[d2n-analysis-talk] BB/LHRS tracks

[posik at jlab.org]

Hi all,

I have just finished implementing my proton cuts for selecting good events
in the LHRS looking at the 1-pass H2 runs that we took (1258-1262). Here
is a list of the cuts that I have used:

 tg_y ="(abs(L.tr.tg_y)<0.04)";

 tg_ph ="(abs(L.tr.tg_ph)<0.02)";

 tg_th ="((L.tr.tg_th>-0.035)&&(L.tr.tg_th<0.05))";

 tg_dp ="(abs(L.tr.tg_dp)<0.035)";

 ex_tg_p="((ExTgtCor_L.p<0.9)&&(ExTgtCor_L.p>0.83))";

 triggers = "((DL.evtypebits&1<<5)==(1<<5)&&(DL.edtpl==0))";

 energy="L.prl2.asum_c+L.prl1.asum_c)<100&&(L.prl2.asum_c+L.prl1.asum_c)>10)";

 prl="((L.prl2.asum_c>0)&&(L.prl1.asum_c>0))";

 track = "(L.tr.n==1)";
 vdc
="((L.vdc.u1.nclust==1)&&(L.vdc.v1.nclust==1)&&(L.vdc.u2.nclust==1)&&(L.vdc.v2.nclust==1))";

 cer = "(L.cer.asum_c==0)";

proton=
track+"&&"+triggers+"&&"+tg_y+"&&"+tg_ph+"&&"+tg_th+"&&"+tg_dp+"&&"+vdc+"&&"+cer+"&&"+prl+"&&"+energy+"&&"+ex_tg_p;

I made a plot of several of these cuts,with the blue histo being the cut
used. In LHRS_mom_cuts.png there is from left to right, ExtTgtCor_L.p,
L.tr.tg_dp and (L.prl2.asum_c+L.prl1.asum_c). In LHRS_target_cuts.png,
L.tr.tg_y, L.tr.tg_th and L.tr.tg_ph.

Any other cuts that I may have forgotten?

Next what I want to do is see how many tracks are in BB that correspond to
good protons in the LHRS. Ideally for every good proton track in the LHRS,
there should be a good electron track in BB. To look at this I generated
the plot tracks.png. The first (left most) plot shows all the tracks in
the LHRS with just a coin trigger (T5 in our case) between the LHRS and
BB. The second plot shows the tracks in the LHRS with the proton cut
applied. The third plots all electron tracks in the BB that correspond the
cuts for a proton to show up in the LHRS (plot BB.tr.n with proton cut).
The final (right most plot) shows the one track BB reconstruction which
satisfies a proton being in the LHRS(plot BB.tr.n with proton cut +
BB.tr.n==1 cut).

Taking the ratio of BB reconstructed one tracks with proton cuts and the
LHRS reconstructed one tracks with proton cut we get 0.93 So 93% of the
reconstructed one tracks in LHRS for a good proton show up in the BB
reconstructed one track.

I am still working on getting the H2 cross section for the proton in the
LHRS. I am right going over how to compute the solid angle acceptance of
the LHRS and trying to get the BBNormAna class to work in my replay to
extract the live time and the collected charge for the runs.


-matt
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