arXiv subjects
Publications and source records attributed to Mrinal Dasgupta.
We calculate the resummed distributions for the thrust in DIS in the limit T->1. Two variants of the thrust are considered: that normalised to Q/2, and that normalised to the energy in the current hemisphere. The results expanded to second order are compared to predictions from the Monte Carlo programs DISENT and DISASTER++. A prescription is given for matching the resummed expressions with the full fixed order calculation.
We provide an exact analytical calculation at the two-loop level in the abelian limit of the leading power correction for the C parameter in e+e- annihilation. We compare our results to the numerical value obtained employing the soft approximation, the abelian part of the Milan factor. We demonstrate that a simple proportionality holds between the leading power corrections to the C parameter and to the longitudinal cross section in the soft region, and we verify that this proportionality holds for the full two-loop abelian contribution computed here. We comment on the possibility of extending this technique to other event shape variables and distributions, as well as to the non-abelian contributions.
We estimate the power corrections (infrared renormalon contributions) to the coefficient functions for the differential Drell-Yan cross-section $d^2σ/dQ^2dy$, where $Q^2$ is the mass squared and $y$ the rapidity of the produced lepton pair. We employ the dispersive method based on the analysis of one-loop Feynman graphs containing a massive gluon.
This talk discusses the power behaved corrections to fragmentation functions for the current jet in non-singlet deep inelastic scattering. These corrections are estimated by means of a renormalon model using a dispersive approach. The assumption of a universal infrared finite coupling enables us to provide quantitative estimates.
Results are presented for the leading power-suppressed (1/Q) contributions to shape variables in deep inelastic lepton scattering. These are then combined with available leading order perturbative estimates.