Abstract
A search for CP violation in the decay Λ 0 b → pK − μ + μ − is presented. This decay is mediated by flavour-changing neutral-current transitions in the Standard Model and is potentially sensitive to new sources of CP violation. The study is based on a data sample of proton-proton collisions recorded with the LHCb experiment, corresponding to an integrated luminosity of 3 fb−1. The Λ 0 b → pK − μ + μ − decay is observed for the first time, and two observables that are sensitive to different manifestations of CP violation are measured, \( \Delta {\mathcal{A}}_{CP}\equiv {\mathcal{A}}_{CP}\left({\Lambda}_b^0\to p{K}^{-}{\mu}^{+}{\mu}^{-}\right)-{\mathcal{A}}_{CP}\left({\Lambda}_b^0\to p{K}^{-}J/\psi \right) \) and a \( {a}_{CP}^{\widehat{T}\hbox{-} odd} \), where the latter is based on asymmetries in the angle between the μ + μ − and pK − decay planes.
These are measured to be
and no evidence for CP violation is found.
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ArXiv ePrint: 1703.00256
Deceased (J. Blouw, I. Raniuk, P. Rodriguez Perez)
C. Baesso, M. Cruz Torres and C. Göbel are associated to Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
J. He, X. Lyu, D. Vieira, Y. Zheng, L. Sun, Y. Xie, H. Yin and J. Yu are associated to Center for High Energy Physics, Tsinghua University, Beijing, China
D. A. Milanes, I. A. Monroy and J. A. Rodriguez Lopez are associated to LPNHE, Université Pierre et Marie Curie, Université Paris Diderot, CNRS/IN2P3, Paris, France
O. Grünberg, M. Heß, H. Viemann and R. Waldi are associated to Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
T. Likhomanenko, A. Malinin, O. Morgunova, A. Nogay, A. Petrov and V. Shevchenko are associated to Institute of Theoretical and Experimental Physics (ITEP), Moscow, Russia
L. M. Garcia Martin, F. Martinez Vidal, A. Oyanguren, C. Remon Alepuz, P. Ruiz Valls and C. Sanchez Mayordomo are associated to ICCUB, Universitat de Barcelona, Barcelona, Spain
C. J. G. Onderwater is associated to Nikhef National Institute for Subatomic Physics, Amsterdam, The Netherlands
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The LHCb collaboration., Aaij, R., Adeva, B. et al. Observation of the decay Λ 0 b → pK − μ + μ − and a search for CP violation. J. High Energ. Phys. 2017, 108 (2017). https://doi.org/10.1007/JHEP06(2017)108
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DOI: https://doi.org/10.1007/JHEP06(2017)108