ππPartial-Wave Analysis from Reactionsπ+p→π+

Abstract

H. Yuta, University of Rochester Report No. UR-875-271, 1969 (unpublished). 9~ similar calculation performed by F. Bomse and R. Moses, Phys. Rev. 3, 2163 (1968), also predicts a low-mass Kfa enhancement. Also see the analogous work pertaining to the Ai in F. Winkelmann, R. Mickens, and H. J. Lubatti, Nucl. Phys. m, 535 (1971), and in Ref. 3. "'The quantities da/dt jeXp were calculated in the manner described in Ref. 3. "~h e s e values of m a s s and width a r e similar to those which were found to describe the Q + signal produced in 12.7-GeV/c K'p interactions, s e e M. Farber et al., Phys. Rev. D 1, 78 (1970). We have widened the rcE to account for the different widths observed in Fig. 4. When fitting m a s s spectra we use a distorted Breit-Wigner: The simple Breit-Wigner form i s multiplied by the polynomial employed to describe the background.We present results of an energy-dependent phase-shift analysis for aa energies between 550 and 1150 MeV from reactions a+p -n+rr-A++ and a+p -K+K-A++ a t 7.1 GeV/c. The

Chiral symmetry amplitudes in the S-wave isoscalar and isovector channels and the σ, f0(980), a0(980) scalar mesons

“…We show in the figure the results for two values of the cut off energy Λ = 1.1 and 1.2 GeV ( Λ = (q 2 max + m 2 K ) 1/2 ) We can see that the agreement with the experiment [1,[38][39][40][41][42][43][44][45] is rather good up to values of √ s = 1.2 GeV . From there on discrepancies with experiment start to appear, but this should be expected because of the opening of the ηη channel, the increasing importance of the 4π channel and the possible influence of higher resonances which cannot be considered as meson-meson states.…”

“…However, the f 0 (980) (also called S * , I G (J P C ) = 0 + (0 ++ )), and the a 0 (980) (also called δ, I G (J P C ) = 1 − (0 ++ )) mesonic states are well established experimentally, although there is still debate around their decay widths and particularly about their nature. Following the discovery of the f 0 [1], and a 0 [2], several proposals were made about the nature of these states: qq states [3][4][5][6][7][8][9][10], multiquark states [11,12] or KK molecules [13,14,15,16]. Other works argue against the qq nature of the states [17].…”

Chiral extrapolations of the ρ(770) meson in Nf=2+1 lattice QCD simulations

“…Phase shifts obtained for the minimization strategy (a) described in the text. Lattice data included in the fit [26-28, 30, 34] are shown in red, together with their extrapolations to the physical point (red and dashed-blue curves), and in comparison to the experimental data (blue) [58]. In all plots, solid (dashed) lines show the results using the two-channel SU ( .o.f with respect to the lattice data is given for every strategy.…”

Construction of high-qualityNNpotential models

“…No such meson is listed by the Particle Data Group [17]; however, a recent analysis of the πN → π + π − N reaction [19] provides evidence for a scalar-isoscalar resonant state 0 ++ (750). In the Nijmegen potentials the ǫ meson corresponds to a broad meson (see below) where the pole in its propagator is chosen to correspond to the pole position in the complex energy plane of the isoscalar ππ S wave [20]. Here we will retain the name of ǫ meson.…”