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Since the baryon-to-photon ratio "eta" is in some doubt at present, we ignore the constraints on eta from big bang nucleosynthesis (BBN) and fit the three key cosmological parameters (h, Omega_M, eta) to four other observational…

天体物理学 · 物理学 2022-03-23 G. Steigman , N. Hata , J. E. Felten

The available data on the $Q^2$ dependence of the $\gamma\gamma*(Q^2)\to K\bar K\pi$ reaction cross section in the energy region 1.35-1.55 GeV is explained by the $\eta(1475)$ resonance production in contrast to their conventional…

高能物理 - 唯象学 · 物理学 2011-09-13 N. N. Achasov , G. N. Shestakov

A recent Letter attempted to reconcile the disagreement between neutron resonance data and random matrix theory (RMT). To this end, a new formula was derived for transforming measured ({\Gamma}_{{\lambda}n}) to reduced…

核理论 · 物理学 2011-01-25 P. E. Koehler , F. Bečvář , M. Krtička , J. A. Harvey , K. H. Guber

Differential cross sections of the reaction gamma d to K+ Sigma- (p) have been measured with the CLAS detector at Jefferson Lab using incident photons with energies between 1.1 and 3.6 GeV. This is the first complete set of strangeness…

We review the present understanding of etaprime and eta meson physics and these mesons as a probe of gluon dynamics in low-energy QCD. Recent highlights include the production mechanism of eta and etaprime mesons in proton-nucleon…

高能物理 - 唯象学 · 物理学 2019-03-27 Steven D. Bass , Pawel Moskal

The $P$-wave charmonium decays $h_{c}\rightarrow\gamma\eta^{(\prime)}$ are revisited by taking into account relativistic corrections. The decay amplitudes are derived in the Bethe-Salpeter formalism, in which the involved one-loop integrals…

高能物理 - 唯象学 · 物理学 2021-06-09 Jun-Kang He , Chao-Jie Fan

A truncated partial-wave analysis is performed for $\eta$-photoproduction using the polarization observables $\sigma_0, \Sigma, T, E, F$ and $G$. Different truncation orders are analyzed for six energy bins within the range of…

核理论 · 物理学 2024-04-12 Philipp Kroenert , Yannick Wunderlich , Farah Afzal , Annika Thiel

The $\gamma$-process in core-collapse and/or type Ia supernova explosions is thought to explain the origin of the majority of the so-called $p$ nuclei (the 35 proton-rich isotopes between Se and Hg). Reaction rates for $\gamma$-process…

核实验 · 物理学 2015-03-09 G. G Kiss , T. Szücs , T. Rauscher , Zs Török , L. Csedreki , Zs Fülöp , Gy Gyürky , Z. Halász

We present in this talk recent investigations on the nucleon-like resonance N*(1675) newly found in eta photoproduction by the GRAAL, Tohoku LNS-gamma and CB-ELSA collaborations. We focus on the production mechanism of the N*(1675),…

高能物理 - 唯象学 · 物理学 2015-05-13 Ki-Seok Choi , Seung-il Nam , Atsushi Hosaka , Hyun-Chul Kim

To shed light on the deuteron radius puzzle we analyze the theoretical uncertainties of the nuclear structure corrections to the Lamb shift in muonic deuterium. We find that the discrepancy between the calculated two-photon exchange…

We explore how the $\eta$-$\pi^0$ mixing angle and the $\eta$ meson decay into $\pi^{+}\pi^{-}\pi^0$ and 3$\pi^{0}$ are modified in the nuclear medium on the basis of the in-medium chiral effective theory with the isospin asymmetry $\alpha$…

核理论 · 物理学 2015-01-30 Shuntaro Sakai , Teiji Kunihiro

A chiral quark-model approach is adopted to study the $\eta$ photoproduction off the quasi-free neutron and proton from a deuteron target. Good descriptions of the differential cross sections, total cross sections and beam asymmetries for…

核理论 · 物理学 2015-05-28 Xian-Hui Zhong , Qiang Zhao

The universal radiative corrections common to neutron and super-allowed nuclear beta decays (also known as ``inner'' corrections) are revisited in light of a recent dispersion relation study that found $+2.467(22)\%$, i.e.~about $2.4\sigma$…

高能物理 - 唯象学 · 物理学 2019-10-30 Andrzej Czarnecki , William J. Marciano , Alberto Sirlin

Possibilities of discriminating neutrons and gamma rays in the AGATA gamma-ray tracking spectrometer have been investigated with the aim of reducing the background due to inelastic scattering of neutrons in the high-purity germanium…

核实验 · 物理学 2009-09-09 A. Ataç , A. Kaşkaş , S. Akkoyun , M. Şenyiğit , T. Hüyük , S. O. Kara , J. Nyberg

Total absorption spectroscopy was used to investigate the beta-decay intensity to states above the neutron separation energy followed by gamma-ray emission in 87,88Br and 94Rb. Accurate results were obtained thanks to a careful control of…

A two mixing angle description of the pseudoscalar decay constants associated to the $\eta$-$\eta^\prime$ system is used to parametrize the theoretical amplitudes of the radiative decays $(\eta,\eta^\prime)\to\gamma\gamma$ and the coupling…

高能物理 - 唯象学 · 物理学 2009-04-25 R. Escribano

We present a reanalysis of the HeII Lyman alpha absorption towards the quasars HS1700+6416 and HE2347-4342 using new high S/N, optical observations. An alternative analysis method is applied, which fits the high quality, optical HI data…

天体物理学 · 物理学 2009-11-11 C. Fechner , D. Reimers

We investigate $\eta$ photoproduction off the neutron target, i.e., $\gamma n \to \eta n$, employing an effective Lagrangian method combining with a Regge approach. As a background, we consider nucleon exchange in the $s$-channel diagram…

高能物理 - 唯象学 · 物理学 2019-04-17 Jung-Min Suh , Sang-Ho Kim , Hyun-Chul Kim