Mon·Oct 25, 2021Monday·October 25, 2021

1. 01*

   Jet substructure measurements with ALICE

   Robert Vertesi (for the ALICE Collaboration)🇭🇺

   A selection of new jet substructure measurements are reported from the ALICE experiment at the CERN LHC in both proton-proton and heavy-ion collisions. These include the first fully corrected inclusive measurements of the groomed jet momentum fraction and the groomed jet radius, as well as the $N$-subjettiness distribution and the fragmentation distribution of reclustered subjets. We also report on the measurement of several groomed substructure observables of heavy-flavor jets in pp collisions, fragmentation functions and the new measurements of the radial distributions of D${}^0$ mesons or ${\Lambda }_c^{+}$ baryons in jets. The measurements are compared to theoretical calculations and provide new constraints on the physics underlying parton fragmentation and jet quenching.

   nucl-exhep-exPhys.Part.Nucl.(2023)·2 citations
2. 02*

   Cumulants: It's More Than You Think

   Agnieszka Sorensen🇺🇸 · Dmytro Oliinychenko🇺🇸 · Volker Koch🇺🇸 · Larry McLerran🇺🇸

   Cumulants of baryon number are given considerable attention in analyses of heavy-ion collision experiments as possible signatures of the QCD critical point. In this work, we show that the values of the lowest three cumulants can also be utilized to recover information about the isothermal speed of sound and its logarithmic derivative with respect to the baryon number density. This result provides a new method for obtaining information about fundamental properties of nuclear matter studied in heavy-ion collisions, with consequences for both the search for the QCD critical point and neutron star studies. While the approximations and the model comparison we considered apply to experiments at low energies, the approach itself can be used at any collision energy provided that measurements of cumulants of baryon number distribution as well as their temperature dependence are available.

   ↳ nucl-thnucl-exPoS(2022)·0 citations
3. 03*

   The new MRTOF mass spectrograph following the ZeroDegree spectrometer at RIKEN's RIBF facility

   M. Rosenbusch🇩🇪 · M. Wada · S. Chen🇯🇵 · A. Takamine · S. Iimura · D. Hou · W. Xian · S. Yan · P. Schury🇯🇵 · Y. Hirayama · Y. Ito🇯🇵 · H. Ishiyama and 14 other authors

   A newly assembled multi-reflection time-of-flight mass spectrograph (MRTOF-MS) at RIKEN's RIBF facility became operational for the first time in spring 2020; further modifications and performance tests using stable ions were completed in early 2021. By using a pulsed-drift-tube technique to modify the ions' kinetic energy in a wide range, we directly characterize the dispersion function of the system for use in a new procedure for optimizing the voltages applied to the electrostatic mirrors. Thus far, a mass resolving power of $R_m>1000000$ is reached within a total time-of-flight of only $12.5\mathrm{ms}$, making the spectrometer capable of studying short-lived nuclei possessing low-lying isomers. Detailed information about the setup and measurement procedure is reported, and an alternative in-MRTOF ion selection scheme to remove molecular contaminants in the absence of a dedicated deflection device is introduced. The setup underwent an initial on-line commissioning at the BigRIPS facility at the end of 2020, where more than 70 nuclear masses have been measured. A summary of the commissioning experiments and results from a test of mass accuracy will be presented.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2023)·28 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.