scholarly journals Longitudinal momentum fraction X[sub L] for two high P[sub t] protons in pp→ppX reaction

2000 ◽  
Author(s):  
D. Zhalov
Keyword(s):  
Longitudinal Momentum ◽  
Momentum Fraction ◽  
Longitudinal Momentum Fraction

scholarly journals T-odd generalized and quasi transverse momentum dependent parton distribution in a scalar spectator model

2020 ◽  
Vol 80 (9) ◽  
Author(s):  
Xuan Luo ◽  
Hao Sun
Keyword(s):  
Transverse Momentum ◽  
Total Momentum ◽  
Longitudinal Momentum ◽  
Momentum Fraction ◽  
Parton Distributions ◽  
Transverse Momentum Dependent ◽  
Longitudinal Momentum Fraction ◽  
Generalized Parton Distributions ◽  
Active Quark ◽  
Spectator Model

AbstractGeneralized transverse momentum dependent parton distributions (GTMDs), as mother funtions of transverse momentum dependent parton distributions (TMDs) and generalized parton distributions (GPDs), encode the most general parton structure of hadrons. We calculate four twist-two time reversal odd GTMDs of pion in a scalar spectator model. We study the dependence of GTMDs on the longitudinal momentum fraction x carried by the active quark and the transverse momentum $$|\vec k_T|$$ | k → T | for different values of skewness $$\xi $$ ξ defined as the longitudinal momentum transferred to the pion as well as the total momentum $$|\vec \Delta _T|$$ | Δ → T | transferred to the pion. In addition, the quasi-TMDs and quasi-GPDs of pion have also been investigated in this paper.

scholarly journals On systematic effects in the numerical solutions of the JIMWLK equation

2021 ◽  
Vol 81 (7) ◽  
Author(s):  
Salvatore Calì ◽  
Krzysztof Cichy ◽  
Piotr Korcyl ◽  
Piotr Kotko ◽  
Krzysztof Kutak ◽  
...  
Keyword(s):  
Numerical Solutions ◽  
High Energy ◽  
Gluon Density ◽  
Longitudinal Momentum ◽  
Coupling Constant ◽  
Longitudinal Momentum Fraction ◽  
Running Coupling ◽  
Systematic Effects ◽  
Gluon Distributions ◽  
Comprehensive Study

AbstractIn the high energy limit of hadron collisions, the evolution of the gluon density in the longitudinal momentum fraction can be deduced from the Balitsky hierarchy of equations or, equivalently, from the nonlinear Jalilian–Marian–Iancu–McLerran–Weigert–Leonidov–Kovner (JIMWLK) equation. The solutions of the latter can be studied numerically by using its reformulation in terms of a Langevin equation. In this paper, we present a comprehensive study of systematic effects associated with the numerical framework, in particular the ones related to the inclusion of the running coupling. We consider three proposed ways in which the running of the coupling constant can be included: “square root” and “noise” prescriptions and the recent proposal by Hatta and Iancu. We implement them both in position and momentum spaces and we investigate and quantify the differences in the resulting evolved gluon distributions. We find that the systematic differences associated with the implementation technicalities can be of a similar magnitude as differences in running coupling prescriptions in some cases, or much smaller in other cases.

scholarly journals Leading jets and energy loss

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Duff Neill ◽  
Felix Ringer ◽  
Nobuo Sato
Keyword(s):  
Energy Loss ◽  
Cross Sections ◽  
Evolution Equations ◽  
Average Energy ◽  
Longitudinal Momentum ◽  
Longitudinal Momentum Fraction ◽  
Inclusive Jets ◽  
Jet Energy ◽  
The Difference ◽  
Additional Reference

Abstract The formation and evolution of leading jets can be described by jet functions which satisfy non-linear DGLAP-type evolution equations. Different than for inclusive jets, the leading jet functions constitute normalized probability densities for the leading jet to carry a longitudinal momentum fraction relative to the initial fragmenting parton. We present a parton shower algorithm which allows for the calculation of leading-jet cross sections where logarithms of the jet radius and threshold logarithms are resummed to next-to-leading logarithmic (NLL′) accuracy. By calculating the mean of the leading jet distribution, we are able to quantify the average out-of-jet radiation, the so-called jet energy loss. When an additional reference scale is measured, we are able to determine the energy loss of leading jets at the cross section level which is identical to parton energy loss at leading-logarithmic accuracy. We identify several suitable cross sections for an extraction of the jet energy loss and we present numerical results for leading subjets at the LHC. In addition, we consider hemisphere and event-wide leading jets in electron-positron annihilation similar to measurements performed at LEP. Besides the average energy loss, we also consider its variance and other statistical quantities such as the KL divergence which quantifies the difference between quark and gluon jet energy loss. We expect that our results will be particularly relevant for quantifying the energy loss of quark and gluon jets that propagate through hot or cold nuclear matter.

scholarly journals Saturation effects in SIDIS at very forward rapidities

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
E. Iancu ◽  
A. H. Mueller ◽  
D. N. Triantafyllopoulos ◽  
S. Y. Wei
Keyword(s):  
Inelastic Scattering ◽  
Cross Section ◽  
Cross Sections ◽  
Virtual Photon ◽  
Large Fraction ◽  
Quark Distribution ◽  
High Energy ◽  
Longitudinal Momentum ◽  
Black Disk ◽  
Gluon Saturation

