scholarly journals Asymptotic regimes for hadron diffractive scatterings and Coulomb interaction: Arguments for the black disk mode

2016 ◽  
Vol 31 (11) ◽  
pp. 1650053
Author(s):  
V. V. Anisovich ◽  
V. A. Nikonov ◽  
J. Nyiri
Keyword(s):  
Function Technique ◽  
Coulomb Interactions ◽  
Black Disk ◽  
Asymptotic Regime ◽  
8 Tev ◽  
Impact Parameter Space ◽  
The Impact ◽  
Disk Mode ◽  
Broad Energy ◽  
Hadronic Amplitude

Comparative analysis of the interplay of hadron and Coulomb interactions in [Formula: see text] scattering amplitudes is performed in a broad energy interval, [Formula: see text], for two extreme cases: for the asymptotic interactions of hadrons in black disk and resonant disk modes. The interactions are discussed in terms of the [Formula: see text]-matrix function technique. In the asymptotic regime, the real part of the hadronic amplitude is concentrated in both cases on the boundary of the disks in the impact parameter space but the LHC energy region is not asymptotic for the resonant disk mode that lead to a specific interplay of hadronic and Coulombic amplitudes. For the [Formula: see text] scattering at [Formula: see text] an interplay of the hadron and Coulomb interactions in the resonant disk modes is realized in a shoulder in [Formula: see text] at [Formula: see text]. The absence of such a shoulder in the data at 8 TeV can be considered as an argument against the resonant disk mode.

scholarly journals Hadron diffractive scattering at ultrahigh energies and Coulomb interaction

2016 ◽  
Vol 31 (08) ◽  
pp. 1650051 ◽  
Author(s):  
V. V. Anisovich ◽  
V. A. Nikonov
Keyword(s):  
Function Technique ◽  
Interference Effects ◽  
Coulomb Interactions ◽  
Black Disk ◽  
The Real ◽  
Diffractive Scattering ◽  
Impact Parameter Space ◽  
K Matrix ◽  
The Impact

We study the interplay of hadronic and Coulomb interactions for pp scattering at LHC energies on the basis of the previous determination of the real part of the amplitude [V. V. Anisovich, V. A. Nikonov and J. Nyiri, Int. J. Mod. Phys. A 30, 1550188 (2015)]. The interference of hadron and Coulomb interactions is discussed in terms of the K-matrix function technique. Supposing the black disk mode for the asymptotic interaction of hadrons, we calculate interference effects for the energies right up to [Formula: see text] TeV. It turns out that the real part of the amplitude is concentrated in the impact parameter space at the border of the black disk that results in a growth of interplay effects with the energy increase.

Real part of scattering amplitude at ultrahigh energies

2015 ◽  
Vol 30 (30) ◽  
pp. 1550188 ◽  
Author(s):  
V. V. Anisovich ◽  
V. A. Nikonov ◽  
J. Nyiri
Keyword(s):  
Impact Parameter ◽  
Parameter Space ◽  
Scattering Amplitude ◽  
Black Disk ◽  
Asymptotic Regime ◽  
The Real ◽  
Impact Parameter Space ◽  
The Impact

On the basis of requirements of unitarity and analyticity we analyze the real and imaginary parts of the scattering amplitude at recent ultrahigh energies, [Formula: see text]. The predictions for the region [Formula: see text] and [Formula: see text] are given supposing the black disk asymptotic regime. It turns out that the real part of the amplitude is concentrated in the impact parameter space at the border of the black disk.

scholarly journals TACHYON DYNAMICS OF THE BLACK DISC LIMIT IN THE HARD SMALL x PROCESSES IN QCD

2006 ◽  
Vol 21 (07) ◽  
pp. 549-558 ◽  
Author(s):  
B. BLOK ◽  
L. FRANKFURT
Keyword(s):  
Cross Section ◽  
Impact Parameter ◽  
High Energy ◽  
Black Disk ◽  
Black Disc ◽  
Energy Behavior ◽  
Small X ◽  
The Cross ◽  
The Impact ◽  
Black Disc Limit

We investigate the effective field theory (EFT) which gives the approximate description of the scattering of two hard small dipoles in the small x processes in QCD near the black disc limit (BDL). We argue that the perturbative QCD approaches predict the existence of tachyon and visualize it in the approximation where α′P=0. We demonstrate that the high energy behavior of the cross-section depends strongly on the diffusion law in the impact parameter plane. On the other hand, almost threshold behavior of the cross section of the hard processes and multiplicities, i.e. fast increase of cross sections (color inflation), melting of ladders into color network and softening of the longitudinal distributions of hadrons are qualitatively insensitive to the value of diffusion in the impact parameter space. We evaluate α′P near the black disk limit and find significant α′P as the consequence of the probability conservation.

