<html><body><div style="font-family: arial, helvetica, sans-serif; font-size: 12pt; color: #000000"><div><div style="" data-mce-style=""><p style="text-align: center; border: medium none; padding: 0in; margin: 0px;" data-mce-style="text-align: center; padding: 0in; margin: 0px;"><strong style="" data-mce-style=""><span style="font-size: 48pt; line-height: 107%; font-family: "times new roman",serif;" data-mce-style="font-size: 48pt; line-height: 107%; font-family: 'times new roman',serif;">Physics Seminar</span></strong></p><p style="text-align: center; margin: 0px;" data-mce-style="text-align: center; margin: 0px;"><strong style="" data-mce-style=""><span style="font-size: 20pt; font-family: "times new roman",serif;" data-mce-style="font-size: 20pt; font-family: 'times new roman',serif;">Andrew Puckett</span></strong></p><p style="text-align: center; margin: 0px;" data-mce-style="text-align: center; margin: 0px;"><strong style="" data-mce-style=""><span style="font-size: 20pt; font-family: "times new roman",serif;" data-mce-style="font-size: 20pt; font-family: 'times new roman',serif;">University of Connecticut</span></strong></p><p style="text-align: center; margin: 0px;" data-mce-style="text-align: center; margin: 0px;"><span style="font-size: 17pt; font-family: cmr17;" data-mce-style="font-size: 17pt; font-family: cmr17;"> </span></p><p style="text-align: center; margin: 0px;" data-mce-style="text-align: center; margin: 0px;"><em style="" data-mce-style=""><span style="font-size: 18pt; font-family: "times new roman",serif;" data-mce-style="font-size: 18pt; font-family: 'times new roman',serif;">Polarization transfer observables in elastic electron-proton</span></em></p><p style="text-align: center; margin: 0px;" data-mce-style="text-align: center; margin: 0px;"><em style="" data-mce-style=""><span style="font-size: 18pt; font-family: "times new roman",serif;" data-mce-style="font-size: 18pt; font-family: 'times new roman',serif;">scattering at Q<sup style="" data-mce-style="">2 </sup>= <span class="Object" id="OBJ_PREFIX_DWT698_com_zimbra_phone"><a href="callto:2.5,%205.2,%206.8" onclick="window.top.Com_Zimbra_Phone.unsetOnbeforeunload()" data-mce-href="callto:2.5,%205.2,%206.8">2.5, 5.2, 6.8</a></span> and 8.5 GeV<sup style="" data-mce-style="">2</sup></span></em></p><p style="margin: 0px; line-height: normal;" data-mce-style="margin: 0px; line-height: normal;"><span style="font-size: 9pt; font-family: cmbx9;" data-mce-style="font-size: 9pt; font-family: cmbx9;"> </span></p><p style="margin: 0px; line-height: normal;" data-mce-style="margin: 0px; line-height: normal;"><span style="font-size: 9pt; font-family: cmbx9;" data-mce-style="font-size: 9pt; font-family: cmbx9;"> </span></p><p style="margin: 0px; line-height: normal;" data-mce-style="margin: 0px; line-height: normal;"><span style="font-size: 9pt; font-family: cmbx9;" data-mce-style="font-size: 9pt; font-family: cmbx9;"> </span></p><p style="margin: 0px; text-align: center; line-height: normal;" data-mce-style="margin: 0px; text-align: center; line-height: normal;"><strong style="" data-mce-style=""><span style="font-size: 18pt; font-family: "times new roman",serif;" data-mce-style="font-size: 18pt; font-family: 'times new roman',serif;">Abstract:</span></strong></p><p style="margin: 0px; line-height: normal;" data-mce-style="margin: 0px; line-height: normal;"><span style="font-size: 9pt; font-family: cmbx9;" data-mce-style="font-size: 9pt; font-family: cmbx9;"> </span></p><p style="margin: 0px; line-height: normal;" data-mce-style="margin: 0px; line-height: normal;"><span style="font-size: 9pt; font-family: cmbx9;" data-mce-style="font-size: 9pt; font-family: cmbx9;"> </span></p><p style="margin: 0px; line-height: normal;" data-mce-style="margin: 0px; line-height: normal;">Electromagnetic form factors (EMFF) are among the most fundamental measurable properties of nucleon structure. The study of nucleon EMFFs at large momentum transfer Q<sup style="" data-mce-style="">2</sup> is currently a unique worldwide capability of CEBAF. The precise polarization transfer (PT) measurements of the proton's electromagnetic form factor ratio G<sup style="" data-mce-style="">p</sup><sub style="" data-mce-style="">E</sub>/G<sup