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Witsch, W. von; Ruan, Xichao; Witała, H.

doi:10.1103/physrevc.74.014001

Cited by 31 publications

(25 citation statements)

References 17 publications

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“…As a consequence, the value of the scattering length a nn = ⎯16.5(9) fm [32] found not long ago in the nd decay reaction, unlike the value a nn = -18.7(7) fm [33], con tradicts the results of analysis of the 3 H and 3 He nuclei binding energies difference. …”

Section: Charge Symmetry Breaking Of Nuclear Forces In Three Nucleon mentioning

confidence: 58%

“…An analysis of the recent experimental results yields two scattering length val ues: a nn = -16.5(9) fm [32] and a nn = -18.7(7) fm [33]. An essential discrepancy in these a nn values is connected both with the difficulty in setting up exper iments on measurement of the reaction yield for such reactions as π -+ d → γ + n + n and n + d → p + n + n and in the theoretical analysis of such experiments.…”

Section: Low Energy Parameters Of Nucleon-nucleon Interactionmentioning

confidence: 99%

“…Using experimental value (22) for the difference of 3 H and 3 He nuclei binding energies and values (17) and (25) of the quantities ε pp and Δ EM , according to formula (31) we obtain the virtual neutron-neutron level energy (32) which corresponds to the wave number (33) According to formulas (8), (9), (12), and (21), using nn system wave number (33), we obtain the neutron-neu tron scattering length a nn and the effective radius r nn , According to formulas (15) and (34), (35), the dif ference between the low energy parameters of protonproton and neutron-neutron interaction is (36) (37) which well agrees with Δa CSB ≈ 1 fm and Δr CSB ~ 0.02 fm obtained in [7][8][9] under the assumption that the charge symmetry breaking of nuclear forces is determined by the exchange of mixed ρω mesons. Values (34) and (35) obtained here are in a very good agreement with the experimental values for a nn and r nn , (39) found in [35] using the reaction π -+ d → γ + n + n.…”

Section: Determination Of Low Energy Parameters Of Neutron-neutron Scmentioning

confidence: 99%

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Mirror nuclei 3H and 3He binding energies difference and low energy parameters of neutron-neutron scattering

Бабенко

Petrov

2015

Phys. Part. Nuclei Lett.

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A relationship between the binding energy difference for the mirror nuclei 3 H and 3 He and the low energy parameters of neutron-neutron and proton-proton scattering is established. The experimental values for the difference of 3 H and 3 He binding energies and the low energy proton-proton scattering parameters are used to obtain the values for the neutron-neutron scattering length a nn = -18.38(55) fm and the effective range r nn = 2.84(4) fm. The calculated neutron-neutron scattering length is in good agreement with one of the two well known and differing experimental values of this quantity.

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Section: Charge Symmetry Breaking Of Nuclear Forces In Three Nucleon mentioning

confidence: 58%

Section: Low Energy Parameters Of Nucleon-nucleon Interactionmentioning

confidence: 99%

Section: Determination Of Low Energy Parameters Of Neutron-neutron Scmentioning

confidence: 99%

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Mirror nuclei 3H and 3He binding energies difference and low energy parameters of neutron-neutron scattering

Бабенко

Petrov

2015

Phys. Part. Nuclei Lett.

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“…± 0.30(th.) fm from the π − d → nnγ process [13] and a nn = −18.7 ± 0.6 fm [14], −16.06 ± 0.35 fm [15] and −16.5 ± 0.9 fm [16] from the nd → nnp process. As seen, the values of a nn have significant errors compared to that of a np , and the center values do not seem to converge yet.…”

