Tue·May 24, 2022Tuesday·May 24, 2022

1. 01*

   Proton Compton Scattering from Linearly Polarized Gamma Rays

   X. Li🇨🇳 · M. W. Ahmed🇺🇸 · A. Banu🇺🇸 · C. Bartram🇺🇸 · B. Crowe🇺🇸 · E. J. Downie🇺🇸 · M. Emamian🇺🇸 · G. Feldman · H. Gao · D. Godagama🇺🇸 · H. W. Grießhammer🇺🇸 · C. R. Howell🇺🇸 and 18 other authors

   Differential cross sections for Compton scattering from the proton have been measured at scattering angles of $55^{\circ }$, $90^{\circ }$, and $125^{\circ }$ in the laboratory frame using quasimonoenergetic linearly (circularly) polarized photon beams with a weighted mean energy value of 83.4\,MeV (81.3\,MeV). These measurements were performed at the High Intensity Gamma-Ray Source facility at the Triangle Universities Nuclear Laboratory. The results are compared to previous measurements and are interpreted in the chiral effective field theory framework to extract the electromagnetic dipole polarizabilities of the proton, which gives ${\alpha }_{E1}^p=13.8\pm 1.2_{\mathrm{stat}}\pm 0.1_{\mathrm{BSR}}\pm 0.3_{\mathrm{theo}},{\beta }_{M1}^p=0.2\mp 1.2_{\mathrm{stat}}\pm 0.1_{\mathrm{BSR}}\mp 0.3_{\mathrm{theo}}$ in units of 10${}^{-4}$\, fm${}^3$.

   nucl-exPRL(2022)·13 citations
2. 02*

   Direct determination of the excitation energy of quasi-stable isomer ${}^{180m}$Ta

   D.A. Nesterenko🇫🇮 · K. Blaum🇩🇪 · P. Delahaye🇫🇷 · S. Eliseev🇩🇪 · T. Eronen🇫🇮 · P. Filianin🇩🇪 · Z. Ge🇩🇪 · M. Hukkanen🇫🇮 · A. Kankainen🇫🇮 · Yu.N. Novikov🇷🇺 · A.V. Popov🇷🇺 · A. Raggio🇫🇮 · M. Stryjczyk🇫🇮 · V. Virtanen🇫🇮

   ${}^{180m}$Ta is a naturally abundant quasi-stable nuclide and the longest-lived nuclear isomer known to date. It is of interest for, among others, the search for dark matter, for the development of a gamma laser and for astrophysics. So far, its excitation energy has not been measured directly but has been based on an evaluation of available nuclear reaction data. We have determined the excitation energy of this isomer with high accuracy using the Penning-trap mass spectrometer JYFLTRAP. The determined mass difference between the ground and isomeric states of ${}^{180}$Ta yields an excitation energy of 76.79(55) keV for ${}^{180m}$Ta. This is the first direct measurement of the excitation energy and provides a better accuracy than the previous evaluation value, 75.3(14) keV.

   nucl-exPRC(2022)·5 citations
3. 03*

   Search for Neutrinoless Double-Beta Decay of ${}^{76}$Ge with a Natural Broad Energy Germanium Detector

   CDEX collaboration: W. H. Dai · H. Ma · Q. Yue · Z. She · K. J. Kang · Y. J. Li · M. Agartioglu · H. P. An · J. P. Chang · Y. H. Chen · J. P. Cheng · Z. Deng and 73 other authors

   A natural broad energy germanium (BEGe) detector is operated in the China Jinping Underground Laboratory (CJPL) for a feasibility study of building the next generation experiment of the neutrinoless double-beta (0{$\nu \beta \beta$}) decay of ${}^{76}$Ge. The setup of the prototype facility, characteristics of the BEGe detector, background reduction methods, and data analysis are described in this paper. A background index of 6.4$\times$10${}^{-3}$ counts/(keV$\cdot$kg$\cdot$day) is achieved and 1.86 times lower than our previous result of the CDEX-1 detector. No signal is observed with an exposure of 186.4 kg$\cdot$day, thus a limit on the half life of ${}^{76}$Ge 0$\nu \beta \beta$ decay is set at T${}_{1/2}^{0\nu }$ $>$ 5.62$\times$10${}^{22}$ yr at 90% C.L.. The limit corresponds to an effective Majorana neutrino mass in the range of 4.6 $\sim$ 10.3 eV, dependent on the nuclear matrix elements.

   nucl-exhep-exphysics.ins-detPRD(2022)·22 citations
4. 04*

   Azimuthal anisotropy measurement of (multi-)strange hadrons in Au+Au collisions at $\sqrt{s_{\text{NN}}}$ = 54.4 GeV

   STAR Collaboration: M. S. Abdallah · B. E. Aboona · J. Adam · L. Adamczyk · J. R. Adams · J. K. Adkins · I. Aggarwal · M. M. Aggarwal · Z. Ahammed · D. M. Anderson · E. C. Aschenauer · J. Atchison and 359 other authors