scholarly journals Asteroseismology of low-mass stars: the balance between partial ionization and Coulomb interactions

2021 ◽  
Vol 507 (4) ◽  
pp. 5747-5757
Author(s):  
Ana Brito ◽  
Ilídio Lopes
Keyword(s):  
Electrostatic Interactions ◽  
Chemical Elements ◽  
Acoustic Oscillation ◽  
Coulomb Interactions ◽  
Low Mass Stars ◽  
Stellar Oscillations ◽  
Diagnostic Potential ◽  
Low Mass ◽  
Coulomb Effects ◽  
The Impact

ABSTRACT All cool stars with outer convective zones have the potential to exhibit stochastically excited stellar oscillations. In this work, we explore the outer layers of stars less massive than the Sun. In particular, we have computed a set of stellar models ranging from 0.4 to 0.9 M⊙ with the aim at determining the impact on stellar oscillations of two physical processes occurring in the envelopes of these stars. Namely, the partial ionization of chemical elements and the electrostatic interactions between particles in the outer layers. We find that alongside with partial ionization, Coulomb effects also impact the acoustic oscillation spectrum. We confirm the well-known result that as the mass of a star decreases, the electrostatic interactions between particles become relevant. We found that their impact on stellar oscillations increases with decreasing mass, and for the stars with the lowest masses (M ≲ 0.6 M⊙), it is shown that Coulomb effects dominate over partial ionization processes producing a strong scatter on the acoustic modes. The influence of Coulomb interactions on the sound-speed gradient profile produces a strong oscillatory behaviour with diagnostic potential for the future.

scholarly journals High Energy Rho Meson Leptoproduction §

2014 ◽  
Vol 1 (1) ◽  
pp. 33-35
Author(s):  
Adrien Besse ◽  
Lech Szymanowski ◽  
Samuel Wallon
Keyword(s):  
Cross Sections ◽  
Scattering Amplitude ◽  
Good Description ◽  
High Energy ◽  
Energy Limit ◽  
Rho Meson ◽  
Forward Limit ◽  
Helicity Amplitudes ◽  
Impact Parameter Space ◽  
The Impact

We investigate the longitudinal and transverse polarized cross-sections of the leptoproduction of the ρ meson in the high energy limit. Our model is based on the computation of the impact factor γ*(λγ)→ ρ (λρ) using the twist expansion in the forward limit which is expressed in the impact parameter space. This treatment involves in the final stage the twist 2 and twist 3 distribution amplitudes (DAs) of the ρ meson and the dipole scattering amplitude. Taking models that exist for the DAs and for the dipole cross-section. We get a phenomenological model for the helicity amplitudes. We compare our predictions with HERA data and get a fairly good description for large enough virtualities of the photon. PACS number(s): 13.60.Le, 12.39.St, 12.38.Bx.

scholarly journals Some Recent Results on High-Energy Proton Interactions

Particles ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 57-69 ◽  
Author(s):  
I. M. Dremin
Keyword(s):  
Cross Sections ◽  
Scattering Amplitude ◽  
High Energy ◽  
Unitarity Condition ◽  
Total Cross Sections ◽  
Energy Proton ◽  
Elastic Scattering Amplitude ◽  
Energy Behavior ◽  
Impact Parameter Space ◽  
The Impact

Recent experimental results about the energy behavior of the total cross sections, the share of elastic and inelastic contributions to them, the peculiar shape of the differential cross section and our guesses about the behavior of real and imaginary parts of the elastic scattering amplitude are discussed. The unitarity condition relates elastic and inelastic processes. Therefore it is used in the impact-parameter space to get some information about the shape of the interaction region of colliding protons by exploiting new experimental data. The obtained results are described.

scholarly journals PROTON PROFILE FUNCTION AT 52.8 GeV

2007 ◽  
Vol 16 (09) ◽  
pp. 2923-2926 ◽  
Author(s):  
GEOVANNA LUIZ PEREIRA DA SILVA ◽  
MÁRCIO JOSÉ MENON ◽  
REGINA FONSECA ÁVILA
Keyword(s):  
Error Propagation ◽  
Scattering Amplitude ◽  
Profile Function ◽  
Proton Proton ◽  
Section Data ◽  
Elastic Proton ◽  
Model Independent ◽  
Impact Parameter Space ◽  
The Impact ◽  
Novel Model

We present the results of a novel model-independent fit to elastic proton-proton differential cross section data at [Formula: see text]. Taking into account the error propagation from the fit parameters, we determine the scattering amplitude in the impact parameter space (the proton profile function) and its statistical uncertainty region. We show that both the real and imaginary parts of the profile are consistent with two dynamical contributions, one from a central dense region, up to roughly 1 fm and another from a peripheral evanescent region from 1 to 3 fm.

