Probing the relaxed relaxion and Higgs portal scenarios with XENON1T scintillation and ionization data

Ranny Budnik, Hyungjin Kim, Oleksii Matsedonskyi, Gilad Perez, Yotam Soreq

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)

Abstract

We study the recent XENON1T excess in the context of solar scalar, specifically in the framework of Higgs portal and the relaxion model. We show that mϕ=1.9  keV and gϕe=2.4×10−14 can explain the observed excess in science run 1 (SR1) analysis in the 1–7 keV range. In the minimal scenarios we consider, the best-fit parameters are in tension with stellar cooling bounds. Despite this fact, the excess represents an example bringing attention to two interesting effects of general relevance. First, the scalar-Higgs mixing angle reproducing the excess, sinθ≃10−8, is intriguingly close to the maximum value of mixing angle for the technical naturalness of the scalar mass. While finding a parameter value very close to its theoretical limit may naively seem an unlikely coincidence, we demonstrate that there exists a class of models which generically saturate the mixing naturalness bound. Secondly, we discuss a possibility that a large density of red giant stars may trigger a phase transition, resulting in a local scalar mass increase suppressing the stellar cooling. For the particular case of minimal relaxion scenarios, we find that such type of chameleon effects is automatically present but they can not ease the cooling bounds. They are however capable of triggering a catastrophic phase transition in the entire Universe. Following this observation we derive a new set of bounds on the relaxed relaxion parameter space. Finally, we present two nonminimal models that demonstrate how the cooling bounds can be relaxed as a result of high density effects.
Original languageEnglish
Article number015012
Pages (from-to)1-
Number of pages11
JournalPhysical review. D
Volume104
Issue number1
DOIs
Publication statusPublished - Jul 2021

Funding

We would like to thank Kfir Blum, Diego Redigolo, and Tomer Volansky for fruitful discussions, and Abhishek Banerjee for technical support. We are grateful to Oz Davidi for his contributions to this project in its initial phase. The work of R. B. is supported by ISF Grant No. 1937/12. R. B. is the incumbent of the Arye and Ido Dissentshik Career Development Chair. The work of O. M. is supported by the Foreign Postdoctoral Fellowship Program of the Israel Academy of Sciences and Humanities. The work of G. P. is supported by grants from The U.S.- Israel Binational Science Foundation (BSF), Israel Science Foundation (ISF), German Israeli Foundation (GIF), Yeda-Sela-SABRA-WRC, and the Segre and the Friedrich Wilhelm Bessel Research Awards. Y. S. is supported by the BSF (NSF-BSF program Grant No. 2018683) and by the Azrieli Foundation. Y. S. is a Taub fellow (supported by the Taub Family Foundation).

Fingerprint

Dive into the research topics of 'Probing the relaxed relaxion and Higgs portal scenarios with XENON1T scintillation and ionization data'. Together they form a unique fingerprint.

Cite this