arXiv subjects

L. Ahrens

Publications and source records attributed to L. Ahrens.

2 recordsLinked to original sources

arXiv2026

Evidence for the decay $B^0 \to μ^+ μ^-$ and improved measurements of the decay $B^0_s \to μ^+ μ^-$

The first single-experiment evidence for the rare decay $B^0 \to μ^+ μ^-$ and the world's most precise measurements of the $B^0_s \to μ^+ μ^-$ branching fraction and effective lifetime are reported. The results are obtained using Run 3 proton-proton collision data corresponding to an integrated luminosity of 18 fb$^{-1}$ recorded with the LHCb Upgrade I detector at a centre-of-mass energy of $13.6$ TeV between 2024 and 2025. Their combination with the Run 1 and Run 2 LHCb results further improves the precision. All measurements are found to be in agreement with the Standard Model expectations.

hep-ex↗

arXiv2007

RHIC Low-Energy Challenges and Plans

There is significant interest in RHIC heavy ion collisions at $\sqrt{s_{NN}}=$5--50 GeV, motivated by a search for the QCD phase transition critical point. The lowest energies for this search are well below the nominal RHIC gold injection collision energy of $\sqrt{s_{NN}}=19.6$ GeV. There are several operations challenges at RHIC in this regime, including longitudinal acceptance, magnet field quality, lattice control, and luminosity monitoring. We report on the status of work to address these challenges, including results from beam tests of low energy RHIC operations with protons and gold, and potential improvements from different beam cooling scenarios.

physics.acc-ph↗