Closing the spontaneous-scalarization window with binary pulsars

Kavli Affiliate: Lijing Shao

| First 5 Authors: Junjie Zhao, Paulo C. C. Freire, Michael Kramer, Lijing Shao, Norbert Wex

| Summary:

Benefitting from the unequaled precision of the pulsar timing technique,
binary pulsars are important testbeds of gravity theories, providing some of
the tightest bounds on alternative theories of gravity. One class of
well-motivated alternative gravity theories, the scalar-tensor gravity, predict
large deviations from general relativity for neutron stars through a
nonperturbative phenomenon known as spontaneous scalarization. This effect,
which cannot be tested in the Solar System, can now be tightly constrained
using the latest results from the timing of a set of 7 binary pulsars,
especially with the updated parameters of PSRs J2222$-$0137, J0737$-$3039A and
J1913+1102. Using new timing results, we constrain the neutron star’s effective
scalar coupling, which describes how strongly neutron stars couple to the
scalar field, to a level of $|alpha_A| lesssim 6 times 10^{-3}$ in a
Bayesian analysis. Our analysis is thorough, in the sense that our results
apply to all neutron star masses and all reasonable equations of state of dense
matters, in the full relevant parameter space. It excludes the possibility of
spontaneous scalarization of neutron stars, at least within a class of
scalar-tensor gravity theories.

| Search Query: ArXiv Query: search_query=au:”Lijing Shao”&id_list=&start=0&max_results=10

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