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SUMMARY:The PADME experiment at DAFNE Linac - Mauro Raggi (INFN\, Frascati
 )
DTSTART:20160513T150000Z
DTEND:20160513T160000Z
UID:TALK64769@talks.cam.ac.uk
CONTACT:Marco Nardecchia
DESCRIPTION:The long standing problem of reconciling the cosmological evid
 ence of the existence of dark matter with the lack of any clear experiment
 al observation of it\, has recently revived the idea that the new particle
 s are not directly connected with the Standard Model gauge fields\, but on
 ly through mediator fields or “portals”\, connecting our world with ne
 w “secluded” or “hidden” sectors. \nOne of the simplest models jus
 t adds an additional U(1) symmetry\, with its corresponding vector boson A
 '. All SM particles will be neutral under this symmetry\, while the new fi
 eld will couple to the charged particles of the SM with an effective milli
 -charge.\nAdditional interest arises from the observation that A' in the m
 ass range 1 MeV to 100 MeV and coupling charge of the order of 0.001\, wou
 ld justify the discrepancy\nbetween theory and observation for the muon an
 omalous magnetic moment\, (g − 2) of the muon.\nThis possibility has bee
 n recently disproved in the hypothesis that the A' decays to SM particles 
 only\, on the contrary if A' decays to dark sector particles\, almost all 
 of the available experimental constraints can be evaded and the dark photo
 n is still a valuable explanation for the muon (g-2) anomaly.\nAt the end 
 of 2015 INFN has formally approved a new experiment\, PADME\, to search fo
 r invisible decays of the A' at the DAFNE Linac in Frascati. The experimen
 t is designed to detect dark photon produced in positron on fixed target a
 nnihilation by measuring the final state missing mass. The collaboration a
 ims to complete the design and construction of the experiment by the end o
 f 2017 and to collect 10**13 positron on target by the end of 2018\, thus 
 allowing to reach the a sensitivity on the milli-charge of 0.001 up to a d
 ark photon mass of 26 MeV
LOCATION:Seminar Room B\, Rutherford Building\, Cavendish Laboratory
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