scholarly journals Intercomparison between Lagrangian and Eulerian simulations of the development of mid-latitude streamers as observed by CRISTA

2004 ◽  
Vol 4 (5) ◽  
pp. 6185-6212
Author(s):  
F. Khosrawi ◽  
J.-U. Grooß ◽  
R. Müller ◽  
P. Konopka ◽  
W. Kouker ◽  
...  
Keyword(s):  
Middle Atmosphere ◽  
Transport Processes ◽  
Lagrangian Model ◽  
Function Technique ◽  
Small Scale ◽  
Mixing Ratios ◽  
Infrared Spectrometer ◽  
The Impact ◽  
Small Scale Structures

Abstract. During the CRISTA-1 mission three pronounced fingerlike structures reaching from the lower latitudes to the mid-latitudes, so-called streamers, were observed in the measurements of several trace gases in early November 1994. A simulation of these streamers in previous studies employing the KASIMA (Karlsruhe Simulation Model of the Middle Atmosphere) and ROSE (Research on Ozone in the Stratosphere and its Evolution) model, both being Eulerian models, show that their formation is due to adiabatic transport processes. Here, the impact of mixing on the development of these streamers is investigated. These streamers were simulated with the CLaMS model (Chemical Lagrangian Model of the Stratosphere), a Lagrangian model, using N2O as long-lived tracer. Using several different initialisations the results were compared to the KASIMA simulations and CRISTA (Cryogenic Infrared Spectrometer and Telescope for the Atmosphere) observations. Further, since the KASIMA model was employed to derive a 9-year climatology, the quality of the reproduction of streamers from such a study was tested by the comparison of the KASIMA results with CLaMS and CRISTA. The streamers are reproduced well for the Northern Hemisphere in the simulations of CLaMS and KASIMA for the 6 November 1994. However, in the CLaMS simulation a stronger filamentation is found while larger discrepancies between KASIMA and CRISTA were found especially for the Southern Hemisphere. Further, compared to the CRISTA observations the mixing ratios of N2O are in general underestimated in the KASIMA simulations. An improvement of the simulations with KASIMA was obtained for a simulation time according to the length of the CLaMS simulation. To quantify the differences between the simulations with CLaMS and KASIMA, and the CRISTA observations, the probability density function technique (PDF) is used to interpret the tracer distributions. While in the PDF of the KASIMA simulation the small scale structures observed by CRISTA are smoothed out due to the numerical diffusion in the model, the PDFs derived from CRISTA observations can be reproduced by CLaMS by optimizing the mixing parameterisation. Further, this procedure gives information on small-scale variabilities not resolved by the CRISTA observations.

CO2 and Water Activation on Ceria Nanocluster Modified TiO2 Rutile (110)

2018 ◽  
Author(s):  
Michael Nolan ◽  
Stephen Rhatigan
Keyword(s):  
Surface Modification ◽  
Oxygen Vacancy ◽  
Density Functional ◽  
Energy Gap ◽  
Light Response ◽  
Surface Reactivity ◽  
Coulomb Interactions ◽  
Water Activation ◽  
Carrier Separation ◽  
The Impact

Surface modification of TiO<sub>2</sub> with metal oxide nanoclusters is a strategy for the development of new photocatalyst materials. We have studied modification of the (110) surface of rutile TiO<sub>2</sub> with ceria nanoclusters using density functional theory corrected for on-site Coulomb interactions (DFT+U). We focus on the impact of surface modification on key properties governing the performance of photocatalysts, including light absorption, photoexcited charge carrier separation, reducibility and surface reactivity. Our results show that adsorption of the CeO<sub>2</sub> nanoclusters, with compositions Ce<sub>5</sub>O<sub>10</sub> and Ce<sub>6</sub>O<sub>­12</sub>, is favourable at the rutile (110) surface and that the nanocluster-surface composites favour non-stoichiometry in the adsorbed ceria so that reduced Ce ions will be present in the ground state. The presence of reduced Ce ions and low coordinated O sites in the nanocluster lead to the emergence of energy states in the energy gap of the TiO<sub>2</sub> host, which potentially enhance the visible light response. We show, through an examination of oxygen vacancy formation, that the composite systems are reducible with moderate energy costs. Photoexcited electrons and holes localize on Ce and O sites of the supported nanoclusters. The interaction of CO<sub>2</sub> and H<sub>2</sub>O is favourable at multiple sites of the reduced CeO<sub>x</sub>-TiO<sub>2</sub> composite surfaces. CO<sub>2</sub> adsorbs and activates, while H<sub>2</sub>O spontaneously dissociates at oxygen vacancy sites.

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