Thu·Aug 6, 2020Thursday·August 6, 2020

1. 01*

   Strangeness photoproduction at the BGO-OD experiment

   Georg Scheluchin🇩🇪 · Stefan Alef🇩🇪 · Patrick Bauer🇩🇪 · Reinhard Beck🇩🇪 · Alessandro Braghieri🇮🇹 · Philip Cole🇺🇸 · Rachele Di Salvo🇮🇹 · Daniel Elsner🇩🇪 · Alessia Fantini🇮🇹 · Oliver Freyermuth🇩🇪 · Francesco Ghio🇮🇹 · Anatoly Gridnev🇷🇺 and 21 other authors

   The BGO-OD experiment at the University of Bonn's ELSA accelerator facility in Germany is ideally suited to investigate photoproduction at extreme forward angles. It combines a highly segmented BGO electromagnetic calorimeter at central angles and an open dipole magnetic spectrometer in the forward direction. This allows the detection of forward going kaons, and complex final states of mixed charge from hyperon decays. Current projects at the BGO-OD experiment include strangeness production of $\gamma p\to K^{+}\Lambda /{\Sigma }^0$ at forward angles, $K^0{\Sigma }^0$ with a deuteron target and $K^{+}\Lambda (1405)$ line shape and cross section measurements.

   nucl-ex0 citations
2. 02*

   Light neutral meson production in heavy ion collisions with ALICE in the era of precision physics at the LHC

   Mike Sas (for the ALICE collaboration)🇳🇱

   The production of light neutral mesons in AA collisions probes the physics of the Quark-Gluon Plasma (QGP), which is formed in heavy-ion collisions at the LHC. More specifically, the centrality dependent neutral meson spectra in AA collisions compared to its spectra in minimum-bias pp collisions, scaled with the number of hard collisions, provides information on the energy loss of partons traversing the QGP. The measurement allows to test with high precision the predictions of theoretical model calculations. In addition, the decay of the ${\pi }^0$ and $\eta$ mesons are the dominant backgrounds for all direct photon measurements. Therefore, pushing the limits of the precision of neutral meson production is key to learning about the temperature and space-time evolution of the QGP. In the ALICE experiment neutral mesons can be detected via their decay into two photons. The latter can be reconstructed using the two calorimeters EMCal and PHOS or via conversions in the detector material. The excellent momentum resolution of the conversion photons down to very low $p_{\mathrm{T}}$ and the high reconstruction efficiency and triggering capability of calorimeters at high $p_{\mathrm{T}}$, allow us to measure the $p_{\mathrm{T}}$ dependent invariant yield of light neutral mesons over a wide kinematic range. Combining state-of-the-art reconstruction techniques with the high statistics delivered by the LHC in Run 2 gives us the opportunity to enhance the precision of our measurements. In these proceedings, new ALICE run 2 preliminary results for neutral meson production in pp and Pb--Pb collisions at LHC energies are presented.

   nucl-exNPA(2021)·4 citations
3. 03*

   Light neutral meson production in the era of precision physics at the LHC

   Mike Sas (for the ALICE collaboration)🇳🇱

   The production of light neutral mesons in different collision systems is interesting for a variety of reasons: In nucleus-nucleus (AA) collisions the measurements provide important information on the energy loss of partons traversing the Quark-Gluon Plasma (QGP) which is formed in heavy-ion collisions at the LHC. In proton--proton (pp) collisions, neutral mesons allow us to test with high precision the predictions of perturbative QCD and other model calculations, and also serve as a reference for pA and AA collisions. In pA collisions, cold nuclear matter effects are studied. In the ALICE experiment, which is dedicated to the study of the QGP, neutral mesons can be detected via their decay to two photons. The latter can be reconstructed using the two calorimeters EMCal and PHOS or via conversions in the detector material. Combining state-of-the-art reconstruction techniques with the large data sample delivered by the LHC in Run 2 gives us the opportunity to enhance the precision of our measurements. In these proceedings, an overview of neutral meson production in pp, p--Pb and Pb--Pb collisions at LHC energies, as measured with the ALICE detector is presented.

   nucl-ex0 citations
4. 04*

   The ${}^{29}$F nucleus as a lighthouse on the coast of the island of inversion

   L. Fortunato🇮🇹 · J. Casal🇮🇹 · W. Horiuchi🇯🇵 · Jagjit Singh🇯🇵 · A. Vitturi🇮🇹

   The exotic, neutron-rich and weakly-bound isotope ${}^{29}$F stands out as a waymarker on the southern shore of the island of inversion, a portion of the nuclear chart where the effects of nuclear forces lead to a reshuffling of the single particle levels and to a reorganization of the nuclear structure far from stability. This nucleus has become very popular, as new measurements allow to refine theoretical models. We review the latest developments and suggest how to further assess the structure by proposing predictions on electromagnetic transitions that new experiments of Relativistic Coulomb Excitation should soon become able to measure.

   ↳ nucl-thnucl-exCommun.Phys.(2020)·24 citations
5. 05*

   Connecting spatial moments and momentum densities

   M. Hoballah🇫🇷 · M.B. Barbaro🇮🇹 · R. Kunne.🇫🇷 · M. Lassaut.🇫🇷 · D. Marchand🇫🇷 · G. Quéméner🇫🇷 · E. Voutier🇫🇷 · J. van de Wiele🇫🇷

   The precision of experimental data and analysis techniques is a key feature of any discovery attempt. A striking example is the proton radius puzzle where the accuracy of the spectroscopy of muonic atoms challenges traditional electron scattering measurements. The present work proposes a novel method for the determination of spatial moments from densities expressed in the momentum space. This method provides a direct access to even, odd, and more generally any real, negative and positive moment with order larger than $-3$. As an illustration, the application of this method to the electric form factor of the proton is discussed in detail.

   ↳ nucl-thnucl-exPLB(2020)·5 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.