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| Light Degrees of Freedom from String/M theory framework |
| 2016-11-09
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Institute of Theoretical Physics |
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Chinese Academy of Sciences |
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Key Laboratory of Theoretical Physics |
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Seminar |
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Title
题目 |
Light Degrees of Freedom from String/M theory framework |
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Speaker
报告人 |
Dr. Chakrit Pongkitivanichkul |
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Affiliation
所在单位 |
中国科学院高能物理研究所 |
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Date
日期 |
2016年11月9日（星期三）下午 17:00 PM |
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Venue
地点 |
Room 6620,ITP new Building/理论物理所新楼6620报告厅 |
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Abstract
摘要 |
I will discuss two topics of light degrees of freedom from string/M theory,
namely, Axion Like Particles (ALPs) and neutrinos. The string/M theory
Axiverse - a plethora of very light ALPs with a vast range of masses -
is arguably a generic prediction of string/M theory. String/M theory
also tends to predict that the early Universe is dominated by moduli
fields. When the heavy moduli decay, before nucleosynthesis, they produce
dark radiation in the form of relativistic ALPs. Generically one estimates
that the number of relativistic species (Neff) grows with the number of
axions in the Axiverse, in contradiction to the observations that
Neff < 4. I will explain this problem in detail and suggest some possible
solutions to it. The second part of the talk I will discuss the origin
of neutrino mass from SO(10) arising from M Theory compactified on
a G2-manifold. This is linked to the problem of the breaking of the
extra U(1) gauge group, in the SU(5) x U(1) subgroup of SO(10), which
is achievable via a (generalised) Kolda-Martin mechanism. The resulting
neutrino masses arise from a combination of the seesaw mechanism and
induced R-parity breaking contributions. The rather complicated neutrino
mass matrix is analysed for one neutrino family and it is shown how
phenomenologically acceptable neutrino masses can emerge. |
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Contact Person
联系人 |
李田军 |
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