Ciao Fabio,
>
> Hi
>
> I find three different topologies of events with tha same Mes value:
>
> 1) the case with nB0==0 and consecutive events.
> same mes value but different values for other variables
>
>
> TFile
> f2("/nfs/farm/babar/AWG18/ISL/sx-080702/newgenbb/B0/2001/unskgenb0-2001-new2001-1036.root")
> h1->Scan("mseB0:nB0:lowerID:primVtxX:primVtxY","mseB0>5.2221168&&mseB0<5.2221170")
>
> ************************************************************************
> * Row * mseB0 * nB0 * lowerID * primVtxX * primVtxY *
> ************************************************************************
> * 2279 * 5.2221169 * 1 * -1.28e+09 * 0.0859066 * 0.3366443 *
> * 2280 * 5.2221169 * 0 * -1.28e+09 * 0.0976630 * 0.3395716 *
> * 2281 * 5.2221169 * 0 * -1.28e+09 * 0.1123376 * 0.3270976 *
> ************************************************************************
>
this first one looks like a fantastic feature of root. If asked "what is
the mass of the B0 in this event where you have no B0", it replies with
the last available value instead of the more sensible paw reply
"what?!?!".
I would not worry about this, I assume we are smarter and don't do
anything if there are no Bs ...
>
> 2) the case with nB0==1 and not consecutive events. also in this case same
> mes but differents values for other variables
>
> TFile
> f2("/nfs/farm/babar/AWG18/ISL/sx-080702/newgenbb/B0/2001/unskgenb0-2001-new2001-1036.root")
>
> h1->Scan("mseB0:nB0:lowerID:primVtxX:primVtxY","mseB0>5.2220712&&mseB0<5.2221&&nB0==1")
> ************************************************************************
> * Row * mseB0 * nB0 * lowerID * primVtxX * primVtxY *
> ************************************************************************
> * 82 * 5.2220983 * 1 * 2.133e+09 * 0.0703760 * 0.3292633 *
> * 995 * 5.2220983 * 1 * -1.94e+09 * 0.1155018 * 0.3324499 *
> ************************************************************************
>
>
this is a wierd case. The B0 masses (m0B0 and massB0 for these candidates)
are completely different. This looks like a quantization of the value that
mes can assume. Could you recompute mes at anaRecoil level and check what
would you get?
Note that we are getting this quantity from BtaBVariables::m_ES and the
documentation reads
// m_ES is the beam energy substituted mass, calculated from the lab four
// momentum of the beam system and the lab three momentum of the
candidate.
// (originially proposed by W. Dunwoodie,
// http://www.slac.stanford.edu/~wmd/bbkinematics/kinematics.note; see
// also B.A.D. 53.)
we might fall in some rounding trap.
>
> 3) the case with real duplicated events( but I can find them only in
> continuum ccbar)
>
> TFile
> f1("/nfs/farm/babar/AWG8/ISL/sx-071802/gencc/output/outputdir/gencc-2000-old2000-1.root")
>
> h1->Scan("mseB0:nB0:lowerID:primVtxX:primVtxY","mseB0>5.23132&&mseB0<5.23136")
>
> ************************************************************************
> * Row * mseB0 * nB0 * lowerID * primVtxX * primVtxY *
> ************************************************************************
> * 373 * 5.2313356 * 1 * 933944660 * 0.1179052 * 0.3384617 *
> * 374 * 5.2313356 * 0 * 933847757 * 0.1138248 * 0.3475763 *
> * 375 * 5.2313356 * 0 * 933962993 * 0.1176636 * 0.3080920 *
> * 417 * 5.2313356 * 1 * 933944660 * 0.1179052 * 0.3384617 *
> ************************************************************************
>
I assume this is a bookkeeping hickup, but it is pretty rare, correct?
thanks
ric
