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تسجيل مستخدم جديدFirst Limit on the Direct Detection of Lightly Ionizing Particles for Electric Charge as Low as $e$/1000 with the textsc{Majorana Demonstrator}
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The textsc{Majorana Demonstrator} is an ultra low-background experiment searching for neutrinoless double-beta decay in $^{76}$Ge. The heavily shielded array of germanium detectors, placed nearly a mile underground at the Sanford Underground Research Facility in Lead, South Dakota, also allows searches for new exotic physics. Free, relativistic, lightly-ionizing particles with electrical charges less than $e$ are forbidden by the standard model but predicted by some of its extensions. If such particles exist, they might be detected in the textsc{Majorana Demonstrator} by searching for multiple- detector events with individual-detector energy depositions down to 1 keV. This search is background free and no candidate events have been found in 285 days of data taking. New direct-detection limits are set for the flux of lightly ionizing particles for charges as low as $e$/1000.
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The Majorana Demonstrator is an ultra low-background experiment searching for neutrinoless double-beta decay in $^{76}$Ge. The heavily shielded array of germanium detectors, placed nearly a mile underground at the Sanford Underground Research Facilit
y in Lead, South Dakota, also allows searches for new exotic physics. We present the first limits for tri-nucleon decay-specific modes and invisible decay modes for Ge isotopes. We find a half-life limit of $4.9 times 10^{25}$ yr for the decay $^{76}{rm Ge(ppn)} to {}^{73}{rm Zn} e^+pi^+$ and $4.7times10^{25}$ yr for the decay $^{76}{rm Ge(ppp)} to ^{73}{rm Cu} e^+pi^+pi^+$. The half-life limit for the invisible tri-proton decay mode of $^{76}$Ge was found to be $7.5times10^{24}$ yr.
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