Stefan Meinel
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Stefan Meinel
@stefanmeinel.bsky.social
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Associate Professor of Physics at University of Arizona, Tucson
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stefanmeinel.bsky.social
Good morning from Tucson, Arizona!
Full moon setting over the Tucson Mountains, with desert in the foreground. The Marriott Starr Pass hotel is seen nestled in the hills. Sunrise over the Rincon Mountains, with Saguaro cacti in the foreground. A yellow glow in the valley of Tucson.
October 7, 2025 at 2:08 PM
stefanmeinel.bsky.social
We had already pointed out in arxiv.org/abs/1912.05811 that the old estimate was incorrect, and had estimated B(Λb→J/ψΛ)=(3.7 ± 1.0) × 10−4, leading to the plot of the Λb→Λμ+μ− differential branching fraction shown below.
A plot from https://arxiv.org/abs/1912.05811 showing the Λb→Λμ+μ− differential branching fraction at high q^2. The LHCb measurement from https://arxiv.org/abs/1503.07138 is seen above the SM prediction, while our estimated correction of the LHCb measurement is seen close to the SM prediction.
September 17, 2025 at 9:20 AM
stefanmeinel.bsky.social
Updating the normalization to their new result substantially lowers the Λb→Λμ+μ− differential branching fraction, making the picture more consistent with the b→sl+l- anomalies in meson decays.
September 17, 2025 at 9:20 AM