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Title:

Particle Physics Models of Inflation in Supergravity and Grand Unification

Description:

In the first part of this thesis, we study classes of hybrid and chaotic inflation models in four-dimensional N=1 supergravity. Therein, the eta-problem can be resolved relying on fundamental symmetries in the Kaehler potential. Concretely, we investigate explicit realizations of superpotentials, in which the flatness of the inflaton potential i...

In the first part of this thesis, we study classes of hybrid and chaotic inflation models in four-dimensional N=1 supergravity. Therein, the eta-problem can be resolved relying on fundamental symmetries in the Kaehler potential. Concretely, we investigate explicit realizations of superpotentials, in which the flatness of the inflaton potential is protected at tree level by a shift symmetry or a Heisenberg symmetry in the Kaehler potential. In the latter case, the associated modulus field can be stabilized during inflation by supergravity effects. In the context of hybrid inflation, a novel class of models, to which we refer as "tribrid inflation," turns out to be particularly compatible with such symmetry solutions to the eta-problem. Radiative corrections due to operators in the superpotential, which break the respective symmetry, generate the required small slope of the inflaton potential. Additional effective operators in the Kaehler potential can reduce the predicted spectral index so that it agrees with latest observational data. Within a model of chaotic inflation in supergravity with a quadratic potential, we apply the Heisenberg symmetry to allow for viable inflation with super-Planckian field values, while the associated modulus is stabilized. We show that radiative corrections are negligible in this context. In the second part, the tribrid inflation models are extended to realize gauge non-singlet inflation. This is applied to the matter sector of supersymmetric Grand Unified Theories based on the Pati-Salam gauge group. For the specific scenario in which the right-handed sneutrino is the inflaton, we study the scalar potential in a D-flat valley. We show that despite potentially dangerous two-loop corrections, the required flatness of the potential can be maintained. The reason for this is the strong suppression of gauge interactions of the inflaton field due to its symmetry breaking vacuum expectation value. In addition, the production of stable magnetic monopoles at the end of the stage of inflation can be avoided. Finally, we sketch how in tribrid inflation models the concepts discussed in the two parts can be combined to realize inflation via Heisenberg symmetry in local supersymmetric SO(10) grand unification. Minimize

Publisher:

Ludwig-Maximilians-Universität München

Year of Publication:

2010-12-03

Document Type:

Dissertation ; NonPeerReviewed

Subjects:

Fakultät für Physik

Fakultät für Physik Minimize

DDC:

539 Modern physics *(computed)*

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http://edoc.ub.uni-muenchen.de/12412/

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Title:

SUGRA Hybrid Inflation with Shift Symmetry

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We propose a solution to the eta-problem in supergravity (SUGRA) hybrid inflation using a Nambu-Goldstone-like shift symmetry within a new class of models. The flatness of the tree-level inflaton potential is ensured by shift symmetry invariance of the Kaehler potential, while a small symmetry breaking term in the superpotential gives rise to a ...

We propose a solution to the eta-problem in supergravity (SUGRA) hybrid inflation using a Nambu-Goldstone-like shift symmetry within a new class of models. The flatness of the tree-level inflaton potential is ensured by shift symmetry invariance of the Kaehler potential, while a small symmetry breaking term in the superpotential gives rise to a slope of the potential at loop-level. In the proposed class of inflation models, potentially dangerous couplings between the inflaton and the moduli sector are avoided. We also discuss under which conditions the predicted spectral index can be in agreement with the best-fit-value of the latest WMAP observation n_s ~ 0.96, corresponding to a hilltop-type inflaton potential at loop-level. ; Comment: 7 pages, 3 figures; appendix and references added; version published in PLB Minimize

Year of Publication:

2009-02-17

Document Type:

text

Subjects:

High Energy Physics - Phenomenology ; Astrophysics - Cosmology and Extragalactic Astrophysics ; High Energy Physics - Theory

High Energy Physics - Phenomenology ; Astrophysics - Cosmology and Extragalactic Astrophysics ; High Energy Physics - Theory Minimize

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Title:

Tribrid Inflation in Supergravity

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We propose a novel class of F-term hybrid inflation models in supergravity (SUGRA) where the $\eta$-problem is resolved using either a Heisenberg symmetry or a shift symmetry of the Kaehler potential. In addition to the inflaton and the waterfall field, this class (referred to as tribrid inflation) contains a third 'driving' field which contribu...

