Nikhef National Institute for Subatomic Physics, Amsterdam, The Netherlands.
Universidad de Santiago de Compostela, Santiago de Compostela, Spain.
Phys Rev Lett. 2014 Apr 4;112(13):131802. doi: 10.1103/PhysRevLett.112.131802. Epub 2014 Apr 3.
A search for heavy Majorana neutrinos produced in the B- → π+ μ- μ- decay mode is performed using 3 fb(-1) of integrated luminosity collected with the LHCb detector in pp collisions at center-of-mass energies of 7 and 8 TeV at the LHC. Neutrinos with masses in the range 250 to 5000 MeV and lifetimes from zero to 1000 ps are probed. In the absence of a signal, upper limits are set on the branching fraction B(B- → π+ μ- μ-) as functions of neutrino mass and lifetime. These limits are on the order of 10(-9) for short neutrino lifetimes of 1 ps or less. Limits are also set on the coupling between the muon and a possible fourth-generation neutrino.
使用 LHCb 探测器在 LHC 上的 7 TeV 和 8 TeV 质心能量下的 pp 碰撞中收集了 3 fb(-1)的积分亮度，对 B-→π+μ-μ-衰变模式中产生的重 Majorana 中微子进行了搜索。探测了质量在 250 到 5000 MeV 之间、寿命在 0 到 1000 ps 之间的中微子。在没有信号的情况下，根据中微子质量和寿命，设定了 B(B-→π+μ-μ-)分支比的上限。对于 1 ps 或更短的短寿命中微子，这些限制在 10(-9)的量级。还对可能的第四代中微子与μ子之间的耦合进行了限制。
