def __init__(self,row,i):
particle.__init__(self,row,i)
self._mass = 0.0 #in GeV
def __init__(self,row,i):
particle.__init__(self,row,i)
self._mass = 0.000510998928 #in GeV
def __init__(self,row,i):
particle.__init__(self,row,i)
self._mass = 0.1056583715#in GeV
