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We discuss a series of results aimed at bringing saturation physics and gluon tomography into an era of precision. In particular, the NLO treatment of diffractive: 1) exclusive dijet, 2) exclusive longitudinally polarized light vector meson and 3) semi-inclusive single or double hadron photo- or electroproduction with large $p_T$, on a nucleon or a nuclei. Finally, we discuss the more complicated 4) exclusive transversely polarized light vector meson production, which starts at the next-to-leading power and therefore requires a beyond leading twist treatment. This new class of processes provides an access to precision physics of gluon saturation dynamics, with very promising future phenomenological studies at the EIC, or, at the LHC in $p A$ and $A A$ scattering, using Ultra Peripheral Collisions (UPC)., Comment: 6 pages, 2 figures, proceedings of the 31st International Workshop on Deep Inelastic Scattering (DIS2024), 8-12 April 2024, Grenoble, France

We investigate spin-refined partition functions in AdS/CFT using Euclidean gravitational path integrals. We construct phase diagrams for $Z_X = \text{Tr} \big( e^{-\beta H} X \big)$ in various dimensions and for different choices of discrete isometry $X$, discovering rich structures at finite temperature. When $X$ is a reflection, $Z_X$ counts the difference between the number of even- and odd-spin microstates. The high-temperature regime is universally dominated by $\mathcal{CRT}$-twisted black holes in any dimension, and in odd spacetime dimensions we examine whether complex rotating black hole solutions could contribute to spin-refined observables. We also analyze the microcanonical ensemble. There the leading contribution almost always come from rotating black holes, showing that the two ensembles are not equivalent., Comment: 25 pages, 8 figures

We discuss correlators of light fields in heavy states in 3d gravity and holographic 2d CFTs. In the bulk, the propagator of free fields in AdS backgrounds containing a conical defect or a BTZ black hole can be obtained by solving the wave equation, as well as by the method of images. On the boundary, these geometries are sourced by heavy operator insertions, and the propagator is dual to a heavy-light (HHLL) correlator. By matching its expansion in Virasoro blocks to our bulk results, we determine the OPE coefficients of all contributing states in both the s and t channels. In the s channel, these states are excitations of the light field on top of the heavy state, and their OPE coefficients are the amplitudes to create them. The t-channel OPE is dominated by the Virasoro vacuum block, but there is also an infinite family of light two-particle states that contribute to the correlator. The OPE coefficients that couple these states to heavy operators represent their expectation values in heavy backgrounds. We determine them exactly, derive their asymptotic form at large twist, and discuss their behavior near and above the BTZ threshold, where they become thermal one-point functions., Comment: 40 + 12 pages, 10 figures. Comments welcome! v2: added comments and references, and made other minor improvements. Matches published version

We calculate the cross-sections of diffractive single hadron photo- or electroproduction with large $p_T$, on a nucleon or a nucleus in the shockwave formalism. We use the hybrid formalism mixing collinear factorization with high energy small-$x$ factorization with the impact factors computed at next-to-leading order accuracy. We prove the cancellation of divergence and we determine the finite parts of the differential cross-sections. We work in general kinematics such that both photoproduction and leptoproduction are considered. The results can be used to detect saturation effects, at both the future EIC or already at LHC, using Ultra-Peripheral Collisions., Comment: 53 pages, 21 Figures. arXiv admin note: text overlap with arXiv:2211.05774. Final version published on JHEP

We study the Feynman propagator of free scalar fields in $AdS_3$ with a conical defect. The propagator is built by solving the bulk equation of motion, summing over the modes of the field, and taking the boundary limit. We then perform several consistency checks. In the dual CFT, the operator responsible for the defect creates a highly excited state. We consider the exchange of the Virasoro identity block in the heavy-light limit to obtain an expression for the propagator sensitive to the mass of the defect. In $AdS_3/\mathbb{Z}_n$, we treat the propagator by the method of images and in the geodesic approximation. More generally, we argue that long-range correlations of the scalar are suppressed as the defect becomes more massive: we find a continuous phase transition in the correlator at the BTZ threshold and examine its critical behavior. Finally, we apply our results to holographic entanglement entropy using an analogy between our scalars and replica twist fields., Comment: 33 pages, 5 figures, JHEP style. v2: Section 4 was rewritten: an error was corrected that arose from using an approximation that did not apply. The crossing relations are now verified to all orders and do not present a puzzle any longer. The conclusions are updated based on the new calculations. Figures and references added. v3: Number of typos reduced. Supersedes the published version

