2019 Fall Graduate Colloquium Series: Jeff Lee/Calvin Carmichael

DateSeptember 27, 2019Time3:35 - 5:00 pm
LocationBaylor Sciences Building, Room E.125
Description
2019 Fall Graduate Colloquium Series

Jeff Lee, P. Phys.

Relativistic Drag and Emission Radiation Pressures in an Isotropic Photonic Gas

By invoking the relativistic spectral radiance, as derived by Lee and Cleaver, the drag radiation pressure of a relativistic planar surface moving through an isotropic radiation field, with which it is in thermal equilibrium, is determined in inertial and non-inertial frames. The forward- and backward-directed emission radiation pressures are also derived and compared. A fleeting (inertial frames) or ongoing (some non-inertial frames) Carnot cycle is shown to exist as a result of an inter-surfaces temperature gradient. The drag radiation pressure on an object with an arbitrary frontal geometry is also described.

Relativistic drag and emission radiation pressures in an isotropic photonic gas
Jeffrey S. Lee and Gerald B. Cleaver
Modern Physics Letters A
Vol. 31, No. 19 (2016) 1650118 (14 pages)
World Scientific Publishing Company
DOI: 10.1142/S0217732316501182

Calvin Carmichael

Observation of the Z → ψℓ+ℓ− Decay in pp Collisions at √s =13TeV

This Letter by A.M. Sirunyan et al* presents the observation of the rare Z boson decay Z → ψℓl ℓ−. Here, ψ represents contributions from direct J/ψ and ψ(2S)→ J/ψX, ℓ+ℓ− is a pair of electrons or muons, and the J/ψ meson is detected via its decay to μ+μ−. The sample of proton-proton collision data, collected by the CMS experiment at the LHC at a center-of-mass energy of 13 TeV, corresponds to an integrated luminosity of 35.9 fb−1.The signal is observed with a significance in excess of 5 standard deviations. After subtraction of the ψ(2S)→ J/ψX contribution, the ratio of the branching fraction of the exclusive decay Z → J=ψℓ+ℓ− to the decay Z → μ+μ−μ+μ− within a fiducial phase space is measured to be B(Z → J/ψℓ+ℓ−) /B(Z → μ+μ−μ+μ−) = 0.67±0.18(stat)±0.05(syst).

For more information contact: Dr. Kenneth Park 254-710-2282
PublisherDepartment of Physics
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