Abstract
After reviewing earlier research on the energy of the J/psi data, an attempt to refine the energy boudaries was conducted. This was done by regraphing the data and changing the bin width to improve resolution. From this, it was determined that the J/psi particle has an energy between 3.08 and 3.12 GeV. Thus the energy of the J/psi determined agrees with the stated value of 3.0969 GeV
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Introduction
High energy particles tend to decay into lower energy particles. The J/psi particle is one such particle. The J/psi particle is a meson, a colorless particle containing 2 quarks, is comprised of a charm quark and an anti charm quark. When the J/psi particle decays it, it forms a muon and an antimuon. Since the muon and anti muon have opposite charges, they are bent in magnetic fields in opposite directions. While the Z bozon decays into a muon-antimuon pair as well, that pair is much higher in energy than the J/psi particle, so they have peaks in the chart in different locations. By analyzing the peaks in the data, an anomolous peak occurs around 3.1 GeV. While the peak is in the same area as the background noise, the background noise decrease with energy exponentially, and thus the energy of the J/psi peak can be determined.
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Procedures
In order to determine the energy of the J/psi peak, the plot of the muon-antimoun data for the J/psi particle is created. By setting the bin width to 0.04 GeV, the resolution needed to determine the J/psi peak can be seen. By looking at the graph, the exponential decay can be seen with an anomolous peak. Determining the energy of that peak, determines the energy of the J/psi particle.
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Results
By looking at the J/psi , muon-antimuon decay graph with a bin width of 0.04 GeV, it can be determined that the energy of the J/psi particle is between 3.08-3.12 GeV. The calibration curve, with a setting of 0.01 GeV bin width gives an energy of the J/psi particle to be 3.09 GeV. While more data points are needed to make a better resolution in the graph, the expected value does fall within the experimental value range. This data is confirmed with the data collected at CERN with masses of 3.07 GeV and 3.10 GeV. Since these values fall within the expected range, these decays are likely J/psi decays.
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Discussions & Conclusions
The experimental data confirmed the expected value for the J/psi particle. In order to get better resolution for the mass, more data points are needed.
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