A new phenomenological investigation of KMR and MRW unintegrated parton distribution functions

Abstract

We address the longitudinal proton structure function, F L (x, Q 2 ), from the k t -factorization formalism by using the unintegrated parton distribution functions (UPDF) which are generated through the KMR and MRW procedures. The LO UPDF of the KMR prescription is extracted, by taking into account the PDF of Martin et al, i.e., MSTW2008-LO and MRST99-NLO, and next the NLO UPDF of the MRW scheme is generated through the set of MSTW2008-NLO PDF as the input. The different aspects of F L (x, Q 2 ) in the two approaches, as well as its perturbative and nonperturbative parts, are calculated. Then the comparison of F L (x, Q 2 ) is made with the data given by the ZEUS and H1 collaborations. It is demonstrated that the extracted F L (x, Q 2 ), based on the UPDF of two schemes, are consistent with the experimental data, and to a good approximation they are independent of the input PDF. But the one developed from the KMR prescription has better agreement with the data with respect to that of MRW. As has been suggested, by lowering the factorization scale or the Bjorken variable in the related experiments it may be possible to analyze the present theoretical approaches more accurately.

NLO production of W± and Z0 vector bosons via hadron collisions in the frameworks of Kimber-Martin-Ryskin and Martin-Ryskin-Watt unintegrated parton distribution fu

“…Consequently, the overall value of the differential cross-sections of the W ± and Z 0 production in this framework reduces dramatically, as it is apparent in the figures 7 and 8 . In overall and as it has been stated elsewhere (see for example the references [27,28]) the results in the KM R scheme seemingly have a better agreement with the experiment. This is to some extend ironic, since the LO and the N LO M RW formalisms are developed as extensions and improvements to the KM R approach and are more compatible with the DGLAP evolution equation.…”

A validity check of the KATIE parton level event generator in the $k_t$-factorization and collinear frameworks

“…As it can be seen in this figure, the result of the k t -factorization with the LO-MRW and NLO-MRW UPDFs are strangely off the data. Because, in the previous works, It was shown that the MRW UPDFs can produce the corresponding data reasonably [26][27][28][29][30][31][32][33][34], so to be sure what makes our calculation to get worse, we evaluated the differential cross section within the collinear factorization framework, using the MMHT2014nlo68cl PDFs. The prediction of the collinear factorization, as depicted in the left panel of figure 1, convinces us that there should be something wrong with this parton level event generator [3].…”

“…Another approach for defining UPDFs is the Martin-Ryskin-Watt (MRW) approach [17,18] which assumes parton evolves according to the DGLAP evolution equations [12][13][14] till the last parton emission, and then it resums the no-emission parton probability to the hard factorization scale via the Sudakov form factor. This method is investigated in detail [19][20][21][22][23][24][25] and is shown to be successful in describing the data of different processes at the LHC, Tevatron etc [26][27][28][29][30][31][32][33][34].…”

A detailed study of charm content of a proton in the frameworks of the Kimber-Martin-Ryskin and Martin-Ryskin-Watt approaches

“…In our previous articles, we investigated the general behavior and stability of the KM R and M RW schemes [19][20][21][22][23][24][25][26][27]. Also, we have successfully used KM R-U P DF to calculate the inclusive production of the W and Z gauge vector bosons [28,29], the semi-N LO production of Higgs bosons [30], the production of forward-center and forward-forward di-jets [31], the prompt-photon pair production [32] and recently in the reference [33], we explored the phenomenology of the integral and the differential versions of the KM R-U P DF using the angular (strong) ordering (AOC (SOC)) constraints.…”