Search results for "nuclear reaction"
showing 10 items of 449 documents
D mesic nuclei
2010
The energies and widths of several D-0 meson bound states for different nuclei are obtained using a D-meson selfenergy in the nuclear medium, which is evaluated in a selfconsistent manner using techniques of unitarized coupled-channel theory. The kernel of the meson-baryon interaction is based on a model that treats heavy pseudoscalar and heavy vector mesons on equal footing, as required by heavy quark symmetry. We find D-0 bound states in all studied nuclei, from C-12 up to Pb-208. The inclusion of vector mesons is the keystone for obtaining an attractive D-nucleus interaction that leads to the existence of D-0-nucleus bound states, as compared to previous studies based on SU(4) flavor sym…
Color glass condensate at next-to-leading order meets HERA data
2020
We perform the first dipole picture fit to HERA inclusive cross section data using the full next-to-leading order (NLO) impact factor combined with an improved Balitsky-Kovchegov evolution including the dominant effects beyond leading logarithmic accuracy at low $x$. We find that three different formulations of the evolution equation that have been proposed in the recent literature result in a very similar description of HERA data, and robust predictions for future deep inelastic scattering experiments. We find evidence pointing towards a significant nonperturbative contribution to the structure function for light quarks, which stresses the need to extend the NLO impact factor calculation t…
Azimuthal correlations of electrons from heavy-flavor decay with hadrons inp+pand Au+Au collisions atsNN=200GeV
2011
Measurements of electrons from the decay of open-heavy-flavor mesons have shown that the yields are suppressed in Au+Au collisions compared to expectations from binary-scaled p+p collisions. These measurements indicate that charm and bottom quarks interact with the hot dense matter produced in heavy-ion collisions much more than expected. Here we extend these studies to two-particle correlations where one particle is an electron from the decay of a heavy-flavor meson and the other is a charged hadron from either the decay of the heavy meson or from jet fragmentation. These measurements provide more detailed information about the interactions between heavy quarks and the matter, such as whet…
Relativistic corrections to the vector meson light front wave function
2020
We compute a light front wave function for heavy vector mesons based on long distance matrix elements constrained by decay width analyses in the Non Relativistic QCD framework. Our approach provides a systematic expansion of the wave function in quark velocity. The first relativistic correction included in our calculation is found to be significant, and crucial for a good description of the HERA exclusive $\mathrm{J}/\psi$ production data. When looking at cross section ratios between nuclear and proton targets, the wave function dependence does not cancel out exactly. In particular the fully non-relativistic limit is found not to be a reliable approximation even in this ratio. The important…
Progress on nuclear reaction rates affecting the stellar production of 26Al
2023
Abstract The radioisotope 26Al is a key observable for nucleosynthesis in the Galaxy and the environment of the early Solar System. To properly interpret the large variety of astronomical and meteoritic data, it is crucial to understand both the nuclear reactions involved in the production of 26Al in the relevant stellar sites and the physics of such sites. These range from the winds of low- and intermediate-mass asymptotic giant branch stars; to massive and very massive stars, both their Wolf–Rayet winds and their final core-collapse supernovae (CCSN); and the ejecta from novae, the explosions that occur on the surface of a white dwarf accreting material from a stellar companion. Several r…
The endpoint of the rp-process
1997
Abstract The endpoint of rp-process nucleosynthesis in X-ray bursts determines the fuel consumption, the energy generation, and the abundance pattern of the produced nuclei. To investigate the time structure of rp-process nucleosynthesis, we used a nuclear reaction network including nuclei from H to Sn. We found that if 2p-capture reactions are included, the synthesis of nuclei heavier than Kr proceeds faster than previously thought. Therefore, in most X-ray bursts large amounts of nuclei in the A=80–100 region are expected to be produced. With an escape factor of about 1%, X-ray bursts could account for the large observed solar system abundances of the light p-nuclei like 92 Mo and 96 Ru t…
Differential cross section for the reaction 2H(γ, p)n from 133 to 158 MeV
1991
The cross section for the reaction 2H(γ, p)n has been measured at laboratory photon energies Eγ = 133−158 MeV and c.m. angles between 30° and 150°. The reaction was induced by a tagged bremsstrahlung photon beam incident on a liquid deuterium target. The uncertainty in the absolute cross sections is ⩽ 5%. There is now reasonable agreement between recent measurements in this energy region and the overall data set now defines the cross section sufficiently well to provide a test of current models of the reaction.
NURE: An ERC project to study nuclear reactions for neutrinoless double beta decay
2017
Neutrinoless double beta decay (0{\nu}\b{eta}\b{eta}) is considered the best potential resource to determine the absolute neutrino mass scale. Moreover, if observed, it will signal that the total lepton number is not conserved and neutrinos are their own anti-particles. Presently, this physics case is one of the most important research beyond Standard Model and might guide the way towards a Grand Unified Theory of fundamental interactions. Since the \b{eta}\b{eta} decay process involves nuclei, its analysis necessarily implies nuclear structure issues. The 0{\nu}\b{eta}\b{eta} decay rate can be expressed as a product of independent factors: the phase-space factors, the nuclear matrix elemen…
Electron structure, ultra-dense hydrogen and low energy nuclear reactions
2019
In this paper, a simple Zitterbewegung electron model, proposed in a previous work, is presented from a different perspective based on the principle of mass- frequency equivalence. A geometric- electromagnetic interpretation of mass, relativistic mass, De Broglie wavelength, Proca, Klein- Gordon, Dirac and Aharonov- Bohm equations in agreement with the model is proposed. A non-relativistic, Zitterbewegung interpretation of the 3.7 keV deep hydrogen level found by J. Naudts is presented. According to this perspective, ultra-dense hydrogen can be conceived as a coherent chain of bosonic electrons with protons or deuterons located in the center of their Zitterbewegung orbits. This approach sug…
Discovery of the proton emitting nucleus $^{159}$Re
2007
Fund. para Cienc. Tecnol., FCT, Minist. Cienc. Tecnol.;Fundacao Calouste Gulbenkian;Fundacao Luso-Americana