Acknowledgments We are grateful to G. L´ opez Castro, J. Piekarewicz and S. Capstick for very useful observations. We also acknowledge the support of CONACyT, Mexico. [1] F. T. Hawes and M. A. Pichowsky, Phys. Rev. C 59 1743 (1999). [2] F. Cardarelli, et al. Phys. Lett. B 349 , 393 (1995). [3] J. P. B. C. deMelo and T. Frederico, Phys. Rev. C 55 2043 (1997). [4] Ho-Meoyng Choi and Chueng-Ryong Ji, Phys. Rev. D 70 053015 (2004) [5] M. S. Bhagwat and P. Maris, Phys. Rev. C 77 025203 (2008). [6] J. N. Hedditch, et al. Phys. Rev. D 75 094504 (2007). [7] F. X. Lee, S. Moerschbacher and W. Wilcox, Phys. Rev. D 78 094502 (2008). [8] U. Baur and D. Zeppenfeld Phys. Rev. Lett. 75 1002(1995). [9] E. N. Argyres et al. Phys Lett. B 358 339(1995). [10] M. Beuthe, R. Gonzales Felipe, G. L´ opez Castro and J. Pestieau, Nucl. Phys. B 498 55(1997). [11] G. L´ opez Castro and G. Toledo S´ anchez, Phys. Rev. D 61 033007(2000). [12] K. Hagiwara, R. D. Peccei, D. Zeppenfeld and K. Hikasa, Nucl. Phys. B 282 , 253 (1987). [13] J. F. Nieves and P. B. Pal, Phys. Rev. D 55 3118 (1997). [14] See, for example M. Napsuciale, S. Rodriguez, E. G. Delgado-Acosta and M. Kirchbach, Phys. Rev. D 77 , 014009 (2008), and references therein. [15] D. Yu. Bardin, A. Leike, T Riemann, and M. Sachwitz, Phys. Lett. B 206 , 539(1988); G. L´ opez Castro, J.L. Lucio M., and J. Pestieau, Mod. Phys. Lett. A 6 , 3679 (1991). [16] J. Gegelia and S. Scherer, arXiv:0910.4280v1 [17] B. A. Kniehl and A. Sirlin, Phys. Lett. B 530 , 129(2002), and references therein. [18] K. J. Kim and Y-S Tsai, Phys. Rev. D 7 3710(1973). [19] B. A. Arbuzov, Eur. Phys. J. C 61 , 51 (2009) [arXiv:0901.3997 [hep-ph]]. [20] J. Papavassilious, [arXiv:hep-ph/9504382]. [21] M. A. Pichowsky, S. Walawalkar and S. Capstick, Phys. Rev. D 60 054030(1999) [22] G. Lopez Castro and A. Mariano, Phys. Lett. B 517 , 339 (2001) [arXiv:nucl-th/0006031]; Nucl. Phys. A 697 , 440 (2002) [arXiv:nucl-th/0010045]. 11