Post #3: Correcting for Beam Effects in the Qweak Experiment

I continue here where I left off before in my last post. This is my final post, and it details the results and conclusions of my research:

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Post #2: Correcting for Beam Effects in the Qweak Experiment

In this post, I will describe in greater detail the underpinnings of both the Qweak Experiment and my work. The material is extracted from a paper that I wrote for the REU (Research Experience for Undergraduates) program in physics. I’ll spare anyone reading this from the math in the actual paper, which I will describe qualitatively here:

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Post #1: Correcting for Beam Effects in the Qweak Experiment

First of all, I want to start off with a summary and explanation of my abstract and purpose: I am working to correct data measured by the Qweak experiment at Jefferson Lab for natural beam imperfections which create ‘false asymmetries’ in the data. This is done by calculating correlations between different beam properties and the data (asymmetries measured by the main detectors) and removing these correlations from the data. Correlations are not calculated in the same way that one might in a stats class. They are calculated for each successive event (there are some 90,000 events in each data file that I use) so that precision is not lost as one calculates over such a large set of data. These values are then used to correct the main detector data, removing the ‘false asymmetries’ due to the beam motion. Greater explanation of this process and results will follow in subsequent blog posts.

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Abstract: Correcting for Beam Effects in the Qweak Experiment

The purpose of this freshman research project will be to expand on my current work to correct for beam effects in asymmetries measured for use in the Qweak experiment, an ongoing experiment based at the particle accelerator at Jefferson Lab (JLab) in Newport News, Virginia. The ultimate goal of the Qweak experiment is to calculate the weak charge of the proton by measuring the asymmetry of electrons scattering on protons in a liquid hydrogen target. The weak charge of the proton is used to find the weak mixing angle (sin2θw), a parameter used in the standard model of particle physics, our current best theory for explaining the nature of subatomic particles. The Qweak experiment is part of a search to identify phenomena beyond the standard model. The purpose of my work is to model the effect of beam properties on recorded asymmetries for each of the detectors in order to differentiate these effects from those due to the electron scattering. These beam properties include beam slope and position (with respect to X and Y), beam charge, and beam energy. Two methods for correcting for these effects, dubbed yield and asymmetry, will be compared.