Formation of σ mesic nuclei in (d, t) and (d,3He) reactions

Abstract

We explore the possibility to observe an enhanced 2π correlation in the scalar iso-scalar (σ) channel in nuclei by (d,t) and (d, 3 He) reactions to obtain new information on the partial restoration of chiral symmetry in the nuclear medium. The sensitivity of the reaction spectra on the change of the chiral condensate in the nuclear medium is examined.

Formation of mesic nuclei by reactions

“…In order to regularize the divergence, we add an extra 5 MeV width to the ImΣ σ in all the bound states in the following calculations. Figure 4 shows a series of ρ nℓ for the ℓ = 0 bound states in 208 Pb for the C = 0.3 case [18]. As seen in the figure, the spectral functions for the deeply bound states have a prominent peak around ω ∼ 2m π .…”

“…The detail discussions are given in Ref. [18]. The appearance of the narrow states at the low energies gives also strong enhancement of the sigma production rate in nucleus around the two pion threshold, which is expected to be seen in the (γ,p) reaction.…”

“…In this line hadronic bound systems have been investigated in various chiral models [6,7,[15][16][17][18][19][20].…”

“…This is associated with a conceivable reduction of the sigma mass and width in medium. Therefore, there might be a chance to create the σ mesic nuclei with relatively small widths, if deeply bound states are formed in heavy nuclei [18]. It has been also found difficult, in the (d,t) or (d, 3 He) reactions, to observe the enhancement near the 2π threshold due to the large distortion effects [18].…”

“…Therefore, there might be a chance to create the σ mesic nuclei with relatively small widths, if deeply bound states are formed in heavy nuclei [18]. It has been also found difficult, in the (d,t) or (d, 3 He) reactions, to observe the enhancement near the 2π threshold due to the large distortion effects [18]. In this paper, we explore the possibility of production of the σ-mesic nuclei by the photon-induced reactions, expecting that the 'transparency' of the (γ,p) reactions enables us to observe the enhancement of the spectral function near the 2π threshold caused by the partial restoration of chiral symmetry in the medium.…”