1. Department of Physics, G. C. University Lahore, Katchery Road, 54000 Lahore, Pakistan
2. Salam Chair, G. C. University Lahore, Katchery Road, 54000 Lahore, Pakistan
3. Department of Physics, COMSATS Institute of Information Technology Lahore, Off Raiwand Road, P.O. 54000 Lahore, Pakistan