Abstract Using the dipole picture for electron-nucleus deep inelastic scattering at small Bjorken x, we study the effects of gluon saturation in the nuclear target on the cross-section for SIDIS (single inclusive hadron, or jet, production). We argue that the sensitivity of this process to gluon saturation can be enhanced by tagging on a hadron (or jet) which carries a large fraction z ≃ 1 of the longitudinal momentum of the virtual photon. This opens the possibility to study gluon saturation in relatively hard processes, where the virtuality Q2 is (much) larger than the target saturation momentum $$ {Q}_s^2 $$ Q s 2 , but such that z(1 − z)Q2 ≲ $$ {Q}_s^2 $$ Q s 2 . Working in the limit z(1 − z)Q2 ≪ $$ {Q}_s^2 $$ Q s 2 , we predict new phenomena which would signal saturation in the SIDIS cross-section. For sufficiently low transverse momenta k⊥ ≪ Qs of the produced particle, the dominant contribution comes from elastic scattering in the black disk limit, which exposes the unintegrated quark distribution in the virtual photon. For larger momenta k⊥ ≳ Qs, inelastic collisions take the leading role. They explore gluon saturation via multiple scattering, leading to a Gaussian distribution in k⊥ centred around Qs. When z(1 − z)Q2 ≪ Q2, this results in a Cronin peak in the nuclear modification factor (the RpA ratio) at moderate values of x. With decreasing x, this peak is washed out by the high-energy evolution and replaced by nuclear suppression (RpA< 1) up to large momenta k⊥ ≫ Qs. Still for z(1 − z)Q2 ≪ $$ {Q}_s^2 $$ Q s 2 , we also compute SIDIS cross-sections integrated over k⊥. We find that both elastic and inelastic scattering are controlled by the black disk limit, so they yield similar contributions, of zeroth order in the QCD coupling.

Recoil longitudinal momentum andQ-value measurements in electron-capture processes of fast multiply charged ions colliding with He

1995 ◽  
Vol 51 (5) ◽  
pp. 3718-3725 ◽  
Author(s):  
W. Wu ◽  
K. L. Wong ◽  
C. L. Cocke ◽  
J. P. Giese ◽  
E. C. Montenegro
Keyword(s):  
Electron Capture ◽  
Longitudinal Momentum ◽  
Multiply Charged Ions ◽  
Multiply Charged ◽  
Charged Ions

scholarly journals One-loop matching for spin-dependent quasi-TMDs

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Markus A. Ebert ◽  
Stella T. Schindler ◽  
Iain W. Stewart ◽  
Yong Zhao
Keyword(s):  
Spin Structure ◽  
Wilson Line ◽  
Three Dimensional ◽  
Distribution Functions ◽  
Longitudinal Momentum ◽  
Loop Order ◽  
Parton Distribution Functions ◽  
Transverse Momentum Dependent ◽  
Unique Probe ◽  
Transverse Position

Abstract Transverse momentum dependent parton distribution functions (TMDPDFs) provide a unique probe of the three-dimensional spin structure of hadrons. We construct spin-dependent quasi-TMDPDFs that are amenable to lattice QCD calculations and that can be used to determine spin-dependent TMDPDFs. We calculate the short-distance coefficients connecting spin-dependent TMDPDFs and quasi-TMDPDFs at one-loop order. We find that the helicity and transversity distributions have the same coefficient as the unpolarized TMDPDF. We also argue that the same is true for pretzelosity and that this spin universality of the matching will hold to all orders in αs. Thus, it is possible to calculate ratios of these distributions as a function of longitudinal momentum and transverse position utilizing simpler Wilson line paths than have previously been considered.

scholarly journals Comparison of different approaches to the longitudinal momentum spread after tunnel ionization

2013 ◽  
Vol 46 (12) ◽  
pp. 125601 ◽  
Author(s):  
C Hofmann ◽  
A S Landsman ◽  
C Cirelli ◽  
A N Pfeiffer ◽  
U Keller
Keyword(s):  
Longitudinal Momentum ◽  
Momentum Spread ◽  
Tunnel Ionization

scholarly journals Triple-pomeron amplitude in the effective action approach

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
M. A. Braun
Keyword(s):  
Momentum Transfer ◽  
Cross Section ◽  
Imaginary Part ◽  
Effective Action ◽  
High Mass ◽  
Longitudinal Momentum ◽  
Double Scattering ◽  
Composite Target ◽  
Scattering Cross ◽  
Simple Factor

Abstract In the effective action approach the imaginary part of the triple pomeron amplitude is calculated. The found dependence on the longitudinal momentum transfer $$e_{-}$$e- is found to separate as a simple factor $$1/|e_{-}|$$1/|e-|. This result is used to calculate the high-mass diffraction on a hadron and double scattering cross-section off a composite target.

Towards multi-scale modelling of complex liquids using hybrid particle—continuum schemes

2008 ◽  
Vol 222 (5) ◽  
pp. 769-776 ◽  
Author(s):  
R Delgado-Buscalioni ◽  
P V Coveney ◽  
G De Fabritiis
Keyword(s):  
Landau Theory ◽  
Coarse Graining ◽  
Longitudinal Momentum ◽  
Hybrid Technique ◽  
Sound Waves ◽  
Multi Scale ◽  
Complex Liquids ◽  
Transversal Shear ◽  
Scale Modelling ◽  
Molecular Nature

Owing to the interplay between molecular and mesoscopic processes, the modelling and simulation of complex liquids at nano- and micron-scales require a multi-scale approach. A hybrid technique is proposed to handle multi-scale phenomena, which retains the full molecular nature of the system where it is of interest while coarse-graining it elsewhere. The method couples molecular dynamics (MD) and fluctuating hydrodynamics (FH) based on the Landau theory. Mean flows involving transport of transversal (shear) and longitudinal momentum (sound) are coupled across the interface of both MD and FH domains. Hydrodynamic fluctuations of mass and momentum are transferred, preserving consistency with hydrodynamics and thermodynamics. Here the hybrid method is illustrated by studying the reflection of water sound waves against a lipid (dimyristoylphosphatidylcholine) monolayer.

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