Momentum distributions and short-range correlations in the deuteron and He3 with modern chiral potentials

Abstract

We study momentum distributions and short-range correlation probabilities in A=2 and A=3 systems. First, we show results with phenomenological and meson-theoretic two-and three-nucleon forces to verify consistency with previous similar studies. We then apply most recent high-quality chiral nucleon-nucleon potentials up to fifth order in the chiral expansion together with the leading chiral three-nucleon force. Predictions are examined in the context of a broader discussion of short-range correlation probabilities extracted from analyses of inclusive electron scattering data, addressing the question of whether modern interactions can be reconciled with the latter.The analysis of Ref.[13] highlights non-localities in the tensor force as the source of differences in SRC among the various predictions, and suggests that such model dependence should be taken into account, as it may impact SRC considerations for heavier nuclei, see comments just below Eq. (2). At this point, it is appropriate to recall that the presence of non-locality in the tensor force has been found since a long time to be a desirable feature in nuclear structure calculations. (For a discussion on the impact of non-locality in the one-pion exchange, see, for instance, Refs. [20][21][22].)This paper contains updates and major extensions of the work of Ref.[13], presenting a simultaneous study of momentum distributions in the deuteron and in 3 He. First, we calculate the deuteron momentum distribution using the most recent chiral 2N potentials from Ref. [23], from leading to fifth chiral order. These interactions are better and more consistent than the ones of Refs. [17][18][19] used in Ref.[13], because the same power counting scheme and cutoff procedures are used at each order. In addition, the πN low-energy constants (LECs) are the very accurate ones determined in the Roy-Steiner analysis of Ref. [24]. The uncertainty associated with these LECs is sufficiently small that variations within their errors have negligible impact on the construction of the potentials, which are non-local and of soft nature. A point worth mentioning is that these 2N forces can predict a triton binding energy around 8.1 MeV, leaving only very small room for three-nucleon (3N) forces.We then proceed to consider the single-nucleon (1N) and 2N momentum distributions in 3 He using the phenomenological AV18 and the meson-theoretic CDBonn potentials, alone or augmented by 3N forces, namely the Urbana IX (UIX) model [25] in conjunction with AV18, and the Tucson-Merlbourne (TM) [26] 3N force in conjunction with CDBonn. This will allow us to quantify the 3N force contributions within the framework of these older forces. To verify our calculations, results obtained with the AV18 and AV18/UIX potential models will be compared with the previous studies of Refs. [27][28][29].Having established a reliable baseline, we shift our focus to the more novel aspects of this work, namely the most recent high precision chiral 2N potentials [23] and corresponding chiral 3N force. The main motivat...

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