Search for the $CP$-violating strong decays $\eta \to {\pi }^{+}{\pi }^{-}$ and ${\eta }^{\prime }(958)\to {\pi }^{+}{\pi }^{-}$

Abstract

A search for the $CP$-violating strong decays $\eta \to {\pi }^{+}{\pi }^{-}$ and ${\eta }^{\prime }(958)\to {\pi }^{+}{\pi }^{-}$ has been performed using approximately $2.5\times 10^7$ events of each of the decays $D^{+}\to {\pi }^{+}{\pi }^{+}{\pi }^{-}$ and $D_s^{+}\to {\pi }^{+}{\pi }^{+}{\pi }^{-}$, recorded by the LHCb experiment. The data set corresponds to an integrated luminosity of 3.0 fb${}^{-1}$ of $pp$ collision data recorded during LHC Run 1 and 0.3 fb${}^{-1}$ recorded in Run 2. No evidence is seen for $D_{(s)}^{+}\to {\pi }^{+}{\eta }^{(\prime )}$ with ${\eta }^{(\prime )}\to {\pi }^{+}{\pi }^{-}$, and upper limits at 90% confidence level are set on the branching fractions, $\mathcal{B}(\eta \to {\pi }^{+}{\pi }^{-})<1.6\times 10^{-5}$ and $\mathcal{B}({\eta }^{\prime }\to {\pi }^{+}{\pi }^{-})<1.8\times 10^{-5}$. The limit for the $\eta$ decay is comparable with the existing one, while that for the ${\eta }^{\prime }$ is a factor of three smaller than the previous limit.

arXiv commentAll figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-046.html

References in corpus (21)

• PYTHIA 6.4 Physics and Manual
• PYTHIA 6.2 Physics and Manual
• A Brief Introduction to PYTHIA 8.1
• Big-Bang Nucleosynthesis
• LHCb Detector Performance
• PHOTOS Monte Carlo: a precision tool for QED corrections in Z and W decays
• The LHCb Trigger and its Performance in 2011
• Boosted Decision Trees as an Alternative to Artificial Neural Networks for Particle Identification
• Decay Chain Fitting with a Kalman Filter
• The Strong CP Problem and Axions
• Measurement of Prompt Charm Meson Production Cross Sections in p anti-p Collisions at s**(1/2) = 1.96 TeV
• Measurements of prompt charm production cross-sections in $pp$ collisions at $\sqrt{s}=13\mathrm{TeV}$
• Exclusive Measurement of the eta --> pi+ pi- gamma Decay
• Measurements of prompt charm production cross-sections in $pp$ collisions at $\sqrt{s}=5$TeV
• Planck-Scale Physics and Solutions to the Strong CP Problem without Axion
• Is strong CP invariance due to a massless up quark?
• Upper limit on the eta -> pi+pi- branching ratio with the KLOE experiment
• Upper Limit on the eta to gamma gamma gamma Branching Ratio with the KLOE Detector
• Strong CP violation and the neutron electric dipole form factor
• Search for CP and $P$ violating pseudoscalar decays into $\pi \pi$
• The Strong CP Problem, String Theory and the Nelson-Barr Mechanism

Cited by in corpus (5)

• Precision tests of fundamental physics with $\eta$ and ${\eta }^{\prime }$ mesons
• CP-violating decays of the pseudoscalars eta and eta' and their connection to the electric dipole moment of the neutron
• Bounds on rare decays of $\eta$ and ${\eta }^{\prime }$ mesons from the neutron EDM
• Updated limits on the CP violating $\eta \pi \pi$ and ${\eta }^{\prime }\pi \pi$ couplings derived from the neutron EDM
• Deuteron EDM induced by CP violating couplings of pseudoscalar mesons