Thu·Oct 28, 2021Thursday·October 28, 2021

1. 01*

   First $\beta$-decay spectroscopy of ${}^{135}$In and new $\beta$-decay branches of ${}^{134}$In

   IDS Collaboration

   The $\beta$ decay of the neutron-rich ${}^{134}$In and ${}^{135}$In was investigated experimentally in order to provide new insights into the nuclear structure of the tin isotopes with magic proton number $Z=50$ above the $N=82$ shell. The $\beta$-delayed $\gamma$-ray spectroscopy measurement was performed at the ISOLDE facility at CERN, where indium isotopes were selectively laser-ionized and on-line mass separated. Three $\beta$-decay branches of ${}^{134}$In were established, two of which were observed for the first time. Population of neutron-unbound states decaying via $\gamma$ rays was identified in the two daughter nuclei of ${}^{134}$In, ${}^{134}$Sn and ${}^{133}$Sn, at excitation energies exceeding the neutron separation energy by 1 MeV. The $\beta$-delayed one- and two-neutron emission branching ratios of ${}^{134}$In were determined and compared with theoretical calculations. The $\beta$-delayed one-neutron decay was observed to be dominant $\beta$-decay branch of ${}^{134}$In even though the Gamow-Teller resonance is located substantially above the two-neutron separation energy of ${}^{134}$Sn. Transitions following the $\beta$ decay of ${}^{135}$In are reported for the first time, including $\gamma$ rays tentatively attributed to ${}^{135}$Sn. In total, six new levels were identified in ${}^{134}$Sn on the basis of the $\beta \gamma \gamma$ coincidences observed in the ${}^{134}$In and ${}^{135}$In $\beta$ decays. A transition that might be a candidate for deexciting the missing neutron single-particle $13/2^{+}$ state in ${}^{133}$Sn was observed in both $\beta$ decays and its assignment is discussed. Experimental level schemes of ${}^{134}$Sn and ${}^{135}$Sn are compared with shell-model predictions. Using the fast timing technique, half-lives of the $2^{+}$, $4^{+}$ and $6^{+}$ levels in ${}^{134}$Sn were determined.

   nucl-exPRC(2021)·12 citations
2. 02*

   Studying the QGP with Jets at the LHC and RHIC

   Leticia Cunqueiro🇫🇷 · Anne M. Sickles🇺🇸

   We review the current status of jet measurements in heavy-ion collisions at the Large Hadron Collider (LHC) and the Relativistic Heavy Ion Collider (RHIC). We discuss how the current measurements provide information about the quark-gluon plasma and discuss near future opportunities at both RHIC and the LHC.

   nucl-exhep-phPPNP(2022)·194 citations
3. 03*

   Improved Nuclear Physics Near $A=61$ Refines Urca Neutrino Luminosities in Accreted Neutron Star Crusts

   Zach Meisel🇺🇸 · Alec Hamaker🇺🇸 · G. Bollen🇺🇸 · B.A. Brown🇺🇸 · M. Eibach🇩🇪 · K. Gulyuz🇺🇸 · C. Izzo🇺🇸 · C. Langer🇩🇪 · F. Montes🇺🇸 · W.-J Ong🇺🇸 · D. Puentes🇺🇸 · M. Redshaw🇺🇸 and 7 other authors

   We performed a Penning trap mass measurement of ${}^{61}\mathrm{Zn}$ at the National Superconducting Cyclotron Laboratory and NuShellX calculations of the ${}^{61}\mathrm{Zn}$ and ${}^{62}\mathrm{Ga}$ structure using the GXPF1A Hamiltonian to obtain improved estimates of the ${}^{61}\mathrm{Zn}(p,\gamma {)}^{62}\mathrm{Ga}$ and ${}^{60}\mathrm{Cu}(p,\gamma {)}^{61}\mathrm{Zn}$ reaction rates. Surveying astrophysical conditions for type-I X-ray bursts with the code MESA, implementing our improved reaction rates, and taking into account updated nuclear masses for ${}^{61}\mathrm{V}$ and ${}^{61}\mathrm{Cr}$ from the recent literature, we refine the neutrino luminosity from the important mass number $A=61$ urca cooling source in accreted neutron star crusts. This improves our understanding of the thermal barrier between deep heating in the crust and the shallow depths where extra heat is needed to explain X-ray superbursts, as well as the expected signature of crust urca neutrino emission in light curves of cooling transients.

