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<p class="MsoNormal"><o:p> </o:p></p>
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<span style="font-size:12.0pt;line-height:105%;font-family:"Times New Roman",serif"> </span></p>
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<b><span style="font-size:28.0pt;line-height:105%;font-family:"Times New Roman",serif;color:black">Virtual Physics Division Seminar </span></b></p>
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<span style="font-size:12.0pt;line-height:105%;font-family:"Times New Roman",serif;color:black"> </span></p>
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<span class="xxvalue"><b><span style="font-size:28.0pt;line-height:105%;font-family:"Times New Roman",serif;color:black">The MARATHON Marathon </span></b></span></p>
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<span class="xxvalue"><b><span style="font-size:20.0pt;line-height:105%;font-family:"Times New Roman",serif;color:black">Hanjie Liu, Christopher Cocuzza, Efrain Segarra </span></b></span></p>
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<span class="xxvalue"><b><span style="font-size:14.0pt;line-height:105%;font-family:"Times New Roman",serif;color:black">University of Massachusetts Amherst, Temple University, Massachusetts Institute of Technology </span></b></span></p>
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<p class="xxxmsonormal"><b><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:black">The recently released MARATHON results have generated considerable interest with two derivative papers already on the arXiv. This Friday we will have a
MARATHON Marathon with Hanjie Liu (Univ. of Mass. Amherst), Christopher Cocuzza (Temple), and Efrain Segarra (MIT) presenting these new results. We will loosely follow an APS invited session format with each presenter having thirty minutes to present though
we have allow considerably more time for questions and discussions. </span></b></p>
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<b><span style="font-size:14.0pt;line-height:105%;font-family:"Times New Roman",serif;color:black">Friday, April 30, 2021 </span></b></p>
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<b><span style="font-size:14.0pt;line-height:105%;font-family:"Times New Roman",serif;color:black">12:00 pm – 2:30 pm </span></b></p>
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<span style="font-size:14.0pt;line-height:105%;font-family:"Times New Roman",serif;color:black"><a href="https://bluejeans.com/245615984" target="_blank" title="https://bluejeans.com/245615984">https://bluejeans.com/245615984</a><b> </b></span></p>
<p class="xxxmsonormal"><b><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:black"> </span></b></p>
<p align="center" style="text-align:center"><b><span style="font-size:18.0pt;font-family:"Times New Roman",serif;color:black">Abstracts: </span></b></p>
<p align="center" style="text-align:center"><b><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:black">The Measurement of the Nucleon F2n/F2p Structure Function Ratio from the MARATHON Experiment</span></b><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:black"> </span></p>
<p style="text-align:justify;text-justify:inter-ideograph"><b><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:black"> </span></b><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:black"> </span></p>
<p align="center" style="text-align:center"><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:black">Hanjie Liu (Univ. of Mass. Amherst) </span></p>
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<i><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:black">The ratio of neutron structure function to that of proton F2n/F2p is one of the best methods to extract d/u quark ratio. While the F2n/F2p extracted from deuteron deep inelastic
scattering data has large systematic uncertainty at high x (x>0.7) from model dependent nuclear corrections, the MARATHON experiment, which ran in spring 2018, uses a novel method. It performed deep inelastic electron scattering off tritium and helium-3 mirror
nuclei to measure F2n/F2p over the range x=0.195 to x=0.825. Since tritium and helium-3 are mirror nuclei, theoretical uncertainties are expected to be largely canceled out in the ratio. The results of F2n/F2p from the MARATHON experiment was recently posted
in arxiv. An overview of the MARATHON experiments and the results will be presented. </span></i></p>
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<p class="xxxmsonormal" align="center" style="text-align:center"><b><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:black">First Evidence of Isovector EMC effect from Global QCD Analysis with MARATHON Data</span></b><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:black"> </span></p>
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<p class="xxxmsonormal" align="center" style="text-align:center"><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:black">Christopher Cocuzza (Temple) </span></p>