We propose a novel class of F-term hybrid inflation models in supergravity (SUGRA) where the $\eta$-problem is resolved using either a Heisenberg symmetry or a shift symmetry of the Kaehler potential. In addition to the inflaton and the waterfall field, this class (referred to as tribrid inflation) contains a third 'driving' field which contributes the large vacuum energy during inflation by its F-term. In contrast to the ''standard'' hybrid scenario, it has several attractive features due to the property of vanishing inflationary superpotential (W_inf=0) during inflation. While the symmetries of the Kaehler potential ensure a flat inflaton potential at tree-level, quantum corrections induced by symmetry breaking terms in the superpotential generate a slope of the potential and lead to a spectral tilt consistent with recent WMAP observations. ; Comment: To appear in the proceedings of SUSY09; 5 pages Minimize

Year of Publication:

2009-08-12

Document Type:

text

Subjects:

High Energy Physics - Phenomenology ; Astrophysics - Cosmology and Nongalactic Astrophysics ; High Energy Physics - Theory

High Energy Physics - Phenomenology ; Astrophysics - Cosmology and Nongalactic Astrophysics ; High Energy Physics - Theory Minimize

DDC:

539 Modern physics *(computed)*

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Title:

Tribrid Inflation in Supergravity.

Author:

Description:

We propose a novel class of F-term hybrid inflation models in supergravity (SUGRA) where the $\eta$-problem is resolved using either a Heisenberg symmetry or a shift symmetry of the Kaehler potential. In addition to the inflaton and the waterfall field, this class (referred to as tribrid inflation) contains a third 'driving' field which contribu...

We propose a novel class of F-term hybrid inflation models in supergravity (SUGRA) where the $\eta$-problem is resolved using either a Heisenberg symmetry or a shift symmetry of the Kaehler potential. In addition to the inflaton and the waterfall field, this class (referred to as tribrid inflation) contains a third 'driving' field which contributes the large vacuum energy during inflation by its F-term. In contrast to the ''standard'' hybrid scenario, it has several attractive features due to the property of vanishing inflationary superpotential (W_inf=0) during inflation. While the symmetries of the Kaehler potential ensure a flat inflaton potential at tree-level, quantum corrections induced by symmetry breaking terms in the superpotential generate a slope of the potential and lead to a spectral tilt consistent with recent WMAP observations. Minimize

Year of Publication:

2010

Source:

American Institute of Physics Conference Proceedings, 1200, 1007-1010 (2010) ; SUSY09: 7th International Conference on Supersymmetry and the Unification of Fundamental Interactions, 1007-1010 (2010)

American Institute of Physics Conference Proceedings, 1200, 1007-1010 (2010) ; SUSY09: 7th International Conference on Supersymmetry and the Unification of Fundamental Interactions, 1007-1010 (2010) Minimize

Document Type:

Conference-Paper

Subjects:

Phenomenology of High Energy Physics

Phenomenology of High Energy Physics Minimize

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Title:

Gauge Non-Singlet Inflation in SUSY GUTs

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Description:

We explore the novel possibility that the inflaton responsible for cosmological inflation is a gauge non-singlet in supersymmetric (SUSY) Grand Unified Theories (GUTs). For definiteness we consider SUSY hybrid inflation where we show that the scalar components of gauge non-singlet superfields, together with fields in conjugate representations, m...

We explore the novel possibility that the inflaton responsible for cosmological inflation is a gauge non-singlet in supersymmetric (SUSY) Grand Unified Theories (GUTs). For definiteness we consider SUSY hybrid inflation where we show that the scalar components of gauge non-singlet superfields, together with fields in conjugate representations, may form a D-flat direction suitable for inflation. We apply these ideas to SUSY models with an Abelian gauge group, a Pati-Salam gauge group and finally Grand Unified Theories based on SO(10) where the scalar components of the matter superfields in the $\sixteen$s may combine with a single $\bar {sixteen}$ to form the inflaton, with the right-handed sneutrino direction providing a possible viable trajectory for inflation. Assuming sneutrino inflation, we calculate the one-loop Coleman-Weinberg corrections and the two-loop corrections from gauge interactions giving rise to the "gauge \eta-problem" and show that both corrections do not spoil inflation, and the monopole problem can be resolved. The usual \eta-problem arising from supergravity may also be resolved using a Heisenberg symmetry. ; Comment: 41 pages, 6 figures; minor changes; version published in JHEP Minimize

