Mon·Feb 27, 2023Monday·February 27, 2023

1. 01*

   Measuring the cross section of the ${}^{15}$N($\alpha$,$\gamma$)${}^{19}$F reaction using a single-fluid bubble chamber

   D. Neto🇺🇸 · K. Bailey🇺🇸 · J. F. Benesch🇺🇸 · B. Cade · B. DiGiovine · A. Freyberger🇺🇸 · J. M. Grames🇺🇸 · A. Hofler🇺🇸 · R. J. Holt🇺🇸 · R. Kazimi🇺🇸 · D. Meekins🇺🇸 · M. McCaughan🇺🇸 and 8 other authors

   ${}^{15}$N($\alpha$,$\gamma$)${}^{19}$F is believed to be the primary means of stellar nucleosynthesis of fluorine. Here we present the use of a single-fluid bubble chamber to measure the cross section of the time-inverse photo-dissociation reaction. The method benefits from a luminosity increase of several orders of magnitude due to the use of a thicker liquid target -- when compared to thin films or gas targets -- and from the reciprocity theorem. We discuss the results of an experiment at the Thomas Jefferson National Accelerator Facility, where the cross section of the photodisintegration process ${}^{19}$F($\gamma$, $\alpha$)${}^{15}$N was measured by bombarding a superheated fluid of C${}_3$F${}_8$ with bremsstrahlung $\gamma$-rays produced by impinging a 4 - 5.5 MeV electron beam on a Cu radiator. From the photodissociation yield the cross section was extracted by performing a convolution with a Monte Carlo-generated $\gamma$-ray beam spectrum. The measurement produced a cross section that was then time inverted using the reciprocity theorem. The cross section for the ${}^{15}$N($\alpha$,$\gamma$)${}^{19}$F reaction was determined down to a value in the range of hundreds of picobarns. With further improvements of the experimental setup the technique could potentially push cross section measurements down to the single picobarn range.

   nucl-exPRC(2023)·3 citations
2. 02*

   In-medium properties of the light and heavy-light mesons in a light-front quark model

   Ahmad Jafar Arifi🇰🇷 · Parada. T. P. Hutauruk🇰🇷 · Kazuo Tsushima🇧🇷

   We investigate the in-medium properties of pseudoscalar and vector mesons with the light-light and heavy-light quarks in a light-front quark model, using the in-medium quark properties computed by the quark-meson coupling model. Both models are constructed on an equal footing with the constituent quark degree of freedom. Here, we particularly focus on the weak decay constants and distribution amplitudes (DAs) of the mesons in symmetric nuclear matter. We find that the weak decay constants decrease as nuclear density increases for $\pi$, $K$, $D$, and $B$ pseudoscalar as well as $\rho$, $K^{\ast }$, $D^{\ast }$, and $B^{\ast }$ vector mesons, where their properties in free space have good agreement with the available experimental and lattice QCD data. A larger reduction is found for the light-light quark pseudoscalar mesons, while a smaller reduction is found for the heavy-light quark vector mesons, in particular, with the bottom quark. We discuss the effect of the vector potential on the weak decay constants and present our predictions for the in-medium modifications of DAs. Also, a comparison with the free space lattice QCD data is made.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2023)·22 citations
3. 03*

   Demonstration of a 25-picosecond single-photon time resolution with gaseous photomultiplication

   K. Matsuoka🇯🇵 · R. Okubo · Y. Adachi🇯🇵

   Photosensitive gaseous detectors with a simple photoelectron multiplication mechanism of resistive plate chambers (RPCs) are expected to have both a large photocoverage and an excellent time resolution and to be low-cost. To demonstrate the time resolution of the RPC-based photodetectors, we built a prototype detector with a LaB${}_6$ photocathode. It was tested with a picosecond pulse laser and the intrinsic time resolution for single photons was measured to be $25.0\pm 1.1$ ps at a gain of $3.3\times 10^6$.

   ↳ physics.ins-dethep-exnucl-exNucl.Instrum.Meth.A(2023)·5 citations
4. 04*

   Study and perspective on neutron beam divergence improvement achievable by the combination of two or more neutron collimating systems

   Oriol Sans-Planell🇮🇹 · Francesco Cantini · Marco Costa🇮🇹 · Francesco Grazzi🇮🇹 · Manuel Morgano · Masako Yamada

   This communication presents the results obtained at an experimental campaign at PSI BOA beamline using the combination of the ANET Compact Neutron Collimator (CNC) with the actual BOA pin-hole system. Through extensive resolution campaigns, it has been possible to quantify and understand the effects of improvement on the beam divergence when combining the two collimating systems. A new theoretical approach to this problem is described and discussed. The effect is expected not to be limited to the specific case that has been studied at PSI BOA but to have a more general validity for neutron collimation systems.

   ↳ physics.ins-detnucl-exphysics.app-phJ.Phys.Conf.Ser.(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.