We show that neutron star binaries can be ideal laboratories to probe hidden sectors with a long range force. In particular, it is possible for gravitational wave detectors such as LIGO and Virgo to resolve the correction of waveforms from ultralight
dark gauge bosons coupled to neutron stars. We observe that the interaction of the hidden sector affects both the gravitational wave frequency and amplitude in a way that cannot be fitted by pure gravity.
Motivated by the recent excess in the diphoton invariant mass near 750 GeV, we explore a supersymmetric extension of the Standard Model that includes the minimal set of superpartners as well as additional Dirac partner chiral superfields in the adjoi
nt representation for each gauge group. The bino partner pseudoscalar is identified as the 750 GeV resonance, while superpotential interactions between it and the gluino (wino) partners yield production via gluon fusion (decay to photon pairs) at one-loop. The gauginos and these additional adjoint superpartners are married by a Dirac mass and must also have Majorana masses. While a large wino partner Majorana mass is necessary to explain the excess, the gluino can be approximately Dirac-like, providing benefits consistent with being both supersoft (loop corrections to the scalar masses from Dirac gauginos are free of logarithmic enhancements) and supersafe (the experimental limits on the squark/gluino masses can be relaxed due to the reduced production rate). Consistency with the measured Standard Model-like Higgs boson mass is imposed, and a numerical exploration of the parameter space is provided. Models that can account for the diphoton excess are additionally characterized by having couplings that can remain perturbative up to very high scales, while remaining consistent with experimental constraints, the Higgs boson mass, and an electroweak scale which is not excessively fine tuned.
We describe a realistic, renormalizable, supersymmetric ``quindecuplet model in which the top quark, left handed bottom quark, and up-type Higgs boson are composite, with a compositeness scale $sim 1-3$ TeV. The top-Higgs Yukawa coupling is a dynamic
ally generated strong interaction effect, and is naturally much larger than any other Yukawa coupling. The light quark doublets and right-handed up-type quarks are also composite but at higher energies; the hierarchy of quark masses and mixings is due to a hierarchy in the compositeness scales. Flavor changing neutral currents are naturally suppressed, as is baryon number violation by Planck-scale dimension five operators. The model predicts that the most easily observable effects would be on $b$-quark physics and on the $rho$ parameter. In particular a small negative $Deltarho=-epsilon$ leads to $Delta R_b> +2epsilon$. There are effects on $B$ meson mixing and on flavor-changing neutral-current $b$-quark decays to leptons which might be detectable, but not on $brightarrow sgamma$. The model also suggests the supersymmetry-breaking mass for the right handed top squark might be considerably larger than that of the left handed top squark.
