Davoudiasl Hooman
Department of Physics, Brookhaven National Laboratory, Upton, New York 11973, USA.
Phys Rev Lett. 2015 Feb 6;114(5):051802. doi: 10.1103/PhysRevLett.114.051802. Epub 2015 Feb 4.
A sub-GeV dark sector fermion X can have baryon-number-violating interactions induced by high-scale physics, leading to nucleon decay into X+meson and neutron→X+photon. Such processes can mimic standard search modes containing a neutrino, but have different kinematics and may have escaped detection. If a dark force mediated by a light vector Z(d) acts on X, depending on parameters, neutron→X+Z(d) can be important. In typical scenarios, Z(d) decays into ℓ(+)ℓ(-), where ℓ=e,μ, with an order unity branching fraction. Nucleon decay searches can potentially uncover new dark states that are otherwise inaccessible, due to their negligible coupling to ordinary matter or cosmological abundance.
一个低于GeV的暗区费米子X可能具有由高标度物理诱导的违反重子数的相互作用，导致核子衰变成X+介子以及中子→X+光子。此类过程可能会模拟包含中微子的标准搜索模式，但具有不同的运动学特征，可能未被探测到。如果由轻矢量Z(d)介导的暗力作用于X，根据参数不同，中子→X+Z(d)可能很重要。在典型场景中，Z(d)衰变成ℓ(+)ℓ(-)，其中ℓ = e、μ，分支比约为1。核子衰变搜索有可能发现新的暗态，这些暗态由于与普通物质的耦合可忽略不计或宇宙丰度极低，否则难以被发现。
