Mon·Jan 13, 2020Monday·January 13, 2020

1. 01*

   Pseudorapidity dependence of anisotropic flow in heavy ion collisions with ALICE

   Freja Thoresen (ALICE Collaboration)🇩🇰

   The pseudorapidity dependence of flow coefficients, $v_n$, is presented over a large range in pseudorapidity ($-3.5\le \eta \le 5$) in Pb$-$Pb collisions at 5.02 TeV. The flow coefficients are measured with 2- and 4-particle cumulants with $|\Delta \eta |>0$ and $|\Delta \eta |>2$. The difference between $v_2\{2,|\Delta \eta |>0\}$ and $v_2\{2,|\Delta \eta |>2\}$ implies changes in either the de-correlation of flow vectors or non-flow effects between the two methods. The AMPT model shows a qualitative agreement with the measurements.

   nucl-ex0 citations
2. 02*

   Gamma-ray emission in alpha-particle reactions with C, Mg, Si, Fe

   J. Kiener · J. Bundesmann · I. Deloncle · A. Denker · V. Tatischeff · A. Gostojic · C. Hamadache · J. Röhrich · H. Benhabiles · I. Bougaoub · A. Coc · F. Hammache · J. Peyré

   Cross sections for the strongest gamma-ray emission lines produced in alpha-particle reactions with C, Mg, Si, Fe have been measured in the range E_alpha = 50 - 90 MeV at the center for proton therapy at the Helmholtz-Zentrum Berlin. Data for more than 60 different gamma-ray lines were determined, with particular efforts for lines that are in cross section compilations/evaluations with astrophysical purpose, and where data exist at lower projectile energies. The data are compared with predictions of a modern nuclear reaction code and cross-section curves of the latest evaluation for gamma-ray line emission in accelerated-particle interactions in solar flares.

   nucl-exastro-ph.HEJ.Phys.Conf.Ser.(2020)·0 citations
3. 03*

   Design and performance of a high-pressure xenon gas TPC as a prototype for a large-scale neutrinoless double-beta decay search

   S. Ban🇯🇵 · M. Hirose🇯🇵 · A. K. Ichikawa🇯🇵 · Y. Iwashita🇯🇵 · T. Kikawa🇯🇵 · A. Minamino🇯🇵 · K. Miuchi🇯🇵 · T. Nakadaira🇯🇵 · Y. Nakajima🇯🇵 · K. D. Nakamura🇯🇵 · K. Z. Nakamura🇯🇵 · T. Nakaya🇯🇵 and 7 other authors

   A high-pressure xenon gas time projection chamber, with a unique cellular readout structure based on electroluminescence, has been developed for a large-scale neutrinoless double-beta decay search. In order to evaluate the detector performance and validate its design, a 180~L size prototype is being constructed and its commissioning with partial detector has been performed. The obtained energy resolution at 4.0~bar is 1.73 $\pm$ 0.07% (FWHM) at 511 keV. The energy resolution at the ${}^{136}$Xe neutrinoless double-beta decay Q-value is estimated to be between 0.79 and 1.52% (FWHM) by extrapolation. Reconstructed event topologies show patterns peculiar to track end-point which can be used to distinguish $0\nu \beta \beta$ signals from gamma-ray backgrounds.

   ↳ physics.ins-dethep-exnucl-exPTEP(2020)·8 citations
4. 04*

   A Non-Equilibrium Approach to Photon Emission from the Late Stages of Relativistic Heavy-Ion Collisions

   Anna Schäfer🇩🇪 · Juan M. Torres-Rincon🇩🇪 · Charles Gale🇨🇦 · Hannah Elfner🇩🇪

   Cross sections for photon production in hadronic scattering processes have been calculated according to an effective chiral field theory. For $\pi +\rho \to \pi +\gamma$ and $\pi +\pi \to \rho +\gamma$ processes, these cross sections have been implemented into a novel hadronic transport approach (SMASH), which is suitable for collisions at low and intermediate energies. The implementation is verified by systematically comparing the thermal photon rate to theoretical expectations. The photon rates we obtain are compared to previous works, where scattering processes mediated by $\omega$ mesons are found to contribute significantly to the total photon production. Finally, the impact of considering the finite width of the $\rho$ meson is investigated, and a significant enhancement of photon production in the low-energy region is observed. This work is the first step towards a consistent treatment of photon emission in hybrid hydrodynamics+transport approaches. The quantification of the importance of the hadronic stage for the resolution of the direct photon flow puzzle is a next step and can be applied to identify equilibrium and non-equilibrium effects in the hadronic afterburner.

   ↳ nucl-thhep-phnucl-exNPA(2021)·5 citations
5. 05*

   The Mass of Short-Range Correlated Nucleon

   Rong Wang · Xurong Chen · Taofeng Wang

   The nucleon properties and structure should be modified by short-range correlations (SRC) among nucleons. By analyzing SRC ratio data, we extract the mass of nucleon in the SRC pair and the expected number of pn-SRC pairs in deuterium, under the assumption that the SRC nucleon mass is universal in different nuclei. The nucleon mass of a two-nucleon SRC pair is $m_{\text{SRC}}=852\pm 18$ MeV, and the number of pn-SRC pairs in deuterium is $n_{\text{SRC}}^{\text{d}}=0.021\pm 0.005$. The mass deficit of the strongly overlapping nucleon can be explained by the trace anomaly contribution to the mass in QCD or alternatively by the vacuum energy in the MIT bag model.

   ↳ nucl-thhep-phnucl-exCPC(2021)·6 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.