arXiv subjects

A. I. Lengyel

Publications and source records attributed to A. I. Lengyel.

8 recordsLinked to original sources

arXiv2018

Energy Dependent Prompt Neutron Multiplicity Parameterization for Actinide Photofission

The prompt neutron averaged number and the dependence of prompt neutron yield on fragment mass ν(A) of photofission of actinide nuclei 235U and 238U in the giant dipole resonance energy range has been parameterized. This allows us to describe the observed changes of saw-tooth behavior of neutron yield from the light and heavy fragments using few energy and nucleon composition dependent free parameters and to predict ν(A) for other actinide isotopes.

nucl-th↗

arXiv2016

Averaged number of prompt neutrons calculus for photo-fission of actinides

The empirical calculations of the prompt neutrons average number for photofission of the 232Th, 233U, 234U, 235U, 236U, 238U, 237Np, 239Pu and 241Am actinides has been done as a function of photon energy, mass and charge of the nuclei, which can be used to evaluate the average number for photo-fission of nuclides for which no or scarce data are available.

nucl-ex↗

arXiv2012

Indirect evidence of the Odderon from the LHC data on elastic proton-proton scattering

A simple multipole Pomeron and Odderon model for elastic hadron scattering, reproducing the structure of the first and second diffraction cones is used to analyze $pp$ and $\bar{p}p$ scattering. The main emphasis is on the delicate and non-trivial dynamics in the dip-bump region, at $|t| \approx 1$ GeV$^2$ and at the second cone. The simplicity of the model and the expected smallness of the absorption corrections enables one the control of various contributions to the scattering amplitude, in particular the interplay between the C-even and C-odd components of the amplitude, as well as their relative contribution, changing with $s$ and $t$. The role of the non-linearity of the Regge trajectories is verified. A detailed analysis of the LHC energy region, where most of the exiting models may be either confirmed or ruled out, is presented.

hep-ph↗

arXiv2005

Investigating the role of average color dipole size in BFKL Pomeron phenomenology

Based on the QCD dipole picture of the BFKL Pomeron, we investigate the role played by the saturation scale, Q_{sat}, in obtaining physical values for the affective strong coupling in phenomenological fits to small-x HERA data. The dependence on this scale appears since the collection of color dipoles characterizing the proton target have average size 1/Q_{sat}, which is energy dependent. Physically, this means most of the color dipoles are above but sufficiently close to the border between a saturated and the dilute system. The analysis is first performed in the leading-logs BFKL approach in the saddle-point approximation and it could shed light in further investigations using resummed NLO BFKL kernels

hep-ph↗

arXiv2003

A Kinematically Complete Analysis of the CLAS data on the Proton Structure Function $F_2$ in a Regge-Dual model

The recently measured inclusive electron-proton cross section in the nucleon resonance region, performed with the CLAS detector at the Thomas Jefferson Laboratory, has provided new data for the nucleon structure function $F_2$ with previously unavailable precision. In this paper we propose a description of these experimental data based on a Regge-dual model for $F_2$. The basic inputs in the model are nonlinear complex Regge trajectories producing both isobar resonances and a smooth background. The model is tested against the experimental data, and the $Q^2-$ dependence of the moments is calculated. The fitted model for the structure function (inclusive cross section) is a limiting case of the more general scattering amplitude equally applicable to deeply virtual Compton scattering (DVCS). The connection between the two is discussed.

hep-ph↗

arXiv2002

Explicit model realizing parton-hadron duality

An explicit model realizing parton-hadron duality and fitting the data is suggested. Complex nonlinear Regge trajectories are important ingredients of the model. The inclusion of $Δ$ and $N^*$ trajectories should account for all resonances in the direct channel. The exotic trajectory is responsible for the smooth background.

hep-ph↗

arXiv2000

Finite sum of gluon ladders and high energy cross sections

A model for the Pomeron at $t=0$ is suggested. It is based on the idea of a finite sum of ladder diagrams in QCD. Accordingly, the number of $s$-channel gluon rungs and correspondingly the powers of logarithms in the forward scattering amplitude depends on the phase space (energy) available, i.e. as energy increases, progressively new prongs with additional gluon rungs in the $s$-channel open. Explicit expressions for the total cross section involving two and three rungs or, alternatively, three and four prongs (with $\ln^2(s)$ and $\ln^3(s)$ as highest terms, respectively) are fitted to the proton-proton and proton-antiproton total cross section data in the accelerator region. Both QCD calculation and fits to the data indicate fast convergence of the series. In the fit, two terms (a constant and a logarithmically rising one) almost saturate the whole series, the $\ln^2(s)$ term being small and the next one, $\ln^3(s)$, negligible. Theoretical predictions for the photon-photon total cross section are also given.

hep-ph↗

arXiv1997

Nonlinearities and Pomeron Nonfactorizability in Conventional Diffraction

Alternatives for describing the nonlinear behavior of the first diffraction cone in differential $pp$ and $\bar pp$ elastic cross-section are investigated. High quality fits to the data are presented. We show that the presence in the Pomeron amplitude of two terms with different $t$ dependences is strongly suggested by the data, hinting at a non-factorizable Pomeron even in the field of purely hadronic reactions. The available data, however, do no allow to choose among a nonlinearity in the residues or in the Pomeron trajectory or in both. In all cases, we find an effective slope of the trajectory larger than the one currently used. A nonlinear trajectory with the fitted parameters is used for predicting the mass and the width of the 2$^{++}$ glueball. An excellent agreement is found with the X(1900) candidate from the WA91 experiment.

hep-ph↗