## This content will become publicly available on February 13, 2020

## $$\sin ^{2}\theta _{W}$$ estimate and neutrino electromagnetic properties from low-energy solar data

## Abstract

We report new values of weak-mixing angle ($$\sin ^{2}\theta _{W}$$)$,$ neutrino effective magnetic moment and the charge radius using the lowest-energy (to-date) solar neutrino data of pp, $$^{7}$$Be and pep spectra from phase-I and phase-II runs of Borexino experiment. The best-fit values are $$\sin ^{2}\theta _{W}=$$0.235$$\pm $$0.019 with a precision comparable to that of the combined reactor and accelerator very short-baseline experiments and $$\mu _{\nu }^{eff}\leq 8.7\times 10^{-12}\mu _{B}$$ at 90% C.L. with a factor of 3 improvement than the previous bounds. This leads to the improvement of all the related magnetic moment matrix elements for the Majorana-type and Dirac-type in mass basis and also improvement on bounds on the flavor magnetic moment states. The bounds on the neutrino charged radii turn out to be $$-0.82\times 10^{-32}$$cm$$^{2}\leq \left \langle r_{\nu _{e}}^{2}\right \rangle \ \leq 1.27\times 10^{-32}$$ cm$$^{2}\ $$and $$-9\times 10^{-32}$$cm$$^{2}\leq \left \langle r_{\nu _{\mu },\nu _{\tau }}^{2}\right \rangle \ \leq 3.1\times 10^{-31}$$ cm$$^{2}\ $$ at 90% C.L..

- Authors:

- Fermilab

- Publication Date:

- Research Org.:
- Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

- Sponsoring Org.:
- USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)

- OSTI Identifier:
- 1487070

- Report Number(s):
- arXiv:1709.02930; FERMILAB-PUB-18-444-ND-T

1622733

- Grant/Contract Number:
- AC02-07CH11359

- Resource Type:
- Accepted Manuscript

- Journal Name:
- J.Phys.

- Additional Journal Information:
- Journal Volume: G46; Journal Issue: 3

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

### Citation Formats

```
Khan, Amir N. $\sin ^{2}\theta _{W}$ estimate and neutrino electromagnetic properties from low-energy solar data. United States: N. p., 2019.
Web. doi:10.1088/1361-6471/ab0057.
```

```
Khan, Amir N. $\sin ^{2}\theta _{W}$ estimate and neutrino electromagnetic properties from low-energy solar data. United States. doi:10.1088/1361-6471/ab0057.
```

```
Khan, Amir N. Wed .
"$\sin ^{2}\theta _{W}$ estimate and neutrino electromagnetic properties from low-energy solar data". United States. doi:10.1088/1361-6471/ab0057.
```

```
@article{osti_1487070,
```

title = {$\sin ^{2}\theta _{W}$ estimate and neutrino electromagnetic properties from low-energy solar data},

author = {Khan, Amir N.},

abstractNote = {We report new values of weak-mixing angle ($\sin ^{2}\theta _{W}$)$,$ neutrino effective magnetic moment and the charge radius using the lowest-energy (to-date) solar neutrino data of pp, $^{7}$Be and pep spectra from phase-I and phase-II runs of Borexino experiment. The best-fit values are $\sin ^{2}\theta _{W}=$0.235$\pm $0.019 with a precision comparable to that of the combined reactor and accelerator very short-baseline experiments and $\mu _{\nu }^{eff}\leq 8.7\times 10^{-12}\mu _{B}$ at 90% C.L. with a factor of 3 improvement than the previous bounds. This leads to the improvement of all the related magnetic moment matrix elements for the Majorana-type and Dirac-type in mass basis and also improvement on bounds on the flavor magnetic moment states. The bounds on the neutrino charged radii turn out to be $-0.82\times 10^{-32}$cm$^{2}\leq \left \langle r_{\nu _{e}}^{2}\right \rangle \ \leq 1.27\times 10^{-32}$ cm$^{2}\ $and $-9\times 10^{-32}$cm$^{2}\leq \left \langle r_{\nu _{\mu },\nu _{\tau }}^{2}\right \rangle \ \leq 3.1\times 10^{-31}$ cm$^{2}\ $ at 90% C.L..},

doi = {10.1088/1361-6471/ab0057},

journal = {J.Phys.},

number = 3,

volume = G46,

place = {United States},

year = {2019},

month = {2}

}