The standard model is currently recognized as the most successful theory for
studying particles and their interactions. However, it still fails to
account for some important astronomy observations, such as the existence of
dark matter and dark energy. Physicists generally believe that there are new
particles beyond the standard model, which transmit new interactions between
standard model particles. Due to the weak effect of exotic interaction,
searching for exotic interactions is extremely challenging, and it is urgent
to explore new methods to improve experimental sensitivity.
In a study published in Science Advances, the research team led by Prof.
Peng Xinhua from University of Science and Technology of China of the
Chinese Academy of Sciences, collaborating with Prof. Dmitry Budker from
Helmholtz Institution, realized ultra-high precision search of exotic spin-
and velocity- dependent interactions beyond the standard model, and
amplified the magnetic field signal of exotic interactions at least two
orders of magnitude and applied the technique to the investigation of exotic
velocity-interactions based on their newly developed quantum spin-based
amplifier.
In this study, the researchers rotated a high-density Bi4Ge3O12 (BGO)
crystal at high speed to induce the interaction between the BGO crystal and
the xenon nucleus in the spin-based amplifier. This exotic interaction is
equivalent to generating an alternating oscillating magnetic field on the
nucleus, so the measurement of the exotic interaction can be converted into
a magnetic field detection. The quantum spin-based amplifier can amplify the
magnetic field to be measured at ultra-low noise levels, which greatly
improved the sensitivity of the exotic interaction search.
Given the possible interference of technical noise, researchers took
advantage of the velocity dependence of the exotic interaction to
effectively eliminate the interference signals such as vibration and
classical magnetic field.
They found no evidence of the existence of new particles in the search area,
and thus proposed a new class of bosons-nucleus coupling constraint, which
was at least two orders of magnitude bigger than that of the previous
international optimal constraint.
This study demonstrated the unique advantages of the spin-based amplifier to
study new physics theories beyond the standard model.
Reference:
Haowen Su et al, Search for exotic spin-dependent interactions with a
spin-based amplifier, Science Advances (2021).
DOI: 10.1126/sciadv.abi9535
Tags:
Physics