Wed·Mar 4, 2020Wednesday·March 4, 2020

1. 01*

   Momentum-dependent flow fluctuations as a hydrodynamic response to initial geometry

   Maurício Hippert🇧🇷 · David Dobrigkeit Chinellato🇧🇷 · Matthew Luzum🇧🇷 · Jorge Noronha🇺🇸 · Tiago Nunes da Silva🇧🇷 · Jun Takahashi🇧🇷

   We propose a redefinition of the principal component analysis (PCA) of anisotropic flow that makes it more directly connected to fluctuations of the initial geometry of the system. Then, using state-of-the-art hydrodynamic simulations, we make an explicit connection between flow fluctuations and a cumulant expansion of the initial transverse geometry. In particular, we show that the second principal component of elliptic flow is generated by higher-order cumulants, and therefore probes smaller length scales of the initial state. With this information, it will be possible to put new constraints on properties of the early-time dynamics of a heavy-ion collision, including small-scale structure, as well as properties of the quark-gluon plasma.

   ↳ nucl-thnucl-exNPA(2021)·3 citations
2. 02*

   Performance recovery of long CsI(Tl) scintillator crystals with APD-based readout

   P. Cabanelas🇪🇸 · D. González🇪🇸 · H. Alvarez-Pol🇪🇸 · J.M. Boillos🇪🇸 · E. Casarejos🇪🇸 · J. Cederkall🇸🇪 · D. Cortina🇪🇸 · M. Feijoo🇪🇸 · D. Galaviz🇵🇹 · E. Galiana🇪🇸 · R. Gernhäuser🇩🇪 · P. Golubev🇸🇪 and 14 other authors

   CALIFA is the high efficiency and energy resolution calorimeter for the R3B experiment at FAIR, intended for detecting high energy light charged particles and gamma rays in scattering experiments, and is being commissioned during the Phase-0 experiments at FAIR, between 2018 and 2020. It surrounds the reaction target in a segmented configuration with 2432 detection units made of long CsI(Tl) finger-shaped scintillator crystals. CALIFA has a 10 year intended operational lifetime as the R3B calorimeter, necessitating measures to be taken to ensure enduring performance. In this paper we present a systematic study of two groups of 6 different detection units of the CALIFA detector after more than four years of operation. The energy resolution and light output yield are evaluated under different conditions. Tests cover the aging of the first detector units assembled and investigates recovery procedures for degraded detection units. A possible reason for the observed degradation is given, pointing to the crystal-APD coupling.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2020)·4 citations
3. 03*

   Nuclear system size scan for freeze-out properties in relativistic heavy-ion collisions by using a multiphase transport model

   Dong-Fang Wang🇨🇳 · Song Zhang🇨🇳 · Yu-Gang Ma🇨🇳

   A system size scan program was recently proposed for the STAR experiments at the Relativistic Heavy Ion Collider(RHIC). In this study, we employ a multiphase transport (AMPT) model for considering the bulk properties at the freeze-out stage for ${}^{10}\mathrm{B}{+}^{10}\mathrm{B}$, ${}^{12}\mathrm{C}{+}^{12}\mathrm{C}$, ${}^{16}\mathrm{O}{+}^{16}\mathrm{O}$, ${}^{20}\mathrm{Ne}{+}^{20}\mathrm{Ne}$, ${}^{40}\mathrm{Ca}{+}^{40}\mathrm{Ca}$, ${}^{96}\mathrm{Zr}{+}^{96}\mathrm{Zr}$, and ${}^{197}\mathrm{Au}{+}^{197}\mathrm{Au}$ collisions at RHIC energies $\sqrt{s_{NN}}$ of 200, 20, and 7.7 GeV. The results for ${}^{197}\mathrm{Au}{+}^{197}\mathrm{Au}$ collisions are comparable with those of previous experimental STAR data. The transverse momentum $p_T$ spectra of charged particles (${\pi }^{\pm }$, $K^{\pm }$, $p$, and $\bar{p}$) at the kinetic freeze-out stage, based on a blast-wave model, are also discussed. In addition, we use a statistical thermal model to extract the parameters at the chemical freeze-out stage, which agree with those from other thermal model calculations. It was found that there is a competitive relationship between the kinetic freeze-out parameter $T_{kin}$ and the radial expansion velocity ${\beta }_T$, which also agrees with the STAR or ALICE results. We found that the chemical freeze-out strangeness potential ${\mu }_s$ remains constant in all collision systems and that the fireball radius $R$ is dominated by $⟨{\mathrm{N}}_{\mathrm{Part}}⟩$, which can be well fitted by a function of $a{⟨{\mathrm{N}}_{\mathrm{Part}}⟩}^b$ with $b\approx 1/3$. In addition, we calculated the nuclear modification factors for different collision systems with respect to the ${}^{10}\mathrm{B}+{}^{10}\mathrm{B}$ system, and found that they present a gradual suppression within a higher $p_T$ range from small to large systems.

   ↳ hep-phnucl-exnucl-thPRC(2020)·9 citations
4. 04*

   The first dual-phase xenon TPC equipped with silicon photomultipliers and characterisation with ${}^{37}$Ar

   L. Baudis🇨🇭 · Y. Biondi🇨🇭 · M. Galloway🇨🇭 · F. Girard🇨🇭 · S. Hochrein🇨🇭 · S. Reichard🇨🇭 · P. Sanchez-Lucas🇨🇭 · K. Thieme🇨🇭 · J. Wulf🇨🇭

   For the first time, a small dual-phase (liquid/gas) xenon time projection chamber was equipped with a top array of silicon photomultipliers for light and charge readout. Here we describe the instrument in detail, as well as the data processing and the event position reconstruction algorithms. We obtain a spatial resolution of ~1.5 mm in the horizontal plane. To characterise the detector performance, we show calibration data with internal ${}^{83\text{m}}$Kr and ${}^{37}$Ar sources, and we detail the production of the latter as well as its introduction into the system. We finally compare the observed light and charge yields down to electronic recoil energies of 2.82 keV to predictions based on NEST v2.0.

   ↳ astro-ph.IMhep-exnucl-exphysics.ins-detEPJC(2020)·24 citations
5. 05*

   Digitized Waveform Signal Processing for Fast Timing: An Application to SiPM Timing in the Presence of Dark Count Noise

   Sebastian White🇨🇭 · Arjan Heering🇺🇸

   In this paper we illustrate techniques for digitized waveform signal processing of fast timing detectors. In the example discussed here, timing analysis of SiPM signals in the presence of high Dark Count Rates, a large data set of digitized waveforms is used to develop an optimal strategy relevant to the electronics front end design.

   ↳ physics.ins-dethep-exnucl-exJINST(2020)·1 citation

* 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.