`PhaseSpace3` and `PhaseSpace3s` do not agree

[VanyaBelyaev]

Ostap::Math::PhaseSpace3 and Ostap::Math::PhaeSpace3s do not agree

import ROOT, math
from   ostap.core.pyrouts  import Ostap
from   ostap.logger.logger import getLogger

logger = getLogger ("ChicPi")

PS3 = Ostap.Math.PhaseSpace3  ## <-- HERE 
PS3 = Ostap.Math.PhaseSpace3s ## <-- HERE  
GeV = 1.0
MeV = 0.001 * GeV


m_chic1 = 3510.67 * MeV
m_K     = 493.677 * MeV
m_pi    = 139.570 * MeV
m_p     = 938.272 * MeV
m_Lb    = 5619.60 * MeV


ps_pi = PS3 ( m_chic1 , m_pi , m_p )
ps_K  = PS3 ( m_chic1 , m_K  , m_p )

logger.info ( "PS(pi)                       : %s "  % ps_pi ( m_Lb ) )
logger.info ( "PS(K)                        : %s "  % ps_K  ( m_Lb ) )
r = ps_pi ( m_Lb ) / ps_K ( m_Lb )

theta_C = 13.02 * math.pi / 180.0
tc2     = math.tan (  theta_C ) **2
logger.info ( "PS(pi)/PS(K)                 : %s "  % r    )
logger.info ( "tan^2 theta_C                : %s "  % tc2  )
logger.info ( "PS(pi)/PS(K) * tan^2 theta_C : %s "  % ( r  * tc2 ) )