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<p class="xxxmsonormal"><i><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:black">I will report the results of a Monte Carlo global QCD analysis of unpolarized parton distribution functions (PDFs), including for the first time constraints
from ratios of 3He to 3H structure functions recently obtained by the MARATHON experiment at Jefferson Lab. This simultaneous analysis of nucleon PDFs and nuclear effects in A=2 and A=3 nuclei reveals the first indication for an isovector nuclear EMC effect
in light nuclei. Thus, while the MARATHON data yield relatively weak constraints on the F2n/F2p neutron to proton structure function ratio and the d/u PDF ratio, the data suggest a strongly enhanced nuclear effect on the d-quark PDF in the bound proton. </span></i></p>
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<p class="xxxmsonormal" align="center" style="text-align:center"><b><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:black">Nucleon Off-shell Structure and the Free Neutron Valence Structure from A=3 Inclusive Electron Scattering
</span></b><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:black"> </span></p>
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<p class="xxxmsonormal" align="center" style="text-align:center"><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:black">Efrain Segarra (MIT) </span></p>
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<p class="xxxmsonormal"><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:black;background:white">While there are large amounts of proton structure measurements, data on the structure of the neutron is
<i>much more spars as experiments typically extract the structure of neutrons from measurements of light atomic nuclei using model-dependent corrections for nuclear effects.
</i></span><i><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:black"> <span style="background:white">Here we evaluate the model dependence of this extraction by examining a wide range of models including the effect of using instant-form
and light-cone nuclear wave functions and several different parameterizations of nucleon modification effects, including those with and without isospin dependence. We find that, while the data cannot differentiate among the different models of nuclear structure
and nucleon modification, they consistently prefer a neutron-to-proton structure function ratio of at </span><span style="border:none windowtext 1.0pt;padding:0in">xB→1</span><span style="background:white"> of </span></span></i><i><span style="font-size:12.0pt;font-family:"Cambria Math",serif;color:black;border:none windowtext 1.0pt;padding:0in">∼</span></i><i><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:black;border:none windowtext 1.0pt;padding:0in">0.4</span></i><i><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:black;background:white"> with
a typical uncertainty (</span></i><i><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:black;border:none windowtext 1.0pt;padding:0in">1σ</span></i><i><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:black;background:white">)
of </span></i><i><span style="font-size:12.0pt;font-family:"Cambria Math",serif;color:black;border:none windowtext 1.0pt;padding:0in">∼</span></i><i><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:black;border:none windowtext 1.0pt;padding:0in">0.05</span></i><i><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:black;background:white"> and </span></i><i><span style="font-size:12.0pt;font-family:"Cambria Math",serif;color:black;border:none windowtext 1.0pt;padding:0in">∼</span></i><i><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:black;border:none windowtext 1.0pt;padding:0in">0.10</span></i><i><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:black;background:white"> for
isospin-independent and isospin-dependent modification models, respectively. While strongly favoring SU(6) symmetry breaking models based on perturbative QCD and the Schwinger-Dyson equation calculation, the MARATHON data do not completely rule out the scalar
di-quark models if an isospin-dependent modification exist.</span></i><i><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:black"> </span></i></p>
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<b><span style="font-size:18.0pt;line-height:105%;font-family:"Times New Roman",serif;color:black">Friday, April 30, 2021 </span></b></p>
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<b><span style="font-size:18.0pt;line-height:105%;font-family:"Times New Roman",serif;color:black">12:00 pm – 2:30 pm </span></b></p>
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<span style="font-size:12.0pt;line-height:105%;font-family:"Times New Roman",serif;color:black"><a href="https://bluejeans.com/245615984" target="_blank" title="https://bluejeans.com/245615984"><span style="font-size:20.0pt;line-height:105%">https://bluejeans.com/245615984</span></a></span><b><span style="font-size:20.0pt;line-height:105%;font-family:"Times New Roman",serif;color:black"> </span></b></p>
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<p class="xmsonormal"><b><i><span style="font-size:12.0pt;color:black">Stephanie Tysor</span></i></b></p>
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