Tue·Dec 18, 2018Tuesday·December 18, 2018

1. 01*

   Measurement of D-meson nuclear modification factor and flow in Pb--Pb collisions with ALICE at the LHC

   Fabrizio Grosa (for the ALICE Collaboration)🇮🇹

   Heavy quarks are sensitive probes of the colour-deconfined medium formed in ultra-relativistic heavy-ion collisions, the Quark-Gluon Plasma (QGP). The ALICE Collaboration measured the production of ${\mathrm{D}}^0$, ${\mathrm{D}}^{+}$, ${\mathrm{D}}^{\ast +}$ and ${{\mathrm{D}}_{\mathrm{s}}}^{+}$ mesons in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02\mathrm{TeV}$. The properties of the in-medium energy loss and the possible modification of the charm-quark hadronisation mechanism are investigated via the measurement of the nuclear modification factor ($R_{\mathrm{AA}}$) of non-strange and strange D mesons. In mid-central collisions, the measurement of the D-meson elliptic flow ($v_2$) at low and intermediate transverse momentum ($p_{\mathrm{T}}$) gives insight into the participation of the charm quark in the collective motion of the system, while at high $p_{\mathrm{T}}$ it constrains the path-length dependence of the energy loss. The coupling of the charm quark to the light quarks in the underlying medium is further investigated with the application of the event-shape engineering (ESE) technique to D-meson elliptic flow. Finally, the role of the early magnetic field created in heavy-ion collisions is studied via the first measurement at the LHC energies of the charged-dependent directed flow ($v_1$) of ${\mathrm{D}}^0$ mesons as a function of pseudorapidity.

   nucl-exPoS(2018)·4 citations
2. 02*

   Studies of Heavy Flavor Jets Using $D^0$-hadron Correlations in Azimuth and Pseudorapidity in Au+Au Collisions at 200 GeV at the STAR Experiment

   Alexander M. Jentsch🇺🇸

   Heavy flavor (HF) quarks (charm, bottom) are important probes of the medium produced in relativistic heavy-ion collisions because they are formed in the early stage and propagate throughout the lifetime of the QGP medium. HF-meson spectra and azimuthal anisotropy ($v_2$) measurements have been reported by experiments at RHIC and the LHC, and they suggest strong interactions of HF quarks with the medium. $D^0$-hadron correlations on relative pseudorapidity and azimuth ($\Delta \eta ,\Delta \varphi$) provide a method for disentangling correlation structures on ($\Delta \eta ,\Delta \varphi$), related to jets and bulk phenomena directly, with the $D^0$ serving as a proxy for a charm jet. In these proceedings, we present 2D $D^0$-hadron angular correlations as a function of centrality in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV. These data reveal a jet-like, peaked structure at ($\Delta \eta ,\Delta \varphi$) = (0, 0) (near-side), and a $\Delta \eta$-independent azimuthal harmonic modulation. Here, we focus on the evolution of the near-side peak's yield and widths on ($\Delta \eta ,\Delta \varphi$) as a function of centrality and compare them to results from light flavor correlations with a similar trigger mean-$p_T$.

   nucl-exPoS(2018)·0 citations
3. 03*

   Mechanical properties of particles

   Maxim V. Polyakov🇷🇺 · Peter Schweitzer🇺🇸

   Selected topics related to the physics of the energy-momentum tensor (EMT) form factors are discussed. The topics are: 1) Fundamental mechanical properties of particles and gravity 2) Mechanical properties of non-spherical particles 3) Gravitational form factors of Goldstone bosons 4) Nucleon's seismology?

   ↳ hep-phhep-exnucl-exPoS(2019)·32 citations
4. 04*

   Jet substructure modification in a QGP from a multi-scale description of jet evolution with JETSCAPE

   Y. Tachibana🇺🇸 · A. Angerami🇺🇸 · S. A. Bass🇺🇸 · S. Cao · J. Coleman🇬🇧 · L. Cunqueiro🇺🇸 · T. Dai🇺🇸 · L. Du🇺🇸 · H. Elfner🇩🇪 · D. Everett🇺🇸 · W. Fan🇺🇸 · R. Fries🇺🇸 and 32 other authors

   The modification of jet substructure in relativistic heavy-ion collisions is studied using JETSCAPE, a publicly available software package containing a framework for Monte Carlo event generators. Multi-stage jet evolution in JETSCAPE provides an integrated description of jet quenching by combining multiple models, with each becoming active at a different stage of the parton shower evolution. Jet substructure modification due to different aspects of jet quenching is studied using jet shape and jet fragmentation observables. Various combinations of jet energy loss models are exploed, with medium background provided by (2 + 1)-D VISHNU with TRENTo+freestreaming initial conditions. Results reported here are from simulations performed within JETSCAPE framework.