The cross-sections of diffractive double hadron photo- or electroproduction with large $p_T$, on a nucleon or a nucleus, are calculated to NLO accuracy. A hybrid formalism mixing collinear factorization and high energy small-$x$ factorization, more precisely the shockwave formalism for the latter, is used to derive the results. The cancellation of divergences is explicitly shown, and the finite parts of the NLO differential cross-sections are found. We work in arbitrary kinematics such that both photoproduction and leptoproduction are considered. The results are therefore usable, to detect saturation effects, at both the future EIC or already at LHC, using Ultra Peripheral Collisions., Comment: 80 pages, 9 figures, few references added

We compute the next-leading-order cross-sections for diffractive electro- or photoproduction of a pair of hadrons with large $p_T$, out of a nucleus or a nucleon. A hybrid factorization is used, mixing collinear and small-$x$ factorizations, more precisely shockwave formalism. We demonstrate the cancellation of divergences and extract the finite parts of the differential cross-section in general kinematics., Comment: 6 pages, 2 figures. Presented by E. Li at Diffraction and Low-x 2022, Corigliano Calabro, Italy, September 24-30, 2022

We analyze algorithmic and computational aspects of biological phenomena, such as replication and programmed death, in the context of machine learning. We use two different measures of neuron efficiency to develop machine learning algorithms for adding neurons to the system (i.e. replication algorithm) and removing neurons from the system (i.e. programmed death algorithm). We argue that the programmed death algorithm can be used for compression of neural networks and the replication algorithm can be used for improving performance of the already trained neural networks. We also show that a combined algorithm of programmed death and replication can improve the learning efficiency of arbitrary machine learning systems. The computational advantages of the bio-inspired algorithms are demonstrated by training feedforward neural networks on the MNIST dataset of handwritten images., Comment: 17 pages, 5 figures

Material response of real, passive, linear, time-invariant media to external influences is described by complex analytic functions of frequency that can always be written in terms of Stieltjes functions -- a special class of analytic functions mapping complex upper half-plane into itself. Reconstructing such functions from their experimentally measured values at specific frequencies is one of the central problems that we address in this paper. A definitive reconstruction algorithm that produces a certificate of optimality as well as a graphical representation of the uncertainty of reconstruction is proposed. Its effectiveness is demonstrated in the context of the electrochemical impedance spectroscopy., Comment: 37 pages, 6 figures

We pose and resolve a holographic puzzle regarding an apparent violation of causality in AdS/CFT. If a point in the bulk of $AdS$ moves at the speed of light, the boundary subregion that encodes it may need to move superluminally to keep up. With $AdS_3$ as our main example, we prove that the finite extent of the encoding regions prevents a paradox. We show that the length of the minimal-size encoding interval gives rise to a tortoise coordinate on $\mathrm{AdS}$ that measures the nonlocality of the encoding. We use this coordinate to explore circular and radial motion in the bulk before passing to the analysis of bulk null geodesics. For these null geodesics, there is always a critical encoding where the possible violation of causality is barely avoided. We show that in any other encoding, the possible violation is subcritical., Comment: 28 pages, 14 figures

