Beyond DGLAP improved saturation model Boroun, G. R.
The European physical journal. C, Particles and fields,
01/2023, Letnik:
83, Številka:
1
Journal Article
Recenzirano
Odprti dostop
We present a modification of the DGLAP improved saturation model with respect to the nonlinear correction (NLC). The GLR-MQ improved saturation model is considered by employing the parametrization of ...proton structure function due to the Laplace transforms method, which preserves its behavior success in the low and high
Q
2
regions. We show that the geometric scaling holds for the GLR-MQ improved model in a wide kinematic region
r
Q
s
. These results are comparable with other models in a wide kinematic region
r
Q
s
. The behavior of the dipole cross sections, with respect to the GLR-MQ improved saturation model, are comparable with the Color Glass Condensate (CGC) model. The model describes the dipole cross sections in the inclusive and diffractive processes. We also compare the nonlinear corrections to the impact-parameter dependent saturation (IP-Sat) model with the impact-parameter dependent color glass condensate (b-CGC) dipole model. Finally, we consider the linear and nonlinear corrections to the IP Non-Sat model. These results provide a benchmark for further investigation of QCD at small
x
in future experiments such as the Large Hadron Collider and Future Circular Collider projects.
We show that the geometric scaling of the dipole cross section can be explained using standard DGLAP perturbative evolution. The DGLAP-improved saturation model due to the Laplace transform method is ...considered at LO and NNLO approximations from the experimental data by relying on a Froissart-bounded parametrization of
F
2
(
x
,
Q
2
)
. These results are comparable with the Golec-Biernat–W
u
¨
sthoff (GBW) model in a wide kinematic region
r
Q
s
which takes into account charm mass. The successful description of
σ
dip
(
x
,
r
)
/
σ
0
and
σ
dip
(
r
Q
s
)
/
σ
0
are presented.
We present nonlinear corrections (NLCs) to the distribution functions at low values of
x
and
Q
2
using the parametrization
F
2
(
x
,
Q
2
)
and
F
L
(
x
,
Q
2
)
. We use a direct method to extract ...nonlinear corrections to the ratio of structure functions and the reduced cross section in the next-to-next-to-leading order (NNLO) approximation with respect to the parametrization method (PM). Comparisons between the nonlinear results with the bounds in the color dipole model (CDM) and HERA data indicate the consistency of the nonlinear behavior of the gluon distribution function at low
x
and low
Q
2
. The nonlinear longitudinal structure functions are comparable with the H1 Collaboration data in a wide range of
Q
2
values. Consequently, the nonlinear corrections at NNLO approximation to the reduced cross sections at low and moderate
Q
2
values show good agreement with the HERA combined data. These results at low
x
and low
Q
2
can be applied to the LHeC region for analyses of ultra-high-energy processes.
In this paper, we have investigated the importance of quark charm in nuclear structure functions in the color dipole model at small x. The charm structure function per nucleon F2cA/A for light and ...heavy nuclei in a wide range of transverse separations r with renormalization and factorization scales is considered. Bounds on the ratio F2cA/AF2A for nuclei are well described with respect to the electron-ion future colliders kinematic range, i.e., EIC and EIcC colliders.
The gluon distribution is obtained from the Golec-Biernat–W
u
¨
sthoff (GBW) and Bartels, Golec-Biernat, and Kowalski (BGK) models at low
x
. We derive analytical results for the unintegrated color ...dipole gluon distribution function at small transverse momentum, which provides useful information to constrain the
k
t
-shape of the unintegrated gluon distribution in comparison with the unintegrated gluon distribution (UGD) models. The longitudinal proton structure function
F
L
(
x
,
Q
2
)
from the
k
t
factorization scheme, using the unintegrated gluon density, is computed. We compare the predictions for the on-shell and twist-2 corrections with the HERA data and the CJ15 parameterization method for
F
L
. We show that this method describes very well the experimental data within the on-shell and twist-2 framework. Effects of parameters on
F
L
, where charm contribution is taken into account, are investigated. These results are in good agreement with the data at fixed
W
.
Predictions of the top-pair production cross section in electron-proton (ep) collisions at the future circular collider hadron-electron (FCC-he) and the large hadron electron collider (LHeC) in the ...leading order (LO) and the next-to-leading order (NLO) approximations in perturbative quantum chromodynamics (QCD) are presented. Numerical results for the top structure functions and the ratio of structure functions are computed at the renormalization scale μ2=Q2+4mt2 in the collinear generalized double asymptotic scaling (DAS) approach. These results are presented in terms of the effective parameters of the parameterization of F2(x,Q2), where relying on a Froissart-bounded. These quantitative results can be important for future collider experiments at the center-of-mass energy frontier and the improvement of the phenomenological models for the development of the cosmic ray cascades in ultra-high-energy domain. We obtained the uncertainties because of the power-law behavior x−Δ of the collinear parton distribution functions (PDFs), the factorization, and renormalization scales, on the top properties at high inelasticity for the FCC-he center-of-mass (CM) energy at the NLO approximation.
The proposed linear and nonlinear behavior for the top structure function at the LHeC is considered. We present the conditions necessary to predict the top structure function F2t(x,Q2) with respect ...to the different predictions for the behavior of the gluon at low x.
The correspondence between the gluon density behavior of the color dipole picture (CDP) and the two-Pomeron approach at low
x
deep inelastic scattering is considered. For photon virtualities of
GeV
2
..., the results for the parametrization and CDP models are defined by the CDP asymptotic limit and are compatible with the soft and hard-Pomeron approach. These results show that the hard-Pomeron trajectory does not guarantee converging towards the asymptotic representation at low and large
(
GeV
2
) values in a wide range of the virtual-photon–proton energy squared. The gluon distributions can be obtained directly in terms of the proton structure functions and the running coupling and compared with the results from the M. Gluck, P. Jimenez-Delgado and E. Reya (GJR) and A. Martin, W. Stirling, R. Thorne, and G. Watt (MSTW) parametrizations.
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