Investigations into the BFKL mechanism with a running QCD coupling
(1998) In Physical Review D (Particles and Fields) 57(9). p.55435554 Abstract
 We present approximations of varying degree of sophistication to the integral equations for the (gluon) structure functions of a hadron ("the partonic flux factor") in a model valid in the leading log approximation with a running coupling constant. The results are all of the BFKL type, i.e., a power in the Bjorken variable x(B)(lambda) with the parameter lambda determined from the size alpha(0) of the "effective" running coupling <(alpha)over bar>=3 alpha(s)/pi =alpha(0)/ln(k(perpendicular to)(2)) and varying depending upon the treatment of the transverse momentum pole, we also consider the implications for the transverse momentum (k(perpendicular to)) fluctuations along the emission chains and we obtain an exponential falloff in... (More)
 We present approximations of varying degree of sophistication to the integral equations for the (gluon) structure functions of a hadron ("the partonic flux factor") in a model valid in the leading log approximation with a running coupling constant. The results are all of the BFKL type, i.e., a power in the Bjorken variable x(B)(lambda) with the parameter lambda determined from the size alpha(0) of the "effective" running coupling <(alpha)over bar>=3 alpha(s)/pi =alpha(0)/ln(k(perpendicular to)(2)) and varying depending upon the treatment of the transverse momentum pole, we also consider the implications for the transverse momentum (k(perpendicular to)) fluctuations along the emission chains and we obtain an exponential falloff in the relevant kappa=ln(k(perpendicular to)(2)) variable, i.e., an inverse power (k(perpendicular to)(2))((2+lambda)) with the same parameter lambda. This is different from the BFKL result for a fixed coupling, where the distributions are Gaussian in the kappa variable with a width as in a Brownian motion determined by "the length" of the emission chains, i.e., In(1/x(B)). The results are verified by a realistic Monte Carlo simulation and we provide a simple physics motivation for the change. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/record/33704
 author
 Andersson, Bo ^{LU} ; Gustafson, Gösta ^{LU} and Kharraziha, Hamid
 organization
 publishing date
 1998
 type
 Contribution to journal
 publication status
 published
 subject
 in
 Physical Review D (Particles and Fields)
 volume
 57
 issue
 9
 pages
 5543  5554
 publisher
 American Physical Society
 external identifiers

 scopus:0001663240
 ISSN
 05562821
 DOI
 10.1103/PhysRevD.57.5543
 language
 English
 LU publication?
 yes
 id
 561f60489d7345d9bf432d36ca2c7ac1 (old id 33704)
 alternative location
 http://link.aps.org/abstract/PRD/v57/p5543
 date added to LUP
 20080114 14:51:35
 date last changed
 20180107 08:46:02
@article{561f60489d7345d9bf432d36ca2c7ac1, abstract = {We present approximations of varying degree of sophistication to the integral equations for the (gluon) structure functions of a hadron ("the partonic flux factor") in a model valid in the leading log approximation with a running coupling constant. The results are all of the BFKL type, i.e., a power in the Bjorken variable x(B)(lambda) with the parameter lambda determined from the size alpha(0) of the "effective" running coupling <(alpha)over bar>=3 alpha(s)/pi =alpha(0)/ln(k(perpendicular to)(2)) and varying depending upon the treatment of the transverse momentum pole, we also consider the implications for the transverse momentum (k(perpendicular to)) fluctuations along the emission chains and we obtain an exponential falloff in the relevant kappa=ln(k(perpendicular to)(2)) variable, i.e., an inverse power (k(perpendicular to)(2))((2+lambda)) with the same parameter lambda. This is different from the BFKL result for a fixed coupling, where the distributions are Gaussian in the kappa variable with a width as in a Brownian motion determined by "the length" of the emission chains, i.e., In(1/x(B)). The results are verified by a realistic Monte Carlo simulation and we provide a simple physics motivation for the change.}, author = {Andersson, Bo and Gustafson, Gösta and Kharraziha, Hamid}, issn = {05562821}, language = {eng}, number = {9}, pages = {55435554}, publisher = {American Physical Society}, series = {Physical Review D (Particles and Fields)}, title = {Investigations into the BFKL mechanism with a running QCD coupling}, url = {http://dx.doi.org/10.1103/PhysRevD.57.5543}, volume = {57}, year = {1998}, }