BackgroundClinical monitoring of patients with Parkinson's disease (PD) for cognitive decline is an important element of care. The Montreal Cognitive Assessment (MoCA) has been proposed to be a sensitive tool for assessing cognitive impairment in PD. The aim of our study was to compare the responsiveness of the MoCA to decline in cognition to the responsiveness of the Mini Mental State Examination (MMSE) and the Scales for Outcomes of Parkinson's disease-cognition (SCOPA-Cog).MethodsPD patients without dementia were enrolled at 6 North American movement disorders centers between 2008 and 2011. Participants received annual evaluations including the MoCA, MMSE, and SCOPA-Cog followed by formal neuropsychological testing. The gold standard for change in cognition was defined as the change on the neuropsychological test scores over the annual assessments. The Reliable Change Method was used to provide an estimate of the probability that a given difference score would be obtained by chance. The sensitivity of the MoCA, MMSE, and SCOPA-Cog to change was quantified using receiver operating characteristics (ROC) curves.ResultsOne hundred seventeen patients were included in the analysis. Participants were followed at mean intervals of 11 ± 2 months for a median of 2 (maximum 5) visits. According to the reliable change index, 56 intervals of cognitive testing showed a decline in global cognition. ROC analysis of change in MoCA, MMSE, and SCOPA-Cog global scores compared to gold standard testing found an area under the curve (AUC) of 0.55 (95% CI 0.48-0.62), 0.56 (0.48-0.63), and 0.63 (0.55-0.70) respectively. There were no significant differences in the AUCs across the tests. The sensitivity of the MoCA, MMSE, and SCOPA-Cog to change at various thresholds for decline in scores reached a maximum of 71% for a cut-off of 1 point change on the SCOPA-Cog.ConclusionUsing neuropsychological testing as a gold standard comparator, the performance of the MoCA, MMSE, and SCOPA-Cog for d

BackgroundClinical monitoring of patients with Parkinson's disease (PD) for cognitive decline is an important element of care. The Montreal Cognitive Assessment (MoCA) has been proposed to be a sensitive tool for assessing cognitive impairment in PD. The aim of our study was to compare the responsiveness of the MoCA to decline in cognition to the responsiveness of the Mini Mental State Examination (MMSE) and the Scales for Outcomes of Parkinson's disease-cognition (SCOPA-Cog).MethodsPD patients without dementia were enrolled at 6 North American movement disorders centers between 2008 and 2011. Participants received annual evaluations including the MoCA, MMSE, and SCOPA-Cog followed by formal neuropsychological testing. The gold standard for change in cognition was defined as the change on the neuropsychological test scores over the annual assessments. The Reliable Change Method was used to provide an estimate of the probability that a given difference score would be obtained by chance. The sensitivity of the MoCA, MMSE, and SCOPA-Cog to change was quantified using receiver operating characteristics (ROC) curves.ResultsOne hundred seventeen patients were included in the analysis. Participants were followed at mean intervals of 11 ± 2 months for a median of 2 (maximum 5) visits. According to the reliable change index, 56 intervals of cognitive testing showed a decline in global cognition. ROC analysis of change in MoCA, MMSE, and SCOPA-Cog global scores compared to gold standard testing found an area under the curve (AUC) of 0.55 (95% CI 0.48-0.62), 0.56 (0.48-0.63), and 0.63 (0.55-0.70) respectively. There were no significant differences in the AUCs across the tests. The sensitivity of the MoCA, MMSE, and SCOPA-Cog to change at various thresholds for decline in scores reached a maximum of 71% for a cut-off of 1 point change on the SCOPA-Cog.ConclusionUsing neuropsychological testing as a gold standard comparator, the performance of the MoCA, MMSE, and SCOPA-Cog for d

In the framework of the QCD shock-wave approach, we review our results on the description of diffractive production of various final states (jets, meson) at next-to-leading order. This is applied to exclusive diffractive dijet electroproduction at HERA., Comment: 6 pages, 3 figures, proceedings of Light Cone 2019 (LC 2019), 16-20 September 2019, Ecole Polytechnique, Palaiseau, France

A method for measuring the average longitudinal polarization of the electron beam at an electron-positron collider operating near the $J/\psi$ resonance is proposed. The method utilizes the differential cross-section of $J/\psi\to [\Lambda\to p\pi^-][\bar{\Lambda}\to\bar{p}\pi^+]$ decay. It can be used to measure the average longitudinal polarization of electrons with the statistical precision better than $10^{-3}$ at a Super Charm-Tau factory operating at the luminosity of $10^{35}~\mathrm{cm}{}^{-2}\mathrm{s}{}^{-1}$. The method is discussed in the context of the weak mixing angle measurement in the same experiment., Comment: 30 pages, 9 figures. Some typos found in the published version are corrected here

