arXiv subjects

Marcello Ciafaloni

Publications and source records attributed to Marcello Ciafaloni.

25 records · Page 2Linked to original sources

arXiv1998

Energy Scale(s) and Next-to-leading BFKL Equation

We complete the calculation of the next-to-leading kernel of the BFKL equation, by disentangling its energy-scale dependent part from the impact factor corrections in large-k dijet production. Using the irreducible part previously obtained,we derive the final form of the kernel eigenvalue and of the hard Pomeron shift for various scales. We also discuss the scale changes,the physical equivalence of a class of scales, and how to use collinear safe ones.

hep-ph↗

arXiv1998

Energy Scale and Coherence Effects in small-x Equations

I consider the next-to-leading,high-energy cluster expansion of large-k double-jet production in QCD, and I determine the corresponding one-loop quark and gluon impact factors, for a self-consistent energy scale. The result shows that coherent angular ordering of emitted gluons holds for hard emission also, and singles out a scale which is essentially the largest virtuality in the process. Both remarks are relevant for the precise deter- mination of the BFKL kernel at the next-to-leading level.

hep-ph↗

arXiv1997

k-Factorization and Next-to-leading BFKL Kernel

I review recent results by Fadin,Lipatov and collaborators and by our group,leading to the almost complete calculation of the next-to-leading BFKL kernel,of its eigenvalues,and of the resummed gluon anomalous dimension. Qualitative implications for small-x structure functions include consistent running coupling effects and a sizeable decrease of the Pomeron intercept,so as to slow down the small-x rise at low values of Q.

hep-ph↗

arXiv1996

Higher Topologies in 2+1-Gravity

I argue that the first-order formalism recently found to describe classical 2+1-Gravity with matter, is also able to include higher topologies. The present gauge, which is conformal with vanishing York time, is characterized by an analytic mapping from single-valued coordinates to Minkowskian ones. In the torus case, this mapping is based on four square-root branch points, whose location is related to the modulus, which has a well defined time dependence. In the general case, it is connected with the hyperelliptic representation of Riemann surfaces.

hep-th↗

arXiv1995

k-Factorization

I review the k-factorization method to combine the high-energy behaviour in QCD with the renormalization group. Resummation formulas for coefficient functions and anomalous dimensions are derived, and their applications to small-x scaling violations in structure functions are briefly discussed.

hep-th↗

arXiv1995

Kt-Factorization vs. Renormalization Group: A small-x Consistency Argument

The consistency of the BFKL equation with the renormalization group is investigated at next-to-leading log-x level.By use of Kt-factorization, it is found that,besides next-to-leading small-x resummation formulae, a leading, x-dependent redefinition of initial quarks and gluons is needed. Its interpretation and phenomenological relevance are discussed.

hep-ph↗

arXiv1991

Classical Scattering in 2+1 Gravity with N Spinning Sources

The classical dynamics of N spinning point sources in 2+1 Einstein-Cartan gravity is considered. It corresponds to the ISO(2,1) Chern-Simons theory, in which the torsion source is restricted to its intrinsic spin part. A class of explicit solutions is found for the dreibein and the spin connection, which are torsionless in the spinless limit. By using the residual local Poincare' invariance of the solutions, we fix the gauge so that the metric is smooth outside the particles and satisfies proper asymptotic conditions at space and time infinity. We recover previous results for test bodies and find new ones for the scattering of two dynamical particles in the massless limit.

hep-th↗