Mon·May 3, 2021Monday·May 3, 2021

1. 01*

   Centrality dependence of electroweak boson production in PbPb collisions at the LHC

   Florian Jonas (Münster Uni.+ORNL)🇩🇪 · Constantin Loizides (ORNL)🇺🇸

   Recent data on the nuclear modification of W and Z boson production measured by the ATLAS collaboration in PbPb collisions at $\sqrt{s_{\mathrm{nn}}}=5.02$ TeV show an enhancement in peripheral collisions, seemingly contradicting predictions of the Glauber model. The data were previously explained by arguing that the nucleon-nucleon cross section may be shadowed in nucleus-nucleus collisions, and hence suppressed compared to the proton-proton cross section at the same collision energy. This interpretation has quite significant consequences for the understanding of heavy-ion data, in particular in the context of the Glauber model. Instead, we provide an alternative explanation of the data by assuming that there is a mild bias present in the centrality determination of the measurement; on the size of the related systematic uncertainty. Using this assumption, we show that the data is in agreement with theoretical calculations using nuclear parton distribution functions. Finally, we speculate that the centrality dependence of the W${}^{-}$/W${}^{+}$ ratio may point to the relevance of a larger skin thickness of the Pb nucleus, which, if present, would result in a few percent larger PbPb cross section than currently accounted for in the Glauber model and may hence be the root of the centrality bias.

   nucl-exhep-phnucl-thPRC(2021)·15 citations
2. 02*

   From Elastic Scattering to Central Exclusive Production: Physics with Forward Protons at RHIC

   Wlodek Guryn🇺🇸

   We describe a physics program at the Relativistic Heavy Ion Collider (RHIC) with tagged forward protons. The program started with the proton-proton elastic scattering experiment (PP2PP), for which a set of Roman Pot stations was build. The PP2PP experiment took data at RHIC as a dedicated experiment at the beginning of RHIC operations. To expand the physics program to include non-elastic channels with forward protons, like Central Exclusive Production (CEP), Central Production (CP) and Single Diffraction Dissociation (SD), the experiment with its equipment was merged with the STAR experiment at RHIC. Consequently the expanded program, which included both elastic and inelastic channels became part of the physics program and operations of the STAR experiment. In this paper we shall describe the physics results obtained by the PP2PP and STAR experiments to date.

   nucl-exhep-exActa Phys.Polon.B(2021)·2 citations
3. 03*

   Single photoelectron identification with Incom LAPPD 38

   S.P. Malace🇺🇸 · S. Wood🇺🇸

   Incom Inc. Large Area Picosecond Photodetector (LAPPD) 38 has been tested at Jefferson Lab to identify single-photoelectron signals to assess the potential of this type of device for future applications in Cherenkov light detection. Single-photoelectron signals were clearly detected if a tight collimation of photons impinging on the photocathode was used compared to the pixelation of the charge collection signal board.

   ↳ physics.ins-detnucl-exJINST(2021)·3 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.