style="" data-mce-style="">p</sup><sub style="" data-mce-style="">M</sub> from Halls A and C, covering a wide range of Q<sup style="" data-mce-style="">2</sup>, are among the most cited results from Jefferson Lab, owing to the surprising discovery of the rapid decrease of the proton form factor ratio G<sup style="" data-mce-style="">p</sup><sub style="" data-mce-style="">E</sub>/G<sup style="" data-mce-style="">p</sup><sub style="" data-mce-style="">M</sub> for Q<sup style="" data-mce-style="">2 </sup> ̰> 1 GeV<sup style="" data-mce-style="">2</sup>. These results strongly contradicted existing cross section data suggesting that G<sup style="" data-mce-style="">p</sup><sub style="" data-mce-style="">E</sub>/G<sup style="" data-mce-style="">p</sup><sub style="" data-mce-style="">M</sub> was approximately constant up to Q<sup style="" data-mce-style="">2</sup> ≈ 7 GeV<sup style="" data-mce-style="">2</sup>. The third and final set of experiments of the 6 GeV era dedicated to measuring polarization transfer in high-Q<sup style="" data-mce-style="">2</sup> elastic ep scattering was carried out in Hall C during fall-spring of 2007-2008. The GEp-III experiment (E04-108) extended the knowledge of the proton's electromagnetic form factor ratio to Q<sup style="" data-mce-style="">2</sup> = 8.5 GeV<sup style="" data-mce-style="">2</sup>. The companion GEp-2γ experiment (E04-019) produced precise (̰< 1% total uncertainty) measurements of the angular dependence of the PT observables at Q<sup style="" data-mce-style="">2</sup> = 2.5 GeV<sup style="" data-mce-style="">2</sup>, to search for or constrain effects beyond the Born approximation thought to be responsible for the disagreement between values of G<sup style="" data-mce-style="">p</sup><sub style="" data-mce-style="">E</sub> extracted from cross section and polarization data. The GEp-III/GEp-2γ collaboration has recently published the final results of both experiments, including the previously unpublished full-acceptance data from the GEp-2γ experiment, resulting in an approximate tripling of the statistics for two of the three production kinematics. In this seminar, I will review the common apparatus, the data analysis, and the final results of both experiments, and discuss the implications of the data for our understanding of the proton's structure, as well as lessons applicable to future experiments. I will then conclude with a brief overview of the high-Q<sup style="" data-mce-style="">2</sup> nucleon form factor program planned for the 12 GeV era of CEBAF.</p><p style="margin: 0px; line-height: normal;" data-mce-style="margin: 0px; line-height: normal;"> </p><p style="margin: 0px; line-height: normal;" data-mce-style="margin: 0px; line-height: normal;"><span style="font-size: 12pt; font-family: "times new roman",serif;" data-mce-style="font-size: 12pt; font-family: 'times new roman',serif;"> </span></p><p style="text-align: center; margin: 0px;" data-mce-style="text-align: center; margin: 0px;"><strong style="" data-mce-style=""><span style="font-size: 20pt; line-height: 107%; font-family: "times new roman",serif;" data-mce-style="font-size: 20pt; line-height: 107%; font-family: 'times new roman',serif;"><span class="Object" id="OBJ_PREFIX_DWT699_com_zimbra_date">Friday, January 26</span>, 2018</span></strong></p><p style="text-align: center; margin: 0px;" data-mce-style="text-align: center; margin: 0px;"><strong style="" data-mce-style=""><span style="font-size: 20pt; line-height: 107%; font-family: "times new roman",serif;" data-mce-style="font-size: 20pt; line-height: 107%; font-family: 'times new roman',serif;">11:00am</span></strong></p><p style="text-align: center; margin: 0px;" data-mce-style="text-align: center; margin: 0px;"><strong style="" data-mce-style=""><span style="font-size: 20pt; line-height: 107%; font-family: "times new roman",serif;" data-mce-style="font-size: 20pt; line-height: 107%; font-family: 'times new roman',serif;">CEBAF Auditorium</span></strong></p></div></div><div><br></div><div data-marker="__SIG_POST__">-- <br></div><div>Stephanie Tysor<br>Hall A Administrative Assistant<br>Thomas Jefferson National Accelerator Facility<br>(office)757-269-6005 (fax)757-269-5235</div></div></body></html>