Mon·Feb 26, 2018Monday·February 26, 2018

1. 01*

   Constraining the optical potential in the search for eta-mesic 4He

   M. Skurzok🇵🇱 · P. Moslal · N. G. Kelkar🇨🇴 · S. Hirenzaki🇯🇵 · H. Nagahiro🇯🇵 · N. Ikeno🇯🇵

   A consistent description of the $dd\to$ ${}^4\text{mbox}He\eta$ and $dd\to$ (${}^4$He$\eta$)${}_{bound}\to X$ cross sections was recently proposed with a broad range of real ($V_0$) and imaginary (W0), $\eta$-${}^4$He optical potential parameters leading to a good agreement with the d d -> 4He eta data. Here we compare the predictions of the model below the $\eta$ production threshold, with the WASA-at-COSY excitation functions for the dd -> 3He N pi reactions to put stronger constraints on (V0, W0). The allowed parameter space (with |V_0| < \sim 60 MeV and |W_0| < \sim 7 MeV estimated at 90% CL ) excludes most optical model predictions of eta-4He nuclei except for some loosely bound narrow states.

   nucl-exPLB(2018)·22 citations
2. 02*

   Search for time modulations in the decay constant of 40K and 226Ra at the underground Gran Sasso Laboratory

   E. Bellotti🇮🇹 · C. Broggini🇮🇹 · G. Di Carlo🇮🇹 · M. Laubenstein🇮🇹 · R. Menegazzo🇮🇹

   Time modulations at per mil level have been reported to take place in the decay constant of several nuclei with period of one year (most cases) but also of about one month or one day. On the other hand, experiments with similar or better sensitivity have been unable to detect any modulation. In this letter we give the results of the activity study of two different sources: 40K and 226Ra. The two gamma spectrometry experiments have been performed underground at the Gran Sasso Laboratory, this way suppressing the time dependent cosmic ray background. Briefly, our measurements reached the sensitivity of 3.4 and 3.5 parts over 10^6 for 40K and 226Ra, respectively (1 sigma) and they do not show any statistically significant evidence of time dependence in the decay constant. We also give the results of the activity measurement at the time of the two strong X-class solar flares which took place in September 2017. Our data do not show any unexpected time dependence in the decay rate of 40K in correspondence with the two flares. To the best of our knowledge, these are the most precise and accurate results on the stability of the decay constant as function of time.

   nucl-exastro-ph.SRPLB(2018)·15 citations
3. 03*

   A femtoscopic Correlation Analysis Tool using the Schrödinger equation (CATS)

   D.L. Mihaylov🇩🇪 · V. Mantovani Sarti🇩🇪 · O.W. Arnold🇩🇪 · L. Fabbietti🇩🇪 · B. Hohlweger🇩🇪 · A.M. Mathis🇩🇪

   We present a new analysis framework called "Correlation Analysis Tool using the Schrödinger equation" (CATS) which computes the two-particle femtoscopy correlation function $C(k)$, with $k$ being the relative momentum for the particle pair. Any local interaction potential and emission source function can be used as an input and the wave function is evaluated exactly. In this paper we present a study on the sensitivity of $C(k)$ to the interaction potential for different particle pairs: p-p, p-$\mathrm{\Lambda }$, ${\mathrm{K}}^{-}$-p, ${\mathrm{K}}^{+}$-p, p-${\mathrm{\Xi }}^{-}$ and $\mathrm{\Lambda }$-$\mathrm{\Lambda }$. For the p-p Argonne $v_{18}$ and Reid Soft-Core potentials have been tested. For the other pair systems we present results based on strong potentials obtained from effective Lagrangians such as $\chi$EFT for p-$\mathrm{\Lambda }$, Jülich models for $\mathrm{K}(\bar{\mathrm{K}})$-N and Nijmegen models for $\mathrm{\Lambda }$-$\mathrm{\Lambda }$. For the p-${\mathrm{\Xi }}^{-}$ pairs we employ the latest lattice results from the HAL QCD collaboration. Our detailed study of different interacting particle pairs as a function of the source size and different potentials shows that femtoscopic measurements can be exploited in order to constrain the final state interactions among hadrons. In particular, small collision systems of the order of 1~fm, as produced in pp collisions at the LHC, seem to provide a suitable environment for quantitative studies of this kind.

   ↳ hep-phhep-exnucl-exnucl-thEPJC(2018)·125 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.