Fri·May 15, 2020Friday·May 15, 2020

1. 01*

   Overview of heavy-flavour measurements in ALICE

   Lennart van Doremalen (for the ALICE Collaboration)🇳🇱

   ALICE is devoted to the study of the properties of the Quark-Gluon Plasma (QGP). This state of matter is created in ultra-relativistic heavy-ion collisions at the LHC. Heavy quarks are considered effective probes of the QGP since, due to their large masses, they are produced in hard scattering processes and experience the full evolution of the hot and dense medium while interacting with its constituents. The heavy-quark measurements provide insights on processes like in-medium energy loss and hadronization. Measurements in proton-proton collisions provide the baseline for interpreting heavy-ion collision results and constitute an excellent test of pQCD calculations. In addition, proton-nucleus collisions allow separating cold nuclear matter effects from those due to the deconfined strongly interacting matter created in heavy-ion collisions. In this contribution, an overview of recent ALICE results for open heavy flavours, quarkonia, and heavy-flavour jets is presented.

   nucl-exhep-exActa Phys.Polon.Supp.(2021)·2 citations
2. 02*

   Simultaneous muon and reference hadron measurements in the Compressed Baryonic Matter experiment at FAIR

   Anna Senger (for the CBM Collaboration)🇩🇪

   The mission of the Compressed Baryonic Matter (CBM) experiment at the future Facility for Antiproton and Ion Research (FAIR) in Darmstadt is to explore the QCD phase diagram at high net baryon densities likely to exist in the core of neutron stars. The CBM detector system is designed to perform multi-differential measurements of hadrons and leptons in central gold-gold collisions at beam energies between 2 and 11 A GeV with unprecedented precision and statistics. In order to reduce the systematic errors of the lepton measurements, which generally suffer from a large combinatorial background, both electrons and muons will be measured with the same acceptance. Up to now, no di-muon measurements have been performed in heavy-ion collisions at beam energies below 158A GeV. The main device for electron identification, a Ring Imaging Cherenkov (RICH) detector, can be replaced by a setup comprising hadron absorbers and tracking detectors for muon measurements. In order to obtain a complete picture of the reaction, it is important to measure simultaneously leptons and hadrons. This requirement is fulfilled for the RICH, which has a low material budget, and only little affects the trajectories of hadrons on their way to the Time-of-Flight (TOF) detector. In contrast, the simultaneous measurement of muons and hadrons within the same experimental acceptance poses a substantial challenge. This article reviews the simulated performance of the CBM experiment for muon identification, together with the possibility of simultaneous hadron measurements.

   nucl-exIJMPE(2020)·0 citations
3. 03*

   Highlights of the Spectroscopy of Hyperons and Cascade Baryons

   Annika Thiel🇩🇪 · Eberhard Klempt🇩🇪

   We highlight topical issues in hyperon spectroscopy that will be accessible when a secondary beam of neutral kaons is created in Hall D at Jefferson Lab as proposed to the JLab Program Advisory Committee. The new beam will have a flux of $10^4$ $K_L$/s. The reaction products will be analyzed in the GlueX experimental setup. We point out which physical questions need to be answered and suggest a number of novel experiments. In particular we suggest to measure the presently disputed SU(3) structure of the $\Lambda (1405)$, to search for Pentaquarks mit exotic quantum numbers and to search for baryons belonging to the SU(6) 20-plet representation.

   nucl-exnucl-th3 citations
4. 04*

   Growth and development of pure Li2MoO4 crystals for rare event experiment at CUP

   J. K. Son🇰🇷 · J. S. Choe🇰🇷 · O. Gileva🇰🇷 · I. S. Hahn🇰🇷 · W. G. Kang🇰🇷 · D. Y. Kim🇰🇷 · G. W. Kim🇰🇷 · H. J. Kim🇰🇷 · Y. D. Kim🇰🇷 · C. H. Lee🇰🇷 · E. K. Lee🇰🇷 · M. H. Lee🇰🇷 and 5 other authors

   The Center for Underground Physics (CUP) of the Institute for Basic Science (IBS) is searching for the neutrinoless double-beta decay (0{\nu}\b{eta}\b{eta}) of 100Mo in the molybdate crystals of the AMoRE experiment. The experiment requires pure scintillation crystals to minimize internal backgrounds that can affect the 0{\nu}\b{eta}\b{eta} signal. For the last few years, we have been growing and studying Li2MoO4 crystals in a clean-environment facility to minimize external contamination during the crystal growth. Before growing Li2100MoO4 crystal, we have studied Li2natMoO4 crystal growth by a conventional Czochralski (CZ) grower. We grew a few different kinds of Li2natMO4 crystals using different raw materials in a campaign to minimize impurities. We prepared the fused Al2O3 refractories for the growth of ingots. Purities of the grown crystals were measured with high purity germanium detectors and by inductively coupled plasma mass spectrometry. The results show that the Li2MoO4 crystal has purity levels suitable for rare-event experiments. In this study, we present the growth of Li2MoO4 crystals at CUP and their purities.

