| 1. |
- Krelina, M., et al.
(author)
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The onset of spin rotation effects in electroproduction of heavy quarkonia
- 2019
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In: European Physical Society Conference on High Energy Physics (EPS-HEP2019). - Trieste, Italy : Sissa Medialab. - 1824-8039. ; 364
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Conference paper (peer-reviewed)abstract
- We discuss the Melosh spin rotation effects in diffractive photo- and electroproduction of heavy quarkonia off a nucleon target in the dipole picture. The quarkonium light-front wave functions are obtained in the Schroedinger equation based formalism using the realistic interquark interaction potentials. A strong onset of spin rotation effects predicted in the case of J/ψ(1S) photoproduction enables us to reach a reasonable agreement with the available data. In the case of radially excited 2S and 3S states these effects are even stronger as a direct manifestation of the nodal structure of their wave functions. In particular, the spin effects enhance the Ψ0(2S) cross section by a factor of 2 − 3 and therefore cause a substantial increase of the Ψ0(2S)-to-J/Ψ(1S) ratio improving the description of experimental data.
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| 2. |
- Krelina, M., et al.
(author)
-
Nuclear effects in Drell-Yan production at the LHC
- 2016
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In: EPJ Web of Conferences. - : EDP Sciences. - 2100-014X. ; 120
-
Conference paper (peer-reviewed)abstract
- Using the color dipole formalism we study production of Drell-Yan (DY) pairs in proton-nucleus interactions in the kinematic region corresponding to LHC experiments. Lepton pairs produced in a hard scattering are not accompanied with any final state interactions leading to either energy loss or absorption. Consequently, dileptons may serve as more efficient and cleaner probes for the onset of nuclear effects than nclusive hadron production. We perform a systematic analysis of these effects in production of Drell-Yan pairs in pPb interaction at the LHC. We present predictions for the nuclear suppression as a function of the dilepton transverse momentum, rapidity and invariant mass which can be verified by the LHC measurements. We found that a strong nuclear suppression can be interpreted as an effective energy loss proportional to the initial energy universally induced by multiple initial state interactions. In addition, we study a contribution of coherent effects associated with the gluon shadowing affecting the observables predominantly at small and medium-high transverse momenta.
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| 3. |
- Krelina, M., et al.
(author)
-
Systematic study of real photon and Drell-Yan pair production in p+A (d+A) interactions
- 2016
-
In: EPJ Web of Conferences. - : EDP Sciences. - 2100-014X. ; 120
-
Conference paper (peer-reviewed)abstract
- We study nuclear effects in production of Drell-Yan pairs and direct photons in proton-nucleus collisions. For the first time, these effects are studied within the color dipole approach using the Green function formalism which naturally incorporates the color transparency and quantum coherence effects. The corresponding numerical results for the nuclear modification factor are compared with available data. Besides, we present a variety of predictions for the nuclear suppression as a function of transverse momentum pT, Feynman variable xF and invariant mass M of the lepton pair which can be verified by experiments at RHIC and LHC. We found that the nuclear suppression is caused predominantly by effects of quantum coherence (shadowing corrections) and by the effective energy loss induced by multiple initial state interactions. Whereas the former dominate at small Bjorken x2 in the target, the latter turns out to be significant at large x1 in the projectile beam and is universal at different energies and transverse momenta.
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