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<p class="xxmsonormal" align="center" style="text-align:center"><b><span style="font-size:28.0pt;font-family:"Times New Roman",serif">Hall D Seminar</span></b><o:p></o:p></p>
<p class="xxmsonormal" align="center" style="text-align:center"><span class="xxvalue"><b><span style="font-size:28.0pt;font-family:"Times New Roman",serif">Drew Smith<o:p></o:p></span></b></span></p>
<p class="xxmsonormal" align="center" style="text-align:center"><span class="xxvalue"><b><span style="font-size:28.0pt;font-family:"Times New Roman",serif">March 28, 2024 9:00-9:55 A.M.<o:p></o:p></span></b></span></p>
<p class="xxmsonormal" align="center" style="text-align:center"><span class="xxvalue"><b><span style="font-size:28.0pt;font-family:"Times New Roman",serif">University of Massachusetts, Amherst</span></b></span><o:p></o:p></p>
<p class="xxmsonormal" align="center" style="text-align:center"><b><span style="font-size:26.0pt;font-family:"Times New Roman",serif">Zoom:
</span></b><span style="font-size:16.0pt"><a href="https://jlab-org.zoomgov.com/j/1605062316?pwd=Z1dvRXJqc0Fmc0d6QkgzMTk5cFgvZz09">https://jlab-org.zoomgov.com/j/1605062316?pwd=Z1dvRXJqc0Fmc0d6QkgzMTk5cFgvZz09</a></span><o:p></o:p></p>
<p align="center" style="text-align:center"><i><span style="font-size:20.0pt;font-family:"Times New Roman",serif">Preliminary Analysis of the PrimEx-eta Experiment in Hall D<o:p></o:p></span></i></p>
<p align="center" style="text-align:center"><b><span style="font-size:18.0pt">Abstract:<o:p></o:p></span></b></p>
<p align="center" style="text-align:center"><span style="font-family:"Segoe UI",sans-serif">The $B&G(B meson is an interesting tool to study fundamental symmetries in low-energy QCD. In particular, the $B&G"*&C&C(B decay proceeds primarily through the chiral anomaly, and
its decay width is useful for providing critical input to extract fundamental parameters of QCD, such as the $B&G(B-$B&G(B' mixing angle and the light quark mass ratio. This decay width has been measured in the past using a fixed-target Primakoff experiment, however,
its result shows tension with the average of the results from several e+e- collider experiments. To address this discrepancy and to reduce the total uncertainty for the decay width, the PrimEx-eta fixed-target experiment in Hall D at Jefferson Lab (E12-10-0111)
is performing a precision measurement of the $B&G"*&C&C(B decay width using the Primakoff method. The data collection was completed in three separate run periods between 2019 and 2022, and the full analysis is currently underway. In this talk, I will discuss the status
of the experiment and show some preliminary results. Simultaneous with the $B&G(B decay width measurement, the total cross section for Compton scattering off atomic electrons was measured. This well-understood QED process is used to verify the overall systematic
uncertainties associated with a cross-section measurement in the forward direction, and provided one of the first absolute cross-section measurements in Hall D. In this talk, I will present the results for the integrated total Compton scattering cross section
measurement and discuss the associated systematic uncertainties.<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Patricia Cheeseboro<o:p></o:p></p>
<p class="MsoNormal">Admin Support Physics (Hall D)<o:p></o:p></p>
<p class="MsoNormal">Thomas Jefferson National Accelerator Facility<o:p></o:p></p>
<p class="MsoNormal">Jefferson Science Associates, LLC<o:p></o:p></p>
<p class="MsoNormal"><a href="mailto:pcheese@jlab.org">pcheese@jlab.org</a><o:p></o:p></p>
<p class="MsoNormal">(757) 269-5345<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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