Search for the exclusive $W$ boson hadronic decays $W^{\pm }\to {\pi }^{\pm }\gamma$, $W^{\pm }\to K^{\pm }\gamma$ and $W^{\pm }\to {\rho }^{\pm }\gamma$ with the ATLAS detector

Abstract

A search for the exclusive hadronic decays $W^{\pm }\to {\pi }^{\pm }\gamma$, $W^{\pm }\to K^{\pm }\gamma$ and $W^{\pm }\to {\rho }^{\pm }\gamma$ is performed using up to $140{\text{fb}}^{-1}$ of proton-proton collisions recorded with the ATLAS detector at a center-of-mass energy of $\sqrt{s}=13\text{TeV}$. These rare processes provide a test bench for the quantum chromodynamics factorization formalism used to calculate cross sections at colliders, as well as a probe of $W$ boson coupling to quarks and a new way to measure the $W$ boson mass through fully reconstructed decay products. The search results in the most stringent upper limit to date on the branching fractions $\mathcal{B}(W^{\pm }\to {\pi }^{\pm }\gamma )<1.9\times 10^{-6}$, $\mathcal{B}(W^{\pm }\to K^{\pm }\gamma )<1.7\times 10^{-6}$, $\mathcal{B}(W^{\pm }\to {\rho }^{\pm }\gamma )<5.2\times 10^{-6}$ at 95% confidence level.

36 pages in total, author list starting page 19, 2 figures, 2 tables, published in Phys. Rev. Lett. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2019-20

References in corpus (7)

• An Introduction to PYTHIA 8.2
• New parton distributions for collider physics
• Measurement of the $Z/{\gamma }^{\ast }$ boson transverse momentum distribution in $pp$ collisions at $\sqrt{s}$ = 7 TeV with the ATLAS detector
• Exclusive Radiative Decays of W and Z Bosons in QCD Factorization
• Interpolation between multi-dimensional histograms using a new non-linear moment morphing method
• Search for Higgs and $Z$ Boson Decays to $\varphi \gamma$ with the ATLAS Detector
• Search for W boson decays to three charged pions

Cited by in corpus (1)

• Rare and exclusive few-body decays of the Higgs, Z, W bosons, and the top quark