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arXiv 0910.2587hep-phastro-ph.COhep-ex
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看不见的剧变衰变成光暗物质

Invisible Upsilon decays into Light Dark Matter

Pierre Fayet

摘要:

在MSSM或N(n)MSSM中,不可见的psi和Upperdum衰变为轻中性伴子的过程比产生nu nubar的过程要小,即使轻自旋为0的粒子与夸克和中性伴子耦合。更一般地说,轻暗物质粒子通常是被禁止的,除非它们可以通过一种比弱相互作用(在较低能量下)更强的新相互作用而充分湮灭,如轻自旋1 U玻色子或标量暗物质的重费米子交换所诱导的。我们讨论了U玻色子,重费米子,或自旋0交换不可见的psi和Uppermant衰变的可能贡献。铀交换可能导致(但不一定)不可见的衰变进入光暗物质的重要分支。我们展示了如何得到正确的遗迹密度,以及足够小的不可见分支分数,以及由此产生的U耦合到普通粒子和暗物质的约束,特别是|c_chi.f_bV| < 5 × 10^-3,这是因为2 m_chi小于几个GeV。我们还解释了为什么没有独立于模型的方法来预测psi和Upperdum分支分数到轻暗物质,从暗物质湮灭截面在冻结时间。

英文摘要:

Invisible psi and Upsilon decays into light neutralinos, within the MSSM or N(n)MSSM, are smaller than for nu nubar production, even if light spin-0 particles are coupled to quarks and neutralinos. In a more general way, light dark matter particles are normally forbidden, unless they can annihilate sufficiently through a new interaction stronger than weak interactions (at lower energies), as induced by a light spin-1 U boson, or heavy-fermion exchanges in the case of scalar dark matter. We discuss the possible contributions of U-boson, heavy-fermion, or spin-0 exchanges to invisible psi and Upsilon decays. U-exchanges could lead, but not necessarily, to significant branching fractions for invisible decays into light dark matter. We show how one can get the correct relic density together with sufficiently small invisible branching fractions, and the resulting constraints on the U couplings to ordinary particles and dark matter, in particular |c_chi.f_bV| < 5 10^-3 from Upsilon decays, for 2 m_chi smaller than a few GeV. We also explain why there is no model-independent way to predict psi and Upsilon branching fractions into light dark matter, from dark matter annihilation cross sections at freeze-out time.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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