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A. Ster

Publications and source records attributed to A. Ster.

At least 19 recordsLinked to original sources
arXiv2024

Model-independent Odderon results based on new TOTEM data on elastic pp collisions at 8 TeV

Evaluating the H(x, s; pp) scaling function of elastic proton-proton (pp) collisions from recent TOTEM data at sqrt(s) = 8 TeV and comparing it with the same function of elastic proton-antiproton (pp-) data of the D0 collaboration at sqrt(s) = 1.96 TeV, we find, from this comparison alone, an at least 3.79 sigma {\signal} of Odderon exchange. If we combine this model independently obtained result with that of a similar analysis but using TOTEM elastic pp scattering data at sqrt(s) = 7 TeV, which resulted in an at least 6.26 {\sigma} signal, the combined significance of Odderon exchange increases to at least 7.08 {\sigma}, model independently. Further combinations of various datasets in the TeV energy range are detailed in the manuscript

hep-ph↗
arXiv2023

Model-independent Odderon results based on TOTEM data on elastic proton-proton scattering at 8 TeV

We complete the model-independent analysis of the scaling properties of the differential cross section of elastic proton-proton cross sections, including new TOTEM data published in 2022 at $\sqrt{s} = 8$ TeV. We separate the signal and the background region with a new gating method. In the signal region, we find that the statistical significance of Odderon exchange from the combined 7.0 and 8.0 TeV $pp$ data of TOTEM and the 1.96 TeV $p\bar{p}$ data of D0 is at least 7.32$σ$. In the background region, the scaling functions of elastic proton-proton data at 7 and 8 TeV and that of elastic proton-antiproton scattering data at 1.96 TeV agree with a statistical significance not larger than 1.93$σ$.

hep-ex↗
arXiv2021

Evidence of Odderon-exchange from scaling properties of elastic scattering at TeV energies

We study the scaling properties of the differential cross section of elastic proton-proton ($pp$) and proton-antiproton ($p\bar p$) collisions at high energies. We introduce a new scaling function, that scales -- within the experimental errors -- all the ISR data on elastic $pp$ scattering from $\sqrt{s} = 23.5$ to $62.5$ GeV to the same universal curve. We explore the scaling properties of the differential cross-sections of the elastic $pp$ and $p\bar p$ collisions in a limited TeV energy range. Rescaling the TOTEM $pp$ data from $\sqrt{s} = 7$ TeV to $2.76$ and $1.96$ TeV, and comparing it to D0 $p\bar p$ data at $1.96$ TeV, our results provide an evidence for a $t$-channel Odderon exchange at TeV energies, with a significance of at least 6.26$σ$. We complete this work with a model-dependent evaluation of the domain of validity of the new scaling and its violations. We find that the $H(x)$ scaling is valid, model dependently, within $200$ GeV $ \leq \sqrt{s} \leq$ $ 8$ TeV, with a $-t$ range gradually narrowing with decreasing colliding energies.

hep-ph↗
arXiv2020

Scaling of high-energy elastic scattering and the observation of Odderon

We provide a statistically significant observation of the elusive Odderon exchange, based on novel and model-independent analysis of the scaling properties of the differential cross sections of elastic $pp$ and $p\bar p$ scattering in the TeV energy range. We report the statistical significance of the observed Odderon signal at the level of 6.26$σ$.

hep-ph↗
arXiv2020

Proton Holography -- Discovering Odderon from Scaling Properties of Elastic Scattering

We investigate the scaling properties of elastic scattering data at ISR and LHC energies and find that the significance of an Odderon observation is larger than the discovery threshold of 5$σ$. As an unexpected by-product of these investigations, for certain experimentally relevant cases, we also conjecture the possibility of proton holography with the help of elastic proton-proton scattering.

