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A P Banford

Bio: A P Banford is an academic researcher. The author has contributed to research in topics: Neutron & Scattering. The author has an hindex of 1, co-authored 1 publications receiving 10 citations.

Papers
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Journal ArticleDOI
01 Mar 1958
TL;DR: The angular distribution of neutrons scattered by protons at effective energies of 96, 130 and 137 Mev and at angles between 19.3° and 78.1° in the centre-of-mass system have been measured using photographic emulsions as mentioned in this paper.
Abstract: The angular distributions of neutrons scattered by protons at effective energies of 96, 130 and 137 Mev and at angles between 19.3° and 78.1° in the centre-of-mass system have been measured using photographic emulsions. The differential cross sections have been normalized to the absolute scale by deducing the energy spectrum of the neutrons. The results confirm that at 130 and 137 Mev the cross sections for scattering at angles within 60° of the forward direction in the centre-of-mass system are less than those for a similar range of angles in the backward direction.

10 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, the two-nucleon system at N 3 LO was considered and the spectral function regularization for the multi-pion exchanges was employed to show that the three pion exchange contribution is negligibly small.

560 citations

Journal ArticleDOI
TL;DR: In this article, the authors presented improved nucleon-nucleon potentials derived in chiral effective field theory up to next to next-next-to-next tonext-leading order, which are able to reduce finite-cutoff artefacts by using an appropriate regularization in coordinate space which maintains the analytic structure of the amplitude.
Abstract: We present improved nucleon-nucleon potentials derived in chiral effective field theory up to next-to-next-to-next-to-leading order. We argue that the nonlocal momentum-space regulator employed in the two-nucleon potentials of previous works (Nucl. Phys. A 747, 362 (2005) and Phys. Rev. C 68, 041001 (2003)) is not the most efficient choice, in particular since it affects the long-range part of the interaction. We are able to significantly reduce finite-cutoff artefacts by using an appropriate regularization in coordinate space which maintains the analytic structure of the amplitude. The new potentials do not require the additional spectral function regularization employed in (Nucl. Phys. A 747, 362 (2005)) to cut off the short-range components of the two-pion exchange and make use of the low-energy constants ci and di determined from pion-nucleon scattering without any fine tuning. We discuss in detail the construction of the new potentials and convergence of the chiral expansion for two-nucleon observables. We also employ a simple approach for estimating the theoretical uncertainty in few-nucleon calculations from the truncation of the chiral expansion that replaces previous reliance on cutoff variation.

283 citations

Journal ArticleDOI
TL;DR: In this paper, Epelbaum et al. presented improved nucleon-nucleon potentials derived in chiral effective field theory up to next-to-next-tonext-leading order, which are able to significantly reduce finite-cutoff artefacts by using an appropriate regularization in coordinate space.
Abstract: We present improved nucleon-nucleon potentials derived in chiral effective field theory up to next-to-next-to-next-to-leading order. We argue that the nonlocal momentum-space regulator employed in the two-nucleon potentials of Refs. [E. Epelbaum, W. Gloeckle, U.-G. Mei{\ss}ner, Nucl. Phys. A747 (2005) 362], [D.R. Entem, R. Machleidt, Phys. Rev. C68 (2003) 041001] is not the most efficient choice, in particular since it affects the long-range part of the interaction. We are able to significantly reduce finite-cutoff artefacts by using an appropriate regularization in coordinate space which maintains the analytic structure of the amplitude. The new potentials do not require the additional spectral function regularization employed in Ref. [E. Epelbaum, W. Gloeckle, U.-G. Mei{\ss}ner, Nucl. Phys. A747 (2005) 362] to cut off the short-range components of the two-pion exchange and make use of the low-energy constants c_i and d_i determined from pion-nucleon scattering without any fine tuning. We discuss in detail the construction of the new potentials and convergence of the chiral expansion for two-nucleon observables. We also introduce a new procedure for estimating the theoretical uncertainty from the truncation of the chiral expansion that replaces previous reliance on cutoff variation.

263 citations

Journal ArticleDOI
TL;DR: Using the covariant spectator theory (CST), the authors presented two one-boson-exchange kernels that have been successfully adjusted to fit the 2007 world$ data (containing 3788 data) below 350 MeV.
Abstract: Using the covariant spectator theory (CST), we present two one-boson-exchange kernels that have been successfully adjusted to fit the 2007 world $\mathit{np}$ data (containing 3788 data) below 350 MeV. One model (which we designate WJC-1) has 27 parameters and fits with a ${\ensuremath{\chi}}^{2}/{N}_{\mathrm{data}}=1.06$. The other model (designated WJC-2) has only 15 parameters and fits with a ${\ensuremath{\chi}}^{2}/{N}_{\mathrm{data}}=1.12$. Both of these models also reproduce the experimental triton binding energy without introducing additional irreducible three-nucleon forces. One result of this work is a new phase-shift analysis, updated for all data until 2006, which is useful even if one does not work within the CST. In carrying out these fits we have reviewed the entire database, adding new data not previously used in other high precision fits and restoring some data omitted in previous fits. A full discussion and evaluation of the 2007 database is presented.

133 citations

Journal ArticleDOI
TL;DR: In this article, the authors presented a successful fit to neutron-proton and protonproton scattering data below pion production threshold using the delta-shell representation, which includes data within the years 1950 to 2013.
Abstract: Using the delta-shell representation we present a successful fit to neutron-proton and proton-proton scattering data below pion production threshold. A detailed overview of the theory necessary to calculate observables with this potential is presented. A new data selection process is used to obtain the largest mutually consistent data base. The analysis includes data within the years 1950 to 2013. Using 46 parameters we obtain chi^2/Ndata = 1.04 with Ndata = 6713 including normalization data. Phase shifts with error bars are provided.

110 citations