Wed·Nov 22, 2023Wednesday·November 22, 2023

1. 01*

   Novel Cross Section Ratios as Possible Signals of Saturation in UPCs

   Yuri V. Kovchegov🇺🇸 · Huachen Sun🇺🇸 · Zhoudunming Tu🇺🇸

   We propose new cross section ratios in ultra-peripheral A$+$A and $p+$A collisions (UPCs) as a potential experimental signal of saturation physics. We consider the ratio $R_1$ of elastic vector meson photoproduction cross section to the inclusive hadron or jet photoproduction cross section. The ratio can be measured in the $\gamma +$A and $\gamma +p$ collisions taking place in the UPCs. We label the ratios $R_1(\mathrm{A})$ and $R_1(p)$, respectively. Constructing the double ratio $R_{\mathrm{UPC}}(\mathrm{A})=R_1(\mathrm{A})/R_1(p)$, and performing a small-$x$ calculation both in the quasi-classical approximation and by including small-$x$ evolution, we observe that $R_{\mathrm{UPC}}(\mathrm{A})$ exhibits a markedly different dependence on the nuclear atomic number inside and outside the saturation region. This result indicates that $R_{\mathrm{UPC}}(\mathrm{A})$ and $R_1(\mathrm{A})$ measurements in UPCs may help in the experimental searches for the evidence of saturation physics.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2024)·11 citations
2. 02*

   The Data Acquisition System for Phase-III of the BeEST Experiment

   C. Bray🇺🇸 · S. Fretwell🇺🇸 · I. Kim🇺🇸 · W. K. Warburton🇺🇸 · F. Ponce🇺🇸 · K. G. Leach🇺🇸 · S. Friedrich🇺🇸 · R. Abells🇨🇦 · P. Amaro🇵🇹 · A. Andoche🇫🇷 · R. Cantor🇺🇸 · D. Diercks🇺🇸 and 18 other authors

   The BeEST experiment is a precision laboratory search for physics beyond the standard model that measures the electron capture decay of ${}^7$Be implanted into superconducting tunnel junction (STJ) detectors. For Phase-III of the experiment, we constructed a continuously sampling data acquisition system to extract pulse shape and timing information from 16 STJ pixels offline. Four additional pixels are read out with a fast list-mode digitizer, and one with a nuclear MCA already used in the earlier limit-setting phases of the experiment. We present the performance of the data acquisition system and discuss the relative advantages of the different digitizers.

   ↳ physics.ins-detnucl-exquant-phJ.Low Temp.Phys.(2025)·4 citations
3. 03*

   A Comprehensive Characterization of the Neutron Fields Produced by the Apollon Petawatt Laser

   Ronan Lelièvre · Weipeng Yao · Tessa Waltenspiel · Itamar Cohen · Arie Beck · Erez Cohen · David Michaeli · Ishay Pomerantz · Donald Cort Gautier · François Trompier · Quentin Ducasse · Pavlos Koseoglou and 4 other authors

   Since two decades, laser-driven neutron emissions are studied as they represent a complementary source to conventional neutron sources, with further more different characteristics (i.e. shorter bunch duration and higher number of neutrons per bunch). We report here a global, thorough characterization of the neutron fields produced at the Apollon laser facility using the secondary laser beam (F2). A Double Plasma Mirror (DPM) was used to improve the temporal contrast of the laser which delivers pulses of 24 fs duration, a mean on-target energy of ~10 J and up to 1 shot/min. The interaction of the laser with thin targets (few tens or hundreds of nm) in ultra-high conditions produced enhanced proton beams (up to 35 MeV), which were then used to generate neutrons via the pitcher-catcher technique. The characterization of these neutron emissions is presented, with results obtained from both simulations and measurements using several diagnostics (activation samples, bubble detectors and Time-of-Flight detectors), leading to a neutron yield of ~$4.10^7$ neutrons/shot. Similar neutron emissions were observed during shots with and without DPM, while fewer X-rays are produced when the DPM is used, making this tool interesting to adjust the neutrons/X-rays ratio for some applications like combined neutron/X-ray radiography.

   ↳ physics.acc-phhep-exnucl-exEur.Phys.J.Plus(2024)·3 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.