We studied the $ep\rightarrow ep+2jets$ diffractive cross section with ZEUS phase space. Neglecting the $t$-channel momentum in the Born and gluon dipole impact factors, we calculated the corresponding contributions to the cross section differential in $\beta=\frac{Q^{2}}{Q^{2}+M_{2jets}^{2}}$ and the angle $\phi$ between the leptonic and hadronic planes. The gluon dipole contribution was obtained in the exclusive $k_{t}$-algorithm with the exclusive cut $y_{cut}=0.15$ in the small $y_{cut}$ approximation. In the collinear approximation we canceled singularities between real and virtual contributions to the $q\bar{q}$ dipole configuration, keeping the exact $y_{cut}$ dependency. We used the Golec-Biernat - W\"usthoff (GBW) parametrization for the dipole matrix element and linearized the double dipole contributions. The results give roughly $\frac{1}{2}$ of the observed cross section for small $\beta$ and coincides with it for large $\beta.$, Comment: 40 pages, 7 figures

We present two NLO exclusive impact factors computed in the QCD shock wave approach. These are the very first steps towards precision studies of a wide range of high energy exclusive processes with saturation effects in $ep$, $eA$, $pp$ and $pA$ collisions., Comment: 8 pages, 2 figures, to appear in the proceedings of XXV International Workshop on Deep-Inelastic Scattering and Related Subject - DIS 2017, 3-7 April 2017, University of Birmingham, UK

We perform the first next-to-leading order computation of the $\gamma^{(*)} \to V$ ($\rho, \phi, \omega$) impact factor in the QCD shockwave approach and in the most general kinematics. This paves the way to the very first quantitative study of high-energy nucleon and nucleus saturation beyond the leading order, in various processes to be measured in $ep$, $eA$, $pp$ and $pA$ collisions at existing and future colliders., Comment: 7 pages, 1 figure

Relying on the shockwave approach, we present the main steps of the computation of the impact factor for the exclusive diffractive photo- or electro- production of a forward dijet with NLO accuracy. We provide details of the cancellation mechanisms for all the divergences which appear in the intermediate results., Comment: 4 pages, 1 figure; proceedings of "Diffraction 2016", International Workshop on Diffraction in High-Energy Physics, Acireale (Catania, Sicily), Sept. 2-8, 2016; to be published in the conference proceedings by AIP

We present the calculation of the impact factor for the $\gamma^{(*)}\to q\bar{q}$ transition with one loop accuracy in arbitrary kinematics. The calculation was done within Balitsky's high energy operator expansion. Together with our previous result for the $\gamma^{(*)}\to q\bar{q} g$ Born impact factor it allows one to derive cross-sections for 2- (one loop) and 3-jet (Born) difractive electroproduction. We write such cross sections for the 2 and 3 jet exclusive diffractive electroproduction off a proton in terms of hadronic matrix elements of Wilson lines. For the 2-jet cross section we demonstrate the cancellation of IR, collinear and rapidity singularities. Our result can be directly exploited to describe the recently analyzed data on exclusive dijet production at HERA and used for the study of jet photoproduction in ultraperipheral proton or nuclear scattering., Comment: 54 pages, 2 figures

The NLO evolution equations for quadrupole and double dipole operators have been obtained within the high energy operator expansion method. The corresponding quasi-conformal evolution equations for the composite operators were constructed.

