Wed·Aug 5, 2020Wednesday·August 5, 2020

1. 01*

   Candidates for the 5$\alpha$ condensed state in ${}^{20}$Ne

   S. Adachi · Y. Fujikawa🇯🇵 · T. Kawabata · H. Akimune🇯🇵 · T. Doi🇯🇵 · T. Furuno · T. Harada🇯🇵 · K. Inaba🇯🇵 · S. Ishida · M. Itoh🇯🇵 · C. Iwamoto · N. Kobayashi🇯🇵 and 8 other authors

   We conducted the coincidence measurement of $\alpha$ particles inelastically scattered from ${}^{20}$Ne at $0^{\circ }$ and decay charged particles in order to search for the alpha-particle condensed state. We compared the measured excitation-energy spectrum and decay branching ratio with the statistical-decay-model calculations, and found that the newly observed states at $E_x$ = 23.6, 21.8, and 21.2 MeV in ${}^{20}$Ne are strongly coupled to a candidate for the 4$\alpha$ condensed state in ${}^{16}$O. This result presents the first strong evidence that these states are the candidates for the 5$\alpha$ condensed state.

   nucl-exPLB(2021)·43 citations
2. 02*

   Accelerator Based Production of ${}^{225}$Ac for Cancer Treatment

   H. Kumawat · S. V. Suryanarayana

   Targeted Alpha Therapy potentially offers a more specific action in killing tumor cells and less damage to neighbouring normal cells compared to $\beta$-emitters. ${}^{225}$Ac along with three other $\alpha$-emitting daughter nuclei ${}^{221}$Fr, ${}^{217}$At and ${}^{213}$Po have significant potency for clinical use. Monte carlo simulation has been carried out using MONC code for production routes of ${}^{225}$Ac for its possible generation using proton accelerators with Thorium-232 and Radium-226 targets. All the calculations has been carried out using global model parameters without adjusting for individual target. The study reveals that proton beam of 20-30MeV energy with 5$\mu$A current on radium-226 target can give rise to 1Ci of ${}^{225}$Ac activity in a week of irradiation. Thorium irradiation at low proton energy produces smaller ${}^{225}$Ac activity but one can benefit from high current, stable proton accelerators. Proton energy of 100MeV or above with hundreds of $\mu$A current can produce reasonable ${}^{225}$Ac activity for practical use. However, the contamination of other co-produced radio-isotopes is much less at low proton energy hence low energy high current proton accelerators are also viable alternative to generate Actinium-225 radio isotope.

   ↳ physics.med-phnucl-exnucl-thphysics.app-ph0 citations
3. 03*

   Limits on the flux of nuclearites and other heavy compact objects from the "Pi of the Sky" project

   Lech Wiktor Piotrowski🇯🇵 · Katarzyna Małek🇵🇱 · Lech Mankiewicz🇵🇱 · Marcin Sokołowski🇦🇺 · Grzegorz Wrochna🇵🇱 · Adam Zadrożny🇵🇱 · Aleksander Filip Żarnecki🇵🇱

   Many theories predict the existence of very heavy compact objects, that in terms of sizes would belong to the realms of nuclear or atomic physics, but in terms of masses could extend to the macroscopic world, reaching kilograms, tonnes or more. If they exist, it is likely that they reach our planet with high speeds and cross the atmosphere. Due to their high mass to size ratio and huge energy, in many cases, they would leave behind a trail in the form of sound and seismic waves, etches, or light in transparent media. Here we show results of a search for such objects in visual photographs of the sky taken by the "Pi of the Sky" experiment, illustrated with the most stringent limits on the isotropic flux of incoming so-called nuclearites, spanning between $5.4\cdot 10^{-20}$ and $2.2\cdot 10^{-21}{\mathrm{cm}}^{-2}{\mathrm{s}}^{-1}{\mathrm{sr}}^{-1}$ for masses between 100 g and 100 kg. In addition we establish a directional flux limit under an assumption of static "sea" of nuclearites in the Galaxy, which spans between $1.5\cdot 10^{-18}$ and $2.1\cdot 10^{-19}{\mathrm{cm}}^{-2}{\mathrm{s}}^{-1}$ in the same mass range. The general nature of the limits presented should allow one to constrain many specific models predicting the existence of heavy compact objects and both particle physics and astrophysical processes leading to their creation, and their sources.

   ↳ astro-ph.HEhep-exnucl-exPRL(2020)·21 citations
4. 04*

   Amplitude- and truncated partial-wave analyses combined: A novel, almost theory-independent single-channel method for extracting photoproduction multipoles directly from measured data

   A. Švarc🇭🇷 · Y. Wunderlich🇩🇪 · L. Tiator🇩🇪

   Amplitude- and truncated partial-wave analyses are combined into a single procedure and a novel, almost theory-independent single-channel method for extracting multipoles directly from measured data is developed. In practice, we have created a two-step procedure which is fitted to the same data base: in the first step we perform an energy independent amplitude analysis where continuity is achieved by constraining the amplitude phase, and the result of this first step is then taken as a constraint for the second step where a constrained, energy independent, truncated partial-wave analysis is done. The method is tested on the world collection of data for $\eta$ photoproduction, and the obtained fit-results are very good. The sensitivity to different possible choices of amplitude phase is investigated and it is demonstrated that the present data base is insensitive to notable phase changes, due to an incomplete database. New measurements are recommended to remedy the problem.

   ↳ nucl-thnucl-exPRC(2020)·8 citations
5. 05*

   Hanbury Brown--Twiss Interferometry and Collectivity in Small Systems

   Christopher Plumberg🇸🇪

   Hanbury Brown--Twiss interferometry (HBT) provides crucial insights into both the space-time structure and the momentum-space evolution of ultrarelativistic nuclear collisions at freeze-out. In particular, the dependence of the HBT radii on the transverse pair momentum $K_T$ and the system charged multiplicity $d{N}_{\mathrm{ch}}/d\eta$ may reflect the mechanisms driving collective behavior in small systems. This paper argues that certain features observed in the multiplicity dependence of the HBT radii can be naturally understood if small systems evolve hydrodynamically at high-multiplicity. This study thus establishes a baseline for the multiplicity dependence of HBT in hydrodynamics which may prove useful in discriminating between competing models of collectivity in nuclear collisions.

   ↳ nucl-thnucl-exPRC(2020)·11 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.