arXiv subjects

István Szanyi

Publications and source records attributed to István Szanyi.

15 recordsLinked to original sources

arXiv2025

Odderon Exchange in Elastic Proton-Proton and Proton-Antiproton Scattering at TeV Energies

The odderon, a leading crossing-odd $t$-channel exchange, was first proposed by L. Lukaszuk and B. Nicolescu in 1973, but its existence remained elusive for 48 years. Elastic proton-proton scattering measurements at CERN's Large Hadron Collider (LHC) and elastic proton-antiproton scattering measurements at FNAL's Tevatron, performed at TeV-scale center-of-mass energies ($\sqrt{s}$) and over wide ranges of squared four-momentum transfer ($t$), opened new opportunities to study the physics of elastic hadronic processes which ultimately led to the discovery of odderon exchange in the nonperturbative domain of strong interactions, as detailed in this dissertation. In quantum chromodynamics (QCD), the fundamental theory of strong interactions, the odderon is described in the perturbative regime as a $t$-channel exchange of an odd number of interacting gluons.

hep-ph↗

arXiv2024

Dip-Bump Structure in Proton's Single Diffractive Dissociation at the Large Hadron Collider

By extending the dipole Pomeron (DP) model, successful in describing elastic nucleon-nucleon scattering, to proton single diffractive dissociation (SD), we predict a dip-bump structure in the squared four-momentum transfer ($t$) distribution of proton's SD. Structures in the $t$ distribution of single diffractive dissociation are predicted around $t=-4$ GeV$^2$ at LHC energies in the range of 3 GeV$^2$ $\lesssim|t|\lesssim$ 7 GeV$^2$. Apart from the dependence on $s$ (total energy squared) and $t$ (squared momentum transfer), we predict also a dependence on missing masses. We include the minimum set of Regge trajectories, namely the Pomeron and the Odderon, indispensable at the LHC. Further generalization, e.g., by the inclusion of non-leading Regge trajectories, is straightforward. The present model contains two types of Regge trajectories: those connected with $t$-channel exchanges (the Pomeron, the Odderon, and non-leading (secondary) reggeons) appearing at small and moderate $-t$, where they are real and nearly linear, as well as direct-channel trajectories $α(M^2)$ related to missing masses. In this paper, we concentrate on structures in $t$ neglecting (for the time being) resonances in $M^2$.

hep-ph↗

arXiv2023

Regge models of proton diffractive dissociation based on factorization and structure functions

Recent results by the authors on proton diffractive dissociation (single, double and central) in the low-mass resonance region with emphasis on the LHC kinematics are reviewed and updated. Based on the previous ideas that the contribution of the inelastic proton-Pomeron vertex can be described by the proton structure function, the contribution of the inelastic Pomeron-Pomeron vertex appearing in central diffraction is now described by a Pomeron structure function.

hep-ph↗

arXiv2023

Nonlinear Regge trajectories and saturation of the Hagedorn spectrum

We argue that two seemingly different phenomena, namely the well-known saturation of the Hagedorn exponential distribution and the less familiar saturation of Regge trajectories at resonance masses $m\approx$ 2-2.5 GeV are related and have the same origin: quark deconfinement. We show that the slope of the real part of non-linear Regge trajectories determines the prefactor $f(m)$ in Hagedorn's resonance mass density distribution $ρ(m)$. While the Hagedorn distribution comes from statistics, Regge trajectories contain dynamics.

hep-ph↗

arXiv2020

Pomeron/glueball and odderon/oddball trajectories

We predict glueball/oddball resonances lying on the pomeron/odderon trajectories. A simple new form of the trajectories, with threshold and asymptotic behaviour required by analyticity and unitarity, is proposed. The parameters of these (pomeron and odderon) trajectories are fitted to the data on high-energy elastic proton-proton scattering. The fitted trajectories are extrapolated to the resonance region to predict masses and widths of glueballs and oddballs. The (pomeron and odderon) trajectories may be used to calculate processes of central exclusive diffraction (CED).

hep-ph↗

arXiv2019

Pomeron-pomeron scattering

Central exclusive diffractive (CED) production of meson resonances potentially is a factory producing new particles, in particular a glueball. The produced resonances lie in trajectories with vacuum quantum numbers, essentially on the pomeron trajectory. A tower of resonance recurrences, the production cross section and the resonances widths are predicted. A new feature is the form of the non-linear pomeron trajectory, producing resonances (glueballs) with increasing widths. At LHC energies, in the nearly forward direction the $t$-channel both in elastic, single or double diffraction dissociation as well as in CED is dominated by pomeron exchange (the role of secondary trajectories is negligible, however a small contribution from the odderon may be present).

hep-ph↗

arXiv2019

New physics from TOTEM's recent measurements of elastic and total cross sections

We analyze the recently discovered phenomena in elastic proton-proton scattering at the LHC, challenging the standard Regge-pole theory: the low-$|t|$ "break" (departure from the exponential behavior of the diffraction cone), the accelerating rise with energy of the forward slope $B(s,t=0)$, the absence of secondary dips and bumps on the cone and the role of the odderon in the forward phase of the amplitude, $ρ(13~TeV)=0.1\pm0.01$, and especially its contribution at the dip region, measured recently by TOTEM. Relative contributions from different components to the scattering amplitude are evaluated from the fitted model.

