We determined the effects of the first nonlinear corrections to the gluon distribution using the solution of the QCD nonlinear Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (NLDGLAP) evolution equation at small x. By using a Laplace-transform technique, the behavior of the gluon distribution is obtained by solving the Gribov, Levin, Ryskin, Mueller and Qiu (GLR-MQ) evolution equation with the nonlinear shadowing term incorporated. We show that the strong rise that is corresponding to the linear QCD evolution equations at small x can be tamed by screening effects. Consequently, the nonlinear effects for the gluon distributions are calculated and compared with the results for the integrated gluon density from the Balitsky-Kovchegov (BK) equation. The resulting analytic expression allows us to predict the shadowing correction to the logarithmic derivative $F_{2}(x,Q^{2})$ with respect to $ln Q^{2}$ and to compare the results with H1 data and a QCD analysis fit.
Determination of proton parton distribution functions is present under the dynamical parton model assumption by applying DGLAP equations with GLR-MQ-ZRS corrections. We provide two data sets, referred as IMParton16, which are from two different nonperturbative inputs. One is the naive input of three valence quarks and the other is the input of three valence quarks with flavor-asymmetric sea components. Basically, both data sets are compatible with the experimental measurements at high scale ($Q^2>2$ GeV$^2$). Furthermore, our analysis shows that the input with flavor-asymmetric sea components …
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 $rQ_{s}$. These results are comparable with other models in a wide kinematic region $rQ_{s}$. The behavior of the dipole cross sections, with respect to the GLR-MQ …
We obtain a pair of second order differential equations in two variables $x$ and $t$ from the coupled DGLAP QCD evolution equations at small $x$ using the standard Taylor series expansion method.To that end we keep terms upto $O(x^2 )$.We use the standard assumption about the relationship between the singlet Structure Function and the gluon distributions available in current literature. We solve the taylor approximated $O(x)$ DGLAP equations by Lagrange's auxiliary method and $O(x^2)$ equation by Method of Separation of Variables and then show that the two solutions obtained in each for $O(x)$…
In this paper we have solved the nonlinear Gribov-Levin-Ryskin-Mueller-Qiu (GLR-MQ) evolution equation for gluon distribution function G(x,Q^2) and studied the effects of the nonlinear GLR-MQ corrections to the Leading Order (LO) Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) evolution equations. Here we incorporate a Regge like behaviour of gluon distribution function to obtain the solution of GLR-MQ evolution equation. We have also investigated the Q^2-dependence of gluon distribution function from the solution of GLR-MQ evolution equation. Moreover it is interesting to observe from our …
The corrections of gluon fusion to the DGLAP and BFKL equations are discussed in a united partonic framework. The resulting nonlinear evolution equations are the well-known GLR-MQ-ZRS equation and a new evolution equation. Using the available saturation models as input, we find that the new evolution equation has the chaos solution with positive Lyaponov exponents in the perturbative range. We predict a new kind of shadowing caused by chaos, which blocks the QCD evolution in a critical small $x$ range. The blocking effect in the evolution equation may explain the Abelian gluon assumption and e…
Nonlinear effects and the behavior of total hadronic and photonic cross sections
在这项工作中，我们使用eikonalized微型射流模型的影响，第一非线性修正的DGstrom方程被考虑在内。来自胶子复合效应的贡献被包括在DGREN +GLRMQ方法的自由质子的饱和模型的背景下。该模型的参数是固定的，以适应总$pp$和$\bar p p$截面，包括最近的数据从大型强子对撞机，HiRes和P.俄歇合作。Glauber和多重散射近似，然后用来描述包容性的非弹性质子-空气截面。利用矢量介子占优模型和加性夸克模型，在不改变已知参数的情况下，得到了光生截面。我们展示并讨论了我们的主要结果，以及饱和效应在非常高能量下的强子和光子截面行为中的意义。
In this work we have suggested a solution of the Gribov-Levin-Ryskin-Mueller-Qiu (GLR-MQ) nonlinear evolution equation at next-to-next-to-leading order (NNLO). The range of $Q^2$ in which we have solved the GLR-MQ equation is Regge region of the range $5 GeV^2 \leq Q^2 \leq 25 GeV^2$ and so we have incorporated the Regge like behavior to obtain $Q^2$ evolution of gluon distribution function $G(x, Q^2)$. We have also checked the sensitivity of our results for different values of correlation radius (R) between two interacting gluons, viz. $R=2 GeV^{-1}$ and $R= 5 GeV^{-1}$ as well as for differe…
