On measurement of photon polarization in radiative penguin B decays to baryons

P. Pakhlov; T. Uglov

doi:10.1140/epjc/s10052-021-09528-4

EPJ

a
b
c
d
e
ap
st
h
plus
ds
pv
ti
qt
am
n

2023 Impact factor 4.2

Particles and Fields

Open Access

Eur. Phys. J. C (2021) 81: 759
https://doi.org/10.1140/epjc/s10052-021-09528-4

Regular Article - Experimental Physics

On measurement of photon polarization in radiative penguin B decays to baryons

P. Pakhlov¹^,2 and T. Uglov¹^b

¹ P. N. Lebedev Physical Institute of the RAS, Moscow, Russia
² Higher School of Economics, Moscow, Russia

^b uglov.timofey@gmail.com

Received: 12 May 2021
Accepted: 6 August 2021
Published online: 21 August 2021

Abstract

A measurement of the photon polarization in radiative penguin B decays provides a test of the Standard Model and a probe for New Physics, that can lead to a deviation from the Standard Model prediction of left-handed photons in $b \to s γ$ $b\rightarrow s \gamma$ . We propose a new method to measure the photon polarization using the baryonic decay $B^{-} \to Λ \bar{p} γ$ $B^- \rightarrow \Lambda \bar{p} \gamma$ . The P-violating $Λ$ $\Lambda$ -hyperon decay allows a measurement of the $Λ$ $\Lambda$ helicity to be performed, which can be uniquely related to the photon polarization in a model-independent way. The $B^{-} \to Λ \bar{p} γ$ $B^- \rightarrow \Lambda \bar{p} \gamma$ decay was recently measured to have a large branching fraction providing a possibility to get meaningful results with the data already available at LHC and B-factory experiments. An increase of the B-meson sample at high luminosity LHC experiments and Belle II should provide a really stringent test by using this method already in the near future.

© The Author(s) 2021

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.