Using the requirement of Möbius invariance of ${\cal N}$=4 SYM amplitudes in the Regge limit we restore the conformal NLO BFKL kernel out of the eigenvalues known from the forward NLO BFKL result.
Complete NLO BFKL impact factors for quarkonium hadroproduction in NRQCD: the case of ${}^1S_0^{[1]}$, ${}^1S_0^{[8]}$, and ${}^3S_1^{[8]}$ states
National Centre for Nuclear Research(国家核研究中心);Université Paris-Saclay, CNRS/IN2P3, IJCLab(巴黎萨克雷大学,法国国家科学研究中心/欧洲核子研究组织,IJCLab);Physics Department, Ben-Gurion University of the Negev(内盖夫本古里安大学物理系)
We investigate whether NLO BFKL evolution is capable to describe the energy dependence of the exclusive photo-production cross-section of vector mesons $J/Ψ$ and $Υ$ on protons. Our description is based on available NLO BFKL fits of the proton impact factor in inclusive DIS, which allow us to construct the necessary scattering amplitude at zero momentum transfer $t=0$. Assuming an exponential drop-off with $t$, this result allows us to calculate the exclusive photoproduction cross-section. Comparing our results with both HERA data (measured by H1 and ZEUS collaborations in $ep$ collision) and …
In this paper, we show (i) that the NLO corrections do not change the power-like decrease of the scattering amplitude at large impact parameter ($b^2 \,>\,r^2 \exp\left( 2\bar(α}_S η(1 + 4 \barα_S)\right)$, where $r$ denotes the size of scattering dipole and $η\,=\,\ln(1/x_{Bj})$ for DIS), and, therefore, they do not resolve the inconsistency with unitarity; and (ii) they lead to an oscillating behaviour of the scattering amplitude atlarge $b$, in direct contradiction with the unitarity constraints. However, from the more practical point of view, the NLO estimates give a faster decrease of the…
New evidence for the rapidity evolution in Mueller-Navelet dijet production: BFKL, Sudakov, and RG-invariance
Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research(鲍里索夫理论物理实验室,核物理研究所);Physics Department, Ben-Gurion University of the Negev(内盖夫本-古里安大学物理系);Samara National Research University(萨马拉国立研究大学)
DGLAP and BFKL equations are among the cornestones of the contemporary QCD. Moreover, they also played an important role in the recent studies of integrability structure of $\mathcal{N}=4$ SYM. Here, we review the results obtained along this way together with a brief account of approaches and methods used.
We analyze a modification of the BFKL kernel for the adjoint representation of the colour group in the maximally supersymmetric (N=4) Yang-Mills theory in the limit of a large number of colours, related to the modification of the eigenvalues of the kernel suggested by S. Bondarenko and A. Prygarin in order to reach the Hermitian separability of the eigenvalues. We restore the modified kernel in the momentum space. It turns out that the modification is related only to the real part of the kernel and that the correction to the kernel can not be presented by a single analytic function in the enti…
We review the applications of the Quantum Spectral Curve (QSC) method to the Regge (BFKL) limit in N=4 supersymmetric Yang-Mills theory. QSC, based on quantum integrability of the AdS$_5$/CFT$_4$ duality, was initially developed as a tool for the study of the spectrum of anomalous dimensions of local operators in the N=4 SYM in the planar, $N_c\to\infty$ limit. We explain how to apply the QSC for the BFKL limit, which requires non-trivial analytic continuation in spin $S$ and extends the initial construction to non-local light-ray operators. We give a brief review of high precision non-perturb…
In this paper, we use the re-summation procedure, suggested in Refs.\cite{DIMST,SALAM,SALAM1,SALAM2}, to fix the BFKL kernel in the NLO. However, we suggest a different way to introduce th non-linear corrections in the saturation region, which is based on the leading twist non-linear equation. In the kinematic region:$τ\,\equiv\,r^2 Q^2_s(Y)\,\leq\,1$ , where $r$ denotes the size of the dipole, $Y$ its rapidity and $Q_s$ the saturation scale, we found that the re-summation contributes mostly to the leading twist of the BFKL equation. Assuming that the scattering amplitude is small, we suggest …
We find the eigenvalue of the kernel of BFKL equation in the next-to-next-to-next-to-leading logarithm approximation (NNNLLA) in the planar N=4 SYM theory by using the quantum spectral curve to compute values at fixed spin, and reconstructing the general result using the LLL-algorithm, which also was used for the reconstruction of the general result for the intercept function for arbitrary conformal spin at fourth order, computed earlier in paper 1802.06908 up to the rational part. We have found, that a new type of harmonic sums enter into results. Those sums have the argument multiplied by fa…
We present a determination of the parton distribution functions of the proton in which NLO and NNLO fixed-order calculations are supplemented by NLLx small-x resummation. Deep inelastic structure functions are computed consistently at NLO+NLLx or NNLO+NLLx, while for hadronic processes small-x resummation is included only in the PDF evolution, with kinematic cuts introduced to ensure the fitted data lie in a region where the fixed-order calculation of the hard cross-sections is reliable. In all other respects, the fits use the same methodology and are based on the same global dataset as the re…