1. Tomasz Stebel (with Leszek Motyka and Mariusz Sadzikowski) M. Smoluchowski Institute of Physics, Jagiellonian University

2. 2

3. 3 ATLAS, arXiv:1606.00689

4. 4 Phys. Rev. D 21 (1980) 2712 It is valid up to NLO, at the leading twist. Checked for the DY dipole model approach Motyka, Sadzikowski, TS, JHEP 1505 (2015) 087 NNLO corrections L-T rel. breaking Mirkes and Ohnemus, Phys. Rev. D 51, 4891 (1995). Boer, Phys. Rev. D 60, 014012 (1999) Boer and Mulders, Phys. Rev. D 57, 5780 (1998) Peng, Chang, McClellan, Teryaev, Phys.Lett. B758 (2016) 384-388

5. Recent ATLAS analysis for 8 TeV 5 JHEP 1608 (2016) 159, arXiv:1606.00689

6. Parton shower: 6

7. 7 Gribov Balitsky, Fadin, Kuraev, Lipatov, Levin, Ryskin Catani, Ciafaloni, Collins, Ellis kT approach in DY: Brodsky, Habecker, Quack Kopeliovich Nefedov, Nikolaev, Saleev Baranov, Lipatov, Zotov

8. Following: Nefedov, Nikolaev, Saleev; Phys.Rev. D87 (2013) no.1, 014022; arXiv:1211.5539. 8 Quark Parton Reggeization Approach Gluon Transverse- momentum-dependent distribution (TDM) Hautmann, Hentschinski, Jung, arXiv:1207.6420

9. 9 Gluon TDM: Jung, Hautmann, arXiv:1312.7875

10. Two channels: 2 diagrams Approximate NNLO = no gluon emission included Brodsky, Arthur Hebecker, E. Quack; Phys.Rev. D55 (1997) 2584-2590 Schäfer, Szczurek, Phys.Rev. D93 (2016) no.7, 074014 8 diagrams NEW 10

11.  Jung, Hautmann (JH)  LO BFKL solution for TMD (with GBW initial condition): 11 arXiv:1207.6420 Mellin tr.  Weisacker–Williams-type gluon:

12. 12

13. 13 WWJH BFKL

14. 14

15. 15

16.  ATLAS data for 7 TeV, small dilepton mass (photon mediated). 16 arXiv:1404.1212 Martin, Ryskin, Watt, Phys. Rev. D 70, 014012 (2004); Lipatov, Malyshev, Zotov, JHEP 1112, 117 (2011).

17. 15