Search for CP violation in the phase space of D0 → π+π−π+π− decays

LHCb Collaboration, R Aaij, Marco Adinolfi, John Benton, Emma Buchanan, Andrew Cook, Jeremy Dalseno, Sam Harnew, James Kariuki, Paras Naik, Konstantinos Petridis, Gabriela Pomery, Eugenia Price, Claire Prouve, Renato Quagliani, Jonas Rademacker, Sophie Richards, Daniel Saunders, Nicola Skidmore, Jaap Velthuis

Research output: Contribution to journalArticle (Academic Journal)peer-review

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A search for time-integrated CP violation in the Cabibbo-suppressed decay D0 → π+π−π+π− is
performed using an unbinned, model-independent technique known as the energy test. This is the first
application of the energy test in four-body decays. The search is performed for P-even CP asymmetries
and, for the first time, is extended to probe the P-odd case. Using proton–proton collision data
corresponding to an integrated luminosity of 3.0 fb−1 collected by the LHCb detector at centre-ofmass
energies of √s = 7 TeV and 8 TeV, the world’s best sensitivity to CP violation in this decay is
obtained. The data are found to be consistent with the hypothesis of CP symmetry with a p-value of
(4.6 ± 0.5)% in the P-even case, and marginally consistent with a p-value of (0.6 ± 0.2)% in the P-odd
case, corresponding to a significance for CP non-conservation of 2.7 standard deviations.
Original languageEnglish
Pages (from-to)345-356
JournalPhysics Letters B
Publication statusPublished - 10 Jun 2017


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