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1.
A reggeon field theory with two vacuum quantum numbers Regge poles, the pomeron and the f-reggeon is presented. In such a theory only one stable fixed point appears which is sensibly different from that governing a RFT with the pomeron alone. This fact is responsible for the modifications of the critical parameters of the pomeron. In particular, the intercept of the bare pomeron increases and approaches the phenomenological value. 相似文献
2.
In the hard pomeron theory with the number of colours the diffractive amplitude obtained in [3] is compared with the results found for in [1] and in the dipole approach in [5]. It is shown that the double pomeron exchange contribution can be substituted by
an equivalent triple pomeron interaction term. After such a substitution the triple pomeron vertices in [1,3,5] essentially
coincide. It is demonstrated that, in any form, the triple pomeron vertex is conformal invariant. It is also shown that higher
order densities in the dipole approach do not involve 1 to k pomeron verteces with but are rather given by a set of pomeron fan diagrams with only a triple pomeron coupling.
Received: 11 December 1997 / Revised version: 6 February 1998 / Published online: 7 August 1998 相似文献
3.
J. Ellis G.G. Ross J. Williams 《The European Physical Journal C - Particles and Fields》1999,10(3):443-460
We suggest that the pseudo-rapidity cut dependence of diffractive deep-inelastic scattering events at HERA may provide a
sensitive test of models of diffraction. A comparison with the experimental cross section shows that the Donnachie-Landshoff
model and a simple two-gluon exchange model of the pomeron model are disfavoured. However a model with a direct coupling of
the pomeron to quarks is viable for a harder quark–pomeron form factor, as is a model based on the leading-twist operator
contribution. We also consider a direct-coupling scalar pomeron model. We comment on the implications of these results for
the determination of the partonic structure of the pomeron.
Received: 5 March 1999 / Published online: 3 August 1999 相似文献
4.
The gluon recombination effect in the pomeron is studied by using the modified Gribov-Levin-Ryskin evolution equation. We find that the measured parton distributions in the pomeron can be generated dynamically from a purely gluonic input on assuming a small size for the pomeron. 相似文献
5.
The violation of the Froissart bound resulting from repeated exchanges of pomerons in a multi-Regge model is avoided by assuming that some pomeron couplings vanish. The couplings can be chosen such that an input pomeron can produce an output pole coinciding with the input pomeron, and a two-pomeron cut. The main aim is to show that the structure of pomeron couplings can play an important role in calculations involving many pomerons 相似文献
6.
M. Braun 《The European Physical Journal C - Particles and Fields》1999,6(2):321-330
The amplitude for 4 interacting reggeized gluons is studied in the high-colour limit. The leading order amplitude is explicitly
shown to reduce to a pair of reggeons, i.e to a single BFKL pomeron. The next-to-leading order diffractive amplitude is found
to split into a double pomeron exchange and triple pomeron contribution. The obtained three-pomeron vertex is different from
the originally proposed in [2].
Received: 26 June 1997 / Revised version: 28 February 1998 / Published online: 3 September 1998 相似文献
7.
The dual properties of the inclusive reaction π?p → pX are studied over a wide energy range by exploiting the scaling behaviour. Semi-local duality is found to be well satisfied. An energy-dependent triple-Regge analysis reveals a strong triple-pomeron coupling. There is some evidence of an abnormal component in which diffractively produced resonances are dual to pomeron exchange. Combining duality with factorization leads to relations between production cross sections of meson and baryon resonances in πp and pp collisions, which are compatible with existing experimental data. 相似文献
8.
M.A. BraunA.N. Tarasov 《Nuclear Physics B》2011,851(3):533-550
It is shown by numerical calculations that the convoluted QCD pomeron propagator in the external field created by a solution of the Balitsky-Kovchegov equation in the nuclear matter vanishes at high rapidities. This may open a possibility to apply the perturbative approach for the calculation of pomeron loops. 相似文献
9.
10.
11.
