Wed·Sep 27, 2017Wednesday·September 27, 2017

1. 01*

   On ${}^{146}$Nd, ${}^{144}$Sm and other unexplored 2$\beta$ decay isotopes

   Francesco Nozzoli🇮🇹

   ${}^{146}$Nd is one of only four (over a total of 35 existing) 2${\beta }^{-}$ decay isotope candidates whose half-lives currently lack experimental limits. The $\alpha$ activity of the ${}^{146}$Sm daughter nuclide allows placement of limits on the 2$\beta$ decay using the ${}^{146}$Nd/${}^{142}$Nd abundance ratio ($T_{1/2}^{\beta \beta }\text{gsim}3\times 10^9$ yr) or direct search for ${}^{146}$Sm with accelerator mass spectrometers ($T_{1/2}^{\beta \beta }\text{gsim}4.5\times 10^{19}$ yr). With a similar approach, a modest ($\sim$ Gyr) first limit on half-lives for the other unexplored $2\beta$ unstable isotopes and competitive limits (few $10^{13}$yr) for ${}^{98}$Mo and ${}^{122}$Sn are also given. Finally, it is shown how the limit $T_{1/2}^{0\nu ϵ{\beta }^{+}}\text{gsim}10^{15}$ yr for the unexplored ${}^{144}$Sm $0\nu ϵ{\beta }^{+}$ decay may be obtained from the data of a GSO crystal scintillator.

   nucl-exhep-phnucl-thPRC(2018)·7 citations
2. 02*

   Quarkonium-photoproduction prospects at a fixed-target experiment at the LHC (AFTER@LHC)

   L. Massacrier🇫🇷 · J.P. Lansberg🇫🇷 · L. Szymanowski🇵🇱 · J. Wagner🇵🇱

   We report on the potentialities offered by a fixed-target experiment at the LHC using the proton and ion LHC beams (AFTER@LHC project) regarding the study of J/psi exclusive-photoproduction in pA and AA collisions. The foreseen usage of polarised targets (hydrogen, deuteron, helium) gives access to measurements of the Single-Transverse-Spin Asymmetries of this exclusive process, therefore allowing one to access the helicity-flip Generalised Parton Distribution (GPD) Eg. We detail the expected yields of photoproduced J/psi in proton-hydrogen and lead-hydrogen collisions and discuss the statistical uncertainties on the asymmetry measurement for one year of data taking at the LHC.

   nucl-exhep-exnucl-thCERN Proc.(2018)·7 citations
3. 03*

   The interplay of short-range correlations and nuclear symmetry energy in hard photon productions from heavy-ion reactions at Fermi energies

   Gao-Chan Yong🇨🇳 · Bao-An Li🇺🇸

   Within an isospin- and momentum-dependent transport model for nuclear reactions at intermediate energies, we investigate the interplay of the nucleon-nucleon short-range correlations (SRC) and nuclear symmetry energy $E_{sym}(\rho )$ on hard photon spectra in collisions of several Ca isotopes on ${}^{112}$Sn and ${}^{124}$Sn targets at a beam energy of 45 MeV/nucleon. It is found that over the whole spectra of hard photons studied, effects of the SRC overwhelm those due to the $E_{sym}(\rho )$. The energetic photons come mostly from the high-momentum tails (HMT) of single-nucleon momentum distributions in the target and projectile. Within the neutron-proton dominance model of SRC based on the consideration that the tensor force acts mostly in the isosinglet and spin-triplet nucleon-nucleon interaction channel, there are equal numbers of neutrons and protons, thus a zero isospin-asymmetry in the HMTs. Therefore, experimental measurements of the energetic photons from heavy-ion collisions at Fermi energies have the great potential to help us better understand the nature of SRC without any appreciable influence by the uncertain $E_{sym}(\rho )$. These measurements will be complementary to but also have some advantages over the ongoing and planned experiments using hadronic messengers from reactions induced by high-energy electrons or protons. Since the underlying physics of SRC and $E_{sym}(\rho )$ are closely correlated, a better understanding of the SRC will in turn help constrain the nuclear symmetry energy more precisely in a broad density range.

   ↳ nucl-thnucl-exPRC(2017)·43 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.