Tue·Aug 23, 2016Tuesday·August 23, 2016

1. 01*

   Momentum dependence of the imaginary part of the $\omega$- and ${\eta }^{\prime }$-nucleus optical potential

   S. Friedrich · M. Nanova · V. Metag · F. N. Afzal · D. Bayadilov · B. Bantes · R. Beck · M. Becker · S. Böse · K.-T. Brinkmann · V. Crede · P. Drexler and 49 other authors

   The photoproduction of $\omega$ and ${\eta }^{\prime }$ mesons off carbon and niobium nuclei has been measured as a function of the meson momentum for incident photon energies of 1.2-2.9 GeV at the electron accelerator ELSA. The mesons have been identified via the $\omega \to {\pi }^0\gamma \to 3\gamma$ and ${\eta }^{\prime }\to {\pi }^0{\pi }^0\eta \to 6\gamma$ decays, respectively, registered with the CBELSA/TAPS detector system. From the measured meson momentum distributions the momentum dependence of the transparency ratio has been determined for both mesons. Within a Glauber analysis the in-medium $\omega$ and ${\eta }^{\prime }$ widths and the corresponding absorption cross sections have been deduced as a function of the meson momentum. The results are compared to recent theoretical predictions for the in-medium $\omega$ width and ${\eta }^{\prime }$-N absorption cross sections. The energy dependence of the imaginary part of the $\omega$- and ${\eta }^{\prime }$-nucleus optical potential has been extracted. The finer binning of the present data compared to the existing data allows a more reliable extrapolation towards the production threshold. The modulus of the imaginary part of the ${\eta }^{\prime }$ nucleus potential is found to be about three times smaller than recently determined values of the real part of the ${\eta }^{\prime }$-nucleus potential, which makes the ${\eta }^{\prime }$ meson a suitable candidate for the search for meson-nucleus bound states. For the $\omega$ meson, the modulus of the imaginary part near threshold is comparable to the modulus of the real part of the potential. As a consequence, only broad structures can be expected which makes the observation of $\omega$ mesic states very difficult experimentally.

   nucl-exEPJA(2026)·35 citations
2. 02*

   Chiral EFT based nuclear forces: Achievements and challenges

   R. Machleidt🇺🇸 · F. Sammarruca🇺🇸

   During the past two decades, chiral effective field theory has become a popular tool to derive nuclear forces from first principles. Two-nucleon interactions have been worked out up to sixth order of chiral perturbation theory and three-nucleon forces up to fifth order. Applications of some of these forces have been conducted in nuclear few- and many-body systems---with a certain degree of success. But in spite of these achievements, we are still faced with great challenges. Among them is the issue of a proper uncertainty quantification of predictions obtained when applying these forces in {\it ab initio} calculations of nuclear structure and reactions. A related problem is the order by order convergence of the chiral expansion. We start this review with a pedagogical introduction and then present the current status of the field of chiral nuclear forces. This is followed by a discussion of representative examples for the application of chiral two- and three-body forces in the nuclear many-body system including convergence issues.

   ↳ nucl-thnucl-exPhys.Scripta(2016)·112 citations
3. 03*

   The fluctuations of quadrangular flow

   Giuliano Giacalone🇫🇷 · Li Yan🇫🇷 · Jacquelyn Noronha-Hostler🇺🇸 · Jean-Yves Ollitrault🇫🇷

   The ATLAS Collaboration has measured for the first time the fourth cumulant of quadrangular flow, $v_4\{4{\}}^4$. Unlike the fourth cumulants of elliptic and triangular flows, it presents a change of sign above 30\% centrality. We show that this change of sign is predicted by event-by-event hydrodynamics. We argue that it results from the combined effects of a nonlinear hydrodynamic response, which couples quadrangular flow to elliptic flow, and elliptic flow fluctuations.

   ↳ nucl-thhep-phnucl-exJ.Phys.Conf.Ser.(2017)·15 citations
4. 04*

   Long-Baseline Neutrino Experiments

   M. V. Diwan🇺🇸 · V. Galymov🇫🇷 · X. Qian🇺🇸 · A. Rubbia🇨🇭

   We review long-baseline neutrino experiments in which neutrinos are detected after traversing macroscopic distances. Over such distances neutrinos have been found to oscillate among flavor states. Experiments with solar, atmospheric, reactor, and accelerator neutrinos have resulted in a coherent picture of neutrino masses and mixing of the three known flavor states. We will summarize the current best knowledge of neutrino parameters and phenomenology with our focus on the evolution of the experimental technique. We proceed from the first evidence produced by astrophysical neutrino sources to the current open questions and the goals of future research.

   ↳ hep-exnucl-exAnn.Rev.Nucl.Part.Sci.(2016)·50 citations
5. 05*

   Light yield of an undoped CsI crystal coupled directly to a photomultiplier tube at 77 Kelvin

   Jing Liu🇺🇸 · Masaki Yamashita🇯🇵 · Arun Kumar Soma🇺🇸

   A light yield of 20.4 $\pm$ 0.8 photoelectrons/keV was achieved with an undoped CsI crystal coupled directly to a photomultiplier tube at 77 Kelvin. This is by far the largest yield in the world achieved with CsI crystals. An energy threshold that is several times lower than the current dark matter experiments utilizing CsI(Tl) crystals may be achievable using this technique. Together with novel CsI crystal purification methods, the technique may be used to improve the sensitivities of dark matter and coherent elastic neutrino-nucleus scattering experiments. Also measured were the scintillation light decay constants of the undoped CsI crystal at both room temperature and 77 Kelvin. The results are consistent with those in the literature.

   ↳ physics.ins-dethep-exnucl-exJINST(2016)·9 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.