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U. Maor

Publications and source records attributed to U. Maor.

At least 19 recordsLinked to original sources
arXiv2016

CGC/saturation approach for high energy soft interactions: `soft' Pomeron structure and $v_{n}$ in hadron and nucleus collisions from Bose-Einstein correlation

In the framework of our model of soft interactions at high energy based on CGC/saturation approach,we show that Bose-Einstein correlations of identical gluons lead to large values of $v_n$. We demonstrate how three dimensional scales of high energy interactions: hadron radius, typical size of the wave function in diffractive production of small masses (size of the constituent quark), and the saturation momentum, influence the values of BE correlations, and in particular, the values of $v_n$. Our calculation shows that the structure of the `dressed' Pomeron leads to values of $v_n$ which are close to experimental values for proton-proton scattering, 20\% smaller than the observed values for proton-lead collisions, and close to lead-lead collisions for 0-10\% centrality. Bearing this result in mind, we conclude that it is premature to consider, that the appearance of long range rapidity azimuthal correlations are due only to the hydrodynamical behaviour of the quark-gluon plasma.

hep-ph↗
arXiv2016

Bose-Einstein correlations and $\mathbf{v_{2n}}$ and $\mathbf{v_{2n-1}}$ in hadron and nucleus collisions

We show that Bose-Einstein correlations of identical particles in hadron and nucleus high energy collisions, lead to long range rapidity correlations in the azimuthal angle. These correlations are inherent features of the CGC/saturation approach, however, their origin is more general than this approach. In framework of the proposed technique both even and odd $v_n$ occur naturally, independent of the type of target and projectile. We are of the opinion that it is premature to conclude that the appearance of azimuthal correlations are due to the hydrodynamical behaviour of the quark-gluon plasma.

hep-ph↗
arXiv2016

CGC/saturation approach for high energy soft interactions: $\mathbf{v_2}$ in proton-proton collisions

In this paper we continue our program to construct a model for high energy soft interactions, based on the CGC/saturation approach. We demonstrate that in our model which describes diffractive physics as well as multi-particle production at high energy, the density variation mechanism leads to the value of $v_2$ which is about $60\% ÷70\%$ of the measured $v_2$. Bearing in mind that in CGC/saturation approach there are two other mechanisms present: Bose enhancement in the wave function and local anisotropy, we believe that the azimuthal long range rapidity correlations in proton-proton collisions stem from the CGC/saturation physics, and not from quark-gluon plasma production.

hep-ph↗
arXiv2015

CGC/saturation approach for soft interactions at high energy: survival probability of the central exclusive production

We estimate the value of the survival probability for central exclusive production, in a model, which is based on the CGC/saturation approach. Hard and soft processes are described in the same framework. At LHC energies, we obtain a small value for the survival probability. The source of the small value, is the impact parameter dependence of the hard amplitude. Our model has successfully described a large body of soft data: elastic, inelastic and diffractive cross sections,inclusive production and rapidity correlations, as well as the $t$-dependence of deep inelastic diffractive production of vector mesons

hep-ph↗
arXiv2015

CGC/saturation approach for soft interactions at high energy: long range rapidity correlations

In this paper we continue our program to build a model for high energy soft interactions, that is based on the CGC/saturation approach.The main result of this paper is that we have discovered a mechanism that leads to large long range rapidity correlations, and results in large values of the correlation function $R\Lb y_1,y_2\Rb \,\geq \,1$, which is independent of $y_1$ and $ y_2$. Such behaviour of the correlation function, provides strong support for the idea, that at high energies the system of partons that is produced, is not only dense, but also has strong attractive forces acting between the partons.

hep-ph↗
arXiv2015

CGC/saturation approach for soft interactions at high energy: inclusive production

In this letter we demonstrate that our dipole model is successful in describing the inclusive production within the same framework as diffractive physics. We believe that this achievement stems from the fact that our approach incorporates the positive features of the Reggeon approach and CGC/saturation effective theory, for high energy QC

hep-ph↗
arXiv2015

CGC/saturation approach for soft interactions at high energy: a two channel model

In this paper we continue the development of a model for strong interactions at high energy, based on two ingredients: CGC/saturation approach and the BFKL Pomeron. In our approach, the unknown mechanism of confinement of quarks and gluons, is characterized by several numerical parameters, which are extracted from the experimental data. We demonstrate that the two channel model, successfully describes the experimental data, including both the value of the elastic slope and the energy behavior of the single diffraction cross section. We show that the disagreement with experimental data of our previous single channel eikonal model [6] stems from the simplified approach used for the hadron structure, and is not related to our principal theoretical input, based on the CGC/saturation approach.

hep-ph↗
arXiv2014

A model for strong interactions at high energy based on the CGC/saturation approach

We present our first attempt to develop a model for soft interactions at high energy, based on the BFKL Pomeron and the CGC/saturation approach. We construct an eikonal-type model, whose opacity is determined by the exchange of the dressed BFKL Pomeron. The Green's function of the Pomeron is calculated in the framework of the CGC/saturation approach. Using five parameters we achieve a good description of the experimental data at high energies ( $W\,\geq\,0.546\,TeV$). The model results in different behaviour for the single and double diffraction cross sections at high energies. The single diffraction cross section reaches a saturated value (about 10 mb) at high energies, while the double diffraction cross section continues growing slowly

hep-ph↗
arXiv2014

A comprehensive model of soft interactions in the LHC era

In this review we present our model which is an example of the self consistent approach that incorporates our theoretical understanding of long distance physics, based both on N=4 SYM for strong coupling and on the matching with the perturbative QCD approach. We demonstrate how important and decisive the LHC data were on strong interactions which led us to a set of the phenomenological parameters that fully confirmed our theoretical expectations, and produced a new picture of the strong interaction at high energy. We also show how far we have come towards creating a framework for the description of minimal bias events for high energy scattering without generating Monte Carlo codes.

