[1112.4154] Constraints on perturbative quadratic gravity via neutron stars

Authors: Cemsinan Deliduman, K. Y. Ekşi, Vildan Keleş

Date: 18 Dec 2011

Abstract: We study the structure of neutron stars in R+\beta Rˆ{\mu \nu} R_{\mu \nu} gravity model with perturbative method. We obtain mass-radius relations for six representative equations of state (EOSs). We find that deviations from the results of general relativity, comparable to the variations due to using different EoSs, are induced for |\beta| ~ 10ˆ11 cmˆ2. Some of the soft EoSs that are excluded within the framework of general relativity can be reconciled for certain values of \beta\ of this order with the 2 solar mass neutron star recently observed. For some of the EoSs we find that a new solution branch, which allows highly massive neutron stars, exists for values of \beta\ greater than a few 10ˆ11 cmˆ2. We find constraints on \beta\ for a variety of EoSs using the recent observational constraints on the mass-radius relation. The associated length scale \sqrt{\beta} ~ 10ˆ6 cm is of the order of the the typical radius of neutron stars, the probe used in this test. This implies that the true value of \beta\ is most likely much smaller than 10ˆ11 cmˆ2.

abs pdf

Dec 20, 2011

1112.4154 (/preprints)
2011-12-20, 09:05 [edit]

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Tantum in modicis, quantum in maximis