Year of Publication:

2010-03-16

Document Type:

text

Subjects:

High Energy Physics - Phenomenology ; Astrophysics - Cosmology and Nongalactic Astrophysics ; High Energy Physics - Theory

High Energy Physics - Phenomenology ; Astrophysics - Cosmology and Nongalactic Astrophysics ; High Energy Physics - Theory Minimize

DDC:

539 Modern physics *(computed)*

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Title:

Chaotic Inflation in Supergravity with Heisenberg Symmetry

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We propose the introduction of a Heisenberg symmetry of the Kahler potential to solve the problems with chaotic inflation in supergravity, as a viable alternative to the use of shift symmetry. The slope of the inflaton potential emerges from a small Heisenberg symmetry breaking term in the superpotential. The modulus field of the Heisenberg symm...

We propose the introduction of a Heisenberg symmetry of the Kahler potential to solve the problems with chaotic inflation in supergravity, as a viable alternative to the use of shift symmetry. The slope of the inflaton potential emerges from a small Heisenberg symmetry breaking term in the superpotential. The modulus field of the Heisenberg symmetry is stabilized and made heavy with the help of the large vacuum energy density during inflation. The observable predictions are indistinguishable from those of typical chaotic inflation models, however the form of the inflationary superpotential considered here may be interpreted in terms of sneutrino inflation arising from certain classes of string theory. ; Comment: 6 pages, 1 figure; reference added; version published in PLB Minimize

Year of Publication:

2009-05-06

Document Type:

text

Subjects:

High Energy Physics - Theory ; Astrophysics - Cosmology and Extragalactic Astrophysics ; High Energy Physics - Phenomenology

High Energy Physics - Theory ; Astrophysics - Cosmology and Extragalactic Astrophysics ; High Energy Physics - Phenomenology Minimize

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Title:

Solving the $\eta$-Problem in Hybrid Inflation with Heisenberg Symmetry and Stabilized Modulus

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Description:

We propose a class of models in which the $\eta$-problem of supersymmetric hybrid inflation is resolved using a Heisenberg symmetry, where the associated modulus field is stabilized and made heavy with the help of the large vacuum energy during inflation without any fine-tuning. The proposed class of models is well motivated both from string the...

We propose a class of models in which the $\eta$-problem of supersymmetric hybrid inflation is resolved using a Heisenberg symmetry, where the associated modulus field is stabilized and made heavy with the help of the large vacuum energy during inflation without any fine-tuning. The proposed class of models is well motivated both from string theory considerations, since it includes the commonly encountered case of no-scale supergravity Kaehler potential, and from the perspective of particle physics since a natural candidate for the inflaton in this class of models is the right-handed sneutrino which is massless during the inflationary epoch, and subsequently acquires a large mass at the end of inflation. We study a specific example motivated by sneutrino hybrid inflation with no-scale supergravity in some detail, and show that the spectral index may lie within the latest WMAP range, while the tensor-to-scalar ratio is very small. ; Comment: 27 pages, 4 figures; appendix and reference added; version published in JCAP Minimize

Year of Publication:

2008-08-18

Document Type:

text

Subjects:

High Energy Physics - Phenomenology ; Astrophysics ; High Energy Physics - Theory

High Energy Physics - Phenomenology ; Astrophysics ; High Energy Physics - Theory Minimize

DDC:

539 Modern physics *(computed)*

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Title:

Sneutrino Hybrid Inflation and Nonthermal Leptogenesis

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In sneutrino hybrid inflation the superpartner of one of the right-handed neutrinos involved in the seesaw mechanism plays the role of the inflaton field. It obtains its large mass after the "waterfall" phase transition which ends hybrid inflation. After this phase transition the oscillations of the sneutrino inflaton field may dominate the univ...