We present a phenomenological study of the small-x behaviour of gluon distribution function $G(x,Q^2)$ at next-to-leading order (NLO) and next-to-next-to-leading order(NNLO) in light of the nonlinear Gribov-Ryskin-Levin-Mueller-Qiu (GLR-MQ)evolution equation by keeping the transverse size of the gluons ($\sim 1/Q$) fixed. We consider the NLO and NNLO corrections, of the gluon-gluon spitting function $P_{gg} (z)$ and strong coupling constant $α_s (Q^2)$. We have suggested semi-analytical solutions based on Regge like ansatz of gluon density $G(x,Q^2)$, which are supposed to be valid in the mode…
An analytical solution of the QCD evolution equations for the singlet and gluon distribution is presented. We decouple DGLAP evolution equations into the initial conditions by using a Laplace transform method at $N^{n}LO$ analysis. The relationship between the nonlinear behavior and color dipole model is considered based on an effective exponent behavior at low-$x$ values. We obtain the effective exponent at NLO analysis from the decoupled behavior of the distribution functions. The proton structure function compared with H1 data from the inclusive structure function $F_{2}(x,Q^{2})$ for $x {\…
We present the polarized parton distribution functions from a QCD analysis of the worldwide polarized deep inelastic scattering data, based on the dynamical parton distribution model. All the sea quarks and gluons are dynamically generated from QCD radiations, with the nonperturbative input contains only the polarized valence quark distributions. This approach leads to a simple parametrization, which has only four free parameters. In the analysis, we apply the DGLAP equations with parton-parton recombination corrections. The parameterized nonperturbative input at an extremely low $Q_0^2$ repro…
In the high energy regime, the proton structure consists of a very large number of particles called partons (quarks and gluons) that interact with each other, according to the theory of strong interactions, Quantum Chromodynamics (QCD). Through QCD, the number of partons in the proton is described by equations of parton evolution that depend on kinematic variables. These equations can be linear, the DGLAP equations, and nonlinear, the GLR-MQ equation. We have studied some analytic solutions of the equations of parton evolution. In order to generate the preliminary results, we used an ansatz fo…
In the present article, two analytical solutions based on the Laplace transforms method for the linear and non-linear gluon distribution functions have been presented at low values of $x$. These linear and non-linear methods are presented based on the solutions of the Dokshitzer-Gribov- Lipatov-Altarelli-Parisi (DGLAP) evolution equation and the Gribov-Levin-Ryskin Mueller-Qiu (GLR-MQ) equation at the leading-order accuracy in perturbative QCD respectively. The gluon distributions are obtained directly in terms of the parametrization of structure function $F_{2}(x,Q^{2})$ and its derivative an…
Using the framework that interpolates between the leading power limit of the Color Glass Condensate and the High Energy (or $k_{T}$) factorization we calculate the direct component of the forward dijet production in ultra-peripheral $\mathrm{Pb}$-$\mathrm{Pb}$ collisions at CM energy $5.1\,\mathrm{TeV}$ per nucleon pair. The formalism is applicable when the average transverse momentum of the dijet system $P_{T}$ is much bigger than the saturation scale $Q_{s}$, $P_{T}\gg Q_{s}$, while the imbalance of the dijet system can be arbitrary. The cross section is uniquely sensitive to the Weizsäcker-…
We study experimentally observable signals for nonlinear QCD dynamics in deep inelastic scattering (DIS) at small Bjorken variable $x$ and moderate virtuality $Q^2$, by quantifying differences between the linear Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) evolution and nonlinear evolution with the Balitsky-Kovchegov (BK) equation. To remove the effect of the parametrization freedom in the initial conditions of both equations, we first match the predictions for the DIS structure functions $F_2$ and $F_{\rm L}$ from both frameworks in a region in $x,Q^2$ where both frameworks should provi…
