Mon·May 15, 2023Monday·May 15, 2023

1. 01*

   Recent Results and Future Prospects from the STAR Beam Energy Scan Program

   Zachary Sweger (for the STAR Collaboration)🇺🇸

   The STAR experiment at Brookhaven National Laboratory has completed data taking for the second phase of the beam energy scan (BES-II) program, including in a fixed-target (FXT) mode. The BES-II program has collected high-statistics data on Au+Au collisions in the high baryon-density region of the QCD phase diagram. Together those data cover a wide range of per-nucleon center-of-mass energy from 3~GeV to 27~GeV. Recent results and anticipated analyses will be discussed along with implications for mapping the QCD phase diagram and its critical point.

   nucl-exhep-ex5 citations
2. 02*

   Search for the critical point of strongly-interacting matter in ${}^{40}$Ar + ${}^{45}$Sc collisions at 150A GeV/c using scaled factorial moments of protons

   NA61/SHINE Collaboration: H. Adhikary🇵🇱 · P. Adrich🇵🇱 · K. K. Allison🇺🇸 · N. Amin🇩🇪 · E. V. Andronov🇷🇺 · T. Antićić🇭🇷 · I.-C. Arsene🇳🇴 · M. Bajda🇵🇱 · Y. Balkova🇵🇱 · M. Baszczyk🇵🇱 · D. Battaglia🇺🇸 · A. Bazgir🇵🇱 and 147 other authors

   The critical point of dense, strongly interacting matter is searched for at the CERN SPS in ${}^{40}$Ar + ${}^{45}$Sc collisions at 150A GeV/c. The dependence of second-order scaled factorial moments of proton multiplicity distribution on the number of subdivisions of transverse momentum space is measured. The intermittency analysis is performed using both transverse momentum and cumulative transverse momentum. For the first time, statistically independent data sets are used for each subdivision number. The obtained results do not indicate any statistically significant intermittency pattern. An upper limit on the fraction of critical proton pairs and the power of the correlation function is obtained based on a comparison with the Power-law Model developed for this purpose.

   nucl-exhep-exEPJC(2023)·25 citations
3. 03*

   Phase Transition Phenomenology with Nonparametric Representations of the Neutron Star Equation of State

   Reed Essick🇨🇦 · Isaac Legred🇺🇸 · Katerina Chatziioannou🇺🇸 · Sophia Han🇨🇳 · Philippe Landry🇨🇦

   Astrophysical observations of neutron stars probe the structure of dense nuclear matter and have the potential to reveal phase transitions at high densities. Most recent analyses are based on parametrized models of the equation of state with a finite number of parameters and occasionally include extra parameters intended to capture phase transition phenomenology. However, such models restrict the types of behavior allowed and may not match the true equation of state. We introduce a complementary approach that extracts phase transitions directly from the equation of state without relying on, and thus being restricted by, an underlying parametrization. We then constrain the presence of phase transitions in neutron stars with astrophysical data. Current pulsar mass, tidal deformability, and mass-radius measurements disfavor only the strongest of possible phase transitions (latent energy per particle $\gtrsim 100\mathrm{MeV}$). Weaker phase transitions are consistent with observations. We further investigate the prospects for measuring phase transitions with future gravitational-wave observations and find that catalogs of \result{$O(100)$} events will (at best) yield Bayes factors of $\sim 10:1$ in favor of phase transitions even when the true equation of state contains very strong phase transitions. Our results reinforce the idea that neutron star observations will primarily constrain trends in macroscopic properties rather than detailed microscopic behavior. Fine-tuned equation of state models will likely remain unconstrained in the near future.

   ↳ astro-ph.HEgr-qcnucl-exnucl-thPRD(2023)·61 citations
4. 04*

   Performance of prototype Dual Gain Multilayer Thick GEM with high-intensity heavy-ion beam injections in low-pressure hydrogen gas

   Chihiro Iwamoto · Shinsuke Ota🇯🇵 · Reiko Kojima · Hiroshi Tokieda · Seiya Hayakawa🇯🇵 · Yutaka Mizoi🇯🇵 · Taku Gunji🇯🇵 · Hidetoshi Yamaguchi🇯🇵 · Nobuaki Imai🇯🇵 · Masanori Dozono🇯🇵 · Ryo Nakajima · Olga Beliuskina🇫🇮 and 10 other authors

   A prototype Dual Gain Multilayer Thick Gas Electron Multilyer (DG-M-THGEM) with an active area of 10 cm $\times$ 10 cm was manufactured aiming at the production of a large-volume active-target time projection chamber which can work under the condition of high-intensity heavy-ion beam injections. The DG-M-THGEM has a alternating structure of electrodes and insulators. Effective gas gains of two regions, which are called beam and recoil regions, are separately controlled. Performance of the prototype DG-M-THGEM in hydrogen gas at a pressure of 40 kPa was evaluated. Irradiating a ${}^{132}$Xe beam, an effective gas gain lower than 100 with a charge resolution of 3% was achieved in the beam region while the effective gas gain of 2000 was maintained in the recoil region. Position distributions of measured charges along the beam axis were investigated in order to evaluate gain uniformity in the high intensity beam injection. The gain shift was estimated by simulations considering space charges in the drift region. The gain shift was suppressed within 3% even at the beam intensity of 2.5 $\times$ 10${}^6$ particles per second.

   ↳ physics.ins-detnucl-exPTEP(2023)·0 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.