Wed·Sep 8, 2021Wednesday·September 8, 2021

1. 01*

   Determination of $1p$ and $2p$ stripping excitation functions for ${}^{16}$O+${}^{142}$Ce using a Recoil Mass Spectrometer

   Rohan Biswas · S. Nath · J. Gehlot · Gonika · Chandra Kumar🇮🇳 · A. Parihari · N. Madhavan · A. Vinayak · Amritraj Mahato · Shoaib Noor🇵🇰 · Phurba Sherpa · Kazuyuki Sekizawa🇯🇵

   We report the first direct measurement of differential transfer cross sections using a Recoil Mass Spectrometer. Absolute differential $1p$ and $2p$-stripping cross sections at ${\theta }_{c.m.}=180^{\circ }$ have been determined for the system ${}^{16}$O+${}^{142}$Ce by detecting the heavier target-like ions at the focal plane of the Heavy Ion Reaction Analyzer. Focal plane spectra have been compared with the results of a semi-microscopic Monte-Carlo simulation to unambiguously identify the transfer channels. Transmission efficiency of the target-like ions through the spectrometer has also been estimated using the simulation. The methodology adopted in this work can be applied to other recoil separators. The measured excitation functions for the reactions ${}^{142}{\mathrm{Ce}(}^{16}{\mathrm{O},}^{15}{\mathrm{N})}^{143}\mathrm{Pr}$ and ${}^{142}{\mathrm{Ce}(}^{16}{\mathrm{O},}^{14}{\mathrm{C})}^{144}\mathrm{Nd}$ have been compared with coupled reaction channel calculations. An excellent matching between measurement and theory has been obtained. For $1p$-stripping, major contribution to the cross section has been found to be the transfer of a proton from ${}^{16}\mathrm{O}$ to the $2d_{\frac{5}{2}}$ excited state of ${}^{143}\mathrm{Pr}$, leaving behind ${}^{15}\mathrm{N}$ in the $1p_{\frac{1}{2}}$ ground state. Transfer of a cluster of two protons from ${}^{16}\mathrm{O}$ to the $2^{+}$ excited state of ${}^{144}\mathrm{Nd}$, resulting in ${}^{14}\mathrm{C}$ in the $0^{+}$ ground state, appears to be the most probable cause for $2p$-stripping. Measured transfer probabilities for $1p$ and $2p$ channels have been compared with Time-Dependent Hartree-Fock calculations. Proton stripping channels are found to be more favourable compared to neutron pick-up channels. However, the theory overpredicts measurement hinting at the need for extended approaches with explicit treatment of pairing correlations in the calculations.

   nucl-exnucl-thEPJA(2023)·4 citations
2. 02*

   Binding energy shifts from heavy-ion experiments in a nuclear statistical equilibrium model

   S. Mallik🇮🇳 · H. Pais🇵🇹 · F. Gulminelli🇫🇷

   Chemical constants extracted from ${}^{124}$Xe+ ${}^{124}$Sn collisions at 32 AMeV are compared to the predictions of an extended Nuclear Statistical Equilibrium model including mean-field interactions and in-medium binding energy shifts for the light ($Z\le 2$) clusters. The ion species and density dependence of the in-medium modification is directly extracted from the experimental data. We show that the shift increases with the mass of the cluster and the density of the medium, and we provide a simple linear fit for future use in astrophysical simulations in the framework of the CompOSE data base. The resulting mass fractions are computed in representative thermodynamic conditions relevant for supernova and neutron star mergers. A comparison to the results of a similar analysis of the same data performed in the framework of a relativistic mean-field model shows a good agreement at low density, but significant discrepancies close to the Mott dissolution of clusters in the dense medium.

   ↳ nucl-thastro-ph.SRnucl-exEPJA(2021)·2 citations
3. 03*

   Holographic charm and bottom pentaquarks III: Excitations through photo-production of heavy mesons

   Yizhuang Liu🇵🇱 · Kiminad A. Mamo🇺🇸 · Maciej A. Nowak🇵🇱 · Ismail Zahed🇺🇸

   We consider the photo-excitation of charm and bottom pentaquarks with the holographic assignments $[\frac{1}{2}{\frac{1}{2}}^{-}{]}_{S=0,1}$ and $[\frac{1}{2}{\frac{3}{2}}^{-}{]}_{S=1}$, in the photo-production of heavy vector mesons such as charmonia and bottomonia near threshold. We use a Witten diagram to combine the s-channel photo-excitation of holographic pentaquarks with a massive t-channel graviton or tensor glueball exchange, to extract the scattering amplitude for heavy meson photo-production in the threshold region. The pentaquark signal is too weak to be detected at current electron facilities.

   ↳ hep-phhep-thnucl-exnucl-thPRD(2021)·10 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.