   Azimuthal anisotropy of produced particles is one of the most important observables used to access the collective properties of the expanding medium created in relativistic heavy-ion collisions. In this paper, we present second ($v_2$) and third ($v_3$) order azimuthal anisotropies of $K_S^0$, $\varphi$, $\Lambda$, $\Xi$ and $\Omega$ at mid-rapidity ($|y|<$1) in Au+Au collisions at $\sqrt{s_{\text{NN}}}$ = 54.4 GeV measured by the STAR detector. The $v_2$ and $v_3$ are measured as a function of transverse momentum and centrality. Their energy dependence is also studied. $v_3$ is found to be more sensitive to the change in the center-of-mass energy than $v_2$. Scaling by constituent quark number is found to hold for $v_2$ within 10%. This observation could be evidence for the development of partonic collectivity in 54.4 GeV Au+Au collisions. Differences in $v_2$ and $v_3$ between baryons and anti-baryons are presented, and ratios of $v_3$/$v_2^{3/2}$ are studied and motivated by hydrodynamical calculations. The ratio of $v_2$ of $\varphi$ mesons to that of anti-protons ($v_2(\varphi )/v_2(\bar{p})$) shows centrality dependence at low transverse momentum, presumably resulting from the larger effects from hadronic interactions on anti-proton $v_2$.

   nucl-exhep-exPRC(2023)·16 citations
5. 05*

   Difference of measured proton and He3 EDMs: a reduced systematics test of T-reversal invariance

   Richard M. Talman🇺🇸

   The upper limit on (time reversal symmetry T-violating) permanent hadron electric dipole moments (EDMs) is the PSI neutron EDM value; $d_n=(0.0\pm 1.1_{\mathrm{stat}}\pm 0.2_{\mathrm{sys}}\times 10^{-26})e$\,cm. This paper describes an experiment to be performed at a BNL-proposed CLIP project which is to be capable of producing intense polarized beams of protons, $p$, helions (He${}^3$ nuclei), h, and other isotopes. The EDM prototype ring PTR (proposed at COSY Lab, Juelich) is expected to measure individual particle EDMs (for example $EDM\_p$ for the proton) using simultaneous counter-rotating polarized proton beams, with statistical error $\pm 10^{-30}$e.cm after one year running time, four orders of magnitude less than the PSI neutron EDM upper limit, and with comparable systematic error. A composite particle, the helion faces T-symmetry constraints more challenging than the proton. Any measurably large value of $$\Delta ={\mathrm{EDM}}_h-{\mathrm{EDM}}_p,$$ the difference of helion and proton EDMs, would represent BSM physics. The plan is to replicate PTR at BNL. The dominant systematic error would be canceled two ways, both made possible by phase-locking "doubly-magic" 38.6\,MeV proton and 39.2\,MeV helion spin tunes. This stabilizes their MDM-induced in-plane precessions, without affecting their EDM-induced out-of-plane precessions. The dominant systematic error would therefore cancel in the meaurement of $\Delta$ in a fixed field configuration. Another systematic error cancellation will come from averaging runs for which both magnetic field and beam circulation directions are reversed. Precise magnetic field reversal is made possible by the reproducible absolute frequency phase-locking over long runs to eliminate the need for (impractically precise) magnetic field measurement. Risk of EDM measurement failure is discussed in a final appendix.

   ↳ physics.acc-phnucl-exJINST(2022)·6 citations
6. 06*

   Attractive $N$-$\varphi$ Interaction and Two-Pion Tail from Lattice QCD near Physical Point

   Yan Lyu🇨🇳 · Takumi Doi🇯🇵 · Tetsuo Hatsuda🇯🇵 · Yoichi Ikeda🇯🇵 · Jie Meng🇨🇳 · Kenji Sasaki🇯🇵 · Takuya Sugiura🇯🇵

   First results on the interaction between the $\varphi$-meson and the nucleon ($N$) are presented based on the ($2+1$)-flavor lattice QCD simulations with nearly physical quark masses. Using the HAL QCD method, the spacetime correlation of the $N$-$\varphi$ system in the spin 3/2 channel is converted into the $N$-$\varphi$ scattering phase shift through the interaction potential. The $N$-$\varphi$ potential appears to be a combination of a short-range attractive core and a long-range attractive tail. The latter is found to be consistent with the two-pion exchange (TPE) obtained from the interaction between a color-dipole and the nucleon. The resultant scattering length and effective range for $m_{\pi }=$ 146.4 MeV are $a_0^{(3/2)}=-1.43(23{)}_{stat.}{\left({}_{-06}^{+36}\right)}_{syst.}\mathrm{fm}$ and $r_{\mathrm{eff}}^{(3/2)}=2.36(10{)}_{stat.}{\left({}_{-48}^{+02}\right)}_{syst.}\mathrm{fm}$, respectively. The magnitude of the scattering length is shown to have nontrivial dependence of $m_{\pi }$ and is sensitive to the existence of the long-range tail from TPE.

   ↳ hep-lathep-exhep-phnucl-ex+1PRD(2022)·73 citations
7. 07*

   Systematic shell model study for $N=82$ and $N=126$ isotones and nuclear isomers

   Bharti Bhoy🇮🇳 · Praveen C. Srivastava🇮🇳

   In the present work, we have done a systematic shell model study of $N=82$ and $N=126$ isotones. For the $N=82$ isotones, we have performed calculations using SN100PN interaction, while for $N=126$ isotones, we have used KHPE interaction. Similarities between these two isotonic chains have been reported, using the strong resemblance between the high-$j$ orbitals. Apart from the nuclear spectroscopic properties, we have also explained different isomeric states in these two regions. In the $N$ =82 region, we have mainly discussed the properties of the $6^{+}$ and $17/2^{+}$ isomers, while in the $N=126$ region for $8^{+}$, $11^{-}$, $21/2^{-}$ and $29/2^{+}$ isomers. We have reported $B(E2)$, $B(E3)$, $g$-factor, and quadrupole moments of the isomeric states for comparison in these two isotonic chains.

   ↳ nucl-thnucl-exJ.Phys.G(2022)·14 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.