hep-ph↗
arXiv2020

Proton structure and hollowness from Lévy imaging of $pp$ elastic scattering

The recently developed Lévy imaging method enables to extract an important physics information on hadron structure at high energies and ultra-low momentum transfers directly from elastic scattering data. In this work, we employ such a model-independent method to probe the internal structure of the proton and quantify its inelasticity profile in the impact parameter space emerging in proton-proton collisions at the highest available energy of $\sqrt{s} = 13$ TeV. The inelasticity profile function and its error band for the proton and its substructure have been reconstructed at different energies and the proton hollowness (or "black-ring") effect with beyond 5$σ$ significance has been found at 13 TeV.

hep-ph↗
arXiv2020

Odderon and proton substructure from a model-independent Levy imaging of elastic $pp$ and $p\bar p$ collisions

We describe a new and model-independent Lévy imaging method of quality fits to the published datasets and reconstruct the amplitude of high-energy $pp$ and $p\bar p$ elastic scattering processes. This method allows us to determine the excitation function of the shadow profile $P(b)$, the elastic slope $B(t)$ and the nuclear phase $ϕ(t)$ functions of $pp$ and $p\bar p$ collisions directly from the data. Surprisingly, notable qualitative differences in $B(t)$ for $pp$ and for $p\bar p$ collisions point towards an Odderon effect. As a by-product, we clearly identify the proton substructure with two different sizes at the ISR and LHC energies, that has striking similarity to a dressed quark (at the ISR) and a dressed diquark (at the LHC). We present model-independent results for the corresponding sizes and cross-sections for such a substructure for the existing data at different energies.

hep-ph↗
arXiv2019

Model-independent femtoscopic Levy imaging for elastic proton-proton scattering

A model independent Levy expansion method is introduced to describe nearly Levy shaped squared moduli of Fourier transforms. We apply this method to precisely characterize the most recent elastic scattering data of proton-proton collisions at $\sqrt{s} = 13$ TeV. The results reveal a substructure of protons, which is found to be significantly larger and darker in high energy proton-proton collisions at the TeV scale, as compared to a rather faint and apparently overlooked sub-structure, that we also identify in elastic proton-proton scattering at the ISR energy range of $\sqrt{s} = 23 - 62$ GeV.

hep-ph↗
arXiv2019

Convergence properties of Lévy expansions: implications for Odderon and proton structure

We detail here the convergence properties of a new model-independent imaging method, the Lévy expansion, that seems to play an important role in the analysis of the differential cross section of elastic hadron-hadron scattering. We demonstrate, how our earlier results concerning the Odderon effects in the differential cross-section of elastic proton-proton and proton-antiproton scattering as well as those related to apparent sub-structures inside the protons were obtained in a convergent and stable manner.

hep-ph↗
arXiv2019

Lévy imaging of elastic hadron-hadron scattering: Odderon and inner structure of the proton

A novel model-independent Lévy imaging method is employed for reconstruction of the elastic $pp$ and $p\bar p$ scattering amplitudes at low and high energies. The four-momentum transfer $t$ dependent elastic slope $B(t)$, the nuclear phase $ϕ(t)$ as well as the excitation function of the shadow profile $P(b)$ have been extracted from data at ISR, Tevatron and LHC energies. We found qualitative differences in properties of $B(t)$ and $ϕ(t)$ between $pp$ and for $p\bar p$ collisions, that indicate an Odderon effect. A proton substructure has also been identified and found to have two different sizes, comparable to that of a dressed quark at the ISR and of a dressed diquark at the LHC energies, respectively.

hep-ph↗
arXiv2011

Oscillating HBT radii and the time evolution of the source - sqrt(s_NN) = 200 GeV Au+Au data analyzed with azimuthally sensitive Buda-Lund hydro model

Identified particle spectra of pions, kaons and (anti)protons, and elliptic flow and azimuthal dependence of Bose-Einstein or HBT correlations of identified pions in sqrt(s_NN) = 200 GeV Au+Au collisions is analyzed simultaneously using an ellipsoidally symmetric generalization of the Buda-Lund hydrodynamical model. The transverse flow is found to be faster in the reaction plane than out of plane, which results in a reaction zone that gets slightly more elongated in-plane than out of plane.

