Wed·Jun 28, 2023Wednesday·June 28, 2023

1. 01*

   Recoil-Order and Radiative Corrections to the aCORN Experiment

   F.E. Wietfeldt🇺🇸 · W.A. Byron🇺🇸 · B. Collett🇺🇸 · M.S. Dewey🇺🇸 · T.R. Gentile🇺🇸 · F. Gluck🇩🇪 · M.T. Hassan🇺🇸 · G.L. Jones🇺🇸 · A. Komives🇺🇸 · J.S. Nico🇺🇸 · E.J. Stephenson🇺🇸

   The aCORN experiment measures the electron-antineutrino $a$-coefficient in free neutron decay. We update the previous aCORN results to include radiative and recoil corrections to first order, and discuss a key issue in the comparison of results from different $a$-coefficient experimental methods when these effects are considered. The corrected combined result is $\overline{a}=-0.10779\pm 0.00125(\mathrm{stat})\pm 0.00133(\mathrm{sys})$, averaged over the full Fermi neutron beta spectrum. The corresponding corrected result for the ratio of weak coupling constants $\lambda =G_A/G_V$ is $\lambda =-1.2712\pm 0.0061$. This improves agreement with previous $a$-coefficient experiments, in particular the 2020 aSPECT result

   nucl-exPRC(2024)·12 citations
2. 02*

   ${}^{12}$C+${}^{12}$C scattering as the reference system for reaction cross section

   Shingo Tagami🇯🇵 · Tomotsugu Wakasa🇯🇵 · Masanobu Yahiro🇯🇵

   In our previous paper, we tested the chiral (Kyushu) folding model for ${}^{12}$C+${}^{12}$C scattering, since the profile function in the Glauber mode is constructed for the system. We found that the folding model is reliable for reaction cross sections ${\sigma }_{\mathrm{R}}$ in $30\text{lsim}{E}_{\mathrm{lab}}\text{lsim}100$~MeV and $250\text{lsim}{E}_{\mathrm{lab}}\text{lsim}400$~MeV. Accurate data are available for ${}^{12}$C scattering on ${}^9$Be, ${}^{12}$C, ${}^{27}$Al targets in $30\text{lsim}{E}_{\mathrm{lab}}\text{lsim}400$~MeV. We determine matter radius $r_m(\exp )$ of ${}^{12}$C from the accurate ${\sigma }_{\mathrm{R}}(\exp )$, using the Kyushu $g$-matrix folding model. Our result is $r_{\mathrm{m}}^{12}(\exp )=2.352\pm 0.013$~fm for ${}^{12}$C. The model is applied for the accurate data on ${}^{12}$C+${}^{27}$Al scattering, and yields $r_{\mathrm{m}}(\exp )=2.936\pm 0.012$~fm for ${}^{27}$Al. Our conclusion is that $r_{\mathrm{m}}(\exp )=2.352\pm 0.013$~fm agrees with $r_{\mathrm{m}}(\exp )=2.35\pm 0.02$~fm determined from interaction cross sections by Tanihata {\it et. al.}.

   nucl-exnucl-th2 citations
3. 03*

   Charge-changing cross section measurements of 300 MeV/nucleon ${}^{28}$Si on carbon and data analysis

   Chang-Jian Wang · Ge Guo · Hooi Jin Ong · Yu-Nan Song · Bao-Hua Sun · Isao Tanihata · Satoru Terashima · Xiu-Lin Wei · Jun-Yao Xu · Xiao-Dong Xu · Ji-Chao Zhang · Yong Zheng and 16 other authors

   Charge-changing cross section (${\sigma }_{\text{cc}}$) measurements via the transmission method have made important progress recently aiming to determine the charge radii of exotic nuclei. In this work, we report a new ${\sigma }_{\text{cc}}$ measurement of 304(9) MeV/nucleon ${}^{28}$Si on carbon at the second Radioactive Ion Beam Line in Lanzhou (RIBLL2) and describe the data analysis procedure in detail. This procedure is essential to evaluate the systematic uncertainty in the transmission method. The determined ${\sigma }_{\mathrm{cc}}$ of 1125(11) mb is found to be consistent with the existing data at similar energies. The present work will serve as a reference in the ${\sigma }_{\text{cc}}$ determinations at RIBLL2.

   nucl-exCPC(2023)·10 citations
4. 04*

   Collider constraints on massive gravitons coupling to photons

   David d'Enterria (CERN)🇨🇭 · Malak Ait Tamlihat (Mohammed V University in Rabat)🇲🇦 · Laurent Schoeffel (CEA)🇫🇷 · Hua-Sheng Shao (LPTHE)🇫🇷 · Yahya Tayalati (Mohammed V University in Rabat)🇲🇦

   We study the discovery potential of massive graviton-like spin-2 particles coupled to standard model fields, produced in photon-photon collisions at the Large Hadron Collider (LHC) as well as in electron-positron ($e^{+}{e}^{-}$) collisions, within an effective theory with and without universal couplings. Our focus is on a massive graviton G coupled to the electromagnetic field, which decays via $\mathrm{G}\to \gamma \gamma$ and leads to a resonant excess of diphotons over the light-by-light scattering continuum at the LHC, and of triphoton final states at $e^{+}{e}^{-}$ colliders. Based on similar searches performed for pseudoscalar axion-like particles (ALPs), and taking into account the different cross sections, $\gamma \gamma$ partial widths, and decay kinematics of the pseudoscalar and tensor particles, we reinterpret existing experimental bounds on the ALP-$\gamma$ coupling into G-$\gamma$ ones. Using the available data, exclusion limits on the graviton-photon coupling are set down to $g_{\mathrm{G}\gamma \gamma }\approx 1$--0.05~TeV${}^{-1}$ for masses $m_{\mathrm{G}}\approx 100$~MeV--2~TeV. Such bounds can be improved by factors of 100 at Belle~II in the low-mass region, and of 4 at the HL-LHC at high masses, with their expected full integrated luminosities.

   ↳ hep-phhep-exnucl-exnucl-thPLB(2023)·24 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.