In sneutrino hybrid inflation the superpartner of one of the right-handed neutrinos involved in the seesaw mechanism plays the role of the inflaton field. It obtains its large mass after the "waterfall" phase transition which ends hybrid inflation. After this phase transition the oscillations of the sneutrino inflaton field may dominate the universe and efficiently produce the baryon asymmetry of the universe via nonthermal leptogenesis. We investigate the conditions under which inflation, with primordial perturbations in accordance with the latest WMAP results, as well as successful nonthermal leptogenesis can be realized simultaneously within the sneutrino hybrid inflation scenario. We point out which requirements successful inflation and leptogenesis impose on the seesaw parameters, i.e. on the Yukawa couplings and the mass of the right-handed (s)neutrino, and derive the predictions for the CMB observables in terms of the right-handed (s)neutrino mass and the other relevant model parameters. ; Comment: 27 pages, 4 figures; minor changes; version published in JCAP Minimize

Year of Publication:

2010-07-05

Document Type:

text

Subjects:

High Energy Physics - Phenomenology ; Astrophysics - Cosmology and Extragalactic Astrophysics ; High Energy Physics - Theory

High Energy Physics - Phenomenology ; Astrophysics - Cosmology and Extragalactic Astrophysics ; High Energy Physics - Theory Minimize

DDC:

539 Modern physics *(computed)*

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Title:

Solving the $\eta$-Problem in Hybrid Inflation with Heisenberg Symmetry and Stabilized Modulus

Author:

Description:

We propose a class of models in which the $\eta$-problem of supersymmetric hybrid inflation is resolved using a Heisenberg symmetry, where the associated modulus field is stabilized and made heavy with the help of the large vacuum energy during inflation without any fine-tuning. The proposed class of models is well motivated both from string the...

We propose a class of models in which the $\eta$-problem of supersymmetric hybrid inflation is resolved using a Heisenberg symmetry, where the associated modulus field is stabilized and made heavy with the help of the large vacuum energy during inflation without any fine-tuning. The proposed class of models is well motivated both from string theory considerations, since it includes the commonly encountered case of no-scale supergravity Kaehler potential, and from the perspective of particle physics since a natural candidate for the inflaton in this class of models is the right-handed sneutrino which is massless during the inflationary epoch, and subsequently acquires a large mass at the end of inflation. We study a specific example motivated by sneutrino hybrid inflation with no-scale supergravity in some detail, and show that the spectral index may lie within the latest WMAP range, while the tensor-to-scalar ratio is very small. Minimize

Year of Publication:

2009

Source:

Journal of Cosmology and Astroparticle Physics, 040 (2009)

Journal of Cosmology and Astroparticle Physics, 040 (2009) Minimize

Document Type:

Article

Subjects:

Astroparticle Physics

Astroparticle Physics Minimize

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Title:

Gauge Non-Singlet Inflation in SUSY GUTs

Author:

Description:

We explore the novel possibility that the inflaton responsible for cosmological inflation is a gauge non-singlet in supersymmetric (SUSY) Grand Unified Theories (GUTs). For definiteness we consider SUSY hybrid inflation where we show that the scalar components of gauge non-singlet superfields, together with fields in conjugate representations, m...

We explore the novel possibility that the inflaton responsible for cosmological inflation is a gauge non-singlet in supersymmetric (SUSY) Grand Unified Theories (GUTs). For definiteness we consider SUSY hybrid inflation where we show that the scalar components of gauge non-singlet superfields, together with fields in conjugate representations, may form a D-flat direction suitable for inflation. We apply these ideas to SUSY models with an Abelian gauge group, a Pati-Salam gauge group and finally Grand Unified Theories based on SO(10) where the scalar components of the matter superfields in the $\sixteen$s may combine with a single $\bar {sixteen}$ to form the inflaton, with the right-handed sneutrino direction providing a possible viable trajectory for inflation. Assuming sneutrino inflation, we calculate the one-loop Coleman-Weinberg corrections and the two-loop corrections from gauge interactions giving rise to the "gauge \eta-problem" and show that both corrections do not spoil inflation, and the monopole problem can be resolved. The usual \eta-problem arising from supergravity may also be resolved using a Heisenberg symmetry. Minimize

Year of Publication:

2010

Source:

Journal of High Energy Physics, 100 (2010)

Journal of High Energy Physics, 100 (2010) Minimize

Document Type:

Article

Subjects:

Theoretical Physics

Theoretical Physics Minimize

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