Atomic Ionization by Scalar Dark Matter and Solar Scalars

Area of Science:

• Nuclear Physics
• Particle Physics
• Astrophysics

Background:

• Direct dark matter searches rely on precise calculations of particle interactions with atomic targets.
• Previous calculations of atomic ionization cross sections by scalar particles contained a significant flaw, overestimating results.

Purpose of the Study:

• To accurately calculate atomic ionization cross sections for scalar particles across a wide energy range.
• To establish direct bounds on scalar-electron couplings using experimental data.
• To investigate the potential explanation of solar particle excesses via scalar emission.

Main Methods:

• Calculating atomic ionization cross sections for scalar particles interacting with various elements (O, Na, Ar, Ca, Ge, I, Xe, W, Tl).
• Correcting for the violation of orthogonality between bound and continuum electron wave functions in previous models.
• Interpreting data from the Xenon1T experiment to derive new constraints.

Main Results:

• Identified and corrected a critical overestimation in previous ionization cross-section calculations.
• Established the first direct bounds on the coupling of scalar particles to electrons.
• Demonstrated that solar-emitted scalars could explain the observed excess in the Xenon1T experiment.
• Provided updated axio-ionization cross sections and numerical data.

Conclusions:

• The corrected cross sections provide a more accurate basis for dark matter searches.
• Direct limits on scalar dark matter in the ~1-10 keV mass range are established.
• Scalar particles emitted from the Sun offer a viable explanation for recent experimental anomalies.