[Theory-seminars] seminars next week

[Raza Sufian]

Dear All,

Here is reminder for the theory seminars next week.

Bluejeans connection: https://bluejeans.com/610445877


Theory Seminar: Monday, May 20, 1:00 – 2:00pm, Room L102
Henry Lamm (University of Maryland)
Title: Model-independent bounds on semi-leptonic decays $B_c^+$
Abstract: 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.

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Theory Seminar: Wednesday, May 22, 1:00 – 2:00pm, Room L102
Elliot Leader (Imperial College),
Title: Can LASER optics resolve the remaining particle physics angular momentum controversy?
Abstract: 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.

Thank you.
Carlota, Miguel, Raza
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