Section: Introductionmentioning

confidence: 99%

Low energy proton-proton scattering in effective field theory

et al. 2007

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Low energy proton-proton scattering is studied in pionless effective field theory. Employing the dimensional regularization and MS and power divergence subtraction schemes for loop calculation, we calculate the scattering amplitude in 1 S 0 channel up to nextto-next-to leading order and fix low-energy constants that appear in the amplitude by effective range parameters. We study regularization scheme and scale dependence in separation of Coulomb interaction from the scattering length and effective range for the S-wave proton-proton scattering.PACS(s): 11.10.Gh, 13.75.Cs.1 mailto:sando@color.skku.ac.kr 1 IntroductionEffective field theories (EFTs), which provide us a systematic perturbative scheme and a model-independent calculation method, have become a popular method to study hadronic reactions with and without external probes at low and intermediate energies.(See, e.g., Refs. [1, 2, 3, 4, 5] for reviews.) At very low energies, the Coulomb interaction becomes essential for the study of reactions involving charged particles. The first consideration of the Coulomb interaction in a pionless EFT was done by Kong and Ravndal (KR) for low energy S-wave proton-proton (pp) scattering [6,7]. They calculated the pp scattering amplitude up to next-to leading order (NLO). For loop calculations, they employed dimensional regularization with minimum subtraction (MS) scheme and so called power divergence subtraction (PDS) scheme suggested by Kaplan, Savage and Wise [8,9]. Then KR estimated a scattering length a(µ) for the pp scattering after separating off the Coulomb correction where µ is the scale for dimensional regularization. The leading order (LO) result of a(µ) was almost infinite at µ = m π where m π is the pion mass [6]. In addition, the LO a(µ) was highly dependent on the value of µ. Including the NLO correction, they obtained a(µ = m π ) = −29.9 fm [7] which is comparable to the value of the scattering length a np in the np channel, a np = −23.748 ± 0.009 fm 2 . The value of a(µ) deduced after separating the Coulomb and strong interactions is particularly important in the study of isospin breaking effects in S-wave NN interaction [11,12]. The accurate value of a np is well known as quoted above, while the values of the scattering length in the nn channel (a nn ) and in the pp channel (a pp ) still have considerable uncertainties.There exists no direct nn scattering experiment because of the lack of free neutron target. The values of a nn have been deduced from the experimental data of π − d → nnγ and nd → nnp reactions. Recent publications suggest a nn = −18.50 ± 0.05(stat.) ± 0.44(syst.) ± 0.30(th.) fm from the π − d → nnγ process [13] and a nn = −18.7 ± 0.6 fm [14], −16.06 ± 0.35 fm [15] and −16.5 ± 0.9 fm [16] from the nd → nnp process. As seen, the values of a nn have significant errors compared to that of a np , and the center values do not seem to converge yet.

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“…Even a dedicated experiment was performed in order to look for a hypothetical 1 S 0 nn bound state [22] in which the spectrum of the proton going in forward direction has been measured with the aim of a precise determination of its high energy region. The negative result of [22] showed that the nd reaction is not suitable for such a study.…”

Section: Discussion and Further Experimental Informationmentioning

confidence: 99%

Thennquasifreendbreakup cross section: Discrepancies with theory and implications for the1

Witała

Glöckle

2011

Phys. Rev. C

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Large discrepancies between quasi-free neutron-neutron (nn) cross section data from neutron-deuteron (nd) breakup and theoretical predictions based on standard nucleon-nucleon (NN) and three-nucleon (3N) forces are pointed out. The nn 1 S 0 interaction is shown to be dominant in that configuration and has to be increased to bring theory and data into agreement. Using the next-to-leading order (NLO) 1 S 0 interaction of chiral perturbation theory (χPT) we demonstrate that the nn QFS cross section only slightly depends on changes of the nn scattering length but is very sensitive to variations of the effective range parameter.In order to account for the reported discrepancies one must decrease the nn effective range parameter by about ≈ 12% from its value implied by charge symmetry and charge independence of nuclear forces.

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Neutron-neutron final-state interaction in theH2(n,p)2

Cited by 31 publications

References 17 publications

Mirror nuclei 3H and 3He binding energies difference and low energy parameters of neutron-neutron scattering

Mirror nuclei 3H and 3He binding energies difference and low energy parameters of neutron-neutron scattering

Low energy proton-proton scattering in effective field theory

Thennquasifreendbreakup cross section: Discrepancies with theory and implications for the1

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