<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Theory Seminar<br class="">Monday, July 20, 2015<br class="">1:00 p.m.<br class="">CEBAF Center, L102<br class=""><br class="">Speaker: Cesar Fernandez-Ramirez (Jefferson Lab)<br class=""><br class="">Title: “Amplitude Analysis of KN Scattering"<br class=""><br class="">Abstract: I present a unitary multichannel model for $\bar{K}N$ scattering in the resonance region<div class="">that fulfills unitarity, it has the correct analytical properties for the amplitudes once they are extended </div><div class="">to the complex-s plane and the partial waves have the right threshold behavior. </div><div class="">To determine the parameters of the model we have fitted </div><div class="">single-energy partial waves up to J=7/2 and up to 2.15 GeV of energy </div><div class="">in the center of mass reference frame obtaining the poles of the Lambda and Sigma resonances,</div><div class="">which are compared to previous analysis.</div><div class="">We provide the most comprehensive picture of the S=-1 hyperon spectrum to the date</div><div class="">and some important differences are found between the available analyses deeming the</div><div class="">gathering of further experimental information on KN scattering</div><div class="">mandatory in order to make progress in the assessment of the </div><div class="">hyperon spectrum. I will also comment on the Lambda(1405) and its nature.</div><div class=""><br class=""></div>
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<div style="color: rgb(0, 0, 0); letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="color: rgb(0, 0, 0); letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="orphans: auto; text-align: start; text-indent: 0px; widows: auto; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class=""><div class="">- - - - -</div><div class="">Dr. César Fernández-Ramírez</div><div class=""><br class=""></div><div class="">Jefferson Lab Theory Center</div><div class="">12000 Jefferson Ave., Newport News, VA 23606, USA</div><div class=""><br class=""></div><div class="">Phone: (+1) 757-269-7844</div><div class="">Fax: (+1) 757-269-7002</div><div class="">E-mail: <a href="mailto:cesar@jlab.org" class="">cesar@jlab.org</a></div></div><div style="color: rgb(0, 0, 0); letter-spacing: normal; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><br class=""></div></div></div><br class="Apple-interchange-newline"></div><br class="Apple-interchange-newline"><br class="Apple-interchange-newline">
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