Wed·Sep 28, 2022Wednesday·September 28, 2022

1. 01*

   Estimate of a nonflow baseline for the chiral magnetic effect in isobar collisions at RHIC

   Yicheng Feng (for the STAR Collaboration)🇺🇸

   Recently, STAR reported the isobar (${}_{44}^{96}\text{Ru}+{}_{44}^{96}\text{Ru}$, ${}_{40}^{96}\text{Zr}+{}_{40}^{96}\text{Zr}$) results for the chiral magnetic effect (CME) search. The Ru+Ru to Zr+Zr ratio of the CME-sensitive observable $\Delta \gamma$, normalized by elliptic anisotropy ($v_2$), is observed to be close to the inverse multiplicity ($N$) ratio. In other words, the ratio of the $N\Delta \gamma /v_2$ observable is close to the naive background baseline of unity. However, nonflow correlations are expected to cause the baseline to deviate from unity. To further understand the isobar results, we decompose the nonflow contributions to $N\Delta \gamma /v_2$ (isobar ratio) into three terms and quantify each term by using the nonflow in $v_2$ measurement, published STAR data, and HIJING simulation. From these studies, we estimate a nonflow baseline of the isobar ratio of $N\Delta \gamma /v_2$ for the CME and discuss its implications.

   nucl-exEPJ Web Conf.(2023)·3 citations
2. 02*

   Determination of the titanium spectral function from (e,e'p) data

   L. Jiang🇺🇸 · A. M. Ankowski🇺🇸 · D. Abrams🇺🇸 · L. Gu🇺🇸 · B. Aljawrneh🇺🇸 · S. Alsalmi🇸🇦 · J. Bane🇺🇸 · A. Batz🇺🇸 · S. Barcus🇺🇸 · M. Barroso🇺🇸 · V. Bellini🇮🇹 · O. Benhar🇮🇹 and 53 other authors

   The E12-14-012 experiment, performed in Jefferson Lab Hall A, has measured the (e,e'p) cross section in parallel kinematics using a natural titanium target. Here, we report the full results of the analysis of the data set corresponding to beam energy 2.2 GeV, and spanning the missing momentum and missing energy range 15 <= pm <= 250 MeV/c and 12 <= Em <= 80 MeV. The reduced cross section has been measured with ~7% accuracy as function of both missing momentum and missing energy. We compared our data to the results of a Monte Carlo simulations performed using a model spectral function and including the effects of final state interactions. The overall agreement between data and simulations is quite good (chi2/d.o.f. = 0.9).

   nucl-exhep-exnucl-thPRD(2023)·30 citations
3. 03*

   Design and test results of scientific X-ray CMOS cameras

   Wenxin Wang · Zhixing Ling · Chen Zhang🇺🇸 · Qiong Wu · Zhenqing Jia🇨🇳 · Xinyang Wang · Weimin Yuan🇮🇹 · Shuang-Nan Zhang🇨🇳

   In recent years, scientific CMOS (sCMOS) sensors have found increasing applications to X-ray detection, including X-ray astronomical observations. In order to examine the performance of sCMOS sensors, we have developed X-ray cameras based on sCMOS sensors. Two cameras, CNX22 and CNX 66, have been developed using sCMOS sensors with a photosensitive area of 2 cm * 2 cm and 6 cm * 6 cm, respectively. The designs of the cameras are presented in this paper. The CNX22 camera has a frame rate of 48 fps, whereas CNX66 has a frame rate of currently 20 fps, that can be boosted to 100 fps in the future. The operating temperature of the sCMOS sensor can reach to -20C for CNX22 and -30C for CNX66 with a peltier cooler device. In addition to the commonly used mode of saving original images, the cameras provide a mode of real-time extraction of X-ray events and storage their information, which significantly reduces the requirement for data storage and offline analysis work. For both cameras, the energy resolutions can reach less than 200 eV at 5.9 keV using single-pixel events. These cameras are suitable for X-ray spectroscopy applications in laboratories and calibration for the space X-ray telescopes.

   ↳ astro-ph.IMhep-exnucl-exProc.SPIE Int.Soc.Opt.Eng.(2022)·8 citations
4. 04*

   Local position-space two-nucleon potentials from leading to fourth order of chiral effective field theory

   S. K. Saha🇮🇳 · D. R. Entem🇪🇸 · R. Machleidt🇺🇸 · Y. Nosyk🇺🇸

   We present local, position-space chiral NN potentials through four orders of chiral effective field theory ranging from leading order (LO) to next-to-next-to-next-to-leading order (N3LO, fourth order) of the Delta-less version of the theory. The long-range parts of these potentials are fixed by the very accurate pi-N LECs as determined in the Roy-Steiner equations analysis. At the highest order (N3LO), the NN data below 190 MeV laboratory energy are reproduced with the respectable chi^2/datum of 1.45. A comparison of the N3LO potential with the phenomenological Argonne v_18 (AV18) potential reveals substantial agreement between the two potentials in the intermediate range ruled by chiral symmetry, thus, providing a chiral underpinning for the phenomenological AV18 potential. Our chiral NN potentials may serve as a solid basis for systematic ab initio calculations of nuclear structure and reactions that allow for a comprehensive error analysis. In particular, the order by order development of the potentials will make possible a reliable determination of the truncation error at each order. Our new family of local position-space potentials differs from existing potentials of this kind by a weaker tensor force as reflected in relatively low D-state probabilities of the deuteron (P_D less or equal 4.0% for our N3LO potentials) and predictions for the triton binding energy above 8.00 MeV (from two-body forces alone). As a consequence, our potentials may lead to different predictions when applied to light and intermediate-mass nuclei in ab initio calculations and, potentially, help solve some of the outstanding problems in microscopic nuclear structure.

