2021 CAP Virtual Congress / Congrès virtuel de l'ACP 2021

Searches for Dark Photons at Belle II

9 Jun 2021, 16:10

10m

Underline Conference System

Oral not-in-competition (Graduate Student) / Orale non-compétitive (Étudiant(e) du 2e ou 3e cycle) Particle Physics / Physique des particules (PPD) W3-10 Candidates for Dark matter and Dark sector I (PPD) / Candidats pour matière et secteur sombres I (PPD)

Speaker

Ms Miho Wakai (University of British Columbia)

Description

Belle II is a B-Factory experiment designed to produce precision measurements of CP violation in the weak sector as well as search for Beyond the Standard Model particle physics. The $e^{+}{e}^{-}$ collisions are created by the SuperKEKB accelerator which has achieved a world record of instantaneous luminosity of $2.4\times {10}^{34}{\text{cm}}^{-2}{\text{s}}^{-1}$. One of the highest priorities for the early data of the experiment is the search for dark photons that decay to dark matter. A dark photon is a mediator within the dark sector which mixes with the Standard Model (SM) photon. The experimental signature is a single energetic photon observed in the detector. A dark photon would produce an excess of events in the single photon recoil mass. A particularly challenging case is when the visible photon carries the full beam energy, which corresponds to a low-mass dark photon. There is a significant background from the SM process $e^{+}{e}^{-}\to \gamma \gamma$, where one of the photons is missed due to detector imperfections. This has motivated us to study the structure of the sub-detectors and compare the data and Monte Carlo response. By understanding the photon detection sensitivity of the sub-detectors, we will estimate the background for dark photon studies. This talk will discuss the ''single photon search'' and the approach to quantifying this background.

Presentation materials

MihoWakai_CAP2021.pdf