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<div class=""><font size="4" class="">Dear All, </font></div>
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<div class=""><font size="4" class="">Here is reminder for the theory seminars next week. </font></div>
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<div class=""><font size="4" class=""><span style="font-family: Calibri, Helvetica, sans-serif;" class=""><font color="#4f7a28" class="">Bluejeans connection:</font> </span><span class="" style="font-family: Calibri, Helvetica, sans-serif; background-color: rgb(255, 255, 255); color: rgb(0, 111, 201);"><a href="https://bluejeans.com/610445877" class="">https://bluejeans.com/610445877</a> </span></font></div>
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<div class=""><font color="#0061ff" size="4" class=""><b class="">Theory Seminar: Monday, May 20, 1:00 – 2:00pm, Room L102</b></font></div>
<div class=""><span role="heading" aria-level="1" id="rAECCd" class=""><font size="4" class=""><b class="">Henry Lamm</b> (University of Maryland)</font></span></div>
<div class=""><font size="4" class=""><b class="">Title:</b> Model-independent bounds on semi-leptonic decays $B_c^+$</font></div>
<div class=""><font size="4" class=""><b class="">Abstract:</b> Model-independent bounds on $R(J/\psi) \! \equiv \!\mathcal{BR} (B_c^+ \rightarrow J/\psi \, \tau^+\nu_\tau)/\mathcal{BR} (B_c^+ \rightarrow J/\psi \, \mu^+\nu_\mu)$ are obtained through a combination
of dispersive relations, heavy-quark relations at zero-recoil, and the limited existing form factor determinations from lattice QCD\@. The resulting 95\% confidence-level bound, $0.20\leq R(J/\psi)\leq0.39$, agrees with the recent LHCb result at $1.3 \, \sigma$,
and removes the dominant model-dependent uncertainty from theory predictions. Using the same techniques, a prediction of $R(\eta_c)=0.29(5)$ is obtained.</font></div>
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<div class=""><font color="#0061ff" size="4" class=""><b class="">Theory Seminar: Wednesday, May 22, 1:00 – 2:00pm, Room L102</b></font></div>
<div class=""><font size="4" class=""><b class="">Elliot Leader</b> (Imperial College), </font></div>
<div class=""><b class=""><font size="4" class="">Title: </font></b><font size="4" class="">Can LASER optics resolve the remaining particle physics angular momentum controversy? </font></div>
<div class=""><font size="4" class=""><b class="">Abstract:</b> We explain why the claim which gave rise to the original photon angular momentum controversy i.e. the claim that the photon total angular momentum can be split, in a gauge invariant way, into
orbital and spin parts,is unquestionably incorrect. There remains the question as to which version of angular momentum, the Poynting one used in classical E.M. or the canonical one usually used in QED, is the physically correct one. We suggest this can be
settled experimentally.</font></div>
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<div class=""><font size="4" class="">Thank you.</font></div>
<div class=""><font size="4" class="">Carlota, Miguel, Raza</font></div>
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