Tue·May 4, 2021Tuesday·May 4, 2021

1. 01*

   Energy dependence of $\varphi$ meson production at forward rapidity in pp collisions at the LHC

   ALICE Collaboration

   The production of $\varphi$ mesons has been studied in pp collisions at LHC energies with the ALICE detector via the dimuon decay channel in the rapidity region $2.5<y<4$. Measurements of the differential cross section ${\mathrm{d}}^2\sigma /\mathrm{d}y\mathrm{d}{p}_{\mathrm{T}}$ are presented as a function of the transverse momentum ($p_{\mathrm{T}}$) at the center-of-mass energies $\sqrt{s}=5.02$, 8 and 13 TeV and compared with the ALICE results at midrapidity. The differential cross sections at $\sqrt{s}=5.02$ and 13 TeV are also studied in several rapidity intervals as a function of $p_{\mathrm{T}}$, and as a function of rapidity in three $p_{\mathrm{T}}$ intervals. A hardening of the $p_{\mathrm{T}}$-differential cross section with the collision energy is observed, while, for a given energy, $p_{\mathrm{T}}$ spectra soften with increasing rapidity and, conversely, rapidity distributions get slightly narrower at increasing $p_{\mathrm{T}}$. The new results, complementing the published measurements at $\sqrt{s}=2.76$ and 7 TeV, allow one to establish the energy dependence of $\varphi$ meson production and to compare the measured cross sections with phenomenological models. None of the considered models manages to describe the evolution of the cross section with $p_{\mathrm{T}}$ and rapidity at all the energies.

   nucl-exhep-exEPJC(2021)·9 citations
2. 02*

   Global Vision of Precision Measurements

   Jens Erler🇩🇪

   I summarize recent developments in electroweak precision physics and global fits. Expectations for future measurements, both at lower energies and the energy frontier, are also discussed.

   ↳ hep-phhep-exnucl-ex1 citation
3. 03*

   The proton charge radius

   Haiyan Gao🇺🇸 · Marc Vanderhaeghen🇩🇪

   Nucleons (protons and neutrons) are the building blocks of atomic nuclei, and are responsible for more than 99\% of the visible matter in the universe. Despite decades of efforts in studying its internal structure, there are still a number of puzzles surrounding the proton such as its spin, and charge radius. Accurate knowledge about the proton charge radius is not only essential for understanding how quantum chromodynamics (QCD) works in the non-perturbative region, but also important for bound state quantum electrodynamics (QED) calculations of atomic energy levels. It also has an impact on the Rydberg constant, one of the most precisely measured fundamental constants in nature. This article reviews the latest situation concerning the proton charge radius in light of the new experimental results from both atomic hydrogen spectroscopy and electron scattering measurements, with particular focus on the latter. We also present the related theoretical developments and backgrounds concerning the determination of the proton charge radius using different experimental techniques. We discuss upcoming experiments, and briefly mention the deuteron charge radius puzzle at the end.

   ↳ hep-phnucl-exnucl-thRMP(2022)·162 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.