4,840 research outputs found
Solutions of Coupled DGLAP Evolution Equations for Singlet and Gluon Structure Functions in leading order at low-x
In this paper, we solved the coupled
Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) evolution equations for
singlet and gluon structure functions in leading order (LO) at low-x assuming
the Regge behaviour of quark and gluon structure functions at this limit, and t
and x-evolutions of singlet and gluon structure functions are presented. We
have compared our results of gluon structure function with global MRST 2004 and
GRV 1998 gluon parameterizations and the results of deuteron structure function
with New Muon Collaboration (NMC) data. We have shown that the solutions of
coupled equations give accurate results for the structure functions and also
the compatibility of Regge behaviour of quark and gluon structure functions
with perturbative quantum chromodynamics (PQCD) at low-x.Comment: 14 pages, 4 figure
The NNLO QCD analysis of gluon distribution function at small-x
A next-to-next-to-leading order (NNLO) QCD calculation of gluon distribution
function at small-x is presented. The gluon distribution function is explored
analytically in the DGLAP approach by a Taylor expansion at small x as two
first order partial differential equations in two variables : Bjorken x and t
(t = ln(Q2/{\Lambda}2) ). We have solved the system of equations at LO, NLO and
NNLO respectively by the La- granges method. The resulting analytical
expressions are compared with the available global PDF sets as well as with the
results of the BDM model. We have further performed a \c{hi}2 test to check the
com- patibility of our predictions and observed that our results can be
consistently described in the context of perturbative QCD. A comparative
analysis of the obtained results at LO, NLO and NNLO reveals that the NNLO
approximation has a significant contribution to the gluon distribution function
particularly in the small-x region.Comment: 32 pages, 23 figure
Solution of non-singlet DGLAP evolution equation in leading order and next-to-leading order at small-x by method of characteristics
The non-singlet structure functions have been obtained by solving
Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) evolution equations in
leading order (LO) and next-to-leading order (NLO) at the small-x limit. Here a
Taylor series expansion has been used and then the method of characteristics
has been applied to solve the evolution equations. Results are comopared with
the Fermilab experiment E665 data and New Muon Collaboration (NMC) data.Comment: 11 pages including 5 figure
Complete solution of Altarelli-Parisi evolution equation in next-to-leading order and non-singlet structure function at low-x
We present complete solution of Altarelli-Parisi (AP) evolution equation in
next-to-leading order (NLO) and obtain t-evolution of non-singlet structure
function at low-x. Results are compared with HERA low-x and low-Q^2 data and
also with those of complete solution in leading order (LO) of AP evolution
equation.Comment: 8 pages, 4 figure
Particular and unique solutions of DGLAP evolution equation in leading order and gluon structure function at small-x
We present particular and unique solutions of Dokshitzer- Gribov- Lipatov-
Altarelli-Parisi (DGLAP) evolution equation for gluon structure function in
leading order (LO) and obtain t and x-evolutions of gluon structure function at
small-x. The results are compared with a recent global parameterization.Comment: 16 pages, 7 figures. arXiv admin note: substantial text overlap with
arXiv:hep-ph/060504
Particular and unique solutions of DGLAP evolution equations and light sea and valence quark structure functions at low-x
We present particular and unique solutions of Dokshitzer-Gribov-Lipatov-
Altarelli-Parisi (DGLAP) evolution equations for light sea and valence quark
structure functions in leading order (LO). We obtain t evolutions of sea and
valence quark structure functions and x- evolutions of light sea quark
structure functions from DGLAP evolution equations. The results are compared
with a recent global parameterization.Comment: 17 pages, 6 figures. arXiv admin note: substantial text overlap with
arXiv:hep-ph/0605040, arXiv:1002.1589, arXiv:1002.0623, arXiv:1002.3243,
arXiv:1209.422
Gluon distribution at moderately low-x from NMC deuteron structure function data
We present some simple methods to find gluon distribution from analysis of
deuteron F_{2} structure function data at moderately low-x. Here we use the
leading order(LO) Altarelli -Parisi(AP) evolution equation and New Muon
Collaboration (NMC) deuteron F_{2} structure function data to extract gluon
distribution. We also compare our results with those of other authors.Comment: 13 pages, 5 figure
Polarized Dokshitzer-Gribov-Lipatov- Altarelli-Parisi equations and t-evolution of structure functions in next-to-leading order at small-x
In this paper the spin-dependent singlet and non-singlet structure functions
have been obtained by solving Dokshitzer-Gribov-Lipatov-Altarelli-Parisi
evolution equations in next-to-leading order in the small x limit. Here we have
used Taylor series expansion and then the particular and unique solution to
solve the evolution equations. We have also calculated t evolutions of
deuteron, proton and neutron structure functions and the results are compared
with the SLAC E-143 Collaboration data.Comment: 19 pages, 3 figure
On phenomenological study of the solution of nonlinear GLR-MQ evolution equation beyond leading order
We present a phenomenological study of the small-x behaviour of gluon
distribution function at next-to-leading order (NLO) and
next-to-next-to-leading order(NNLO) in light of the nonlinear
Gribov-Ryskin-Levin-Mueller-Qiu (GLR-MQ)evolution equation by keeping the
transverse size of the gluons () fixed. We consider the NLO and NNLO
corrections, of the gluon-gluon spitting function and strong
coupling constant . We have suggested semi-analytical solutions
based on Regge like ansatz of gluon density , which are supposed to
be valid in the moderate range of photon virtuality and at small Bjorken
variable. The study of the effects of nonlinearities that arise due to
gluon recombination effects at small-x is very interesting, which eventually
tames down the unusual growth of gluon densities towards small-x as predicted
by the linear DGLAP evolution equation.Comment: 20 pages, 10 figures, new references adde
Charge density of the electron at higher velocity
Depending on the recent experiments and some new way of explaining electron
we have developed here equations for velocities of different mode with the
charge density. This includes as well how the charge-density can be distributed
in the equatorial region with different velocities and observer-angles.Comment: 7 pages, 6 figure
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