nucl-th↗
arXiv2010

Spectra, elliptic flow and azimuthally sensitive HBT radii from Buda-Lund model for sqrt(s(NN)) = 200 GeV Au+Au collisions

We present calculations of elliptic flow and azimuthal dependence of correlation radii in the ellipsoidally symmetric generalization of the Buda-Lund hydrodynamic model of hadron production in high-energy nuclear collisions. We compare them to data from RHIC by simultaneous fits to azimuthally integrated invariant spectra of pions, kaons and protons-antiprotons measured by PHENIX in Au+Au reactions at center of mass energy of 200 AGeV. STAR data were used for azimuthally sensitive two-particle correlation function radii and for the transverse momentum dependence of the elliptic flow parameter v2. We have found that the transverse flow is faster in the reaction plane then out of plane, which results in a reaction zone that gets slightly more elongated in-plane than out of plane. The model parameters extracted from the fits are shown and discussed.

nucl-th↗
arXiv2008

Diffraction at TOTEM

The TOTEM experiment at the LHC measures the total proton-proton cross section with the luminosity-independent method and the elastic proton-proton cross-section over a wide |t|-range. It also performs a comprehensive study of diffraction, spanning from cross-section measurements of individual diffractive processes to the analysis of their event topologies. Hard diffraction will be studied in collaboration with CMS taking advantage of the large common rapidity coverage for charged and neutral particle detection and the large variety of trigger possibilities even at large luminosities. TOTEM will take data under all LHC beam conditions including standard high luminosity runs to maximize its physics reach. This contribution describes the main features of the TOTEM physics programme including measurements to be made in the early LHC runs. In addition, a novel scheme to extend the diffractive proton acceptance for high luminosity runs by installing proton detectors at IP3 is described.

hep-ex↗
arXiv2008

Universal scaling of the elliptic flow data at RHIC

Recent PHOBOS measurements of the excitation function for the pseudo-rapidity dependence of elliptic flow in Au+Au collisions at RHIC, have posed a significant theoretical challenge. Here we show that these differential measurements, as well as the RHIC measurements on transverse momentum satisfy a universal scaling relation predicted by the Buda-Lund model, based on exact solutions of perfect fluid hydrodynamics. We also show that recently found transverse kinetic energy scaling of the elliptic flow is a special case of this universal scaling.

nucl-th↗
arXiv2007

From Quark Gluon Plasma to a Perfect Fluid of Quarks and Beyond

With high energy heavy ion collisions one tries to create a new forms of matter that is similar to the one present at the birth of our Universe. Recent development on flow pattern, initial energy-density and freeze-out temperature shows that most likely this new form of matter is in a deconfined state, has colored degrees of freedom and is more fluid-like than gas-like. In present paper we calculate estimations on the physical properties of this new-old matter.

nucl-th↗
arXiv2006

Universal scaling of the rapidity dependent elliptic flow and the perfect fluid at RHIC

The pseudo-rapidity dependence of the elliptic flow at various excitation energies measured by the PHOBOS Collaboration in Au+Au collisions at RHIC is one of the surprising results that has not been explained before in terms of hydrodynamical models. Here we show that these data are in agreement with theoretical predictions based on perfect fluid hydrodynamics. We also show that these PHOBOS data satisfy the universal scaling relation predicted by the Buda-Lund hydrodynamical model, based on exact solutions of perfect fluid hydrodynamics.

nucl-th↗
arXiv2005

Understanding the rapidity dependence of the elliptic flow and the HBT radii at RHIC

The pseudo-rapidity dependence of the elliptic flow at various excitation energies measured by the PHOBOS Collaboration in Au+Au collisions at RHIC is one of the surprising results that has not been explained before in terms of hydrodynamical models. Here we show that these data are in agreement with theoretical predictions and satisfy the universal scaling relation predicted by the Buda-Lund hydrodynamical model, based on exact solutions of perfect fluid hydrodynamics. We also show a theoretical prediction on the rapidity and transverse momentum scaling of the HBT radii measured in heavy ion collisions, based on the Buda-Lund model.

nucl-th↗