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arXiv2019

Elastic and diffractive scattering in the LHC era

We review elastic and diffractive scattering of protons (called also "forward physics") with emphasis on the LHC data, especially those deviating from the expectations based on extrapolations from earlier measurements at the ISR, Fermilab and thus triggering searches for new ideas, models and theories. We list these new data and provide a brief introduction of available theoretical approaches, mainly those based on analyticity, crossing symmetry and unitarity, particularly the Regge-pole model realizing these concepts. Fits to the data are presented and tensions between theoretical predictions and the data that may indicate the way to further progress are in the focus of our paper.

hep-ph↗

arXiv2018

Hollowness in $pp$ and $p \bar p$ scattering in a Regge model

The proton-proton and proton-antiproton inelasticity profiles in the impact parameter display very interesting and sensitive features which cannot be deduced solely from the current large body of high-energy scattering data. In particular, phenomenological studies exhibit a link between the ratio of the real to imaginary parts of the elastic scattering amplitude at a finite momentum transfer, and the corresponding change of character of the inelastic processes from central to peripheral collisions. We describe how a theoretical model, accommodating the existing data, based on the Regge hypothesis including both the Pomeron and odderon as double poles, and $ω$ and $f$ mesons as single poles in the complex-$J$ plane, generates a hollow in the inelasticity at low impact parameters. The hollowness effect, which generally may be sensitive to model details, does unequivocally take place both for $pp$ and $p \bar p$ collisions within the applied Regge framework, indicating inapplicability of inelasticity-folding geometric approaches.

hep-ph↗

arXiv2018

Shape of Proton and the Pion Cloud

Proton-proton differential and total cross sections provide information on the energy dependence of proton shape and size. We show that the deviation from exponential behavior of the diffraction cone observed near $t=-0.1$ GeV$^2$, (so-called break), both at the ISR and the LHC follows from the $t$-channel two-pion loop contributions, imposed by unitarity. By using a simple Regge-pole model, we extrapolate the "break" from the ISR energy region to that of the LHC. This allows us to answer two important questions: 1) To what extent is the "break" observed recently at the LHC a "recurrence" of that seen at the ISR (universality)? 2) What is the relative weight of two-pion effect to the vertex coupling (Regge residue) compared to expanding size (pomeron propagator) in producing the "break"? We find that the effect comes both from the Regge residue (proton-pomeron coupling) and from the Regge propagator. A detail analyses of their balance, including the correlation between the relevant parameters is presented.

hep-ph↗

arXiv2017

Approaching the asymptotics at the LHC

Recent results on the slope of the $pp$ diffraction cone measured by TOTEM at $7$ and $8$ GeV show an unexpected rapid rise in $s$, close to $B(s)\sim \ln^2$, rather than $\ln s$, typical of the Regge-pole predictions. We show that the new phenomenon can be accommodated by the inclusion of unitarity corrections to a simple Regge (pomeron) pole exchange. Interestingly, the odderon may also promote the acceleration of $B(s)$. The onset of the new regime may be indicative of the approach to the asymptotic dynamics of strong interactions. We analyse the new data together with other available forward measurable in a unitarized Regge dipole. Unitarization proves crucial in fitting the data, especially those on the slope $B(s)$ showing a change from the $\ln (s)$ to $\ln^2 (s)$ behavior. Having fitted the free parameters of the unitarized model to the data, we predict the behavior of the cross sections and the slope at still higher energies, including those asymptotic.

hep-ph↗

arXiv2017

Structures in the high-energy proton-proton diffraction cone

The otherwise exponential high-energy proton-proton diffraction cone has two prominent structures, which are namely the "break" staying fixed around $t \approx -0.1$ GeV$^2$ and the "dip" moving with increasing energy logarithmically towards smaller $|t|$ values. While at the ISR the two structures are separated by a distance of about $1$ GeV$^2$, at the LHC the dip comes close to the periphery of the "break", thus affecting its parametrization. The Regge theory gives some opportunity to describe these phenomena which have still disputable and quite different physics.

hep-ph↗

arXiv2017

Duality relations in proton diffraction dissociation and in DIS

We use duality to relate resonances in missing mass $M$ to the large-mass diffraction dissociation of protons. In deep inelastic lepton-hadron scattering (DIS), hadronic resonances are related by duality in $Q^2$ to the low-$x$, smooth behaviour of the DIS structure functions.

hep-ph↗

arXiv2017

Fine structure of the diffraction cone: manifestation of t channel unitarity

We show that the deviation from exponential behavior of the diffraction cone observed near t=-0.1 GeV^2 both at ISR and the LHC (so-called break) follows from a two-pion loop in the t channel, imposed by unitarity. By using a simple Regge-pole model, we extrapolate the "break" from the ISR energy region to that of the LHC.

hep-ph↗

arXiv2017

Structures in the diffraction cone: the "break" and "dip" in high-energy proton-proton scattering

Anticipating forthcoming publication by the TOTEM collaboration of low-t elastic scattering data at \sqrt{s}=13 and 2.76 TeV, hereby we emphasize the correlation between two prominent structures seen upon the otherwise exponential diffraction cone, namely a "break" staying fixed around t=-0.1 GeV^2 and a dip moving with energy logarithmically inwards; while at the ISR the two structures are separated by a distance of about 1~GeV^2, at the LHC the dip comes close to the periphery of the "break", thus affecting its parametrization. An unbiased disentangling and identification of the break at the LHC should account for this correlation.

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