We present the calculation of the impact factor for the photon to quark, antiquark and gluon transition within Balitsky's shock-wave formalism. We also rederive the impact factor for photon to quark and antiquark transition. These results provide the necessary building blocks for further phenomenological studies of inclusive diffractive deep inelastic scattering as well as for two and three jets diffractive production which go beyond approximations discussed in the literature., Comment: 4 pages, 1 figure, to appear in the proceedings of Diffraction 2014, September 10-16, 2014, Primo\v{s}ten, Croatia

In view of future phenomenological applications, we study the impact factor for the photon to quark, antiquark and gluon transition within Balitsky's shock-wave formalism. The aim of the present program is to extend existing results beyond approximations discussed in the literature. We present our results of the real contribution, and report on recent progress in calculating the virtual contributions for the photon to quark, antiquark transition., Comment: 10 pages, 6 figures; proceedings of PHOTON 2015: International Conference on the Structure and the Interactions of the Photon, Novosibirsk, Russia, 15 - 19 June, 2015

We study the impact factor for the photon to quark, antiquark and gluon transition within Balitsky's shock-wave formalism. Our aim is to extend existing results beyond approximations discussed in the literature. We present our results of the real contribution, and present some intermediate results on virtual contributions for the photon to quark, antiquark transition., Comment: 11 pages, 5 figures, proceedings of 2015 EDS Blois, Borgo, Corsica, France. arXiv admin note: substantial text overlap with arXiv:1511.02785, arXiv:1503.01782

The NLO evolution equations for quadrupole and double dipole operators have been obtained within the high energy operator expansion method. The corresponding quasi-conformal evolution equations for the composite operators were constructed.

We present the calculation of the impact factor for the photon to quark, antiquark and gluon transition within Balitsky's shock-wave formalism. We also rederive the impact factor for photon to quark and antiquark transition. These results provide the necessary building blocks for further phenomenological studies of inclusive diffractive deep inelastic scattering as well as for two and three jets diffractive production which go beyond approximations discussed in the literature., Comment: 4 pages, 1 figure, to appear in the proceedings of Diffraction 2014, September 10-16, 2014, Primo\v{s}ten, Croatia

It is well known that high-energy scattering of a meson from some hadronic target can be described by the interaction of that target with a color dipole formed by two Wilson lines corresponding to fast quark-antiquark pair. Moreover, the energy dependence of the scattering amplitude is governed by the evolution equation of this color dipole with respect to rapidity. Similarly, the energy dependence of scattering of a baryon can be described in terms of evolution of a three-Wilson-lines operator with respect to the rapidity of the Wilson lines. We calculate the evolution of the 3-quark Wilson loop operator in the next-to-leading order (NLO) and present a quasi-conformal evolution equation for a composite 3-Wilson-lines operator. We also obtain the linearized version of that evolution equation describing the amplitude of the odderon exchange at high energies.

We present the calculation of the impact factor for the gamma(*) -> q qb g transition within Balitsky's high energy operator expansion. We also rederive the impact factor for the gamma(*) -> q qb transition within the same framework. These results provide the necessary building blocks for further phenomenological studies of inclusive diffractive deep inelastic scattering as well as for two and three jets diffractive production which go beyond approximations discussed in the litterature., Comment: 27 pages, 2 figures

We present the calculation of the impact factor for the gamma(*) -> q qb g transition within Balitsky's high energy operator expansion. We also rederive the impact factor for the gamma(*) -> q qb transition within the same framework. These results provide the necessary building blocks for further phenomenological studies of inclusive diffractive deep inelastic scattering as well as for two and three jets diffractive production which go beyond approximations discussed in the litterature., Comment: 27 pages, 2 figures

It is well known that high-energy scattering of a meson from some hadronic target can be described by the interaction of that target with a color dipole formed by two Wilson lines corresponding to fast quark-antiquark pair. Moreover, the energy dependence of the scattering amplitude is governed by the evolution equation of this color dipole with respect to rapidity. Similarly, the energy dependence of scattering of a baryon can be described in terms of evolution of a three-Wilson-lines operator with respect to the rapidity of the Wilson lines. We calculate the evolution of the 3-quark Wilson loop operator in the next-to-leading order (NLO) and present a quasi-conformal evolution equation for a composite 3-Wilson-lines operator. We also obtain the linearized version of that evolution equation describing the amplitude of the odderon exchange at high energies.

