Investigation of the processes e + e − → 2 (π+π−π0) and e + e − → 3 (π+π−) with the aid of the CMD-3 detector

Abstract

Investigation of the Processes e e e + e e e -→ 2 → 2 → 2 (π + ππ 0 ) and e e e + e e e -→ 3 → 3 → 3 (π + π -) with the Aid of the CMD-3 Detector Abstract-The cross sections for the processes e + e − → 2(π + π − π 0 ) and e + e − → 3(π + π − ) at c.m. energies in the range of 1.5-2 GeV were measured with the aid of the CMD-3 detector at the VEPP-2000 collider of the Budker Institute of Nuclear Physics (Novosibirsk, Siberian Branch, Russian Academy of Sciences). The integrated luminosity in the respective experiment was 22 pb −1 .

Interaction of real and virtual pp¯ pairs in J/ψ→p

“…The enhancement near the pp threshold is also observed in the decays J/ψ(ψ ) → ppπ 0 (η) [5][6][7], J/ψ(ψ ) → ppω(γ) [5,[8][9][10][11]. The sharp peak in the vicinity of N N threshold has been observed in the cross sections of several processes, i.e., e + e − → 6π [12][13][14][15][16] and J/ψ → γη π + π − [17]. These observations led to numerous speculations about a new resonance [5], pp bound state [18][19][20], or even a glueball state [21][22][23] with the mass about double proton mass.…”

Real and virtualNN¯pair production near the threshold

“…This distribution was analyzed for shows the contribution of non-NN channels. The data for total 6π production are calculated from BABAR [14] and CMD-3 [15,16] data. 3 (π + π − ) and 2 π + π − π 0 channels are taken into account,…”

“…The inelastic cross section can be expressed in terms of the Green's function of the Schrï¿oedinger equation in the presence of an optical potential. First of all, we are interested in the processes e + e − → 3 (π + π − ) and e + e − → 2 (π + π − π 0 ) because the cross sections of 6π production have a sharp dip near the pp threshold [14][15][16], and this phenomenon is not well understood yet. This feature is expected to be a consequence of the interaction of virtual nucleons, because other contributions should be smooth functions in the energy region under consideration.…”

Fine structure of the cross sections of e+e− annihilation near the thresholds of pp¯ and nnMilstein1, Salnikov2 2018Nuclear Physics A242321View full textAdd to dashboardCite

“…In a set of experiments it has been shown that the cross sections of e + e − annihilation into pp [1][2][3][4], nn [5] and mesons [6][7][8][9] near the thresholds of N N production reveal the unusual behavior. Namely, in this region the cross sections strongly depend on the energy.…”