   ↳ nucl-thnucl-exPRC(2023)·29 citations
5. 05*

   Gamma and neutron separation using emission wavelengths in Eu:LiCaI scintillators

   Takashi Iida🇯🇵 · Masao Yoshino🇯🇵 · Kei Kamada🇯🇵 · Rei Sasaki · Ryuga Yajima

   Scintillators have long been known as radiation detectors and are still used in various applications. Recently, scintillators containing ${}^6$Li have been developed as neutron detectors and have attracted attention. ${}^6$Li absorbs thermal neutrons and emits $\alpha$+${}^3$H, which is promising as a neutron detector if it can be separated from background gamma rays. We have been developing Eu:LiI-CaI${}_2$-based scintillators (Eu:LiCaI) for this purpose. In scintillator detectors, waveform information is generally used to distinguish particles such as neutrons and gamma rays. We propose a new particle identification method using emission wavelengths information. In this study, experiments were conducted using Eu:LiCaI crystals, multi-pixel photon counter optical sensors, and long-wavelength cut filters to verify the proposed method. The results of irradiating a ${}^{252}$Cf neutron source and a ${}^{60}$Co gamma-ray source indicate that there is a particle dependence of the output signal ratio between with and without filters. This means that different types of radiation particles have different emission wavelengths. This is the first demonstration of a wavelength-based particle identification method.

   ↳ physics.ins-detnucl-exPTEP(2023)·0 citations
6. 06*

   Bottom hadro-chemistry in high-energy hadronic collisions

   Min He🇨🇳 · Ralf Rapp🇺🇸

   The hadro-chemistry of bottom quarks ($b$) produced in hadronic collisions encodes valuable information on the mechanism of color-neutralization in these reactions. Since the $b$-quark mass is much larger than the typical hadronic scale of $\sim$1\,GeV, $b\bar{b}$ pair production is expected to be well separated from subsequent hadronization processes. A significantly larger fraction of $b$ baryons has been observed in proton-proton ($pp$) and proton-antiproton ($p\bar{p}$) reactions relative to $e^{+}{e}^{-}$ collisions, challenging theoretical descriptions. We address this problem by employing a statistical hadronization approach with an augmented set of $b$-hadron states beyond currently measured ones, guided by the relativistic quark model and lattice-QCD computations. Assuming {\it relative} chemical equilibrium between different $b$-hadron yields, thermal densities are used as fragmentation weights of $b$-quarks into various hadron species. With quark model estimates of the decay patterns of excited states, the fragmentation fractions of weakly-decaying $b$ hadrons are computed and found to agree with measurements in $p\bar{p}$ collisions at the Tevatron. By combining transverse-momentum ($p_T$) distributions of $b$-quarks from perturbative QCD with thermal weights and independent fragmentation toward high $p_T$, a fair description of the $p_T$-dependent ${\bar{B}}_s^0/B^{-}$ and ${\Lambda }_b^0/B^{-}$ ratios measured in $pp$ collisions at the LHC is obtained. Finally, we implement the hadro-chemistry into a strongly-coupled transport approach for $b$-quarks in heavy-ion collisions, utilizing previously determined $b$-quark transport coefficients in the Quark-Gluon Plasma, to highlight the modifications of hadro-chemistry and collective behavior of $b$ hadrons in Pb-Pb collisions at the LHC.

   ↳ hep-phhep-exnucl-exnucl-thPRL(2023)·32 citations
7. 07*

   Medium-enhanced $c\bar{c}$ radiation

   Maximilian Attems · Jasmine Brewer · Gian Michele Innocenti · Aleksas Mazeliauskas · Sohyun Park · Wilke van der Schee · Urs Wiedemann

   We show that the same QCD formalism that accounts for the suppression of high-$p_T$ hadron and jet spectra in heavy-ion collisions predicts medium-enhanced production of $c\bar{c}$ pairs in jets.

   ↳ hep-phnucl-exnucl-thPRL(2024)·22 citations
8. 08*

   A method for computing hadron-nucleus cross sections in fully active sampling calorimetric targets

   Johnny Ho🇺🇸 · David W. Schmitz🇺🇸

   Interaction cross section measurements in fixed-target scattering experiments are typically performed by measuring the attenuation of a beam of particles that is incident upon a target slab of material. A fully active sampling calorimeter, such as the time projection chamber, is a more voluminous target that can be treated as a series of smaller target slabs. We present a method of computing hadron-nucleus interaction cross sections for data taken with fully active sampling calorimeters that is robust even if the target is comprised of numerous slabs of various thicknesses.

   ↳ physics.ins-dethep-exnucl-ex0 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.