Fri·Oct 28, 2022Friday·October 28, 2022

1. 01*

   Search for the Chiral Magnetic Effect with charge-dependent azimuthal correlations in Xe-Xe collisions at $\sqrt{s_{\mathrm{NN}}}=5.44$ TeV

   ALICE Collaboration

   Charge-dependent two- and three-particle correlations measured in Xe-Xe collisions at $\sqrt{s_{\mathrm{NN}}}=5.44$ TeV are presented. Results are obtained for charged particles in the pseudorapidity range $|\eta |<0.8$ and transverse momentum interval $0.2\le p_{\mathrm{T}}<5.0$ GeV/$c$ for different collision centralities. The three-particle correlator ${\gamma }_{\alpha \beta }\equiv ⟨\cos ({\phi }_{\alpha }+{\phi }_{\beta }-2{\Psi }_2)⟩$, calculated for different combinations of charge sign $\alpha$ and $\beta$, is expected to be sensitive to the presence of the Chiral Magnetic Effect (CME). Its magnitude is similar to the one observed in Pb-Pb collisions in contrast to a smaller CME signal in Xe-Xe collisions than in Pb-Pb collisions predicted by Monte Carlo (MC) calculations including a magnetic field induced by the spectator protons. These observations point to a large non-CME contribution to the correlator. Furthermore, the charge dependence of ${\gamma }_{\alpha \beta }$ can be described by a blast wave model calculation that incorporates background effects and by the Anomalous Viscous Fluid Dynamics model with values of the CME signal consistent with zero. The Xe-Xe and Pb-Pb results are combined with the expected CME signal dependence on the system size from the MC calculations including a magnetic field to obtain the fraction of CME contribution in ${\gamma }_{\alpha \beta }$, $f_{\mathrm{CME}}$. The CME fraction is compatible with zero for the 30% most central events in both systems and then becomes positive. This yields an upper limit of 2% (3%) and 25% (32%) at 95% (99.7%) confidence level for the CME signal contribution to ${\gamma }_{\alpha \beta }$ in the 0-70% Xe-Xe and Pb-Pb collisions, respectively.

   nucl-exhep-exPLB(2024)·20 citations
2. 02*

   Development of a jet gas target system for the Felsenkeller underground accelerator

   Anup Yadav🇮🇳 · Konrad Schmidt🇩🇪 · Daniel Bemmerer🇩🇪

   For direct cross-section measurements in nuclear astrophysics, in addition to suitable ion beams and detectors, also highly pure and stable targets are needed. Here, using a gas jet as a target offers an attractive approach that combines high stability even under significant beam load with excellent purity and high localisation. Such a target is currently under construction at the Felsenkeller underground ion accelerator lab for nuclear astrophysics in Dresden, Germany. The target thickness will be measured by optical interferometry, allowing an in-situ thickness determination including also beam-induced effects. The contribution reports on the status of this new system and outlines possible applications in nuclear astrophysics.

   ↳ physics.ins-detnucl-exEPJ Web Conf.(2023)·4 citations
3. 03*

   Cumulants from short-range correlations and baryon number conservation - next-to-leading order

   Michał Barej🇵🇱 · Adam Bzdak🇵🇱

   We calculate the baryon number cumulants within acceptance with short-range correlations and global baryon number conservation in terms of cumulants in the whole system without baryon conservation. We extract leading and next-to-leading order terms of the large baryon number limit approximation. Our results extend the findings of Refs. [1,2]. These approximations are checked to be very close to the exact results.

   ↳ hep-phhep-exnucl-exnucl-thPRC(2023)·5 citations
4. 04*

   Large area photon calorimeter with Ir-Pt bilayer transition-edge sensor for the CUPID experiment

   V. Singh🇺🇸 · G. Benato🇮🇹 · M. Beretta🇺🇸 · C. Capelli🇺🇸 · C.L. Chang🇺🇸 · B.K. Fujikawa🇺🇸 · E.V. Hansen🇺🇸 · Yu.G. Kolomensky🇺🇸 · WK. Kwok🇺🇸 · M. Lisovenko🇺🇸 · L. Marini🇮🇹 · V. Novosad🇺🇸 and 8 other authors

   CUPID is a next-generation neutrinoless double-beta decay experiment that will require cryogenic light detectors to improve background suppression, via the simultaneous readout of heat and light channels from its scintillating crystals. In this work we showcase light detectors based on a novel Ir-Pt bilayer transition edge sensor. We have performed a systematic study to improve the thermal coupling between the photon absorber and the sensor, and thereby its responsivity. Our first devices meet CUPID's baseline noise requirement of <100~eV rms. Our detectors have risetimes of $\sim$180 $\mu$s and measured timing jitter of <20 $\mu$s for the expected signal-to-noise at the Q-value of the decay, which achieves the CUPID's criterion of rejecting two-neutrino double-beta decay pileup events. The current work will inform the fabrication of future devices, culminating in the final TES design and a scaleable readout scheme for CUPID.

   ↳ physics.ins-dethep-exnucl-exphysics.app-phPhys.Rev.Applied(2023)·15 citations
5. 05*

   Centrality dependence of proton and light nuclei yields as a consequence of baryon annihilation in the hadronic phase

   Volodymyr Vovchenko🇺🇸 · Volker Koch🇺🇸

   The centrality dependence of the $p/\pi$ ratio measured by the ALICE Collaboration in 5.02 TeV Pb-Pb collisions indicates a statistically significant suppression with the increase of the charged particle multiplicity once the centrality-correlated part of the systematic uncertainty is eliminated from the data. We argue that this behavior can be attributed to baryon annihilation in the hadronic phase. By implementing the $B\bar{B}\leftrightarrow 5\pi$ reaction within a generalized partial chemical equilibrium framework, we estimate the annihilation freeze-out temperature at different centralities, which decreases with increasing charged multiplicity and yields $T_{\mathrm{ann}}=132\pm 5$ MeV in 0-5% most central collisions. This value is considerably below the hadronization temperature of $T_{\mathrm{had}}\sim 160$ MeV but above the thermal (kinetic) freeze-out temperature of $T_{\mathrm{kin}}\sim 100$ MeV. Baryon annihilation reactions thus remain relevant in the initial stage of the hadronic phase but freeze out before (pseudo-)elastic hadronic scatterings. One experimentally testable consequence of this picture is a suppression of various light nuclei to proton ratios in central collisions of heavy ions.

   ↳ nucl-thhep-phnucl-exPLB(2022)·16 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.