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Double-diffractive production of heavy quarkonia. Roman Pasechnik. Dubna, JINR. based on: R. Pas echnik, A. Szczurek, O. Teryaev Phys. Rev. D78: 014007, 2008. Inclusive heavy quarkonia production. agreement with the data. NLLA BFKL vertex in QMRK. kt-factorization approach. - PowerPoint PPT Presentation
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Double-diffractive production Double-diffractive production of heavy quarkoniaof heavy quarkonia
Dubna, JINR
Roman Pasechnik
Inclusive heavy quarkonia production
kt-factorizationapproach
NLLA BFKL vertexin QMRK
agreement with the data
P. Hagler, R. Kirshner, A. Schafer, L. Szymanowski, O. Teryaev, ‘00,’01A. Lipatov, V. Saleev, N. Zotov, ‘01, ‘03
Kaidalov-Khose-Martin-Ryskin (KKMR) approach
Exclusive diffractive Higgs production in terms of UGDFs
Our goal:
• to apply this QCD mechanism to heavy quarkonia production• to explore related uncertainties
production vertex
pNRQCD projector to color singlet bound state
gluon virtualities are explicitly taken into account !
satisfied! projection to gluon polarizations
KMR UGDF
Sudakov f.fintegrated
density
main contribution to the amplitude comes fromvery small gluon transverse momenta
huge sensitivity to details in non-perturbative domain !!!
hard scale
different prescriptions for
Major uncertainties in KMR approachDependence on effective transverse momentum in KMR approach
Dependence on the lower cut on the gluon transverse momenta Off-shell effect Different models for
the running coupling
Our results for different UGDFs
xF-distribution for Gaussian UGDF
different scale choices
Transverse meson momentumdistribution for different UGDFs
KMR UGDF
Our results for different UGDFst,xF,y-distributions for different UGDFs:KL – dashed; GBW – dotted; BFKL – dash-dotted; KMR – solid (in min, max eff Qt-prescriptions)
Off-shell effect at different rapidities and meson masses
Main points and results1. Strong dependence on factorization scale choice, especially
3. We don’t use KMR UGDF based on Sudakov because of very restricted region of gluon momentum fractions allowed by Sudakov formfactor. We would need in extrapolation to other regions that is mainly arbitrary.
5. Significant contribution to cross section comes from non-perturbative region (order of fraction of GeV), unlike Higgs production – a sort of continuation of perturbative result to the region where its applicability cannot be rigorously proven.
2. Strong dependence on UGDFs choice. We use non-perturbativelymodelled UGDFs, like KL, Gauss etc. Experiments should justify whatUGDF is valid.
4. Off-shellness of the intermediate gluons is estimated to be important in the case of charmonium production.