We demonstrate that in each ghost-free dual model with one minor restriction, there exists a critical dimensionality of space-time in which the pomeron singularity becomes a factorizable Regge pole. In each model when this dimensionality is chosen, the pomeron emerges with twice the intercept and half the slope of the leading secondary (f) trajectory. We explicitly construct the pomeron propagator and the operator coupling the pomeron to the reggeon sector for the general dual model, including the lower-lying negative-G-parity pomeron in the Neveu-Schwarz model. Gauge identities and physical states in the pomeron sector are also investigated. In all of the dual models the pomeron form factors exhibit a generalized f dominance and modified Wu-Yang behavior. 相似文献
12.
J. Miller 《The European Physical Journal C - Particles and Fields》2008,56(1):39-55
In this paper, the contribution of hard processes described by BFKL pomeron exchange is taken into account by calculating
the first enhanced diagram. The survival probability is estimated, using the ratio of the first enhanced diagram and the single
pomeron amplitude, taking into account all essential pomeron loop diagrams in the toy model of Mueller. The triple pomeron
vertex is calculated explicitly in the momentum representation. This calculation is used for estimating the survival probability,
and it turns out that the survival probability is small, at 0.4%. Hard pomeron rescattering processes contribute substantially
to the survival probability. 相似文献
13.
We determine the intermediate mass distribution of the dual resonance pomeron at the one-loop level and we show that the mass distribution obtained is remarkably similar to a suitably defined mass distribution in the dual multiperipheral model. Thus it is suggestive to identify the intermediate states of the dual resonance pomeron with multipheripheral processes. 相似文献
14.
M. A. Braun 《The European Physical Journal C - Particles and Fields》2009,63(2):287-296
The lowest order pomeron loop is calculated for the leading conformal weight with full dependence of the triple-pomeron vertex
on intermediate conformal weights. The loop is found to be convergent. Its contribution to the pomeron Green function begins
to dominate already at rapidities 10–15. The pomeron pole renormalization is found to be quite small due to a rapid fall of
the triple-pomeron vertex with rising conformal weights. 相似文献
15.
A.C. Irving 《Nuclear Physics B》1977,121(1):176-188
A model for predicting diffractive production of meson resonances is presented. From a study of the s and t dependence of the available cross section and density matrix data, we deduce that the assumption of f, f′ dominance of the pomeron is violated. Relative to elastic scattering, where f, f′ dominance works well, the pomeron component in these inelastic processes appears to be about one half as strong in amplitude. 相似文献
16.
We consider a model for elastic scattering and inelastic diffractive production at high energy, which is inspired by Quantum Chromodynamics. The pomeron arises in our model from gluon exchange between quark constituents. The color-neutrality of each hadron implies strong cancellations among the gluon exchanges. Hence our model is “subtractive”, in contrast to the old “additive” quark model. The subtractive model provides a natural explanation for the large cross section which is observed for diffractive dissociation. We show that multiple gluon exchange contributes significantly, alongside two gluon exchange, in building the pomeron. 相似文献
17.
James S. Ball 《Nuclear Physics B》1976,102(2):347-352
By choosing a suitable but unconventional bare pomeron propagator and bare triple-pomeron coupling the Dyson equations of reggeon calculus are shown to reduce to algebraic equations for the various coupling constants. The resulting pomeron, which is identical to the input pomeron is the familiar black or gray disk. 相似文献
18.
19.
Susumu Koretune 《Physics letters. [Part B]》1979,83(2):218-220
The sum rule of the πN total cross section is derived with use of the anticommutator of currents restricted at the nullplane and PCAC. Through this sum rule, the quantitative relation between the sea quark distribution and the pomeron is given. 相似文献
20.
M. A. Braun A. N. Tarasov 《The European Physical Journal C - Particles and Fields》2008,58(3):383-394
The contribution of the simplest loops is studied in the local reggeon field theory with a supercritical pomeron in nuclear
matter. It is shown that the latter transforms the supercritical pomeron into a subcritical one. Renormalization of the intercept
and difficulties related to the fact that the renormalised intercept is complex are discussed. Numerical results with the
conventional parameters are reported. 相似文献