New anomalous trajectory in Regge theory

Abstract

We show that a new Regge trajectory with \alpha_{f_1} (0) \approx 1 and slope \alpha_{f_1}'(0) \approx 0 explains the features of hadron-hadron scattering and photoproduction of the rho and phi mesons at large energy and momentum transfer. This trajectory with quantum numbers P = C = +1 and odd signature can be considered as a natural partner of the Pomeron which has even signature. The odd signature of the new exchange leads to contributions to the spin-dependent cross sections, which do not vanish at large energy. The links between the anomalous properties of this trajectory, the axial anomaly and the flavor singlet axial vector f_1 (1285) meson are discussed.Comment: 20 pages, REVTeX, 8 figures (9 eps files), version to appear in Phys. Rev.

On a possible manifestation of f1 trajectory in J/ψ photoproduction

“…[11] where it is assumed that the intercept of this trajectory is equal to 1, in agreement with the low x behavior of the spindependent deep inelastic structure function g 1 (x, Q 2 ) ∼ 1/x α with α = 0.9 ± 0.2. Moreover it is assumed that the slope of the trajectory is close to zero, which is in agreement with large t behavior of elastic pp scattering.…”

“…It should be noted that our prediction is based on the assumption of the zero slope of the f 1 trajectory discussed in Ref. [11], in which two physical grounds for almost zero slope of the f 1 trajectory were given as (i) there is a nonvanishing -4 -contribution to the elastic pp scattering at high energy due to such f 1 trajectory and (ii) f 1 -meson exchange is deeply related to the axial anomaly which is associated with the instanton fluctuations whose space scale is much smaller than the scale of confinement. On the contrary, if the slope of f 1 trajectory is finite, we expect strong decreasing of its contribution both in s-dependence of the σ tot , dσ/dt(t = 0) and in t-dependence of dσ/dt(t = 0) at large s and in consequence, any deviation from the standard Pomeron model for all the polarization observables discussed in our paper would disappear.…”

“…However, so far the study of the unnatural parity exchange trajectories at high energy has not been done widely. Recently, an interesting analysis for testing the new f 1 -trajectory associated with the axial vector meson exchange was done by Kochelev et al [11], in which the slope of the trajectory was taken to be almost zero. It is very interesting to test the effect of this trajectory even for heavy vector meson J/ψ photoproduction.…”

“…To test the effect of the f 1 trajectory contribution alone, it might be advantageous to use the other light vector meson (ρ, φ) photoproductions discussed in Ref. [11]. However, if non-trivial interference effects in spin variables predicted in this work could be observed in experiment, it will not only be just a supplementary support for the f 1 trajectory but also a good test of the hard Pomeron contribution as well, because the hard Pomeron is important only in the J/ψ photoproductions.…”

“…For the f 1 NN vertex, we use the flavor singlet axial vector form factor which is fixed from fitting to elastic pp scattering at high √ s and large |t| [11]. (See also [15].…”