Baryon polarization in low-energy unpolarized meson-baryon scattering

Abstract

We compute the polarization of the final-state baryon, in its rest frame, in low-energy meson-baryon scattering with unpolarized initial state, in Unitarized BChPT. Free parameters are determined by fitting total and differential cross-section data (and spin-asymmetry or polarization data if available) for pK − , pK + and pπ + scattering. We also compare our results with those of leading-order BChPT.

Low-energy reactionsK−p→Σ0π0,Λπ0Zhong1, Zhao2 2013Phys. Rev. C123160View full textAdd to dashboardCite

“…Around P K − = 400 MeV/c (W ≃ 1.52 GeV), Λ(1520)D 03 is responsible for the sharp resonant peak in the total cross section. The tail of the partial cross section of Λ(1520)D 03 can extend to the low energy region P K − ∼ 300 MeV/c (W ∼ 1.49 GeV), and to the higher energy region P K − ∼ 750 MeV/c (W ∼ 1.68 GeV), which is consistent with the analysis of [34].…”

“…The important role of u channel in these reactions is also predicted with the BχPT [34] and UχPT approaches [21,30]. In K − p →K 0 n, there are no uchannel contributions, while the t channel is crucial to give the correct shapes of the differential cross sections.…”

“…Theoretically, (i) the mass spectroscopes were predicted in various quark models [4][5][6][7][8][9][10][11][12][13], large N c QCD approach [12,13] and lattice QCD etc [14,15]; (ii) the strong decays were studied within different models [4,[16][17][18][19]; (iii) the properties of the individual resonances, such as Λ(1405), Λ(1670) and Λ(1520), were attempted to extract from the K − p scattering data with UχPT approaches [20][21][22][23][24][25][26][27][28][29][30][31][32][33], BχPT approaches [34], K-matrix methods [35,36], large-N c QCD method [37], meson-exchange models [38][39][40], quark model approaches [41,42], dispersion relations [43,44], and the other hadronic models [45][46][47]…”

Polarized pK- scattering in Unitary Baryon Chiral Perturbation Theory

“…The tree-level scattering amplitudes so obtained differ from those for N π scattering [15] only in their flavor coefficients. The CMF partial waves for tree-level s-channel decuplet exchange given in [23] are used here without modification. We discuss here u-channel decuplet-baryon exchange, which was not given explicitly in [23], and below similar results are presented for s-and u-channel nonet-baryon and t-channel vector-meson exchange amplitudes.…”

“…A unitarization method dealing directly with the chiral effective theory T -matrix was introduced in [15,16], drawing elements from the N/D method of [17] and from analogous approaches in the meson sector [18,19]. This Unitary Baryon Chiral Perturbation Theory (UBChPT) has been shown to give good descriptions of cross-section data in N K processes [16,[20][21][22], and in N π scattering beyond the ∆ resonance peak [15,23].…”