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Nt1310 Unit 5 Lab Report

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The missing mass spectra after selecting $\omega\to\pi^0\gamma$ exclusive final state for different monochromatic $\gamma$ selection criteria are presented in Fig.~\ref{Fmonosys145} and Fig.~\ref{Fmonosys15} for 1.45~GeV and 1.5~GeV, respectively. The missing mass fit for the final cut is shown in Fig.~\ref{mmpi0g1} for both energies. The histograms in Fig.~\ref{Fmonosys145} and Fig.~\ref{Fmonosys15} are arranged in the decreasing order of efficiency ($\epsilon_{exc}$) from (a) to (h). It is seen in the figures that the monochromatic $\gamma$ cuts are making an immense effect on the kinematics of the backgrounds as well as on the signal. The phase space of the spectra is changed for different monochromatic $\gamma$ cuts. The line shape …show more content…

The branching ratio ($BR^{measured}_{\omega\to\pi^0\gamma}$) for both energies and combined data set are measured for each cut, as described in Equation~\ref{Osdfitsysbrf}. The $N_{\omega}^{\circ}$ used for the calculation of $BR^{measured}_{\omega\to\pi^0\gamma}$ is %constant for each cut, which is the one obtained from the final measurement, given in Table~\ref{inclmm}. The measured values for $N_{\omega\to\pi^0\gamma}^{\circ}$ and $BR^{measured}_{\omega\to\pi^0\gamma}$ are also written in Table~\ref{Tmonosyseff}. In an ideal situation the efficiency corrected number $N_{\omega\to\pi^0\gamma}^{\circ}$ and hence the branching ratio $BR^{measured}_{\omega\to\pi^0\gamma}$ should remain constant throughout and should be same as for the final measurement ($X(f)$). In that case, there must be no systematic effect due the monochromatic $\gamma$ selection criterion. As it can be seen in Table~\ref{Tmonosyseff} that this is not the case here and $N_{\omega\to\pi^0\gamma}^{\circ}$ and $BR^{measured}_{\omega\to\pi^0\gamma}$ are decreasing with the efficiency expect 7$^{th}$ and 8$^{th}$ entry. The uncertainties arises due to the systematic effect of the monochromatic $\gamma$

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