Collective scattering of massive stars in higher order gravity

Abstract

In the weak field approximation of higher order gravity theory a gravitational potential is described by a Newtonian plus a Yukawa-like term. This new term is used to explain some aspects of galactic dynamics, without considering dark matter. Its presence modifies the scattering probability of a massive intruder star and relaxation time of the stellar system. ͓S0556-2821͑97͒05802-5͔ PACS number͑s͒: 04.50.ϩh, 95.35.ϩd

Thermodynamics and phase transitions of galactic clustering in higher-order modified gravity

“…The idea of modified gravity has been re-emerging with various justifications, see for example Refs. [25][26][27][28][29]. The MOND is also studied for the Milky Way and has found that inner Milky Way is completely dominated by baryon matter, which is in agreement with the predictions of standard cold dark matter (CDM) cosmology [30].…”

d*dibaryon in the extended quark-delocalization, color-screening model

“…The traditional meson-exchange model [1][2][3][4] describes the NN scattering data quantitatively very well, where the effective degrees of freedom are nucleons and mesons. The intermediate-and long-range parts of the NN interaction are attributed to two-pionexchange, usually parameterized in terms of a σ meson, and one-pion-exchange (OPE).…”

Can quark effects be observed in intermediate heavy ion collisions?

“…A possible extension to our current calculation is to consider Ref. [29] where a meson-baryon interaction is derived in the context of the Fock-Tani formalism and obtain a σ πN cross-section from quark physics. The influence of the internal quark structure to the ∆ ressonance can also be addressed and is straightforward.…”

“…One of the most successful models in this regime is the UrQMD [31]. From our present approach, general baryon-baryon cross-sections can be calculated, from [19] mesonmeson cross-sections are obtained and from [29] all meson-baryon cross-sections, that appear in UrQMD, can be derived incorporating quark interchange.…”