Difference between revisions of "B1pi tests Sep. 2011"
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| − | In the following the GlueX Monte Carlo and and analysis code revision 8233 as of end of August 2011 is used. 50000 b1pi events are generated for two geometries. One is the current standard geometry with a model of the BCAL readout including a copper cooling plate. A second geometry is identical with the exception that the BCAL readout part has been removed. This was done to see the impact of the BCAL readout on the reconstruction of these events. The event vertex is randomly distributed within the 30cm long target along the z-axis. | + | <b>In the following the GlueX Monte Carlo and and analysis code revision 8233 as of end of August 2011 is used. 50000 b1pi events are generated for two geometries. One is the current standard geometry with a model of the BCAL readout including a copper cooling plate. A second geometry is identical with the exception that the BCAL readout part has been removed. This was done to see the impact of the BCAL readout on the reconstruction of these events. The event vertex is randomly distributed within the 30cm long target along the z-axis.<br> |
| − | As one can see there is no obvious difference in the reconstructed mass distributions for pi0, omega, rho, b1 and X regarding the presence of the BCAL readout in the geometry of the simulation.<br><br> | + | As one can see there is no obvious difference in the reconstructed mass distributions for pi0, omega, rho, b1 and X regarding the presence of the BCAL readout in the geometry of the simulation.<br><br> </b> |
The <b>pi0</b> mass (left=standard geometry, right=no Bcal readout):<br> | The <b>pi0</b> mass (left=standard geometry, right=no Bcal readout):<br> | ||
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| + | <b> | ||
To investigate the effect of the BCAL readout we look next at the distributions of photons and charged tracks as a function of angles as well as 2-dim. distributions of energy vs. angle for the different particle tracks.<br> | To investigate the effect of the BCAL readout we look next at the distributions of photons and charged tracks as a function of angles as well as 2-dim. distributions of energy vs. angle for the different particle tracks.<br> | ||
| + | </b> | ||
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| + | <b>Photon angular distribution</b> (left=standard geometry, right=no Bcal readout):<br> | ||
| + | [[Image:b1pi_standardgeom_photons_theta.gif|400px]] [[Image:b1pi_nobcalreadoutgeom_photons_theta.gif|400px]] | ||
| + | <br> | ||
| + | <b>In the above plot the black are the thrown MC photons and in red are the reconstructed photons. Since 50k events are thrown we have 100k photons thrown. About 30% more photons are reconstructed. While there are always more photons reconstructed at all angles a significant overshot is seen at angles above 10.5 degree. This is the effect of shallow impact angles into the BCAL. More on this later. Also there is a small bump aove 40 degree. This is caused by protons that are miss identified as photons. This will become apparent when examining more plots below.</b> | ||
Revision as of 10:15, 2 September 2011
In the following the GlueX Monte Carlo and and analysis code revision 8233 as of end of August 2011 is used. 50000 b1pi events are generated for two geometries. One is the current standard geometry with a model of the BCAL readout including a copper cooling plate. A second geometry is identical with the exception that the BCAL readout part has been removed. This was done to see the impact of the BCAL readout on the reconstruction of these events. The event vertex is randomly distributed within the 30cm long target along the z-axis.
As one can see there is no obvious difference in the reconstructed mass distributions for pi0, omega, rho, b1 and X regarding the presence of the BCAL readout in the geometry of the simulation.
The pi0 mass (left=standard geometry, right=no Bcal readout):
Here and in the following the black histograms are the thrown Monte Carlo values however the photon energies and charged particle momenta are smeared before the masses are reconstructed.
The omega mass (left=standard geometry, right=no Bcal readout):
The b1 mass (left=standard geometry, right=no Bcal readout):
The X mass (left=standard geometry, right=no Bcal readout):
To investigate the effect of the BCAL readout we look next at the distributions of photons and charged tracks as a function of angles as well as 2-dim. distributions of energy vs. angle for the different particle tracks.
Photon angular distribution (left=standard geometry, right=no Bcal readout):
In the above plot the black are the thrown MC photons and in red are the reconstructed photons. Since 50k events are thrown we have 100k photons thrown. About 30% more photons are reconstructed. While there are always more photons reconstructed at all angles a significant overshot is seen at angles above 10.5 degree. This is the effect of shallow impact angles into the BCAL. More on this later. Also there is a small bump aove 40 degree. This is caused by protons that are miss identified as photons. This will become apparent when examining more plots below.
