Flipped GUT Inflation

Transcription

1 Flipped GUT Inflation Technische Universität Dortmund Wei- Chih Huang IOP Academia Sinica arxiv: , 15XX.XXXX with John Ellis, Julia Harz, Tomás E. Gonzalo

2 Outline BICEP2 excitement and turmoil Inflation Model setup: flipped SU(5) U(1) Results Future work Conclusions and outlook

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4 arxiv: v2

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6 Planck

7 Why inflation? Large scale smoothness: Ø S HOR ~ (today) Ø S HOR ~ (CMBR) Ø S HOR ~ (BBN) Kolb&Turner, The Early Universe

8 Why inflation? Flatness problem: Daniel Baumann, TASI lecture 09

9 Inflation EvoluRon of the comoving Hubble radius, (a H) - 1 Daniel Baumann, TASI lecture 09

10 Slow-roll approximation Assuming isotropy and homogeneity, one obtains Friedmann-Robertson- Walker (FRW) metric for the spacetime of the universe: The equation of motion for the inflaton field reads Slow-roll conditions require: Two slow-roll parameters (inflation ends when ε 1 ): Baumann, MarRn et al,

11 Inflation observables In the slow-roll limit, we can expresses inflationary observables in terms of the slow-roll parameters, ε and η A s : scalar perturbation amplitude n s : spectral index r : tensor-to-scalar ratio N e : number of e-folds Baumann, MarRn et al,

12 Connection with GUT Given the previous formulas, one can link A s with r as: With the Planck measurement: A s =2.19*10-9 ( ), the inflationary potential is connected to r: V φ roughly at the GUT scale In this work, we consider hybrid models (Linde 91), where the GUT symmetry breaks dynamically after the end of inflation. (Hertzberg and Wilczek, )

13 Hybrid model ɸ is the inflaton and h is the Higgs field which is initially located at h=0 When ɸ rolls down to its minimum ɸ=0, h starts to move away from h=0 toward h=σ, ending inflation if ƛ*v > H, where H is the Hubble parameter Once h reaches h=σ, the gauge symmetry h carries is spontaneously broken. In other words, the end of inflation is followed by gauge symmetry breaking.

14 Monopoles and flipped SU(5) U(1) If we start from SU(5) breaking down to SU(3) SU(2) U(1), magnetic monopoles will be created ( t Hooft 74 and Polyakov 74). In the hybrid models, gauge symmetry breaking happens after the end of inflation and thus the generated magnetic monopoles do not get diluted and might exceed the observed dark matter relic abundance. To overcome the problem, we choose the flipped (non-simple) SU(5) U(1) model (de Rujula, Georgi & Glashow 80, Barr 82, Derendinger, Kim & Nanopoulos 84, Antoniadis, Ellis, Hagelin & Nanopoulos 87), where the residual SM U(1) Y is the linear combination of SU(5) U(1), i.e., no monopoles are produced.

15 Flipped SU(5) U(1) Tomas Gonzalo, Planck 2015

16 Complete superpotential reads: Flipped SU(5) U(1) Of which, the relevant terms are, where we choose ν c to be the inflaton,

17 The inflationary potential becomes Flipped SU(5) U(1) Since inflaton ν c are charged under SU(5) U(1), we also have the D-term contribution, which vanishes if during the inflation, : and, The resulting inflationary potential is simply chaotic inflation with a relative large r (~0.16):

18 Results with sneutrino as inflation

19 Results with sneutrino as inflation To impose constraints on other parameters, we requires: is stable at the beginning of the inflaron <h>~10 16 GeV acer inflaron with the help of soc SUSY breaking terms ; otherwise R- parity is violated and lepton number is also violated by one unit

20 Singlet as inflation with Ø During the inflaron, becomes: is a stable minimum. The inflaronary

21 Singlet as inflation

22 Future work With including more terms in superpotenral, this model can have lower tensor- to- scalar raro r, comparble with the latest. The new inflaronary potenral becomes: with

23 Future work One should consider how pre- rehearng affect the number of e- folds: Planck

24 Future work One should consider how pre- rehearng affect the number of e- folds: Planck

25 Conclusions We present a hybrid model based on flipped SU(5) U(1) The gauge symmetry breaking is dynamically driven by the inflaton, the right-handed sneutrino or the singlet scalar The inflationary potential is directly connected to the GUT scale and this model can reproduce inflationary observables but its tensor-to-scalar ratio is in tension with the latest Planck results

26 Outlooks Including more terms in superpotential, this model can accommodate smaller values of r Assuming instantaneous preheating, the number of e-folds are close to N * ~60 By carefully taking into account complex components of the inflaton fields, one have multi-field inflation with larger experimentally compatible regions of the parameter space