1 Erratum to: Eur. Phys. J. C (2015) 75:566 DOI 10.1140/epjc/s10052-015-3780-3

In the original publication of the article unfortunately a part of the acknowledgments was omitted.

Please find the missing acknowledgment here:

This project is financed in part from funds of the Polish National Science Centre under decision DEC-2011/03/B/ST2/00107.