Near-threshold production of a 0(980) mesons in πN and NN collisions and a 0-f 0 mixing

Abstract

We consider near-threshold a 0 (980)-meson production in πN and N N collisions. An effective Lagrangian approach with one-pion exchange is applied to analyze different contributions to the cross section for different isospin channels. The Reggeon exchange mechanism is also evaluated for comparison. The results from πN reactions are used to calculate the contribution of the a 0 meson to the cross sections and invariant KK mass distributions of the reactions pp → pnK +K 0 and pp → ppK + K − . It is found that the experimental observation of a + 0 mesons in the reaction pp → pnK +K 0 is much more promising than the observation of a 0 0 mesons in the reaction pp → ppK + K − . Effects of isospin violation in the reactions pN → da 0 , pd → 3 He/ 3 H a 0 , and dd → 4 He a 0 , which are induced by a 0 (980)f 0 (980) mixing, are also analyzed.

Baryon-baryon and baryon-antibaryon interaction amplitudes in the spin-momentum operator expansion method

“…To calculate the amplitude squared |A| 2 , one can use the expressions for the one-loop diagram given by eqs. (86), (91), (89) and (90). For the 1 L J state, one has…”

“…pentaquarks [56,57,58,59,60,61,62,63]). COSY at the Research Center Jülich is providing a wealth of data on meson production in proton-proton inelastic scattering [64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,<...>…”

Near-threshold production of a0(980)-mesons in the reaction $\rm {pp \rightarrow d K^ + \bar{K^0}}$

“…4) and conclude that KK pairs from background will predominantly be in a P -wave, while in the case of a 0 decay it will be produced in the S-wave (see also Section 2 and Ref. [30]). According to the long-dashed line in Fig.…”

Manifestation of thea00(980)−f0(980)mixing in the reactionAchasov1, Shestakov2 2004Phys. Rev. D

“…Moreover, the reactions π ± N → ηπ 0 (N, (980) − f 0 (980) mixing could be detected, were considered in detail, and effects of violation of isospin invariance caused by this mixing were estimated in the ηπ 0 and ππ mass spectra and differential cross sections [3]. Recently, interest in the a 0 0 (980) − f 0 (980) mixing was renewed, and its possible manifestations in various reactions are intensively discussed in the literature [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. However, this mixing has not unambiguously been identified yet in corresponding experiments.…”