LHCb CollaborationAdeva Andany, BernardoBorsato, MartinoChobanova, VeronikaCid Vidal, XabierDosil Suárez, ÁlvaroFernández Prieto, AntonioGarcía Pardiñas, JuliánHernando Morata, José ÁngelLemos Cid, EdgarLucio Martínez, MiriamMartínez Santos, DiegoPlo Casasus, MáximoPrisciandaro, JessicaRamos Pernas, MiguelRomero Vidal, AntonioSaborido Silva, Juan JoséSanmartín Sedes, BraisSantamarina Ríos, CibránVázquez Regueiro, PabloVieites Díaz, MaríaVázquez Sierra, CarlosGallas Torreira, Abraham Antonio2020-05-202020-05-202017Collaboration, L. (2017). Search for CP violation in the phase space of D0→ π π− π π− decays. Physics Letters B, 769, 345-3560370-2693http://hdl.handle.net/10347/22484A search for time-integrated CPviolation 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 CPasymmetries and, for the first time, is extended to probe the P-odd case. Using proton–proton collision data corresponding to an integrated luminosity of 3.0fb−1collected by the LHCb detector at centre-of-mass energies of √s=7TeVand 8TeV, the world’s best sensitivity to CPviolation in this decay is obtained. The data are found to be consistent with the hypothesis of CPsymmetry 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 CPnon-conservation of 2.7 standard deviations.eng©2017 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP3.http://creativecommons.org/licenses/by/4.0/journal article10.1016/j.physletb.2017.03.0621873-2445open access