   ↳ physics.ins-detastro-ph.IMhep-exnucl-exJINST(2020)·9 citations
5. 05*

   Two-pole structures in QCD: Facts, not fantasy!

   Ulf-G. Meißner🇩🇪

   The two-pole structure refers to the fact that particular single states in the spectrum as listed in the PDG tables are often two states. The story began with the $\Lambda (1405)$, when in 2001, using unitarized chiral perturbation theory, it was observed that there are two poles in the complex plane, one close to the $\bar{K}p$ and the other close to the $\pi \Sigma$ threshold. This was later understood combining the SU(3) limit and group-theoretical arguments. Different unitarization approaches that all lead to the two-pole structure have been considered in the mean time, showing some spread in the pole positions. This fact is now part of the PDG book, though it is not yet listed in the summary tables. Here, I will discuss the open ends and critically review approaches that can not deal with this issue. In the meson sector some excited charm mesons are good candidates for such a two-pole structure. Next, I consider in detail the $D_0^{\ast }(2300)$, that is another candidate for this scenario. Combining lattice QCD with chiral unitary approaches in the finite volume, the precise data of the Hadron Spectrum Collaboration for coupled-channel $D\pi$, $D\eta$, $D_s\bar{K}$ scattering in the isospin $I=1/2$ channel indeed reveal its two-pole structure. Further states in the heavy meson sector with $I=1/2$ exhibiting this phenomenon are predicted, especially in the beauty meson sector. I also discuss the relation of these two-pole structures and the possible molecular nature of the states under consideration.

   ↳ hep-phhep-exhep-latnucl-ex+1Symmetry(2020)·119 citations
6. 06*

   $Z^0$ boson associated b-jet production in high-energy nuclear collisions

   Sa Wang🇨🇳 · Wei Dai🇨🇳 · Ben-Wei Zhang🇨🇳 · Enke Wang🇨🇳

   The production of vector boson tagged heavy quark jets potentially provides new tools to probe the jet quenching effect. In this paper, we present the first theoretical study on the angular correlations ($\Delta {\varphi }_{bZ}$), transverse momentum imbalance ($x_{bZ}$), and nuclear modification factor ($I_{AA}$) of $Z^0$ boson tagged b-jets in heavy-ion collisions, which was performed using a Monte Carlo transport model. We find that the medium modification of the $\Delta {\varphi }_{bZ}$ for $Z^0+$b-jet has a weaker dependence on $\Delta {\varphi }_{bZ}$ than that for $Z^0+$jet, and the modification patterns are sensitive to the initial jet $p_T$ distribution. Additionally, with the high purity of the quark jet in $Z^0+$(b-)jet production, we calculate the momentum imbalance $x_{bZ}$ and the nuclear modification factor $I_{AA}$ of $Z^0+$b-jet in Pb+Pb collisions. We observe a smaller $\Delta ⟨x_{jZ}⟩$ and larger $I_{AA}$ of $Z^0+$b-jet in Pb+Pb collisions relative to those of $Z^0+$jet, which may be an indication of the mass effect of jet quenching and can be tested in future measurements.

   ↳ hep-phnucl-exnucl-thCPC(2023)·19 citations
7. 07*

   Installation and Commissioning of the GlueX DIRC

   A. Ali🇩🇪 · F. Barbosa🇺🇸 · J. Bessuille🇺🇸 · E. Chudakov🇺🇸 · R. Dzhygadlo🇩🇪 · C. Fanelli🇺🇸 · J. Frye🇺🇸 · J. Hardin🇺🇸 · A. Hurley🇺🇸 · E. Ihloff🇺🇸 · G. Kalicy🇺🇸 · J. Kelsey🇺🇸 and 8 other authors

   The GlueX experiment takes place in experimental Hall D at Jefferson Lab (JLab). With a linearly polarized photon beam of up to 12 GeV energy, GlueX is a dedicated experiment to search for hybrid mesons via photoproduction reactions. The low-intensity (Phase I) of GlueX was recently completed; the high-intensity (Phase II) started in 2020 including an upgraded particle identification system, known as the DIRC (Detection of Internally Reflected Cherenkov light), utilizing components from the decommissioned BaBar experiment. The identification and separation of the kaon final states will significantly enhance the GlueX physics program, by adding the capability of accessing the strange quark flavor content of conventional (and potentially hybrid) mesons. In these proceedings, we report that the installation and commissioning of the DIRC detector has been successfully completed.

   ↳ physics.ins-detnucl-exJINST(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.