capture process np → dγ is considered within the framework of a recently developed six-quark dressed-bag model for the nucleon-nucleon interaction. The calculations presented here include both the nucleon current and the meson-exchange current contributions. The latter uses short-range hadronic form factors for the pion exchange currents consistent with the soft cut-off parameter Λ πN N from the N N -potential. Contributions of the pion exchange current and ∆-isobar current to the total cross section still cannot explain the discrepancy between the theoretical and experimental cross sections. Possibilities for new types of meson exchange currents associated with chiral fields inside multi-quark dressed-bag states in nuclei are discussed.

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Three-body coulomb effects in one-particle transfer reactions

Kajumov¹,

Mukhamedzhanov²,

Yarmukhamedov³

et al. 1990

Z. Physik A - Atomic Nuclei

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The behaviour of the DWBA amplitudes in the vicinity of the nearest singularity in the cos 0-plane for the neutron and charged particle transfer reactions is investigated. It is shown that Coulomb interactions transform the pole singularity into a branch point. The main singular terms of the complete and the post-approximation DWBA cross sections are compared with the exact threebody results. They differ only by the Coulomb renormalization factors (CRF), which define the renormalization of the singularity strength generated by the Coulomb interactions. In the case of neutron transfer it is shown that the complete DWBA and exact CRFs practically coincide and slightly differ from CRF obtained in postapproximation DWBA. For charged particle transfer reactions the exact CRF may differ considerably from the one obtained in DWBA and especially in the post-approximation DWBA. Our conclusion therefore is that in order to obtain a reliable value of the vertex constant by extrapolating the differential cross-section to the nearest singularity, the exact three-body approach should be used.

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Determination of the deuteron asymptotic D- to S-state ratio by a padé-approximant technique

Cited by 20 publications

References 17 publications

Determination of the Residue at the Deuteron Pole in annpPhase-Shift Analysis

Determination of the Residue at the Deuteron Pole in annpPhase-Shift Analysis

A Six-Quark Dressed-Bag Description of np→dγ Radiative Capture

Three-body coulomb effects in one-particle transfer reactions

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