It is demonstrated that the NLO forward BFKL equation can be solved in the space of its Born eigenfunctions., Comment: 6 pages

It is demonstrated that the NLO forward BFKL equation can be solved in the space of its Born eigenfunctions., Comment: 6 pages

The connected contribution to the kernel of the evolution equation for the 3-quark Wilson loop operator was derived within Balitsky high energy operator expansion. Its C-odd part was linearized and transferred to the momentum space., Comment: 25 pages, 3 figures

The connected contribution to the kernel of the evolution equation for the 3-quark Wilson loop operator was derived within Balitsky high energy operator expansion. Its C-odd part was linearized and transferred to the momentum space., Comment: 25 pages, 3 figures

It is demonstrated that the NLO forward BFKL equation can be solved in the space of its Born eigenfunctions., Comment: 6 pages

The evolution equation for the 3 quark Wilson loop operator has been derived in the leading logarithm approximation within Balitsky high energy operator expansion., Comment: 10 pages

The evolution equation for the 3 quark Wilson loop operator has been derived in the leading logarithm approximation within Balitsky high energy operator expansion., Comment: 10 pages

We study the connection between complete representations of gauge invariant operators and their Moebius representations acting in a limited space of functions. The possibility to restore the complete representations from Moebius forms in the coordinate space is proven and a method of restoration is worked out. The operators for transition from the standard BFKL kernel to the quasi-conformal one are found both in Moebius and total representations., Comment: Changed title and a short paragraph in the section "Conclusion"; unchanged results. Version to appear on Nucl. Phys. B

We study the connection between complete representations of gauge invariant operators and their Moebius representations acting in a limited space of functions. The possibility to restore the complete representations from Moebius forms in the coordinate space is proven and a method of restoration is worked out. The operators for transition from the standard BFKL kernel to the quasi-conformal one are found both in Moebius and total representations., Comment: Changed title and a short paragraph in the section "Conclusion"; unchanged results. Version to appear on Nucl. Phys. B

We study the connection between complete representations of gauge invariant operators and their Moebius representations acting in a limited space of functions. The possibility to restore the complete representations from Moebius forms in the coordinate space is proven and a method of restoration is worked out. The operators for transition from the standard BFKL kernel to the quasi-conformal one are found both in Moebius and total representations., Comment: Changed title and a short paragraph in the section "Conclusion"; unchanged results. Version to appear on Nucl. Phys. B

We demonstrate that the ambiguity of the low-x evolution kernels in the next-to-leading order (NLO) permits one to match the Mobius form of the BFKL kernel and the kernel of the colour dipole model and to construct the Mobius invariant NLO BFKL kernel in N=4 supersymmetric Yang-Mills theory., Comment: 17 pages, references added

It is shown that in the case of the forward scattering the most part of the difference between the M\"obius form of the BFKL kernel and the BK kernel in the next-to-leading order (NLO) can be eliminated by the transformation related to the choice of the energy scale in the representation of scattering amplitudes. Change of the nonforward BFKL kernel under this transformation is derived as well. The functional identity of the forward BFKL kernel in the momentum and M\"obius representations in the leading order (LO) is exhibited and its NLO validity in N=4 supersymmetric Yang-Mills theory is proved., Comment: 38 pages

Observations of the light curve for the 3.7-day Cepheid RT Aur both before and since 1980 indicate that the variable is undergoing an overall period increase, amounting to +0.082 +-0.012 s/yr, rather than a period decrease, as implied by all observations prior to 1980. Superposed on the star's O-C variations is a sinusoidal trend that cannot be attributed to random fluctuations in pulsation period. Rather, it appears to arise from light travel time effects in a binary system. The derived orbital period for the system is P = 26,429 +-89 days (72.36 +-0.24 years). The inferred orbital parameters from the O-C residuals differ from those indicated by existing radial velocity data. The latter imply the most reasonable results, namely a1 sin i = 9.09 (+-1.81) x 10^8 km and a minimum secondary mass of M2 = 1.15 +-0.25 Msun. Continued monitoring of the brightness and radial velocity changes in the Cepheid are necessary to confirm the long-term trend and to provide data for a proper spectroscopic solution to the orbit., Comment: Accepted for publication in PASP (November 2007)

