scholarly journals Saturation scale fluctuations and multiparticle rapidity correlations

2016 ◽  
Vol 94 (4) ◽  
Author(s):  
Adam Bzdak ◽  
Kevin Dusling
Keyword(s):  
Saturation Scale

Colour Image Enhancement using Perceptual Saturation and Vividness

2019 ◽  
Vol 2019 (1) ◽  
pp. 243-246
Author(s):  
Muhammad Safdar ◽  
Noémie Pozzera ◽  
Jon Yngve Hardeberg
Keyword(s):  
Image Quality ◽  
Image Enhancement ◽  
Test Performance ◽  
Appearance Model ◽  
Colour Space ◽  
Categorical Judgment ◽  
Saturation Scale ◽  
Colour Image ◽  
Colour Appearance ◽  
Future Test

A perceptual study was conducted to enhance colour image quality in terms of naturalness and preference using perceptual scales of saturation and vividness. Saturation scale has been extensively used for this purpose while vividness has been little used. We used perceptual scales of a recently developed colour appearance model based on Jzazbz uniform colour space. A two-fold aim of the study was (i) to test performance of recently developed perceptual scales of saturation and vividness compared with previously used hypothetical models and (ii) to compare performance and chose one of saturation and vividness scales for colour image enhancement in future. Test images were first transformed to Jzazbz colour space and their saturation and vividness were then decreased or increased to obtain 6 different variants of the image. Categorical judgment method was used to judge preference and naturalness of different variants of the test images and results are reported.

scholarly journals High energy QCD: multiplicity dependence of quarkonia production

2021 ◽  
Vol 81 (2) ◽  
Author(s):  
E. Gotsman ◽  
E. Levin
Keyword(s):  
Experimental Data ◽  
Gluon Fusion ◽  
High Energy ◽  
Saturation Scale

AbstractIn this paper we propose an approach which demonstrates the dependence of quarkonia production on the multiplicity of the accompanying hadrons. Our approach is based on the three gluon fusion mechanism, without assuming the multiplicity dependence of the saturation scale. We show, that we describe the experimental data, which has a dependence that is much steeper than the multiplicity of the hadrons.

scholarly journals Comparison of improved TMD and CGC frameworks in forward quark dijet production

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Hirotsugu Fujii ◽  
Cyrille Marquet ◽  
Kazuhiro Watanabe
Keyword(s):  
Azimuthal Angle ◽  
High Energy ◽  
Color Glass ◽  
Dijet Production ◽  
Proton Proton ◽  
Saturation Scale ◽  
Wide Range ◽  
Factorization Formula ◽  
Leading Term ◽  
Multi Body

Abstract For studying small-x gluon saturation in forward dijet production in high-energy dilute-dense collisions, the improved TMD (ITMD) factorization formula was recently proposed. In the Color Glass Condensate (CGC) framework, it represents the leading term of an expansion in inverse powers of the hard scale. It contains the leading-twist TMD factorization formula relevant for small gluon’s transverse momentum kt, but also incorporates an all-order resummation of kinematical twists, resulting in a proper matching to high-energy factorization at large kt. In this paper, we evaluate the accuracy of the ITMD formula quantitatively, for the case of quark dijet production in high-energy proton-proton(p+p) and proton-nucleus (p+A) collisions at LHC energies. We do so by comparing the quark-antiquark azimuthal angle ∆ϕ distribution to that obtained with the CGC formula. For a dijet with each quark momentum pt much larger than the target saturation scale, Qs, the ITMD formula is a good approximation to the CGC formula in a wide range of azimuthal angle. It becomes less accurate as the jet pt’s are lowered, as expected, due to the presence of genuine higher-twists contributions in the CGC framework, which represent multi-body scattering effects absent in the ITMD formula. We find that, as the hard jet momenta are lowered, the accuracy of ITMD start by deteriorating at small angles, in the high-energy-factorization regime, while in the TMD regime near ∆ϕ = π, very low values of pt are needed to see differences between the CGC and the ITMD formula. In addition, the genuine twists corrections to ITMD become visible for higher values of pt in p + A collisions, compared to p+p collisions, signaling that they are enhanced by the target saturation scale.

NONLINEAR EVOLUTION AT SMALL x WITH IMPACT PARAMETER DEPENDENCE

2011 ◽  
Vol 04 ◽  
pp. 67-73
Author(s):  
JEFFREY J. BERGER
Keyword(s):  
Evolution Equation ◽  
Structure Function ◽  
Numerical Solution ◽  
Impact Parameter ◽  
Qualitative Agreement ◽  
Nonlinear Evolution ◽  
Hera Data ◽  
Saturation Scale ◽  
Running Coupling ◽  
Small X

Nonlinear evolution at small x was evaluated numerically with full dependence on impact parameter using the BK equation. several distinct behaviors were found and are presented for the leading logarithmic kernel in the BK evolution equation with both fixed and running coupling. The value of the saturation scale at various dipole sizes was found to agree with analytic expectations. Calculation of the F2structure function from the numerical solution of the evolution with running coupling were then compared to the HERA data and qualitative agreement found. The agreement is improved with inclusion of soft contributions and these are discussed.

scholarly journals The saturation scale and its x-dependence from Λ polarization studies

2009 ◽  
Vol 671 (1) ◽  
pp. 91-98 ◽  
Author(s):  
Daniël Boer ◽  
Andre Utermann ◽  
Erik Wessels
Keyword(s):  
Saturation Scale ◽  
Polarization Studies
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