Tue·Aug 9, 2022Tuesday·August 9, 2022

1. 01*

   Searching for New Physics with DarkLight at the ARIEL Electron-Linac

   The DarkLight Collaboration · E. Cline · R. Corliss · J. C. Bernauer · R. Alarcon · R. Baartman · S. Benson · J. Bessuille · D. Ciarniello · A. Christopher · A. Colon · W. Deconinck and 34 other authors

   The search for a dark photon holds considerable interest in the physics community. Such a force carrier would begin to illuminate the dark sector. Many experiments have searched for such a particle, but so far it has proven elusive. In recent years the concept of a low mass dark photon has gained popularity in the physics community. Of particular recent interest is the ${}^8$Be and ${}^4$He anomaly, which could be explained by a new fifth force carrier with a mass of 17 MeV/$c^2$. The proposed DarkLight experiment would search for this potential low mass force carrier at ARIEL in the 10-20 MeV e${}^{+}$e${}^{-}$ invariant mass range. This proceeding will focus on the experimental design and physics case of the DarkLight experiment.

   nucl-exphysics.ins-detJ.Phys.Conf.Ser.(2022)·11 citations
2. 02*

   Evaluation of the response of plastic scintillator bars and measurement of neutron capture time in non-reactor environment for the ISMRAN experiment

   R.Dey🇮🇳 · P.K.Netrakanti🇮🇳 · D.K.Mishra🇮🇳 · S.P.Behera · R.Sehgal🇮🇳 · V.Jha🇮🇳 · L.M.Pant🇮🇳

   We present a detailed study on detector response to different radioactive sources and the measurements of non-reactor environmental backgrounds with the Indian Scintillator Matrix for Reactor Anti-Neutrinos (ISMRAN) detector setup consisting of 9$\times$10 Plastic Scintillator Bars (PSBs) array at BARC, Mumbai. These measurements are useful in the context of the ISMRAN detector setup, which will be used to detect the reactor anti-neutrinos (${\overline{\text{ensuremath}\nu }}_e$) and measure its energy spectra, through the inverse beta decay (IBD) process. A GEANT4 based Monte Carlo (MC) simulation is used to understand the optical transmission, energy resolution and energy non-linearity of the ISMRAN detector. A detailed analysis procedure has been developed to understand the natural radioactive, cosmogenic and cosmic muon-induced backgrounds with the ISMRAN detector setup in a non-reactor environment, based on their energy deposition, number of bars hit as well as topological event selection criteria in position and time for triggered events. Data and MC simulated distributions of reconstructed sum energy and number of bars hit has been compared for the radioactive $\gamma$ + positron source such as ${}^{22}\mathrm{Na}$ placed at the center of the ISMRAN array. Fast neutron energy response and capture time distribution in ISMRAN array has been studied using a novel technique involving Time of Flight (TOF) of the measured fast neutrons. The observed characteristic neutron capture time ( $\tau$ ) of 68.29 $\pm$ 9.48 $\mu$s is in good agreement with $\sim$65 $\mu$s obtained from MC simulation. These experimentally measured results will be useful for discriminating the correlated and uncorrelated background events from the true IBD events in reactor ON and OFF conditions inside the reactor hall.

   ↳ physics.ins-dethep-exnucl-exNucl.Instrum.Meth.A(2022)·8 citations
3. 03*

   Weinberg operator contribution to the CP-odd nuclear force in the quark model

   Nodoka Yamanaka🇯🇵 · Makoto Oka🇯🇵

   The contribution of the CP violating three-gluon interaction, proposed by Weinberg, to the short-range CP-odd nuclear force is evaluated in the nonrelativistic quark model. We first show that the naive leading contribution generated by the quark exchange process vanishes at sufficiently short distance within the resonating group method, by considering the one-loop level gluon exchange CP-odd interquark potential induced by the Weinberg operator with massive quarks and gluons. We then estimate the true leading contribution by evaluating the gluonic correction to the CP-odd interquark potential in the closure approximation. It is found that the resulting irreducible CP-odd nuclear force is comparable to that generated by the chiral rotation of the CP-even short-range nuclear force, where the CP-odd mass calculated with QCD sum rules is used as input. The explicit calculation of the electric dipole moment (EDM) of the ${}^3$He nucleus yields $d_{{}^3\mathrm{He}}^{(\mathrm{irr})}(w)=-1.5we$ MeV. The total ${}^3$He EDM, accounting for the intrinsic nucleon EDM, the pion-exchange and the short-range CP-odd nuclear force, is $d_{{}^3\mathrm{He}}^{(\mathrm{tot})}(w)=20_{-11}^{+14}we$ MeV, with the dominant effect coming from the intrinsic nucleon EDM.

   ↳ nucl-thhep-exhep-phnucl-exPRD(2022)·7 citations
4. 04*

   Fast neutrino cooling in the accreting neutron star MXB 1659-29

   Melissa Mendes🇩🇪 · Farrukh J. Fattoyev🇺🇸 · Andrew Cumming · Charles Gale🇨🇦

   Modelling of crust heating and cooling across multiple accretion outbursts of the low mass X-ray binary MXB 1659-29 indicates that the neutrino luminosity of the neutron star core is consistent with direct Urca reactions occurring in $\sim 1\%$ of the core volume. We investigate this scenario with neutron star models that include a detailed equation of state parametrized by the slope of the nuclear symmetry energy $L$, and a range of neutron and proton superfluid gaps. We find that the predicted neutron star mass depends sensitively on $L$ and the assumed gaps. We discuss which combinations of superfluid gaps reproduce the inferred neutrino luminosity. Larger values of $L\gtrsim 80\mathrm{MeV}$ require superfluidity to suppress dUrca reactions in low mass neutron stars, i.e. that the proton or neutron gap is sufficiently strong and extends to high enough density. However, the largest gaps give masses near the maximum mass, making it difficult to accommodate colder neutron stars. We consider models with reduced dUrca normalization as an approximation of alternative, less efficient, fast cooling processes in exotic cores. We find solutions with a larger emitting volume, providing a more natural explanation for the observed neutrino luminosity, provided the fast cooling process is within a factor of $\sim 1000$ of dUrca. The heat capacities of our models span the range from fully-paired to fully-unpaired nucleons meaning that long term observations of core cooling could distinguish between models. We discuss the impact of future constraints on neutron star mass, radius and the density dependence of the symmetry energy.

   ↳ astro-ph.HEnucl-exnucl-thApJ(2022)·13 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.