A classical Odderon in QCD at high energies

We show that the weight functional for color sources in the classical theory of the Color Glass Condensate includes a term which generates Odderon excitations. Remarkably, the classical origin of these excitations can be traced to the random walk of partons in the two dimensional space spanned by the SU(3) Casimirs. This term is naturally suppressed for a large nucleus at high energies.Comment: 19 pages. No figur

Elastic pppp and pˉp\bar pp scattering in the models of unitarized pomeron

Elastic scattering amplitudes dominated by the Pomeron singularity which obey the principal unitarity bounds at high energies are constructed and analyzed. Confronting the models of double and triple (at $t=0$) Pomeron pole (supplemented by some terms responsible for the low energy behaviour) with existing experimental data on $pp$ and $\bar pp$ total and differential cross sections at $\sqrt{s}\geq 5$ GeV and $|t|\leq 6$ GeV$^{2}$ we are able to tune the form of the Pomeron singularity. Actually the good agreement with those data is received for both models though the behaviour given by the dipole model is more preferable in some aspects. The predictions made for the LHC energy values display, however, the quite noticeable difference between the predictions of models at $t\approx -0.4$ GeV$^{2}$. Apparently the future results of TOTEM will be more conclusive to make a true choice.Comment: Revtex4, 8 pages, 5 figures. Text is improved, no changes in figures and conclusions. Version to be published in Phys. Rev.

The Missing Odderon

In contrast to theoretical expectations, experimental results at sqrt(s)=200 GeV for the reaction gamma p --> pi0 X show no evidence for odderon exchange. The upper limit on the cross section is an order of magnitude smaller than the theoretical estimate. It is argued that chiral symmetry leads to a large suppression, taking the thoeretical estimates well below the data. Two additional arguments are presented which may decrease the theoretical estimate further. The calculations are more sensitive to the assumptions made in evaluating the hadronic scattering amplitude than in the processes considered previously and lattice gauge calculations indicate that the odderon intercept may be appreciably lower than usually assumed. These two latter effects are particularly relevant for the reactions gamma p --> f2(1270)X and gamma p --> a2(1320)X for which the data upper limits are also below the theoretical predictions, but not so dramatically as for gamma p --> pi0 X.Comment: 12 pages, 3 figure

Heisenberg's Universal (lns)**2 Increase of Total Cross Sections

The (lns)**2 behaviour of total cross-sections, first obtained by Heisenberg 50 years ago, receives now increased interest both on phenomenological and theoretical levels. In this paper we present a modification of the Heisenberg's model in connection with the presence of glueballs and we show that it leads to a realistic description of all existing hadron total cross-section data.Comment: 6 pages, 3 figure

The Process gamma* + p -> eta_c + X: A Test for the Perturbative QCD Odderon

The rates of inclusive photo- and electroproduction of the eta_c meson: gamma* + p -> eta_c + X are calculated in the triple Regge region, integrated over the diffractive mass X. For the Regge exchanges we use the hard Pomeron and Odderon, both being calculated in the framework of perturbative QCD. The integrated cross-section depends upon the coupling of the BFKL pomeron to two $C=-1$ odderons, and it is found to be of the order 60 pb for photoproduction and 1.5 pb at Q^2=25 GeV^2.Comment: 19 pages, latex, 7 eps figure

A simple recipe to detect possible C-Odd effects in high energy pˉp\bar p p and pppp

We provide a theorem to suggest that $t=0$ data may already be sufficient to detect possible asymptotic C-odd (Odderon) contributions. This can be done by comparing $\bar p p$ and $pp$ $t=0$ observables such as total cross sections, forward angular distributions and ratios of real to imaginary forward amplitudes for which well defined model independent correlations {must} exist which could already show up at RHIC energy but definitely at LHC energies.Comment: 10 pages in TeX, no figur

A comparative study on two characteristic parametrizations for high energy pp and \=pp total cross sections

Available high energy data for both pp and \=pp total cross sections ($ 5 \ GeV \ < \ \sqrt s \ < \ 1.8 \ TeV$) are described by means of two well-known distinct parametrizations, characteristic of theoretical (``Regge-like" expression) and experimental (``Froissart-Martin-like" expression) practices, respectively. Both are compared from the statistical point of view. For the whole set of present data, statistical analysis ($\chi^2/d.o.f.$) seems to favour a ``Froissart-like" ((ln$s$)$^{\gamma \approx 2}$) rise of the total cross section rather than a ``Regge-like" ($s^{\epsilon}$) one

Universality of low-energy scattering in (2+1) dimensions

We prove that, in (2+1) dimensions, the S-wave phase shift, $\delta_0(k)$, k being the c.m. momentum, vanishes as either $\delta_0 \to {c\over \ln (k/m)} or \delta_0 \to O(k^2)$ as $k\to 0$. The constant $c$ is universal and $c=\pi/2$. This result is established first in the framework of the Schr\"odinger equation for a large class of potentials, second for a massive field theory from proved analyticity and unitarity, and, finally, we look at perturbation theory in $\phi_3^4$ and study its relation to our non-perturbative result. The remarkable fact here is that in n-th order the perturbative amplitude diverges like $(\ln k)^n$ as $k\to 0$, while the full amplitude vanishes as $(\ln k)^{-1}$. We show how these two facts can be reconciled.Comment: 23 pages, Late

Chiral Symmetry and Diffractive Neutral Pion Photo- and Electroproduction

We show that diffractive production of a single neutral pion in photon-induced reactions at high energy is dynamically suppressed due to the approximate chiral symmetry of QCD. These reactions have been proposed as a test of the odderon exchange mechanism. We show that the odderon contribution to the amplitude for such reactions vanishes exactly in the chiral limit. This result is obtained in a nonperturbative framework and by using PCAC relations between the amplitudes for neutral pion and axial vector current production.Comment: 22 pages, 7 figure