This paper is devoted to the calculation of the Reggeized quark-Reggeized quark-gluon effective vertex in perturbative QCD in the next-to-leading order. The case of QCD with massless quarks is considered and the correction is obtained in the D->4 limit. This vertex appears in the quark Reggeization theory, which next-to-leading order extension is now under construction., Comment: 20 pages, 3 figures, elsart documetclass

Observations of the light curve for the 3.7-day Cepheid RT Aur both before and since 1980 indicate that the variable is undergoing an overall period increase, amounting to +0.082 +-0.012 s/yr, rather than a period decrease, as implied by all observations prior to 1980. Superposed on the star's O-C variations is a sinusoidal trend that cannot be attributed to random fluctuations in pulsation period. Rather, it appears to arise from light travel time effects in a binary system. The derived orbital period for the system is P = 26,429 +-89 days (72.36 +-0.24 years). The inferred orbital parameters from the O-C residuals differ from those indicated by existing radial velocity data. The latter imply the most reasonable results, namely a1 sin i = 9.09 (+-1.81) x 10^8 km and a minimum secondary mass of M2 = 1.15 +-0.25 Msun. Continued monitoring of the brightness and radial velocity changes in the Cepheid are necessary to confirm the long-term trend and to provide data for a proper spectroscopic solution to the orbit., Comment: Accepted for publication in PASP (November 2007)

The dipole form of the gluon part of the colour singlet BFKL kernel in the next-to-leading order (NLO) is obtained in the coordinate representation by direct transfer from the momentum representation, where the kernel was calculated before. With this paper the transformation of the NLO BFKL kernel to the dipole form, started a few months ago with the quark part of the kernel, is completed., Comment: 26 pages

This paper is devoted to the calculation of the Reggeized quark-Reggeized quark-gluon effective vertex in perturbative QCD in the next-to-leading order. The case of QCD with massless quarks is considered and the correction is obtained in the D->4 limit. This vertex appears in the quark Reggeization theory, which next-to-leading order extension is now under construction., Comment: 20 pages, 3 figures, elsart documetclass

Observations of the light curve for the 3.7-day Cepheid RT Aur both before and since 1980 indicate that the variable is undergoing an overall period increase, amounting to +0.082 +-0.012 s/yr, rather than a period decrease, as implied by all observations prior to 1980. Superposed on the star's O-C variations is a sinusoidal trend that cannot be attributed to random fluctuations in pulsation period. Rather, it appears to arise from light travel time effects in a binary system. The derived orbital period for the system is P = 26,429 +-89 days (72.36 +-0.24 years). The inferred orbital parameters from the O-C residuals differ from those indicated by existing radial velocity data. The latter imply the most reasonable results, namely a1 sin i = 9.09 (+-1.81) x 10^8 km and a minimum secondary mass of M2 = 1.15 +-0.25 Msun. Continued monitoring of the brightness and radial velocity changes in the Cepheid are necessary to confirm the long-term trend and to provide data for a proper spectroscopic solution to the orbit., Comment: Accepted for publication in PASP (November 2007)

The compatibility of the multi--Regge form of QCD amplitudes in the quasi--multi--Regge kinematics (QMRK) and the s--channel unitarity imposes some constraints on the effective jet--production vertices. We demonstrate that these constraints known as bootstrap conditions are satisfied for the amplitudes with the Reggeized quark exchanges., Comment: 25 pages, 1 figure, uses elsart.cls

The compatibility of the multi--Regge form of QCD amplitudes in the quasi--multi--Regge kinematics (QMRK) and the s--channel unitarity imposes some constraints on the effective jet--production vertices. We demonstrate that these constraints known as bootstrap conditions are satisfied for the amplitudes with the Reggeized quark exchanges., Comment: 25 pages, 1 figure, uses elsart.cls