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<p>Theory Center Seminar <br>
Monday, March 12, 2018 <br>
1:00 p.m. (coffee at 12:45 p.m.)<br>
CEBAF Center, Room L102 <br>
<br>
John Collins<br>
Penn State University<br>
<br>
<font size="+1"><b>Time to Retire a Myth in pQCD </b></font><br>
<br>
In many treatments of factorization in QCD, the logical starting
point is an unproved<br>
assertion that the cross sections in question are the convolution
product of "bare parton <br>
densities" and unsubtracted on-shell massless partonic cross
sections. This assertion is <br>
repeated many times in textbooks, lectures, as well as in papers.
I will show why it is <br>
physically and conceptually false. I will argue that this myth is
impeding progress in <br>
pQCD, because an incorrect starting point messes up efforts to
extend the methods. <br>
Moreover, the myth miseducates students. <br>
<br>
</p>
The link to remotely connect via Blue Jeans is available at<br>
<a class="moz-txt-link-freetext"
href="https://www.jlab.org/div_dept/theory/seminars/2018-spring-theory-seminar.html">https://www.jlab.org/div_dept/theory/seminars/2018-spring-theory-seminar.html</a>
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