@article{10902/38546, year = {2025}, month = {10}, url = {https://hdl.handle.net/10902/38546}, abstract = {A search for the rare decay D0 --> m+m- is reported using proton-proton collision events at V¯s = 13.6 TeV collected by the CMS detector in 2022-2023, corresponding to an integrated luminosity of 64.5 fb-1. This is the first analysis to use a newly developed inclusive dimuon trigger, expanding the scope of the CMS flavor physics program. The search uses D0 mesons obtained from D*+ --> D0p+ decays. No significant excess is observed. A limit on the branching fraction of B(D0 --> m+m-) <2.4×10-9 at 95% confidence level is set. This is the most stringent upper limit set on any flavor changing neutral current decay in the charm sector.}, organization = {We congratulate our colleagues in the CERN accelerator departments for the excellent performance of the LHC and thank the technical and administrative staffs at CERN and at other CMS institutes for their contributions to the success of the CMS effort. In addition, we gratefully acknowledge the computing centres and personnel of the Worldwide LHC Computing Grid and other centres for delivering so effectively the computing infrastructure essential to our analyses. Finally, we acknowledge the enduring support for the construction and operation of the LHC, the CMS detector, and the supporting computing infrastructure provided by the following funding agencies: SC (Armenia), BMBWF and FWF (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, FAPERGS, and FAPESP (Brazil); MES and BNSF (Bulgaria); CERN; CAS, MoST, and NSFC (China); MINCIENCIAS (Colombia); MSES and CSF(Croatia); RIF (Cyprus); SENESCYT (Ecuador); ERC PRG, RVTT3 and MoER TK202 (Estonia); Academy of Finland, MEC, and HIP (Finland); CEA and CNRS/IN2P3 (France); SRNSF (Georgia); BMBF, DFG, and HGF (Germany); GSRI (Greece); NKFIH (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); MSIP and NRF (Republic of Korea); MES (Latvia); LMTLT (Lithuania); MOE and UM (Malaysia); BUAP,CINVESTAV,CONACYT,LNS,SEP,andUASLPFAI (Mexico); MOS (Montenegro); MBIE (New Zealand); PAEC(Pakistan); MES andNSC(Poland); FCT(Portugal); JINR (Dubna); MON, RosAtom, RAS, RFBR, and NRC KI (Russia); MESTD (Serbia); MICIU/AEI and PCTI (Spain); MOSTR (Sri Lanka); Swiss Funding Agencies (Switzerland); MST (Taipei); MHESI and NSTDA (Thailand); TUBITAK and TENMAK (Turkey); NASU (Ukraine); STFC (United Kingdom); DOE and NSF (USA).}, publisher = {American Physical Society}, publisher = {Physical Review Letters, 2025, 135(15), 151803}, title = {Search for the rare decay D0 --> m+m- in proton-proton collisions at V¯s = 13.6 TeV}, author = {Chekhovsky, V. and Hayrapetyan, A. and Makarenko, V. and Blanco Fernández, Sergio and Cabrillo Bartolomé, José Ibán and Calderón Tazón, Alicia and Duarte Campderros, Jorge and Fernández García, Marcos and Gómez Gramuglio, Gervasio and Lasaosa García, Clara and López Ruiz, Rubén and Martínez Rivero, Celso and Martínez Ruiz del Árbol, Pablo and Matorras Weinig, Francisco and Matorras Cuevas, Pablo and Navarrete Ramos, Efrén and Piedra Gómez, Jonatan and Scodellaro, Luca and Vila Álvarez, Iván and Vizán García, Jesús Manuel}, }