   ↳ nucl-thhep-phnucl-exPoS(2018)·17 citations
5. 05*

   Future physics opportunities for high-density QCD at the LHC with heavy-ion and proton beams

   Z. Citron🇮🇱 · A. Dainese🇮🇹 · J.F. Grosse-Oetringhaus🇨🇭 · J.M. Jowett🇨🇭 · Y.-J. Lee🇺🇸 · U.A. Wiedemann🇨🇭 · M. Winn (editors)🇫🇷 · A. Andronic🇩🇪 · F. Bellini🇨🇭 · E. Bruna🇮🇹 · E. Chapon🇨🇭 · H. Dembinski🇩🇪 and 173 other authors

   The future opportunities for high-density QCD studies with ion and proton beams at the LHC are presented. Four major scientific goals are identified: the characterisation of the macroscopic long wavelength Quark-Gluon Plasma (QGP) properties with unprecedented precision, the investigation of the microscopic parton dynamics underlying QGP properties, the development of a unified picture of particle production and QCD dynamics from small (pp) to large (nucleus--nucleus) systems, the exploration of parton densities in nuclei in a broad ($x$, $Q^2$) kinematic range and the search for the possible onset of parton saturation. In order to address these scientific goals, high-luminosity Pb-Pb and p-Pb programmes are considered as priorities for Runs 3 and 4, complemented by high-multiplicity studies in pp collisions and a short run with oxygen ions. High-luminosity runs with intermediate-mass nuclei, for example Ar or Kr, are considered as an appealing case for extending the heavy-ion programme at the LHC beyond Run 4. The potential of the High-Energy LHC to probe QCD matter with newly-available observables, at twice larger center-of-mass energies than the LHC, is investigated.

   ↳ hep-phhep-exnucl-exnucl-thCERN Yellow Rep.Monogr.(2019)·426 citations
6. 06*

   Using world charged pion--nucleus scattering data to constrain an intranuclear cascade model

   E. S. Pinzon Guerra🇨🇦 · C. Wilkinson🇨🇭 · S. Bhadra🇨🇦 · S. Bolognesi🇫🇷 · J. Calcutt🇺🇸 · P. de Perio🇨🇦 · S. Dolan🇫🇷 · T. Feusels🇨🇦 · G.A. Fiorentini🇨🇦 · Y. Hayato🇯🇵 · K. Ieki🇯🇵 · K. Mahn🇺🇸 and 10 other authors

   The NEUT intranuclear cascade model is described and fit to a large body of \pipm--nucleus scattering data. Methods are developed to deal with deficiencies in the available historical data, and robust uncertainty estimates are produced. The results are compared to a variety of simulation packages, and the data itself. This work provides a method for tuning Final State Interaction models, which are of particular interest to neutrino experiments that operate in the few-GeV energy region, and provides results which can be used directly by the T2K and Super-Kamiokande collaborations, for whom NEUT is the primary simulation package.

   ↳ hep-exnucl-exnucl-thPRD(2019)·78 citations
7. 07*

   The Hybrid MPGD-based photon detectors of COMPASS RICH-1

   J.Agarwala · M.Alexeev · C.D.R.Azevedo · F.Bradamante · A.Bressan · M.Buechele · C.Chatterjee · M.Chiosso · A.Cicuttin · P.Ciliberti · M.L.Crespo · S.Dalla Torre🇮🇹 and 19 other authors

   Novel gaseous detectors of single photons for RICH applications have been developed and installed on COMPASS RICH-1 in 2016. They have a hybrid architecture consisting of two staggered THGEM layers (one equipped with a CsI photoconverting layer) and a bulk Micromegas; they cover a total area of 1.4 squared meters and operate stably and efficiently. They provide a single photon angular resolution of ~ 1.8 mrad and about 10 detected photons per ring at saturation. The main aspects of their construction and commissioning, their characterization and performance figures are presented.

   ↳ physics.ins-dethep-exnucl-exNucl.Instrum.Meth.A(2020)·9 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.