Revisiting supernova constraints on a light CP-even scalar

Abstract

A light CP-even Standard Model (SM) gauge-singlet scalar $S$ can be produced abundantly in the supernova core, via the nucleon bremsstrahlung process $NN\to NNS$, due to its mixing with the SM Higgs boson. Including the effective $S$ coupling to both nucleons and the pion mediators, we evaluate the production amplitude for the $S$ particle and point out a key difference with the well-known light CP-odd scalar (axion) and vector boson (dark photon) cases. Taking the subsequent decay and re-absorption of $S$ into account, we present a complete calculation of the energy loss rate for the $S$ particle. We then use the SN1987A luminosity constraints to derive updated supernova limits on the mixing of the scalar $S$ with the SM Higgs boson. We find that the mixing angle $\sin \theta$ with the SM Higgs is excluded only in the narrow range of $3.9\times 10^{-7}$ to $7.0\times 10^{-6}$, depending on the scalar mass up to about 147 MeV, beyond which the supernova limit disappears.

22 pages, 6 figures, one error fixed in Eq. (4.3), Figures 4, 5 and 6 updated

References in corpus (11)

• Secluded WIMP Dark Matter
• Gauge Singlet Scalars as Cold Dark Matter
• Singlet Higgs Phenomenology and the Electroweak Phase Transition
• Measurement of the Differential Branching Fraction and Forward-Backword Asymmetry for B->K(*)l+l-
• Light Dark Matter: Models and Constraints
• Study of the decay K+ => pi+,nu,nubar in the momentum region 140<Ppi<199 MeV/c
• Supernova Bounds on the Dark Photon Using its Electromagnetic Decay
• BBN for the LHC: constraints on lifetimes of the Higgs portal scalars
• New measurement of the K+- --> pi+-mu+mu- decay
• Self-consistent Dark Matter Simplified Models with an s-channel scalar mediator
• Impact of Nucleon-Nucleon Bremsstrahlung Rates Beyond One-Pion Exchange

Cited by in corpus (5)

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• Search for a light Higgs boson in single-photon decays of ${\rm Y}(1S)$ using ${\rm Y}(2S)\to {\pi }^{+}{\pi }^{-}{\rm Y}(1S)$ tagging method
• Light scalars in neutron star mergers