hep-ph↗
arXiv2013

Proton-air collisions in a model of soft interactions at high energies

We show that Pomeron interactions generate important corrections to the Gribov-Glauber formula, which is used to extract proton-proton cross sections from proton-air collisions at high energy. We show that these corrections are larger than the errors for proton-air cross sections measured at ultra high energies in cosmic ray experiments. We present a description of these data in our model for soft interactions at high energies, which describes all available accelerator data including that from the LHC.

hep-ph↗
arXiv2013

Long range rapidity correlations in soft interaction at high energies

In this paper we take the next step (following the successful description of inclusive hadron production) in describing the structure of the bias events without the aid of Monte Carlo codes. Two new results are presented :(i) a method for calculating the two particle correlation functions in the BFKLPomeron calculus in zero transverse dimension;and (ii) an estimation of the values of these correlations in a model of soft interactions. Comparison with the multiplicity data at the LHC is given.

hep-ph↗
arXiv2013

Diffraction Production in a Soft Interaction Model: Mass Distributions

In the framework of our model (GLM) for soft interaction with $α'_{\pom}(0)=0$, we propose a procedure based on Gribov's partonic interpretation of the Pomeron, which enables one to calculate the diffractive mass distributions in hadron-hadron scattering. Using the analogy with deep-inelastic scattering, we associate the Pomeron-quark interaction with the Good-Walker sector of the hadron-hadron scattering, and the Pomeron-gluon sector with the t-channel Pomeron interactions. We present predicted mass distributions for the LHC energies

hep-ph↗
arXiv2012

Description of LHC data in a soft interaction model

We show in this paper that we have found a set of parameters in our model for the soft interactions at high energy, that successfully describes all high energy experimental data, including the LHC data. This model is based on a single Pomeron with large intercept $Δ_\pom = 0.23$ and slope $α'_\pom = 0$, that describes both long and short distance processes. It also provides a natural matching with perturbative QCD. All features of our model are similar to the expectations of N=4 SYM, which at present is the only theory that is able to treat srong interactions on a theoretical basis.

hep-ph↗
arXiv2012

Soft interaction model and the LHC data

Most models for soft interactions which were proposed prior to the measurements at the LHC, are only marginally compatible with LHC data, our GLM model has the same deficiency. In this paper we investigate possible causes of the problem, by considering separate fits to the high energy ($W > 500\, GeV$), and low energy ($W < 500\, GeV$) data. Our new results are moderately higher than our previous predictions. Our results for total and elastic cross sections are systematically lower that the recent Totem and Alice published values, while our results for the inelastic and forward slope agree with the data. If with additional experimental data, the errors are reduced, while the central cross section values remain unchanged, we will need to reconsider the physics on which our model is built.

hep-ph↗
arXiv2011

Survival probability of large rapidity gaps in QCD and N=4 SYM motivated model

In this paper we present a self consistent theoretical approach for the calculation of the Survival Probability for central dijet production . These calculations are performed in a model of high energy soft interactions based on two ingredients:(i) the results of N=4 SYM, which at the moment is the only theory that is able to deal with a large coupling constant; and (ii) the required matching with high energy QCD. Assuming, in accordance with these prerequisites, that soft Pomeron intercept is rather large and the slope of the Pomeron trajectory is equal to zero, we derive analytical formulae that sum both enhanced and semi-enhanced diagrams for elastic and diffractive amplitudes. Using parameters obtained from a fit to the available experimental data, we calculate the Survival Probability for central dijet production at energies accessible at the LHC. The results presented here which include the contribution of semi-enhanced and net diagrams, are considerably larger than our previous estimates.

hep-ph↗
arXiv2010

N=4 SYM and QCD motivated approach to soft interactions at high energies

In this paper we construct a model that satisfies the theoretical requisites of high energy soft interactions, based on two ingredients:(i) the results of N=4 SYM, which at present is a unique theory that allows one to deal with a large coupling constant; and (ii) the requirement of matching with high energy QCD. In accordance with these ideas, we assume that the soft Pomeron intercept is rather large, and the slope of the Pomeron trajectory is equal to zero. We derive analytical formulae that sum both enhanced and semi-enhanced diagrams for elastic and diffractive amplitudes. We fit the available experimental data, and predict the valuefor cross sections at the energies accessible at the LHC. The main corrections to the model are studied and evaluated.

hep-ph↗
arXiv2010

QCD motivated approach to soft interactions at high energy: inclusive production

We extend our two component Pomeron model (GLMM) for soft high energy scattering to single inclusive cross sections. We present a suitable formulation which also includes the semi enhanced Pomeron-particle vertex corrections. The available data on single inclusive density $(1/σ_{in})dσ/dy$ in the c.m. energy range of 200-1800 GeV, including the just published Alice Collaboration point at 900 GeV,and the CMS collaboration measurements at 900 and 2360 GeV are well reproduced by our model. We also present predictions covering the complete LHC energy range which can be readily tested in the early low luminosity LHC runs. The results presented in this communication provide additional support to our Pomeron model approach.

hep-ph↗