New Limits on Neutrino Millicharge and Magnetic Moment from TEXONO Data

Greeshma Chandrabhanu^1,2*, Lakhwinder Singh^1,2, Henry Tsz-King Wong¹

¹Institute of Physics, Academia Sinica, Taipei, Taiwan
²Department of Physics, Central University of South Bihar, Gaya, Bihar, India

* Presenter:Greeshma Chandrabhanu, email:gchandrabhanu@as.edu.tw

Neutrinos provide a powerful probe for exploring physics beyond the Standard Model, drawing significant interest from both theoretical and experimental communities. The confirmation of non-zero neutrino masses has motivated extensive research into their electromagnetic properties, which originate from electroweak radiative corrections and could reveal signatures of new physics with profound astrophysical and cosmological implications. Recent experiments achieving sub-keV energy thresholds have set the most stringent direct bounds on neutrino magnetic moments and electric millicharge [1, 2]. To obtain accurate predictions of differential cross sections in this energy regime, it is crucial to include atomic effects. Advanced many-body computational approaches, such as the multi-configuration relativistic random-phase approximation (MCRRPA), provide precise modeling of atomic responses, going beyond the limitations of free-electron approximations. This discussion focuses on MCRRPA-based cross sections for neutrino millicharge interactions, which demonstrate notable enhancements in the sub-keV region. Using TEXONO data with a 200eV threshold, new constraints on both the neutrino millicharge and magnetic moment are also presented.


References
[1] Jiunn-Wei Chen et al. , Phys. Rev. D 91, 013005 (2015).
[2] Jiunn-Wei Chen et al. , Phys. Rev. D 90, 011301(R) (2014).

Keywords: Neutrino, Electromagnetic properties, Magnetic moment, Millicharge, Reactor experiments