   nucl-exnucl-thPRC(2022)·6 citations
4. 04*

   Electromagnetic form factors of baryons in nuclear medium

   G. Ramalho🇧🇷 · K. Tsushima🇧🇷 · J.P.B.C. de Melo🇧🇷

   The electromagnetic structure of the baryons is modified in the nuclear medium. The modifications can be inferred from the comparison between the electromagnetic form factors in medium with the respective form factor in vacuum. Of particular interest is the ratio between the electric and magnetic form factors in medium ($G_E^{\ast }/G_M^{\ast }$) and vacuum ($G_E/G_M$) of the octet baryon. The deviation of the double ratios ($G_E^{\ast }/G_M^{\ast })/(G_E/G_M)$ from unity measures the impact of the medium modification of the electromagnetic structure in a nuclear medium. Measurements of the double ratios $(G_E^{\ast }/G_M^{\ast })/(G_E/G_M)$ for different nuclear densities may become available in a near future using the polarization-transfer method developed at Jefferson Lab. We present estimates of the double ratios of octet baryons based on a covariant constituent quark model, which takes into account pion cloud excitations of the baryon cores,for different nuclear densities. Our results manifest different features, namely, enhancement or quenching depending on the baryon flavor content.

   ↳ hep-phhep-exhep-latnucl-ex+1PoS(2022)·1 citation
5. 05*

   A New Semi-Empirical Model for Cosmic Ray Muon Flux Estimation

   Junghyun Bae🇺🇸 · Stylianos Chatzidakis🇺🇸

   Cosmic ray muons have emerged as a non-conventional high-energy radiation probe to monitor dense and large objects. Muons are the most abundant cosmic radiation on Earth, however, their flux at sea level is approximately 10,000 min^-1m^-2 much less than that of induced radiation. In addition, cosmic ray muon flux depends on not only various natural conditions (e.g., zenith angle, altitude, or solar activities) but also the geometric characteristic of detectors. Since the low muon flux typically results in long measurement times, an accurate estimation of measurable muon counts is important for muon applications. Here we propose a simple and versatile semi-empirical model to improve the accuracy in muon flux estimation at all zenith angles by incorporating the geometric parameters of detectors, and we name this the Effective Solid Angle model. To demonstrate the functionality, our model is compared with i) the cosine-squared, ii) PARMA model, and iii) Monte-Carlo simulations, and iv) measurements. Our results show that the muon count rate estimation capability is significantly improved resulting in increasing a mean C/E from 0.7 to 0.95. By selecting an appropriate intensity correlation, the model can be easily extended to estimate muon flux at various altitude and underground level.

   ↳ astro-ph.IMastro-ph.HEhep-exnucl-ex+1PTEP(2022)·2 citations
6. 06*

   A Cosmic Ray Muon Spectrometer Using Pressurized Gaseous Cherenkov Radiators

   Junghyun Bae🇺🇸 · Stylianos Chatzidakis🇺🇸

   In this work, we propose a new approach to cosmic ray muon momentum measurement using multiple pressurized gaseous Cherenkov radiators. Knowledge of cosmic ray muon momentum has the potential to significantly improve and expand the use of a variety of recently developed muon-based radiographic techniques. However, existing muon tomography systems rely only on muon tracking and have no momentum measurement capabilities which reduces the image resolution and requires longer measurement times. A fieldable cosmic ray muon spectrometer with momentum measurement capabilities for use in muon scattering tomography is currently missing. We address this challenge by optimally varying the pressure of multiple gaseous Cherenkov radiators and identifying the radiators that are triggered by muons that have momentum higher than the Cherenkov threshold momentum. We evaluate the proposed concept through Geant4 simulations and demonstrate that the cosmic ray muon momentum spectrum can be reconstructed with sufficient accuracy and resolution for two scenarios: (i) a perfect Cherenkov muon spectrometer and (ii) a practical spectrometer where noise is introduced in the form of scintillation and transition radiation photons. To quantify the accuracy of spectrometer, the concept of true and false classifications are introduced. The fraction of true classification is investigated for each momentum level in a practical radiator. The average classification rate for momentum range of 0.2 to 7.0 GeV/c with uncertainty of 1 GeV/c is approximately 85%.

   ↳ physics.ins-detastro-ph.IMhep-exnucl-ex2021 IEEE NSS MIC Conference·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.