On the calculation of the NLO virtual photon impact factor

Fadin, V. S.; Ivanov, Dmitry Yu.; Kotsky, M.I.

doi:10.1016/s0550-3213(03)00219-0

Cited by 42 publications

(34 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This would involve knowledge of the NLL BFKL kernel with heavy quarks included in the fermionic contributions, and this is not available. One can only neglect the term involving A gg and hope that that it is not significant 15 . We thus define the (approximate) NLL variable flavour coefficient to be:…”

Section: Treatment Of Heavy Flavoursmentioning

confidence: 99%

A Global Fit to Scattering Data with NLL BFKL Resummations

White¹,

Thorne²

2007

15th International Workshop on Deep-Inelastic Scattering and Related Subjects DIS 2007

View full text Add to dashboard Cite

We calculate DIS-scheme splitting and coefficient functions for electromagnetic deep inelastic scattering with small x resummations, as given by the NLL BFKL equation with running coupling and approximate NLL resummed impact factors. The resummations are combined with a NLO fixed order expansion, and the improved quantities thus obtained are stable at small x and significantly suppressed with respect to LL results. These results are implemented in a global fit to DIS and related data, and the results compared to a NLO fixed order DIS-scheme fit and with a previous LL resummed fit. The NLL resummed fit quality is excellent, and constitutes a marked improvement over the purely fixed order approach. The input gluon, at Q 2 0 = 1 GeV 2 , obtained from the resummed fit is positive and slightly increasing as x → 0, in contrast to the result obtained at fixed order. A resummed prediction for the longitudinal structure function FL is presented. It is positive definite and growing with energy at low x and Q 2 , where the fixed order results show a significant perturbative instability.

show abstract

Section: Treatment Of Heavy Flavoursmentioning

confidence: 99%

A Global Fit to Scattering Data with NLL BFKL Resummations

White¹,

Thorne²

2007

15th International Workshop on Deep-Inelastic Scattering and Related Subjects DIS 2007

View full text Add to dashboard Cite

show abstract

“…While its LO expression is known since long, the NLO calculation, carried out in the momentum representation, turned out to be rather complicated and was completed only after year-long efforts [38][39][40][41][42][43][44]. The lengthy result was published over a few years in pieces, some of them available only in the form of a numerical code, thus making it of limited practical use.…”

Section: Jhep10(2014)058mentioning

confidence: 99%

“…It would be interesting to understand the reason for the practically complete cancellation of the subleading 1/N 2 c terms which takes place here. Finally, we want to compare the results for the photon impact factor which we used in this paper (derived from the results in [49,50]) with the ones obtained in the conventional BFKL approach by Bartels and collaborators [38][39][40][41][42][43][44]. Unfortunately, some information (in numerical form) about the final result for the impact factor is available only for the case of transverse polarization -see ref.…”

Section: Jhep10(2014)058mentioning

confidence: 99%

The γ * γ * total cross section in next-to-leading order BFKL and LEP2 data

Ivanov

Murdaca

Papa

2014

J. High Energ. Phys.

View full text Add to dashboard Cite

We study the total cross section for the collision of two highly-virtual photons at large energies, taking into account the BFKL resummation of energy logarithms with full next-to-leading accuracy. A necessary ingredient of the calculation, the next-to-leading order impact factor for the photon to photon transition, has been calculated by Balitsky and Chirilli using an approach based on the operator expansion in Wilson lines. We extracted the result for the photon impact factor in the original BFKL calculation scheme comparing the expression for the photon-photon total cross section obtained in BFKL with the one recently derived by Chirilli and Kovchegov in the Wilson-line operator expansion scheme.We perform a detailed numerical analysis, combining different, but equivalent in nextto-leading accuracy, representations of the cross section with various optimization methods of the perturbative series. We compare our results with previous determinations in the literature and with the LEP2 experimental data. We find that the account of Balitsky and Chirilli expression for the photon impact factor reduces the BFKL contribution to the cross section to very small values, making it impossible to describe LEP2 data as the sum of BFKL and leading-order QED quark box contributions.

show abstract

“…While the nearly decade long efforts have culminated in the derivation [264] of the NLO BFKL evolution kernel, the matching calculations of the effect of hard gluons in the NLO impact factors are missing. In the case of DIS those hard gluons are of perturbative origin, but even so, despite the great progress [265,266], the closed result for the impact factor of the virtual photon is not available yet. In the case of vector mesons, the evaluation of the NLO impact factor can not be separated from the issue of the higher, nonperturbative, qqg, Fock state of the vector meson, in which the gluon carries a finite fraction of the vector meson's momentum.…”

Section: Beyond the Leading Log 1 X Approximationmentioning

confidence: 99%